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Spaulding SC, Bollag WB. The role of lipid second messengers in aldosterone synthesis and secretion. J Lipid Res 2022; 63:100191. [PMID: 35278411 PMCID: PMC9020094 DOI: 10.1016/j.jlr.2022.100191] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Revised: 02/24/2022] [Accepted: 02/25/2022] [Indexed: 11/23/2022] Open
Abstract
Second messengers are small rapidly diffusing molecules or ions that relay signals between receptors and effector proteins to produce a physiological effect. Lipid messengers constitute one of the four major classes of second messengers. The hydrolysis of two main classes of lipids, glycerophospholipids and sphingolipids, generate parallel profiles of lipid second messengers: phosphatidic acid (PA), diacylglycerol (DAG), and lysophosphatidic acid versus ceramide, ceramide-1-phosphate, sphingosine, and sphingosine-1-phosphate, respectively. In this review, we examine the mechanisms by which these lipid second messengers modulate aldosterone production at multiple levels. Aldosterone is a mineralocorticoid hormone responsible for maintaining fluid volume, electrolyte balance, and blood pressure homeostasis. Primary aldosteronism is a frequent endocrine cause of secondary hypertension. A thorough understanding of the signaling events regulating aldosterone biosynthesis may lead to the identification of novel therapeutic targets. The cumulative evidence in this literature emphasizes the critical roles of PA, DAG, and sphingolipid metabolites in aldosterone synthesis and secretion. However, it also highlights the gaps in our knowledge, such as the preference for phospholipase D-generated PA or DAG, as well as the need for further investigation to elucidate the precise mechanisms by which these lipid second messengers regulate optimal aldosterone production.
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Affiliation(s)
- Shinjini C Spaulding
- Department of Physiology, Medical College of Georgia at Augusta University, Augusta, GA, USA
| | - Wendy B Bollag
- Department of Physiology, Medical College of Georgia at Augusta University, Augusta, GA, USA; Research Department, Charlie Norwood VA Medical Center, Augusta, GA, USA.
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Ajdžanović V, Miler M, Živanović J, Filipović B, Šošić-Jurjević B, Popovska-Perčinić F, Milošević V. The adrenal cortex after estradiol or daidzein application in a rat model of the andropause: Structural and hormonal study. Ann Anat 2020; 230:151487. [PMID: 32120001 DOI: 10.1016/j.aanat.2020.151487] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Revised: 02/03/2020] [Accepted: 02/11/2020] [Indexed: 12/31/2022]
Abstract
INTRODUCTION AND AIM Daidzein application may represent an effective and less harmful alternative to indicated, classical estrogenization of ageing men. The aim of this study was to perform structural and hormonal analysis of the adrenal cortex, after estradiol or daidzein supplementation in a rat model of the andropause. MATERIAL AND METHODS Middle-aged Wistar rats were divided into sham operated (SO; n = 8), orchidectomized (Orx; n = 8), estradiol treated orchidectomized (Orx + E; n = 8) and daidzein treated orchidectomized (Orx + D; n = 8) groups. Estradiol (0.625 mg/kg b.m./day) or daidzein (30 mg/kg b.m./day) were administered subcutaneously for three weeks, while the SO and Orx groups received the vehicle alone. Set objectives were achieved using stereology, histochemistry/immunohistochemistry, immunoassays and ultrastructural analysis. RESULTS Both estradiol and daidzein treatment significantly increased volumes of the zona glomerulosa cell and nuclei, but decreased circulating aldosterone levels. Estradiol markedly increased volumes of the zona fasciculata cell and nuclei in parallel with significant decrease of the adrenal tissue level of corticosterone, while daidzein significantly decreased both the adrenal and circulating levels of corticosterone. Serum DHEA level and volumes of the zona reticularis cell and nuclei significantly increased upon estradiol treatment, whereas daidzein even stronger increased the circulating level of DHEA. Shunting of the corticosteroidogenesis pathways towards adrenal androgens production, after the treatments, corresponded to the ultrastructural findings and zonal capillary network rearrangements. CONCLUSIONS Given the coherence of its effects and relative safety, daidzein could be the remedy of choice for the treatment of ageing-caused androgen deprivation and the hypothalamo-pituitary-adrenal axis hyperfunction/related metabolic issues in males.
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Affiliation(s)
- Vladimir Ajdžanović
- Department of Cytology, Institute for Biological Research "Siniša Stanković" - National Institute of Republic of Serbia, University of Belgrade, Belgrade, Serbia.
| | - Marko Miler
- Department of Cytology, Institute for Biological Research "Siniša Stanković" - National Institute of Republic of Serbia, University of Belgrade, Belgrade, Serbia
| | - Jasmina Živanović
- Department of Cytology, Institute for Biological Research "Siniša Stanković" - National Institute of Republic of Serbia, University of Belgrade, Belgrade, Serbia
| | - Branko Filipović
- Department of Cytology, Institute for Biological Research "Siniša Stanković" - National Institute of Republic of Serbia, University of Belgrade, Belgrade, Serbia
| | - Branka Šošić-Jurjević
- Department of Cytology, Institute for Biological Research "Siniša Stanković" - National Institute of Republic of Serbia, University of Belgrade, Belgrade, Serbia
| | | | - Verica Milošević
- Department of Cytology, Institute for Biological Research "Siniša Stanković" - National Institute of Republic of Serbia, University of Belgrade, Belgrade, Serbia
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Luteolin modulates gene expression related to steroidogenesis, apoptosis, and stress response in rat LC540 tumor Leydig cells. Cell Biol Toxicol 2019; 36:31-49. [DOI: 10.1007/s10565-019-09481-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Accepted: 05/27/2019] [Indexed: 01/09/2023]
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Živanović J, Jarić I, Ajdžanović V, Mojić M, Miler M, Šošić-Jurjević B, Milošević V, Filipović B. Daidzein upregulates anti-aging protein Klotho and NaPi 2a cotransporter in a rat model of the andropause. Ann Anat 2018; 221:27-37. [PMID: 30240906 DOI: 10.1016/j.aanat.2018.08.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2018] [Revised: 08/21/2018] [Accepted: 08/30/2018] [Indexed: 11/25/2022]
Abstract
In a rat model of the andropause we aimed to examine the influence of daidzein, soy isoflavone, on the structure and function of parathyroid glands (PTG) and the expression levels of some of the crucial regulators of Ca2+ and Pi homeostasis in the kidney, and to compare these effects with the effects of estradiol, serving as a positive control. Middle-aged (16-month-old) male Wistar rats were divided into the following groups: sham-operated (SO), orchidectomized (Orx), orchidectomized and estradiol-treated (Orx+E; 0.625mg/kg b.w./day, s.c.) as well as orchidectomized and daidzein-treated (Orx+D; 30mg/kg b.w./day, s.c.) group. Every treated group had a corresponding control group. PTH serum concentration was decreased in Orx+E and Orx+D groups by 10% and 21% (p<0.05) respectively, in comparison with the Orx. PTG volume was decreased in Orx+E group by 16% (p<0.05), when compared to the Orx. In Orx+E group expression of NaPi 2a was lower (p<0.05), while NaPi 2a abundance in Orx+D animals was increased (p<0.05), when compared to Orx. Expression of PTH1R was increased (p<0.05) in Orx+E group, while in Orx+D animals the same parameter was decreased (p<0.05), in comparison with Orx. Klotho expression was elevated (p<0.05) in Orx+D rats, in regard to Orx. Orx+D induced reduction in Ca2+/creatinine and Pi/creatinine ratio in urine by 32% and 16% (p<0.05) respectively, in comparison with Orx. In conclusion, presented results indicate the more coherent beneficial effects of daidzein compared to estradiol, on disturbed Ca2+ and Pi homeostasis, and presumably on bone health, in the aging male rats.
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Affiliation(s)
- Jasmina Živanović
- Department of Cytology, Institute for Biological Research "Siniša Stanković", University of Belgrade, Belgrade, Serbia.
| | - Ivana Jarić
- Department of Cytology, Institute for Biological Research "Siniša Stanković", University of Belgrade, Belgrade, Serbia
| | - Vladimir Ajdžanović
- Department of Cytology, Institute for Biological Research "Siniša Stanković", University of Belgrade, Belgrade, Serbia
| | - Marija Mojić
- Department of Immunology, Institute for Biological Research "Siniša Stanković", University of Belgrade, Belgrade, Serbia
| | - Marko Miler
- Department of Cytology, Institute for Biological Research "Siniša Stanković", University of Belgrade, Belgrade, Serbia
| | - Branka Šošić-Jurjević
- Department of Cytology, Institute for Biological Research "Siniša Stanković", University of Belgrade, Belgrade, Serbia
| | - Verica Milošević
- Department of Cytology, Institute for Biological Research "Siniša Stanković", University of Belgrade, Belgrade, Serbia
| | - Branko Filipović
- Department of Cytology, Institute for Biological Research "Siniša Stanković", University of Belgrade, Belgrade, Serbia
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Kim SM, Kang JO, Lim JE, Hwang SY, Oh B. Csk Regulates Blood Pressure by Controlling the Synthetic Pathways of Aldosterone. Circ J 2017; 82:168-175. [PMID: 28724838 DOI: 10.1253/circj.cj-17-0080] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
BACKGROUND Blood pressure is regulated by a network of diverse physiological pathways. The C-terminal Src kinase (CSK) locus (15q24) is associated with blood pressure in various ethnic groups. It was recently reported thatCskinsufficiency increases blood pressure through Src. The mechanisms of hypertension inCsk+/-mice are examined further in this study.Methods and Results:To identify a causal component responsible for hypertension inCsk+/-, the heart rate was measured by electrocardiogram and plasma volume by Evans blue dilution. Plasma volume increased inCsk+/-compared with wild-types, while the heart rate did not change. Plasma sodium and aldosterone levels rose consistently inCsk+/-vs. wild-types, and spironolactone, a mineralocorticoid receptor antagonist, reduced blood pressure. The amounts of Sgk1 and Na+/K+-ATPase (NKA) increased in the kidney ofCsk+/-compared with wild-types. It was also found that Cyp11b2 (aldosterone synthase) was upregulated in the adrenal glands ofCsk+/-, and that Csk was enriched in the zona glomerulosa of adrenals, the major site of aldosterone production in the normal mouse. CONCLUSIONS The results of the present study identify a physiological pathway by which blood pressure is regulated, in which the insufficiency ofCskinduces aldosterone production with zonal specificity in the adrenal glands, increasing sodium reabsorption and plasma volume and thus resulting in hypertension.
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Affiliation(s)
- Sung-Moon Kim
- Department of Animal Biotechnology, Graduate School of Future Convergence Technology, Hankyong National University
| | - Ji-One Kang
- Department of Biochemistry and Molecular Biology, School of Medicine, Kyung Hee University
| | - Ji Eun Lim
- Department of Biochemistry and Molecular Biology, School of Medicine, Kyung Hee University
| | - Sue-Yun Hwang
- Department of Chemical Engineering, College of Engineering, Hankyong National University
| | - Bermseok Oh
- Department of Biochemistry and Molecular Biology, School of Medicine, Kyung Hee University
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Abdel-Khalik J, Björklund E, Nielsen FK, Hansen M. Incorporation of 14C-cholesterol in human adrenal corticocarcinoma H295R cell line and online-radiodetection of produced 14C-steroid hormone metabolites. J Pharm Biomed Anal 2017; 145:569-575. [PMID: 28777968 DOI: 10.1016/j.jpba.2017.06.058] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Accepted: 06/26/2017] [Indexed: 12/28/2022]
Abstract
This study demonstrates the addition of 14C-cholesterol to the human cell line H295R will in-situ form radiolabeled steroid hormones allowing for new mechanistic and metabolic insights. The aim of the present study was to in-situ radiolabel steroid hormones from cell line-incorporated 14C-cholesterol using the OECD guideline 456, H295R steroidogenesis in-vitro assay. Radiodetection of the steroid metabolites of the steroidogenic pathway allows for an improved understanding of the various enzymatic mechanisms involved without necessarily being dependent on quantification. Generated radiolabeled steroids were analyzed using HPLC hyphenated with a Flow Scintillation Analyzer (FSA). H295R cells were incubated with radiolabeled cholesterol and cell media were collected and prepared by solid phase extraction and analyzed with HPLC-FSA. For successful radiolabeling of the steroids in the steroidogenesis of H295R cells, radioactive cholesterol may potentially only need to be added just before the cells are incubated for 72h in well plates. Based on the obtained HPLC-FSA chromatograms, and confirmation of the observations by studies in the literature, a qualitative time profile for the production of steroid hormones was estimated. Multiple radiolabeled steroid hormones were identified by means of analytical standards and UV (ultraviolet) co-chromatography, though the elucidation of multiple metabolites remains unresolved. Although online radiodetection proved to suffer from suboptimal sensitivity, the concept of radiolabeling the steroidogenesis in H295R cells with 14C-cholesterol and detecting the radiolabeled steroid hormones online was proved and may assist in further toxicological studies.
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Affiliation(s)
- Jonas Abdel-Khalik
- Toxicology Laboratory, Analytical Biosciences, Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark.
| | - Erland Björklund
- Toxicology Laboratory, Analytical Biosciences, Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
| | - Frederik Knud Nielsen
- Toxicology Laboratory, Analytical Biosciences, Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
| | - Martin Hansen
- Toxicology Laboratory, Analytical Biosciences, Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark.
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Bandulik S. Of channels and pumps: different ways to boost the aldosterone? Acta Physiol (Oxf) 2017; 220:332-360. [PMID: 27862984 DOI: 10.1111/apha.12832] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Revised: 08/10/2016] [Accepted: 11/11/2016] [Indexed: 01/19/2023]
Abstract
The mineralocorticoid aldosterone is a major factor controlling the salt and water balance and thereby also the arterial blood pressure. Accordingly, primary aldosteronism (PA) characterized by an inappropriately high aldosterone secretion is the most common form of secondary hypertension. The physiological stimulation of aldosterone synthesis in adrenocortical glomerulosa cells by angiotensin II and an increased plasma K+ concentration depends on a membrane depolarization and an increase in the cytosolic Ca2+ activity. Recurrent gain-of-function mutations of ion channels and transporters have been identified in a majority of cases of aldosterone-producing adenomas and in familial forms of PA. In this review, the physiological role of these genes in the regulation of aldosterone synthesis and the altered function of the mutant proteins as well are described. The specific changes of the membrane potential and the cellular ion homoeostasis in adrenal cells expressing the different mutants are compared, and their impact on autonomous aldosterone production and proliferation is discussed.
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Affiliation(s)
- S. Bandulik
- Medical Cell Biology; University of Regensburg; Regensburg Germany
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8
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Steroid profiling in H295R cells to identify chemicals potentially disrupting the production of adrenal steroids. Toxicology 2017; 381:51-63. [DOI: 10.1016/j.tox.2017.02.010] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Revised: 02/09/2017] [Accepted: 02/16/2017] [Indexed: 12/16/2022]
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9
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Abstract
Phospholipases are lipid-metabolizing enzymes that hydrolyze phospholipids. In some cases, their activity results in remodeling of lipids and/or allows the synthesis of other lipids. In other cases, however, and of interest to the topic of adrenal steroidogenesis, phospholipases produce second messengers that modify the function of a cell. In this review, the enzymatic reactions, products, and effectors of three phospholipases, phospholipase C, phospholipase D, and phospholipase A2, are discussed. Although much data have been obtained concerning the role of phospholipases C and D in regulating adrenal steroid hormone production, there are still many gaps in our knowledge. Furthermore, little is known about the involvement of phospholipase A2, perhaps, in part, because this enzyme comprises a large family of related enzymes that are differentially regulated and with different functions. This review presents the evidence supporting the role of each of these phospholipases in steroidogenesis in the adrenal cortex.
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Affiliation(s)
- Wendy B Bollag
- Charlie Norwood VA Medical CenterOne Freedom Way, Augusta, GA, USA Department of PhysiologyMedical College of Georgia, Augusta University (formerly Georgia Regents University), Augusta, GA, USA
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10
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Stindl J, Tauber P, Sterner C, Tegtmeier I, Warth R, Bandulik S. Pathogenesis of Adrenal Aldosterone-Producing Adenomas Carrying Mutations of the Na(+)/K(+)-ATPase. Endocrinology 2015; 156:4582-91. [PMID: 26418325 DOI: 10.1210/en.2015-1466] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Aldosterone-producing adenoma (APA) is a major cause of primary aldosteronism, leading to secondary hypertension. Somatic mutations in the gene for the α1 subunit of the Na(+)/K(+)-ATPase were found in about 6% of APAs. APA-related α1 subunit of the Na(+)/K(+)-ATPase mutations lead to a loss of the pump function of the Na(+)/K(+)-ATPase, which is believed to result in membrane depolarization and Ca(2+)-dependent stimulation of aldosterone synthesis in adrenal cells. In addition, H(+) and Na(+) leak currents via the mutant Na(+)/K(+)-ATPase were suggested to contribute to the phenotype. The aim of this study was to investigate the cellular pathophysiology of adenoma-associated Na(+)/K(+)-ATPase mutants (L104R, V332G, G99R) in adrenocortical NCI-H295R cells. The expression of these Na(+)/K(+)-ATPase mutants depolarized adrenal cells and stimulated aldosterone secretion. However, an increase of basal cytosolic Ca(2+) levels in Na(+)/K(+)-ATPase mutant cells was not detectable, and stimulation with high extracellular K(+) hardly increased Ca(2+) levels in cells expressing L104R and V332G mutant Na(+)/K(+)-ATPase. Cytosolic pH measurements revealed an acidification of L104R and V332G mutant cells, despite an increased activity of the Na(+)/H(+) exchanger. The possible contribution of cellular acidification to the hypersecretion of aldosterone was supported by the observation that aldosterone secretion of normal adrenocortical cells was stimulated by acetate-induced acidification. Taken together, mutations of the Na(+)/K(+)-ATPase depolarize adrenocortical cells, disturb the K(+) sensitivity, and lower intracellular pH but, surprisingly, do not induce an overt increase of intracellular Ca(2+). Probably, the autonomous aldosterone secretion is caused by the concerted action of several pathological signaling pathways and incomplete cellular compensation.
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Affiliation(s)
- J Stindl
- Medical Cell Biology, University of Regensburg, 93053 Regensburg, Germany
| | - P Tauber
- Medical Cell Biology, University of Regensburg, 93053 Regensburg, Germany
| | - C Sterner
- Medical Cell Biology, University of Regensburg, 93053 Regensburg, Germany
| | - I Tegtmeier
- Medical Cell Biology, University of Regensburg, 93053 Regensburg, Germany
| | - R Warth
- Medical Cell Biology, University of Regensburg, 93053 Regensburg, Germany
| | - S Bandulik
- Medical Cell Biology, University of Regensburg, 93053 Regensburg, Germany
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Abstract
Aldosterone is a steroid hormone synthesized in and secreted from the outer layer of the adrenal cortex, the zona glomerulosa. Aldosterone is responsible for regulating sodium homeostasis, thereby helping to control blood volume and blood pressure. Insufficient aldosterone secretion can lead to hypotension and circulatory shock, particularly in infancy. On the other hand, excessive aldosterone levels, or those too high for sodium status, can cause hypertension and exacerbate the effects of high blood pressure on multiple organs, contributing to renal disease, stroke, visual loss, and congestive heart failure. Aldosterone is also thought to directly induce end-organ damage, including in the kidneys and heart. Because of the significance of aldosterone to the physiology and pathophysiology of the cardiovascular system, it is important to understand the regulation of its biosynthesis and secretion from the adrenal cortex. Herein, the mechanisms regulating aldosterone production in zona glomerulosa cells are discussed, with a particular emphasis on signaling pathways involved in the secretory response to the main controllers of aldosterone production, the renin-angiotensin II system, serum potassium levels and adrenocorticotrophic hormone. The signaling pathways involved include phospholipase C-mediated phosphoinositide hydrolysis, inositol 1,4,5-trisphosphate, cytosolic calcium levels, calcium influx pathways, calcium/calmodulin-dependent protein kinases, diacylglycerol, protein kinases C and D, 12-hydroxyeicostetraenoic acid, phospholipase D, mitogen-activated protein kinase pathways, tyrosine kinases, adenylate cyclase, and cAMP-dependent protein kinase. A complete understanding of the signaling events regulating aldosterone biosynthesis may allow the identification of novel targets for therapeutic interventions in hypertension, primary aldosteronism, congestive heart failure, renal disease, and other cardiovascular disorders.
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Affiliation(s)
- Wendy B Bollag
- Charlie Norwood VA Medical Center, Augusta, Georgia; Department of Physiology, Medical College of Georgia at Georgia Regents University, Augusta, Georgia
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Olala LO, Shapiro BA, Merchen TC, Wynn JJ, Bollag WB. Protein kinase C and Src family kinases mediate angiotensin II-induced protein kinase D activation and acute aldosterone production. Mol Cell Endocrinol 2014; 392:173-81. [PMID: 24859649 PMCID: PMC4120960 DOI: 10.1016/j.mce.2014.05.015] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2014] [Revised: 04/26/2014] [Accepted: 05/14/2014] [Indexed: 12/26/2022]
Abstract
Recent evidence has shown a role for the serine/threonine protein kinase D (PKD) in the regulation of acute aldosterone secretion upon angiotensin II (AngII) stimulation. However, the mechanism by which AngII activates PKD remains unclear. In this study, using both pharmacological and molecular approaches, we demonstrate that AngII-induced PKD activation is mediated by protein kinase C (PKC) and Src family kinases in primary bovine adrenal glomerulosa cells and leads to increased aldosterone production. The pan PKC inhibitor Ro 31-8220 and the Src family kinase inhibitors PP2 and Src-1 inhibited both PKD activation and acute aldosterone production. Additionally, like the dominant-negative serine-738/742-to-alanine PKD mutant that cannot be phosphorylated by PKC, the dominant-negative tyrosine-463-to-phenylalanine PKD mutant, which is not phosphorylatable by the Src/Abl pathway, inhibited acute AngII-induced aldosterone production. Taken together, our results demonstrate that AngII activates PKD via a mechanism involving Src family kinases and PKC, to underlie increased aldosterone production.
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Affiliation(s)
- Lawrence O Olala
- Charlie Norwood VA Medical Center, Augusta, GA 30904, United States; Department of Physiology, Medical College of Georgia at Georgia Regents University, Augusta, GA 30912, United States
| | - Brian A Shapiro
- Institute of Molecular Medicine and Genetics, Medical College of Georgia at Georgia Regents University, Augusta, GA 30912, United States
| | - Todd C Merchen
- Department of Surgery, Medical College of Georgia at Georgia Regents University, Augusta, GA 30912, United States
| | - James J Wynn
- Department of Surgery, Medical College of Georgia at Georgia Regents University, Augusta, GA 30912, United States
| | - Wendy B Bollag
- Charlie Norwood VA Medical Center, Augusta, GA 30904, United States; Department of Physiology, Medical College of Georgia at Georgia Regents University, Augusta, GA 30912, United States; Departments of Cell Biology and Anatomy, Medicine and Orthopaedic Surgery, Medical College of Georgia at Georgia Regents University, Augusta, GA 30912, United States.
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13
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Olala LO, Choudhary V, Johnson MH, Bollag WB. Angiotensin II-induced protein kinase D activates the ATF/CREB family of transcription factors and promotes StAR mRNA expression. Endocrinology 2014; 155:2524-33. [PMID: 24708239 PMCID: PMC4060184 DOI: 10.1210/en.2013-1485] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Aldosterone synthesis is initiated upon the transport of cholesterol from the outer to the inner mitochondrial membrane, where the cholesterol is hydrolyzed to pregnenolone. This process is the rate-limiting step in acute aldosterone production and is mediated by the steroidogenic acute regulatory (StAR) protein. We have previously shown that angiotensin II (AngII) activation of the serine/threonine protein kinase D (PKD) promotes acute aldosterone production in bovine adrenal glomerulosa cells, but the mechanism remains unclear. Thus, the purpose of this study was to determine the downstream signaling effectors of AngII-stimulated PKD activity. Our results demonstrate that overexpression of the constitutively active serine-to-glutamate PKD mutant enhances, whereas the dominant-negative serine-to-alanine PKD mutant inhibits, AngII-induced StAR mRNA expression relative to the vector control. PKD has been shown to phosphorylate members of the activating transcription factor (ATF)/cAMP response element binding protein (CREB) family of leucine zipper transcription factors, which have been shown previously to bind the StAR proximal promoter and induce StAR mRNA expression. In primary glomerulosa cells, AngII induces ATF-2 and CREB phosphorylation in a time-dependent manner. Furthermore, overexpression of the constitutively active PKD mutant enhances the AngII-elicited phosphorylation of ATF-2 and CREB, and the dominant-negative mutant inhibits this response. Furthermore, the constitutively active PKD mutant increases the binding of phosphorylated CREB to the StAR promoter. Thus, these data provide insight into the previously reported role of PKD in AngII-induced acute aldosterone production, providing a mechanism by which PKD may be mediating steroidogenesis in primary bovine adrenal glomerulosa cells.
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Affiliation(s)
- Lawrence O Olala
- Charlie Norwood Veterans Administration Medical Center (L.O.O., V.C., W.B.B.), Augusta, Georgia 30904; and Departments of Physiology (L.O.O., V.C., W.B.B.), Biostatistics and Epidemiology (M.H.J.), and Cell Biology and Anatomy and Medicine and Orthopaedic Surgery (W.B.B.), Medical College of Georgia at Georgia Regents University, Augusta, Georgia 30912
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Rajamohan SB, Raghuraman G, Prabhakar NR, Kumar GK. NADPH oxidase-derived H(2)O(2) contributes to angiotensin II-induced aldosterone synthesis in human and rat adrenal cortical cells. Antioxid Redox Signal 2012; 17:445-59. [PMID: 22214405 PMCID: PMC3365360 DOI: 10.1089/ars.2011.4176] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
BACKGROUND The Renin-Angiotensin-Aldosterone-System plays a pivotal role in hypertension. Angiotensin II (Ang II) is a major regulator of aldosterone synthesis and secretion, and it is known to facilitate reactive oxygen species (ROS) generation in many cell types. AIMS Here, we assessed the role of ROS signaling in Ang II-induced aldosterone synthesis by focusing on the regulation of aldosterone synthase (CYP11B2), a cytochrome P450 oxidase that catalyzes the final step in aldosterone biosynthetic pathway. RESULTS Ang II increased CYP11B2 activity, mRNA and protein with a concomitant elevation of 6-Carboxy- 2',7'-dichlorodihydrofluorescein diacetate fluorescence, malondialdehyde and protein carbonyl levels (indices of ROS), NADPH oxidase (Nox) activity, and H(2)O(2) levels in human and rat adrenal cortical cells. The expression of nuclear receptor related 1 protein, a transcription factor known to regulate CYP11B2 expression, was also augmented by Ang II. These Ang II-evoked effects were either abolished or attenuated by pretreatment of cells with either Ang II type I receptor (AT(1)R) antagonist, or antioxidants or Nox inhibitor or siRNA silencing of Nox1, 2 and 4, or inhibitors of phospholipase C and protein kinase C. Exogenous H(2)O(2) mimicked the facilitatory effects of Ang II on CYP11B2 activity, mRNA, and protein expression, and these changes were significantly reduced by PEG-catalase. INNOVATION ROS, particularly H(2)O(2), is identified as a key regulator of aldosterone production. CONCLUSION Our results suggest that Ang II facilitates CYP11B2 activity and the ensuing aldosterone production via activation of AT(1)R-Nox-H(2)O(2) signaling pathway.
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Affiliation(s)
- Senthilkumar B Rajamohan
- Department of Medicine, Institute for Integrative Physiology, University of Chicago, Chicago, IL 60637-1470, USA
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Kaminska B, Opalka M, Ciereszko R, Dusza L. Are oestrogen receptors and protein tyrosine kinases involved in phytoestrogen-modulated steroid secretion by porcine adrenocortical cells? Acta Vet Hung 2012; 60:285-95. [PMID: 22609998 DOI: 10.1556/avet.2012.024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The phytoestrogens genistein and daidzein had been found to affect the function of some tissues via oestrogen receptors (ER). In addition, genistein, but not daidzein, is considered to be a protein tyrosine kinase (PTK) inhibitor. Thus, the involvement of oestrogen receptors and PTK in phytoestrogen action on adrenocortical porcine steroidogenesis was examined in this study. The aims of the experiment were to test the effects of (i) ICI 182, 780 (ICI), an ER antagonist, on genistein- and daidzein-modulated cortisol and androstenedione (A4) secretion by adrenocortical cells isolated during the luteal and follicular phases of the porcine oestrous cycle; (ii) tyrphostin AG 957 (TAG), a nonsteroidal PTK inhibitor, on cortisol and A4 secretion by the cells and (iii) the phase of the porcine oestrous cycle on the mechanism of phytoestrogen action. Adrenals were harvested during the luteal (n = 5 animals) and follicular (n = 5 animals) phases of the oestrous cycle from locally slaughtered crossbred gilts. The isolated adrenocortical cells were incubated for 8 h (37 °C, 95% air, 5% CO2) with genistein (5 or 10 μM) or daidzein (5 or 10 μM) in the presence or absence of ICI (0.5 μM) or TAG (5 or 10 μM). Genistein and daidzein inhibited cortisol secretion and stimulated A4 secretion by porcine adrenocortical cells harvested during both the luteal and follicular phases of the oestrous cycle. The ER antagonist ICI did not eliminate phytoestrogen-induced changes in steroidogenesis. In contrast to genistein, TAG reduced the secretion of A4 and did not affect cortisol secretion. There was no observable effect due to the phase of the cycle. It is suggested that the mechanism of genistein and daidzein action in the adrenocortical cells of pigs is independent of ER and PTK. It is possible that PTK are involved in A4 secretion by porcine adrenocortical cells.
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Affiliation(s)
- Barbara Kaminska
- 1 University of Warmia and Mazury in Olsztyn Department of Animal Physiology, Faculty of Biology and Biotechnology Oczapowskiego 1A 10-718 Olsztyn Poland
| | - Marek Opalka
- 1 University of Warmia and Mazury in Olsztyn Department of Animal Physiology, Faculty of Biology and Biotechnology Oczapowskiego 1A 10-718 Olsztyn Poland
| | - Renata Ciereszko
- 1 University of Warmia and Mazury in Olsztyn Department of Animal Physiology, Faculty of Biology and Biotechnology Oczapowskiego 1A 10-718 Olsztyn Poland
| | - Luiza Dusza
- 1 University of Warmia and Mazury in Olsztyn Department of Animal Physiology, Faculty of Biology and Biotechnology Oczapowskiego 1A 10-718 Olsztyn Poland
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Kunal SB, Killivalavan A, Medhamurthy R. Involvement of Src family of kinases and cAMP phosphodiesterase in the luteinizing hormone/chorionic gonadotropin receptor-mediated signaling in the corpus luteum of monkey. Reprod Biol Endocrinol 2012; 10:25. [PMID: 22455442 PMCID: PMC3353251 DOI: 10.1186/1477-7827-10-25] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/10/2011] [Accepted: 03/29/2012] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND In higher primates, during non-pregnant cycles, it is indisputable that circulating LH is essential for maintenance of corpus luteum (CL) function. On the other hand, during pregnancy, CL function gets rescued by the LH analogue, chorionic gonadotropin (CG). The molecular mechanisms involved in the control of luteal function during spontaneous luteolysis and rescue processes are not completely understood. Emerging evidence suggests that LH/CGR activation triggers proliferation and transformation of target cells by various signaling molecules as evident from studies demonstrating participation of Src family of tyrosine kinases (SFKs) and MAP kinases in hCG-mediated actions in Leydig cells. Since circulating LH concentration does not vary during luteal regression, it was hypothesized that decreased responsiveness of luteal cells to LH might occur due to changes in LH/CGR expression dynamics, modulation of SFKs or interference with steroid biosynthesis. METHODS Since, maintenance of structure and function of CL is dependent on the presence of functional LH/CGR its expression dynamics as well as mRNA and protein expressions of SFKs were determined throughout the luteal phase. Employing well characterized luteolysis and CL rescue animal models, activities of SFKs, cAMP phosphodiesterase (cAMP-PDE) and expression of SR-B1 (a membrane receptor associated with trafficking of cholesterol ester) were examined. Also, studies were carried out to investigate the mechanisms responsible for decline in progesterone biosynthesis in CL during the latter part of the non-pregnant cycle. RESULTS AND DISCUSSION The decreased responsiveness of CL to LH during late luteal phase could not be accounted for by changes in LH/CGR mRNA levels, its transcript variants or protein. Results obtained employing model systems depicting different functional states of CL revealed increased activity of SFKs [pSrc (Y-416)] and PDE as well as decreased expression of SR-B1 correlating with initiation of spontaneous luteolysis. However, CG, by virtue of its heroic efforts, perhaps by inhibition of SFKs and PDE activation, prevents CL from undergoing regression during pregnancy. CONCLUSIONS The results indicated participation of activated Src and increased activity of cAMP-PDE in the control of luteal function in vivo. That the exogenous hCG treatment caused decreased activation of Src and cAMP-PDE activity with increased circulating progesterone might explain the transient CL rescue that occurs during early pregnancy.
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Affiliation(s)
- Shah B Kunal
- Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bangalore 560012, India
| | - Asaithambi Killivalavan
- Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bangalore 560012, India
| | - Rudraiah Medhamurthy
- Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bangalore 560012, India
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Aritomi S, Wagatsuma H, Numata T, Uriu Y, Nogi Y, Mitsui A, Konda T, Mori Y, Yoshimura M. Expression of N-type calcium channels in human adrenocortical cells and their contribution to corticosteroid synthesis. Hypertens Res 2010; 34:193-201. [DOI: 10.1038/hr.2010.191] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Qin H, Kent P, Isales CM, Parker PM, Wilson MV, Bollag WB. The role of calcium influx pathways in phospholipase D activation in bovine adrenal glomerulosa cells. J Endocrinol 2009; 202:77-86. [PMID: 19372190 PMCID: PMC3743046 DOI: 10.1677/joe-09-0119] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The steroid hormone aldosterone maintains sodium homeostasis and is therefore important in the control of blood volume and pressure. Angiotensin II (AngII) and elevated extracellular potassium concentrations ([K(+)](e)), the prime physiologic regulators of aldosterone secretion from adrenal glomerulosa cells, activate phospholipase D (PLD) in these cells. The role of Ca(2+) in the activation by these agents is unknown, although nitrendipine, a voltage-dependent Ca(2+) channel antagonist, does not inhibit AngII-elicited PLD activation, despite the fact that this compound blocked elevated [K(+)](e)-stimulated PLD activity. PLD activation triggered by AngII was also unaffected by the T-type calcium channel inhibitor nickel. Nevertheless, Ca(2+) influx was required for AngII-induced PLD activation in both primary cultures of bovine adrenal glomerulosa cells and a glomerulosa cell model, the NCI H295R adrenocortical carcinoma cell line. The involvement of store-operated Ca(2+) (SOC) influx and Ca(2+) release-activated Ca(2+) (CRAC) influx pathways in PLD activation was investigated using thapsigargin, an endoplasmic reticulum Ca(2+) pump inhibitor that empties the store to induce SOC influx, and the SOC inhibitor YM-58483 (BTP2), as well as a CRAC inhibitor, tyrphostin A9. In bovine glomerulosa cells, tyrphostin A9 inhibited AngII-induced PLD activation without affecting elevated [K(+)](e)-stimulated enzyme activity. On the other hand, differences were observed between the bovine adrenal glomerulosa and H295R cells in the involvement of Ca(2+) influx pathways in PLD activation, with the involvement of the SOC pathway suggested in the H295R cells. In summary, our results indicate that Ca(2+) entry only through certain Ca(2+) influx pathways is linked to PLD activation.
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Affiliation(s)
- Haixia Qin
- Institute of Molecular Medicine and Genetics, Medical College of Georgia, 1120 15 Street, Augusta, GA 30912
| | - Patricia Kent
- Institute of Molecular Medicine and Genetics, Medical College of Georgia, 1120 15 Street, Augusta, GA 30912
| | - Carlos M. Isales
- Institute of Molecular Medicine and Genetics, Medical College of Georgia, 1120 15 Street, Augusta, GA 30912
- Department of Orthopaedic Surgery, Medical College of Georgia, 1120 15 Street, Augusta, GA 30912
| | - Peter M. Parker
- Institute of Molecular Medicine and Genetics, Medical College of Georgia, 1120 15 Street, Augusta, GA 30912
| | - Mariya V. Wilson
- Institute of Molecular Medicine and Genetics, Medical College of Georgia, 1120 15 Street, Augusta, GA 30912
| | - Wendy B. Bollag
- Charlie Norwood VA Medical Center, One Freedom Way, Augusta, GA 30904
- Institute of Molecular Medicine and Genetics, Medical College of Georgia, 1120 15 Street, Augusta, GA 30912
- Departments of Medicine and Cell Biology and Anatomy, Medical College of Georgia, 1120 15 Street, Augusta, GA 30912
- Department of Orthopaedic Surgery, Medical College of Georgia, 1120 15 Street, Augusta, GA 30912
- Address correspondence to: Institute of Molecular Medicine and Genetics, Medical College of Georgia, 1120 15 Street, Augusta, GA 30912, Tel. 706-721-0698; Fax 706-721-7915;
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Nogueira EF, Xing Y, Morris CAV, Rainey WE. Role of angiotensin II-induced rapid response genes in the regulation of enzymes needed for aldosterone synthesis. J Mol Endocrinol 2009; 42:319-30. [PMID: 19158234 PMCID: PMC4176876 DOI: 10.1677/jme-08-0112] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Aldosterone is principally synthesized in the zona glomerulosa of the adrenal by a series of enzymatic reactions leading to the conversion of cholesterol to aldosterone. Angiotensin II (Ang II) is the major physiological regulator of aldosterone production acting acutely to stimulate aldosterone biosynthesis and chronically to increase the capacity of the adrenals to produce aldosterone. We previously defined eight transcription factors that are rapidly induced following Ang II treatment using three in vitro adrenocortical cell models. Herein, we investigated the function of these transcription factors in the regulation of the enzymes needed for aldosterone production. H295R adrenal cells were co-transfected with expression vectors for each transcription factor and promoter/reporter constructs prepared for genes encoding the enzymes needed for aldosterone production. NGFI-B family members induced promoter activity of 3-beta-hydroxysteroid-dehydrogenase type 2 (HSD3B2), 21-hydroxylase (CYP21A2), and aldosterone synthase (CYP11B2). The importance of NGFI-B in the regulation of CYP11B2 was also demonstrated by reduced CYP11B2 transcription in the presence of a dominant-negative-NGFI-B. A pharmacological approach was used to characterize the Ang II pathways regulating transcription of NGFI-B family genes. Transcription of NGFI-B members were decreased following inhibition of Ang II type 1 receptor (AT1R), protein kinase C (PKC), calcium/calmodulin-dependent kinases (CaMK), and Src tyrosine kinase (SRC). Taken together, these results suggest that Ang II binding to the AT1R increases activity of PKC, CaMK, and SRC, which act to increase expression of the family of NGFI-B genes as well as CYP11B2. Ang II induction of the NGFI-B family members represents an important pathway to increase the capacity of adrenal cells to produce aldosterone.
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Affiliation(s)
- Edson F Nogueira
- Department of Physiology, Medical College of Georgia, Augusta, Georgia 30912, USA
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Trost M, English L, Lemieux S, Courcelles M, Desjardins M, Thibault P. The phagosomal proteome in interferon-gamma-activated macrophages. Immunity 2009; 30:143-54. [PMID: 19144319 DOI: 10.1016/j.immuni.2008.11.006] [Citation(s) in RCA: 185] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2008] [Revised: 10/31/2008] [Accepted: 11/11/2008] [Indexed: 10/21/2022]
Abstract
The ability of macrophages to clear pathogens and elicit a sustained immune response is regulated by various cytokines, including interferon-gamma (IFN-gamma). To investigate the molecular mechanisms by which IFN-gamma modulates phagosome functions, we profiled the changes in composition, abundance, and phosphorylation of phagosome proteins in resting and activated macrophages by using quantitative proteomics and bioinformatics approaches. We identified 2415 phagosome proteins together with 2975 unique phosphorylation sites with a high level of sensitivity. Using network analyses, we determined that IFN-gamma delays phagosomal acquisition of lysosomal hydrolases and peptidases for the gain of antigen presentation. Furthermore, this gain in antigen presentation is dependent on phagosomal networks of the actin cytoskeleton and vesicle-trafficking proteins, as well as Src kinases and calpain proteases. Major histocompatibility complex class I antigen-presentation assays validated the molecular participation of these networks in the enhanced capacity of IFN-gamma-activated macrophages to crosspresent exogenous antigens to CD8(+) T cells.
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Affiliation(s)
- Matthias Trost
- Department of Pathology and Cell Biology, Université de Montréal, Succ Centre-ville, Montréal, Québec, Canada
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Genistein-Induced Histomorphometric and Hormone Secreting Changes in the Adrenal Cortex in Middle-Aged Rats. Exp Biol Med (Maywood) 2009; 234:148-56. [DOI: 10.3181/0807-rm-231] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The soybean phytoestrogen, genistein, is increasingly consumed as an alternative therapeutic for age-related diseases, namely cardiovascular conditions, cancer and osteoporosis. Besides estrogenic/antiestrogenic action, this isoflavone exerts a prominent inhibitory effect on tyrosine kinase and the steroidogenic enzyme families, thus affecting hormonal homeostasis. The aim of this study was to examine the effects of genistein on: histomorphometric features of the adrenal cortex, blood concentrations of aldosterone, corticosterone and dehydroepiandrosterone (DHEA) and adrenal tissue corticosterone content in orchidectomized middle-aged male rats. Sixteen-month-old Wistar rats were divided into sham-operated (SO), orchidectomized (Orx) and genistein-treated orchidectomized (Orx+G) groups. Genistein (30 mg/kg/day) was administered subcutaneously for three weeks, while the control groups received the vehicle alone. The adrenal cortex was analysed histologically and morphometrically. Circulating concentrations of aldosterone, corticosterone and DHEA, as well as adrenal tissue corticosterone levels, were determined by immunoassay. When compared to the SO group, orchidectomy decreased the ZG and ZR cell volume by 43% and 29%, respectively ( P < 0.05). Serum concentrations of aldosterone and DHEA were markedly lower [13% and 41%, respectively ( P < 0.05)], while serum and adrenal tissue levels of corticosterone did not change after orchidectomy. Orchidectomy followed by genistein treatment increased the ZG, ZF and ZR cell volume by 54%, 34% and 77%, respectively ( P < 0.05), compared to the untreated orchidectomized group. Histological analysis revealed noticeable vacuolization of the ZG and ZF cells in the Orx+G group. Serum aldosterone and corticosterone concentrations together with adrenal tissue corticosterone were 47%, 31% and 44% lower, respectively ( P < 0.05), whereas serum DHEA concentration was 342% higher ( P < 0.05) in this group in comparison with the Orx group. This study shows that in orchidectomized middle-aged rats, genistein can cause the shunting of metabolic pathways in the adrenals, supporting DHEA secretion and inhibiting corticosterone and aldosterone secretion.
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Brenner T, O'Shaughnessy KM. Both TASK-3 and TREK-1 two-pore loop K channels are expressed in H295R cells and modulate their membrane potential and aldosterone secretion. Am J Physiol Endocrinol Metab 2008; 295:E1480-6. [PMID: 18854423 DOI: 10.1152/ajpendo.90652.2008] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The rate of aldosterone synthesis by adrenal glomerulosa cells relies on the selective permeability of the glomerulosa cell to K(+) ions. In rodent and bovine adrenal glomerulosa cells, this background potassium current is provided by a two-pore loop potassium (K2P) channel: largely TASK-3 in the rat and TREK-1 in the cow. The nature of the K2P channel in the human adrenal cortex is not known, and we have addressed this issue here using the H295R human adrenal cell line. We show that these cells express mRNA and protein for both TASK-3 and TREK-1 K2P channels. Using a potentiometric dye (FMP), we also show that TASK-3 and TREK-1 channel modulators can affect the membrane potential of H295R cells. Transfecting H295R cells with TASK-3 or TREK-1 dominant-negative mutants (TASK-3 G95E or TREK-1 G144E) produced depolarization of H295R cells and altered K-stimulated aldosterone secretion. Finally, transfection of a constitutively active mutant of Galpha(q) into H295R cells (GTPase-deficient Galpha(q)-QL) depolarized them and increased basal aldosterone secretion. Taken together, our data support both TASK-3 and TREK-1 as being functionally operational in the H295R cell line. This suggests that human adrenal glomerulosa cells may utilize both of these K2P channels for their background potassium current.
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Affiliation(s)
- Tanja Brenner
- Department of Medicine, University of Cambridge, Cambridge, UK
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Chaturvedi G, Arai K, Terranova PF, Roby KF. The Src tyrosine kinase pathway regulates thecal CYP17 expression and androstenedione secretion. Mol Cell Biochem 2008; 318:191-200. [PMID: 18642057 DOI: 10.1007/s11010-008-9871-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2007] [Accepted: 07/03/2008] [Indexed: 11/25/2022]
Abstract
In order to evaluate the role of Src tyrosine kinase in thecal cell steroidogenesis, a pharmacological approach was utilized by treating enriched populations of mouse ovarian theca-interstitial cells in vitro with a direct Src kinase inhibitor, PP2. Inhibition of Src with PP2 increased both basal and forskolin-stimulated androstenedione secretion, and increased cytochrome P450 17-alpha hydroxylase-lyase (CYP17) promoter activity and steady state mRNA. PP2 did not change thecal levels of StAR mRNA. Inhibition of mitogen-activated protein kinase kinase, a downstream regulator of Src activity, using PD98059 also increased forskolin-stimulated secretion of androstenedione above forskolin alone, but had no effect on basal secretion of androstenedione. Src inhibition increased mitogen-activated protein kinase phosphatase-1 protein and decreased phosphorylation of SF-1, which correlated with increased CYP17 promoter activity and mRNA levels. These results implicate Src tyrosine kinase in the regulation of CYP17 and thecal androgen secretion.
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Affiliation(s)
- Gaurav Chaturvedi
- Department of Molecular and Integrative Physiology, The Center for Reproductive Sciences, University of Kansas Medical Center, Kansas City, KS 66160, USA
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Adenosine-stimulated adrenal steroidogenesis involves the adenosine A2A and A2B receptors and the Janus kinase 2–mitogen-activated protein kinase kinase–extracellular signal-regulated kinase signaling pathway. Int J Biochem Cell Biol 2008; 40:2815-25. [DOI: 10.1016/j.biocel.2008.05.016] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2008] [Revised: 05/15/2008] [Accepted: 05/29/2008] [Indexed: 11/22/2022]
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25
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Sewer MB, Dammer EB, Jagarlapudi S. Transcriptional regulation of adrenocortical steroidogenic gene expression. Drug Metab Rev 2007; 39:371-88. [PMID: 17786627 DOI: 10.1080/03602530701498828] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
By serving as ligands for nuclear and plasma membrane receptors, steroid hormones are key regulators of a diverse array of physiological processes. These hormones are synthesized from cholesterol in tissues such as the adrenal cortex, ovaries, testes, and placenta. Because steroid hormones control the expression of numerous genes, steroidogenic cells utilize multiple mechanisms that ensure tight control of the synthesis of these molecules. This review will give an overview of the molecular mechanisms by which the expression of steroidogenic genes is regulated in the human adrenal cortex.
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Affiliation(s)
- Marion B Sewer
- School of Biology and Parker H. Petit Institute for Bioengineering & Biosciences, Georgia Institute of Technology, Atlanta, Georgia 30332-0230, USA.
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Shah BH, Baukal AJ, Chen HD, Shah AB, Catt KJ. Mechanisms of endothelin-1-induced MAP kinase activation in adrenal glomerulosa cells. J Steroid Biochem Mol Biol 2006; 102:79-88. [PMID: 17113976 PMCID: PMC3196343 DOI: 10.1016/j.jsbmb.2006.09.026] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
G protein-coupled receptors (GPCRs) such as angiotensin II, bradykinin and endothelin-1 (ET-1) are critically involved in the regulation of adrenal function, including aldosterone production from zona glomerulosa cells. Whereas, substantial data are available on the signaling mechanisms of ET-1 in cardiovascular tissues, such information in adrenal glomerulosa cells is lacking. Bovine adrenal glomerulosa (BAG) cells express receptors for endothelin-1 (ET-1) and their stimulation caused phosphorylation of Src (at Tyr416), proline-rich tyrosine kinase (Pyk2 at Tyr402), extracellularly regulated signal kinases (ERK1/2), and their dependent proteins, p90 ribosomal S6 kinase (RSK-1) and CREB. ET-1 elicited these responses predominantly through activation of a G(i)-linked cascade with a minor contribution from the G(q)/PKC pathway. Whereas, selective inhibition of EGF-R kinase with AG1478 caused complete inhibition of EGF-induced ERK/RSK-1/CREB activation, it caused only partial reduction (30-40%) of such ET-1-induced responses. Consistent with this, inhibition of matrix metalloproteinases (MMPs) with GM6001 reduced ERK1/2 activation by ET-1, consistent with partial involvement of the MMP-dependent EGF-R activation in this cascade. Activation of ERK/RSK-1/CREB by both ET-1 and EGF was abolished by inhibition of Src, indicating its central role in ET-1 signaling in BAG cells. Moreover, the signaling characteristics of ET-1 in cultured BAG cells closely resembled those observed in clonal adrenocortical H295R cells. The ET-1-induced proliferation of BAG and H295 R cells was much smaller than that induced by Ang II or FGF. These data demonstrate that ET-1 causes ERK/RSK-1/CREB phosphorylation predominantly through activation of G(i) and Src, with a minor contribution from MMP-dependent EGF-R transactivation.
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Affiliation(s)
- Bukhtiar H Shah
- Endocrinology and Reproduction Research Branch, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
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Chen YC, Chang MF, Chen Y, Wang SM. Signaling pathways of magnolol-induced adrenal steroidogensis. FEBS Lett 2005; 579:4337-43. [PMID: 16061232 DOI: 10.1016/j.febslet.2005.06.068] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2005] [Revised: 06/24/2005] [Accepted: 06/27/2005] [Indexed: 11/20/2022]
Abstract
This study focused on identifying the signalling mediating the effect of magnolol on corticosterone production. Magnolol-induced corticosterone production was completely inhibited by mitogen-activated protein kinase kinase (MEK)-inhibitor PD98059, tyrosine kinase (TK)-inhibitor genistein or Janus tyrosine kinase 2 (JAK2)-inhibitor AG490, suggesting that extracellular signal-regulated kinase (ERK) and JAK2 are both involved in this signaling cascade. Further, magnolol induced the transient phosphorylation of MEK, ERK, cAMP response-element binding protein (CREB) and the expression of 32 and 30 kDa steroidogenic acute regulatory protein (StAR) in a time-dependent manner. Inhibition of TK or JAK2 activities blocked magnolol-induced phosphorylation of MEK and ERK, again supporting the upstream role of JAK2. The activation of JAK2 or MEK apparently mediated the magnolol-induced phosphorylation of CREB and the upregulation of StAR. These findings demonstrate a novel pathway for magnolol to induce the expression of StAR, which regulates the rate-limiting step in sterodiogenesis.
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Affiliation(s)
- Yung-Chia Chen
- Department of Anatomy and Cell Biology, College of Medicine, National Taiwan University, 1-1 Jen-Ai Road, Taipei, Taiwan
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Shah BH, Baukal AJ, Shah FB, Catt KJ. Mechanisms of extracellularly regulated kinases 1/2 activation in adrenal glomerulosa cells by lysophosphatidic acid and epidermal growth factor. Mol Endocrinol 2005; 19:2535-48. [PMID: 15928312 DOI: 10.1210/me.2005-0082] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
The regulation of adrenal function, including aldosterone production from adrenal glomerulosa cells, is dependent on a variety of G protein-coupled receptors (GPCRs) and receptor tyrosine kinases (RTKs). In many cell types, GPCR-mediated MAPK activation is mediated through transactivation of RTKs, in particular the epidermal growth factor (EGF) receptor (EGF-R). However, the extent to which this cross-communication between GPCRs and RTKs is operative in the adrenal glomerulosa has not been defined. Bovine adrenal glomerulosa cells express receptors for lysophosphatidic acid (LPA) and EGF. In cultured bovine adrenal glomerulosa cells, LPA, which is predominantly coupled to Gi and partially to Gq/protein kinase C alpha and epsilon, caused phosphorylation of Src (at Tyr416), proline-rich tyrosine kinase (Pyk2 at Tyr402), EGF-R, protein kinase B/Akt, extracellularly regulated signal kinases 1/2, and their dependent protein, p90 ribosomal S6 kinase. Overexpression of dominant negative mutants of Ras or EGF-R, and selective inhibition of EGF-R kinase with AG1478, significantly reduced LPA-induced ERK1/2 phosphorylation. However, this was not impaired by inhibition of matrix metalloproteinase (MMP) and heparin-binding EGF. LPA-induced ERK1/2 activation occurs predominantly through EGF-R transactivation by Gi/Src and partly through activation of protein kinase C, which acts downstream of EGF-R and Ras. In contrast, LPA-induced phosphorylation of Shc and ERK1/2 in clonal hepatocytes (C9 cells) was primarily mediated through MMP-dependent transactivation of the EGF-R. These observations in adrenal glomerulosa and hepatic cells demonstrate that LPA phosphorylates ERK1/2 through EGF-R transactivation in a MMP-dependent or -independent manner in individual target cells. This reflects the ability of GPCRs expressed in cell lines and neoplastic cells to utilize distinct signaling pathways that can elicit altered responses compared with those of native tissues.
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Affiliation(s)
- Bukhtiar H Shah
- Endocrinology and Reproduction Research Branch, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda Maryland 20892-4510, USA.
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Coulter CL. Functional biology of the primate fetal adrenal gland: advances in technology provide new insight. Clin Exp Pharmacol Physiol 2005; 31:475-84. [PMID: 15298538 DOI: 10.1111/j.1440-1681.2004.04031.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
1. The main aim of the present review is to summarize recent experimental data from human and non-human primate models that have identified factors essential for adrenal development and other factors that may determine the regulation of the specific structural organization and function of the adrenal gland. 2. The fetal adrenal cortex has two morphologically distinct zones, with the outer definitive zone being comprised of tightly packed small cells, which appear to be steroidogenically quiescent until late gestation, and the inner fetal zone, which appears to be steroidogenically active throughout gestation. 3. In the primate fetus, growth of the adrenal gland involves hyperplasia, hypertrophy, migration and senescence. Cells appear to proliferate in the external portion of the definitive zone and then move centripetally and become non-proliferative in the fetal zone, where they acquire their steroidogenic capacities. 4. A variety of new technologies has been used to identify zonal-specific markers of the cortical zones within the developing human fetal adrenal gland. On microarray, 67 transcripts showed a minimum of a 2.5-fold difference between the fetal and adult adrenal gland. The vast majority of these genes had not been studied in relation to adrenal gland development or function. In combination with techniques such as laser capture microdissection, which has allowed the isolation of fairly pure zone-specific cell populations from the human fetal adrenal cortex, we can begin to unravel the complex interactions regulating adrenal growth and functional differentiation.
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Affiliation(s)
- Catherine L Coulter
- Centre for the Early Origins of Adult Health, Discipline of Physiology, School of Molecular and Biomedical Science, University of Adelaide, Adelaide, South Australia, Australia.
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Priester J, Smith WA. Inhibition of tyrosine phosphorylation blocks hormone-stimulated calcium influx in an insect steroidogenic gland. Mol Cell Endocrinol 2005; 229:185-92. [PMID: 15607542 DOI: 10.1016/j.mce.2004.07.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2004] [Revised: 06/30/2004] [Accepted: 07/06/2004] [Indexed: 01/29/2023]
Abstract
In the tobacco hornworm Manduca sexta (M. sexta) as in other insects, ecdysone synthesis occurs in the prothoracic glands and is stimulated by the brain neuropeptide prothoracicotropic hormone (PTTH). PTTH activates the prothoracic glands through the second messenger cAMP, the synthesis of which is stimulated by calcium. We previously found that the Src kinase inhibitor 4-amino-5-(4-methylphenyl)-7-(t-butyl)pyrazolo[3,4-D]-pyrimidine (PP1) inhibits PTTH-stimulated cAMP synthesis and ecdysone secretion. In the present study, we show that by contrast, PP1 does not block cAMP synthesis stimulated by the calcium ionophore A23187, and that PP1 augments A23187-stimulated ecdysone secretion. Hence, once glandular levels of calcium are elevated, Src family kinase activity is no longer needed for, and may actually inhibit, steroidogenesis. PP1 blocks calcium influx in PTTH-stimulated prothoracic glands, indicating that tyrosine phosphorylation by a member of the Src kinase family is required for calcium influx. These results suggest that prothoracic gland calcium channels are regulated either directly or indirectly by tyrosine phosphorylation.
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Affiliation(s)
- Jennifer Priester
- Department of Biology, 433 Richards Hall, Northeastern University, 360 Huntington Ave, Boston, MA 02115, USA
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Abstract
Angiotensin II (Ang II)-stimulated aldosterone production in adrenocortical glomerulosa cells requires de novo expression of the steroidogenic acute regulatory protein (StAR). We previously reported that StAR mRNA levels and promoter-reporter gene activity in transiently transfected H295R human adrenocortical cells were stimulated by Ang II and the goals for the current study were to identify signaling pathways activated by Ang II that contribute to StAR transcriptional activation. Using StAR promoter-reporter gene activity and pharmacological inhibition of signaling pathways, we have shown that Ang II-stimulated StAR transcription in H295R cells is dependent upon both influx of external Ca2+ and tyrosine kinase signaling and is enhanced by protein kinase C and mitogen-activated protein kinase (ERK1/2) activation. In particular, Janus tyrosine kinase-2 (Jak2) activation was increased with Ang-II treatment of H295R cells and the select Jak2 inhibitor, AG490, blocked Ang II-dependent Jak2 activation, StAR reporter gene activity, and steroid production. The Ang II-dependent, but not (Bu)2cAMP-dependent, induction of StAR mRNA was also blocked by AG490 and shown to be sensitive to cycloheximide treatment. Together our data support Jak2 as a novel pathway in the Ang II-dependent activation of StAR expression and steroidogenesis in adrenocortical cells and indicate a requirement for ongoing protein synthesis in Ang II-mediated StAR transcription.
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Affiliation(s)
- Barbara J Clark
- Department of Biochemistry and Molecular Biology, University of Louisville, School of Medicine, Louisville, KY 40292, USA.
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Chaturvedi G, Arai K, Limback D, Roby KF, Terranova PF. Src tyrosine kinase regulates CYP17 expression and androstenedione secretion in theca-enriched mouse ovarian cells. Endocrine 2004; 25:147-54. [PMID: 15711029 DOI: 10.1385/endo:25:2:147] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/23/2004] [Revised: 11/04/2004] [Accepted: 11/08/2004] [Indexed: 01/08/2023]
Abstract
Src tyrosine kinase belongs to a non-receptor tyrosine kinase family and has been shown to be involved in G protein-coupled receptor desensitization and internalization. Stimulation of ovarian thecal cells with lutein-izing hormone (LH) activates adenylyl cyclase via a G protein-coupled LH receptor leading to an increase in cAMP. Subsequently, cAMP activates protein kinase A (PKA) that increases steroidogenesis. In order to evaluate the role of Src in thecal cell steroidogenesis, a pharmacological approach was utilized by treating a population of mouse ovarian theca-enriched cells (TEC) in vitro with two Src inhibitors, geldanamycin (GA) and herbimycin A (HA). Treatment of TEC with either GA or HA increased basal androstenedione secretion without alteration of cAMP. In the presence of forskolin, GA and HA treatment further increased androstenedione secretion. RT-PCR analysis of RNA from cells treated with GA for 8, 24, and 48 h revealed that GA increased cytochrome P450 17alpha-hydroxylase/lyase (CYP17) mRNA at 48 h. CYP17 promoter activity also increased after treatment of cells with GA and after co-transfection with a Src dominant negative plasmid. Inhibition of PKA using H89 blocked the effect GA and HA on androstenedione secretion. These results indicate that the pharmacological inhibitors of Src, GA and HA, tested in vitro increased thecal CYP17 promoter activity, CYP17 mRNA, and androstenedione secretion. In addition, GA and HA induced thecal androstenedione secretion may be cAMP independent but possibly requires PKA.
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Affiliation(s)
- Gaurav Chaturvedi
- Department of Molecular and Integrative Physiology, The Center for Reproductive Sciences, Kansas University Medical Center, Kansas City, KS 66160, USA
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Spät A, Hunyady L. Control of aldosterone secretion: a model for convergence in cellular signaling pathways. Physiol Rev 2004; 84:489-539. [PMID: 15044681 DOI: 10.1152/physrev.00030.2003] [Citation(s) in RCA: 344] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Aldosterone secretion by glomerulosa cells is stimulated by angiotensin II (ANG II), extracellular K(+), corticotrophin, and several paracrine factors. Electrophysiological, fluorimetric, and molecular biological techniques have significantly clarified the molecular action of these stimuli. The steroidogenic effect of corticotrophin is mediated by adenylyl cyclase, whereas potassium activates voltage-operated Ca(2+) channels. ANG II, bound to AT(1) receptors, acts through the inositol 1,4,5-trisphosphate (IP(3))-Ca(2+)/calmodulin system. All three types of IP(3) receptors are coexpressed, rendering a complex control of Ca(2+) release possible. Ca(2+) release is followed by both capacitative and voltage-activated Ca(2+) influx. ANG II inhibits the background K(+) channel TASK and Na(+)-K(+)-ATPase, and the ensuing depolarization activates T-type (Ca(v)3.2) Ca(2+) channels. Activation of protein kinase C by diacylglycerol (DAG) inhibits aldosterone production, whereas the arachidonate released from DAG in ANG II-stimulated cells is converted by lipoxygenase to 12-hydroxyeicosatetraenoic acid, which may also induce Ca(2+) signaling. Feedback effects and cross-talk of signal-transducing pathways sensitize glomerulosa cells to low-intensity stimuli, such as physiological elevations of [K(+)] (< or =1 mM), ANG II, and ACTH. Ca(2+) signaling is also modified by cell swelling, as well as receptor desensitization, resensitization, and downregulation. Long-term regulation of glomerulosa cells involves cell growth and proliferation and induction of steroidogenic enzymes. Ca(2+), receptor, and nonreceptor tyrosine kinases and mitogen-activated kinases participate in these processes. Ca(2+)- and cAMP-dependent phosphorylation induce the transfer of the steroid precursor cholesterol from the cytoplasm to the inner mitochondrial membrane. Ca(2+) signaling, transferred into the mitochondria, stimulates the reduction of pyridine nucleotides.
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Affiliation(s)
- András Spät
- Dept. of Physiology, Semmelweis University, Faculty of Medicine, PO Box 259, H-1444 Budapest, Hungary.
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Abstract
Aldosterone, the primary human mineralocorticoid, is a major regulator of intravascular volume and blood pressure. The capacity of the adrenal gland to produce aldosterone is controlled, in large part, by the regulated transcription of CYP11B2, the gene encoding aldosterone synthase. Aldosterone synthase is responsible for the conversion of 11-deoxycorticosterone to aldosterone and is expressed only within the zona glomerulosa of the adrenal cortex. The development of new systems for in vitro studies of expression has helped define molecular mechanisms that regulate this enzyme and thus the capacity of the adrenal gland to produce aldosterone. Both potassium and angiotensin II (ANG II) increase intracellular calcium levels, which regulate expression of CYP11B2 through transcription factors that interact with defined sites in the 5'-flanking region of the gene.
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Affiliation(s)
- Mary H Bassett
- Department of Obstetrics and Gynecology, Division of Reproductive Endocrinology, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX 75235-9032, USA
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Abstract
In the adrenal glomerulosa cell, aldosterone is synthesized from cholesterol, which is supplied to the cell and stored under the form of cholesterol esters, then hydrolyzed to be transferred to the mitochondrial outer membrane and finally transported to the inner membrane where the P450 side-chain cleavage enzyme will convert it to pregnenolone. Angiotensin II (AngII), one of the major physiological regulators of mineralocorticoid synthesis, appears to affect most of the steps along this cascade and thus to exert a powerful control over the use of cholesterol for aldosterone production.
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Affiliation(s)
- Alessandro M Capponi
- Division of Endocrinology, Diabetology and Nutrition, Faculty of Medicine, University Hospital, 24 rue Micheli-du-Crest, CH-1211 Geneva 14, Switzerland.
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Li J, Feltzer RE, Dawson KL, Hudson EA, Clark BJ. Janus Kinase 2 and Calcium Are Required for Angiotensin II-dependent Activation of Steroidogenic Acute Regulatory Protein Transcription in H295R Human Adrenocortical Cells. J Biol Chem 2003; 278:52355-62. [PMID: 14565954 DOI: 10.1074/jbc.m305232200] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Angiotensin II- and K+-stimulated aldosterone production in the adrenocortical glomerulosa cells requires induction of the steroidogenic acute regulatory protein (StAR). While both agents activate Ca2+ signaling, the mechanisms leading to aldosterone synthesis are distinct, and the angiotensin II response cannot be mimicked by K+. We previously reported that StAR mRNA levels and promoter-reporter gene activity in transiently transfected H295R human adrenocortical cells were stimulated by angiotensin II but not by K+ treatment. The current study focused on identifying signaling pathways activated by angiotensin II that contribute to StAR transcriptional activation. We show that the angiotensin II-stimulated transcriptional activation of StAR was dependent upon influx of external calcium and requires protein kinase C activation. Furthermore we describe for the first time that the Janus tyrosine kinase family member, JAK2, was activated by angiotensin II treatment of H295R cells. Treatment of the cells with AG490, a selective inhibitor of JAK2, blocked JAK2 activation and StAR reporter gene activity and inhibited steroid production. Taken together these studies describe a novel pathway controlling StAR expression and steroidogenesis in adrenocortical cells.
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Affiliation(s)
- Jianghong Li
- Department of Biochemistry and Molecular Biology, School of Medicine, University of Louisville, Louisville, Kentucky 40292, USA
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Hsieh HG, Loong CC, Lin CY. Interleukin-17 induces src/MAPK cascades activation in human renal epithelial cells. Cytokine 2003; 19:159-74. [PMID: 12297109 DOI: 10.1006/cyto.2002.1952] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Interleukin-17 (IL-17) is a T cell derived pro-inflammatory cytokine exhibiting multiple biological activities in a variety of cells. In our previous study, we found that IL-17 expressed early on borderline change of renal allograft rejection by Banff classification both in rat renal allograft model and human renal specimens. Renal epithelial cells (RECs) are the important targets in renal allograft rejection. The purpose of this study was to explore the signalling pathways by which human interleukin-17 (hIL-17) contributes to renal allograft rejection by inducing IL-6, IL-8 and MCP-1 expression in human renal epithelial cells (hRECs). Using reverse transcriptase-polymerase chain reaction (RT-PCR), immunoprecipitation and western blot analysis, we report that the early signalling events triggered by the hIL-17 involved tyrosyl phosphorylation of proteins and increased the levels of IL-6, IL-8 and MCP-1 in a dose-dependent manner. Tyrosyl phosphorylation of proteins was induced by IL-17 in 1 min and peaked in 5 min. Further, IL-17 induced the phosphorylation of src kinase and mitogen-activated protein (MAP) kinase. Using a specific src kinase inhibitor, PP2, to treat the hRECs before hIL-17 stimulation, we found that PP2 not only inhibited the phosphorylation of src kinase but also inhibited IL-6, IL-8 and MCP-1 mRNA expression, in a dose-dependent manner. These findings provide the first evidence that the mechanism of IL-17 signalling involves src/MAPK cascades activation.
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Affiliation(s)
- Hsian-Guey Hsieh
- Department of Education and Medical Research, Taipei Veterans General Hospital, Taipei, Taiwan, Republic of China
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