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Johnston JG, Welch AK, Cain BD, Sayeski PP, Gumz ML, Wingo CS. Aldosterone: Renal Action and Physiological Effects. Compr Physiol 2023; 13:4409-4491. [PMID: 36994769 DOI: 10.1002/cphy.c190043] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/31/2023]
Abstract
Aldosterone exerts profound effects on renal and cardiovascular physiology. In the kidney, aldosterone acts to preserve electrolyte and acid-base balance in response to changes in dietary sodium (Na+ ) or potassium (K+ ) intake. These physiological actions, principally through activation of mineralocorticoid receptors (MRs), have important effects particularly in patients with renal and cardiovascular disease as demonstrated by multiple clinical trials. Multiple factors, be they genetic, humoral, dietary, or otherwise, can play a role in influencing the rate of aldosterone synthesis and secretion from the adrenal cortex. Normally, aldosterone secretion and action respond to dietary Na+ intake. In the kidney, the distal nephron and collecting duct are the main targets of aldosterone and MR action, which stimulates Na+ absorption in part via the epithelial Na+ channel (ENaC), the principal channel responsible for the fine-tuning of Na+ balance. Our understanding of the regulatory factors that allow aldosterone, via multiple signaling pathways, to function properly clearly implicates this hormone as central to many pathophysiological effects that become dysfunctional in disease states. Numerous pathologies that affect blood pressure (BP), electrolyte balance, and overall cardiovascular health are due to abnormal secretion of aldosterone, mutations in MR, ENaC, or effectors and modulators of their action. Study of the mechanisms of these pathologies has allowed researchers and clinicians to create novel dietary and pharmacological targets to improve human health. This article covers the regulation of aldosterone synthesis and secretion, receptors, effector molecules, and signaling pathways that modulate its action in the kidney. We also consider the role of aldosterone in disease and the benefit of mineralocorticoid antagonists. © 2023 American Physiological Society. Compr Physiol 13:4409-4491, 2023.
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Affiliation(s)
- Jermaine G Johnston
- Division of Nephrology, Hypertension and Renal Transplantation, Department of Medicine, University of Florida, Gainesville, Florida, USA
- Department of Physiology and Functional Genomics, University of Florida, Gainesville, Florida, USA
- Nephrology Section, Veteran Administration Medical Center, North Florida/South Georgia Malcom Randall Department of Veterans Affairs Medical Center, Gainesville, Florida, USA
| | - Amanda K Welch
- Division of Nephrology, Hypertension and Renal Transplantation, Department of Medicine, University of Florida, Gainesville, Florida, USA
- Nephrology Section, Veteran Administration Medical Center, North Florida/South Georgia Malcom Randall Department of Veterans Affairs Medical Center, Gainesville, Florida, USA
| | - Brian D Cain
- Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, Florida, USA
| | - Peter P Sayeski
- Department of Physiology and Functional Genomics, University of Florida, Gainesville, Florida, USA
| | - Michelle L Gumz
- Division of Nephrology, Hypertension and Renal Transplantation, Department of Medicine, University of Florida, Gainesville, Florida, USA
- Department of Physiology and Functional Genomics, University of Florida, Gainesville, Florida, USA
- Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, Florida, USA
- Nephrology Section, Veteran Administration Medical Center, North Florida/South Georgia Malcom Randall Department of Veterans Affairs Medical Center, Gainesville, Florida, USA
| | - Charles S Wingo
- Division of Nephrology, Hypertension and Renal Transplantation, Department of Medicine, University of Florida, Gainesville, Florida, USA
- Department of Physiology and Functional Genomics, University of Florida, Gainesville, Florida, USA
- Nephrology Section, Veteran Administration Medical Center, North Florida/South Georgia Malcom Randall Department of Veterans Affairs Medical Center, Gainesville, Florida, USA
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Glomerular Mesangial Cell pH Homeostasis Mediates Mineralocorticoid Receptor-Induced Cell Proliferation. Biomedicines 2021; 9:biomedicines9091117. [PMID: 34572303 PMCID: PMC8468551 DOI: 10.3390/biomedicines9091117] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Revised: 08/24/2021] [Accepted: 08/27/2021] [Indexed: 11/17/2022] Open
Abstract
Mineralocorticoids (e.g., aldosterone) support chronic inflammatory tissue damage, including glomerular mesangial injury leading to glomerulosclerosis. Furthermore, aldosterone leads to activation of the extracellular signal-regulated kinases (ERK1/2) in rat glomerular mesangial cells (GMC). Because ERK1/2 can affect cellular pH homeostasis via activation of Na+/H+-exchange (NHE) and the resulting cellular alkalinization may support proliferation, we tested the hypothesis that aldosterone affects pH homeostasis and thereby cell proliferation as well as collagen secretion also in primary rat GMC. Cytoplasmic pH and calcium were assessed by single-cell fluorescence ratio imaging, using the dyes BCECF or FURA2, respectively. Proliferation was determined by cell counting, thymidine incorporation and collagen secretion by collagenase-sensitive proline incorporation and ERK1/2-phosphorylation by Western blot. Nanomolar aldosterone induces a rapid cytosolic alkalinization which is prevented by NHE inhibition (10 µmol/L EIPA) and by blockade of the mineralocorticoid receptor (100 nmol/L spironolactone). pH changes were not affected by inhibition of HCO3- transporters and were not dependent on HCO3-. Aldosterone enhanced ERK1/2 phosphorylation and inhibition of ERK1/2-phosphorylation (10 µmol/L U0126) prevented aldosterone-induced alkalinization. Furthermore, aldosterone induced proliferation of GMC and collagen secretion, both of which were prevented by U0126 and EIPA. Cytosolic calcium was not involved in this aldosterone action. In conclusion, our data show that aldosterone can induce GMC proliferation via a MR and ERK1/2-mediated activation of NHE with subsequent cytosolic alkalinization. GMC proliferation leads to glomerular hypercellularity and dysfunction. This effect presents a possible mechanism contributing to mineralocorticoid receptor-induced pathogenesis of glomerular mesangial injury during chronic kidney disease.
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Sweeney M, Corden B, Cook SA. Targeting cardiac fibrosis in heart failure with preserved ejection fraction: mirage or miracle? EMBO Mol Med 2020; 12:e10865. [PMID: 32955172 PMCID: PMC7539225 DOI: 10.15252/emmm.201910865] [Citation(s) in RCA: 100] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 07/30/2020] [Accepted: 08/14/2020] [Indexed: 12/11/2022] Open
Abstract
Cardiac fibrosis is central to the pathology of heart failure, particularly heart failure with preserved ejection fraction (HFpEF). Irrespective of the underlying profibrotic condition (e.g. ageing, diabetes, hypertension), maladaptive cardiac fibrosis is defined by the transformation of resident fibroblasts to matrix-secreting myofibroblasts. Numerous profibrotic factors have been identified at the molecular level (e.g. TGFβ, IL11, AngII), which activate gene expression programs for myofibroblast activation. A number of existing HF therapies indirectly target fibrotic pathways; however, despite multiple clinical trials in HFpEF, a specific clinically effective antifibrotic therapy remains elusive. Therapeutic inhibition of TGFβ, the master-regulator of fibrosis, has unfortunately proven toxic and ineffective in clinical trials to date, and new approaches are needed. In this review, we discuss the pathophysiology and clinical implications of interstitial fibrosis in HFpEF. We provide an overview of trials targeting fibrosis in HFpEF to date and discuss the promise of potential new therapeutic approaches and targets in the context of underlying molecular mechanisms.
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Affiliation(s)
- Mark Sweeney
- MRC‐London Institute of Medical SciencesHammersmith Hospital CampusLondonUK
- Wellcome Trust 4i/NIHR Clinical Research FellowImperial CollegeLondonUK
| | - Ben Corden
- MRC‐London Institute of Medical SciencesHammersmith Hospital CampusLondonUK
- National Heart Research Institute SingaporeNational Heart Centre SingaporeSingaporeSingapore
- Cardiovascular and Metabolic Disorders ProgramDuke‐National University of Singapore Medical SchoolSingaporeSingapore
- National Heart and Lung InstituteImperial College LondonLondonUK
| | - Stuart A Cook
- MRC‐London Institute of Medical SciencesHammersmith Hospital CampusLondonUK
- National Heart Research Institute SingaporeNational Heart Centre SingaporeSingaporeSingapore
- Cardiovascular and Metabolic Disorders ProgramDuke‐National University of Singapore Medical SchoolSingaporeSingapore
- National Heart and Lung InstituteImperial College LondonLondonUK
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Young MJ, Adler GK. Aldosterone, the Mineralocorticoid Receptor and Mechanisms of Cardiovascular Disease. VITAMINS AND HORMONES 2019; 109:361-385. [DOI: 10.1016/bs.vh.2018.10.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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Aldosterone and Mineralocorticoid Receptor System in Cardiovascular Physiology and Pathophysiology. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2018; 2018:1204598. [PMID: 30327709 PMCID: PMC6169243 DOI: 10.1155/2018/1204598] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Revised: 08/14/2018] [Accepted: 08/16/2018] [Indexed: 12/22/2022]
Abstract
The mineralocorticoid hormone aldosterone (Aldo) has been intensively studied for its ability to influence both the physiology and pathophysiology of the cardiovascular system. Indeed, although research on Aldo actions for decades has mainly focused on its effects in the kidney, several lines of evidence have now demonstrated that this hormone exerts disparate extrarenal adverse effects, especially in the circulatory system. Accordingly, in the last lusters, a number of studies in preclinical models (in vitro and in vivo) and in humans have established that Aldo, following the interaction with its receptor-the mineralocorticoid receptor (MR)-is able to activate specific intracellular genomic and nongenomic pathways, thus regulating the homeostasis of the cardiovascular system. Importantly, through this mechanism of action, this hormone becomes a crucial regulator of the function and growth of different types of cells, including fibroblasts, cardiomyocytes, and vascular cells. For this main reason, it is plausible that when Aldo is present at high levels in the blood, it profoundly modifies the physiology of these cells, therefore being at the foundation of several cardiovascular disorders, such as heart failure (HF). On these grounds, in this review, we will provide an updated account on the current knowledge concerning Aldo activity in the cardiovascular system and the most recent preclinical studies and clinical trials designed to test better approaches able to counter the hyperactivity of the Aldo/MR signaling pathway in the setting of cardiovascular diseases.
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Leite-Dellova DCA, Szriber SJ, Merighe GKF, Polidoro JZ, Rebouças NA, Oliveira-Souza M, de Mello-Aires M. Signaling pathways involved in the rapid biphasic effect of aldosterone on Na +/H + exchanger in rat proximal tubule cells. J Steroid Biochem Mol Biol 2018; 182:87-94. [PMID: 29702262 DOI: 10.1016/j.jsbmb.2018.04.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Revised: 04/21/2018] [Accepted: 04/23/2018] [Indexed: 10/17/2022]
Abstract
The receptors and signaling pathways for nongenomic effects of aldosterone (Aldo) on the proximal Na+/H+ exchanger are still unknown; therefore, the aim of this study was to investigate the mineralocorticoid receptor (MR) and/or glucocorticoid receptor (GR) participation in rapid Aldo effects on NHE1 (basolateral Na+/H+ exchanger isoform) and cytosolic calcium concentration ([Ca2+]i). In addition, phospholipase C (PLC), protein kinase C (PKC), and mitogen-activated protein kinase kinase (MEK) involvement in signaling pathways of such effects was evaluated, using immortalized proximal tubule cells of rat (IRPTC) as an experimental model. MR and GR expression was investigated using reverse transcription polymerase chain reaction and immunoblotting. The intracellular pH recovery rate (after acid loading) and [Ca2+]i were determined by the probes BCECF-AM and FURA 2-AM, respectively. Aldo (10-12 M) promoted a moderate increase in [Ca2+]i and stimulation of NHE1, whereas Aldo (10-6 M) greatly increased the [Ca2+]i, but inhibited the NHE1. BAPTA-AM (a calcium chelator), GR antagonism and inhibition of PLC, PKC and MEK pathway abolished the biphasic and dose-dependent effect of Aldo on NHE1 and decreased the [Ca2+]i; whereas MR do not appear to participate in this rapid signaling in IRPTC cells. The reduction of GR content, by gene silencing, abolished the Aldo effect on NHE1, in low concentration, confirming the importance of this receptor in the rapid modulation of proximal sodium and hydrogen transports.
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Affiliation(s)
- Deise C A Leite-Dellova
- Department of Veterinary Medicine, Faculty of Animal Science and Food Engineering, University of Sao Paulo, Pirassununga, Brazil.
| | - Shirley J Szriber
- Department of Veterinary Medicine, Faculty of Animal Science and Food Engineering, University of Sao Paulo, Pirassununga, Brazil
| | - Giovana K F Merighe
- Basic Sciences, Faculty of Animal Science and Food Engineering, University of Sao Paulo, Pirassununga, Brazil
| | - Juliano Z Polidoro
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, Brazil
| | - Nancy A Rebouças
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, Brazil
| | - Maria Oliveira-Souza
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, Brazil
| | - Margarida de Mello-Aires
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, Brazil
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Harvey BJ, Thomas W. Aldosterone-induced protein kinase signalling and the control of electrolyte balance. Steroids 2018; 133:67-74. [PMID: 29079406 DOI: 10.1016/j.steroids.2017.10.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Revised: 10/18/2017] [Accepted: 10/21/2017] [Indexed: 01/20/2023]
Abstract
Aldosterone acts through the mineralocorticoid receptor (MR) to modulate gene expression in target tissues. In the kidney, the principal action of aldosterone is to promote sodium conservation in the distal nephron and so indirectly enhance water conservation under conditions of hypotension. Over the last twenty years the rapid activation of protein kinase signalling cascades by aldosterone has been described in various tissues. This review describes the integration of rapid protein kinase D signalling responses with the non-genomic actions of aldosterone and transcriptional effects of MR activation.
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Affiliation(s)
- Brian J Harvey
- Molecular Medicine Laboratories, Royal College of Surgeons in Ireland, Education Centre, Beaumont Hospital, Dublin, Ireland
| | - Warren Thomas
- Molecular Medicine Laboratories, Royal College of Surgeons in Ireland, Education Centre, Beaumont Hospital, Dublin, Ireland; Perdana University - Royal College of Surgeons in Ireland School of Medicine, Serdang, Selangor, Malaysia.
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Hermidorff MM, de Assis LVM, Isoldi MC. Genomic and rapid effects of aldosterone: what we know and do not know thus far. Heart Fail Rev 2018; 22:65-89. [PMID: 27942913 DOI: 10.1007/s10741-016-9591-2] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Aldosterone is the most known mineralocorticoid hormone synthesized by the adrenal cortex. The genomic pathway displayed by aldosterone is attributed to the mineralocorticoid receptor (MR) signaling. Even though the rapid effects displayed by aldosterone are long known, our knowledge regarding the receptor responsible for such event is still poor. It is intense that the debate whether the MR or another receptor-the "unknown receptor"-is the receptor responsible for the rapid effects of aldosterone. Recently, G protein-coupled estrogen receptor-1 (GPER-1) was elegantly shown to mediate some aldosterone-induced rapid effects in several tissues, a fact that strongly places GPER-1 as the unknown receptor. It has also been suggested that angiotensin receptor type 1 (AT1) also participates in the aldosterone-induced rapid effects. Despite this open question, the relevance of the beneficial effects of aldosterone is clear in the kidneys, colon, and CNS as aldosterone controls the important water reabsorption process; on the other hand, detrimental effects displayed by aldosterone have been reported in the cardiovascular system and in the kidneys. In this line, the MR antagonists are well-known drugs that display beneficial effects in patients with heart failure and hypertension; it has been proposed that MR antagonists could also play an important role in vascular disease, obesity, obesity-related hypertension, and metabolic syndrome. Taken altogether, our goal here was to (1) bring a historical perspective of both genomic and rapid effects of aldosterone in several tissues, and the receptors and signaling pathways involved in such processes; and (2) critically address the controversial points within the literature as regarding which receptor participates in the rapid pathway display by aldosterone.
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Affiliation(s)
- Milla Marques Hermidorff
- Laboratory of Hypertension, Research Center in Biological Science, Institute of Exact and Biological Sciences, Federal University of Ouro Preto, Campus Morro do Cruzeiro, Ouro Preto, MG, 35400-000, Brazil
| | - Leonardo Vinícius Monteiro de Assis
- Laboratory of Comparative Physiology of Pigmentation, Department of Physiology, Institute of Biosciences, University of São Paulo, São Paulo, Brazil
| | - Mauro César Isoldi
- Laboratory of Hypertension, Research Center in Biological Science, Institute of Exact and Biological Sciences, Federal University of Ouro Preto, Campus Morro do Cruzeiro, Ouro Preto, MG, 35400-000, Brazil.
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Protein mediated regulation of the NHE1 isoform of the Na + /H + exchanger in renal cells. A regulatory role of Hsp90 and AKT kinase. Cell Signal 2017; 36:145-153. [DOI: 10.1016/j.cellsig.2017.05.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Revised: 04/28/2017] [Accepted: 05/05/2017] [Indexed: 11/19/2022]
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Ruhs S, Nolze A, Hübschmann R, Grossmann C. 30 YEARS OF THE MINERALOCORTICOID RECEPTOR: Nongenomic effects via the mineralocorticoid receptor. J Endocrinol 2017; 234:T107-T124. [PMID: 28348113 DOI: 10.1530/joe-16-0659] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Accepted: 03/27/2017] [Indexed: 12/12/2022]
Abstract
The mineralocorticoid receptor (MR) belongs to the steroid hormone receptor family and classically functions as a ligand-dependent transcription factor. It is involved in water-electrolyte homeostasis and blood pressure regulation but independent from these effects also furthers inflammation, fibrosis, hypertrophy and remodeling in cardiovascular tissues. Next to genomic effects, aldosterone elicits very rapid actions within minutes that do not require transcription or translation and that occur not only in classical MR epithelial target organs like kidney and colon but also in nonepithelial tissues like heart, vasculature and adipose tissue. Most of these effects can be mediated by classical MR and its crosstalk with different signaling cascades. Near the plasma membrane, the MR seems to be associated with caveolin and striatin as well as with receptor tyrosine kinases like EGFR, PDGFR and IGF1R and G protein-coupled receptors like AT1 and GPER1, which then mediate nongenomic aldosterone effects. GPER1 has also been named a putative novel MR. There is a close interaction and functional synergism between the genomic and the nongenomic signaling so that nongenomic signaling can lead to long-term effects and support genomic actions. Therefore, understanding nongenomic aldosterone/MR effects is of potential relevance for modulating genomic aldosterone effects and may provide additional targets for intervention.
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Affiliation(s)
- Stefanie Ruhs
- Julius Bernstein Institute of PhysiologyMartin Luther University Halle-Wittenberg, Halle, Germany
| | - Alexander Nolze
- Julius Bernstein Institute of PhysiologyMartin Luther University Halle-Wittenberg, Halle, Germany
| | - Ralf Hübschmann
- Julius Bernstein Institute of PhysiologyMartin Luther University Halle-Wittenberg, Halle, Germany
| | - Claudia Grossmann
- Julius Bernstein Institute of PhysiologyMartin Luther University Halle-Wittenberg, Halle, Germany
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Eiam-Ong S, Chaipipat M, Manotham K, Eiam-Ong S. Rapid Action of Aldosterone on Protein Levels of Sodium-Hydrogen Exchangers and Protein Kinase C Beta Isoforms in Rat Kidney. Int J Endocrinol 2017; 2017:2975853. [PMID: 29201052 PMCID: PMC5671724 DOI: 10.1155/2017/2975853] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Revised: 06/23/2017] [Accepted: 08/06/2017] [Indexed: 12/22/2022] Open
Abstract
Previous in vitro studies demonstrated that aldosterone rapidly activates sodium-hydrogen exchangers 1 and 3 (NHE 1 and 3). In vitro investigations revealed that protein kinase C (PKC) regulates NHE properties. We previously demonstrated that aldosterone rapidly enhances PKCα protein abundance in the rat kidney. There are no reports of renal PKCβ (I and II) protein levels related to the regulation by aldosterone. There are also no in vivo data regarding the rapid effects of aldosterone on renal protein levels of NHE (1 and 3) and PKCβ (I and II), simultaneously. In the current study, rats received normal saline solution or aldosterone (150 μg/kg BW, i.p.). After 30 minutes, abundance and immunoreactivity of these proteins were determined by Western blot analysis and immunohistochemistry, respectively. Aldosterone increased NHE1 and NHE3 protein abundance to 152% and 134%, respectively (P < 0.05). PKCβI protein level was enhanced by 30%, whereas PKCβII declined slightly. Aldosterone increased NHE protein expression mostly in the medulla. PKCβI immunostaining intensity was increased in the glomeruli, renal vasculature, and thin limb of the loop of Henle, while PKCβII was reduced. This is the first in vivo study to simultaneously demonstrate that aldosterone rapidly elevates PKCβI and NHE (1 and 3) protein abundance in the rat kidney. Aldosterone-induced NHE (1 and 3) protein levels may be related to PKCβI activation.
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Affiliation(s)
- Somchit Eiam-Ong
- Department of Physiology, Faculty of Medicine, Chulalongkorn University, Bangkok 10330, Thailand
| | - Mookda Chaipipat
- Department of Pathology, Faculty of Medicine, Chulalongkorn University, Bangkok 10330, Thailand
| | | | - Somchai Eiam-Ong
- Department of Medicine (Division of Nephrology), Faculty of Medicine, Chulalongkorn University, Bangkok 10330, Thailand
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Ren Y, Janic B, Kutskill K, Peterson EL, Carretero OA. Mechanisms of connecting tubule glomerular feedback enhancement by aldosterone. Am J Physiol Renal Physiol 2016; 311:F1182-F1188. [PMID: 27413197 DOI: 10.1152/ajprenal.00076.2016] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Accepted: 07/08/2016] [Indexed: 11/22/2022] Open
Abstract
Connecting tubule glomerular feedback (CTGF) is a mechanism where an increase in sodium (Na) concentration in the connecting tubule (CNT) causes the afferent arteriole (Af-Art) to dilate. We recently reported that aldosterone within the CNT lumen enhances CTGF via a nongenomic effect involving GPR30 receptors and sodium/hydrogen exchanger (NHE), but the signaling pathways of this mechanism are unknown. We hypothesize that aldosterone enhances CTGF via cAMP/protein kinase A (PKA) pathway that activates protein kinase C (PKC) and stimulates superoxide (O2-) production. Rabbit Af-Arts and their adherent CNTs were microdissected and simultaneously perfused. Two consecutive CTGF curves were elicited by increasing the CNT luminal NaCl. We found that the main effect of aldosterone was to sensitize CTGF and we analyzed data by comparing NaCl concentration in the CNT perfusate needed to achieve half of the maximal response (EC50). During the control period, the NaCl concentration that elicited a half-maximal response (EC50) was 37.0 ± 2.0 mmol/l; addition of aldosterone (10-8 mol/l) to the CNT lumen decreased EC50 to 19.3 ± 1.3 mmol/l (P ≤ 0.001 vs. Control). The specific adenylyl cyclase inhibitor 2',3'-dideoxyadenosine (ddA; 2 × 10-4 mol/l) and the PKA inhibitor H-89 dihydrochloride hydrate (H-89; 2 × 10-6 mol/l) prevented the aldosterone effect. The selective PKC inhibitor GF109203X (10-8 mol/l) also prevented EC50 reduction caused by aldosterone. CNT intraluminal addition of O2- scavenger tempol (10-4 mol/l) blocked the aldosterone effect. We conclude that aldosterone inside the CNT lumen enhances CTGF via a cAMP/PKA/PKC pathway and stimulates O2- generation and this process may contribute to renal damage by increasing glomerular capillary pressure.
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Affiliation(s)
- YiLin Ren
- Hypertension and Vascular Research Division, Department of Internal Medicine, Henry Ford Hospital, Detroit, Michigan; and
| | - Branislava Janic
- Hypertension and Vascular Research Division, Department of Internal Medicine, Henry Ford Hospital, Detroit, Michigan; and
| | - Kristopher Kutskill
- Hypertension and Vascular Research Division, Department of Internal Medicine, Henry Ford Hospital, Detroit, Michigan; and
| | - Edward L Peterson
- Department of Public Health Sciences, Henry Ford Hospital, Detroit, Michigan
| | - Oscar A Carretero
- Hypertension and Vascular Research Division, Department of Internal Medicine, Henry Ford Hospital, Detroit, Michigan; and
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Carreño JE, Verdugo FJ, Contreras F, Montellano FA, Veloso S, Schalper KA, Sandoval M, Villanueva S, Marusic E, Irarrazabal CE. Spironolactone inhibits the activity of the Na+/H+exchanger in the aorta of mineralocorticoid-induced hypertensive rats. J Renin Angiotensin Aldosterone Syst 2015; 16:1225-31. [DOI: 10.1177/1470320315587193] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2015] [Accepted: 03/24/2015] [Indexed: 11/17/2022] Open
Affiliation(s)
- Juan E Carreño
- Laboratory of Molecular Physiology, Faculty of Medicine, Universidad de los Andes, Chile
| | - Fernando J Verdugo
- Laboratory of Molecular Physiology, Faculty of Medicine, Universidad de los Andes, Chile
| | - Felipe Contreras
- Laboratory of Molecular Physiology, Faculty of Medicine, Universidad de los Andes, Chile
| | - Felipe A Montellano
- Laboratory of Molecular Physiology, Faculty of Medicine, Universidad de los Andes, Chile
| | - Sebastian Veloso
- Laboratory of Molecular Physiology, Faculty of Medicine, Universidad de los Andes, Chile
| | | | - Mauricio Sandoval
- Laboratory of Molecular Physiology, Faculty of Medicine, Universidad de los Andes, Chile
| | - Sandra Villanueva
- Laboratory of Molecular Physiology, Faculty of Medicine, Universidad de los Andes, Chile
| | - Elisa Marusic
- Laboratory of Molecular Physiology, Faculty of Medicine, Universidad de los Andes, Chile
| | - Carlos E Irarrazabal
- Laboratory of Molecular Physiology, Faculty of Medicine, Universidad de los Andes, Chile
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Jin W, Lu Y, Li Q, Wang J, Zhang H, Chang G, Lin Y, Pang T. Down-regulation of the P-glycoprotein relevant for multidrug resistance by intracellular acidification through the crosstalk of MAPK signaling pathways. Int J Biochem Cell Biol 2014; 54:111-21. [DOI: 10.1016/j.biocel.2014.06.016] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2013] [Revised: 05/07/2014] [Accepted: 06/22/2014] [Indexed: 01/20/2023]
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Abstract
Aldosterone regulates blood pressure through its effects on the kidney and the cardiovascular system. Dysregulation of aldosterone signalling can result in hypertension which in turn can lead to chronic pathologies of the kidney such as renal fibrosis and nephropathy. Aldosterone acts by binding to the mineralocorticoid receptor (MR), which acts as a ligand-dependent transcription factor in target tissues such as segments of the distal nephron including the connecting tubule and cortical collecting duct (CCD). Aldosterone also promotes the activation of protein kinase signalling cascades that are coupled to growth factor receptors and act directly on specific substrates in the cell membrane or cytoplasm. The rapid actions of aldosterone can also modulate gene expression through the phosphorylation of transcription factors. Aldosterone is a key regulator of Na(+) conservation in the distal nephron, largely through multiple mechanisms that modulate the activity of the epithelial Na(+) channel (ENaC). Aldosterone transcriptionally up-regulates the ENaCα subunit and also up regulates serum and glucocorticoid-regulated kinase-1 (SGK1) that indirectly regulates the ubiquitination of ENaC subunits. Aldosterone promotes the activation of protein kinase D1 (PKD1) which can modify the activity of ENaC and other transporters through effects on sub-cellular trafficking. In M1-CCD cells, early sub-cellular trafficking causes the redistribution of ENaC subunits within minutes of treatment with aldosterone. ENaC subunits can also interact directly with phosphatidylinositide signalling intermediates in the membrane and the mechanism by which PKD isoforms regulate protein trafficking is through the control of vesicle fission from the trans Golgi network by activation of phosphatidylinositol 4-kinaseIIIβ (PI4KIIIβ).
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Affiliation(s)
- Sinéad Quinn
- Molecular Medicine Laboratories, Royal College of Surgeons in Ireland, Education and Research Centre, Beaumont Hospital, Dublin 9, Ireland
| | - Brian J Harvey
- Molecular Medicine Laboratories, Royal College of Surgeons in Ireland, Education and Research Centre, Beaumont Hospital, Dublin 9, Ireland
| | - Warren Thomas
- Molecular Medicine Laboratories, Royal College of Surgeons in Ireland, Education and Research Centre, Beaumont Hospital, Dublin 9, Ireland.
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Abstract
PURPOSE OF REVIEW Aldosterone is now recognized as an increasingly important contributor to cardiometabolic pathology via inflammatory and fibrosis-related pathways in addition to its classically described role in sodium and volume regulation. Consequently, much effort has been directed towards characterizing the molecular pathways involved in aldosterone-mediated fibrosis and inflammation. What was once viewed as straightforward steroid hormone biology is now appreciated as a highly complex and tightly regulated series of pathways and interactions. These recognitions have fuelled a multidisciplinary effort to identify precisely how aldosterone mediates intracellular activation of both genomic (latent) and nongenomic (rapid) mechanisms of influence. This review will explore recent novel pathways regulating aldosterone action, focusing on the nongenomic pathways. RECENT FINDINGS Several recent discoveries have redefined our understanding of aldosterone interactions at the cellular level. This includes activation of the mineralocorticoid receptor at the plasma membrane instead of via classical nuclear hormone receptor interaction, and identification of novel cofactor scaffolding proteins that modify aldosterone influence at the cellular level. In addition, aldosterone activation of secondary messenger system cascades can occur directly and independent of mineralocorticoid receptor interaction. SUMMARY Substantial progress in detailing the molecular biology of aldosterone regulation and action should facilitate study of how it exerts detrimental effects in cardiometabolic diseases. However, to date, the clinical impact of these discoveries has not been validated. Translational efforts are now required to determine if novel therapeutic targets can be developed.
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Affiliation(s)
- Jonathan S Williams
- Division of Endocrinology, Diabetes and Hypertension, Brigham and Women's Hospital/Harvard Medical School, Boston, MA 02115, USA.
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18
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Odunewu A, Fliegel L. Acidosis-mediated regulation of the NHE1 isoform of the Na⁺/H⁺ exchanger in renal cells. Am J Physiol Renal Physiol 2013; 305:F370-81. [PMID: 23678047 DOI: 10.1152/ajprenal.00598.2012] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The mammalian Na⁺/H⁺ exchanger isoform 1 (NHE1) is a ubiquitous plasma membrane protein that regulates intracellular pH by removing a proton in exchange for extracellular sodium. Renal tissues are subject to metabolic and respiratory acidosis, and acidosis has been shown to acutely activate NHE1 activity in other cell types. We examined if NHE1 is activated by acute acidosis in HEK293 and Madin-Darby canine kidney (MDCK) cells. Acute sustained intracellular acidosis (SIA) activated NHE1 in both cell types. We expressed wild-type and mutant NHE1 cDNAs in MDCK cells. All the cDNAs had a L163F/G174S mutation, which conferred a 100-fold resistance to EMD87580, an NHE1-specific inhibitor. We assayed exogenous NHE1 activity while inhibiting endogenous activity with EMD87580 and while inhibiting the NHE3 isoform of the Na⁺/H⁺ exchanger using the isoform-specific inhibitor S3226. We examined the activation and phosphorylation of the wild-type and mutant NHE1 proteins in response to SIA. In MDCK cells we demonstrated that the amino acids Ser⁷⁷¹, Ser⁷⁷⁶, Thr⁷⁷⁹, and Ser⁷⁸⁵ are important for NHE1 phosphorylation and activation after acute SIA. SIA activated ERK-dependent pathways in MDCK cells, and this was blocked by treatment with the MEK inhibitor U0126. Treatment with U0126 also blocked activation of NHE1 by SIA. These results suggest that acute acidosis activates NHE1 in mammalian kidney cells and that in MDCK cells this activation occurs through an ERK-dependent pathway affecting phosphorylation of a distinct set of amino acids in the cytosolic regulatory tail of NHE1.
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Affiliation(s)
- Ayodeji Odunewu
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada
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19
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Pelzl L, Pakladok T, Pathare G, Fakhri H, Michael D, Wagner CA, Paulmichl M, Lang F. DOCA sensitive pendrin expression in kidney, heart, lung and thyroid tissues. Cell Physiol Biochem 2012; 30:1491-501. [PMID: 23235354 DOI: 10.1159/000343337] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/23/2012] [Indexed: 01/12/2023] Open
Abstract
BACKGROUND/AIMS Pendrin (SLC26A4), a transporter accomplishing anion exchange, is expressed in inner ear, thyroid gland, kidneys, lung, liver and heart. Loss or reduction of function mutations of SLC26A4 underlie Pendred syndrome, a disorder invariably leading to hearing loss with enlarged vestibular aqueducts and in some patients to hypothyroidism and goiter. Renal pendrin expression is up-regulated by mineralocorticoids such as aldosterone or deoxycorticosterone (DOCA). Little is known about the impact of mineralocorticoids on pendrin expression in extrarenal tissues. METHODS The present study utilized RT-qPCR and Western blotting to quantify the transcript levels and protein abundance of Slc26a4 in murine kidney, thyroid, heart and lung prior to and following subcutaneous administration of 100 mg/kg DOCA. RESULTS Slc26a4 transcript levels as compared to Gapdh transcript levels were significantly increased by DOCA treatment in kidney, heart, lung and thyroid. Accordingly pendrin protein expression was again significantly increased by DOCA treatment in kidney, heart, lung and thyroid. CONCLUSION The observations reveal mineralocorticoid sensitivity of pendrin expression in kidney, heart, thyroid and lung.
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Affiliation(s)
- Lisann Pelzl
- Department of Physiology, University of Tuebingen, Tuebingen, Germany
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20
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Dooley R, Harvey BJ, Thomas W. Non-genomic actions of aldosterone: from receptors and signals to membrane targets. Mol Cell Endocrinol 2012; 350:223-34. [PMID: 21801805 DOI: 10.1016/j.mce.2011.07.019] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/25/2011] [Revised: 07/05/2011] [Accepted: 07/09/2011] [Indexed: 10/17/2022]
Abstract
In tissues which express the mineralocorticoid receptor (MR), aldosterone modulates the expression of membrane targets such as the subunits of the epithelial Na(+) channel, in combination with important signalling intermediates such as serum and glucocorticoid-regulated kinase-1. In addition, the rapid 'non-genomic' activation of protein kinases and secondary messenger signalling cascades has also been detected in aldosterone-sensitive tissues of the nephron, distal colon and cardiovascular system. These rapid actions are variously described as being coupled to MR or to an as yet unidentified, membrane-associated aldosterone receptor. The rapidly activated signalling cascades add a level of fine-tuning to the activity of aldosterone-responsive membrane transporters and also modulate the aldosterone-induced changes in gene expression through receptor and transcription factor phosphorylation.
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Affiliation(s)
- Ruth Dooley
- Department of Molecular Medicine, Royal College of Surgeons in Ireland, Education and Research Centre, Beaumont Hospital, Dublin 9, Ireland
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21
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Braga-Sobrinho C, Leite-Dellova DCA, Mello-Aires M. Action of ANP on the nongenomic dose-dependent biphasic effect of aldosterone on NHE1 in proximal S3 segment. J Steroid Biochem Mol Biol 2012; 128:89-97. [PMID: 22154810 DOI: 10.1016/j.jsbmb.2011.11.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2011] [Revised: 11/18/2011] [Accepted: 11/19/2011] [Indexed: 10/15/2022]
Abstract
The rapid (2 min) nongenomic effects of aldosterone (ALDO) and/or spironolactone (MR antagonist), RU 486 (GR antagonist), atrial natriuretic peptide (ANP) and dimethyl-BAPTA (BAPTA) on the intracellular pH recovery rate (pHirr) via NHE1 (basolateral Na⁺/H⁺ exchanger isoform), after the acid load induced by NH₄Cl, and on the cytosolic free calcium concentration ([Ca²⁺](i)) were investigated in the proximal S3 segment isolated from rats, by the probes BCECF-AM and FLUO-4-AM, respectively. The basal pHi was 7.15±0.008 and the basal pHirr was 0.195±0.012 pH units/min (number of tubules/number of tubular areas=16/96). Our results confirmed the rapid biphasic effect of ALDO on NHE1: ALDO (10⁻¹² M) increases the pHirr to approximately 59% of control value, and ALDO (10⁻⁶ M) decreases it to approximately 49%. Spironolactone did not change these effects, but RU 486 inhibited the stimulatory effect and maintained the inhibitory effect. ANP (10⁻⁶ M) or BAPTA (5×10⁻⁵ M) alone had no significant effect on NHE1 but prevented both effects of ALDO on this exchanger. The basal [Ca²⁺](i) was 104±3 nM (15), and ALDO (10⁻¹² or 10⁻⁶ M) increased the basal [Ca²⁺](i) to approximately 50% or 124%, respectively. RU 486, ANP and BAPTA decreased the [Ca²⁺](i) and inhibited the stimulatory effect of both doses of ALDO. The results suggest the involvement of GR on the nongenomic effects of ALDO and indicate a pHirr-regulating role for [Ca²⁺](i) that is mediated by NHE1, stimulated/impaired by ALDO, and affected by ANP or BAPTA with ALDO. The observed nongenomic hormonal interaction in the S3 segment may represent a rapid and physiologically relevant regulatory mechanism in the intact animal under conditions of volume alterations.
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Affiliation(s)
- C Braga-Sobrinho
- Department of Physiology and Biophysics, Instituto de Ciências Biomédicas, University of São Paulo, Av. Prof. Lineu Prestes, 1524, Cidade Universitária, 05508-900 SP, Brazil
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22
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Muthusamy S, Shukla S, Amin MR, Cheng M, Orenuga T, Dudeja PK, Malakooti J. PKCδ-dependent activation of ERK1/2 leads to upregulation of the human NHE2 transcriptional activity in intestinal epithelial cell line C2BBe1. Am J Physiol Gastrointest Liver Physiol 2012; 302:G317-25. [PMID: 22052014 PMCID: PMC3287399 DOI: 10.1152/ajpgi.00363.2011] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The apical Na+/H+ exchanger (NHE) isoform NHE2 is involved in transepithelial Na+ absorption in the intestine. Our earlier studies have shown that mitogenic agent phorbol 12-myristate 13-acetate (PMA) induces the expression of NHE2 through activation of transcription factor early growth response-1 (Egr-1) and its interactions with the NHE2 promoter. However, the signaling pathways involved in transcriptional stimulation of NHE2 in response to PMA in the intestinal epithelial cells are not known. Chemical inhibitors and genetic approaches were used to investigate the signaling pathways responsible for the stimulation of NHE2 expression by PMA via Egr-1 induction. We show that, in response to PMA, PKCδ, a member of novel PKC isozymes, and MEK-ERK1/2 pathway of mitogen-activated protein kinases stimulate the NHE2 expression in C2BBe1 intestinal epithelial cells. PMA rapidly and transiently induced activation of PKCδ. Small inhibitory RNA-mediated knockdown of PKCδ blocked the stimulatory effect of PMA on the NHE2 promoter activity. In addition, blockade of PKCδ by rottlerin, a PKCδ-specific inhibitor, and ERK1/2 by U0126, a MEK-ERK inhibitor, abrogated PMA-induced Egr-1 expression. Immunofluorescence studies revealed that inhibition of ERK1/2 activation prevents translocation of PMA-induced Egr-1 into the nucleus. Consistent with these data, PMA-induced Egr-1 interaction with the NHE2 promoter region was prevented in nuclear extracts from U0126-pretreated cells. In conclusion, our data provide the first evidence that the stimulatory effect of PMA on NHE2 expression is mediated through the initial activation of PKCδ, subsequent PKCδ-dependent activation of MEK-ERK1/2 signaling pathway, and stimulation of Egr-1 expression. Furthermore, we show that transcription factor Egr-1 acts as an intermediate effector molecule that links the upstream signaling cues to the long-term stimulation of NHE2 expression by PMA in C2BBe1 cells.
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Affiliation(s)
- Saminathan Muthusamy
- Section of Digestive Diseases and Nutrition, Department of Medicine, University of Illinois at Chicago, Chicago, Illinois
| | - Sagar Shukla
- Section of Digestive Diseases and Nutrition, Department of Medicine, University of Illinois at Chicago, Chicago, Illinois
| | - Md. Ruhul Amin
- Section of Digestive Diseases and Nutrition, Department of Medicine, University of Illinois at Chicago, Chicago, Illinois
| | - Ming Cheng
- Section of Digestive Diseases and Nutrition, Department of Medicine, University of Illinois at Chicago, Chicago, Illinois
| | - Temitope Orenuga
- Section of Digestive Diseases and Nutrition, Department of Medicine, University of Illinois at Chicago, Chicago, Illinois
| | - Pradeep K. Dudeja
- Section of Digestive Diseases and Nutrition, Department of Medicine, University of Illinois at Chicago, Chicago, Illinois
| | - Jaleh Malakooti
- Section of Digestive Diseases and Nutrition, Department of Medicine, University of Illinois at Chicago, Chicago, Illinois
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23
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Winter C, Kampik NB, Vedovelli L, Rothenberger F, Paunescu TG, Stehberger PA, Brown D, John H, Wagner CA. Aldosterone stimulates vacuolar H(+)-ATPase activity in renal acid-secretory intercalated cells mainly via a protein kinase C-dependent pathway. Am J Physiol Cell Physiol 2011; 301:C1251-61. [PMID: 21832245 DOI: 10.1152/ajpcell.00076.2011] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Urinary acidification in the collecting duct is mediated by the activity of H(+)-ATPases and is stimulated by various factors including angiotensin II and aldosterone. Classically, aldosterone effects are mediated via the mineralocorticoid receptor. Recently, we demonstrated a nongenomic stimulatory effect of aldosterone on H(+)-ATPase activity in acid-secretory intercalated cells of isolated mouse outer medullary collecting ducts (OMCD). Here we investigated the intracellular signaling cascade mediating this stimulatory effect. Aldosterone stimulated H(+)-ATPase activity in isolated mouse and human OMCDs. This effect was blocked by suramin, a general G protein inhibitor, and GP-2A, a specific G(αq) inhibitor, whereas pertussis toxin was without effect. Inhibition of phospholipase C with U-73122, chelation of intracellular Ca(2+) with BAPTA, and blockade of protein kinase C prevented the stimulation of H(+)-ATPases. Stimulation of PKC by DOG mimicked the effect of aldosterone on H(+)-ATPase activity. Similarly, aldosterone and DOG induced a rapid translocation of H(+)-ATPases to the luminal side of OMCD cells in vivo. In addition, PD098059, an inhibitor of ERK1/2 activation, blocked the aldosterone and DOG effects. Inhibition of PKA with H89 or KT2750 prevented and incubation with 8-bromoadenosine-cAMP mildly increased H(+)-ATPase activity. Thus, the nongenomic modulation of H(+)-ATPase activity in OMCD-intercalated cells by aldosterone involves several intracellular pathways and may be mediated by a G(αq) protein-coupled receptor and PKC. PKA and cAMP appear to have a modulatory effect. The rapid nongenomic action of aldosterone may participate in the regulation of H(+)-ATPase activity and contribute to final urinary acidification.
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Affiliation(s)
- Christian Winter
- Institute of Physiology, Center for Integrative Human Physiology, University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich Switzerland
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24
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Abstract
The steroid hormone aldosterone is a key regulator of electrolyte transport in the kidney and contributes to both homeostatic whole-body electrolyte balance and the development of renal and cardiovascular pathologies. Aldosterone exerts its action principally through the mineralocorticoid receptor (MR), which acts as a ligand-dependent transcription factor in target tissues. Aldosterone also stimulates the activation of protein kinases and secondary messenger signaling cascades that act independently on specific molecular targets in the cell membrane and also modulate the transcriptional action of aldosterone through MR. This review describes current knowledge regarding the mechanisms and targets of rapid aldosterone action in the nephron and how aldosterone integrates these responses into the regulation of renal physiology.
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Affiliation(s)
- Warren Thomas
- Department of Molecular Medicine, Royal College of Surgeons in Ireland, Beaumont Hospital, Dublin, Ireland.
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25
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Moriyama M, Jayakumar AR, Tong XY, Norenberg MD. Role of mitogen-activated protein kinases in the mechanism of oxidant-induced cell swelling in cultured astrocytes. J Neurosci Res 2010; 88:2450-8. [PMID: 20623534 DOI: 10.1002/jnr.22400] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Cytotoxic brain edema, usually a consequence of astrocyte swelling, is an important complication of stroke, traumatic brain injury, hepatic encephalopathy, and other neurological disorders. Although mechanisms underlying astrocyte swelling are not fully understood, oxidative stress (OS) has generally been considered an important factor in its pathogenesis. To better understand the mechanism(s) by which OS causes cell swelling, we examined the potential involvement of mitogen-activated protein kinases (MAPKs) in this process. Cultures exposed to theoxidant H(2)O(2) (10, 25, 50 microM) for different time periods (1-24 hr) significantly increased cell swelling in a triphasic manner. Swelling was initially observed at 10 min (peaking at 30 min), which was followed by cell shrinkage at 1 hr. A subsequent increase in cell volume occurred at approximately 6 hr, and the rise lasted for at least 24 hr. Cultures exposed to H(2)O(2) caused the activation of MAPKs (ERK1/2, JNK and p38-MAPK), whereas inhibition of MAPKs diminished cell swelling induced by 10 and 25 microM H(2)O(2). These findings suggest that activation of MAPKs is an important factor in the mediation of astrocyte swelling following oxidative stress.
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Affiliation(s)
- M Moriyama
- Department of Pathology, University of Miami School of Medicine, Miami, Florida 33101, USA
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26
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McEneaney V, Dooley R, Yusef YR, Keating N, Quinn U, Harvey BJ, Thomas W. Protein kinase D1 modulates aldosterone-induced ENaC activity in a renal cortical collecting duct cell line. Mol Cell Endocrinol 2010; 325:8-17. [PMID: 20434520 DOI: 10.1016/j.mce.2010.04.019] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2009] [Revised: 04/14/2010] [Accepted: 04/21/2010] [Indexed: 01/31/2023]
Abstract
Aldosterone treatment of M1-CCD cells stimulated an increase in epithelial Na(+) channel (ENaC) alpha-subunit expression that was mainly localized to the apical membrane. PKD1-suppressed cells constitutively expressed ENaCalpha at low abundance, with no increase after aldosterone treatment. In the PKD1-suppressed cells, ENaCalpha was mainly localized proximal to the basolateral surface of the epithelium both before and after aldosterone treatment. Apical membrane insertion of ENaCbeta in response to aldosterone treatment was also sensitive to PKD1 suppression as was the aldosterone-induced rise in the amiloride-sensitive, trans-epithelial current (I(TE)). The interaction of the mineralocorticoid receptor (MR) with specific elements in the promoters of aldosterone responsive genes is stabilized by ligand interaction and phosphorylation. PKD1 suppression inhibited aldosterone-induced SGK-1 expression. The nuclear localization of MR was also blocked by PKD1 suppression and MEK antagonism implicating both these kinases in MR nuclear stabilization. PKD1 thus modulates aldosterone-induced ENaC activity through the modulation of sub-cellular trafficking and the stabilization of MR nuclear localization.
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Affiliation(s)
- Victoria McEneaney
- Department of Molecular Medicine, Royal College of Surgeons in Ireland, Education and Research Centre, Smurfit Building, Beaumont Hospital, Dublin 9, Ireland
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27
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Abstract
Aldosterone regulates blood pressure through its effects on the cardiovascular system and kidney. Aldosterone can also contribute to the development of hypertension that leads to chronic pathologies such as nephropathy and renal fibrosis. Aldosterone directly modulates renal cell proliferation and differentiation as part of normal kidney development. The stimulation of rapidly activated protein kinase cascades is one facet of how aldosterone regulates renal cell growth. These cascades may also contribute to myofibroblastic transformation and cell proliferation observed in pathological conditions of the kidney. Polycystic kidney disease is a genetic disorder that is accelerated by hypertension. EGFR-dependent proliferation of the renal epithelium is a factor in cyst development and trans-activation of EGFR is a key feature in initiating aldosterone-induced signalling cascades. Delineating the components of aldosterone-induced signalling cascades may identify novel therapeutic targets for proliferative diseases of the kidney.
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Affiliation(s)
- Warren Thomas
- Department of Molecular Medicine, Royal College of Surgeons in Ireland, Education and Research Centre, Beaumont Hospital, Dublin 9, Ireland.
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28
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Aldosterone and Cortisol Acutely Stimulate Na+/H+ Exchanger Activity in the Syncytiotrophoblast of the Human Placenta: Effect of Fetal Sex. Placenta 2010; 31:289-94. [DOI: 10.1016/j.placenta.2009.12.025] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/12/2009] [Revised: 12/21/2009] [Accepted: 12/23/2009] [Indexed: 11/18/2022]
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29
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Vinson GP, Coghlan JP. Expanding view of aldosterone action, with an emphasis on rapid action. Clin Exp Pharmacol Physiol 2010; 37:410-6. [PMID: 20409082 DOI: 10.1111/j.1440-1681.2010.05352.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Gavin P Vinson
- School of Biological and Chemical Sciences, Queen Mary University of London, London, UK
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30
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McEneaney V, Dooley R, Harvey BJ, Thomas W. Protein kinase D stabilizes aldosterone-induced ERK1/2 MAP kinase activation in M1 renal cortical collecting duct cells to promote cell proliferation. J Steroid Biochem Mol Biol 2010; 118:18-28. [PMID: 19804826 DOI: 10.1016/j.jsbmb.2009.09.014] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/21/2009] [Revised: 08/29/2009] [Accepted: 09/29/2009] [Indexed: 10/20/2022]
Abstract
Aldosterone elicits transcriptional responses in target tissues and also rapidly stimulates the activation of protein kinase signalling cascades independently of de novo protein synthesis. Here we investigated aldosterone-induced cell proliferation and extra-cellular regulated kinase 1 and 2 (ERK1/2) mitogen activated protein (MAP) kinase signalling in the M1 cortical collecting duct cell line (M1-CCD). Aldosterone promoted the proliferative growth of M1-CCD cells, an effect that was protein kinase D1 (PKD1), PKCdelta and ERK1/2-dependent. Aldosterone induced the rapid activation of ERK1/2 with peaks of activation at 2 and 10 to 30 min after hormone treatment followed by sustained activation lasting beyond 120 min. M1-CCD cells suppressed in PKD1 expression exhibited only the early, transient peaks in ERK1/2 activation without the sustained phase. Aldosterone stimulated the physical association of PKD1 with ERK1/2 within 2 min of treatment. The mineralocorticoid receptor (MR) antagonist RU28318 inhibited the early and late phases of aldosterone-induced ERK1/2 activation, and also aldosterone-induced proliferative cell growth. Aldosterone induced the sub-cellular redistribution of ERK1/2 to the nuclei at 2 min and to cytoplasmic sites, proximal to the nuclei after 30 min. This sub-cellular distribution of ERK1/2 was inhibited in cells suppressed in the expression of PKD1.
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Affiliation(s)
- Victoria McEneaney
- Department of Molecular Medicine, Royal College of Surgeons in Ireland, Education and Research Centre, Beaumont Hospital, Dublin 9, Ireland
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31
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Grossmann C, Gekle M. New aspects of rapid aldosterone signaling. Mol Cell Endocrinol 2009; 308:53-62. [PMID: 19549592 DOI: 10.1016/j.mce.2009.02.005] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/09/2008] [Revised: 01/22/2009] [Accepted: 02/17/2009] [Indexed: 12/20/2022]
Abstract
Aldosterone, the endogenous ligand of the mineralocorticoid receptor (MR) in humans, is a steroid hormone that regulates salt and water homeostasis. Recently, additional pathophysiological effects in the renocardiovascular system have been identified. Besides genomic effects mediated by activated MR, rapid aldosterone actions that are independent of translation and transcription have been documented. While these nongenomic actions influence electrolyte homeostasis, pH and cell volume in classical MR target organs, they also participate in pathophysiological effects in the renocardiovascular system causing endothelial dysfunction, inflammation and remodeling. The mechanisms conveying these rapid effects consist of a multitude of signaling molecules and include a cross-talk with genomic aldosterone effects as well as with angiotensin II and epidermal growth factor receptor signaling. Rapid corticosteroid signaling via the MR has also been demonstrated in the brain. Altogether, the function of nongenomic aldosterone effects seems to be to modulate other signaling cascades, depending on the surrounding milieu.
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Affiliation(s)
- C Grossmann
- Julius-Bernstein-Institut für Physiologie, Universität Halle-Wittenberg, Halle/Saale, Germany.
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32
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Pergher PS, Leite-Dellova D, de Mello-Aires M. Direct action of aldosterone on bicarbonate reabsorption in in vivo cortical proximal tubule. Am J Physiol Renal Physiol 2009; 296:F1185-93. [DOI: 10.1152/ajprenal.90217.2008] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The direct action of aldosterone (10−12 M) on net bicarbonate reabsorption ( JHCO3−) was evaluated by stationary microperfusion of an in vivo middle proximal tubule (S2) of rat kidney, using H ion-sensitive microelectrodes. Aldosterone in luminally perfused tubules caused a significant increase in JHCO3− from a mean control value of 2.84 ± 0.08 [49/19 ( n° of measurements/ n° of tubules)] to 4.20 ± 0.15 nmol·cm−2·s−1 (58/10). Aldosterone perfused into peritubular capillaries also increased JHCO3−, compared with basal levels during intact capillary perfusion with blood. In addition, in isolated perfused tubules aldosterone causes a transient increase of cytosolic free calcium ([Ca2+]i), monitored fluorometrically. In the presence of ethanol (in similar concentration used to prepare the hormonal solution), spironolactone (10−6 M, a mineralocorticoid receptor antagonist), actinomycin D (10−6 M, an inhibitor of gene transcription), or cycloheximide (40 mM, an inhibitor of protein synthesis), the JHCO3− and the [Ca2+]i were not different from the control value; these drugs also did not prevent the stimulatory effect of aldosterone on JHCO3− and on [Ca2+]i. However, in the presence of RU 486 alone [10−6 M, a classic glucocorticoid receptor (GR) antagonist], a significant decrease on JHCO3− and on [Ca2+]i was observed; this antagonist also inhibited the stimulatory effect of aldosterone on JHCO3− and on [Ca2+]i. These studies indicate that luminal or peritubular aldosterone (10−12 M) has a direct nongenomic stimulatory effect on JHCO3− and on [Ca2+]i in proximal tubule and that probably GR participates in this process. The data also indicate that endogenous aldosterone stimulates JHCO3− in middle proximal tubule.
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33
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Silva GB, Garvin JL. Angiotensin II-dependent hypertension increases Na transport-related oxygen consumption by the thick ascending limb. Hypertension 2008; 52:1091-8. [PMID: 19001187 DOI: 10.1161/hypertensionaha.108.120212] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Renal medullary superoxide (O(2)(-)) increases in angiotensin (Ang) II-dependent hypertension. O(2)(-) increases thick ascending limb Na transport, but the effect of Ang II-dependent hypertension on the thick ascending limb is unknown. We hypothesized that Ang II-dependent hypertension increases thick ascending limb NaCl transport because of enhanced O(2)(-) production and increased protein kinase C (PKC) alpha activity. We measured the effect of Ang II-dependent hypertension on furosemide-sensitive oxygen consumption (a measure of Na transport), O(2)(-) production, and PKCalpha translocation (a measure of PKCalpha activity) in thick ascending limb suspensions. Ang II-dependent hypertension increased furosemide-sensitive oxygen consumption (26.2+/-1.0% versus 36.6+/-1.2% of total oxygen consumption; P<0.01). O(2)(-) was also increased (1.1+/-0.2 versus 3.2+/-0.5 nmol of O(2)(-)/min per milligram of protein; P<0.03) in thick ascending limbs. Unilateral renal infusion of Tempol decreased O(2)(-) (2.4+/-0.4 versus 1.2+/-0.2 nmol of O(2)(-)/min per milligram of protein; P<0.04) and furosemide-sensitive oxygen consumption (32.8+/-1.3% versus 24.0+/-2.1% of total oxygen consumption; P<0.01) in hypertensive rats. Tempol did not affect O(2)(-) or furosemide-sensitive oxygen consumption in normotensive controls and did not alter systolic blood pressure. Ang II-dependent hypertension increased PKCalpha translocation (5.7+/-0.3 versus 13.8+/-1.4 AU per milligram of protein; P<0.01). Unilateral renal infusion of Tempol reduced PKCalpha translocation (5.0+/-0.9 versus 10.4+/-2.6 AU per milligram of protein; P<0.04) in hypertensive rats. Unilateral renal infusion of the PKCalpha inhibitor Gö6976 reduced furosemide-sensitive oxygen consumption (37.4+/-1.5% versus 25.1+/-1.0% of total oxygen consumption; P<0.01) in hypertensive rats. We conclude that Ang II-dependent hypertension enhances thick ascending limb Na transport-related oxygen consumption by increasing O(2)(-) and PKCalpha activity.
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Affiliation(s)
- Guillermo B Silva
- Division of Hypertension and Vascular Research, Henry Ford Hospital, Detroit, Michigan 48202, USA
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Leite-Dellova DCA, Oliveira-Souza M, Malnic G, Mello-Aires M. Genomic and nongenomic dose-dependent biphasic effect of aldosterone on Na+/H+ exchanger in proximal S3 segment: role of cytosolic calcium. Am J Physiol Renal Physiol 2008; 295:F1342-52. [PMID: 18715944 DOI: 10.1152/ajprenal.00048.2008] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The effects of aldosterone on the intracellular pH recovery rate (pHirr) via Na+/H+ exchanger and on the [Ca2+]i were investigated in isolated rat S3 segment. Aldosterone [10(-12), 10(-10), or 10(-8) M with 1-h, 15- or 2-min preincubation (pi)] caused a dose-dependent increase in the pHirr, but aldosterone (10(-6) M with 1-h, 15- or 2-min pi) decreased it (these effects were prevented by HOE694 but not by S3226). After 1 min of aldosterone pi, there was a transient and dose-dependent increase of the [Ca2+]i and after 6-min pi there was a new increase of [Ca2+]i that persisted after 1 h. Spironolactone, actinomycin D, or cycloheximide did not affect the effects of aldosterone (15- or 2-min pi) but inhibited the effects of aldosterone (1-h pi) on pHirr and on [Ca2+]i. RU 486 prevented the stimulatory effect of aldosterone (10(-12) M, 15- or 2-min pi) on both parameters and maintained the inhibitory effect of aldosterone (10(-6) M, 15- or 2-min pi) on the pHirr but reversed its stimulatory effect on the [Ca2+]i to an inhibitory effect. The data indicate a genomic (1 h, via MR) and a nongenomic action (15 or 2 min, probably via GR) on [Ca2+]i and on the basolateral NHE1 and are compatible with stimulation of the NHE1 by increases in [Ca2+]i in the lower range (at 10(-12) M aldosterone) and inhibition by increases at high levels (at 10(-6) M aldosterone) or decreases in [Ca2+]i (at 10(-6) M aldosterone plus RU 486).
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Affiliation(s)
- D C A Leite-Dellova
- Department of Physiology and Biophysics, Instituto de Ciências Biomédicas, University of São Paulo, São Paulo 05508-900, Brazil. )
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Lösel RM, Wehling M. Classic versus non-classic receptors for nongenomic mineralocorticoid responses: emerging evidence. Front Neuroendocrinol 2008; 29:258-67. [PMID: 17976711 DOI: 10.1016/j.yfrne.2007.09.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/05/2007] [Revised: 09/16/2007] [Accepted: 09/25/2007] [Indexed: 01/03/2023]
Abstract
Mineralocorticoids, which are synthesized locally in the central nervous system in addition to their adrenal production, trigger both genomic and nongenomic responses. Several functions of mineralocorticoids in the CNS are known to date, which are reviewed along with nongenomic responses in other tissues. A controversy regarding the identity of receptors that mediate nongenomic, transcription-independent cellular responses to steroids is presently attracting considerable scientific interest. While there is strong evidence for classic receptors belonging to the nuclear receptor superfamily to mediate nongenomic steroid effects in some cases, it does not exist for others. Recent findings on new and unexpected properties of classic receptors have partially withdrawn the interest from novel, non-classic membrane receptors, which are being progressively identified at present. This has been facilitated by the robust and elaborate toolkit for classic receptor studies in contrast to the comparably immature research tools for alternative receptors. To know the nature of receptors involved may be the key to beneficial medical translation of specific and targeted steroid responses.
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Affiliation(s)
- Ralf M Lösel
- Clinical Pharmacology Mannheim, University of Heidelberg, Mannheim, Germany
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Harvey BJ, Alzamora R, Stubbs AK, Irnaten M, McEneaney V, Thomas W. Rapid responses to aldosterone in the kidney and colon. J Steroid Biochem Mol Biol 2008; 108:310-7. [PMID: 17951051 DOI: 10.1016/j.jsbmb.2007.09.005] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Aldosterone is a crucial modulator of ion transport across high resistance epithelia and regulates whole body electrolyte balance through its effects on the kidney and colon. The net consequence of aldosterone release is to promote salt conservation. The genomic mechanism of aldosterone action is relatively well characterized and the role of the classical mineralocorticoid receptor as a ligand-dependent transcription factor is well established. The rapid effects of aldosterone on target tissues are less well understood and there is still controversy over the identity of the aldosterone non-genomic receptor. Greater understanding of the physiological consequences of aldosterone's rapid responses in the kidney and colon has been achieved through the identification of definite and putative membrane targets and their signaling regulators.
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Affiliation(s)
- Brian J Harvey
- Department of Molecular Medicine, Royal College of Surgeons in Ireland, Beaumont Hospital, Dublin 9, Ireland.
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McEneaney V, Harvey BJ, Thomas W. Aldosterone rapidly activates protein kinase D via a mineralocorticoid receptor/EGFR trans-activation pathway in the M1 kidney CCD cell line. J Steroid Biochem Mol Biol 2007; 107:180-90. [PMID: 17681751 DOI: 10.1016/j.jsbmb.2007.03.043] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2006] [Accepted: 03/13/2007] [Indexed: 10/23/2022]
Abstract
Aldosterone elicits physiological responses through the modulation of gene expression and by stimulating signaling processes. Here we investigated the activation pathway of protein kinase D1 (PKD1) by aldosterone in the murine M1 renal cortical collecting duct cell line. Aldosterone stimulated a rapid increase in PKD1 activity peaking at 2-5 min and at 30 min after treatment that was insensitive to inhibitors of transcription or translation. PKD1 was not activated by aldosterone in MR null NIH-3T3 fibroblasts or M1-CCD cells propagated without dexamethasone, which did not express MR. PKD1 activation was sensitive to the MR antagonists spironolactone and RU28318 but not to the glucocorticoid receptor antagonist RU486. Aldosterone activation of PKD1 was inhibited by the epidermal growth factor (EGFR) antagonist tyrphostin AG1478 and by the c-Src inhibitor PP2. Western blotting revealed EGFR phosphorylation following aldosterone treatment at the c-Src tyrosine kinase-specific residue Tyr845. The activation of c-Src was dependent on its interaction with HSP84, since HSP84 antagonist 17-AAG inhibited both the phosphorylation of EGFR in response to aldosterone by c-Src and also the subsequent activation of PKD1.
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Affiliation(s)
- Victoria McEneaney
- Department of Molecular Medicine, Royal College of Surgeons in Ireland Education and Research Centre, Smurfit Building, Beaumont Hospital, Dublin 9, Ireland
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38
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Aldosterone-stimulated PKC signalling cascades: from receptor to effector. Biochem Soc Trans 2007; 35:1049-51. [DOI: 10.1042/bst0351049] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Aldosterone plays an important role in the regulation of blood pressure. The effects of this hormone have classically been described in terms of the transcriptional regulation of genes that facilitate electrolyte transport, particularly across high-resistance epithelia. The protein kinase signalling cascades that are rapidly activated in response to aldosterone are emerging as important modulators of the transcriptional response, and may serve to prime cells for the subsequent transcriptional changes. The activation of protein kinase D through an epidermal growth factor receptor transactivation pathway by aldosterone in renal cells has the potential to impact on cell trafficking events that regulate transporter activity.
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Abstract
Rapid signalling responses stimulated by steroid hormones have been detected in various tissues including the nephron. The significance of these responses in modulating the physiological effects elicited by mineralocorticoids, glucocorticoids and the reproductive hormones in the kidney is now becoming more evident. This review outlines how rapid signalling responses stimulated by these hormones are coupled to the regulation of membrane transport targets that impact upon the reabsorptive and excretory functions of the kidney.
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Affiliation(s)
- Warren Thomas
- Department of Molecular Medicine, Royal College of Surgeons in Ireland Education and Research Centre, Beaumont Hospital, Dublin, Republic of Ireland
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40
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Logvinenko NS, Solenov EI, Ivanova LN. A rapid nongenomic effect of aldosterone on intracellular sodium concentration in the distal nephron segment of the rat. DOKL BIOCHEM BIOPHYS 2006; 406:7-10. [PMID: 16583997 DOI: 10.1134/s1607672906010030] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
- N S Logvinenko
- Institute of Cytology and Genetics, Siberian Division, Russian Academy of Sciences, pr. Akademika Lavrent'eva 10, Novosibirsk, 630090 Russia
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Plotkin MD, Goligorsky MS. Mesenchymal cells from adult kidney support angiogenesis and differentiate into multiple interstitial cell types including erythropoietin-producing fibroblasts. Am J Physiol Renal Physiol 2006; 291:F902-12. [PMID: 16622175 DOI: 10.1152/ajprenal.00396.2005] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Mesenchymal cells have been isolated from embryos and multiple adult organs where they may differentiate into various connective tissue cell types and provide paracrine support for surrounding cells. With the use of a technique for culturing multipotent mesenchymal cells from adult tissues, a fibroblast-like cell clone (4E) was isolated from adult mouse kidney. 4E cells were able to differentiate along multiple mesodermal lineages including cell types located in the renal interstitium such as fibroblasts and pericytes. Coculture of 4E cells with ureteric bud and epithelial cell lines and analysis of resulting changes in gene expression revealed that these cells support angiogenesis and tubulogenesis and expressed genes characteristic of embryonic renal stromal cells. Following subcapsular injection after unilateral ischemia-reperfusion in adult mice, 4E cells migrated to a peritubular interstitial location and expressed interstitial cell markers, whereas cells injected in control kidneys remained stationary. Incubation in hypoxic or anoxic conditions resulted in erythropoietin expression in a small subset of ecto-5'-nucleotidase-positive cells and resulted in increased vascular endothelial growth factor expression in the same cell population. Our findings suggest that the adult kidney may contain interstitial mesenchymal cell progenitors with embryonic stromal cell characteristics that are able to provide paracrine support for surrounding vessels and tubular epithelial cells and differentiate into erythropoietin producing fibroblasts.
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Affiliation(s)
- Matthew D Plotkin
- New York Medical College, Renal Research Institute, BSB C06, 95 Grasslands Rd., Valhalla, NY 10595, USA.
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Soundararajan R, Zhang TT, Wang J, Vandewalle A, Pearce D. A novel role for glucocorticoid-induced leucine zipper protein in epithelial sodium channel-mediated sodium transport. J Biol Chem 2005; 280:39970-81. [PMID: 16216878 DOI: 10.1074/jbc.m508658200] [Citation(s) in RCA: 143] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The steroid hormone aldosterone stimulates sodium (Na+) transport in tight epithelia by altering the expression of target genes that regulate the activity and trafficking of the epithelial sodium channel (ENaC). We performed microarray analysis to identify aldosterone-regulated transcripts in mammalian kidney epithelial cells (mpkC-CD(c14)). One target, glucocorticoid-induced leucine zipper protein (GILZ), was previously identified by serial analysis of gene expression (SAGE); however, its function in epithelial ion transport was unknown. Here we show that GILZ expression is rapidly stimulated by aldosterone in mpkCCD(c14) and that GILZ, in turn, strongly stimulates ENaC-mediated Na+ transport by inhibiting extracellular signal-regulated kinase (ERK) signaling. In Xenopus oocytes with activated ERK, heterologous GILZ expression consistently inhibited phospho-ERK expression and markedly stimulated ENaC-mediated Na+ current, in a manner similar to that of U0126 (a pharmacologic inhibitor of ERK signaling). In mpkCCD(c14) cells, GILZ transfection similarly consistently inhibited phospho-ERK expression and stimulated transepithelial Na+ transport. Furthermore, aldosterone treatment of mpkCCD(c14) cells suppressed phospho-ERK levels with a time course that paralleled their increase of Na+ transport. Finally, GILZ expression markedly increased cell surface ENaC expression in epidermal growth factor-treated mammalian kidney epithelial cells, HEK 293. These observations suggest a novel link between GILZ and regulation of epithelial sodium transport through modulation of ERK signaling and could represent an important pathway for mediating aldosterone actions in health and disease.
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Affiliation(s)
- Rama Soundararajan
- Division of Nephrology, Department of Medicine, University of California at San Francisco, San Francisco, California 94143-0532, USA
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