Sample records for glucocorticoid receptor down-regulation

  1. G protein-coupled receptor 30 down-regulates cofactor expression and interferes with the transcriptional activity of glucocorticoid.

    PubMed

    Ylikomi, Timo; Vienonen, Annika; Ahola, Tytti M

    2004-11-01

    G protein-coupled receptor 30 (GPR30) has previously been described to be important in steroid-mediated growth and to inhibit cell proliferation. Here we investigated whether the effect of GPR30 on cell growth is dependent on steroid hormone receptors. We stably introduced GPR30 in immortalized normal mammary epithelial (HME) cells using retroviruses for gene delivery. GPR30 inhibited the growth and proliferation of the cells. They expressed glucocorticoid receptor, but not estrogen or progesterone receptor. GPR30 down-regulated the expression of cofactor transcription intermediary factor 2 (TIF2) analyzed using quantitative RT-PCR analysis, and also diminished the expression of TIF2 at protein level analyzed by Western blotting using nuclear extracts from mammary epithelial cells. When HME cells were transiently transfected with the glucocorticoid response element MMTV-luc reporter plasmid, stable expression of GPR30 resulted in the abolition of ligand-induced transactivation of the promoter. In COS cells, transient transfection of GPR30 with glucocorticoid receptor alpha resulted in an abrogation of the MMTV-luc and GRE-luc reporter activities induced by dexamethasone. The results suggest a novel mechanism by which membrane-initiated signaling interferes with steroid signaling.

  2. Peroxisome proliferator-activated receptor {alpha} agonist-induced down-regulation of hepatic glucocorticoid receptor expression in SD rats

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Chen Xiang; Li Ming; Sun Weiping

    2008-04-18

    It was reported that glucocorticoid production was inhibited by fenofibrate through suppression of type-1 11{beta}-hydroxysteroid dehydrogenase gene expression in liver. The inhibition might be a negative-feedback regulation of glucocorticoid receptor (GR) activity by peroxisome proliferator-activated receptor alpha (PPAR{alpha}), which is quickly induced by glucocorticoid in the liver. However, it is not clear if GR expression is changed by fenofibrate-induced PPAR{alpha} activation. In this study, we tested this possibility in the liver of Sprague-Dawley rats. GR expression was reduced by fenofibrate in a time- and does-dependent manner. The inhibition was observed in liver, but not in fat and muscle. The corticosteronemore » level in the blood was increased significantly by fenofibrate. These effects of fenofibrate were abolished by PPAR{alpha} inhibitor MK886, suggesting that fenofibrate activated through PPAR{alpha}. In conclusion, inhibition of GR expression may represent a new molecular mechanism for the negative feedback regulation of GR activity by PPAR{alpha}.« less

  3. Glucocorticoid Regulation of the Vitamin D Receptor

    PubMed Central

    Hidalgo, Alejandro A.; Trump, Donald L.; Johnson, Candace S.

    2010-01-01

    Many studies indicate calcitriol has potent anti-tumor activity in different types of cancers. However, high levels of vitamin D can produce hypercalcemia in some patients. Glucocorticoids are used to ameliorate hypercalcemia and to enhance calcitriol anti-tumor activity. Calcitriol in combination with the glucocorticoid dexamethasone (Dex) increased vitamin D receptor (VDR) protein levels and ligand binding in squamous cell carcinoma VII (SCC). In this study we found that both calcitriol and Dex induce VDR- and glucocorticoid receptor (GR)-mediated transcription respectively, indicating both hormone receptors are active in SCC. Pre-treatment with Dex increases VDR-mediated transcription at the human CYP24A1 promoter. Whereas, pre-treatment with other steroid hormones, including dihydrotestosterone and R1881, has no effect on VDR-mediated transcription. Real-time PCR indicates treatment with Dex increases Vdr transcripts in a time-dependent manner, suggesting Dex may directly regulate expression of Vdr. Numerous putative glucocorticoid response elements (GREs) were found in the Vdr gene. Chromatin immunoprecipitation (ChIP) assay demonstrated GR binding at several putative GREs located within the mouse Vdr gene. However, none of the putative GREs studied increase GR-mediated transcription in luciferase reporter assays. In an attempt to identify the response element responsible for Vdr transcript regulation, future studies will continue to analyze newly identified GREs more distal from the Vdr gene promoter. PMID:20398752

  4. Down-regulated peroxisome proliferator-activated receptor γ (PPARγ) in lung epithelial cells promotes a PPARγ agonist-reversible proinflammatory phenotype in chronic obstructive pulmonary disease (COPD).

    PubMed

    Lakshmi, Sowmya P; Reddy, Aravind T; Zhang, Yingze; Sciurba, Frank C; Mallampalli, Rama K; Duncan, Steven R; Reddy, Raju C

    2014-03-07

    Chronic obstructive pulmonary disease (COPD) is a progressive inflammatory condition and a leading cause of death, with no available cure. We assessed the actions in pulmonary epithelial cells of peroxisome proliferator-activated receptor γ (PPARγ), a nuclear hormone receptor with anti-inflammatory effects, whose role in COPD is largely unknown. We found that PPARγ was down-regulated in lung tissue and epithelial cells of COPD patients, via both reduced expression and phosphorylation-mediated inhibition, whereas pro-inflammatory nuclear factor-κB (NF-κB) activity was increased. Cigarette smoking is the main risk factor for COPD, and exposing airway epithelial cells to cigarette smoke extract (CSE) likewise down-regulated PPARγ and activated NF-κB. CSE also down-regulated and post-translationally inhibited the glucocorticoid receptor (GR-α) and histone deacetylase 2 (HDAC2), a corepressor important for glucocorticoid action and whose down-regulation is thought to cause glucocorticoid insensitivity in COPD. Treating epithelial cells with synthetic (rosiglitazone) or endogenous (10-nitro-oleic acid) PPARγ agonists strongly up-regulated PPARγ expression and activity, suppressed CSE-induced production and secretion of inflammatory cytokines, and reversed its activation of NF-κB by inhibiting the IκB kinase pathway and by promoting direct inhibitory binding of PPARγ to NF-κB. In contrast, PPARγ knockdown via siRNA augmented CSE-induced chemokine release and decreases in HDAC activity, suggesting a potential anti-inflammatory role of endogenous PPARγ. The results imply that down-regulation of pulmonary epithelial PPARγ by cigarette smoke promotes inflammatory pathways and diminishes glucocorticoid responsiveness, thereby contributing to COPD pathogenesis, and further suggest that PPARγ agonists may be useful for COPD treatment.

  5. Xenobiotics and the Glucocorticoid Receptor

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Gulliver, Linda S M, E-mail: linda.gulliver@otago.

    Glucocorticoid Receptor (GR) is present in virtually every human cell type. Representing a nuclear receptor superfamily, GR has several different isoforms essentially acting as ligand-dependent transcription factors, regulating glucocorticoid-responsive gene expression in both a positive and a negative manner. Although the natural ligand of the Glucocorticoid Receptor, glucocorticoids (GC) represent only some of the multiple ligands for GR. Xenobiotics, ubiquitous in the environment, bind to GR and are also capable of activating or repressing GR gene expression, thereby modulating GR cell and tissue-specific downstream effects in a multitude of ways that include responses to inflammatory, allergic, metabolic, neoplastic and autoimmunemore » processes. Many xenobiotics, if inadequately metabolized by xenobiotic metabolizing enzymes and not wholly eliminated, could have deleterious toxic effects with potentially lethal consequences. This review examines GR, the genomic and non-genomic actions of natural and synthetic GC and the body's handling of xenobiotic compounds, before reviewing what is presently known about GR's interactions with many of the more commonly encountered and some of the less well known GR-associated xenobiotics. GR promiscuity and crosstalk with other signaling pathways is discussed, alongside novel roles for GR that include mood disorder and addiction. A knowledge of GR interactions with xenobiotics is increasingly relevant when considering aging populations and the related prevalence of neoplastic disease, together with growing concerns around human exposure to mixtures of chemicals in the environment. Furthermore, escalating rates of obesity, Type 2 diabetes; autoimmune, allergy, addiction and mood disorder-related pathologies, require novel targeted interventions and GR appears a promising pharmacological candidate. - Highlights: • Biological impact of xenobiotics acting through Glucocorticoid Receptor. • Promiscuity of Glucocorticoid

  6. Modulation of tumor necrosis factor (TNF) receptor expression during monocytic differentiation by glucocorticoids.

    PubMed

    Goppelt-Struebe, M; Reiser, C O; Schneider, N; Grell, M

    1996-10-01

    Regulation of tumor necrosis factor receptors by glucocorticoids was investigated during phorbol ester-induced monocytic differentiation. As model system the human monocytic cell lines U937 and THP-1, which express both types of TNF receptors (TNF-R60 and TNF-R80), were differentiated with tetradecanoyl phorbol-13-acetate (TPA, 5 x 10(-9) M) in the presence or absence of dexamethasone (10(-9) - 10(-6) M). Expression of TNF receptors was determined at the mRNA level by Northern blot analysis and at the protein level by FACS analysis. During differentiation, TNF-R60 mRNA was down-regulated, whereas TNF-R80 mRNA levels were increased. Dexamethasone had no effect on TNF-R60 mRNA expression but attenuated TNF-R80 mRNA expression in both cell lines. Cell surface expression of TNF-R60 protein remained essentially unchanged during differentiation of THP-1 cells, whereas a rapid down-regulation of TNF-R80 was observed that was followed by a slow recovery. Surface expression of TNF-R80 was not affected by dexamethasone, whereas TNF-R60 expression was reduced by about 25%. These results indicate differential regulation of the two types of TNF receptors at the mRNA and protein level during monocytic differentiation. Glucocorticoids interfered with mRNA expression of TNF-R80 and protein expression of TNF-R60, but the rather limited effect leaves the question of its functional relevance open. In contrast to other cytokine systems, TNF receptors do not appear to be major targets of glucocorticoid action.

  7. Glucocorticoid receptor modulators.

    PubMed

    Meijer, Onno C; Koorneef, Lisa L; Kroon, Jan

    2018-06-01

    The glucocorticoid hormone cortisol acts throughout the body to support circadian processes and adaptation to stress. The glucocorticoid receptor is the target of cortisol and of synthetic glucocorticoids, which are used widely in the clinic. Both agonism and antagonism of the glucocorticoid receptor may be beneficial in disease, but given the wide expression of the receptor and involvement in various processes, beneficial effects are often accompanied by unwanted side effects. Selective glucocorticoid receptor modulators are ligands that induce a receptor conformation that allows activation of only a subset of downstream signaling pathways. Such molecules thereby combine agonistic and antagonistic properties. Here we discuss the mechanisms underlying selective receptor modulation and their promise in treating diseases in several organ systems where cortisol signaling plays a role. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

  8. Glucocorticoid receptor signaling in health and disease

    PubMed Central

    Kadmiel, Mahita; Cidlowski, John A.

    2013-01-01

    Glucocorticoids are steroid hormones regulated in a circadian and stres-associated manner to maintain various metabolic and homeostatic functions that are necessary for life. Synthetic glucocorticoids are widely prescribed drugs for many conditions including asthma, chronic obstructive pulmonary disease (COPD), and inflammatory disorders of the eye. Research in the last few years has begun to unravel the profound complexity of glucocorticoid signaling and has contributed remarkably to improved therapeutic strategies. Glucocorticoids signal through the glucocorticoid receptor, a member of the superfamily of nuclear receptors, in both genomic and non-genomic ways in almost every tissue in the human body. In this review, we will provide an update on glucocorticoid receptor signaling and highlight the role of GR signaling in physiological and pathophysiological conditions in the major organ systems in the human body. PMID:23953592

  9. Glucocorticoid Receptor-Mediated Repression of Pro-Inflammatory Genes in Rheumatoid Arthritis

    DTIC Science & Technology

    2015-10-01

    1 AWARD NUMBER: W81XWH-14-1-0314 TITLE: Glucocorticoid Receptor-Mediated Repression of Pro-Inflammatory Genes in Rheumatoid Arthritis ...19 Sep 2015 4. TITLE AND SUBTITLE Glucocorticoid Receptor-Mediated Repression of Pro- Inflammatory Genes in Rheumatoid Arthritis 5a. CONTRACT NUMBER...SUBJECT TERMS Rheumatoid arthritis , inflammation and autoimmunity, macrophages, glucocorticoid receptor, transcriptional regulation, coactivators and

  10. GLUCOCORTICOID RECEPTOR REGULATION IN THE RAT EMBRYO: A POTENTIAL SITE FOR DEVELOPMENTAL TOXICITY?

    EPA Science Inventory

    Glucocorticoid receptor regulation in the rat embryo: a potential site for developmental toxicity?

    Ghosh B, Wood CR, Held GA, Abbott BD, Lau C.

    National Research Council, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711, USA.

  11. Enhancement of ligand-dependent down-regulation of glucocorticoid receptor by lipopolysaccharide.

    PubMed

    Hirasawa, Noriyasu; Yashima, Kazushi; Ishihara, Kenji

    2009-10-07

    The inhibitory actions of glucocorticoids are often attenuated in inflamed tissues. The aim of the present study was to investigate whether the dexamethasone-induced downregulation of glucocorticoid receptor (GR) expression was enhanced by the stimulation with lipopolysaccharide (LPS). Various cells were stimulated with LPS (1microg/ml) for 30min and then treated with dexamethasone (1microM) for specified periods. The levels of GR and the phosphorylation at Ser211 were determined by Western blot. The effects of kinase inhibitors and a proteasome inhibitor on them were examined. The treatment of NCI-H292 cells with dexamethasone reduced the levels of GR, and the pretreatment with LPS accelerated the reduction. Such an enhancement by LPS of the dexamethasone-induced downregulation was observed in the respiratory epithelial cell lines BEAS-2B and A549, but not in the keratinocyte-like cell line HaCaT, the hematopoietic cell lines U937, THP-1 and Eol-1, or in hepatocytoma HepG2 cells. The treatment with dexamethasone and LPS apparently decreased GR levels in the lungs of BALB/c mice but not in the liver. In NCI-H292 cells, the LPS-enhanced downregulation of GR expression was recovered by the proteasome inhibitor MG-132. SP600125, SB203580 and roscovitine but not U0126 inhibited the LPS-induced enhancement of both the phosphorylation and the downregulation of GR. These findings suggested that the ligand-dependent downregulation of GR expression via the proteasome was apparent in the respiratory epithelial cells and enhanced by lipopolysaccharide via the activation of p38 MAP kinase, c-Jun N-terminal kinase and cyclin-dependent kinases.

  12. GLUCOCORTICOID RECEPTOR EXPRESSION DURING THE DEVELOPMENT OF THE EMBRYONIC MOUSE SECONDARY PALATE

    EPA Science Inventory

    Glucocorticoids are important regulators of embryonic growth and development. hese effects are mediated through glucocorticoid receptors (GR) which bind to glucocorticoid response elements upstream of regulated genes. his study examines the expression of GR and GR mRNA in embryon...

  13. Selective Glucocorticoid Receptor modulators.

    PubMed

    De Bosscher, Karolien

    2010-05-31

    The ancient two-faced Roman god Janus is often used as a metaphor to describe the characteristics of the Glucocorticoid Receptor (NR3C1), which exhibits both a beneficial side, that serves to halt inflammation, and a detrimental side responsible for undesirable effects. However, recent developments suggest that the Glucocorticoid Receptor has many more faces with the potential to express a range of different functionalities, depending on factors that include the tissue type, ligand type, receptor variants, cofactor surroundings and target gene promoters. This behavior of the receptor has made the development of safer ligands, that trigger the expression program of only a desirable subset of genes, a real challenge. Thus more knowledge-based fundamental research is needed to ensure the design and development of selective Glucocorticoid Receptor modulators capable of reaching the clinic. Recent advances in the characterization of novel selective Glucocorticoid Receptor modulators, specifically in the context of anti-inflammatory strategies, will be described in this review. 2010 Elsevier Ltd. All rights reserved.

  14. Contribution of glucocorticoids and glucocorticoid receptors to the regulation of neurodegenerative processes.

    PubMed

    Vyas, Sheela; Maatouk, Layal

    2013-12-01

    Isolation of glucocorticoids (GCs) from adrenal glands followed by synthesis led rapidly to their first clinical application, about 70 years ago, for treatment of rheumatoid arthritis. To this day GCs are used in diseases that have an inflammatory component. However, their use is carefully monitored because of harmful side effects. GCs are also synonymous with stress and adaptation. In CNS, GC binds and activates high affinity mineralocorticoid receptor (MR) and low affinity glucocorticoid receptor (GR). GR, whose expression is ubiquitous, is only activated when GC levels rise as during circadian peak and in response to stress. Numerous recent studies have yielded important and new insights on the mechanisms concerning pulsatile secretory pattern of GCs as well as various processes that tightly control their synthesis via hypothalamic-pituitary-adrenal (HPA) axis involving regulated release of corticotropin-releasing hormone (CRH) and adrenocorticotropic hormone (ACTH) from hypothalamus and pituitary, respectively. GR modulates neuronal functions and viability through both genomic and non-genomic actions, and importantly its transcriptional regulatory activity is tightly locked with GC secretory pattern. There is increasing evidence pointing to involvement of GC-GR in neurodegenerative disorders. Patients with Alzheimer's or Parkinson's or Huntington's disease show chronically high cortisol levels suggesting changes occurring in controls of HPA axis. In experimental models of these diseases, chronic stress or GC treatment was found to exacerbate both the clinical symptoms and neurodegenerative processes. However, recent evidence also shows that GC-GR can exert neuroprotective effects. Thus, for any potential therapeutic strategies in these neurodegenerative diseases we need to understand the precise modifications both in HPA axis and in GR activity and find ways to harness their protective actions.

  15. Glucocorticoid receptor-mediated induction of glutamine synthetase in skeletal muscle cells in vitro

    NASA Technical Reports Server (NTRS)

    Max, Stephen R.; Thomas, John W.; Banner, Carl; Vitkovic, Ljubisa; Konagaya, Masaaki

    1987-01-01

    The regulation by glucocorticoids of glutamine synthetase in L6 muscle cells in culture is studied. Glutamine synthetase activity was strikingly enhanced by dexamethasone. The dexamethasone-mediated induction of glutamine synthetase activity was blocked by RU38486, a glucocorticoid antagonist, indicating the involvement of intracellular glucocorticoid receptors in the induction process. RU38486 alone was without effect. Northern blot analysis revealed that dexamethasone-mediated enhancement of glutamine synthetase activity involves increased levels of glutamine synthetase mRNA. Glucocorticoids regulate the expression of glutamine synthetase mRNA in cultured muscle cells via interaction with intracellular receptors. Such regulation may be relevant to control of glutamine production by muscle.

  16. Dexamethasone and sex regulate placental glucocorticoid receptor isoforms in mice.

    PubMed

    Cuffe, James S M; Saif, Zarqa; Perkins, Anthony V; Moritz, Karen M; Clifton, Vicki L

    2017-08-01

    Maternal dexamethasone exposure in the mouse impairs placental development and programs adult disease in a sexually dimorphic manner. Glucocorticoids bind to different glucocorticoid receptor (GR) isoforms to regulate gene transcription and cellular signaling. We hypothesized that sexually dimorphic placental responses to glucocorticoids are due to differences in GR isoforms present in the placenta. Pregnant C57Bl6 mice were exposed to saline or dexamethasone from E12.5 until E14.5 (1 µg/kg/h) before the collection of placentae. Cytoplasmic and nuclear protein fractions were extracted from placentae of male and female fetuses for Western blot analysis of GR isoforms. Eight known isoforms of the GR were detected in the mouse placenta including the translational isoforms GRα-A, B, C and D1-3 and the splice variants GRA and GRP. The expression of GRA, GRP and each of the GRα isoforms were altered by dexamethasone in relation to fetal sex and cellular location. Placentae of female fetuses had higher GRα-A and GRP expression in the cytoplasm than males, and GRα-C was more highly expressed in the nucleus of females than that in males. Dexamethasone significantly increased the cytoplasmic expression of GRα-A, but reduced the expression of GRα-C in placentae of males. Dexamethasone increased the expression of the GRα-C-regulated genes Sgk1 and Bcl2l11 , particularly in females. The cleaved caspase-3 staining in placental sections indicated GRα-C may mediate sex differences in dexamethasone-induced apoptosis. These findings may underlie the sex-specific placental adaptations that regulate different growth profiles in males and females and different risks for programmed disease outcomes in offspring. © 2017 Society for Endocrinology.

  17. Cancer cell-selective promoter recognition accompanies antitumor effect by glucocorticoid receptor-targeted gold nanoparticle

    NASA Astrophysics Data System (ADS)

    Sau, Samaresh; Agarwalla, Pritha; Mukherjee, Sudip; Bag, Indira; Sreedhar, Bojja; Pal-Bhadra, Manika; Patra, Chitta Ranjan; Banerjee, Rajkumar

    2014-05-01

    Nanoparticles, such as gold nanoparticles (GNP), upon convenient modifications perform multi tasks catering to many biomedical applications. However, GNP or any other type of nanoparticles is yet to achieve the feat of intracellular regulation of endogenous genes of choice such as through manipulation of a gene-promoter in a chromosome. As for gene modulation and delivery, GNP (or other nanoparticles) showed only limited gene therapy potential, which relied on the delivery of `exogenous' genes invoking gene knockdown or replacement. Practically, there are no instances for the nanoparticle-mediated promoter regulation of `endogenous' genes, more so, as a cancer selective phenomenon. In this regard, we report the development of a simple, easily modifiable GNP-formulation, which promoted/up-regulated the expression of a specific category of `endogenous' genes, the glucocorticoid responsive genes. This genetic up-regulation was induced in only cancer cells by modified GNP-mediated transcriptional activation of its cytoplasmic receptor, glucocorticoid receptor (GR). Normal cells and their GR remained primarily unperturbed by this GNP-formulation. The most potent gene up-regulating GNP-formulation down-regulated a cancer-specific proliferative signal, phospho-Akt in cancer cells, which accompanied retardation of tumor growth in the murine melanoma model. We show that GR-targeted GNPs may find potential use in the targeting and modulation of genetic information in cancer towards developing novel anticancer therapeutics.Nanoparticles, such as gold nanoparticles (GNP), upon convenient modifications perform multi tasks catering to many biomedical applications. However, GNP or any other type of nanoparticles is yet to achieve the feat of intracellular regulation of endogenous genes of choice such as through manipulation of a gene-promoter in a chromosome. As for gene modulation and delivery, GNP (or other nanoparticles) showed only limited gene therapy potential, which relied

  18. MicroRNA-433 Dampens Glucocorticoid Receptor Signaling, Impacting Circadian Rhythm and Osteoblastic Gene Expression*

    PubMed Central

    Smith, Spenser S.; Dole, Neha S.; Franceschetti, Tiziana; Hrdlicka, Henry C.; Delany, Anne M.

    2016-01-01

    Serum glucocorticoids play a critical role in synchronizing circadian rhythm in peripheral tissues, and multiple mechanisms regulate tissue sensitivity to glucocorticoids. In the skeleton, circadian rhythm helps coordinate bone formation and resorption. Circadian rhythm is regulated through transcriptional and post-transcriptional feedback loops that include microRNAs. How microRNAs regulate circadian rhythm in bone is unexplored. We show that in mouse calvaria, miR-433 displays robust circadian rhythm, peaking just after dark. In C3H/10T1/2 cells synchronized with a pulse of dexamethasone, inhibition of miR-433 using a tough decoy altered the period and amplitude of Per2 gene expression, suggesting that miR-433 regulates rhythm. Although miR-433 does not directly target the Per2 3′-UTR, it does target two rhythmically expressed genes in calvaria, Igf1 and Hif1α. miR-433 can target the glucocorticoid receptor; however, glucocorticoid receptor protein abundance was unaffected in miR-433 decoy cells. Rather, miR-433 inhibition dramatically enhanced glucocorticoid signaling due to increased nuclear receptor translocation, activating glucocorticoid receptor transcriptional targets. Last, in calvaria of transgenic mice expressing a miR-433 decoy in osteoblastic cells (Col3.6 promoter), the amplitude of Per2 and Bmal1 mRNA rhythm was increased, confirming that miR-433 regulates circadian rhythm. miR-433 was previously shown to target Runx2, and mRNA for Runx2 and its downstream target, osteocalcin, were also increased in miR-433 decoy mouse calvaria. We hypothesize that miR-433 helps maintain circadian rhythm in osteoblasts by regulating sensitivity to glucocorticoid receptor signaling. PMID:27551048

  19. MicroRNA-433 Dampens Glucocorticoid Receptor Signaling, Impacting Circadian Rhythm and Osteoblastic Gene Expression.

    PubMed

    Smith, Spenser S; Dole, Neha S; Franceschetti, Tiziana; Hrdlicka, Henry C; Delany, Anne M

    2016-10-07

    Serum glucocorticoids play a critical role in synchronizing circadian rhythm in peripheral tissues, and multiple mechanisms regulate tissue sensitivity to glucocorticoids. In the skeleton, circadian rhythm helps coordinate bone formation and resorption. Circadian rhythm is regulated through transcriptional and post-transcriptional feedback loops that include microRNAs. How microRNAs regulate circadian rhythm in bone is unexplored. We show that in mouse calvaria, miR-433 displays robust circadian rhythm, peaking just after dark. In C3H/10T1/2 cells synchronized with a pulse of dexamethasone, inhibition of miR-433 using a tough decoy altered the period and amplitude of Per2 gene expression, suggesting that miR-433 regulates rhythm. Although miR-433 does not directly target the Per2 3'-UTR, it does target two rhythmically expressed genes in calvaria, Igf1 and Hif1α. miR-433 can target the glucocorticoid receptor; however, glucocorticoid receptor protein abundance was unaffected in miR-433 decoy cells. Rather, miR-433 inhibition dramatically enhanced glucocorticoid signaling due to increased nuclear receptor translocation, activating glucocorticoid receptor transcriptional targets. Last, in calvaria of transgenic mice expressing a miR-433 decoy in osteoblastic cells (Col3.6 promoter), the amplitude of Per2 and Bmal1 mRNA rhythm was increased, confirming that miR-433 regulates circadian rhythm. miR-433 was previously shown to target Runx2, and mRNA for Runx2 and its downstream target, osteocalcin, were also increased in miR-433 decoy mouse calvaria. We hypothesize that miR-433 helps maintain circadian rhythm in osteoblasts by regulating sensitivity to glucocorticoid receptor signaling. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

  20. The aryl hydrocarbon receptor and glucocorticoid receptor interact to activate human metallothionein 2A

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Sato, Shoko, E-mail: satosho@rs.tus.ac.jp; Shirakawa, Hitoshi, E-mail: shirakah@m.tohoku.ac.jp; Tomita, Shuhei, E-mail: tomita@med.tottori-u.ac.jp

    2013-11-15

    Although the aryl hydrocarbon receptor (AHR) and glucocorticoid receptor (GR) play essential roles in mammalian development, stress responses, and other physiological events, crosstalk between these receptors has been the subject of much debate. Metallothioneins are classic glucocorticoid-inducible genes that were reported to increase upon treatment with AHR agonists in rodent tissues and cultured human cells. In this study, the mechanism of human metallothionein 2A (MT2A) gene transcription activation by AHR was investigated. Cotreatment with 3-methylcholanthrene and dexamethasone, agonists of AHR and GR respectively, synergistically increased MT2A mRNA levels in HepG2 cells. MT2A induction was suppressed by RNA interference against AHRmore » or GR. Coimmunoprecipitation experiments revealed a physical interaction between AHR and GR proteins. Moreover, chromatin immunoprecipitation assays indicated that AHR was recruited to the glucocorticoid response element in the MT2A promoter. Thus, we provide a novel mechanism whereby AHR modulates expression of human MT2A via the glucocorticoid response element and protein–protein interactions with GR. - Highlights: • Aryl hydrocarbon receptor forms a complex with glucocorticoid receptor in cells. • Human metallothionein gene is regulated by the AHR and GR interaction. • AHR–GR complex binds to glucocorticoid response element in metallothionein gene. • We demonstrated a novel transcriptional mechanism via AHR and GR interaction.« less

  1. From receptor balance to rational glucocorticoid therapy.

    PubMed

    de Kloet, E Ron

    2014-08-01

    Corticosteroids secreted as end product of the hypothalamic-pituitary-adrenal axis act like a double-edged sword in the brain. The hormones coordinate appraisal processes and decision making during the initial phase of a stressful experience and promote subsequently cognitive performance underlying the management of stress adaptation. This action exerted by the steroids on the initiation and termination of the stress response is mediated by 2 related receptor systems: mineralocorticoid receptors (MRs) and glucocorticoid receptors (GRs). The receptor types are unevenly distributed but colocalized in abundance in neurons of the limbic brain to enable these complementary hormone actions. This contribution starts from a historical perspective with the observation that phasic occupancy of GR during ultradian rhythmicity is needed to maintain responsiveness to corticosteroids. Then, during stress, initially MR activation enhances excitability of limbic networks that are engaged in appraisal and emotion regulation. Next, the rising hormone concentration occupies GR, resulting in reallocation of energy to limbic-cortical circuits with a role in behavioral adaptation and memory storage. Upon MR:GR imbalance, dysregulation of the hypothalamic-pituitary-adrenal axis occurs, which can enhance an individual's vulnerability. Imbalance is characteristic for chronic stress experience and depression but also occurs during exposure to synthetic glucocorticoids. Hence, glucocorticoid psychopathology may develop in susceptible individuals because of suppression of ultradian/circadian rhythmicity and depletion of endogenous corticosterone from brain MR. This knowledge generated from testing the balance hypothesis can be translated to a rational glucocorticoid therapy.

  2. α Actinin 4 (ACTN4) Regulates Glucocorticoid Receptor-mediated Transactivation and Transrepression in Podocytes*

    PubMed Central

    Zhao, Xuan; Khurana, Simran; Charkraborty, Sharmistha; Tian, Yuqian; Sedor, John R.; Bruggman, Leslie A.; Kao, Hung-Ying

    2017-01-01

    Glucocorticoids are a general class of steroids that possess renoprotective activity in glomeruli through their interaction with the glucocorticoid receptor. However, the mechanisms by which glucocorticoids ameliorate proteinuria and glomerular disease are not well understood. In this study, we demonstrated that α actinin 4 (ACTN4), an actin-cross-linking protein known to coordinate cytoskeletal organization, interacts with the glucocorticoid receptor (GR) in the nucleus of human podocytes (HPCs), a key cell type in the glomerulus critical for kidney filtration function. The GR-ACTN4 complex enhances glucocorticoid response element (GRE)-driven reporter activity. Stable knockdown of ACTN4 by shRNA in HPCs significantly reduces dexamethasone-mediated induction of GR target genes and GRE-driven reporter activity without disrupting dexamethasone-induced nuclear translocation of GR. Synonymous mutations or protein expression losses in ACTN4 are associated with kidney diseases, including focal segmental glomerulosclerosis, characterized by proteinuria and podocyte injury. We found that focal segmental glomerulosclerosis-linked ACTN4 mutants lose their ability to bind liganded GR and support GRE-mediated transcriptional activity. Mechanistically, GR and ACTN4 interact in the nucleus of HPCs. Furthermore, disruption of the LXXLL nuclear receptor-interacting motif present in ACTN4 results in reduced GR interaction and dexamethasone-mediated transactivation of a GRE reporter while still maintaining its actin-binding activity. In contrast, an ACTN4 isoform, ACTN4 (Iso), that loses its actin-binding domain is still capable of potentiating a GRE reporter. Dexamethasone induces the recruitment of ACTN4 and GR to putative GREs in dexamethasone-transactivated promoters, SERPINE1, ANGPLT4, CCL20, and SAA1 as well as the NF-κB (p65) binding sites on GR-transrepressed promoters such as IL-1β, IL-6, and IL-8. Taken together, our data establish ACTN4 as a transcriptional co-regulator

  3. Glucocorticoid Receptor Interacting Co-regulators: Putative Candidates for Future Drug Targeting Therapy.

    PubMed

    Di Silvestre, Alessia; Lucafo, Marianna; De Iudicibus, Sara; Ventura, Alessandro; Martelossi, Stefano; Stocco, Gabriele; Decorti, Giuliana

    2017-01-01

    Glucocorticoids (GCs) are largely used in different inflammatory, autoimmune and proliferative diseases. To date their mechanism of action is not completely clear and more studies are necessary, in particular to explain the great interindividual variability in clinical response. In this panorama the glucocorticoid receptor (GR) has an important role: in fact it regulates the pharmacological response thanks to the capability to interact with different molecules (DNA, RNA, ncRNA and proteins) that are known to influence its activity. In this review our aim is to highlight the knowledge about the role of protein-protein, RNAprotein interactions and epigenetic modifications on the GR and the consequent response to GCs. The characteristics of these interactions with the GR and their effects on the pharmacological activity of GCs will be examined. This information could contribute to the prediction of individual sensitivity to steroids through the identification of new markers of GC resistance. In addition this knowledge may be used in developing new strategies for targeted therapy. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  4. Glucocorticoid activity detected by in vivo zebrafish assay and in vitro glucocorticoid receptor bioassay at environmental relevant concentrations.

    PubMed

    Chen, Qiyu; Jia, Ai; Snyder, Shane A; Gong, Zhiyuan; Lam, Siew Hong

    2016-02-01

    Glucocorticoids are pharmaceutical contaminants of emerging concern due to their incomplete removal during wastewater treatment, increased presence in aquatic environment and their biological potency. The zebrafish is a popular model for aquatic toxicology and environmental risk assessment. This study aimed to determine if glucocorticoids at environmental concentrations would perturb expression of selected glucocorticoid-responsive genes in zebrafish and to investigate their potentials as an in vivo zebrafish assay in complementing in vitro glucocorticoid receptor bioassay. The relative expression of eleven glucocorticoid-responsive genes in zebrafish larvae and liver of adult male zebrafish exposed to three representative glucocorticoids (dexamethasone, prednisolone and triamcinolone) was determined. The expression of pepck, baiap2 and pxr was up-regulated in zebrafish larvae and the expression of baiap2, pxr and mmp-2 was up-regulated in adult zebrafish exposed to glucocorticoids at concentrations equivalent to total glucocorticoids reported in environmental samples. The responsiveness of the specific genes were sufficiently robust in zebrafish larvae exposed to a complex environmental sample detected with in vitro glucocorticoid activity equivalent to 478 pM dexamethasone (DEX-EQ) and confirmed to contain low concentration (0.2 ng/L or less) of the targeted glucocorticoids, and possibly other glucocorticoid-active compounds. The findings provided in vivo relevance to the in vitro glucocorticoid activity and suggested that the environmental sample can perturb glucocorticoid-responsive genes in its original, or half the diluted, concentration as may be found in the environment. The study demonstrated the important complementary roles of in vivo zebrafish and in vitro bioassays coupled with analytical chemistry in monitoring environmental glucocorticoid contaminants. Copyright © 2015 Elsevier Ltd. All rights reserved.

  5. Glucocorticoid receptors in the prefrontal cortex regulate stress-evoked dopamine efflux and aspects of executive function.

    PubMed

    Butts, Kelly A; Weinberg, Joanne; Young, Allan H; Phillips, Anthony G

    2011-11-08

    Enhanced dopamine efflux in the prefrontal cortex is a well-documented response to acute stress. However, the underlying mechanism(s) for this response is unknown. Using in vivo microdialysis, we demonstrate that blocking glucocorticoid receptors locally within the rat prefrontal cortex results in a reduction in stress-evoked dopamine efflux. In contrast, blocking glucocorticoid receptors in the ventral tegmental area did not affect stress-evoked dopamine efflux in the prefrontal cortex. Additionally, local administration of corticosterone into the prefrontal cortex increased prefrontal dopamine efflux. The functional impact of enhanced dopamine efflux evoked by acute stress was demonstrated using a cognitive task dependent on the prefrontal cortex and sensitive to impairment in working memory. Notably, stress-induced impairments in cognition were attenuated by blockade of glucocorticoid receptors in the prefrontal cortex. Taken together, these data demonstrate that glucocorticoids act locally within the prefrontal cortex to modulate mesocortical dopamine efflux leading to the cognitive impairments observed during acute stress.

  6. Control of energy balance by hypothalamic gene circuitry involving two nuclear receptors, neuron-derived orphan receptor 1 and glucocorticoid receptor.

    PubMed

    Kim, Sun-Gyun; Lee, Bora; Kim, Dae-Hwan; Kim, Juhee; Lee, Seunghee; Lee, Soo-Kyung; Lee, Jae W

    2013-10-01

    Nuclear receptors (NRs) regulate diverse physiological processes, including the central nervous system control of energy balance. However, the molecular mechanisms for the central actions of NRs in energy balance remain relatively poorly defined. Here we report a hypothalamic gene network involving two NRs, neuron-derived orphan receptor 1 (NOR1) and glucocorticoid receptor (GR), which directs the regulated expression of orexigenic neuropeptides agouti-related peptide (AgRP) and neuropeptide Y (NPY) in response to peripheral signals. Our results suggest that the anorexigenic signal leptin induces NOR1 expression likely via the transcription factor cyclic AMP response element-binding protein (CREB), while the orexigenic signal glucocorticoid mobilizes GR to inhibit NOR1 expression by antagonizing the action of CREB. Also, NOR1 suppresses glucocorticoid-dependent expression of AgRP and NPY. Consistently, relative to wild-type mice, NOR1-null mice showed significantly higher levels of AgRP and NPY and were less responsive to leptin in decreasing the expression of AgRP and NPY. These results identify mutual antagonism between NOR1 and GR to be a key rheostat for peripheral metabolic signals to centrally control energy balance.

  7. Metformin suppresses CYP1A1 and CYP1B1 expression in breast cancer cells by down-regulating aryl hydrocarbon receptor expression

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Do, Minh Truong; Kim, Hyung Gyun; Tran, Thi Thu Phuong

    2014-10-01

    Induction of cytochrome P450 (CYP) 1A1 and CYP1B1 by environmental xenobiotic chemicals or endogenous ligands through the activation of the aryl hydrocarbon receptor (AhR) has been implicated in a variety of cellular processes related to cancer, such as transformation and tumorigenesis. Here, we investigated the effects of the anti-diabetes drug metformin on expression of CYP1A1 and CYP1B1 in breast cancer cells under constitutive and inducible conditions. Our results indicated that metformin down-regulated the expression of CYP1A1 and CYP1B1 in breast cancer cells under constitutive and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-induced conditions. Down-regulation of AhR expression was required for metformin-mediated decreases in CYP1A1 andmore » CYP1B1 expression, and the metformin-mediated CYP1A1 and CYP1B1 reduction is irrelevant to estrogen receptor α (ERα) signaling. Furthermore, we found that metformin markedly down-regulated Sp1 protein levels in breast cancer cells. The use of genetic and pharmacological tools revealed that metformin-mediated down-regulation of AhR expression was mediated through the reduction of Sp1 protein. Metformin inhibited endogenous AhR ligand-induced CYP1A1 and CYP1B1 expression by suppressing tryptophan-2,3-dioxygenase (TDO) expression in MCF-7 cells. Finally, metformin inhibits TDO expression through a down-regulation of Sp1 and glucocorticoid receptor (GR) protein levels. Our findings demonstrate that metformin reduces CYP1A1 and CYP1B1 expression in breast cancer cells by down-regulating AhR signaling. Metformin would be able to act as a potential chemopreventive agent against CYP1A1 and CYP1B1-mediated carcinogenesis and development of cancer. - Graphical abstract: Schematic of the CYP1A1 and CYP1B1 gene regulation by metformin. - Highlights: • Metformin inhibits CYP1A1 and CYP1B1 expression. • Metformin down-regulates the AhR signaling. • Metformin reduces Sp1 protein expression. • Metformin suppresses TDO

  8. 5-Functionalized indazoles as glucocorticoid receptor agonists.

    PubMed

    Bai, Mei; Carr, Grant; Deorazio, Russell J; Friedrich, Thomas D; Dobritsa, Svetlana; Fitzpatrick, Kevin; Guzzo, Peter R; Kitchen, Douglas B; Lynch, Michael A; Peace, Denise; Sajad, Mohammed; Usyatinsky, Alexander; Wolf, Mark A

    2010-05-15

    An indazole based series of glucocorticoid receptor agonists is reported. The SAR exploration of this scaffold yielded compounds with nanomolar affinity for the glucocorticoid receptor with indications of selectivity for the preferred transrepression mechanism; in vivo efficacy was observed in the mouse LPS induced TNFalpha model for compound 28. Copyright 2010 Elsevier Ltd. All rights reserved.

  9. Glucocorticoid dexamethasone down-regulates basal and vitamin D3 induced cathelicidin expression in human monocytes and bronchial epithelial cell line.

    PubMed

    Kulkarni, Nikhil Nitin; Gunnarsson, Hörður Ingi; Yi, Zhiqian; Gudmundsdottir, Steinunn; Sigurjonsson, Olafur E; Agerberth, Birgitta; Gudmundsson, Gudmundur H

    2016-02-01

    Glucocorticoids (GCs) have been extensively used as the mainstream treatment for chronic inflammatory disorders. The persistent use of steroids in the past decades and the association with secondary infections warrants for detailed investigation into their effects on the innate immune system and the therapeutic outcome. In this study, we analyse the effect of GCs on antimicrobial polypeptide (AMP) expression. We hypothesize that GC related side effects, including secondary infections are a result of compromised innate immune responses. Here, we show that treatment with dexamethasone (Dex) inhibits basal mRNA expression of the following AMPs; human cathelicidin, human beta defensin 1, lysozyme and secretory leukocyte peptidase 1 in the THP-1 monocytic cell-line (THP-1 monocytes). Furthermore, pre-treatment with Dex inhibits vitamin D3 induced cathelicidin expression in THP-1 monocytes, primary monocytes and in the human bronchial epithelial cell line BCi NS 1.1. We also demonstrate that treatment with the glucocorticoid receptor (GR) inhibitor RU486 counteracts Dex mediated down-regulation of basal and vitamin D3 induced cathelicidin expression in THP-1 monocytes. Moreover, we confirmed the anti-inflammatory effect of Dex. Pre-treatment with Dex inhibits dsRNA mimic poly IC induction of the inflammatory chemokine IP10 (CXCL10) and cytokine IL1B mRNA expression in THP-1 monocytes. These results suggest that GCs inhibit innate immune responses, in addition to exerting beneficial anti-inflammatory effects. Copyright © 2015 Elsevier GmbH. All rights reserved.

  10. Molecular regulation of urea cycle function by the liver glucocorticoid receptor.

    PubMed

    Okun, Jürgen G; Conway, Sean; Schmidt, Kathrin V; Schumacher, Jonas; Wang, Xiaoyue; de Guia, Roldan; Zota, Annika; Klement, Johanna; Seibert, Oksana; Peters, Achim; Maida, Adriano; Herzig, Stephan; Rose, Adam J

    2015-10-01

    One of the major side effects of glucocorticoid (GC) treatment is lean tissue wasting, indicating a prominent role in systemic amino acid metabolism. In order to uncover a novel aspect of GCs and their intracellular-receptor, the glucocorticoid receptor (GR), on metabolic control, we conducted amino acid and acylcarnitine profiling in human and mouse models of GC/GR gain- and loss-of-function. Blood serum and tissue metabolite levels were determined in Human Addison's disease (AD) patients as well as in mouse models of systemic and liver-specific GR loss-of-function (AAV-miR-GR) with or without dexamethasone (DEX) treatments. Body composition and neuromuscular and metabolic function tests were conducted in vivo and ex vivo, the latter using precision cut liver slices. A serum metabolite signature of impaired urea cycle function (i.e. higher [ARG]:[ORN + CIT]) was observed in human (CTRL: 0.45 ± 0.03, AD: 1.29 ± 0.04; p < 0.001) and mouse (AAV-miR-NC: 0.97 ± 0.13, AAV-miR-GR: 2.20 ± 0.19; p < 0.001) GC/GR loss-of-function, with similar patterns also observed in liver. Serum urea levels were consistently affected by GC/GR gain- (∼+32%) and loss (∼-30%) -of-function. Combined liver-specific GR loss-of-function with DEX treatment revealed a tissue-autonomous role for the GR to coordinate an upregulation of liver urea production rate in vivo and ex vivo, and prevent hyperammonaemia and associated neuromuscular dysfunction in vivo. Liver mRNA expression profiling and GR-cistrome mining identified Arginase I (ARG1) a urea cycle gene targeted by the liver GR. The liver GR controls systemic and liver urea cycle function by transcriptional regulation of ARG1 expression.

  11. Novel regulation of 25-hydroxyvitamin D3 24-hydroxylase (24(OH)ase) transcription by glucocorticoids: cooperative effects of the glucocorticoid receptor, C/EBP beta, and the Vitamin D receptor in 24(OH)ase transcription.

    PubMed

    Dhawan, Puneet; Christakos, Sylvia

    2010-08-15

    Glucocorticoid-induced bone loss has been proposed to involve direct effects on bone cells as well as alterations in calcium absorption and excretion. Since vitamin D is important for the maintenance of calcium homeostasis, in the present study the effects of glucocorticoids on vitamin D metabolism through the expression of 24(OH)ase, an enzyme involved in the catabolism of 1,25(OH)(2)D(3), were examined. Injection of vitamin D replete mice with dexamethasone (dex) resulted in a significant induction in 24(OH)ase mRNA in kidney, indicating a regulatory effect of glucocorticoids on vitamin D metabolism. Whether glucocorticoids can affect 24(OH)ase transcription is not known. Here we demonstrate for the first time a glucocorticoid receptor (GR) dependent enhancement of 1,25(OH)(2)D(3)-induced 24(OH)ase transcription. Dex treatment of GR and vitamin D receptor (VDR) transfected COS-7 cells and dex treatment of osteoblastic cells (in which VDR and GR are present endogenously) potentiated 1,25(OH)(2)D(3)-induced 24(OH)ase transcription. In addition, GR was found to cooperate with C/EBP beta to enhance VDR-mediated 24(OH)ase transcription. Using the rat 24(OH)ase promoter with the C/EBP site mutated, GR-mediated potentiation of 1,25(OH)(2)D(3)-induced 24(OH)ase transcription was inhibited. Immunoprecipitation indicated that that GR can interact with C/EBP beta and ChIP/re-ChIP analysis showed that C/EBP beta and GR bind simultaneously to the 24(OH)ase promoter. These findings indicate a novel mechanism whereby glucocorticoids can alter VDR-mediated 24(OH)ase transcription through functional cooperation between C/EBP beta and GR that results in an enhanced ability of C/EBP beta to cooperate with VDR in the regulation of 24(OH)ase. (c) 2010 Wiley-Liss, Inc.

  12. BDNF and glucocorticoids regulate corticotrophin-releasing hormone (CRH) homeostasis in the hypothalamus.

    PubMed

    Jeanneteau, Freddy D; Lambert, W Marcus; Ismaili, Naima; Bath, Kevin G; Lee, Francis S; Garabedian, Michael J; Chao, Moses V

    2012-01-24

    Regulation of the hypothalamic-pituitary-adrenal (HPA) axis is critical for adaptation to environmental changes. The principle regulator of the HPA axis is corticotrophin-releasing hormone (CRH), which is made in the parventricular nucleus and is an important target of negative feedback by glucocorticoids. However, the molecular mechanisms that regulate CRH are not fully understood. Disruption of normal HPA axis activity is a major risk factor of neuropsychiatric disorders in which decreased expression of the glucocorticoid receptor (GR) has been documented. To investigate the role of the GR in CRH neurons, we have targeted the deletion of the GR, specifically in the parventricular nucleus. Impairment of GR function in the parventricular nucleus resulted in an enhancement of CRH expression and an up-regulation of hypothalamic levels of BDNF and disinhibition of the HPA axis. BDNF is a stress and activity-dependent factor involved in many activities modulated by the HPA axis. Significantly, ectopic expression of BDNF in vivo increased CRH, whereas reduced expression of BDNF, or its receptor TrkB, decreased CRH expression and normal HPA functions. We find the differential regulation of CRH relies upon the cAMP response-element binding protein coactivator CRTC2, which serves as a switch for BDNF and glucocorticoids to direct the expression of CRH.

  13. Receptor-dependent mechanisms of glucocorticoid and dioxin-induced cleft palate

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Pratt, R.M.

    1985-09-01

    Glucocorticoids (triamcinolone) and dioxins (TCDD) are highly specific teratogens in the mouse, in that cleft palate is the major malformation observed. Glucocorticoids and TCDD both readily cross the yolk sac and placenta and appear in the developing secondary palate. Structure-activity relationships for glucocorticoid- and TCDD-induced cleft palate suggest a receptor involvement. Receptors for glucocorticoids and TCDD are present in the palate and their levels in various mouse strains are highly correlated with their sensitivity to cleft palate induction. Receptors for glucocorticoids appear to be more prevalent in the palatal mesenchymal cells whereas those for TCDD are probably located in themore » palatal epithelial cells. Glucocorticoids exert their teratogenic effect on the palate by inhibiting the growth of the palatal mesenchymal cells whereas TCDD alters the terminal cell differentiation of the media palatal epithelial cells. 71 references.« less

  14. The Endocrine Disrupting Chemical Tolylfluanid Alters Adipocyte Metabolism via Glucocorticoid Receptor Activation

    PubMed Central

    Neel, Brian A.; Brady, Matthew J.

    2013-01-01

    Glucocorticoid signaling plays a critical role in regulating energy metabolism. Emerging data implicate environmental endocrine-disrupting chemicals as contributors to the obesity and diabetes epidemics. Previous studies have shown that the phenylsulfamide fungicide tolylfluanid (TF) augments glucocorticoid receptor (GR)-dependent luciferase expression in 3T3-L1 preadipocytes while modulating insulin action in primary murine and human adipocytes. Studies were performed to interrogate glucocorticoid signaling in primary adipocytes exposed to TF. TF mimicked the gene transcription profile of the murine glucocorticoid corticosterone (Cort). Cellular fractionation assays demonstrated that TF treatment promoted the activating serine phosphorylation of GR, augmenting its cytoplasmic-to-nuclear translocation as well as its enrichment at glucocorticoid response elements on the glucocorticoid-induced leucine zipper gene promoter. After acute treatment, Cort or TF promoted insulin receptor substrate-1 (IRS-1) gene and protein expression. Either treatment also enriched GR binding at an identified glucocorticoid response element in the IRS-1 gene. TF or Cort each increased insulin-stimulated lipogenesis, an effect resulting from increased lipogenic gene expression and enhanced insulin-stimulated dephosphorylation of acetyl-coenzyme A carboxylase. The augmentation of insulin-stimulated lipogenesis was mediated through a specific enhancement of Akt phosphorylation at T308. These findings support modulation of IRS-1 levels as a mechanism for glucocorticoid-mediated changes in insulin action in primary adipocytes. Albeit with less affinity than Cort, in silico analysis suggests that TF can interact with the ligand binding pocket of GR. Collectively, these studies identify TF as a structurally unique environmental glucocorticoid. Glucocorticoid signaling may thus represent a novel pathway by which environmental toxicants promote the development of metabolic diseases. PMID:23340252

  15. Glucocorticoid-induced TNF receptor family-related protein ligand regulates the migration of monocytes to the inflamed intestine

    PubMed Central

    Liao, Gongxian; van Driel, Boaz; Magelky, Erica; O'Keeffe, Michael S.; de Waal Malefyt, Rene; Engel, Pablo; Herzog, Roland W.; Mizoguchi, Emiko; Bhan, Atul K.; Terhorst, Cox

    2014-01-01

    Glucocorticoid-induced TNF receptor family-related protein (GITR) regulates the function of both T cells and antigen-presenting cells (APCs), while the function of GITR ligand (GITR-L) is largely unknown. Here we evaluate the role of GITR-L, whose expression is restricted to APCs, in the development of enterocolitis. On injecting naive CD4+ T cells, GITR-L−/−Rag−/− mice develop a markedly milder colitis than Rag−/− mice, which correlates with a 50% reduction of Ly6C+CD11b+MHCII+ macrophages in the lamina propria and mesenteric lymph nodes. The same result was observed in αCD40-induced acute colitis and during peritonitis, suggesting an altered monocyte migration. In line with these observations, the number of nondifferentiated monocytes was approximately 3-fold higher in the spleen of GITR-L−/−Rag−/− mice than in Rag−/− mice after αCD40 induction. Consistent with the dynamic change in the formation of an active angiotensin II type 1 receptor (AT1) dimer in GITR-L−/− splenic monocytes during intestinal inflammation, the migratory capability of splenic monocytes from GITR-L-deficient mice was impaired in an in vitro transwell migration assay. Conversely, αGITR-L reduces the number of splenic Ly6Chi monocytes, concomitantly with an increase in AT1 dimers. We conclude that GITR-L regulates the number of proinflammatory macrophages in sites of inflammation by controlling the egress of monocytes from the splenic reservoir.—Liao, G., van Driel, B., Magelky, E., O'Keeffe, M. S., de Waal Malefyt, R., Engel, P., Herzog, R. W., Mizoguchi, E., Bhan, A. K., Terhorst, C. Glucocorticoid-induced TNF receptor family-related protein ligand regulates the migration of monocytes to the inflamed intestine. PMID:24107315

  16. The antidepressant fluoxetine normalizes the nuclear glucocorticoid receptor evoked by psychosocial stress

    NASA Astrophysics Data System (ADS)

    Mitić, M.; Simić, I.; Djordjević, J.; Radojčić, M. B.; Adžić, M.

    2011-12-01

    Dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis has been implicated in the pathophysiology of depression and stress disorders. Glucocorticoids, key regulators of the stress response, exert diverse effects on cellular processes in the hippocampus. Beside non-genomic pathways, glucocorticoid effects are mediated through activation of the glucocorticoid receptor (GR), a ligand activated transcriptional factor that belongs to the nuclear hormone receptor superfamily. We analysed the GR protein levels both in the cytoplasmic and nuclear compartments of the hippocampus of Wistar rats exposed to chronic psychosocial isolation stress upon chronic fluoxetine (FLU) treatment. Under chronic stress, corticosterone levels (CORT) were decreased compared to the control, and treatment with FLU did not change its level in the stressed rats. At the molecular level, FLU normalized the level of nuclear GR protein in the hippocampus of the stressed rats. Discrepancy between normalization of nuclear GR in the hippocampus and lack of normalization of HPA axis activity judged by CORT, suggests that other brain structures such as the amygdale and prefrontal cortex that also regulate HPA axis activity, seem not to be normalized by the FLU treatment used in our study.

  17. Selective glucocorticoid receptor modulator compound A, in contrast to prednisolone, does not induce leptin or the leptin receptor in human osteoarthritis synovial fibroblasts.

    PubMed

    Malaise, Olivier; Relic, Biserka; Quesada-Calvo, Florence; Charlier, Edith; Zeddou, Mustapha; Neuville, Sophie; Gillet, Philippe; Louis, Edouard; de Seny, Dominique; Malaise, Michel G

    2015-06-01

    Glucocorticoids are powerful anti-inflammatory compounds that also induce the expression of leptin and leptin receptor (Ob-R) in synovial fibroblasts through TGF-βsignalling and Smad1/5 phosphorylation. Compound A (CpdA), a selective glucocorticoid receptor agonist, reduces inflammation in murine arthritis models and does not induce diabetes or osteoporosis, thus offering an improved risk:benefit ratio in comparison with glucocorticoids. Due to the detrimental role of leptin in OA pathogenesis, we sought to determine whether CpdA also induced leptin and Ob-R protein expression as observed with prednisolone. Human synovial fibroblasts and chondrocytes were isolated from the synovium and cartilage of OA patients after joint surgery. The cells were treated with prednisolone, TGF-β1, TNF-α and/or CpdA. Levels of leptin, IL-6, IL-8, MMP-1 and MMP-3 were measured by ELISA and expression levels of Ob-R phospho-Smad1/5, phospho-Smad2, α-tubulin and glyceraldehyde 3-phosphate dehydrogenase were analysed by western blotting. CpdA, unlike prednisolone, did not induce leptin secretion or Ob-R protein expression in OA synovial fibroblasts. Moreover, CpdA decreased endogenous Ob-R expression and down-regulated prednisolone-induced leptin secretion and Ob-R expression. Mechanistically, CpdA, unlike prednisolone, did not induce Smad1/5 phosphorylation. CpdA, similarly to prednisolone, down-regulated endogenous and TNF-α-induced IL-6, IL-8, MMP-1 and MMP-3 protein secretion. The dissociative effect of CpdA was confirmed using chondrocytes with no induction of leptin secretion, but with a significant decrease in IL-6, IL-8, MMP-1 and MMP-3 protein secretion. CpdA, unlike prednisolone, did not induce leptin or Ob-R in human OA synovial fibroblasts, thereby demonstrating an improved risk:benefit ratio. © The Author 2014. Published by Oxford University Press on behalf of the British Society for Rheumatology. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  18. Dibutyltin Disrupts Glucocorticoid Receptor Function and Impairs Glucocorticoid-Induced Suppression of Cytokine Production

    PubMed Central

    Gumy, Christel; Chandsawangbhuwana, Charlie; Dzyakanchuk, Anna A.; Kratschmar, Denise V.; Baker, Michael E.; Odermatt, Alex

    2008-01-01

    Background Organotins are highly toxic and widely distributed environmental chemicals. Dibutyltin (DBT) is used as stabilizer in the production of polyvinyl chloride plastics, and it is also the major metabolite formed from tributyltin (TBT) in vivo. DBT is immunotoxic, however, the responsible targets remain to be defined. Due to the importance of glucocorticoids in immune-modulation, we investigated whether DBT could interfere with glucocorticoid receptor (GR) function. Methodology We used HEK-293 cells transiently transfected with human GR as well as rat H4IIE hepatoma cells and native human macrophages and human THP-1 macrophages expressing endogenous receptor to study organotin effects on GR function. Docking of organotins was used to investigate the binding mechanism. Principal Findings We found that nanomolar concentrations of DBT, but not other organotins tested, inhibit ligand binding to GR and its transcriptional activity. Docking analysis indicated that DBT inhibits GR activation allosterically by inserting into a site close to the steroid-binding pocket, which disrupts a key interaction between the A-ring of the glucocorticoid and the GR. DBT inhibited glucocorticoid-induced expression of phosphoenolpyruvate carboxykinase (PEPCK) and tyrosine-aminotransferase (TAT) and abolished the glucocorticoid-mediated transrepression of TNF-α-induced NF-κB activity. Moreover, DBT abrogated the glucocorticoid-mediated suppression of interleukin-6 (IL-6) and TNF-α production in lipopolysaccharide (LPS)-stimulated native human macrophages and human THP-1 macrophages. Conclusions DBT inhibits ligand binding to GR and subsequent activation of the receptor. By blocking GR activation, DBT may disturb metabolic functions and modulation of the immune system, providing an explanation for some of the toxic effects of this organotin. PMID:18958157

  19. Dibutyltin disrupts glucocorticoid receptor function and impairs glucocorticoid-induced suppression of cytokine production.

    PubMed

    Gumy, Christel; Chandsawangbhuwana, Charlie; Dzyakanchuk, Anna A; Kratschmar, Denise V; Baker, Michael E; Odermatt, Alex

    2008-01-01

    Organotins are highly toxic and widely distributed environmental chemicals. Dibutyltin (DBT) is used as stabilizer in the production of polyvinyl chloride plastics, and it is also the major metabolite formed from tributyltin (TBT) in vivo. DBT is immunotoxic, however, the responsible targets remain to be defined. Due to the importance of glucocorticoids in immune-modulation, we investigated whether DBT could interfere with glucocorticoid receptor (GR) function. We used HEK-293 cells transiently transfected with human GR as well as rat H4IIE hepatoma cells and native human macrophages and human THP-1 macrophages expressing endogenous receptor to study organotin effects on GR function. Docking of organotins was used to investigate the binding mechanism. We found that nanomolar concentrations of DBT, but not other organotins tested, inhibit ligand binding to GR and its transcriptional activity. Docking analysis indicated that DBT inhibits GR activation allosterically by inserting into a site close to the steroid-binding pocket, which disrupts a key interaction between the A-ring of the glucocorticoid and the GR. DBT inhibited glucocorticoid-induced expression of phosphoenolpyruvate carboxykinase (PEPCK) and tyrosine-aminotransferase (TAT) and abolished the glucocorticoid-mediated transrepression of TNF-alpha-induced NF-kappaB activity. Moreover, DBT abrogated the glucocorticoid-mediated suppression of interleukin-6 (IL-6) and TNF-alpha production in lipopolysaccharide (LPS)-stimulated native human macrophages and human THP-1 macrophages. DBT inhibits ligand binding to GR and subsequent activation of the receptor. By blocking GR activation, DBT may disturb metabolic functions and modulation of the immune system, providing an explanation for some of the toxic effects of this organotin.

  20. Roles of mineralocorticoid and glucocorticoid receptors in the regulation of progenitor proliferation in the adult hippocampus.

    PubMed

    Wong, Edmund Y H; Herbert, Joe

    2005-08-01

    New neurons are produced continually in the dentate gyrus of the hippocampus. Numerous factors modulate the rate of neuron production. One of the most important is the adrenal-derived corticoids. Raised levels of corticoids suppress proliferation of progenitor cells, while removal of corticoids by adrenalectomy reverses this. The exact mechanisms by which corticoids mediate such regulation are unknown, but corticoids are believed to act through the receptors for mineralocorticoids (MR) and glucocorticoids (GR). Previous reports regarding the roles of these receptors in regulating cell proliferation came to contrasting conclusions. Here we use both agonists and antagonists to these receptors in adult male rats to investigate and clarify their roles. Blockade of MR with spironolactone in adrenalectomised male rats implanted with a corticosterone pellet to reproduce basal levels enhanced proliferation, whereas treatment with the GR antagonist mifepristone had no effect. However, mifepristone reversed the suppressive effect of additional corticosterone in intact rats. Both aldosterone and RU362, agonists of MR and GR, respectively, reduced proliferation in adrenalectomised rats, and combined treatment with both agonists had an additional suppressive action. These results clearly show that occupancies of both receptors act in the same direction on progenitor proliferation. The existence of two receptors with different affinities for corticoids may ensure that proliferation of progenitor cells in the adult dentate gyrus is regulated across the range of adrenal corticoid activity, including both basal and stressful contexts. Although a small proportion of newly formed cells may express GR and MR, corticosterone probably regulates proliferation indirectly through other local cells.

  1. Identifying a Mechanism for Crosstalk Between the Estrogen and Glucocorticoid Receptors | Center for Cancer Research

    Cancer.gov

    Estrogen has long been known to play important roles in the development and progression of breast cancer. Its receptor (ER), a member of the steroid receptor family, binds to estrogen response elements (EREs) in DNA and regulates gene transcription. More recently, another steroid receptor family member, the glucocorticoid receptor (GR), has been implicated in breast cancer

  2. Glucocorticoid Receptor Polymorphisms and Outcomes in Pediatric Septic Shock.

    PubMed

    Cvijanovich, Natalie Z; Anas, Nick; Allen, Geoffrey L; Thomas, Neal J; Bigham, Michael T; Weiss, Scott L; Fitzgerald, Julie; Checchia, Paul A; Meyer, Keith; Quasney, Michael; Gedeit, Rainer; Freishtat, Robert J; Nowak, Jeffrey; Raj, Shekhar S; Gertz, Shira; Grunwell, Jocelyn R; Opoka, Amy; Wong, Hector R

    2017-04-01

    Polymorphisms of the glucocorticoid receptor gene are associated with outcome and corticosteroid responsiveness among patients with inflammatory disorders. We conducted a candidate gene association study to test the hypothesis that these polymorphisms are associated with outcome and corticosteroid responsiveness among children with septic shock. We genotyped 482 children with septic shock for the presence of two glucocorticoid receptor polymorphisms (rs56149945 and rs41423247) associated with increased sensitivity and one glucocorticoid receptor polymorphism (rs6198) associated with decreased sensitivity to corticosteroids. The primary outcome variable was complicated course, defined as 28-day mortality or the persistence of two or more organ failures 7 days after a septic shock diagnosis. We used logistic regression to test for an association between corticosteroid exposure and outcome, within genotype group, and adjusted for illness severity. Multiple PICUs in the United States. Standard care. There were no differences in outcome when comparing the various genotype groups. Among patients homozygous for the wild-type glucocorticoid receptor allele, corticosteroids were independently associated with increased odds of complicated course (odds ratio, 2.30; 95% CI, 1.01-5.21; p = 0.047). Based on these glucocorticoid receptor polymorphisms, we could not detect a beneficial effect of corticosteroids among any genotype group. Among children homozygous for the wild-type allele, corticosteroids were independently associated with increased odds of poor outcome.

  3. Radiosequence analysis of the human progestin receptor charged with ( sup 3 H)promegestone. A comparison with the glucocorticoid receptor

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Stroemstedt, P.E.B.; Berkenstam, A.; Joernvall, H.G.

    1990-08-05

    Partially purified preparations of the human progestin receptor and the human and rat glucocorticoid receptor proteins were covalently charged with the synthetic progestin, ({sup 3}H)promegestone, by photoaffinity labeling. After labeling, the denaturated protein was cleaved and the mixture of peptides subjected to radiosequence analysis as previously described for the rat glucocorticoid receptor protein. The radioactivity labels identified, corresponded to Met-759 and Met-909 after photoaffinity labeling of the human progestin receptor, and Met-622 and Cys-754 after labeling of the rat glucocorticoid receptor. The residues labeled in the glucocorticoid receptor are the same as those previously reported to bind triamcinolone actonide. Themore » corresponding residues were also labeled in the human glucocorticoid receptor. Met-759 of the progestin receptor and Met-622 of the rat glucocorticoid receptor are positioned within a segment with an overall high degree of sequence similarity and are equivalent. However, Met-909 (progestin receptor) and Cys-754 (glucocorticoid receptor) do not occur within equivalent segments of the two proteins. Thus, although the two classes of steroid hormone share a common structure within the A-ring, there are subtle differences in their interaction with the two separate receptor proteins.« less

  4. The FKBP51 Glucocorticoid Receptor Co-Chaperone: Regulation, Function, and Implications in Health and Disease.

    PubMed

    Fries, Gabriel R; Gassen, Nils C; Rein, Theo

    2017-12-05

    Among the chaperones and co-chaperones regulating the glucocorticoid receptor (GR), FK506 binding protein (FKBP) 51 is the most intensely investigated across different disciplines. This review provides an update on the role of the different co-chaperones of Hsp70 and Hsp90 in the regulation of GR function. The development leading to the focus on FKBP51 is outlined. Further, a survey of the vast literature on the mechanism and function of FKBP51 is provided. This includes its structure and biochemical function, its regulation on different levels-transcription, post-transcription, and post-translation-and its function in signaling pathways. The evidence portraying FKBP51 as a scaffolding protein organizing protein complexes rather than a chaperone contributing to the folding of individual proteins is collated. Finally, FKBP51's involvement in physiology and disease is outlined, and the promising efforts in developing drugs targeting FKBP51 are discussed.

  5. How glucocorticoid receptors modulate the activity of other transcription factors: a scope beyond tethering.

    PubMed

    Ratman, Dariusz; Vanden Berghe, Wim; Dejager, Lien; Libert, Claude; Tavernier, Jan; Beck, Ilse M; De Bosscher, Karolien

    2013-11-05

    The activity of the glucocorticoid receptor (GR), a nuclear receptor transcription factor belonging to subclass 3C of the steroid/thyroid hormone receptor superfamily, is typically triggered by glucocorticoid hormones. Apart from driving gene transcription via binding onto glucocorticoid response elements in regulatory regions of particular target genes, GR can also inhibit gene expression via transrepression, a mechanism largely based on protein:protein interactions. Hereby GR can influence the activity of other transcription factors, without contacting DNA itself. GR is known to inhibit the activity of a growing list of immune-regulating transcription factors. Hence, GCs still rule the clinic for treatments of inflammatory disorders, notwithstanding concomitant deleterious side effects. Although patience is a virtue when it comes to deciphering the many mechanisms GR uses to influence various signaling pathways, the current review is testimony of the fact that groundbreaking mechanistic work has been accumulating over the past years and steadily continues to grow. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  6. Selective Androgen Receptor Down-Regulators (SARDs): A New Prostate Cancer Therapy

    DTIC Science & Technology

    2007-10-01

    PCa (9). Thus far, the techniques that have been used to down-regulate the AR include antisense oligonucleotides (10, 11), ribozyme treatments (12...Our findings suggest that ICI may present a useful treatment option for patients with AR-dependent PCa. Unlike the ribozyme , antisense, siRNA, or...Catalytic cleavage of the androgen receptor messenger RNA and functional inhibition of androgen receptor activity by a hammerhead ribozyme . Mol Endocrinol

  7. STAT5-glucocorticoid receptor interaction and MTF-1 regulate the expression of ZnT2 (Slc30a2) in pancreatic acinar cells

    PubMed Central

    Guo, Liang; Lichten, Louis A.; Ryu, Moon-Suhn; Liuzzi, Juan P.; Wang, Fudi; Cousins, Robert J.

    2010-01-01

    The exocrine pancreas plays an important role in endogenous zinc loss by regulating excretion into the intestinal tract and hence influences the dietary zinc requirement. The present experiments show that the zinc transporter ZnT2 (Slc30a2) is localized to the zymogen granules and that dietary zinc restriction in mice decreased the zinc concentration of zymogen granules and ZnT2 expression. Excess zinc given orally increased ZnT2 expression and was associated with increased pancreatic zinc accumulation. Rat AR42J acinar cells when induced into a secretory phenotype, using the glucocorticoid analog dexamethasone (DEX), exhibited increased ZnT2 expression and labile zinc as measured with a fluorophore. DEX administrated to mice also induced ZnT2 expression that accompanied a reduction of the pancreatic zinc content. ZnT2 promoter analyses identified elements required for responsiveness to zinc and DEX. Zinc regulation was traced to a MRE located downstream from the ZnT2 transcription start site. Responsiveness to DEX is produced by two upstream STAT5 binding sites that require the glucocorticoid receptor for activation. ZnT2 knockdown in the AR42J cells using siRNA resulted in increased cytoplasmic zinc and decreased zymogen granule zinc that further demonstrated that ZnT2 may mediate the sequestration of zinc into zymogen granules. We conclude, based upon experiments with intact mice and pancreatic acinar cells in culture, that ZnT2 participates in zinc transport into pancreatic zymogen granules through a glucocorticoid pathway requiring glucocorticoid receptor and STAT5, and zinc-regulated signaling pathways requiring MTF-1. The ZnT2 transporter appears to function in a physiologically responsive manner involving entero-pancreatic zinc trafficking. PMID:20133611

  8. Differential effects of the new glucocorticoid receptor antagonist ORG 34517 and RU486 (mifepristone) on glucocorticoid receptor nuclear translocation in the AtT20 cell line.

    PubMed

    Peeters, B W M M; Ruigt, G S F; Craighead, M; Kitchener, P

    2008-12-01

    Glucocorticoid agonists bind to cytoplasmic glucocorticoid receptors (GRs) and subsequently translocate as an agonist-GR complex into the nucleus. In the nucleus the complex regulates the transcription of target genes. A number of GR antagonists (RU486, progesterone, RU40555) have also been shown to induce receptor translocation. These compounds should be regarded as partial agonists. For the nonselective progesterone receptor antagonists, RTI3021-012 and RTI3021-022, it was shown that GR antagonism is possible without the induction of GR translocation. In the present studies, the new GR antagonist, ORG 34517, was investigated for its potential to induce GR translocation and to antagonize corticosterone-induced GR translocation in the AtT20 (mouse pituitary) cell line. ORG 34517 was compared to RU486. In contrast to RU486, ORG 34517 (at doses up to 3 x 10(-7) M) did not induce GR translocation, but was able to block corticosterone (3 x 10(-8) M) induced GR translocation. ORG 34517 can be regarded as a true competitive GR antagonist without partial agonistic activities.

  9. Luman/CREB3 recruitment factor regulates glucocorticoid receptor activity and is essential for prolactin-mediated maternal instinct.

    PubMed

    Martyn, Amanda C; Choleris, Elena; Gillis, Daniel J; Armstrong, John N; Amor, Talya R; McCluggage, Adam R R; Turner, Patricia V; Liang, Genqing; Cai, Kimberly; Lu, Ray

    2012-12-01

    The hypothalamic-pituitary-adrenal (HPA) axis is a major part of the neuroendocrine system in animal responses to stress. It is known that the HPA axis is attenuated at parturition to prevent detrimental effects of glucocorticoid secretion including inhibition of lactation and maternal responsiveness. Luman/CREB3 recruitment factor (LRF) was identified as a negative regulator of CREB3 which is involved in the endoplasmic reticulum stress response. Here, we report a LRF gene knockout mouse line that has a severe maternal behavioral defect. LRF(-/-) females lacked the instinct to tend pups; 80% of their litters died within 24 h, while most pups survived if cross-fostered. Prolactin levels were significantly repressed in lactating LRF(-/-) dams, with glucocorticoid receptor (GR) signaling markedly augmented. In cell culture, LRF repressed transcriptional activity of GR and promoted its protein degradation. LRF was found to colocalize with the known GR repressor, RIP140/NRIP1, which inhibits the activity by GR within specific nuclear punctates that are similar to LRF nuclear bodies. Furthermore, administration of prolactin or the GR antagonist RU486 restored maternal responses in mutant females. We thus postulate that LRF plays a critical role in the attenuation of the HPA axis through repression of glucocorticoid stress signaling during parturition and the postpartum period.

  10. Identifying a Mechanism for Crosstalk Between the Estrogen and Glucocorticoid Receptors | Center for Cancer Research

    Cancer.gov

    Estrogen has long been known to play important roles in the development and progression of breast cancer. Its receptor (ER), a member of the steroid receptor family, binds to estrogen response elements (EREs) in DNA and regulates gene transcription. More recently, another steroid receptor family member, the glucocorticoid receptor (GR), has been implicated in breast cancer progression, and ER/GR status is an important predictor of breast cancer outcome.

  11. Mapping the Dynamics of the Glucocorticoid Receptor within the Nuclear Landscape.

    PubMed

    Stortz, Martin; Presman, Diego M; Bruno, Luciana; Annibale, Paolo; Dansey, Maria V; Burton, Gerardo; Gratton, Enrico; Pecci, Adali; Levi, Valeria

    2017-07-24

    The distribution of the transcription machinery among different sub-nuclear domains raises the question on how the architecture of the nucleus modulates the transcriptional response. Here, we used fluorescence fluctuation analyses to quantitatively explore the organization of the glucocorticoid receptor (GR) in the interphase nucleus of living cells. We found that this ligand-activated transcription factor diffuses within the nucleus and dynamically interacts with bodies enriched in the coregulator NCoA-2, DNA-dependent foci and chromatin targets. The distribution of the receptor among the nuclear compartments depends on NCoA-2 and the conformation of the receptor as assessed with synthetic ligands and GR mutants with impaired transcriptional abilities. Our results suggest that the partition of the receptor in different nuclear reservoirs ultimately regulates the concentration of receptor available for the interaction with specific targets, and thus has an impact on transcription regulation.

  12. Brain-Derived Neurotrophic Factor Signaling Rewrites the Glucocorticoid Transcriptome via Glucocorticoid Receptor Phosphorylation

    PubMed Central

    Lambert, W. Marcus; Xu, Chong-Feng; Neubert, Thomas A.; Chao, Moses V.

    2013-01-01

    Abnormal glucocorticoid and neurotrophin signaling has been implicated in numerous psychiatric disorders. However, the impact of neurotrophic signaling on glucocorticoid receptor (GR)-dependent gene expression is not understood. We therefore examined the impact of brain-derived neurotrophic factor (BDNF) signaling on GR transcriptional regulatory function by gene expression profiling in primary rat cortical neurons stimulated with the selective GR agonist dexamethasone (Dex) and BDNF, alone or in combination. Simultaneous treatment with BDNF and Dex elicited a unique set of GR-responsive genes associated with neuronal growth and differentiation and also enhanced the induction of a large number of Dex-sensitive genes. BDNF via its receptor TrkB enhanced the transcriptional activity of a synthetic GR reporter, suggesting a direct effect of BDNF signaling on GR function. Indeed, BDNF treatment induces the phosphorylation of GR at serine 155 (S155) and serine 287 (S287). Expression of a nonphosphorylatable mutant (GR S155A/S287A) impaired the induction of a subset of BDNF- and Dex-regulated genes. Mechanistically, BDNF-induced GR phosphorylation increased GR occupancy and cofactor recruitment at the promoter of a BDNF-enhanced gene. GR phosphorylation in vivo is sensitive to changes in the levels of BDNF and TrkB as well as stress. Therefore, BDNF signaling specifies and amplifies the GR transcriptome through a coordinated GR phosphorylation-dependent detection mechanism. PMID:23878391

  13. CXC chemokine ligand 4 (CXCL4) down-regulates CC chemokine receptor expression on human monocytes.

    PubMed

    Schwartzkopff, Franziska; Petersen, Frank; Grimm, Tobias Alexander; Brandt, Ernst

    2012-02-01

    During acute inflammation, monocytes are essential in abolishing invading micro-organisms and encouraging wound healing. Recruitment by CC chemokines is an important step in targeting monocytes to the inflamed tissue. However, cell surface expression of the corresponding chemokine receptors is subject to regulation by various endogenous stimuli which so far have not been comprehensively identified. We report that the platelet-derived CXC chemokine ligand 4 (CXCL4), a known activator of human monocytes, induces down-regulation of CC chemokine receptors (CCR) 1, -2, and -5, resulting in drastic impairment of monocyte chemotactic migration towards cognate CC chemokine ligands (CCL) for these receptors. Interestingly, CXCL4-mediated down-regulation of CCR1, CCR2 and CCR5 was strongly dependent on the chemokine's ability to stimulate autocrine/paracrine release of TNF-α. In turn, TNF-α induced the secretion CCL3 and CCL4, two chemokines selective for CCR1 and CCR5, while the secretion of CCR2-ligand CCL2 was TNF-α-independent. Culture supernatants of CXCL4-stimulated monocytes as well as chemokine-enriched preparations thereof reproduced CXCL4-induced CCR down-regulation. In conclusion, CXCL4 may act as a selective regulator of monocyte migration by stimulating the release of autocrine, receptor-desensitizing chemokine ligands. Our results stress a co-ordinating role for CXCL4 in the cross-talk between platelets and monocytes during early inflammation.

  14. Serum and Glucocorticoid Regulated Kinase 1 in Sodium Homeostasis

    PubMed Central

    Lou, Yiyun; Zhang, Fan; Luo, Yuqin; Wang, Liya; Huang, Shisi; Jin, Fan

    2016-01-01

    The ubiquitously expressed serum and glucocorticoid regulated kinase 1 (SGK1) is tightly regulated by osmotic and hormonal signals, including glucocorticoids and mineralocorticoids. Recently, SGK1 has been implicated as a signal hub for the regulation of sodium transport. SGK1 modulates the activities of multiple ion channels and carriers, such as epithelial sodium channel (ENaC), voltage-gated sodium channel (Nav1.5), sodium hydrogen exchangers 1 and 3 (NHE1 and NHE3), sodium-chloride symporter (NCC), and sodium-potassium-chloride cotransporter 2 (NKCC2); as well as the sodium-potassium adenosine triphosphatase (Na+/K+-ATPase) and type A natriuretic peptide receptor (NPR-A). Accordingly, SGK1 is implicated in the physiology and pathophysiology of Na+ homeostasis. Here, we focus particularly on recent findings of SGK1’s involvement in Na+ transport in renal sodium reabsorption, hormone-stimulated salt appetite and fluid balance and discuss the abnormal SGK1-mediated Na+ reabsorption in hypertension, heart disease, edema with diabetes, and embryo implantation failure. PMID:27517916

  15. Regulation of the glucocorticoid receptor via a BET-dependent enhancer drives antiandrogen resistance in prostate cancer.

    PubMed

    Shah, Neel; Wang, Ping; Wongvipat, John; Karthaus, Wouter R; Abida, Wassim; Armenia, Joshua; Rockowitz, Shira; Drier, Yotam; Bernstein, Bradley E; Long, Henry W; Freedman, Matthew L; Arora, Vivek K; Zheng, Deyou; Sawyers, Charles L

    2017-09-11

    In prostate cancer, resistance to the antiandrogen enzalutamide (Enz) can occur through bypass of androgen receptor (AR) blockade by the glucocorticoid receptor (GR). In contrast to fixed genomic alterations, here we show that GR-mediated antiandrogen resistance is adaptive and reversible due to regulation of GR expression by a tissue-specific enhancer. GR expression is silenced in prostate cancer by a combination of AR binding and EZH2-mediated repression at the GR locus, but is restored in advanced prostate cancers upon reversion of both repressive signals. Remarkably, BET bromodomain inhibition resensitizes drug-resistant tumors to Enz by selectively impairing the GR signaling axis via this enhancer. In addition to revealing an underlying molecular mechanism of GR-driven drug resistance, these data suggest that inhibitors of broadly active chromatin-readers could have utility in nuanced clinical contexts of acquired drug resistance with a more favorable therapeutic index.

  16. Effects of suspension on tissue levels of glucocorticoid receptors

    NASA Technical Reports Server (NTRS)

    Steffen, J. M.

    1984-01-01

    Differential muscle responses can be simulated by hypokinetic/hypodynamic (H/H) suspension of rats with complete unloading of the hindlimb muscles. Since mechanism(s) underlying these atrophic effects were not clearly elucidated, experiments were initiated to investigate a possible role for glucocorticoids in the physiological and biochemical responses to H/H. The principal objective was to assess the potential for alterations in peripheral responsiveness to glucocorticoids in response to H/H. Studies have initially focused on the determination of tissue levels of glucocorticoid receptors as one index of hormonal sensitivity at the cellular level. Four hindlimb muscles (soleus, gastrocnemius, plantaris and EDL), previously demonstrated to exhibit differential responses to H/H, were investigated. Receptor levels in other glucocorticoid sensitive tissues (heart, liver, and kidney) were determined. Male rats (180-200g) were suspended for 7 or 14 days, sacrificed by cervical dislocation, and the tissues excised.

  17. DNA binding triggers tetramerization of the glucocorticoid receptor in live cells

    PubMed Central

    Presman, Diego M.; Ganguly, Sourav; Schiltz, R. Louis; Johnson, Thomas A.; Karpova, Tatiana S.; Hager, Gordon L.

    2016-01-01

    Transcription factors dynamically bind to chromatin and are essential for the regulation of genes. Although a large percentage of these proteins appear to self-associate to form dimers or higher order oligomers, the stoichiometry of DNA-bound transcription factors has been poorly characterized in vivo. The glucocorticoid receptor (GR) is a ligand-regulated transcription factor widely believed to act as a dimer or a monomer. Using a unique set of imaging techniques coupled with a cell line containing an array of DNA binding elements, we show that GR is predominantly a tetramer when bound to its target DNA. We find that DNA binding triggers an interdomain allosteric regulation within the GR, leading to tetramerization. We therefore propose that dynamic changes in GR stoichiometry represent a previously unidentified level of regulation in steroid receptor activation. Quaternary structure analysis of other members of the steroid receptor family (estrogen, androgen, and progesterone receptors) reveals variation in oligomerization states among this family of transcription factors. Because GR’s oligomerization state has been implicated in therapy outcome, our findings open new doors to the rational design of novel GR ligands and redefine the quaternary structure of steroid receptors. PMID:27382178

  18. Differential regulation of the transcriptional activity of the glucocorticoid receptor through site-specific phosphorylation.

    PubMed

    Kumar, Raj; Calhoun, William J

    2008-12-01

    Post-translational modifications such as phosphorylation are known to play an important role in the gene regulation by the transcription factors including the nuclear hormone receptor superfamily of which the glucocorticoid receptor (GR) is a member. Protein phosphorylation often switches cellular activity from one state to another. Like many other transcription factors, the GR is a phosphoprotein, and phosphorylation plays an important role in the regulation of GR activity. Cell signaling pathways that regulate phosphorylation of the GR and its associated proteins are important determinants of GR function under various physiological conditions. While the role of many phosphorylation sites in the GR is still not fully understood, the role of others is clearer. Several aspects of transcription factor function, including DNA binding affinity, interaction of transactivation domains with the transcription initiation complex, and shuttling between the cytoplasmic compartments, have all been linked to site-specific phosphorylation. All major phosphorylation sites in the human GR are located in the N-terminal domain including the major transactivation domain, AF1. Available literature clearly indicates that many of these potential phosphorylation sites are substrates for multiple kinases, suggesting the potential for a very complex regulatory network. Phosphorylated GR interacts favorably with critical coregulatory proteins and subsequently enhances transcriptional activity. In addition, the activities and specificities of coregulators may be subject to similar regulation by phosphorylation. Regulation of the GR activity due to phosphorylation appears to be site-specific and dependent upon specific cell signaling cascade. Taken together, site-specific phosphorylation and related kinase pathways play an important role in the action of the GR, and more precise mechanistic information will lead to fuller understanding of the complex nature of gene regulation by the GR- and

  19. Luman/CREB3 Recruitment Factor Regulates Glucocorticoid Receptor Activity and Is Essential for Prolactin-Mediated Maternal Instinct

    PubMed Central

    Martyn, Amanda C.; Choleris, Elena; Gillis, Daniel J.; Armstrong, John N.; Amor, Talya R.; McCluggage, Adam R. R.; Turner, Patricia V.; Liang, Genqing; Cai, Kimberly

    2012-01-01

    The hypothalamic-pituitary-adrenal (HPA) axis is a major part of the neuroendocrine system in animal responses to stress. It is known that the HPA axis is attenuated at parturition to prevent detrimental effects of glucocorticoid secretion including inhibition of lactation and maternal responsiveness. Luman/CREB3 recruitment factor (LRF) was identified as a negative regulator of CREB3 which is involved in the endoplasmic reticulum stress response. Here, we report a LRF gene knockout mouse line that has a severe maternal behavioral defect. LRF−/− females lacked the instinct to tend pups; 80% of their litters died within 24 h, while most pups survived if cross-fostered. Prolactin levels were significantly repressed in lactating LRF−/− dams, with glucocorticoid receptor (GR) signaling markedly augmented. In cell culture, LRF repressed transcriptional activity of GR and promoted its protein degradation. LRF was found to colocalize with the known GR repressor, RIP140/NRIP1, which inhibits the activity by GR within specific nuclear punctates that are similar to LRF nuclear bodies. Furthermore, administration of prolactin or the GR antagonist RU486 restored maternal responses in mutant females. We thus postulate that LRF plays a critical role in the attenuation of the HPA axis through repression of glucocorticoid stress signaling during parturition and the postpartum period. PMID:23071095

  20. Uterine glucocorticoid receptors are critical for fertility in mice through control of embryo implantation and decidualization

    PubMed Central

    Whirledge, Shannon D.; Oakley, Robert H.; Myers, Page H.; Lydon, John P.; DeMayo, Francesco; Cidlowski, John A.

    2015-01-01

    In addition to the well-characterized role of the sex steroid receptors in fertility and reproduction, organs of the female reproductive tract are also regulated by the hypothalamic–pituitary–adrenal axis. These endocrine organs are sensitive to stress-mediated actions of glucocorticoids, and the mouse uterus contains high levels of the glucocorticoid receptor (GR). Although the presence of GR in the uterus is well established, uterine glucocorticoid signaling has been largely ignored in terms of its reproductive and/or immunomodulatory functions on fertility. To define the direct in vivo function of glucocorticoid signaling in adult uterine physiology, we generated a uterine-specific GR knockout (uterine GR KO) mouse using the PRcre mouse model. The uterine GR KO mice display a profound subfertile phenotype, including a significant delay to first litter and decreased pups per litter. Early defects in pregnancy are evident as reduced blastocyst implantation and subsequent defects in stromal cell decidualization, including decreased proliferation, aberrant apoptosis, and altered gene expression. The deficiency in uterine GR signaling resulted in an exaggerated inflammatory response to induced decidualization, including altered immune cell recruitment. These results demonstrate that GR is required to establish the necessary cellular context for maintaining normal uterine biology and fertility through the regulation of uterine-specific actions. PMID:26598666

  1. MicroRNAs May Mediate the Down-Regulation of Neurokinin-1 Receptor in Chronic Bladder Pain Syndrome

    PubMed Central

    Sanchez Freire, Veronica; Burkhard, Fiona C.; Kessler, Thomas M.; Kuhn, Annette; Draeger, Annette; Monastyrskaya, Katia

    2010-01-01

    Bladder pain syndrome (BPS) is a clinical syndrome of pelvic pain and urinary urgency-frequency in the absence of a specific cause. Investigating the expression levels of genes involved in the regulation of epithelial permeability, bladder contractility, and inflammation, we show that neurokinin (NK)1 and NK2 tachykinin receptors were significantly down-regulated in BPS patients. Tight junction proteins zona occludens-1, junctional adherins molecule -1, and occludin were similarly down-regulated, implicating increased urothelial permeability, whereas bradykinin B1 receptor, cannabinoid receptor CB1 and muscarinic receptors M3-M5 were up-regulated. Using cell-based models, we show that prolonged exposure of NK1R to substance P caused a decrease of NK1R mRNA levels and a concomitant increase of regulatory micro(mi)RNAs miR-449b and miR-500. In the biopsies of BPS patients, the same miRNAs were significantly increased, suggesting that BPS promotes an attenuation of NK1R synthesis via activation of specific miRNAs. We confirm this hypothesis by identifying 31 differentially expressed miRNAs in BPS patients and demonstrate a direct correlation between miR-449b, miR-500, miR-328, and miR-320 and a down-regulation of NK1R mRNA and/or protein levels. Our findings further the knowledge of the molecular mechanisms of BPS, and have relevance for other clinical conditions involving the NK1 receptor. PMID:20008142

  2. Membrane glucocorticoid receptors are localised in the extracellular matrix and signal through the MAPK pathway in mammalian skeletal muscle fibres

    PubMed Central

    Boncompagni, Simona; Arthurton, Lewis; Akujuru, Eugene; Pearson, Timothy; Steverding, Dietmar; Protasi, Feliciano; Mutungi, Gabriel

    2015-01-01

    A number of studies have previously proposed the existence of glucocorticoid receptors on the plasma membrane of many cell types, including skeletal muscle fibres. However, their exact localisation and the cellular signalling pathway(s) they utilise to communicate with the rest of the cell are still poorly understood. In this study, we investigated the localisation and the mechanism(s) underlying the non-genomic physiological functions of these receptors in mouse skeletal muscle cells. The results show that the receptors were localised in the cytoplasm in myoblasts, in the nucleus in myotubes, in the extracellular matrix, in satellite cells and in the proximity of mitochondria in adult muscle fibres. Also, they bound laminin in a glucocorticoid-dependent manner. Treating small skeletal muscle fibre bundles with the synthetic glucocorticoid beclomethasone dipropionate increased the phosphorylation (= activation) of extracellular signal-regulated kinases 1 and 2, c-Jun N-terminal kinase and p38 mitogen-activated protein kinase. This occurred within 5 min and depended on the fibre type and the duration of the treatment. It was also abolished by the glucocorticoid receptor inhibitor, mifepristone, and a monoclonal antibody against the receptor. From these results we conclude that the non-genomic/non-canonical physiological functions of glucocorticoids, in adult skeletal muscle fibres, are mediated by a glucocorticoid receptor localised in the extracellular matrix, in satellite cells and close to mitochondria, and involve activation of the mitogen-activated protein kinase pathway. PMID:25846902

  3. Down-regulation of Cyclooxygenase-2 by the Carboxyl Tail of the Angiotensin II Type 1 Receptor*

    PubMed Central

    Sood, Rapita; Minzel, Waleed; Rimon, Gilad; Tal, Sharon; Barki-Harrington, Liza

    2014-01-01

    The enzyme cyclooxygenase-2 (COX-2) plays an important role in the kidney by up-regulating the production of the vasoconstrictor hormone angiotensin II (AngII), which in turn down-regulates COX-2 expression via activation of the angiotensin II type 1 receptor (AT1) receptor. Chemical inhibition of the catalytic activity of COX-2 is a well-established strategy for treating inflammation but little is known of cellular mechanisms that dispose of the protein itself. Here we show that in addition to its indirect negative feedback on COX-2, AT1 also down-regulates the expression of the COX-2 protein via a pathway that does not involve G-protein or β-arrestin-dependent signaling. Instead, AT1 enhances the ubiquitination and subsequent degradation of the enzyme in the proteasome through elements in its cytosolic carboxyl tail (CT). We find that a mutant receptor that lacks the last 35 amino acids of its CT (Δ324) is devoid of its ability to reduce COX-2, and that expression of the CT sequence alone is sufficient to down-regulate COX-2. Collectively these results propose a new role for AT1 in regulating COX-2 expression in a mechanism that deviates from its canonical signaling pathways. Down-regulation of COX-2 by a short peptide that originates from AT1 may present as a basis for novel therapeutic means of eliminating excess COX-2 protein. PMID:25231994

  4. Influences of maternal and paternal PTSD on epigenetic regulation of the glucocorticoid receptor gene in Holocaust survivor offspring

    PubMed Central

    Desarnaud, Frank; Bader, Heather N.; Makotkine, Iouri; Flory, Janine D.; Bierer, Linda M.; Meaney, Michael J.

    2014-01-01

    Objective Differential effects of maternal and paternal PTSD have been observed in adult offspring of Holocaust survivors in both glucocorticoid receptor sensitivity and vulnerability to psychiatric disorder. The current study examined the relative influences of maternal and paternal PTSD on DNA methylation of the exon 1F promoter of the glucocorticoid receptor gene (NR3C1) in peripheral blood mononuclear cells (PBMCs), and its relationship to glucocorticoid receptor sensitivity, in Holocaust offspring. Method Adult offspring with at least one Holocaust survivor parent (n=80), and demographically similar participants without parental Holocaust exposure or PTSD (n=15) completed clinical interviews, self-report measures, and biological procedures. Blood samples were collected for analysis of glucocorticoid receptor gene exon 1F (GR-1F) promoter methylation and cortisol levels in response to low-dose dexamethasone, and two-way analysis of covariance was performed using maternal and paternal PTSD as main effects. Hierarchical-clustering analysis was used to permit visualization of maternal vs. paternal PTSD effects on clinical variables. Results A significant interaction demonstrated that in the absence of maternal PTSD, offspring with paternal PTSD showed higher GR-1F promoter methylation, whereas offspring with both maternal and paternal PTSD showed lower methylation. Lower GR-1F promoter methylation was significantly associated with greater post-dexamethasone cortisol suppression. The clustering analysis confirmed that maternal and paternal PTSD effects were differentially associated with clinical indicators. Conclusions This is the first study to demonstrate alterations of GR-1F promoter methylation in relation to parental PTSD and neuroendocrine outcomes. The moderation of paternal PTSD effects by maternal PTSD suggests different mechanisms for the intergenerational transmission of trauma-related vulnerabilities. PMID:24832930

  5. Increased antidepressant sensitivity after prefrontal cortex glucocorticoid receptor gene deletion in mice.

    PubMed

    Hussain, Rifat J; Jacobson, Lauren

    2015-01-01

    Our laboratory has previously shown that antidepressants regulate glucocorticoid receptor (GR) expression in the prefrontal cortex (PFC). To determine if PFC GR are involved in antidepressant effects on behavior or hypothalamic-pituitary-adrenocortical (HPA) axis activity, we treated floxed GR male mice with saline or 15 or 30 mg/kg/d imipramine after PFC injection of adeno-associated virus 2/9 vectors transducing expression of Cre recombinase, to knock-down GR (PFC-GRKD), or green fluorescent protein (PFC-GFP), to serve as a control. The pattern of virally transduced GR deletion, common to all imipramine treatment groups, included the infralimbic, prelimbic, and medial anterior cingulate cortex at its largest extent, but was confined to the prelimbic and anterior cingulate cortex at its smallest extent. PFC GR knock-down increased behavioral sensitivity to imipramine, with imipramine-treated PFC-GRKD but not PFC-GFP mice exhibiting significant decreases in depression-like immobility during forced swim. PFC GR deletion did not alter general locomotor activity. The 30 mg/kg dose of imipramine increased plasma corticosterone levels immediately after a 5-min forced swim, but PFC GR knock-down had no significant effect on plasma corticosterone under these experimental conditions. We conclude that PFC GR knock-down, likely limited to the medial prelimbic and anterior cingulate cortices, can increase behavioral sensitivity to antidepressants. These findings indicate a novel role for PFC GR in influencing antidepressant response. Copyright © 2014 Elsevier Inc. All rights reserved.

  6. Optimal experimental design in an epidermal growth factor receptor signalling and down-regulation model.

    PubMed

    Casey, F P; Baird, D; Feng, Q; Gutenkunst, R N; Waterfall, J J; Myers, C R; Brown, K S; Cerione, R A; Sethna, J P

    2007-05-01

    We apply the methods of optimal experimental design to a differential equation model for epidermal growth factor receptor signalling, trafficking and down-regulation. The model incorporates the role of a recently discovered protein complex made up of the E3 ubiquitin ligase, Cbl, the guanine exchange factor (GEF), Cool-1 (beta -Pix) and the Rho family G protein Cdc42. The complex has been suggested to be important in disrupting receptor down-regulation. We demonstrate that the model interactions can accurately reproduce the experimental observations, that they can be used to make predictions with accompanying uncertainties, and that we can apply ideas of optimal experimental design to suggest new experiments that reduce the uncertainty on unmeasurable components of the system.

  7. Disuse atrophy, plasma corticosterone, and muscle glucocorticoid receptor levels

    NASA Technical Reports Server (NTRS)

    Steffen, J. M.; Musacchia, X. J.

    1987-01-01

    The effect of whole-body suspension on the time course and the extent of plasma corticosterone changes and the tissue sensitivity to glucocorticoids were investigated in rats subjected to seven days of whole-body suspension. Plasma corticosterone increased significantly on the first and the third days of suspension, but returned to control levels by day seven. Muscle glucocorticoid receptors exhibited a characteristic hormonal specificity (evaluated in competitive-displacement experiments). In controls, receptor site concentration in the slow-twitch soleus was comparable to that in the fast-twitch gastrocnemius and plantaris, but was significantly less than in the extensor; seven days of suspension resulted in significant differential effects on muscle receptor levels. The largest increase in receptor concentration was observed in the soleus in which it remained elevated after the receptor levels in other muscles returned to normal.

  8. Glucocorticoid receptors in anorexia nervosa and Cushing's disease.

    PubMed

    Invitti, C; Redaelli, G; Baldi, G; Cavagnini, F

    1999-06-01

    Patients with anorexia nervosa do not display cushingoid features in spite of elevated cortisol plasma levels. Whether a cortisol resistance or a reduced availability of the metabolic substrates necessary to develop the effect of glucocorticoids is responsible for this has not been established. Twenty-two patients with severe restrictive anorexia nervosa, 10 patients with active Cushing's disease, and 24 healthy volunteers without psychiatric disorders or mood alterations were investigated. Glucocorticoid receptor characteristics were examined on mononuclear leukocytes by measuring [3H]dexamethasone binding and the effect of dexamethasone on [3H]thymidine incorporation, which represents an index of DNA synthesis. The number of glucocorticoid receptors on mononuclear leukocytes (MNL) was comparable in patients with anorexia nervosa, patients with active Cushing's disease, and normal subjects (binding capacity 3.3 +/- 0.23 vs. 3.7 +/- 0.30 and 3.5 +/- 0.20 fmol/10(6) cells). Conversely, glucocorticoid receptor affinity was significantly decreased in anorexia nervosa as well as in Cushing's patients compared to control subjects (dissociation constant 4.0 +/- 0.31 and 4.1 +/- 0.34 vs. 2.9 +/- 0.29 nmol/L, p < .001) and inversely correlated with the levels of urinary free cortisol in both groups of patients. Basal [3H]thymidine incorporation in MNL was significantly reduced in anorexia nervosa as well as in Cushing's patients compared to control subjects (p < .001) and was diminished by dexamethasone to an extent similar to control subjects in patients with anorexia nervosa, but significantly (p < .001) less in those with Cushing's disease. In patients with anorexia nervosa, the incorporation of [3H]thymidine into the MNL was inversely correlated with urinary free cortisol levels. These data indicate that the lack of cushingoid features in patients with anorexia nervosa is not ascribable to a reduced sensitivity to glucocorticoids but is more likely due to the paucity

  9. Both mineralocorticoid and glucocorticoid receptors regulate emotional memory in mice.

    PubMed

    Zhou, Ming; Bakker, Eveline H M; Velzing, Els H; Berger, Stefan; Oitzl, Melly; Joëls, Marian; Krugers, Harm J

    2010-11-01

    Corticosteroid hormones are thought to promote optimal behavioral adaptation under fearful conditions, primarily via glucocorticoid receptors (GRs). Here, we examined - using pharmacological and genetic approaches in mice - if mineralocorticoid receptors (MRs) also play a role in fearful memory formation. As expected, administration of the GR-antagonist RU38486 prior to training in a fear conditioning paradigm impaired contextual memory when tested 24 (but not when tested 3) h after training. Tone-cue memory was enhanced by RU38486 when tested at 4 (but not 25) h after training. Interestingly, pre (but not post)-training administration of MR antagonist spironolactone impaired contextual memory, both at 3 and 24h after training. Similar effects were also found in forebrain-specific MR knockout mice. Spironolactone also impaired tone-cue memory, but only at 4h after training. These results reveal that - in addition to GRs - MRs also play a critical role in establishing fear memories, particularly in the early phase of memory formation. Copyright © 2010 Elsevier Inc. All rights reserved.

  10. Prostaglandin E2 mediates growth arrest in NFS-60 cells by down-regulating interleukin-6 receptor expression.

    PubMed

    de Silva, Kumudika I; Daud, Asif N; Deng, JiangPing; Jones, Stephen B; Gamelli, Richard L; Shankar, Ravi

    2003-02-15

    Interleukin-6 (IL-6), a potent myeloid mitogen, and the immunosuppressive prostanoid prostaglandin E2 (PGE2) are elevated following thermal injury and sepsis. We have previously demonstrated that bone marrow myeloid commitment shifts toward monocytopoiesis and away from granulocytopoiesis during thermal injury and sepsis and that PGE2 plays a central role in this alteration. Here we investigated whether PGE2 can modulate IL-6-stimulated growth in the promyelocytic cell line, NFS-60, by down-regulating IL-6 receptor (IL-6r) expression. Exposure of NFS-60 cells to PGE2 suppressed IL-6-stimulated proliferation as well as IL-6r expression. Receptor down-regulation is functionally significant since IL-6-induced signal transduction through activators of transcription (STAT)-3 is also decreased. Down-regulation of IL-6r correlated with the ability of PGE2 to arrest cells in the G0/G1 phase of the cell cycle. PGE2 appears to signal through EP2 receptors. Butaprost (EP2 agonist) but not sulprostone (EP3 agonist) inhibited IL-6-stimulated proliferation. In addition, an EP2 antagonist (AH6809) alleviated the anti-proliferative effects of PGE2. NFS-60 cells express predominantly EP2 and EP4 receptors. While PGE2 down-regulated both the IL-6r protein and mRNA expression, it had no influence on EP2 or EP4 mRNA expression. The present study demonstrates that PGE2 is a potent down-regulator of IL-6r expression and thus may provide a mechanistic explanation for the granulocytopenia seen in thermal injury and sepsis.

  11. Regulation of corticoid and serotonin receptor brain system following early life exposure of glucocorticoids: long term implications for the neurobiology of mood.

    PubMed

    Vázquez, Delia M; Neal, Charles R; Patel, Paresh D; Kaciroti, Niko; López, Juan F

    2012-03-01

    Potent glucocorticoids (GC) administered early in life have improved premature infant survival dramatically. However, these agents may increase the risk for physical, neurological and behavior alterations. Anxiety, depression and attention difficulties are commonly described in adolescent and young adult survivors of prematurity. In the present study we administered vehicle, dexamethasone, or hydrocortisone to Sprague-Dawley rat pups on postnatal days 5 and 6, mimicking a short term clinical protocol commonly used in human infants. Two systems that are implicated in the regulation of stress and behavior were assessed: the limbic-hypothalamic-pituitary-adrenal axis [LHPA; glucocorticoid and mineralocorticoid receptors within] and the Serotonin (5-HT) system. We found that as adults, male Sprague-Dawley pups treated with GC showed agent specific altered growth, anxiety-related behavior, changes in corticoid response to novelty and gene expression changes within LHPA and 5-HT-related circuitry. The data suggest that prolonged GC-receptor stimulation during the early neonatal period can contribute to the development of individual differences in stress response and anxiety-related behavior later in life. Copyright © 2011 Elsevier Ltd. All rights reserved.

  12. Regulation of Corticoid and Serotonin Receptor Brain System following Early Life Exposure of Glucocorticoids: Long Term Implications for the Neurobiology of Mood

    PubMed Central

    Vázquez, Delia M.; Neal, Charles R.; Patel, Paresh D.; Kaciroti, Niko; López, Juan F.

    2011-01-01

    Potent glucocorticoids (GC) administered early in life has improved premature infant survival dramatically. However, these agents may increase the risk for physical, neurological and behavior alterations. Anxiety, depression and attention difficulties are commonly described in adolescent and young adult survivors of prematurity. In the present study we administered vehicle, dexamethasone, or hydrocortisone to Sprague-Dawley rat pups on postnatal days 5 and 6, mimicking a short term clinical protocol commonly used in human infants. Two systems that are implicated in the regulation of stress and behavior were assessed: the limbic-hypothalamic-pituitary-adrenal axis [LHPA, glucocorticoid and mineralocorticoid receptors within] and the Serotonin (5-HT) system. We found that as adults, male Sprague-Dawley pups treated with GC showed agent specific altered growth, anxiety-related behavior, changes in corticoid response to novelty and gene expression changes within LHPA and 5-HT–related circuitry. The data suggest that prolonged GC-receptor stimulation during the early neonatal period can contribute to the development of individual differences in stress response and anxiety-related behavior later in life. PMID:21855221

  13. Glucocorticoids are critical regulators of dendritic spine development and plasticity in vivo

    PubMed Central

    Liston, Conor; Gan, Wen-Biao

    2011-01-01

    Glucocorticoids are a family of hormones that coordinate diverse physiological processes in responding to stress. Prolonged glucocorticoid exposure over weeks has been linked to dendritic atrophy and spine loss in fixed tissue studies of adult brains, but it is unclear how glucocorticoids may affect the dynamic processes of dendritic spine formation and elimination in vivo. Furthermore, relatively few studies have examined the effects of stress and glucocorticoids on spines during the postnatal and adolescent period, which is characterized by rapid synaptogenesis followed by protracted synaptic pruning. To determine whether and to what extent glucocorticoids regulate dendritic spine development and plasticity, we used transcranial two-photon microscopy to track the formation and elimination of dendritic spines in vivo after treatment with glucocorticoids in developing and adult mice. Corticosterone, the principal murine glucocorticoid, had potent dose-dependent effects on dendritic spine dynamics, increasing spine turnover within several hours in the developing barrel cortex. The adult barrel cortex exhibited diminished baseline spine turnover rates, but these rates were also enhanced by corticosterone. Similar changes occurred in multiple cortical areas, suggesting a generalized effect. However, reducing endogenous glucocorticoid activity by dexamethasone suppression or corticosteroid receptor antagonists caused a substantial reduction in spine turnover rates, and the former was reversed by corticosterone replacement. Notably, we found that chronic glucocorticoid excess led to an abnormal loss of stable spines that were established early in life. Together, these findings establish a critical role for glucocorticoids in the development and maintenance of dendritic spines in the living cortex. PMID:21911374

  14. Methylation of the Glucocorticoid Receptor Gene Promoter in Preschoolers: Links with Internalizing Behavior Problems

    ERIC Educational Resources Information Center

    Parade, Stephanie H.; Ridout, Kathryn K.; Seifer, Ronald; Armstrong, David A.; Marsit, Carmen J.; McWilliams, Melissa A.; Tyrka, Audrey R.

    2016-01-01

    Accumulating evidence suggests that early adversity is linked to methylation of the glucocorticoid receptor (GR) gene, "NR3C1," which is a key regulator of the hypothalamic-pituitary-adrenal axis. Yet no prior work has considered the contribution of methylation of "NR3C1" to emerging behavior problems and psychopathology in…

  15. Up-regulation of Rho-associated kinase 1/2 by glucocorticoids promotes migration, invasion and metastasis of melanoma.

    PubMed

    Huang, Gao-Xiang; Wang, Yan; Su, Jie; Zhou, Peng; Li, Bo; Yin, Li-Juan; Lu, Jian

    2017-12-01

    Although glucocorticoids (GCs) regulate proliferation, differentiation and apoptosis of tumor cells, their influence on metastasis of tumor cells is poorly understood. Melanoma is a type of skin cancers with high metastasis. We investigated the effect of GCs on metastasis of melanoma cells and its mechanism. We found that GCs significantly promoted the adhesion, migration, invasion of melanoma cells in vitro and lung metastasis in experimental melanoma metastasis mice. Dexamethasone (Dex), a synthetic GC, did not change the RhoA, RhoB and RhoC signalings, but significantly increased the expression and activity of Rho-associated kinase 1/2 (ROCK1/2). The effect of Dex was to increase ROCK1/2 stability mediated by glucocorticoid receptor. Inhibiting ROCK1/2 activity with Y-27632, a ROCK1/2 inhibitor abrogated the pro-migration and pro-metastasis effects of GCs in vitro and in vivo, indicating that ROCK1/2 mediated the pro-metastasis effects of GCs. Activation of PI3K/AKT also contributed to the pro-migration and pro-invasion effects of Dex partially through up-regulating ROCK1/2 expression. Additionally, Dex also down-regulated the expression of tissue inhibitors of matrix metalloproteinase-2. Taken together, our findings provide new data to understand the possible promoting roles and mechanisms of GCs in melanoma metastasis. Copyright © 2017. Published by Elsevier B.V.

  16. Spliceosome Protein (SRp) Regulation of Glucocorticoid Receptor Isoforms and Glucocorticoid Response in Human Trabecular Meshwork Cells

    PubMed Central

    Jain, Ankur; Wordinger, Robert J.; Yorio, Thomas; Clark, Abbot F.

    2012-01-01

    Purpose. Glaucoma is a leading cause of visual impairment and blindness, with elevated intraocular pressure (IOP) as a major causative risk factor. Glucocorticoid (GC) therapy causes morphologic and biochemical changes in the trabecular meshwork (TM), an ocular tissue involved in regulating IOP, which can lead to the development of glaucoma in susceptible individuals (steroid responders). Steroid responders comprise 40% of the general population and are at higher risk of developing glaucoma. In addition, a majority of glaucoma patients are steroid responders. Differential distribution of various isoforms of GC receptor (GR) may be responsible for this heterogeneity in the steroid response. The alternatively spliced GRβ isoform acts as dominant negative regulator of classical GRα transcriptional activity. mRNA splicing is mediated by spliceosomes, which include serine-arginine rich proteins (SRps). The purpose of this study was to determine whether specific SRps regulate levels of these isoforms and thereby GC response in TM cells. Methods. Quantitative RT-PCR, Western blot analysis, and immunocytochemistry were used to determine the differential expression of different SRps (SRp20, 30c, and 40) in human normal and glaucomatous TM cell strains. Bioinformatics was used to find putative binding sites for SRp20 and SRp40 on exon 9 of the GR gene. A peptide modulator of splicing (bombesin) and SRp expression vectors were used to modulate SRp levels and determine their effects on GRα/GRβ ratios as well as dexamethasone (DEX) responsiveness via GRE- luciferase reporter activity, fibronectin, and myocilin induction in TM cells. Results. SRp20, SRp30c, and SRp40 regulate GR splicing and the GC response in TM cells. Modulation of SRp levels altered the GRβ/α ratio that correlated with DEX responsiveness. Bombesin decreased SRp20; increased SRp30c, SRp40 levels, and GRβ/α ratio, and suppressed DEX response in TM cells. Conclusions. Relative levels of SRp20, SRp30c

  17. The Selective Glucocorticoid Receptor Modulator Cort 113176 Reduces Neurodegeneration and Neuroinflammation in Wobbler Mice Spinal Cord.

    PubMed

    Meyer, Maria; Lara, Agustina; Hunt, Hazel; Belanoff, Joseph; de Kloet, E Ronald; Gonzalez Deniselle, Maria Claudia; De Nicola, Alejandro F

    2018-06-08

    Wobbler mice are experimental models for amyotrophic lateral sclerosis. As such they show motoneuron degeneration, motor deficits, and astrogliosis and microgliosis of the spinal cord. Additionally, Wobbler mice show increased plasma, spinal cord and brain corticosterone levels and focal adrenocortical hyperplasia, suggesting a pathogenic role for glucocorticoids in this disorder. Considering this endocrine background, we examined whether the glucocorticoid receptor (GR) modulator CORT 113176 prevents spinal cord neuropathology of Wobblers. CORT 113176 shows high affinity for the GR, with low or null affinity for other steroid receptors. We employed five-month-old genotyped Wobbler mice that received s.c. vehicle or 30 mg/kg/day for 4 days of CORT 113176 dissolved in sesame oil. The mice were used on the 4th day, 2 h after the last dose of CORT 113176. Vehicle-treated Wobbler mice presented vacuolated motoneurons, increased glial fibrillary acidic protein (GFAP)+ astrocytes and decreased glutamine synthase (GS)+ cells. There was strong neuroinflammation, shown by increased staining for IBA1+ microglia and CD11b mRNA, enhanced expression of tumor necrosis factor-α, its cognate receptor TNFR1, toll-like receptor 4, the inducible nitric oxide synthase, NFkB and the high-mobility group box 1 protein (HMGB1). Treatment of Wobbler mice with CORT 113176 reversed the abnormalities of motoneurons and down-regulated proinflammatory mediators and glial reactivity. Expression of glutamate transporters GLT1 and GLAST mRNAs and GLT1 protein was significantly enhanced over untreated Wobblers. In summary, antagonism of GR with CORT 113176 prevented neuropathology and showed anti-inflammatory and anti-glutamatergic effects in the spinal cord of Wobbler mice. Copyright © 2018 IBRO. Published by Elsevier Ltd. All rights reserved.

  18. Ras-dva Is a Novel Pit-1- and Glucocorticoid-Regulated Gene in the Embryonic Anterior Pituitary Gland

    PubMed Central

    Ellestad, Laura E.

    2013-01-01

    Glucocorticoids play a role in functional differentiation of pituitary somatotrophs and lactotrophs during embryogenesis. Ras-dva was identified as a gene regulated by anterior neural fold protein-1/homeobox expressed in embryonic stem cells-1, a transcription factor known to be critical in pituitary development, and has an expression profile in the chicken embryonic pituitary gland that is consistent with in vivo regulation by glucocorticoids. The objective of this study was to characterize expression and regulation of ras-dva mRNA in the developing chicken anterior pituitary. Pituitary ras-dva mRNA levels increased during embryogenesis to a maximum on embryonic day (e) 18 and then decreased and remained low or undetectable after hatch. Ras-dva expression was highly enriched in the pituitary gland on e18 relative to other tissues examined. Glucocorticoid treatment of pituitary cells from mid- and late-stage embryos rapidly increased ras-dva mRNA, suggesting it may be a direct transcriptional target of glucocorticoids. A reporter construct driven by 4 kb of the chicken ras-dva 5′-flanking region, containing six putative pituitary-specific transcription factor-1 (Pit-1) binding sites and two potential glucocorticoid receptor (GR) binding sites, was highly activated in embryonic pituitary cells and up-regulated by corticosterone. Mutagenesis of the most proximal Pit-1 site decreased promoter activity in chicken e11 pituitary cells, indicating regulation of ras-dva by Pit-1. However, mutating putative GR binding sites did not substantially reduce induction of ras-dva promoter activity by corticosterone, suggesting additional DNA elements within the 5′-flanking region are responsible for glucocorticoid regulation. We have identified ras-dva as a glucocorticoid-regulated gene that is likely expressed in cells of the Pit-1 lineage within the developing anterior pituitary gland. PMID:23161868

  19. Ras-dva is a novel Pit-1- and glucocorticoid-regulated gene in the embryonic anterior pituitary gland.

    PubMed

    Ellestad, Laura E; Porter, Tom E

    2013-01-01

    Glucocorticoids play a role in functional differentiation of pituitary somatotrophs and lactotrophs during embryogenesis. Ras-dva was identified as a gene regulated by anterior neural fold protein-1/homeobox expressed in embryonic stem cells-1, a transcription factor known to be critical in pituitary development, and has an expression profile in the chicken embryonic pituitary gland that is consistent with in vivo regulation by glucocorticoids. The objective of this study was to characterize expression and regulation of ras-dva mRNA in the developing chicken anterior pituitary. Pituitary ras-dva mRNA levels increased during embryogenesis to a maximum on embryonic day (e) 18 and then decreased and remained low or undetectable after hatch. Ras-dva expression was highly enriched in the pituitary gland on e18 relative to other tissues examined. Glucocorticoid treatment of pituitary cells from mid- and late-stage embryos rapidly increased ras-dva mRNA, suggesting it may be a direct transcriptional target of glucocorticoids. A reporter construct driven by 4 kb of the chicken ras-dva 5'-flanking region, containing six putative pituitary-specific transcription factor-1 (Pit-1) binding sites and two potential glucocorticoid receptor (GR) binding sites, was highly activated in embryonic pituitary cells and up-regulated by corticosterone. Mutagenesis of the most proximal Pit-1 site decreased promoter activity in chicken e11 pituitary cells, indicating regulation of ras-dva by Pit-1. However, mutating putative GR binding sites did not substantially reduce induction of ras-dva promoter activity by corticosterone, suggesting additional DNA elements within the 5'-flanking region are responsible for glucocorticoid regulation. We have identified ras-dva as a glucocorticoid-regulated gene that is likely expressed in cells of the Pit-1 lineage within the developing anterior pituitary gland.

  20. Coregulator profiling of the glucocorticoid receptor in lymphoid malignancies

    PubMed Central

    Clarisse, Dorien; Thommis, Jonathan; Van Wesemael, Karlien; Houtman, René; Ratman, Dariusz; Tavernier, Jan; Offner, Fritz; Beck, Ilse; De Bosscher, Karolien

    2017-01-01

    Coregulators cooperate with nuclear receptors, such as the glucocorticoid receptor (GR), to enhance or repress transcription. These regulatory proteins are implicated in cancer, yet, their role in lymphoid malignancies, including multiple myeloma (MM) and acute lymphoblastic leukemia (ALL), is largely unknown. Here, we report the use and extension of the microarray assay for real-time nuclear receptor coregulator interactions (MARCoNI) technology to detect coregulator associations with endogenous GR in cell lysates. We use MARCoNI to determine the GR coregulator profile of glucocorticoid-sensitive (MM and ALL) and glucocorticoid-resistant (ALL) cells, and identify common and unique coregulators for different cell line comparisons. Overall, we identify SRC-1/2/3, PGC-1α, RIP140 and DAX-1 as the strongest interacting coregulators of GR in MM and ALL cells and show that the interaction strength does not correlate with GR protein levels. Lastly, as a step towards patient samples, we determine the GR coregulator profile of peripheral blood mononuclear cells. We profile the interactions between GR and coregulators in MM and ALL cells and suggest to further explore the GR coregulator profile in hematological patient samples. PMID:29312638

  1. Coregulator profiling of the glucocorticoid receptor in lymphoid malignancies.

    PubMed

    Clarisse, Dorien; Thommis, Jonathan; Van Wesemael, Karlien; Houtman, René; Ratman, Dariusz; Tavernier, Jan; Offner, Fritz; Beck, Ilse; De Bosscher, Karolien

    2017-12-12

    Coregulators cooperate with nuclear receptors, such as the glucocorticoid receptor (GR), to enhance or repress transcription. These regulatory proteins are implicated in cancer, yet, their role in lymphoid malignancies, including multiple myeloma (MM) and acute lymphoblastic leukemia (ALL), is largely unknown. Here, we report the use and extension of the microarray assay for real-time nuclear receptor coregulator interactions (MARCoNI) technology to detect coregulator associations with endogenous GR in cell lysates. We use MARCoNI to determine the GR coregulator profile of glucocorticoid-sensitive (MM and ALL) and glucocorticoid-resistant (ALL) cells, and identify common and unique coregulators for different cell line comparisons. Overall, we identify SRC-1/2/3, PGC-1α, RIP140 and DAX-1 as the strongest interacting coregulators of GR in MM and ALL cells and show that the interaction strength does not correlate with GR protein levels. Lastly, as a step towards patient samples, we determine the GR coregulator profile of peripheral blood mononuclear cells. We profile the interactions between GR and coregulators in MM and ALL cells and suggest to further explore the GR coregulator profile in hematological patient samples.

  2. Epigenetic regulation of the glucocorticoid receptor promoter 1(7) in adult rats.

    PubMed

    Witzmann, Simone R; Turner, Jonathan D; Mériaux, Sophie B; Meijer, Onno C; Muller, Claude P

    2012-11-01

    Regulation of glucocorticoid receptor (GR) levels is an important stress adaptation mechanism. Transcription factor Nfgi-a and environmentally induced Gr promoter 1 7 methylation have been implicated in fine-tuning the expression of Gr 1 7 transcripts. Here, we investigated Gr promoter 1 7 methylation and Gr 1 7 expression in adult rats exposed to either acute or chronic stress paradigms. A strong negative correlation was observed between the sum of promoter-wide methylation levels and Gr 1 7 transcript levels, independent of the stressor. Methylation of individual sites did not, however, correlate with transcript levels. This suggested that promoter 1 7 was directly regulated by promoter-wide DNA methylation. Although acute stress increased Ngfi-a expression in the hypothalamic paraventricular nucleus (PVN), Gr 1 7 transcript levels remained unaffected despite low methylation levels. Acute stress had little effect on these low methylation levels, except at four hippocampal CpGs. Chronic stress altered the corticosterone response to an acute stressor. In the adrenal and pituitary glands, but not in the brain, this was accompanied by an increase in methylation levels in orchestrated clusters rather than individual CpGs. PVN methylation levels, unaffected by acute or chronic stress, were significantly more variable within- than between-groups, suggesting that they were instated probably during the perinatal period and represent a pre-established trait. Thus, in addition to the known perinatal programming, the Gr 1 7 promoter is epigenetically regulated by chronic stress in adulthood, and retains promoter-wide tissue-specific plasticity. Differences in methylation susceptibility between the PVN in the perinatal period and the peripheral HPA axis tissues in adulthood may represent an important "trait" vs. "state" regulation of the Gr gene.

  3. The Pro-inflammatory Effects of Glucocorticoids in the Brain

    PubMed Central

    Duque, Erica de Almeida; Munhoz, Carolina Demarchi

    2016-01-01

    Glucocorticoids are a class of steroid hormones derived from cholesterol. Their actions are mediated by the glucocorticoid and mineralocorticoid receptors, members of the superfamily of nuclear receptors, which, once bound to their ligands, act as transcription factors that can directly modulate gene expression. Through protein–protein interactions with other transcription factors, they can also regulate the activity of many genes in a composite or tethering way. Rapid non-genomic signaling was also demonstrated since glucocorticoids can act through membrane receptors and activate signal transduction pathways, such as protein kinases cascades, to modulate other transcriptions factors and activate or repress various target genes. By all these different mechanisms, glucocorticoids regulate numerous important functions in a large variety of cells, not only in the peripheral organs but also in the central nervous system during development and adulthood. In general, glucocorticoids are considered anti-inflammatory and protective agents due to their ability to inhibit gene expression of pro-inflammatory mediators and other possible damaging molecules. Nonetheless, recent studies have uncovered situations in which these hormones can act as pro-inflammatory agents depending on the dose, chronicity of exposure, and the structure/organ analyzed. In this review, we will provide an overview of the conditions under which these phenomena occur, a discussion that will serve as a basis for exploring the mechanistic foundation of glucocorticoids pro-inflammatory gene regulation in the brain. PMID:27445981

  4. The Ups and Downs of Glucocorticoid Signaling | Center for Cancer Research

    Cancer.gov

    Glucocorticoids are steroids that react to stress by regulating inflammation and controlling metabolism. Because of their anti-inflammatory and immunosuppressive properties, corticosteroids are among the most frequently prescribed drugs. Glucocorticoids are often used to treat arthritis and autoimmune diseases and are also given in combination with other drugs to treat

  5. Central glucocorticoid receptors regulate the upregulation of spinal cannabinoid-1 receptors after peripheral nerve injury in rats.

    PubMed

    Wang, Shuxing; Lim, Grewo; Mao, Ji; Sung, Backil; Yang, Liling; Mao, Jianren

    2007-09-01

    Previous studies have shown that peripheral nerve injury upregulated both glucocorticoid receptors (GR) and cannabinoid-1 receptors (CB1R) within the spinal cord dorsal horn in rats. However, the relationship between the expression of spinal GR and CB1R after nerve injury remains unclear. Here, we examined the hypothesis that the upregulation of spinal CB1R induced by chronic constriction nerve injury (CCI) in rats would be regulated by spinal GR. CCI induced the upregulation of spinal CB1R primarily within the ipsilateral spinal cord dorsal horn as revealed by Western blot and immunohistochemistry. The expression of CB1R in CCI rats was substantially attenuated by intrathecal treatment with either the GR antagonist RU38486 or a GR antisense oligonucleotide given twice daily for postoperative day 1-6, whereas the expression of spinal CB1R was enhanced following intrathecal administration of a GR sense oligonucleotide twice daily for postoperative day 1-6. Furthermore, the upregulation of spinal CB1R after nerve injury was prevented in adrenalectomized rats, which was at least partially restored with the intrathecal administration of an exogenous GR agonist dexamethasone, indicating that corticosteroids (endogenous GR agonists) were critical to spinal GR actions. Since the development of neuropathic pain behaviors in CCI rats was attenuated by either RU38486 or a GR antisense oligonucleotide, these results suggest that CB1R is a downstream target for spinal GR actions contributory to the mechanisms of neuropathic pain.

  6. Glucocorticoid receptor ligand binding in monocytic cells using a microplate assay.

    PubMed

    Jansen, J; Uitdehaag, B; Koper, J W; van Den Berg, T K

    1999-01-01

    Glucocorticoids have profound effects on macrophage function and are widely used as anti-inflammatory drugs. Glucocorticoids receptor (GR) ligand binding capacity is a major determinant of cellular glucocorticoid sensitivity. The number and affinity of GR can be measured in a whole cell binding assay using (3)H-dexamethasone. Here, we describe a rapid and simple microplate assay for GR measurement using the human promonocytic cell line THP-1. Copyright 2000 S. Karger AG, Basel.

  7. Prolonged administration of pyridostigmine impairs neuromuscular function with and without down-regulation of acetylcholine receptors.

    PubMed

    Richtsfeld, Martina; Yasuhara, Shingo; Fink, Heidrun; Blobner, Manfred; Martyn, J A Jeevendra

    2013-08-01

    The acetylcholinesterase inhibitor, pyridostigmine, is prophylactically administered to mitigate the toxic effects of nerve gas poisoning. The authors tested the hypothesis that prolonged pyridostigmine administration can lead to neuromuscular dysfunction and even down-regulation of acetylcholine receptors. Pyridostigmine (5 or 25 mg·kg·day) or saline was continuously administered via osmotic pumps to rats, and infused for either 14 or 28 days until the day of neuromuscular assessment (at day 14 or 28), or discontinued 24 h before neuromuscular assessment. Neurotransmission and muscle function were examined by single-twitch, train-of-four stimulation and 100-Hz tetanic stimulation. Sensitivity to atracurium and acetylcholine receptor number (quantitated by I-α-bungarotoxin) provided additional measures of neuromuscular integrity. Specific tetanic tensions (Newton [N]/muscle weight [g]) were significantly (P < 0.05) decreased at 14 (10.3 N/g) and 28 (11.1 N/g) days of 25 mg·kg·day pyridostigmine compared with controls (13.1-13.6 N/g). Decreased effective dose (0.81-1.05 vs. 0.16-0.45 mg/kg; P < 0.05) and decreased plasma concentration (3.02-3.27 vs. 0.45-1.37 μg/ml; P < 0.05) of atracurium for 50% paralysis (controls vs. 25 mg·kg·day pyridostigmine, respectively), irrespective of discontinuation of pyridostigmine, confirmed the pyridostigmine-induced altered neurotransmission. Pyridostigmine (25 mg·kg·day) down-regulated acetylcholine receptors at 28 days. Prolonged administration of pyridostigmine (25 mg·kg·day) leads to neuromuscular impairment, which can persist even when pyridostigmine is discontinued 24 h before assessment of neuromuscular function. Pyridostigmine has the potential to down-regulate acetylcholine receptors, but induces neuromuscular dysfunction even in the absence of receptor changes.

  8. Disruption of histone modification and CARM1 recruitment by arsenic represses transcription at glucocorticoid receptor-regulated promoters.

    PubMed

    Barr, Fiona D; Krohmer, Lori J; Hamilton, Joshua W; Sheldon, Lynn A

    2009-08-26

    Chronic exposure to inorganic arsenic (iAs) found in the environment is one of the most significant and widespread environmental health risks in the U.S. and throughout the world. It is associated with a broad range of health effects from cancer to diabetes as well as reproductive and developmental anomalies. This diversity of diseases can also result from disruption of metabolic and other cellular processes regulated by steroid hormone receptors via aberrant transcriptional regulation. Significantly, exposure to iAs inhibits steroid hormone-mediated gene activation. iAs exposure is associated with disease, but is also used therapeutically to treat specific cancers complicating an understanding of iAs action. Transcriptional activation by steroid hormone receptors is accompanied by changes in histone and non-histone protein post-translational modification (PTM) that result from the enzymatic activity of coactivator and corepressor proteins such as GRIP1 and CARM1. This study addresses how iAs represses steroid receptor-regulated gene transcription. PTMs on histones H3 and H4 at the glucocorticoid receptor (GR)-activated mouse mammary tumor virus (MMTV) promoter were identified by chromatin immunoprecipitation analysis following exposure to steroid hormone+/-iAs. Histone H3K18 and H3R17 amino acid residues had significantly different patterns of PTMs after treatment with iAs. Promoter interaction of the coactivator CARM1 was disrupted, but the interaction of GRIP1, a p160 coactivator through which CARM1 interacts with a promoter, was intact. Over-expression of CARM1 was able to fully restore and GRIP1 partially restored iAs-repressed transcription indicating that these coactivators are functionally associated with iAs-mediated transcriptional repression. Both are essential for robust transcription at steroid hormone regulated genes and both are associated with disease when inappropriately expressed. We postulate that iAs effects on CARM1 and GRIP1 may underlie some

  9. Ginsenoside Rg1 exerts synergistic anti-inflammatory effects with low doses of glucocorticoids in vitro.

    PubMed

    Song, Yanqin; Zhao, Feng; Zhang, Leiming; Du, Yuan; Wang, Tian; Fu, Fenghua

    2013-12-01

    Glucocorticoids (GCs) are usually used to treat inflammatory diseases. However, they cause severe and irreversible side effects, which limit the use of these compounds. Ginsenoside Rg1 had been demonstrated to possess anti-inflammatory and anti-cancer effects. The present study was designed to investigate whether Rg1 exhibits synergistic anti-inflammatory effects when combined with glucocorticoids. After stimulated by lipopolysaccharide (LPS), murine macrophagic RAW264.7 cells were treated with Rg1, corticosterone (Cort) or Rg1 and Cort. Then nitric oxide (NO), tumor necrosis factor-α (TNF-α) and glucocorticoid receptor (GR) expression were measured. The results showed that Rg1 or Cort could reduce the production of NO and TNF-α, and Rg1 dose-dependently up-regulated GR expression, while Cort dose-dependently down-regulated GR expression. The combination of low concentrations of Rg1 with Cort, which alone could not markedly inhibit the release of inflammatory factors, inhibited the secretion of NO and TNF-α in LPS-stimulated RAW264.7 macrophage cells, and up-regulated the expression of GR. The findings suggested Rg1 can synergize with glucocorticoid to enhance its anti-inflammatory effect. © 2013.

  10. Cortisol Induces Reactive Oxygen Species Through a Membrane Glucocorticoid Receptor in Rainbow Trout Myotubes.

    PubMed

    Espinoza, Marlen B; Aedo, Jorge E; Zuloaga, Rodrigo; Valenzuela, Cristian; Molina, Alfredo; Valdés, Juan A

    2017-04-01

    Cortisol is an essential regulator of neuroendocrine stress responses in teleosts. Cortisol predominantly affects target tissues through the genomic pathway, which involves interacting with cytoplasmic glucocorticoid receptors, and thereby, modulating stress-response gene expressions. Cortisol also produces rapid effects via non-genomic pathways, which do not involve gene transcription. Although cortisol-mediated genomic pathways are well documented in teleosts, non-genomic pathways are not fully understood. Moreover, no studies have focused on the contribution of non-genomic cortisol pathways in compensatory stress responses in fish. In this study, rainbow trout (Oncorhynchus mykiss) skeletal myotubes were stimulated with physiological concentrations of cortisol and cortisol-BSA, a membrane-impermeable agent, resulting in an early induction of reactive oxygen species (ROS). This production was not suppressed by transcription or translation inhibitors, suggesting non-genomic pathway involvement. Moreover, myotube preincubation with RU486 and NAC completely suppressed cortisol- and cortisol-BSA-induced ROS production. Subcellular fractionation analysis revealed the presence of cell membrane glucocorticoid receptors. Finally, cortisol-BSA induced a significant increase in ERK1/2 and CREB phosphorylation, as well as in CREB-dependent transcriptional activation of the pgc1a gene expression. The obtained results strongly suggest that cortisol acts through a non-genomic glucocorticoid receptor-mediated pathway to induce ROS production and contribute to ERK/CREB/PGC1-α signaling pathway activation as stress compensation mechanisms. J. Cell. Biochem. 118: 718-725, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  11. Chronic stress triggers social aversion via glucocorticoid receptor in dopaminoceptive neurons.

    PubMed

    Barik, Jacques; Marti, Fabio; Morel, Carole; Fernandez, Sebastian P; Lanteri, Christophe; Godeheu, Gérard; Tassin, Jean-Pol; Mombereau, Cédric; Faure, Philippe; Tronche, François

    2013-01-18

    Repeated traumatic events induce long-lasting behavioral changes that are key to organism adaptation and that affect cognitive, emotional, and social behaviors. Rodents subjected to repeated instances of aggression develop enduring social aversion and increased anxiety. Such repeated aggressions trigger a stress response, resulting in glucocorticoid release and activation of the ascending dopamine (DA) system. We bred mice with selective inactivation of the gene encoding the glucocorticoid receptor (GR) along the DA pathway, and exposed them to repeated aggressions. GR in dopaminoceptive but not DA-releasing neurons specifically promoted social aversion as well as dopaminergic neurochemical and electrophysiological neuroadaptations. Anxiety and fear memories remained unaffected. Acute inhibition of the activity of DA-releasing neurons fully restored social interaction in socially defeated wild-type mice. Our data suggest a GR-dependent neuronal dichotomy for the regulation of emotional and social behaviors, and clearly implicate GR as a link between stress resiliency and dopaminergic tone.

  12. The Ups and Downs of Glucocorticoid Signaling | Center for Cancer Research

    Cancer.gov

    Glucocorticoids are steroids that react to stress by regulating inflammation and controlling metabolism. Because of their anti-inflammatory and immunosuppressive properties, corticosteroids are among the most frequently prescribed drugs. Glucocorticoids are often used to treat arthritis and autoimmune diseases and are also given in combination with other drugs to treat cancers—such as leukemias and lymphomas—or to alleviate side effects from chemotherapy and radiation. In humans, a glucocorticoid called cortisol is released from the adrenal gland approximately every hour to send signals to cells throughout the body. This pulsed release of hormone is called ultradian secretion.  

  13. Identification of hormone-interacting amino acid residues within the steroid-binding domain of the glucocorticoid receptor in relation to other steroid hormone receptors

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Carlstedt-Duke, J.; Stroemstedt, P.E.; Persson, B.

    1988-05-15

    Purified rat liver glucocorticoid receptor was covalently charged with (/sup 3/H)glucocorticoid by photoaffinity labeling (UV irradiation of (/sup 3/H)triamcinolone acetonide-glucocorticoid receptor) or affinity labeling (incubation with (/sup 3/H)dexamethasone mesylate). After labeling, separate samples of the denatured receptor were cleaved with trypsin (directly or after prior succinylation), chymotrypsin, and cyanogen bromide. Labeled residues in the peptides obtained were identified by radiosequence analysis. The peaks of radioactivity corresponded to Met-622 and Cys-754 after photoaffinity labeling with (/sup 3/H)triamcinolone acetonide and Cys-656 after affinity labeling with (/sup 3/H)dexamethasone mesylate. The labeled residues are all positioned within hydrophobic segments of the steroid-binding domain. Themore » patterns of hydropathy and secondary structure for the glucocorticoid receptor are highly similar to those for the progestin receptor and similar but less so to those for the estrogen receptor and to those for c-erb A.« less

  14. Glucocorticoid and calcitonin receptor expression in central giant cell lesions: implications for therapy.

    PubMed

    Nogueira, R L M; Faria, M H G; Osterne, R L V; Cavalcante, R B; Ribeiro, R A; Rabenhorst, S H B

    2012-08-01

    Central giant cell lesion is an uncommon benign jaw lesion, with uncertain aetiology, and variable clinical behaviour. Studies of molecular markers may help to understand the nature and behaviour of this lesion, and eventually may represent a target for pharmacological approaches to treatment. The aim of this study was to analyse the expression of glucocorticoid and calcitonin receptors in central giant cell lesions before and after treatment with intralesional steroid. Paraffin-embedded blocks from patients who underwent treatment with intralesional triamcinolone hexacetonide injections were stained immunohistochemically. Biological material from patients who underwent a surgical procedure after treatment were tested immunohistochemically. 18 cases (9 aggressive and 9 non-aggressive) were included. The difference in calcitonin receptor expression was not statistically significant between the aggressive and non-aggressive lesions and between the patients with a good response and those with a moderate/negative response to treatment. Glucocorticoid receptor expression in the multinucleated giant cells was higher in patients with a good response. It can be postulated that immunohistochemical staining for glucocorticoid receptors may provide a tool for selecting the therapeutic strategy. An H-score greater than 48 for glucocorticoid receptors in multinucleated giant cells predicted a good response in this study. Copyright © 2012 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

  15. Glucocorticoid receptor polymorphism in obesity and glucose homeostasis.

    PubMed

    Majer-Łobodzińska, Agnieszka; Adamiec-Mroczek, Joanna

    2017-01-01

    Glucocorticoid receptor (GR) activity plays a significant role in the etiology of obesity and is essential for glucose homeostasis, the development of hyperinsulinaemia and subsequent increased fat deposition. Several polymorphisms in the GR gene have been described, and at least three of them seem to be associated with altered glucocorticoid sensitivity and changes in glucose homeostasis, and other metabolic parameters. The N363S polymorphism has been associated with increased sensitivity to glucocorticoides, increased insulin response to dexamethasone and increased plasma glucose level. BclI polymorphism is associated with increased abdominal obesity, hyperinsulinaemia and increased insulin resistance. Another polymorphism, ER22/23EK, in contrast to the others, is associated with relative resistance to glucocoricides actions and more beneficial metabolic profile-lower insulin resistance level, decreased lower cardiovascular risk and subseuent prolongation of life time. More research is still needed to understand the mechanisms behind these associations at the molecular level.

  16. Modulation of central glucocorticoid receptors in short- and long-term experimental hyperthyroidism.

    PubMed

    Nikolopoulou, Elena; Mytilinaios, Dimitrios; Calogero, Aldo E; Kamilaris, Themis C; Troupis, Theodore; Chrousos, George P; Johnson, Elizabeth O

    2015-08-01

    Hyperthyroidism is associated with a significant increase in circulating glucocorticoid levels and hyperactivity of the hypothalamic-pituitary-adrenal (HPA) axis. The aim of this study was to examine whether the HPA axis hyperactivity observed in hyperthyroidism may be explained by a disturbed feedback inhibition of endogenous glucocorticoids through two specific intracellular receptors in the brain: the high affinity mineralocorticoid receptor (MR) and the lower affinity glucocorticoid receptor (GR). Cytosolic receptor binding and gene expression was assessed in rats with short (7 days) and long standing (60 days) eu- and hyperthyroidism. Glucocorticoid receptor number and binding affinity (Kd) in the hippocampus were measured using [(3)H2]-dexamethasone radioreceptor assay. In situ hybridization was employed to examine the effects of hyperthyroidism on the GR and MR mRNA levels in the hippocampus and the pituitary. Both short- and long-term hyperthyroid rats showed pronounced reduction in the concentration of cytosolic GR in the hippocampus, without changes in binding affinity or changes in GR expression. In contrast, GR mRNA in the pituitary increased after 7 days and decreased after 60 days of thyroxin treatment. MR mRNA was moderately affected. Hyperthyroidism is associated with significant decreases in hippocampal GR levels supporting the hypothesis that hyperactivity of the HPA axis observed in experimentally induced hyperthyroidism may be attributed, at least in part, to decreased negative feedback at the level of the hippocampus. These findings further support the notion that a central locus is principally responsible for the hyperactivity of the HPA axis observed in hyperthyroidism.

  17. The down-regulation of the mitogenic fibrinogen receptor (MFR) in serum-containing medium does not occur in defined medium.

    PubMed

    Levesque, J P; Hatzfeld, A; Domart, I; Hatzfeld, J

    1990-02-01

    Normal human hemopoietic cells such as early bone marrow progenitors, or lymphoma-derived cell lines such as Raji or JM cells, possess a low-affinity receptor specific for fibrinogen. This receptor triggers a mitogenic effect. It differs from the glycoprotein IIb-IIIa which is involved in fibrinogen-induced platelet aggregation. We demonstrate here that this mitogenic fibrinogen receptor (MFR) can be internalized or reexpressed, depending on culture conditions. Internalization was temperature-dependent. At 37 degrees C in the presence of cycloheximide or actinomycin D, the half-life of cell surface MFRs was 2 h, independent of receptor occupancy. Binding of fibrinogen to the MFR resulted in a down-regulation which was fibrinogen dose-dependent. This occurred in serum-supplemented medium but not in defined medium supplemented with fatty acids. Reexpression of MFRs could be induced in 28 to 42 h by serum removal. The down-regulation of mitogenic receptors in plasma or serum could explain why normal cells do not proliferate in the peripheral blood.

  18. Role of Prefrontal Cortex Glucocorticoid Receptors in Stress and Emotion

    PubMed Central

    McKlveen, Jessica M.; Myers, Brent; Flak, Jonathan N.; Bundzikova, Jana; Solomon, Matia B.; Seroogy, Kim B.; Herman, James P.

    2013-01-01

    Background Stress-related disorders (e.g., depression) are associated with hypothalamic-pituitary-adrenocortical axis dysregulation and prefrontal cortex (PFC) dysfunction, suggesting a functional link between aberrant prefrontal corticosteroid signaling and mood regulation. Methods We used a virally mediated knockdown strategy (short hairpin RNA targeting the glucocorticoid receptor [GR]) to attenuate PFC GR signaling in the rat PFC. Adult male rats received bilateral microinjections of vector control or short hairpin RNA targeting the GR into the prelimbic (n = 44) or infralimbic (n = 52) cortices. Half of the animals from each injection group underwent chronic variable stress, and all were subjected to novel restraint. The first 2 days of chronic variable stress were used to assess depression- and anxiety-like behavior in the forced swim test and open field. Results The GR knockdown confined to the infralimbic PFC caused acute stress hyper-responsiveness, sensitization of stress responses after chronic variable stress, and induced depression-like behavior (increased immobility in the forced swim test). Knockdown of GR in the neighboring prelimbic PFC increased hypothalamic-pituitary-adrenocortical axis responses to acute stress and caused hyper-locomotion in the open field, but did not affect stress sensitization or helplessness behavior. Conclusions The data indicate a marked functional heterogeneity of glucocorticoid action in the PFC and highlight a prominent role for the infralimbic GR in appropriate stress adaptation, emotional control, and mood regulation. PMID:23683655

  19. Glucocorticoids facilitate the transcription from the human cytomegalovirus major immediate early promoter in glucocorticoid receptor- and nuclear factor-I-like protein-dependent manner

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Inoue-Toyoda, Maki; Kato, Kohsuke; Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba 305-8575

    Human cytomegalovirus (HCMV) is a common and usually asymptomatic virus agent in healthy individuals. Initiation of HCMV productive infection depends on expression of the major immediate early (MIE) genes. The transcription of HCMV MIE genes is regulated by a diverse set of transcription factors. It was previously reported that productive HCMV infection is triggered probably by elevation of the plasma hydroxycorticoid level. However, it is poorly understood whether the transcription of MIE genes is directly regulated by glucocorticoid. Here, we found that the dexamethasone (DEX), a synthetic glucocorticoid, facilitates the transcription of HCMV MIE genes through the MIE promoter andmore » enhancer in a glucocorticoid receptor (GR)-dependent manner. By competitive EMSA and reporter assays, we revealed that an NF-I like protein is involved in DEX-mediated transcriptional activation of the MIE promoter. Thus, this study supports a notion that the increased level of hydroxycorticoid in the third trimester of pregnancy reactivates HCMV virus production from the latent state. - Highlights: • DEX facilitates the transcription from the HCMV MIE promoter. • GR is involved in DEX-dependent transcription from the HCMV MIE promoter. • A 17 bp repeat is responsible for the HCMV MIE promoter activation by DEX. • An NF-I-like protein is involved in the HCMV MIE promoter activation by DEX.« less

  20. Quantitative Impact of Plasma Clearance and Down-regulation on GLP-1 Receptor Molecular Imaging.

    PubMed

    Zhang, Liang; Thurber, Greg M

    2016-02-01

    Quantitative molecular imaging of beta cell mass (BCM) would enable early detection and treatment monitoring of type 1 diabetes. The glucagon-like peptide-1 (GLP-1) receptor is an attractive target due to its beta cell specificity and cell surface location. We quantitatively investigated the impact of plasma clearance and receptor internalization on targeting efficiency in healthy B6 mice. Four exenatide-based probes were synthesized that varied in molecular weight, binding affinity, and plasma clearance. The GLP-1 receptor internalization rate and in vivo receptor expression were quantified. Receptor internalization (54,000 receptors/cell in vivo) decreased significantly within minutes, reducing the benefit of a slower-clearing agent. The multimers and albumin binding probes had higher kidney and liver uptake, respectively. Slow plasma clearance is beneficial for GLP-1 receptor peptide therapeutics. However, for exendin-based imaging of islets, down-regulation of the GLP-1 receptor and non-specific background uptake result in a higher target-to-background ratio for fast-clearing agents.

  1. Maternal licking regulates hippocampal glucocorticoid receptor transcription through a thyroid hormone–serotonin–NGFI-A signalling cascade

    PubMed Central

    Hellstrom, Ian C.; Dhir, Sabine K.; Diorio, Josie C.; Meaney, Michael J.

    2012-01-01

    Variations in parental care direct phenotypic development across many species. Variations in maternal pup licking/grooming (LG) in the rat regulate the development of individual differences in hypothalamic–pituitary–adrenal responses to stress. The adult offspring of mothers that show an increased frequency of pup LG have increased hippocampal glucocorticoid receptor (GR) expression and more modest pituitary–adrenal responses to stress. This parental effect is mediated by the epigenetic programming of a GR exon 1 promoter (exon 17) through the binding of the transcription factor nerve growth factor-inducible factor A (NGFI-A). In this paper, we report that: (i) the association of NGFI-A with the exon 17 GR promoter is dynamically regulated by mother–pup interactions; (ii) this effect is mimicked by artificial tactile stimulation comparable to that provided by pup LG; (iii) that serotonin (5-HT) induces an NGFI-A-dependent increase in GR transcription in hippocampal neurons and NGFI-A overexpression is sufficient for this effect; and (iv) that thyroid hormones and 5-HT are key mediators of the effects of pup LG and tactile stimulation on NGFI-A binding to the exon 17 GR promoter in hippocampus. These findings suggest that pup LG directly activates 5-HT systems to initiate intracellular signalling pathways in the hippocampus that regulate GR transcription. PMID:22826348

  2. A facile, branched DNA assay to quantitatively measure glucocorticoid receptor auto-regulation in T-cell acute lymphoblastic leukemia

    PubMed Central

    Schwartz, Jason R.; Sarvaiya, Purvaba J.; Leiva, Lily E.; Velez, Maria C.; Singleton, Tammuella C.; Yu, Lolie C.; Vedeckis, Wayne V.

    2012-01-01

    Glucocorticoid (GC) steroid hormones are used to treat acute lymphoblastic leukemia (ALL) because of their pro-apoptotic effects in hematopoietic cells. However, not all leukemia cells are sensitive to GC, and no assay to stratify patients is available. In the GC-sensitive T-cell ALL cell line CEM-C7, auto-up-regulation of RNA transcripts for the glucocorticoid receptor (GR) correlates with increased apoptotic response. This study aimed to determine if a facile assay of GR transcript levels might be promising for stratifying ALL patients into hormone-sensitive and hormone-resistant populations. The GR transcript profiles of various lymphoid cell lines and 4 bone marrow samples from patients with T-cell ALL were analyzed using both an optimized branched DNA (bDNA) assay and a real-time quantitative reverse transcription-polymerase chain reaction assay. There were significant correlations between both assay platforms when measuring total GR (exon 5/6) transcripts in various cell lines and patient samples, but not for a probe set that detects a specific, low abundance GR transcript (exon 1A3). Our results suggest that the bDNA platform is reproducible and precise when measuring total GR transcripts and, with further development, may ultimately offer a simple clinical assay to aid in the prediction of GC-sensitivity in ALL patients. PMID:22739263

  3. A role for glucocorticoids in stress-impaired reproduction: beyond the hypothalamus and pituitary.

    PubMed

    Whirledge, Shannon; Cidlowski, John A

    2013-12-01

    In addition to the well-characterized role of the sex steroid receptors in regulating fertility and reproduction, reproductive events are also mediated by the hypothalamic-pituitary-adrenal axis in response to an individual's environment. Glucocorticoid secretion in response to stress contributes to the well-characterized suppression of the hypothalamic-pituitary-gonadal axis through central actions in the hypothalamus and pituitary. However, both animal and in vitro studies indicate that other components of the reproductive system are also regulated by glucocorticoids. Furthermore, in the absence of stress, it appears that homeostatic glucocorticoid signaling plays a significant role in reproduction and fertility in all tissues comprising the hypothalamic-pituitary-gonadal axis. Indeed, as central regulators of the immune response, glucocorticoids are uniquely poised to integrate an individual's infectious, inflammatory, stress, nutritional, and metabolic status through glucocorticoid receptor signaling in target tissues. Endocrine signaling between tissues regulating the immune and stress response and those determining reproductive status provides an evolutionary advantage, facilitating the trade-off between reproductive investment and offspring fitness. This review focuses on the actions of glucocorticoids in tissues important for fertility and reproduction, highlighting recent studies that show glucocorticoid signaling plays a significant role throughout the hypothalamic-pituitary-gonadal axis and characterizing these effects as permissive or inhibitory in terms of facilitating reproductive success.

  4. Down-regulation of pituitary receptors for luteinizing hormone-releasing hormone (LH-RH) in rats by LH-RH antagonist Cetrorelix.

    PubMed Central

    Halmos, G; Schally, A V; Pinski, J; Vadillo-Buenfil, M; Groot, K

    1996-01-01

    Antagonists of luteinizing hormone-releasing hormone (LH-RH), unlike the LH-RH agonists, suppress gonadotropins and sex steroid secretion immediately after administration, without initial stimulatory effects. [Ac-D-Nal(2)1,D-Ph(4Cl)2,D-Pal(3)3,D-Cit6,D-Ala10]LH-R H (SB-75; Cetrorelix) is a modern, potent antagonistic analog of LH-RH. In this study, the binding characteristics of receptors for LH-RH in membrane fractions from rat anterior pituitaries were investigated after a single injection of Cetrorelix at a dose of 100 microg per rat. To determine whether the treatment with Cetrorelix can affect the concentration of measurable LH-RH binding sites, we applied an in vitro method to desaturate LH-RH receptors by chaotropic agents such as manganous chloride (MnCl2) and ammonium thiocyanate (NH4SCN). Our results show that the percentages of occupied LH-RH receptors at 1, 3, and 6 h after administration of Cetrorelix were approximately 28%, 14%, and 10%, respectively, of total receptors. At later time intervals, we could not detect occupied LH-RH binding sites. Ligand competition assays, following in vitro desaturation, demonstrated that rat pituitary LH-RH receptors were significantly (P < 0.01) down-regulated for at least 72 h after administration of Cetrorelix. The lowest receptor concentration was found 3-6 h after Cetrorelix treatment and a recovery in receptor number began within approximately 24 h. The down-regulation of LH-RH binding sites induced by Cetrorelix was accompanied by serum LH and testosterone suppression. Higher LH-RH receptor concentrations coincided with elevated serum hormone levels at later time intervals. Our results indicate that administration of LH-RH antagonist Cetrorelix produces a marked down-regulation of pituitary receptors for LH-RH and not merely an occupancy of binding sites. PMID:8637885

  5. Ultradian hormone stimulation induces glucocorticoid receptor-mediated pulses of gene transcription.

    PubMed

    Stavreva, Diana A; Wiench, Malgorzata; John, Sam; Conway-Campbell, Becky L; McKenna, Mervyn A; Pooley, John R; Johnson, Thomas A; Voss, Ty C; Lightman, Stafford L; Hager, Gordon L

    2009-09-01

    Studies on glucocorticoid receptor (GR) action typically assess gene responses by long-term stimulation with synthetic hormones. As corticosteroids are released from adrenal glands in a circadian and high-frequency (ultradian) mode, such treatments may not provide an accurate assessment of physiological hormone action. Here we demonstrate that ultradian hormone stimulation induces cyclic GR-mediated transcriptional regulation, or gene pulsing, both in cultured cells and in animal models. Equilibrium receptor-occupancy of regulatory elements precisely tracks the ligand pulses. Nascent RNA transcripts from GR-regulated genes are released in distinct quanta, demonstrating a profound difference between the transcriptional programs induced by ultradian and constant stimulation. Gene pulsing is driven by rapid GR exchange with response elements and by GR recycling through the chaperone machinery, which promotes GR activation and reactivation in response to the ultradian hormone release, thus coupling promoter activity to the naturally occurring fluctuations in hormone levels. The GR signalling pathway has been optimized for a prompt and timely response to fluctuations in hormone levels, indicating that biologically accurate regulation of gene targets by GR requires an ultradian mode of hormone stimulation.

  6. Prenatal glucocorticoid programming of brain corticosteroid receptors and corticotrophin-releasing hormone: possible implications for behaviour.

    PubMed

    Welberg, L A; Seckl, J R; Holmes, M C

    2001-01-01

    Glucocorticoids may underlie the association between low birth weight and adult disorders such as hypertension, type 2 diabetes and affective dysfunction. We investigated the behavioural and molecular consequences of two paradigms of prenatal dexamethasone administration in rats. Rats received dexamethasone (100 microg/kg per day) throughout pregnancy (DEX1-3), in the last third of pregnancy only (DEX3) or vehicle. Both dexamethasone treatments reduced birth weight, only DEX1-3 offspring had reduced body weight in adulthood. In adult offspring, both prenatal dexamethasone paradigms reduced exploratory behaviour in an open field. In contrast, only DEX3 reduced exploration in an elevated plus-maze and impaired behavioural responses and learning in a forced-swim test. This behavioural inhibition may reflect increased baseline corticotrophin-releasing hormone mRNA levels (30% higher) in the central nucleus of the amygdala in both dexamethasone-exposed groups. Adult DEX3 offspring also showed increased corticotrophin-releasing hormone mRNA with unaltered glucocorticoid receptor mRNA in the hypothalamic paraventricular nucleus and reduced hippocampal glucocorticoid- and mineralocorticoid receptor mRNA expression, suggesting reduced hippocampal sensitivity to glucocorticoid suppression of the stress axis. In contrast, DEX1-3 rats had no changes in hippocampal corticosteroid receptors, but showed increased mRNA levels for both receptors in the basolateral nucleus of the amygdala. From this data we suggest that prenatal glucocorticoid exposure programs behavioural inhibition perhaps via increased amygdalar corticotrophin-releasing hormone levels, while DEX3 also impairs coping and learning in aversive situations, possibly via altered hippocampal corticosteroid receptor levels. Overexposure to glucocorticoids, especially late in gestation, may explain the link between reduced early growth and adult affective dysfunction.

  7. Alternative dimerization interfaces in the glucocorticoid receptor-α ligand binding domain.

    PubMed

    Bianchetti, Laurent; Wassmer, Bianca; Defosset, Audrey; Smertina, Anna; Tiberti, Marion L; Stote, Roland H; Dejaegere, Annick

    2018-04-30

    Nuclear hormone receptors (NRs) constitute a large family of multi-domain ligand-activated transcription factors. Dimerization is essential for their regulation, and both DNA binding domain (DBD) and ligand binding domain (LBD) are implicated in dimerization. Intriguingly, the glucocorticoid receptor-α (GRα) presents a DBD dimeric architecture similar to that of the homologous estrogen receptor-α (ERα), but an atypical dimeric architecture for the LBD. The physiological relevance of the proposed GRα LBD dimer is a subject of debate. We analyzed all GRα LBD homodimers observed in crystals using an energetic analysis based on the PISA and on the MM/PBSA methods and a sequence conservation analysis, using the ERα LBD dimer as a reference point. Several dimeric assemblies were observed for GRα LBD. The assembly generally taken to be physiologically relevant showed weak binding free energy and no significant residue conservation at the contact interface, while an alternative homodimer mediated by both helix 9 and C-terminal residues showed significant binding free energy and residue conservation. However, none of the GRα LBD assemblies found in crystals are as stable or conserved as the canonical ERα LBD dimer. GRα C-terminal sequence (F-domain) forms a steric obstacle to the canonical dimer assembly in all available structures. Our analysis calls for a re-examination of the currently accepted GRα homodimer structure and experimental investigations of the alternative architectures. This work questions the validity of the currently accepted architecture. This has implications for interpreting physiological data and for therapeutic design pertaining to glucocorticoid research. Copyright © 2018. Published by Elsevier B.V.

  8. [Effect of paeoniflorin on level of glucocorticoid receptor of peripheral blood monocytes in rats of collagen-induced arthritis].

    PubMed

    Yi, Jian-Feng

    2014-03-01

    The study is to explore the effect of paeoniflorin on the level of glucocorticoid receptor, including glucocorticoid receptor-alpha (GCRalpha) and glucocorticoid receptor-beta (GCRbeta), of peripheral blood mononuclear cells (PBMCs) in rats of collagen-induced arthritis (CIA). CIA is induced in Wistar rats by an intradermal injection of bovine type II collagen emulsified with complete adjuvant. From the 14th day after primary immunization, the CIA rats were intragastrically administered paeoniflorin 25, 50 and 100 mg x kg(-1) or triptolde 20 microg x kg(-1) or paeoniflorin 50 mg x kg(-1) + RU486 15 mg x kg(-1), once a day, for 28 consecutive days. After administration, apart from PF + RU486 group all experimental rats were took blood by removalling eyeball, then separated PBMCs. The level of GCRalpha, GCRbeta in PBMCs were examined by ELISA, and the mRNA expression of GCRalpha, GCRbeta was detected by RT-PCR. All rats were sacrificed and took the joint with no immunization. The expression of IL-1beta, NF-kappaB p65, TNF-alpha, PGE2 of synovial tissue was detected by immunohistochemistry. Paeoniflorin was able to inhibit the expression of IL-1beta, NF-kappaB p65, TNF-alpha, PGE2 of synovial tissue in CIA rats. While RU486, glucocorticoid receptor's blocker, could weaken the fuction of paeoniflorin. Meanwhile, paeoniflorin obviously induced the expression of GCRalpha and GCRalpha mRNA, while obviously inhibited the expression of GCRbeta and GCRbeta mRNA. These results indicat paeoniflorine suppresses inflammatory mediator production may be relating with it regulating GCR in PBMCs of CIA rats.

  9. Glucocorticoid and cytokine crosstalk: Feedback, feedforward, and co-regulatory interactions determine repression or resistance

    PubMed Central

    Shah, Suharsh; Altonsy, Mohammed O.; Gerber, Antony N.

    2017-01-01

    Inflammatory signals induce feedback and feedforward systems that provide temporal control. Although glucocorticoids can repress inflammatory gene expression, glucocorticoid receptor recruitment increases expression of negative feedback and feedforward regulators, including the phosphatase, DUSP1, the ubiquitin-modifying enzyme, TNFAIP3, or the mRNA-destabilizing protein, ZFP36. Moreover, glucocorticoid receptor cooperativity with factors, including nuclear factor-κB (NF-κB), may enhance regulator expression to promote repression. Conversely, MAPKs, which are inhibited by glucocorticoids, provide feedforward control to limit expression of the transcription factor IRF1, and the chemokine, CXCL10. We propose that modulation of feedback and feedforward control can determine repression or resistance of inflammatory gene expression toglucocorticoid. PMID:28283576

  10. Glucocorticoids and 11β-HSD1 are major regulators of intramyocellular protein metabolism

    PubMed Central

    Hassan-Smith, Zaki K; Doig, Craig L; Sherlock, Mark; Stewart, Paul M; Lavery, Gareth G

    2016-01-01

    The adverse metabolic effects of prescribed and endogenous glucocorticoid excess, ‘Cushing’s syndrome’, create a significant health burden. While skeletal muscle atrophy and resultant myopathy is a clinical feature, the molecular mechanisms underpinning these changes are not fully defined. We have characterized the impact of glucocorticoids upon key metabolic pathways and processes regulating muscle size and mass including: protein synthesis, protein degradation, and myoblast proliferation in both murine C2C12 and human primary myotube cultures. Furthermore, we have investigated the role of pre-receptor modulation of glucocorticoid availability by 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) in these processes. Corticosterone (CORT) decreased myotube area, decreased protein synthesis, and increased protein degradation in murine myotubes. This was supported by decreased mRNA expression of insulin-like growth factor (IGF1), decreased activating phosphorylation of mammalian target of rapamycin (mTOR), decreased phosphorylation of 4E binding protein 1 (4E-BP1), and increased mRNA expression of key atrophy markers including: atrogin-1, forkhead box O3a (FOXO3a), myostatin (MSTN), and muscle-ring finger protein-1 (MuRF1). These findings were endorsed in human primary myotubes, where cortisol also decreased protein synthesis and increased protein degradation. The effects of 11-dehydrocorticosterone (11DHC) (in murine myotubes) and cortisone (in human myotubes) on protein metabolism were indistinguishable from that of CORT/cortisol treatments. Selective 11β-HSD1 inhibition blocked the decrease in protein synthesis, increase in protein degradation, and reduction in myotube area induced by 11DHC/cortisone. Furthermore, CORT/cortisol, but not 11DHC/cortisone, decreased murine and human myoblast proliferative capacity. Glucocorticoids are potent regulators of skeletal muscle protein homeostasis and myoblast proliferation. Our data underscores the potential use

  11. Influences of maternal and paternal PTSD on epigenetic regulation of the glucocorticoid receptor gene in Holocaust survivor offspring.

    PubMed

    Yehuda, Rachel; Daskalakis, Nikolaos P; Lehrner, Amy; Desarnaud, Frank; Bader, Heather N; Makotkine, Iouri; Flory, Janine D; Bierer, Linda M; Meaney, Michael J

    2014-08-01

    Differential effects of maternal and paternal posttraumatic stress disorder (PTSD) have been observed in adult offspring of Holocaust survivors in both glucocorticoid receptor sensitivity and vulnerability to psychiatric disorder. The authors examined the relative influences of maternal and paternal PTSD on DNA methylation of the exon 1F promoter of the glucocorticoid receptor (GR-1F) gene (NR3C1) in peripheral blood mononuclear cells and its relationship to glucocorticoid receptor sensitivity in Holocaust offspring. Adult offspring with at least one Holocaust survivor parent (N=80) and demographically similar participants without parental Holocaust exposure or parental PTSD (N=15) completed clinical interviews, self-report measures, and biological procedures. Blood samples were collected for analysis of GR-1F promoter methylation and of cortisol levels in response to low-dose dexamethasone, and two-way analysis of covariance was performed using maternal and paternal PTSD as main effects. Hierarchical clustering analysis was used to permit visualization of maternal compared with paternal PTSD effects on clinical variables and GR-1F promoter methylation. A significant interaction demonstrated that in the absence of maternal PTSD, offspring with paternal PTSD showed higher GR-1F promoter methylation, whereas offspring with both maternal and paternal PTSD showed lower methylation. Lower GR-1F promoter methylation was significantly associated with greater postdexamethasone cortisol suppression. The clustering analysis revealed that maternal and paternal PTSD effects were differentially associated with clinical indicators and GR-1F promoter methylation. This is the first study to demonstrate alterations of GR-1F promoter methylation in relation to parental PTSD and neuroendocrine outcomes. The moderation of paternal PTSD effects by maternal PTSD suggests different mechanisms for the intergenerational transmission of trauma-related vulnerabilities.

  12. Down-regulation of angiotensin II receptor subtypes and desensitization of cyclic GMP production in neuroblastoma N1E-115 cells.

    PubMed

    Reagan, L P; Ye, X; Maretzski, C H; Fluharty, S J

    1993-01-01

    Murine neuroblastoma N1E-115 cells possess membranous receptors for the octapeptide angiotensin II (AngII) whose density is substantially increased by in vitro differentiation. Incubation of differentiated N1E-115 cells with AngII produced a rapid decrease in receptor density, but did not alter the affinity of these receptors for either 125I-AngII or the high-affinity antagonist 125I-[Sarc1,Ile8]-AngII. This apparent down-regulation was dose related with an ED50 of 1 nM, and maximal decreases of approximately 90% were obtained with 100 nM AngII. Receptor loss from differentiated cell membranes was unaffected by incubations of membranes obtained from agonist-exposed cells with non-hydrolyzable analogues of GTP for 60 min at 37 degrees C to ensure dissociation of the ligand. Partial loss of AngII receptors was apparent within 5 min of agonist exposure, whereas maximal declines were not observed until 30 min. This temporal pattern resulted from a preferential decrease in the AT1 receptor subtype during the first 5 min, followed by a decline in both AT1 and AT2 receptors with longer periods of agonist exposure. The loss of membranous receptors was reversible with partial recovery observed after 4 h, and with nearly full recovery observed 18 h after exposure of the cells to AngII. However, the long-term recovery of receptor density was blocked by the protein synthesis inhibitor, cycloheximide. The heptapeptide angiotensin III produced a similar down-regulation of receptors, and the high-affinity antagonist [Sarc1,Thr8]-AngII blocked agonist-induced down-regulation. Finally, the apparent loss of cell surface AngII receptors decreased the ability of AngII to stimulate cyclic GMP production within intact N1E-115 cells.(ABSTRACT TRUNCATED AT 250 WORDS)

  13. Efficacy of Histone Deacetylase and Estrogen Receptor Inhibition in Breast Cancer Cells Due to Concerted down Regulation of Akt

    PubMed Central

    Thomas, Scott; Thurn, K. Ted; Raha, Paromita; Chen, Stephanie; Munster, Pamela N.

    2013-01-01

    Hormonal therapy resistance remains a considerable barrier in the treatment of breast cancer. Activation of the Akt-PI3K-mTOR pathway plays an important role in hormonal therapy resistance. Our recent preclinical and clinical studies showed that the addition of a histone deacetylase inhibitor re-sensitized hormonal therapy resistant breast cancer to tamoxifen. As histone deacetylases are key regulators of Akt, we evaluated the effect of combined treatment with the histone deacetylase inhibitor PCI-24781 and tamoxifen on Akt in breast cancer cells. We demonstrate that while both histone deacetylase and estrogen receptor inhibition down regulate AKT mRNA and protein, their concerted effort results in down regulation of AKT activity with induction of cell death. Histone deacetylase inhibition exerts its effect on AKT mRNA through an estrogen receptor-dependent mechanism, primarily down regulating the most abundant isoform AKT1. Although siRNA depletion of AKT modestly induces cell death, when combined with an anti-estrogen, cytotoxicity is significantly enhanced. Thus, histone deacetylase regulation of AKT mRNA is a key mediator of this therapeutic combination and may represent a novel biomarker for predicting response to this regimen. PMID:23874830

  14. The FKBP51-Glucocorticoid Receptor Balance in Stress-Related Mental Disorders.

    PubMed

    Fries, Gabriel R; Gassen, Nils C; Schmidt, Ulrike; Rein, Theo

    2015-01-01

    The immunophilin FK506 binding protein 51 (FKBP51) has emerged as one of the most intensely investigated proteins in stress-related mental disorders. It was originally characterized as Hsp90 cochaperone and part of the receptor-chaperone heterocomplex that governs the activity of steroid receptors. It turned out that the presence of FKBP51 in this heterocomplex leads to diminished activity of the corticosteroid receptors. In particular, based on its inhibitory action on the glucocorticoid receptor (GR), FKBP51 was included in a candidate gene approach to discover gene polymorphisms that might be relevant for the development and treatment of major depression. The discovery that polymorphisms in the gene coding for FKBP51 were linked to the treatment response of depressed patients intensified the research on the role of FKBP51 in stress-related diseases worldwide. It has become evident that FKBP51 is not only a regulator of GR action, but also a GR target. The function of this ultrashort intracellular feedback loop is critically important for cellular and physiological stress regulation as it does not only calibrate the function of GR, but also the levels of FKBP51. Given the pleiotropic functions of FKBP51, its levels might be equally important for mental disorders as GR function and hence for the development of potential FKBP51 drug targets.

  15. Fatty acids activate a chimera of the clofibric acid-activated receptor and the glucocorticoid receptor.

    PubMed Central

    Göttlicher, M; Widmark, E; Li, Q; Gustafsson, J A

    1992-01-01

    Peroxisome proliferators such as clofibric acid, nafenopin, and WY-14,643 have been shown to activate PPAR (peroxisome proliferator-activated receptor), a member of the steroid nuclear receptor superfamily. We have cloned the cDNA from the rat that is homologous to that from the mouse [Issemann, I. & Green, S. (1990) Nature (London) 347, 645-650], which encodes a 97% similar protein with a particularly well-conserved putative ligand-binding domain. To search for physiologically occurring activators, we established a transcriptional transactivation assay by stably expressing in CHO cells a chimera of rat PPAR and the human glucocorticoid receptor that activates expression of the placental alkaline phosphatase reporter gene under the control of the mouse mammary tumor virus promoter. Testing of compounds related to lipid metabolism or peroxisomal proliferation revealed that 150 microM concentrations of arachidonic or linoleic acid but not of dehydroepiandrosterone, cholesterol, or 25-hydroxy-cholesterol, activate the receptor chimera. In addition, saturated fatty acids induce the reporter gene. Shortening the chain length to n = 6 or introduction of an omega-terminal carboxylic group abolished the activation potential of the fatty acid. In conclusion, the present results indicate that fatty acids can regulate gene expression mediated by a member of the steroid nuclear receptor superfamily. Images PMID:1316614

  16. Endothelial glucocorticoid receptor promoter methylation according to dexamethasone sensitivity

    PubMed Central

    Mata-Greenwood, Eugenia; Jackson, P Naomi; Pearce, William J; Zhang, Lubo

    2016-01-01

    We have previously shown that in vitro sensitivity to dexamethasone (DEX) stimulation in human endothelial cells is positively regulated by the glucocorticoid receptor (NR3C1, GR). The present study determined the role of differential GR transcriptional regulation in glucocorticoid sensitivity. We studied 25 human umbilical vein endothelial cells (HUVECs) that had been previously characterized as DEX-sensitive (n = 15), or resistant (n = 10). Real-time PCR analysis of GR 5′UTR mRNA isoforms showed that all HUVECs expressed isoforms 1B, 1C, 1D, 1F, and 1H, and isoforms 1B and 1C were predominantly expressed. DEX-resistant cells expressed higher basal levels of the 5′UTR mRNA isoforms 1C and 1D, but lower levels of the 5′UTR mRNA isoform 1F than DEX-sensitive cells. DEX treatment significantly decreased GRα and GR-1C mRNA isoform expression in DEX-resistant cells only. Reporter luciferase assays indicated that differential GR mRNA isoform expression was not due to differential promoter usage between DEX-sensitive and DEX-resistant cells. Analysis of promoter methylation, however, showed that DEX-sensitive cells have higher methylation levels of promoter 1D and lower methylation levels of promoter 1F than DEX-resistant cells. Treatment with 5-aza-2-deoxycytidine abolished the differential 5′UTR mRNA isoform expression between DEX-sensitive and DEX-resistant cells. Finally, both GRα overexpression and 5-aza-2-deoxycytidine treatment eliminated the differences between sensitivity groups to DEX-mediated downregulation of endothelial nitric oxide synthase (NOS3), and upregulation of plasminogen activator inhibitor 1 (SERPINE1). In sum, human endothelial GR 5′UTR mRNA expression is regulated by promoter methylation with DEX-sensitive and DEX-resistant cells having different GR promoter methylation patterns. PMID:26242202

  17. A Role for Glucocorticoids in Stress-Impaired Reproduction: Beyond the Hypothalamus and Pituitary

    PubMed Central

    Whirledge, Shannon

    2013-01-01

    In addition to the well-characterized role of the sex steroid receptors in regulating fertility and reproduction, reproductive events are also mediated by the hypothalamic-pituitary-adrenal axis in response to an individual's environment. Glucocorticoid secretion in response to stress contributes to the well-characterized suppression of the hypothalamic-pituitary-gonadal axis through central actions in the hypothalamus and pituitary. However, both animal and in vitro studies indicate that other components of the reproductive system are also regulated by glucocorticoids. Furthermore, in the absence of stress, it appears that homeostatic glucocorticoid signaling plays a significant role in reproduction and fertility in all tissues comprising the hypothalamic-pituitary-gonadal axis. Indeed, as central regulators of the immune response, glucocorticoids are uniquely poised to integrate an individual's infectious, inflammatory, stress, nutritional, and metabolic status through glucocorticoid receptor signaling in target tissues. Endocrine signaling between tissues regulating the immune and stress response and those determining reproductive status provides an evolutionary advantage, facilitating the trade-off between reproductive investment and offspring fitness. This review focuses on the actions of glucocorticoids in tissues important for fertility and reproduction, highlighting recent studies that show glucocorticoid signaling plays a significant role throughout the hypothalamic-pituitary-gonadal axis and characterizing these effects as permissive or inhibitory in terms of facilitating reproductive success. PMID:24064362

  18. The Interactome of the Glucocorticoid Receptor and Its Influence on the Actions of Glucocorticoids in Combatting Inflammatory and Infectious Diseases

    PubMed Central

    Petta, Ioanna; Dejager, Lien; Ballegeer, Marlies; Lievens, Sam; Tavernier, Jan; Libert, Claude

    2016-01-01

    SUMMARY 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. PMID:27169854

  19. Glucocorticoid and cytokine crosstalk: Feedback, feedforward, and co-regulatory interactions determine repression or resistance.

    PubMed

    Newton, Robert; Shah, Suharsh; Altonsy, Mohammed O; Gerber, Antony N

    2017-04-28

    Inflammatory signals induce feedback and feedforward systems that provide temporal control. Although glucocorticoids can repress inflammatory gene expression, glucocorticoid receptor recruitment increases expression of negative feedback and feedforward regulators, including the phosphatase, DUSP1, the ubiquitin-modifying enzyme, TNFAIP3, or the mRNA-destabilizing protein, ZFP36. Moreover, glucocorticoid receptor cooperativity with factors, including nuclear factor-κB (NF-κB), may enhance regulator expression to promote repression. Conversely, MAPKs, which are inhibited by glucocorticoids, provide feedforward control to limit expression of the transcription factor IRF1, and the chemokine, CXCL10. We propose that modulation of feedback and feedforward control can determine repression or resistance of inflammatory gene expression toglucocorticoid. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  20. Glucocorticoid sensitivity, disuse, and the regulation of muscle mass

    NASA Technical Reports Server (NTRS)

    Almon, R. R.; Dubois, D. C.

    1983-01-01

    A new noninvasive immobilization procedure to be used on rats has been developed to study immobilization-induced muscle hypersensitivity to normal glucocorticoid concentration, subsequent muscle atrophy, and atrophy recovery. The immobilization procedure involves encasing the hind limb in a light-weight plasticlike cast (10 percent the usual plaster weight), completely resistant to animal gnawing. The effects of right-angle immobilization of the ankle on the slow fiber soleus, and the fast fiber extensor digitorum longus, resemble the effects of weightlessness. The increased concentration of glucocorticoid receptor sites in immobilized and denervated muscle is discussed, along with the chronic loss of muscle mass that occurs in practically all dystrophies. It is concluded that lack of mechanical work in a zero gravity environment is a major cause of glucocorticoid hypersensitivity in the body's musculature.

  1. Differentiation and Glucocorticoid Regulated Apopto-Phagocytic Gene Expression Patterns in Human Macrophages. Role of Mertk in Enhanced Phagocytosis

    PubMed Central

    Zahuczky, Gábor; Kristóf, Endre; Majai, Gyöngyike; Fésüs, László

    2011-01-01

    The daily clearance of physiologically dying cells is performed safely mainly by cells in the mononuclear phagocyte system. They can recognize and engulf dying cells utilizing several cooperative mechanisms. In our study we show that the expression of a broad range of apopto-phagocytic genes is strongly up-regulated during differentiation of human monocytes to macrophages with different donor variability. The glucocorticoid dexamethasone has a profound effect on this process by selectively up-regulating six genes and down-regulating several others. The key role of the up-regulated mer tyrosine kinase (Mertk) in dexamethasone induced enhancement of phagocytosis could be demonstrated in human monocyte derived macrophages by gene silencing as well as blocking antibodies, and also in a monocyte-macrophage like cell line. However, the additional role of other glucocorticoid induced elements must be also considered since the presence of autologous serum during phagocytosis could almost completely compensate for the blocked function of Mertk. PMID:21731712

  2. Gamma-secretase inhibitors reverse glucocorticoid resistance in T-ALL

    PubMed Central

    Real, Pedro J.; Tosello, Valeria; Palomero, Teresa; Castillo, Mireia; Hernando, Eva; de Stanchina, Elisa; Sulis, Maria Luisa; Barnes, Kelly; Sawai, Catherine; Homminga, Irene; Meijerink, Jules; Aifantis, Iannis; Basso, Giuseppe; Cordon-Cardo, Carlos; Ai, Walden; Ferrando, Adolfo

    2009-01-01

    Summary Gamma-secretase inhibitors (GSIs) block the activation of oncogenic NOTCH1 in T-cell acute lymphoblastic leukemia (T-ALL). However, limited antileukemic cytotoxicity and severe gastrointestinal toxicity have restricted the clinical application of these targeted drugs. Here we show that combination therapy with GSIs plus glucocorticoids can improve the antileukemic effects of GSIs and reduce their gut toxicity in vivo. Inhibition of NOTCH1 signaling in glucocorticoid-resistant T-ALL restored glucocorticoid receptor auto-up-regulation and induced apoptotic cell death through induction of BIM expression. GSI treatment resulted in cell cycle arrest and accumulation of goblet cells in the gut mediated by upregulation of Klf4, a negative regulator of cell cycle required for goblet cell differentiation. In contrast, glucocorticoid treatment induced transcriptional upregulation of Ccnd2 and protected mice from developing intestinal goblet cell metaplasia typically induced by inhibition of NOTCH signaling with GSIs. These results support a role for glucocorticoids plus GSIs in the treatment of glucocorticoid-resistant T-ALL. PMID:19098907

  3. Identification of a tumor-promoter cholesterol metabolite in human breast cancers acting through the glucocorticoid receptor

    PubMed Central

    Voisin, Maud; de Medina, Philippe; Mallinger, Arnaud; Dalenc, Florence; Huc-Claustre, Emilie; Leignadier, Julie; Serhan, Nizar; Soules, Régis; Ségala, Grégory; Mougel, Aurélie; Noguer, Emmanuel; Mhamdi, Loubna; Bacquié, Elodie; Iuliano, Luigi; Zerbinati, Chiara; Lacroix-Triki, Magali; Chaltiel, Léonor; Filleron, Thomas; Cavaillès, Vincent; Al Saati, Talal; Rochaix, Philippe; Duprez-Paumier, Raphaelle; Franchet, Camille; Ligat, Laetitia; Lopez, Fréderic; Record, Michel; Poirot, Marc; Silvente-Poirot, Sandrine

    2017-01-01

    Breast cancer (BC) remains the primary cause of death from cancer among women worldwide. Cholesterol-5,6-epoxide (5,6-EC) metabolism is deregulated in BC but the molecular origin of this is unknown. Here, we have identified an oncometabolism downstream of 5,6-EC that promotes BC progression independently of estrogen receptor α expression. We show that cholesterol epoxide hydrolase (ChEH) metabolizes 5,6-EC into cholestane-3β,5α,6β-triol, which is transformed into the oncometabolite 6-oxo-cholestan-3β,5α-diol (OCDO) by 11β-hydroxysteroid-dehydrogenase-type-2 (11βHSD2). 11βHSD2 is known to regulate glucocorticoid metabolism by converting active cortisol into inactive cortisone. ChEH inhibition and 11βHSD2 silencing inhibited OCDO production and tumor growth. Patient BC samples showed significant increased OCDO levels and greater ChEH and 11βHSD2 protein expression compared with normal tissues. The analysis of several human BC mRNA databases indicated that 11βHSD2 and ChEH overexpression correlated with a higher risk of patient death, highlighting that the biosynthetic pathway producing OCDO is of major importance to BC pathology. OCDO stimulates BC cell growth by binding to the glucocorticoid receptor (GR), the nuclear receptor of endogenous cortisol. Interestingly, high GR expression or activation correlates with poor therapeutic response or prognosis in many solid tumors, including BC. Targeting the enzymes involved in cholesterol epoxide and glucocorticoid metabolism or GR may be novel strategies to prevent and treat BC. PMID:29078321

  4. Identification of a tumor-promoter cholesterol metabolite in human breast cancers acting through the glucocorticoid receptor.

    PubMed

    Voisin, Maud; de Medina, Philippe; Mallinger, Arnaud; Dalenc, Florence; Huc-Claustre, Emilie; Leignadier, Julie; Serhan, Nizar; Soules, Régis; Ségala, Grégory; Mougel, Aurélie; Noguer, Emmanuel; Mhamdi, Loubna; Bacquié, Elodie; Iuliano, Luigi; Zerbinati, Chiara; Lacroix-Triki, Magali; Chaltiel, Léonor; Filleron, Thomas; Cavaillès, Vincent; Al Saati, Talal; Rochaix, Philippe; Duprez-Paumier, Raphaelle; Franchet, Camille; Ligat, Laetitia; Lopez, Fréderic; Record, Michel; Poirot, Marc; Silvente-Poirot, Sandrine

    2017-10-31

    Breast cancer (BC) remains the primary cause of death from cancer among women worldwide. Cholesterol-5,6-epoxide (5,6-EC) metabolism is deregulated in BC but the molecular origin of this is unknown. Here, we have identified an oncometabolism downstream of 5,6-EC that promotes BC progression independently of estrogen receptor α expression. We show that cholesterol epoxide hydrolase (ChEH) metabolizes 5,6-EC into cholestane-3β,5α,6β-triol, which is transformed into the oncometabolite 6-oxo-cholestan-3β,5α-diol (OCDO) by 11β-hydroxysteroid-dehydrogenase-type-2 (11βHSD2). 11βHSD2 is known to regulate glucocorticoid metabolism by converting active cortisol into inactive cortisone. ChEH inhibition and 11βHSD2 silencing inhibited OCDO production and tumor growth. Patient BC samples showed significant increased OCDO levels and greater ChEH and 11βHSD2 protein expression compared with normal tissues. The analysis of several human BC mRNA databases indicated that 11βHSD2 and ChEH overexpression correlated with a higher risk of patient death, highlighting that the biosynthetic pathway producing OCDO is of major importance to BC pathology. OCDO stimulates BC cell growth by binding to the glucocorticoid receptor (GR), the nuclear receptor of endogenous cortisol. Interestingly, high GR expression or activation correlates with poor therapeutic response or prognosis in many solid tumors, including BC. Targeting the enzymes involved in cholesterol epoxide and glucocorticoid metabolism or GR may be novel strategies to prevent and treat BC. Published under the PNAS license.

  5. The Microtubule-Associated Protein Doublecortin-Like Regulates the Transport of the Glucocorticoid Receptor in Neuronal Progenitor Cells

    PubMed Central

    Fitzsimons, Carlos P.; Ahmed, Suaad; Wittevrongel, Christiaan F. W.; Schouten, Theo G.; Dijkmans, Thomas F.; Scheenen, Wim J. J. M.; Schaaf, Marcel J. M.; Ronald de Kloet, E.; Vreugdenhil, Erno

    2008-01-01

    In neuronal cells, activated glucocorticoid receptor (GR) translocates to the nucleus guided by the cytoskeleton. However, the detailed mechanisms underlying GR translocation remain unclear. Using gain and loss of function studies, we report here for the first time that the microtubule-associated protein doublecortin-like (DCL) controls GR translocation to the nucleus. DCL overexpression in COS-1 cells, neuroblastoma cells, and rat hippocampus organotypic slice cultures impaired GR translocation and decreased GR-dependent transcriptional activity, measured by a specific reporter gene assay, in COS-1 cells. Moreover, DCL and GR directly interact on microtubule bundles formed by DCL overexpression. A C-terminal truncated DCL with conserved microtubule-bundling activity did not influence GR translocation. In N1E-115 mouse neuroblastoma cells and neuronal progenitor cells in rat hippocampus organotypic slice cultures, laser-scanning confocal microscopy showed colabeling of endogenously expressed DCL and GR. In these systems, RNA-interference-mediated DCL knockdown hampered GR translocation. Thus, we conclude that DCL expression is tightly regulated to adequately control GR transport. Because DCL is primarily expressed in neuronal progenitor cells, our results introduce this microtubule-associated protein as a new modulator of GR signaling in this cell type and suggest the existence of cell-specific mechanisms regulating GR translocation to the nucleus. PMID:17975023

  6. Carbachol does not down-regulate substance P receptors in pancreatic acini.

    PubMed

    Patto, R J; Vinayek, R; Jensen, R T; Gardner, J D

    1992-01-01

    In a previous study, we found that first incubating guinea pig pancreatic acini with carbachol caused desensitization of the enzyme secretory response to cholecystokinin-octapeptide (CCK-8), bombesin, and carbachol but not that to substance P. This carbachol-induced desensitization could be accounted for by carbachol-induced down-regulation of receptors for CCK-8, bombesin, and carbachol. Although carbachol did not desensitize the enzyme secretory response to substance P, an effect of carbachol on substance P receptors was not examined. In the present study, in dispersed acini from guinea pig pancreas, substance P caused a twofold increase in amylase secretion. Stimulation was half-maximal at 0.7 nM and was maximal at 10 nM. Analysis of the ability of substance P to inhibit binding of 125I-substance P to substance P receptors indicated that acini possess a single class of receptors for substance P (Kd = 0.8 +/- 0.1 nM; Bmax = 1,037 +/- 145 fmol/mg of DNA). There was a close correlation between the relative potency with which substance P stimulated amylase secretion (0.7 nM) and the potency for inhibiting binding of 125I-substance P (Kd = 0.8 nM). First incubating pancreatic acini with carbachol did not alter either substance P-stimulated enzyme secretion or binding of 125I-substance P to substance P receptors, whereas in the same experiments, carbachol reduced binding of 125I-CCK-8 to cholecystokinin receptors by 50% and decreased in CCK-8-stimulated enzyme secretion by 50%.(ABSTRACT TRUNCATED AT 250 WORDS)

  7. Doubling the Size of the Glucocorticoid Receptor Ligand Binding Pocket by Deacylcortivazol

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Suino-Powell, Kelly; Xu, Yong; Zhang, Chenghai

    A common feature of nuclear receptor ligand binding domains (LBD) is a helical sandwich fold that nests a ligand binding pocket within the bottom half of the domain. Here we report that the ligand pocket of glucocorticoid receptor (GR) can be continuously extended into the top half of the LBD by binding to deacylcortivazol (DAC), an extremely potent glucocorticoid. It has been puzzling for decades why DAC, which contains a phenylpyrazole replacement at the conserved 3-ketone of steroid hormones that are normally required for activation of their cognate receptors, is a potent GR activator. The crystal structure of the GRmore » LBD bound to DAC and the fourth LXXLL motif of steroid receptor coactivator 1 reveals that the GR ligand binding pocket is expanded to a size of 1,070 {angstrom}{sup 3}, effectively doubling the size of the GR dexamethasone-binding pocket of 540 {angstrom}{sup 3} and yet leaving the structure of the coactivator binding site intact. DAC occupies only {approx}50% of the space of the pocket but makes intricate interactions with the receptor around the phenylpyrazole group that accounts for the high-affinity binding of DAC. The dramatic expansion of the DAC-binding pocket thus highlights the conformational adaptability of GR to ligand binding. The new structure also allows docking of various nonsteroidal ligands that cannot be fitted into the previous structures, thus providing a new rational template for drug discovery of steroidal and nonsteroidal glucocorticoids that can be specifically designed to reach the unoccupied space of the expanded pocket.« less

  8. Effect of the glucocorticoid receptor antagonist Org 34850 on basal and stress-induced corticosterone secretion.

    PubMed

    Spiga, F; Harrison, L R; Wood, S A; Atkinson, H C; MacSweeney, C P; Thomson, F; Craighead, M; Grassie, M; Lightman, S L

    2007-11-01

    The activity of the hypothalamic-pituitary-adrenal (HPA) axis is characterised both by an ultradian pulsatile pattern of glucocorticoid secretion and an endogenous diurnal rhythm. Glucocorticoid feedback plays a major role in regulating HPA axis activity and this mechanism occurs via two different receptors: mineralocorticoid (MR) and glucocorticoid receptors (GR). In the present study, the effects of both acute and subchronic treatment with the GR antagonist Org 34850 on basal and stress-induced HPA axis activity in male rats were evaluated. To investigate the effect of Org 34850 on basal diurnal corticosterone rhythm over the 24-h cycle, an automated blood sampling system collected samples every 10 min. Acute injection of Org 34850 (10 mg/kg, s.c.) did not affect basal or stress-induced corticosterone secretion, but was able to antagonise the inhibitory effect of the glucocorticoid agonist methylprednisolone on stress-induced corticosterone secretion. However, 5 days of treatment with Org 34850 (10 mg/kg, s.c., two times a day), compared to rats treated with vehicle (5% mulgofen in 0.9% saline, 1 ml/kg, s.c.), increased corticosterone secretion over the 24-h cycle and resulted in changes in the pulsatile pattern of hormone release, but had no significant effect on adrenocorticotrophic hormone secretion or on stress-induced corticosterone secretion. Subchronic treatment with Org 34850 did not alter GR mRNA expression in the hippocampus, paraventricular nucleus of the hypothalamus or anterior-pituitary, or MR mRNA expression in the hippocampus. Our data suggest that a prolonged blockade of GRs is required to increase basal HPA axis activity. The changes observed here with ORG 34850 are consistent with inhibition of GR-mediated negative feedback of the HPA axis. In light of the evidence showing an involvement of dysfunctional HPA axis in the pathophysiology of depression, Org 34850 could be a potential treatment for mood disorders.

  9. The glucocorticoid receptor regulates the binding of C/EPBbeta on the alpha-1-acid glycoprotein promoter in vivo.

    PubMed

    Savoldi, G; Fenaroli, A; Ferrari, F; Rigaud, G; Albertini, A; Di Lorenzo, D

    1997-12-01

    A complex interaction between the Glucocorticoid Receptor (GR), C/EBPbeta, and other transcription factors activate the Alpha-1 Acid Glycoprotein (AGP) promoter in HTC(JZ-1) rat hepatoma culture cells. This effect is mediated by the so-called Steroid Responsive Unit (SRU) of the AGP promoter that contains several binding sites for C/EBP transcription factors, some of which overlap with the Glucocorticoid Responsive Element (GRE). Our in vivo footprinting experiments revealed that the GRE- and the C/EBP-binding sites were already occupied glucocorticoid dependently in HTC(JZ-1) cells 10 min after dexamethasone administration (10(-6) M). Furthermore, local changes in the chromatine structure shown by the appearance of DNAse I hypersensitive sites (HS sites) also took place. These changes were probably dependent on a tissue-specific organization of the chromatine at the SRU because they were not detectable in a different glucocorticoid-responsive cell line (PC12) that did not express AGP. Here, we have also shown that withdrawal of dexamethasone or addition of the anti-glucocorticoid RU486 were able to revert the pattern induced by dexamethasone in vivo. The disappearance of the protected region and the hypersensitive sites, typical of the hormone activated promoter, confirmed the necessity of the GR to be bound by the agonist and the inability of the GR-antagonist complex to bind the DNA. By functional assays, we showed that the occupancy of the SRU by these transcriptional proteins in vivo correlated with the activation of the AGP gene transcription. With these results, we have shown that one of the functions of the GR to activate transcription of the AGP gene is to recruit C/EBPbeta and to maintain it bound at its target DNA sequences (SRU). This process was not accomplished by RU486.

  10. A novel point mutation of the human glucocorticoid receptor gene causes primary generalized glucocorticoid resistance through impaired interaction with the LXXLL motif of the p160 coactivators: dissociation of the transactivating and transreppressive activities.

    PubMed

    Nicolaides, Nicolas C; Roberts, Michael L; Kino, Tomoshige; Braatvedt, Geoffrey; Hurt, Darrell E; Katsantoni, Eleni; Sertedaki, Amalia; Chrousos, George P; Charmandari, Evangelia

    2014-05-01

    Primary generalized glucocorticoid resistance is a rare genetic disorder characterized by generalized, partial, target-tissue insensitivity to glucocorticoids. The molecular basis of the condition has been ascribed to inactivating mutations in the human glucocorticoid receptor (hGR) gene. The objective of the study was to present three new cases caused by a novel mutation in the hGR gene and to delineate the molecular mechanisms through which the mutant receptor impairs glucocorticoid signal transduction. The index case (father) and his two daughters presented with increased urinary free cortisol excretion and resistance of the hypothalamic-pituitary-adrenal axis to dexamethasone suppression in the absence of clinical manifestations suggestive of Cushing syndrome. All subjects harbored a novel, heterozygous, point mutation (T→G) at nucleotide position 1724 of the hGR gene, which resulted in substitution of valine by glycine at amino acid 575 of the receptor. Compared with the wild-type receptor, the hGRαV575G demonstrated a significant (33%) reduction in its ability to transactivate the mouse mammary tumor virus promoter in response to dexamethasone, a 50% decrease in its affinity for the ligand, and a 2.5-fold delay in nuclear translocation. Although it did not exert a dominant negative effect on the wild-type receptor and preserved its ability to bind to DNA, hGRαV575G displayed significantly enhanced (∼80%) ability to transrepress the nuclear factor-κΒ signaling pathway. Finally, the mutant receptor hGRαV575G demonstrated impaired interaction with the LXXLL motif of the glucocorticoid receptor-interacting protein 1 coactivator in vitro and in computer-based structural simulation via its defective activation function-2 (AF-2) domain. The natural mutant receptor hGRαV575G causes primary generalized glucocorticoid resistance by affecting multiple steps in the glucocorticoid signaling cascade, including the affinity for the ligand, the time required for

  11. Role of the chromatin landscape and sequence in determining cell type-specific genomic glucocorticoid receptor binding and gene regulation

    PubMed Central

    Huska, Matthew R.; Jurk, Marcel; Schöpflin, Robert; Starick, Stephan R.; Schwahn, Kevin; Cooper, Samantha B.; Yamamoto, Keith R.; Thomas-Chollier, Morgane; Vingron, Martin

    2017-01-01

    Abstract The genomic loci bound by the glucocorticoid receptor (GR), a hormone-activated transcription factor, show little overlap between cell types. To study the role of chromatin and sequence in specifying where GR binds, we used Bayesian modeling within the universe of accessible chromatin. Taken together, our results uncovered that although GR preferentially binds accessible chromatin, its binding is biased against accessible chromatin located at promoter regions. This bias can only be explained partially by the presence of fewer GR recognition sequences, arguing for the existence of additional mechanisms that interfere with GR binding at promoters. Therefore, we tested the role of H3K9ac, the chromatin feature with the strongest negative association with GR binding, but found that this correlation does not reflect a causative link. Finally, we find a higher percentage of promoter–proximal GR binding for genes regulated by GR across cell types than for cell type-specific target genes. Given that GR almost exclusively binds accessible chromatin, we propose that cell type-specific regulation by GR preferentially occurs via distal enhancers, whose chromatin accessibility is typically cell type-specific, whereas ubiquitous target gene regulation is more likely to result from binding to promoter regions, which are often accessible regardless of cell type examined. PMID:27903902

  12. Endothelial nuclear lamina is not required for glucocorticoid receptor nuclear import but does affect receptor-mediated transcription activation.

    PubMed

    Nayebosadri, Arman; Ji, Julie Y

    2013-08-01

    The lamina serves to maintain the nuclear structure and stiffness while acting as a scaffold for heterochromatin and many transcriptional proteins. Its role in endothelial mechanotransduction, specifically how nuclear mechanics impact gene regulation under shear stress, is not fully understood. In this study, we successfully silenced lamin A/C in bovine aortic endothelial cells to determine its role in both glucocorticoid receptor (GR) nuclear translocation and glucocorticoid response element (GRE) transcriptional activation in response to dexamethasone and shear stress. Nuclear translocation of GR, an anti-inflammatory nuclear receptor, in response to dexamethasone or shear stress (5, 10, and 25 dyn/cm(2)) was observed via time-lapse cell imaging and quantified using a Bayesian image analysis algorithm. Transcriptional activity of the GRE promoter was assessed using a dual-luciferase reporter plasmid. We found no dependence on nuclear lamina for GR translocation from the cytoplasm into the nucleus. However, the absence of lamin A/C led to significantly increased expression of luciferase under dexamethasone and shear stress induction as well as changes in histone protein function. PCR results for NF-κB inhibitor alpha (NF-κBIA) and dual specificity phosphatase 1 (DUSP1) genes further supported our luciferase data with increased expression in the absence of lamin. Our results suggest that absence of lamin A/C does not hinder passage of GR into the nucleus, but nuclear lamina is important to properly regulate GRE transcription. Nuclear lamina, rather than histone deacetylase (HDAC), is a more significant mediator of shear stress-induced transcriptional activity, while dexamethasone-initiated transcription is more HDAC dependent. Our findings provide more insights into the molecular pathways involved in nuclear mechanotransduction.

  13. Endothelial nuclear lamina is not required for glucocorticoid receptor nuclear import but does affect receptor-mediated transcription activation

    PubMed Central

    Nayebosadri, Arman

    2013-01-01

    The lamina serves to maintain the nuclear structure and stiffness while acting as a scaffold for heterochromatin and many transcriptional proteins. Its role in endothelial mechanotransduction, specifically how nuclear mechanics impact gene regulation under shear stress, is not fully understood. In this study, we successfully silenced lamin A/C in bovine aortic endothelial cells to determine its role in both glucocorticoid receptor (GR) nuclear translocation and glucocorticoid response element (GRE) transcriptional activation in response to dexamethasone and shear stress. Nuclear translocation of GR, an anti-inflammatory nuclear receptor, in response to dexamethasone or shear stress (5, 10, and 25 dyn/cm2) was observed via time-lapse cell imaging and quantified using a Bayesian image analysis algorithm. Transcriptional activity of the GRE promoter was assessed using a dual-luciferase reporter plasmid. We found no dependence on nuclear lamina for GR translocation from the cytoplasm into the nucleus. However, the absence of lamin A/C led to significantly increased expression of luciferase under dexamethasone and shear stress induction as well as changes in histone protein function. PCR results for NF-κB inhibitor alpha (NF-κBIA) and dual specificity phosphatase 1 (DUSP1) genes further supported our luciferase data with increased expression in the absence of lamin. Our results suggest that absence of lamin A/C does not hinder passage of GR into the nucleus, but nuclear lamina is important to properly regulate GRE transcription. Nuclear lamina, rather than histone deacetylase (HDAC), is a more significant mediator of shear stress-induced transcriptional activity, while dexamethasone-initiated transcription is more HDAC dependent. Our findings provide more insights into the molecular pathways involved in nuclear mechanotransduction. PMID:23703529

  14. Nuclear localisation of calreticulin in vivo is enhanced by its interaction with glucocorticoid receptors.

    PubMed

    Roderick, H L; Campbell, A K; Llewellyn, D H

    1997-03-24

    The multi-functional protein calreticulin (CRT) is normally found within the lumen of the endoplasmic reticulum (ER). However, some of its proposed functions require it to be located within the nucleus, where its presence is contentious. We have investigated this in live COS7, HeLa and LM(TK-) cells using green fluorescent protein (GFP)-fusion proteins. GFP-CRT, and GFP, with an ER signal peptide and a KDEL sequence (ER-GFP), were localised to the ER. In addition, GFP-CRT was located in the nucleus of all the cell types at low levels. The higher levels of nuclear fluorescence in LM(TK-) and HeLa cells suggested that glucocorticoid receptors might enhance nuclear localisation of calreticulin. Dexamethasone treatment of LM(TK-) cells doubled the amount of nuclear GFP-CRT, but did not affect the localisation of a GFP-CRT fusion in which the glucocorticoid receptor-binding N-domain of calreticulin had been deleted. Thus, despite ER targeting and retention signals, calreticulin is also located within the nucleus where its presence increases due to its interaction with glucocorticoid receptors.

  15. Regulation of Steroid Hormone Receptor Function By the 52-kDa FK506-Binding Protein (FKBP52)

    PubMed Central

    Sivils, Jeffrey C.; Storer, Cheryl L.; Galigniana, Mario D.; Cox, Marc B.

    2011-01-01

    The large FK506-binding protein FKBP52 has been characterized as an important positive regulator of androgen, glucocorticoid and progesterone receptor signaling pathways. FKBP52 associates with receptor-Hsp90 complexes and is proposed to have roles in both receptor hormone binding and receptor subcellular localization. Data from biochemical and cellular studies has been corroborated in whole animal models as fkbp52-deficient male and female mice display characteristics of androgen, glucocorticoid and/or progesterone insensitivity. FKBP52 receptor specificity and the specific phenotypes displayed by the fkbp52-deficient mice have firmly established FKBP52 as a promising target for the treatment of a variety of hormone-dependent diseases. Recent studies demonstrated that the FKBP52 FK1 domain and the proline-rich loop within this domain are functionally important for FKBP52 regulation of receptor function. Based on these data, efforts are currently underway to target the FKBP52 FK1 domain and the proline-rich loop with small molecule inhibitors. PMID:21511531

  16. Activation of mineralocorticoid receptors by exogenous glucocorticoids and the development of cardiovascular inflammatory responses in adrenalectomized rats.

    PubMed

    Young, Morag J; Morgan, James; Brolin, Kim; Fuller, Peter J; Funder, John W

    2010-06-01

    Activation of the mineralocorticoid receptor (MR) in the context of a high salt intake produces cardiovascular inflammation plus cardiac fibrosis and failure. Inactivation of vascular 11beta-hydroxysteroid dehydrogenase type 2 activity in intact animals by carbenoxolone (CBX) produces a similar pathology, presumably reflecting coronary vascular MR activation by endogenous glucocorticoids. To test this hypothesis, we have used adrenalectomized rats, without endogenous corticosteroids, and examined the consequences of corticosterone (CORT) replacement on a series of cardiovascular disease parameters. Uninephrectomized adrenalectomized Sprague Dawley rats given 1% NaCl/0.3% KCl to drink were treated for 8 d as follows: control; 20 mg deoxycorticosterone (DOC); 2 mg/d CORT; 2.5 mg/d CBX; CORT plus CBX (CORT/CBX); and CORT/CBX plus 100 mg/kg.d eplerenone. Markers of cardiac oxidative stress (p22(phox) and NOX4 mRNA) were up-regulated in the DOC and CORT/CBX groups; in contrast, inflammatory cell infiltration was increased and endothelial nitric oxide synthase down-regulated by CORT as well as by DOC and CORT/CBX. In the kidney, connective tissue growth factor mRNA levels were increased by DOC and CORT/CBX; in contrast, DOC had no effect on mRNA levels for channel inducing factor or endothelin 3, which were elevated only by CORT/CBX. All changes noted were reversed by eplerenone. Rats given 10-fold lower CORT (0.2 mg/d) with or without CBX showed no change in any parameter. These results suggest that there exist distinct but overlapping ligand-specific MR-mediated tissue responses to a classic mineralocorticoid (DOC) and to the glucocorticoid CORT, in the presence and absence of CBX to block vascular 11beta-hydroxysteroid dehydrogenase type 2.

  17. Mechanisms for the Evolution of a Derived Function in the Ancestral Glucocorticoid Receptor

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Carroll, Sean Michael; Ortlund, Eric A; Thornton, Joseph W.

    2012-03-16

    Understanding the genetic, structural, and biophysical mechanisms that caused protein functions to evolve is a central goal of molecular evolutionary studies. Ancestral sequence reconstruction (ASR) offers an experimental approach to these questions. Here we use ASR to shed light on the earliest functions and evolution of the glucocorticoid receptor (GR), a steroid-activated transcription factor that plays a key role in the regulation of vertebrate physiology. Prior work showed that GR and its paralog, the mineralocorticoid receptor (MR), duplicated from a common ancestor roughly 450 million years ago; the ancestral functions were largely conserved in the MR lineage, but the functionsmore » of GRs - reduced sensitivity to all hormones and increased selectivity for glucocorticoids - are derived. Although the mechanisms for the evolution of glucocorticoid specificity have been identified, how reduced sensitivity evolved has not yet been studied. Here we report on the reconstruction of the deepest ancestor in the GR lineage (AncGR1) and demonstrate that GR's reduced sensitivity evolved before the acquisition of restricted hormone specificity, shortly after the GR-MR split. Using site-directed mutagenesis, X-ray crystallography, and computational analyses of protein stability to recapitulate and determine the effects of historical mutations, we show that AncGR1's reduced ligand sensitivity evolved primarily due to three key substitutions. Two large-effect mutations weakened hydrogen bonds and van der Waals interactions within the ancestral protein, reducing its stability. The degenerative effect of these two mutations is extremely strong, but a third permissive substitution, which has no apparent effect on function in the ancestral background and is likely to have occurred first, buffered the effects of the destabilizing mutations. Taken together, our results highlight the potentially creative role of substitutions that partially degrade protein structure and

  18. The obesity-associated transcription factor ETV5 modulates circulating glucocorticoids

    PubMed Central

    Gutierrez-Aguilar, Ruth; Thompson, Abigail; Marchand, Nathalie; Dumont, Patrick; Woods, Stephen C.; de Launoit, Yvan; Seeley, Randy J.; Ulrich-Lai, Yvonne M.

    2015-01-01

    The transcription factor E-twenty-six version 5 (ETV5) has been linked with obesity in genome-wide association studies. Moreover, ETV5-deficient mice (knockout; KO) have reduced body weight, lower fat mass, and are resistant to diet-induced obesity, directly linking ETV5 to the regulation of energy balance and metabolism. ETV5 is expressed in hypothalamic brain regions that regulate both metabolism and HPA axis activity, suggesting that ETV5 may also modulate HPA axis function. In order to test this possibility, plasma corticosterone levels were measured in ETV5 KO and wildtype (WT) mice before (pre-stress) and after (post-stress) a mild stressor (intraperitoneal injection). ETV5 deficiency increased both pre- and post-stress plasma corticosterone, suggesting that loss of ETV5 elevated glucocorticoid tone. Consistent with this idea, ETV5 KO mice have reduced thymus weight, suggestive of increased glucocorticoid-induced thymic involution. ETV5 deficiency also decreased the mRNA expression of glucocorticoid receptor (GR), mineralocorticoid receptor (MR), and vasopressin receptor 1A in the hypothalamus, without altering vasopressin, corticotropin-releasing hormone, or oxytocin mRNA expression. In order to test whether reduced MR and GR expression affected glucocorticoid negative feedback, a dexamethasone suppression test was performed. Dexamethasone reduced plasma corticosterone in both ETV5 KO and WT mice, suggesting that glucocorticoid negative feedback was unaltered by ETV5 deficiency. In summary, these data suggest that the obesity-associated transcription factor ETV5 normally acts to diminish circulating glucocorticoids. This might occur directly via ETV5 actions on HPA-regulatory brain circuitry, and/or indirectly via ETV5-induced alterations in metabolic factors that then influence the HPA axis. PMID:25813907

  19. Yin Yang 1 Promotes Hepatic Gluconeogenesis Through Upregulation of Glucocorticoid Receptor

    PubMed Central

    Lu, Yan; Xiong, Xuelian; Wang, Xiaolin; Zhang, Zhijian; Li, Jin; Shi, Guojun; Yang, Jian; Zhang, Huijie; Ning, Guang; Li, Xiaoying

    2013-01-01

    Gluconeogenesis is critical in maintaining blood glucose levels in a normal range during fasting. In this study, we investigated the role of Yin Yang 1 (YY1), a key transcription factor involved in cell proliferation and differentiation, in the regulation of hepatic gluconeogenesis. Our data showed that hepatic YY1 expression levels were induced in mice during fasting conditions and in a state of insulin resistance. Overexpression of YY1 in livers augmented gluconeogenesis, raising fasting blood glucose levels in C57BL/6 mice, whereas liver-specific ablation of YY1 using adenoviral shRNA ameliorated hyperglycemia in wild-type and diabetic db/db mice. At the molecular level, we further demonstrated that the major mechanism of YY1 in the regulation of hepatic glucose production is to modulate the expression of glucocorticoid receptor. Therefore, our study uncovered for the first time that YY1 participates in the regulation of hepatic gluconeogenesis, which implies that YY1 might serve as a potential therapeutic target for hyperglycemia in diabetes. PMID:23193188

  20. Effect of cAMP signaling on expression of glucocorticoid receptor, Bim and Bad in glucocorticoid-sensitive and resistant leukemic and multiple myeloma cells.

    PubMed

    Dong, Hongli; Carlton, Michael E; Lerner, Adam; Epstein, Paul M

    2015-01-01

    Stimulation of cAMP signaling induces apoptosis in glucocorticoid-sensitive and resistant CEM leukemic and MM.1 multiple myeloma cell lines, and this effect is enhanced by dexamethasone in both glucocorticoid-sensitive cell types and in glucocorticoid-resistant CEM cells. Expression of the mRNA for the glucocorticoid receptor alpha (GR) promoters 1A3, 1B and 1C, expression of mRNA and protein for GR, and the BH3-only proapoptotic proteins, Bim and Bad, and the phosphorylation state of Bad were examined following stimulation of the cAMP and glucocorticoid signaling pathways. Expression levels of GR promoters were increased by cAMP and glucocorticoid signaling, but GR protein expression was little changed in CEM and decreased in MM.1 cells. Stimulation of these two signaling pathways induced Bim in CEM cells, induced Bad in MM.1 cells, and activated Bad, as indicated by its dephosphorylation on ser112, in both cell types. This study shows that leukemic and multiple myeloma cells, including those resistant to glucocorticoids, can be induced to undergo apoptosis by stimulating the cAMP signaling pathway, with enhancement by glucocorticoids, and the mechanism by which this occurs may be related to changes in Bim and Bad expression, and in all cases, to activation of Bad.

  1. MicroRNA-122 Down-Regulation Is Involved in Phenobarbital-Mediated Activation of the Constitutive Androstane Receptor

    PubMed Central

    Shizu, Ryota; Shindo, Sawako; Yoshida, Takemi; Numazawa, Satoshi

    2012-01-01

    Constitutive androstane receptor (CAR) is a nuclear receptor that regulates the transcription of target genes, including CYP2B and 3A. Phenobarbital activates CAR, at least in part, in an AMP-activated protein kinase (AMPK)-dependent manner. However, the precise mechanisms underlying phenobarbital activation of AMPK are still unclear. In the present study, it was demonstrated that phenobarbital administration to mice decreases hepatic miR-122, a liver-enriched microRNA involved in both hepatic differentiation and function. The time-course change in the phenobarbital-mediated down-regulation of miR-122 was inversely correlated with AMPK activation. Phenobarbital decreased primary miR-122 to approximately 25% of the basal level as early as 1 h and suppressed transactivity of mir-122 promoter in HuH-7 cells, suggesting that the down-regulation occurred at the transcriptional level. AMPK activation by metformin or 5-aminoimidazole-4-carboxamide 1-β-D-ribonucleoside had no evident effect on miR-122 levels. An inhibitory RNA specific for miR-122 increased activated AMPK and CAR-mediated trancactivation of the phenobarbital-responsive enhancer module in HepG2 cells. Conversely, the reporter activity induced by the ectopic CAR was almost completely suppressed by co-transfection with the miR-122 mimic RNA. GFP-tagged CAR was expressed in the cytoplasm in addition to the nucleus in the majority of HuH-7 cells in which miR-122 was highly expressed. Co-transfection of the mimic or the inhibitor RNA for miR-122 further increased or decreased, respectively, the number of cells that expressed GFP-CAR in the cytoplasm. Taken together, these results suggest that phenobarbital-mediated down-regulation of miR-122 is an early and important event in the AMPK-dependent CAR activation and transactivation of its target genes. PMID:22815988

  2. Glucocorticoid receptor beta increases migration of human bladder cancer cells.

    PubMed

    McBeth, Lucien; Nwaneri, Assumpta C; Grabnar, Maria; Demeter, Jonathan; Nestor-Kalinoski, Andrea; Hinds, Terry D

    2016-05-10

    Bladder cancer is observed worldwide having been associated with a host of environmental and lifestyle risk factors. Recent investigations on anti-inflammatory glucocorticoid signaling point to a pathway that may impact bladder cancer. Here we show an inverse effect on the glucocorticoid receptor (GR) isoform signaling that may lead to bladder cancer. We found similar GRα expression levels in the transitional uroepithelial cancer cell lines T24 and UMUC-3. However, the T24 cells showed a significant (p < 0.05) increased expression of GRβ compared to UMUC-3, which also correlated with higher migration rates. Knockdown of GRβ in the T24 cells resulted in a decreased migration rate. Mutational analysis of the 3' untranslated region (UTR) of human GRβ revealed that miR144 might positively regulate expression. Indeed, overexpression of miR144 increased GRβ by 3.8 fold. In addition, miR144 and GRβ were upregulated during migration. We used a peptide nucleic acid conjugated to a cell penetrating-peptide (Sweet-P) to block the binding site for miR144 in the 3'UTR of GRβ. Sweet-P effectively prevented miR144 actions and decreased GRβ expression, as well as the migration of the T24 human bladder cancer cells. Therefore, GRβ may have a significant role in bladder cancer, and possibly serve as a therapeutic target for the disease.

  3. Mineralocorticoid receptor function in bone metabolism and its role in glucocorticoid-induced osteopenia.

    PubMed

    Fumoto, Toshio; Ishii, Kiyo-Aki; Ito, Masako; Berger, Stefan; Schütz, Günther; Ikeda, Kyoji

    2014-05-09

    Although the mineralocorticoid receptor (MR) is expressed in osteoblasts and osteocytes and frequently co-localizes with the glucocorticoid receptors (GR), its pathophysiological functions in bone remain elusive. We report here that pharmacologic inhibition of MR function with eplerenone resulted in increased bone mass, with stimulation of bone formation and suppression of resorption, while specific genetic deletion of MR in osteoblast lineage cells had no effect. Further, treatment with eplerenone as well as specific deletion of MR in osteocytes ameliorated the cortical bone thinning caused by slow-release prednisolone pellets. Thus, MR may be involved in the deleterious effects of glucocorticoid excess on cortical bone. Copyright © 2014 Elsevier Inc. All rights reserved.

  4. Endogenous glucocorticoids regulate an inducible cyclooxygenase enzyme.

    PubMed Central

    Masferrer, J L; Seibert, K; Zweifel, B; Needleman, P

    1992-01-01

    The effect of endogenous glucocorticoids on the expression of the cyclooxygenase enzyme was studied by contrasting cyclooxygenase expression and prostanoid synthesis in adrenalectomized and sham-adrenalectomized mice with or without the concurrent administration of endotoxin. Peritoneal macrophages obtained from adrenalectomized mice showed a 2- to 3-fold induction in cyclooxygenase synthesis and activity when compared to sham controls. Intravenous injection of a sublethal dose of endotoxin (5 micrograms/kg) further stimulated cyclooxygenase synthesis, resulting in a 4-fold increase in prostaglandin production. Similar cyclooxygenase induction can be achieved in macrophages obtained from normal mice but only after high doses of endotoxin (2.5 mg/kg) that are 100% lethal to adrenalectomized mice. Restoration of glucocorticoids in adrenalectomized animals with dexamethasone completely inhibited the elevated cyclooxygenase and protected these animals from endotoxin-induced death. In contrast, no signs of cyclooxygenase induction were observed in the kidneys of the adrenalectomized mice, even when treated with endotoxin. Dexamethasone did not affect the constitutive cyclooxygenase activity and prostaglandin production present in normal and adrenalectomized kidneys. These data indicate the existence of a constitutive cyclooxygenase that is normally present in most cells and tissues and is unaffected by steroids and of an inducible cyclooxygenase that is expressed only in the context of inflammation by proinflammatory cells, like macrophages, and that is under glucocorticoid regulation. Under normal physiological conditions glucocorticoids maintain tonic inhibition of inducible cyclooxygenase expression. Depletion of glucocorticoids or the presence of an inflammatory stimulus such as endotoxin causes rapid induction of this enzyme, resulting in an exacerbated inflammatory response that is often lethal. Images PMID:1570314

  5. Social Regulation of Leukocyte Homeostasis: The Role of Glucocorticoid Sensitivity

    PubMed Central

    Cole, Steve W.

    2010-01-01

    Recent small-scale genomics analyses suggest that physiologic regulation of pro-inflammatory gene expression by endogenous glucocorticoids may be compromised in individuals who experience chronic social isolation. This could potentially contribute to the elevated prevalence of inflammation-related disease previously observed in social isolates. The present study assessed the relationship between leukocyte distributional sensitivity to glucocorticoid regulation and subjective social isolation in a large population-based sample of older adults. Initial analyses confirmed that circulating neutrophil percentages were elevated, and circulating lymphocyte and monocyte percentages were suppressed, in direct proportion to circulating cortisol levels. However, leukocyte distributional sensitivity to endogenous glucocorticoids was abrogated in individuals reporting either occasional or frequent experiences of subjective social isolation. This finding held in both nonparametric univariate analyses and in multivariate linear models controlling for a variety of biological, social, behavioral, and psychological confounders. The present results suggest that social factors may alter immune cell sensitivity to physiologic regulation by the hypothalamic-pituitary-adrenal axis in ways that could ultimately contribute to the increased physical health risks associated with social isolation. PMID:18394861

  6. Endocrine-Disrupting Effects of Pesticides through Interference with Human Glucocorticoid Receptor.

    PubMed

    Zhang, Jianyun; Zhang, Jing; Liu, Rui; Gan, Jay; Liu, Jing; Liu, Weiping

    2016-01-05

    Many pesticides have been identified as endocrine-disrupting chemicals (EDCs) due to their ability to bind sex-steroid hormone receptors. However, little attention has been paid to the ability of pesticides to interfere with other steroid hormone receptors such as glucocorticoid receptor (GR) that plays a critical role in metabolic, endocrine, immune, and nervous systems. In this study, the glucocorticoidic and antiglucocorticoidic effects of 34 pesticides on human GR were investigated using luciferase reporter gene assay. Surprisingly, none of the test chemicals showed GR agonistic activity, but 12 chemicals exhibited apparent antagonistic effects. Bifenthrin, λ-cyhalothrin, cypermethrin, resmethrin, o,p'-DDT, p,p'-DDT, methoxychlor, ethiofencarb, and tolylfluanid showed remarkable GR antagonistic properties with RIC20 values lower than 10(-6) M. The disruption of glucocorticoid-responsive genes in H4IIE and J774A.1 cells was further evaluated on these 12 GR antagonists. In H4IIEcells, four organochlorine insecticides, bifenthrin, and 3-PBA decreased cortisol-induced PEPCK gene expression, while o,p'-DDT and methoxychlor inhibited cortisol-stimulated Arg and TAT gene expression. Cypermethrin and tolyfluanid attenuated cortisol-induced TAT expression. In J774A.1 cells, λ-cyhalothrin, resmethrin, 3-PBA, o,p'-DDT, p,p'-DDT, p,p'-DDE, methoxychlor- and tolylfluanid-reduced cortisol-stimulated GILZ expression. Furthermore, molecular docking simulation indicated that different interactions may stabilize the binding between molecules and GR. Our findings suggest that comprehensive screening and evaluation of GR antagonists and agonists should be considered to better understand the health and ecological risks of man-made chemicals such as pesticides.

  7. Structural Analysis on the Pathologic Mutant Glucocorticoid Receptor Ligand-Binding Domains.

    PubMed

    Hurt, Darrell E; Suzuki, Shigeru; Mayama, Takafumi; Charmandari, Evangelia; Kino, Tomoshige

    2016-02-01

    Glucocorticoid receptor (GR) gene mutations may cause familial or sporadic generalized glucocorticoid resistance syndrome. Most of the missense forms distribute in the ligand-binding domain and impair its ligand-binding activity and formation of the activation function (AF)-2 that binds LXXLL motif-containing coactivators. We performed molecular dynamics simulations to ligand-binding domain of pathologic GR mutants to reveal their structural defects. Several calculated parameters including interaction energy for dexamethasone or the LXXLL peptide indicate that destruction of ligand-binding pocket (LBP) is a primary character. Their LBP defects are driven primarily by loss/reduction of the electrostatic interaction formed by R611 and T739 of the receptor to dexamethasone and a subsequent conformational mismatch, which deacylcortivazol resolves with its large phenylpyrazole moiety and efficiently stimulates transcriptional activity of the mutant receptors with LBP defect. Reduced affinity of the LXXLL peptide to AF-2 is caused mainly by disruption of the electrostatic bonds to the noncore leucine residues of this peptide that determine the peptide's specificity to GR, as well as by reduced noncovalent interaction against core leucines and subsequent exposure of the AF-2 surface to solvent. The results reveal molecular defects of pathologic mutant receptors and provide important insights to the actions of wild-type GR.

  8. Kinetic deuterium isotope effects in glucocorticoid receptor activation

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Aranyi, P.

    1984-01-01

    Activation and deactivation of the chick thymus glucocorticoid receptor protein was studied in ordinary and heavy water by DNA-cellulose binding of the tritiated triamcinolone acetonide-receptor complex. Activation was significantly slower in heavy water if it was promoted by incubation at elevated temperature in buffers of low ionic strength. In the presence of 300 mM KC1 or after separation from the low molecular weight cytosol constituents, the complex was activated at the same rate in both solvents. Deactivation (time dependent loss of DNA-binding capacity) was much faster in ordinary than in heavy water regardless of gel filtration or the presence ofmore » KC1. A model of receptor activation-deactivation was constructed on the basis of these data that accounts for the observed kinetic deuterium isotope effects and reveals some submolecular details of the process.« less

  9. Down-regulation of parathyroid hormone (PTH) receptors in cultured bone cells is associated with agonist-specific intracellular processing of PTH-receptor complexes.

    PubMed

    Teitelbaum, A P; Silve, C M; Nyiredy, K O; Arnaud, C D

    1986-02-01

    Exposure of cultured embryonic chicken bone cells to the PTH agonists bovine (b) PTH-(1-34) and [8Nle, 18Nle, 34Tyr]bPTH-(1-34)amide [bPTH-(1-34)A] reduces the subsequent cAMP response to the hormone and decreases the specific binding of 125I-labeled PTH to these cultures. To determine whether PTH receptor down-regulation in cultured bone cells is mediated by cellular internalization of PTH-receptor complexes, we measured the uptake of [125I]bPTH-(1-34) into an acid-resistant compartment. Uptake of radioactivity into this compartment was inhibited by incubating cells at 4 C with phenylarsineoxide and unlabeled bPTH-(1-34). Tracer uptake into the acid-resistant compartment at any time was directly proportional to total cell binding at 22 C. Thus, it is likely that PTH-receptor complexes are internalized by bone cells. This mechanism may explain the loss of cell surface receptors after PTH pretreatment. To determine whether internalized PTH-receptor complexes are reinserted into the plasma membrane, we measured PTH binding and PTH stimulation of cAMP production after cells were exposed to monensin, a known inhibitor of receptor recycling. Monensin (25 microM) had no effect on PTH receptor number or affinity and did not alter PTH-stimulated cAMP accumulation. However, monensin (25 microM) incubated with cells pretreated with various concentrations of bPTH-(1-34) for 1 h potentiated the effect of the hormone to reduce subsequent [125I]bPTH-(1-34) binding and PTH-stimulated cAMP accumulation by more than 2 orders of magnitude. Chloroquine also potentiated PTH-induced down-regulation of PTH receptors. By contrast, neither agent influenced PTH binding or PTH-stimulated cAMP production in cells pretreated with the antagonist bPTH-(3-34)A. Thus, monensin potentiated PTH receptor loss only in cells pretreated with PTH agonists, indicating that antagonist-occupied receptors may be processed differently from agonist-occupied receptors in bone cells. The data further suggest

  10. Characterization of human glucocorticoid receptor complexes formed with DNA fragments containing or lacking glucocorticoid response elements

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Tully, D.B.; Cidlowski, J.A.

    1989-03-07

    Sucrose density gradient shift assays were used to study the interactions of human glucocorticoid receptors (GR) with small DNA fragments either containing or lacking glucocorticoid response element (GRE) DNA consensus sequences. When crude cytoplasmic extracts containing ({sup 3}H)triamcinolone acetonide (({sup 3}H)TA) labeled GR were incubated with unlabeled DNA under conditions of DNA excess, a GRE-containing DNA fragment obtained from the 5' long terminal repeat of mouse mammary tumor virus (MMTV LTR) formed a stable 12-16S complex with activated, but not nonactivated, ({sup 3}H)TA receptor. By contrast, if the cytosols were treated with calf thymus DNA-cellulose to deplete non-GR-DNA-binding proteins priormore » to heat activation, a smaller 7-10S complex was formed with the MMTV LTR DNA fragment. Activated ({sup 3}H)TA receptor from DNA-cellulose pretreated cytosols also interacted with two similarly sized fragments from pBR322 DNA. Stability of the complexes formed between GR and these three DNA fragments was strongly affected by even moderate alterations in either the salt concentration or the pH of the gradient buffer. Under all conditions tested, the complex formed with the MMTV LTR DNA fragment was more stable than the complexes formed with either of the pBR322 DNA fragments. Together these observations indicate that the formation of stable complexes between activated GR and isolated DNA fragments requires the presence of GRE consensus sequences in the DNA.« less

  11. Effect of dexamethasone on expression of glucocorticoid receptor in human monocyte cell line THP-1.

    PubMed

    Li, Bo; Bai, Xiangjun; Wanh, Haiping

    2006-01-01

    The effect of dexamethasone with different concentrations and different stimulating periods on the expression of glucocorticoid receptors (GRalpha, GRbeta) protein was investigated in human monocyte cell line THP-1. The cultured human monocyte line THP-1 cells were stimulated by dexamethasone with different concentrations and different periods. The expression of GRalpha and GRbeta protein was detected by Western blotting. The results showed that the expression of GRalpha and GRbeta was detected in the THP-1 cells. The quantity of GRalpha expression was reduced by dexamethasone under the same concentration with the prolongation of the stimulating periods. The quantity of GRbeta expression was increased by dexamethasone treatment in a time- and dose-dependent manner. It was concluded that dexamethasone stimulation time-dependently reduced the GRalpha expression in THP-1 cells. Dexamethasone stimulation time- and dose-dependently increased the GRbeta expression in THP-1 cells. The expression of GRalpha and GRbeta was regulated by glucocorticoid.

  12. Overexpression of Glucocorticoid Receptor β Enhances Myogenesis and Reduces Catabolic Gene Expression

    PubMed Central

    Hinds, Terry D.; Peck, Bailey; Shek, Evan; Stroup, Steven; Hinson, Jennifer; Arthur, Susan; Marino, Joseph S.

    2016-01-01

    Unlike the glucocorticoid receptor α (GRα), GR β (GRβ) has a truncated ligand-binding domain that prevents glucocorticoid binding, implicating GRα as the mediator of glucocorticoid-induced skeletal muscle loss. Because GRβ causes glucocorticoid resistance, targeting GRβ may be beneficial in impairing muscle loss as a result of GRα activity. The purpose of this study was to determine how the overexpression of GRβ affects myotube formation and dexamethasone (Dex) responsiveness. We measured GR isoform expression in C2C12 muscle cells in response to Dex and insulin, and through four days of myotube formation. Next, lentiviral-mediated overexpression of GRβ in C2C12 was performed, and these cells were characterized for cell fusion and myotube formation, as well as sensitivity to Dex via the expression of ubiquitin ligases. GRβ overexpression increased mRNA levels of muscle regulatory factors and enhanced proliferation in myoblasts. GRβ overexpressing myotubes had an increased fusion index. Myotubes overexpressing GRβ had lower forkhead box O3 (Foxo3a) mRNA levels and a blunted muscle atrophy F-box/Atrogen-1 (MAFbx) and muscle ring finger 1 (MuRF1) response to Dex. We showed that GRβ may serve as a pharmacological target for skeletal muscle growth and protection from glucocorticoid-induced catabolic signaling. Increasing GRβ levels in skeletal muscle may cause a state of glucocorticoid resistance, stabilizing muscle mass during exposure to high doses of glucocorticoids. PMID:26875982

  13. Overexpression of Glucocorticoid Receptor β Enhances Myogenesis and Reduces Catabolic Gene Expression.

    PubMed

    Hinds, Terry D; Peck, Bailey; Shek, Evan; Stroup, Steven; Hinson, Jennifer; Arthur, Susan; Marino, Joseph S

    2016-02-11

    Unlike the glucocorticoid receptor α (GRα), GR β (GRβ) has a truncated ligand-binding domain that prevents glucocorticoid binding, implicating GRα as the mediator of glucocorticoid-induced skeletal muscle loss. Because GRβ causes glucocorticoid resistance, targeting GRβ may be beneficial in impairing muscle loss as a result of GRα activity. The purpose of this study was to determine how the overexpression of GRβ affects myotube formation and dexamethasone (Dex) responsiveness. We measured GR isoform expression in C₂C12 muscle cells in response to Dex and insulin, and through four days of myotube formation. Next, lentiviral-mediated overexpression of GRβ in C₂C12 was performed, and these cells were characterized for cell fusion and myotube formation, as well as sensitivity to Dex via the expression of ubiquitin ligases. GRβ overexpression increased mRNA levels of muscle regulatory factors and enhanced proliferation in myoblasts. GRβ overexpressing myotubes had an increased fusion index. Myotubes overexpressing GRβ had lower forkhead box O3 (Foxo3a) mRNA levels and a blunted muscle atrophy F-box/Atrogen-1 (MAFbx) and muscle ring finger 1 (MuRF1) response to Dex. We showed that GRβ may serve as a pharmacological target for skeletal muscle growth and protection from glucocorticoid-induced catabolic signaling. Increasing GRβ levels in skeletal muscle may cause a state of glucocorticoid resistance, stabilizing muscle mass during exposure to high doses of glucocorticoids.

  14. Role of the chromatin landscape and sequence in determining cell type-specific genomic glucocorticoid receptor binding and gene regulation.

    PubMed

    Love, Michael I; Huska, Matthew R; Jurk, Marcel; Schöpflin, Robert; Starick, Stephan R; Schwahn, Kevin; Cooper, Samantha B; Yamamoto, Keith R; Thomas-Chollier, Morgane; Vingron, Martin; Meijsing, Sebastiaan H

    2017-02-28

    The genomic loci bound by the glucocorticoid receptor (GR), a hormone-activated transcription factor, show little overlap between cell types. To study the role of chromatin and sequence in specifying where GR binds, we used Bayesian modeling within the universe of accessible chromatin. Taken together, our results uncovered that although GR preferentially binds accessible chromatin, its binding is biased against accessible chromatin located at promoter regions. This bias can only be explained partially by the presence of fewer GR recognition sequences, arguing for the existence of additional mechanisms that interfere with GR binding at promoters. Therefore, we tested the role of H3K9ac, the chromatin feature with the strongest negative association with GR binding, but found that this correlation does not reflect a causative link. Finally, we find a higher percentage of promoter-proximal GR binding for genes regulated by GR across cell types than for cell type-specific target genes. Given that GR almost exclusively binds accessible chromatin, we propose that cell type-specific regulation by GR preferentially occurs via distal enhancers, whose chromatin accessibility is typically cell type-specific, whereas ubiquitous target gene regulation is more likely to result from binding to promoter regions, which are often accessible regardless of cell type examined. © The Author(s) 2016. Published by Oxford University Press on behalf of Nucleic Acids Research.

  15. Hippocampal ripples down-regulate synapses.

    PubMed

    Norimoto, Hiroaki; Makino, Kenichi; Gao, Mengxuan; Shikano, Yu; Okamoto, Kazuki; Ishikawa, Tomoe; Sasaki, Takuya; Hioki, Hiroyuki; Fujisawa, Shigeyoshi; Ikegaya, Yuji

    2018-03-30

    The specific effects of sleep on synaptic plasticity remain unclear. We report that mouse hippocampal sharp-wave ripple oscillations serve as intrinsic events that trigger long-lasting synaptic depression. Silencing of sharp-wave ripples during slow-wave states prevented the spontaneous down-regulation of net synaptic weights and impaired the learning of new memories. The synaptic down-regulation was dependent on the N -methyl-d-aspartate receptor and selective for a specific input pathway. Thus, our findings are consistent with the role of slow-wave states in refining memory engrams by reducing recent memory-irrelevant neuronal activity and suggest a previously unrecognized function for sharp-wave ripples. Copyright © 2018 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

  16. Context-dependent memory following recurrent hypoglycaemia in non-diabetic rats is mediated via glucocorticoid signalling in the dorsal hippocampus.

    PubMed

    Osborne, Danielle M; O'Leary, Kelsey E; Fitzgerald, Dennis P; George, Alvin J; Vidal, Michael M; Anderson, Brian M; McNay, Ewan C

    2017-01-01

    Recurrent hypoglycaemia is primarily caused by repeated over-administration of insulin to patients with diabetes. Although cognition is impaired during hypoglycaemia, restoration of euglycaemia after recurrent hypoglycaemia is associated with improved hippocampally mediated memory. Recurrent hypoglycaemia alters glucocorticoid secretion in response to hypoglycaemia; glucocorticoids are well established to regulate hippocampal processes, suggesting a possible mechanism for recurrent hypoglycaemia modulation of subsequent cognition. We tested the hypothesis that glucocorticoids within the dorsal hippocampus might mediate the impact of recurrent hypoglycaemia on hippocampal cognitive processes. We characterised changes in the dorsal hippocampus at several time points to identify specific mechanisms affected by recurrent hypoglycaemia, using a well-validated 3 day model of recurrent hypoglycaemia either alone or with intrahippocampal delivery of glucocorticoid (mifepristone) and mineralocorticoid (spironolactone) receptor antagonists prior to each hypoglycaemic episode. Recurrent hypoglycaemia enhanced learning and also increased hippocampal expression of glucocorticoid receptors, serum/glucocorticoid-regulated kinase 1, cyclic AMP response element binding (CREB) phosphorylation, and plasma membrane levels of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) and N-methyl-D-aspartic acid (NMDA) receptors. Both hippocampus-dependent memory enhancement and the molecular changes were reversed by glucocorticoid receptor antagonist treatment. These results indicate that increased glucocorticoid signalling during recurrent hypoglycaemia produces several changes in the dorsal hippocampus that are conducive to enhanced hippocampus-dependent contextual learning. These changes appear to be adaptive, and in addition to supporting cognition may reduce damage otherwise caused by repeated exposure to severe hypoglycaemia.

  17. Internalization and Down-Regulation of the ALK Receptor in Neuroblastoma Cell Lines upon Monoclonal Antibodies Treatment

    PubMed Central

    Mazot, Pierre; Cazes, Alex; Dingli, Florent; Degoutin, Joffrey; Irinopoulou, Théano; Boutterin, Marie-Claude; Lombard, Bérangère; Loew, Damarys; Hallberg, Bengt; Palmer, Ruth Helen; Delattre, Olivier

    2012-01-01

    Recently, activating mutations of the full length ALK receptor, with two hot spots at positions F1174 and R1275, have been characterized in sporadic cases of neuroblastoma. Here, we report similar basal patterns of ALK phosphorylation between the neuroblastoma IMR-32 cell line, which expresses only the wild-type receptor (ALKWT), and the SH-SY5Y cell line, which exhibits a heterozygous ALK F1174L mutation and expresses both ALKWT and ALKF1174L receptors. We demonstrate that this lack of detectable increased phosphorylation in SH-SY5Y cells is a result of intracellular retention and proteasomal degradation of the mutated receptor. As a consequence, in SH-SY5Y cells, plasma membrane appears strongly enriched for ALKWT whereas both ALKWT and ALKF1174L were present in intracellular compartments. We further explored ALK receptor trafficking by investigating the effect of agonist and antagonist mAb (monoclonal antibodies) on ALK internalization and down-regulation, either in SH-SY5Y cells or in cells expressing only ALKWT. We observe that treatment with agonist mAbs resulted in ALK internalization and lysosomal targeting for receptor degradation. In contrast, antagonist mAb induced ALK internalization and recycling to the plasma membrane. Importantly, we correlate this differential trafficking of ALK in response to mAb with the recruitment of the ubiquitin ligase Cbl and ALK ubiquitylation only after agonist stimulation. This study provides novel insights into the mechanisms regulating ALK trafficking and degradation, showing that various ALK receptor pools are regulated by proteasome or lysosome pathways according to their intracellular localization. PMID:22479414

  18. Differential modulation of glucocorticoid action by FK506 in A549 cells.

    PubMed Central

    Croxtall, Jamie D; Paul-Clark, Mark; Van Hal, Peter Th W

    2003-01-01

    Glucocorticoids inhibit the release of eicosanoid pro-inflammatory mediators. The immunosuppressant FK506 is known to enhance many aspects of glucocorticoid action. In the present study we show that FK506 (1 microM or 10 microM) inhibits the release of arachidonic acid and prostaglandin E2 from A549 cells and also inhibits their proliferation. Simultaneous treatment of FK506 together with the glucocorticoids dexamethasone, methyl-prednisolone, fluticasone or mometasone (10 nM) enhances the growth inhibitory effect of these steroids. Furthermore, the simultaneous use of FK506 and these glucocorticoids similarly results in enhanced inhibition of arachidonic acid release. When pretreated for 2 h, FK506 enhances glucocorticoid inhibition of COX2 (cyclo-oxygenase 2) expression. However, when administered simultaneously, FK506 blocks glucocorticoid inhibition of COX2 expression. Nuclear uptake of glucocorticoid receptors mediated by glucocorticoids is also blocked by the simultaneous administration of FK506. These results suggest that the effect of simultaneous treatment of FK506 with glucocorticoids differs significantly from that where pre-treatment of the immunosuppressant is used. Recently, immunophilin interchange has been identified as a first step in glucocorticoid receptor activation following ligand activation. We show here that the FKB51 (FK506-binding protein 51)-FKB52 switch is differentially regulated by glucocorticoid and FK506 treatment strategy. PMID:12948397

  19. Glucocorticoid acts on a putative G protein-coupled receptor to rapidly regulate the activity of NMDA receptors in hippocampal neurons.

    PubMed

    Zhang, Yanmin; Sheng, Hui; Qi, Jinshun; Ma, Bei; Sun, Jihu; Li, Shaofeng; Ni, Xin

    2012-04-01

    Glucocorticoids (GCs) have been demonstrated to act through both genomic and nongenomic mechanisms. The present study demonstrated that corticosterone rapidly suppressed the activity of N-methyl-D-aspartate (NMDA) receptors in cultured hippocampal neurons. The effect was maintained with corticosterone conjugated to bovine serum albumin and blocked by inhibition of G protein activity with intracellular GDP-β-S application. Corticosterone increased GTP-bound G(s) protein and cyclic AMP (cAMP) production, activated phospholipase Cβ(3) (PLC-β(3)), and induced inositol-1,4,5-triphosphate (IP(3)) production. Blocking PLC and the downstream cascades with PLC inhibitor, IP(3) receptor antagonist, Ca(2+) chelator, and protein kinase C (PKC) inhibitors prevented the actions of corticosterone. Blocking adenylate cyclase (AC) and protein kinase A (PKA) caused a decrease in NMDA-evoked currents. Application of corticosterone partly reversed the inhibition of NMDA currents caused by blockage of AC and PKA. Intracerebroventricular administration of corticosterone significantly suppressed long-term potentiation (LTP) in the CA1 region of the hippocampus within 30 min in vivo, implicating the possibly physiological significance of rapid effects of GC on NMDA receptors. Taken together, our results indicate that GCs act on a putative G protein-coupled receptor to activate multiple signaling pathways in hippocampal neurons, and the rapid suppression of NMDA activity by GCs is dependent on PLC and downstream signaling.

  20. The herpes simplex virus receptor nectin-1 is down-regulated after trans-interaction with glycoprotein D

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Stiles, Katie M.; Center for Oral Health Research, School of Dental Medicine University of Pennsylvania, Philadelphia, PA 19104; Milne, Richard S.B.

    2008-03-30

    During herpes simplex virus (HSV) entry, membrane fusion occurs either on the cell surface or after virus endocytosis. In both cases, binding of glycoprotein D (gD) to a receptor such as nectin-1 or HVEM is required. In this study, we co-cultured cells expressing gD with nectin-1 expressing cells to investigate the effects of gD on nectin-1 at cell contacts. After overnight co-cultures with gD expressing cells, there was a down-regulation of nectin-1 in B78H1-C10, SY5Y, A431 and HeLa cells, which HSV enters by endocytosis. In contrast, on Vero cells, which HSV enters at the plasma membrane, nectin-1 was not down-regulated.more » Further analysis of B78H1-derived cells showed that nectin-1 down-regulation corresponds to the ability of gD to bind nectin-1 and is achieved by internalization and low-pH-dependent degradation of nectin-1. Moreover, gD is necessary for virion internalization in B78H1 cells expressing nectin-1. These data suggest that the determinants of gD-mediated internalization of nectin-1 may direct HSV to an endocytic pathway during entry.« less

  1. Diurnal suppression of EGFR signalling by glucocorticoids and implications for tumour progression and treatment.

    PubMed

    Lauriola, Mattia; Enuka, Yehoshua; Zeisel, Amit; D'Uva, Gabriele; Roth, Lee; Sharon-Sevilla, Michal; Lindzen, Moshit; Sharma, Kirti; Nevo, Nava; Feldman, Morris; Carvalho, Silvia; Cohen-Dvashi, Hadas; Kedmi, Merav; Ben-Chetrit, Nir; Chen, Alon; Solmi, Rossella; Wiemann, Stefan; Schmitt, Fernando; Domany, Eytan; Yarden, Yosef

    2014-10-03

    Signal transduction by receptor tyrosine kinases (RTKs) and nuclear receptors for steroid hormones is essential for body homeostasis, but the cross-talk between these receptor families is poorly understood. We observed that glucocorticoids inhibit signalling downstream of EGFR, an RTK. The underlying mechanism entails suppression of EGFR's positive feedback loops and simultaneous triggering of negative feedback loops that normally restrain EGFR. Our studies in mice reveal that the regulation of EGFR's feedback loops by glucocorticoids translates to circadian control of EGFR signalling: EGFR signals are suppressed by high glucocorticoids during the active phase (night-time in rodents), while EGFR signals are enhanced during the resting phase. Consistent with this pattern, treatment of animals bearing EGFR-driven tumours with a specific kinase inhibitor was more effective if administered during the resting phase of the day, when glucocorticoids are low. These findings support a circadian clock-based paradigm in cancer therapy.

  2. A membrane glucocorticoid receptor mediates the rapid/non-genomic actions of glucocorticoids in mammalian skeletal muscle fibres

    PubMed Central

    Pérez, María Hernández-Alcalá; Cormack, Jonathan; Mallinson, David; Mutungi, Gabriel

    2013-01-01

    Glucocorticoids (GCs) are steroid hormones released from the adrenal gland in response to stress. They are also some of the most potent anti-inflammatory and immunosuppressive drugs currently in clinical use. They exert most of their physiological and pharmacological actions through the classical/genomic pathway. However, they also have rapid/non-genomic actions whose physiological and pharmacological functions are still poorly understood. Therefore, the primary aim of this study was to investigate the rapid/non-genomic effects of two widely prescribed glucocorticoids, beclomethasone dipropionate (BDP) and prednisolone acetate (PDNA), on force production in isolated, intact, mouse skeletal muscle fibre bundles. The results show that the effects of both GCs on maximum isometric force (Po) were fibre-type dependent. Thus, they increased Po in the slow-twitch fibre bundles without significantly affecting that of the fast-twitch fibre bundles. The increase in Po occurred within 10 min and was insensitive to the transcriptional inhibitor actinomycin D. Also, it was maximal at ∼250 nm and was blocked by the glucocorticoid receptor (GCR) inhibitor RU486 and a monoclonal anti-GCR, suggesting that it was mediated by a membrane (m) GCR. Both muscle fibre types expressed a cytosolic GCR. However, a mGCR was present only in the slow-twitch fibres. The receptor was more abundant in oxidative than in glycolytic fibres and was confined mainly to the periphery of the fibres where it co-localised with laminin. From these findings we conclude that the rapid/non-genomic actions of GCs are mediated by a mGCR and that they are physiologically/therapeutically beneficial, especially in slow-twitch muscle fibres. PMID:23878367

  3. A membrane glucocorticoid receptor mediates the rapid/non-genomic actions of glucocorticoids in mammalian skeletal muscle fibres.

    PubMed

    Pérez, María Hernández-Alcalá; Cormack, Jonathan; Mallinson, David; Mutungi, Gabriel

    2013-10-15

    Glucocorticoids (GCs) are steroid hormones released from the adrenal gland in response to stress. They are also some of the most potent anti-inflammatory and immunosuppressive drugs currently in clinical use. They exert most of their physiological and pharmacological actions through the classical/genomic pathway. However, they also have rapid/non-genomic actions whose physiological and pharmacological functions are still poorly understood. Therefore, the primary aim of this study was to investigate the rapid/non-genomic effects of two widely prescribed glucocorticoids, beclomethasone dipropionate (BDP) and prednisolone acetate (PDNA), on force production in isolated, intact, mouse skeletal muscle fibre bundles. The results show that the effects of both GCs on maximum isometric force (Po) were fibre-type dependent. Thus, they increased Po in the slow-twitch fibre bundles without significantly affecting that of the fast-twitch fibre bundles. The increase in Po occurred within 10 min and was insensitive to the transcriptional inhibitor actinomycin D. Also, it was maximal at ∼250 nM and was blocked by the glucocorticoid receptor (GCR) inhibitor RU486 and a monoclonal anti-GCR, suggesting that it was mediated by a membrane (m) GCR. Both muscle fibre types expressed a cytosolic GCR. However, a mGCR was present only in the slow-twitch fibres. The receptor was more abundant in oxidative than in glycolytic fibres and was confined mainly to the periphery of the fibres where it co-localised with laminin. From these findings we conclude that the rapid/non-genomic actions of GCs are mediated by a mGCR and that they are physiologically/therapeutically beneficial, especially in slow-twitch muscle fibres.

  4. Histone Deacetylase 6 (HDAC6) Is an Essential Modifier of Glucocorticoid-Induced Hepatic Gluconeogenesis

    PubMed Central

    Winkler, Robin; Benz, Verena; Clemenz, Markus; Bloch, Mandy; Foryst-Ludwig, Anna; Wardat, Sami; Witte, Nicole; Trappiel, Manuela; Namsolleck, Pawel; Mai, Knut; Spranger, Joachim; Matthias, Gabriele; Roloff, Tim; Truee, Oliver; Kappert, Kai; Schupp, Michael; Matthias, Patrick; Kintscher, Ulrich

    2012-01-01

    In the current study, we investigated the importance of histone deacetylase (HDAC)6 for glucocorticoid receptor–mediated effects on glucose metabolism and its potential as a therapeutic target for the prevention of glucocorticoid-induced diabetes. Dexamethasone-induced hepatic glucose output and glucocorticoid receptor translocation were analyzed in wild-type (wt) and HDAC6-deficient (HDAC6KO) mice. The effect of the specific HDAC6 inhibitor tubacin was analyzed in vitro. wt and HDAC6KO mice were subjected to 3 weeks’ dexamethasone treatment before analysis of glucose and insulin tolerance. HDAC6KO mice showed impaired dexamethasone-induced hepatic glucocorticoid receptor translocation. Accordingly, dexamethasone-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 dexamethasone-induced whole-body glucose intolerance as well as insulin resistance in HDAC6KO mice compared with wt littermates was observed. This study demonstrates that HDAC6 is an essential regulator of hepatic glucocorticoid-stimulated gluconeogenesis and impairment of whole-body glucose metabolism through modification of glucocorticoid receptor nuclear translocation. Selective pharmacological inhibition of HDAC6 may provide a future therapeutic option against the prodiabetogenic actions of glucocorticoids. PMID:22210316

  5. Ionotropic and metabotropic glutamate receptor mediation of glucocorticoid-induced apoptosis in hippocampal cells and the neuroprotective role of synaptic N-methyl-D-aspartate receptors.

    PubMed

    Lu, J; Goula, D; Sousa, N; Almeida, O F X

    2003-01-01

    Glutamate receptors have been proposed to mediate the apoptotic actions of glucocorticoids in hippocampal cells. To further analyze the role of glutamate receptors in this process, we pretreated primary hippocampal cells from neonatal (postnatal day 4) rats with antagonists of ionotropic glutamate receptor (iGluR) and metabotropic glutamate receptor (mGluR) antagonists before exposure to the specific glucocorticoid receptor agonist dexamethasone (DEX) at a dose of 1 microM. Dizocilpine (MK801; a general N-methyl-D-aspartic acid [NMDA] receptor antagonist, NMDAR antagonist) and ifenprodil (a specific ligand of the NMDAR 2B subunit, NR2B), were used to block iGluR; (RS)-alpha-ethyl-4-carboxyphenylglycine (E4CPG) and (RS)-alpha-cyclopropyl-4-phosphonophenyl-glycine (CPPG) were employed as I/II (E4CPG) and II/III (CPPG) mGluR antagonists. Blockade of iGluR resulted in a significant attenuation of DEX-induced cell death; the finding that ifenprodil exerted a similar potency to MK801 demonstrates the involvement of NR2B receptors in glucocorticoid-induced cell death. Apoptosis accounted for a significant amount of the cell loss observed, as detected by terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling histochemistry for the in situ labeling of DNA breaks; apoptotic cells were distinguished from necrosis on the basis of morphological criteria, including chromatin condensation, membrane blebbing and presence of apoptotic bodies. Treatment with E4CPG and CPPG completely abolished the apoptotic response to DEX, thus showing the additional contribution of mGluR to the phenomenon. Further, dose-response studies with NMDA revealed that whereas high (10 microM) doses of NMDA themselves elicit cytotoxic responses, low (1-5 microM) concentrations of NMDA can effectively oppose DEX-induced cell death. Interestingly, the neuroprotective actions of low dose NMDA stimulation were abolished when either synaptic or extrasynaptic NMDA receptors were blocked with MK801

  6. Isoform composition and stoichiometry of the approx. 90-kDa heat shock protein associated with glucocorticoid receptors

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Mendel, D.B.; Orti, E.

    1988-05-15

    The authors observed that the approx. 90-kDa non-steroid-binding component of nonactivated glucocorticoid receptors purified from WEHI-7 mouse thymoma cells (which has been identified as the approx. 90-kDa heat shock protein) consistently migrates as a doublet during polyacrylamide gel electrophoresis under denaturing and reducing conditions. It has recently been reported that murine Meth A cells contain a tumor-specific transplantation antigen (TSTA) which is related or identical to the approx. 90-kDa heat shock protein. The observation that TSTA and the approx. 90-kDa heat shock protein isolated from these cells exists as two isoforms of similar molecular mass and charge has suggested thatmore » the doublet observed is also due to the existence of two isoforms. They have therefore conducted this study to determine whether TSTA and the approx. 90-kDa component of glucocorticoid receptors are indeed related, to establish whether the receptor preferentially binds one isoform of the approx. 90-kDa heat shock protein, and to investigate the stoichiometry of the nonactivated receptor complex. They used the BuGr1 and AC88 monoclonal antibodies to purify, respectively, receptor-associated and free approx. 90-kDa heat shock protein from WEHI-7 cells grown for 48 h with (/sup 35/S)methionine to metabolically label proteins to steady state. The long-term metabolic labeling approach has also enabled them to directly determine that the purified non-activated glucocorticoid receptor contains a single steroid-binding protein and two approx. 90-kDa non-steroid-binding subunits. The consistency with which a approx. 1:2 stoichiometric ratio of steroid binding to approx. 90-kDa protein is observed supports the view that the approx. 90-kDa heat shock protein is a true component of nonactivated glucocorticoid-receptor complexes.« less

  7. Circadian glucocorticoid oscillations promote learning-dependent synapse formation and maintenance

    PubMed Central

    Liston, Conor; Cichon, Joseph M; Jeanneteau, Freddy; Jia, Zhengping; Chao, Moses V; Gan, Wen-Biao

    2013-01-01

    Excessive glucocorticoid exposure during chronic stress causes synapse loss and learning impairment. Under normal physiological conditions, glucocorticoid activity oscillates in synchrony with the circadian rhythm. Whether and how endogenous glucocorticoid oscillations modulate synaptic plasticity and learning is unknown. Here we show that circadian glucocorticoid peaks promote postsynaptic dendritic spine formation in the mouse cortex after motor skill learning, whereas troughs are required for stabilizing newly formed spines that are important for long-term memory retention. Conversely, chronic and excessive exposure to glucocorticoids eliminates learning-associated new spines and disrupts previously acquired memories. Furthermore, we show that glucocorticoids promote rapid spine formation through a non-transcriptional mechanism by means of the LIM kinase–cofilin pathway and increase spine elimination through transcriptional mechanisms involving mineralocorticoid receptor activation. Together, these findings indicate that tightly regulated circadian glucocorticoid oscillations are important for learning-dependent synaptic formation and maintenance. They also delineate a new signaling mechanism underlying these effects. PMID:23624512

  8. Downregulation of spinal glutamate transporter EAAC1 following nerve injury is regulated by central glucocorticoid receptors in rats.

    PubMed

    Wang, Shuxing; Lim, Grewo; Yang, Liling; Sung, Backil; Mao, Jianren

    2006-01-01

    Previous studies have shown that glucocorticoid receptors (GR) were upregulated, whereas glutamate transporters were downregulated, within the spinal cord dorsal horn after peripheral nerve injury. However, the relationship between the expression of spinal GR and glutamate transporter after nerve injury remains unknown. In the present study, we examined the hypothesis that central GR would regulate the expression of spinal glutamate transporter EAAC1 following chronic constriction nerve injury (CCI) in rats. CCI induced a significant downregulation of EAAC1 expression primarily within the ipsilateral spinal cord dorsal horn when examined on postoperative day 7 using both Western blot and immunohistochemistry. The downregulation of EAAC1 was significantly diminished after either the GR antagonist RU38486 (4 > 2 = 0.5 microg = vehicle) or a GR antisense oligonucleotide was administered intrathecally twice daily for postoperative day 1-6. Moreover, CCI induced a significant downregulation of nuclear factor kappaB (NF-kappaB) within the ipsilateral spinal cord dorsal horn, which also was attenuated by either RU38486 (4 > 2 = 0.5 microg = vehicle) or a GR antisense oligonucleotide. The immunohistochemical data indicated a pattern of colocalization between GR and EAAC1 as well as GR and NF-kappaB within the spinal cord dorsal horn. Since, NF-kappaB has been shown to regulate the expression of those cellular elements linked to inflammation and tissue injury and its activity can be negatively regulated by GR activation, these results suggest that spinal GR through NF-kappaB may play a significant role in the regulation of EAAC1 expression after peripheral nerve injury, a cellular pathway that may contribute to the development of neuropathic pain behaviors in rats.

  9. Context-dependent memory following recurrent hypoglycaemia in non-diabetic rats is mediated via glucocorticoid signalling in the dorsal hippocampus

    PubMed Central

    Osborne, Danielle M.; O'Leary, Kelsey E.; Fitzgerald, Dennis P.; George, Alvin J.; Vidal, Michael M.; Anderson, Brian M.; McNay, Ewan C.

    2016-01-01

    Aims/hypothesis Recurrent hypoglycaemia is primarily caused by repeated over-administration of insulin to patients with diabetes. Although cognition is impaired during hypoglycaemia, restoration of euglycaemia after recurrent hypoglycaemia is associated with improved hippocampally mediated memory. Recurrent hypoglycaemia alters glucocorticoid secretion in response to hypoglycaemia; glucocorticoids are well established to regulate hippocampal processes, suggesting a possible mechanism for recurrent hypoglycaemia modulation of subsequent cognition. We tested the hypothesis that glucocorticoids within the dorsal hippocampus might mediate the impact of recurrent hypoglycaemia on hippocampal cognitive processes. Methods We characterised changes in the dorsal hippocampus at several time points to identify specific mechanisms affected by recurrent hypoglycaemia, using a well-validated 3 day model of recurrent hypoglycaemia either alone or with intrahippocampal delivery of glucocorticoid (mifepristone) and mineralocorticoid (spironolactone) receptor antagonists prior to each hypoglycaemic episode. Results Recurrent hypoglycaemia enhanced learning and also increased hippocampal expression of glucocorticoid receptors, serum/glucocorticoid-regulated kinase 1, cyclic AMP response element binding (CREB) phosphorylation, and plasma membrane levels of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) and N-methyl-d-aspartic acid (NMDA) receptors. Both hippocampus-dependent memory enhancement and the molecular changes were reversed by glucocorticoid receptor antagonist treatment. Conclusions/interpretation These results indicate that increased glucocorticoid signalling during recurrent hypoglycaemia produces several changes in the dorsal hippocampus that are conducive to enhanced hippocampus-dependent contextual learning. These changes appear to be adaptive, and in addition to supporting cognition may reduce damage otherwise caused by repeated exposure to severe

  10. Involvement of miR17 pathway in glucocorticoid-induced cell death in pediatric acute lymphoblastic leukemia.

    PubMed

    Harada, Masako; Pokrovskaja-Tamm, Katja; Söderhäll, Stefan; Heyman, Mats; Grander, Dan; Corcoran, Martin

    2012-10-01

    Analysis of the microRNA transcriptome following dexa- methasone treatment of the acute lymphocytic leukemia (ALL) cell line RS4;11 showed a global down-regulation of microRNA levels. MIR17HG was rapidly down-regulated following treatment, with chromatin immunoprecipitation (ChIP) analysis demonstrating the promoter to be a direct target of glucocorticoid (GC)-transcriptional repression and revealing the miR17-92 cluster as a prime target for dexamethasone-induced repression. The loss of miR17 family expression and concomitant increases in the miR17 target Bim occurred in an additional ALL cell line SUP-B15 but not in the dexamethasone-resistant REH. Alteration of miR17 levels through up-regulation or inhibition resulted in an decrease and increase, respectively, in Bim protein levels and dexamethasone-induced cell death. Primary ex vivo ALL cells that underwent apoptosis induced by dexamethasone also down-regulated miR17 levels. Thus, down-regulation of miR17 plays an important role in glucocorticoid-induced cell death suggesting that targeting miR17 may improve the current ALL combination therapy.

  11. An effective fixative for glucocorticoid receptors in fetal tissues

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Koga, T.; Kurisu, K.

    1982-01-01

    As a preliminary study in an autoradiographic study of glucocorticoid (GC) receptor localization in orofacial tissues of mouse fetuses, a search was made to determine the most effective fixative for preservation of the GC-receptor complex. Twelve-day-old mouse fetuses were administered tritiated triamcinolone acetonide (/sup 3/H-TAC) intraamniotically and subsequently processed by one of the following three procedures: freeze-drying, prefixation with Karnovsky's fixative, or the catechin fixative (Karnovsky's fixative containing 1% D-catechin) and postfixation with osmium tetroxide. Light microscopic autoradiography and liquid scintillation counting of the specimens revealed that the catechin fixative gave the best results for fixation of the steroid-receptor complexmore » and preservation of tissue structure. Light and electron microscopic autoradiographic studies of the time course of the localization of /sup 3/H-TAC in palatal shelves supported the catechin fixative as being the most effective in preservation of GC-receptor or ligand complexes.« less

  12. Glucocorticoids: exemplars of multi-tasking

    PubMed Central

    Buckingham, Julia C

    2006-01-01

    Well over 80 years ago Philip Smith described the beneficial clinical effects of adrenocortical extracts in animal models of adrenal insufficiency. In the ensuing years, scientists across the globe have sought to understand the mechanisms by which adrenal hormones and their synthetic analogues produce their complex and varied actions. Particular attention has focused on the glucocorticoids, partly because they have a vital place in the treatment of inflammatory and autoimmune disorders but also because dysregulation of the secretion and/or activity of endogenous glucocorticoids is increasingly implicated in a number of common disorders that pose a growing clinical burden, such as obesity, type II diabetes, the metabolic syndrome, hypertension and depression. This review considers some of the key advances that have been made in our understanding of the physiology, pathology and pharmacology of the glucocorticoids. Emphasis is placed on the molecular mechanisms of glucocorticoid signalling and the complex mechanisms that regulate the access of steroids in the systemic circulation to their receptors in their various target cells and tissues. In addition, consideration is given to the irreversible ‘organisational' actions of glucocorticoids in perinatal life and to the potential role of the steroids in the aetiology of disease. PMID:16402112

  13. Nuclear receptor-mediated regulation of carboxylesterase expression and activity.

    PubMed

    Staudinger, Jeff L; Xu, Chenshu; Cui, Yue J; Klaassen, Curtis D

    2010-03-01

    Emerging evidence demonstrates that several nuclear receptor (NR) family members regulate drug-inducible expression and activity of several important carboxylesterase (CES) enzymes in mammalian liver and intestine. Numerous clinically prescribed anticancer prodrugs, carbamate and pyrethroid insecticides, environmental toxicants and procarcinogens are substrates for CES enzymes. Moreover, a key strategy used in rational drug design frequently utilizes an ester linkage methodology to selectively target a prodrug, or to improve the water solubility of a novel compound. This review summarizes the current state of knowledge regarding NR-mediated regulation of CES enzymes in mammals and highlights their importance in drug metabolism, drug-drug interactions and toxicology. New knowledge regarding the transcriptional regulation of CES enzymes by NR proteins pregnane x receptor (NR1I2) and constitutive androstane receptor (NR1I3) has recently come to light through the use of knockout and transgenic mouse models. Novel insights regarding the species-specific cross-regulation of glucocorticoid receptor (NR3C1) and PPAR-alpha (NR1C1) signaling and CES gene expression are discussed. Elucidation of the role of NR-mediated regulation of CES enzymes in liver and intestine will have a significant impact on rational drug design and the development of novel prodrugs, especially for patients on combination therapy.

  14. Transformation of glucocorticoid receptors bound to the antagonist RU 486: Effects of alkaline phosphatase

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Gruol, D.J.; Wolfe, K.A.

    1990-08-28

    RU 486 is a synthetic steroid that binds avidly to glucocorticoid receptors without promoting their transformation into activated transcription factors. A significant part of this behavior has been shown to be due to a failure of the RU 486 bound receptor to be efficiently released from a larger (sedimenting at 8-9 S) multimeric complex containing the 90-kDa heat shock protein. The studies have found that in vitro at 15{degree}C the RU 486-receptor was slowly released from the 8-9S complex and converted into a DNA binding protein by a process that could be blocked by sodium fluoride. Moreover, this transition wasmore » significantly accelerated by treatment with alkaline phosphatase. High-resolution anion-exchange chromatography showed that the profile of receptor subspecies released from the 8-9S complex was different for the RU 486 bound receptor when compared to the receptor occupied by the agonist triamcinolone acetonide. Production of the earliest eluting receptor form (peak A) was inhibited with RU 486. Treatment of the Ru 486-receptor with alkaline phosphatase increased the formation of the peak A subspecies as well as the capacity of receptor to bind DNA-cellulose. Taken together, the results indicate that phosphorylation of the receptor or a tightly bound factor contributes to defining the capacity with which individual steroids can promote dissociation of the 8-9S complex and conversion of the glucocorticoid receptor into a DNA-binding protein.« less

  15. Probing Dominant Negative Behavior of Glucocorticoid Receptor β through a Hybrid Structural and Biochemical Approach

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Min, Jungki; Perera, Lalith; Krahn, Juno M.

    ABSTRACT Glucocorticoid receptor β (GRβ) is associated with glucocorticoid resistance via dominant negative regulation of GRα. To better understand how GRβ functions as a dominant negative inhibitor of GRα at a molecular level, we determined the crystal structure of the ligand binding domain of GRβ complexed with the antagonist RU-486. The structure reveals that GRβ binds RU-486 in the same ligand binding pocket as GRα, and the unique C-terminal amino acids of GRβ are mostly disordered. Binding energy analysis suggests that these C-terminal residues of GRβ do not contribute to RU-486 binding. Intriguingly, the GRβ/RU-486 complex binds corepressor peptide withmore » affinity similar to that of a GRα/RU-486 complex, despite the lack of helix 12. Our biophysical and biochemical analyses reveal that in the presence of RU-486, GRβ is found in a conformation that favors corepressor binding, potentially antagonizing GRα function. This study thus presents an unexpected molecular mechanism by which GRβ could repress transcription.« less

  16. Gastrin-releasing peptide receptor-induced internalization, down-regulation, desensitization, and growth: possible role for cyclic AMP.

    PubMed

    Benya, R V; Fathi, Z; Kusui, T; Pradhan, T; Battey, J F; Jensen, R T

    1994-08-01

    Stimulation of the gastrin-releasing peptide receptor (GRP-R) in Swiss 3T3 cells resembles that of a number of other recently described G protein-coupled receptors, insofar as both the phospholipase C and adenylyl cyclase signal transduction pathways are activated. GRP-R activation induces numerous alterations in both the cell and the receptor, but because two signal transduction pathways are activated it is difficult to determine the specific contributions of either pathway. We have found that BALB/3T3 fibroblasts transfected with the coding sequence for the GRP-R are pharmacologically indistinguishable from native receptor-expressing cells and activate phospholipase C in a manner similar to that of the native receptor but fail to increase cAMP in response to bombesin; thus, they may be useful cells to explore the role of activation of each pathway in altering cell and receptor function. Swiss 3T3 cells and GRP-R-transfected BALB/3T3 cells expressed identically glycosylated receptors that bound various agonists and antagonists similarly. G protein activation, as determined by evaluation of agonist-induced activation of phospholipase C and by analysis of the effect of guanosine-5'-(beta,gamma-imido)triphosphate on GRP-R binding affinity, was indistinguishable. Agonist stimulation of GRP-R caused similar receptor changes (internalization and down-regulation) and homologous desensitization in both cell types. Bombesin stimulation of Swiss 3T3 cells that had been preincubated with forskolin increased cAMP levels 9-fold, but no bombesin-specific increase in cAMP levels was detected in transfected cells, even though forskolin and cholera toxin increased cAMP levels in these cells. Quiescent Swiss 3T3 cells treated with bombesin rapidly increased c-fos mRNA levels and [3H]thymidine incorporation, whereas both effects were potentiated by forskolin. The specific protein kinase A inhibitor H-89 blocked increases in c-fos levels and [3H]thymidine incorporation induced by low

  17. Glucocorticoids and estrogens modulate the NF-κB pathway differently in the micro- and macrovasculature.

    PubMed

    Edgar, Abarca-Rojano; Judith, Pacheco-Yépez; Elisa, Drago-Serrano Maria; Rafael, Campos-Rodríguez

    2013-12-01

    Estrogens and glucocorticoids have synergistic effects in the micro and macrovasculature of endothelial cells (ECs), having pro-inflammatory effects in the former and inhibiting the expression of adhesion molecules in the latter. The molecular basis of these effects in the endothelium has not yet been clarified. We postulate that the ECs of the micro- and macrovasculature have different non-genomic mechanisms that regulate levels of preexisting complexes of glucocorticoids and estrogens with their respective receptors. Since these receptors are regulated by NF-κB, their expression could be critical to the activation of a pro- or anti-inflammatory response. In the macrovasculature the synergistic effects of estrogens and glucocorticoids on ECs may be through the inhibition of NF-κB, leading to the inhibition of the expression of inflammatory molecules. It seems likely that glucocorticoid-receptor and estrogen-receptor complexes directly bind to NF-κB proteins in the macrovasculature, resulting in the inhibition of an excessive proinflammatory response. Further insights into these processes may help clarify the role of the endothelial cells of different vascular beds during the inflammatory response and chronic inflammation, and thus contribute to the design of more effective therapeutic strategies for the prevention of diseases related to inflammation, including atherosclerosis, systemic lupus erythematosus and rheumatoid arthritis. Copyright © 2013 Elsevier Ltd. All rights reserved.

  18. Zyflamend Sensitizes Tumor Cells to TRAIL-Induced Apoptosis Through Up-Regulation of Death Receptors and Down-Regulation of Survival Proteins: Role of ROS-Dependent CCAAT/Enhancer-Binding Protein-Homologous Protein Pathway

    PubMed Central

    Kim, Ji Hye; Park, Byoungduck; Gupta, Subash C.; Kannappan, Ramaswamy; Sung, Bokyung

    2012-01-01

    Abstract Aim: TNF (tumor necrosis factor)-related apoptosis-inducing ligand (TRAIL), is a selective killer of tumor cells, although its potential is limited by the development of resistance. In this article, we investigated whether the polyherbal preparation Zyflamend® can sensitize tumor cells to TRAIL. Results: We found that Zyflamend potentiated TRAIL-induced apoptosis in human cancer cells. Zyflamend manifested its effects through several mechanisms. First, it down-regulated the expression of cell survival proteins known to be linked to resistance to TRAIL. Second, Zyflamend up-regulated the expression of pro-apoptotic protein, Bax. Third, Zyflamend up-regulated the expression of death receptors (DRs) for TRAIL. Up-regulation of DRs was critical as gene-silencing of these receptors significantly reduced the effect of Zyflamend on TRAIL-induced apoptosis. The up-regulation of DRs was dependent on CCAAT/enhancer-binding protein-homologous protein (CHOP), as Zyflamend induced CHOP, its gene-silencing abolished the induction of receptors, and mutation of the CHOP binding site on DR5 promoter abolished Zyflamend-mediated DR5 transactivation. Zyflamend mediated its effects through reactive oxygen species (ROS), as ROS quenching reduced its effect. Further, Zyflamend induced DR5 and CHOP and down-regulated the expression of cell survival proteins in nude mice bearing human pancreatic cancer cells. Innovation: Zyflamend can sensitize tumor cells to TRAIL through modulation of multiple cell signaling mechanisms that are linked to ROS. Conclusion: Zyflamend potentiates TRAIL-induced apoptosis through the ROS-CHOP-mediated up-regulation of DRs, increase in pro-apoptotic protein and down-regulation of cell survival proteins. Antioxid. Redox Signal. 16, 413–427. PMID:22004570

  19. MicroRNA-29a ameliorates glucocorticoid-induced suppression of osteoblast differentiation by regulating β-catenin acetylation.

    PubMed

    Ko, Jih-Yang; Chuang, Pei-Chin; Chen, Ming-Wen; Ke, Huei-Ching; Wu, Shin-Long; Chang, Yu-Hsuan; Chen, Yu-Shan; Wang, Feng-Sheng

    2013-12-01

    Excess glucocorticoid treatment induces loss of osteoblast differentiation. Post-translational modification of β-catenin reportedly regulates osteogenic activities in bone cells. This study was undertaken to test whether miR-29a signaling regulates the acetylation status of β-catenin in the glucocorticoid-mediated osteoblast dysfunction. Murine osteoblast cultures were incubated under osteogenic conditions with or without supraphysiological glucocorticoid, miR-29a precursor, antisense oligonucleotides or histone deacetylase 4 (HDAC4) RNA interferences. Osteoblast differentiation was determined by alkaline phosphatase activity, calcium deposition, and von Kossa stain. β-Catenin acetylation and miR-29a transcription were detected by immunoblotting, chromatin immunoprecipitation and quantitative PCR. Protein interaction was detected by fluorescence protein ligation assay. Supraphysiological glucocorticoid treatment repressed osteoblast differentiation and induced loss of miR-29a expression and acetylated β-catenin levels in osteoblast cultures. Gain of miR-29a function attenuated the deleterious effects of glucocorticoid on osteogenic gene expression and mineralized nodule formation, whereas knockdown of miR-29a signaling accelerated loss of osteoblast differentiation capacity. miR-29a reduced HDAC4 signaling and attenuated the glucocorticoid-mediated β-catenin deacetylation and ubiquitination and restored nuclear β-catenin levels. Glucocorticoid-induced loss of miR-29a signaling occurred through transcriptional and translational regulation. Interruption of HDAC4 signaling attenuated the glucocorticoid-induced hypoacetylation of histone H3 at lysine 9 (H3K9Ac) and restored the enrichment of H3K9Ac in miR-29a proximal promoter region and miR-29a transcription in cell cultures. Taken together, excess glucocorticoid-induced loss of miR-29a signaling accelerates β-catenin deacetylation and ubiquitination that impairs osteogenic activities of osteoblast cultures. mi

  20. Early environments, glucocorticoid receptors, and behavioral epigenetics.

    PubMed

    Champagne, Frances A

    2013-10-01

    In 1985, a brief report published in Behavioral Neuroscience established the link between neonatal handling and concentrations of hippocampal glucocorticoid receptors (GR) in the adult rat, suggesting a neurobiological basis for the attenuated stress reactivity observed in handled versus nonhandled offspring. To celebrate the 30th anniversary of Behavioral Neuroscience, this article explores the research that preceded and followed from this brief but significant publication. Changes in hippocampal GR induced by handling were determined to be the outcome of a cascade of cellular and molecular events involving thyroid hormones, serotonin turnover, and transcription factor binding to the Nr3c1 gene, leading to increased GR mRNA and protein. Though many hypotheses were proposed for the "handling effect," the role of handling-induced changes in maternal care, particularly pup licking/grooming (LG), generated a productive scientific framework for understanding the handling phenomenon. Indeed, LG has since been demonstrated to alter GR levels through the signaling pathways described for handling. Moreover, epigenetic mechanisms have been discovered to play a critical role in the effects of early life experience and particularly in the regulation of Nr3c1. Overall, the research avenues that have evolved from the initial finding of handling-induced changes in GR have broad applications to our understanding of plasticity, resilience, and the transmission of traits across generations. 2013 APA, all rights reserved

  1. Assessment of endocrine disruption potential of essential oils of culinary herbs and spices involving glucocorticoid, androgen and vitamin D receptors.

    PubMed

    Bartoňková, Iveta; Dvořák, Zdeněk

    2018-04-25

    Essential oils (EOs) of culinary herbs and spices are consumed on a daily basis. They are multicomponent mixtures of compounds with already demonstrated biological activities. Taking into account regular dietary intake and the chemical composition of EOs, they may be considered as candidates for endocrine-disrupting entities. Therefore, we examined the effects of 31 EOs of culinary herbs and spices on transcriptional activities of glucocorticoid receptor (GR), androgen receptor (AR) and vitamin D receptor (VDR). Using reporter gene assays in stably transfected cell lines, weak anti-androgen and anti-glucocorticoid activity was observed for EO of vanilla and nutmeg, respectively. Moderate augmentation of calcitriol-dependent VDR activity was caused by EOs of ginger, thyme, coriander and lemongrass. Mixed anti-glucocorticoid and VDR-stimulatory activities were displayed by EOs of turmeric, oregano, dill, caraway, verveine and spearmint. The remaining 19 EOs were inactive against all receptors under investigation. Analyses of GR, AR and VDR target genes by means of RT-PCR confirmed the VDR-stimulatory effects, but could not confirm the anti-glucocorticoid and anti-androgen effects of EOs. In conclusion, although we observed minor effects of several EOs on transcriptional activities of GR, AR and VDR, the toxicological significance of these effects is very low. Hence, 31 EOs of culinary herbs and spices may be considered safe, in terms of endocrine disruption involving receptors GR, AR and VDR.

  2. A putative role for hypothalamic glucocorticoid receptors in hypertension induced by prenatal undernutrition in the rat.

    PubMed

    Pérez, Hernán; Soto-Moyano, Rubén; Ruiz, Samuel; Hernández, Alejandro; Sierralta, Walter; Olivares, Ricardo; Núñez, Héctor; Flores, Osvaldo; Morgan, Carlos; Valladares, Luis; Gatica, Arnaldo; Flores, Francisco J

    2010-10-08

    Prenatal undernutrition induces hypertension later in life, possibly by disturbing the hypothalamo-pituitary-adrenal axis through programming decreased expression of hypothalamic glucocorticoid receptors. We examined the systolic blood pressure, heart rate and plasma corticosterone response to intra-paraventricular dexamethasone, mifepristone and corticosterone in eutrophic and prenatally undernourished young rats. Undernutrition was induced during fetal life by restricting the diet of pregnant mothers to 10 g daily (40% of diet consumed by well-nourished controls). At day 40 of postnatal life (i) intra-paraventricular administration of dexamethasone significantly reduced at least for 24h both the systolic pressure (-11.6%), the heart rate (-20.8%) and the plasma corticosterone (-40.0%) in normal animals, while producing lower effects (-5.5, -8.7, and -22.3%, respectively) on undernourished rats; (ii) intra-paraventricular administration of the antiglucocorticoid receptor ligand mifepristone to normal rats produced opposite effects (8.2, 20.3, and 48.0% increase, respectively) to those induced by dexamethasone, being these not significant in undernourished animals; (iii) intra-paraventricular corticosterone did not exert any significant effect. Results suggest that the low sensitivity of paraventricular neurons to glucocorticoid receptor ligands observed in prenatally undernourished rats could be due to the already reported glucocorticoid receptor expression, found in the hypothalamus of undernourished animals. Copyright (c) 2010 Elsevier Ireland Ltd. All rights reserved.

  3. Dominance rank causally affects personality and glucocorticoid regulation in female rhesus macaques

    PubMed Central

    Kohn, Jordan N.; Snyder-Mackler, Noah; Barreiro, Luis B.; Johnson, Zachary P.; Tung, Jenny; Wilson, Mark E.

    2017-01-01

    Low social status is frequently associated with heightened exposure to social stressors and altered glucocorticoid regulation by the hypothalamic-pituitary-adrenal (HPA) axis. Additionally, personality differences can affect how individuals behave in response to social conditions, and thus may aggravate or protect against the effects of low status on HPA function. Disentangling the relative importance of personality from the effects of the social environment on the HPA axis has been challenging, since social status can predict aspects of behavior, and both can remain stable across the lifespan. To do so here, we studied an animal model of social status and social behavior, the rhesus macaque (Macaca mulatta). We performed two sequential experimental manipulations of dominance rank (i.e., social status) in 45 adult females, allowing us to characterize personality and glucocorticoid regulation (based on sensitivity to the exogenous glucocorticoid dexamethasone) in each individual while she occupied two different dominance ranks. We identified two behavioral characteristics, termed ‘social approachability’ and ‘boldness,’ which were highly social status-dependent. Social approachability and a third dimension, anxiousness, were also associated with cortisol dynamics in low status females, suggesting that behavioral tendencies may sensitize individuals to the effects of low status on HPA axis function. Finally, we found that improvements in dominance rank increased dexamethasone-induced acute cortisol suppression and glucocorticoid negative feedback. Our findings indicate that social status causally affects both behavioral tendencies and glucocorticoid regulation, and that some behavioral tendencies also independently affect cortisol levels, beyond the effects of rank. Together, they highlight the importance of considering personality and social status together when investigating their effects on HPA axis function. PMID:27639059

  4. Dominance rank causally affects personality and glucocorticoid regulation in female rhesus macaques.

    PubMed

    Kohn, Jordan N; Snyder-Mackler, Noah; Barreiro, Luis B; Johnson, Zachary P; Tung, Jenny; Wilson, Mark E

    2016-12-01

    Low social status is frequently associated with heightened exposure to social stressors and altered glucocorticoid regulation by the hypothalamic-pituitary-adrenal (HPA) axis. Additionally, personality differences can affect how individuals behave in response to social conditions, and thus may aggravate or protect against the effects of low status on HPA function. Disentangling the relative importance of personality from the effects of the social environment on the HPA axis has been challenging, since social status can predict aspects of behavior, and both can remain stable across the lifespan. To do so here, we studied an animal model of social status and social behavior, the rhesus macaque (Macaca mulatta). We performed two sequential experimental manipulations of dominance rank (i.e., social status) in 45 adult females, allowing us to characterize personality and glucocorticoid regulation (based on sensitivity to the exogenous glucocorticoid dexamethasone) in each individual while she occupied two different dominance ranks. We identified two behavioral characteristics, termed 'social approachability' and 'boldness,' which were highly social status-dependent. Social approachability and a third dimension, anxiousness, were also associated with cortisol dynamics in low status females, suggesting that behavioral tendencies may sensitize individuals to the effects of low status on HPA axis function. Finally, we found that improvements in dominance rank increased dexamethasone-induced acute cortisol suppression and glucocorticoid negative feedback. Our findings indicate that social status causally affects both behavioral tendencies and glucocorticoid regulation, and that some behavioral tendencies also independently affect cortisol levels, beyond the effects of rank. Together, they highlight the importance of considering personality and social status together when investigating their effects on HPA axis function. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Serum/glucocorticoid-regulated kinase 1 expression in primary human prostate cancers.

    PubMed

    Szmulewitz, Russell Z; Chung, Elizabeth; Al-Ahmadie, Hikmat; Daniel, Silver; Kocherginsky, Masha; Razmaria, Aria; Zagaja, Gregory P; Brendler, Charles B; Stadler, Walter M; Conzen, Suzanne D

    2012-02-01

    Serum/glucocorticoid-regulated kinase 1 (SGK1), a known target of the androgen receptor (AR) and glucocorticoid receptor (GR), is reported to enhance cell survival. This study sought to better define the role of SGK1 and GR in prostate cancer. Immunohistochemistry was performed for AR, GR, and SGK1 on primary prostate cancers (n = 138) and 18 prostate cancers from patients treated with androgen deprivation therapy. Relative staining intensity was compared utilizing a Fisher's exact test. Univariate analyses were performed using log-rank and chi-squared tests to evaluate prostate cancer recurrence with respect to SGK1 expression. SGK1 expression was strong (3+) in 79% of untreated cancers versus 44% in androgen-deprived cancers (P = 0.003). Conversely, GR expression was present in a higher proportion of androgen-deprived versus untreated cancers (78% vs. 38%, P = 0.002). High-grade cancers were nearly twice as likely to have relatively low (0 to 2+) SGK1 staining compared to low-grade cancers (13.8% vs. 26.5%, P = 0.08). Low SGK1 expression in untreated tumors was associated with increased risk of cancer recurrence (adjusted log-rank test P = 0.077), 5-year progression-free survival 47.8% versus 72.6% (P = 0.034). SGK1 expression is high in most untreated prostate cancers and declines with androgen deprivation. However, these data suggest that relatively low expression of SGK1 is associated with higher tumor grade and increased cancer recurrence, and is a potential indicator of aberrant AR signaling in these tumors. GR expression increased with androgen deprivation, potentially providing a mechanism for the maintenance of androgen pathway signaling in these tumors. Further study of the AR/GR/SGK1 network in castration resistance. Copyright © 2011 Wiley Periodicals, Inc.

  6. Development of glucocorticoid receptor regulation in the rat forebrain: Implications for adverse effects of glucocorticoids in preterm infants

    EPA Science Inventory

    Glucocorticoids are the consensus treatment to avoid respiratory distress in preterm infants but there is accumulating evidence that these agents evoke long-term neurobehavioral deficits. Earlier, we showed that the developing rat forebrain is far more sensitive to glucocorticoi...

  7. Glucocorticoid-induced changes in glucocorticoid receptor mRNA and protein expression in the human placenta as a potential factor for altering fetal growth and development.

    PubMed

    Bivol, Svetlana; Owen, Suzzanne J; Rose'Meyer, Roselyn B

    2016-02-05

    Glucocorticoids (GCs) control essential metabolic processes in virtually every cell in the body and play a vital role in the development of fetal tissues and organ systems. The biological actions of GCs are mediated via glucocorticoid receptors (GRs), the cytoplasmic transcription factors that regulate the transcription of genes involved in placental and fetal growth and development. Several experimental studies have demonstrated that fetal exposure to high maternal GC levels early in gestation is associated with adverse fetal outcomes, including low birthweight, intrauterine growth restriction and anatomical and structural abnormalities that may increase the risk of cardiovascular, metabolic and neuroendocrine disorders in adulthood. The response of the fetus to GCs is dependent on gender, with female fetuses becoming hypersensitive to changes in GC levels whereas male fetuses develop GC resistance in the environment of high maternal GCs. In this paper we review GR function and the physiological and pathological effects of GCs on fetal development. We propose that GC-induced changes in the placental structure and function, including alterations in the expression of GR mRNA and protein levels, may play role in inhibiting in utero fetal growth.

  8. MicroRNA-Mediated Down-Regulation of M-CSF Receptor Contributes to Maturation of Mouse Monocyte-Derived Dendritic Cells

    PubMed Central

    Riepsaame, Joey; van Oudenaren, Adri; den Broeder, Berlinda J. H.; van IJcken, Wilfred F. J.; Pothof, Joris; Leenen, Pieter J. M.

    2013-01-01

    Dendritic cell (DC) maturation is a tightly regulated process that requires coordinated and timed developmental cues. Here we investigate whether microRNAs are involved in this process. We identify microRNAs in mouse GM-CSF-generated, monocyte-related DC (GM-DC) that are differentially expressed during both spontaneous and LPS-induced maturation and characterize M-CSF receptor (M-CSFR), encoded by the Csf1r gene, as a key target for microRNA-mediated regulation in the final step toward mature DC. MicroRNA-22, -34a, and -155 are up-regulated in mature MHCIIhi CD86hi DC and mediate Csf1r mRNA and protein down-regulation. Experimental inhibition of Csf1r-targeting microRNAs in vitro results not only in sustained high level M-CSFR protein expression but also in impaired DC maturation upon stimulation by LPS. Accordingly, over-expression of Csf1r in GM-DC inhibits terminal differentiation. Taken together, these results show that developmentally regulated microRNAs control Csf1r expression, supplementing previously identified mechanisms that regulate its transcription and protein surface expression. Furthermore, our data indicate a novel function for Csf1r in mouse monocyte-derived DC, showing that down-regulation of M-CSFR expression is essential for final DC maturation. PMID:24198819

  9. Glucocorticoid Effects on Cerebellar Development in a Chicken Embryo Model: Exploring Changes in PAX6 and Metalloproteinase-9 After Exposure to Dexamethasone.

    PubMed

    Austdal, L P E; Bjørnstad, S; Mathisen, G H; Aden, P K; Mikkola, I; Paulsen, R E; Rakkestad, K E

    2016-12-01

    The developing cerebellum is vulnerable to effects of glucocorticoids and cerebellar dysfunction is associated with neurodevelopmental disorders (e.g. autism). Transcription factor PAX6 and matrix metalloproteinase-9 (MMP-9) are critical for normal cerebellar development and are highly expressed in migrating neurones. Alterations in MMP-9 and PAX6 are associated with altered cerebellar development. In the present study, we characterised the growth rate and development of the cortical layers, and further investigated how the levels of PAX6 and MMP-9, as well as glucocorticoid receptor (GR) and proliferating cell nuclear antigen (PCNA), change in the cerebellum during the foetal period [embryonic day (E)12-21] in chicken, which corresponds to the human perinatal period. Dexamethasone (DEX) was administered in ovo at E13 and E16, aiming to investigate how prenatal exposure to glucocorticoids interferes with normal development. DEX reduced foetal and cerebellar weight at E17 in a dose-dependent manner linked to a reduced level of PCNA and, over time, down-regulation of GR. We report that promoter activity of PAX6 and MMP-9 increased as a result of GR-stimulation in vitro. Prenatal DEX increased the protein level of PAX6 in a transient manner. PAX6 is reduced in mature granule neurones, and this occurred earlier in embryos exposed to DEX than in non-exposed controls. DEX exposure also led to a slow-onset down-regulation of MMP-9. Taken together, these findings indicate that excess prenatal glucocorticoid stimulation disturbs normal development of the cerebellum through mechanisms associated with reduced proliferation and accelerated maturation where PAX6 and MMP-9 play important roles. © 2016 British Society for Neuroendocrinology.

  10. Glucocorticoid receptor in T cells mediates protection from autoimmunity in pregnancy

    PubMed Central

    Engler, Jan Broder; Kursawe, Nina; Solano, María Emilia; Patas, Kostas; Wehrmann, Sabine; Heckmann, Nina; Lühder, Fred; Reichardt, Holger M.; Arck, Petra Clara; Gold, Stefan M.

    2017-01-01

    Pregnancy is one of the strongest inducers of immunological tolerance. Disease activity of many autoimmune diseases including multiple sclerosis (MS) is temporarily suppressed by pregnancy, but little is known about the underlying molecular mechanisms. Here, we investigated the endocrine regulation of conventional and regulatory T cells (Tregs) during reproduction. In vitro, we found the pregnancy hormone progesterone to robustly increase Treg frequencies via promiscuous binding to the glucocorticoid receptor (GR) in T cells. In vivo, T-cell–specific GR deletion in pregnant animals undergoing experimental autoimmune encephalomyelitis (EAE), the animal model of MS, resulted in a reduced Treg increase and a selective loss of pregnancy-induced protection, whereas reproductive success was unaffected. Our data imply that steroid hormones can shift the immunological balance in favor of Tregs via differential engagement of the GR in T cells. This newly defined mechanism confers protection from autoimmunity during pregnancy and represents a potential target for future therapy. PMID:28049829

  11. Glucocorticoid receptor-mediated delivery of nano gold-withaferin conjugates for reversal of epithelial-to-mesenchymal transition and tumor regression.

    PubMed

    Agarwalla, Pritha; Mukherjee, Sudip; Sreedhar, Bojja; Banerjee, Rajkumar

    2016-10-01

    To explore the potential of glucocorticoid receptor-targeted nano-gold formulation as antitumor drug sensitizing agent. Simultaneous conjugation of gold nanoparticle with thiol-modified dexamethasone, a synthetic glucocorticoid and anticancer drug withaferin A afforded stable gold nanoparticle-modifed dexamethasone-withaferin A nanoconjugate. This metallic nanoparticle formulation showed glucocorticoid receptor-dependent cancer cell selective cytotoxicity, inhibited growth of aggressive mouse melanoma tumor, reduced mice mortality, while reversing epithelial-to-mesenchymal transition in tumor cells. Same treatment also leads to near-complete downregulation of ABCG2 drug transporter in tumor-associated cells thus attributing it to its drug sensitizing ability. The presently synthesized nanoconjugate holds a great promise to sensitize cancer cells to chemotherapeutics and induce epithelial-to-mesenchymal transition reversal in tumor cells preventing metastasis.

  12. Berberine Inhibits Proliferation and Down-Regulates Epidermal Growth Factor Receptor through Activation of Cbl in Colon Tumor Cells

    PubMed Central

    Wang, Lihong; Cao, Hailong; Lu, Ning; Liu, Liping; Wang, Bangmao; Hu, Tianhui; Israel, Dawn A.; Peek, Richard M.; Polk, D. Brent; Yan, Fang

    2013-01-01

    Berberine, an isoquinoline alkaloid, is an active component of Ranunculaceae and Papaveraceae plant families. Berberine has been found to suppress growth of several tumor cell lines in vitro through the cell-type-dependent mechanism. Expression and activation of epidermal growth factor receptor (EGFR) is increased in colonic precancerous lesions and tumours, thus EGFR is considered a tumour promoter. The aim of this study was to investigate the effects and mechanisms of berberine on regulation of EGFR activity and proliferation in colonic tumor cell lines and in vivo. We reported that berberine significantly inhibited basal level and EGF-stimulated EGFR activation and proliferation in the immorto Min mouse colonic epithelial (IMCE) cells carrying the APC min mutation and human colonic carcinoma cell line, HT-29 cells. Berberine acted to inhibit proliferation through inducing G1/S and G2/M cell cycle arrest, which correlated with regulation of the checkpoint protein expression. In this study, we also showed that berberine stimulated ubiquitin ligase Cbl activation and Cbl's interaction with EGFR, and EGFR ubiquitinylation and down-regulation in these two cell lines in the presence or absence of EGF treatment. Knock-down Cbl expression blocked the effects of berberine on down-regulation of EGFR and inhibition of proliferation. Furthermore, berberine suppressed tumor growth in the HT-29 cell xenograft model. Cell proliferation and EGFR expression level was decreased by berberine treatment in this xenograft model and in colon epithelial cells of APC min/+ mice. Taken together, these data indicate that berberine enhances Cbl activity, resulting in down-regulation of EGFR expression and inhibition of proliferation in colon tumor cells. PMID:23457600

  13. Treadmill Slope Modulates Inflammation, Fiber Type Composition, Androgen, and Glucocorticoid Receptors in the Skeletal Muscle of Overtrained Mice

    PubMed Central

    da Rocha, Alisson L.; Pereira, Bruno C.; Teixeira, Giovana R.; Pinto, Ana P.; Frantz, Fabiani G.; Elias, Lucila L. K.; Lira, Fábio S.; Pauli, José R.; Cintra, Dennys E.; Ropelle, Eduardo R.; de Moura, Leandro P.; Mekary, Rania A.; de Freitas, Ellen C.; da Silva, Adelino S. R.

    2017-01-01

    Overtraining (OT) may be defined as an imbalance between excessive training and adequate recovery period. Recently, a downhill running-based overtraining (OTR/down) protocol induced the nonfunctional overreaching state, which is defined as a performance decrement that may be associated with psychological and hormonal disruptions and promoted intramuscular and systemic inflammation. To discriminate the eccentric contraction effects on interleukin 1beta (IL-1β), IL-6, IL-10, IL-15, and SOCS-3, we compared the release of these cytokines in OTR/down with other two OT protocols with the same external load (i.e., the product between training intensity and volume), but performed in uphill (OTR/up) and without inclination (OTR). Also, we evaluated the effects of these OT models on the muscle morphology and fiber type composition, serum levels of fatigue markers and corticosterone, as well as androgen receptor (AR) and glucocorticoid receptor (GR) expressions. For extensor digitorum longus (EDL), OTR/down and OTR groups increased the cytokines and exhibited micro-injuries with polymorphonuclear infiltration. While OTR/down group increased the cytokines in soleus muscle, OTR/up group only increased IL-6. All OT groups presented micro-injuries with polymorphonuclear infiltration. In serum, while OTR/down and OTR/up protocols increased IL-1β, IL-6, and tumor necrosis factor alpha, OTR group increased IL-1β, IL-6, IL-15, and corticosterone. The type II fibers in EDL and soleus, total and phosphorylated AR levels in soleus, and total GR levels in EDL and soleus were differentially modulated by the OT protocols. In summary, the proinflammatory cytokines were more sensitive for OTR/down than for OTR/up and OTR. Also, the specific treadmill inclination of each OT model influenced most of the other evaluated parameters. PMID:29163473

  14. Effects of Social Isolation on Glucocorticoid Regulation in Social Mammals

    PubMed Central

    Hawkley, Louise C.; Cole, Steve W.; Capitanio, John P.; Norman, Greg J.; Cacioppo, John T.

    2012-01-01

    The regulation and function of the hypothalamic-pituitary-adrenocortical (HPA) axis and glucocorticoids have been well conserved across vertebrate species. Glucocorticoids influence a wide range of physiological functions that include glucose regulation, metabolism, inflammatory control, as well as cardiovascular, reproductive, and neuronal effects. Some of these are relatively quick-acting non-genomic effects, but most are slower-acting genomic effects. Thus, any stimulus that affects HPA function has the potential to exert wide-ranging short-term and long-term effects on much of vertebrate physiology. Here, we review the effects of social isolation on the functioning of the HPA axis in social species, and on glucocorticoid physiology in social mammals in particular. Evidence indicates that objective and perceived social isolation alter HPA regulation, although the nature and direction of the HPA response differs among species and across age. The inconsistencies in the direction and nature of HPA effects have implications for drawing cross-species conclusions about the effects of social isolation, and are particularly problematic for understanding HPA-related physiological processes in humans. The animal and human data are incommensurate because, for example, animal studies of objective isolation have typically not been modeled on, or for comparability with, the subjective experience of isolation in humans. An animal model of human isolation must be taken more seriously if we want to advance our understanding of the mechanisms for the effects of objective and perceived isolation in humans. PMID:22663934

  15. Glucocorticoid receptor-PPARα axis in fetal mouse liver prepares neonates for milk lipid catabolism

    PubMed Central

    Rando, Gianpaolo; Tan, Chek Kun; Khaled, Nourhène; Montagner, Alexandra; Leuenberger, Nicolas; Bertrand-Michel, Justine; Paramalingam, Eeswari; Guillou, Hervé; Wahli, Walter

    2016-01-01

    In mammals, hepatic lipid catabolism is essential for the newborns to efficiently use milk fat as an energy source. However, it is unclear how this critical trait is acquired and regulated. We demonstrate that under the control of PPARα, the genes required for lipid catabolism are transcribed before birth so that the neonatal liver has a prompt capacity to extract energy from milk upon suckling. The mechanism involves a fetal glucocorticoid receptor (GR)-PPARα axis in which GR directly regulates the transcriptional activation of PPARα by binding to its promoter. Certain PPARα target genes such as Fgf21 remain repressed in the fetal liver and become PPARα responsive after birth following an epigenetic switch triggered by β-hydroxybutyrate-mediated inhibition of HDAC3. This study identifies an endocrine developmental axis in which fetal GR primes the activity of PPARα in anticipation of the sudden shifts in postnatal nutrient source and metabolic demands. DOI: http://dx.doi.org/10.7554/eLife.11853.001 PMID:27367842

  16. Checks and balances: The glucocorticoid receptor and NFĸB in good times and bad.

    PubMed

    Bekhbat, Mandakh; Rowson, Sydney A; Neigh, Gretchen N

    2017-07-01

    Mutual regulation and balance between the endocrine and immune systems facilitate an organism's stress response and are impaired following chronic stress or prolonged immune activation. Concurrent alterations in stress physiology and immunity are increasingly recognized as contributing factors to several stress-linked neuropsychiatric disorders including depression, anxiety, and post-traumatic stress disorder. Accumulating evidence suggests that impaired balance and crosstalk between the glucocorticoid receptor (GR) and nuclear factor kappa-light-chain-enhancer of activated B cells (NFκB) - effectors of the stress and immune axes, respectively - may play a key role in mediating the harmful effects of chronic stress on mood and behavior. Here, we first review the molecular mechanisms of GR and NFκB interactions in health, then describe potential shifts in the GR-NFκB dynamics in chronic stress conditions within the context of brain circuitry relevant to neuropsychiatric diseases. Furthermore, we discuss developmental influences and sex differences in the regulation of these two transcription factors. Copyright © 2017 Elsevier Inc. All rights reserved.

  17. Stabilization of glucocorticoid receptors in isolated rat hepatocytes by radioprotectants

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Karle, J.M.; Ridder, W.E.; Wright, N.

    1986-05-01

    Previous work has shown that glucocorticoid receptors in rat liver homogenate can be stabilized by the addition of MoO/sub 4/ plus the sulfhydryl-containing compounds dithiothreitol and WR 1065. The latter is the dephosphorylated, principal metabolite of the radioprotectant WR 2721 (or S-2-(3-aminopropylamino)ethanesphosphorothioic acid). The current work results from applying this knowledge to intact rat hepatocytes. Cells were isolated by collagenase perfusion and incubated in supplemented minimum essential medium at 37/sup 0/C with various concentrations of WR 2721, WR 1065, or vehicle. Samples of these cell suspensions were analyzed at various times for steroid binding capacity by incubating homogenates (27,000 xmore » g supernates) with 50 nM /sup 3/H-triamcinolone acetonide in the presence or absence of excess unlabelled dexamethasone. Concentrations of 10 mM WR 2721 provided marked preservation of the binding capacity (>85% of the initial value at 5 hours) compared to control at <20% by 2 hours. WR 2721 at 1 mM preserved >60% of the binding capacity. WR 1065 at 10 mM provided no such protection. This is consistent with the observation that WR 1065 does not pass cell membranes. The authors propose that supplying reducing equivalents to intracellular components such as the glucocorticoid receptor may be one mechanism of the radioprotection afforded by WR 2721.« less

  18. Apigenin suppresses migration and invasion of transformed cells through down-regulation of C-X-C chemokine receptor 4 expression

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Wang, Lei; Kuang, Lisha; Hitron, John Andrew

    Environmental exposure to arsenic is known to cause various cancers. There are some potential relationships between cell malignant transformation and C-X-C chemokine receptor type 4 (CXCR4) expressions. Metastasis, one of the major characteristics of malignantly transformed cells, contributes to the high mortality of cells. CXCR4 and its natural chemokine ligand C-X-C motif ligand 12 (CXCL12) play a critical role in metastasis. Therefore, identification of nutritional factors which are able to inhibit CXCR4 is important for protection from environmental arsenic-induced carcinogenesis and for abolishing metastasis of malignantly transformed cells. The present study demonstrates that apigenin (4′,5,7-trihydroxyflavone), a natural dietary flavonoid, suppressedmore » CXCR4 expression in arsenic-transformed Beas-2B cells (B-AsT) and several other types of transformed/cancer cells in a dose- and time-dependent manner. Neither proteasome nor lysosome inhibitor had any effect in reducing the apigenin-induced down-regulation of CXCR4, indicating that apigenin-induced down-regulation of CXCR4 is not due to proteolytic degradation. The down-regulation of CXCR4 is mainly due to the inhibition of nuclear factor κB (NF-κB) transcriptional activity. Apigenin also abolished migration and invasion of transformed cells induced by CXCL12. In a xenograft mouse model, apigenin down-regulated CXCR4 expression and suppressed tumor growth. Taken together, our results show that apigenin is a novel inhibitor of CXCR4 expression. This dietary flavonoid has the potential to suppress migration and invasion of transformed cells and prevent environmental arsenic-induced carcinogenesis. - Highlights: • Apigenin has a potential in preventing environmental arsenic induced carcinogenesis. • Apigenin suppresses CXCR4 in malignant transformed cells in vitro and in vivo. • The down-regulation of CXCR4 is mainly due to inhibition of NF-κB activity.« less

  19. Glucocorticoid actions on L6 muscle cells in culture

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Max, S.R.; Konagaya, M.; Konagaya, Y.

    1986-05-01

    Glucocorticoids exert striking catabolic effects on skeletal muscle. The mechanism of these effects remains poorly understood. They employed L6 muscle cells in culture to ascertain whether intracellular glucocorticoid receptors are involved. Studies in vitro permit exploration of glucocorticoid effects in the absence of other hormonal influences. L6 myoblasts were induced to form differentiated myotubes by growth in 1% serum. L6 myotubes were found to possess a high-affinity, limited capacity intracellular glucocorticoid receptor (apparent K/sub D/ = 5 x 10/sup -10/ M; B/sub max/ = 711 pmols/g protein) with ligand specificity similar to that of glucocorticoid receptors from classical glucocorticoid targetmore » tissues. Further, (/sup 3/H) triamcinolone acetonide specific binding to L6 cell homogenates was blocked by a glucocorticoid antagonist, RU38486 (11..beta..-(4-dimethyl-aminophenyl)-17..beta..-hydroxy-17..cap alpha..-(prop-l-ynyl)-estra-4,9-dien-3-one). Dexamethasone (10/sup -5/M) caused a 10-fold increase in the activity of gluatmine synthetase in L6 myotubes; this increase was prevented by RU38486. Similarly, dexamethasone (10/sup -5/M) caused a 20% decrease in (/sup 12/C) leucine incorporation into protein. This effect also was blocked by RU38486. Thus, induction of glutamine synthetase and diminution of protein synthesis by dexamethasone require intracellular glucocorticoid receptors. L6 cells should prove particularly valuable for further studies of glucocorticoid actions on skeletal muscle.« less

  20. Human microRNA-1245 down-regulates the NKG2D receptor in natural killer cells and impairs NKG2D-mediated functions

    PubMed Central

    Espinoza, J. Luis; Takami, Akiyoshi; Yoshioka, Katsuji; Nakata, Katsuya; Sato, Tokiharu; Kasahara, Yoshihito; Nakao, Shinji

    2012-01-01

    Background NKG2D is an activating receptor expressed by natural killer and T cells, which have crucial functions in tumor and microbial immunosurveillance. Several cytokines have been identified as modulators of NKG2D receptor expression. However, little is known about NKG2D gene regulation. In this study, we found that microRNA 1245 attenuated the expression of NKG2D in natural killer cells. Design and Methods We investigated the potential interactions between the 3′-untranslated region of the NKG2D gene and microRNA as well as their functional roles in the regulation of NKG2D expression and cytotoxicity in natural killer cells. Results Transforming growth factor-β1, a major negative regulator of NKG2D expression, post-transcriptionally up-regulated mature microRNA-1245 expression, thus down-regulating NKG2D expression and impairing NKG2D-mediated immune responses in natural killer cells. Conversely, microRNA-1245 down-regulation significantly increased the expression of NKG2D expression in natural killer cells, resulting in more efficient NKG2D-mediated cytotoxicity. Conclusions These results reveal a novel NKG2D regulatory pathway mediated by microRNA-1245, which may represent one of the mechanisms used by transforming growth factor-β1 to attenuate NKG2D expression in natural killer cells. PMID:22491735

  1. Childhood Adversity and Epigenetic Regulation of Glucocorticoid Signaling Genes: Associations in Children and Adults

    PubMed Central

    Tyrka, Audrey R.; Ridout, Kathryn K.; Parade, Stephanie H.

    2017-01-01

    Early childhood experiences have lasting effects on development, including the risk for psychiatric disorders. Research examining the biologic underpinnings of these associations has revealed the impact of childhood maltreatment on the physiologic stress response and activity of the hypothalamic pituitary adrenal (HPA) axis. A growing body of literature supports the hypothesis that environmental exposures mediate their biological effects via epigenetic mechanisms. Methylation, which is thought to be the most stable form of epigenetic change, is a likely mechanism by which early life exposures has lasting effects. In this review, we present recent evidence related to epigenetic regulation of genes involved in HPA axis regulation, namely the glucocorticoid receptor gene (NR3C1) and FK506 binding protein 51 (FKBP5), after childhood adversity and associations with risk for psychiatric disorders. Implications for the development of interventions and future research are discussed. PMID:27691985

  2. Mechanisms for the Evolution of a Derived Function in the Ancestral Glucocorticoid Receptor

    PubMed Central

    Carroll, Sean Michael; Ortlund, Eric A.; Thornton, Joseph W.

    2011-01-01

    Understanding the genetic, structural, and biophysical mechanisms that caused protein functions to evolve is a central goal of molecular evolutionary studies. Ancestral sequence reconstruction (ASR) offers an experimental approach to these questions. Here we use ASR to shed light on the earliest functions and evolution of the glucocorticoid receptor (GR), a steroid-activated transcription factor that plays a key role in the regulation of vertebrate physiology. Prior work showed that GR and its paralog, the mineralocorticoid receptor (MR), duplicated from a common ancestor roughly 450 million years ago; the ancestral functions were largely conserved in the MR lineage, but the functions of GRs—reduced sensitivity to all hormones and increased selectivity for glucocorticoids—are derived. Although the mechanisms for the evolution of glucocorticoid specificity have been identified, how reduced sensitivity evolved has not yet been studied. Here we report on the reconstruction of the deepest ancestor in the GR lineage (AncGR1) and demonstrate that GR's reduced sensitivity evolved before the acquisition of restricted hormone specificity, shortly after the GR–MR split. Using site-directed mutagenesis, X-ray crystallography, and computational analyses of protein stability to recapitulate and determine the effects of historical mutations, we show that AncGR1's reduced ligand sensitivity evolved primarily due to three key substitutions. Two large-effect mutations weakened hydrogen bonds and van der Waals interactions within the ancestral protein, reducing its stability. The degenerative effect of these two mutations is extremely strong, but a third permissive substitution, which has no apparent effect on function in the ancestral background and is likely to have occurred first, buffered the effects of the destabilizing mutations. Taken together, our results highlight the potentially creative role of substitutions that partially degrade protein structure and function and

  3. Fulvestrant (ICI 182,780) down-regulates androgen receptor expression and diminishes androgenic responses in LNCaP human prostate cancer cells.

    PubMed

    Bhattacharyya, Rumi S; Krishnan, Aruna V; Swami, Srilatha; Feldman, David

    2006-06-01

    The androgen receptor (AR) plays a key role in the development and progression of prostate cancer. Targeting the AR for down-regulation would be a useful strategy for treating prostate cancer, especially hormone-refractory or androgen-independent prostate cancer. In the present study, we showed that the antiestrogen fulvestrant [ICI 182,780 (ICI)] effectively suppressed AR expression in several human prostate cancer cells, including androgen-independent cells. In LNCaP cells, ICI (10 micromol/L) treatment decreased AR mRNA expression by 43% after 24 hours and AR protein expression by approximately 50% after 48 hours. We further examined the mechanism of AR down-regulation by ICI in LNCaP cells. ICI did not bind to the T877A-mutant AR present in the LNCaP cells nor did it promote proteasomal degradation of the AR. ICI did not affect AR mRNA or protein half-life. However, ICI decreased the activity of an AR promoter-luciferase reporter plasmid transfected into LNCaP cells, suggesting a direct repression of AR gene transcription. As a result of AR down-regulation by ICI, androgen induction of prostate-specific antigen mRNA and protein expression were substantially attenuated. Importantly, LNCaP cell proliferation was significantly inhibited by ICI treatment. Following 6 days of ICI treatment, a 70% growth inhibition was seen in androgen-stimulated LNCaP cells. These data show that the antiestrogen ICI is a potent AR down-regulator that causes significant inhibition of prostate cancer cell growth. Our study suggests that AR down-regulation by ICI would be an effective strategy for the treatment of all prostate cancer, especially AR-dependent androgen-independent prostate cancer.

  4. Mono-(2-ethylhexyl) phthalate (MEHP) regulates glucocorticoid metabolism through 11{beta}-hydroxysteroid dehydrogenase 2 in murine gonadotrope cells

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Hong, Dun; Department of Orthopedics, Taizhou Hospital, Wenzhou Medical College, Lin Hai, ZJ 317000; Li, Xing-Wang

    2009-11-13

    Di-(2-ethylhexyl) phthalate (DEHP) and its metabolite mono-(2-ethylhexyl) phthalate (MEHP) have been classified as toxicants to the reproductive system at the testis level and DEHP may also impair reproductive axis function at the pituitary levels. However, MEHP is 10-fold more potent than DEHP in toxicity and little is known about the toxicological effect of MEHP on pituitary. In this study, we demonstrated that 11{beta}-hydroxysteroid dehydrogenase type 2 (11{beta}-HSD2), not 11{beta}-HSD1, is strongly expressed in murine gonadotrope L{beta}T2 cells. Interestingly, MEHP inhibited Hsd11b2 mRNA level and 11{beta}-HSD2 enzyme activity in L{beta}T2 cells at as low as 10{sup -7} M. Corticosterone (CORT) atmore » a concentration of 10{sup -6} M significantly inhibited L{beta}T2 cell proliferation after 2-day culture, and 10{sup -6} M RU486, an antagonist of glucocorticoid receptor (GR), reversed this inhibition. However, in the presence of 10{sup -5} or 10{sup -4} M MEHP, the minimal concentration of CORT to inhibit the proliferation of L{beta}T2 cells was lowered to 10{sup -7} M, and 10{sup -6} M RU486 was not able to completely reverse the CORT effect. In conclusion, along with the regulation of GR, 11{beta}-HSD2 may have a key role in glucocorticoid metabolism in L{beta}T2 cells. MEHP may participate in the glucocorticoid metabolism in L{beta}T2 cells through inhibition of 11{beta}-HSD2 enzyme activity. Such perturbation may be of pathological significance as MEHP may interfere with the reproductive system at pituitary level through regulation of glucocorticoid metabolism, especially in neonates with higher risk of phthalates exposure.« less

  5. Hepatic glucocorticoid receptor antagonism is sufficient to reduce elevated hepatic glucose output and improve glucose control in animal models of type 2 diabetes.

    PubMed

    Jacobson, Peer B; von Geldern, Thomas W; Ohman, Lars; Osterland, Marie; Wang, Jiahong; Zinker, Bradley; Wilcox, Denise; Nguyen, Phong T; Mika, Amanda; Fung, Steven; Fey, Thomas; Goos-Nilsson, Annika; Grynfarb, Marlena; Barkhem, Tomas; Marsh, Kennan; Beno, David W A; Nga-Nguyen, Bach; Kym, Philip R; Link, James T; Tu, Noah; Edgerton, Dale S; Cherrington, Alan; Efendic, Suad; Lane, Benjamin C; Opgenorth, Terry J

    2005-07-01

    Glucocorticoids amplify endogenous glucose production in type 2 diabetes by increasing hepatic glucose output. Systemic glucocorticoid blockade lowers glucose levels in type 2 diabetes, but with several adverse consequences. It has been proposed, but never demonstrated, that a liver-selective glucocorticoid receptor antagonist (LSGRA) would be sufficient to reduce hepatic glucose output (HGO) and restore glucose control to type 2 diabetic patients with minimal systemic side effects. A-348441 [(3b,5b,7a,12a)-7,12-dihydroxy-3-{2-[{4-[(11b,17b)-17-hydroxy-3-oxo-17-prop-1-ynylestra-4,9-dien-11-yl] phenyl}(methyl)amino]ethoxy}cholan-24-oic acid] represents the first LSGRA with significant antidiabetic activity. A-348441 antagonizes glucocorticoid-up-regulated hepatic genes, normalizes postprandial glucose in diabetic mice, and demonstrates synergistic effects on blood glucose in these animals when coadministered with an insulin sensitizer. In insulin-resistant Zucker fa/fa rats and fasted conscious normal dogs, A-348441 reduces HGO with no acute effect on peripheral glucose uptake. A-348441 has no effect on the hypothalamic pituitary adrenal axis or on other measured glucocorticoid-induced extrahepatic responses. Overall, A-348441 demonstrates that an LSGRA is sufficient to reduce elevated HGO and normalize blood glucose and may provide a new therapeutic approach for the treatment of type 2 diabetes.

  6. Subchronic Glucocorticoid Receptor Inhibition Rescues Early Episodic Memory and Synaptic Plasticity Deficits in a Mouse Model of Alzheimer's Disease

    PubMed Central

    Lanté, Fabien; Chafai, Magda; Raymond, Elisabeth Fabienne; Salgueiro Pereira, Ana Rita; Mouska, Xavier; Kootar, Scherazad; Barik, Jacques; Bethus, Ingrid; Marie, Hélène

    2015-01-01

    The early phase of Alzheimer's disease (AD) is characterized by hippocampus-dependent memory deficits and impaired synaptic plasticity. Increasing evidence suggests that stress and dysregulation of the hypothalamo-pituitary-adrenal (HPA) axis, marked by the elevated circulating glucocorticoids, are risk factors for AD onset. How these changes contribute to early hippocampal dysfunction remains unclear. Using an elaborated version of the object recognition task, we carefully monitored alterations in key components of episodic memory, the first type of memory altered in AD patients, in early symptomatic Tg2576 AD mice. We also combined biochemical and ex vivo electrophysiological analyses to reveal novel cellular and molecular dysregulations underpinning the onset of the pathology. We show that HPA axis, circadian rhythm, and feedback mechanisms, as well as episodic memory, are compromised in this early symptomatic phase, reminiscent of human AD pathology. The cognitive decline could be rescued by subchronic in vivo treatment with RU486, a glucocorticoid receptor antagonist. These observed phenotypes were paralleled by a specific enhancement of N-Methyl-D-aspartic acid receptor (NMDAR)-dependent LTD in CA1 pyramidal neurons, whereas LTP and metabotropic glutamate receptor-dependent LTD remain unchanged. NMDAR transmission was also enhanced. Finally, we show that, as for the behavioral deficit, RU486 treatment rescues this abnormal synaptic phenotype. These preclinical results define glucocorticoid signaling as a contributing factor to both episodic memory loss and early synaptic failure in this AD mouse model, and suggest that glucocorticoid receptor targeting strategies could be beneficial to delay AD onset. PMID:25622751

  7. Gene expression of growth hormone family and glucocorticoid receptors, osmosensors, and ion transporters in the gill during seawater acclimation of Mozambique tilapia, Oreochromis mossambicus.

    PubMed

    Breves, Jason P; Fox, Bradley K; Pierce, Andrew L; Hirano, Tetsuya; Grau, E Gordon

    2010-08-01

    This study characterized endocrine and ionoregulatory responses accompanying seawater (SW) acclimation in Mozambique tilapia (Oreochromis mossambicus). Changes in plasma hormones and gene expression of hormone receptors, putative osmosensors, and ion transporters in the gill were measured. Transfer of freshwater (FW)-acclimated tilapia to SW resulted in a marked elevation in plasma osmolality and a significant rise in plasma growth hormone (GH) levels at 12 hr and 14 days after transfer. Significant reductions in plasma prolactin (PRL(177) and PRL(188)) levels also occurred in SW-transferred fish; no effect of transfer upon plasma cortisol or insulin-like growth factor I was observed. Gene expression of GH receptor increased strongly 6 hr after transfer, whereas PRL receptor was lower than controls at 12 hr. By contrast, mRNA levels of somatolactin and glucocorticoid receptors were unaffected by SW transfer. Osmotic stress transcription factor 1 mRNA levels rose significantly between 3 and 12 hr, whereas the calcium-sensing receptor was unaffected. Aquaporin-3 gene expression was strongly down-regulated during SW acclimation from 12 hr until the conclusion of the experiment. Na(+)/K(+)/2Cl(-) cotransporter gene expression increased significantly 3 hr after transfer, whereas expression of Na(+)/Cl(-) cotransporter, specific to FW-type chloride cells, declined by 6 hr into SW acclimation. The response of Na(+)/H(+) exchanger was less pronounced, but showed a similar pattern to that of the Na(+)/Cl(-) cotransporter. These results suggest that acquisition of hyposmoregulatory mechanisms in Mozambique tilapia entails the coordinated interaction of systemic hormones with local factors in the gill, including hormone receptors, ion transporters, and osmosensors. (c) 2010 Wiley-Liss, Inc.

  8. Differential Subcellular Localization of the Glucocorticoid Receptor in Distinct Neural Stem and Progenitor Populations of the Mouse Telencephalon In Vivo

    PubMed Central

    Tsiarli, Maria A.; Monaghan, A. Paula; DeFranco, Donald B.

    2013-01-01

    Glucocorticoids are given to pregnant women at risk for premature delivery to promote lung maturation. Despite reports of detrimental effects of glucocorticoids on telencephalic neural stem/progenitor cells (NSPCs), the regional and cellular expression of the glucocorticoid receptor (GR) in various NSPC populations in the intact brain has not been thoroughly assessed. Therefore in this study we performed a detailed analysis of GR protein expression in the developing mouse ventral and dorsal telencephalon in vivo. At embryonic day 11.5 (E11.5), the majority of Pax6-positive radial glial cells (RGCs) and Tbr2-positive intermediate progenitor cells (IPCs) expressed nuclear GR, while a small number of RGCs on the apical ventricular zone (aVZ), expressed cytoplasmic GR. However, on E13.5, the latter population of RGCs increased in size, whereas abventricular NSPCs and especially neurons of the cortical plate, expressed nuclear GR. In IPCs, GR was always nuclear. A similar expression profile was observed throughout the ventral telencephalon, hippocampus and olfactory bulb, with NSPCs of the aVZ primarily expressing cytoplasmic GR, while abventricular NSPCs and mature cells primarily expressed nuclear GR. Close to birth, nuclear GR accumulated within specific cortical areas such as layer V, the subplate and CA1 area of the hippocampus. In summary, our data show that GR protein is present in early NSPCs of the dorsal and ventral telencephalon at E11.5 and primarily occupies the nucleus. Moreover, our study suggests that the subcellular localization of the receptor may be subjected to region and neurodevelopmental stage-specific regulation. PMID:23751362

  9. Prenatal arsenic exposure alters the programming of the glucocorticoid signaling system during embryonic development

    PubMed Central

    Caldwell, Katharine E.; Labrecque, Matthew T.; Solomon, Benjamin R.; Ali, Abdulmehdi; Allan, Andrea M.

    2015-01-01

    The glucocorticoid system, which plays a critical role in a host of cellular functions including mood disorders and learning and memory, has been reported to be disrupted by arsenic. In previous work we have developed and characterized a prenatal moderate arsenic exposure (50 ppb) model and identified several deficits in learning and memory and mood disorders, as well as alterations within the glucocorticoid receptor signaling system in the adolescent mouse. In these present studies we assessed the effects of arsenic on the glucocorticoid receptor (GR) pathway in both the placenta and the fetal brain in response at two critical periods, embryonic days 14 and 18. The focus of these studies was on the 11β-hydroxysteroid dehydrogenase enzymes (11β-HSD1 and 11β-HSD2) which play a key role in glucorticoid synthesis, as well as the expression and set point of the GR negative feedback regulation. Negative feedback regulation is established early in development. At E14 we found arsenic exposure significantly decreased expression of both protein and message in brain of GR and the 11β-HSD1, while 11β-HSD2 enzyme protein levels were increased but mRNA levels were decreased in the brain. These changes in brain protein continued into the E18 time point, but mRNA levels were no longer significantly altered. Placental HSD11B2 mRNA was not altered by arsenic treatment but protein levels were elevated at E14. GR placental protein levels were decreased at E18 in the arsenic exposed condition. This suggests that arsenic exposure may alter GR expression levels as a consequence of a prolonged developmental imbalance between 11β-HSD1 and 11β-HSD2 protein expression despite decreased 11HSDB2 mRNA. The suppression of GR and the failure to turn down 11β-HSD2 protein expression during fetal development may lead to an altered set point for GR signaling throughout adulthood. To our knowledge, these studies are the first to demonstrate that gestational exposure to moderate levels of

  10. Glucocorticoid receptor represses brain-derived neurotrophic factor expression in neuron-like cells.

    PubMed

    Chen, Hui; Lombès, Marc; Le Menuet, Damien

    2017-04-12

    Brain-derived neurotrophic factor (BDNF) is involved in many functions such as neuronal growth, survival, synaptic plasticity and memorization. Altered expression levels are associated with many pathological situations such as depression, epilepsy, Alzheimer's, Huntington's and Parkinson's diseases. Glucocorticoid receptor (GR) is also crucial for neuron functions, via binding of glucocorticoid hormones (GCs). GR actions largely overlap those of BDNF. It has been proposed that GR could be a regulator of BDNF expression, however the molecular mechanisms involved have not been clearly defined yet. Herein, we analyzed the effect of a GC agonist dexamethasone (DEX) on BDNF expression in mouse neuronal primary cultures and in the newly characterized, mouse hippocampal BZ cell line established by targeted oncogenesis. Mouse Bdnf gene exhibits a complex genomic structure with 8 untranslated exons (I to VIII) splicing onto one common and unique coding exon IX. We found that DEX significantly downregulated total BDNF mRNA expression by around 30%. Expression of the highly expressed exon IV and VI containing transcripts was also reduced by DEX. The GR antagonist RU486 abolished this effect, which is consistent with specific GR-mediated action. Transient transfection assays allowed us to define a short 275 bp region within exon IV promoter responsible for GR-mediated Bdnf repression. Chromatin immunoprecipitation experiments demonstrated GR recruitment onto this fragment, through unidentified transcription factor tethering. Altogether, GR downregulates Bdnf expression through direct binding to Bdnf regulatory sequences. These findings bring new insights into the crosstalk between GR and BDNF signaling pathways both playing a major role in physiology and pathology of the central nervous system.

  11. Identification of cysteine-644 as the covalent site of attachment of dexamethasone 21-mesylate to murine glucocorticoid receptors in WEHI-7 cells

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Smith, L.I.; Bodwell, J.E.; Mendel, D.B.

    1988-05-17

    Dexamethasone 21-mesylate is a highly specific synthetic glucocorticoid derivative that binds covalently to glucocorticoid receptors via sulfhydryl groups. The authors have identified the amino acid that reacts with the dexamethasone 21-mesylate by using enzymatic digestion and microsequencing for radiolabel. Nonactivated glucocorticoid receptors obtained from labeling intact WEHI-7 mouse thymoma cells with (/sup 3/H)dexamethasone 21-mesylate were immunopurified and analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Trypsin digestion followed by reversed-phase high-performance liquid chromatography (reversed-phase HPLC) produced a single (/sup 3/H)dexamethasone 21-mesylate labeled peptide. Automated Edman degradation of this peptide revealed that the (/sup 3/H)dexamethasone 21-mesylate was located at position 5 frommore » the amino terminus. Dual-isotope labeling studies with (/sup 3/H)dexamethasone 21-mesylate and (/sup 35/S)methionine demonstrated that this peptide contained methionine. Staphylococcus aureus V8 protease digestion of (/sup 3/H)dexamethasone 21-mesylate labeled steroid-binding subunits generated a different radiolabeled peptide containing label at position 7 from the amino terminus. On the basis of the published amino acid sequence of the murine glucocorticoid receptor, their data clearly identify cysteine-644 as the single residue in the steroid-binding domain that covalently binds dexamethasone 21-mesylate. They have confirmed this finding by demonstrating that a synthetic peptide representing the amino acid sequence 640-650 of the murine glucocorticoid receptor behaves in an identical manner on reversed-phase HPLC as the trypsin-generated peptide from intact cells.« less

  12. Glucocorticoids in the prefrontal cortex enhance memory consolidation and impair working memory by a common neural mechanism

    PubMed Central

    Barsegyan, Areg; Mackenzie, Scott M.; Kurose, Brian D.; McGaugh, James L.; Roozendaal, Benno

    2010-01-01

    It is well established that acute administration of adrenocortical hormones enhances the consolidation of memories of emotional experiences and, concurrently, impairs working memory. These different glucocorticoid effects on these two memory functions have generally been considered to be independently regulated processes. Here we report that a glucocorticoid receptor agonist administered into the medial prefrontal cortex (mPFC) of male Sprague-Dawley rats both enhances memory consolidation and impairs working memory. Both memory effects are mediated by activation of a membrane-bound steroid receptor and depend on noradrenergic activity within the mPFC to increase levels of cAMP-dependent protein kinase. These findings provide direct evidence that glucocorticoid effects on both memory consolidation and working memory share a common neural influence within the mPFC. PMID:20810923

  13. Possible involvement of the glucocorticoid receptor (NR3C1) and selected NR3C1 gene variants in regulation of human testicular function.

    PubMed

    Nordkap, L; Almstrup, K; Nielsen, J E; Bang, A K; Priskorn, L; Krause, M; Holmboe, S A; Winge, S B; Egeberg Palme, D L; Mørup, N; Petersen, J H; Juul, A; Skakkebaek, N E; Rajpert-De Meyts, E; Jørgensen, N

    2017-11-01

    Perceived stress has been associated with decreased semen quality but the mechanisms have not been elucidated. It is not known whether cortisol, the major stress hormone in humans, can act directly via receptors in the testis, and whether variants in the gene encoding the glucocorticoid receptor (NR3C1) can possibly modulate the effect. To address these questions, we investigated the expression of the glucocorticoid receptor in human testicular tissue, including adult and fetal samples (n = 20) by immunohistochemical staining, and in silico analysis of publicly available datasets. In the adult testis NR3C1 protein was detected in peritubular cells, a subset of Leydig cells, Sertoli cells (weak), and spermatogonia, but not in spermatids. The NR3C1 expression pattern in fetal testis samples differed by a notably stronger reaction in Sertoli cells, lack of staining in gonocytes but the presence in a subset of pro-spermatogonia, and the almost absent reaction in nascent peritubular cells. In parallel, we explored the association between adult testicular function and three single nucleotide NR3C1 polymorphisms (BcII [rs41423247], 9β [rs6198], and Tth111I [rs10052957]) affecting glucocorticoid sensitivity. Testicular function was determined by semen analysis and reproductive hormone profiling in 893 men from the general population. The NR3C1 SNP BclI was associated with semen quality in an over-dominant manner with heterozygotes having better semen parameters compared to both homozygote constellations, and with sperm motility showing the strongest association. This association was supported by a higher inhibin B and inhibin B/FSH ratio, as well as a lower FSH in BclI heterozygotes. The SNPs 9β and Tth111I were not associated with semen parameters. Although the clinical impact of the findings is limited, the results substantiate a suggested link between stress and testicular function. Hence this investigation should be regarded as a discovery study generating

  14. Glucocorticoid receptor gene expression and promoter CpG modifications throughout the human brain.

    PubMed

    Cao-Lei, Lei; Suwansirikul, Songkiet; Jutavijittum, Prapan; Mériaux, Sophie B; Turner, Jonathan D; Muller, Claude P

    2013-11-01

    Glucocorticoids and the glucocorticoid (GR) and mineralocorticoid (MR) receptors have been implicated in many processes, particularly in negative feedback regulation of the hypothalamic-pituitary-adrenal axis. Epigenetically programmed GR alternative promoter usage underlies transcriptional control of GR levels, generation of GR 3' splice variants, and the overall GC response in the brain. No detailed analysis of GR first exons or GR transcript variants throughout the human brain has been reported. Therefore we investigated post mortem tissues from 28 brain regions of 5 individuals. GR first exons were expressed throughout the healthy human brain with no region-specific usage patterns. First exon levels were highly inter-correlated suggesting that they are co-regulated. GR 3' splice variants (GRα and GR-P) were equally distributed in all regions, and GRβ expression was always low. GR/MR ratios showed significant differences between the 28 tissues with the highest ratio in the pituitary gland. Modification levels of individual CpG dinucleotides, including 5-mC and 5-hmC, in promoters 1D, 1E, 1F, and 1H were low, and diffusely clustered; despite significant heterogeneity between the donors. In agreement with this clustering, sum modification levels rather than individual CpG modifications correlated with GR expression. Two-way ANOVA showed that this sum modification was both promoter and brain region specific, but that there was however no promoter*tissue interaction. The heterogeneity between donors may however hide such an interaction. In both promoters 1F and 1H modification levels correlated with GRα expression suggesting that 5-mC and 5-hmC play an important role in fine tuning GR expression levels throughout the brain. Copyright © 2013 Elsevier Ltd. All rights reserved.

  15. Systems Biology and Birth Defects Prevention: Blockade of the Glucocorticoid Receptor Prevents Arsenic-Induced Birth Defects

    PubMed Central

    Ahir, Bhavesh K.; Sanders, Alison P.; Rager, Julia E.

    2013-01-01

    Background: The biological mechanisms by which environmental metals are associated with birth defects are largely unknown. Systems biology–based approaches may help to identify key pathways that mediate metal-induced birth defects as well as potential targets for prevention. Objectives: First, we applied a novel computational approach to identify a prioritized biological pathway that associates metals with birth defects. Second, in a laboratory setting, we sought to determine whether inhibition of the identified pathway prevents developmental defects. Methods: Seven environmental metals were selected for inclusion in the computational analysis: arsenic, cadmium, chromium, lead, mercury, nickel, and selenium. We used an in silico strategy to predict genes and pathways associated with both metal exposure and developmental defects. The most significant pathway was identified and tested using an in ovo whole chick embryo culture assay. We further evaluated the role of the pathway as a mediator of metal-induced toxicity using the in vitro midbrain micromass culture assay. Results: The glucocorticoid receptor pathway was computationally predicted to be a key mediator of multiple metal-induced birth defects. In the chick embryo model, structural malformations induced by inorganic arsenic (iAs) were prevented when signaling of the glucocorticoid receptor pathway was inhibited. Further, glucocorticoid receptor inhibition demonstrated partial to complete protection from both iAs- and cadmium-induced neurodevelopmental toxicity in vitro. Conclusions: Our findings highlight a novel approach to computationally identify a targeted biological pathway for examining birth defects prevention. PMID:23458687

  16. Associations Between Polymorphisms in the Glucocorticoid-Receptor Gene and Cardiovascular Risk Factors in a Chinese Population

    PubMed Central

    Yan, Yu-Xiang; Dong, Jing; Wu, Li-Juan; Shao, Shuang; Zhang, Jie; Zhang, Ling; Wang, Wei; He, Yan; Liu, You-Qin

    2013-01-01

    Background Glucocorticoid is an important regulator of energy homeostasis. Glucocorticoid receptor (GR) gene polymorphisms that contribute to variability in glucocorticoid sensitivity have been identified. We explored the associations of single-nucleotide polymorphisms (SNPs) of the GR gene with traditional cardiovascular risk factors in the Chinese Han population. Methods We recruited 762 consecutive adults who underwent a regular physical examination at Beijing Xuanwu Hospital. Blood pressure, glucose, lipid levels (total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein [LDL] cholesterol and triglycerides), body mass index (BMI), and waist-to-hip ratio were measured. Fourteen tag SNPs and 5 functional SNPs were selected and genotyped using the high-throughput Sequenom genotyping platform. Differences between genotypes/alleles for each SNP were adjusted for sex and age and tested using a general linear model procedure. Various models of inheritance, including additive, dominant, and recessive, were tested. Results Among the 19 SNPs examined, 5 markers were associated with cardiovascular risk factors. The rs41423247 GG genotype and the rs7701443 AA genotype were associated with higher BMI and systolic blood pressure (P < 0.0004), and the rs17209251 GG genotype was associated with higher systolic blood pressure (P < 0.0004). Lower systolic blood pressure, total cholesterol, and LDL cholesterol were observed among rs10052957 A allele carriers (P < 0.0004), and lower plasma glucose and LDL-cholesterol concentrations were observed among rs2963156 TT carriers (P < 0.0004). Conclusions Polymorphism of the GR gene was associated with cardiovascular risk factors and may contribute to susceptibility to cardiovascular disease. PMID:23892712

  17. Glucocorticoid- and Protein Kinase A–Dependent Transcriptome Regulation in Airway Smooth Muscle

    PubMed Central

    Misior, Anna M.; Deshpande, Deepak A.; Loza, Matthew J.; Pascual, Rodolfo M.; Hipp, Jason D.; Penn, Raymond B.

    2009-01-01

    Glucocorticoids (GCs) and protein kinase A (PKA)–activating agents (β-adrenergic receptor agonists) are mainstream asthma therapies based on their ability to prevent or reverse excessive airway smooth muscle (ASM) constriction. Their abilities to regulate another important feature of asthma—excessive ASM growth—are poorly understood. Recent studies have suggested that GCs render agents of inflammation such as IL-1β and TNF-α mitogenic to ASM, via suppression of (antimitogenic) induced cyclooxygenase-2–dependent PKA activity. To further explore the mechanistic basis of these observations, we assessed the effects of epidermal growth factor and IL-1β stimulation, and the modulatory effects of GC treatment and PKA inhibition, on the ASM transcriptome by microarray analysis. Results demonstrate that ASM stimulated with IL-1β, in a manner that is often cooperative with stimulation with epidermal growth factor, exhibit a profound capacity to function as immunomodulatory cells. Moreover, results implicate an important role for induced autocrine/paracrine factors (many whose regulation was minimally affected by GCs or PKA inhibition) as regulators of both airway inflammation and ASM growth. Induction of numerous chemokines, in conjunction with regulation of proteases and agents of extracellular matrix remodeling, is suggested as an important mechanism promoting upregulated G protein–coupled receptor signaling capable of stimulating ASM growth. Additional functional assays suggest that intracellular PKA plays a critical role in suppressing the promitogenic effects of induced autocrine factors in ASM. Finally, identification and comparison of GC- and PKA-sensitive genes in ASM provide insight into the complementary effects of β-agonist/GC combination therapies, and suggest specific genes as important targets for guiding the development of new generations of GCs and adjunct asthma therapies. PMID:19059887

  18. Endocannabinoid Signaling, Glucocorticoid-Mediated Negative Feedback and Regulation of the HPA Axis

    PubMed Central

    Hill, M. N.; Tasker, J. G.

    2012-01-01

    The hypothalamic-pituitary-adrenal (HPA) axis regulates the outflow of glucocorticoid hormones under basal conditions and in response to stress. Within the last decade, a large body of evidence has mounted indicating that the endocannabinoid system is involved in the central regulation of the stress response; however, the specific role endocannabinoid signalling plays in phases of HPA axis regulation, or the neural sites of action mediating this regulation, was not mapped out until recently. This review aims to collapse the current state of knowledge regarding the role of the endocannabinoid system in the regulation of the HPA axis to put together a working model of how and where endocannabinoids act within the brain to regulate outflow of the HPA axis. Specifically, we discuss the role of the endocannabinoid system in the regulation of the HPA axis under basal conditions, activation in response to acute stress and glucocorticoid-mediated negative feedback. Interestingly, there appears to be some anatomical specificity to the role of the endocannabinoid system in each phase of HPA axis regulation, as well as distinct roles of both anandamide and 2-arachidonoylglycerol in these phases. Ultimately, the current level of information indicates that endocannabinoid signalling acts to suppress HPA axis activity through concerted actions within the prefrontal cortex, amygdala and hypothalamus. PMID:22214537

  19. Novel glucocorticoid receptor agonists in the treatment of asthma.

    PubMed

    Cazzola, Mario; Coppola, Angelo; Rogliani, Paola; Matera, Maria Gabriella

    2015-01-01

    Inhaled corticosteroids are the only drugs that effectively suppress the airway inflammation, but they can induce considerable systemic and adverse effects when they are administered chronically at high doses. Consequently, the pharmaceutical industry is still searching for newer entities with an improved therapeutic index. Herein, the authors review the research in the glucocorticoid field to identify ligands of the glucocorticoid receptor (GR). These ligands preferentially induce transrepression with little or no transactivating activity, in order to have a potent anti-inflammatory action and a low side-effects profile. Several agents have been synthesized, but few have been tested in experimental models of asthma. Furthermore, only three (BI-54903, GW870086X and AZD5423) have entered clinical development, although the development of at least one of them (BI-54903) was discontinued. The reason for the limited success so far obtained is that the model of transactivation versus transrepression is a too simplistic representation of GR activity. It is difficult to uncouple the therapeutic and harmful effects mediated by GR, but some useful information that might change the current perspective is appearing in the literature. The generation of gene expression 'fingerprints' produced by different GR agonists in target and off-target human tissues could be useful in identifying drug candidates with an improved therapeutic ratio.

  20. Gestational dietary betaine supplementation suppresses hepatic expression of lipogenic genes in neonatal piglets through epigenetic and glucocorticoid receptor-dependent mechanisms.

    PubMed

    Cai, Demin; Wang, Junjian; Jia, Yimin; Liu, Haoyu; Yuan, Mengjie; Dong, Haibo; Zhao, Ruqian

    2016-01-01

    Methyl donors play critical roles in nutritional programming through epigenetic regulation of gene expression. Here we fed gestational sows with control or betaine-supplemented diets (3g/kg) throughout the pregnancy to explore the effects of maternal methyl-donor nutrient on neonatal expression of hepatic lipogenic genes. Betaine-exposed piglets demonstrated significantly lower liver triglyceride content associated with down-regulated hepatic expression of lipogenic genes acetyl-CoA carboxylase (ACC), fatty acid synthase (FAS), stearoyl-CoA desaturase (SCD) and sterol regulatory element-binding protein-1c. Moreover, s-adenosyl methionine to s-adenosyl homocysteine ratio was elevated in the liver of betaine-exposed piglets, which was accompanied by DNA hypermethylation on FAS and SCD gene promoters and more enriched repression histone mark H3K27me3 on SCD gene promoter. Furthermore, glucocorticoid receptor (GR) binding to SCD gene promoter was diminished along with reduced serum cortisol and liver GR protein content in betaine-exposed piglets. GR-mediated SCD gene regulation was confirmed in HepG2 cells in vitro. Dexamethasone (Dex) drastically increased the luciferase activity of porcine SCD promoter, while the deletion of GR response element on SCD promoter significantly attenuated Dex-mediated SCD transactivation. In addition, miR-let-7e, miR-1285 and miR-124a, which respectively target porcine SCD, ACC and GR, were significantly up-regulated in the liver of betaine-exposed piglets, being in accordance with decreased protein content of these three genes. Taken together, our results suggest that maternal dietary betaine supplementation during gestation attenuates hepatic lipogenesis in neonatal piglets via epigenetic and GR-mediated mechanisms. Copyright © 2015 Elsevier B.V. All rights reserved.

  1. A Pharmacokinetic/Pharmacodynamic Study of the Glucocorticoid Receptor Antagonist Mifepristone Combined with Enzalutamide in Castrate-Resistant Prostate Cancer

    DTIC Science & Technology

    2017-12-01

    findings contained in this report are those of the author(s) and should not be construed as an official Department of the Army position, policy or...trial for patients with metastatic, castration resistant prostate cancer (CRPC). For patients with metastatic CRPC, there are few established...receptor ( AR ) targeted therapies, prostate cancer adapts. One way it adapts is by upregulating another hormone receptor, the glucocorticoid receptor (GR

  2. Activated glucocorticoid receptor interacts with the INHAT component Set/TAF-Ibeta and releases it from a glucocorticoid-responsive gene promoter, relieving repression: implications for the pathogenesis of glucocorticoid resistance in acute undifferentiated leukemia with Set-Can translocation.

    PubMed

    Ichijo, Takamasa; Chrousos, George P; Kino, Tomoshige

    2008-02-13

    Set/template-activating factor (TAF)-Ibeta, part of the Set-Can oncogene product found in acute undifferentiated leukemia, is a component of the inhibitor of acetyltransferases (INHAT) complex. Set/TAF-Ibeta interacted with the DNA-binding domain of the glucocorticoid receptor (GR) in yeast two-hybrid screening, and repressed GR-induced transcriptional activity of a chromatin-integrated glucocorticoid-responsive and a natural promoter. Set/TAF-Ibeta was co-precipitated with glucocorticoid response elements (GREs) of these promoters in the absence of dexamethasone, while addition of the hormone caused dissociation of Set/TAF-Ibeta from and attraction of the p160-type coactivator GRIP1 to the promoter GREs. Set-Can fusion protein, on the other hand, did not interact with GR, was constitutively co-precipitated with GREs and suppressed GRIP1-induced enhancement of GR transcriptional activity and histone acetylation. Thus, Set/TAF-Ibeta acts as a ligand-activated GR-responsive transcriptional repressor, while Set-Can does not retain physiologic responsiveness to ligand-bound GR, possibly contributing to the poor responsiveness of Set-Can-harboring leukemic cells to glucocorticoids.

  3. Activated Glucocorticoid Receptor Interacts with the INHAT Component Set/TAF-Iβ and Releases it from a Glucocorticoid-responsive Gene Promoter, Relieving Repression: Implications for the Pathogenesis of Glucocorticoid Resistance in Acute Undifferentiated Leukemia with Set-Can Translocation

    PubMed Central

    Ichijo, Takamasa; Chrousos, George P.; Kino, Tomoshige

    2008-01-01

    SUMMARY Set/template-activating factor (TAF)-Iβ, part of the Set-Can oncogene product found in acute undifferentiated leukemia, is a component of the inhibitor of acetyltransferases (INHAT) complex. Set/TAF-Iβ interacted with the DNA-binding domain of the glucocorticoid receptor (GR) in yeast two-hybrid screening, and repressed GR-induced transcriptional activity of a chromatin-integrated glucocorticoid-responsive and a natural promoter. Set/TAF-Iβ was co-precipitated with glucocorticoid response elements (GREs) of these promoters in the absence of dexamethasone, while addition of the hormone caused dissociation of Set/TAF-Iβ from and attraction of the p160-type coactivator GRIP1 to the promoter GREs. Set-Can fusion protein, on the other hand, did not interact with GR, was constitutively co-precipitated with GREs and suppressed GRIP1-induced enhancement of GR transcriptional activity and histone acetylation. Thus, Set/TAF-Iβ acts as a ligand-activated GR-responsive transcriptional repressor, while Set-Can does not retain physiologic responsiveness to ligand-bound GR, possibly contributing to the poor responsiveness of Set-Can-harboring leukemic cells to glucocorticoids. PMID:18096310

  4. Differential subcellular localization of the glucocorticoid receptor in distinct neural stem and progenitor populations of the mouse telencephalon in vivo.

    PubMed

    Tsiarli, Maria A; Paula Monaghan, A; Defranco, Donald B

    2013-07-26

    Glucocorticoids are given to pregnant women at risk for premature delivery to promote lung maturation. Despite reports of detrimental effects of glucocorticoids on telencephalic neural stem/progenitor cells (NSPCs), the regional and cellular expressions of the glucocorticoid receptor (GR) in various NSPC populations in the intact brain have not been thoroughly assessed. Therefore in this study we performed a detailed analysis of GR protein expression in the developing mouse ventral and dorsal telencephalon in vivo. At embryonic day 11.5 (E11.5), the majority of Pax6-positive radial glial cells (RGCs) and Tbr2-positive intermediate progenitor cells (IPCs) expressed nuclear GR, while a small number of RGCs on the apical ventricular zone (aVZ), expressed cytoplasmic GR. However, on E13.5, the latter population of RGCs increased in size, whereas abventricular NSPCs and especially neurons of the cortical plate, expressed nuclear GR. In IPCs, GR was always nuclear. A similar expression profile was observed throughout the ventral telencephalon, hippocampus and olfactory bulb, with NSPCs of the aVZ primarily expressing cytoplasmic GR, while abventricular NSPCs and mature cells primarily expressed nuclear GR. Close to birth, nuclear GR accumulated within specific cortical areas such as layer V, the subplate and CA1 area of the hippocampus. In summary, our data show that GR protein is present in early NSPCs of the dorsal and ventral telencephalon at E11.5 and primarily occupies the nucleus. Moreover, our study suggests that the subcellular localization of the receptor may be subjected to region and neurodevelopmental stage-specific regulation. Copyright © 2013 Elsevier B.V. All rights reserved.

  5. Negative Correlation between the Diffusion Coefficient and Transcriptional Activity of the Glucocorticoid Receptor.

    PubMed

    Mikuni, Shintaro; Yamamoto, Johtaro; Horio, Takashi; Kinjo, Masataka

    2017-08-25

    The glucocorticoid receptor (GR) is a transcription factor, which interacts with DNA and other cofactors to regulate gene transcription. Binding to other partners in the cell nucleus alters the diffusion properties of GR. Raster image correlation spectroscopy (RICS) was applied to quantitatively characterize the diffusion properties of EGFP labeled human GR (EGFP-hGR) and its mutants in the cell nucleus. RICS is an image correlation technique that evaluates the spatial distribution of the diffusion coefficient as a diffusion map. Interestingly, we observed that the averaged diffusion coefficient of EGFP-hGR strongly and negatively correlated with its transcriptional activities in comparison to that of EGFP-hGR wild type and mutants with various transcriptional activities. This result suggests that the decreasing of the diffusion coefficient of hGR was reflected in the high-affinity binding to DNA. Moreover, the hyper-phosphorylation of hGR can enhance the transcriptional activity by reduction of the interaction between the hGR and the nuclear corepressors.

  6. Adipocyte Glucocorticoid Receptor Deficiency Attenuates Aging- and HFD-Induced Obesity and Impairs the Feeding-Fasting Transition.

    PubMed

    Mueller, Kristina M; Hartmann, Kerstin; Kaltenecker, Doris; Vettorazzi, Sabine; Bauer, Mandy; Mauser, Lea; Amann, Sabine; Jall, Sigrid; Fischer, Katrin; Esterbauer, Harald; Müller, Timo D; Tschöp, Matthias H; Magnes, Christoph; Haybaeck, Johannes; Scherer, Thomas; Bordag, Natalie; Tuckermann, Jan P; Moriggl, Richard

    2017-02-01

    Glucocorticoids (GCs) are important regulators of systemic energy metabolism, and aberrant GC action is linked to metabolic dysfunctions. Yet, the extent to which normal and pathophysiological energy metabolism depend on the GC receptor (GR) in adipocytes remains unclear. Here, we demonstrate that adipocyte GR deficiency in mice significantly impacts systemic metabolism in different energetic states. Plasma metabolomics and biochemical analyses revealed a marked global effect of GR deficiency on systemic metabolite abundance and, thus, substrate partitioning in fed and fasted states. This correlated with a decreased lipolytic capacity of GR-deficient adipocytes under postabsorptive and fasting conditions, resulting from impaired signal transduction from β-adrenergic receptors to adenylate cyclase. Upon prolonged fasting, the impaired lipolytic response resulted in abnormal substrate utilization and lean mass wasting. Conversely, GR deficiency attenuated aging-/diet-associated obesity, adipocyte hypertrophy, and liver steatosis. Systemic glucose tolerance was improved in obese GR-deficient mice, which was associated with increased insulin signaling in muscle and adipose tissue. We conclude that the GR in adipocytes exerts central but diverging roles in the regulation of metabolic homeostasis depending on the energetic state. The adipocyte GR is indispensable for the feeding-fasting transition but also promotes adiposity and associated metabolic disorders in fat-fed and aged mice. © 2017 by the American Diabetes Association.

  7. Expression and regulation of glucocorticoid-induced leucine zipper in the developing anterior pituitary gland.

    PubMed

    Ellestad, Laura E; Malkiewicz, Stefanie A; Guthrie, H David; Welch, Glenn R; Porter, Tom E

    2009-02-01

    The expression profile of glucocorticoid-induced leucine zipper (GILZ) in the anterior pituitary during the second half of embryonic development in the chick is consistent with in vivo regulation by circulating corticosteroids. However, nothing else has been reported about the presence of GILZ in the neuroendocrine system. We sought to characterize expression and regulation of GILZ in the chicken embryonic pituitary gland and determine the effect of GILZ overexpression on anterior pituitary hormone levels. Pituitary GILZ mRNA levels increased during embryogenesis to a maximum on the day of hatch, and decreased through the first week after hatch. GILZ expression was rapidly upregulated by corticosterone in embryonic pituitary cells. To determine whether GILZ regulates hormone gene expression in the developing anterior pituitary, we overexpressed GILZ in embryonic pituitary cells and measured mRNA for the major pituitary hormones. Exogenous GILZ increased prolactin mRNA above basal levels, but not as high as that in corticosterone-treated cells, indicating that GILZ may play a small role in lactotroph differentiation. The largest effect we observed was a twofold increase in FSH beta subunit in cells transfected with GILZ but not treated with corticosterone, suggesting that GILZ may positively regulate gonadotroph development in a manner not involving glucocorticoids. In conclusion, this is the first report to characterize avian GILZ and examine its regulation in the developing neuroendocrine system. We have shown that GILZ is upregulated by glucocorticoids in the embryonic pituitary gland and may regulate expression of several pituitary hormones.

  8. Gene-specific mechanisms direct glucocorticoid-receptor-driven repression of inflammatory response genes in macrophages

    PubMed Central

    Sacta, Maria A; Tharmalingam, Bowranigan; Coppo, Maddalena; Rollins, David A; Deochand, Dinesh K; Benjamin, Bradley; Yu, Li; Zhang, Bin; Hu, Xiaoyu; Li, Rong; Chinenov, Yurii

    2018-01-01

    The glucocorticoid receptor (GR) potently represses macrophage-elicited inflammation, however, the underlying mechanisms remain obscure. Our genome-wide analysis in mouse macrophages reveals that pro-inflammatory paused genes, activated via global negative elongation factor (NELF) dissociation and RNA Polymerase (Pol)2 release from early elongation arrest, and non-paused genes, induced by de novo Pol2 recruitment, are equally susceptible to acute glucocorticoid repression. Moreover, in both cases the dominant mechanism involves rapid GR tethering to p65 at NF-kB-binding sites. Yet, specifically at paused genes, GR activation triggers widespread promoter accumulation of NELF, with myeloid cell-specific NELF deletion conferring glucocorticoid resistance. Conversely, at non-paused genes, GR attenuates the recruitment of p300 and histone acetylation, leading to a failure to assemble BRD4 and Mediator at promoters and enhancers, ultimately blocking Pol2 initiation. Thus, GR displays no preference for a specific pro-inflammatory gene class; however, it effects repression by targeting distinct temporal events and components of transcriptional machinery. PMID:29424686

  9. Budesonide suppresses pulmonary antibacterial host defense by down-regulating cathelicidin-related antimicrobial peptide in allergic inflammation mice and in lung epithelial cells

    PubMed Central

    2013-01-01

    Background Glucocorticoids are widely regarded as the most effective treatment for asthma. However, the direct impact of glucocorticoids on the innate immune system and antibacterial host defense during asthma remain unclear. Understanding the mechanisms underlying this process is critical to the clinical application of glucocorticoids for asthma therapy. After sensitization and challenge with ovalbumin (OVA), BALB/c mice were treated with inhaled budesonide and infected with Pseudomonas aeruginosa (P. aeruginosa). The number of viable bacteria in enflamed lungs was evaluated, and levels of interleukin-4 (IL-4) and interferon-γ (IFN-γ) in serum were measured. A lung epithelial cell line was pretreated with budesonide. Levels of cathelicidin-related antimicrobial peptide (CRAMP) were measured by immunohistochemistry and western blot analysis. Intracellular bacteria were observed in lung epithelial cells. Results Inhaled budesonide enhanced lung infection in allergic mice exposed to P. aeruginosa and increased the number of viable bacteria in lung tissue. Higher levels of IL-4 and lower levels of IFN-γ were observed in the serum. Budesonide decreased the expression of CRAMP, increased the number of internalized P. aeruginosa in OVA-challenged mice and in lung epithelial cell lines. These data indicate that inhaled budesonide can suppress pulmonary antibacterial host defense by down-regulating CRAMP in allergic inflammation mice and in cells in vitro. Conclusions Inhaled budesonide suppressed pulmonary antibacterial host defense in an asthmatic mouse model and in lung epithelium cells in vitro. This effect was dependent on the down-regulation of CRAMP. PMID:23387852

  10. Cryptic glucocorticoid receptor-binding sites pervade genomic NF-κB response elements.

    PubMed

    Hudson, William H; Vera, Ian Mitchelle S de; Nwachukwu, Jerome C; Weikum, Emily R; Herbst, Austin G; Yang, Qin; Bain, David L; Nettles, Kendall W; Kojetin, Douglas J; Ortlund, Eric A

    2018-04-06

    Glucocorticoids (GCs) are potent repressors of NF-κB activity, making them a preferred choice for treatment of inflammation-driven conditions. Despite the widespread use of GCs in the clinic, current models are inadequate to explain the role of the glucocorticoid receptor (GR) within this critical signaling pathway. GR binding directly to NF-κB itself-tethering in a DNA binding-independent manner-represents the standing model of how GCs inhibit NF-κB-driven transcription. We demonstrate that direct binding of GR to genomic NF-κB response elements (κBREs) mediates GR-driven repression of inflammatory gene expression. We report five crystal structures and solution NMR data of GR DBD-κBRE complexes, which reveal that GR recognizes a cryptic response element between the binding footprints of NF-κB subunits within κBREs. These cryptic sequences exhibit high sequence and functional conservation, suggesting that GR binding to κBREs is an evolutionarily conserved mechanism of controlling the inflammatory response.

  11. Glucocorticoids and Metabolic Control.

    PubMed

    Magomedova, Lilia; Cummins, Carolyn L

    2016-01-01

    In response to stress, the central nervous system initiates a signaling cascade, which leads to the production of glucocorticoids (GCs). GCs act through the glucocorticoid receptor (GR) to coordinate the appropriate cellular response with the primary goal of mobilizing the storage forms of carbon precursors to generate a continuous glucose supply for the brain. Although GCs are critical for maintaining energy homeostasis, excessive GC stimulation leads to a number of undesirable side effects, including hyperglycemia, insulin resistance, fatty liver, obesity, and muscle wasting leading to severe metabolic dysfunction. Summarized below are the diverse metabolic roles of glucocorticoids in energy homeostasis and dysregulation, focusing specifically on glucose, lipid, and protein metabolism.

  12. Short-term withdrawal from developmental exposure to cocaine activates the glucocorticoid receptor and alters spine dynamics.

    PubMed

    Caffino, Lucia; Giannotti, Giuseppe; Malpighi, Chiara; Racagni, Giorgio; Fumagalli, Fabio

    2015-10-01

    Although glucocorticoid receptors (GRs) contribute to the action of cocaine, their role following developmental exposure to the psychostimulant is still unknown. To address this issue, we exposed adolescent male rats to cocaine (20mg/kg/day) from post-natal day (PND) 28 to PND 42 and sacrificed them at PND 45 or 90. We studied the medial prefrontal cortex (mPFC), a brain region that is still developing during adolescence. In PND 45 rats we found enhanced GR transcription and translation as well as increased trafficking toward the nucleus of the receptor, with no alteration in plasma corticosterone levels. We also showed reduced expression of the GR co-chaperone FKBP51, that normally keeps the receptor in the cytoplasm, and increased expression of Src1, which cooperates in the activation of GR transcriptional activity, revealing that short withdrawal alters the finely tuned mechanisms regulating GR action. Since activation of GRs regulate dendritic spine morphology, we next investigated spine dynamics in cocaine-withdrawn rats. We found that PSD95, cofilin and F-actin, molecules regulating spine actin network, are reduced in the mPFC of PND 45 rats suggesting reduced spine density, confirmed by confocal imaging. Further, formation of filopodia, i.e. the inactive spines, is enhanced suggesting the formation of non-functional spines. Of note, no changes were found in molecules related to GR machinery or spine dynamics following long-term abstinence, i.e. in adult rats (PND 90). These findings demonstrate that short withdrawal promotes plastic changes in the developing brain via the dysregulation of the GR system and alterations in the spine network. Copyright © 2015 Elsevier B.V. and ECNP. All rights reserved.

  13. Transcriptional regulation of FoxO3 gene by glucocorticoids in murine myotubes

    PubMed Central

    Kuo, Taiyi; Liu, Patty H.; Chen, Tzu-Chieh; Lee, Rebecca A.; New, Jenny; Zhang, Danyun; Lei, Cassandra; Chau, Andy; Tang, Yicheng; Cheung, Edna

    2016-01-01

    Glucocorticoids and FoxO3 exert similar metabolic effects in skeletal muscle. FoxO3 gene expression was increased by dexamethasone (Dex), a synthetic glucocorticoid, both in vitro and in vivo. In C2C12 myotubes the increased expression is due to, at least in part, the elevated rate of FoxO3 gene transcription. In the mouse FoxO3 gene, we identified three glucocorticoid receptor (GR) binding regions (GBRs): one being upstream of the transcription start site, −17kbGBR; and two in introns, +45kbGBR and +71kbGBR. Together, these three GBRs contain four 15-bp glucocorticoid response elements (GREs). Micrococcal nuclease (MNase) assay revealed that Dex treatment increased the sensitivity to MNase in the GRE of +45kbGBR and +71kbGBR upon 30- and 60-min Dex treatment, respectively. Conversely, Dex treatment did not affect the chromatin structure near the −17kbGBR, in which the GRE is located in the linker region. Dex treatment also increased histone H3 and/or H4 acetylation in genomic regions near all three GBRs. Moreover, using chromatin conformation capture (3C) assay, we showed that Dex treatment increased the interaction between the −17kbGBR and two genomic regions: one located around +500 bp and the other around +73 kb. Finally, the transcriptional coregulator p300 was recruited to all three GBRs upon Dex treatment. The reduction of p300 expression decreased FoxO3 gene expression and Dex-stimulated interaction between distinct genomic regions of FoxO3 gene identified by 3C. Overall, our results demonstrate that glucocorticoids activated FoxO3 gene transcription through multiple GREs by chromatin structural change and DNA looping. PMID:26758684

  14. GPR39 (zinc receptor) knockout mice exhibit depression-like behavior and CREB/BDNF down-regulation in the hippocampus.

    PubMed

    Młyniec, Katarzyna; Budziszewska, Bogusława; Holst, Birgitte; Ostachowicz, Beata; Nowak, Gabriel

    2014-10-31

    Zinc may act as a neurotransmitter in the central nervous system by activation of the GPR39 metabotropic receptors. In the present study, we investigated whether GPR39 knockout would cause depressive-like and/or anxiety-like behavior, as measured by the forced swim test, tail suspension test, and light/dark test. We also investigated whether lack of GPR39 would change levels of cAMP response element-binding protein (CREB),brain-derived neurotrophic factor (BDNF) and tropomyosin related kinase B (TrkB) protein in the hippocampus and frontal cortex of GPR39 knockout mice subjected to the forced swim test, as measured by Western-blot analysis. In this study, GPR39 knockout mice showed an increased immobility time in both the forced swim test and tail suspension test, indicating depressive-like behavior and displayed anxiety-like phenotype. GPR39 knockout mice had lower CREB and BDNF levels in the hippocampus, but not in the frontal cortex, which indicates region specificity for the impaired CREB/BDNF pathway (which is important in antidepressant response) in the absence of GPR39. There were no changes in TrkB protein in either structure. In the present study, we also investigated activity in the hypothalamus-pituitary-adrenal axis under both zinc- and GPR39-deficient conditions. Zinc-deficient mice had higher serum corticosterone levels and lower glucocorticoid receptor levels in the hippocampus and frontal cortex. There were no changes in the GPR39 knockout mice in comparison with the wild-type control mice, which does not support a role of GPR39 in hypothalamus-pituitary-adrenal axis regulation. The results of this study indicate the involvement of the GPR39 Zn(2+)-sensing receptor in the pathophysiology of depression with component of anxiety. © The Author 2015. Published by Oxford University Press on behalf of CINP.

  15. Down-regulation of NR2B receptors partially contributes to analgesic effects of Gentiopicroside in persistent inflammatory pain.

    PubMed

    Chen, Lei; Liu, Jin-cheng; Zhang, Xiao-nan; Guo, Yan-yan; Xu, Zhao-hui; Cao, Wei; Sun, Xiao-li; Sun, Wen-ji; Zhao, Ming-Gao

    2008-06-01

    Gentiopicroside is one of the secoiridoid compound isolated from Gentiana lutea. It exhibits analgesic activities in the mice. The anterior cingulate cortex (ACC) is a forebrain structure known for its roles in pain transmission and modulation. Painful stimuli potentiate the prefrontal synaptic transmission and induce glutamate NMDA NR2B receptor expression in the ACC. But little is known about Gentiopicroside on the persistent inflammatory pain and chronic pain-induced synaptic transmission changes in the ACC. The present study was undertaken to investigate its analgesic activities and central synaptic modulation to the peripheral painful inflammation. Gentiopicroside produced significant analgesic effects against persistent inflammatory pain stimuli in mice. Systemic administration of Gentiopicroside significantly reversed NR2B over-expression during the chronic phases of persistent inflammation caused by hind-paw administration of complete Freunds adjuvant (CFA) in mice. Whole-cell patch clamp recordings revealed that Gentiopicroside significantly reduced NR2B receptors mediated postsynaptic currents in the ACC. Our findings provide strong evidence that analgesic effects of Gentiopicroside involve down-regulation of NR2B receptors in the ACC to persistent inflammatory pain.

  16. Kinetically Defined Mechanisms and Positions of Action of Two New Modulators of Glucocorticoid Receptor-regulated Gene Induction*

    PubMed Central

    Pradhan, Madhumita A.; Blackford, John A.; Devaiah, Ballachanda N.; Thompson, Petria S.; Chow, Carson C.; Singer, Dinah S.; Simons, S. Stoney

    2016-01-01

    Most of the steps in, and many of the factors contributing to, glucocorticoid receptor (GR)-regulated gene induction are currently unknown. A competition assay, based on a validated chemical kinetic model of steroid hormone action, is now used to identify two new factors (BRD4 and negative elongation factor (NELF)-E) and to define their sites and mechanisms of action. BRD4 is a kinase involved in numerous initial steps of gene induction. Consistent with its complicated biochemistry, BRD4 is shown to alter both the maximal activity (Amax) and the steroid concentration required for half-maximal induction (EC50) of GR-mediated gene expression by acting at a minimum of three different kinetically defined steps. The action at two of these steps is dependent on BRD4 concentration, whereas the third step requires the association of BRD4 with P-TEFb. BRD4 is also found to bind to NELF-E, a component of the NELF complex. Unexpectedly, NELF-E modifies GR induction in a manner that is independent of the NELF complex. Several of the kinetically defined steps of BRD4 in this study are proposed to be related to its known biochemical actions. However, novel actions of BRD4 and of NELF-E in GR-controlled gene induction have been uncovered. The model-based competition assay is also unique in being able to order, for the first time, the sites of action of the various reaction components: GR < Cdk9 < BRD4 ≤ induced gene < NELF-E. This ability to order factor actions will assist efforts to reduce the side effects of steroid treatments. PMID:26504077

  17. Glucocorticoid receptor contributes to the altered expression of hepatic cytochrome P450 upon cigarette smoking.

    PubMed

    Li, Xue; Yan, Zhongfang; Wu, Qi; Sun, Xin; Li, Fan; Zhang, Subei; Li, Kuan; Li, Li; Wu, Junping; Xu, Long; Feng, Jing; Ning, Wen; Liu, Zhixue; Chen, Huaiyong

    2016-12-01

    Cigarette smoking has been shown to cause pathological alterations in the liver. However, how hepatic metabolism is altered during cigarette smoking‑induced inflammation remains to be fully elucidated. In the present study, a rat model of smoking was established to examine the effects of cigarette smoking on inflammation, autophagy activity, and the expression of nuclear receptor and CYP in the liver. Elevated expression of interleukin 1β and activation of autophagy in the liver were observed upon smoking exposure in rats. Cigarette smoking induced a significant reduction in the mRNA expression levels of cytochromes, including cytochrome P450 (Cyp)1A2, Cyp2D4 and Cyp3A2. Accordingly, a decrease was also observed in glucocorticoid receptor (GR), a regulator of the expression of Cyp. Activation of the GR signal in human hepatic LO2 cells did not affect autophagic genes, however, it led to the upregulation of hCYP1A2, hCYP2C19 and hCYP3A4, and the downregulation of hCYP2C9. The GR antagonist, RU486, eliminated this effect, suggesting the importance of GR in liver metabolism upon cigarette smoking.

  18. Science review: Mechanisms of impaired adrenal function in sepsis and molecular actions of glucocorticoids

    PubMed Central

    Prigent, Hélène; Maxime, Virginie; Annane, Djillali

    2004-01-01

    This review describes current knowledge on the mechanisms that underlie glucocorticoid insufficiency in sepsis and the molecular action of glucocorticoids. In patients with severe sepsis, numerous factors predispose to glucocorticoid insufficiency, including drugs, coagulation disorders and inflammatory mediators. These factors may compromise the hypothalamic–pituitary axis (i.e. secondary adrenal insufficiency) or the adrenal glands (i.e. primary adrenal failure), or may impair glucocorticoid access to target cells (i.e. peripheral tissue resistance). Irreversible anatomical damages to the hypothalamus, pituitary, or adrenal glands rarely occur. Conversely, transient functional impairment in hormone synthesis may be a common complication of severe sepsis. Glucocorticoids interact with a specific cytosolic glucocorticoid receptor, which undergoes conformational changes, sheds heat shock proteins and translocates to the nucleus. Glucocorticoids may also interact with membrane binding sites at the surface of the cells. The molecular action of glucocorticoids results in genomic and nongenomic effects. Direct and indirect transcriptional and post-transcriptional effects related to the cytosolic glucocorticoid receptor account for the genomic effects. Nongenomic effects are probably subsequent to cytosolic interaction between the glucocorticoid receptor and proteins, or to interaction between glucocorticoids and specific membrane binding sites. PMID:15312206

  19. Farnesyl Pyrophosphate Inhibits Epithelialization and Wound Healing through the Glucocorticoid Receptor*

    PubMed Central

    Vukelic, Sasa; Stojadinovic, Olivera; Pastar, Irena; Vouthounis, Constantinos; Krzyzanowska, Agata; Das, Sharmistha; Samuels, Herbert H.; Tomic-Canic, Marjana

    2010-01-01

    Farnesyl pyrophosphate (FPP), a key intermediate in the mevalonate pathway and protein farnesylation, can act as an agonist for several nuclear hormone receptors. Here we show a novel mechanism by which FPP inhibits wound healing acting as an agonist for glucocorticoid receptor (GR). Elevation of endogenous FPP by the squalene synthetase inhibitor zaragozic acid A (ZGA) or addition of FPP to the cell culture medium results in activation and nuclear translocation of the GR, a known wound healing inhibitor. We used functional studies to evaluate the effects of FPP on wound healing. Both FPP and ZGA inhibited keratinocyte migration and epithelialization in vitro and ex vivo. These effects were independent of farnesylation and indicate that modulation of FPP levels in skin may be beneficial for wound healing. FPP inhibition of keratinocyte migration and wound healing proceeds, in part, by repression of the keratin 6 gene. Furthermore, we show that the 3-hydroxy-3-methylglutaryl-CoA-reductase inhibitor mevastatin, which blocks FPP formation, not only promotes epithelialization in acute wounds but also reverses the effect of ZGA on activation of the GR and inhibition of epithelialization. We conclude that FPP inhibits wound healing by acting as a GR agonist. Of special interest is that FPP is naturally present in cells prior to glucocorticoid synthesis and that FPP levels can be further altered by the statins. Therefore, our findings may provide a better understanding of the pleiotropic effects of statins as well as molecular mechanisms by which they may accelerate wound healing. PMID:19903814

  20. A translational approach to clinical practice via stress-responsive glucocorticoid receptor signaling.

    PubMed

    Juruena, Mario F; Agustini, Bruno; Cleare, Anthony J; Young, Allan H

    2017-01-01

    A recent article by Kwan and colleagues could elegantly demonstrate the necessary interaction between neuronal serotonin (5-HT) systems and the hypothalamic-pituitary-adrenal (HPA) axis through glucocorticoid receptors (GR), producing an adequate stress response, in this case, responding to hypoxia with an increase in hematopoietic stem and progenitor cells (HSPC). There is an intricate system connecting brain, body and mind and this exchange is only possible when all these systems-nervous, endocrine, and immune-have receptors on critical cells to receive information (via messenger molecules) from each of the other systems. There is evidence that the expression and function of GR in the hippocampus, mainly MR, is regulated by the stimulation of 5-HT receptors. Stressful stimuli increase 5-HT release and turnover in the hippocampus, and it seems reasonable to suggest that some of the changes in mineralocorticoid and GR expression may be mediated, in part at least, by the increase in 5-HT. Also serotonin and HPA axis dysfunctions have already been implicated in a variety of psychiatric disorders, especially depression. Early life stress (ELS) can have profound impact on these systems and can predispose subjects to a variety of adult metabolic and psychiatric conditions. It is important to analyze the mechanisms of this complex interaction and its subsequent programming effects on the stress systems, so that we can find new ways and targets for treatment of psychiatric disorders. Different areas of research on basic biological sciences are now being integrated and this approach will hopefully provide several new insights, new pharmacological targets and improve our global understanding of these highly debilitating chronic conditions, that we now call mental disorders.

  1. Epigenetic down regulation of G protein-coupled estrogen receptor (GPER) functions as a tumor suppressor in colorectal cancer.

    PubMed

    Liu, Qiao; Chen, Zhuojia; Jiang, Guanmin; Zhou, Yan; Yang, Xiangling; Huang, Hongbin; Liu, Huanliang; Du, Jun; Wang, Hongsheng

    2017-05-05

    Estrogenic signals are suggested to have protection roles in the development of colorectal cancer (CRC). The G protein-coupled estrogen receptor (GPER) has been reported to mediate non-genomic effects of estrogen in hormone related cancers except CRC. Its expression and functions in CRC were investigated. The expression of GPER and its associations with clinicopathological features were examined. The mechanisms were further investigated using cells, mouse xenograft models, and clinical human samples. GPER was significantly (p < 0.01) down regulated in CRC tissues compared with their matched adjacent normal tissues in our two cohorts and three independent investigations from Oncomine database. Patients whose tumors expressing less (n = 36) GPER showed significant (p < 0.01) poorer survival rate as compared with those with greater levels of GPER (n = 54). Promoter methylation and histone H3 deacetylation were involved in the down regulation of GPER in CRC cell lines and clinical tissues. Activation of GPER by its specific agonist G-1 inhibited proliferation, induced cell cycle arrest, mitochondrial-related apoptosis and endoplasmic reticulum (ER) stress of CRC cells. The upregulation of reactive oxygen species (ROS) induced sustained ERK1/2 activation participated in G-1 induced cell growth arrest. Further, G-1 can inhibit the phosphorylation, nuclear localization, and transcriptional activities of NF-κB via both canonical IKKα/ IκBα pathways and phosphorylation of GSK-3β. Xenograft model based on HCT-116 cells confirmed that G-1 can suppress the in vivo progression of CRC. Epigenetic down regulation of GPER acts as a tumor suppressor in colorectal cancer and its specific activation might be a potential approach for CRC treatment.

  2. Glucocorticoids interact with the hippocampal endocannabinoid system in impairing retrieval of contextual fear memory

    PubMed Central

    Atsak, Piray; Hauer, Daniela; Campolongo, Patrizia; Schelling, Gustav; McGaugh, James L.; Roozendaal, Benno

    2012-01-01

    There is extensive evidence that glucocorticoid hormones impair the retrieval of memory of emotionally arousing experiences. Although it is known that glucocorticoid effects on memory retrieval impairment depend on rapid interactions with arousal-induced noradrenergic activity, the exact mechanism underlying this presumably nongenomically mediated glucocorticoid action remains to be elucidated. Here, we show that the hippocampal endocannabinoid system, a rapidly activated retrograde messenger system, is involved in mediating glucocorticoid effects on retrieval of contextual fear memory. Systemic administration of corticosterone (0.3–3 mg/kg) to male Sprague–Dawley rats 1 h before retention testing impaired the retrieval of contextual fear memory without impairing the retrieval of auditory fear memory or directly affecting the expression of freezing behavior. Importantly, a blockade of hippocampal CB1 receptors with AM251 prevented the impairing effect of corticosterone on retrieval of contextual fear memory, whereas the same impairing dose of corticosterone increased hippocampal levels of the endocannabinoid 2-arachidonoylglycerol. We also found that antagonism of hippocampal β-adrenoceptor activity with local infusions of propranolol blocked the memory retrieval impairment induced by the CB receptor agonist WIN55,212–2. Thus, these findings strongly suggest that the endocannabinoid system plays an intermediary role in regulating rapid glucocorticoid effects on noradrenergic activity in impairing memory retrieval of emotionally arousing experiences. PMID:22331883

  3. BClI polymorphism of the glucocorticoid receptor gene is associated with increased obesity, impaired glucose metabolism and dyslipidaemia in patients with Addison's disease.

    PubMed

    Giordano, Roberta; Marzotti, Stefania; Berardelli, Rita; Karamouzis, Ioannis; Brozzetti, Annalisa; D'Angelo, Valentina; Mengozzi, Giulio; Mandrile, Giorgia; Giachino, Daniela; Migliaretti, Giuseppe; Bini, Vittorio; Falorni, Alberto; Ghigo, Ezio; Arvat, Emanuela

    2012-12-01

    Although glucocorticoids are essential for health, several studies have shown that glucocorticoids replacement in Addison's disease might be involved in anthropometric and metabolic impairment, with increased cardiovascular risk, namely if conventional doses are used. As the effects of glucocorticoids are mediated by the glucocorticoid receptor, encoded by NR3C1 gene, different polymorphisms in the NR3C1 gene have been linked to altered glucocorticoid sensitivity in general population as well as in patients with obesity or metabolic syndrome. We investigated the impact of glucocorticoid receptor gene polymorphisms, including the BclI, N363S and ER22/23EK variants, on anthropometric parameters (BMI and waist circumference), metabolic profile (HOMA, OGTT and serum lipids) and ACTH levels in 50 patients with Addison's disease (34 women and 16 men, age 20-82 year) under glucocorticoids replacement. Neither N363S nor ER22/23EK variants were significantly associated with anthropometric, metabolic or hormonal parameters, while patients carrying the homozygous BclI polymorphism GG (n = 4) showed higher (P < 0·05) BMI, waist circumference, HOMA and 2-h glucose levels after OGTT, as well as total cholesterol and triglycerides than those with wild-type genotype CC (n = 28) or heterozygous CG (n = 18). The totality of GG patients was connoted by abdominal adiposity, impaired glucose tolerance/diabetes mellitus or dyslipidaemia, while a lower percentage of CC or CG patients showed some anthropometric and metabolic alterations. These results suggest that BclI polymorphism may influence the sensitivity to glucocorticoids in patients with Addison's disease and may contribute, along with other factors, to the increase in central adiposity, impaired glucose metabolism and dyslipidaemia. © 2012 Blackwell Publishing Ltd.

  4. Glucocorticoid Signaling and Bone Biology.

    PubMed

    Komori, T

    2016-11-01

    Since glucocorticoids remain an effective therapeutic option for the treatment of many inflammatory and autoimmune diseases, glucocorticoid-induced osteoporosis is the most common form of secondary osteoporosis. Fractures may occur in as many as 30-50% of patients receiving chronic glucocorticoid therapy. Under physiological conditions, glucocorticoids are required for normal bone development due to their regulation of osteoblast differentiation, possibly via the Wnt/β-catenin pathway and TSC22D3. However, serum levels of endogenous corticosterone are elevated in aged mice and glucocorticoids exert negative effects on the survival of osteoblasts and osteocytes as well as angiogenesis. Glucocorticoid treatments impair bone formation and enhance bone resorption. Excess glucocorticoids induce osteoblast and osteocyte apoptosis by increasing pro-apoptotic molecules, reactive oxygen species, and endoplasmic reticulum stress and suppressing the Wnt/β-catenin pathway. Autophagy protects osteocytes from glucocorticoid-induced apoptosis, but passed some threshold, the process of autophagy leads the cells to apoptosis. Excess glucocorticoids impair osteoblastogenesis by inducing Wnt antagonists, including Dkk1, Sost, and sFRP-1. However, the findings are controversial and the involvement of Wnt antagonists requires further study. Excess glucocorticoids reduce the phosphorylation of Akt and GSK3β, which enhances the degradation of β-catenin. Excess glucocorticoids have been shown to modulate the expression of miRNAs, including miR-29a, miR-34a-5p, and miR-199a-5p, which regulate the proliferation and differentiation of osteoblast lineage cells. Excess glucocorticoids also enhance bone resorption by reducing OPG expression, increasing Rankl expression and reactive oxygen species, and prolonging the life span of osteoclasts; however, they also suppress the bone-degrading capacity of osteoclasts by disturbing the organization of the cytoskeleton. © Georg Thieme Verlag KG

  5. Effect of the glucocorticoid receptor antagonist RU486 on MK-801 induced behavioural sensitisation

    PubMed Central

    Lefevre, Emilia M.; Medley, Gregory A.; Reeks, Timothy; Alexander, Suzy; Burne, Thomas H. J.; Eyles, Darryl W.

    2017-01-01

    Stress is known to modulate sensitisation to repeated psychostimulant exposure. However, there is no direct evidence linking glucocorticoids and sensitisation achieved by repeated administration of the NMDA receptor antagonist MK-801. We tested the hypothesis that co-administration of RU486, a glucocorticoid receptor (GR) antagonist, prior to repeated daily MK-801 injections would block the expression of locomotor sensitisation due to its dual effects on corticosterone and dopamine. We employed a repeated MK-801 administration locomotor sensitisation paradigm in male Sprague Dawley rats. RU486 or a dimethyl sulfoxide (DMSO) vehicle was co-administered with MK-801 or saline during the induction phase. Subsequent to withdrawal, rats were challenged with MK-801 alone to test for the expression of sensitisation. In a separate cohort of rats, plasma corticosterone levels were quantified from blood samples taken on the 1st, 4th and 7th day of induction and at expression. One day after challenge, nucleus accumbens tissue levels of dopamine and its metabolites DOPAC and HVA were measured. During the induction phase, RU486 progressively enhanced locomotor sensitisation to MK-801. RU486 and MK-801 both showed stimulatory effects on corticosterone levels and this was further augmented when given in combination. Contrary to our hypothesis, RU486 did not block the expression of locomotor sensitisation to MK-801 and actually increased levels of dopamine, DOPAC and HVA in nucleus accumbens tissue. Our results showed that RU486 has augmentative rather than inhibitory effects on MK-801-induced sensitisation. This study indicates a divergent role for glucocorticoids in sensitisation to MK-801 compared to sensitisation with other psychostimulants. PMID:28430805

  6. Thymic involution in the suspended rat model for weightlessness - Decreased glucocorticoid receptor concentration

    NASA Technical Reports Server (NTRS)

    Steffen, J. M.; Musacchia, X. J.

    1984-01-01

    Hindlimb muscle atrophy, thymic involution and adrenal hypertrophy in rats during spaceflight can be simulated using suspension models. Skeletal muscle and thymus are sensitive to gluco-corticoids (GC), and previous studies have demonstrated that muscle atrophy in suspended rats is associated with increased GC receptor concentration. The objectives were to confirm thymic involution during suspension, and determine if involution correlated with increased GC receptor concentration. Seven days of antiorthostatic (AO) suspension of rats produced a significant (P less than 0.001) reduction in thymic wet weight not associated with an alteration of percent water content. GC receptor concentration (pmol/mg protein) decreased 20 percent (P less than 0.025) in thymus glands from 7 day AO suspended rats. Suspension, therefore, is associated with involution of the thymus, but this is not dependent upon AO positioning. Thymus GC receptor concentrations were depressed in 7-day suspended rats, in contrast with previous observations on skeletal muscle, suggesting that different mechanisms may underlie these responses.

  7. An Approach to Greater Specificity for Glucocorticoids

    PubMed Central

    Chow, Carson C.; Simons, S. Stoney

    2018-01-01

    Glucocorticoid steroids are among the most prescribed drugs each year. Nonetheless, the many undesirable side effects, and lack of selectivity, restrict their greater usage. Research to increase glucocorticoid specificity has spanned many years. These efforts have been hampered by the ability of glucocorticoids to both induce and repress gene transcription and also by the lack of success in defining any predictable properties that control glucocorticoid specificity. Correlations of transcriptional specificity have been observed with changes in steroid structure, receptor and chromatin conformation, DNA sequence for receptor binding, and associated cofactors. However, none of these studies have progressed to the point of being able to offer guidance for increased specificity. We summarize here a mathematical theory that allows a novel and quantifiable approach to increase selectivity. The theory applies to all three major actions of glucocorticoid receptors: induction by agonists, induction by antagonists, and repression by agonists. Simple graphical analysis of competition assays involving any two factors (steroid, chemical, peptide, protein, DNA, etc.) yields information (1) about the kinetically described mechanism of action for each factor at that step where the factor acts in the overall reaction sequence and (2) about the relative position of that step where each factor acts. These two pieces of information uniquely provide direction for increasing the specificity of glucocorticoid action. Consideration of all three modes of action indicate that the most promising approach for increased specificity is to vary the concentrations of those cofactors/pharmaceuticals that act closest to the observed end point. The potential for selectivity is even greater when varying cofactors/pharmaceuticals in conjunction with a select class of antagonists. PMID:29593646

  8. Blocking mineralocorticoid receptors impairs, blocking glucocorticoid receptors enhances memory retrieval in humans.

    PubMed

    Rimmele, Ulrike; Besedovsky, Luciana; Lange, Tanja; Born, Jan

    2013-04-01

    Memory retrieval is impaired at very low as well as very high cortisol levels, but not at intermediate levels. This inverted-U-shaped relationship between cortisol levels and memory retrieval may originate from different roles of the mineralocorticoid (MR) and glucocorticoid receptor (GR) that bind cortisol with distinctly different affinity. Here, we examined the role of MRs and GRs in human memory retrieval using specific receptor antagonists. In two double-blind within-subject, cross-over designed studies, young healthy men were asked to retrieve emotional and neutral texts and pictures (learnt 3 days earlier) between 0745 and 0915 hours in the morning, either after administration of 400 mg of the MR blocker spironolactone vs placebo (200 mg at 2300 hours and 200 mg at 0400 hours, Study I) or after administration of the GR blocker mifepristone vs placebo (200 mg at 2300 hours, Study II). Blockade of MRs impaired free recall of both texts and pictures particularly for emotional material. In contrast, blockade of GRs resulted in better memory retrieval for pictures, with the effect being more pronounced for neutral than emotional materials. These findings indicate indeed opposing roles of MRs and GRs in memory retrieval, with optimal retrieval at intermediate cortisol levels likely mediated by high MR but concurrently low GR activation.

  9. Placental glucocorticoid receptor and 11β-hydroxysteroid dehydrogenase-2 recruitment indicates impact of prenatal adversity upon postnatal development in mice.

    PubMed

    Gross, Moshe; Romi, Hava; Gilimovich, Yelena; Drori, Elyashiv; Pinhasov, Albert

    2018-04-12

    Prenatal stress may increase concentrations of maternal glucocorticoids, which restrict fetal growth, with variable impact upon postnatal development. Among key regulators of stress hormone effects are the glucocorticoid receptor (GR) and 11β-hydroxysteroid dehydrogenase-2 (11βHSD2), the enzyme that inactivates glucocorticoid. This study utilized mice selectively bred for social dominance (Dom) or submissiveness (Sub), respectively exhibiting resilience or sensitivity to stress, to test whether stress-induced alterations in placental GR and 11βHSD2 protein expression may mediate divergent effects of prenatal adversity upon postnatal development. Pregnant Dom and Sub dams underwent prenatal restraint stress (PRS) for 45 min on gestational days (GD) 15-17. PRS induced a similar spike in serum corticosterone concentrations of dams from each strain on GD15 (p < .001, n = 8), and impaired fetal growth (p < .01, n = 5 litters), although Dom placentae were larger than Sub placentae (p < .01). Among placentae from Dom dams, PRS elevated protein contents of both GR (p < .05, n = 5 litters) and 11βHSD2 (p < .01) on GD19. In contrast, GR contents were reduced among placentae from PRS-exposed Sub mice (p < .01), without changes in 11βHSD2 content. Correspondingly, Dom PRS pup growth recovered by PND14, yet Sub PRS pups remained underweight into adolescence (p < .0001, n = 40 pups). Thus, prenatal stress more strongly increased placental GR and 11βHSD2 levels among Dom mice than in Subs. Increased GR may improve placental function and up-regulate 11βHSD2 expression, protecting fetuses from effects of prenatal stress upon postnatal development. Placental recruitment of GR and 11βHSD2 are potential markers of stress-induced developmental disorders, in accordance with maternal resilience or sensitivity to stress.

  10. Maternal PTSD associates with greater glucocorticoid sensitivity in offspring of Holocaust survivors.

    PubMed

    Lehrner, Amy; Bierer, Linda M; Passarelli, Vincent; Pratchett, Laura C; Flory, Janine D; Bader, Heather N; Harris, Iris R; Bedi, Aarti; Daskalakis, Nikolaos P; Makotkine, Iouri; Yehuda, Rachel

    2014-02-01

    Intergenerational effects of trauma have been observed clinically in a wide range of populations, and parental PTSD has been associated with an increased risk for psychopathology in offspring. In studies of Holocaust survivor offspring, parental PTSD, and particularly maternal PTSD, has been associated with increased risk for PTSD, low basal urinary cortisol excretion and enhanced cortisol suppression in response to dexamethasone. Such findings implicate maternally derived glucocorticoid programming in the intergenerational transmission of trauma-related consequences, potentially resulting from in utero influences or early life experiences. This study investigated the relative influence of Holocaust exposure and PTSD in mothers and fathers on glucocorticoid sensitivity in offspring. Eighty Holocaust offspring and 15 offspring of non-exposed Jewish parents completed evaluations and provided blood and urine samples. Glucocorticoid sensitivity was evaluated using the lysozyme suppression test (LST), an in vitro measure of glucocorticoid receptor sensitivity in a peripheral tissue, the dexamethasone suppression test (DST), and 24-h urinary cortisol excretion. Maternal PTSD was associated with greater glucocorticoid sensitivity in offspring across all three measures of glucocorticoid function. An interaction of maternal and paternal PTSD on the DST and 24-h urinary cortisol showed an effect of decreased glucocorticoid sensitivity in offspring with paternal, but not maternal, PTSD. Although indirect, these findings are consistent with the hypothesis that epigenetic programming may be involved in the intergenerational transmission of trauma-related effects on glucocorticoid regulation. Published by Elsevier Ltd.

  11. Maternal PTSD associates with greater glucocorticoid sensitivity in offspring of Holocaust survivors

    PubMed Central

    Lehrner, Amy; Bierer, Linda M.; Passarelli, Vincent; Pratchett, Laura C.; Flory, Janine D.; Bader, Heather; Harris, Iris R.; Bedi, Aarti; Daskalakis, Nikolaos P.; Makotkine, Iouri; Yehuda, Rachel

    2014-01-01

    Intergenerational effects of trauma have been observed clinically in a wide range of populations, and parental PTSD has been associated with an increased risk for psychopathology in offspring. In studies of Holocaust survivor offspring, parental PTSD, and particularly maternal PTSD, has been associated with increased risk for PTSD, low basal urinary cortisol excretion and enhanced cortisol suppression in response to dexamethasone. Such findings implicate maternally derived glucocorticoid programming in the intergenerational transmission of trauma-related consequences, potentially resulting from in utero influences or early life experiences. This study investigated the relative influence of Holocaust exposure and PTSD in mothers and fathers on glucocorticoid sensitivity in offspring. Eighty Holocaust offspring and 15 offspring of non-exposed Jewish parents completed evaluations and provided blood and urine samples. Glucocorticoid sensitivity was evaluated using the lysozyme suppression test (LST), an in vitro measure of glucocorticoid receptor sensitivity in a peripheral tissue, the dexamethasone suppression test (DST), and 24 hour urinary cortisol excretion. Maternal PTSD was associated with greater glucocorticoid sensitivity in offspring across all three measures of glucocorticoid function. An interaction of maternal and paternal PTSD on the DST and 24-hr urinary cortisol showed an effect of decreased glucocorticoid sensitivity in offspring with paternal, but not maternal, PTSD. Although indirect, these findings are consistent with the hypothesis that epigenetic programming may be involved in the intergenerational transmission of trauma-related effects on glucocorticoid regulation. PMID:24485493

  12. microRNA-34a-Mediated Down-Regulation of the Microglial-Enriched Triggering Receptor and Phagocytosis-Sensor TREM2 in Age-Related Macular Degeneration.

    PubMed

    Bhattacharjee, Surjyadipta; Zhao, Yuhai; Dua, Prerna; Rogaev, Evgeny I; Lukiw, Walter J

    2016-01-01

    The aggregation of Aβ42-peptides and the formation of drusen in age-related macular degeneration (AMD) are due in part to the inability of homeostatic phagocytic mechanisms to clear self-aggregating Aβ42-peptides from the extracellular space. The triggering receptor expressed in myeloid/microglial cells-2 (TREM2), a trans-membrane-spanning, sensor-receptor of the immune-globulin/lectin-like gene superfamily is a critical component of Aβ42-peptide clearance. Here we report a significant deficit in TREM2 in AMD retina and in cytokine- or oxidatively-stressed microglial (MG) cells. RT-PCR, miRNA-array, LED-Northern and Western blot studies indicated up-regulation of a microglial-enriched NF-кB-sensitive miRNA-34a coupled to a down-regulation of TREM2 in the same samples. Bioinformatics/transfection-luciferase reporter assays indicated that miRNA-34a targets the 299 nucleotide TREM2-mRNA-3'UTR, resulting in TREM2 down-regulation. C8B4-microglial cells challenged with Aβ42 were able to phagocytose these peptides, while miRNA-34a down-regulated both TREM2 and the ability of microglial-cells to phagocytose. Treatment of TNFα-stressed MG cells with phenyl-butyl nitrone (PBN), caffeic-acid phenethyl ester (CAPE), the NF-kB - [corrected] inhibitor/resveratrol analog CAY10512 or curcumin abrogated these responses. Incubation of anti-miRNA-34a (AM-34a) normalized miRNA-34a abundance and restored TREM2 back to homeostatic levels. These data support five novel observations: (i) that a ROS- and NF-kB - [corrected] sensitive, miRNA-34a-mediated modulation of TREM2 may in part regulate the phagocytic response; (ii) that gene products encoded on two different chromosomes (miRNA-34a at chr1q36.22 and TREM2 at chr6p21.1) orchestrate a phagocytic-Aβ42-peptide clearance-system; (iii) that this NF-kB-mediated-miRNA-34a-TREM2 mechanism is inducible from outside of the cell; (iv) that when operating normally, this pathway can clear Aβ42 peptide monomers from the extracellular

  13. microRNA-34a-Mediated Down-Regulation of the Microglial-Enriched Triggering Receptor and Phagocytosis-Sensor TREM2 in Age-Related Macular Degeneration

    PubMed Central

    Dua, Prerna; Rogaev, Evgeny I.; Lukiw, Walter J.

    2016-01-01

    The aggregation of Aβ42-peptides and the formation of drusen in age-related macular degeneration (AMD) are due in part to the inability of homeostatic phagocytic mechanisms to clear self-aggregating Aβ42-peptides from the extracellular space. The triggering receptor expressed in myeloid/microglial cells-2 (TREM2), a trans-membrane-spanning, sensor-receptor of the immune-globulin/lectin-like gene superfamily is a critical component of Aβ42-peptide clearance. Here we report a significant deficit in TREM2 in AMD retina and in cytokine- or oxidatively-stressed microglial (MG) cells. RT-PCR, miRNA-array, LED-Northern and Western blot studies indicated up-regulation of a microglial-enriched NF-кB-sensitive miRNA-34a coupled to a down-regulation of TREM2 in the same samples. Bioinformatics/transfection-luciferase reporter assays indicated that miRNA-34a targets the 299 nucleotide TREM2-mRNA-3’UTR, resulting in TREM2 down-regulation. C8B4-microglial cells challenged with Aβ42 were able to phagocytose these peptides, while miRNA-34a down-regulated both TREM2 and the ability of microglial-cells to phagocytose. Treatment of TNFα-stressed MG cells with phenyl-butyl nitrone (PBN), caffeic-acid phenethyl ester (CAPE), the NF-B-inhibitor/resveratrol analog CAY10512 or curcumin abrogated these responses. Incubation of anti-miRNA-34a (AM-34a) normalized miRNA-34a abundance and restored TREM2 back to homeostatic levels. These data support five novel observations: (i) that a ROS- and NF-B-sensitive, miRNA-34a-mediated modulation of TREM2 may in part regulate the phagocytic response; (ii) that gene products encoded on two different chromosomes (miRNA-34a at chr1q36.22 and TREM2 at chr6p21.1) orchestrate a phagocytic-Aβ42-peptide clearance-system; (iii) that this NF-kB-mediated-miRNA-34a-TREM2 mechanism is inducible from outside of the cell; (iv) that when operating normally, this pathway can clear Aβ42 peptide monomers from the extracellular medium; and (v) that anti

  14. Src-like adaptor protein down-regulates T cell receptor (TCR)-CD3 expression by targeting TCRzeta for degradation.

    PubMed

    Myers, Margaret D; Dragone, Leonard L; Weiss, Arthur

    2005-07-18

    Src-like adaptor protein (SLAP) down-regulates expression of the T cell receptor (TCR)-CD3 complex during a specific stage of thymocyte development when the TCR repertoire is selected. Consequently, SLAP-/- thymocytes display alterations in thymocyte development. Here, we have studied the mechanism of SLAP function. We demonstrate that SLAP-deficient thymocytes have increased TCRzeta chain expression as a result of a defect in TCRzeta degradation. Failure to degrade TCRzeta leads to an increased pool of fully assembled TCR-CD3 complexes that are capable of recycling back to the cell surface. We also provide evidence that SLAP functions in a pathway that requires the phosphorylated TCRzeta chain and the Src family kinase Lck, but not ZAP-70 (zeta-associated protein of 70 kD). These studies reveal a unique mechanism by which SLAP contributes to the regulation of TCR expression during a distinct stage of thymocyte development.

  15. Glucocorticoid action in human corneal epithelial cells establishes roles for corticosteroids in wound healing and barrier function of the eye.

    PubMed

    Kadmiel, Mahita; Janoshazi, Agnes; Xu, Xiaojiang; Cidlowski, John A

    2016-11-01

    Glucocorticoids play diverse roles in almost all physiological systems of the body, including both anti-inflammatory and immunosuppressive roles. Synthetic glucocorticoids are one of the most widely prescribed drugs and are used in the treatment of conditions such as autoimmune diseases, allergies, ocular disorders and certain types of cancers. In the interest of investigating glucocorticoid actions in the cornea of the eye, we established that multiple cell types in mouse corneas express functional glucocorticoid receptor (GR) with corneal epithelial cells having robust expression. To define glucocorticoid actions in a cell type-specific manner, we employed immortalized human corneal epithelial (HCE) cell line to define the glucocorticoid transcriptome and elucidated its functions in corneal epithelial cells. Over 4000 genes were significantly regulated within 6 h of dexamethasone treatment, and genes associated with cell movement, cytoskeletal remodeling and permeability were highly regulated. Real-time in vitro wound healing assays revealed that glucocorticoids delay wound healing by attenuating cell migration. These functional alterations were associated with cytoskeletal remodeling at the wounded edge of a scratch-wounded monolayer. However, glucocorticoid treatment improved the organization of tight-junction proteins and enhanced the epithelial barrier function. Our results demonstrate that glucocorticoids profoundly alter corneal epithelial gene expression and many of these changes likely impact both wound healing and epithelial cell barrier function. Published by Elsevier Ltd.

  16. Differential regulation of oligodendrocyte markers by glucocorticoids: Post-transcriptional regulation of both proteolipid protein and myelin basic protein and transcriptional regulation of glycerol phosphate dehydrogenase

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Kumar, S.; Cole, R.; Chiappelli, F.

    During neonatal development glucocorticoids potentiate oligodendrocyte differentiation and myelinogenesis by regulating the expression of myelin basic protein, proteolipid protein, and glycerol phosphate dehydrogenase. The actual locus at which hydrocortisone exerts its developmental influence on glial physiology is, however, not well understood. Gycerol phosphate dehydrogenase is glucocorticoid-inducible in oligodendrocytes at all stages of development both in vivo and in vitro. In newborn rat cerebral cultures, between 9 and 15 days in vitro, a 2- to 3-fold increase in myelin basic protein and proteolipid protein mRNA levels occurs in oligodendrocytes within 12 hr of hydrocortisone treatment. Immunostaining demonstrates that this increase inmore » mRNAs is followed by a 2- to 3-fold increase in the protein levels within 24 hr. In vitro transcription assays performed with oligodendrocyte nuclei show an 11-fold increase in the transcriptional activity of glycerol phosphate dehydrogenase in response to hydrocortisone but no increase in transcription of myelin basic protein or proteolipid protein. These results indicate that during early myelinogeneis, glucocorticoids influence the expression of key oligodendroglial markers by different processes: The expression of glycerol phosphate dehydrogenase is regulated at the transcriptional level, whereas the expression of myelin basic protein and proteolipid protein is modulated via a different, yet uncharacterized, mechanism involving post-transcriptional regulation.« less

  17. The glucocorticoid receptor gene polymorphism N363S predisposes to more severe toxic side effects during pediatric acute lymphoblastic leukemia (ALL) therapy.

    PubMed

    Eipel, O T; Németh, K; Török, D; Csordás, K; Hegyi, M; Ponyi, A; Ferenczy, A; Erdélyi, D J; Csóka, M; Kovács, G T

    2013-02-01

    The survival rates in childhood acute lymphoid leukemia (ALL) have improved dramatically; however, patients still suffer from a variety of drug-related toxicities. Individualized therapy regimens promise the least toxic therapy regimen with the best hematologic outcome. Our aim was to investigate whether increased individual glucocorticoid sensitivity due to the N363S polymorphism of the glucocorticoid receptor increased susceptibility to steroid-related toxicities during ALL therapy. A total of 346 pediatric ALL patients were involved in the present study. N363S carrier status was investigated by allele-specific PCR. Clinical and laboratory signs of glucocorticoid-related toxicities, Day 8 prednisone response, and 5-year event-free survival were analyzed and compared retrospectively. Thirty-two of the 346 patients were heterozygous carriers (9.2 %). Hepatotoxicity (31.3 vs. 11.2 %, p = 0.004, carriers and non-carriers, respectively) and glucose metabolism abnormalities (18.8 vs. 3.8 %, p = 0.001, carriers and non-carriers, respectively) were significantly more frequent among carriers. There was no difference in the incidence of hypertension and encephalopathy/psychosis among carriers and non-carriers. Carriers were also more prone to have a combination of toxicities. All 363S carriers were good prednisone responders (100 %) and had significantly better 5-year event-free survival rates (93.1 vs. 71.86 %, p = 0.012), whereas among non-carriers there were more poor prednisone responders (8.28 %) and worse 5-year event-free survival rates. Patients with the N363S polymorphism in the glucocorticoid receptor are more prone to steroid-related toxicity during ALL therapy and should be monitored more closely. Patients with N363S polymorphism of the glucocorticoid receptor may be appropriate candidates for inclusion in the design of individualized therapies.

  18. Effects of acute restraint-induced stress on glucocorticoid receptors and brain-derived neurotrophic factor after mild traumatic brain injury.

    PubMed

    Griesbach, G S; Vincelli, J; Tio, D L; Hovda, D A

    2012-05-17

    We have previously reported that experimental mild traumatic brain injury results in increased sensitivity to stressful events during the first post-injury weeks, as determined by analyzing the hypothalamic-pituitary-adrenal (HPA) axis regulation following restraint-induced stress. This is the same time period when rehabilitative exercise has proven to be ineffective after a mild fluid-percussion injury (FPI). Here we evaluated effects of stress on neuroplasticity. Adult male rats underwent either an FPI or sham injury. Additional rats were only exposed to anesthesia. Rats were exposed to 30 min of restraint stress, followed by tail vein blood collection at post-injury days (PID) 1, 7, and 14. The response to dexamethasone (DEX) was also evaluated. Hippocampal tissue was collected 120 min after stress onset. Brain-derived neurotrophic factor (BDNF) along with glucocorticoid (GR) and mineralocorticoid (MR) receptors was determined by Western blot analysis. Results indicated injury-dependent changes in glucocorticoid and mineralocorticoid receptors that were influenced by the presence of dexamethasone. Control and FPI rats responded differentially to DEX in that GR increases after receiving the lower dose of DEX were longer lasting in the FPI group. A suppression of MR was found at PID 1 in vehicle-treated FPI and Sham groups. Decreases in the precursor form of BDNF were observed in different FPI groups at PIDs 7 and 14. These findings suggest that the increased sensitivity to stressful events during the first post-injury weeks, after a mild FPI, has an impact on hippocampal neuroplasticity. Copyright © 2012 IBRO. Published by Elsevier Ltd. All rights reserved.

  19. Novel down-regulatory mechanism of the surface expression of the vasopressin V2 receptor by an alternative splice receptor variant.

    PubMed

    Sarmiento, José M; Añazco, Carolina C; Campos, Danae M; Prado, Gregory N; Navarro, Javier; González, Carlos B

    2004-11-05

    In rat kidney, two alternatively spliced transcripts are generated from the V2 vasopressin receptor gene. The large transcript (1.2 kb) encodes the canonical V2 receptor, whereas the small transcript encodes a splice variant displaying a distinct sequence corresponding to the putative seventh transmembrane domain and the intracellular C terminus of the V2 receptor. This work showed that the small spliced transcript is translated in the rat kidney collecting tubules. However, the protein encoded by the small transcript (here called the V2b splice variant) is retained inside the cell, in contrast to the preferential surface distribution of the V2 receptor (here called the V2a receptor). Cells expressing the V2b splice variant do not exhibit binding to 3H-labeled vasopressin. Interestingly, we found that expression of the splice variant V2b down-regulates the surface expression of the V2a receptor, most likely via the formation of V2a.V2b heterodimers as demonstrated by co-immunoprecipitation and fluorescence resonance energy transfer experiments between the V2a receptor and the V2b splice variant. The V2b splice variant would then be acting as a dominant negative. The effect of the V2b splice variant is specific, as it does not affect the surface expression of the G protein-coupled interleukin-8 receptor (CXCR1). Furthermore, the sequence encompassing residues 242-339, corresponding to the C-terminal domain of the V2b splice variant, also down-regulates the surface expression of the V2a receptor. We suggest that some forms of nephrogenic diabetes insipidus are due to overexpression of the splice variant V2b, which could retain the wild-type V2a receptor inside the cell via the formation of V2a.V2b heterodimers.

  20. The regulation of delta-opiate receptor density on 108CC15 neuroblastoma X glioma hybrid cells.

    PubMed Central

    Moses, M. A.; Snell, C. R.

    1984-01-01

    The effect of exogenous substances on the expression of opiate receptors on 108CC15 neuroblastoma X glioma hybrid cells has been studied. Cell differentiation by culture in the presence of N6-O2-dibutyryl adenosine 3',5'-cyclic monophosphate induced a three fold increase in opiate receptor density. When the cells were grown in the presence of 10(-5) M morphine hydrochloride for up to 23 days, opiate receptor densities were reduced by only 30% when compared with matched controls. Culture in the presence of 10(-7) M D-Ala2-D-Leu5-enkephalin produced opiate receptor down regulation of 73% compared to controls after only 4 h of treatment. The down regulation process could be inhibited by continued exposure to D-Ala2 D-Leu5-enkephalin at concentrations greater than 4 nM; below this concentration down regulation was rapid and irreversible. A model to explain these observations is described. PMID:6322893

  1. Regulation of blood glucose level by kainic acid in mice: involvement of glucocorticoid system and non-NMDA receptors.

    PubMed

    Kim, Chea-Ha; Park, Soo-Hyun; Sim, Yun-Beom; Kim, Sung-Su; Jung, Jun-Sub; Sharma, Naveen; Suh, Hong-Won

    2017-02-28

    Kainic acid (KA) is a well-known excitatory neurotoxic substance. In the present study, effects of KA-injected intraperitoneally (i.p.), intracerebroventricularly (i.c.v.) or intrathecally (i.t.) on the blood glucose level were investigated in ICR mice. We found that KA administered intraperitoneally (i.p.), intracerebroventricularly (i.c.v.) or intrathecally (i.t.) increased the blood glucose and corticosterone levels, suggesting that KA-induced hyperglycemia appeared to be due to increased blood corticosterone level. In support of this finding, adrenalectomy causes a reduction of KA-induced hyperglycemia and neuronal cell death in CA3 regions of the hippocampus. In addition, pretreatment with i.c.v. or i.t. injection of CNQX (6-cyano-7-nitroquinoxaline-2, 3-dione; a non-NMDA receptor blocker) attenuated the i.p. and i.c.v. administered KA-induced hyperglycemia. KA administered i.c.v. caused an elevation of the blood corticosterone level whereas the plasma insulin level was reduced. Moreover, i.c.v. pretreatment with CNQX inhibited the decrease of plasma insulin level induced by KA i.c.v. injection, whereas the KA-induced plasma corticosterone level was further enhanced by CNQX pretreatment. Our results suggest that KA administered systemically or centrally produces hyperglycemia. A glucocorticoid system appears to be involved in KA-induced hyperglycemia. Furthermore, central non-N-methyl-D-aspartate receptors may be responsible for KA-induced hyperglycemia.

  2. Autoregulation of human relaxin-2 gene expression critically involves relaxin and glucocorticoid receptor binding to glucocorticoid response half-sites in the relaxin-2 promoter.

    PubMed

    Dschietzig, Thomas; Bartsch, Cornelia; Wessler, Silja; Baumann, Gert; Stangl, Karl

    2009-06-05

    Relaxin peptides act in brain, reproductive and cardiovascular systems, kidneys, and connective tissue through different G protein-coupled receptors. We reported that human relaxin-2 and porcine relaxin are both agonists at the human glucocorticoid receptor (GR). Here, we investigated the possible auto-regulation of relaxin-2 gene expression via recently discovered GR-binding sites in the relaxin-2 promoter. We found that porcine relaxin increased the secretion of human relaxin-like immunoreactivity in HeLa and THP-1 cells. Silencing of GR gene expression completely abolished this effect whereas transfection of wild-type GR into naturally GR-devoid HT-29 cells established relaxin sensitivity. Relaxin was shown to stimulate CAT expression driven by different deletion constructs of the 5'-flanking region of the relaxin-2 promoter. In chromatin immunoprecipitation assays, we detected both GR and relaxin binding to the relaxin-2 promoter. Gel shift assays indicated binding of relaxin-activated GR to half-GREs located between 160 and 200 bp upstream of transcription start but not to the GRE at -900 bp. Relaxin bound to human GR and displaced established GR agonists. Immunofluorescence experiments visualized nuclear co-localization of relaxin and GR in response to relaxin. In conclusion, we have identified a positive auto-regulatory loop of human relaxin-2 expression which involves GR and relaxin/GR binding to half-GREs in the relaxin-2 promoter.

  3. Glucocorticoid-Mediated Repression of the Oncogenic microRNA Cluster miR-17∼92 Contributes to the Induction of Bim and Initiation of Apoptosis

    PubMed Central

    Molitoris, Jason K.; McColl, Karen S.

    2011-01-01

    Synthetic glucocorticoids were one of the first effective treatments for lymphoid malignancies because of their ability to induce apoptosis and are still used in combination with other chemotherapeutic agents. Up-regulation of Bim, a proapoptotic member of the B-cell lymphoma-2 family, is an important mediator of glucocorticoid-induced apoptosis. Although glucocorticoids are known to elevate Bim mRNA and protein, little is known about the mechanism. Here, we report that glucocorticoids repress the expression of the microRNA cluster miR-17∼92, which results in elevated Bim protein expression as a mechanism by which glucocorticoids induce Bim. Using a luciferase-Bim 3′ untranslated region construct, we demonstrate that glucocorticoids mediate Bim induction posttranscriptionally after miR-17∼92 repression, resulting in increased Bim protein expression. Overexpression of miR-17∼92 microRNAs decreases Bim induction and attenuates glucocorticoid-mediated apoptosis. Conversely, knockdown of miR-17∼92 increases Bim protein expression and glucocorticoid-mediated apoptosis. These findings indicate that endogenous levels of miR-17∼92 repress Bim expression in T-cell lymphoid malignancies and that glucocorticoids induce Bim expression via down-regulation of the miR-17∼92 microRNA cluster. Our findings present a novel mechanism that contributes to the up-regulation of Bim and induction of apoptosis in lymphocytes after glucocorticoid treatment. Furthermore, our work demonstrating that inhibition of miR-17∼92 increases glucocorticoid-induced apoptosis highlights the potential importance of miR-17∼92 as a therapeutic target in leukemias and lymphomas. PMID:21239610

  4. Glucocorticoid Regulation of Food-Choice Behavior in Humans: Evidence from Cushing's Syndrome

    PubMed Central

    Moeller, Scott J.; Couto, Lizette; Cohen, Vanessa; Lalazar, Yelena; Makotkine, Iouri; Williams, Nia; Yehuda, Rachel; Goldstein, Rita Z.; Geer, Eliza B.

    2016-01-01

    The mechanisms by which glucocorticoids regulate food intake and resulting body mass in humans are not well-understood. One potential mechanism could involve modulation of reward processing, but human stress models examining effects of glucocorticoids on behavior contain important confounds. Here, we studied individuals with Cushing's syndrome, a rare endocrine disorder characterized by chronic excess endogenous glucocorticoids. Twenty-three patients with Cushing's syndrome (13 with active disease; 10 with disease in remission) and 15 controls with a comparably high body mass index (BMI) completed two simulated food-choice tasks (one with “explicit” task contingencies and one with “probabilistic” task contingencies), during which they indicated their objective preference for viewing high calorie food images vs. standardized pleasant, unpleasant, and neutral images. All participants also completed measures of food craving, and approximately half of the participants provided 24-h urine samples for assessment of cortisol and cortisone concentrations. Results showed that on the explicit task (but not the probabilistic task), participants with active Cushing's syndrome made fewer food-related choices than participants with Cushing's syndrome in remission, who in turn made fewer food-related choices than overweight controls. Corroborating this group effect, higher urine cortisone was negatively correlated with food-related choice in the subsample of all participants for whom these data were available. On the probabilistic task, despite a lack of group differences, higher food-related choice correlated with higher state and trait food craving in active Cushing's patients. Taken together, relative to overweight controls, Cushing's patients, particularly those with active disease, displayed a reduced vigor of responding for food rewards that was presumably attributable to glucocorticoid abnormalities. Beyond Cushing's, these results may have relevance for

  5. Glucocorticoid Regulation of Food-Choice Behavior in Humans: Evidence from Cushing's Syndrome.

    PubMed

    Moeller, Scott J; Couto, Lizette; Cohen, Vanessa; Lalazar, Yelena; Makotkine, Iouri; Williams, Nia; Yehuda, Rachel; Goldstein, Rita Z; Geer, Eliza B

    2016-01-01

    The mechanisms by which glucocorticoids regulate food intake and resulting body mass in humans are not well-understood. One potential mechanism could involve modulation of reward processing, but human stress models examining effects of glucocorticoids on behavior contain important confounds. Here, we studied individuals with Cushing's syndrome, a rare endocrine disorder characterized by chronic excess endogenous glucocorticoids. Twenty-three patients with Cushing's syndrome (13 with active disease; 10 with disease in remission) and 15 controls with a comparably high body mass index (BMI) completed two simulated food-choice tasks (one with "explicit" task contingencies and one with "probabilistic" task contingencies), during which they indicated their objective preference for viewing high calorie food images vs. standardized pleasant, unpleasant, and neutral images. All participants also completed measures of food craving, and approximately half of the participants provided 24-h urine samples for assessment of cortisol and cortisone concentrations. Results showed that on the explicit task (but not the probabilistic task), participants with active Cushing's syndrome made fewer food-related choices than participants with Cushing's syndrome in remission, who in turn made fewer food-related choices than overweight controls. Corroborating this group effect, higher urine cortisone was negatively correlated with food-related choice in the subsample of all participants for whom these data were available. On the probabilistic task, despite a lack of group differences, higher food-related choice correlated with higher state and trait food craving in active Cushing's patients. Taken together, relative to overweight controls, Cushing's patients, particularly those with active disease, displayed a reduced vigor of responding for food rewards that was presumably attributable to glucocorticoid abnormalities. Beyond Cushing's, these results may have relevance for elucidating

  6. Acute stress-induced sensitization of the pituitary-adrenal response to heterotypic stressors: independence of glucocorticoid release and activation of CRH1 receptors.

    PubMed

    Belda, Xavier; Daviu, Núria; Nadal, Roser; Armario, Antonio

    2012-09-01

    A single exposure to some severe stressors causes sensitization of the hypothalamic-pituitary-adrenal (HPA) response to novel stressors. However, the putative factors involved in stress-induced sensitization are not known. In the present work we studied in adult male rats the possible role of glucocorticoids and CRH type 1 receptor (CRH-R1), using an inhibitor of glucocorticoid synthesis (metyrapone, MET), the glucocorticoid receptor (GR) antagonist RU38486 (mifepristone) and the non-peptide CRH-R1 antagonist R121919. In a first experiment we demonstrated with different doses of MET (40-150 mg/kg) that the highest dose acted as a pharmacological stressor greatly increasing ACTH release and altering the normal circadian pattern of HPA hormones, but no dose affected ACTH responsiveness to a novel environment as assessed 3 days after drug administration. In a second experiment, we found that MET, at a dose (75 mg/kg) that blocked the corticosterone response to immobilization (IMO), did not alter IMO-induced ACTH sensitization. Finally, neither the GR nor the CRH-R1 antagonists blocked IMO-induced ACTH sensitization on the day after IMO. Thus, a high dose of MET, in contrast to IMO, was unable to sensitize the HPA response to a novel environment despite the huge activation of the HPA axis caused by the drug. Neither a moderate dose of MET that markedly reduced corticosterone response to IMO, nor the blockade of GR or CRH-R1 receptors was able to alter stress-induced HPA sensitization. Therefore, stress-induced sensitization is not the mere consequence of a marked HPA activation and does not involve activation of glucocorticoid or CRH-R1 receptors. Copyright © 2012 Elsevier Inc. All rights reserved.

  7. Toll-like Receptor-mediated Down-regulation of the Deubiquitinase Cylindromatosis (CYLD) Protects Macrophages from Necroptosis in Wild-derived Mice*

    PubMed Central

    Schworer, Stephen A.; Smirnova, Irina I.; Kurbatova, Irina; Bagina, Uliana; Churova, Maria; Fowler, Trent; Roy, Ananda L.; Degterev, Alexei; Poltorak, Alexander

    2014-01-01

    Pathogen recognition by the innate immune system initiates the production of proinflammatory cytokines but can also lead to programmed host cell death. Necroptosis, a caspase-independent cell death pathway, can contribute to the host defense against pathogens or cause damage to host tissues. Receptor-interacting protein (RIP1) is a serine/threonine kinase that integrates inflammatory and necroptotic responses. To investigate the mechanisms of RIP1-mediated activation of immune cells, we established a genetic screen on the basis of RIP1-mediated necroptosis in wild-derived MOLF/EiJ mice, which diverged from classical laboratory mice over a million years ago. When compared with C57BL/6, MOLF/EiJ macrophages were resistant to RIP1-mediated necroptosis induced by Toll-like receptors. Using a forward genetic approach in a backcross panel of mice, we identified cylindromatosis (CYLD), a deubiquitinase known to act directly on RIP1 and promote necroptosis in TNF receptor signaling, as the gene conferring the trait. We demonstrate that CYLD is required for Toll-like receptor-induced necroptosis and describe a novel mechanism by which CYLD is down-regulated at the transcriptional level in MOLF/EiJ macrophages to confer protection from necroptosis. PMID:24706750

  8. 9β Polymorphism of the glucocorticoid receptor gene appears to have limited impact in patients with Addison's disease.

    PubMed

    Ross, Ian Louis; Dandara, Collet; Swart, Marelize; Lacerda, Miguel; Schatz, Desmond; Blom, Dirk Jacobus

    2014-01-01

    Addison's disease (AD) has been associated with an increased risk of cardiovascular disease. Glucocorticoid receptor polymorphisms that alter glucocorticoid sensitivity may influence metabolic and cardiovascular risk factors in patients with AD. The 9β polymorphism of the glucocorticoid receptor gene is associated with relative glucocorticoid resistance and has been reported to increase the risk of myocardial infarction in the elderly. We explored the impact of this polymorphism in patients with AD. 147 patients with AD and 147 age, gender and ethnicity matched healthy controls were recruited. Blood was taken in a non-fasted state for plasma lipid determination, measurement of cardiovascular risk factors and DNA extraction. Genotype data for the 9β polymorphism was available for 139 patients and 146 controls. AD patients had a more atherogenic lipid profile characterized by an increase in the prevalence of small dense LDL (p = 0.003), increased triglycerides (p = 0.002), reduced HDLC (p<0.001) an elevated highly sensitive C-reactive protein (p = 0.01), compared with controls. The 9β polymorphism (at least one G allele) was found in 28% of patients and controls respectively. After adjusting for age, gender, ethnicity, BMI and hydrocortisone dose per metre square of body surface area in patients, there were no significant metabolic associations with this polymorphism and hydrocortisone doses were not higher in patients with the polymorphism. This study did not identify any associations between the 9β polymorphism and cardiovascular risk factors or hydrocortisone dose and determination of this polymorphism is therefore unlikely to be of clinical benefit in the management of patients with AD.

  9. Blocking Mineralocorticoid Receptors Impairs, Blocking Glucocorticoid Receptors Enhances Memory Retrieval in Humans

    PubMed Central

    Rimmele, Ulrike; Besedovsky, Luciana; Lange, Tanja; Born, Jan

    2013-01-01

    Memory retrieval is impaired at very low as well as very high cortisol levels, but not at intermediate levels. This inverted-U-shaped relationship between cortisol levels and memory retrieval may originate from different roles of the mineralocorticoid (MR) and glucocorticoid receptor (GR) that bind cortisol with distinctly different affinity. Here, we examined the role of MRs and GRs in human memory retrieval using specific receptor antagonists. In two double-blind within-subject, cross-over designed studies, young healthy men were asked to retrieve emotional and neutral texts and pictures (learnt 3 days earlier) between 0745 and 0915 hours in the morning, either after administration of 400 mg of the MR blocker spironolactone vs placebo (200 mg at 2300 hours and 200 mg at 0400 hours, Study I) or after administration of the GR blocker mifepristone vs placebo (200 mg at 2300 hours, Study II). Blockade of MRs impaired free recall of both texts and pictures particularly for emotional material. In contrast, blockade of GRs resulted in better memory retrieval for pictures, with the effect being more pronounced for neutral than emotional materials. These findings indicate indeed opposing roles of MRs and GRs in memory retrieval, with optimal retrieval at intermediate cortisol levels likely mediated by high MR but concurrently low GR activation. PMID:23303058

  10. IL-20 is epigenetically regulated in NSCLC and down regulates the expression of VEGF.

    PubMed

    Baird, Anne-Marie; Gray, Steven G; O'Byrne, Kenneth J

    2011-08-01

    IL-20 is a pleiotrophic member of the IL-10 family and plays a role in skin biology and the development of haematopoietic cells. Recently, IL-20 has been demonstrated to have potential anti-angiogenic effects in non-small cell lung cancer (NSCLC) by down regulating COX-2. The expression of IL-20 and its cognate receptors (IL-20RA/B and IL-22R1) was examined in a series of resected fresh frozen NSCLC tumours. Additionally, the expression and epigenetic regulation of this family was examined in normal bronchial epithelial and NSCLC cell lines. Furthermore, the effect of IL-20 on VEGF family members was examined. The expression of IL-20 and its receptors are frequently dysregulated in NSCLC. IL-20RB mRNA was significantly elevated in NSCLC tumours (p<0.01). Protein levels of the receptors, IL-20RB and IL-22R1, were significantly increased (p<0.01) in the tumours of NSCLC patients. IL-20 and its receptors were found to be epigenetically regulated through histone post-translational modifications and DNA CpG residue methylation. In addition, treatment with recombinant IL-20 resulted in decreased expression of the VEGF family members at the mRNA level. This family of genes are dysregulated in NSCLC and are subject to epigenetic regulation. Whilst the anti-angiogenic properties of IL-20 require further clarification, targeting this family via epigenetic means may be a viable therapeutic option in lung cancer treatment. Copyright © 2011 Elsevier Ltd. All rights reserved.

  11. Telomerase as an Androgen Receptor-Regulated Target in Selenium Chemoprevention of Prostate Cancer

    DTIC Science & Technology

    2010-05-01

    TITLE: Telomerase as an Androgen Receptor-Regulated Target in Selenium Chemoprevention of Prostate Cancer PRINCIPAL INVESTIGATOR...May 2009 - 30 Apr 2010 4. TITLE AND SUBTITLE Telomerase as an Androgen Receptor-Regulated Target in Selenium Chemoprevention of Prostate Cancer...telomerase as a potential target of AR signaling suppression by selenium . We found that combination of selenium and bicalutamide produced a robust down

  12. Role of Adrenal Glucocorticoid Signaling in Prefrontal Cortex Gene Expression and Acute Behavioral Responses to Ethanol

    PubMed Central

    Costin, Blair N.; Wolen, Aaron R.; Fitting, Sylvia; Shelton, Keith L.; Miles, Michael F.

    2012-01-01

    Background Glucocorticoid hormones modulate acute and chronic behavioral and molecular responses to drugs of abuse including psychostimulants and opioids. There is growing evidence that glucocorticoids might also modulate behavioral responses to ethanol. Acute ethanol activates the HPA axis, causing release of adrenal glucocorticoid hormones. Our prior genomic studies suggest glucocorticoids play a role in regulating gene expression in the prefrontal cortex (PFC) of DBA2/J (D2) mice following acute ethanol administration. However, few studies have analyzed the role of glucocorticoid signaling in behavioral responses to acute ethanol. Such work could be significant, given the predictive value for level of response to acute ethanol in the risk for alcoholism. Methods We studied whether the glucocorticoid receptor (GR) antagonist, RU-486, or adrenalectomy (ADX) altered male D2 mouse behavioral responses to acute (locomotor activation, anxiolysis or loss-of-righting reflex (LORR)) or repeated (sensitization) ethanol treatment. Whole genome microarray analysis and bioinformatics approaches were used to identify PFC candidate genes possibly responsible for altered behavioral responses to ethanol following ADX. Results ADX and RU-486 both impaired acute ethanol (2 g/kg) induced locomotor activation in D2 mice without affecting basal locomotor activity. However, neither ADX nor RU-486 altered initiation of ethanol sensitization (locomotor activation or jump counts), ethanol-induced anxiolysis or LORR. ADX mice showed microarray gene expression changes in PFC that significantly overlapped with acute ethanol-responsive gene sets derived by our prior microarray studies. Q-rtPCR analysis verified that ADX decreased PFC expression of Fkbp5 while significantly increasing Gpr6 expression. In addition, high dose RU-486 pre-treatment blunted ethanol-induced Fkbp5 expression. Conclusions Our studies suggest that ethanol’s activation of adrenal glucocorticoid release and subsequent

  13. Epigenetic modification of the oxytocin and glucocorticoid receptor genes is linked to attachment avoidance in young adults.

    PubMed

    Ein-Dor, Tsachi; Verbeke, Willem J M I; Mokry, Michal; Vrtička, Pascal

    2018-08-01

    Attachment in the context of intimate pair bonds is most frequently studied in terms of the universal strategy to draw near, or away, from significant others at moments of personal distress. However, important interindividual differences in the quality of attachment exist, usually captured through secure versus insecure - anxious and/or avoidant - attachment orientations. Since Bowlby's pioneering writings on the theory of attachment, it has been assumed that attachment orientations are influenced by both genetic and social factors - what we would today describe and measure as gene by environment interaction mediated by epigenetic DNA modification - but research in humans on this topic remains extremely limited. We for the first time examined relations between intra-individual differences in attachment and epigenetic modification of the oxytocin receptor (OXTR) and glucocorticoid receptor (NR3C1) gene promoter in 109 young adult human participants. Our results revealed that attachment avoidance was significantly and specifically associated with increased OXTR and NR3C1 promoter methylation. These findings offer first tentative clues on the possible etiology of attachment avoidance in humans by showing epigenetic modification in genes related to both social stress regulation and HPA axis functioning.

  14. Comparison of progesterone and glucocorticoid receptor binding and stimulation of gene expression by progesterone, 17-alpha hydroxyprogesterone caproate (17-OHPC), and related progestins

    PubMed Central

    Attardi, Barbara J.; Zeleznik, Anthony; Simhan, Hyagriv; Chiao, Jye Ping; Mattison, Donald R; Caritis, Steve N

    2007-01-01

    Condensation 17-hydroxyprogesterone caproate is not better than progesterone in binding to progesterone or glucocorticoid receptors or eliciting gene expression in progesterone responsive genes. Comparison of progesterone and glucocorticoid receptor binding and stimulation of gene expression by progesterone, 17-alpha hydroxyprogesterone caproate (17-OHPC), and related progestins. Objective To determine whether the reduction in premature birth attributable to 17-OHPC occurs because of a greater affinity for progesterone (PR) or glucocorticoid (GR) receptors or by enhanced stimulation of progestogen responsive genes when compared with progesterone. Study Design We performed competitive steroid hormone receptor binding assays using cytosols expressing either recombinant human PR-A (rhPR-A) or B (rhPR-B) or rabbit uterine or thymic cytosols. We used four different carcinoma cell lines to assess transactivation of reporter genes or induction of alkaline phosphatase. Results Relative binding affinity of 17-OHPC for rhPR-B, rhPR-A and rabbit PR was 26–30% that of progesterone. Binding of progesterone to rabbit thymic GR was weak. 17-OHPC was comparable to progesterone in eliciting gene expression in all cell lines studied. Conclusions Binding to PR, GR or expression of progesterone-responsive genes is no greater with 17-OHPC than with progesterone. Other mechanisms must account for the beneficial effect of 17-OHPC on preterm birth rates. PMID:18060946

  15. A hotspot in the glucocorticoid receptor DNA-binding domain susceptible to loss of function mutation

    PubMed Central

    Banuelos, Jesus; Shin, Soon Cheon; Lu, Nick Z.

    2015-01-01

    Glucocorticoids (GCs) are used to treat a variety of inflammatory disorders and certain cancers. However, GC resistance occurs in subsets of patients. We found that EL4 cells, a GC-resistant mouse thymoma cell line, harbored a point mutation in their GC receptor (GR) gene, resulting in the substitution of arginine 493 by a cysteine in the second zinc finger of the DNA-binding domain. Allelic discrimination analyses revealed that the R493C mutation occurred on both alleles. In the absence of GCs, the GR in EL4 cells localized predominantly in the cytoplasm and upon dexamethasone treatment underwent nuclear translocation, suggesting the ligand binding ability of the GR in EL4 cells was intact. In transient transfection assays, the R493C mutant could not transactivate the MMTV-luciferase reporter. Site-directed mutagenesis to revert the R493C mutation restored the transactivation activity. Cotransfection experiments showed that the R493C mutant did not inhibit the transcriptional activities of the wild-type GR. In addition, the R493C mutant did not repress either the AP-1 or NF-κB reporters as effectively as WT GR. Furthermore, stable expression of the WT GR in the EL4 cells enabled GC-mediated gene regulation, specifically upregulation of IκBα and downregulation of interferon γ and interleukin 17A. Arginine 493 is conserved among multiple species and all human nuclear receptors and its mutation has also been found in the human GR, androgen receptor, and mineralocorticoid receptor. Thus, R493 is necessary for the transcriptional activity of the GR and a hotspot for mutations that result in GC resistance. PMID:25676786

  16. microRNA-379 couples glucocorticoid hormones to dysfunctional lipid homeostasis

    PubMed Central

    de Guia, Roldan M; Rose, Adam J; Sommerfeld, Anke; Seibert, Oksana; Strzoda, Daniela; Zota, Annika; Feuchter, Yvonne; Krones-Herzig, Anja; Sijmonsma, Tjeerd; Kirilov, Milen; Sticht, Carsten; Gretz, Norbert; Dallinga-Thie, Geesje; Diederichs, Sven; Klöting, Nora; Blüher, Matthias; Berriel Diaz, Mauricio; Herzig, Stephan

    2015-01-01

    In mammals, glucocorticoids (GCs) and their intracellular receptor, the glucocorticoid receptor (GR), represent critical checkpoints in the endocrine control of energy homeostasis. Indeed, aberrant GC action is linked to severe metabolic stress conditions as seen in Cushing's syndrome, GC therapy and certain components of the Metabolic Syndrome, including obesity and insulin resistance. Here, we identify the hepatic induction of the mammalian conserved microRNA (miR)-379/410 genomic cluster as a key component of GC/GR-driven metabolic dysfunction. Particularly, miR-379 was up-regulated in mouse models of hyperglucocorticoidemia and obesity as well as human liver in a GC/GR-dependent manner. Hepatocyte-specific silencing of miR-379 substantially reduced circulating very-low-density lipoprotein (VLDL)-associated triglyceride (TG) levels in healthy mice and normalized aberrant lipid profiles in metabolically challenged animals, mediated through miR-379 effects on key receptors in hepatic TG re-uptake. As hepatic miR-379 levels were also correlated with GC and TG levels in human obese patients, the identification of a GC/GR-controlled miRNA cluster not only defines a novel layer of hormone-dependent metabolic control but also paves the way to alternative miRNA-based therapeutic approaches in metabolic dysfunction. PMID:25510864

  17. Neuromodulatory propensity of Bacopa monniera against scopolamine-induced cytotoxicity in PC12 cells via down-regulation of AChE and up-regulation of BDNF and muscarnic-1 receptor expression.

    PubMed

    Pandareesh, M D; Anand, T

    2013-10-01

    Scopolamine is a competitive antagonist of muscarinic acetylcholine receptors, and thus classified as an anti-muscarinic and anti-cholinergic drug. PC12 cell lines possess muscarinic receptors and mimic the neuronal cells. These cells were treated with different concentrations of scopolamine for 24 h and were protected from the cellular damage by pretreatment with Bacopa monniera extract (BME). In current study, we have explored the molecular mechanism of neuromodulatory and antioxidant propensity of (BME) to attenuate scopolamine-induced cytotoxicity using PC12 cells. Our results elucidate that pretreatment of PC12 cells with BME ameliorates the mitochondrial and plasma membrane damage induced by 3 μg/ml scopolamine to 54.83 and 30.30 % as evidenced by MTT and lactate dehydrogenase assays respectively. BME (100 μg/ml) ameliorated scopolamine effect by down-regulating acetylcholine esterase and up-regulating brain-derived neurotropic factor and muscarinic muscarinic-1 receptor expression. BME pretreated cells also showed significant protection against scopolamine-induced toxicity by restoring the levels of antioxidant enzymes and lipid peroxidation. This result indicates that the scopolamine-induced cytotoxicity and neuromodulatory changes were restored with the pretreatment of BME.

  18. Toll-like receptor 4 protects against stress-induced ulcers via regulation of glucocorticoid production in mice.

    PubMed

    Wang, Liang; Luo, Pengfei; Zhang, Fang; Zhang, Yuelu; Wang, Xingtong; Chang, Fei; Zhang, Yuechan; Tang, Hongtai; Xia, Zhaofan

    2017-01-01

    Stress-induced gastric ulcer is an important life-threatening condition, while the molecular basis of its development is incompletely understood. Toll-like receptor 4 (TLR4), an innate immune pattern recognition receptor, can induce pro-inflammatory transcription, aggravating a stress ulcer. The present study found that TLR4 played a protective role in a mouse model of water immersion (23 °C) restraint stress. Wild-type (WT) and TLR4 -/- male mice were respectively divided into five groups (5 per group), and exposed to the stressor for 0, 0.5, 1, 2, or 4 hours. Gastric ulcer index, determined post mortem, increased with time in both types of mice but was greater in TLR4 -/- mice. Furthermore, increased serum cortisol and corticosterone concentrations were observed in WT mice only, and such increases were detected only in WT mice 4 h after lipopolysaccharide (LPS) treatment (2 mg/kg, intraperitoneal injection). Moreover, the administration of cortisol alleviated the gastric injury in TLR4 -/- mice. Western blotting showed expression in the adrenal of P450scc (CYP11A1), the first rate-limiting enzyme in the synthesis of steroids, was increased 4 h after water immersion restraint stress or LPS treatment in WT mice, but was conversely decreased in TLR4 -/- mice after either stressor. Furthermore, in adrenal glands of TLR4 -/- mice, structural distortion of mitochondria (which contain CYP11A1) was found with electron microscopy, and lack of lipid-storing droplets was found using light microscopy on adrenal cryosections stained with Oil red O. These data indicate that TLR4 plays a protective role in stress-induced gastric ulcer that is exerted via impacting synthesis of glucocorticoid in the adrenal gland.

  19. 9β Polymorphism of the Glucocorticoid Receptor Gene Appears to Have Limited Impact in Patients with Addison’s Disease

    PubMed Central

    Ross, Ian Louis; Dandara, Collet; Swart, Marelize; Lacerda, Miguel; Schatz, Desmond; Blom, Dirk Jacobus

    2014-01-01

    Background Addison’s disease (AD) has been associated with an increased risk of cardiovascular disease. Glucocorticoid receptor polymorphisms that alter glucocorticoid sensitivity may influence metabolic and cardiovascular risk factors in patients with AD. The 9β polymorphism of the glucocorticoid receptor gene is associated with relative glucocorticoid resistance and has been reported to increase the risk of myocardial infarction in the elderly. We explored the impact of this polymorphism in patients with AD. Materials and Methods 147 patients with AD and 147 age, gender and ethnicity matched healthy controls were recruited. Blood was taken in a non-fasted state for plasma lipid determination, measurement of cardiovascular risk factors and DNA extraction. Results Genotype data for the 9β polymorphism was available for 139 patients and 146 controls. AD patients had a more atherogenic lipid profile characterized by an increase in the prevalence of small dense LDL (p = 0.003), increased triglycerides (p = 0.002), reduced HDLC (p<0.001) an elevated highly sensitive C-reactive protein (p = 0.01), compared with controls. The 9β polymorphism (at least one G allele) was found in 28% of patients and controls respectively. After adjusting for age, gender, ethnicity, BMI and hydrocortisone dose per metre square of body surface area in patients, there were no significant metabolic associations with this polymorphism and hydrocortisone doses were not higher in patients with the polymorphism. Conclusions This study did not identify any associations between the 9β polymorphism and cardiovascular risk factors or hydrocortisone dose and determination of this polymorphism is therefore unlikely to be of clinical benefit in the management of patients with AD. PMID:24466047

  20. Genetic variation in the glucocorticoid receptor and psychopathology after dexamethasone administration in cardiac surgery patients.

    PubMed

    Kok, Lotte; Hillegers, Manon H; Veldhuijzen, Dieuwke S; Boks, Marco Pm; Dieleman, Jan M; van Dijk, Diederik; Joëls, Marian; Vinkers, Christiaan H

    2018-08-01

    The glucocorticoid receptor (GR) agonist dexamethasone is frequently used for its anti-inflammatory properties. We recently showed that a single high-dose of dexamethasone had long-lasting protective effects on the development of psychopathology after cardiac surgery and postoperative intensive care unit stay. In this study, we investigated whether common genetic variation in the hypothalamic-pituitary-adrenal (HPA)-axis would influence the susceptibility for PTSD and depression after dexamethasone administration. Participants (n = 996) of the Dexamethasone for Cardiac Surgery (DECS) randomized clinical trial were followed after receiving a single high intraoperative dose of dexamethasone (1 mg/kg), a GR agonist, or placebo. PTSD and depressive symptoms were assessed up to four years after cardiac surgery. We focused primarily on five common single nucleotide polymorphisms (SNPs) in the glucocorticoid receptor (GR). Secondarily, we comprehensively assessed common genetic variation in the FK506 binding protein (FKBP5) and the mineralocorticoid receptor (MR). The protective effects of dexamethasone on postoperative PTSD symptoms were dependent on the GR polymorphisms rs41423247 (p = .009), rs10052957 (p = .003), and rs6189 (p = .002), but not on rs6195 (p = .025) or rs6198, (p = .026) after Bonferroni correction. No genotype-dependent effects were found for postoperative depressive symptoms. Also, no associations of FKBP5 and MR polymorphisms were found on PTSD and depression outcomes. Protective effects of dexamethasone on PTSD symptoms after cardiac surgery and ICU stay seem to depend on common genetic variation in its target receptor, the GR. These effects indicate that pre-operative genetic screening could potentially help in stratifying patients for their vulnerability for developing PTSD symptoms after surgery. Copyright © 2018. Published by Elsevier Ltd.

  1. Memory consolidation in human sleep depends on inhibition of glucocorticoid release.

    PubMed

    Plihal, W; Born, J

    1999-09-09

    Early sleep dominated by slow-wave sleep has been found to be particularly relevant for declarative memory formation via hippocampo-neocortical networks. Concurrently, early nocturnal sleep is characterized by an inhibition of glucocorticoid release from the adrenals. Here, we show in healthy humans that this inhibition serves to support declarative memory consolidation during sleep. Elevating plasma glucocorticoid concentration during early sleep by administration of cortisol impaired consolidation of paired associate words, but not of non-declarative memory of visuomotor skills. Since glucocorticoid concentration was enhanced only during retention sleep, but not during acquisition or retrieval, a specific effect on the consolidation process is indicated. Blocking mineralocorticoid receptors by canrenoate did not affect memory, suggesting inactivation of glucocorticoid receptors to be the essential prerequisite for memory consolidation during early sleep.

  2. Mouse glucocorticoid-induced tumor necrosis factor receptor ligand is costimulatory for T cells

    PubMed Central

    Tone, Masahide; Tone, Yukiko; Adams, Elizabeth; Yates, Stephen F.; Frewin, Mark R.; Cobbold, Stephen P.; Waldmann, Herman

    2003-01-01

    Recently, agonist antibodies to glucocorticoid-induced tumor necrosis factor receptor (GITR) (tumor necrosis factor receptor superfamily 18) have been shown to neutralize the suppressive activity of CD4+CD25+ regulatory T cells. It was anticipated that this would be the role of the physiological ligand. We have identified and expressed the gene for mouse GITR ligand and have confirmed that its interaction with GITR reverses suppression by CD4+CD25+ T cells. It also, however, provides a costimulatory signal for the antigen-driven proliferation of naïve T cells and polarized T helper 1 and T helper 2 clones. RT-PCR and mAb staining revealed mouse GITR ligand expression in dendritic cells, macrophages, and B cells. Expression was controlled by the transcription factor NF-1 and potentially by alternative splicing of mRNA destabilization sequences. PMID:14608036

  3. In vitro and in silico assessment of the structure-dependent binding of bisphenol analogues to glucocorticoid receptor.

    PubMed

    Zhang, Jie; Zhang, Tiehua; Guan, Tianzhu; Yu, Hansong; Li, Tiezhu

    2017-03-01

    Widespread use of bisphenol A (BPA) and other bisphenol analogues has attracted increasing attention for their potential adverse effects. As environmental endocrine-disrupting compounds (EDCs), bisphenols (BPs) may activate a variety of nuclear receptors, including glucocorticoid receptor (GR). In this work, the binding of 11 BPs to GR was investigated by fluorescence polarization (FP) assay in combination with molecular dynamics simulations. The human glucocorticoid receptor was prepared as a soluble recombinant protein. A fluorescein-labeled dexamethasone derivative (Dex-fl) was employed as tracer. Competitive displacement of Dex-fl from GR by BPs showed that the binding affinities of bisphenol analogues were largely dependent on their characteristic functional groups. In order to further understand the relationship between BPs structures and their GR-mediated activities, molecular docking was utilized to explore the binding modes at the atomic level. The results confirmed that structural variations of bisphenol analogues contributed to different interactions of BPs with GR, potentially causing distinct toxic effects. Comparison of the calculated binding energies vs. experimental binding affinities yielded a good correlation (R 2  = 0.8266), which might be helpful for the design of environmentally benign materials with reduced toxicities. In addition, the established FP assay based on GR exhibited the potential to offer an alternative to traditional methods for the detection of bisphenols.

  4. Thymic involution in the suspended rat - Adrenal hypertrophy and glucocorticoid receptor content

    NASA Technical Reports Server (NTRS)

    Steffen, J. M.; Musacchia, X. J.

    1986-01-01

    The relationship between thymic involution and adrenal hypertrophy is studied. The thymus, adrenal glands, and tissue water content are evaluated in male Sprague rats suspended in antiorthostatic (AO) or orthostatic (O) positions. A 50 percent decrease in the wet weight of the thymus and hypertrophy of the adrenal glands are observed during the seven days of AO suspension. After seven days of recovery the thymus weight is increased to control level; however, the hypertrophy of the adrenal glands remains unchanged. Thymic and renal responses in O postioned rats are similar to AO reactions. Thymic glucocorticoid (GC) receptor concentrations in the rats are analyzed; a 20 percent decrease in GC receptor site concentration, which is related to thymic involution, is detected in both AO and O rats. It is concluded that there is a temporal correlation between thymic involution and adrenal hypertrophy, which is not affected by AO positioning, and thymic involution is not associated with an increased sensitivity to GC.

  5. Hepatic growth hormone and glucocorticoid receptor signaling in body growth, steatosis and metabolic liver cancer development

    PubMed Central

    Mueller, Kristina M.; Themanns, Madeleine; Friedbichler, Katrin; Kornfeld, Jan-Wilhelm; Esterbauer, Harald; Tuckermann, Jan P.; Moriggl, Richard

    2012-01-01

    Growth hormone (GH) and glucocorticoids (GCs) are involved in the control of processes that are essential for the maintenance of vital body functions including energy supply and growth control. GH and GCs have been well characterized to regulate systemic energy homeostasis, particular during certain conditions of physical stress. However, dysfunctional signaling in both pathways is linked to various metabolic disorders associated with aberrant carbohydrate and lipid metabolism. In liver, GH-dependent activation of the transcription factor signal transducer and activator of transcription (STAT) 5 controls a variety of physiologic functions within hepatocytes. Similarly, GCs, through activation of the glucocorticoid receptor (GR), influence many important liver functions such as gluconeogenesis. Studies in hepatic Stat5 or GR knockout mice have revealed that they similarly control liver function on their target gene level and indeed, the GR functions often as a cofactor of STAT5 for GH-induced genes. Gene sets, which require physical STAT5–GR interaction, include those controlling body growth and maturation. More recently, it has become evident that impairment of GH-STAT5 signaling in different experimental models correlates with metabolic liver disease, ranging from hepatic steatosis to hepatocellular carcinoma (HCC). While GH-activated STAT5 has a protective role in chronic liver disease, experimental disruption of GC-GR signaling rather seems to ameliorate metabolic disorders under metabolic challenge. In this review, we focus on the current knowledge about hepatic GH-STAT5 and GC-GR signaling in body growth, metabolism, and protection from fatty liver disease and HCC development. PMID:22564914

  6. Leucine Stimulates Insulin Secretion via Down-regulation of Surface Expression of Adrenergic α2A Receptor through the mTOR (Mammalian Target of Rapamycin) Pathway

    PubMed Central

    Yang, Jun; Dolinger, Michael; Ritaccio, Gabrielle; Mazurkiewicz, Joseph; Conti, David; Zhu, Xinjun; Huang, Yunfei

    2012-01-01

    The amino acid leucine is a potent secretagogue, capable of inducing insulin secretion. It also plays an important role in the regulation of mTOR activity, therefore, providing impetus to investigate if a leucine-sensing mechanism in the mTOR pathway is involved in insulin secretion. We found that leucine-induced insulin secretion was inhibited by both the mTOR inhibitor rapamycin as well as the adrenergic α2 receptor agonist clonidine. We also demonstrated that leucine down-regulated the surface expression of adrenergic α2A receptor via activation of the mTOR pathway. The leucine stimulatory effect on insulin secretion was attenuated in diabetic Goto-Kakizaki rats that overexpress adrenergic α2A receptors, confirming the role of leucine in insulin secretion. Thus, our data demonstrate that leucine regulates insulin secretion by modulating adrenergic α2 receptors through the mTOR pathway. The role of the mTOR pathway in metabolic homeostasis led us to a second important finding in this study; retrospective analysis of clinical data showed that co-administration of rapamycin and clonidine was associated with an increased incidence of new-onset diabetes in renal transplantation patients over those receiving rapamycin alone. We believe that inhibition of mTOR by rapamycin along with activation of adrenergic α2 receptors by clonidine represents a double-hit to pancreatic islets that synergistically disturbs glucose homeostasis. This new insight may have important implications for the clinical management of renal transplant patients. PMID:22645144

  7. Overexpression of rice LRK1 restricts internode elongation by down-regulating OsKO2.

    PubMed

    Yang, Mengfei; Qi, Weiwei; Sun, Fan; Zha, Xiaojun; Chen, Mingluan; Huang, Yunqing; Feng, Yu-Qi; Yang, Jinshui; Luo, Xiaojin

    2013-01-01

    Rice (Oryza sativa) has the potential to undergo rapid internodal elongation which determines plant height. Gibberellin is involved in internode elongation. Leucine-rich repeat receptor-like kinases (LRR-RLKs) are the largest subfamily of transmembrane receptor-like kinases in plants. LRR-RLKs play important functions in mediating a variety of cellular processes and regulating responses to environmental signals. LRK1, a PSK receptor homolog, is a member of the LRR-RLK family. In the present study, differences in ectopic expression of LRK1 were consistent with extent of rice internode elongation. Analyses of gene expression demonstrated that LRK1 restricts gibberellin biosynthesis during the internode elongation process by down-regulation of the gibberellin biosynthetic gene coding for ent-kaurene oxidase.

  8. IL-10 down-regulates T cell activation by antigen-presenting liver sinusoidal endothelial cells through decreased antigen uptake via the mannose receptor and lowered surface expression of accessory molecules.

    PubMed

    Knolle, P A; Uhrig, A; Hegenbarth, S; Löser, E; Schmitt, E; Gerken, G; Lohse, A W

    1998-12-01

    Our study demonstrates that antigen-presenting liver sinusoidal endothelial cells (LSEC) induce production of interferon-gamma (IFN-gamma) from cloned Th1 CD4+ T cells. We show that LSEC used the mannose receptor for antigen uptake, which further strengthened the role of LSEC as antigen-presenting cell (APC) population in the liver. The ability of LSEC to activate cloned CD4+ T cells antigen-specifically was down-regulated by exogenous prostaglandin E2 (PGE2) and by IL-10. We identify two separate mechanisms by which IL-10 down-regulated T cell activation through LSEC. IL-10 decreased the constitutive surface expression of MHC class II as well as of the accessory molecules CD80 and CD86 on LSEC. Furthermore, IL-10 diminished mannose receptor activity in LSEC. Decreased antigen uptake via the mannose receptor and decreased expression of accessory molecules may explain the down-regulation of T cell activation through IL-10. Importantly, the expression of low numbers of antigen on MHC II in the absence of accessory signals on LSEC may lead to induction of anergy in T cells. Because PGE2 and IL-10 are released from LSEC or Kupffer cells (KC) in response to those concentrations of endotoxin found physiologically in portal venous blood, it is possible that the continuous presence of these mediators and their negative effect on the local APC may explain the inability of the liver to induce T cell activation and to clear chronic infections. Our results support the notion that antigen presentation by LSEC in the hepatic microenvironment contributes to the observed inability to mount an effective cell-mediated immune response in the liver.

  9. Glucocorticoids, epigenetic control and stress resilience

    PubMed Central

    Reul, Johannes M.H.M.; Collins, Andrew; Saliba, Richard S.; Mifsud, Karen R.; Carter, Sylvia D.; Gutierrez-Mecinas, Maria; Qian, Xiaoxiao; Linthorst, Astrid C.E.

    2014-01-01

    Glucocorticoid hormones play a pivotal role in the response to stressful challenges. The surge in glucocorticoid hormone secretion after stress needs to be tightly controlled with characteristics like peak height, curvature and duration depending on the nature and severity of the challenge. This is important as chronic hyper- or hypo-responses are detrimental to health due to increasing the risk for developing a stress-related mental disorder. Proper glucocorticoid responses to stress are critical for adaptation. Therefore, the tight control of baseline and stress-evoked glucocorticoid secretion are important constituents of an organism's resilience. Here, we address a number of mechanisms that illustrate the multitude and complexity of measures safeguarding the control of glucocorticoid function. These mechanisms include the control of mineralocorticoid (MR) and glucocorticoid receptor (GR) occupancy and concentration, the dynamic control of free glucocorticoid hormone availability by corticosteroid-binding globulin (CBG), and the control exerted by glucocorticoids at the signaling, epigenetic and genomic level on gene transcriptional responses to stress. We review the beneficial effects of regular exercise on HPA axis and sleep physiology, and cognitive and anxiety-related behavior. Furthermore, we describe that, possibly through changes in the GABAergic system, exercise reduces the impact of stress on a signaling pathway specifically in the dentate gyrus that is strongly implicated in the behavioral response to that stressor. These observations underline the impact of life style on stress resilience. Finally, we address how single nucleotide polymorphisms (SNPs) affecting glucocorticoid action can compromise stress resilience, which becomes most apparent under conditions of childhood abuse. PMID:27589660

  10. Vasopressin and angiotensin II in reflex regulation of ACTH, glucocorticoids, and renin: effect of water deprivation

    NASA Technical Reports Server (NTRS)

    Brooks, V. L.; Keil, L. C.

    1992-01-01

    Angiotensin II (ANG II) and vasopressin participate in baroreflex regulation of adrenocorticotropic hormone (ACTH), glucocorticoid, and renin secretion. The purpose of this study was to determine whether this participation is enhanced in water-deprived dogs, with chronically elevated plasma ANG II and vasopressin levels, compared with water-replete dogs. The baroreflex was assessed by infusing increasing doses of nitroprusside (0.3, 0.6, 1.5, and 3.0 micrograms.kg-1.min-1) in both groups of animals. To quantitate the participation of ANG II and vasopressin, the dogs were untreated or pretreated with the competitive ANG II antagonist saralasin, a V1-vasopressin antagonist, or combined V1/V2-vasopressin antagonist, either alone or in combination. The findings were as follows. 1) Larger reflex increases in ANG II, vasopressin, and glucocorticoids, but not ACTH, were produced in water-deprived dogs compared with water-replete dogs. 2) ANG II blockade blunted the glucocorticoid and ACTH responses to hypotension in water-deprived dogs, but not water-replete dogs. In contrast, vasopressin blockade reduced the ACTH response only in water-replete dogs. 3) Vasopressin or combined vasopressin and ANG II blockade reduced the plasma level of glucocorticoids related either to the fall in arterial pressure or to the increase in plasma ACTH concentration in water-replete dogs, and this effect was enhanced in water-deprived dogs. 4) In both water-deprived and water-replete animals, saralasin and/or a V1-antagonist increased the renin response to hypotension, but a combined V1/V2-antagonist did not. These results reemphasize the importance of endogenous ANG II and vasopressin in the regulation of ACTH, glucocorticoid, and renin secretion.(ABSTRACT TRUNCATED AT 250 WORDS).

  11. Aldosterone induces clonal β-cell failure through glucocorticoid receptor

    PubMed Central

    Chen, Fang; Liu, Jia; Wang, Yanyang; Wu, Tijun; Shan, Wei; Zhu, Yunxia; Han, Xiao

    2015-01-01

    Aldosterone excess causes insulin resistance in peripheral tissues and directly impairs the function of clonal β-cell. The aim of this study was to investigate the molecular mechanisms involved in the aldosterone-induced impairment of clonal β-cells. As expected, aldosterone induced apoptosis and β-cell dysfunction, including impairment of insulin synthesis and secretion, which were reversed by Glucocorticoid receptor (GR) antagonists or GR-specific siRNA. However, mineralocorticoid receptor (MR) antagonists or MR-specific siRNA had no effect on impairment of clonal β-cells induced by aldosterone. Besides, aldosterone significantly decreased expression and activity of MafA, while activated JNK and p38 MAPK in a GR-dependent manner. In addition, JNK inhibitors (SP600125) and/or p38 inhibitors (SB203580) could abolish the effect of aldosterone on MafA expression and activity. Importantly, overexpression of JNK1 or p38 reversed the protective effect of a GR antagonist on the decrease of MafA expression and activity. Furthermore, aldosterone inhibits MafA expression at the transcriptional and post-transcriptional level through activation of JNK and p38, respectively. Consequently, overexpression of MafA increased synthesis and secretion of insulin, and decreased apoptosis in clonal β-cells exposed to aldosterone. These findings identified aldosterone as an inducer of clonal β-cell failure that operates through the GR-MAPK-MafA signaling pathway. PMID:26287126

  12. Serum brain-derived neurotrophic factor and glucocorticoid receptor levels in lymphocytes as markers of antidepressant response in major depressive patients: a pilot study.

    PubMed

    Rojas, Paulina Soledad; Fritsch, Rosemarie; Rojas, Romina Andrea; Jara, Pablo; Fiedler, Jenny Lucy

    2011-09-30

    Depressive patients often have altered cortisol secretion, an effect that likely derives from impaired activity of the glucocorticoid receptor (GR), the main regulator of the hypothalamus-pituitary-adrenal (HPA) axis. Glucocorticoids reduce the levels of brain-derived neurotrophic factor (BDNF), a downstream target of antidepressants. Antidepressants promote the transcriptional activity of cyclic adenosine monophosphate (cAMP) response element binding protein (CREB), a regulator of BDNF expression. To identify potential biomarkers for the onset of antidepressant action in depressive patients, GR and phospho-CREB (pCREB) levels in lymphocytes and serum BDNF levels were repeatedly measured during the course of antidepressant treatment. Thirty-four depressed outpatients (10 male and 24 female) were treated with venlafaxine (75mg/day), and individuals exhibiting a 50% reduction in their baseline 17-Item Hamilton Depression Rating Scale score by the 6th week of treatment were considered responders. Responders showed an early improvement in parallel with a rise in BDNF levels during the first two weeks of treatment. Non-responders showed increased GR levels by the third week and reduced serum BDNF by the sixth week of treatment. In contrast, venlafaxine did not affect levels of pCREB. We conclude that levels of BDNF in serum and GR levels in lymphocytes may represent biomarkers that could be used to predict responses to venlafaxine treatment. Copyright © 2011 Elsevier Ltd. All rights reserved.

  13. Glucocorticoids Inhibit Basal and Hormone-Induced Serotonin Synthesis in Pancreatic Beta Cells

    PubMed Central

    Hasni Ebou, Moina; Singh-Estivalet, Amrit; Launay, Jean-Marie; Callebert, Jacques; Tronche, François; Ferré, Pascal; Gautier, Jean-François; Guillemain, Ghislaine; Bréant, Bernadette

    2016-01-01

    Diabetes is a major complication of chronic Glucocorticoids (GCs) treatment. GCs induce insulin resistance and also inhibit insulin secretion from pancreatic beta cells. Yet, a full understanding of this negative regulation remains to be deciphered. In the present study, we investigated whether GCs could inhibit serotonin synthesis in beta cell since this neurotransmitter has been shown to be involved in the regulation of insulin secretion. To this aim, serotonin synthesis was evaluated in vitro after treatment with GCs of either islets from CD1 mice or MIN6 cells, a beta-cell line. We also explored the effect of GCs on the stimulation of serotonin synthesis by several hormones such as prolactin and GLP 1. We finally studied this regulation in islet in two in vivo models: mice treated with GCs and with liraglutide, a GLP1 analog, and mice deleted for the glucocorticoid receptor in the pancreas. We showed in isolated islets and MIN6 cells that GCs decreased expression and activity of the two key enzymes of serotonin synthesis, Tryptophan Hydroxylase 1 (Tph1) and 2 (Tph2), leading to reduced serotonin contents. GCs also blocked the induction of serotonin synthesis by prolactin or by a previously unknown serotonin activator, the GLP-1 analog exendin-4. In vivo, activation of the Glucagon-like-Peptide-1 receptor with liraglutide during 4 weeks increased islet serotonin contents and GCs treatment prevented this increase. Finally, islets from mice deleted for the GR in the pancreas displayed an increased expression of Tph1 and Tph2 and a strong increased serotonin content per islet. In conclusion, our results demonstrate an original inhibition of serotonin synthesis by GCs, both in basal condition and after stimulation by prolactin or activators of the GLP-1 receptor. This regulation may contribute to the deleterious effects of GCs on beta cells. PMID:26901633

  14. Role of Pro-637 and Gln-642 in human glucocorticoid receptors and Ser-843 and Leu-848 in mineralocorticoid receptors in their differential responses to cortisol and aldosterone.

    PubMed

    Mani, Orlando; Nashev, Lyubomir G; Livelo, Christopher; Baker, Michael E; Odermatt, Alex

    2016-05-01

    Mineralocorticoid receptors (MR) and glucocorticoid receptors (GR) are descended from a common ancestral corticoid receptor. The basis for specificities of human MR for aldosterone and human GR for glucocorticoids, such as cortisol, bearing 17α-hydroxyl-groups, is incompletely understood. Differences in MR at S843 and L848 and GR at the corresponding P637 and Q642 have been proposed as important in their different responses to glucocorticoids with 17α-hydroxyl-groups. We investigated the impact of these residues on binding affinity (Ki) and transcriptional activation (EC50) of mutants MR-S843P, MR-L848Q and MR-S843P/L848Q and mutants GR-P637S, GR-Q642L and GR-P637S/Q642L in the presence of different corticosteroids. Aldosterone, cortisol and corticosterone had similar affinities for wild-type MR and all mutants, while dexamethasone had increased affinity for the three mutants. However, transactivation of MR-S843P and MR-S843P/L848Q by all four steroids was significantly lower than for wild-type MR. In contrast, transactivation of MR-L848Q tended to be 3-fold higher for cortisol and corticosterone and increased 7-fold for dexamethasone, indicating that MR-L848Q has an increased response to glucocorticoids, while retaining a strong response to aldosterone. Compared to wild-type GR, GR-P637S and GR-Q642L had increased affinities and significantly increased transcriptional activity with aldosterone and corticosterone, and GR-P637S had similar transcriptional activity with cortisol and dexamethasone, while GR-Q642L and GR-P637S/Q642L had a significant decrease in transcriptional activity with cortisol and dexamethasone. 3D-models of these MR and GR mutants revealed that dexamethasone and aldosterone, respectively, fit nicely into the steroid-binding pocket, consistent with the affinity of dexamethasone for MR mutants and aldosterone for GR mutants. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Neurotrophins and their receptors in the rat pituitary gland: regulation of BDNF and trkB mRNA levels by adrenal hormones.

    PubMed

    Kononen, J; Soinila, S; Persson, H; Honkaniemi, J; Hökfelt, T; Pelto-Huikko, M

    1994-12-01

    We studied the expression of messenger ribonucleic acids (mRNAs) for neurotrophins and neurotrophin receptors in the rat pituitary gland and examined the influence of adrenal hormones on their mRNA levels, using in situ hybridization and Northern blot analysis. The only neurotrophin present at detectable levels in the pituitary was brain-derived neurotrophic factor (BDNF), which was observed in the anterior and intermediate lobes. Several transcripts of the putative receptor for BDNF, trkB, were present in the anterior and posterior lobes of the pituitary. A low amount of trkC mRNA was found in both the anterior and the intermediate lobe. Dexamethasone treatment decreased both BDNF and trkB mRNA levels in the anterior lobe of the pituitary. Adrenalectomy had no effect on trkB expression, but it decreased BDNF mRNA levels in comparison to the control animals. This effect could not be reversed by dexamethasone substitution, suggesting that BDNF, mRNA levels may be regulated not only by glucocorticoids but also by other adrenal hormones. These results demonstrate that BDNF, trkB and trkC are expressed in the pituitary gland and that glucocorticoids and possibly other adrenal hormones may modulate pituitary functions by regulating the expression of neurotrophic factors and their receptors. Whether BDNF acts as a secreted hormone, a trophic factor, or has autocrine/paracrine functions within the pituitary through its receptor, trkB, remains to be studied.

  16. Expression Profiling Identifies Klf15 as a Glucocorticoid Target That Regulates Airway Hyperresponsiveness

    PubMed Central

    Masuno, Kiriko; Haldar, Saptarsi M.; Jeyaraj, Darwin; Mailloux, Christina M.; Huang, Xiaozhu; Panettieri, Rey A.; Jain, Mukesh K.

    2011-01-01

    Glucocorticoids (GCs), which activate GC receptor (GR) signaling and thus modulate gene expression, are widely used to treat asthma. GCs exert their therapeutic effects in part through modulating airway smooth muscle (ASM) structure and function. However, the effects of genes that are regulated by GCs on airway function are not fully understood. We therefore used transcription profiling to study the effects of a potent GC, dexamethasone, on human ASM (HASM) gene expression at 4 and 24 hours. After 24 hours of dexamethasone treatment, nearly 7,500 genes had statistically distinguishable changes in expression; quantitative PCR validation of a 40-gene subset of putative GR-regulated genes in 6 HASM cell lines suggested that the early transcriptional targets of GR signaling are similar in independent HASM lines. Gene ontology analysis implicated GR targets in controlling multiple aspects of ASM function. One GR-regulated gene, the transcription factor, Kruppel-like factor 15 (Klf15), was already known to modulate vascular smooth and cardiac muscle function, but had no known role in the lung. We therefore analyzed the pulmonary phenotype of Klf15−/− mice after ovalbumin sensitization and challenge. We found diminished airway responses to acetylcholine in ovalbumin-challenged Klf15−/− mice without a significant change in the induction of asthmatic inflammation. In cultured cells, overexpression of Klf15 reduced proliferation of HASM cells, whereas apoptosis in Klf15−/− murine ASM cells was increased. Together, these results further characterize the GR-regulated gene network in ASM and establish a novel role for the GR target, Klf15, in modulating airway function. PMID:21257922

  17. Inflammation in Parkinson’s disease: role of glucocorticoids

    PubMed Central

    Herrero, María-Trinidad; Estrada, Cristina; Maatouk, Layal; Vyas, Sheela

    2015-01-01

    Chronic inflammation is a major characteristic feature of Parkinson’s disease (PD). Studies in PD patients show evidence of augmented levels of potent pro-inflammatory molecules e.g., TNF-α, iNOS, IL-1β whereas in experimental Parkinsonism it has been consistently demonstrated that dopaminergic neurons are particularly vulnerable to activated glia releasing these toxic factors. Recent genetic studies point to the role of immune system in the etiology of PD, thus in combination with environmental factors, both peripheral and CNS-mediated immune responses could play important roles in onset and progression of PD. Whereas microglia, astrocytes and infiltrating T cells are known to mediate chronic inflammation, the roles of other immune-competent cells are less well understood. Inflammation is a tightly controlled process. One major effector system of regulation is HPA axis. Glucocorticoids (GCs) released from adrenal glands upon stimulation of HPA axis, in response to either cell injury or presence of pathogen, activate their receptor, GR. GR regulates inflammation both through direct transcriptional action on target genes and by indirectly inhibiting transcriptional activities of transcriptional factors such as NF-κB, AP-1 or interferon regulatory factors. In PD patients, the HPA axis is unbalanced and the cortisol levels are significantly increased, implying a deregulation of GR function in immune cells. In experimental Parkinsonism, the activation of microglial GR has a crucial effect in diminishing microglial cell activation and reducing dopaminergic degeneration. Moreover, GCs are also known to regulate human brain vasculature as well as blood brain barrier (BBB) permeability, any dysfunction in their actions may influence infiltration of cytotoxic molecules resulting in increased vulnerability of dopamine neurons in PD. Overall, deregulation of glucocorticoid receptor actions is likely important in dopamine neuron degeneration through establishment of

  18. 11β-Hydroxysteroid Dehydrogenase Type 1 Regulates Glucocorticoid-Induced Insulin Resistance in Skeletal Muscle

    PubMed Central

    Morgan, Stuart A.; Sherlock, Mark; Gathercole, Laura L.; Lavery, Gareth G.; Lenaghan, Carol; Bujalska, Iwona J.; Laber, David; Yu, Alice; Convey, Gemma; Mayers, Rachel; Hegyi, Krisztina; Sethi, Jaswinder K.; Stewart, Paul M.; Smith, David M.; Tomlinson, Jeremy W.

    2009-01-01

    OBJECTIVE Glucocorticoid excess is characterized by increased adiposity, skeletal myopathy, and insulin resistance, but the precise molecular mechanisms are unknown. Within skeletal muscle, 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) converts cortisone (11-dehydrocorticosterone in rodents) to active cortisol (corticosterone in rodents). We aimed to determine the mechanisms underpinning glucocorticoid-induced insulin resistance in skeletal muscle and indentify how 11β-HSD1 inhibitors improve insulin sensitivity. RESEARCH DESIGN AND METHODS Rodent and human cell cultures, whole-tissue explants, and animal models were used to determine the impact of glucocorticoids and selective 11β-HSD1 inhibition upon insulin signaling and action. RESULTS Dexamethasone decreased insulin-stimulated glucose uptake, decreased IRS1 mRNA and protein expression, and increased inactivating pSer307 insulin receptor substrate (IRS)-1. 11β-HSD1 activity and expression were observed in human and rodent myotubes and muscle explants. Activity was predominantly oxo-reductase, generating active glucocorticoid. A1 (selective 11β-HSD1 inhibitor) abolished enzyme activity and blocked the increase in pSer307 IRS1 and reduction in total IRS1 protein after treatment with 11DHC but not corticosterone. In C57Bl6/J mice, the selective 11β-HSD1 inhibitor, A2, decreased fasting blood glucose levels and improved insulin sensitivity. In KK mice treated with A2, skeletal muscle pSer307 IRS1 decreased and pThr308 Akt/PKB increased. In addition, A2 decreased both lipogenic and lipolytic gene expression. CONCLUSIONS Prereceptor facilitation of glucocorticoid action via 11β-HSD1 increases pSer307 IRS1 and may be crucial in mediating insulin resistance in skeletal muscle. Selective 11β-HSD1 inhibition decreases pSer307 IRS1, increases pThr308 Akt/PKB, and decreases lipogenic and lipolytic gene expression that may represent an important mechanism underpinning their insulin-sensitizing action. PMID

  19. Glucocorticoid receptor haploinsufficiency causes hypertension and attenuates hypothalamic-pituitary-adrenal axis and blood pressure adaptions to high-fat diet

    PubMed Central

    Michailidou, Z.; Carter, R. N.; Marshall, E.; Sutherland, H. G.; Brownstein, D. G.; Owen, E.; Cockett, K.; Kelly, V.; Ramage, L.; Al-Dujaili, E. A. S.; Ross, M.; Maraki, I.; Newton, K.; Holmes, M. C.; Seckl, J. R.; Morton, N. M.; Kenyon, C. J.; Chapman, K. E.

    2008-01-01

    Glucocorticoid hormones are critical to respond and adapt to stress. Genetic variations in the glucocorticoid receptor (GR) gene alter hypothalamic-pituitary-adrenal (HPA) axis activity and associate with hypertension and susceptibility to metabolic disease. Here we test the hypothesis that reduced GR density alters blood pressure and glucose and lipid homeostasis and limits adaption to obesogenic diet. Heterozygous GRβgeo/+ mice were generated from embryonic stem (ES) cells with a gene trap integration of a β-galactosidase-neomycin phosphotransferase (βgeo) cassette into the GR gene creating a transcriptionally inactive GR fusion protein. Although GRβgeo/+ mice have 50% less functional GR, they have normal lipid and glucose homeostasis due to compensatory HPA axis activation but are hypertensive due to activation of the renin-angiotensin-aldosterone system (RAAS). When challenged with a high-fat diet, weight gain, adiposity, and glucose intolerance were similarly increased in control and GRβgeo/+ mice, suggesting preserved control of intermediary metabolism and energy balance. However, whereas a high-fat diet caused HPA activation and increased blood pressure in control mice, these adaptions were attenuated or abolished in GRβgeo/+ mice. Thus, reduced GR density balanced by HPA activation leaves glucocorticoid functions unaffected but mineralocorticoid functions increased, causing hypertension. Importantly, reduced GR limits HPA and blood pressure adaptions to obesogenic diet.—Michailidou, Z., Carter, R. N., Marshall, E., Sutherland, H. G., Brownstein, D. G., Owen, E., Cockett, K., Kelly, V., Ramage, L., Al-Dujaili, E. A. S., Ross, M., Maraki, I., Newton, K., Holmes, M. C., Seckl, J. R., Morton, N. M., Kenyon, C. J., Chapman, K. E. Glucocorticoid receptor haploinsufficiency causes hypertension and attenuates hypothalamic-pituitary-adrenal axis and blood pressure adaptions to high-fat diet. PMID:18697839

  20. Genetics Home Reference: familial glucocorticoid deficiency

    MedlinePlus

    ... familial glucocorticoid deficiency type 1 lead to defective trafficking of the receptor to the cell surface. J ... short stature, and natural killer cell deficiency in humans. J Clin Invest. 2012 Mar;122(3):814- ...

  1. Single prolonged stress enhances hippocampal glucocorticoid receptor and phosphorylated protein kinase B levels

    PubMed Central

    Eagle, Andrew L.; Knox, Dayan; Roberts, Megan M.; Mulo, Kostika; Liberzon, Israel; Galloway, Matthew P.; Perrine, Shane A.

    2012-01-01

    Animal models of posttraumatic stress disorder (PTSD) can explore neurobiological mechanisms by which trauma enhances fear and anxiety reactivity. Single prolonged stress (SPS) shows good validity in producing PTSD-like behavior. While SPS-induced behaviors have been linked to enhanced glucocorticoid receptor (GR) expression, the molecular ramifications of enhanced GR expression have yet to be identified. Phosphorylated protein kinase B (pAkt) is critical for stress-mediated enhancement in general anxiety and memory, and may be regulated by GRs. However, it is currently unknown if pAkt levels are modulated by SPS, as well as if the specificity of GR and pAkt related changes contribute to anxiety-like behavior after SPS. The current study set out to examine the effects of SPS on GR and pAkt protein levels in the amygdala and hippocampus and to examine the specificity of these changes to unconditioned anxiety-like behavior. Levels of GR and pAkt were increased in the hippocampus, but not amygdala. Furthermore, SPS had no effect on unconditioned anxiety-like behavior suggesting that generalized anxiety is not consistently observed following SPS. The results suggest that SPS-enhanced GR expression is associated with phosphorylation of Akt, and also suggest that these changes are not related to an anxiogenic phenotype. PMID:23201176

  2. An N-terminal fragment of substance P, substance P(1-7), down-regulates neurokinin-1 binding in the mouse spinal cord.

    PubMed

    Yukhananov RYu; Larson, A A

    1994-08-29

    Injected intrathecally, substance P (SP) down-regulates neurokinin-1 (NK-1) binding in the spinal cord and desensitizes rats to the behavioral effect of SP. N-terminal fragments of SP, such as SP(1-7), induce antinociception and play a role in desensitization to SP in mice. The goal of this study was to assess the abilities of N- and C-terminal fragments of SP to down-regulate NK-1 binding. Binding of [3H]SP to mouse spinal cord membranes was inhibited by SP, CP-96,345, and to a lesser extent by SP(5-11), but not SP(1-7), consistent with these binding sites being NK-1 receptors. Injection of SP(5-11) intrathecally did not affect the affinity (Kd) or concentration (Bmax) of [3H]SP binding. However, injection of 1 nmol of SP(1-7) decreased the Bmax of [3H]SP binding in the spinal cord at 6 h after its injection just as this dose of SP decreased the Bmax at 24 h. These data suggest that the N-terminus of SP is responsible for down-regulation of NK-1 binding. As SP(5-11) did not down-regulate NK-1 binding, activation of NK-1 sites does not appear necessary or sufficient for down-regulation of SP binding. In contrast, SP(1-7), in spite of its inability to interact with NK-1 sites, did down-regulate SP binding, suggesting an indirect mechanism dissociated from NK-1 receptors.

  3. Differential effects of glucocorticoid and mineralocorticoid antagonism on anxiety behavior in mild traumatic brain injury.

    PubMed

    Fox, Laura C; Davies, Daniel R; Scholl, Jamie L; Watt, Michael J; Forster, Gina L

    2016-10-01

    Mild traumatic brain injuries (TBIs) comprise three-quarters of all TBIs occurring in the United States annually, and psychological symptoms arising from them can last years after injury. One commonly observed symptom following mild TBI is generalized anxiety. Most mild TBIs happen in stressful situations (sports, war, domestic violence, etc.) when glucocorticoids are elevated in the brain at the time of impact, and glucocorticoids have negative effects on neuronal health following TBI. Therefore, blocking glucocorticoid receptors might prevent emergence of anxiety symptoms post-injury. Adult male rats received mifepristone (20mg/kg) or spironolactone (50mg/kg) to block glucocorticoid and mineralocorticoid receptors, respectively, 40min prior to being exposed to acute social defeat stress followed immediately by mild TBI. In defeated rats with concomitant mild TBI, mifepristone restored time spent in the open arms of an elevated plus maze to control levels, demonstrating for the first time that glucocorticoid receptors play a critical role in the development of anxiety after mild TBI. Future treatments could target these receptors, alleviating anxiety as a major side effect in victims of mild TBI sustained in stressful situations. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. Somatostatin increases glucocorticoid binding and signaling in macrophages by blocking the calpain-specific cleavage of Hsp 90.

    PubMed

    Bellocq, A; Doublier, S; Suberville, S; Perez, J; Escoubet, B; Fouqueray, B; Puyol, D R; Baud, L

    1999-12-24

    Somatostatin has direct anti-inflammatory actions and participates in the anti-inflammatory actions of glucocorticoids, but the mechanisms underlying this regulation remain poorly understood. The objective of this study was to evaluate whether somatostatin increases glucocorticoid responsiveness by up-regulating glucocorticoid receptor (GR) expression and signaling. Somatostatin promoted a time- and dose-dependent increase in [(3)H]dexamethasone binding to RAW 264.7 macrophages. Cell exposure to 10 nM somatostatin for 18 h promoted a 2-fold increase in the number of GR sites per cell without significant modification of the affinity. Analysis of GR heterocomplex components demonstrated that somatostatin increased the level of heat shock protein (Hsp) 90, whereas the level of GR remained almost unchanged. The increase in Hsp 90 was associated with a decrease in the cleavage of its carboxyl-terminal domain. Evidence for the involvement of calpain inhibition in this process was obtained by the demonstration that 1) somatostatin induced a dose-dependent decrease in calpain activity and 2) calpain inhibitors, calpain inhibitor I and calpeptin, both abolished the cleavage of Hsp 90 and induced a dose-dependent increase in [(3)H]dexamethasone binding. Increases in glucocorticoid binding after somatostatin treatment were associated with similar increases in the ability of GR to transactivate a minimal promoter containing two glucocorticoid response elements (GRE) and to interfere with the activation of nuclear factor-kappaB (NF-kappaB). Thus, the present findings indicate that somatostatin increases glucocorticoid binding and signaling by limiting the calpain-specific cleavage of GR-associated Hsp 90. This mechanism may represent a novel target for intervention to increase glucocorticoid responsiveness.

  5. Lymphocyte senescence in COPD is associated with loss of glucocorticoid receptor expression by pro-inflammatory/cytotoxic lymphocytes.

    PubMed

    Hodge, Greg; Jersmann, Hubertus; Tran, Hai B; Holmes, Mark; Reynolds, Paul N; Hodge, Sandra

    2015-01-09

    Glucocorticoid (GC) resistance is a major barrier in COPD treatment. We have shown increased expression of the drug efflux pump, Pgp1 in cytotoxic/pro-inflammatory lymphocytes in COPD. Loss of lymphocyte co-stimulatory molecule CD28 (lymphocyte senescence) was associated with a further increase in their pro-inflammatory/cytotoxic potential and resistance to GC. We hypothesized that lymphocyte senescence and increased Pgp1 are also associated with down-regulation of the GC receptor (GCR). Blood was collected from 10 COPD and 10 healthy aged-matched controls. Flow cytometry was applied to assess intracellular pro-inflammatory cytokines, CD28, Pgp1, GCR, steroid binding and relative cytoplasm/nuclear GCR by CD28+ and CD28null T, NKT-like cells. GCR localization was confirmed by fluorescent microscopy. COPD was associated with increased numbers of CD28nullCD8+ T and NKT-like cells. Loss of CD28 was associated with an increased percentage of T and NKT-like cells producing IFNγ or TNFα and associated with a loss of GCR and Dex-Fluor staining but unchanged Pgp1. There was a significant loss of GCR in CD8 + CD28null compared with CD8 + CD28+ T and NKT-like cells from both COPD and controls (eg, mean ± SEM 8 ± 3% GCR + CD8 + CD28null T-cells vs 49 ± 5% GCR + CD8 + CD28+ T-cells in COPD). There was a significant negative correlation between GCR expression and IFNγ and TNFα production by T and NKT-like cells(eg, COPD: T-cell IFNγ R = -.615; ) and with FEV1 in COPD (R = -.777). COPD is associated with loss of GCR in senescent CD28null and NKT-like cells suggesting alternative treatment options to GC are required to inhibit these pro-inflammatory/cytotoxic cells.

  6. Structural Stereochemistry of Androstene Hormones Determines Interactions with Human Androgen, Estrogen, and Glucocorticoid Receptors

    PubMed Central

    Shaak, Thomas L.; Wijesinghe, Dayanjan S.; Chalfant, Charles E.; Diegelmann, Robert F.; Ward, Kevin R.; Loria, Roger M.

    2013-01-01

    DHEA, 17α-AED, 17β-AED, and 17β-AET exhibit strong biological activity that has been attributed to androgenic, estrogenic, or antiglucocorticoid activity in vivo and in vitro. This study compared DHEA, 17α-AED, 17β-AED, and 17β-AET for their ability to activate the human AR, ER, and GR and determine the relative androgenicity, estrogenicity, and glucocorticoid activity. The results show that, at the receptor level, these androstene hormones are weak AR and even weaker ER activators. Direct androstene hormone activation of the human AR, ERα, and ERβ may not be essential for their biological function. Similarly, these hormones indirectly activated the human GR, only in the presence of high dexamethasone concentrations. These results underscore the major difference between androstene hormone interactions with these nuclear receptors and their biological effects. PMID:24729874

  7. Glucocorticoid regulation of a novel HPV-E6-p53-miR-145 pathway modulates invasion and therapy resistance of cervical cancer cells.

    PubMed

    Shi, Ming; Du, Libin; Liu, Dan; Qian, Lu; Hu, Meiru; Yu, Ming; Yang, Zhengyan; Zhao, Mingzhen; Chen, Changguo; Guo, Liang; Wang, Lina; Song, Lun; Ma, Yuanfang; Guo, Ning

    2012-10-01

    Glucocorticoids are stress-responsive neuroendocrine mediators and play an important role in malignant progression, especially in solid tumours. We demonstrate a novel mechanism by which glucocorticoids modulate p53-dependent miR-145 expression in HPV-positive cervical cancer cells through induction of E6 proteins. We found that expression of miR-145 was reduced in cervical cancer tissues. Cortisol induced HPV-E6 expression and suppressed p53 and miR-145 in cervical cancer cells. MiR-145 expression in cervical cancer cells was wild-type p53-dependent, and cortisol-induced down-regulation of miR-145 expression prevented chemotherapy-induced apoptosis, whereas over-expression of miR-145 enhanced sensitivity to mitomycin and reversed the chemoresistance induced by glucocorticoids. We also show that miR-145 augments the effects of p53 by suppressing the inhibitors of p53 in cervical cancer cells, suggesting that miR-145 plays a role in p53 tumour suppression. Finally, we demonstrate that miR-145 inhibits both the motility and invasion of cervical cancer cells. Our findings identify a novel pathway through which the neuroendocrine macroenvironment affects cervical tumour growth, invasion and therapy resistance and show that miR-145 may serve as a target for cervical cancer therapy. Copyright © 2012 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd. Copyright © 2012 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

  8. Nogo receptor 1 regulates formation of lasting memories.

    PubMed

    Karlén, Alexandra; Karlsson, Tobias E; Mattsson, Anna; Lundströmer, Karin; Codeluppi, Simone; Pham, Therese M; Bäckman, Cristina M; Ogren, Sven Ove; Aberg, Elin; Hoffman, Alexander F; Sherling, Michael A; Lupica, Carl R; Hoffer, Barry J; Spenger, Christian; Josephson, Anna; Brené, Stefan; Olson, Lars

    2009-12-01

    Formation of lasting memories is believed to rely on structural alterations at the synaptic level. We had found that increased neuronal activity down-regulates Nogo receptor-1 (NgR1) in brain regions linked to memory formation and storage, and postulated this to be required for formation of lasting memories. We now show that mice with inducible overexpression of NgR1 in forebrain neurons have normal long-term potentiation and normal 24-h memory, but severely impaired month-long memory in both passive avoidance and swim maze tests. Blocking transgene expression normalizes these memory impairments. Nogo, Lingo-1, Troy, endogenous NgR1, and BDNF mRNA expression levels were not altered by transgene expression, suggesting that the impaired ability to form lasting memories is directly coupled to inability to down-regulate NgR1. Regulation of NgR1 may therefore serve as a key regulator of memory consolidation. Understanding the molecular underpinnings of synaptic rearrangements that carry lasting memories may facilitate development of treatments for memory dysfunction.

  9. Nogo receptor 1 regulates formation of lasting memories

    PubMed Central

    Karlén, Alexandra; Karlsson, Tobias E.; Mattsson, Anna; Lundströmer, Karin; Codeluppi, Simone; Pham, Therese M.; Bäckman, Cristina M.; Ögren, Sven Ove; Åberg, Elin; Hoffman, Alexander F.; Sherling, Michael A.; Lupica, Carl R.; Hoffer, Barry J.; Spenger, Christian; Josephson, Anna; Brené, Stefan; Olson, Lars

    2009-01-01

    Formation of lasting memories is believed to rely on structural alterations at the synaptic level. We had found that increased neuronal activity down-regulates Nogo receptor-1 (NgR1) in brain regions linked to memory formation and storage, and postulated this to be required for formation of lasting memories. We now show that mice with inducible overexpression of NgR1 in forebrain neurons have normal long-term potentiation and normal 24-h memory, but severely impaired month-long memory in both passive avoidance and swim maze tests. Blocking transgene expression normalizes these memory impairments. Nogo, Lingo-1, Troy, endogenous NgR1, and BDNF mRNA expression levels were not altered by transgene expression, suggesting that the impaired ability to form lasting memories is directly coupled to inability to down-regulate NgR1. Regulation of NgR1 may therefore serve as a key regulator of memory consolidation. Understanding the molecular underpinnings of synaptic rearrangements that carry lasting memories may facilitate development of treatments for memory dysfunction. PMID:19915139

  10. Deletion of the COOH-Terminal Domain of CXC Chemokine Receptor 4 Leads to the Down-regulation of Cell-to-Cell Contact, Enhanced Motility and Proliferation in Breast Carcinoma Cells

    PubMed Central

    Ueda, Yukiko; Neel, Nicole F.; Schutyser, Evemie; Raman, Dayanidhi; Richmond, Ann

    2009-01-01

    The CXC chemokine receptor 4 (CXCR4) contributes to the metastasis of human breast cancer cells. The CXCR4 COOH-terminal domain (CTD) seems to play a major role in regulating receptor desensitization and down-regulation. We expressed either wild-type CXCR4 (CXCR4-WT) or CTD-truncated CXCR4 (CXCR4-ΔCTD) in MCF-7 human mammary carcinoma cells to determine whether the CTD is involved in CXCR4-modulated proliferation of mammary carcinoma cells. CXCR4-WT-transduced MCF-7 cells (MCF-7/CXCR4-WT cells) do not differ from vector-transduced MCF-7 control cells in morphology or growth rate. However, CXCR4-ΔCTD-transduced MCF-7 cells (MCF-7/CXCR4-ΔCTD cells) exhibit a higher growth rate and altered morphology, potentially indicating an epithelial-to-mesenchymal transition. Furthermore, extracellular signal-regulated kinase (ERK) activation and cell motility are increased in these cells. Ligand induces receptor association with β-arrestin for both CXCR4-WT and CXCR4-ΔCTD in these MCF-7 cells. Overexpressed CXCR4-WT localizes predominantly to the cell surface in unstimulated cells, whereas a significant portion of overexpressed CXCR4-ΔCTD resides intracellularly in recycling endosomes. Analysis with human oligomicroarray, Western blot, and immunohistochemistry showed that E-cadherin and Zonula occludens are down-regulated in MCF-7/CXCR4-ΔCTD cells. The array analysis also indicates that mesenchymal marker proteins and certain growth factor receptors are up-regulated in MCF-7/CXCR4-ΔCTD cells. These observations suggest that (a) the overexpression of CXCR4-ΔCTD leads to a gain-of-function of CXCR4-mediated signaling and (b) the CTD of CXCR4-WT may perform a feedback repressor function in this signaling pathway. These data will contribute to our understanding of how CXCR4-ΔCTD may promote progression of breast tumors to metastatic lesions. PMID:16740704

  11. Enduring, Handling-Evoked Enhancement of Hippocampal Memory Function and Glucocorticoid Receptor Expression Involves Activation of the Corticotropin-Releasing Factor Type 1 Receptor

    PubMed Central

    Fenoglio, Kristina A.; Brunson, Kristen L.; Avishai-Eliner, Sarit; Stone, Blake A.; Kapadia, Bhumika J.; Baram, Tallie Z.

    2011-01-01

    Early-life experience, including maternal care, influences hippocampus-dependent learning and memory throughout life. Handling of pups during postnatal d 2–9 (P2–9) stimulates maternal care and leads to improved memory function and stress-coping. The underlying molecular mechanisms may involve early (by P9) and enduring reduction of hypothalamic corticotropin-releasing factor (CRF) expression and subsequent (by P45) increase in hippocampal glucocorticoid receptor (GR) expression. However, whether hypothalamic CRF levels influence changes in hippocampal GR expression (and memory function), via reduced CRF receptor activation and consequent lower plasma glucocorticoid levels, is unclear. In this study we administered selective antagonist for the type 1 CRF receptor, NBI 30775, to nonhandled rats post hoc from P10–17 and examined hippocampus-dependent learning and memory later (on P50–70), using two independent paradigms, compared with naive and vehicle-treated nonhandled, and naive and antagonist-treated handled rats. Hippocampal GR and hypothalamic CRF mRNA levels and stress-induced plasma corticosterone levels were also examined. Transient, partial selective blockade of CRF1 in nonhandled rats improved memory functions on both the Morris watermaze and object recognition tests to levels significantly better than in naive and vehicle-treated controls and were indistinguishable from those in handled (naive, vehicle-treated, and antagonist-treated) rats. GR mRNA expression was increased in hippocampal CA1 and the dentate gyrus of CRF1-antagonist treated nonhandled rats to levels commensurate with those in handled cohorts. Thus, the extent of CRF1 activation, probably involving changes in hypothalamic CRF levels and release, contributes to the changes in hippocampal GR expression and learning and memory functions. PMID:15932935

  12. Cytokine modulation by glucocorticoids: mechanisms and actions in cellular studies.

    PubMed

    Brattsand, R; Linden, M

    1996-01-01

    Glucocorticoids inhibit the expression and action of most cytokines. This is part of the in vivo feed-back system between inflammation-derived cytokines and CNS-adrenal produced corticosteroids with the probable physiological relevance to balance parts of the host defence and anti-inflammatory systems of the body. Glucocorticoids modulate cytokine expression by a combination of genomic mechanisms. The activated glucocorticoid-receptor complex can (i) bind to and inactivate key proinflammatory transcription factors (e.g. AP-1, NF kappa B). This takes place at the promotor responsive elements of these factors, but has also been reported without the presence of DNA; (ii) via glucocorticoid responsive elements (GRE), upregulate the expression of cytokine inhibitory proteins, e.g. I kappa B, which inactivates the transcription factor NF kappa B and thereby the secondary expression of a series of cytokines; (iii) reduce the half-life time and utility of cytokine mRNAs. In studies with triggered human blood mononuclear cells in culture, glucocorticoids strongly diminish the production of the 'initial phase' cytokines IL-1 beta and TNF-alpha and the 'immunomodulatory' cytokines IL-2, IL-3, IL-4, IL-5, IL-10, IL-12 and IFN-gamma, as well as of IL-6, IL-8 and the growth factor GM-CSF. While steroid treatment broadly attenuates cytokine production, it cannot modulate it selectively, e.g. just the TH0, the TH1 or the TH2 pathways. The production of the 'anti-inflammatory' IL-10 is also inhibited. The exceptions of steroid down-regulatory activity on cytokine expression seem to affect 'repair phase' cytokines like TGF-beta and PDGF. These are even reported to be upregulated, which may explain the rather weak steroid dampening action on healing and fibrotic processes. Some growth factors, e.g. G-CSF and M-CSF, are only weakly affected. In addition to diminishing the production of a cytokine, steroids can also often inhibit its subsequent actions. Because cytokines work in

  13. Retinoic Acid-inducible Gene I-inducible miR-23b Inhibits Infections by Minor Group Rhinoviruses through Down-regulation of the Very Low Density Lipoprotein Receptor*

    PubMed Central

    Ouda, Ryota; Onomoto, Koji; Takahasi, Kiyohiro; Edwards, Michael R.; Kato, Hiroki; Yoneyama, Mitsutoshi; Fujita, Takashi

    2011-01-01

    In mammals, viral infections are detected by innate immune receptors, including Toll-like receptor and retinoic acid inducible gene I (RIG-I)-like receptor (RLR), which activate the type I interferon (IFN) system. IFN essentially activates genes encoding antiviral proteins that inhibit various steps of viral replication as well as facilitate the subsequent activation of acquired immune responses. In this study, we investigated the expression of non-coding RNA upon viral infection or RLR activation. Using a microarray, we identified several microRNAs (miRNA) specifically induced to express by RLR signaling. As suggested by Bioinformatics (miRBase Target Data base), one of the RLR-inducible miRNAs, miR-23b, actually knocked down the expression of very low density lipoprotein receptor (VLDLR) and LDLR-related protein 5 (LRP5). Transfection of miR-23b specifically inhibited infection of rhinovirus 1B (RV1B), which utilizes the low density lipoprotein receptor (LDLR) family for viral entry. Conversely, introduction of anti-miRNA-23b enhanced the viral yield. Knockdown experiments using small interfering RNA (siRNA) revealed that VLDLR, but not LRP5, is critical for an efficient infection by RV1B. Furthermore, experiments with the transfection of infectious viral RNA revealed that miR-23b did not affect post-entry viral replication. Our results strongly suggest that RIG-I signaling results in the inhibitions of infections of RV1B through the miR-23b-mediated down-regulation of its receptor VLDLR. PMID:21642441

  14. Retinoic acid-inducible gene I-inducible miR-23b inhibits infections by minor group rhinoviruses through down-regulation of the very low density lipoprotein receptor.

    PubMed

    Ouda, Ryota; Onomoto, Koji; Takahasi, Kiyohiro; Edwards, Michael R; Kato, Hiroki; Yoneyama, Mitsutoshi; Fujita, Takashi

    2011-07-22

    In mammals, viral infections are detected by innate immune receptors, including Toll-like receptor and retinoic acid inducible gene I (RIG-I)-like receptor (RLR), which activate the type I interferon (IFN) system. IFN essentially activates genes encoding antiviral proteins that inhibit various steps of viral replication as well as facilitate the subsequent activation of acquired immune responses. In this study, we investigated the expression of non-coding RNA upon viral infection or RLR activation. Using a microarray, we identified several microRNAs (miRNA) specifically induced to express by RLR signaling. As suggested by Bioinformatics (miRBase Target Data base), one of the RLR-inducible miRNAs, miR-23b, actually knocked down the expression of very low density lipoprotein receptor (VLDLR) and LDLR-related protein 5 (LRP5). Transfection of miR-23b specifically inhibited infection of rhinovirus 1B (RV1B), which utilizes the low density lipoprotein receptor (LDLR) family for viral entry. Conversely, introduction of anti-miRNA-23b enhanced the viral yield. Knockdown experiments using small interfering RNA (siRNA) revealed that VLDLR, but not LRP5, is critical for an efficient infection by RV1B. Furthermore, experiments with the transfection of infectious viral RNA revealed that miR-23b did not affect post-entry viral replication. Our results strongly suggest that RIG-I signaling results in the inhibitions of infections of RV1B through the miR-23b-mediated down-regulation of its receptor VLDLR.

  15. Antagonist-mediated down-regulation of toll-like receptors increases the prevalence of human papillomavirus infection in systemic lupus erythematosus

    PubMed Central

    2012-01-01

    Introduction Prevalence of an abnormal Papanicolaou smear was significantly increased in lupus patients in cross-sectional studies, associated with a higher prevalence of high-risk human papillomavirus (HPV) infection. The nucleic acid-specific Toll-like receptors (TLRs) locate at the endolysosomal compartments and trigger the induction of cytokines for the innate immune response. This study evaluated whether abnormal host innate immune response in lupus patients may enhance HPV persistence. Methods Protein levels of TLRs 3, 7, 8 and 9 in cervical epithelial cells of lupus patients and controls with or without HPV infection were assessed using flow cytometry. Characteristics associated with the differential expression of TLRs in systemic lupus erythematosus (SLE) were elucidated. The effect and interferon-stimulated genes (ISGs) (ISG15 and Mx-1) gene expressions were then measured in oncogenic HeLa (HPV18), CaSki (HPV) and C33A (HPV negative) cell lines using flow cytometry and quantitative real-time PCR. Ex vivo productions of cytokines and interferon-gamma (IFN-γ) upon TLR ligands stimulations were subsequently measured using cytometric bead array and ELISA. Results For subjects with HPV infection, levels of TLR3 and TLR7 were significantly lower in lupus patients compared with controls. Significantly decreased TLRs 7, 8 and 9 levels were observed in HPV-negative SLE compared to healthy controls. For SLE with and without HPV infection, TLR7 and 9 levels were significantly lower in infected SLE than those in HPV-negative patients. Independent explanatory variables associated with down-regulation of TLR7 level included HPV infection and a higher cumulative dose of prednisolone; while a higher cumulative dose of hydroxychloroquine and HPV infection were associated with down-regulation of TLR9 level. In cervical cell lines, TLRs 3, 7, 8, 9 protein levels and antiviral ISG15 and Mx-1 gene expressions were inhibited in two oncogenic HPV types. Functional data showed

  16. Boehringer Ingleheim's selective glucocorticoid receptor agonist development candidate: evaluation of WO2010141331, WO2010141332 and WO2010141333.

    PubMed

    Norman, Peter

    2011-07-01

    Three applications from Boehringer Ingelheim all relate to the preparation of non-steroidal glucocorticoid receptor agonists useful in the treatment of inflammatory respiratory diseases. The first two applications claim chiral processes for the preparation of these compounds or intermediates useful therein. These provide two alternative routes, respectively, using achiral and chiral reagents. The third application relates to the preparation of a crystalline salt of the preferred compound on a multi-kilogram scale in micronised form.

  17. The transformed glucocorticoid receptor has a lower steroid-binding affinity than the nontransformed receptor

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Nemoto, Takayuki; Ohara-Nemoto, Yuko; Denis, M.

    1990-02-20

    High-salt treatment of cytosolic glucocorticoid receptor (GR) preparations reduces the steroid-binding ability of the receptor and induces the conversion of the receptor from a nontransformed (non-DNA-binding) 9S form to a transformed (DNA-binding) 4S entity. Therefore, the authors decided to investigate the possible relationship between these two phenomena. The binding of ({sup 3}H)triamcinolone acetonide (({sup 3}H)TA) to the 9S form was almost saturated at a concentration of 20 nM, whereas ({sup 3}H)TA was hardly bound to the 4S form at this concentration. The 4S form was efficiently labeled at 200 nM. Scatchard analysis of the GR showed the presence of twomore » types of binding sites. In the absence of molybdate, the ratio of the lower affinity site was increased, but the total number of binding sites was not modified. The GR with the low ({sup 3}H)TA-binding affinity bound to DNA-cellulose even in its unliganded state, whereas the form with the high affinity did not. These results indicate that the transformed GR has a reduced ({sup 3}H)TA-binding affinity as compared to the nontransformed GR. The steroid-binding domain (amino acids 477-777) and the DNA- and steroid-binding domains (amino acids 415-777) of the human GR were expressed in Escherichia coli as protein A fused proteins. Taken together, these results suggest that the component(s) associating with the nontransformed GR, possibly the heat shock protein hsp 90, play(s) an important role in stabilizing the GR in a high-affinity state for steroids.« less

  18. Up-Regulation of PAI-1 and Down-Regulation of uPA Are Involved in Suppression of Invasiveness and Motility of Hepatocellular Carcinoma Cells by a Natural Compound Berberine.

    PubMed

    Wang, Xuanbin; Wang, Ning; Li, Hongliang; Liu, Ming; Cao, Fengjun; Yu, Xianjun; Zhang, Jingxuan; Tan, Yan; Xiang, Longchao; Feng, Yibin

    2016-04-16

    Hepatocellular carcinoma (HCC) is the second leading cause of cancer-related death and its prognosis remains poor due to the high risk of tumor recurrence and metastasis. Berberine (BBR) is a natural compound derived from some medicinal plants, and accumulating evidence has shown its potent anti-tumor activity with diverse action on tumor cells, including inducing cancer cell death and blocking cell cycle and migration. Molecular targets of berberine involved in its inhibitory effect on the invasiveness remains not yet clear. In this study, we identified that berberine exhibits a potent inhibition on the invasion and migration of HCC cells. This was accompanied by a dose-dependent down-regulation of expression of Cyclooxygenase-2 (COX-2), nuclear factor kappa B (NF-κB), urokinase-type plasminogen activator (uPA) and matrix metalloproteinase (MMP)-9 in berberine-treated HCC cells. Furthermore, berberine inactivated p38 and Erk1/2 signaling pathway in HCC cells. Primarily, this may be attributed to the up-regulation of plasminogen activator inhibitor-1 (PAI-1), a tumor suppressor that can antagonize uPA receptor and down-regulation of uPA. Blockade of uPA receptor-associated pathways leads to reduced invasiveness and motility of berberine-treated HCC cells. In conclusion, our findings identified for the first time that inactivation of uPA receptor by up-regulation of PAI-1 and down-regulation of uPA is involved in the inhibitory effect of berberine on HCC cell invasion and migration.

  19. Mutations of glucocorticoid receptor differentially affect AF2 domain activity in a steroid-selective manner to alter the potency and efficacy of gene induction and repression†

    PubMed Central

    Tao, Yong-guang; Xu, Yong; Xu, H. Eric; Simons, S. Stoney

    2009-01-01

    The transcriptional activity of steroid hormones is intimately associated with their structure. Deacylcortivazol (DAC) contains several features that were predicted to make it an inactive glucocorticoid. Nevertheless, gene induction and repression by complexes of glucocorticoid receptor (GR) with DAC occurs with greater potency (lower EC50) than, and equal efficacy (maximal activity, or Amax) to, the very active and smaller synthetic glucocorticoid dexamethasone (Dex). Guided by a recent x-ray structure of DAC bound to the GR ligand binding domain (LBD), we now report that several point mutants in the LBD have little effect on the binding of either agonist steroid. However, these same mutations dramatically alter the Amax and/or EC50 of exogenous and endogenous genes in a manner that depends on steroid structure. In some cases, Dex is no longer a full agonist. These properties appear to result from a preferential inactivation of the AF2 activation domain in the GR LBD of Dex-, but not DAC-, bound receptors. The Dex-bound receptors display normal binding to, but greatly reduced response to, the coactivator TIF2, thus indicating a defect in the transmission efficiency of GR-steroid complex information to the coactivator TIF2. In addition, all GR mutants that are active in gene induction with either Dex or DAC have greatly reduced activity in gene repression. This contrasts with the reports of GR mutations preferentially suppressing GR-mediated induction. The properties of these GR mutants in gene induction support the hypothesis that the Amax and EC50 of GR-controlled gene expression can be independently modified, indicate that the receptor can be modified to favor activity with a specific agonist steroid, and suggest that new ligands with suitable substituents may be able to affect the same LBD conformational changes and thereby broaden the therapeutic applications of glucocorticoid steroids PMID:18578507

  20. Thalidomide inhibits lipopolysaccharide-induced tumor necrosis factor-alpha production via down-regulation of MyD88 expression.

    PubMed

    Noman, Abu Shadat M; Koide, Naoki; Hassan, Ferdaus; I-E-Khuda, Imtiaz; Dagvadorj, Jargalsaikhan; Tumurkhuu, Gantsetseg; Islam, Shamima; Naiki, Yoshikazu; Yoshida, Tomoaki; Yokochi, Takashi

    2009-02-01

    The effect of thalidomide on lipopolysaccharide (LPS)-induced tumor necrosis factor (TNF)-alpha production was studied by using RAW 264.7 murine macrophage-like cells. Thalidomide significantly inhibited LPS-induced TNF-alpha production. Thalidomide prevented the activation of nuclear factor (NF)-KB by down-regulating phosphorylation of inhibitory KB factor (IKB), and IKB kinase (IKK)-alpha and IKK-beta Moreover, thalidomide inhibited LPS-induced phosphorylation of AKT, p38 and stress-activated protein kinase (SAPK)/JNK. The expression of myeloid differentiation factor 88 (MyD88) protein and mRNA was markedly reduced in thalidomide-treated RAW 264.7 cells but there was no significant alteration in the expression of interleukin-1 receptor-associated kinase (IRAK) 1 and TNF receptor-associated factor (TRAF) 6 in the cells. Thalidomide did not affect the cell surface expression of Toll-like receptor (TLR) 4 and CD14, suggesting the impairment of intracellular LPS signalling in thalidomide-treated RAW 264.7 cells. Thalidomide significantly inhibited the TNF-alpha production in response to palmitoyl-Cys(RS)-2,3-di(palmitoyloxy) propyl)-Ala-Gly-OH (Pam(3)Cys) as a MyD88-dependent TLR2 ligand. Therefore, it is suggested that thalidomide might impair LPS signalling via down-regulation of MyD88 protein and mRNA and inhibit LPS-induced TNF-alpha production. The putative mechanism of thalidomide-induced MyD88 down-regulation is discussed.

  1. Cysteine oxidation impairs systemic glucocorticoid responsiveness in children with difficult-to-treat asthma.

    PubMed

    Stephenson, Susan T; Brown, Lou Ann S; Helms, My N; Qu, Hongyan; Brown, Sheena D; Brown, Milton R; Fitzpatrick, Anne M

    2015-08-01

    The mechanisms underlying glucocorticoid responsiveness are largely unknown. Although redox regulation of the glucocorticoid receptor (GR) has been reported, it has not been studied in asthmatic patients. We characterized systemic cysteine oxidation and its association with inflammatory and clinical features in healthy children and children with difficult-to-treat asthma. We hypothesized that cysteine oxidation would be associated with increased markers of oxidative stress and inflammation, increased features of asthma severity, decreased clinically defined glucocorticoid responsiveness, and impaired GR function. PBMCs were collected from healthy children (n = 16) and children with asthma (n = 118) aged 6 to 17 years. Children with difficult-to-treat asthma underwent glucocorticoid responsiveness testing with intramuscular triamcinolone. Cysteine, cystine, and inflammatory chemokines and reactive oxygen species generation were quantified, and expression and activity of the GR were assessed. Cysteine oxidation was present in children with difficult-to-treat asthma and accompanied by increased reactive oxygen species generation and increased CCL3 and CXCL1 mRNA expression. Children with the greatest extent of cysteine oxidation had more features of asthma severity, including poorer symptom control, greater medication use, and less glucocorticoid responsiveness despite inhaled glucocorticoid therapy. Cysteine oxidation also modified the GR protein by decreasing available sulfhydryl groups and decreasing nuclear GR expression and activity. A highly oxidized cysteine redox state promotes a posttranslational modification of the GR that might inhibit its function. Given that cysteine oxidation is prevalent in children with difficult-to-treat asthma, the cysteine redox state might represent a potential therapeutic target for restoration of glucocorticoid responsiveness in this population. Copyright © 2015 American Academy of Allergy, Asthma & Immunology. Published by

  2. Serum and glucocorticoid-regulated kinase 1 regulates neutrophil clearance during inflammation resolution.

    PubMed

    Burgon, Joseph; Robertson, Anne L; Sadiku, Pranvera; Wang, Xingang; Hooper-Greenhill, Edward; Prince, Lynne R; Walker, Paul; Hoggett, Emily E; Ward, Jonathan R; Farrow, Stuart N; Zuercher, William J; Jeffrey, Philip; Savage, Caroline O; Ingham, Philip W; Hurlstone, Adam F; Whyte, Moira K B; Renshaw, Stephen A

    2014-02-15

    The inflammatory response is integral to maintaining health by functioning to resist microbial infection and repair tissue damage. Large numbers of neutrophils are recruited to inflammatory sites to neutralize invading bacteria through phagocytosis and the release of proteases and reactive oxygen species into the extracellular environment. Removal of the original inflammatory stimulus must be accompanied by resolution of the inflammatory response, including neutrophil clearance, to prevent inadvertent tissue damage. Neutrophil apoptosis and its temporary inhibition by survival signals provides a target for anti-inflammatory therapeutics, making it essential to better understand this process. GM-CSF, a neutrophil survival factor, causes a significant increase in mRNA levels for the known anti-apoptotic protein serum and glucocorticoid-regulated kinase 1 (SGK1). We have characterized the expression patterns and regulation of SGK family members in human neutrophils and shown that inhibition of SGK activity completely abrogates the antiapoptotic effect of GM-CSF. Using a transgenic zebrafish model, we have disrupted sgk1 gene function and shown this specifically delays inflammation resolution, without altering neutrophil recruitment to inflammatory sites in vivo. These data suggest SGK1 plays a key role in regulating neutrophil survival signaling and thus may prove a valuable therapeutic target for the treatment of inflammatory disease.

  3. [Role of the Periaqueductal Gray Matter of the Midbrain in Regulation of Somatic Pain Sensitivity During Stress: Participation of Corticotropin-Releasing Factor and Glucocorticoid Hormones].

    PubMed

    Yarushkina, N I; Filaretova, L P

    2015-01-01

    Periaqueductal gray matter of the midbrain (PAGM) plays a crucial role in the regulation of pain sensitivity under stress, involving in the stress-induced analgesia. A key hormonal system of adaptation under stress is the hypothalamic-pituitary-adrenocortical (HPA) axis. HPA axis's hormones, corticotropin-releasing factor (CRF) and glucocorticoids, are involved in stress-induced analgesia. Exogenous hormones of the HPA axis, similarly to the hormones produced under stress, may cause an analgesic effect. CRF-induced analgesia may be provided by glucocorticoid hormones. CRF and glucocorticoids-induced effects on somatic pain sensitivity may be mediated by PAGM. The aim of the review was to analyze the data of literature on the role of PAGM in the regulation of somatic pain sensitivity under stress and in providing of CRF and glucocorticoid-induced analgesia.

  4. General effect of endotoxin on glucocorticoid receptors in mammalian tissues

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Stith, R.D.; McCallum, R.E.

    Considering the ubiquitous nature of glucocorticoid actions and the fact that endotoxin inhibits glucocorticoid action in the liver, we proposed to examine whether endotoxin affected extrahepatic actions of glucocorticoids. Fasted C57BL/6J mice were injected intraperitoneally with endotoxin (LD50) at 0800 and were killed 6 h later. Control mice were injected with an equal volume of saline. /sup 3/H-dexamethasone binding, measured by a new cytosol exchange assay utilizing molybdate plus dithiothreitol, in liver, kidney, skeletal muscle, spleen, lung, and heart tissue was significantly lower in treated than in control mice. The equilibrium dissociation constants were not significantly different, but the numbermore » of available binding sites in each tissue was reduced by endotoxin treatment. Phosphoenolpyruvate carboxykinase activity was significantly reduced in liver but not in kidney. Endotoxin treatment lowered glycogen content in liver but not in skeletal muscle. The reduction observed in the a form of liver glycogen synthase due to endotoxin was not seen in skeletal muscle glycogen synthase a. These data support the proposal that endotoxin or a mediator of its action inhibits systemic glucocorticoid action. The results also emphasize the central role of the liver in the metabolic disturbances of the endotoxin-treated mouse.« less

  5. Decreased expression of serum- and glucocorticoid-inducible kinase 1 (SGK1) promotes alpha-synuclein increase related with down-regulation of dopaminergic cell in the Substantia Nigra of chronic MPTP-induced Parkinsonism mice and in SH-SY5Y cells.

    PubMed

    Yeo, Sujung; Sung, Backil; Hong, Yeon-Mi; van den Noort, Maurits; Bosch, Peggy; Lee, Sook-Hyun; Song, Jongbeom; Park, Sang-Kyun; Lim, Sabina

    2018-06-30

    Parkinson's disease (PD) is a chronically progressive neurodegenerative disease, with its main pathological hallmarks being a dramatic loss of dopaminergic neurons predominantly in the Substantia Nigra (SN), and the formations of intracytoplasmic Lewy bodies and dystrophic neurites. Alpha-synuclein (α-syn), widely recognized as the most prominent element of the Lewy body, is one of the representative hallmarks in PD. However, the mechanisms behind the increased α-syn expression and aggregation have not yet been clarified. To examine what causes α-syn expression to increase, we analyzed the pattern of gene expression in the SN of mice intoxicated with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), where down-regulation of dopaminergic cells occurred. We identified serum- and glucocorticoid-dependent kinase 1 (SGK1) as one of the genes that is evidently downregulated in chronic MPTP-intoxication. The results of Western blot analyses showed that, together with the down-regulation of dopaminergic cells, the decrease in SGK1 expression increased α-syn expression in the SN in a chronic MPTP-induced Parkinsonism mouse. For an examination of the expression correlation between SGK1 and α-syn, SH-5YSY cells were knocked down with SGK1 siRNA then, the downregulation of dopaminergic cells and the increase in the expression of α-syn were observed. These results suggest that decreased expression of SGK1 may play a critical role in increasing the expression of α-syn, which is related with dopaminergic cell death in the SN of chronic MPTP-induced Parkinsonism mice and in SH-SY5Y cells. Copyright © 2018. Published by Elsevier B.V.

  6. Dexamethasone regulates glutamine synthetase expression in rat skeletal muscles

    NASA Technical Reports Server (NTRS)

    Max, Stephen R.; Konagaya, Masaaki; Konagaya, Yoko; Thomas, John W.; Banner, Carl; Vitkovic, Ljubisa

    1986-01-01

    The regulation of glutamine synthetase by glucocorticoids in rat skeletal muscles was studied. Administration of dexamethasone strikingly enhanced glutamine synthetase activity in plantaris and soleus muscles. The dexamethasone-mediated induction of glutamine synthetase activity was blocked to a significant extent by orally administered RU38486, a glucocorticoid antagonist, indicating the involvement of intracellular glucocorticoid receptors in the induction. Northern blot analysis revealed that dexamethasone-mediated enhancement of glutamine synthetase activity involves dramatically increased levels of glutamine synthetase mRNA. The induction of glutamine synthetase was selective in that glutaminase activity of soleus and plantaris muscles was not increased by dexamethasone. Furthermore, dexamethasone treatment resulted in only a small increase in glutamine synthetase activity in the heart. Accordingly, there was only a slight change in glutamine synthetase mRNA level in this tissue. Thus, glucocorticoids regulate glutamine synthetase gene expression in rat muscles at the transcriptional level via interaction with intracellular glutamine production by muscle and to mechanisms underlying glucocorticoid-induced muscle atrophy.

  7. Glucocorticoids promote Von Hippel Lindau degradation and Hif-1α stabilization

    PubMed Central

    Greenald, David; Wilson, Garrick K.; Peron, Margherita; Markham, Eleanor; Sinnakaruppan, Mathavan; Matthews, Laura C.; McKeating, Jane A.; Argenton, Francesco; van Eeden, Fredericus J. M.

    2017-01-01

    Glucocorticoid (GC) and hypoxic transcriptional responses play a central role in tissue homeostasis and regulate the cellular response to stress and inflammation, highlighting the potential for cross-talk between these two signaling pathways. We present results from an unbiased in vivo chemical screen in zebrafish that identifies GCs as activators of hypoxia-inducible factors (HIFs) in the liver. GCs activated consensus hypoxia response element (HRE) reporters in a glucocorticoid receptor (GR)-dependent manner. Importantly, GCs activated HIF transcriptional responses in a zebrafish mutant line harboring a point mutation in the GR DNA-binding domain, suggesting a nontranscriptional route for GR to activate HIF signaling. We noted that GCs increase the transcription of several key regulators of glucose metabolism that contain HREs, suggesting a role for GC/HIF cross-talk in regulating glucose homeostasis. Importantly, we show that GCs stabilize HIF protein in intact human liver tissue and isolated hepatocytes. We find that GCs limit the expression of Von Hippel Lindau protein (pVHL), a negative regulator of HIF, and that treatment with the c-src inhibitor PP2 rescued this effect, suggesting a role for GCs in promoting c-src–mediated proteosomal degradation of pVHL. Our data support a model for GCs to stabilize HIF through activation of c-src and subsequent destabilization of pVHL. PMID:28851829

  8. Glucocorticoid receptor gene inactivation in dopamine-innervated areas selectively decreases behavioral responses to amphetamine

    PubMed Central

    Parnaudeau, Sébastien; Dongelmans, Marie-louise; Turiault, Marc; Ambroggi, Frédéric; Delbes, Anne-Sophie; Cansell, Céline; Luquet, Serge; Piazza, Pier-Vincenzo; Tronche, François; Barik, Jacques

    2014-01-01

    The meso-cortico-limbic system, via dopamine release, encodes the rewarding and reinforcing properties of natural rewards. It is also activated in response to abused substances and is believed to support drug-related behaviors. Dysfunctions of this system lead to several psychiatric conditions including feeding disorders and drug addiction. These disorders are also largely influenced by environmental factors and in particular stress exposure. Stressors activate the corticotrope axis ultimately leading to glucocorticoid hormone (GCs) release. GCs bind the glucocorticoid receptor (GR) a transcription factor ubiquitously expressed including within the meso-cortico-limbic tract. While GR within dopamine-innervated areas drives cocaine's behavioral responses, its implication in responses to other psychostimulants such as amphetamine has never been clearly established. Moreover, while extensive work has been made to uncover the role of this receptor in addicted behaviors, its contribution to the rewarding and reinforcing properties of food has yet to be investigated. Using mouse models carrying GR gene inactivation in either dopamine neurons or in dopamine-innervated areas, we found that GR in dopamine responsive neurons is essential to properly build amphetamine-induced conditioned place preference and locomotor sensitization. c-Fos quantification in the nucleus accumbens further confirmed defective neuronal activation following amphetamine injection. These diminished neuronal and behavioral responses to amphetamine may involve alterations in glutamate transmission as suggested by the decreased MK801-elicited hyperlocomotion and by the hyporeactivity to glutamate of a subpopulation of medium spiny neurons. In contrast, GR inactivation did not affect rewarding and reinforcing properties of food suggesting that responding for natural reward under basal conditions is preserved in these mice. PMID:24574986

  9. Postnatal epigenetic modification of glucocorticoid receptor gene in preterm infants: a prospective cohort study

    PubMed Central

    Kantake, Masato; Yoshitake, Hiroshi; Ishikawa, Hitoshi; Araki, Yoshihiko; Shimizu, Toshiaki

    2014-01-01

    Objective To examine the environmental effects on cytosine methylation of preterm infant's DNA, because early life experiences are considered to influence the physiological and mental health of an individual through epigenetic modification of DNA. Design A prospective cohort study, comparison of epigenetic differences in the glucocorticoid receptor (GR) gene between healthy term and preterm infants. Setting Neonatal Intensive Care Unit in a Japanese University Hospital. Participants A cohort of 40 (20 term and 20 preterm) infants was recruited on the day of birth, and peripheral blood was obtained from each infant at birth and on postnatal day 4. Main outcome measures The methylation rates in the 1-F promoter region of the GR gene using the Mquant method. Results The methylation rate increased significantly between postnatal days 0 and 4 in preterm infants but remained stable in term infants. Thus, the methylation rate was significantly higher in preterm than in term infants at postnatal day 4. Several perinatal parameters were significantly correlated with this change in the methylation rate. Logistic regression analysis revealed that methylation rates at postnatal day 4 predicted the occurrence of later complications that required glucocorticoid administration during the neonatal period. No gene polymorphism was detected within the GR promoter region analysed. Conclusions Although further large-scale studies are needed to detect the environmental factors that explain the difference in epigenetic modification among infants after birth, our data show that the postnatal environment influences epigenetic programming of GR expression through methylation of the GR gene promoter in premature infants, which may result in relative glucocorticoid insufficiency during the postnatal period. PMID:25023132

  10. Regulation of Hippocampal α1d Adrenergic Receptor mRNA by Corticosterone in Adrenalectomized Rats

    PubMed Central

    Day, Heidi E.W.; Kryskow, Elisa M.; Watson, Stanley J.; Akil, Huda; Campeau, Serge

    2008-01-01

    The hippocampal formation receives extensive noradrenergic projections and expresses high levels of mineralocorticoid (MR) and glucocorticoid (GR) receptors. Considerable evidence suggests that the noradrenergic system influences hippocampal corticosteroid receptors. However, there is relatively little data describing the influence of glucocorticoids on noradrenergic receptors in the hippocampal formation. α1d adrenergic receptor (ADR) mRNA is expressed at high levels in the hippocampal formation, within cells that express MR or GR. In order to determine whether expression of α1d ADR mRNA is influenced by circulating glucocorticoids, male rats underwent bilateral adrenalectomy (ADX) or sham surgery, and were killed after 1, 3, 7 or 14 days. Levels of α1d ADR mRNA were profoundly decreased in hippocampal subfields CA1, CA2 and CA3 and the medial and lateral blades of the dentate gyrus, as early as 1 day after ADX, as determined by in situ hybridization. The effect was specific for the hippocampal formation, with levels of α1d mRNA unaltered by ADX in the lateral amygdala, reticular thalamic nucleus, retrosplenial cortex or primary somatosensory cortex. Additional rats underwent ADX or sham surgery and received a corticosterone pellet (10 or 50 mg) or placebo for 7 days. Corticosterone replacement prevented the ADX-induced decrease in hippocampal α1d ADR mRNA, with the magnitude of effect depending on corticosterone dose and hippocampal subregion. These data indicate that α1d ADR mRNA expression in the hippocampal formation is highly sensitive to circulating levels of corticosterone, and provides further evidence for a close interaction between glucocorticoids and the noradrenergic system in the hippocampus. PMID:18534559

  11. Glucocorticoid receptors in bronchial epithelial cells in asthma.

    PubMed

    Vachier, I; Chiappara, G; Vignola, A M; Gagliardo, R; Altieri, E; Térouanne, B; Vic, P; Bousquet, J; Godard, P; Chanez, P

    1998-09-01

    The expression of the glucocorticoid receptor (GR) in untreated or in steroid-dependent asthmatic patients is poorly understood. We therefore studied GR mRNA and protein levels in bronchial biopsies obtained from seven untreated asthmatic patients, seven control volunteers, and seven patients with chronic bronchitis. We also studied in bronchial epithelial cells obtained by brushing from 13 untreated asthmatics, 18 steroid-dependent asthmatics, 11 control volunteers, and 12 patients with chronic bronchitis, GR and heat shock protein 90 kD (hsp90) mRNA as well as the immunoreactivity of GR, intercellular adhesion molecule (ICAM-1), and granulocyte macrophage-colony-stimulating factor (GM-CSF). GR mRNA and protein level was similar in all subject groups in both biopsies and bronchial epithelial cells. Hsp90 mRNA level was also similar in all subject groups. ICAM-1 expression was significantly increased in bronchial epithelial cells from untreated asthmatics, but ICAM-1 was not expressed in those from steroid-dependent asthmatic patients. GM-CSF expression was significantly increased in bronchial epithelial cells from untreated and steroid-dependent asthmatic patients. GR expression within the airways is unaltered by oral long-term steroid treatment in asthma, but the expression of some but not all specific markers for asthma is modified by oral steroid.

  12. Cannabinoids and glucocorticoids modulate emotional memory after stress.

    PubMed

    Akirav, Irit

    2013-12-01

    Bidirectional and functional relationships between glucocorticoids and the endocannabinoid system have been demonstrated. Here, I review the interaction between the endocannabinoid and glucocorticoid/stress systems. Specifically, stress is known to produce rapid changes in endocannabinoid signaling in stress-responsive brain regions. In turn, the endocannabinoid system plays an important role in the downregulation and habituation of hypothalamic-pituitary-adrenocortical (HPA) axis activity in response to stress. Glucocorticoids also recruit the endocannabinoid system to exert rapid negative feedback control of the HPA axis during stress. It became increasingly clear, however, that cannabinoid CB1 receptors are also abundantly expressed in the basolateral amygdala (BLA) and other limbic regions where they modulate emotional arousal effects on memory. Enhancing cannabinoids signaling using exogenous CB1 receptor agonists prevent the effects of acute stress on emotional memory. I propose a model suggesting that the ameliorating effects of exogenously administered cannabinoids on emotional learning after acute stress are mediated by the decrease in the activity of the HPA axis via GABAergic mechanisms in the amygdala. Copyright © 2013 Elsevier Ltd. All rights reserved.

  13. CRTC2 Is a Coactivator of GR and Couples GR and CREB in the Regulation of Hepatic Gluconeogenesis.

    PubMed

    Hill, Micah J; Suzuki, Shigeru; Segars, James H; Kino, Tomoshige

    2016-01-01

    Glucocorticoid hormones play essential roles in the regulation of gluconeogenesis in the liver, an adaptive response that is required for the maintenance of circulating glucose levels during fasting. Glucocorticoids do this by cooperating with glucagon, which is secreted from pancreatic islets to activate the cAMP-signaling pathway in hepatocytes. The cAMP-response element-binding protein (CREB)-regulated transcription coactivator 2 (CRTC2) is a coactivator known to be specific to CREB and plays a central role in the glucagon-mediated activation of gluconeogenesis in the early phase of fasting. We show here that CRTC2 also functions as a coactivator for the glucocorticoid receptor (GR). CRTC2 strongly enhances GR-induced transcriptional activity of glucocorticoid-responsive genes. CRTC2 physically interacts with the ligand-binding domain of the GR through a region spanning amino acids 561-693. Further, CRTC2 is required for the glucocorticoid-associated cooperative mRNA expression of the glucose-6-phosphatase, a rate-limiting enzyme for hepatic gluconeogenesis, by facilitating the attraction of GR and itself to its promoter region already occupied by CREB. CRTC2 is required for the maintenance of blood glucose levels during fasting in mice by enhancing the GR transcriptional activity on both the G6p and phosphoenolpyruvate carboxykinase (Pepck) genes. Finally, CRTC2 modulates the transcriptional activity of the progesterone receptor, indicating that it may influence the transcriptional activity of other steroid/nuclear receptors. Taken together, these results reveal that CRTC2 plays an essential role in the regulation of hepatic gluconeogenesis through coordinated regulation of the glucocorticoid/GR- and glucagon/CREB-signaling pathways on the key genes G6P and PEPCK.

  14. Effects of prenatal and postnatal depression, and maternal stroking, at the glucocorticoid receptor gene.

    PubMed

    Murgatroyd, C; Quinn, J P; Sharp, H M; Pickles, A; Hill, J

    2015-05-05

    In animal models, prenatal and postnatal stress is associated with elevated hypothalamic-pituitary axis (HPA) reactivity mediated via altered glucocorticoid receptor (GR) gene expression. Postnatal tactile stimulation is associated with reduced HPA reactivity mediated via increased GR gene expression. In this first study in humans to examine the joint effects of prenatal and postnatal environmental exposures, we report that GR gene (NR3C1) 1-F promoter methylation in infants is elevated in the presence of increased maternal postnatal depression following low prenatal depression, and that this effect is reversed by self-reported stroking of the infants by their mothers over the first weeks of life.

  15. Compound A, a Selective Glucocorticoid Receptor Modulator, Enhances Heat Shock Protein Hsp70 Gene Promoter Activation

    PubMed Central

    Beck, Ilse M.; Drebert, Zuzanna J.; Hoya-Arias, Ruben; Bahar, Ali A.; Devos, Michael; Clarisse, Dorien; Desmet, Sofie; Bougarne, Nadia; Ruttens, Bart; Gossye, Valerie; Denecker, Geertrui; Lievens, Sam; Bracke, Marc; Tavernier, Jan; Declercq, Wim; Gevaert, Kris; Berghe, Wim Vanden; Haegeman, Guy; De Bosscher, Karolien

    2013-01-01

    Compound A possesses glucocorticoid receptor (GR)-dependent anti-inflammatory properties. Just like classical GR ligands, Compound A can repress NF-κB-mediated gene expression. However, the monomeric Compound A-activated GR is unable to trigger glucocorticoid response element-regulated gene expression. The heat shock response potently activates heat shock factor 1 (HSF1), upregulates Hsp70, a known GR chaperone, and also modulates various aspects of inflammation. We found that the selective GR modulator Compound A and heat shock trigger similar cellular effects in A549 lung epithelial cells. With regard to their anti-inflammatory mechanism, heat shock and Compound A are both able to reduce TNF-stimulated IκBα degradation and NF-κB p65 nuclear translocation. We established an interaction between Compound A-activated GR and Hsp70, but remarkably, although the presence of the Hsp70 chaperone as such appears pivotal for the Compound A-mediated inflammatory gene repression, subsequent novel Hsp70 protein synthesis is uncoupled from an observed CpdA-induced Hsp70 mRNA upregulation and hence obsolete in mediating CpdA’s anti-inflammatory effect. The lack of a Compound A-induced increase in Hsp70 protein levels in A549 cells is not mediated by a rapid proteasomal degradation of Hsp70 or by a Compound A-induced general block on translation. Similar to heat shock, Compound A can upregulate transcription of Hsp70 genes in various cell lines and BALB/c mice. Interestingly, whereas Compound A-dependent Hsp70 promoter activation is GR-dependent but HSF1-independent, heat shock-induced Hsp70 expression alternatively occurs in a GR-independent and HSF1-dependent manner in A549 lung epithelial cells. PMID:23935933

  16. Monoclonal antibodies against the rat liver glucocorticoid receptor.

    PubMed Central

    Okret, S; Wikström, A C; Wrange, O; Andersson, B; Gustafsson, J A

    1984-01-01

    Splenic cells from one BALB/c mouse and one C57/BL mouse, immunized with purified rat liver glucocorticoid receptor (GR), were fused with the mouse myeloma cell line Sp 2/0-Ag 14. Screening for production of anti-GR-antibodies by the hybridomas was carried out with an enzyme-linked immunosorbent assay, using partially purified rat liver GR as antigen. Further screening was by a second-antibody immunoprecipitation assay using [3H]triamcinolone acetonide-GR complex from rat liver cytosol as tracer. Hybridomas from 10 different microplate wells, positive in both assays, were successfully cloned by the limiting dilution method to monoclonality. The different origins of the monoclonal antibodies were confirmed by their various isoelectric points when analyzed by isoelectric focusing. Four of the monoclonal hybridoma cell lines secreted IgM antibodies; two, IgG1; three, IgG2a; and one, IgG2b. The GR-antibody complex was identified in glycerol density gradients by a shift of the 4S GR to an 8.5S or 19S GR-antibody complex when incubated with monoclonal IgG or IgM antibody, respectively. The 10 monoclonal antibodies recognized different determinants on the GR, all situated on that domain of the receptor that is separate from the ligand and DNA-binding domains. Also, the cross-reactivity to the mouse liver GR varied among the monoclonal antibodies. No cross-reactivity was observed to the human lymphocytic GR. NaDodSO4 electrophoresis of a 0.5% pure GR preparation followed by immunoblotting using one of the monoclonal antibodies identified a single peptide with a molecular weight of 94,000, identical to the purified rat liver GR. Images PMID:6200880

  17. IFN-beta1b augments glucocorticoid-induced suppression of tumor necrosis factor-alpha production by increasing the number of glucocorticoid receptors on a human monocytic cell line.

    PubMed

    Uitdehaag, B M; Hoekstra, K; Koper, J W; Polman, C H; Dijkstra, C D

    2001-03-01

    We studied the effect of recombinant interferon-beta1b (IFN-beta1b) on the sensitivity to glucocorticoids (GC) and on the number of GC receptors (GCR) in the human monocytic cell line THP-1. We found that IFN-beta1b augments the suppressive effect that dexamethasone has on the stimulated production of tumor necrosis factor-alpha (TNF-alpha), most likely related to the increased number of GCR observed after exposure to IFN-beta1b. This provides a possible clue to the mechanism of action of IFN-beta in multiple sclerosis.

  18. Evidence for glucocorticoid receptor binding to a site(s) in a remote region of the 5' flanking sequences of the human proopiomelanocortin gene

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Tully, D.B.; Hillman, D.; Herbert, E.

    1986-05-01

    Glucocorticoids negatively regulate expression of the human proopiomelanocortin (POMC) gene. It has been postulated that this effect may be modulated by a direct interaction of the glucocorticoid receptor (GR) with DNA in the vicinity of the POMC promoter. In order to investigate interactions of GR with POMC DNA, DNA-cellulose competitive binding assays have been performed using isolated fragments of cloned POMC DNA to compete with calf thymus DNA-cellulose for binding of triamcinolone acetonide affinity-labelled GR prepared from HeLa S/sub 3/ cells. In these assays, two fragments isolated from the 5' flanking sequences of POMC DNA (Fragment 3,-1765 to -677 andmore » Fragment 4, -676 to +125 with respect to the mRNA cap site) have competed favorably, with Fragment 3 consistently competing more strongly than Fragment 4. Additional studies have been conducted utilizing a newly developed South-western Blot procedure in which specific /sup 32/P-labelled DNA fragments are allowed to bind to dexamethasone mesylate labelled GR immobilized on nitrocellulose filters. Results from these studies have also shown preferential binding by POMC DNA fragments 3 and 4. DNA footprinting and gene transfer experiments are now being conducted to further characterize the nature of GR interaction with POMC DNA.« less

  19. The role of glucocorticoids in emotional memory reconsolidation.

    PubMed

    Meir Drexler, Shira; Wolf, Oliver T

    2017-07-01

    Glucocorticoids are secreted following exposure to stressful events. Their modulating role on memory reconsolidation, a post-retrieval process of re-stabilization, has been investigated only recently, at times with conflicting results. The goal of this review is twofold. First, to establish the modulating role of glucocorticoids on memory reconsolidation. Second, to point the potential factors and confounds that might explain the seemingly paradoxical findings. Here we review recent pharmacological studies, conducted in rodents and humans, which suggest a critical role of glucocorticoids in this post-retrieval process. In particular, the activation of glucocorticoid receptors in the amygdala and hippocampus is suggested to be involved in emotional memories reconsolidation, pointing to a similarity between post-retrieval reconsolidation and initial memory consolidation. In addition, based on the general reconsolidation literature, we suggest several factors that might play a role in determining the direction and strength of the reconsolidation effect following glucocorticoids treatment: memory-related factors, manipulation-related factors, and individual differences. We conclude that only when taking these additional factors into account can the paradox be resolved. Copyright © 2016 Elsevier Inc. All rights reserved.

  20. Epigenetic changes in the hypothalamic proopiomelanocortin and glucocorticoid receptor genes in the ovine fetus after periconceptional undernutrition.

    PubMed

    Stevens, Adam; Begum, Ghazala; Cook, Alice; Connor, Kristin; Rumball, Christopher; Oliver, Mark; Challis, John; Bloomfield, Frank; White, Anne

    2010-08-01

    Maternal food restriction is associated with the development of obesity in offspring. This study examined how maternal undernutrition in sheep affects the fetal hypothalamic glucocorticoid receptor (GR) and the appetite-regulating neuropeptides, proopiomelanocortin (POMC) and neuropeptide Y, which it regulates. In fetuses from ewes undernourished from -60 to +30 d around conception, there was increased histone H3K9 acetylation (1.63-fold) and marked hypomethylation (62% decrease) of the POMC gene promoter but no change in POMC expression. In the same group, acetylation of histone H3K9 associated with the hypothalamic GR gene was increased 1.60-fold and the GR promoter region was hypomethylated (53% decrease). In addition, there was a 4.7-fold increase in hypothalamic GR expression but no change in methylation of GR gene expression in the anterior pituitary or hippocampus. Interestingly, hypomethylation of both POMC and GR promoter markers in fetal hypothalami was also identified after maternal undernutrition from -60 to 0 d and -2 to +30 d. In comparison, the Oct4 gene, was hypermethylated in both control and underfed groups. Periconceptional undernutrition is therefore associated with marked epigenetic changes in hypothalamic genes. Increase in GR expression in the undernourished group may contribute to fetal programming of a predisposition to obesity, via altered GR regulation of POMC and neuropeptide Y. These epigenetic changes in GR and POMC in the hypothalamus may also predispose the offspring to altered regulation of food intake, energy expenditure, and glucose homeostasis later in life.

  1. Down-regulation of lipoprotein lipase increases glucose uptake in L6 muscle cells

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Lopez, Veronica; Saraff, Kumuda; Medh, Jheem D., E-mail: jheem.medh@csun.edu

    2009-11-06

    Thiazolidinediones (TZDs) are synthetic hypoglycemic agents used to treat type 2 diabetes. TZDs target the peroxisome proliferator activated receptor-gamma (PPAR-{gamma}) and improve systemic insulin sensitivity. The contributions of specific tissues to TZD action, or the downstream effects of PPAR-{gamma} activation, are not very clear. We have used a rat skeletal muscle cell line (L6 cells) to demonstrate that TZDs directly target PPAR-{gamma} in muscle cells. TZD treatment resulted in a significant repression of lipoprotein lipase (LPL) expression in L6 cells. This repression correlated with an increase in glucose uptake. Down-regulation of LPL message and protein levels using siRNA resulted inmore » a similar increase in insulin-dependent glucose uptake. Thus, LPL down-regulation improved insulin sensitivity independent of TZDs. This finding provides a novel method for the management of insulin resistance.« less

  2. mTOR Is Essential for Corticosteroid Effects on Hippocampal AMPA Receptor Function and Fear Memory

    ERIC Educational Resources Information Center

    Xiong, Hui; Casse, Frédéric; Zhou, Yang; Zhou, Ming; Xiong, Zhi-Qi; Joëls, Marian; Martin, Stéphane; Krugers, Harm J.

    2015-01-01

    Glucocorticoid hormones, via activation of their receptors, promote memory consolidation, but the exact underlying mechanisms remain elusive. We examined how corticosterone regulates AMPA receptors (AMPARs), which are crucial for synaptic plasticity and memory formation. Combining a live imaging fluorescent recovery after photobleaching approach…

  3. Spinal glucocorticoid receptor‑regulated chronic morphine tolerance may be through extracellular signal‑regulated kinase 1/2.

    PubMed

    Zhai, Mei-Li; Chen, Yi; Liu, Chong; Wang, Jian-Bo; Yu, Yong-Hao

    2018-05-23

    Opioid use has been limited in the treatment of chronic pain due to their side effects, including analgesic tolerance. Previous studies demonstrated that glucocorticoid receptors (GRs) may be involved in the development of chronic morphine tolerance; however, the mechanism remains unknown. It was hypothesized that the expression of spinal phosphorylated mitogen‑activated protein kinase [MAPK; phosphorylated extracellular signal‑regulated kinase (ERK)] is regulated through the spinal GRs, following chronic treatment with morphine. In the first experiment, the experimental rats were randomly divided into four groups: Control, morphine, morphine+GR antagonist mifepristone (RU38486) and morphine+GR agonist dexamethasone (Dex). Each group was treated with continuous intrathecal (IT) injection of the drugs for 6 days. The expression of GRs and MAPK 3/1 (p‑ERK 1/2) in the spinal dorsal horn was detected by western blot analysis and immunofluorescence staining. In the second experiment, the MAPK inhibitor PD98059 was added and the rats were randomly divided into four groups: Control, morphine, PD98059+morphine and PD98059+morphine+Dex. The continuous IT injection lasted for 7 days in each group. For all experiments, the tail flick test was conducted 30 min following administration every day to assess the thermal hyperalgesia of the rats. The experimental results demonstrated that there was a co‑existence of GRs and p‑ERK 1/2 in the spinal cord dorsal horn by double immunofluorescence staining. The GR antagonist RU38486 attenuated the morphine analgesia tolerance by inhibiting the expression of GR and increasing the expression of p‑ERK. The MAPK inhibitor PD98059 increased the effect of morphine tolerance and prolonged the duration of morphine tolerance. The present results suggest that spinal GRs may serve an important role in the development of morphine tolerance through the ERK signaling pathway.

  4. HIV turns plasmacytoid dendritic cells (pDC) into TRAIL-expressing killer pDC and down-regulates HIV coreceptors by Toll-like receptor 7-induced IFN-alpha.

    PubMed

    Hardy, Andrew W; Graham, David R; Shearer, Gene M; Herbeuval, Jean-Philippe

    2007-10-30

    Plasmacytoid dendritic cells (pDC) are key players in viral immunity and produce IFN-alpha after HIV-1 exposure, which in turn regulates TNF-related apoptosis-inducing ligand (TRAIL) expression by CD4(+) T cells. We show here that infectious and noninfectious HIV-1 virions induce activation of pDC into TRAIL-expressing IFN-producing killer pDC (IKpDC). IKpDC expressed high levels of activation markers (HLA-DR, CD80, CD83, and CD86) and the migration marker CCR7. Surprisingly, CXCR4 and CCR5 were down-regulated on IKpDC. We also show that HIV-1-induced IKpDC depended on Toll-like receptor 7 (TLR7) activation. HIV-1 or TLR7 agonistexposed IKpDC induced apoptosis of the CD4(+) T cell line SupT1 via the TRAIL pathway. Furthermore, IFN-alpha produced after HIV-induced TLR7 stimulation was responsible for TRAIL expression and the down-regulation of both CXCR4 and CCR5 by IKpDC. In contrast, activation and migration markers were not regulated by IFN-alpha. Finally, IFN-alpha increased the survival of IKpDC. We characterized a subset of pDC with a killer activity that is activated by endosomal-associated viral RNA and not by infection.

  5. Down-modulation of receptors for phorbol ester tumor promoter in primary epidermal cells

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Solanki, V.; Slaga, T.J.

    1982-01-01

    The specific (20-/sup 3/H)phorbol 12,13-dibutyrate ((/sup 3/H)PDBu) binding to intact epidermal cells displayed the phenomenon of down-modulation, i.e., the specific binding of (/sup 3/H)PDBu to its receptors on primary epidermal cells reached a maximum within 1 h and steadily declined thereafter. The apparent down-modulation of radiolabel resulted from a partial loss in the total number of receptors; the affinity of receptors for the ligand was essentially unchanged. A number of agents such as chloroquine, methylamine, or arginine which are known to prevent clustering, down-modulation, and/or internalization of several hormone receptors did not affect the down-modulation of phorbol ester receptors. Furthermore,more » cycloheximide had no effect either on down-modulation or on the binding capacity of cells. The surface binding capacity of down-modulated cells following a 90-min incubation with unlabeled ligand was almost returned to normal within 1 h. The effect of the antidepressant drug chlorpromazine, which is known to interact with calmodulin, on (/sup 3/H)PDBu binding was also investigated. Our data indicate that the effect of chlorpromazine on (/sup 3/H)PDBu binding is probably unrelated to its calmodulin-binding activity.« less

  6. INCREASED OXIDATIVE STRESS AND DOWN REGULATION OF ENDOTHELIAL NITRIC OXIDE SYNTHASE (ENOS) IN THE KIDNEY ATTEN- UATE THE RESPONSIVENESS OF (XlB ADRENERGIC RECEPTORS IN THE KIDNEY OF RATS WITH LEFT VENTRICULAR HYPERTROPHY.

    PubMed

    Ahmad, Ashfaq; Sattar, Munavvar; Khan, Safia Akhtar; Abdullah, Nor A; Johns, Edward J; Afzal, Samina

    2017-03-01

    Present study explored endothelial nitric oxide synthase/nitric oxide (eNOS/NO) pathway in the kidney and role of αIB adrenergic receptor in the regulation of renal vasculature in the rats with left ventricular hypertrophy (LVH). LVH was induced by administering isoprenaline 5 mg/kg (s.c. 72 h. apart) and caffeine (62 mg/L in drinking water) for 14 days. Quantification of molecular expression of eNOS in kidney was performed by quantitative Real Time Polymerase Chain Reaction (qPCR). Renal vasoconstrictor responses were measured by administering noradrenaline (NA), phenylephrine (PE) and methoxamine (ME) in pre-drug phase, low dose and high dose phases of chloroethylelonidine (CEC), a selective of (αIB adrenergic receptor antagonist. In the kidney of LVH male Wistar Kyoto (WKY) rats eNOS was significantly down regulated (p < 0.05) by 74% relative to Control WKY (taken as 100%). The high dose 5 CEC attenuated the vasoconstrictor responses to NA by 41%, PE by 43% and ME by 33% in the LVH-WKY when compared to the same dose phase in Control WKY group. In LVH, increased oxidative stress in kidney and increased ACE activity in the plasma resulted in down regulation of eNOS/NO in the kidney. The renal vasoconstrictor responses to adrenergic agonist are blunted in LVH and (αIB adrenergic receptor is functional subtype in renal vasculature in LVH.

  7. Org 214007-0: a novel non-steroidal selective glucocorticoid receptor modulator with full anti-inflammatory properties and improved therapeutic index.

    PubMed

    van Lierop, Marie-José C; Alkema, Wynand; Laskewitz, Anke J; Dijkema, Rein; van der Maaden, Hans M; Smit, Martin J; Plate, Ralf; Conti, Paolo G M; Jans, Christan G J M; Timmers, C Marco; van Boeckel, Constant A A; Lusher, Scott J; McGuire, Ross; van Schaik, Rene C; de Vlieg, Jacob; Smeets, Ruben L; Hofstra, Claudia L; Boots, Annemieke M H; van Duin, Marcel; Ingelse, Benno A; Schoonen, Willem G E J; Grefhorst, Aldo; van Dijk, Theo H; Kuipers, Folkert; Dokter, Wim H A

    2012-01-01

    Glucocorticoids (GCs) such as prednisolone are potent immunosuppressive drugs but suffer from severe adverse effects, including the induction of insulin resistance. Therefore, development of so-called Selective Glucocorticoid Receptor Modulators (SGRM) is highly desirable. Here we describe a non-steroidal Glucocorticoid Receptor (GR)-selective compound (Org 214007-0) with a binding affinity to GR similar to that of prednisolone. Structural modelling of the GR-Org 214007-0 binding site shows disturbance of the loop between helix 11 and helix 12 of GR, confirmed by partial recruitment of the TIF2-3 peptide. Using various cell lines and primary human cells, we show here that Org 214007-0 acts as a partial GC agonist, since it repressed inflammatory genes and was less effective in induction of metabolic genes. More importantly, in vivo studies in mice indicated that Org 214007-0 retained full efficacy in acute inflammation models as well as in a chronic collagen-induced arthritis (CIA) model. Gene expression profiling of muscle tissue derived from arthritic mice showed a partial activity of Org 214007-0 at an equi-efficacious dosage of prednisolone, with an increased ratio in repression versus induction of genes. Finally, in mice Org 214007-0 did not induce elevated fasting glucose nor the shift in glucose/glycogen balance in the liver seen with an equi-efficacious dose of prednisolone. All together, our data demonstrate that Org 214007-0 is a novel SGRMs with an improved therapeutic index compared to prednisolone. This class of SGRMs can contribute to effective anti-inflammatory therapy with a lower risk for metabolic side effects.

  8. Glucocorticoids Suppress Renal Cell Carcinoma Progression by Enhancing Na,K-ATPase Beta-1 Subunit Expression

    PubMed Central

    Huynh, Thu P.; Barwe, Sonali P.; Lee, Seung J.; McSpadden, Ryan; Franco, Omar E.; Hayward, Simon W.; Damoiseaux, Robert; Grubbs, Stephen S.; Petrelli, Nicholas J.; Rajasekaran, Ayyappan K.

    2015-01-01

    Glucocorticoids are commonly used as palliative or chemotherapeutic clinical agents for treatment of a variety of cancers. Although steroid treatment is beneficial, the mechanisms by which steroids improve outcome in cancer patients are not well understood. Na,K-ATPase beta-subunit isoform 1 (NaK-β1) is a cell-cell adhesion molecule, and its expression is down-regulated in cancer cells undergoing epithelial-to mesenchymal-transition (EMT), a key event associated with cancer progression to metastatic disease. In this study, we performed high-throughput screening to identify small molecules that could up-regulate NaK-β1 expression in cancer cells. Compounds related to the glucocorticoids were identified as drug candidates enhancing NaK-β1 expression. Of these compounds, triamcinolone, dexamethasone, and fluorometholone were validated to increase NaK-β1 expression at the cell surface, enhance cell-cell adhesion, attenuate motility and invasiveness and induce mesenchymal to epithelial like transition of renal cell carcinoma (RCC) cells in vitro. Treatment of NaK-β1 knockdown cells with these drug candidates confirmed that these compounds mediate their effects through up-regulating NaK-β1. Furthermore, we demonstrated that these compounds attenuate tumor growth in subcutaneous RCC xenografts and reduce local invasiveness in orthotopically-implanted tumors. Our results strongly indicate that the addition of glucocorticoids in the treatment of RCC may improve outcome for RCC patients by augmenting NaK-β1 cell-cell adhesion function. PMID:25836370

  9. Regulation of aldosterone secretion by mineralocorticoid receptor-mediated signaling.

    PubMed

    Chong, Cherish; Hamid, Anis; Yao, Tham; Garza, Amanda E; Pojoga, Luminita H; Adler, Gail K; Romero, Jose R; Williams, Gordon H

    2017-03-01

    We posit the existence of a paracrine/autocrine negative feedback loop, mediated by the mineralocorticoid receptor (MR), regulating aldosterone secretion. To assess this hypothesis, we asked whether altering MR activity in zona glomerulosa (ZG) cells affects aldosterone production. To this end, we studied ex vivo ZG cells isolated from male Wistar rats fed chow containing either high (1.6% Na + (HS)) or low (0.03% Na + (LS)) amount of sodium. Western blot analyses demonstrated that MR was present in both the ZG and zona fasciculata/zona reticularis (ZF/ZR/ZR). In ZG cells isolated from rats on LS chow, MR activation by fludrocortisone produced a 20% and 60% reduction in aldosterone secretion basally and in response to angiotensin II (ANGII) stimulation, respectively. Corticosterone secretion was increased in these cells suggesting that aldosterone synthase activity was being reduced by fludrocortisone. In contrast, canrenoic acid, an MR antagonist, enhanced aldosterone production by up to 30% both basally and in response to ANGII. Similar responses were observed in ZG cells from rats fed HS. Modulating glucocorticoid receptor (GR) activity did not alter aldosterone production by ZG cells; however, altering GR activity did modify corticosterone production from ZF/ZR/ZR cells both basally and in response to adrenocorticotropic hormone (ACTH). Additionally, activating the MR in ZF/ZR/ZR cells strikingly reduced corticosterone secretion. In summary, these data support the hypothesis that negative ultra-short feedback loops regulate adrenal steroidogenesis. In the ZG, aldosterone secretion is regulated by the MR, but not the GR, an effect that appears to be secondary to a change in aldosterone synthase activity. © 2017 Society for Endocrinology.

  10. Are BDNF and glucocorticoid activities calibrated?

    PubMed Central

    Jeanneteau, Freddy; Chao, Moses V.

    2012-01-01

    One hypothesis to account for the onset and severity of neurological disorders is the loss of trophic support. Indeed, changes in the levels and activities of brain-derived neurotrophic factor (BDNF) occur in numerous neurodegenerative and neuropsychiatric diseases. A deficit promotes vulnerability whereas a gain of function facilitates recovery by enhancing survival, synapse formation and synaptic plasticity. Implementation of ‘BDNF therapies’, however, faces numerous methodological and pharmacokinetic issues. Identifying BDNF mimetics that activate the BDNF receptor or downstream targets of BDNF signaling represent an alternative approach. One mechanism that shows great promise is to study the interplay of BDNF and glucocorticoid hormones, a major class of natural steroid secreted during stress reactions and in synchrony with circadian rhythms. While small amounts of glucocorticoids support normal brain function, excess stimulation by these steroid hormones precipitate stress-related affective disorders. To date, however, because of the paucity of knowledge of underlying cellular mechanisms, deleterious effects of glucocorticoids are not prevented following extreme stress. In the present review, we will discuss the complementary roles share by BDNF and glucocorticoids in synaptic plasticity, and delineate possible signaling mechanisms mediating these effects. PMID:23022538

  11. Regulation of gonadotropin receptors on cultured porcine Leydig and Sertoli cells: effect of potassium depletion.

    PubMed

    Bernier, M; Laferrere, B; Jaillard, C; Clerget, M; Saez, J M

    1986-06-01

    We have examined the role of the NaK-ATPase pump activity on the ligand-induced down-regulation of gonadotropin receptors in cultured porcine Leydig and Sertoli cells. In both cells, inhibition of the NaK pump by ouabain produced a depletion of intracellular K+ levels (ID50, 10(-7) M) after a lag period of about 8 h. In the absence of ligand, the number of FSH receptors in ouabain-treated Sertoli cells was unaffected or slightly reduced, whereas a 2-fold increase in the number of human CG (hCG)/LH receptors with small changes in the binding affinity was observed in Leydig cells treated by ouabain. The effect of ouabain was dose dependent. Differences were also observed in the down-regulation process of gonadotropin receptors in ouabain-treated cells. The hCG-induced receptor loss in Leydig cells was completely reversed by ouabain whereas the drug had no effect on ligand-induced loss of FSH receptors in Sertoli cells. Similar results were observed when the cells were incubated in K+-free medium. Kinetics studies with labeled hCG have shown that ouabain treatment slows down significantly the rate of [125I]iodo-hCG internalization (t 1/2, 18 h; control cells, t 1/2, 6 h), but had no effect on the degradation of internalized hormone. The internalization of receptor-bound [125I]iodo-hCG was also reduced when Leydig cells were incubated in K+-free medium, but was restored when this medium was supplemented with rubidium. The influence of the NaK pump on the receptor regulation of a ligand common to both types of cells, such as epidermal growth factor, was studied under the same experimental conditions. Neither ouabain nor K+-free medium were able to prevent the epidermal growth factor-induced reduction of receptor levels in Leydig and Sertoli cells. Thus, it appears that modulation of ligand-induced receptor loss by depletion of cellular K+ levels is not dependent on the cell type, but on the ligand-receptor complex. The data also show a striking difference in the

  12. Historical contingency and its biophysical basis in glucocorticoid receptor evolution.

    PubMed

    Harms, Michael J; Thornton, Joseph W

    2014-08-14

    Understanding how chance historical events shape evolutionary processes is a central goal of evolutionary biology. Direct insights into the extent and causes of evolutionary contingency have been limited to experimental systems, because it is difficult to know what happened in the deep past and to characterize other paths that evolution could have followed. Here we combine ancestral protein reconstruction, directed evolution and biophysical analysis to explore alternative 'might-have-been' trajectories during the ancient evolution of a novel protein function. We previously found that the evolution of cortisol specificity in the ancestral glucocorticoid receptor (GR) was contingent on permissive substitutions, which had no apparent effect on receptor function but were necessary for GR to tolerate the large-effect mutations that caused the shift in specificity. Here we show that alternative mutations that could have permitted the historical function-switching substitutions are extremely rare in the ensemble of genotypes accessible to the ancestral GR. In a library of thousands of variants of the ancestral protein, we recovered historical permissive substitutions but no alternative permissive genotypes. Using biophysical analysis, we found that permissive mutations must satisfy at least three physical requirements--they must stabilize specific local elements of the protein structure, maintain the correct energetic balance between functional conformations, and be compatible with the ancestral and derived structures--thus revealing why permissive mutations are rare. These findings demonstrate that GR evolution depended strongly on improbable, non-deterministic events, and this contingency arose from intrinsic biophysical properties of the protein.

  13. Baicalin promotes hippocampal neurogenesis via SGK1- and FKBP5-mediated glucocorticoid receptor phosphorylation in a neuroendocrine mouse model of anxiety/depression

    PubMed Central

    Zhang, Kuo; Pan, Xing; Wang, Fang; Ma, Jie; Su, Guangyue; Dong, Yingxu; Yang, Jingyu; Wu, Chunfu

    2016-01-01

    Antidepressants increase hippocampal neurogenesis by activating the glucocorticoid receptor (GR), but excessive GR activation impairs hippocampal neurogenesis, suggesting that normal GR function is crucial for hippocampal neurogenesis. Baicalin was reported to regulate the expression of GR and facilitate hippocampal neurogenesis, but the underlying molecular mechanisms are still unknown. In this study, we used the chronic corticosterone (CORT)-induced mouse model of anxiety/depression to assess antidepressant-like effects of baicalin and illuminate possible molecular mechanisms by which baicalin affects GR-mediated hippocampal neurogenesis. We found that oral administration of baicalin (40, 80 or 160 mg/kg) for 4 weeks alleviated several chronic CORT-induced anxiety/depression-like behaviors. Baicalin also increased Ki-67- and DCX-positive cells to restore chronic CORT-induced suppression of hippocampal neurogenesis. Moreover, baicalin normalized the chronic CORT-induced decrease in GR protein levels, the increase in GR nuclear translocation and the increase in GR phosphorylation at Ser203 and Ser211. Finally, chronic CORT exposure increased the level of FK506-binding protein 51 (FKBP5) and of phosphorylated serum- and glucocorticoid-inducible kinase 1 (SGK1) at Ser422 and Thr256, whereas baicalin normalized these changes. Together, our findings suggest that baicalin improves anxiety/depression-like behaviors and promotes hippocampal neurogenesis. We propose that baicalin may normalize GR function through SGK1- and FKBP5-mediated GR phosphorylation. PMID:27502757

  14. Region-specific Alterations in Glucocorticoid Receptor Expression in the Postmortem Brain of Teenage Suicide Victims

    PubMed Central

    Pandey, Ghanshyam N.; Rizavi, Hooriyah S.; Ren, Xinguo; Dwivedi, Yogesh; Palkovits, Miklós

    2013-01-01

    Introduction Abnormal function of the hypothalamic-pituitary-adrenal (HPA) axis has been implicated in the pathophysiology of depression and suicide. The purpose of this study was to test the hypothesis that the reported dysregulation of the HPA axis in suicide may be related to a disturbed feedback inhibition caused by decreased corticoid receptors in the brain. We therefore determined the protein and gene expression of glucocorticoid (GR) and mineralocorticoid receptors (MR) in the postmortem brain of teenage suicide victims and matched normal controls. Methods Protein and mRNA expression of GR (GR-α and GR-β) and MR and the mRNA expression of glucocorticoid-induced leucine zipper (GILZ), a target gene for GR were determined by immunolabeling using Western blot technique and the real-time RT-polymerase chain reaction (qPCR) technique in the prefrontal cortex (PFC), hippocampus, subiculum, and amygdala obtained from 24 teenage suicide victims and 24 teenage control subjects. Results We observed that protein and gene expression of GR-α was significantly decreased in the PFC and amygdala, but not in the hippocampus or subiculum, of teenage suicide victims compared with normal control subjects. Also, the mRNA levels of GR inducible target gene GILZ was significantly decreased in PFC and amygdaloid nuclei but not in hippocampus compared with controls. In contrast, no significant differences were observed in protein or gene expression of MR in any of the areas studied between teenage suicide victims and normal control subjects. There was no difference in the expression of GR-β in the PFC between suicide victims and normal controls. Conclusions These results suggested that the observed dysregulation of the HPA axis in suicide may be related to a decreased expression of GR-α and GR inducible genes in the PFC and amygdala of teenage suicide victims. The reason why GR receptors are not dysregulated in the hippocampus or subiculum, presumably two sites of stress action

  15. The Hsp90-binding peptidylprolyl isomerase FKBP52 potentiates glucocorticoid signaling in vivo

    PubMed Central

    Riggs, Daniel L.; Roberts, Patricia J.; Chirillo, Samantha C.; Cheung-Flynn, Joyce; Prapapanich, Viravan; Ratajczak, Thomas; Gaber, Richard; Picard, Didier; Smith, David F.

    2003-01-01

    Hsp90 is required for the normal activity of steroid receptors, and in steroid receptor complexes it is typically bound to one of the immunophilin-related co-chaperones: the peptidylprolyl isomerases FKBP51, FKBP52 or CyP40, or the protein phosphatase PP5. The physiological roles of the immunophilins in regulating steroid receptor function have not been well defined, and so we examined in vivo the influences of immunophilins on hormone-dependent gene activation in the Saccharomyces cerevisiae model for glucocorticoid receptor (GR) function. FKBP52 selectively potentiates hormone-dependent reporter gene activation by as much as 20-fold at limiting hormone concentrations, and this potentiation is readily blocked by co-expression of the closely related FKBP51. The mechanism for potentiation is an increase in GR hormone-binding affinity that requires both the Hsp90-binding ability and the prolyl isomerase activity of FKBP52. PMID:12606580

  16. Small interfering RNA-mediated down-regulation of caveolin-1 differentially modulates signaling pathways in endothelial cells.

    PubMed

    Gonzalez, Eva; Nagiel, Aaron; Lin, Alison J; Golan, David E; Michel, Thomas

    2004-09-24

    Caveolin-1 is a scaffolding/regulatory protein that interacts with diverse signaling molecules in endothelial cells. To explore the role of this protein in receptor-modulated signaling pathways, we transfected bovine aortic endothelial cells (BAEC) with small interfering RNA (siRNA) duplexes to down-regulate caveolin-1 expression. Transfection of BAEC with duplex siRNA targeted against caveolin-1 mRNA selectively "knocked-down" the expression of caveolin-1 by approximately 90%, as demonstrated by immunoblot analyses of BAEC lysates. We used discontinuous sucrose gradients to purify caveolin-containing lipid rafts from siRNA-treated endothelial cells. Despite the near-total down-regulation of caveolin-1 expression, the lipid raft targeting of diverse signaling proteins (including the endothelial isoform of nitric-oxide synthase, Src-family tyrosine kinases, Galphaq and the insulin receptor) was unchanged. We explored the consequences of caveolin-1 knockdown on kinase pathways modulated by the agonists sphingosine-1 phosphate (S1P) and vascular endothelial growth factor (VEGF). siRNA-mediated caveolin-1 knockdown enhanced basal as well as S1P- and VEGF-induced phosphorylation of the protein kinase Akt and did not modify the basal or agonist-induced phosphorylation of extracellular signal-regulated kinases 1/2. Caveolin-1 knock-down also significantly enhanced the basal and agonist-induced activity of the small GTPase Rac. We used siRNA to down-regulate Rac expression in BAEC, and we observed that Rac knockdown significantly reduced basal, S1P-, and VEGF-induced Akt phosphorylation, suggesting a role for Rac activation in the caveolin siRNA-mediated increase in Akt phosphorylation. By using siRNA to knockdown caveolin-1 and Rac expression in cultured endothelial cells, we have found that caveolin-1 does not seem to be required for the targeting of signaling molecules to caveolae/lipid rafts and that caveolin-1 differentially modulates specific kinase pathways in

  17. Cytosolic glucocorticoid receptor in the testis of Bufo arenarum: seasonal changes in its binding parameters.

    PubMed

    Denari, Daniela; Ceballos, Nora R

    2006-07-01

    Glucocorticoids (GC) are the hormonal mediators of stress. In mammals, high levels of GC have negative effects on reproductive physiology. For instance, GC can inhibit testicular testosterone synthesis by acting via glucocorticoid receptors (GR), the extent of the inhibition being dependent on GC levels. However, the effect of GC on testicular function and even the presence of GR in amphibians are still unclear. The purpose of this work was to characterise testicular cytosolic GR in Bufo arenarum, determining the seasonal changes in its binding parameters as well as the intratesticular localisation. The binding assays were performed in testis cytosol with [3H]dexamethasone (DEX) and [3H]corticosterone (CORT). Binding kinetics of DEX and CORT fitted to a one-site model. Results were expressed as means +/- standard error. Apparent number of binding sites (Bapp) was similar for both steroids (Bapp DEX = 352.53 +/- 72.08 fmol/mg protein; Bapp CORT = 454.24 +/- 134.97 fmol/mg protein) suggesting that both hormones bind to the same site. Competition studies with different steroids showed that the order of displacement of [3H]DEX and [3H]CORT specific binding is: DEX approximately RU486 approximately deoxycorticosterone (DOC) > CORT > aldosterone > RU28362 > progesterone > 11-dehydroCORT. The affinity of GR for DEX (Kd = 11.2 +/- 1.5 nM) remained constant throughout the year while circulating CORT clearly increased during the reproductive season. Therefore, testis sensitivity to GC action would depend mainly on inactivating mechanisms (11beta-hydroxysteroid dehydrogenase type 2) and CORT plasma levels. Since total and free CORT are higher in the reproductive than in the non-reproductive period, the magnitude of GC actions could be higher during the breeding season. The intratesticular localisation of the GR was determined after separation of cells by a Percoll density gradient followed by binding assays in each fraction. DEX binds to two different fractions corresponding

  18. Glucocorticoid-dependent induction of interleukin-6 receptor expression in human hepatocytes facilitates interleukin-6 stimulation of amino acid transport.

    PubMed

    Fischer, C P; Bode, B P; Takahashi, K; Tanabe, K K; Souba, W W

    1996-05-01

    The authors studied the effects of interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha) on glutamine and alanine transport in isolated human hepatocytes. They also evaluated the role of dexamethasone in modulating this response and its effects on the expression of the plasma membrane high-affinity IL-6 receptor. Animal studies indicate that cytokines are important mediators of the increased hepatic amino acid uptake that occurs during cancer and sepsis, but studies in human tissues are lacking. The control of transport by cytokines and cytokine receptor expression in the liver may provide a mechanism by which hepatocytes can modulate amino acid availability during catabolic disease states. Human hepatocytes were isolated from wedge biopsy specimens and plated in 24-well trays. Interleukin-6 and TNF-alpha, in combination with the synthetic glucocorticoid dexamethasone, were added to hepatocytes in culture, and the transport of radiolabeled glutamine and alanine was measured. Fluorescent-activated cell sorter (FACS) analysis was used to study the effects of dexamethasone on IL-6 receptor number in the well-differentiated human hepatoma HepG2. Both IL-6 and TNF-alpha exerted a small stimulatory effect on alanine and glutamine transport. Dexamethasone alone did not alter transport rates, but pretreatment of cells augmented the effects of both cytokines on carrier-mediated amino acid uptake. Dexamethasone pretreatment and a combination of IL-6 and TNF-alpha resulted in a greater than twofold increase in transport activity. Fluorescent-activated cell sorter analysis demonstrated that dexamethasone induced a threefold increase in the expression of high-affinity IL-6 receptors. Interleukin-6 and TNF-alpha work coordinately with glucocorticoids to stimulate amino acid uptake in human hepatocytes. Dexamethasone exerts a permissive effect on cytokine-mediated increases in transport by increasing IL-6 receptor expression on the cell surface. It is likely that this

  19. Pull-down Assay to Characterize Ca2+/Calmodulin Binding to Plant Receptor Kinases.

    PubMed

    Kaufmann, Christine; Sauter, Margret

    2017-01-01

    Plant receptor-like kinases (RLKs) are regulated by posttranscriptional modification and by interaction with regulatory proteins. A common modification of RLKs is (auto)phosphorylation, and a common regulatory protein is the calcium sensor calmodulin (CaM). We have developed protocols to detect the interaction of an RLK with CaM. The interaction with CaM was shown by bimolecular fluorescence complementation (BiFC) (see Chapter 14) and pull-down assay (this chapter). Both methods offer unique advantages. BiFC is useful in showing interaction of soluble as well as of membrane-bound proteins in planta. Pull-down assays are restricted to soluble proteins and provide in vitro data. The pull-down assay provides the advantage that proteins can be modified prior to binding and that experimental conditions such as the concentration of Ca 2+ or other divalent cations can be controlled. This chapter provides a pull-down protocol to study RLK-CaM interaction with optional steps to investigate the impact of RLK phosphorylation or of Ca 2+ .

  20. Optimal Down Regulation of mRNA Translation

    NASA Astrophysics Data System (ADS)

    Zarai, Yoram; Margaliot, Michael; Tuller, Tamir

    2017-01-01

    Down regulation of mRNA translation is an important problem in various bio-medical domains ranging from developing effective medicines for tumors and for viral diseases to developing attenuated virus strains that can be used for vaccination. Here, we study the problem of down regulation of mRNA translation using a mathematical model called the ribosome flow model (RFM). In the RFM, the mRNA molecule is modeled as a chain of n sites. The flow of ribosomes between consecutive sites is regulated by n + 1 transition rates. Given a set of feasible transition rates, that models the outcome of all possible mutations, we consider the problem of maximally down regulating protein production by altering the rates within this set of feasible rates. Under certain conditions on the feasible set, we show that an optimal solution can be determined efficiently. We also rigorously analyze two special cases of the down regulation optimization problem. Our results suggest that one must focus on the position along the mRNA molecule where the transition rate has the strongest effect on the protein production rate. However, this rate is not necessarily the slowest transition rate along the mRNA molecule. We discuss some of the biological implications of these results.

  1. Profile of the intestinal mucosal corticosteroid receptors in the domestic duck

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    DiBattista, J.A.; Mehdi, A.Z.; Sandor, T.

    The corticosteroid receptor profile of the intestinal tract of the domestic duck (maintained on either a low-sodium (LS) or a high-sodium (HS) diet) was investigated. Using tritiated triamcinolone acetonide (TA), corticosterone, or aldosterone as ligands, cytoplasmic mineralocorticoid receptors (MR, type I) and glucocorticoid receptors (GR, type II) were found in the mucosal cytosol of the jejunum and colon. The diet little influenced the GR binding parameters, while the MR (aldosterone) binding parameters showed a down-regulation following LS diets. The competition hierarchy of radioinert steroids on the formation of the (TH)corticosterone-receptor complex was corticosterone = cortisol = 11-deoxycorticosterone greater than aldosteronemore » = TA = dexamethasone much greater than 11-deoxycortisol; with (TH)aldosterone, the competition was corticosterone = progesterone = 11-deoxycorticosterone greater than aldosterone = cortisol = TA = dexamethasone greater than 11-deoxycortisol greater than 11-dehydrocorticosterone. On linear sucrose gradients, receptor-ligand complexes sedimented with a single peak at 8.5 S (hypotonic gradient) and 4.0-4.5 S (hypertonic gradient), respectively. Heat-activated (TH)TA- and (TH)aldosterone-receptor complexes bound avidly to DNA-cellulose and, upon ion-exchange chromatography on DEAE-Sephacel, the presence of the negatively charged unactivated and the more positively charged activated complexes could be shown.« less

  2. 15-Deoxy-{delta}{sup 12,14}-prostaglandin J{sub 2} down-regulates CXCR4 on carcinoma cells through PPAR{gamma}- and NF{kappa}B-mediated pathways

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Richard, Cynthia Lee; Lowthers, Erica Lauren; Blay, Jonathan

    2007-10-01

    The chemokine receptor CXCR4 plays a key role in the metastasis of colorectal cancer and its growth at metastatic sites. Here, we have investigated the mechanisms by which CXCR4 on cancer cells might be regulated by eicosanoids present within the colorectal tumor microenvironment. We show that prostaglandins PGE{sub 2}, PGA{sub 2}, PGD{sub 2}, PGJ{sub 2} and 15dPGJ{sub 2} each down-regulates CXCR4 receptor expression on human colorectal carcinoma cells to differing degrees. The most potent of these were PGD{sub 2} and its metabolites PGJ{sub 2} and 15dPGJ{sub 2}. Down-regulation was most rapid with the end-product 15dPGJ{sub 2} and was accompanied bymore » a marked reduction in CXCR4 mRNA. 15dPGJ{sub 2} is known to be a ligand for the nuclear receptor PPAR{gamma}. Down-regulation of CXCR4 was also observed with the PPAR{gamma} agonist rosiglitazone, while 15dPGJ{sub 2}-induced CXCR4 down-regulation was substantially diminished by the PPAR{gamma} antagonists GW9662 and T0070907. These data support the involvement of PPAR{gamma}. However, the 15dPGJ{sub 2} analogue CAY10410, which can act on PPAR{gamma} but which lacks the intrinsic cyclopentenone structure found in 15dPGJ{sub 2}, down-regulated CXCR4 substantially less potently than 15dPGJ{sub 2}. The cyclopentenone grouping is known to inhibit the activity of NF{kappa}B. Consistent with an additional role for NF{kappa}B, we found that the cyclopentenone prostaglandin PGA{sub 2} and cyclopentenone itself could also down-regulate CXCR4. Immunolocalization studies showed that the cellular context was sufficient to trigger a focal nuclear pattern of NF{kappa}B p50 and that 15dPGJ{sub 2} interfered with this p50 nuclear localization. These data suggest that 15dPGJ{sub 2} can down-regulate CXCR4 on cancer cells through both PPAR{gamma} and NF{kappa}B. 15dPGJ{sub 2}, present within the tumor microenvironment, may act to down-regulate CXCR4 and impact upon the overall process of tumor expansion.« less

  3. Increase of glucocorticoid receptor expression after environmental enrichment: relations to spatial memory, exploration and anxiety-related behaviors.

    PubMed

    Sampedro-Piquero, P; Begega, A; Arias, J L

    2014-04-22

    Environmental enrichment (EE) produces a remarkable degree of structural and functional plasticity in the hippocampus and possible mediators of these changes, such as glucocorticoid receptors (GRs), are of considerable interest. GRs are richly expressed in the hippocampus and they are involved in the adaptation to stressors and facilitate active coping in anxious situations. In this study, we assessed the effect of an EE protocol (24h/day during 69days) in adult Wistar rats on the activity in the elevated-zero maze (EZM), performance in the holeboard task (HB) and we also examined the changes in the glucocorticoid receptors (GRs) expression in the dorsal hippocampus (CA1, CA3 and DG). Our EE protocol reduced anxious behaviors in the EZM, so the animals spent more time and made more entries into the open sections. In the HB task, the enriched group showed more explorative behavior, a reduction of anxiety-related behaviors and a better cognitive performance compared to non-enriched animals. With regard to the GR expression, the EE condition produced an increase in the number of immunopositive cells for GRs in CA1, CA3 and DG. These results suggest that the better performance of enriched animals could be mediated in part by the increase of GRs in the dorsal hippocampus, which may alter the hippocampal neuronal function and accordingly, the anxiety levels, the spatial memory performance and the exploration levels in these animals. Copyright © 2014 Elsevier Inc. All rights reserved.

  4. Bile Acids Down-Regulate Caveolin-1 in Esophageal Epithelial Cells through Sterol Responsive Element-Binding Protein

    PubMed Central

    Prade, Elke; Tobiasch, Moritz; Hitkova, Ivana; Schäffer, Isabell; Lian, Fan; Xing, Xiangbin; Tänzer, Marc; Rauser, Sandra; Walch, Axel; Feith, Marcus; Post, Stefan; Röcken, Christoph; Schmid, Roland M.; Ebert, Matthias P.A.

    2012-01-01

    Bile acids are synthesized from cholesterol and are major risk factors for Barrett adenocarcinoma (BAC) of the esophagus. Caveolin-1 (Cav1), a scaffold protein of membrane caveolae, is transcriptionally regulated by cholesterol via sterol-responsive element-binding protein-1 (SREBP1). Cav1 protects squamous epithelia by controlling cell growth and stabilizing cell junctions and matrix adhesion. Cav1 is frequently down-regulated in human cancers; however, the molecular mechanisms that lead to this event are unknown. We show that the basal layer of the nonneoplastic human esophageal squamous epithelium expressed Cav1 mainly at intercellular junctions. In contrast, Cav1 was lost in 95% of tissue specimens from BAC patients (n = 100). A strong cytoplasmic expression of Cav1 correlated with poor survival in a small subgroup (n = 5) of BAC patients, and stable expression of an oncogenic Cav1 variant (Cav1-P132L) in the human BAC cell line OE19 promoted proliferation. Cav1 was also detectable in immortalized human squamous epithelial, Barrett esophagus (CPC), and squamous cell carcinoma cells (OE21), but was low in BAC cell lines (OE19, OE33). Mechanistically, bile acids down-regulated Cav1 expression by inhibition of the proteolytic cleavage of 125-kDa pre-SREBP1 from the endoplasmic reticulum/Golgi apparatus and nuclear translocation of active 68-kDa SREBP1. This block in SREBP1's posttranslational processing impaired transcriptional activation of SREBP1 response elements in the proximal human Cav1 promoter. Cav1 was also down-regulated in esophagi from C57BL/6 mice on a diet enriched with 1% (wt/wt) chenodeoxycholic acid. Mice deficient for Cav1 or the nuclear bile acid receptor farnesoid X receptor showed hyperplasia and hyperkeratosis of the basal cell layer of esophageal epithelia, respectively. These data indicate that bile acid-mediated down-regulation of Cav1 marks early changes in the squamous epithelium, which may contribute to onset of Barrett esophagus

  5. Org 214007-0: A Novel Non-Steroidal Selective Glucocorticoid Receptor Modulator with Full Anti-Inflammatory Properties and Improved Therapeutic Index

    PubMed Central

    Laskewitz, Anke J.; Dijkema, Rein; van der Maaden, Hans M.; Smit, Martin J.; Plate, Ralf; Conti, Paolo G. M.; Jans, Christan G. J. M.; Timmers, C. Marco; van Boeckel, Constant A. A.; Lusher, Scott J.; McGuire, Ross; van Schaik, Rene C.; de Vlieg, Jacob; Smeets, Ruben L.; Hofstra, Claudia L.; Boots, Annemieke M. H.; van Duin, Marcel; Ingelse, Benno A.; Schoonen, Willem G. E. J.; Grefhorst, Aldo; van Dijk, Theo H.; Kuipers, Folkert; Dokter, Wim H. A.

    2012-01-01

    Glucocorticoids (GCs) such as prednisolone are potent immunosuppressive drugs but suffer from severe adverse effects, including the induction of insulin resistance. Therefore, development of so-called Selective Glucocorticoid Receptor Modulators (SGRM) is highly desirable. Here we describe a non-steroidal Glucocorticoid Receptor (GR)-selective compound (Org 214007-0) with a binding affinity to GR similar to that of prednisolone. Structural modelling of the GR-Org 214007-0 binding site shows disturbance of the loop between helix 11 and helix 12 of GR, confirmed by partial recruitment of the TIF2-3 peptide. Using various cell lines and primary human cells, we show here that Org 214007-0 acts as a partial GC agonist, since it repressed inflammatory genes and was less effective in induction of metabolic genes. More importantly, in vivo studies in mice indicated that Org 214007-0 retained full efficacy in acute inflammation models as well as in a chronic collagen-induced arthritis (CIA) model. Gene expression profiling of muscle tissue derived from arthritic mice showed a partial activity of Org 214007-0 at an equi-efficacious dosage of prednisolone, with an increased ratio in repression versus induction of genes. Finally, in mice Org 214007-0 did not induce elevated fasting glucose nor the shift in glucose/glycogen balance in the liver seen with an equi-efficacious dose of prednisolone. All together, our data demonstrate that Org 214007-0 is a novel SGRMs with an improved therapeutic index compared to prednisolone. This class of SGRMs can contribute to effective anti-inflammatory therapy with a lower risk for metabolic side effects. PMID:23152771

  6. Hormetic effects by exercise on hippocampal neurogenesis with glucocorticoid signaling

    PubMed Central

    Okamoto, Masahiro; Yamamura, Yuhei; Liu, Yu-Fan; Min-Chul, Lee; Matsui, Takashi; Shima, Takeru; Soya, Mariko; Takahashi, Kanako; Soya, Shingo; McEwen, Bruce S.; Soya, Hideaki

    2015-01-01

    Abstract Exercise enhances adult hippocampal neurogenesis (AHN), although the exact nature of how this happens remains controversial. The beneficial effects of exercise vary depending upon the exercise condition, especially intensity. Most animal studies, however, have used wheel running, which only evaluates running distance (exercise volume) and does not consider intensity. In our rat model, we have found that exercise-induced neurogenesis varies depending on the intensity of the exercise and have found that exercise-enhanced neurogenesis is more pronounced with mild exercise than with moderate and/or intense exercise. This may be due, at least in part, to increased glucocorticoid (CORT) secretion. To test this hypothesis, we used our special exercise model in mice, with and without a stress response, based on the lactate threshold (LT) in which moderate exercise above the LT increases lactate and adrenocorticotropic hormone (ACTH) release, while mild exercise does not. Adult male C57BL/6J mice were subjected to two weeks of exercise training and AHN was measured with a 5-Bromo-2-deoxyuridine (BrdU) pre-injection and immunohistochemistry. The role of glucocorticoid signaling was examined using intrapertioneal injections of antagonists for the glucocorticoid receptor (GR), mifepristone, and the mineralocorticoid receptor (MR), spironolactone. We found that, while mild exercise increased AHN without elevating CORT blood levels, both MR and GR antagonists abolished mild-exercise-induced AHN, but did not affect AHN under intense exercise. This suggests a facilitative, permissive role of glucocorticoid and mineralocorticoid receptors in AHN during mild exercise (234/250)

  7. Maternal distress associates with placental genes regulating fetal glucocorticoid exposure and IGF2: Role of obesity and sex.

    PubMed

    Mina, Theresia H; Räikkönen, Katri; Riley, Simon C; Norman, Jane E; Reynolds, Rebecca M

    2015-09-01

    Maternal emotional distress symptoms, including life satisfaction, anxiety and depressed mood, are worse in Severely Obese (SO) than lean pregnancy and may alter placental genes regulating fetal glucocorticoid exposure and placental growth. We hypothesised that the associations between increased maternal distress symptoms and changes in placental gene expression including IGF2 and genes regulating fetal glucocorticoid exposure are more pronounced in SO pregnancy. We also considered whether there were sex-specific effects. Placental mRNA levels of 11β-HSDs, NR3C1-α, NR3C2, ABC transporters, mTOR and the IGF2 family were measured in term placental samples from 43 lean (BMI≤25kg/m(2)) and 50 SO (BMI≥40kg/m(2)) women, in whom distress symptoms were prospectively evaluated during pregnancy. The mRNA levels of genes with a similar role in regulating fetal glucocorticoid exposure were strongly inter-correlated. Increased maternal distress symptoms associated with increased NR3C2 and IGF2 isoform 1(IGF2-1) in both lean and SO group (p≤0.05). Increased distress was associated with higher ABCB1 and ABCG2 mRNA levels in SO but lower ABCB1 and higher 11β-HSD1 mRNA levels in lean (p≤0.05) suggesting a protective adaptive response in SO placentas. Increased maternal distress associated with reduced mRNA levels of ABCB1, ABCG2, 11β-HSD2, NR3C1-α and IGF2-1 in placentas of female but not male offspring. The observed sex differences in placental responses suggest greater vulnerability of female fetuses to maternal distress with potentially greater fetal glucocorticoid exposure and excess IGF2. Further studies are needed to replicate these findings and to test whether this translates to potentially greater negative outcomes of maternal distress in female offspring in early childhood. Copyright © 2015 Elsevier Ltd. All rights reserved.

  8. The emerging importance of ultradian glucocorticoid rhythms within metabolic pathology.

    PubMed

    Flynn, Benjamin P; Conway-Campbell, Becky L; Lightman, Stafford L

    2018-06-01

    Glucocorticoid (GC) hormones play significant roles within homeostasis and the chrono-dynamics of their regulatory role has become increasingly recognised within dysregulated GC pathology, particularly with metabolic phenotypes. Within this article, we will discuss the relevance of the ultradian homeostatic rhythm, how its dysregulation effects glucocorticoid receptor and RNA polymeraseII recruitment and may play a significant role within aberrant metabolic action. Copyright © 2018 The Authors. Published by Elsevier Masson SAS.. All rights reserved.

  9. The Progestin-Only Contraceptive Medroxyprogesterone Acetate, but Not Norethisterone Acetate, Enhances HIV-1 Vpr-Mediated Apoptosis in Human CD4+ T Cells through the Glucocorticoid Receptor

    PubMed Central

    Tomasicchio, Michele; Avenant, Chanel; Du Toit, Andrea; Ray, Roslyn M.; Hapgood, Janet P.

    2013-01-01

    The glucocorticoid receptor (GR) regulates several physiological functions, including immune function and apoptosis. The HIV-1 virus accessory protein, viral protein R (Vpr), can modulate the transcriptional response of the GR. Glucocorticoids (GCs) and Vpr have been reported to induce apoptosis in various cells, including T-cells. We have previously shown that the injectable contraceptive, medroxyprogesterone acetate (MPA) is a partial to full agonist for the GR, unlike norethisterone acetate (NET-A). We investigated the functional cross talk between the GR and Vpr in inducing apoptosis in CD4+ T-cells, in the absence and presence of GCs and these progestins, as well as progesterone. By using flow cytometry, we show that, in contrast to NET-A and progesterone, the synthetic GR ligand dexamethasone (Dex), cortisol and MPA induce apoptosis in primary CD4+ T-cells. Furthermore, the C-terminal part of the Vpr peptide, or HIV-1 pseudovirus, together with Dex or MPA further increased the apoptotic phenotype, unlike NET-A and progesterone. By a combination of Western blotting, PCR and the use of receptor- selective agonists, we provide evidence that the GR and the estrogen receptor are the only steroid receptors expressed in peripheral blood mononuclear cells. These results, together with the findings that RU486, a GR antagonist, prevents Dex-, MPA- and Vpr-mediated apoptosis, provide evidence for the first time that GR agonists or partial agonists increase apoptosis in primary CD4+ T-cells via the GR. We show that apoptotic induction involves differential expression of key apoptotic genes by both Vpr and GCs/MPA. This work suggests that contraceptive doses of MPA but not NET-A or physiological doses of progesterone could potentially accelerate depletion of CD4+ T-cells in a GR-dependent fashion in HIV-1 positive women, thereby contributing to immunodeficiency. The results imply that choice of progestin used in contraception may be critical to susceptibility and

  10. Carolinas SETAC: Validation of a Glucocorticoid Receptor Effects-Based Environmental Sample Screening Tool

    EPA Science Inventory

    Glucocorticoid activity has been detected, using in vitro effects-based monitoring tools (e.g. transcriptional activation bioassays), in waste and surface waters domestically and around the world. A review of the existing literature confirms that many different glucocorticoid rec...

  11. Effect of the glucocorticoid receptor antagonist Org 34850 on fast and delayed feedback of corticosterone release.

    PubMed

    Spiga, Francesca; Harrison, Louise R; Wood, Susan A; MacSweeney, Cliona P; Thomson, Fiona J; Craighead, Mark; Grassie, Morag; Lightman, Stafford L

    2008-02-01

    We investigated the effect of the glucocorticoid receptor (GR) antagonist Org 34850 on fast and delayed inhibition of corticosterone secretion in response to the synthetic glucocorticoid methylprednisolone (MPL). Male rats were implanted with a catheter in the right jugular vein, for blood sampling and MPL administration, and with an s.c. cannula for Org 34850 administration. All experiments were conducted at the diurnal hormonal peak in the late afternoon. Rats were connected to an automated sampling system and blood samples were collected every 5 or 10 min. Org 34850 (10 mg/kg, s.c.) or vehicle (5% mulgofen in saline) was injected at 1630 h; 30 min later, rats received an injection of MPL (500 microg/rat, i.v.) or saline (0.1 ml/rat). We found that an acute administration of MPL rapidly decreased the basal corticosterone secretion and this effect was not prevented by acute pretreatment with Org 34850. However, blockade of GR with Org 34850 prevented delayed inhibition of MPL on corticosterone secretion measured between 4 and 12 h after MPL administration. Our data suggest an involvement of GR in modulating delayed, but not fast, inhibition induced by MPL on basal corticosterone secretion.

  12. nAChRs-ERK1/2-Egr-1 signaling participates in the developmental toxicity of nicotine by epigenetically down-regulating placental 11β-HSD2.

    PubMed

    Zhou, Jin; Liu, Fulin; Yu, Luting; Xu, Dan; Li, Bin; Zhang, Guohui; Huang, Wen; Li, Lu; Zhang, Yuanzhen; Zhang, Wei; Wang, Hui

    2018-04-01

    Impaired placental 11β-hydroxysteroid dehydrogenase type 2 (11β-HSD2) activity which inactivates maternal glucocorticoids is associated with poor fetal growth and a higher risk of chronic diseases in adulthood. This study aimed to elucidate the epigenetically regulatory mechanism of nicotine on placental 11β-HSD2 expression. Pregnant Wistar rats were administered 1.0 mg/kg nicotine subcutaneously twice a day from gestational day 9 to 20. The results showed that prenatal nicotine exposure increased corticosterone levels in the placenta and fetal serum, disrupted placental morphology and endocrine function, and reduced fetal bodyweight. Meanwhile, histone modification abnormalities (decreased acetylation and increased di-methylation of histone 3 Lysine 9) on the HSD11B2 promoter and lower-expression of 11β-HSD2 were observed. Furthermore, the expression of nicotinic acetylcholine receptor (nAChR) α4/β2, the phosphorylation of extracellular regulated kinase 1/2 (ERK1/2) and Ets-like protein-1 (Elk-1), and the expression of early growth response-1 (Egr-1) were increased in the nicotine groups. In human BeWo cells, nicotine decreased 11β-HSD2 expression, increased nAChRα9 expression, and activated ERK1/2/Elk-1/Egr-1 signaling in the concentration (0.1-10 μM)-dependent manner. Antagonism of nAChRs, inhibition of ERK1/2 and Egr-1 knockdown by siRNA were able to block/abrogate the effects of nicotine on histone modification and expression of 11β-HSD2. Taken together, nicotine can impair placental structure and function, and induce fetal developmental toxicity. The underlying mechanism involves histone modifications and down-regulation of 11β-HSD2 through nAChRs/ERK1/2/Elk-1/Egr-1 signaling, which increases active glucocorticoids levels in the placenta and fetus, and eventually inhibits the fetal development. Copyright © 2018 Elsevier Inc. All rights reserved.

  13. Estradiol stimulates an anti-translocation expression pattern of glucocorticoid co-regulators in a hippocampal cell model

    PubMed Central

    Malviya, Sanjana A.; Kelly, Sean D.; Greenlee, Megan M.; Eaton, Douglas C.; Duke, Billie Jeanne; Bourke, Chase H.; Neigh, Gretchen N.

    2013-01-01

    A consistent clinical finding in patients with major depressive disorder (MDD) is hyperactivity of the hypothalamic–pituitary–adrenal (HPA) axis, the system in the body that facilitates the response to stress. It has been suggested that alterations in glucocorticoid receptor (GR)-mediated feedback prolong activation of the HPA axis, leading to the dysfunction observed in MDD. Additionally, the risk for developing MDD is heightened by several risk factors, namely gender, genetics and early life stress. Previous studies have demonstrated that GR translocation is sexually dimorphic and this difference may be facilitated by differential expression of GR co-regulators. The purpose of this study was to determine the extent to which ovarian hormones alter expression of GR and its co-regulators, Fkbp5 and Ppid, in HT-22 hippocampal neurons. The impact of corticosterone (cort), estradiol (E2), and progesterone (P4) treatments on the expression of the genes Nr3c1, Ppid, and Fkbp5 was assessed in HT-22 hippocampal neurons. Treatment of cells with increasing doses of cort increased the expression of Fkbp5, an effect that was potentiated by E2. Exposure of HT-22 cells to E2 decreased the expression of Ppid and simultaneous exposure to E2 and P4 had combinatory effects on Ppid expression. The effects of E2 on Ppid extend previous work which demonstrated that serum E2 concentrations correlate with hippocampal Ppid expression in female rats. The results presented here illustrate that E2 generates an anti-translocation pattern of GR co-regulators in hippocampal cells. PMID:23541378

  14. Genes down-regulated in spaceflight are involved in the control of longevity in Caenorhabditis elegans.

    PubMed

    Honda, Yoko; Higashibata, Akira; Matsunaga, Yohei; Yonezawa, Yukiko; Kawano, Tsuyoshi; Higashitani, Atsushi; Kuriyama, Kana; Shimazu, Toru; Tanaka, Masashi; Szewczyk, Nathaniel J; Ishioka, Noriaki; Honda, Shuji

    2012-01-01

    How microgravitational space environments affect aging is not well understood. We observed that, in Caenorhabditis elegans, spaceflight suppressed the formation of transgenically expressed polyglutamine aggregates, which normally accumulate with increasing age. Moreover, the inactivation of each of seven genes that were down-regulated in space extended lifespan on the ground. These genes encode proteins that are likely related to neuronal or endocrine signaling: acetylcholine receptor, acetylcholine transporter, choline acetyltransferase, rhodopsin-like receptor, glutamate-gated chloride channel, shaker family of potassium channel, and insulin-like peptide. Most of them mediated lifespan control through the key longevity-regulating transcription factors DAF-16 or SKN-1 or through dietary-restriction signaling, singly or in combination. These results suggest that aging in C. elegans is slowed through neuronal and endocrine response to space environmental cues.

  15. Genes down-regulated in spaceflight are involved in the control of longevity in Caenorhabditis elegans

    PubMed Central

    Honda, Yoko; Higashibata, Akira; Matsunaga, Yohei; Yonezawa, Yukiko; Kawano, Tsuyoshi; Higashitani, Atsushi; Kuriyama, Kana; Shimazu, Toru; Tanaka, Masashi; Szewczyk, Nathaniel J.; Ishioka, Noriaki; Honda, Shuji

    2012-01-01

    How microgravitational space environments affect aging is not well understood. We observed that, in Caenorhabditis elegans, spaceflight suppressed the formation of transgenically expressed polyglutamine aggregates, which normally accumulate with increasing age. Moreover, the inactivation of each of seven genes that were down-regulated in space extended lifespan on the ground. These genes encode proteins that are likely related to neuronal or endocrine signaling: acetylcholine receptor, acetylcholine transporter, choline acetyltransferase, rhodopsin-like receptor, glutamate-gated chloride channel, shaker family of potassium channel, and insulin-like peptide. Most of them mediated lifespan control through the key longevity-regulating transcription factors DAF-16 or SKN-1 or through dietary-restriction signaling, singly or in combination. These results suggest that aging in C. elegans is slowed through neuronal and endocrine response to space environmental cues. PMID:22768380

  16. The stimulus-dependent co-localization of serum- and glucocorticoid-regulated protein kinase (Sgk) and Erk/MAPK in mammary tumor cells involves the mutual interaction with the importin-alpha nuclear import protein

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Buse, Patricia; Maiyar, Anita C.; Failor, Kim L.

    2007-09-10

    In Con8 rat mammary epithelial tumor cells, indirect immunofluorescence revealed that Sgk (serum- and glucocorticoid-regulated kinase) and Erk/MAPK (extracellular signal-regulated protein kinase/mitogen activated protein kinase) co-localized to the nucleus in serum-treated cells and to the cytoplasmic compartment in cells treated with the synthetic glucocorticoid dexamethasone. Moreover, the subcellular distribution of the importin-alpha nuclear transport protein was similarly regulated in a signal-dependent manner. In vitro GST-pull down assays revealed the direct interaction of importin-alpha with either Sgk or Erk/MAPK, while RNA interference knockdown of importin-alpha expression disrupted the localization of both Sgk and Erk into the nucleus of serum-treated cells. Wildmore » type or kinase dead forms of Sgk co-immunoprecipitated with Erk/MAPK from either serum- or dexamethasone-treated mammary tumor cells, suggesting the existence of a protein complex containing both kinases. In serum-treated cells, nucleus residing Sgk and Erk/MAPK were both hyperphosphorylated, indicative of their active states, whereas, in dexamethasone-treated cells Erk/MAPK, but not Sgk, was in its inactive hypophosphorylated state. Treatment with a MEK inhibitor, which inactivates Erk/MAPK, caused the relocalization of both Sgk and ERK to the cytoplasm. We therefore propose that the signal-dependent co-localization of Sgk and Erk/MAPK mediated by importin-alpha represents a new pathway of signal integration between steroid and serum/growth factor-regulated pathways.« less

  17. Adverse parenting is associated with blunted salivary cortisol awakening response and altered expression of glucocorticoid receptor β and β2-adrenergic receptor mRNAs in leukocytes in Japanese medical students.

    PubMed

    Kawai, Tomoko; Kuwano, Yuki; Masuda, Kiyoshi; Fujita, Kinuyo; Tanaka, Hiroki; Nishikawa, Tatsuya; Rokutan, Kazuhito; Nishida, Kensei

    2017-03-01

    Adverse parenting is associated with an increased risk for the development of mood and behavioral disorders. In this study, we assessed the perceived parental bonding of 232 medical students using the parental bonding instrument (PBI) and extracted 22 students who reported their parents' rearing attitudes as affectionless control (LOW; low care, high overprotection). Using the 28-item general health questionnaire, the Zung self-rating depression scale (Zung-SDS), the hospital anxiety and depression scale (HADS), and the Spielberger state-trait-anxiety-inventory (STAI), physical and mental state of the LOW students were compared with those of 30 students who reported their parental bonding as optimal (OPT; high care and low overprotection). These questionnaire measurements demonstrated significantly higher anxiety and depressive mood in the LOW students versus the OPT students. Compared with the OPT students, the LOW students also exhibited a significantly reduced salivary cortisol awakening response (CAR) without changes across the rest of the diurnal salivary cortisol profile. Among glucocorticoid-related genes examined (GR, ADRB2, IκBα, IL10, IL1R2, IL1RN, MR, MC2R, TGFB1, TGFB2 and FASLG), real-time reverse transcription-PCR showed that the LOW students significantly increased expression of a dominant negative glucocorticoid receptor β (GRβ) mRNA and decreased β2-adrenergic receptor (ADRB2) mRNA levels in circulating leukocytes. These results suggest that negative perception of parents' child-rearing attitudes may be associated with anxiety and depressive mood and altered glucocorticoid signaling even in healthy young adults.

  18. Glucocorticoid-induced pancreatic-hepatic trans-differentiation in a human cell line in vitro.

    PubMed

    Fairhall, Emma A; Leitch, Alistair C; Lakey, Anne F; Probert, Philip M E; Richardson, Gabriella; De Santis, Carol; Wright, Matthew C

    2018-05-22

    The rodent pancreatic AR42J-B13 (B-13) cell line differentiates into non-replicative hepatocyte-like cells in response to glucocorticoid mediated via the glucocorticoid receptor (GR). The aims of this study were to identify a human cell line that responds similarly and investigate the mechanisms underpinning any alteration in differentiation. Exposing the human pancreatic adenocarcinoma (HPAC) cell line to 1-10 µM concentrations of dexamethasone (DEX) resulted an inhibition of proliferation, suppressed carcinoembryonic antigen expression, limited expression of pancreatic acinar and hepatic gene expression and significant induction of the constitutively-expressed hepatic CYP3A5 mRNA transcript. These changes were associated with a pulse of genomic DNA methylation and suppressed notch signalling activity. HPAC cells expressed high levels of GR transcript in contrast to other nuclear receptors - such as the glucocorticoid-activated pregnane X receptor (PXR) - and GR transcriptional function was activated by DEX in HPAC cells. Expression of selected hepatocyte transcripts in response to DEX was blocked by co-treatment with the GR antagonist RU486. These data indicate that the HPAC response to glucocorticoid exposure includes an inhibition in proliferation, alterations in notch signalling and a limited change in the expression of genes associated with an acinar and hepatic phenotype. This is the first demonstration of a human cell responding to similarly to the rodent B-13 cell regarding formation of hepatocyte-like cells in response to glucocorticoid. Identifying and modulating the ablating factor(s) may enhance the hepatocyte-like forming capacity of HPAC cells after exposure to glucocorticoid and generate an unlimited in vitro supply of human hepatocytes for toxicology studies and a variety of clinical applications. Copyright © 2018 International Society of Differentiation. Published by Elsevier B.V. All rights reserved.

  19. Estrogen-related receptor {alpha} modulates the expression of adipogenesis-related genes during adipocyte differentiation

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Ijichi, Nobuhiro; Ikeda, Kazuhiro; Horie-Inoue, Kuniko

    2007-07-06

    Estrogen-related receptor {alpha} (ERR{alpha}) is an orphan nuclear receptor that regulates cellular energy metabolism by modulating gene expression involved in fatty acid oxidation and mitochondrial biogenesis in brown adipose tissue. However, the physiological role of ERR{alpha} in adipogenesis and white adipose tissue development has not been well studied. Here, we show that ERR{alpha} and ERR{alpha}-related transcriptional coactivators, peroxisome proliferator-activated receptor {gamma} (PPAR{gamma}) coactivator-1{alpha} (PGC-1{alpha}) and PGC-1{beta}, can be up-regulated in 3T3-L1 preadipocytes at mRNA levels under the adipogenic differentiation condition including the inducer of cAMP, glucocorticoid, and insulin. Gene knockdown by ERR{alpha}-specific siRNA results in mRNA down-regulation of fatty acidmore » binding protein 4, PPAR{gamma}, and PGC-1{alpha} in 3T3-L1 cells in the adipogenesis medium. ERR{alpha} and PGC-1{beta} mRNA expression can be also up-regulated in another preadipocyte lineage DFAT-D1 cells and a pluripotent mesenchymal cell line C3H10T1/2 under the differentiation condition. Furthermore, stable expression of ERR{alpha} in 3T3-L1 cells up-regulates adipogenic marker genes and promotes triglyceride accumulation during 3T3-L1 differentiation. These results suggest that ERR{alpha} may play a critical role in adipocyte differentiation by modulating the expression of various adipogenesis-related genes.« less

  20. The enhancement of stress-related memory by glucocorticoids depends on synapsin-Ia/Ib

    PubMed Central

    Revest, J-M; Kaouane, N; Mondin, M; Le Roux, A; Rougé-Pont, F; Vallée, M; Barik, J; Tronche, F; Desmedt, A; Piazza, P V

    2010-01-01

    The activation of glucocorticoid receptors (GR) by glucocorticoids increases stress-related memory through the activation of the MAPK signaling pathway and the downstream transcription factor Egr-1. Here, using converging in vitro and in vivo approaches, respectively, GR-expressing cell lines, culture of hippocampal neurons, and GR genetically modified mice (GRNesCre), we identified synapsin-Ia/Ib as one of the effectors of the glucocorticoid signaling cascade. Stress and glucocorticoid-induced activation of the GR modulate synapsin-Ia/Ib through two complementary mechanisms. First, glucocorticoids driving Egr-1 expression increase the expression of synapsin-Ia/Ib, and second, glucocorticoids driving MAPK activation increase its phosphorylation. Finally, we showed that blocking fucosylation of synapsin-Ia/Ib in the hippocampus inhibits its expression and prevents the glucocorticoid-mediated increase in stress-related memory. In conclusion, our data provide a complete molecular pathway (GR/Egr-1/MAPK/Syn-Ia/Ib) through which stress and glucocorticoids enhance the memory of stress-related events and highlight the function of synapsin-Ia/Ib as molecular effector of the behavioral effects of stress. PMID:20368707

  1. Rapid corticosteroid-dependent regulation of mineralocorticoid receptor protein expression in rat brain.

    PubMed

    Kalman, Brian A; Spencer, Robert L

    2002-11-01

    Corticosteroid hormones regulate many aspects of neural function via mineralocorticoid receptors (MR) and glucocorticoid receptors (GR). Although GR expression is negatively regulated by endogenous corticosteroids, the autologous regulation of MR expression has been less well studied, partly due to limitations of receptor binding assays that cannot measure the ligand-activated form of MR. Using MR-reactive antibodies and Western blot, we examined relative MR protein expression in rat brain and its potential autoregulation by corticosteroids. We found that MR protein expression is autoregulated in a negative fashion by adrenal steroids. Compared with GR, we see a more rapid regulation of MR, such that there is a substantial increase in MR protein within 12 h after adrenalectomy, whereas GR levels show very little increase until more than 24 h after adrenalectomy. Also, in contrast to GR, which has been found to be regulated by both MR and GR, adrenalectomy-induced increase in MR was prevented by treatment with the MR selective agonist, aldosterone, but not the GR selective agonist, RU28362. Interestingly, acute treatment of adrenalectomized rats with corticosterone produced a significant decrease in whole-cell MR protein within 45 min, suggesting ligand-induced rapid degradation of MR. Chronic high levels of corticosterone also produced a significant decrease in MR protein levels below adrenal-intact rat levels. These results have important implications for previous studies that estimated the proportion of MR that are occupied in vivo by various circulating levels of corticosterone. Those studies compared available MR binding levels in adrenal-intact rats with 24-h adrenalectomized rats, with the assumption that there were no differences between the various conditions in total receptor expression. Those studies concluded that MR is nearly fully occupied by even the lowest circulating corticosterone levels. Given the 2- to 3-fold increase in MR protein that we have

  2. Serum and Glucocorticoid Regulated Kinase 1 (SGK1) Regulates Neutrophil Clearance During Inflammation Resolution

    PubMed Central

    Burgon, Joseph; Robertson, Anne L.; Sadiku, Pranvera; Wang, Xingang; Hooper-Greenhill, Edward; Prince, Lynne R.; Walker, Paul; Hoggett, Emily E.; Ward, Jonathan R.; Farrow, Stuart N.; Zuercher, William J.; Jeffrey, Philip; Savage, Caroline O.; Ingham, Philip W.; Hurlstone, Adam F.; Whyte, Moira K. B.; Renshaw, Stephen A.

    2013-01-01

    The inflammatory response is integral to maintaining health, by functioning to resist microbial infection and repair tissue damage. Large numbers of neutrophils are recruited to inflammatory sites to neutralise invading bacteria through phagocytosis and the release of proteases and reactive oxygen species into the extracellular environment. Removal of the original inflammatory stimulus must be accompanied by resolution of the inflammatory response, including neutrophil clearance, to prevent inadvertent tissue damage. Neutrophil apoptosis and its temporary inhibition by survival signals provides a target for anti-inflammatory therapeutics, making it essential to better understand this process. GM-CSF, a neutrophil survival factor, causes a significant increase in mRNA levels for the known anti-apoptotic protein Serum and Glucocorticoid Regulated Kinase 1 (SGK1). We have characterised the expression patterns and regulation of SGK family members in human neutrophils, and shown that inhibition of SGK activity completely abrogates the anti-apoptotic effect of GM-CSF. Using a transgenic zebrafish model, we have disrupted sgk1 gene function and shown this specifically delays inflammation resolution, without altering neutrophil recruitment to inflammatory sites in vivo. These data suggest SGK1 plays a key role in regulating neutrophil survival signalling, and thus may prove a valuable therapeutic target for the treatment of inflammatory disease. PMID:24431232

  3. Betacellulin induces Slug-mediated down-regulation of E-cadherin and cell migration in ovarian cancer cells

    PubMed Central

    Zhao, Jianfang; Klausen, Christian; Qiu, Xin; Cheng, Jung-Chien; Chang, Hsun-Ming; Leung, Peter C.K.

    2016-01-01

    Epithelial ovarian cancer is the leading cause of death among gynaecological cancers. Previous studies have demonstrated that epidermal growth factor receptor (EGFR) ligands can induce ovarian cancer cell invasion by down-regulating E-cadherin. Betacellulin is a unique member of the EGF family. It is overexpressed in a variety of cancers and is associated with reduced survival. However, the biological functions and clinical significance of betacellulin in ovarian cancer remain unknown. In the current study, we tested the hypothesis that betacellulin induces ovarian cancer cell migration by suppressing E-cadherin expression. Treatment of SKOV3 and OVCAR5 ovarian cancer cell lines with betacellulin down-regulated E-cadherin, but not N-cadherin. In addition, betacellulin treatment increased the expression of Snail and Slug, and these effects were completely blocked by pre-treatment with EGFR inhibitor AG1478. Interestingly, only knockdown of Slug reversed the down-regulation of E-cadherin by betacellulin. Betacellulin treatment induced the activation of both the MEK-ERK and PI3K-Akt signaling pathways, and it also significantly increased ovarian cancer cell migration. Importantly, the effects of betacellulin on E-cadherin, Slug and cell migration were attenuated by pre-treatment with either U0126 or LY294002. Our results suggest that betacellulin induces ovarian cancer migration and Slug-dependent E-cadherin down-regulation via EGFR-mediated MEK-ERK and PI3K-Akt signaling. PMID:27129169

  4. Multimodal Regulation of Circadian Glucocorticoid Rhythm by Central and Adrenal Clocks.

    PubMed

    Son, Gi Hoon; Cha, Hyo Kyeong; Chung, Sooyoung; Kim, Kyungjin

    2018-05-01

    Adrenal glucocorticoids (GCs) control a wide range of physiological processes, including metabolism, cardiovascular and pulmonary activities, immune and inflammatory responses, and various brain functions. During stress responses, GCs are secreted through activation of the hypothalamic-pituitary-adrenal axis, whereas circulating GC levels in unstressed states follow a robust circadian oscillation with a peak around the onset of the active period of a day. A recent advance in chronobiological research has revealed that multiple regulatory mechanisms, along with classical neuroendocrine regulation, underlie this GC circadian rhythm. The hierarchically organized circadian system, with a central pacemaker in the suprachiasmatic nucleus of the hypothalamus and local oscillators in peripheral tissues, including the adrenal gland, mediates periodicities in physiological processes in mammals. In this review, we primarily focus on our understanding of the circadian regulation of adrenal GC rhythm, with particular attention to the cooperative actions of the suprachiasmatic nucleus central and adrenal local clocks, and the clinical implications of this rhythm in human diseases.

  5. Multimodal Regulation of Circadian Glucocorticoid Rhythm by Central and Adrenal Clocks

    PubMed Central

    Son, Gi Hoon; Cha, Hyo Kyeong; Chung, Sooyoung; Kim, Kyungjin

    2018-01-01

    Abstract Adrenal glucocorticoids (GCs) control a wide range of physiological processes, including metabolism, cardiovascular and pulmonary activities, immune and inflammatory responses, and various brain functions. During stress responses, GCs are secreted through activation of the hypothalamic–pituitary–adrenal axis, whereas circulating GC levels in unstressed states follow a robust circadian oscillation with a peak around the onset of the active period of a day. A recent advance in chronobiological research has revealed that multiple regulatory mechanisms, along with classical neuroendocrine regulation, underlie this GC circadian rhythm. The hierarchically organized circadian system, with a central pacemaker in the suprachiasmatic nucleus of the hypothalamus and local oscillators in peripheral tissues, including the adrenal gland, mediates periodicities in physiological processes in mammals. In this review, we primarily focus on our understanding of the circadian regulation of adrenal GC rhythm, with particular attention to the cooperative actions of the suprachiasmatic nucleus central and adrenal local clocks, and the clinical implications of this rhythm in human diseases. PMID:29713692

  6. The vitamin D analogue paricalcitol attenuates hepatic ischemia/reperfusion injury through down-regulation of Toll-like receptor 4 signaling in rats

    PubMed Central

    Kim, Min Sung; Lee, Soyoung; Jung, Namhee; Lee, Kiho; Choi, Jinwoo; Kim, Sang-Hoon; Jun, Jinhyun; Lee, Won-Mee; Chang, Yeonsoo

    2016-01-01

    Introduction Recent studies have revealed that vitamin D and its synthetic analogues have a protective effect on experimental ischemia/reperfusion (I/R) models in several organs, but little is known about its effect on the liver. The aim of this study was to evaluate the beneficial effects of vitamin D in a model of liver I/R in rats, focusing on Toll-like receptor (TLR) 4 signaling, which has been shown to be involved in I/R injury. Material and methods Twenty-four male Wistar rats were randomized into four groups: Saline + Sham, Saline + I/R, Paricalcitol + Sham, and Paricalcitol + I/R. A synthetic vitamin D2 analogue, paricalcitol, was intraperitoneally injected 24 h prior to surgery. The animals were subjected to 60 min of partial warm ischemia (70%), followed by reperfusion for 6 h on the same day. The ischemic lobe of the liver and blood were collected for molecular biochemical analyses. Results Liver damage following I/R was diminished by pretreatment with paricalcitol. Pretreatment with paricalcitol decreased the levels of pro-inflammatory mediators, such as interleukin (IL)-1β, tumor necrosis factor (TNF)-α, and macrophage migration inhibitory factor (MIF), in both plasma and liver tissue. In addition, pretreatment with paricalcitol markedly down-regulated the expression of TLR4, HMGB1, TNF-α and NF-κB. Conclusions The vitamin D analogue paricalcitol attenuates hepatic I/R injury through down-regulation of the TLR4 signaling pathway and might be considered to be a potential nutritional therapeutic agent against I/R injury in the liver. PMID:28261302

  7. Med1 subunit of the mediator complex in nuclear receptor-regulated energy metabolism, liver regeneration, and hepatocarcinogenesis.

    PubMed

    Jia, Yuzhi; Viswakarma, Navin; Reddy, Janardan K

    2014-01-01

    Several nuclear receptors regulate diverse metabolic functions that impact on critical biological processes, such as development, differentiation, cellular regeneration, and neoplastic conversion. In the liver, some members of the nuclear receptor family, such as peroxisome proliferator-activated receptors (PPARs), constitutive androstane receptor (CAR), farnesoid X receptor (FXR), liver X receptor (LXR), pregnane X receptor (PXR), glucocorticoid receptor (GR), and others, regulate energy homeostasis, the formation and excretion of bile acids, and detoxification of xenobiotics. Excess energy burning resulting from increases in fatty acid oxidation systems in liver generates reactive oxygen species, and the resulting oxidative damage influences liver regeneration and liver tumor development. These nuclear receptors are important sensors of exogenous activators as well as receptor-specific endogenous ligands. In this regard, gene knockout mouse models revealed that some lipid-metabolizing enzymes generate PPARα-activating ligands, while others such as ACOX1 (fatty acyl-CoA oxidase1) inactivate these endogenous PPARα activators. In the absence of ACOX1, the unmetabolized ACOX1 substrates cause sustained activation of PPARα, and the resulting increase in energy burning leads to hepatocarcinogenesis. Ligand-activated nuclear receptors recruit the multisubunit Mediator complex for RNA polymerase II-dependent gene transcription. Evidence indicates that the Med1 subunit of the Mediator is essential for PPARα, PPARγ, CAR, and GR signaling in liver. Med1 null hepatocytes fail to respond to PPARα activators in that these cells do not show induction of peroxisome proliferation and increases in fatty acid oxidation enzymes. Med1-deficient hepatocytes show no increase in cell proliferation and do not give rise to liver tumors. Identification of nuclear receptor-specific coactivators and Mediator subunits should further our understanding of the complexities of metabolic

  8. β-Arrestin 1 and 2 differentially regulate heptahelical receptor signaling and trafficking

    PubMed Central

    Kohout, Trudy A.; Lin, Fang-Tsyr; Perry, Stephen J.; Conner, David A.; Lefkowitz, Robert J.

    2001-01-01

    The two widely coexpressed isoforms of β-arrestin (termed βarrestin 1 and 2) are highly similar in amino acid sequence. The β-arrestins bind phosphorylated heptahelical receptors to desensitize and target them to clathrin-coated pits for endocytosis. To better define differences in the roles of β-arrestin 1 and 2, we prepared mouse embryonic fibroblasts from knockout mice that lack one of the β-arrestins (βarr1-KO and βarr2-KO) or both (βarr1/2-KO), as well as their wild-type (WT) littermate controls. These cells were analyzed for their ability to support desensitization and sequestration of the β2-adrenergic receptor (β2-AR) and the angiotensin II type 1A receptor (AT1A-R). Both βarr1-KO and βarr2-KO cells showed similar impairment in agonist-stimulated β2-AR and AT1A-R desensitization, when compared with their WT control cells, and the βarr1/2-KO cells were even further impaired. Sequestration of the β2-AR in the βarr2-KO cells was compromised significantly (87% reduction), whereas in the βarr1-KO cells it was not. Agonist-stimulated internalization of the AT1A-R was only slightly reduced in the βarr1-KO but was unaffected in the βarr2-KO cells. In the βarr1/2-KO cells, the sequestration of both receptors was dramatically reduced. Comparison of the ability of the two β-arrestins to sequester the β2-AR revealed β-arrestin 2 to be 100-fold more potent than β-arrestin 1. Down-regulation of the β2-AR was also prevented in the βarr1/2-KO cells, whereas no change was observed in the single knockout cells. These findings suggest that sequestration of various heptahelical receptors is regulated differently by the two β-arrestins, whereas both isoforms are capable of supporting receptor desensitization and down-regulation. PMID:11171997

  9. Adult-Onset Hypothyroidism Enhances Fear Memory and Upregulates Mineralocorticoid and Glucocorticoid Receptors in the Amygdala

    PubMed Central

    Montero-Pedrazuela, Ana; Fernández-Lamo, Iván; Alieva, María; Pereda-Pérez, Inmaculada; Venero, César; Guadaño-Ferraz, Ana

    2011-01-01

    Hypothyroidism is the most common hormonal disease in adults, which is frequently accompanied by learning and memory impairments and emotional disorders. However, the deleterious effects of thyroid hormones deficiency on emotional memory are poorly understood and often underestimated. To evaluate the consequences of hypothyroidism on emotional learning and memory, we have performed a classical Pavlovian fear conditioning paradigm in euthyroid and adult-thyroidectomized Wistar rats. In this experimental model, learning acquisition was not impaired, fear memory was enhanced, memory extinction was delayed and spontaneous recovery of fear memory was exacerbated in hypothyroid rats. The potentiation of emotional memory under hypothyroidism was associated with an increase of corticosterone release after fear conditioning and with higher expression of glucocorticoid and mineralocorticoid receptors in the lateral and basolateral nuclei of the amygdala, nuclei that are critically involved in the circuitry of fear memory. Our results demonstrate for the first time that adult-onset hypothyroidism potentiates fear memory and also increases vulnerability to develop emotional memories. Furthermore, our findings suggest that enhanced corticosterone signaling in the amygdala is involved in the pathophysiological mechanisms of fear memory potentiation. Therefore, we recommend evaluating whether inappropriate regulation of fear in patients with post-traumatic stress and other mental disorders is associated with abnormal levels of thyroid hormones, especially those patients refractory to treatment. PMID:22039511

  10. Adult-onset hypothyroidism enhances fear memory and upregulates mineralocorticoid and glucocorticoid receptors in the amygdala.

    PubMed

    Montero-Pedrazuela, Ana; Fernández-Lamo, Iván; Alieva, María; Pereda-Pérez, Inmaculada; Venero, César; Guadaño-Ferraz, Ana

    2011-01-01

    Hypothyroidism is the most common hormonal disease in adults, which is frequently accompanied by learning and memory impairments and emotional disorders. However, the deleterious effects of thyroid hormones deficiency on emotional memory are poorly understood and often underestimated. To evaluate the consequences of hypothyroidism on emotional learning and memory, we have performed a classical Pavlovian fear conditioning paradigm in euthyroid and adult-thyroidectomized Wistar rats. In this experimental model, learning acquisition was not impaired, fear memory was enhanced, memory extinction was delayed and spontaneous recovery of fear memory was exacerbated in hypothyroid rats. The potentiation of emotional memory under hypothyroidism was associated with an increase of corticosterone release after fear conditioning and with higher expression of glucocorticoid and mineralocorticoid receptors in the lateral and basolateral nuclei of the amygdala, nuclei that are critically involved in the circuitry of fear memory. Our results demonstrate for the first time that adult-onset hypothyroidism potentiates fear memory and also increases vulnerability to develop emotional memories. Furthermore, our findings suggest that enhanced corticosterone signaling in the amygdala is involved in the pathophysiological mechanisms of fear memory potentiation. Therefore, we recommend evaluating whether inappropriate regulation of fear in patients with post-traumatic stress and other mental disorders is associated with abnormal levels of thyroid hormones, especially those patients refractory to treatment.

  11. Effects of a single glucocorticoid injection on propylene glycol-treated cows with clinical ketosis.

    PubMed

    van der Drift, Saskia G A; Houweling, Martin; Bouman, Marina; Koets, Ad P; Tielens, Aloysius G M; Nielen, Mirjam; Jorritsma, Ruurd

    2015-05-01

    This study investigated the metabolic effects of glucocorticoids when administered to propylene glycol-treated cows with clinical ketosis. Clinical ketosis was defined by depressed feed intake and milk production, and a maximal score for acetoacetate in urine. All cows received 250 mL oral propylene glycol twice daily for 3 days and were randomly assigned to a single intramuscular injection with sterile isotonic saline solution (n = 14) or dexamethasone-21-isonicotinate (n = 17). Metabolic blood variables were monitored for 6 days and adipose tissue variables for 3 days. β-Hydroxybutyrate (BHBA) concentrations in blood decreased in all cows during treatment, but were lower in glucocorticoid-treated cows. Cows treated with glucocorticoids had higher plasma glucose and insulin concentrations, whereas concentrations of non-esterified fatty acids, 3-methylhistidine and growth hormone were unaffected. mRNA expression of hormone-sensitive lipase, BHBA receptor and peroxisome proliferator-activated receptor type γ in adipose tissue was not affected. This shows that lipolytic effects do not appear to be important in ketotic cows when glucocorticoids are combined with PG. Plasma 3-methyl histidine concentrations were similar in both groups, suggesting that glucocorticoids did not increase muscle breakdown and that the greater rise in plasma glucose in glucocorticoid-treated cows may not be due to increased supply of glucogenic amino acids from muscle. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. RNA sequencing analysis of human podocytes reveals glucocorticoid regulated gene networks targeting non-immune pathways

    PubMed Central

    Jiang, Lulu; Hindmarch, Charles C. T.; Rogers, Mark; Campbell, Colin; Waterfall, Christy; Coghill, Jane; Mathieson, Peter W.; Welsh, Gavin I.

    2016-01-01

    Glucocorticoids are steroids that reduce inflammation and are used as immunosuppressive drugs for many diseases. They are also the mainstay for the treatment of minimal change nephropathy (MCN), which is characterised by an absence of inflammation. Their mechanisms of action remain elusive. Evidence suggests that immunomodulatory drugs can directly act on glomerular epithelial cells or ‘podocytes’, the cell type which is the main target of injury in MCN. To understand the nature of glucocorticoid effects on non-immune cell functions, we generated RNA sequencing data from human podocyte cell lines and identified the genes that are significantly regulated in dexamethasone-treated podocytes compared to vehicle-treated cells. The upregulated genes are of functional relevance to cytoskeleton-related processes, whereas the downregulated genes mostly encode pro-inflammatory cytokines and growth factors. We observed a tendency for dexamethasone-upregulated genes to be downregulated in MCN patients. Integrative analysis revealed gene networks composed of critical signaling pathways that are likely targeted by dexamethasone in podocytes. PMID:27774996

  13. Prevalent Glucocorticoid and Androgen Activity in US Water Sources

    PubMed Central

    Stavreva, Diana A.; George, Anuja A.; Klausmeyer, Paul; Varticovski, Lyuba; Sack, Daniel; Voss, Ty C.; Schiltz, R. Louis; Blazer, Vicki S.; Iwanowicz, Luke R.; Hager, Gordon L.

    2012-01-01

    Contamination of the environment with endocrine disrupting chemicals (EDCs) is a major health concern. The presence of estrogenic compounds in water and their deleterious effect are well documented. However, detection and monitoring of other classes of EDCs is limited. Here we utilize a high-throughput live cell assay based on sub-cellular relocalization of GFP-tagged glucocorticoid and androgen receptors (GFP-GR and GFP-AR), in combination with gene transcription analysis, to screen for glucocorticoid and androgen activity in water samples. We report previously unrecognized glucocorticoid activity in 27%, and androgen activity in 35% of tested water sources from 14 states in the US. Steroids of both classes impact body development, metabolism, and interfere with reproductive, endocrine, and immune systems. This prevalent contamination could negatively affect wildlife and human populations. PMID:23226835

  14. Prevalent glucocorticoid and androgen activity in US water sources.

    PubMed

    Stavreva, Diana A; George, Anuja A; Klausmeyer, Paul; Varticovski, Lyuba; Sack, Daniel; Voss, Ty C; Schiltz, R Louis; Blazer, Vicki S; Iwanowicz, Luke R; Hager, Gordon L

    2012-01-01

    Contamination of the environment with endocrine disrupting chemicals (EDCs) is a major health concern. The presence of estrogenic compounds in water and their deleterious effect are well documented. However, detection and monitoring of other classes of EDCs is limited. Here we utilize a high-throughput live cell assay based on sub-cellular relocalization of GFP-tagged glucocorticoid and androgen receptors (GFP-GR and GFP-AR), in combination with gene transcription analysis, to screen for glucocorticoid and androgen activity in water samples. We report previously unrecognized glucocorticoid activity in 27%, and androgen activity in 35% of tested water sources from 14 states in the US. Steroids of both classes impact body development, metabolism, and interfere with reproductive, endocrine, and immune systems. This prevalent contamination could negatively affect wildlife and human populations.

  15. Effects of a glucocorticoid receptor agonist, dexamethasone, on fathead minnow reproduction, growth, and development.

    PubMed

    LaLone, Carlie A; Villeneuve, Daniel L; Olmstead, Allen W; Medlock, Elizabeth K; Kahl, Michael D; Jensen, Kathleen M; Durhan, Elizabeth J; Makynen, Elizabeth A; Blanksma, Chad A; Cavallin, Jenna E; Thomas, Linnea M; Seidl, Sara M; Skolness, Sarah Y; Wehmas, Leah C; Johnson, Rodney D; Ankley, Gerald T

    2012-03-01

    Synthetic glucocorticoids are pharmaceutical compounds prescribed in human and veterinary medicine as anti-inflammatory agents and have the potential to contaminate natural watersheds via inputs from wastewater treatment facilities and confined animal-feeding operations. Despite this, few studies have examined the effects of this class of chemicals on aquatic vertebrates. To generate data to assess potential risk to the aquatic environment, we used fathead minnow 21-d reproduction and 29-d embryo-larvae assays to determine reproductive toxicity and early-life-stage effects of dexamethasone. Exposure to 500 µg dexamethasone/L in the 21-d test caused reductions in fathead minnow fecundity and female plasma estradiol concentrations and increased the occurrence of abnormally hatched fry. Female fish exposed to 500 µg dexamethasone/L also displayed a significant increase in plasma vitellogenin protein levels, possibly because of decreased spawning. A decrease in vitellogenin messenger ribonucleic acid (mRNA) expression in liver tissue from females exposed to the high dexamethasone concentration lends support to this hypothesis. Histological results indicate that a 29-d embryo-larval exposure to 500 µg dexamethasone/L caused a significant increase in deformed gill opercula. Fry exposed to 500 µg dexamethasone/L for 29 d also exhibited a significant reduction in weight and length compared with control fry. Taken together, these results indicate that nonlethal concentrations of a model glucocorticoid receptor agonist can impair fish reproduction, growth, and development. Copyright © 2011 SETAC.

  16. The Role and Mechanisms of Action of Glucocorticoid Involvement in Memory Storage

    PubMed Central

    Sandi, Carmen

    1998-01-01

    Adrenal steroid hormones modulate learning and memory processes by interacting with specific glucocorticoid receptors at different brain areas. In this article, certain components of the physiological response to stress elicited by learning situations are proposed to form an integral aspect of the neurobiological mechanism underlying memory formation. By reviewing the work carried out in different learning models in chicks (passive avoidance learning) and rats (spatial orientation in the Morris water maze and contextual fear conditioning), a role for brain corticosterone action through the glucocorticoid receptor type on the mechanisms of memory consolidation is hypothesized. Evidence is also presented to relate post-training corticosterone levels to the strength of memory storage. Finally, the possible molecular mechanisms that might mediate the influences of glucocorticoids in synaptic plasticity subserving long-term memory formation are considered, mainly by focusing on studies implicating a steroid action through (i) glutamatergic transmission and (ii) cell adhesion molecules. PMID:9920681

  17. Metabotropic glutamate receptor-mediated use-dependent down-regulation of synaptic excitability involves the fragile X mental retardation protein.

    PubMed

    Repicky, Sarah; Broadie, Kendal

    2009-02-01

    Loss of the mRNA-binding protein FMRP results in the most common inherited form of both mental retardation and autism spectrum disorders: fragile X syndrome (FXS). The leading FXS hypothesis proposes that metabotropic glutamate receptor (mGluR) signaling at the synapse controls FMRP function in the regulation of local protein translation to modulate synaptic transmission strength. In this study, we use the Drosophila FXS disease model to test the relationship between Drosophila FMRP (dFMRP) and the sole Drosophila mGluR (dmGluRA) in regulation of synaptic function, using two-electrode voltage-clamp recording at the glutamatergic neuromuscular junction (NMJ). Null dmGluRA mutants show minimal changes in basal synapse properties but pronounced defects during sustained high-frequency stimulation (HFS). The double null dfmr1;dmGluRA mutant shows repression of enhanced augmentation and delayed onset of premature long-term facilitation (LTF) and strongly reduces grossly elevated post-tetanic potentiation (PTP) phenotypes present in dmGluRA-null animals. Null dfmr1 mutants show features of synaptic hyperexcitability, including multiple transmission events in response to a single stimulus and cyclic modulation of transmission amplitude during prolonged HFS. The double null dfmr1;dmGluRA mutant shows amelioration of these defects but does not fully restore wildtype properties in dfmr1-null animals. These data suggest that dmGluRA functions in a negative feedback loop in which excess glutamate released during high-frequency transmission binds the glutamate receptor to dampen synaptic excitability, and dFMRP functions to suppress the translation of proteins regulating this synaptic excitability. Removal of the translational regulator partially compensates for loss of the receptor and, similarly, loss of the receptor weakly compensates for loss of the translational regulator.

  18. Lifetime stress accelerates epigenetic aging in an urban, African American cohort: relevance of glucocorticoid signaling.

    PubMed

    Zannas, Anthony S; Arloth, Janine; Carrillo-Roa, Tania; Iurato, Stella; Röh, Simone; Ressler, Kerry J; Nemeroff, Charles B; Smith, Alicia K; Bradley, Bekh; Heim, Christine; Menke, Andreas; Lange, Jennifer F; Brückl, Tanja; Ising, Marcus; Wray, Naomi R; Erhardt, Angelika; Binder, Elisabeth B; Mehta, Divya

    2015-12-17

    Chronic psychological stress is associated with accelerated aging and increased risk for aging-related diseases, but the underlying molecular mechanisms are unclear. We examined the effect of lifetime stressors on a DNA methylation-based age predictor, epigenetic clock. After controlling for blood cell-type composition and lifestyle parameters, cumulative lifetime stress, but not childhood maltreatment or current stress alone, predicted accelerated epigenetic aging in an urban, African American cohort (n = 392). This effect was primarily driven by personal life stressors, was more pronounced with advancing age, and was blunted in individuals with higher childhood abuse exposure. Hypothesizing that these epigenetic effects could be mediated by glucocorticoid signaling, we found that a high number (n = 85) of epigenetic clock CpG sites were located within glucocorticoid response elements. We further examined the functional effects of glucocorticoids on epigenetic clock CpGs in an independent sample with genome-wide DNA methylation (n = 124) and gene expression data (n = 297) before and after exposure to the glucocorticoid receptor agonist dexamethasone. Dexamethasone induced dynamic changes in methylation in 31.2 % (110/353) of these CpGs and transcription in 81.7 % (139/170) of genes neighboring epigenetic clock CpGs. Disease enrichment analysis of these dexamethasone-regulated genes showed enriched association for aging-related diseases, including coronary artery disease, arteriosclerosis, and leukemias. Cumulative lifetime stress may accelerate epigenetic aging, an effect that could be driven by glucocorticoid-induced epigenetic changes. These findings contribute to our understanding of mechanisms linking chronic stress with accelerated aging and heightened disease risk.

  19. Impaired glucocorticoid-mediated HPA axis negative feedback induced by juvenile social isolation in male rats.

    PubMed

    Boero, Giorgia; Pisu, Maria Giuseppina; Biggio, Francesca; Muredda, Laura; Carta, Gianfranca; Banni, Sebastiano; Paci, Elena; Follesa, Paolo; Concas, Alessandra; Porcu, Patrizia; Serra, Mariangela

    2018-05-01

    We previously demonstrated that socially isolated rats at weaning showed a significant decrease in corticosterone and adrenocorticotropic hormone (ACTH) levels, associated with an enhanced response to acute stressful stimuli. Here we shown that social isolation decreased levels of total corticosterone and of its carrier corticosteroid-binding globulin, but did not influence the availability of the free active fraction of corticosterone, both under basal conditions and after acute stress exposure. Under basal conditions, social isolation increased the abundance of glucocorticoid receptors, while it decreased that of mineralocorticoid receptors. After acute stress exposure, socially isolated rats showed long-lasting corticosterone, ACTH and corticotrophin releasing hormone responses. Moreover, while in the hippocampus and hypothalamus of group-housed rats glucocorticoid receptors expression increased with time and reached a peak when corticosterone levels returned to basal values, in socially isolated rats expression of glucocorticoid receptors did not change. Finally, social isolation also affected the hypothalamic endocannabinoid system: compared to group-housed rats, basal levels of anandamide and cannabinoid receptor type 1 were increased, while basal levels of 2-arachidonoylglycerol were decreased in socially isolated rats and did not change after acute stress exposure. The present results show that social isolation in male rats alters basal HPA axis activity and impairs glucocorticoid-mediated negative feedback after acute stress. Given that social isolation is considered an animal model of several neuropsychiatric disorders, such as generalized anxiety disorder, depression, post-traumatic stress disorder and schizophrenia, these data could contribute to better understand the alterations in HPA axis activity observed in these disorders. Copyright © 2018 Elsevier Ltd. All rights reserved.

  20. Hypothalamic-Pituitary-Adrenal Axis Modulation of Glucocorticoids in the Cardiovascular System.

    PubMed

    Burford, Natalie G; Webster, Natalia A; Cruz-Topete, Diana

    2017-10-16

    The collective of endocrine organs acting in homeostatic regulation-known as the hypothalamic-pituitary-adrenal (HPA) axis-comprises an integration of the central nervous system as well as peripheral tissues. These organs respond to imminent or perceived threats that elicit a stress response, primarily culminating in the release of glucocorticoids into the systemic circulation by the adrenal glands. Although the secretion of glucocorticoids serves to protect and maintain homeostasis in the typical operation at baseline levels, inadequate regulation can lead to physiologic and psychologic pathologies. The cardiovascular system is especially susceptible to prolonged dysregulation of the HPA axis and glucocorticoid production. There is debate about whether cardiovascular health risks arise from the direct detrimental effects of stress axis activation or whether pathologies develop secondary to the accompanying metabolic strain of excess glucocorticoids. In this review, we will explore the emerging research that indicates stress does have direct effects on the cardiovascular system via the HPA axis activation, with emphasis on the latest research on the impact of glucocorticoids signaling in the vasculature and the heart.

  1. Neurobiological mechanisms underlying relapse to cocaine use: contributions of CRF and noradrenergic systems and regulation by glucocorticoids.

    PubMed

    McReynolds, Jayme R; Peña, David F; Blacktop, Jordan M; Mantsch, John R

    2014-01-01

    Considering its pervasive and uncontrollable influence in drug addicts, understanding the neurobiological processes through which stress contributes to drug use is a critical goal for addiction researchers and will likely be important for the development of effective medications aimed at relapse prevention. In this paper, we review work from our laboratory and others focused on determining the neurobiological mechanisms that underlie and contribute to stress-induced relapse of cocaine use with an emphasis on the actions of corticotropin-releasing factor in the ventral tegmental area (VTA) and a key pathway from the bed nucleus of the stria terminalis to the VTA that is regulated by norepinephrine and beta adrenergic receptors. Additionally, we discuss work suggesting that the influence of stress in cocaine addiction changes and intensifies with repeated cocaine use in an intake-dependent manner and examine the potential role of glucocorticoid hormones in the underlying drug-induced neuroadaptations. It is our hope that research in this area will inform clinical practice and medication development aimed at minimizing the contribution of stress to the addiction cycle, thereby improving treatment outcomes and reducing the societal costs of addiction.

  2. Toll-like Receptor 3 (TLR3) Induces Apoptosis via Death Receptors and Mitochondria by Up-regulating the Transactivating p63 Isoform α (TAP63α)*

    PubMed Central

    Sun, Ruili; Zhang, Yu; Lv, Qingshan; Liu, Bei; Jin, Miao; Zhang, Weijia; He, Qing; Deng, Minjie; Liu, Xueting; Li, Guancheng; Li, Yuehui; Zhou, Guohua; Xie, Pingli; Xie, Xiumei; Hu, Jinyue; Duan, Zhaojun

    2011-01-01

    Toll-like receptor 3 (TLR3), a member of the pathogen recognition receptors, is widely expressed in various cells and has been shown to activate immune signaling pathways by recognizing viral double-stranded RNA. Recently, it was reported that the activation of TLR3 induced apoptosis in some cells, but the detailed molecular mechanism is not fully understood. In this study, we found that in endothelial cells polyinosinic-polycytidylic acid (poly(I-C)) induced dose- and time-dependent cell apoptosis, which was elicited by TLR3 activation, as TLR3 neutralization and down-regulation repressed the apoptosis. Poly(I-C) induced the activation of both caspases 8 and 9, indicating that TLR3 triggered the signaling of both the extrinsic and intrinsic apoptotic pathways. Poly(I-C) up-regulated tumor necrosis factor-related apoptosis-inducing ligand and its receptors, death receptors 4/5, resulting in initiating the extrinsic pathway. Furthermore, poly(I-C) down-regulated anti-apoptotic protein, B cell lymphoma 2 (Bcl-2), and up-regulated Noxa, a key Bcl-2 homology 3-only antagonist of Bcl-2, leading to the priming of the intrinsic pathway. A p53-related protein, the transactivating p63 isoform α (TAp63α), was induced by TLR3 activation and contributed to the activation of both the intrinsic and extrinsic apoptotic pathways. Both the cells deficient in p63 gene expression by RNA interference and cells that overexpressed the N-terminally truncated p63 isoform α (ΔNp63α), a dominant-negative variant of TAp63α, by gene transfection, survived TLR3 activation. Taken together, TAp63α is a crucial regulator downstream of TLR3 to induce cell death via death receptors and mitochondria. PMID:21367858

  3. The Immunoexpression of Glucocorticoid Receptors in Breast Carcinomas, Lactational Change, and Normal Breast Epithelium and Its Possible Role in Mammary Carcinogenesis

    PubMed Central

    Wazir, Javed Fayyaz; Brahmi, Urmil Prabha; Fakhro, Abdul Rahman

    2017-01-01

    The role of estrogen and progesterone receptors in breast cancer biology is well established. In contrast, other steroid hormones are less well studied. Glucocorticoids (GCs) are known to play a role in mammary development and differentiation; thus, it is of interest to attempt to delineate their immunoexpression across a spectrum of mammary epithelia. Aim. To delineate the distribution pattern of glucocorticoid receptors (GRs) in malignant versus nonmalignant epithelium with particular emphasis on lactational epithelium. Materials and Methods. Immunohistochemistry (IHC) for GRs was performed on archival formalin-fixed paraffin-embedded tissue blocks of 96 cases comprising 52 invasive carcinomas, 21 cases with lactational change, and 23 cases showing normal mammary tissue histology. Results. Results reveal an overexpression of GRs in mammary malignant epithelium as compared to both normal and lactational groups individually and combined. GR overexpression is significantly more pronounced in HER-2-negative cancers. Discussion. This is the first study to compare GR expression in human lactating epithelium versus malignant and normal epithelium. The article discusses the literature related to the pathobiology of GCs in the breast with special emphasis on breast cancer. Conclusion. The lactational epithelium did not show overexpression of GR, while GR was overexpressed in mammary NST (ductal) carcinoma, particularly HER-2-negative cancers. PMID:29348941

  4. Stress Increases Peripheral Axon Growth and Regeneration through Glucocorticoid Receptor-Dependent Transcriptional Programs

    PubMed Central

    Alexander, Jessica K.; Madalena, Kathryn M.; Motti, Dario; Quach, Tam; Zha, Alicia; Webster Marketon, Jeanette

    2017-01-01

    Abstract Stress and glucocorticoid (GC) release are common behavioral and hormonal responses to injury or disease. In the brain, stress/GCs can alter neuron structure and function leading to cognitive impairment. Stress and GCs also exacerbate pain, but whether a corresponding change occurs in structural plasticity of sensory neurons is unknown. Here, we show that in female mice (Mus musculus) basal GC receptor (Nr3c1, also known as GR) expression in dorsal root ganglion (DRG) sensory neurons is 15-fold higher than in neurons in canonical stress-responsive brain regions (M. musculus). In response to stress or GCs, adult DRG neurite growth increases through mechanisms involving GR-dependent gene transcription. In vivo, prior exposure to an acute systemic stress increases peripheral nerve regeneration. These data have broad clinical implications and highlight the importance of stress and GCs as novel behavioral and circulating modifiers of neuronal plasticity. PMID:28828403

  5. 11β-Hydroxysteroid Dehydrogenases: Intracellular Gate-Keepers of Tissue Glucocorticoid Action

    PubMed Central

    Chapman, Karen; Holmes, Megan

    2013-01-01

    Glucocorticoid action on target tissues is determined by the density of “nuclear” receptors and intracellular metabolism by the two isozymes of 11β-hydroxysteroid dehydrogenase (11β-HSD) which catalyze interconversion of active cortisol and corticosterone with inert cortisone and 11-dehydrocorticosterone. 11β-HSD type 1, a predominant reductase in most intact cells, catalyzes the regeneration of active glucocorticoids, thus amplifying cellular action. 11β-HSD1 is widely expressed in liver, adipose tissue, muscle, pancreatic islets, adult brain, inflammatory cells, and gonads. 11β-HSD1 is selectively elevated in adipose tissue in obesity where it contributes to metabolic complications. Similarly, 11β-HSD1 is elevated in the ageing brain where it exacerbates glucocorticoid-associated cognitive decline. Deficiency or selective inhibition of 11β-HSD1 improves multiple metabolic syndrome parameters in rodent models and human clinical trials and similarly improves cognitive function with ageing. The efficacy of inhibitors in human therapy remains unclear. 11β-HSD2 is a high-affinity dehydrogenase that inactivates glucocorticoids. In the distal nephron, 11β-HSD2 ensures that only aldosterone is an agonist at mineralocorticoid receptors (MR). 11β-HSD2 inhibition or genetic deficiency causes apparent mineralocorticoid excess and hypertension due to inappropriate glucocorticoid activation of renal MR. The placenta and fetus also highly express 11β-HSD2 which, by inactivating glucocorticoids, prevents premature maturation of fetal tissues and consequent developmental “programming.” The role of 11β-HSD2 as a marker of programming is being explored. The 11β-HSDs thus illuminate the emerging biology of intracrine control, afford important insights into human pathogenesis, and offer new tissue-restricted therapeutic avenues. PMID:23899562

  6. Analysis of the hormone-binding domain of steroid receptors using chimeras generated by homologous recombination

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Martinez, Elisabeth D.; Pattabiraman, Nagarajan; Department of Oncology, Georgetown University School of Medicine, Washington, DC 20057

    2005-08-15

    The glucocorticoid receptor and the mineralocorticoid receptor are members of the steroid receptor family that exhibit ligand cross-reactivity. Specificity of steroid receptor action is investigated in the present work by the construction and characterization of chimeras between the glucocorticoid receptor and the mineralocorticoid receptor. We used an innovative approach to make novel steroid receptor proteins in vivo that in general, contrary to our expectations, show increased ligand specificity compared to the parental receptors. We describe a receptor that is specific for the potent synthetic glucocorticoid triamcinolone acetonide and does not bind aldosterone. A further set of chimeras has an increasedmore » ability to discriminate between ligands, responding potently to mineralocorticoids and only very weakly to synthetic glucocorticoids. A chimera with the fusion site in the hinge highlights the importance of the region between the DNA-binding and the hormone-binding domains since, unlike both the glucocorticoid and mineralocorticoid receptors, it only responds to mineralocorticoids. One chimera has reduced specificity in that it acts as a general corticoid receptor, responding to glucocorticoids and mineralocorticoids with similar potency and efficacy. Our data suggest that regions of the glucocorticoid and mineralocorticoid receptor hormone-binding domains are functionally non-reciprocal. We present transcriptional, hormone-binding, and structure-modeling evidence that suggests that receptor-specific interactions within and across domains mediate aspects of specificity in transcriptional responses to steroids.« less

  7. Endogenous glucocorticoids exacerbate cholestasis-associated liver injury and hypercholesterolemia in mice

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Geest, Rick van der, E-mail: r.van.der.geest@lacdr

    Cholestatic liver disease is characterized by a disruption of bile flow, bile acid toxicity, liver injury, and hypercholesterolemia. Relatively high secretion of glucocorticoids by the adrenals has been observed under cholestatic conditions. Here we investigated a contribution of the rise in endogenous glucocorticoids to initial stage cholestasis pathology. Adrenalectomized or sham-operated control C57BL/6 mice were given an oral dose of alpha-naphthylisothiocyanate to induce cholestasis. Adrenalectomy effectively lowered plasma corticosterone levels (18 ± 5 ng/ml vs 472 ± 58 ng/ml; P < 0.001) and disrupted the metabolic and anti-inflammatory glucocorticoid function. Adrenal removal did not exacerbate the cholestasis extent. In contrast,more » the cholestasis-associated liver injury was markedly lower in adrenalectomized mice as compared to controls as evidenced by a 84%–93% decrease in liver necrosis and plasma alanine aminotransferase and bile acid levels (P < 0.001 for all). Gene expression analysis on livers from adrenalectomized mice suggested the absence of bile acid toxicity-associated farnesoid X receptor signaling in the context of a 44% (P < 0.01) and 82% (P < 0.001) reduction in sodium/bile acid cotransporter member 1 transcript level as compared to respectively control and non-diseased mice. Adrenalectomy reduced the expression of the cholesterol synthesis gene HMG-CoA reductase by 70% (P < 0.05), which translated into a 73% lower plasma total cholesterol level (P < 0.05). Treatment of C57BL/6 mice with the glucocorticoid receptor antagonist RU-486 recapitulated the protective effect of adrenalectomy on indices of liver injury and hypercholesterolemia. In conclusion, we have shown that endogenous glucocorticoids exacerbate the liver injury and hypercholesterolemia associated with acute cholestasis in mice. - Highlights: • Cholestasis is associated with increased plasma glucocorticoid levels in mice. • Adrenalectomy lowers cholestasis

  8. Impact of chronic unpredicted mild stress-induced depression on repaglinide fate via glucocorticoid signaling pathway.

    PubMed

    Wei, Hongyan; Zhou, Ting; Tan, Boyu; Zhang, Lei; Li, Mingming; Xiao, Zhijun; Xu, Feng

    2017-07-04

    Chronic unpredicted mild stress (CUMS)-induced depression could alter the pharmacokinetics of many drugs in rats, however, the underlying mechanism is not clear. In this work we studied the pharmacokinetics of repaglinide, and explored the role of glucocorticoid and adrenergic signaling pathway in regulating drug metabolizing enzymes (DMEs) in GK rats and BRL 3A cells. The plasma cortisol and epinephrine levels were increased, meanwhile the pharmacokinetics of repaglinide were altered significantly in depression model rats. Forty-nine genes in liver of model rats displayed significant difference comparing to control rats. The differentially expressed genes enriched in the drug metabolism and steroid hormone biosynthesis pathway significantly, and Nr1i3 matched 335 connectivity genes. CAR and Ugt1a1 protein expression were enhanced significantly in liver of model rats. The mRNA expression of Ugt1a1 and Nr1i2 were increased 2 and 4 times respectively with dexamethasone (DEX) and 8-Br-cAMP co-treatment in BRL 3A cells. The protein expression of PXR was up-regulated, too. However, RU486 reversed the up-regulated effect. The adrenergic receptor agonists had little impact on the DMEs in BRL 3A. Our data suggested that CUMS-induced depression might up-regulate DMEs expression via glucocorticoid signaling pathway, and accelerate the fate of the repaglinide in spontaneous diabetes rats.

  9. Impact of chronic unpredicted mild stress-induced depression on repaglinide fate via glucocorticoid signaling pathway

    PubMed Central

    Tan, Boyu; Zhang, Lei; Li, Mingming; Xiao, Zhijun; Xu, Feng

    2017-01-01

    Chronic unpredicted mild stress (CUMS)-induced depression could alter the pharmacokinetics of many drugs in rats, however, the underlying mechanism is not clear. In this work we studied the pharmacokinetics of repaglinide, and explored the role of glucocorticoid and adrenergic signaling pathway in regulating drug metabolizing enzymes (DMEs) in GK rats and BRL 3A cells. The plasma cortisol and epinephrine levels were increased, meanwhile the pharmacokinetics of repaglinide were altered significantly in depression model rats. Forty-nine genes in liver of model rats displayed significant difference comparing to control rats. The differentially expressed genes enriched in the drug metabolism and steroid hormone biosynthesis pathway significantly, and Nr1i3 matched 335 connectivity genes. CAR and Ugt1a1 protein expression were enhanced significantly in liver of model rats. The mRNA expression of Ugt1a1 and Nr1i2 were increased 2 and 4 times respectively with dexamethasone (DEX) and 8-Br-cAMP co-treatment in BRL 3A cells. The protein expression of PXR was up-regulated, too. However, RU486 reversed the up-regulated effect. The adrenergic receptor agonists had little impact on the DMEs in BRL 3A. Our data suggested that CUMS-induced depression might up-regulate DMEs expression via glucocorticoid signaling pathway, and accelerate the fate of the repaglinide in spontaneous diabetes rats. PMID:28574832

  10. Absence of ligand-induced regulation of kinin receptor expression in the rabbit

    PubMed Central

    Sabourin, Thierry; Guay, Katline; Houle, Steeve; Bouthillier, Johanne; Bachvarov, Dimcho R; Adam, Albert; Marceau, François

    2001-01-01

    The induction of B1 receptors (B1Rs) and desensitization or down-regulation of B2 receptors (B2Rs) as a consequence of the production of endogenous kinins has been termed the autoregulation hypothesis. The latter was investigated using two models based on the rabbit: kinin stimulation of cultured vascular smooth muscle cells (SMCs) and in vivo contact system activation (dextran sulphate intravenous injection, 2 mg kg−1, 5 h).Rabbit aortic SMCs express a baseline population of B1Rs that was up-regulated upon interleukin-1β treatment ([3H]-Lys-des-Arg9-BK binding or mRNA concentration evaluated by RT–PCR; 4 or 3 h, respectively). Treatment with B1R or B2R agonists failed to alter B1R expression under the same conditions.Despite consuming endogenous kininogen (assessed using the kinetics of immunoreactive kinin formation in the plasma exposed to glass beads ex vivo) and producing hypotension mediated by B2Rs in anaesthetized rabbits, dextran sulphate treatment failed to induce B1Rs in conscious animals (RT–PCR in several organs, aortic contractility). By contrast, lipopolysaccharide (LPS, 50 μg kg−1, 5 h) was an effective B1R inducer (kidney, duodenum, aorta) but did not reduce kininogen reserve.We tested the alternate hypothesis that endogenous kinin participate in LPS induction of B1Rs. Kinin receptor antagonists (icatibant combined to B-9858, 50 μg kg−1 of each) failed to prevent or reduce the effect of LPS on B1R expression. Dextran sulphate or LPS treatments did not persistently down-regulate vascular B2Rs (jugular vein contractility assessed ex vivo).The kinin receptor autoregulation hypothesis is not applicable to primary cell cultures derived from a tissue known to express B1Rs in a regulated manner (aorta). The activation of the endogenous kallikrein-kinin system is ineffective to induce B1Rs in vivo in an experimental time frame sufficient for B1R induction by LPS. PMID:11487527

  11. Losartan protects liver against ischaemia/reperfusion injury through PPAR-γ activation and receptor for advanced glycation end-products down-regulation

    PubMed Central

    Koh, Eun-Ji; Yoon, Seong-Jin; Lee, Sun-Mee

    2013-01-01

    Background and Purpose PPAR-γ has been reported to be a protective regulator in ischaemia/reperfusion (I/R) injury. The receptor for advanced glycation end-products (RAGE) plays a major role in the innate immune response, and its expression is associated with PPAR-γ activation. Several angiotensin receptor blockers possess partial agonist activities towards PPAR-γ. Therefore, this study investigated the action of losartan, particularly with regard to PPAR-γ activation and RAGE signalling pathways during hepatic I/R. Experimental Approach Mice were subjected to 60 min of ischaemia followed by 6 h of reperfusion. Losartan (0.1, 1, 3 and 10 mg·kg−1) was administered 1 h prior to ischaemia and immediately before reperfusion. GW9662, a PPAR-γ antagonist, was administered 30 min prior to first pretreatment with losartan. Key Results Losartan enhanced the DNA-binding activity of PPAR-γ in I/R. Losartan attenuated the increased serum alanine aminotransferase activity, TNF-α and IL-6 levels, and nuclear concentrations of NF-κB in I/R. GW9662 reversed these beneficial effects. Losartan caused a decrease in apoptosis as assessed by TUNEL assay, in release of cytochrome c and in cleavage of caspase-3, and these effects were abolished by GW9662 administration. Losartan attenuated not only I/R-induced RAGE overexpression, but also its downstream early growth response protein-1-dependent macrophage inflammatory protein 2 level; phosphorylation of p38, ERK and JNK; and subsequent c-Jun phosphorylation. GW9662 reversed these effects of losartan administration. Conclusions and Implications Our findings suggest that losartan ameliorates I/R-induced liver damage through PPAR-γ activation and down-regulation of the RAGE signalling pathway. PMID:23647130

  12. Pathophysiology of Glucocorticoid Signaling.

    PubMed

    Vitellius, Géraldine; Trabado, Séverine; Bouligand, Jérôme; Delemer, Brigitte; Lombès, Marc

    2018-06-01

    Glucocorticoids (GC), such as cortisol or dexamethasone, control various physiological functions, notably those involved in development, metabolism, inflammatory processes and stress, and exert most of their effects upon binding to the glucocorticoid receptor (GR, encoded by NR3C1 gene). GC signaling follows several consecutive steps leading to target gene transactivation, including ligand binding, nuclear translocation of ligand-activated GR complexes, DNA binding, coactivator interaction and recruitment of functional transcriptional machinery. Any step may be impaired and may account for altered GC signaling. Partial or generalized glucocorticoid resistance syndrome may result in a reduced level of functional GR, a decreased hormone affinity and binding, a defect in nuclear GR translocation, a decrease or lack of DNA binding and/or post-transcriptional GR modifications. To date, 26 loss-of-function NR3C1 mutations have been reported in the context of hypertension, hirsutism, adrenal hyperplasia or metabolic disorders. These clinical signs are generally associated with biological features including hypercortisolism without negative regulatory feedback loop on the hypothalamic-pituitary-adrenal axis. Patients had often low plasma aldosterone and renin levels despite hypertension. Only one GR gain-of-function mutation has been described associating Cushing's syndrome phenotype with normal urinary-free cortisol. Some GR polymorphisms (ER22/23EK, GR-9β) have been linked to glucocorticoid resistance and a healthier metabolic profile whereas some others seemed to be associated with GC hypersensitivity (N363S, BclI), increasing cardiovascular risk (diabetes type 2, visceral obesity). This review focuses on the earlier findings on the pathophysiology of GR signaling and presents criteria facilitating identification of novel NR3C1 mutations in selected patients. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

  13. Enhanced down regulation of cortical +-propranolol sensitive ( sup 3 H)-DHA binding sites by co-administration of DMI and 5-HT sub 1A partial agonist gepirone

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Geissler, M.A.; Yocca, F.D.

    1990-02-26

    The putative interrelationship between the noradrenergic and serotonergic systems has been supported by numerous studies. Recently, Dudley et al. (1989) demonstrated significant down regulation of cortical {beta}-adrenergic receptors by co-administration of desipramine (DMI), a norepinephrine uptake inhibitor, and the full 5-HT{sub 1A} agonist 8-OH-DPAT. To this end, the effects of acute and chronic (4 and 14 day) administration of DMI, gepirone, a selective 5-HT{sub 1A} post-synaptic partial agonist, as well as a combination of the two, on cortical ({plus minus})-propranolol sensitive ({sup 3}H)-DHA binding sites were examined in rats. Down regulation was apparent after 4 and 14 day treatment withmore » DMI. However, this was not the case with gepirone. Of particular importance is the demonstration of a greater magnitude of down regulation with co-administration of a greater magnitude of down regulation with co-administration of DMI and gepirone. These results suggests that alteration in rat cortical ({plus minus})-propranolol sensitive ({sup 3}H)-DHA binding sites by noradrenergic uptake inhibitors can be further modulated by selective partial agonist activity at central 5-HT{sub 1A} postsynaptic receptors. Further data on the co-administration of DMI and BMY 7378 (7,9-dioxo-8-(2-(4-{und o}-methoxyphenylpiperazinyl)ethyl)-8-azaspiro(4,5)decane dihydrochloride), a weak partial agonist at postsynaptic 5-HT{sub 1A} receptors, are also presented.« less

  14. DHA down-regulates phenobarbital-induced cytochrome P450 2B1 gene expression in rat primary hepatocytes by attenuating CAR translocation

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Li, C.-C.; Lii, C.-K.; Liu, K.-L.

    The constitutive androstane receptor (CAR) plays an important role in regulating the expression of detoxifying enzymes, including cytochrome P450 2B (CYP 2B). Phenobarbital (PB) induction of human CYP 2B6 and mouse CYP 2b10 has been shown to be mediated by CAR. Our previous study showed that PB-induced CYP 2B1 expression in rat primary hepatocytes is down-regulated by both n-6 and n-3 polyunsaturated fatty acids (PUFAs), especially docosahexaenoic acid (DHA); however, the mechanism for this down-regulation by DHA was previously unknown. The objective of the present study was to determine whether change in CAR translocation is involved in the down-regulation bymore » n-6 and n-3 PUFAs of PB-induced CYP 2B1 expression in rat primary hepatocytes. We used 100 {mu}M arachidonic acid, linoleic acid, eicosapentaenoic acid, and DHA to test this hypothesis. PB triggered the translocation of CAR from the cytosol into the nucleus in a dose-dependent and time-dependent manner in our hepatocyte system, and the CAR distribution in rat primary hepatocytes was significantly affected by DHA. DHA treatment decreased PB-inducible accumulation of CAR in the nuclear fraction and increased it in the cytosolic fraction in a dose-dependent manner. The down-regulation of CYP 2B1 expression by DHA occurred in a dose-dependent manner, and a similar pattern was found for the nuclear accumulation of CAR. The results of immunoprecipitation showed a CAR/RXR heterodimer bound to nuclear receptor binding site 1 (NR-1) of the PB-responsive enhancer module (PBREM) of the CYP 2B1gene. The EMSA results showed that PB-induced CAR binding to NR-1 was attenuated by DHA. Taken together, these results suggest that attenuation of CAR translocation and decreased subsequent binding to NR-1 are involved in DHA's down-regulation of PB-induced CYP 2B1 expression.« less

  15. Long-term dysregulation of brain corticotrophin and glucocorticoid receptors and stress reactivity by single early-life pain experience in male and female rats.

    PubMed

    Victoria, Nicole C; Inoue, Kiyoshi; Young, Larry J; Murphy, Anne Z

    2013-12-01

    Inflammatory pain experienced on the day of birth (postnatal day 0: PD0) significantly dampens behavioral responses to stress- and anxiety-provoking stimuli in adult rats. However, to date, the mechanisms by which early life pain permanently alters adult stress responses remain unknown. The present studies examined the impact of inflammatory pain, experienced on the day of birth, on adult expression of receptors or proteins implicated in the activation and termination of the stress response, including corticotrophin releasing factor receptors (CRFR1 and CRFR2) and glucocorticoid receptor (GR). Using competitive receptor autoradiography, we show that Sprague Dawley male and female rat pups administered 1% carrageenan into the intraplantar surface of the hindpaw on the day of birth have significantly decreased CRFR1 binding in the basolateral amygdala and midbrain periaqueductal gray in adulthood. In contrast, CRFR2 binding, which is associated with stress termination, was significantly increased in the lateral septum and cortical amygdala. GR expression, measured with in situ hybridization and immunohistochemistry, was significantly increased in the paraventricular nucleus of the hypothalamus and significantly decreased in the hippocampus of neonatally injured adults. In parallel, acute stress-induced corticosterone release was significantly attenuated and returned to baseline more rapidly in adults injured on PD0 in comparison to controls. Collectively, these data show that early life pain alters neural circuits that regulate responses to and neuroendocrine recovery from stress, and suggest that pain experienced by infants in the Neonatal Intensive Care Unit may permanently alter future responses to anxiety- and stress-provoking stimuli. Published by Elsevier Ltd.

  16. The ubiquitin ligase Mdm2 controls oligodendrocyte maturation by intertwining mTOR with G protein-coupled receptor kinase 2 in the regulation of GPR17 receptor desensitization.

    PubMed

    Fumagalli, Marta; Bonfanti, Elisabetta; Daniele, Simona; Zappelli, Elisa; Lecca, Davide; Martini, Claudia; Trincavelli, Maria L; Abbracchio, Maria P

    2015-12-01

    During oligodendrocyte precursor cell (OPC) differentiation, defective control of the membrane receptor GPR17 has been suggested to block cell maturation and impair remyelination under demyelinating conditions. After the immature oligodendrocyte stage, to enable cells to complete maturation, GPR17 is physiologically down-regulated via phosphorylation/desensitization by G protein-coupled receptor kinases (GRKs); conversely, GRKs are regulated by the "mammalian target of rapamycin" mTOR. However, how GRKs and mTOR are connected to each other in modulating GPR17 function and oligodendrogenesis has remained elusive. Here we show, for the first time, a role for Murine double minute 2 (Mdm2), a ligase previously involved in ubiquitination/degradation of the onco-suppressor p53 protein. In maturing OPCs, both rapamycin and Nutlin-3, a small molecule inhibitor of Mdm2-p53 interactions, increased GRK2 sequestration by Mdm2, leading to impaired GPR17 down-regulation and OPC maturation block. Thus, Mdm2 intertwines mTOR with GRK2 in regulating GPR17 and oligodendrogenesis and represents a novel actor in myelination. © 2015 Wiley Periodicals, Inc.

  17. SGK is a primary glucocorticoid-induced gene in the human.

    PubMed

    Náray-Fejes-Tóth, A; Fejes-Tóth, G; Volk, K A; Stokes, J B

    2000-12-01

    Serum- and glucocorticoid-induced kinase (sgk) is transcriptionally regulated by corticosteroids in several cell types. Recent findings suggest that sgk is an important gene in the early action of corticosteroids on epithelial sodium reabsorption. Surprisingly, the human sgk was reported not to be transcriptionally regulated by corticosteroids in a hepatoma cell line, and thus far no glucocorticoid response element has been identified in the human SGK gene. Since humans clearly respond to both aldosterone and glucocorticoids in cells where sgk action seems to be important, in this study we determined sgk mRNA levels following dexamethasone treatment for various duration in five human cell lines. These cell lines included epithelial cells (H441, T84 and HT29) and lymphoid/monocyte (U937 and THP-1) lines. Using quantitative reverse transcriptase-polymerase chain reaction (RT-PCR), we found that sgk mRNA levels are markedly induced by glucocorticoids in all of the five cell lines studied. Time course analyses revealed that sgk mRNA levels are elevated as early as 30 min after addition of the glucocorticoid, and remain elevated for several hours. Northern analysis in H441 cells confirmed that sgk is an early induced gene. The induction of sgk by dexamethasone was unaffected by cycloheximide, indicating that it does not require de novo protein synthesis. These results indicate that the human sgk, just like its counterparts in other species, is a primary glucocorticoid-induced gene.

  18. Role of hippocampal β-adrenergic and glucocorticoid receptors in the novelty-induced enhancement of fear extinction.

    PubMed

    Liu, Jian-Feng; Yang, Chang; Deng, Jia-Hui; Yan, Wei; Wang, Hui-Min; Luo, Yi-Xiao; Shi, Hai-Shui; Meng, Shi-Qiu; Chai, Bai-Sheng; Fang, Qin; Chai, Ning; Xue, Yan-Xue; Sun, Jia; Chen, Chen; Wang, Xue-Yi; Wang, Ji-Shi; Lu, Lin

    2015-05-27

    Fear extinction forms a new memory but does not erase the original fear memory. Exposure to novelty facilitates transfer of short-term extinction memory to long-lasting memory. However, the underlying cellular and molecular mechanisms are still unclear. Using a classical contextual fear-conditioning model, we investigated the effect of novelty on long-lasting extinction memory in rats. We found that exposure to a novel environment but not familiar environment 1 h before or after extinction enhanced extinction long-term memory (LTM) and reduced fear reinstatement. However, exploring novelty 6 h before or after extinction had no such effect. Infusion of the β-adrenergic receptor (βAR) inhibitor propranolol and glucocorticoid receptor (GR) inhibitor RU486 into the CA1 area of the dorsal hippocampus before novelty exposure blocked the effect of novelty on extinction memory. Propranolol prevented activation of the hippocampal PKA-CREB pathway, and RU486 prevented activation of the hippocampal extracellular signal-regulated kinase 1/2 (Erk1/2)-CREB pathway induced by novelty exposure. These results indicate that the hippocampal βAR-PKA-CREB and GR-Erk1/2-CREB pathways mediate the extinction-enhancing effect of novelty exposure. Infusion of RU486 or the Erk1/2 inhibitor U0126, but not propranolol or the PKA inhibitor Rp-cAMPS, into the CA1 before extinction disrupted the formation of extinction LTM, suggesting that hippocampal GR and Erk1/2 but not βAR or PKA play critical roles in this process. These results indicate that novelty promotes extinction memory via hippocampal βAR- and GR-dependent pathways, and Erk1/2 may serve as a behavioral tag of extinction. Copyright © 2015 the authors 0270-6474/15/358308-14$15.00/0.

  19. Down-Regulation of Vitamin D Receptor in Mammospheres: Implications for Vitamin D Resistance in Breast Cancer and Potential for Combination Therapy

    PubMed Central

    Pervin, Shehla; Hewison, Martin; Braga, Melissa; Tran, Lac; Chun, Rene; Karam, Amer; Chaudhuri, Gautam; Norris, Keith; Singh, Rajan

    2013-01-01

    Vitamin D signaling in mammary cancer stem cells (MCSCs), which are implicated in the initiation and progression of breast cancer, is poorly understood. In this study, we examined vitamin D signaling in mammospheres which are enriched in MCSCs from established breast cancer cell lines. Breast cancer cells positive for aldehyde dehydrogenase (ALDH+) had increased ability to form mammospheres compared to ALDH− cells. These mammospheres expressed MCSC-specific markers and generated transplantable xenografts in nude mice. Vitamin D receptor (VDR) was significantly down-regulated in mammospheres, as well as in ALDH+ breast cancer cells. TN aggressive human breast tumors as well as transplantable xenografts obtained from SKBR3 expressed significantly lower levels of VDR but higher levels of CD44 expression. Snail was up-regulated in mammospheres isolated from breast cancer cells. Inhibition of VDR expression by siRNA led to a significant change in key EMT-specific transcription factors and increased the ability of these cells to form mammospheres. On the other hand, over-expression of VDR led to a down-regulation of Snail but increased expression of E-cad and significantly compromised the ability of cells to form mammospheres. Mammospheres were relatively insensitive to treatment with 1,25-dihydroxyvitamin D (1,25D), the active form of vitamin D, compared to more differentiated cancer cells grown in presence of serum. Treatment of H-Ras transformed HMLEHRas cells with DETA NONOate, a nitric oxide (NO)-donor led to induction of MAP-kinase phosphatase -1 (MKP-1) and dephosphorylation of ERK1/2 in the mammospheres. Combined treatment of these cells with 1,25D and a low-concentration of DETA NONOate led to a significant decrease in the overall size of mammospheres and reduced tumor volume in nude mice. Our findings therefore, suggest that combination therapy using 1,25D with drugs specifically targeting key survival pathways in MCSCs warrant testing in prospective clinical

  20. Down-regulation of vitamin D receptor in mammospheres: implications for vitamin D resistance in breast cancer and potential for combination therapy.

    PubMed

    Pervin, Shehla; Hewison, Martin; Braga, Melissa; Tran, Lac; Chun, Rene; Karam, Amer; Chaudhuri, Gautam; Norris, Keith; Singh, Rajan

    2013-01-01

    Vitamin D signaling in mammary cancer stem cells (MCSCs), which are implicated in the initiation and progression of breast cancer, is poorly understood. In this study, we examined vitamin D signaling in mammospheres which are enriched in MCSCs from established breast cancer cell lines. Breast cancer cells positive for aldehyde dehydrogenase (ALDH(+)) had increased ability to form mammospheres compared to ALDH(-) cells. These mammospheres expressed MCSC-specific markers and generated transplantable xenografts in nude mice. Vitamin D receptor (VDR) was significantly down-regulated in mammospheres, as well as in ALDH(+) breast cancer cells. TN aggressive human breast tumors as well as transplantable xenografts obtained from SKBR3 expressed significantly lower levels of VDR but higher levels of CD44 expression. Snail was up-regulated in mammospheres isolated from breast cancer cells. Inhibition of VDR expression by siRNA led to a significant change in key EMT-specific transcription factors and increased the ability of these cells to form mammospheres. On the other hand, over-expression of VDR led to a down-regulation of Snail but increased expression of E-cad and significantly compromised the ability of cells to form mammospheres. Mammospheres were relatively insensitive to treatment with 1,25-dihydroxyvitamin D (1,25D), the active form of vitamin D, compared to more differentiated cancer cells grown in presence of serum. Treatment of H-Ras transformed HMLE(HRas) cells with DETA NONOate, a nitric oxide (NO)-donor led to induction of MAP-kinase phosphatase -1 (MKP-1) and dephosphorylation of ERK1/2 in the mammospheres. Combined treatment of these cells with 1,25D and a low-concentration of DETA NONOate led to a significant decrease in the overall size of mammospheres and reduced tumor volume in nude mice. Our findings therefore, suggest that combination therapy using 1,25D with drugs specifically targeting key survival pathways in MCSCs warrant testing in prospective

  1. Glucocorticoids induce transactivation of tight junction genes occludin and claudin-5 in retinal endothelial cells via a novel cis-element.

    PubMed

    Felinski, Edward A; Cox, Amy E; Phillips, Brett E; Antonetti, David A

    2008-06-01

    Tight junctions between vascular endothelial cells help to create the blood-brain and blood-retinal barriers. Breakdown of the retinal tight junction complex is problematic in several disease states including diabetic retinopathy. Glucocorticoids can restore and/or preserve the endothelial barrier to paracellular permeability, although the mechanism remains unclear. We show that glucocorticoid treatment of primary retinal endothelial cells increases content of the tight junction proteins occludin and claudin-5, co-incident with an increase in barrier properties of endothelial monolayers. The glucocorticoid receptor antagonist RU486 reverses both the glucocorticoid-stimulated increase in occludin content and the increase in barrier properties. Transcriptional activity from the human occludin and claudin-5 promoters increases in retinal endothelial cells upon glucocorticoid treatment, and is dependent on the glucocorticoid receptor (GR) as demonstrated by siRNA. Deletion analysis of the occludin promoter reveals a 205bp sequence responsible for the glucocorticoid response. However, this region does not possess a canonical glucocorticoid response element and does not bind to the GR in a chromatin immunoprecipitation (ChIP) assay. Mutational analysis of this region revealed a novel 40bp occludin enhancer element (OEE), containing two highly conserved regions of 10 and 13 base pairs, that is both necessary and sufficient for glucocorticoid-induced gene expression in retinal endothelial cells. These data suggest a novel mechanism for glucocorticoid induction of vascular endothelial barrier properties through increased occludin and claudin-5 gene expression.

  2. GLUCOCORTICOIDS INDUCE TRANSACTIVATION OF TIGHT JUNCTION GENES OCCLUDIN AND CLAUDIN-5 IN RETINAL ENDOTHELIAL CELLS VIA A NOVEL CIS-ELEMENT

    PubMed Central

    Felinski, Edward A.; Cox, Amy E.; Phillips, Brett E.; Antonetti, David A.

    2008-01-01

    Tight junctions between vascular endothelial cells help to create the blood-brain and blood-retinal barriers. Breakdown of the retinal tight junction complex is problematic in several disease states including diabetic retinopathy. Glucocorticoids can restore and/or preserve the endothelial barrier to paracellular permeability, although the mechanism remains unclear. We show that glucocorticoid treatment of primary retinal endothelial cells increases content of the tight junction proteins occludin and claudin-5, co-incident with an increase in barrier properties of endothelial monolayers. The glucocorticoid receptor antagonist RU486 reverses both the glucocorticoid-stimulated increase in occludin content and the increase in barrier properties. Transcriptional activity from the human occludin and claudin-5 promoters increases in retinal endothelial cells upon glucocorticoid treatment, and is dependent on the glucocorticoid receptor (GR) as demonstrated by siRNA. Deletion analysis of the occludin promoter reveals a 205 bp sequence responsible for the glucocorticoid response. However, this region does not posses a canonical glucocorticoid response element and does not bind to the GR in a chromatin immunoprecipitation (ChIP) assay. Mutational analysis of this region revealed a novel 40 bp occludin enhancer element (OEE), containing two highly-conserved regions of 10 and 13 base pairs, that is both necessary and sufficient for glucocorticoid-induced gene expression in retinal endothelial cells. These data suggest a novel mechanism for glucocorticoid induction of vascular endothelial barrier properties through increased occludin and claudin-5 gene expression. PMID:18501346

  3. Temporal variability of glucocorticoid receptor activity is functionally important for the therapeutic action of fluoxetine in the hippocampus.

    PubMed

    Lee, M-S; Kim, Y-H; Park, W-S; Park, O-K; Kwon, S-H; Hong, K S; Rhim, H; Shim, I; Morita, K; Wong, D L; Patel, P D; Lyons, D M; Schatzberg, A F; Her, S

    2016-02-01

    Previous studies have shown inconsistent results regarding the actions of antidepressants on glucocorticoid receptor (GR) signalling. To resolve these inconsistencies, we used a lentiviral-based reporter system to directly monitor rat hippocampal GR activity during stress adaptation. Temporal GR activation was induced significantly by acute stress, as demonstrated by an increase in the intra-individual variability of the acute stress group compared with the variability of the non-stress group. However, the increased intra-individual variability was dampened by exposure to chronic stress, which was partly restored by fluoxetine treatment without affecting glucocorticoid secretion. Immobility in the forced-swim test was negatively correlated with the intra-individual variability, but was not correlated with the quantitative GR activity during fluoxetine therapy; this highlights the temporal variability in the neurobiological links between GR signalling and the therapeutic action of fluoxetine. Furthermore, we demonstrated sequential phosphorylation between GR (S224) and (S232) following fluoxetine treatment, showing a molecular basis for hormone-independent nuclear translocation and transcriptional enhancement. Collectively, these results suggest a neurobiological mechanism by which fluoxetine treatment confers resilience to the chronic stress-mediated attenuation of hypothalamic-pituitary-adrenal axis activity.

  4. Dexamethasone Enhances 1α,25-Dihydroxyvitamin D3 Effects by Increasing Vitamin D Receptor Transcription*

    PubMed Central

    Hidalgo, Alejandro A.; Deeb, Kristin K.; Pike, J. Wesley; Johnson, Candace S.; Trump, Donald L.

    2011-01-01

    Calcitriol, the active form of vitamin D, in combination with the glucocorticoid dexamethasone (Dex) has been shown to increase the antitumor effects of calcitriol in squamous cell carcinoma. In this study we found that pretreatment with Dex potentiates calcitriol effects by inhibiting cell growth and increasing vitamin D receptor (VDR) and VDR-mediated transcription. Treatment with actinomycin D inhibits Vdr mRNA synthesis, indicating that Dex regulates VDR expression at transcriptional level. Real time PCR shows that treatment with Dex increases Vdr transcripts in a time- and a dose-dependent manner, indicating that Dex directly regulates expression of Vdr. RU486, an inhibitor of glucocorticoids, inhibits Dex-induced Vdr expression. In addition, the silencing of glucocorticoid receptor (GR) abolishes the induction of Vdr by Dex, indicating that Dex increases Vdr transcripts in a GR-dependent manner. A fragment located 5.2 kb upstream of Vdr transcription start site containing two putative glucocorticoid response elements (GREs) was evaluated using a luciferase-based reporter assay. Treatment with 100 nm Dex induces transcription of luciferase driven by the fragment. Deletion of the GRE distal to transcription start site was sufficient to abolish Dex induction of luciferase. Also, chromatin immunoprecipitation reveals recruitment of GR to distal GRE with Dex treatment. We conclude that Dex increases VDR and vitamin D effects by increasing Vdr de novo transcription in a GR-dependent manner. PMID:21868377

  5. Decoy receptor 3 suppresses RANKL-induced osteoclastogenesis via down-regulating NFATc1 and enhancing cell apoptosis.

    PubMed

    Cheng, Chia-Pi; Sheu, Ming-Jen; Sytwu, Huey-Kang; Chang, Deh-Ming

    2013-04-01

    Decoy receptor 3 (DCR3) has been known to modulate immune functions of monocyte or macrophage. In the present study, we investigated the mechanism and the effect of DCR3 on RANK ligand (RANKL)-induced osteoclastogenesis. We treated cells with DCR3 in RANKL-induced osteoclastogenesis to monitor osteoclast formation by tartrate-resistant acid phosphatase (TRAP) staining. Osteoclast activity was assessed by pit formation assay. The mechanism of inhibition was studied by biochemical analysis such as RT-PCR and immunoblotting. In addition, cell viability was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Cell apoptosis and apoptosis signalling were evaluated by immunoblotting and using flow cytometry. DCR3 inhibited RANKL-induced TRAP(+) multinucleated cells and inhibited RANKL-induced nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) activation and nuclear factor of activated T-cells, cytoplasmic, calcineurin-dependent 1 (NFATc1) nuclear translocation in RAW264.7 cells. Also, DCR3 significantly inhibited the bone-resorbing activity of mature osteoclasts. Moreover, DCR3 enhanced RANKL-induced cell apoptosis and enhanced RANKL-induced Fas ligand expression. The mechanisms were mediated via the intrinsic cytochrome c and activated caspase 9 apoptosis pathway. We postulated that the inhibitory activity of DCR3 on osteoclastogenesis occurs via down-regulation of RANKL-induced NFATc1 expression and induction of cell apoptosis. Our results postulated DCR3 as a possible new remedy against inflammatory bone destruction.

  6. Down-regulation of microRNA-146a is associated with high-risk human papillomavirus infection and epidermal growth factor receptor overexpression in penile squamous cell carcinoma.

    PubMed

    Peta, Elektra; Cappellesso, Rocco; Masi, Giulia; Sinigaglia, Alessandro; Trevisan, Marta; Grassi, Angela; Di Camillo, Barbara; Vassarotto, Elisa; Fassina, Ambrogio; Palù, Giorgio; Barzon, Luisa

    2017-03-01

    Dysregulation of host microRNA expression has been involved in the development and progression of human papillomavirus (HPV)-related tumors. Analysis of miR-146a expression in a series of 59 penile squamous cell carcinomas (PSCCs) showed that its levels were lower in high-risk HPV-positive than in HPV-negative PSCCs and inversely correlated with expression of epidermal growth factor receptor (EGFR), a known target for miR-146a. Analysis of genotype distribution for rs2910164, a common functional polymorphism of miR-146a, did not identify correlations with miR-146a levels and EGFR expression in PSCCs. In vitro experiments demonstrated that E6 of HPV type 16, but not low-risk HPV-6, down-regulated miR-146a in human foreskin keratinocytes and up-regulated EGFR. Ectopic expression of miR-146a decreased expression of EGFR and inhibited proliferation of keratinocytes and cervical carcinoma cells. EGFR is commonly overexpressed in penile cancer and in other squamous cell carcinomas. Molecular mechanisms leading to EGFR overexpression and activation are known for HPV-negative cancers and include amplification or mutations of the EGFR gene. The results of this study indicate that down-regulation of miR-146a may represent another mechanism of EGFR overexpression in PSCCs, which can be mediated by high-risk HPV E6 in HPV-related tumors. Copyright © 2016 Elsevier Inc. All rights reserved.

  7. Intracellular glucocorticoid receptors in spleen, but not skin, vary seasonally in wild house sparrows (Passer domesticus)

    PubMed Central

    Lattin, Christine R.; Waldron-Francis, K.; Romero, L. Michael

    2013-01-01

    Over the short-term and at physiological doses, acute increases in corticosterone (CORT) titres can enhance immune function. There are predictable seasonal patterns in both circulating CORT and immune function across many animal species, but whether CORT receptor density in immune tissues varies seasonally is currently unknown. Using radioligand binding assays, we examined changes in concentrations of glucocorticoid receptors (GR) and mineralocorticoid receptors (MR) in spleen and skin in wild-caught house sparrows in Massachusetts during six different life-history stages: moult, early winter, late winter, pre-egg-laying, breeding and late breeding. Splenic GR and MR binding were highest during the pre-laying period. This may help animals respond to immune threats through increased lymphocyte proliferation and/or an increase in delayed-type hypersensitivity reactions, both of which CORT can stimulate and in which spleen is involved. A decrease in splenic GR and MR during the late breeding period coincides with low baseline and stress-induced CORT, suggesting immune function in spleen may be relatively CORT-independent during this period. We saw no seasonal patterns in GR or MR in skin, suggesting skin's response to CORT is modulated primarily via changes in circulating CORT titres and/or via local production of CORT in response to wounding and other noxious stimuli. PMID:23407837

  8. Membrane-Associated Effects of Glucocorticoid on BACE1 Upregulation and Aβ Generation: Involvement of Lipid Raft-Mediated CREB Activation.

    PubMed

    Choi, Gee Euhn; Lee, Sei-Jung; Lee, Hyun Jik; Ko, So Hee; Chae, Chang Woo; Han, Ho Jae

    2017-08-30

    Glucocorticoid has been widely accepted to induce Alzheimer's disease, but the nongenomic effect of glucocorticoid on amyloid β (Aβ) generation has yet to be studied. Here, we investigated the effect of the nongenomic pathway induced by glucocorticoid on amyloid precursor protein processing enzymes as well as Aβ production using male ICR mice and human neuroblastoma SK-N-MC cells. Mice groups exposed to restraint stress or intracerebroventricular injection of Aβ showed impaired cognition, decreased intracellular glucocorticoid receptor (GR) level, but elevated level of membrane GR (mGR). In this respect, we identified the mGR-dependent pathway evoked by glucocorticoid using impermeable cortisol conjugated to BSA (cortisol-BSA) on SK-N-MC cells. Cortisol-BSA augmented the expression of β-site amyloid precursor protein cleaving enzyme 1 (BACE1), the level of C-terminal fragment β of amyloid precursor protein (C99) and Aβ production, which were maintained even after blocking intracellular GR. We also found that cortisol-BSA enhanced the interaction between mGR and Gαs, which colocalized in the lipid raft. The subsequently activated CREB by cortisol-BSA bound to the CRE site of the BACE1 promoter increasing its expression, which was downregulated by inhibiting CBP. Consistently, blocking CBP attenuated cognitive impairment and Aβ production induced by corticosterone treatment or intracerebroventricular injection of Aβ more efficiently than inhibiting intracellular GR in mice. In conclusion, glucocorticoid couples mGR with Gαs and triggers cAMP-PKA-CREB axis dependent on the lipid raft to stimulate BACE1 upregulation and Aβ generation. SIGNIFICANCE STATEMENT Patients with Alzheimer's disease (AD) have been growing sharply and stress is considered as the major environment factor of AD. Glucocorticoid is the primarily responsive factor to stress and is widely known to induce AD. However, most AD patients usually have impaired genomic pathway of glucocorticoid

  9. Raised urinary glucocorticoid and adrenal androgen precursors in the urine of young hypertensive patients: possible evidence for partial glucocorticoid resistance

    PubMed Central

    Shamim, W; Yousufuddin, M; Francis, D; Gualdiero, P; Honour, J; Anker, S; Coats, A

    2001-01-01

    OBJECTIVE—To evaluate urinary glucocorticoid excretion profiles in a cohort of recently diagnosed young hypertensive patients.
METHODS—After excluding patients with secondary causes, 60 individuals with premature hypertension were recruited (diagnosed by ambulatory blood pressure monitoring before the age of 36 years). In addition, 30 older hypertensive controls (age of onset > 36 years, "middle aged hypertensive controls"), and 30 normal controls (age matched to the young hypertensive group) were studied. All provided 24 hour urine collections for mass spectrometry for total cortisol metabolites and total androgen metabolites by gas chromatography.
RESULTS—Among male patients, those with premature hypertension had higher total urinary excretion of cortisol metabolites (mean (SD), 13 332 (6472) µg/day) than age matched normal controls (7270 (1788) µg/day; p = 0.00001) or middle aged hypertensive controls (8315 (3565) µg/day; p = 0.002). A similar increase was seen among the female patients, although the absolute concentrations were lower. There was no significant difference between middle aged hypertensive patients and normal controls. Urinary total androgen excretion profiles in female patients also showed an unusual increase in the premature hypertension group (2958 (1672) µg/day) compared with the other groups (middle aged hypertensive controls, 1373 (748) µg/day, p = 0.0003; normal controls, 1687 (636) µg/day, p = 0.002). In all subjects, serum sodium and creatinine concentrations were within the normal range; serum potassium concentrations were found to be low before the start of treatment.
CONCLUSIONS—Individuals presenting with premature hypertension have an abnormally high excretion of glucocorticoid metabolites in the urine. While the mechanism remains uncertain, these findings are compatible with partial resistance of the glucocorticoid receptors, with a compensatory increase in cortisol and androgen

  10. Glucocorticoid receptor interacts with PNRC2 in a ligand-dependent manner to recruit UPF1 for rapid mRNA degradation.

    PubMed

    Cho, Hana; Park, Ok Hyun; Park, Joori; Ryu, Incheol; Kim, Jeonghan; Ko, Jesang; Kim, Yoon Ki

    2015-03-31

    Glucocorticoid receptor (GR), which was originally known to function as a nuclear receptor, plays a role in rapid mRNA degradation by acting as an RNA-binding protein. The mechanism by which this process occurs remains unknown. Here, we demonstrate that GR, preloaded onto the 5'UTR of a target mRNA, recruits UPF1 through proline-rich nuclear receptor coregulatory protein 2 (PNRC2) in a ligand-dependent manner, so as to elicit rapid mRNA degradation. We call this process GR-mediated mRNA decay (GMD). Although GMD, nonsense-mediated mRNA decay (NMD), and staufen-mediated mRNA decay (SMD) share upstream frameshift 1 (UPF1) and PNRC2, we find that GMD is mechanistically distinct from NMD and SMD. We also identify de novo cellular GMD substrates using microarray analysis. Intriguingly, GMD functions in the chemotaxis of human monocytes by targeting chemokine (C-C motif) ligand 2 (CCL2) mRNA. Thus, our data provide molecular evidence of a posttranscriptional role of the well-studied nuclear hormone receptor, GR, which is traditionally considered a transcription factor.

  11. Association of the glucocorticoid receptor gene polymorphisms and their interaction with stressful life events in Polish adolescent girls with anorexia nervosa.

    PubMed

    Dmitrzak-Weglarz, Monika; Szczepankiewicz, Aleksandra; Slopien, Agnieszka; Tyszkiewicz, Marta; Maciukiewicz, Malgorzata; Zaremba, Dorota; Twarowska-Hauser, Joanna

    2016-03-01

    Disturbances in stress response mechanisms and hypothalamic-pituitary-adrenal axis (HPA) functioning are considered important factors involved in the pathophysiology of anorexia nervosa (AN). Thus, genetic variations in the end effector of HPA - glucocorticoid receptor gene and relationships to stressful life events (SLE) may be connected to a higher risk of illness. The aim of the study was examining the association between glucocorticoid receptor gene (NR3C1) polymorphisms and risk factors among stressful life events in AN patients. This study comprised 256 patients with AN and 167 control subjects. The questionnaires examining brief history of the mother's pregnancy and long-acting stress factors, as well as life events checklist to assess stressful life events during the 6 months prior to hospitalization were used. The eight common SNPs (rs6198, rs6191, rs6196, rs258813, rs33388, rs41423247, rs56149945 and rs10052957) of NR3C1 gene were genotyped. The association of five polymorphisms (rs6191, rs258813, rs33388, rs41423247 and rs10052957) and one complex allele (TCAGT) of NR3C1 gene with increased risk of AN were found. However, no significant correlations between early, long-acting and predicting hospitalization SLE and any of the analyzed polymorphisms were observed. The results confirm that the NR3C1 gene is associated with AN risk regardless of the type of stressful triggering factors.

  12. Functional effects of polymorphisms on glucocorticoid receptor modulation of human anxiogenic substance-P gene promoter activity in primary amygdala neurones

    PubMed Central

    Hay, Colin W.; Shanley, Lynne; Davidson, Scott; Cowie, Philip; Lear, Marissa; McGuffin, Peter; Riedel, Gernot; McEwan, Iain J.; MacKenzie, Alasdair

    2014-01-01

    Summary Expression or introduction of the neuropeptide substance-P (SP; encoded by the TAC1 gene in humans and Tac1 in rodents) in the amygdala induces anxiety related behaviour in rodents. In addition, pharmacological antagonism of the main receptor of SP in humans; NK1, is anxiolytic. In the current study, we show that the Tac1 locus is up-regulated in primary rat amygdala neurones in response to activation of the glucocorticoid receptor (GR); a classic component of the stress response. Using a combination of bioinformatics, electrophoretic mobility shift assays (EMSA) and reporter plasmid magnetofection into rat primary amygdala neurones we identified a highly conserved GR response sequence (2GR) in the human TAC1 promoter that binds GR in response to dexamethasone (Dex) or forskolin. We also identified a second GR binding site in the human promoter that was polymorphic and whose T-allele is only found in Japanese and Chinese populations. We present evidence that the T-allele of SNPGR increases the activity of the TAC1 promoter through de-sequestration or de-repression of 2GR. The identification of Dex/forskolin response elements in the TAC1 promoter in amygdala neurones suggests a possible link in the chain of molecular events connecting GR activation and anxiety. In addition, the discovery of a SNP which can alter this response may have implications for our understanding of the role of regulatory variation in susceptibility to stress in specific populations. PMID:25001955

  13. Rapamycin up-regulates triglycerides in hepatocytes by down-regulating Prox1.

    PubMed

    Kwon, Sora; Jeon, Ji-Sook; Kim, Su Bin; Hong, Young-Kwon; Ahn, Curie; Sung, Jung-Suk; Choi, Inho

    2016-02-27

    Although the prolonged use of rapamycin may cause unwanted side effects such as hyperlipidemia, the underlying mechanism remains unknown. Prox1 is a transcription factor responsible for the development of several tissues including lymphatics and liver. There is growing evidences that Prox1 participates in metabolism in addition to embryogenesis. However, whether Prox1 is directly related to lipid metabolism is currently unknown. HepG2 human hepatoma cells were treated with rapamycin and total lipids were analyzed by thin layer chromatography. The effect of rapamycin on the expression of Prox1 was determined by western blotting. To investigate the role of Prox1 in triglycerides regulation, siRNA and overexpression system were employed. Rapamycin was injected into mice for 2 weeks and total lipids and proteins in liver were measured by thin layer chromatography and western blot analysis, respectively. Rapamycin up-regulated the amount of triglyceride and down-regulated the expression of Prox1 in HepG2 cells by reducing protein half-life but did not affect its transcript. The loss-of-function of Prox1 was coincident with the increase of triglycerides in HepG2 cells treated with rapamycin. The up-regulation of triglycerides by rapamycin in HepG2 cells reverted to normal levels by the compensation of Prox1 using the overexpression system. Rapamycin also down-regulated Prox1 expression but increased triglycerides in mouse liver. This study suggests that rapamycin can increase the amount of triglycerides by down-regulating Prox1 expression in hepatocytes, which means that the mammalian target of rapamycin (mTOR) signaling is important for the regulation of triglycerides by maintaining Prox1 expression.

  14. Emotion Regulation in Children with Down Syndrome.

    ERIC Educational Resources Information Center

    Smith, Maureen C.; Walden, Tedra A.

    This study presents a preliminary exploration of emotion regulation in a sample of 20 children (ages 3-18 years) with Down Syndrome. Three aspects of emotion regulation (modulation, organization, flexibility) were predicted from emotion variables (affect intensity, affective expression, and autonomy-curiosity and motivation) in backward regression…

  15. Down-regulation of fibroblast growth factor 2 and its co-receptors heparan sulfate proteoglycans by resveratrol underlies the improvement of cardiac dysfunction in experimental diabetes.

    PubMed

    Strunz, Célia Maria Cássaro; Roggerio, Alessandra; Cruz, Paula Lázara; Pacanaro, Ana Paula; Salemi, Vera Maria Cury; Benvenuti, Luiz Alberto; Mansur, Antonio de Pádua; Irigoyen, Maria Cláudia

    2017-02-01

    Cardiac remodeling in diabetes involves cardiac hypertrophy and fibrosis, and fibroblast growth factor 2 (FGF2) is an important mediator of this process. Resveratrol, a polyphenolic antioxidant, reportedly promotes the improvement of cardiac dysfunction in diabetic rats. However, little information exists linking the amelioration of the cardiac function promoted by resveratrol and the expression of FGF2 and its co-receptors, heparan sulfate proteoglycans (HSPGs: Glypican-1 and Syndecan-4), in cardiac muscle of Type 2 diabetic rats. Diabetes was induced experimentally by the injection of streptozotocin and nicotinamide, and the rats were treated with resveratrol for 6 weeks. According to our results, there is an up-regulation of the expression of genes and/or proteins of Glypican-1, Syndecan-4, FGF2, peroxisome proliferator-activated receptor gamma and AMP-activated protein kinase in diabetic rats. On the other hand, resveratrol treatment promoted the attenuation of left ventricular diastolic dysfunction and the down-regulation of the expression of all proteins under study. The trigger for the changes in gene expression and protein synthesis promoted by resveratrol was the presence of diabetes. The negative modulation conducted by resveratrol on FGF2 and HSPGs expression, which are involved in cardiac remodeling, underlies the amelioration of cardiac function. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

  16. Nitric oxide/cGMP pathway signaling actively down-regulates α4β1-integrin affinity: an unexpected mechanism for inducing cell de-adhesion.

    PubMed

    Chigaev, Alexandre; Smagley, Yelena; Sklar, Larry A

    2011-05-17

    Integrin activation in response to inside-out signaling serves as the basis for rapid leukocyte arrest on endothelium, migration, and mobilization of immune cells. Integrin-dependent adhesion is controlled by the conformational state of the molecule, which is regulated by seven-transmembrane Guanine nucleotide binding Protein-Coupled Receptors (GPCRs). α4β1-integrin (CD49d/CD29, Very Late Antigen-4, VLA-4) is expressed on leukocytes, hematopoietic progenitors, stem cells, hematopoietic cancer cells, and others. VLA-4 conformation is rapidly up-regulated by inside-out signaling through Gαi-coupled GPCRs and down-regulated by Gαs-coupled GPCRs. However, other signaling pathways, which include nitric oxide-dependent signaling, have been implicated in the regulation of cell adhesion. The goal of the current report was to study the effect of nitric oxide/cGMP signaling pathway on VLA-4 conformational regulation. Using fluorescent ligand binding to evaluate the integrin activation state on live cells in real-time, we show that several small molecules, which specifically modulate nitric oxide/cGMP signaling pathway, as well as a cell permeable cGMP analog, can rapidly down-modulate binding of a VLA-4 specific ligand on cells pre-activated through three Gαi-coupled receptors: wild type CXCR4, CXCR2 (IL-8RB), and a non-desensitizing mutant of formyl peptide receptor (FPR ΔST). Upon signaling, we detected rapid changes in the ligand dissociation rate. The dissociation rate after inside-out integrin de-activation was similar to the rate for resting cells. In a VLA-4/VCAM-1-specific myeloid cell adhesion system, inhibition of the VLA-4 affinity change by nitric oxide had a statistically significant effect on real-time cell aggregation. We conclude that nitric oxide/cGMP signaling pathway can rapidly down-modulate the affinity state of the VLA-4 binding pocket, especially under the condition of sustained Gαi-coupled GPCR signaling, generated by a non

  17. Down-regulation of muscarinic receptors and the m3 subtype in white-footed mice by dietary exposure to parathion

    USGS Publications Warehouse

    Jett, David A.; Hill, E.F.; Fernando, J.C.; Eldefrawi, M.E.; Eldefrawi, A.T.

    1993-01-01

    The effect of ad libitum dietary exposure (as occurs in the field) to parathion for 14 d was investigated on the muscarinic acetylcholine receptor (mAChR) in brains and submaxillary glands of adults of a field species, the white-footed mouse Peromyscus leucopus. Immunoprecipitation using subtype selective antibodies revealed that the relative ratios of the m1-m5 mAChR subtypes in Peromyscus brain were similar to those in rat brain. There was little variability in acetylcholinesterase (AChE) activity in control mice brains but large variability in 39 exposed mice, resulting from differences in food ingestion and parathion metabolism. Accordingly, data on radioligand binding to mAChRs in each mouse brain were correlated with brain AChE activity in the same mouse, and AChE inhibition served as a biomarker of exposure reflecting in situ paraoxon concentrations. Exposure to parathion for 14 d reduced maximal binding (Bmax) of [3H]quinuclidinyl benzilate ([3H]QNB), [3H]-N-methylscopolamine ([3H]NMS), and [3H]-4-diphenylacetoxy-N-methylpiperidine methiodide ([3H]-4-DAMP) by up to approximately 58% without affecting receptor affinities for these ligands. Maximal reduction in Bmax of [3H]QNB and [3H]-4-DAMP binding occurred in mice with highest AChE inhibition, while equivalent maximal reduction in Bmax of [3H]NMS occurred in mice with only approximately 10% AChE inhibition, without further change at higher parathion doses. This is believed to be due to the hydrophilicity of [3H]NMS, which limits its accessibility to internalized desensitized receptors. In submaxillary glands (mAChRs are predominantly m3 subtype), there were significant dose-dependent reductions in [3H]QNB binding and m3 mRNA levels in exposed mice, revealed by Northern blot analyses. The reduction in m3 receptors is suggested to result mostly from reduced synthesis at the transcription level, rather than from translational or posttranslational events. The data suggest that down-regulation of mAChRs occurs

  18. Efficacy and safety of selective glucocorticoid receptor modulators in comparison to glucocorticoids in arthritis, a systematic review.

    PubMed

    Safy, M; de Hair, M J H; Jacobs, J W G; Buttgereit, F; Kraan, M C; van Laar, J M

    2017-01-01

    Long-term treatment with glucocorticoids (GCs) plays an important role in the management of arthritis patients, although the efficacy/safety balance is unfavorable. Alternatives with less (severe) adverse effects but with good efficacy are needed. Selective GC receptor modulators (SGRMs) are designed to engage the GC receptor with dissociative characteristics: transactivation of genes, which is mainly responsible for unwanted effects, is less strong while trans-repression of genes, reducing inflammation, is maintained. It is expected that SGRMs thus have a better efficacy/safety balance than GCs. A systematic review providing an overview of the evidence in arthritis is lacking. To systematically review the current literature on efficacy and safety of oral SGRMs in comparison to GCs in arthritis. A search was performed in Medline, Embase and the Cochrane Library, from inception dates of databases until May 2017. Experimental studies involving animal arthritis models or human material of arthritis patients, as well as clinical studies in arthritis patients were included, provided they reported original data. All types of arthritis were included. Data was extracted on the SGRM studied and on the GC used as reference standard; the design or setting of the study was extracted as well as the efficacy and safety results. A total of 207 articles was retrieved of which 17 articles were eligible for our analysis. Two studies concerned randomized controlled trials (RCT), five studies were pre-clinical studies using human material, and 10 studies involved pre-clinical animal models (acute and/or chronic arthritis induced in mice or rats). PF-04171327, the only compound investigated in a clinical trial setting, had a better efficacy/safety balance compared to GCs: better clinical anti-inflammatory efficacy and similar safety. Studies assessing both efficacy and safety of SGRMs are scarce. There is limited evidence for dissociation of anti-inflammatory and metabolic effects of

  19. Desensitization and Down Regulation of Muscarinic Acetylcholine Receptors

    DTIC Science & Technology

    1988-06-22

    function, in vitro. This technique offers an easy method to obtain intact differentiated brain cells with minimal diffusion barriers. Preincubation of...neuroblastoma cells (clone NIE- 115 ). This treatment demonstrated that the muscarinic receptors in this neuronal clone can be divided into two types; one...mouse neuroblastoma NlE- 115 cells, and in other tissues, mediated an increase in phosphoinositide hydrolysis. Diacylglycerol is one of the important

  20. Reduced glucocorticoid receptor expression predicts bladder tumor recurrence and progression.

    PubMed

    Ishiguro, Hitoshi; Kawahara, Takashi; Zheng, Yichun; Netto, George J; Miyamoto, Hiroshi

    2014-08-01

    To assess the levels of glucocorticoid receptor (GR) expression in bladder tumors because the status and its prognostic value remain largely unknown. We immunohistochemically stained for GR in bladder tumor and matched non-neoplastic bladder tissue specimens. Overall, GR was positive in 129 (87%) of 149 urothelial tumors, which was significantly (P=.026) lower than in non-neoplastic urothelium (90 [96%] of 94). Forty-two (79%) of 53 low-grade tumors vs 45 (47%) of 96 high-grade carcinomas (P<.001) and 61 (73%) of 84 non-muscle-invasive (NMI) tumors vs 26 (40%) of 65 muscle-invasive (MI) carcinomas (P<.001) were moderately to strongly immunoreactive for GR. Kaplan-Meier and log-rank tests revealed that loss or weak positivity of GR significantly or marginally correlated with recurrence of NMI tumors (P=.025), progression of MI tumors (P=.082), and cancer-specific survival of MI tumors (P=.067). Multivariate analysis identified low GR expression as a strong predictor for recurrence of NMI tumors (P=.034). GR expression was downregulated in bladder tumors compared with nonneoplastic bladder tumors and in high-grade/MI tumors compared with low-grade/NMI tumors. Decreased expression of GR, as an independent prognosticator, predicted recurrence of NMI tumors. These results support experimental evidence suggesting an inhibitory role of GR signals in bladder cancer outgrowth. Copyright© by the American Society for Clinical Pathology.

  1. [Glucocorticoid induced osteoporosis].

    PubMed

    Anić, Branimir; Mayer, Miroslav

    2014-01-01

    Secondary osteoporosis most often develops due to glucocorticoid therapy. Glucocorticoids affect all stages of the bone remodeling cycle, its formation and resorption. Osteoblasts are primarily affected, decreasing their activity and enhancing apoptosis. Patients treated with glucocorticoids have lower bone mineral density and increased fracture risk. Glucocorticoid-induced osteoporosis can be prevented by administering the minimal effective dose of glucocorticoids, calcium and vitamin D supplementation or, if possible, by hormone replace- ment therapy. Moreover, appropriate physical activity should be encouraged. Patients who are at higher risk for low-energy fractures (for example post-menopausal women) have to be actively treated, usually with antiresorptive drugs among which bisphosphonates are currently the first line therapy.

  2. Expression and regulation of CNTF receptor-alpha in the in situ and in oculo grafted adult rat adrenal medulla.

    PubMed

    Förander, P; Brené, S; Strömberg, I

    2000-02-28

    Cultured and transplanted adrenal medullary cells respond to ciliary neurotrophic factor (CNTF) with neurite formation and improved cell survival although the presence of the CNTF receptor-alpha (CNTFRalpha) has been unclear. This study show that CNTFRalpha mRNA was expressed in the postnatal day 1 as well as in the adult rat adrenal medulla. The highest CNTFRalpha mRNA signal was found in the ganglion cells of the adrenal medulla. After transplantation of adrenal medullary tissue the CNTFRalpha mRNA levels were down-regulated in the chromaffin cells. CNTF treatment of grafts did not normalize the receptor levels, but treatment with nerve growth factor (NGF) did. Thus, we demonstrate that CNTFRalpha mRNA is expressed in adrenal medulla, the levels becomes down-regulated after transplantation, but normalized after treatment with NGF.

  3. Long-term continuous corticosterone treatment decreases VEGF receptor-2 expression in frontal cortex.

    PubMed

    Howell, Kristy R; Kutiyanawalla, Ammar; Pillai, Anilkumar

    2011-01-01

    Stress and increased glucocorticoid levels are associated with many neuropsychiatric disorders including schizophrenia and depression. Recently, the role of vascular endothelial factor receptor-2 (VEGFR2/Flk1) signaling has been implicated in stress-mediated neuroplasticity. However, the mechanism of regulation of VEGF/Flk1 signaling under long-term continuous glucocorticoid exposure has not been elucidated. We examined the possible effects of long-term continuous glucocorticoid exposure on VEGF/Flk1 signaling in cultured cortical neurons in vitro, mouse frontal cortex in vivo, and in post mortem human prefrontal cortex of both control and schizophrenia subjects. We found that long-term continuous exposure to corticosterone (CORT, a natural glucocorticoid) reduced Flk1 protein levels both in vitro and in vivo. CORT treatment resulted in alterations in signaling molecules downstream to Flk1 such as PTEN, Akt and mTOR. We demonstrated that CORT-induced changes in Flk1 levels are mediated through glucocorticoid receptor (GR) and calcium. A significant reduction in Flk1-GR interaction was observed following CORT exposure. Interestingly, VEGF levels were increased in cortex, but decreased in serum following CORT treatment. Moreover, significant reductions in Flk1 and GR protein levels were found in postmortem prefrontal cortex samples from schizophrenia subjects. The alterations in VEGF/Flk1 signaling following long-term continuous CORT exposure represents a molecular mechanism of the neurobiological effects of chronic stress.

  4. K20E, an oxidative-coupling compound of methyl caffeate, exhibits anti-angiogenic activities through down-regulations of VEGF and VEGF receptor-2

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Pan, Chun-Hsu; Lin, Wen-Hsin; Chien, Yi-Chung

    Anti-angiogenesis is one of the most popular clinical interventions for cancer chemotherapy. A series of synthesized derivative of methyl caffeate were used to evaluate the anti-angiogenic activity and to investigate possible pharmacological mechanisms in the present study. The most potent anti-angiogenic compound was evaluated in the experiments of murine allograft tumor model and Matrigel plug assay as well as cell models in the human umbilical vascular endothelial cells (HUVECs) and the LLC1 lung cancer cells. Our results suggested that K20E suppressed the tumor growth in the allograft tumor model and exhibited anti-angiogenic activity in Matrigel plug assay. Besides, HUVEC viabilitymore » was found to be significantly reduced by arresting cell cycle at G{sub 2}/M phase and apoptosis. Cell migration, invasion, and tube formation of the HUVECs were also markedly suppressed by K20E treatment. K20E largely down-regulated the intracellular and secreted vascular endothelial growth factor (VEGF) in the LLC1 cancer cells. Besides, VEGF receptor-2 (VEGFR-2) and its downstream signaling cascades (AKT-mTOR and MEK1/2-ERK1/2) as well as gelatinases were all evidently reduced in the HUVECs treated with K20E. Inversely, K20E can up-regulate the expression levels of p53 and p21 proteins in the HUVECs. Based on these results, our study suggested that K20E possessed inhibiting angiogenesis through regulation of VEGF/VEGFR-2 and its downstream signaling cascades in the vascular endothelial cells (VECs). - Highlights: • K20E is an oxidative-coupling compound of methyl caffeate. • K20E exhibits anti-tumor and anti-angiogenesis effects. • K20E suppresses the expressions of VEGF and VEGF receptor-2 (VEGFR-2) proteins. • K20E deactivates VEGFR-2-mediated downstream signaling pathways to inhibit angiogenesis. • K20E up-regulates p53-p21 pathway to induce apoptosis and cell arrest at G2/M phase.« less

  5. Spatial intensity distribution analysis quantifies the extent and regulation of homodimerization of the secretin receptor

    PubMed Central

    Ward, Richard J.; Pediani, John D.; Harikumar, Kaleeckal G.; Miller, Laurence J.

    2017-01-01

    Previous studies have indicated that the G-protein-coupled secretin receptor is present as a homodimer, organized through symmetrical contacts in transmembrane domain IV, and that receptor dimerization is critical for high-potency signalling by secretin. However, whether all of the receptor exists in the dimeric form or if this is regulated is unclear. We used measures of quantal brightness of the secretin receptor tagged with monomeric enhanced green fluorescent protein (mEGFP) and spatial intensity distribution analysis to assess this. Calibration using cells expressing plasma membrane-anchored forms of mEGFP initially allowed us to demonstrate that the epidermal growth factor receptor is predominantly monomeric in the absence of ligand and while wild-type receptor was rapidly converted into a dimeric form by ligand, a mutated form of this receptor remained monomeric. Equivalent studies showed that, at moderate expression levels, the secretin receptor exists as a mixture of monomeric and dimeric forms, with little evidence of higher-order complexity. However, sodium butyrate-induced up-regulation of the receptor resulted in a shift from monomeric towards oligomeric organization. In contrast, a form of the secretin receptor containing a pair of mutations on the lipid-facing side of transmembrane domain IV was almost entirely monomeric. Down-regulation of the secretin receptor-interacting G-protein Gαs did not alter receptor organization, indicating that dimerization is defined specifically by direct protein–protein interactions between copies of the receptor polypeptide, while short-term treatment with secretin had no effect on organization of the wild-type receptor but increased the dimeric proportion of the mutated receptor variant. PMID:28424368

  6. Synergistic Anti-Tumor Activity of EZH2 Inhibitors and Glucocorticoid Receptor Agonists in Models of Germinal Center Non-Hodgkin Lymphomas.

    PubMed

    Knutson, Sarah K; Warholic, Natalie M; Johnston, L Danielle; Klaus, Christine R; Wigle, Tim J; Iwanowicz, Dorothy; Littlefield, Bruce A; Porter-Scott, Margaret; Smith, Jesse J; Moyer, Mikel P; Copeland, Robert A; Pollock, Roy M; Kuntz, Kevin W; Raimondi, Alejandra; Keilhack, Heike

    2014-01-01

    Patients with non-Hodgkin lymphoma (NHL) are treated today with a cocktail of drugs referred to as CHOP (Cyclophosphamide, Hydroxyldaunorubicin, Oncovin, and Prednisone). Subsets of patients with NHL of germinal center origin bear oncogenic mutations in the EZH2 histone methyltransferase. Clinical testing of the EZH2 inhibitor EPZ-6438 has recently begun in patients. We report here that combining EPZ-6438 with CHOP in preclinical cell culture and mouse models results in dramatic synergy for cell killing in EZH2 mutant germinal center NHL cells. Surprisingly, we observe that much of this synergy is due to Prednisolone - a glucocorticoid receptor agonist (GRag) component of CHOP. Dramatic synergy was observed when EPZ-6438 is combined with Prednisolone alone, and a similar effect was observed with Dexamethasone, another GRag. Remarkably, the anti-proliferative effect of the EPZ-6438+GRag combination extends beyond EZH2 mutant-bearing cells to more generally impact germinal center NHL. These preclinical data reveal an unanticipated biological intersection between GR-mediated gene regulation and EZH2-mediated chromatin remodeling. The data also suggest the possibility of a significant and practical benefit of combining EZH2 inhibitors and GRag that warrants further investigation in a clinical setting.

  7. Therapeutic targeting of angiotensin II receptor type 1 to regulate androgen receptor in prostate cancer.

    PubMed

    Takahashi, Satoru; Uemura, Hiroji; Seeni, Azman; Tang, Mingxi; Komiya, Masami; Long, Ne; Ishiguro, Hitoshi; Kubota, Yoshinobu; Shirai, Tomoyuki

    2012-10-01

    With the limited strategies for curative treatment of castration-resistant prostate cancer (CRPC), public interest has focused on the potential prevention of prostate cancer. Recent studies have demonstrated that an angiotensin II receptor blocker (ARB) has the potential to decrease serum prostate-specific antigen (PSA) level and improve performance status in CRPC patients. These facts prompted us to investigate the direct effects of ARBs on prostate cancer growth and progression. Transgenic rat for adenocarcinoma of prostate (TRAP) model established in our laboratory was used. TRAP rats of 3 weeks of age received ARB (telmisartan or candesartan) at the concentration of 2 or 10 mg/kg/day in drinking water for 12 weeks. In vitro analyses for cell growth, ubiquitylation or reporter gene assay were performed using LNCaP cells. We found that both telmisartan and candesartan attenuated prostate carcinogenesis in TRAP rats by augmentation of apoptosis resulting from activation of caspases, inactivation of p38 MAPK and down-regulation of the androgen receptor (AR). Further, microarray analysis demonstrated up-regulation of estrogen receptor β (ERβ) by ARB treatment. In both parental and androgen-independent LNCaP cells, ARB inhibited both cell growth and AR-mediated transcriptional activity. ARB also exerted a mild additional effect on AR-mediated transcriptional activation by the ERβ up-regulation. An intervention study revealed that PSA progression was prolonged in prostate cancer patients given an ARB compared with placebo control. These data provide a new concept that ARBs are promising potential chemopreventive and chemotherapeutic agents for prostate cancer. Copyright © 2012 Wiley Periodicals, Inc.

  8. Tyrosine Kinase Inhibitors Induce Down-Regulation of c-Kit by Targeting the ATP Pocket

    PubMed Central

    Descarpentries, Clotilde; Frisan, Emilie; Adam, Kevin; Verdier, Frederique; Floquet, Célia; Dubreuil, Patrice; Lacombe, Catherine; Fontenay, Michaela; Mayeux, Patrick; Kosmider, Olivier

    2013-01-01

    The stem cell factor receptor (SCF) c-Kit plays a pivotal role in regulating cell proliferation and survival in many cell types. In particular, c-Kit is required for early amplification of erythroid progenitors, while it must disappear from cell surface for the cell entering the final steps of maturation in an erythropoietin-dependent manner. We initially observed that imatinib (IM), an inhibitor targeting the tyrosine kinase activity of c-Kit concomitantly down-regulated the expression of c-Kit and accelerated the Epo-driven differentiation of erythroblasts in the absence of SCF. We investigated the mechanism by which IM or related masitinib (MA) induce c-Kit down-regulation in the human UT-7/Epo cell line. We found that the down-regulation of c-Kit in the presence of IM or MA was inhibited by a pre-incubation with methyl-β-cyclodextrin suggesting that c-Kit was internalized in the absence of ligand. By contrast to SCF, the internalization induced by TKI was independent of the E3 ubiquitin ligase c-Cbl. Furthermore, c-Kit was degraded through lysosomal, but not proteasomal pathway. In pulse-chase experiments, IM did not modulate c-Kit synthesis or maturation. Analysis of phosphotyrosine peptides in UT-7/Epo cells treated or not with IM show that IM did not modify overall tyrosine phosphorylation in these cells. Furthermore, we showed that a T670I mutation preventing the full access of IM to the ATP binding pocket, did not allow the internalization process in the presence of IM. Altogether these data show that TKI-induced internalization of c-Kit is linked to a modification of the integrity of ATP binding pocket. PMID:23637779

  9. Association between methylation of the glucocorticoid receptor gene, childhood maltreatment, and clinical severity in borderline personality disorder.

    PubMed

    Martín-Blanco, Ana; Ferrer, Marc; Soler, Joaquim; Salazar, Juliana; Vega, Daniel; Andión, Oscar; Sanchez-Mora, Cristina; Arranz, Maria Jesús; Ribases, Marta; Feliu-Soler, Albert; Pérez, Víctor; Pascual, Juan Carlos

    2014-10-01

    The hypothalamus-pituitary-adrenal axis (HPA) is essential in the regulation of stress responses. Increased methylation of the promoter region of the glucocorticoid receptor gene (NR3C1) has been described both in subjects with history of childhood trauma and in patients with Borderline Personality Disorder (BPD). However, no data on the possible association between a higher methylation of this gene and clinical severity is available. The aim of this study was to evaluate the association between NR3C1 methylation status, the history of childhood trauma, and current clinical severity in subjects with BPD. A sample of 281 subjects with BPD (diagnosed by SCID-II and DIB-R semi-structured diagnostic interviews) was recruited. Clinical variables included previous hospitalizations, self-injurious behavior, and self-reported history of childhood trauma. DNA was extracted from peripheral blood. The results indicated a significant positive correlation between NR3C1 methylation status and childhood maltreatment (specifically physical abuse). In addition, a positive correlation between methylation status and clinical severity (DIB-R total score and hospitalizations) was observed. These findings suggest that NR3C1 methylation in subjects with BPD may be associated not only with childhood trauma but also with clinical severity, adding new evidence to the involvement of gene-environment interactions in this disorder. Copyright © 2014 Elsevier Ltd. All rights reserved.

  10. Inhibitory effects of forced swim stress and corticosterone on the acquisition but not expression of morphine-induced conditioned place preference: involvement of glucocorticoid receptor in the basolateral amygdala.

    PubMed

    Attarzadeh-Yazdi, Ghassem; Karimi, Sara; Azizi, Pegah; Yazdi-Ravandi, Saeid; Hesam, Soghra; Haghparast, Abbas

    2013-09-01

    Addiction is a common chronic psychiatric disease which represents a global problem and stress has an important role to increase drug addiction and relapse. In the present study, we investigated the effects of physical stress and exogenous corticosterone on the acquisition and expression of morphine-induced conditioned place preference (CPP). Also, we tried to find out the role of glucocorticoid receptors (GRs) of basolateral amygdala (BLA) in this regard. In the CPP paradigm, conditioning score and locomotion activity were recorded by Ethovision software. Male adult rats received forced swim stress (FSS) as a physical stress or corticosterone (10 mg/kg; ip) as a dominant stress hormone in rodents, 10min before morphine injection (5 mg/kg; sc) during three conditioning days (acquisition) or just prior to CPP test in the post-conditioning day (expression). In FSS procedure, animals were forced to swim for 6 min in cylinder filled with water (24-27 °C). To evaluate the role of glucocorticoid receptors in the BLA, different doses of mifepristone (RU38486) as a GR antagonist were injected into the BLA (0.3, 3 and 30 ng/side) during 3-day conditioning phase before FSS or injection of corticosterone in morphine-CPP paradigm. The results showed that FSS and corticosterone reduce the acquisition but not expression of morphine-induced CPP. Moreover, blockade of GRs in the BLA could diminish the inhibitory effects of FSS or corticosterone on the acquisition of morphine-induced CPP. It seems that stress exerts its effect on reward pathway via glucocorticoid receptors in the BLA. Copyright © 2013 Elsevier B.V. All rights reserved.

  11. A novel in vivo receptor occupancy methodology for the glucocorticoid receptor: toward an improved understanding of lung pharmacokinetic/pharmacodynamic relationships.

    PubMed

    Boger, Elin; Ewing, Pär; Eriksson, Ulf G; Fihn, Britt-Marie; Chappell, Michael; Evans, Neil; Fridén, Markus

    2015-05-01

    Investigation of pharmacokinetic/pharmacodynamic (PK/PD) relationships for inhaled drugs is challenging because of the limited possibilities of measuring tissue exposure and target engagement in the lung. The aim of this study was to develop a methodology for measuring receptor occupancy in vivo in the rat for the glucocorticoid receptor (GR) to allow more informative inhalation PK/PD studies. From AstraZeneca's chemical library of GR binders, compound 1 [N-(2-amino-2-oxo-ethyl)-3-[5-[(1R,2S)-2-(2,2-difluoropropanoylamino)-1-(2,3-dihydro-1,4-benzodioxin-6-yl)propoxy]indazol-1-yl]-N-methyl-benzamide] was identified to have properties that are useful as a tracer for GR in vitro. When given at an appropriate dose (30 nmol/kg) to rats, compound 1 functioned as a tracer in the lung and spleen in vivo using liquid chromatography-tandem mass spectrometry bioanalysis. The methodology was successfully used to show the dose-receptor occupancy relationship measured at 1.5 hours after intravenous administration of fluticasone propionate (20, 150, and 750 nmol/kg) as well as to characterize the time profile for receptor occupancy after a dose of 90 nmol/kg i.v. The dose giving 50% occupancy was estimated as 47 nmol/kg. The methodology is novel in terms of measuring occupancy strictly in vivo and by using an unlabeled tracer. This feature confers key advantages, including occupancy estimation not being influenced by drug particle dissolution or binding/dissociation taking place postmortem. In addition, the tracer may be labeled for use in positron emission tomography imaging, thus enabling occupancy estimation in humans as a translatable biomarker of target engagement. Copyright © 2015 by The American Society for Pharmacology and Experimental Therapeutics.

  12. Action control is mediated by prefrontal BDNF and glucocorticoid receptor binding.

    PubMed

    Gourley, Shannon L; Swanson, Andrew M; Jacobs, Andrea M; Howell, Jessica L; Mo, Michelle; Dileone, Ralph J; Koleske, Anthony J; Taylor, Jane R

    2012-12-11

    Stressor exposure biases decision-making strategies from those based on the relationship between actions and their consequences to others restricted by stimulus-response associations. Chronic stressor exposure also desensitizes glucocorticoid receptors (GR) and diminishes motivation to acquire food reinforcement, although causal relationships are largely not established. We show that a history of chronic exposure to the GR ligand corticosterone or acute posttraining GR blockade with RU38486 makes rodents less able to perform actions based on their consequences. Thus, optimal GR binding is necessary for the consolidation of new response-outcome learning. In contrast, medial prefrontal (but not striatal) BDNF can account for stress-related amotivation, in that selective medial prefrontal cortical Bdnf knockdown decreases break-point ratios in a progressive-ratio task. Knockdown also increases vulnerability to RU38486. Despite the role of BDNF in dendritic spine reorganization, deep-layer spine remodeling does not obviously parallel progressive-ratio response patterns, but treatment with the Na(+)-channel inhibitor riluzole reverses corticosteroid-induced motivational deficits and restores prefrontal BDNF expression after corticosterone. We argue that when prefrontal neurotrophin systems are compromised, and GR-mediated hypothalamic-pituitary-adrenal axis feedback is desensitized (as in the case of chronic stress hormone exposure), amotivation and inflexible maladaptive response strategies that contribute to stress-related mood disorders result.

  13. Cytokines Alter Glucocorticoid Receptor Phosphorylation in Airway Cells

    PubMed Central

    Bouazza, Belaid; Krytska, Kateryna; Debba-Pavard, Manel; Amrani, Yassine; Honkanen, Richard E.; Tran, Jennifer

    2012-01-01

    Corticosteroid insensitivity (CSI) represents a profound challenge in managing patients with asthma. We recently demonstrated that short exposure of airway smooth muscle cells (ASMCs) to proasthmatic cytokines drastically reduced their responsiveness to glucocorticoids (GCs), an effect that was partially mediated via interferon regulatory factor-1, suggesting the involvement of additional mechanisms (Am J Respir Cell Mol Biol 2008;38:463–472). Although GC receptor (GR) can be phosphorylated at multiple serines in the N-terminal region, the major phosphorylation sites critical for GR transcriptional activity are serines 211 (Ser211) and 226 (Ser226). We tested the novel hypothesis that cytokine-induced CSI in ASMCs is due to an impaired GR phosphorylation. Cells were treated with TNF-α (10 ng/ml) and IFN-γ (500 UI/ml) for 6 hours and/or fluticasone (100 nm) added 2 hours before. GR was constitutively phosphorylated at Ser226 but not at Ser211 residues. Cytokines dramatically suppressed fluticasone-induced phosphorylation of GR on Ser211 but not on Ser226 residues while increasing the expression of Ser/Thr protein phosphatase (PP)5 but not that of PP1 or PP2A. Transfection studies using a reporter construct containing GC responsive elements showed that the specific small interfering RNA–induced mRNA knockdown of PP5, but not that of PP1 or PP2A, partially prevented the cytokine suppressive effects on GR-meditated transactivation activity. Similarly, cytokines failed to inhibit GC-induced GR-Ser211 phosphorylation when expression of PP5 was suppressed. We propose that the novel mechanism that proasthmatic cytokine-induced CSI in ASMCs is due, in part, to PP5-mediated impairment of GR-Ser211 phosphorylation. PMID:22592921

  14. The association of metabotropic glutamate receptor type 5 with the neuronal Ca2+-binding protein 2 modulates receptor function.

    PubMed

    Canela, Laia; Fernández-Dueñas, Víctor; Albergaria, Catarina; Watanabe, Masahiko; Lluís, Carme; Mallol, Josefa; Canela, Enric I; Franco, Rafael; Luján, Rafael; Ciruela, Francisco

    2009-10-01

    Metabotropic glutamate (mGlu) receptors mediate in part the CNS effects of glutamate. These receptors interact with a large array of intracellular proteins in which the final role is to regulate receptor function. Here, using co-immunoprecipitation and pull-down experiments we showed a close and specific interaction between mGlu(5) receptor and NECAB2 in both transfected human embryonic kidney cells and rat hippocampus. Interestingly, in pull-down experiments increasing concentrations of calcium drastically reduced the ability of these two proteins to interact, suggesting that NECAB2 binds to mGlu(5) receptor in a calcium-regulated manner. Immunoelectron microscopy detection of NECAB2 and mGlu(5) receptor in the rat hippocampal formation indicated that both proteins are codistributed in the same subcellular compartment of pyramidal cells. In addition, the NECAB2/mGlu(5) receptor interaction regulated mGlu(5b)-mediated activation of both inositol phosphate accumulation and the extracellular signal-regulated kinase/mitogen-activated protein kinase pathway. Overall, these findings indicate that NECAB2 by its physical interaction with mGlu(5b) receptor modulates receptor function.

  15. Glucocorticoid receptor is involved in the differential expression of hepatic 3β-hydroxysteroid dehydrogenase between barrows and boars at finishing stage.

    PubMed

    Li, Xian; Cong, Rihua; Yao, Wen; Jia, Yimin; Li, Runsheng; Sun, Zhiyuan; Li, Xi; Zhao, Ruqian

    2018-01-01

    The enzyme 3β-hydroxysteroid dehydrogenase (3β-HSD) plays an important role in androstenone metabolism in pig liver, and its defective expression is related to the development of boar taint. Early age castration is a common practice in many countries to avoid boar taint, yet whether and how castration affects porcine hepatic 3β-HSD expression are still poorly understood. In this study, we aimed to compare the expression of 3β-HSD between intact (boars) and castrated (barrows) male pigs, and to explore the potential factors regulating 3β-HSD transcription. Compared to barrows, boars showed worse carcass quality. Boars had significantly higher levels of serum androstenone (P < 0.01), testosterone (P < 0.01) and hepatic cortisol (P < 0.05), which were contrary to significantly lower expression of 3β-HSD messenger RNA (P < 0.01) and protein (P < 0.01) in the liver. Significant differences were detected for the hepatic expression of androgen receptor (AR) and CCAAT/enhancer binding protein β (C/EBPβ). Chromatin immunoprecipitation (ChIP) assay demonstrated reduced histone H3 acetylation (P < 0.05) but increased glucocorticoid receptor (GR) binding to 3β-HSD gene promoter in boars (P < 0.05). These results indicate that GR binding to 3β-HSD promoter is involved in the differential hepatic 3β-HSD expression between boars and barrows. © 2017 Japanese Society of Animal Science.

  16. Forced swim stress but not exogenous corticosterone could induce the reinstatement of extinguished morphine conditioned place preference in rats: involvement of glucocorticoid receptors in the basolateral amygdala.

    PubMed

    Karimi, Sara; Attarzadeh-Yazdi, Ghassem; Yazdi-Ravandi, Saeid; Hesam, Soghra; Azizi, Pegah; Razavi, Yasaman; Haghparast, Abbas

    2014-05-01

    Addiction is a common psychiatric disease and stress has an important role in the drug seeking and relapse behaviors. The involvement of basolateral amygdala (BLA) in the effects of stress on reward pathway is discussed in several studies. In this study, we tried to find out the involvement of glucocorticoid receptors (GRs) in the BLA in stress-induced reinstatement of extinguished morphine-induced conditioned place preference (CPP) in rats. The CPP paradigm was done in adult male Wistar rats weighing 220-320 g, and conditioning score and locomotor activity were recorded by Ethovision software. Animals received effective dose of morphine (5mg/kg) daily, during the 3-day conditioning phase. In extinction phase, rats were put in the CPP box for 30 min a day for 8 days. After extinction, animals were injected by corticosterone (10 m/kg) or exposed to forced swim stress (FSS) 10 min before subcutaneous administration of ineffective dose of morphine (0.5mg/kg) in order to reinstate the extinguished morphine-CPP. To block the glucocorticoid receptors in the BLA, after stereotaxic surgery and placing two cannulae in this area bilaterally, animals received GR antagonist mifepristone (RU38486; 0.3, 3 and 30 ng/0.3 μl DMSO per side) prior to exposure to FSS then each animal received ineffective dose of morphine (0.5mg/kg) as drug-induced reinstatement. The results revealed that physical stress (FSS) but not exogenous corticosterone can significantly induce reinstatement of extinguished morphine-CPP, and intra-BLA mifepristone prevents the stress-induced reinstatement. It can be proposed that stress partially exerts its effect on the reward pathway via glucocorticoid receptors in the BLA. Copyright © 2014 Elsevier B.V. All rights reserved.

  17. Inducible somatic embryogenesis in Theobroma cacao achieved using the DEX-activatable transcription factor-glucocorticoid receptor fusion.

    PubMed

    Shires, Morgan E; Florez, Sergio L; Lai, Tina S; Curtis, Wayne R

    2017-11-01

    To carry out mass propagation of superior plants to improve agricultural and silvicultural production though advancements in plant cell totipotency, or the ability of differentiated somatic plant cells to regenerate an entire plant. The first demonstration of a titratable control over somatic embryo formation in a commercially relevant plant, Theobroma cacao (Chocolate tree), was achieved using a dexamethasone activatable chimeric transcription factor. This four-fold enhancement in embryo production rate utilized a glucocorticoid receptor fused to an embryogenic transcription factor LEAFY COTYLEDON 2. Where previous T. cacao somatic embryogenesis has been restricted to dissected flower parts, this construct confers an unprecedented embryogenic potential to leaves. Activatable chimeric transcription factors provide a means for elucidating the regulatory cascade associated with plant somatic embryogenesis towards improving its use for somatic regeneration of transgenics and plant propagation.

  18. Stress and glucocorticoid receptor-dependent mechanisms in long-term memory: from adaptive responses to psychopathologies

    PubMed Central

    Finsterwald, Charles; Alberini, Cristina M.

    2013-01-01

    A proper response against stressors is critical for survival. In mammals, the stress response is primarily mediated by secretion of glucocorticoids via the hypothalamic-pituitaryadrenocortical (HPA) axis and release of catecholamines through adrenergic neurotransmission. Activation of these pathways results in a quick physical response to the stress and, in adaptive conditions, mediates long-term changes in the brain that lead to the formation of long-term memories of the experience. These long-term memories are an essential adaptive mechanism that allows an animal to effectively face similar demands again. Indeed, a moderate stress level has a strong positive effect on memory and cognition, as a single arousing or moderately stressful event can be remembered for up to a lifetime. Conversely, exposure to extreme, traumatic, or chronic stress can have the opposite effect and cause memory loss, cognitive impairments, and stress-related psychopathologies such as anxiety disorders, depression and post-traumatic stress disorder (PTSD). While more effort has been devoted to the understanding of the effects of the negative effects of chronic stress, much less has been done thus far on the identification of the mechanisms engaged in the brain when stress promotes long-term memory formation. Understanding these mechanisms will provide critical information for use in ameliorating memory processes in both normal and pathological conditions. Here, we will review the role of glucocorticoids and glucocorticoid receptors (GRs) in memory formation and modulation. Furthermore, we will discuss recent findings on the molecular cascade of events underlying the effect of GR activation in adaptive levels of stress that leads to strong, long-lasting memories. Our recent data indicate that the positive effects of GR activation on memory consolidation critically engage the brain-derived neurotrophic factor (BDNF) pathway. We propose and will discuss the hypothesis that stress promotes the

  19. SMILE, a new orphan nuclear receptor SHP-interacting protein, regulates SHP-repressed estrogen receptor transactivation.

    PubMed

    Xie, Yuan-Bin; Lee, Ok-Hee; Nedumaran, Balachandar; Seong, Hyun-A; Lee, Kyeong-Min; Ha, Hyunjung; Lee, In-Kyu; Yun, Yungdae; Choi, Hueng-Sik

    2008-12-15

    SHP (small heterodimer partner) is a well-known NR (nuclear receptor) co-regulator. In the present study, we have identified a new SHP-interacting protein, termed SMILE (SHP-interacting leucine zipper protein), which was previously designated as ZF (Zhangfei) via a yeast two-hybrid system. We have determined that the SMILE gene generates two isoforms [SMILE-L (long isoform of SMILE) and SMILE-S (short isoform of SMILE)]. Mutational analysis has demonstrated that the SMILE isoforms arise from the alternative usage of initiation codons. We have confirmed the in vivo interaction and co-localization of the SMILE isoforms and SHP. Domain-mapping analysis indicates that the entire N-terminus of SHP and the middle region of SMILE-L are involved in this interaction. Interestingly, the SMILE isoforms counteract the SHP repressive effect on the transactivation of ERs (estrogen receptors) in HEK-293T cells (human embryonic kidney cells expressing the large T-antigen of simian virus 40), but enhance the SHP-repressive effect in MCF-7, T47D and MDA-MB-435 cells. Knockdown of SMILE gene expression using siRNA (small interfering RNA) in MCF-7 cells increases ER-mediated transcriptional activity. Moreover, adenovirus-mediated overexpression of SMILE and SHP down-regulates estrogen-induced mRNA expression of the critical cell-cycle regulator E2F1. Collectively, these results indicate that SMILE isoforms regulate the inhibition of ER transactivation by SHP in a cell-type-specific manner and act as a novel transcriptional co-regulator in ER signalling.

  20. Regulation of cell growth by redox-mediated extracellular proteolysis of platelet-derived growth factor receptor beta.

    PubMed

    Okuyama, H; Shimahara, Y; Kawada, N; Seki, S; Kristensen, D B; Yoshizato, K; Uyama, N; Yamaoka, Y

    2001-07-27

    Redox-regulated processes are important elements in various cellular functions. Reducing agents, such as N-acetyl-l-cysteine (NAC), are known to regulate signal transduction and cell growth through their radical scavenging action. However, recent studies have shown that reactive oxygen species are not always involved in ligand-stimulated intracellular signaling. Here, we report a novel mechanism by which NAC blocks platelet-derived growth factor (PDGF)-induced signaling pathways in hepatic stellate cells, a fibrogenic player in the liver. Unlike in vascular smooth muscle cells, we found that reducing agents, including NAC, triggered extracellular proteolysis of PDGF receptor-beta, leading to desensitization of hepatic stellate cells toward PDGF-BB. This effect was mediated by secreted mature cathepsin B. In addition, type II transforming growth factor-beta receptor was also down-regulated. Furthermore, these events seemed to cause a dramatic improvement of rat liver fibrosis. These results indicated that redox processes impact the cell's response to growth factors by regulating the turnover of growth factor receptors and that "redox therapy" is promising for fibrosis-related disease.

  1. Peroxisome proliferator-activated receptor alpha (PPARalpha) agonists down-regulate alpha2-macroglobulin expression by a PPARalpha-dependent mechanism.

    EPA Science Inventory

    Peroxisome proliferator-activated receptor alpha (PPARα) regulates transcription of genes involved both in lipid and glucose metabolism as well as inflammation. Fibrates are PPARα ligands used to normalize lipid and glucose parameters and exert anti-inflammatory effects. Fibrates...

  2. Suppression of B-cell development genes is key to glucocorticoid efficacy in treatment of acute lymphoblastic leukemia.

    PubMed

    Kruth, Karina A; Fang, Mimi; Shelton, Dawne N; Abu-Halawa, Ossama; Mahling, Ryan; Yang, Hongxing; Weissman, Jonathan S; Loh, Mignon L; Müschen, Markus; Tasian, Sarah K; Bassik, Michael C; Kampmann, Martin; Pufall, Miles A

    2017-06-01

    Glucocorticoids (GCs), including dexamethasone (dex), are a central component of combination chemotherapy for childhood B-cell precursor acute lymphoblastic leukemia (B-ALL). GCs work by activating the GC receptor (GR), a ligand-induced transcription factor, which in turn regulates genes that induce leukemic cell death. Which GR-regulated genes are required for GC cytotoxicity, which pathways affect their regulation, and how resistance arises are not well understood. Here, we systematically integrate the transcriptional response of B-ALL to GCs with a next-generation short hairpin RNA screen to identify GC-regulated "effector" genes that contribute to cell death, as well as genes that affect the sensitivity of B-ALL cells to dex. This analysis reveals a pervasive role for GCs in suppression of B-cell development genes that is linked to therapeutic response. Inhibition of phosphatidylinositol 3-kinase δ (PI3Kδ), a linchpin in the pre-B-cell receptor and interleukin 7 receptor signaling pathways critical to B-cell development (with CAL-101 [idelalisib]), interrupts a double-negative feedback loop, enhancing GC-regulated transcription to synergistically kill even highly resistant B-ALL with diverse genetic backgrounds. This work not only identifies numerous opportunities for enhanced lymphoid-specific combination chemotherapies that have the potential to overcome treatment resistance, but is also a valuable resource for understanding GC biology and the mechanistic details of GR-regulated transcription. © 2017 by The American Society of Hematology.

  3. Preventing local regeneration of glucocorticoids by 11β-hydroxysteroid dehydrogenase type 1 enhances angiogenesis

    PubMed Central

    Small, Gary R.; Hadoke, Patrick W. F.; Sharif, Isam; Dover, Anna R.; Armour, Danielle; Kenyon, Christopher J.; Gray, Gillian A.; Walker, Brian R.

    2005-01-01

    Angiogenesis restores blood flow to healing tissues, a process that is inhibited by high doses of glucocorticoids. However, the role of endogenous glucocorticoids and the potential for antiglucocorticoid therapy to enhance angiogenesis is unknown. Using in vitro and in vivo models of angiogenesis in mice, we examined effects of (i) endogenous glucocorticoids, (ii) blocking endogenous glucocorticoid action with the glucocorticoid receptor antagonist RU38486, and (iii) abolishing local regeneration of glucocorticoids by the enzyme 11β-hydroxysteroid dehydrogenase type 1 (11βHSD1). Glucocorticoids, administered at physiological concentrations, inhibited angiogenesis in an in vitro aortic ring model and in vivo in polyurethane sponges implanted s.c. RU38486-enhanced angiogenesis in s.c. sponges, in healing surgical wounds, and in the myocardium of mice 7 days after myocardial infarction induced by coronary artery ligation. 11βHSD1 knockout mice showed enhanced angiogenesis in vitro and in vivo within sponges, wounds, and infarcted myocardium. Endogenous glucocorticoids, including those generated locally by 11βHSD1, exert tonic inhibition of angiogenesis. Inhibition of 11βHSD1 in liver and adipose has been advocated to reduce cardiovascular risk in the metabolic syndrome: these data suggest that 11βHSD1 inhibition offers a previously uncharacterized therapeutic approach to improve healing of ischemic or injured tissue. PMID:16093320

  4. Phospholipid Regulation of the Nuclear Receptor Superfamily

    PubMed Central

    Crowder, Mark K.; Seacrist, Corey D.; Blind, Raymond D.

    2016-01-01

    Nuclear receptors are ligand-activated transcription factors whose diverse biological functions are classically regulated by cholesterol-based small molecules. Over the past few decades, a growing body of evidence has demonstrated that phospholipids and other similar amphipathic molecules can also specifically bind and functionally regulate the activity of certain nuclear receptors, suggesting a critical role for these non-cholesterol-based molecules in transcriptional regulation. Phosphatidylcholines, phosphoinositides and sphingolipids are a few of the many phospholipid like molecules shown to quite specifically regulate nuclear receptors in mouse models, cell lines and in vitro. More recent evidence has also shown that certain nuclear receptors can “present” a bound phospholipid headgroup to key lipid signaling enzymes, which can then modify the phospholipid headgroup with very unique kinetic properties. Here, we review the broad array of phospholipid / nuclear receptor interactions, from the perspective of the chemical nature of the phospholipid, and the cellular abundance of the phospholipid. We also view the data in the light of well established paradigms for phospholipid mediated transcriptional regulation, as well as newer models of how phospholipids might effect transcription in the acute regulation of complex nuclear signaling pathways. Thus, this review provides novel insight into the new, non-membrane associated roles nuclear phospholipids play in regulating complex nuclear events, centered on the nuclear receptor superfamily of transcription factors. PMID:27838257

  5. Brain region- and sex-specific modulation of mitochondrial glucocorticoid receptor phosphorylation in fluoxetine treated stressed rats: effects on energy metabolism.

    PubMed

    Adzic, Miroslav; Lukic, Iva; Mitic, Milos; Djordjevic, Jelena; Elaković, Ivana; Djordjevic, Ana; Krstic-Demonacos, Marija; Matić, Gordana; Radojcic, Marija

    2013-12-01

    Antidepressants affect glucocorticoid receptor (GR) functioning partly through modulation of its phosphorylation but their effects on mitochondrial GR have remained undefined. We investigated the ability of chronic fluoxetine treatment to affect chronic stress-induced changes of mitochondrial GR and its phosphoisoforms (pGRs) in the prefrontal cortex and hippocampus of female and male rats. Since mitochondrial GR regulates oxidative phosphorylation, expression of mitochondrial-encoded subunits of cytochrome (cyt) c oxidase and its activity were also investigated. Chronic stress caused accumulation of the GR in mitochondria of female prefrontal cortex, while the changes in the hippocampus were sex-specific at the levels of pGRs. Expression of mitochondrial COXs genes corresponded to chronic stress-modulated mitochondrial GR in both tissues of both genders and to cyt c oxidase activity in females. Moreover, the metabolic parameters in stressed animals were affected by fluoxetine therapy only in the hippocampus. Namely, fluoxetine effects on mitochondrial COXs and cyt c oxidase activity in the hippocampus seem to be conveyed through pGR232 in females, while in males this likely occurs through other mechanisms. In summary, sex-specific regulation of cyt c oxidase by the stress and antidepressant treatment and its differential convergence with mitochondrial GR signaling in the prefrontal cortex and hippocampus could contribute to clarification of sex-dependent vulnerability to stress-related disorders and sex-specific clinical impact of antidepressants. Copyright © 2013 Elsevier Ltd. All rights reserved.

  6. Association between allelic variants of the human glucocorticoid receptor gene and autoimmune diseases: A systematic review and meta-analysis.

    PubMed

    Herrera, Cristian; Marcos, Miguel; Carbonell, Cristina; Mirón-Canelo, José Antonio; Espinosa, Gerard; Cervera, Ricard; Chamorro, Antonio-Javier

    2018-05-01

    The human glucocorticoid receptor gene (NR3C1) is considered to play a role in the differences and sensitivities of the glucocorticoid response in individuals with autoimmune diseases. The objective of this study was to examine by means of a systematic review previous findings regarding allelic variants of NR3C1 in relation to the risk of developing systemic autoimmune diseases. Studies that analysed the genotype distribution of NR3C1 allelic variants among patients with systemic autoimmune diseases were retrieved. A meta-analysis was conducted with a random effects model. Odds ratios (ORs) and their confidence intervals (CIs) were calculated. In addition, sub-analysis by ethnicity, sensitivity analysis and tests for heterogeneity of the results were performed. Eleven studies met the inclusion criteria for meta-analysis. We found no evidence that the analysed NR3C1 polymorphisms, rs6198, rs56149945, and rs6189/rs6190, modulate the risk of developing a systemic autoimmune disease. Nonetheless, a protective role for the minor allele of rs41423247 was found among Caucasians (OR=0.78; 95% CI: 0.65, 0.92; P=0.004). A subgroup analysis according to underlying diseases revealed no significant association either for Behçet's disease or rheumatoid arthritis, while correlations between NR3C1 polymorphisms and disease activity or response to glucocorticoids could not be evaluated due to insufficient data. There is no clear evidence that the analysed NR3C1 allelic variants confer a risk for developing systemic autoimmune diseases although the minor G allele of rs41423247 may be protective among Caucasians. Copyright © 2018 Elsevier B.V. All rights reserved.

  7. Functional effects of polymorphisms on glucocorticoid receptor modulation of human anxiogenic substance-P gene promoter activity in primary amygdala neurones.

    PubMed

    Hay, Colin W; Shanley, Lynne; Davidson, Scott; Cowie, Philip; Lear, Marissa; McGuffin, Peter; Riedel, Gernot; McEwan, Iain J; MacKenzie, Alasdair

    2014-09-01

    Expression or introduction of the neuropeptide substance-P (SP; encoded by the TAC1 gene in humans and Tac1 in rodents) in the amygdala induces anxiety related behaviour in rodents. In addition, pharmacological antagonism of the main receptor of SP in humans; NK1, is anxiolytic. In the current study, we show that the Tac1 locus is up-regulated in primary rat amygdala neurones in response to activation of the glucocorticoid receptor (GR); a classic component of the stress response. Using a combination of bioinformatics, electrophoretic mobility shift assays (EMSA) and reporter plasmid magnetofection into rat primary amygdala neurones we identified a highly conserved GR response sequence (2GR) in the human TAC1 promoter that binds GR in response to dexamethasone (Dex) or forskolin. We also identified a second GR binding site in the human promoter that was polymorphic and whose T-allele is only found in Japanese and Chinese populations. We present evidence that the T-allele of SNPGR increases the activity of the TAC1 promoter through de-sequestration or de-repression of 2GR. The identification of Dex/forskolin response elements in the TAC1 promoter in amygdala neurones suggests a possible link in the chain of molecular events connecting GR activation and anxiety. In addition, the discovery of a SNP which can alter this response may have implications for our understanding of the role of regulatory variation in susceptibility to stress in specific populations. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

  8. Phosphatase inhibitors remove the run-down of γ-aminobutyric acid type A receptors in the human epileptic brain

    PubMed Central

    Palma, E.; Ragozzino, D. A.; Di Angelantonio, S.; Spinelli, G.; Trettel, F.; Martinez-Torres, A.; Torchia, G.; Arcella, A.; Di Gennaro, G.; Quarato, P. P.; Esposito, V.; Cantore, G.; Miledi, R.; Eusebi, F.

    2004-01-01

    The properties of γ-aminobutyric acid (GABA) type A receptors (GABAA receptors) microtransplanted from the human epileptic brain to the plasma membrane of Xenopus oocytes were compared with those recorded directly from neurons, or glial cells, in human brains slices. Cell membranes isolated from brain specimens, surgically obtained from six patients afflicted with drug-resistant temporal lobe epilepsy (TLE) were injected into frog oocytes. Within a few hours, these oocytes acquired GABAA receptors that generated GABA currents with an unusual run-down, which was inhibited by orthovanadate and okadaic acid. In contrast, receptors derived from membranes of a nonepileptic hippocampal uncus, membranes from mouse brain, or recombinant rat α1β2γ2-GABA receptors exhibited a much less pronounced GABA-current run-down. Moreover, the GABAA receptors of pyramidal neurons in temporal neocortex slices from the same six epileptic patients exhibited a stronger run-down than the receptors of rat pyramidal neurons. Interestingly, the GABAA receptors of neighboring glial cells remained substantially stable after repetitive activation. Therefore, the excessive GABA-current run-down observed in the membrane-injected oocytes recapitulates essentially what occurs in neurons, rather than in glial cells. Quantitative RT-PCR analyses from the same TLE neocortex specimens revealed that GABAA-receptor β1, β2, β3, and γ2 subunit mRNAs were significantly overexpressed (8- to 33-fold) compared with control autopsy tissues. Our results suggest that an abnormal GABA-receptor subunit transcription in the TLE brain leads to the expression of run-down-enhanced GABAA receptors. Blockage of phosphatases stabilizes the TLE GABAA receptors and strengthens GABAergic inhibition. It may be that this process can be targeted to develop new treatments for intractable epilepsy. PMID:15218107

  9. NUDT2 Disruption Elevates Diadenosine Tetraphosphate (Ap4A) and Down-Regulates Immune Response and Cancer Promotion Genes

    PubMed Central

    Marriott, Andrew S.; Vasieva, Olga; Fang, Yongxiang; Copeland, Nikki A.; McLennan, Alexander G.; Jones, Nigel J.

    2016-01-01

    Regulation of gene expression is one of several roles proposed for the stress-induced nucleotide diadenosine tetraphosphate (Ap4A). We have examined this directly by a comparative RNA-Seq analysis of KBM-7 chronic myelogenous leukemia cells and KBM-7 cells in which the NUDT2 Ap4A hydrolase gene had been disrupted (NuKO cells), causing a 175-fold increase in intracellular Ap4A. 6,288 differentially expressed genes were identified with P < 0.05. Of these, 980 were up-regulated and 705 down-regulated in NuKO cells with a fold-change ≥ 2. Ingenuity® Pathway Analysis (IPA®) was used to assign these genes to known canonical pathways and functional networks. Pathways associated with interferon responses, pattern recognition receptors and inflammation scored highly in the down-regulated set of genes while functions associated with MHC class II antigens were prominent among the up-regulated genes, which otherwise showed little organization into major functional gene sets. Tryptophan catabolism was also strongly down-regulated as were numerous genes known to be involved in tumor promotion in other systems, with roles in the epithelial-mesenchymal transition, proliferation, invasion and metastasis. Conversely, some pro-apoptotic genes were up-regulated. Major upstream factors predicted by IPA® for gene down-regulation included NFκB, STAT1/2, IRF3/4 and SP1 but no major factors controlling gene up-regulation were identified. Potential mechanisms for gene regulation mediated by Ap4A and/or NUDT2 disruption include binding of Ap4A to the HINT1 co-repressor, autocrine activation of purinoceptors by Ap4A, chromatin remodeling, effects of NUDT2 loss on transcript stability, and inhibition of ATP-dependent regulatory factors such as protein kinases by Ap4A. Existing evidence favors the last of these as the most probable mechanism. Regardless, our results suggest that the NUDT2 protein could be a novel cancer chemotherapeutic target, with its inhibition potentially exerting

  10. NUDT2 Disruption Elevates Diadenosine Tetraphosphate (Ap4A) and Down-Regulates Immune Response and Cancer Promotion Genes.

    PubMed

    Marriott, Andrew S; Vasieva, Olga; Fang, Yongxiang; Copeland, Nikki A; McLennan, Alexander G; Jones, Nigel J

    2016-01-01

    Regulation of gene expression is one of several roles proposed for the stress-induced nucleotide diadenosine tetraphosphate (Ap4A). We have examined this directly by a comparative RNA-Seq analysis of KBM-7 chronic myelogenous leukemia cells and KBM-7 cells in which the NUDT2 Ap4A hydrolase gene had been disrupted (NuKO cells), causing a 175-fold increase in intracellular Ap4A. 6,288 differentially expressed genes were identified with P < 0.05. Of these, 980 were up-regulated and 705 down-regulated in NuKO cells with a fold-change ≥ 2. Ingenuity® Pathway Analysis (IPA®) was used to assign these genes to known canonical pathways and functional networks. Pathways associated with interferon responses, pattern recognition receptors and inflammation scored highly in the down-regulated set of genes while functions associated with MHC class II antigens were prominent among the up-regulated genes, which otherwise showed little organization into major functional gene sets. Tryptophan catabolism was also strongly down-regulated as were numerous genes known to be involved in tumor promotion in other systems, with roles in the epithelial-mesenchymal transition, proliferation, invasion and metastasis. Conversely, some pro-apoptotic genes were up-regulated. Major upstream factors predicted by IPA® for gene down-regulation included NFκB, STAT1/2, IRF3/4 and SP1 but no major factors controlling gene up-regulation were identified. Potential mechanisms for gene regulation mediated by Ap4A and/or NUDT2 disruption include binding of Ap4A to the HINT1 co-repressor, autocrine activation of purinoceptors by Ap4A, chromatin remodeling, effects of NUDT2 loss on transcript stability, and inhibition of ATP-dependent regulatory factors such as protein kinases by Ap4A. Existing evidence favors the last of these as the most probable mechanism. Regardless, our results suggest that the NUDT2 protein could be a novel cancer chemotherapeutic target, with its inhibition potentially exerting

  11. BMP6 down-regulates GDNF expression through SMAD1/5 and ERK1/2 signaling pathways in human granulosa-lutein cells.

    PubMed

    Zhang, Xin-Yue; Chang, Hsun-Ming; Taylor, Elizabeth L; Leung, Peter C K; Liu, Rui-Zhi

    2018-05-09

    Bone morphogenetic protein 6 (BMP6) is a critical regulator of follicular development that is expressed in mammalian oocytes and granulosa cells. Glial cell line-derived neurotrophic factor (GDNF) is an intraovarian neurotrophic factor that plays an essential role in regulating mammalian oocyte maturation. The aim of this study was to investigate the effect of BMP6 on the regulation of GDNF expression and the potential underlying mechanisms. We used an established immortalized human granulosa cell line (SVOG cells) and primary human granulosa-lutein cells as in vitro cell models. Our results showed that BMP6 significantly down-regulated the expression of GDNF in both SVOG and primary human granulosa-lutein cells. Using dual inhibition approaches (kinase receptor inhibitor and small interfering RNA knockdown), our results showed that both ALK2 and ALK3 are involved in BMP6-induced down-regulation of GDNF. In addition, BMP6 induced the phosphorylation of SMAD1/5/8 and ERK1/2 but not AKT or p38. Among three downstream mediators, both SMAD1 and SMAD5 are involved in BMP6-induced down-regulation of GDNF. Moreover, concomitant knockdown of endogenous SMAD4 and inhibition of ERK1/2 activity completely reversed BMP6-induced down-regulation of GDNF, indicating that both SMAD and ERK1/2 signaling pathways are required for the regulatory effect of BMP6 on GDNF expression. Our findings suggest an additional role for an intrafollicular growth factor in regulating follicular function through their paracrine interactions in human granulosa cells.

  12. Discrimination between NL1- and NL2-Mediated Nuclear Localization of the Glucocorticoid Receptor

    PubMed Central

    Savory, Joanne G. A.; Hsu, Brian; Laquian, Ian R.; Giffin, Ward; Reich, Terry; Haché, Robert J. G.; Lefebvre, Yvonne A.

    1999-01-01

    Glucocorticoid receptor (GR) cycles between a free liganded form that is localized to the nucleus and a heat shock protein (hsp)-immunophilin-complexed, unliganded form that is usually localized to the cytoplasm but that can also be nuclear. In addition, rapid nucleocytoplasmic exchange or shuttling of the receptor underlies its localization. Nuclear import of liganded GR is mediated through a well-characterized sequence, NL1, adjacent to the receptor DNA binding domain and a second, uncharacterized motif, NL2, that overlaps with the ligand binding domain. In this study we report that rapid nuclear import (half-life [t1/2] of 4 to 6 min) of agonist- and antagonist-treated GR and the localization of unliganded, hsp-associated GRs to the nucleus in G0 are mediated through NL1 and correlate with the binding of GR to pendulin/importin α. By contrast, NL2-mediated nuclear transfer of GR occurred more slowly (t1/2 = 45 min to 1 h), was agonist specific, and appeared to be independent of binding to importin α. Together, these results suggest that NL2 mediates the nuclear import of GR through an alternative nuclear import pathway. Nuclear export of GR was inhibited by leptomycin B, suggesting that the transfer of GR to the cytoplasm is mediated through the CRM1-dependent pathway. Inhibition of GR nuclear export by leptomycin B enhanced the nuclear localization of both unliganded, wild-type GR and hormone-treated NL1− GR. These results highlight that the subcellular localization of both liganded and unliganded GRs is determined, at least in part, by a flexible equilibrium between the rates of nuclear import and export. PMID:9891038

  13. Down-regulation of chicken interleukin-17 receptor A in Eimeria infection

    USDA-ARS?s Scientific Manuscript database

    Both IL-17A and IL-17F are proinflammatory cytokines, which play an important role in intestinal homeostasis through their receptor signaling. In chickens, these two cytokines have been recently characterized, but to date, very little is known about their receptors and their functional activity. Th...

  14. Peripheral and Central Glucocorticoid Signaling Contributes to Positive Energy Balance in Rats.

    PubMed

    Borba, Tássia Karin; Galindo, Lígia Cristina Monteiro; Ferraz-Pereira, Kelli Nogueira; da Silva Aragão, Raquel; Toscano, Ana Elisa; Guzmán-Quevedo, Omar; Manhães-de-Castro, Raul

    2017-06-01

    The obesity epidemic has been the target of several studies to understand its etiology. The pathophysiological processes that take to obesity generally relate to the rupture of energy balance. This imbalance can result from environmental and/or endogenous events. Among the endogenous events, the hypothalamic-pituitary-adrenal axis, which promotes stress response via glucocorticoid activity, is considered a modulator of energy balance. However, it remains controversial whether the increase in plasma levels of glucocorticoids results in a positive or negative energy balance. Furthermore, there are no studies comparing different routes of administration of glucocorticoids in this context. Here, we investigated the effects of intraperitoneal (i.p.) or intracerebroventricular (i.c.v.) administration of a specific agonist for glucocorticoid receptors on food intake and energy expenditure in rats. Sixty-day old rats were treated with i.p. or i.c.v. dexamethasone. Food intake and satiety were evaluated, as well as locomotor activity in order to determine energy expenditure. Both i.p. and i.c.v. dexamethasone increased food intake and decreased energy expenditure. Moreover, i.c.v. dexamethasone delayed the onset of satiety. Together, these results confirm that central glucocorticoid signaling promotes a positive energy balance and supports the role of the glucocorticoid system as the underlying cause of psychological stress-induced obesity. © Georg Thieme Verlag KG Stuttgart · New York.

  15. Interaction of glucocorticoids with FXR/FGF19/FGF21-mediated ileum-liver crosstalk.

    PubMed

    Al-Aqil, Faten A; Monte, Maria J; Peleteiro-Vigil, Ana; Briz, Oscar; Rosales, Ruben; González, Raquel; Aranda, Carlos J; Ocón, Borja; Uriarte, Iker; de Medina, Fermín Sánchez; Martinez-Augustín, Olga; Avila, Matías A; Marín, José J G; Romero, Marta R

    2018-06-06

    At high doses, glucocorticoids (GC) have been associated with enhanced serum bile acids and liver injury. We have evaluated the effect of GC, in the absence of hepatotoxicity, on FXR/FGF91(Fgf15)/FGF21-mediated ileum-liver crosstalk. Rats and mice (wild type and Fxr -/- , Fgf15 -/- and int-Gr -/- strains; the latter with GC receptor (Gr) knockout selective for intestinal epithelial cells), were treated (i.p.) with dexamethasone, prednisolone or budesonide. In both species, high doses of GC caused hepatotoxicity. At a non-hepatotoxic dose, GC induced ileal Fgf15 down-regulation and liver Fgf21 up-regulation, without affecting Fxr expression. Fgf21 mRNA levels correlated with those of several genes involved in glucose and bile acid metabolism. Surprisingly, liver Cyp7a1 was not up-regulated. The expression of factors involved in transcriptional modulation by Fxr and Gr (p300, Drip205, CBP and Smrt) was not affected. Pxr target genes Cyp3a11 and Mrp2 were not up-regulated in liver or intestine. In contrast, the expression of some Pparα target genes in liver (Fgf21, Cyp4a14 and Vanin-1) and intestine (Vanin-1 and Cyp3a11) was altered. In mice with experimental colitis, liver Fgf21 was up-regulated (4.4-fold). HepG2 cells transfection with FGF21 inhibited CYP7A1 promoter (prCYP7A1-Luc2). This was mimicked by pure human FGF21 protein or culture in medium previously conditioned by cells over-expressing FGF21. This response was not abolished by deletion of a putative response element for phosphorylated FGF21 effectors present in prCYP7A1. In conclusion, GC interfere with FXR/FGF19-mediated intestinal control of CYP7A1 expression by the liver and stimulate hepatic secretion of FGF21, which inhibits CYP7A1 promoter through an autocrine mechanism. Copyright © 2018 Elsevier B.V. All rights reserved.

  16. Corticosteroid receptors adopt distinct cyclical transcriptional signatures.

    PubMed

    Le Billan, Florian; Amazit, Larbi; Bleakley, Kevin; Xue, Qiong-Yao; Pussard, Eric; Lhadj, Christophe; Kolkhof, Peter; Viengchareun, Say; Fagart, Jérôme; Lombès, Marc

    2018-05-07

    Mineralocorticoid receptors (MRs) and glucocorticoid receptors (GRs) are two closely related hormone-activated transcription factors that regulate major pathophysiologic functions. High homology between these receptors accounts for the crossbinding of their corresponding ligands, MR being activated by both aldosterone and cortisol and GR essentially activated by cortisol. Their coexpression and ability to bind similar DNA motifs highlight the need to investigate their respective contributions to overall corticosteroid signaling. Here, we decipher the transcriptional regulatory mechanisms that underlie selective effects of MRs and GRs on shared genomic targets in a human renal cellular model. Kinetic, serial, and sequential chromatin immunoprecipitation approaches were performed on the period circadian protein 1 ( PER1) target gene, providing evidence that both receptors dynamically and cyclically interact at the same target promoter in a specific and distinct transcriptional signature. During this process, both receptors regulate PER1 gene by binding as homo- or heterodimers to the same promoter region. Our results suggest a novel level of MR-GR target gene regulation, which should be considered for a better and integrated understanding of corticosteroid-related pathophysiology.-Le Billan, F., Amazit, L., Bleakley, K., Xue, Q.-Y., Pussard, E., Lhadj, C., Kolkhof, P., Viengchareun, S., Fagart, J., Lombès, M. Corticosteroid receptors adopt distinct cyclical transcriptional signatures.

  17. Glucocorticoid Signaling Enhances Expression of Glucose-Sensing Molecules in Immature Pancreatic Beta-Like Cells Derived from Murine Embryonic Stem Cells In Vitro.

    PubMed

    Ghazalli, Nadiah; Wu, Xiaoxing; Walker, Stephanie; Trieu, Nancy; Hsin, Li-Yu; Choe, Justin; Chen, Chialin; Hsu, Jasper; LeBon, Jeanne; Kozlowski, Mark T; Rawson, Jeffrey; Tirrell, David A; Yip, M L Richard; Ku, Hsun Teresa

    2018-06-06

    Pluripotent stem cells may serve as an alternative source of beta-like cells for replacement therapy of type 1 diabetes; however, the beta-like cells generated in many differentiation protocols are immature. The maturation of endogenous beta cells involves an increase in insulin expression starting in late gestation and a gradual acquisition of the abilities to sense glucose and secrete insulin by week 2 after birth in mice; however, what molecules regulate these maturation processes are incompletely known. In this study, we aim to identify small molecules that affect immature beta cells. A cell-based assay, using pancreatic beta-like cells derived from murine embryonic stem (ES) cells harboring a transgene containing an insulin 1-promoter driven enhanced green fluorescent protein reporter, was used to screen a compound library (NIH Clinical Collection-003). Cortisone, a glucocorticoid, was among five positive hit compounds. Quantitative reverse transcription-polymerase chain reaction analysis revealed that glucocorticoids enhance the gene expression of not only insulin 1 but also glucose transporter-2 (Glut2; Slc2a2) and glucokinase (Gck), two molecules important for glucose sensing. Mifepristone, a pharmacological inhibitor of glucocorticoid receptor (GR) signaling, reduced the effects of glucocorticoids on Glut2 and Gck expression. The effects of glucocorticoids on ES-derived cells were further validated in immature primary islets. Isolated islets from 1-week-old mice had an increased Glut2 and Gck expression in response to a 4-day treatment of exogenous hydrocortisone in vitro. Gene deletion of GR in beta cells using rat insulin 2 promoter-driven Cre crossed with GR flox/flox mice resulted in a reduced gene expression of Glut2, but not Gck, and an abrogation of insulin secretion when islets were incubated in 0.5 mM d-glucose and stimulated by 17 mM d-glucose in vitro. These results demonstrate that glucocorticoids positively regulate glucose sensors in

  18. Effects of coumarate 3-hydroxylase down-regulation on lignin structure

    Treesearch

    John Ralph; Takuya Akiyama; Hoon Kim; Fachuang Lu; Paul F. Schatz; Jane M. Marita; Sally A. Ralph; M.S. Srinivasa Reddy; Fang Chen; Richard A. Dixon

    2006-01-01

    Down-regulation of the gene encoding 4-coumarate 3-hydroxylase (C3H) in alfalfa massively but predictably increased the proportion of p-hydroxyphenyl (P) units relative to thenormally dominant guaiacyl (G) and syringyl (S) units Stem levels of up to ~65% P (from wild-type levels of ~1%) resulting from down-regulation of C3H were measured by traditional degradative...

  19. Glucocorticoid-induced Leucine Zipper (GILZ) and Long GILZ Inhibit Myogenic Differentiation and Mediate Anti-myogenic Effects of Glucocorticoids*

    PubMed Central

    Bruscoli, Stefano; Donato, Valerio; Velardi, Enrico; Di Sante, Moises; Migliorati, Graziella; Donato, Rosario; Riccardi, Carlo

    2010-01-01

    Myogenesis is a process whereby myoblasts differentiate and fuse into multinucleated myotubes, the precursors of myofibers. Various signals and factors modulate this process, and glucocorticoids (GCs) are important regulators of skeletal muscle metabolism. We show that glucocorticoid-induced leucine zipper (GILZ), a GC-induced gene, and the newly identified isoform long GILZ (L-GILZ) are expressed in skeletal muscle tissue and in C2C12 myoblasts where GILZ/L-GILZ maximum expression occurs during the first few days in differentiation medium. Moreover, we observed that GC treatment of myoblasts, which increased GILZ/L-GILZ expression, resulted in reduced myotube formation, whereas GILZ and L-GILZ silencing dampened GC effects. Inhibition of differentiation caused by GILZ/L-GILZ overexpression correlated with inhibition of MyoD function and reduced expression of myogenin. Notably, results indicate that GILZ and L-GILZ bind and regulate MyoD/HDAC1 transcriptional activity, thus mediating the anti-myogenic effect of GCs. PMID:20124407

  20. Glucocorticoids, stress, and fertility.

    PubMed

    Whirledge, S; Cidlowski, J A

    2010-06-01

    Modifications of the hypothalamo-pituitary-adrenal axis and associated changes in circulating levels of glucocorticoids form a key component of the response of an organism to stressful challenges. Increased levels of glucocorticoids promote gluconeogenesis, mobilization of amino acids, and stimulation of fat breakdown to maintain circulating levels of glucose necessary to mount a stress response. In addition to profound changes in the physiology and function of multiple tissues, stress and elevated glucocorticoids can also inhibit reproduction, a logical effect for the survival of self. Precise levels of glucocorticoids are required for proper gonadal function; where the balance is disrupted, so is fertility. Glucocorticoids affect gonadal function at multiple levels in hypothalamo-pituitary-gonadal axis: 1) the hypothalamus (to decrease the synthesis and release of gonadotropin-releasing hormone [GnRH]); 2) the pituitary gland (to inhibit the synthesis and release of luteinizing hormone [LH] and follicle stimulating hormone [FSH]); 3) the testis/ovary (to modulate steroidogenesis and/or gametogenesis directly). Furthermore, maternal exposure to prenatal stress or exogenous glucocorticoids can lead to permanent modification of hypothalamo-pituitary-adrenal function and stress-related behaviors in offspring. Glucocorticoids are vital to many aspects of normal brain development, but fetal exposure to superabundant glucocorticoids can result in life-long effects on neuroendocrine function. This review focuses on the molecular mechanisms believed to mediate glucocorticoid inhibition of reproductive functions and the anatomical sites at which these effects take place.

  1. Symbiotic Bacterial Metabolites Regulate Gastrointestinal Barrier Function via the Xenobiotic Sensor PXR and Toll-like Receptor 4

    PubMed Central

    Venkatesh, Madhukumar; Mukherjee, Subhajit; Wang, Hongwei; Li, Hao; Sun, Katherine; Benechet, Alaxandre P.; Qiu, Zhijuan; Maher, Leigh; Redinbo, Matthew R.; Phillips, Robert S.; Fleet, James C.; Kortagere, Sandhya; Mukherjee, Paromita; Fasano, Alessio; Le Ven, Jessica; Nicholson, Jeremy K.; Dumas, Marc E.; Khanna, Kamal M.; Mani, Sridhar

    2014-01-01

    SUMMARY Intestinal microbial metabolites are conjectured to affect mucosal integrity through an incompletely characterized mechanism. Here we showed microbial-specific indoles regulated intestinal barrier function through the xenobiotic sensor, pregnane X receptor (PXR). Indole 3-propionic acid (IPA), in the context of indole, is as a ligand for PXR in vivo, and IPA down-regulated enterocyte TNF–α while up-regulated junctional protein-coding mRNAs. PXR-deficient (Nr1i2−/−) mice showed a distinctly “leaky” gut physiology coupled with up-regulation of the Toll-like receptor (TLR) signaling pathway. These defects in the epithelial barrier were corrected in Nr1i2−/−Tlr4−/− mice. Our results demonstrate that a direct chemical communication between the intestinal symbionts and PXR regulates mucosal integrity through a pathway which involves luminal sensing and signaling by TLR4. PMID:25065623

  2. DNA methylation down-regulates EGFR expression in chicken

    USDA-ARS?s Scientific Manuscript database

    The epidermal growth factor receptor (EGFR), a growth-factor-receptor tyrosine kinase, was found up-regulated in numerous tumors, which provides a good target for cancer therapy. Although it was documented that oncoviruses are responsible for the activation of EGFR in tumors, the impact of Marek’s d...

  3. Chemoresistance induces enhanced adhesion and transendothelial penetration of neuroblastoma cells by down-regulating NCAM surface expression

    PubMed Central

    Blaheta, Roman A; Daher, Frederick H; Michaelis, Martin; Hasenberg, Christoph; Weich, Eva M; Jonas, Dietger; Kotchetkov, Rouslan; Doerr, Hans Willhelm; Cinatl, Jindrich

    2006-01-01

    Background Drug resistance to chemotherapy is often associated with increased malignancy in neuroblastoma (NB). One explanation for the link between resistance and malignancy might be that resistance facilitates cancer progression and invasion. To investigate this hypothesis, adhesion, transendothelial penetration and NCAM (CD56) adhesion receptor expression of drug-resistant versus drug-sensitive NB tumor cells were evaluated. Methods Acquired drug resistance was mimicked by exposing parental UKF-NB-2, UKF-NB-3 or IMR-32 tumor cells to increasing concentrations of vincristine- (VCR) or doxorubicin (DOX) to establish the resistant tumor cell sublines UKF-NB-2VCR, UKF-NB-2DOX, UKF-NB-3VCR, UKF-NB-3DOX, IMR-32VCR and IMR-32DOX. Additionally, the malignant behaviour of UKF-NB-4, which already possessed the intrinsic multidrug resistance (MDR) phenotype, was analyzed. UKF-NB-4 exposed to VCR or DOX were designated UKF-NB-4VCR or UKF-NB-4DOX. Combined phase contrast – reflection interference contrast microscopy was used to separately evaluate NB cell adhesion and penetration. NCAM was analyzed by flow cytometry, western blot and RT-PCR. Results VCR and DOX resistant tumor sublines showed enhanced adhesion and penetration capacity, compared to their drug naïve controls. Strongest effects were seen with UKF-NB-2VCR, UKF-NB-3VCR and IMR-32DOX. DOX or VCR treatment also evoked increased invasive behaviour of UKF-NB-4. The process of accelerated tumor invasion was accompanied by decreased NCAM surface and protein expression, and down-regulation of NCAM coding mRNA. Transfection of UKF-NB-4VCR cells with NCAM cDNA led to a significant receptor up-regulation, paralleled by diminished adhesion to an endothelial cell monolayer. Conclusion It is concluded that NB cells resistant to anticancer drugs acquire increased invasive capacity relative to non-resistant parental cells, and that enhanced invasion is caused by strong down-regulation of NCAM adhesion receptors. PMID

  4. GLUCOCORTICOID TREATMENT—EFFECT ON ADRENAL MEDULLARY CATECHOLAMINE PRODUCTION

    PubMed Central

    Sharara-Chami, Rana I.; Joachim, Maria; Pacak, Karel; Majzoub, Joseph A.

    2016-01-01

    Glucocorticoid and epinephrine are important stress hormones secreted from the adrenal gland during critical illness. Adrenal glucocorticoid stimulates phenylethanolamine N-methyltransferase (PNMT) to convert norepinephrine to epinephrine in the adrenal medulla. Glucocorticoid is sometimes used in catecholamine-resistant septic shock in critically ill patients. By suppressing adrenal glucocorticoid production, glucocorticoid therapy might also reduce the secretion of epinephrine during stress. To investigate this, we used a mouse model subjected to glucocorticoid therapy under basal conditions (experiment 1) and during stress (experiment 2). In experiment 1, pellets containing 0% to 8% dexamethasone were implanted subcutaneously in mice for 4 weeks. In experiment 2, animals received 14 days of intraperitoneal injections of normal saline, low- or high-dose dexamethasone, followed by 2 h of restraint. We found that in experiment 1, adrenal corticosterone did not differ with dexamethasone treatment. Phenylethanolamine N-methyltransferase messenger RNA levels and adrenal catecholamines were highest in the 8% dexamethasone group. Compared with experiment 1, restrained control mice in experiment 2 had high adrenal corticosterone, which decreased with dexamethasone. Phenylethanolamine N-methyltransferase messenger RNA content doubled with restraint but decreased with dexamethasone treatment. As in experiment 1, adrenal catecholamine content increased significantly with dexamethasone treatment. We conclude that without stress, when adrenocorticotropic hormone is low, high doses of exogenous dexamethasone stimulate PNMT and catecholamine synthesis, likely independently of adrenal corticosterone concentration. After stress, adrenocorticotropic hormone levels are elevated, and exogenous dexamethasone suppresses endogenous corticosterone and PNMT production. Nonetheless, catecholamines increase, possibly due to direct neural stimulation, which may override the hormonal

  5. Effects of Selective and Non-Selective Glucocorticoid Receptor II Antagonists on Rapid-Onset Diabetes in Young Rats

    PubMed Central

    Beaudry, Jacqueline L.; Dunford, Emily C.; Teich, Trevor; Zaharieva, Dessi; Hunt, Hazel; Belanoff, Joseph K.; Riddell, Michael C.

    2014-01-01

    The blockade of glucocorticoid (GC) action through antagonism of the glucocorticoid receptor II (GRII) has been used to minimize the undesirable effects of chronically elevated GC levels. Mifepristone (RU486) is known to competitively block GRII action, but not exclusively, as it antagonizes the progesterone receptor. A number of new selective GRII antagonists have been developed, but limited testing has been completed in animal models of overt type 2 diabetes mellitus. Therefore, two selective GRII antagonists (C113176 and C108297) were tested to determine their effects in our model of GC-induced rapid-onset diabetes (ROD). Male Sprague-Dawley rats (∼ six weeks of age) were placed on a high-fat diet (60%), surgically implanted with pellets containing corticosterone (CORT) or wax (control) and divided into five treatment groups. Each group was treated with either a GRII antagonist or vehicle for 14 days after surgery: CORT pellets (400 mg/rat) + antagonists (80 mg/kg/day); CORT pellets + drug vehicle; and wax pellets (control) + drug vehicle. After 10 days of CORT treatment, body mass gain was increased with RU486 (by ∼20% from baseline) and maintained with C113176 administration, whereas rats given C108297 had similar body mass loss (∼15%) to ROD animals. Fasting glycemia was elevated in the ROD animals (>20 mM), normalized completely in animals treated with RU486 (6.2±0.1 mM, p<0.05) and improved in animals treated with C108297 and C113176 (14.0±1.6 and 8.8±1.6 mM, p<0.05 respectively). Glucose intolerance was normalized with RU486 treatment, whereas acute insulin response was improved with RU486 and C113176 treatment. Also, peripheral insulin resistance was attenuated with C113176 treatment along with improved levels of β-cell function while C108297 antagonism only provided modest improvements. In summary, C113176 is an effective agent that minimized some GC-induced detrimental metabolic effects and may provide an alternative to the effective, but non

  6. In vitro assessment of estrogen, androgen, and glucocorticoid bioactivity in a nationwide screen of United States stream waters

    EPA Science Inventory

    In vitro bioassays can identify environmental samples contaminated with bioactive chemicals that interact with steroid receptors and provide a cumulative, effect-based measurement of contamination. We measured in vitro estrogen (ER), androgen (AR), and glucocorticoid receptor (GR...

  7. Bottom-up and top-down emotion generation: implications for emotion regulation

    PubMed Central

    Misra, Supriya; Prasad, Aditya K.; Pereira, Sean C.; Gross, James J.

    2012-01-01

    Emotion regulation plays a crucial role in adaptive functioning and mounting evidence suggests that some emotion regulation strategies are often more effective than others. However, little attention has been paid to the different ways emotions can be generated: from the ‘bottom-up’ (in response to inherently emotional perceptual properties of the stimulus) or ‘top-down’ (in response to cognitive evaluations). Based on a process priming principle, we hypothesized that mode of emotion generation would interact with subsequent emotion regulation. Specifically, we predicted that top-down emotions would be more successfully regulated by a top-down regulation strategy than bottom-up emotions. To test this hypothesis, we induced bottom-up and top-down emotions, and asked participants to decrease the negative impact of these emotions using cognitive reappraisal. We observed the predicted interaction between generation and regulation in two measures of emotional responding. As measured by self-reported affect, cognitive reappraisal was more successful on top-down generated emotions than bottom-up generated emotions. Neurally, reappraisal of bottom-up generated emotions resulted in a paradoxical increase of amygdala activity. This interaction between mode of emotion generation and subsequent regulation should be taken into account when comparing of the efficacy of different types of emotion regulation, as well as when reappraisal is used to treat different types of clinical disorders. PMID:21296865

  8. Thiols decrease cytokine levels and down-regulate the expression of CD30 on human allergen-specific T helper (Th) 0 and Th2 cells

    PubMed Central

    Bengtsson, Å; Lundberg, M; Avila-Cariño, J; Jacobsson, G; Holmgren, A; Scheynius, A

    2001-01-01

    The thiol antioxidant N-acetyl-l-cysteine (NAC), known as a precursor of glutathione (GSH), is used in AIDS treatment trials, as a chemoprotectant in cancer chemotherapy and in treatment of chronic bronchitis. In vitro, GSH and NAC are known to enhance T cell proliferation, production of IL-2 and up-regulation of the IL-2 receptor. The 120-kD CD30 surface antigen belongs to the tumour necrosis factor (TNF) receptor superfamily. It is expressed by activated T helper (Th) cells and its expression is sustained in Th2 cells. We have analysed the effect of GSH and NAC on the cytokine profile and CD30 expression on human allergen-specific T cell clones (TCC). TCC were stimulated with anti-CD3 antibodies in the presence of different concentrations of GSH and NAC. Both thiols caused a dose dependent down-regulation of IL-4, IL-5 and IFN-γ levels in Th0 and Th2 clones, with the most pronounced decrease of IL-4. Furthermore, they down-regulated the surface expression of CD30, and the levels of soluble CD30 (sCD30) in the culture supernatants were decreased. In contrast, the surface expression of CD28 or CD40 ligand (CD40L) was not significantly changed after treatment with 20 mm NAC. These results indicate that GSH and NAC favour a Th1 response by a preferential down-regulation of IL-4. In addition, the expression of CD30 was down regulated by GSH and NAC, suggesting that CD30 expression is dependent on IL-4, or modified by NAC. In the likely event that CD30 and its soluble counterpart prove to contribute to the pathogenesis in Th2 related diseases such as allergy, NAC may be considered as a future therapeutic agent in the treatment of these diseases. PMID:11298119

  9. G protein-coupled receptor 30 regulates trophoblast invasion and its deficiency is associated with preeclampsia.

    PubMed

    Tong, Chao; Feng, Xiang; Chen, Jun; Qi, Xingchen; Zhou, Liyuan; Shi, Shuming; Kc, Kamana; Stanley, Joanna L; Baker, Philip N; Zhang, Hua

    2016-04-01

    Preeclampsia is known to be associated with reduced circulating levels of estrogen. The effects of estrogen in preeclampsia are normally mediated by the classical estrogen receptors. Intriguingly, a novel estrogen receptor, G protein-coupled receptor 30 (GPR30), has been recently found to play an important role in several estrogenic effects. However, the mechanisms by which GPR30 may mediate the development of preeclampsia remain unknown. We observed that the expression of GPR30 in placental trophoblast cells is lower in preeclamptic placentas compared with normotensive controls. We then investigated the role of GPR30 in trophoblast cell invasion by utilizing placental explants and the immortalized human trophoblast cell line (HTR8/SVneo). The selective GPR30 agonist G1 and a general estrogen receptors agonist 17-β-estradiol (E2) both improved trophoblast cells invasion by upregulating MMP9 expression and the PI3K-Akt signaling pathway. This effect was abolished by a selective GPR30 inhibitor G15, implying that GPR30 may be involved in regulating trophoblast invasion, and that down-regulation of this receptor may result in the development of preeclampsia. The present study suggests that GPR30 is a critical regulator of trophoblast cell invasion, and as such may be a potential therapeutic interventional target for preeclampsia and other pregnancy complications resulting from impaired trophoblast invasion.

  10. Phosphorylation status modulates Bcl-2 function during glucocorticoid-induced apoptosis in T lymphocytes.

    PubMed

    Huang, Se-Te J; Cidlowski, John A

    2002-06-01

    Glucocorticoids are known to induce apoptosis in lymphoid cells, and Bcl-2 overexpression can block the apoptosis-inducing action of glucocorticoids. Since phosphorylation of Bcl-2 is implicated in regulating Bcl-2 function, we considered the role of Bcl-2 phosphorylation in protecting lymphoid cells from glucocorticoid-induced cell death. Five stably transfected cell lines of WEHI 7.1 cells expressing either wild-type Bcl-2 or alanine mutants of Bcl-2 at amino acids threonine 56, serine 70, threonine 74, or serine 87 were created. Expression of the mutant Bcl-2 proteins was documented by flow cytometry and Western blot analysis. Mutation of Bcl-2 on T56 and S87 eliminated the ability of Bcl-2 to inhibit glucocorticoid-induced cell shrinkage, mitochondrial depolarization, DNA fragmentation, and cell death. Mutation of T74 only partially impaired the ability of Bcl-2 to block glucocorticoid-induced apoptosis whereas mutation of S70 in Bcl-2 did not alter its ability to block glucocorticoid-induced apoptosis.

  11. Induction of Glucocorticoid-induced Leucine Zipper (GILZ) Contributes to Anti-inflammatory Effects of the Natural Product Curcumin in Macrophages*

    PubMed Central

    Hoppstädter, Jessica; Hachenthal, Nina; Valbuena-Perez, Jenny Vanessa; Lampe, Sebastian; Astanina, Ksenia; Kunze, Michael M.; Bruscoli, Stefano; Riccardi, Carlo; Schmid, Tobias; Diesel, Britta; Kiemer, Alexandra K.

    2016-01-01

    GILZ (glucocorticoid-induced leucine zipper) is inducible by glucocorticoids and plays a key role in their mode of action. GILZ attenuates inflammation mainly by inhibition of NF-κB and mitogen-activated protein kinase activation but does not seem to be involved in the severe side effects observed after glucocorticoid treatment. Therefore, GILZ might be a promising target for new therapeutic approaches. The present work focuses on the natural product curcumin, which has previously been reported to inhibit NF-κB. GILZ was inducible by curcumin in macrophage cell lines, primary human monocyte-derived macrophages, and murine bone marrow-derived macrophages. The up-regulation of GILZ was neither associated with glucocorticoid receptor activation nor with transcriptional induction or mRNA or protein stabilization but was a result of enhanced translation. Because the GILZ 3′-UTR contains AU-rich elements (AREs), we analyzed the role of the mRNA-binding protein HuR, which has been shown to promote the translation of ARE-containing mRNAs. Our results suggest that curcumin treatment induces HuR expression. An RNA immunoprecipitation assay confirmed that HuR can bind GILZ mRNA. In accordance, HuR overexpression led to increased GILZ protein levels but had no effect on GILZ mRNA expression. Our data employing siRNA in LPS-activated RAW264.7 macrophages show that curcumin facilitates its anti-inflammatory action by induction of GILZ in macrophages. Experiments with LPS-activated bone marrow-derived macrophages from wild-type and GILZ knock-out mice demonstrated that curcumin inhibits the activity of inflammatory regulators, such as NF-κB or ERK, and subsequent TNF-α production via GILZ. In summary, our data indicate that HuR-dependent GILZ induction contributes to the anti-inflammatory properties of curcumin. PMID:27629417

  12. An in vitro approach for prioritization and evaluation of chemical effects on glucocorticoid receptor mediated adipogenesis.

    PubMed

    Hartman, Jessica K; Beames, Tyler; Parks, Bethany; Doheny, Daniel; Song, Gina; Efremenko, Alina; Yoon, Miyoung; Foley, Briana; Deisenroth, Chad; McMullen, Patrick D; Clewell, Rebecca A

    2018-05-18

    Rising obesity rates worldwide have socio-economic ramifications. While genetics, diet, and lack of exercise are major contributors to obesity, environmental factors may enhance susceptibility through disruption of hormone homeostasis and metabolic processes. The obesogen hypothesis contends that chemical exposure early in development may enhance adipocyte differentiation, thereby increasing the number of adipocytes and predisposing for obesity and metabolic disease. We previously developed a primary human adipose stem cell (hASC) assay to evaluate the effect of environmental chemicals on PPARG-dependent adipogenesis. Here, the assay was modified to determine the effects of chemicals on the glucocorticoid receptor (GR) pathway. In differentiation cocktail lacking the glucocorticoid agonist dexamethasone (DEX), hASCs do not differentiate into adipocytes. In the presence of GR agonists, adipocyte maturation was observed using phenotypic makers for lipid accumulation, adipokine secretion, and expression of key genes. To evaluate the role of environmental compounds on adipocyte differentiation, progenitor cells were treated with 19 prioritized compounds previously identified by ToxPi as having GR-dependent bioactivity, and multiplexed assays were used to confirm a GR-dependent mode of action. Five chemicals were found to be strong agonists. The assay was also modified to evaluate GR-antagonists, and 8/10 of the hypothesized antagonists inhibited adipogenesis. The in vitro bioactivity data was put into context with extrapolated human steady state concentrations (Css) and clinical exposure data (Cmax). These data support using a human adipose-derived stem cell differentiation assay to test the potential of chemicals to alter human GR-dependent adipogenesis. Copyright © 2017. Published by Elsevier Inc.

  13. Prenatal Exposure to Arsenic and Cadmium Impacts Infectious Disease-Related Genes within the Glucocorticoid Receptor Signal Transduction Pathway

    PubMed Central

    Rager, Julia E.; Yosim, Andrew; Fry, Rebecca C.

    2014-01-01

    There is increasing evidence that environmental agents mediate susceptibility to infectious disease. Studies support the impact of prenatal/early life exposure to the environmental metals inorganic arsenic (iAs) and cadmium (Cd) on increased risk for susceptibility to infection. The specific biological mechanisms that underlie such exposure-mediated effects remain understudied. This research aimed to identify key genes/signal transduction pathways that associate prenatal exposure to these toxic metals with changes in infectious disease susceptibility using a Comparative Genomic Enrichment Method (CGEM). Using CGEM an infectious disease gene (IDG) database was developed comprising 1085 genes with known roles in viral, bacterial, and parasitic disease pathways. Subsequently, datasets collected from human pregnancy cohorts exposed to iAs or Cd were examined in relationship to the IDGs, specifically focusing on data representing epigenetic modifications (5-methyl cytosine), genomic perturbations (mRNA expression), and proteomic shifts (protein expression). A set of 82 infection and exposure-related genes was identified and found to be enriched for their role in the glucocorticoid receptor signal transduction pathway. Given their common identification across numerous human cohorts and their known toxicological role in disease, the identified genes within the glucocorticoid signal transduction pathway may underlie altered infectious disease susceptibility associated with prenatal exposures to the toxic metals iAs and Cd in humans. PMID:25479081

  14. Synergistic Anti-Tumor Activity of EZH2 Inhibitors and Glucocorticoid Receptor Agonists in Models of Germinal Center Non-Hodgkin Lymphomas

    PubMed Central

    Klaus, Christine R.; Wigle, Tim J.; Iwanowicz, Dorothy; Littlefield, Bruce A.; Porter-Scott, Margaret; Smith, Jesse J.; Moyer, Mikel P.; Copeland, Robert A.; Pollock, Roy M.; Kuntz, Kevin W.; Raimondi, Alejandra; Keilhack, Heike

    2014-01-01

    Patients with non-Hodgkin lymphoma (NHL) are treated today with a cocktail of drugs referred to as CHOP (Cyclophosphamide, Hydroxyldaunorubicin, Oncovin, and Prednisone). Subsets of patients with NHL of germinal center origin bear oncogenic mutations in the EZH2 histone methyltransferase. Clinical testing of the EZH2 inhibitor EPZ-6438 has recently begun in patients. We report here that combining EPZ-6438 with CHOP in preclinical cell culture and mouse models results in dramatic synergy for cell killing in EZH2 mutant germinal center NHL cells. Surprisingly, we observe that much of this synergy is due to Prednisolone – a glucocorticoid receptor agonist (GRag) component of CHOP. Dramatic synergy was observed when EPZ-6438 is combined with Prednisolone alone, and a similar effect was observed with Dexamethasone, another GRag. Remarkably, the anti-proliferative effect of the EPZ-6438+GRag combination extends beyond EZH2 mutant-bearing cells to more generally impact germinal center NHL. These preclinical data reveal an unanticipated biological intersection between GR-mediated gene regulation and EZH2-mediated chromatin remodeling. The data also suggest the possibility of a significant and practical benefit of combining EZH2 inhibitors and GRag that warrants further investigation in a clinical setting. PMID:25493630

  15. ATP hydrolysis is essential for Bag-1M-mediated inhibition of the DNA binding by the glucocorticoid receptor

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Hong, Wei, E-mail: hongwei@tijmu.edu.cn; Chen, Linfeng; Liu, Yunde

    2009-12-04

    The 70-kDa heat shock protein (Hsp70) is involved in providing the appropriate conformation of various nuclear hormone receptors, including the glucocorticoid receptor (GR). The Bcl-2 associated athanogene 1M (Bag-1M) is known to downregulate the DNA binding by the GR. Also, Bag-1M interacts with the ATPase domain of Hsp70 to modulate the release of the substrate from Hsp70. In this study, we demonstrate that ATP hydrolysis enhances Bag-1M-mediated inhibition of the DNA binding by the GR. However, the inhibitory effect of Bag-1M was abolished when the intracellular ATP was depleted. In addition, a Bag-1M mutant lacking the interaction with Hsp70 didmore » not influence the GR to bind DNA, suggesting the interaction of Bag-1M with Hsp70 in needed for its negative effect. These results indicate that ATP hydrolysis is essential for Bag-1M-mediated inhibition of the DNA binding by the GR and Hsp70 is a mediator for this process.« less

  16. Promoter methylation of glucocorticoid receptor gene is associated with subclinical atherosclerosis: A monozygotic twin study.

    PubMed

    Zhao, Jinying; An, Qiang; Goldberg, Jack; Quyyumi, Arshed A; Vaccarino, Viola

    2015-09-01

    Endothelial dysfunction assessed by brachial artery flow-mediated dilation (FMD) is a marker of early atherosclerosis. Glucocorticoid receptor gene (NR3C1) regulates many biological processes, including stress response, behavioral, cardiometabolic and immunologic functions. Genetic variants in NR3C1 have been associated with atherosclerosis and related risk factors. This study investigated the association of NR3C1 promoter methylation with FMD, independent of genetic and family-level environmental factors. We studied 84 middle-aged, male-male monozygotic twin pairs recruited from the Vietnam Era Twin Registry. Brachial artery FMD was measured by ultrasound. DNA methylation levels at 22 CpG residues in the NR3C1 exon 1F promoter region were quantified by bisulfite pyrosequencing in genomic DNA isolated from peripheral blood leukocytes. Co-twin control analyses were conducted to examine the association of methylation variation with FMD, adjusting for smoking, physical activity, body mass index, lipids, blood pressure, fasting glucose, and depressive symptoms. Multiple testing was corrected using the false discovery rate. Mean methylation level across the 22 studied CpG sites was 2.02%. Methylation alterations at 12 out of the 22 CpG residues were significantly associated with FMD. On average, a 1% increase in the intra-pair difference in mean DNA methylation was associated with 2.83% increase in the intra-pair difference in FMD (95% CI: 1.46-4.20; P < 0.0001) after adjusting for risk factors and multiple testing. Methylation variation in NR3C1 exon 1F promoter significantly influences subclinical atherosclerosis, independent of genetic, early family environmental and other risk factors. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  17. Cetuximab in combination with anti-human IgG antibodies efficiently down-regulates the EGF receptor by macropinocytosis

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Berger, Christian; Madshus, Inger Helene; Department of Pathology, Oslo University Hospital, Rikshospitalet, Post box 4950 Nydalen, 0424 Oslo

    The monoclonal antibody C225 (Cetuximab) blocks binding of ligand to the epidermal growth factor receptor (EGFR). In addition, it is known that incubation with C225 induces endocytosis of the EGFR. This endocytosis has previously been shown to be increased when C225 is combined with an additional monoclonal anti-EGFR antibody. However, the effects of antibody combinations on EGFR activation, endocytosis, trafficking and degradation have been unclear. By binding a secondary antibody to the C225-EGFR complex, we here demonstrate that a combination of antibodies can efficiently internalize and degrade the EGFR. Although the combination of antibodies activated the EGFR kinase and inducedmore » ubiquitination of the EGFR, the kinase activity was not required for internalization of the EGFR. In contrast to EGF-induced EGFR down-regulation, the antibody combination efficiently degraded the EGFR without initiating downstream proliferative signaling. The antibody-induced internalization of EGFR was found not to depend on clathrin and/or dynamin, but depended on actin polymerization, suggesting induction of macropinocytosis. Macropinocytosis may cause internalization of large membrane areas, and this could explain the highly efficient internalization of the EGFR induced by combination of antibodies. -- Highlight: Black-Right-Pointing-Pointer Cetuximab induced endocytosis of EGFR increases upon combination with anti-human IgG. Black-Right-Pointing-Pointer Antibody combination causes internalization of EGFR by macropinocytosis. Black-Right-Pointing-Pointer Antibody-induced internalization of EGFR is independent of EGFR kinase activity. Black-Right-Pointing-Pointer Antibody combination may have a zipper effect and cross-link EGFRs on neighboring cells.« less

  18. Maternal obesity in the ewe increases cardiac ventricular expression of glucocorticoid receptors, proinflammatory cytokines and fibrosis in adult male offspring

    PubMed Central

    Odhiambo, John F.; McCormick, Richard J.; Nathanielsz, Peter W.; Ford, Stephen P.

    2017-01-01

    Obesity during human pregnancy predisposes offspring to obesity and cardiovascular disease in postnatal life. In a sheep model of maternal overnutrition/obesity we have previously reported myocardial inflammation and fibrosis, as well as cardiac dysfunction in late term fetuses, in association with chronically elevated blood cortisol. Significant research has suggested a link between elevated glucocorticoid exposure in utero and hypertension and cardiovascular disease postnatally. Here we examined the effects of maternal obesity on myocardial inflammation and fibrosis of their adult offspring. Adult male offspring from control (CON) mothers fed 100% of National Research Council (NRC) recommendations (n = 6) and male offspring from obese mothers (MO) fed 150% NRC (n = 6), were put on a 12-week ad libitum feeding challenge then necropsied. At necropsy, plasma cortisol and left and right ventricular thickness were markedly increased (P<0.05) in adult male MO offspring. Myocardial collagen content and collagen-crosslinking were greater (P<0.05) in MO offspring compared to CON offspring in association with increased mRNA and protein expression of glucocorticoid receptors (GR). No group difference was found in myocardial mineralocorticoids receptor (MR) protein expression. Further, mRNA expression for the proinflammatory cytokines: cluster of differentiation (CD)-68, transforming growth factor (TGF)-β1, and tumor necrosis factor (TNF)-α were increased (P < 0.05), and protein expression of CD-68, TGF-β1, and TNF-α tended to increase (P<0.10) in MO vs. CON offspring. These data provide evidence for MO-induced programming of elevated plasma cortisol and myocardial inflammation and fibrosis in adult offspring potentially through increased GR. PMID:29267325

  19. Associations between maternal level of education and occupational status with placental glucocorticoid regeneration and sensitivity.

    PubMed

    Räikkönen, Katri; O'Reilly, James R; Pesonen, Anu-Katriina; Kajantie, Eero; Villa, Pia; Laivuori, Hannele; Hämäläinen, Esa; Seckl, Jonathan R; Reynolds, Rebecca M

    2014-08-01

    Low socio-economic status (SES) is associated with increased disease risk in the involved and the next generation. The effects of low maternal SES on the offspring may be initiated prenatally. We hypothesized that fetoplacental glucocorticoid exposure might mediate the links. We examined associations between maternal level of education and occupational status (used as indices of SES) and placental expression of genes involved in glucocorticoid exposure and transfer between the mother and foetus. Placental biopsies were obtained from 67 healthy women (age 32.2 ± 5.3 years) with singleton, term pregnancies without obstetric complications who participated in a prospective Prediction and Prevention of Preeclampsia (PREDO) study. Level of education was self-reported, and occupational status was extracted from hospital records. Relative glucocorticoid receptor (GR; NR3C1), mineralocorticoid receptor (MR; NR3C2) and 11-beta-hydroxysteroid dehydrogenase type 1 (HSD11B1) and 2 (HSD11B2) mRNA levels were quantified by real-time PCR. Placental GR and HSD11B1 expression increased with decreasing maternal education (unadjusted P-values for linear trend = 0.04 and 0.02 and adjusted P-values = 0.06 and 0.09, respectively). Mothers with primary/secondary education had 52.9% (95% CI, 6.2-99.6, P = 0.03, adjusted P = 0.05) and 79.6% (95% CI, 6.5-153.6, P = 0.03, adjusted P = 0.09) higher GR and HSD11B1 mRNA levels compared with mothers with tertiary education. There were no other significant associations. Lower maternal level of education is associated with increased placental GR and HSD11B1 gene expression. This combination may regenerate active glucocorticoids in placenta and increase placental sensitivity to glucocorticoids, potentially leading to greater placental and foetal glucocorticoid exposure. © 2014 John Wiley & Sons Ltd.

  20. Novel Mechanism for Regulation of Epidermal Growth Factor Receptor Endocytosis Revealed by Protein Kinase A Inhibition

    PubMed Central

    Salazar, Gloria; González, Alfonso

    2002-01-01

    Current models put forward that the epidermal growth factor receptor (EGFR) is efficiently internalized via clathrin-coated pits only in response to ligand-induced activation of its intrinsic tyrosine kinase and is subsequently directed into a lysosomal-proteasomal degradation pathway by mechanisms that include receptor tyrosine phosphorylation and ubiquitylation. Herein, we report a novel mechanism of EGFR internalization that does not require ligand binding, receptor kinase activity, or ubiquitylation and does not direct the receptor into a degradative pathway. Inhibition of basal protein kinase A (PKA) activity by H89 and the cell-permeable substrate peptide Myr-PKI induced internalization of 40–60% unoccupied, inactive EGFR, and its accumulation into early endosomes without affecting endocytosis of transferrin and μ-opioid receptors. This effect was abrogated by interfering with clathrin function. Thus, the predominant distribution of inactive EGFR at the plasma membrane is not simply by default but involves a PKA-dependent restrictive condition resulting in receptor avoidance of endocytosis until it is stimulated by ligand. Furthermore, PKA inhibition may contribute to ligand-induced EGFR endocytosis because epidermal growth factor inhibited 26% of PKA basal activity. On the other hand, H89 did not alter ligand-induced internalization of EGFR but doubled its half-time of down-regulation by retarding its segregation into degradative compartments, seemingly due to a delay in the receptor tyrosine phosphorylation and ubiquitylation. Our results reveal that PKA basal activity controls EGFR function at two levels: 1) residence time of inactive EGFR at the cell surface by a process of “endocytic evasion,” modulating the accessibility of receptors to stimuli; and 2) sorting events leading to the down-regulation pathway of ligand-activated EGFR, determining the length of its intracellular signaling. They add a new dimension to the fine-tuning of EGFR function