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Lv J, Chen YQ, Ding AM, Lei B, Yu J, Gao XM, Dai CB, Sun YH. Control of axillary bud growth in tobacco through toxin gene expression system. Sci Rep 2021; 11:17513. [PMID: 34471163 PMCID: PMC8410782 DOI: 10.1038/s41598-021-96976-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Accepted: 08/11/2021] [Indexed: 11/09/2022] Open
Abstract
The control of axillary bud development after removing the terminal buds (topping) of plants is a research hotspot, and the control of gene expression, like switching on and off, allows us to further study biological traits of interest, such as plant branching and fertility. In this study, a toxin gene control system for plants based on dexamethasone (DEX) induction was constructed, and the positive transgenic tobacco exhibited growth retardation in the application area (axillary bud). The expression level of the lethal Diphtheria toxin A (DTA) gene under different DEX concentrations at different application days was analyzed. The highest expression levels appeared at 5 days after the leaf injection of DEX. The DTA transcripts were induced by 5 µM DEX and peaked in response to 50 µM DEX at 5 days after leaf injection. Here, a chemical induction system, combined with a toxin gene, were used to successfully control the growth of tobacco axillary buds after topping. The DTA expression system under DEX induction was sensitive and efficient, therefore, can be used to control axillary bud growth and development in tobacco.
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Affiliation(s)
- Jing Lv
- Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Qingdao, 266101, China
- Key Laboratory for Tobacco Gene Resources, State Tobacco Monopoly Administration, Qingdao, 266101, China
- Graduate School of Chinese Academy of Agricultural Sciences, Beijing, 100081, China
| | - Ya-Qiong Chen
- Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Qingdao, 266101, China
- Key Laboratory for Tobacco Gene Resources, State Tobacco Monopoly Administration, Qingdao, 266101, China
- Kunming Tobacco Monopoly Administration, Kunming, 650000, China
| | - An-Ming Ding
- Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Qingdao, 266101, China
- Key Laboratory for Tobacco Gene Resources, State Tobacco Monopoly Administration, Qingdao, 266101, China
| | - Bo Lei
- Molecular Genetics Key Laboratory of China Tobacco, Guizhou Academy of Tobacco Science, Guiyang, 550081, China
| | - Jing Yu
- Molecular Genetics Key Laboratory of China Tobacco, Guizhou Academy of Tobacco Science, Guiyang, 550081, China
| | - Xiao-Ming Gao
- Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Qingdao, 266101, China
- Key Laboratory for Tobacco Gene Resources, State Tobacco Monopoly Administration, Qingdao, 266101, China
| | - Chang-Bo Dai
- Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Qingdao, 266101, China.
- Key Laboratory for Tobacco Gene Resources, State Tobacco Monopoly Administration, Qingdao, 266101, China.
| | - Yu-He Sun
- Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Qingdao, 266101, China.
- Key Laboratory for Tobacco Gene Resources, State Tobacco Monopoly Administration, Qingdao, 266101, China.
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Monczor F, Chatzopoulou A, Zappia CD, Houtman R, Meijer OC, Fitzsimons CP. A Model of Glucocorticoid Receptor Interaction With Coregulators Predicts Transcriptional Regulation of Target Genes. Front Pharmacol 2019; 10:214. [PMID: 30930776 PMCID: PMC6425864 DOI: 10.3389/fphar.2019.00214] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Accepted: 02/20/2019] [Indexed: 12/14/2022] Open
Abstract
Regulatory factors that control gene transcription in multicellular organisms are assembled in multicomponent complexes by combinatorial interactions. In this context, nuclear receptors provide well-characterized and physiologically relevant systems to study ligand-induced transcription resulting from the integration of cellular and genomic information in a cell- and gene-specific manner. Here, we developed a mathematical model describing the interactions between the glucocorticoid receptor (GR) and other components of a multifactorial regulatory complex controlling the transcription of GR-target genes, such as coregulator peptides. We support the validity of the model in relation to gene-specific GR transactivation with gene transcription data from A549 cells and in vitro real time quantification of coregulator-GR interactions. The model accurately describes and helps to interpret ligand-specific and gene-specific transcriptional regulation by the GR. The comprehensive character of the model allows future insight into the function and relative contribution of the molecular species proposed in ligand- and gene-specific transcriptional regulation.
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Affiliation(s)
- Federico Monczor
- Laboratorio de Farmacología de Receptores, Instituto de Investigaciones Farmacológicas, Universidad de Buenos Aires-Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina
| | - Antonia Chatzopoulou
- Leiden Academic Center for Drug Research, Leiden University, Leiden, Netherlands
| | - Carlos Daniel Zappia
- Laboratorio de Farmacología de Receptores, Instituto de Investigaciones Farmacológicas, Universidad de Buenos Aires-Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina
| | - René Houtman
- PamGene International B.V., 's-Hertogenbosch, Netherlands
| | - Onno C Meijer
- Division of Endocrinology, Department of Internal Medicine, Leiden University Medical Centre, Leiden, Netherlands
| | - Carlos P Fitzsimons
- Neuroscience Collaboration, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, Netherlands
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Potamitis C, Siakouli D, Papavasileiou KD, Boulaka A, Ganou V, Roussaki M, Calogeropoulou T, Zoumpoulakis P, Alexis MN, Zervou M, Mitsiou DJ. Discovery of New non-steroidal selective glucocorticoid receptor agonists. J Steroid Biochem Mol Biol 2019; 186:142-153. [PMID: 30321666 DOI: 10.1016/j.jsbmb.2018.10.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Revised: 09/19/2018] [Accepted: 10/11/2018] [Indexed: 12/11/2022]
Abstract
Glucocorticoids (GCs) are widely used as potent anti-inflammatory drugs; however, GC therapy is often accompanied by adverse side effects. The anti-inflammatory action of GCs is exerted through the glucocorticoid receptor (GR) in part by antagonizing the pro-inflammatory nuclear factor k B (NF-kB) whereas the majority of side effects are assumed to be mediated by transactivation of GR target genes. We set out to identify novel non-steroidal selective GR agonists (SEGRA) favoring transrepression of NF-kB target genes over transactivation of genes associated with undesirable effects. Our virtual screening protocol was driven by a pharmacophore model based on a pyrrolidinone amide analogue (named as 'compound 12' in Biggadike et al 2009, PNAS USA 106, 18,114) bound to the extended binding pocket of the GR ligand binding domain (GR-LBD). Ambinter library (7.8 million compounds) was queried by our validated pharmacophore hypothesis and the prioritized compounds were biologically evaluated using a series of well-established screening assays. Two structurally similar hits (1 and 13) were identified that bind to GR, induce its translocation to the nucleus, do not mediate transactivation of GR target genes whereas partially repress a number of pro-inflammatory NF-kB target genes, in a GR-dependent manner. Explanatory molecular dynamics (MD) calculations could detail the per-residue interactions accounting for the binding of 1 and 13 to the extended binding pocket of GR. The discovered 1,3-benzothiazole analogs introduce a new class of genuine SEGRA paving the way for hit-to-lead optimization.
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Affiliation(s)
- Constantinos Potamitis
- Institute of Biology, Medicinal Chemistry and Biotechnology, National Hellenic Research Foundation, 48 Vassileos Constantinou Ave., 116 35 Athens, Greece
| | - Dimitra Siakouli
- Institute of Biology, Medicinal Chemistry and Biotechnology, National Hellenic Research Foundation, 48 Vassileos Constantinou Ave., 116 35 Athens, Greece
| | - Konstantinos D Papavasileiou
- Institute of Biology, Medicinal Chemistry and Biotechnology, National Hellenic Research Foundation, 48 Vassileos Constantinou Ave., 116 35 Athens, Greece; National Center for Scientific Research "Demokritos", Institute of Nanoscience and Nanotechnology, Molecular Thermodynamics and Modelling of Materials Laboratory, GR-15310 Aghia Paraskevi Attikis, Greece
| | - Athina Boulaka
- Institute of Biology, Medicinal Chemistry and Biotechnology, National Hellenic Research Foundation, 48 Vassileos Constantinou Ave., 116 35 Athens, Greece
| | - Vassiliki Ganou
- Institute of Biology, Medicinal Chemistry and Biotechnology, National Hellenic Research Foundation, 48 Vassileos Constantinou Ave., 116 35 Athens, Greece
| | - Marina Roussaki
- Institute of Biology, Medicinal Chemistry and Biotechnology, National Hellenic Research Foundation, 48 Vassileos Constantinou Ave., 116 35 Athens, Greece
| | - Theodora Calogeropoulou
- Institute of Biology, Medicinal Chemistry and Biotechnology, National Hellenic Research Foundation, 48 Vassileos Constantinou Ave., 116 35 Athens, Greece
| | - Panagiotis Zoumpoulakis
- Institute of Biology, Medicinal Chemistry and Biotechnology, National Hellenic Research Foundation, 48 Vassileos Constantinou Ave., 116 35 Athens, Greece
| | - Michael N Alexis
- Institute of Biology, Medicinal Chemistry and Biotechnology, National Hellenic Research Foundation, 48 Vassileos Constantinou Ave., 116 35 Athens, Greece
| | - Maria Zervou
- Institute of Biology, Medicinal Chemistry and Biotechnology, National Hellenic Research Foundation, 48 Vassileos Constantinou Ave., 116 35 Athens, Greece.
| | - Dimitra J Mitsiou
- Institute of Biology, Medicinal Chemistry and Biotechnology, National Hellenic Research Foundation, 48 Vassileos Constantinou Ave., 116 35 Athens, Greece.
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Savvidou O, Milonaki M, Goumenos S, Flevas D, Papagelopoulos P, Moutsatsou P. Glucocorticoid signaling and osteoarthritis. Mol Cell Endocrinol 2019; 480:153-166. [PMID: 30445185 DOI: 10.1016/j.mce.2018.11.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Revised: 10/03/2018] [Accepted: 11/11/2018] [Indexed: 01/15/2023]
Abstract
Glucocorticoids are steroid hormones synthesized and released by the adrenal cortex. Their main function is to maintain cell homeostasis through a variety of signaling pathways, responding to changes in an organism's environment or developmental status. Mimicking the actions of natural glucocorticoids, synthetic glucocorticoids have been recruited to treat many diseases that implicate glucocorticoid receptor signaling such as osteoarthritis. In osteoarthritis, synthetic glucocorticoids aim to alleviate inflammation and pain. The variation of patients' response and the possibility of complications associated with their long-term use have led to a need for a better understanding of glucocorticoid receptor signaling in osteoarthritis. In this review, we performed a literature search in the molecular pathways that link the osteoarthritic joint to the glucocorticoid receptor signaling. We hope that this information will advance research in the field and propose new molecular targets for the development of more optimized therapies for osteoarthritis.
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Affiliation(s)
- Olga Savvidou
- First Department of Orthopaedics, National and Kapodistrian University of Athens, School of Medicine, "ATTIKON" University Hospital, Athens, Greece.
| | - Mandy Milonaki
- Department of Clinical Biochemistry, National and Kapodistrian University of Athens, School of Medicine, "ATTIKON" University Hospital, Athens, Greece.
| | - Stavros Goumenos
- First Department of Orthopaedics, National and Kapodistrian University of Athens, School of Medicine, "ATTIKON" University Hospital, Athens, Greece.
| | - Dimitrios Flevas
- First Department of Orthopaedics, National and Kapodistrian University of Athens, School of Medicine, "ATTIKON" University Hospital, Athens, Greece.
| | - Panayiotis Papagelopoulos
- First Department of Orthopaedics, National and Kapodistrian University of Athens, School of Medicine, "ATTIKON" University Hospital, Athens, Greece.
| | - Paraskevi Moutsatsou
- Department of Clinical Biochemistry, National and Kapodistrian University of Athens, School of Medicine, "ATTIKON" University Hospital, Athens, Greece.
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Impact of N-acetylcysteine and sesame oil on lipid metabolism and hypothalamic-pituitary-adrenal axis homeostasis in middle-aged hypercholesterolemic mice. Sci Rep 2014; 4:6806. [PMID: 25348324 PMCID: PMC4210865 DOI: 10.1038/srep06806] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Accepted: 10/07/2014] [Indexed: 12/21/2022] Open
Abstract
Hyperlipidemia and stress are important factors affecting cardiovascular health in middle-aged individuals. We investigated the effects of N-acetylcysteine (NAC) and sesame oil on the lipidemic status, liver architecture and the hypothalamic-pituitary-adrenal (HPA) axis of middle-aged mice fed a cholesterol-enriched diet. We randomized 36 middle-aged C57bl/6 mice into 6 groups: a control group, a cholesterol/cholic acid diet group, a cholesterol/cholic acid diet group with NAC supplementation, a cholesterol/cholic acid diet enriched with 10% sesame oil and two groups receiving a control diet enriched with NAC or sesame oil. NAC administration prevented the onset of the disturbed lipid profile, exhibiting decreased lipid peroxidation and alkaline phosphatase (ALP) levels, restored nitric oxide bioavailability and reduced hepatic damage, compared to non-supplemented groups. High-cholesterol feeding resulted in increased hypothalamic glucocorticoid receptors (GR) levels, while NAC supplementation prevented this effect. NAC supplementation presented significant antioxidant capacity by means of preventing serum lipid status alterations, hepatic damage, and HPA axis disturbance due to high-cholesterol feeding in middle-aged mice. These findings suggest a beneficial preventive action of plant-derived antioxidants, such as NAC, on lipid metabolism and on the HPA axis.
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Bouazza B, Debba-Pavard M, Amrani Y, Isaacs L, O'Connell D, Ahamed S, Formella D, Tliba O. Basal p38 mitogen-activated protein kinase regulates unliganded glucocorticoid receptor function in airway smooth muscle cells. Am J Respir Cell Mol Biol 2014; 50:301-15. [PMID: 24024586 DOI: 10.1165/rcmb.2012-0522oc] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Like many steroid receptors, the glucocorticoid (GC) receptor (GR) is a phosphoprotein. Although there are multiple phosphorylation sites critical for GR transcriptional activity (i.e., serine [S]203, S211, and S226), their respective role in driving GR functions is highly cell specific. We have recently identified protein phosphatase 5 as an essential Ser/Thr phosphatase responsible for impairing GR function via S211 dephosphorylation in airway smooth muscle (ASM) cells. Because p38 mitogen-activated protein kinase (MAPK) directly phosphorylates GR in different cell types in a stimulus- and cell-dependent manner, we investigated the role of p38 MAPK on GR phosphorylation and function in ASM cells. Cells were transfected with 100 nM p38 MAPK small interfering RNA or 2 μg MAPK kinase 3 expression vector (a specific kinase that directly activates p38 MAPK) in the presence or absence of fluticasone (100 nM) and/or p38 MAPK pharmacological inhibitor SB203580. We found that p38 MAPK blockade positively regulates GR nuclear translocation and GR-dependent induction of the steroid-target gene GC-induced leucine zipper in a hormone-independent manner. We also found that p38 MAPK-dependent regulation of GR functions was associated with a differential action on GR phosphorylation at S203 and S211 residues. This study demonstrated that the inactive state of GR in resting conditions is not only ensured by the absence of the GC ligand but also by p38 MAPK-dependent phosphorylation of unliganded GR at specific residues, which appears to be important in determining the overall GC responsiveness of ASM cells.
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Affiliation(s)
- Belaid Bouazza
- 1 Department of Pharmaceutical Sciences, Thomas Jefferson University, Jefferson School of Pharmacy, Philadelphia, Pennsylvania; and
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7
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Pattern of heat shock factor and heat shock protein expression in lymphocytes of bipolar patients: increased HSP70-glucocorticoid receptor heterocomplex. J Psychiatr Res 2013; 47:1725-36. [PMID: 23938235 DOI: 10.1016/j.jpsychires.2013.07.018] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/25/2013] [Revised: 05/22/2013] [Accepted: 07/17/2013] [Indexed: 12/21/2022]
Abstract
Bipolar disorder (BD), a stress-related disease, is characterized by altered glucocorticoid receptor (GR) signalling. Stress response includes activation of heat shock factor (HSF) and subsequent heat shock protein (HSP) synthesis which regulate GR folding and function. The objective of this study was to investigate the possible role of HSFs, HSPs and their interaction with GR in BD. We applied immunoprecipitation, SDS-PAGE/Western blot analysis and electrophoretic mobility shift assay (EMSA) in lymphocytes (whole cell or nuclear extracts) from BD patients and healthy subjects and determined the HSPs (HSP90 and HSP70), the heterocomplexes HSP90-GR and HSP70-GR, the HSFs (HSF1 and HSF4) as well as the HSF-DNA binding. The HSP70-GR heterocomplex was elevated (p < 0.05) in BD patients vs healthy subjects, and nuclear HSP70 was reduced (p ≤ 0.01) in bipolar manic patients. Protein levels of HSF1, HSF4, HSP90, HSP90-GR heterocomplex, and HSF-DNA binding remained unaltered in BD patients vs healthy subjects. The corresponding effect sizes (ES) indicated a large ES for HSP70-GR, HSP70, HSF-DNA binding and HSF4, and a medium ES for HSP90, HSF1 and HSP90-GR between healthy subjects and bipolar patients. Significant correlations among HSFs, HSPs, GR and HSP70-GR heterocomplex were observed in healthy subjects, which were abrogated in bipolar patients. The higher interaction between GR and HSP70 and the disturbances in the relations among heat shock response parameters and GR as observed in our BD patients may provide novel insights into the contribution of these factors in BD aetiopathogenesis.
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Rao NAS, McCalman MT, Moulos P, Francoijs KJ, Chatziioannou A, Kolisis FN, Alexis MN, Mitsiou DJ, Stunnenberg HG. Coactivation of GR and NFKB alters the repertoire of their binding sites and target genes. Genome Res 2011; 21:1404-16. [PMID: 21750107 DOI: 10.1101/gr.118042.110] [Citation(s) in RCA: 160] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Glucocorticoid receptor (GR) exerts anti-inflammatory action in part by antagonizing proinflammatory transcription factors such as the nuclear factor kappa-b (NFKB). Here, we assess the crosstalk of activated GR and RELA (p65, major NFKB component) by global identification of their binding sites and target genes. We show that coactivation of GR and p65 alters the repertoire of regulated genes and results in their association with novel sites in a mutually dependent manner. These novel sites predominantly cluster with p65 target genes that are antagonized by activated GR and vice versa. Our data show that coactivation of GR and NFKB alters signaling pathways that are regulated by each factor separately and provide insight into the networks underlying the GR and NFKB crosstalk.
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Affiliation(s)
- Nagesha A S Rao
- Department of Molecular Biology, Radboud University, Nijmegen, The Netherlands
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Poimenova A, Markaki E, Rahiotis C, Kitraki E. Corticosterone-regulated actions in the rat brain are affected by perinatal exposure to low dose of bisphenol A. Neuroscience 2010; 167:741-9. [DOI: 10.1016/j.neuroscience.2010.02.051] [Citation(s) in RCA: 120] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2009] [Revised: 02/18/2010] [Accepted: 02/19/2010] [Indexed: 10/19/2022]
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10
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Bakos J, Hlavacova N, Rajman M, Ondicova K, Koros C, Kitraki E, Steinbusch H, Jezova D. Enriched environment influences hormonal status and hippocampal brain derived neurotrophic factor in a sex dependent manner. Neuroscience 2009; 164:788-97. [DOI: 10.1016/j.neuroscience.2009.08.054] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2009] [Revised: 08/20/2009] [Accepted: 08/22/2009] [Indexed: 11/27/2022]
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Boukouvalas G, Gerozissis K, Kitraki E. Adult consequences of post-weaning high fat feeding on the limbic-HPA axis of female rats. Cell Mol Neurobiol 2009; 30:521-30. [PMID: 19902349 DOI: 10.1007/s10571-009-9476-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2009] [Accepted: 10/22/2009] [Indexed: 11/27/2022]
Abstract
The peripubertal period is critical for the final maturation of circuits controlling energy homeostasis and stress response. However, the consequence of juvenile fat consumption on adult physiology is not clear. This study analyzed the adult consequences of post-weaning fat feeding on limbic-hypothalamic-pituitary-adrenal (HPA) axis components and on metabolic regulators of female rats. Wistar rats were fed either a high fat (HF) diet or the normal chow from weaning to puberty or to 3 months of age. Additional groups crossed their diets at puberty onset. Plasma leptin, insulin, and corticosterone levels were determined by radioimmunoassay and their brain receptors by western blot analysis. Adult HF-fed animals though not overweight, had higher corticosterone and reduced glucocorticoid receptor levels in the hypothalamus and hippocampus, compared to the controls. The alterations in HPA axis emerged already at puberty onset. Leptin receptor levels in the hypothalamus were reduced only by continuous fat feeding from weaning to adulthood. The pre-pubertal period appeared more vulnerable to diet-induced alterations in adulthood than the post-pubertal one. Switching from fat diet to normal chow at puberty onset restored most of the diet-induced alterations in the HPA axis. The corticosteroid circuit rather than the leptin or insulin system appears as the principal target for the peripubertal fat diet-induced effects in adult female rats.
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Affiliation(s)
- George Boukouvalas
- Laboratory of Histology and Embryology, School of Medicine, University of Athens, Athens, Greece
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Boukouvalas G, Gerozissis K, Kitraki E. Fat feeding of rats during pubertal growth leads to neuroendocrine alterations in adulthood. Cell Mol Neurobiol 2009; 30:91-9. [PMID: 19649701 DOI: 10.1007/s10571-009-9434-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2009] [Accepted: 07/15/2009] [Indexed: 11/30/2022]
Abstract
Juvenile obesity is a rising epidemic due largely to consumption of caloric dense, fat-enriched foods. Nevertheless, literature on fat-induced neuroendocrine and metabolic disturbances during adolescence, preceding obesity, is limited. This study aimed to examine early events induced by a fat diet (45% calories from saturated fat) in male rats fed the diet during the pre- and post-pubertal period. The neuroendocrine endpoints studied were the levels of circulating leptin, insulin and corticosterone, as well as their receptors in the hypothalamus and hippocampus. Hormonal levels were determined by radioimmunoassay and receptors' levels by western blot analysis. Leptinemia was increased in pubertal rats and in adult rats fed the fat diet from weaning to adulthood, but not in those fed from puberty to adulthood. Modifications in the developmental pattern from puberty to adulthood were observed for most of the brain receptors studied. In adult animals fed the fat diet from weaning onwards, the levels of leptin receptors in the hypothalamus and glucocorticoid receptors in the hippocampus were decreased compared to chow-fed controls. Switching from fat to normal chow at puberty onset restored the diet-induced alterations on circulating leptin, but not on its hypothalamic receptors. These data suggest that when a fat-enriched diet, resembling those consumed by many teenagers, provided in rats during pubertal growth, it can longitudinally influence the actions of leptin and corticosterone in the brain. The observed alterations at a preobese state may constitute early signs of the disturbed energy balance toward overweight and obesity.
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Affiliation(s)
- George Boukouvalas
- Laboratory of Histology and Embryology, School of Medicine, University of Athens, Athens, Greece
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13
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Boukouvalas G, Antoniou K, Papalexi E, Kitraki E. Post weaning high fat feeding affects rats' behavior and hypothalamic pituitary adrenal axis at the onset of puberty in a sexually dimorphic manner. Neuroscience 2008; 153:373-82. [DOI: 10.1016/j.neuroscience.2008.02.023] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2007] [Revised: 02/12/2008] [Accepted: 02/19/2008] [Indexed: 11/24/2022]
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14
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Voutsas IF, Gritzapis AD, Alexis MN, Katsanou ES, Perez S, Baxevanis CN, Papamichail M. A novel quantitative flow cytometric method for measuring glucocorticoid receptor (GR) in cell lines: correlation with the biochemical determination of GR. J Immunol Methods 2007; 324:110-9. [PMID: 17582432 DOI: 10.1016/j.jim.2007.05.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2006] [Revised: 04/11/2007] [Accepted: 05/11/2007] [Indexed: 01/01/2023]
Abstract
Currently, a time consuming biochemical method is used for GR quantification. Here we compare the biochemical approach with a newly developed flow cytometric method of measuring GR in cell lines, which is less time consuming and does not requires the use of radioactive materials. The biochemical assay is easy to apply but the cells need to be grown in media free of endogenous glucocorticoids, in order to prevent them from interfering with radiolabelled hormone binding to the receptor. The presence of endogenous GR ligands is known to reduce receptor levels and to often produce false negative results. The immunofluorescent method is free of such limitations, as it depends entirely on detecting the receptor using a highly specific monoclonal antibody. Additionally, the biochemical assay cannot measure heterogeneity in individual cells, in contrast the flow cytometric one enables the enumeration of the receptor on a per cell basis, allowing exact description of differences in receptor levels amongst intact cells. Our results demonstrate that the flow cytometric method is of similar accuracy but of higher precision compared to the biochemical one. Also, the data we obtained using the immunofluorescent method correlated well with the biochemical one (R(2)=0.9712). In conclusion, flow cytometric method requires small cell numbers, is more accurate and lesser time consuming than the biochemical one. Thus, it could be useful for the quantification of GR in lymphocyte subpopulations, in lymphoproliferative disorders and in tumor cells from cancer patients, in order to design more efficient clinical treatment protocols.
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Affiliation(s)
- Ioannis F Voutsas
- Cancer Immunology and Immunotherapy Center, Saint Savvas Cancer Hospital, 171 Alexandras Ave., 11522 Athens, Greece.
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Siriani D, Mitsiou DJ, Alexis MN. Heat-induced degradation of overexpressed glucocorticoid receptor Separate protective roles of hsp90 and hsp70. J Steroid Biochem Mol Biol 2005; 94:93-101. [PMID: 15862954 DOI: 10.1016/j.jsbmb.2005.01.013] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The glucocorticoid receptor (GR) occurs in cells in the form of a hormone-responsive complex (HRC) with hsp90. The HRC is dynamic, with hsp90 constantly directing disassembly, and hsp70, assisted by hsp90, driving reassembly. WCL2 cells stably overexpress GR to an extent that reduces the excess of hsp90 and hsp70 over GR by about 10-fold, compared to the ratio in HeLa cells. Yet the half-lives of the HRC in WCL2 and HeLa cells are comparable. As a result, the rate of assembly in WCL2 is overwhelmed by accumulation of the non-hormone-binding form of GR in its complex with hsp70 and hsp90. This form comprised some 50% of total GR in WCL2 cells. When the cells were heated to 44 degrees C, the hormone-binding activity and solubility of GR fell in parallel, and the receptor formed heavy aggregates by sequestering large amounts of hsp70. About 40% of this aggregated receptor was degraded in cells recovering at 37 degrees C in the presence of cycloheximide. Concentration of GR protein increased with increasing induction of hsp70 following exposure to 41-44 degrees C. However, balance between hormone-binding and inert forms of GR could shift in either direction in response to the increase or decrease of hsp90 induction, depending on the temperature. Suppression of degradation following re-exposure of the cells to 44 degrees C correlated better with induction of hsp90 than hsp70. We infer that sequestration of hsp70 by heat-unfolded receptor is the primary factor opposing degradation, while induction of hsp90 acts to further suppress degradation by accelerating HRC assembly.
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Affiliation(s)
- Despina Siriani
- Molecular Endocrinology Programme, Institute of Biological Research and Biotechnology, The National Hellenic Research Foundation, 48 Vas. Constantinou Ave, 11635 Athens, Greece
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Muller C, Cluzeaud F, Pinon GM, Rafestin-Oblin ME, Morfin R. Dehydroepiandrosterone and its 7-hydroxylated metabolites do not interfere with the transactivation and cellular trafficking of the glucocorticoid receptor. J Steroid Biochem Mol Biol 2004; 92:469-76. [PMID: 15698552 DOI: 10.1016/j.jsbmb.2004.10.014] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2004] [Accepted: 10/08/2004] [Indexed: 11/27/2022]
Abstract
The human brain is a target tissue for glucocorticoids (GC). Dehydroepiandrosterone (DHEA) is a neurosteroid produced in the brain where it is transformed into 7alpha-hydroxy-DHEA and 7beta-hydroxy-DHEA. The antiglucocorticoid effects of both 7-hydroxylated metabolites have been investigated with evidence in mice that neither form of DHEA interfered with the binding of GC to its glucocorticoid receptor (GR), but contributed to a decreased nuclear uptake of the activated GR. Our objective was to use COS-7 cell culture to research DHEA, 7alpha-hydroxy-DHEA and 7beta-hydroxy-DHEA interferences with GR trafficking. These cells did not carry out the 7alpha-hydroxylation of DHEA and the oxidation of cortisol into cortisone. The cDNA of the human GR was inserted into pcDNA3 for a transient transfection of COS-7 cells. Human GR transactivation activity was measured from a luciferase-MMTV reporter gene. The transfected COS-7 cells were cultured using 10(-12) to 10(-5) M dexamethasone (DEX) or cortisol, which triggered the reporter expression. Treatment with 10(-12) to 10(-5) M DHEA, 7alpha-hydroxy-DHEA and 7beta-hydroxy-DHEA caused no change in the GC-induced GR transactivation. A reconstruction of the process associated EGFP to the human GR cDNA. Confocal microscopic examination of COS-7 cells transiently expressing the fusion protein EGFP-GR showed nuclear fluorescence 60 min after incubation with 10(-8) M DEX or cortisol. The addition of 10(-5) M DHEA, 7alpha-hydroxy-DHEA or 7beta-hydroxy-DHEA did not change its kinesis and intensity. These results contribute to the knowledge of DHEA, 7alpha-hydroxy-DHEA and 7beta-hydroxy-DHEA, in relation to antiglucocorticoid activity. We conclude that direct interference with GR trafficking can be discounted in the case of these hormones, therefore proposing new possibilities of investigation.
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Affiliation(s)
- Caroline Muller
- Laboratoire de Biotechnologie, EA-3199, Conservatoire National des Arts et Métiers, 2 rue Conté, 75003 Paris, France
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Kitraki E, Kremmyda O, Youlatos D, Alexis MN, Kittas C. Gender-dependent alterations in corticosteroid receptor status and spatial performance following 21 days of restraint stress. Neuroscience 2004; 125:47-55. [PMID: 15051144 DOI: 10.1016/j.neuroscience.2003.12.024] [Citation(s) in RCA: 132] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2003] [Revised: 12/16/2003] [Accepted: 12/22/2003] [Indexed: 11/17/2022]
Abstract
The effects of 21-day exposure to restraint stress on hippocampal corticosteroid receptors and on spatial performance of male and female rats were evaluated. Stressed male animals exhibited a decrease in glucocorticoid receptor immunoreactivity in the CA1 area and the dentate gyrus. At the same time, stressed males tested on Morris water maze showed delayed learning and worse memory scores, compared with the control males. By contrast, stressed females exhibited an increase in glucocorticoid receptor immunoreactivity in CA1, similar learning ability and improved memory scores, compared with control females. In addition, stressed females showed a significant increase in mineralocorticoid receptor immunoreactivity in the CA3 area compared with controls. These data show that 21 days of restraint stress affect hippocampal corticosteroid receptors and spatial performance in a gender-specific manner. The observed changes in corticosteroid receptor levels following stress, may be causatively linked to the stress-induced alterations on spatial learning and memory.
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Affiliation(s)
- E Kitraki
- Laboratory of Histology and Embryology, Athens University Medical School, Mikras Asias 75, Goudi 11527, Athens, Greece.
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Kitraki E, Kremmyda O, Youlatos D, Alexis M, Kittas C. Spatial Performance and Corticosteroid Receptor Status in the 21-Day Restraint Stress Paradigm. Ann N Y Acad Sci 2004; 1018:323-7. [PMID: 15240385 DOI: 10.1196/annals.1296.039] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Twenty-one days of restraint stress has been shown to affect hippocampal plasticity, neurogenesis, and spatial memory. Hippocampal glucocorticoid receptors (GR) and mineralocorticoid receptors (MR) are the main mediators of stress response and learning/memory processes. We studied the performance of male and female rats on a hippocampal-dependent spatial task after 21 days of restraint in relation to the stress-induced changes of GR and MR status in their hippocampi. Reduced GR immunostaining was detected in the dentate gyrus and CA1 area of stressed male rats. Stressed male rats performed worse than the male control rats on the Morris water maze. In contrast, unaltered (in the dentate gyrus) or increased (in CA1) GR immunoreactivity was seen in the hippocampus of stressed female rats. Stressed female rats had an improved memory score in the task compared with the female control rats. In addition, stressed female rats showed increased MR immunostaining in the CA3 area, which is known to be severely affected by stress. The observed sexually dimorphic effects of 21-day restraint in spatial learning and memory may be associated with the sex-dependent changes in hippocampal corticosteroid receptor status after stress.
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Affiliation(s)
- Efthimia Kitraki
- Laboratory of Histology and Embryology, Athens University Medical School, Mikras Asias 75, 11527 Athens, Greece.
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