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Abstract
The primary adrenal cortical steroid hormones, aldosterone, and the glucocorticoids cortisol and corticosterone, act through the structurally similar mineralocorticoid (MR) and glucocorticoid receptors (GRs). Aldosterone is crucial for fluid, electrolyte, and hemodynamic homeostasis and tissue repair; the significantly more abundant glucocorticoids are indispensable for energy homeostasis, appropriate responses to stress, and limiting inflammation. Steroid receptors initiate gene transcription for proteins that effect their actions as well as rapid non-genomic effects through classical cell signaling pathways. GR and MR are expressed in many tissues types, often in the same cells, where they interact at molecular and functional levels, at times in synergy, others in opposition. Thus the appropriate balance of MR and GR activation is crucial for homeostasis. MR has the same binding affinity for aldosterone, cortisol, and corticosterone. Glucocorticoids activate MR in most tissues at basal levels and GR at stress levels. Inactivation of cortisol and corticosterone by 11β-HSD2 allows aldosterone to activate MR within aldosterone target cells and limits activation of the GR. Under most conditions, 11β-HSD1 acts as a reductase and activates cortisol/corticosterone, amplifying circulating levels. 11β-HSD1 and MR antagonists mitigate inappropriate activation of MR under conditions of oxidative stress that contributes to the pathophysiology of the cardiometabolic syndrome; however, MR antagonists decrease normal MR/GR functional interactions, a particular concern for neurons mediating cognition, memory, and affect.
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Affiliation(s)
- Elise Gomez-Sanchez
- G.V.(Sonny) Montgomery V.A. Medical Center and Department of Medicine, University of Mississippi Medical Center, Jackson, Mississippi
| | - Celso E. Gomez-Sanchez
- G.V.(Sonny) Montgomery V.A. Medical Center and Department of Medicine, University of Mississippi Medical Center, Jackson, Mississippi
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2
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Schmitz B, Nedele J, Guske K, Maase M, Lenders M, Schelleckes M, Kusche-Vihrog K, Brand SM, Brand E. Soluble Adenylyl Cyclase in Vascular Endothelium. Hypertension 2014; 63:753-61. [DOI: 10.1161/hypertensionaha.113.02061] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The Ca
2+
- and bicarbonate-activated soluble adenylyl cyclase (sAC) has been identified recently as an important mediator of aldosterone signaling in the kidney. Nuclear sAC has been reported to stimulate cAMP response element–binding protein 1 phosphorylation via protein kinase A, suggesting an alternative cAMP pathway in the nucleus. In this study, we analyzed the sAC as a potential modulator of endothelial stiffness in the vascular endothelium. We determined the contribution of sAC to cAMP response element–mediated transcriptional activation in vascular endothelial cells and kidney collecting duct cells. Inhibition of sAC by the specific inhibitor KH7 significantly reduced cAMP response element–mediated promoter activity and affected cAMP response element–binding protein 1 phosphorylation. Furthermore, KH7 and anti-sAC small interfering RNA significantly decreased mRNA and protein levels of epithelial sodium channel-α and Na
+
/K
+
-ATPase-α. Using atomic force microscopy, a nano-technique that measures stiffness and deformability of living cells, we detected significant endothelial cell softening after sAC inhibition. Our results suggest that the sAC is a regulator of gene expression involved in aldosterone signaling and an important regulator of endothelial stiffness. Additional studies are warranted to investigate the protective action of sAC inhibitors in humans for potential clinical use.
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Affiliation(s)
- Boris Schmitz
- From Internal Medicine D, Department of Nephrology, Hypertension, and Rheumatology (B.S., J.N., K.G., M.L., M.S., E.B.) and Institute of Sports Medicine, Molecular Genetics of Cardiovascular Disease (B.S., S.-M.B.), University Hospital Muenster, Muenster, Germany; and Institute of Physiology II, University of Muenster, Muenster, Germany (M.M., K.K.-V.)
| | - Johanna Nedele
- From Internal Medicine D, Department of Nephrology, Hypertension, and Rheumatology (B.S., J.N., K.G., M.L., M.S., E.B.) and Institute of Sports Medicine, Molecular Genetics of Cardiovascular Disease (B.S., S.-M.B.), University Hospital Muenster, Muenster, Germany; and Institute of Physiology II, University of Muenster, Muenster, Germany (M.M., K.K.-V.)
| | - Katrin Guske
- From Internal Medicine D, Department of Nephrology, Hypertension, and Rheumatology (B.S., J.N., K.G., M.L., M.S., E.B.) and Institute of Sports Medicine, Molecular Genetics of Cardiovascular Disease (B.S., S.-M.B.), University Hospital Muenster, Muenster, Germany; and Institute of Physiology II, University of Muenster, Muenster, Germany (M.M., K.K.-V.)
| | - Martina Maase
- From Internal Medicine D, Department of Nephrology, Hypertension, and Rheumatology (B.S., J.N., K.G., M.L., M.S., E.B.) and Institute of Sports Medicine, Molecular Genetics of Cardiovascular Disease (B.S., S.-M.B.), University Hospital Muenster, Muenster, Germany; and Institute of Physiology II, University of Muenster, Muenster, Germany (M.M., K.K.-V.)
| | - Malte Lenders
- From Internal Medicine D, Department of Nephrology, Hypertension, and Rheumatology (B.S., J.N., K.G., M.L., M.S., E.B.) and Institute of Sports Medicine, Molecular Genetics of Cardiovascular Disease (B.S., S.-M.B.), University Hospital Muenster, Muenster, Germany; and Institute of Physiology II, University of Muenster, Muenster, Germany (M.M., K.K.-V.)
| | - Michael Schelleckes
- From Internal Medicine D, Department of Nephrology, Hypertension, and Rheumatology (B.S., J.N., K.G., M.L., M.S., E.B.) and Institute of Sports Medicine, Molecular Genetics of Cardiovascular Disease (B.S., S.-M.B.), University Hospital Muenster, Muenster, Germany; and Institute of Physiology II, University of Muenster, Muenster, Germany (M.M., K.K.-V.)
| | - Kristina Kusche-Vihrog
- From Internal Medicine D, Department of Nephrology, Hypertension, and Rheumatology (B.S., J.N., K.G., M.L., M.S., E.B.) and Institute of Sports Medicine, Molecular Genetics of Cardiovascular Disease (B.S., S.-M.B.), University Hospital Muenster, Muenster, Germany; and Institute of Physiology II, University of Muenster, Muenster, Germany (M.M., K.K.-V.)
| | - Stefan-Martin Brand
- From Internal Medicine D, Department of Nephrology, Hypertension, and Rheumatology (B.S., J.N., K.G., M.L., M.S., E.B.) and Institute of Sports Medicine, Molecular Genetics of Cardiovascular Disease (B.S., S.-M.B.), University Hospital Muenster, Muenster, Germany; and Institute of Physiology II, University of Muenster, Muenster, Germany (M.M., K.K.-V.)
| | - Eva Brand
- From Internal Medicine D, Department of Nephrology, Hypertension, and Rheumatology (B.S., J.N., K.G., M.L., M.S., E.B.) and Institute of Sports Medicine, Molecular Genetics of Cardiovascular Disease (B.S., S.-M.B.), University Hospital Muenster, Muenster, Germany; and Institute of Physiology II, University of Muenster, Muenster, Germany (M.M., K.K.-V.)
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3
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Stanisić V, Lonard DM, O'Malley BW. Modulation of steroid hormone receptor activity. PROGRESS IN BRAIN RESEARCH 2010; 181:153-76. [PMID: 20478437 DOI: 10.1016/s0079-6123(08)81009-6] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Classical steroid hormones (SHs) - estrogens, androgens, progestins, glucocorticoids and mineralocorticoids - play critical roles in the regulation of reproduction, metabolism and cancer. SHs act via their cognate steroid hormone receptors (SHRs) in multiple target tissues throughout the body, exerting their physiological effects through nuclear receptor (NR)-mediated gene transcription. Since SHRs are the mediators of steroid hormone signalling in cells, regulation of their expression and function is critical for appropriate physiological responses to SHs. Cells regulate SHRs by determining the cellular concentration of SHR proteins in the cell and by tightly regulating their activity through post-translational modifications and interactions with coactivator protein complexes. In this chapter we will examine each of these regulatory mechanisms and assess their functional impact on the activity of SHRs.
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Affiliation(s)
- Vladimir Stanisić
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Texas, United States of America
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4
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Corticosteroid receptor-gene variants: modulators of the stress-response and implications for mental health. Eur J Pharmacol 2008; 585:492-501. [PMID: 18423443 DOI: 10.1016/j.ejphar.2008.03.012] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2007] [Revised: 02/22/2008] [Accepted: 03/03/2008] [Indexed: 11/24/2022]
Abstract
The stress-response, including autonomic and hypothalamic-pituitary-adrenal (HPA) axis reactivity, is essential for maintaining homeostasis during a challenge. Brain mineralocorticoid receptors and glucocorticoid receptors operate in balance to coordinate the stress-response. Genetic variants in both the human mineralocorticoid and glucocorticoid receptor-genes have been functionally characterized. In vitro effects of these genetic variants on transactivation and mRNA stability have been described. In vivo, two mineralocorticoid receptor-gene SNPs (-2 G/C (allele frequency: 50%), MR I180V (11%)) and four glucocorticoid receptor-gene SNPs (ER22/23EK (3%), N363S (4%), BclI (37%), A3669G (15%)) are associated with changes in hypothalamic-pituitary-adrenal (HPA) axis reactivity. Importantly, the two mineralocorticoid receptor-gene variants (but none of the glucocorticoid receptor-gene variants) also associate with changes in autonomic output as measured as increased heart beat following a psychosocial stress (TSST). Moreover, several of these mineralocorticorticoid receptor- and glucocorticoid receptor variants have been found associated with stress-related disorders, including depression. These data indicate that dysregulation of mineralocorticoid- and glucocorticoid receptor are causative in the pathogenesis of depression. Moreover, these mineralocorticoid- and glucocorticoid receptor-gene variants constitute part of the genetic make up that determines individual stress-responsiveness inducing vulnerability to disease. Furthermore, mineralocorticoid- and glucocorticoid receptors are drug targets, thereby aiming at the underlying mechanisms of stress-related disorders.
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Derijk RH, de Kloet ER. Corticosteroid receptor polymorphisms: determinants of vulnerability and resilience. Eur J Pharmacol 2008; 583:303-11. [PMID: 18321483 DOI: 10.1016/j.ejphar.2007.11.072] [Citation(s) in RCA: 134] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2007] [Revised: 10/03/2007] [Accepted: 11/14/2007] [Indexed: 11/29/2022]
Abstract
Why some individuals thrive and others break down under similar adverse conditions, is a central question in the neuroendocrinology of stress related psychopathology. The brain mineralocorticoid (MR) and glucocorticoid receptors (GR) operate in balance to coordinate behavioural, autonomic and neuroendocrine response patterns involved in homeostasis and health. Genetic variants of both the MR and GR have been functionally characterized. The four GR-gene single nucleotide polymorphisms (SNPs) (ER22/23EK (allele frequency: 3%), N363S (4%), BclI (37%), A3669G (15%)) and the two MR-gene SNPs (-2 G/C (50%), MR-I180V (11%)) showed in vitro changes in transactivational capacity, or affect stability of the mRNA (GR exon 9beta A3669G). All of these MR-and GR-SNPs change the regulation of the hypothalamus-pituitary-adrenal (HPA) axis at different levels including basal level (-2 G/C), dexamethasone induced negative feedback (ER22/23EK, N363S, BclI, 9beta A3669G) or following a psychosocial stress test (Trier Social Stress Test (TSST); all of the MR-and GR-SNPs). Importantly, the MR-I180V increased autonomic output and enhanced cortisol secretion during the TSST. Recently, several of these MR-and GR-variants have been found associated with psychopathology (depression, bipolar disorder). These data provide evidence that dysregulation of MR and GR are causative in the pathogenesis of depression and that these MR-and GR-gene variants are part of the genetic make up that determines individual stress-responsivity and coping style, affecting vulnerability to disease.
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Affiliation(s)
- Roel H Derijk
- Division of Medical Pharmacology, Leiden/Amsterdam Center for Drug Research, Leiden University Medical Center, Leiden University, PO Box 9502, 2300 RA Leiden, The Netherlands.
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Smith C, Wilson NW, Louw A, Myburgh KH. Illuminating the interrelated immune and endocrine adaptations after multiple exposures to short immobilization stress by in vivo blocking of IL-6. Am J Physiol Regul Integr Comp Physiol 2007; 292:R1439-47. [PMID: 17170234 DOI: 10.1152/ajpregu.00602.2006] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Intermittent psychological stress was induced in adult rats by 2 h/day of immobilization stress for 4 days, with or without blocking the function of IL-6 by using an anti-IL-6 antibody. Basal concentrations of serum corticosterone, IL-1β, IL-6, and TNF-α were assessed 24 h after the last intervention, as were levels of glucocorticoid receptors (GR) and activities of glucocorticoid-inducible enzymes (tyrosine aminotransferase and glutamine synthetase) in muscle and liver. Whole blood cultures were used to assess both spontaneous and LPS-induced reactivity of peripheral blood mononuclear cells. Stress increased corticosterone concentration in a manner partially modulated by IL-6. Serum IL-1β concentration was downregulated during stress when IL-6 was blocked ( P < 0.01). LPS-induced IL-6 secretion by peripheral blood mononuclear cells in vitro correlated positively with serum IL-1β concentration in antibody-treated groups, independently of stress ( R = 0.70 in nonstressed and R = 0.78 in stressed rats; both P < 0.05), whereas serum corticosterone concentration correlated positively with LPS-induced secretion of IL-6 only in control rats ( R = 0.66; P < 0.05). Reductions in liver GR levels indicated independent effects of stress (34.5%) and anti-IL-6 antibody (16.7%) and additive effects for both (62.5%). Similar results are reported for vastus muscle. Conversely, stress increased tyrosine aminotransferase and glutamine synthetase activities in muscle and liver with a significant ( P < 0.05) effect of anti-IL-6 antibody only seen in stressed livers. In conclusion, IL-6 plays a role in maintaining circulating IL-1β concentration after multiple exposures to stress, thus promoting a continued elevation of corticosterone release; in peripheral tissues, IL-6 antagonizes the effects of glucocorticoids, especially at the level of GR concentration.
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Affiliation(s)
- C Smith
- Department of Physiological Sciences, University of Stellenbosch, Private Bag X1, Matieland 7602, South Africa.
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7
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Mandl M, Ghaffari-Tabrizi N, Haas J, Nöhammer G, Desoye G. Differential glucocorticoid effects on proliferation and invasion of human trophoblast cell lines. Reproduction 2006; 132:159-67. [PMID: 16816341 DOI: 10.1530/rep.1.00976] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Several clinical situations require continuous glucocorticoid (GC) treatment during pregnancy. A well-known deleterious side effect of such treatment is the higher incidence of growth-restricted fetuses, for which a too shallow trophoblast invasion is presently hypothesised as the underlying cause. This study investigated whether the synthetic GC triamcinolone acetonide (TA) influences proliferation, invasion and endocrine activity of human trophoblast. BeWo and JEG-3 choriocarcinoma cell lines both express GC receptors (western blotting) and were used as models for human trophoblast. JAR devoid cells of GC receptor were used as negative control. The cells were cultured for 48 h without (control) or with 0.5, 5 and 50 microM TA. In the presence and absence of serum, proliferation was determined by cell counting and measuring the cell cycle regulating protein cyclin B1 (Western blotting); invasion was determined by a conventional Matrigel invasion assay and by measuring the secretion (ELISA) of matrix-metalloproteinases (MMP-2, MMP-9) into the culture medium; endocrine activity was assessed by measuring the levels of human chorionic gonadotropin (ELISA) into the culture medium. TA altered the number of viable and dead cells as well as cyclin B1 levels and, to a lesser extent, invasion of BeWo and JEG-3, with a strong influence of serum. BeWo and JEG-3 cells reacted differently and in most instances reverse. In the cell lines used as models of human trophoblast, TA alter some functions relevant to proliferation and invasion, and suggest that caution should be exercised when treating women with GCs during pregnancy.
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Affiliation(s)
- M Mandl
- Clinic of Obstetrics and Gynaecology, Medical-University of Graz, Auenbruggerplatz 14, A-8036, Graz, Austria
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DeRijk R, de Kloet ER. Corticosteroid receptor genetic polymorphisms and stress responsivity. Endocrine 2005; 28:263-70. [PMID: 16388115 DOI: 10.1385/endo:28:3:263] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2005] [Accepted: 07/13/2005] [Indexed: 11/11/2022]
Abstract
A fundamental question in the neuroendocrinology of stress-related psychopathology is why some individuals flourish and others perish under similar adverse conditions. In this contribution we focus on the variants of mineralocorticorticoid (MR) and glucocorticoid receptors (GR) that operate in balance and coordinate behavioral, autonomic, and neuroendocrine response patterns involved in homeostasis and health. In the GR-gene, three single nucleotide polymorphism (SNPs) have been associated with changes in metabolic profile and cardiovascular parameters: the ER22/23EK with a favorable and the N363S and the Bcl1 with a more adverse profile. Importantly, the N363S and the Bcl1 are found to increase cortisol responses to a psychosocial stressor. As a result, the whole body will suffer from overexposure with possible adverse effects on metabolism, cardiovascular control, immune function, and behavior. Also in the MR gene, variants are being identified that are associated with dysregulated autonomic, behavioral, and neuroendocrine responses. The data suggest that these MR and GR variants contribute to individual differences in resilience and vulnerability to stressors, and that these receptors therefore are potential drug targets for recovery of homeostasis and health.
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MESH Headings
- Adaptation, Physiological
- Humans
- Hydrocortisone/metabolism
- Polymorphism, Single Nucleotide/genetics
- Receptors, Glucocorticoid/genetics
- Receptors, Glucocorticoid/metabolism
- Receptors, Mineralocorticoid/genetics
- Receptors, Mineralocorticoid/metabolism
- Stress, Physiological/genetics
- Stress, Physiological/metabolism
- Stress, Psychological/genetics
- Stress, Psychological/metabolism
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Affiliation(s)
- Roel DeRijk
- Department of Psychiatry, Leiden University Medical Center, 2300 RC, Leiden, The Netherlands
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9
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Mohaupt MG, Frey FJ. Mineralocorticoid receptor malfunction: further insights from rare forms of hypertension. Nephrol Dial Transplant 2002; 17:539-42. [PMID: 11917040 DOI: 10.1093/ndt/17.4.539] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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10
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Abstract
The members of the nuclear receptor superfamily are known to mediate a wide array of basic biological processes, such as regulation of cell growth and differentiation, and induction of apoptosis. In several human malignancies, this central control function of nuclear receptors is disturbed, which seems to play an important role in tumor development and progression. Many nuclear receptor genes have been reported to be downregulated in malignancies; however, only a few mutations, gene arrangements, deletions or similar genetic changes have been shown to occur in these tumors. During the last decade, increasing attention has been directed towards epigenetic mechanisms of gene regulation such as DNA methylation. Many nuclear receptor genes can be silenced through aberrant methylation in tumors; epigenetic silencing, therefore, represents an additional mechanism that modifies expression of key genes during carcinogenesis. This review will give insights into the role of DNA methylation in the silencing of nuclear receptor genes and its involvement in human malignancies.
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Affiliation(s)
- J Berger
- Department of Obstetrics and Gynecology, University Hospital, 6020 Innsbruck, Austria
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11
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Cain BM, Vishnuvardhan D, Beinfeld MC. Neuronal cell lines expressing PC5, but not PC1 or PC2, process Pro-CCK into glycine-extended CCK 12 and 22. Peptides 2001; 22:1271-7. [PMID: 11457520 DOI: 10.1016/s0196-9781(01)00451-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Endocrine tumor cells in culture and in vitro cleavage assays have shown that PC1 and PC2 are capable of processing pro-CCK into smaller, intermediate and final, bioactive forms. Similar studies have shown that PC5 has the ability to process a number of propeptides. Here, we use GT1-7 (mouse hypothalamic) and SK-N-MC and SK-N-SH (human neuroblastoma) tumor cell lines to study the ability of PC5 to process pro-CCK. RT-PCR and Western blot analysis showed that the cells express PC5 mRNA and protein, but not PC1 or PC2. They were engineered to stably overexpress CCK and cell media was analyzed for pro-CCK expression and cleavage of the prohormone. Radioimmunoassays showed that pro-CCK was expressed, but no amidated CCK was detected. Lack of production of amidated CCK may be due to the lack of the appropriate carboxypeptidase and amidating enzymes. Production of glycine-extended CCK processing products was evaluated by treatment of media with carboxypeptidase B followed by analysis with a CCK Gly RIA. Glycine-extended forms of the peptide were found in the media. The predominant forms co-eluted with CCK 12 Gly and CCK 22 Gly on gel filtration chromatography. The results demonstrate that these cell lines which express PC5 and not PC1 or PC2 have the ability to process pro-CCK into intermediate, glycine-extended forms more closely resembling pro-CCK products in intestine than in brain.
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Affiliation(s)
- B M Cain
- Department of Pharmacology and Experimental Therapeutics, Tufts University School of Medicine, Boston, MA 02111, USA.
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12
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Piwien-Pilipuk G, Galigniana MD. Tautomycin inhibits phosphatase-dependent transformation of the rat kidney mineralocorticoid receptor. Mol Cell Endocrinol 1998; 144:119-30. [PMID: 9863632 DOI: 10.1016/s0303-7207(98)00142-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
The binding of aldosterone (ALDO) to the mineralocorticoid receptor (MR) induces a conformational change of the protein referred to as 'transformation'. This feature can be evidenced in vivo by the capacity of the MR to interact with chromatin, and in vitro by the ability of the MR to bind to DNA strands or to shift the sedimentation coefficient (S) to lower values. The transformation process allows MR to work as a transcription factor after interacting with specific sequences of DNA. The signal transduction pathway for the MR transformation remains unknown. As a first step towards elucidating the mechanism of steroid-dependent MR transformation, we asked if the MR-signaling pathway is affected by the phosphorylation status of the MR-heterocomplex, and how that pathway may be regulated. Incubation of preformed [3H]ALDO-MR complex with bovine intestinal alkaline phosphatase led to an increase in the rate of MR-transformation (measured as 9.4-5.4S shift). This alkaline phosphatase-dependent MR transformation was inhibited by the specific alkaline phosphatase-type inhibitor levamisole, and was not evident in incubations performed with acid phosphatases. A direct correlation between the DNA-cellulose binding capacity of the [3H]ALDO-MR complex and the percentage of transformed 5.4S MR form was also observed. When rat kidney cytosol was incubated in the absence of both exogenous phosphatase and stabilizing agents (such as molybdate or vanadate), MR transformation also took place, in a time- and temperature-dependent process. In contrast with the inhibitory effect observed upon alkaline phosphatase-promoted transformation, levamisole was unable to inhibit the endogenous transforming activity of MR, suggesting that an endogenous phosphatase other than those which belong to the alkaline-type may be responsible for that transformation. Tautomycin, a polyketide produced by the soil bacteria Streptomyces which inhibits serine/threonine phosphatases of the PP1/PP2A subgroup, was able to inhibit the endogenous phosphatase activity in a concentration-dependent form (Ki(app)=7.35 nM). These results support the idea that the endogenous renal activity involved in the regulation of rat kidney MR transformation may be a protein phosphatase which belongs to the PP1/PP2A subgroup.
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Affiliation(s)
- G Piwien-Pilipuk
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires and PRHOM-CONICET, Argentina
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Vázquez DM, López JF, Morano MI, Kwak SP, Watson SJ, Akil H. Alpha, beta, and gamma mineralocorticoid receptor messenger ribonucleic acid splice variants: differential expression and rapid regulation in the developing hippocampus. Endocrinology 1998; 139:3165-77. [PMID: 9645690 DOI: 10.1210/endo.139.7.6095] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Two different types of corticoid receptor molecules bind circulating corticosterone in brain: mineralocorticoid receptors (MR) and glucocorticoid receptors. MR exhibit the highest affinity for the endogenous glucocorticoid in the rat, corticosterone. During development, low corticosterone levels influence neurogenesis, and these effects are probably MR mediated. Three MR complementary DNA clones, alpha, beta, and gamma, have been identified in the rodent. All of these MR complementary DNA clones have identical coding regions, but differ significantly at the 5'-untranslated end. Although the functional significance of these three messenger RNA (mRNA) species remains unknown, one hypothesis is that they reflect the ability of the brain to regulate the expression of MR, allowing multiple factors to differentially control transcription in a tissue- and time-specific manner. To investigate this possibility, we examined the presence of these distinct mRNA forms in the developing rat hippocampus (HC). In situ hybridization with specific alpha, beta, and gamma complementary RNA probes was performed in the HC of 3-, 5-, 7-, 12-, 14-, 28-, 35-, and 65-day-old animals. We found that there is differential expression of these forms in each of the HC subfields from infancy to adulthood. y expression appears to be associated with periods of cell birth and increased axonal sprouting. beta expression, on the other hand, may be best linked to periods of synaptogenesis, growth of commissural and associative terminal fields, and possibly active pruning. To explore the possibility that the differential gene expression may be related to corticosterone environment, adrenalectomy was performed. A rapid modulation of the MR mRNA variants (14 h) in an age- and site-specific fashion was seen. These findings suggest that the variation in expression and regulation during development of the multiple MR transcripts could reflect a complex pattern of developmental regulation that may involve a multitude of factors unique to each postnatal age and to the different neuronal populations within the hippocampal formation.
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Affiliation(s)
- D M Vázquez
- Department of Pediatrics, Mental Health Research Institute, University of Michigan, Ann Arbor 48109, USA
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