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Chubanov V, Köttgen M, Touyz RM, Gudermann T. TRPM channels in health and disease. Nat Rev Nephrol 2024; 20:175-187. [PMID: 37853091 DOI: 10.1038/s41581-023-00777-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/25/2023] [Indexed: 10/20/2023]
Abstract
Different cell channels and transporters tightly regulate cytoplasmic levels and the intraorganelle distribution of cations. Perturbations in these processes lead to human diseases that are frequently associated with kidney impairment. The family of melastatin-related transient receptor potential (TRPM) channels, which has eight members in mammals (TRPM1-TRPM8), includes ion channels that are highly permeable to divalent cations, such as Ca2+, Mg2+ and Zn2+ (TRPM1, TRPM3, TRPM6 and TRPM7), non-selective cation channels (TRPM2 and TRPM8) and monovalent cation-selective channels (TRPM4 and TRPM5). Three family members contain an enzymatic protein moiety: TRPM6 and TRPM7 are fused to α-kinase domains, whereas TRPM2 is linked to an ADP-ribose-binding NUDT9 homology domain. TRPM channels also function as crucial cellular sensors involved in many physiological processes, including mineral homeostasis, blood pressure, cardiac rhythm and immunity, as well as photoreception, taste reception and thermoreception. TRPM channels are abundantly expressed in the kidney. Mutations in TRPM genes cause several inherited human diseases, and preclinical studies in animal models of human disease have highlighted TRPM channels as promising new therapeutic targets. Here, we provide an overview of this rapidly evolving research area and delineate the emerging role of TRPM channels in kidney pathophysiology.
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Affiliation(s)
- Vladimir Chubanov
- Walther-Straub Institute of Pharmacology and Toxicology, LMU Munich, Munich, Germany.
| | - Michael Köttgen
- Renal Division, Department of Medicine, Medical Center, Faculty of Medicine, University of Freiburg, Freiburg, Germany
- CIBSS - Centre for Integrative Biological Signalling Studies, Freiburg, Germany
| | - Rhian M Touyz
- Research Institute of McGill University Health Centre, McGill University, Montreal, Quebec, Canada
| | - Thomas Gudermann
- Walther-Straub Institute of Pharmacology and Toxicology, LMU Munich, Munich, Germany.
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2
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Abstract
Mg2+ is essential for many cellular and physiological processes, including muscle contraction, neuronal activity, and metabolism. Consequently, the blood Mg2+ concentration is tightly regulated by balanced intestinal Mg2+ absorption, renal Mg2+ excretion, and Mg2+ storage in bone and soft tissues. In recent years, the development of novel transgenic animal models and identification of Mendelian disorders has advanced our current insight in the molecular mechanisms of Mg2+ reabsorption in the kidney. In the proximal tubule, Mg2+ reabsorption is dependent on paracellular permeability by claudin-2/12. In the thick ascending limb of Henle's loop, the claudin-16/19 complex provides a cation-selective pore for paracellular Mg2+ reabsorption. The paracellular Mg2+ reabsorption in this segment is regulated by the Ca2+-sensing receptor, parathyroid hormone, and mechanistic target of rapamycin (mTOR) signaling. In the distal convoluted tubule, the fine tuning of Mg2+ reabsorption takes place by transcellular Mg2+ reabsorption via transient receptor potential melastatin-like types 6 and 7 (TRPM6/TRPM7) divalent cation channels. Activity of TRPM6/TRPM7 is dependent on hormonal regulation, metabolic activity, and interacting proteins. Basolateral Mg2+ extrusion is still poorly understood but is probably dependent on the Na+ gradient. Cyclin M2 and SLC41A3 are the main candidates to act as Na+/Mg2+ exchangers. Consequently, disturbances of basolateral Na+/K+ transport indirectly result in impaired renal Mg2+ reabsorption in the distal convoluted tubule. Altogether, this review aims to provide an overview of the molecular mechanisms of Mg2+ reabsorption in the kidney, specifically focusing on transgenic mouse models and human hereditary diseases.
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Affiliation(s)
- Jeroen H F de Baaij
- Department of Physiology, Radboud University Medical Center, Nijmegen, The Netherlands
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3
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Oost LJ, Tack CJ, de Baaij JHF. Hypomagnesemia and Cardiovascular Risk in Type 2 Diabetes. Endocr Rev 2022; 44:357-378. [PMID: 36346820 PMCID: PMC10166267 DOI: 10.1210/endrev/bnac028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Revised: 08/22/2022] [Accepted: 11/04/2022] [Indexed: 11/11/2022]
Abstract
Hypomagnesemia is tenfold more common in individuals with type 2 diabetes (T2D), compared to the healthy population. Factors that are involved in this high prevalence are low Mg2+ intake, gut microbiome composition, medication use and presumably genetics. Hypomagnesemia is associated with insulin resistance, which subsequently increases the risk to develop T2D or deteriorates glycaemic control in existing diabetes. Mg2+ supplementation decreases T2D associated features like dyslipidaemia and inflammation; which are important risk factors for cardiovascular disease (CVD). Epidemiological studies have shown an inverse association between serum Mg2+ and the risk to develop heart failure (HF), atrial fibrillation (AF) and microvascular disease in T2D. The potential protective effect of Mg2+ on HF and AF may be explained by reduced oxidative stress, fibrosis and electrical remodeling in the heart. In microvascular disease, Mg2+ reduces the detrimental effects of hyperglycemia and improves endothelial dysfunction. Though, clinical studies assessing the effect of long-term Mg2+ supplementation on CVD incidents are lacking and gaps remain on how Mg2+ may reduce CVD risk in T2D. Despite the high prevalence of hypomagnesemia in people with T2D, routine screening of Mg2+ deficiency to provide Mg2+ supplementation when needed is not implemented in clinical care as sufficient clinical evidence is lacking. In conclusion, hypomagnesemia is common in people with T2D and is both involved as cause, probably through molecular mechanisms leading to insulin resistance, and consequence and is prospectively associated with development of HF, AF and microvascular complications. Whether long-term supplementation of Mg2+ is beneficial, however, remains to be determined.
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Affiliation(s)
- Lynette J Oost
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Cees J Tack
- Department of Internal Medicine, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Jeroen H F de Baaij
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
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4
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Suksridechacin N, Thongon N. Fibroblast growth factor-23 and parathyroid hormone suppress small intestinal magnesium absorption. Physiol Rep 2022; 10:e15247. [PMID: 35385223 PMCID: PMC8985197 DOI: 10.14814/phy2.15247] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 02/22/2022] [Accepted: 03/15/2022] [Indexed: 04/12/2023] Open
Abstract
In the present study, we examined the systemic and direct effects of parathyroid hormone (PTH) and fibroblast growth factor-23 (FGF-23) on duodenal, jejunal, and ileal Mg2+ absorption. The rats were injected with FGF-23 or PTH for 5 h before collecting the duodenum, jejunum, and ileum for Mg2+ transport analysis in Ussing chambers. The duodenum, jejunum, and ileum were directly exposed to FGF-23, PTH, or FGF-23 plus PTH with or without cell signaling inhibitors for 150 min in Ussing chambers prior to performing the Mg2+ transport study. The small intestinal tissues were also subjected to western blot analyses for FGF receptor (FGFR), PTH receptor (PTHR), Klotho, transient receptor potential melastatin 6 (TRPM6), and cyclin as well as the cystathionine β-synthase domain divalent metal cation transport mediator 4 (CNNM4) expression. The small intestine abundantly expressed FGFR and PTHR proteins, whereas, Klotho was not expressed in rat small intestine. Systemic PTH or FGF-23 injection significantly suppressed transcellular Mg2+ transport in the duodenum and jejunum. Direct FGF-23-, PTH-, or FGF-23 plus PTH exposure also suppressed transcellular Mg2+ absorption in the duodenum and jejunum. There was no additional inhibitory effect of PTH and FGF-23 on intestinal Mg2+ absorption. The inhibitory effect of PTH, FGF-23, or FGF-23 plus PTH was abolished by Gö 6850. Systemic PTH- or FGF-23-injection significantly decreased membranous TRPM6 expression, but increased cytosolic CNNM4 expression in the duodenum, jejunum, and ileum. In the present study, we propose a novel magnesiotropic action of PTH and FGF-23 by modulating small intestinal Mg2+ absorption.
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Affiliation(s)
- Nasisorn Suksridechacin
- Division of PhysiologyDepartment of Biomedical SciencesFaculty of Allied Health SciencesBurapha UniversityChonburiThailand
- Biodiversity Research CentreThailand Institute of Scientific and Technological ResearchPathumthaniThailand
| | - Narongrit Thongon
- Division of PhysiologyDepartment of Biomedical SciencesFaculty of Allied Health SciencesBurapha UniversityChonburiThailand
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5
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Licitra F, Giovannelli P, Di Donato M, Monaco A, Galasso G, Migliaccio A, Castoria G. New Insights and Emerging Therapeutic Approaches in Prostate Cancer. Front Endocrinol (Lausanne) 2022; 13:840787. [PMID: 35222290 PMCID: PMC8873523 DOI: 10.3389/fendo.2022.840787] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Accepted: 01/20/2022] [Indexed: 11/13/2022] Open
Abstract
Prostate cancer is the second most frequently diagnosed cancer in men and several therapeutic approaches are currently available for patient's care. Although the androgen receptor status represents a good predictor of response to androgen deprivation therapy, prostate cancer frequently becomes resistant to this approach and spreads. The molecular mechanisms that contribute to progression and drug-resistance of this cancer remain still debated. However, few therapeutic options are available for patient's management, at this stage. Recent years have seen a great expansion of the studies concerning the role of stromal-epithelial interactions and tumor microenvironment in prostate cancer progression. The findings so far collected have provided new insights into diagnostic and clinical management of prostate cancer patients. Further, new fascinating aspects concerning the intersection of the androgen receptor with survival factors as well as calcium channels have been reported in cultured prostate cancer cells and mouse models. The results of these researches have opened the way for a better understanding of the basic mechanisms involved in prostate cancer invasion and drug-resistance. They have also significantly expanded the list of new biomarkers and druggable targets in prostate cancer. The primary aim of this manuscript is to provide an update of these issues, together with their translational aspects. Exploiting the power of novel promising therapeutics would increase the success rate in the diagnostic path and clinical management of patients with advanced disease.
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Di Donato M, Ostacolo C, Giovannelli P, Di Sarno V, Monterrey IMG, Campiglia P, Migliaccio A, Bertamino A, Castoria G. Therapeutic potential of TRPM8 antagonists in prostate cancer. Sci Rep 2021; 11:23232. [PMID: 34853378 PMCID: PMC8636514 DOI: 10.1038/s41598-021-02675-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Accepted: 11/22/2021] [Indexed: 12/27/2022] Open
Abstract
Transient receptor potential melastatin-8 (TRPM8) represents an emerging target in prostate cancer, although its mechanism of action remains unclear. Here, we have characterized and investigated the effects of TRPM8 modulators in prostate cancer aggressiveness disclosing the molecular mechanism underlying their biological activity. Patch-clamp and calcium fluorometric assays were used to characterize the synthesized compounds. Androgen-stimulated prostate cancer-derived cells were challenged with the compounds and the DNA synthesis was investigated in a preliminary screening. The most effective compounds were then employed to inhibit the pro-metastatic behavior of in various PC-derived cells, at different degree of malignancy. The effect of the compounds was then assayed in prostate cancer cell-derived 3D model and the molecular targets of selected compounds were lastly identified using transcriptional and non-transcriptional reporter assays. TRPM8 antagonists inhibit the androgen-dependent prostate cancer cell proliferation, migration and invasiveness. They are highly effective in reverting the androgen-induced increase in prostate cancer cell spheroid size. The compounds also revert the proliferation of castrate-resistant prostate cancer cells, provided they express the androgen receptor. In contrast, no effects were recorded in prostate cancer cells devoid of the receptor. Selected antagonists interfere in non-genomic androgen action and abolish the androgen-induced androgen receptor/TRPM8 complex assembly as well as the increase in intracellular calcium levels in prostate cancer cells. Our results shed light in the processes controlling prostate cancer progression and make the transient receptor potential melastatin-8 as a ‘druggable’ target in the androgen receptor-expressing prostate cancers.
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Affiliation(s)
- Marzia Di Donato
- Department of Precision Medicine, School of Medicine, University of Campania 'L. Vanvitelli', Via L. De Crecchio 7, 80138, Naples, Italy
| | - Carmine Ostacolo
- Department of Pharmacy, University Federico II of Naples, Via D. Montesano 49, 80131, Naples, Italy
| | - Pia Giovannelli
- Department of Precision Medicine, School of Medicine, University of Campania 'L. Vanvitelli', Via L. De Crecchio 7, 80138, Naples, Italy
| | - Veronica Di Sarno
- Department of Pharmacy, University of Salerno, Via G.Paolo II, 84084, Fisciano, SA, Italy
| | - Isabel M Gomez Monterrey
- Department of Pharmacy, University Federico II of Naples, Via D. Montesano 49, 80131, Naples, Italy
| | - Pietro Campiglia
- Department of Pharmacy, University of Salerno, Via G.Paolo II, 84084, Fisciano, SA, Italy
| | - Antimo Migliaccio
- Department of Precision Medicine, School of Medicine, University of Campania 'L. Vanvitelli', Via L. De Crecchio 7, 80138, Naples, Italy
| | - Alessia Bertamino
- Department of Pharmacy, University of Salerno, Via G.Paolo II, 84084, Fisciano, SA, Italy.
| | - Gabriella Castoria
- Department of Precision Medicine, School of Medicine, University of Campania 'L. Vanvitelli', Via L. De Crecchio 7, 80138, Naples, Italy.
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7
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Franken GAC, Adella A, Bindels RJM, Baaij JHF. Mechanisms coupling sodium and magnesium reabsorption in the distal convoluted tubule of the kidney. Acta Physiol (Oxf) 2021; 231:e13528. [PMID: 32603001 PMCID: PMC7816272 DOI: 10.1111/apha.13528] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Revised: 05/29/2020] [Accepted: 06/22/2020] [Indexed: 02/06/2023]
Abstract
Hypomagnesaemia is a common feature of renal Na+ wasting disorders such as Gitelman and EAST/SeSAME syndrome. These genetic defects specifically affect Na+ reabsorption in the distal convoluted tubule, where Mg2+ reabsorption is tightly regulated. Apical uptake via TRPM6 Mg2+ channels and basolateral Mg2+ extrusion via a putative Na+ -Mg2+ exchanger determines Mg2+ reabsorption in the distal convoluted tubule. However, the mechanisms that explain the high incidence of hypomagnesaemia in patients with Na+ wasting disorders of the distal convoluted tubule are largely unknown. In this review, we describe three potential mechanisms by which Mg2+ reabsorption in the distal convoluted tubule is linked to Na+ reabsorption. First, decreased activity of the thiazide-sensitive Na+ /Cl- cotransporter (NCC) results in shortening of the segment, reducing the Mg2+ reabsorption capacity. Second, the activity of TRPM6 and NCC are determined by common regulatory pathways. Secondary effects of NCC dysregulation such as hormonal imbalance, therefore, might disturb TRPM6 expression. Third, the basolateral membrane potential, maintained by the K+ permeability and Na+ -K+ -ATPase activity, provides the driving force for Na+ and Mg2+ extrusion. Depolarisation of the basolateral membrane potential in Na+ wasting disorders of the distal convoluted tubule may therefore lead to reduced activity of the putative Na+ -Mg2+ exchanger SLC41A1. Elucidating the interconnections between Mg2+ and Na+ transport in the distal convoluted tubule is hampered by the currently available models. Our analysis indicates that the coupling of Na+ and Mg2+ reabsorption may be multifactorial and that advanced experimental models are required to study the molecular mechanisms.
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Affiliation(s)
- Gijs A. C. Franken
- Department of Physiology Radboud Institute for Molecular Life SciencesRadboud University Medical Center Nijmegen the Netherlands
| | - Anastasia Adella
- Department of Physiology Radboud Institute for Molecular Life SciencesRadboud University Medical Center Nijmegen the Netherlands
| | - René J. M. Bindels
- Department of Physiology Radboud Institute for Molecular Life SciencesRadboud University Medical Center Nijmegen the Netherlands
| | - Jeroen H. F. Baaij
- Department of Physiology Radboud Institute for Molecular Life SciencesRadboud University Medical Center Nijmegen the Netherlands
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8
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Steroids and TRP Channels: A Close Relationship. Int J Mol Sci 2020; 21:ijms21113819. [PMID: 32471309 PMCID: PMC7325571 DOI: 10.3390/ijms21113819] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Revised: 05/02/2020] [Accepted: 05/04/2020] [Indexed: 02/07/2023] Open
Abstract
Transient receptor potential (TRP) channels are remarkable transmembrane protein complexes that are essential for the physiology of the tissues in which they are expressed. They function as non-selective cation channels allowing for the signal transduction of several chemical, physical and thermal stimuli and modifying cell function. These channels play pivotal roles in the nervous and reproductive systems, kidney, pancreas, lung, bone, intestine, among others. TRP channels are finely modulated by different mechanisms: regulation of their function and/or by control of their expression or cellular/subcellular localization. These mechanisms are subject to being affected by several endogenously-produced compounds, some of which are of a lipidic nature such as steroids. Fascinatingly, steroids and TRP channels closely interplay to modulate several physiological events. Certain TRP channels are affected by the typical genomic long-term effects of steroids but others are also targets for non-genomic actions of some steroids that act as direct ligands of these receptors, as will be reviewed here.
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9
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Gkika D, Lolignier S, Grolez GP, Bavencoffe A, Shapovalov G, Gordienko D, Kondratskyi A, Meleine M, Prival L, Chapuy E, Etienne M, Eschalier A, Shuba Y, Skryma R, Busserolles J, Prevarskaya N. Testosterone-androgen receptor: The steroid link inhibiting TRPM8-mediated cold sensitivity. FASEB J 2020; 34:7483-7499. [PMID: 32277850 DOI: 10.1096/fj.201902270r] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Revised: 01/10/2020] [Accepted: 03/18/2020] [Indexed: 11/11/2022]
Abstract
Recent studies have revealed gender differences in cold perception, and pointed to a possible direct action of testosterone (TST) on the cold-activated TRPM8 (Transient Receptor Potential Melastatin Member 8) channel. However, the mechanisms by which TST influences TRPM8-mediated sensory functions remain elusive. Here, we show that TST inhibits TRPM8-mediated mild-cold perception through the noncanonical engagement of the Androgen Receptor (AR). Castration of both male rats and mice increases sensitivity to mild cold, and this effect depends on the presence of intact TRPM8 and AR. TST in nanomolar concentrations suppresses whole-cell TRPM8-mediated currents and single-channel activity in native dorsal root ganglion (DRG) neurons and HEK293 cells co-expressing recombinant TRPM8 and AR, but not TRPM8 alone. AR cloned from rat DRGs shows no difference from standard AR. However, biochemical assays and confocal imaging reveal the presence of AR on the cell surface and its interaction with TRPM8 in response to TST, leading to an inhibition of channel activity.
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Affiliation(s)
- Dimitra Gkika
- Univ. Lille, Inserm, U1003 - PHYCEL - Physiologie Cellulaire, Lille, France
| | - Stéphane Lolignier
- Université Clermont Auvergne, Inserm, Neuro-Dol, Clermont-Ferrand, France.,Institut Analgesia, Faculté de Médecine, Clermont-Ferrand, France
| | - Guillaume P Grolez
- Univ. Lille, Inserm, U1003 - PHYCEL - Physiologie Cellulaire, Lille, France
| | - Alexis Bavencoffe
- Univ. Lille, Inserm, U1003 - PHYCEL - Physiologie Cellulaire, Lille, France
| | - Georges Shapovalov
- Univ. Lille, Inserm, U1003 - PHYCEL - Physiologie Cellulaire, Lille, France
| | - Dmitri Gordienko
- Univ. Lille, Inserm, U1003 - PHYCEL - Physiologie Cellulaire, Lille, France
| | - Artem Kondratskyi
- Univ. Lille, Inserm, U1003 - PHYCEL - Physiologie Cellulaire, Lille, France.,Department of Neuromuscular Physiology, Bogomoletz Institute of Physiology NASU, Kyiv, Ukraine
| | - Mathieu Meleine
- Université Clermont Auvergne, Inserm, Neuro-Dol, Clermont-Ferrand, France.,Institut Analgesia, Faculté de Médecine, Clermont-Ferrand, France
| | - Laetitia Prival
- Université Clermont Auvergne, Inserm, Neuro-Dol, Clermont-Ferrand, France.,Institut Analgesia, Faculté de Médecine, Clermont-Ferrand, France
| | - Eric Chapuy
- Université Clermont Auvergne, Inserm, Neuro-Dol, Clermont-Ferrand, France.,Institut Analgesia, Faculté de Médecine, Clermont-Ferrand, France
| | - Monique Etienne
- Université Clermont Auvergne, Inserm, Neuro-Dol, Clermont-Ferrand, France.,Institut Analgesia, Faculté de Médecine, Clermont-Ferrand, France
| | - Alain Eschalier
- Université Clermont Auvergne, Inserm, Neuro-Dol, Clermont-Ferrand, France.,Institut Analgesia, Faculté de Médecine, Clermont-Ferrand, France
| | - Yaroslav Shuba
- Univ. Lille, Inserm, U1003 - PHYCEL - Physiologie Cellulaire, Lille, France.,Department of Neuromuscular Physiology, Bogomoletz Institute of Physiology NASU, Kyiv, Ukraine
| | - Roman Skryma
- Univ. Lille, Inserm, U1003 - PHYCEL - Physiologie Cellulaire, Lille, France
| | - Jérôme Busserolles
- Université Clermont Auvergne, Inserm, Neuro-Dol, Clermont-Ferrand, France.,Institut Analgesia, Faculté de Médecine, Clermont-Ferrand, France
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10
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Bouras H, Roig SR, Kurstjens S, Tack CJJ, Kebieche M, de Baaij JHF, Hoenderop JGJ. Metformin regulates TRPM6, a potential explanation for magnesium imbalance in type 2 diabetes patients. Can J Physiol Pharmacol 2020; 98:400-411. [PMID: 32017603 DOI: 10.1139/cjpp-2019-0570] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Metformin therapy is associated with lower serum magnesium (Mg2+) levels in type 2 diabetes patients. The TRPM6 channel determines the fine-tuning of Mg2+ (re)absorption in intestine and kidney. Therefore, we aimed to investigate the short- and long-term effects of metformin on TRPM6. Patch clamp recordings and biotinylation assays were performed upon 1 h of incubation with metformin in TRPM6-transfected HEK293 cells. Additionally, 24 h of treatment of mDCT15 kidney and hCaco-2 colon cells with metformin was applied to measure the effects on endogenous TRPM6 expression by quantitative real-time PCR. To assess Mg2+ absorption, 25Mg2+ uptake measurements were performed using inductively coupled plasma mass spectrometry. Short-term effects of metformin significantly increased TRPM6 activity and its cell surface trafficking. In contrast, long-term effects significantly decreased TRPM6 mRNA expression and 25Mg2+ uptake. Metformin lowered TRPM6 mRNA levels independently of insulin- and AMPK-mediated pathways. Moreover, in type 2 diabetes patients, metformin therapy was associated with lower plasma Mg2+ concentrations and fractional excretion of Mg2+. Thereby, short-term metformin treatment increases TRPM6 activity explained by enhanced cell surface expression. Conversely, long-term metformin treatment results in downregulation of TRPM6 gene expression in intestine and kidney cells. This long-term effect translated in an inverse correlation between metformin and plasma Mg2+ concentration in type 2 diabetes patients.
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Affiliation(s)
- Hacene Bouras
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, the Netherlands.,Faculty of Nature and Life Sciences, University of Mohamed Seddik Ben Yahia, Jijel, Algeria
| | - Sara R Roig
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Steef Kurstjens
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Cees J J Tack
- Department of Internal Medicine, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Mohamed Kebieche
- Faculty of Nature and Life Sciences, University of Batna2, Algeria
| | - Jeroen H F de Baaij
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Joost G J Hoenderop
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, the Netherlands
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11
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Verma G, Dixit A, Nunemaker CS. A Putative Prohibitin-Calcium Nexus in β-Cell Mitochondria and Diabetes. J Diabetes Res 2020; 2020:7814628. [PMID: 33354575 PMCID: PMC7737164 DOI: 10.1155/2020/7814628] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 08/01/2020] [Accepted: 08/05/2020] [Indexed: 12/21/2022] Open
Abstract
The role of mitochondria in apoptosis is well known; however, the mechanisms linking mitochondria to the proapoptotic effects of proinflammatory cytokines, hyperglycemia, and glucolipotoxicity are not completely understood. Complex Ca2+ signaling has emerged as a critical contributor to these proapoptotic effects and has gained significant attention in regulating the signaling processes of mitochondria. In pancreatic β-cells, Ca2+ plays an active role in β-cell function and survival. Prohibitin (PHB), a mitochondrial chaperone, is actively involved in maintaining the architecture of mitochondria. However, its possible interaction with Ca2+-activated signaling pathways has not been explored. The present review aims to examine potential crosstalk between Ca2+ signaling and PHB function in pancreatic β-cells. Moreover, this review will focus on the effects of cytokines and glucolipotoxicity on Ca2+ signaling and its possible interaction with PHB. Improved understanding of this important mitochondrial protein may aid in the design of more targeted drugs to identify specific pathways involved with stress-induced dysfunction in the β-cell.
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Affiliation(s)
- Gaurav Verma
- Molecular Metabolism, Lund University Diabetes Centre, Malmö -21428, Sweden
- School of Biotechnology, Jawaharlal Nehru University, -110067, New Delhi, India
| | - Aparna Dixit
- School of Biotechnology, Jawaharlal Nehru University, -110067, New Delhi, India
| | - Craig S. Nunemaker
- HCOM-Biomedical Sciences, Ohio University, Athens Camp, US-45701 Ohio, USA
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12
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van der Wijst J, Belge H, Bindels RJM, Devuyst O. Learning Physiology From Inherited Kidney Disorders. Physiol Rev 2019; 99:1575-1653. [PMID: 31215303 DOI: 10.1152/physrev.00008.2018] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The identification of genes causing inherited kidney diseases yielded crucial insights in the molecular basis of disease and improved our understanding of physiological processes that operate in the kidney. Monogenic kidney disorders are caused by mutations in genes coding for a large variety of proteins including receptors, channels and transporters, enzymes, transcription factors, and structural components, operating in specialized cell types that perform highly regulated homeostatic functions. Common variants in some of these genes are also associated with complex traits, as evidenced by genome-wide association studies in the general population. In this review, we discuss how the molecular genetics of inherited disorders affecting different tubular segments of the nephron improved our understanding of various transport processes and of their involvement in homeostasis, while providing novel therapeutic targets. These include inherited disorders causing a dysfunction of the proximal tubule (renal Fanconi syndrome), with emphasis on epithelial differentiation and receptor-mediated endocytosis, or affecting the reabsorption of glucose, the handling of uric acid, and the reabsorption of sodium, calcium, and magnesium along the kidney tubule.
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Affiliation(s)
- Jenny van der Wijst
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center , Nijmegen , The Netherlands ; Institute of Physiology, University of Zurich , Zurich , Switzerland ; and Division of Nephrology, Institute of Experimental and Clinical Research (IREC), Medical School, Université catholique de Louvain, Brussels, Belgium
| | - Hendrica Belge
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center , Nijmegen , The Netherlands ; Institute of Physiology, University of Zurich , Zurich , Switzerland ; and Division of Nephrology, Institute of Experimental and Clinical Research (IREC), Medical School, Université catholique de Louvain, Brussels, Belgium
| | - René J M Bindels
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center , Nijmegen , The Netherlands ; Institute of Physiology, University of Zurich , Zurich , Switzerland ; and Division of Nephrology, Institute of Experimental and Clinical Research (IREC), Medical School, Université catholique de Louvain, Brussels, Belgium
| | - Olivier Devuyst
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center , Nijmegen , The Netherlands ; Institute of Physiology, University of Zurich , Zurich , Switzerland ; and Division of Nephrology, Institute of Experimental and Clinical Research (IREC), Medical School, Université catholique de Louvain, Brussels, Belgium
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13
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TRPM8-androgen receptor association within lipid rafts promotes prostate cancer cell migration. Cell Death Dis 2019; 10:652. [PMID: 31501416 PMCID: PMC6733924 DOI: 10.1038/s41419-019-1891-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Revised: 08/12/2019] [Accepted: 08/20/2019] [Indexed: 12/24/2022]
Abstract
In prostate carcinogenesis, androgens are known to control the expression of the transient receptor potential melastatin 8 (TRPM8) protein via activation of androgen receptor (AR). Overexpression and/or activity of TRPM8 channel was shown to suppress prostate cancer (PCa) cell migration. Here we report that at certain concentrations androgens facilitate PCa cell migration. We show that underlying mechanism is inhibition of TRPM8 by activated AR which interacts with the channel within lipid rafts microdomains of the plasma membrane. Thus, our study has identified an additional nongenomic mechanism of the TRPM8 channel regulation by androgens that should be taken into account upon the development of novel therapeutic strategies.
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14
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Diabetes-induced hypomagnesemia is not modulated by metformin treatment in mice. Sci Rep 2019; 9:1770. [PMID: 30742025 PMCID: PMC6370757 DOI: 10.1038/s41598-018-38351-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Accepted: 12/21/2018] [Indexed: 12/24/2022] Open
Abstract
Approximately 30% of patients with type 2 diabetes mellitus (T2D) have hypomagnesemia (blood magnesium (Mg2+) concentration <0.7 mmol/L). In T2D patients, treatment with metformin is associated with reduced blood Mg2+ levels. To investigate how T2D and metformin affect Mg2+ homeostasis db/m and db/db mice were treated with metformin or placebo. Mice were housed in metabolic cages to measure food and water intake, and to collect urine and feces. Serum and urinary Mg2+ concentrations were determined and mRNA expression of magnesiotropic genes was determined in kidney and distal colon using RT-qPCR. Db/db mice had significantly lower serum Mg2+ levels than db/m mice. Mild hypermagnesuria was observed in the db/db mice at two weeks, but not at four weeks. Metformin-treatment had no effect on the serum Mg2+ concentration and on the urinary Mg2+ excretion. Both in kidney and distal colon of db/db mice, there was a compensatory upregulation in the mRNA expression of magnesiotropic genes, such as transient receptor potential melastatin 6 (Trpm6), whereas metformin treatment did not affect gene expression levels. In conclusion, we show that T2D causes hypomagnesemia and that metformin treatment has no effect on Mg2+ homeostasis in mice.
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15
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Akhtar MJ, Ahamed M, Alhadlaq HA, Alrokayan SA. MgO nanoparticles cytotoxicity caused primarily by GSH depletion in human lung epithelial cells. J Trace Elem Med Biol 2018; 50:283-290. [PMID: 30262293 DOI: 10.1016/j.jtemb.2018.07.016] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Revised: 07/17/2018] [Accepted: 07/20/2018] [Indexed: 12/14/2022]
Abstract
Bio-response of magnesium oxide nanoparticles (MgO NPs) is emerging, obviously, with a conflicting flavor. This study evaluates the underlying mechanism of bio-responses of MgO NPs in human lung epithelial (A549) cell. TEM size of NPs was 40-50 nm and cuboidal in shape. EDS data showed no detectable impurity. Zeta potential of MgO NPs suggested a fair dispersion in complete culture media and in PBS. MgO NPs induced a concentration dependent cytotoxicity when measured by MTT and NRU. MgO NPs induced cytotoxicity strongly correlated with intracellular depletion of antioxidant GSH. MgO NPs did not induce concentration dependent ROS. All live treatment conditions caused autophagy, a survival mechanism when deprived of nutrients and antioxidant. At highest cytotoxic concentration of MgO NPs, there was significant elevation in MMP and caspase-3 activity. GSH depletion mediated autophagy failure lead to MgO NPs induced death at higher concentrations that might have potentiated by induced ROS. This study suggested a mechanism of cytotoxicity caused by MgO NPs that was primarily dependent on GSH depletion, and ROS induction played secondary role in toxicity. Significantly higher toxicity observed for MgO NPs in comparison to Mg salt clearly indicated the involvement of nanoparticulate form in toxicity.
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Affiliation(s)
- Mohd Javed Akhtar
- King Abdullah Institute for Nanotechnology, King Saud University, Riyadh 11451, Saudi Arabia.
| | - Maqusood Ahamed
- King Abdullah Institute for Nanotechnology, King Saud University, Riyadh 11451, Saudi Arabia
| | - Hisham A Alhadlaq
- Department of Physics and Astronomy, College of Science, King Saud University, Riyadh 11451, Saudi Arabia; King Abdullah Institute for Nanotechnology, King Saud University, Riyadh 11451, Saudi Arabia
| | - Salman A Alrokayan
- Research Chair for Biomedical Applications of Nanomaterials, Biochemistry Department, College of Science, Building 5, PO Box 2455, King Saud University, Riyadh, Saudi Arabia
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16
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SLC41A1 is essential for magnesium homeostasis in vivo. Pflugers Arch 2018; 471:845-860. [PMID: 30417250 PMCID: PMC6533229 DOI: 10.1007/s00424-018-2234-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Revised: 11/01/2018] [Accepted: 11/04/2018] [Indexed: 01/19/2023]
Abstract
Solute carrier family 41 member A1 (SLC41A1) has been suggested to mediate magnesium (Mg2+) transport by several in vitro studies. However, the physiological function of SLC41A1 remains to be elucidated. In this study, cellular Mg2+ transport assays combined with zebrafish slc41a1 knockdown experiments were performed to disclose SLC41A1 function and its physiological relevance. The gene slc41a1 is ubiquitously expressed in zebrafish tissues and is regulated by water and dietary Mg2+ availability. Knockdown of slc41a1 in zebrafish larvae grown in a Mg2+-free medium resulted in a unique phenotype characterized by a decrease in zebrafish Mg content. This decrease shows that SLC41A1 is required to maintain Mg2+ balance and its dysfunction results in renal Mg2+ wasting in zebrafish larvae. Importantly, the Mg content of the larvae is rescued when mouse SLC41A1 is expressed in slc41a1-knockdown zebrafish. Conversely, expression of mammalian SLC41A1-p.Asp262Ala, harboring a mutation in the ion-conducting SLC41A1 pore, did not reverse the renal Mg2+ wasting. 25Mg2+ transport assays in human embryonic kidney 293 (HEK293) cells overexpressing SLC41A1 demonstrated that SLC41A1 mediates cellular Mg2+ extrusion independently of sodium (Na+). In contrast, SLC41A1-p.Asp262Ala expressing HEK293 cells displayed similar Mg2+ extrusion activities than control (mock) cells. In polarized Madin-Darby canine kidney cells, SLC41A1 localized to the basolateral cell membrane. Our results demonstrate that SLC41A1 facilitates renal Mg2+ reabsorption in the zebrafish model. Furthermore, our data suggest that SLC41A1 mediates both Mg2+ uptake and extrusion.
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17
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Nie M, Bal MS, Liu J, Yang Z, Rivera C, Wu XR, Hoenderop JGJ, Bindels RJM, Marciano DK, Wolf MTF. Uromodulin regulates renal magnesium homeostasis through the ion channel transient receptor potential melastatin 6 (TRPM6). J Biol Chem 2018; 293:16488-16502. [PMID: 30139743 DOI: 10.1074/jbc.ra118.003950] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Revised: 08/21/2018] [Indexed: 12/15/2022] Open
Abstract
Up to 15% of the population have mild to moderate chronic hypomagnesemia, which is associated with type 2 diabetes mellitus, hypertension, metabolic syndrome, and chronic kidney disease. The kidney is the key organ for magnesium homeostasis, but our understanding of renal magnesium regulation is very limited. Uromodulin (UMOD) is the most abundant urinary protein in humans, and here we report that UMOD has a role in renal magnesium homeostasis. Umod-knockout (Umod -/-) mice excreted more urinary magnesium than WT mice and displayed up-regulation of genes promoting magnesium absorption. The majority of magnesium is absorbed in the thick ascending limb. However, both mouse strains responded similarly to the diuretic agent furosemide, indicating appropriate function of the thick ascending limb in the Umod -/- mice. Magnesium absorption is fine-tuned in the distal convoluted tubule (DCT) via the apical magnesium channel transient receptor potential melastatin 6 (TRPM6). We observed decreased apical Trpm6 staining in the DCT of Umod -/- mice. Applying biotinylation assays and whole-cell patch-clamp recordings, we found that UMOD enhances TRPM6 cell-surface abundance and current density from the extracellular space. UMOD physically interacted with TRPM6 and thereby impaired dynamin-dependent TRPM6 endocytosis. WT mice fed a low-magnesium diet had an increased urinary UMOD secretion compared with the same mice on a regular diet. Our results suggest that increased urinary UMOD secretion in low-magnesium states reduces TRPM6 endocytosis and thereby up-regulates TRPM6 cell-surface abundance to defend against further urinary magnesium losses.
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Affiliation(s)
| | | | - Jie Liu
- From the Departments of Pediatrics and
| | - Zhufeng Yang
- Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas 75390
| | | | - Xue-Ru Wu
- the Departments of Urology and Pathology, New York University School of Medicine, New York, New York 10016, and
| | - Joost G J Hoenderop
- the Department of Physiology, Radboud Center for Molecular Life Sciences, Radboud University Medical Centre, 6525 GA Nijmegen, The Netherlands
| | - René J M Bindels
- the Department of Physiology, Radboud Center for Molecular Life Sciences, Radboud University Medical Centre, 6525 GA Nijmegen, The Netherlands
| | - Denise K Marciano
- Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas 75390
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18
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Kostov K, Halacheva L. Role of Magnesium Deficiency in Promoting Atherosclerosis, Endothelial Dysfunction, and Arterial Stiffening as Risk Factors for Hypertension. Int J Mol Sci 2018; 19:E1724. [PMID: 29891771 PMCID: PMC6032400 DOI: 10.3390/ijms19061724] [Citation(s) in RCA: 88] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Revised: 06/05/2018] [Accepted: 06/08/2018] [Indexed: 02/07/2023] Open
Abstract
Arterial hypertension is a disease with a complex pathogenesis. Despite considerable knowledge about this socially significant disease, the role of magnesium deficiency (MgD) as a risk factor is not fully understood. Magnesium is a natural calcium antagonist. It potentiates the production of local vasodilator mediators (prostacyclin and nitric oxide) and alters vascular responses to a variety of vasoactive substances (endothelin-1, angiotensin II, and catecholamines). MgD stimulates the production of aldosterone and potentiates vascular inflammatory response, while expression/activity of various antioxidant enzymes (glutathione peroxidase, superoxide dismutase, and catalase) and the levels of important antioxidants (vitamin C, vitamin E, and selenium) are decreased. Magnesium balances the effects of catecholamines in acute and chronic stress. MgD may be associated with the development of insulin resistance, hyperglycemia, and changes in lipid metabolism, which enhance atherosclerotic changes and arterial stiffness. Magnesium regulates collagen and elastin turnover in the vascular wall and matrix metalloproteinase activity. Magnesium helps to protect the elastic fibers from calcium deposition and maintains the elasticity of the vessels. Considering the numerous positive effects on a number of mechanisms related to arterial hypertension, consuming a healthy diet that provides the recommended amount of magnesium can be an appropriate strategy for helping control blood pressure.
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Affiliation(s)
- Krasimir Kostov
- Department of Pathophysiology, Medical University-Pleven, 1 Kliment Ohridski Str., 5800 Pleven, Bulgaria.
| | - Lyudmila Halacheva
- Department of Physiology, Medical University-Pleven, 1 Kliment Ohridski Str., 5800 Pleven, Bulgaria.
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19
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Longitudinal Study of the Role of Epidermal Growth Factor on the Fractional Excretion of Magnesium in Children: Effect of Calcineurin Inhibitors. Nutrients 2018; 10:nu10060677. [PMID: 29861470 PMCID: PMC6024309 DOI: 10.3390/nu10060677] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Revised: 05/17/2018] [Accepted: 05/21/2018] [Indexed: 01/16/2023] Open
Abstract
BACKGROUND It was shown in animal models and adults that the epidermal growth factor (EGF) is involved in the pathophysiology of calcineurin inhibitor (CNI) induced renal magnesium loss. In children, however, the exact mechanism remains unclear, which was set as the purpose of the present study. METHODS Children with nephrotic syndrome and renal transplant children treated with CNI (n = 50) and non-CNI treated children (n = 46) were included in this study. Urine and serum samples were collected at three time points to determine magnesium, creatinine, and EGF. The magnesium intake was calculated from a food frequency questionnaire. RESULTS Serum Mg2+ and urinary EGF/creatinine were significantly lower in the CNI treated children, with significantly more CNI-treated children developing hypomagnesaemia. In the latter patients, the fractional excretion of magnesium (FE Mg2+) was significantly higher. Urinary EGF, age, renal function, and serum magnesium were independent predictors of the FE Mg2+. Only 29% of the children reached the recommended daily intake of magnesium. The magnesium intake did not differ between hypomagnesemic and normomagnesemic patients and was not a predictor of the FE Mg2+. CONCLUSIONS In CNI-treated children who developed hypomagnesemia, the FE Mg2+ was increased. The urinary EGF concentration, age, and renal function are independent predictors of the FE Mg2+.
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20
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Oliveira B, Cunningham J, Walsh SB. Magnesium Balance in Chronic and End-Stage Kidney Disease. Adv Chronic Kidney Dis 2018; 25:291-295. [PMID: 29793669 DOI: 10.1053/j.ackd.2018.01.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Revised: 01/05/2018] [Accepted: 01/22/2018] [Indexed: 11/11/2022]
Abstract
This article explores the effects of CKD and end-stage kidney disease on magnesium balance. In CKD, there is decreased glomerular filtration of magnesium. Decreased tubular reabsorption can compensate to a degree, but once CKD stage 4 is reached there is a tendency toward hypermagnesemia. In dialysis, magnesium balance is dependent on the constituents of the dialysate that the blood is exposed to. The concentration of dialysate magnesium is just one of the factors that need to be considered. During transplantation, there are particular effects of immunosuppressants that can affect the magnesium balance and need to be considered by the clinician.
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22
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Mora-Pinzon MC, Trentham-Dietz A, Gangnon RE, Adams SV, Hampton JM, Burnside E, Shafer MM, Newcomb PA. Urinary Magnesium and Other Elements in Relation to Mammographic Breast Density, a Measure of Breast Cancer Risk. Nutr Cancer 2018. [PMID: 29537902 DOI: 10.1080/01635581.2018.1446094] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
PURPOSE Heavy metals and other elements may act as breast carcinogens due to estrogenic activity. We investigated associations between urine concentrations of a panel of elements and breast density. METHODS Mammographic density categories were abstracted from radiology reports of 725 women aged 40-65 yr in the Avon Army of Women. A panel of 27 elements was quantified in urine using high resolution magnetic sector inductively coupled plasma mass spectrometry. We applied LASSO (least absolute shrinkage and selection operator) logistic regression to the 27 elements and calculated odds ratios (OR) and 95% confidence intervals (CI) for dense vs. nondense breasts, adjusting for potential confounders. RESULTS Of the 27 elements, only magnesium (Mg) was selected into the optimal regression model. The odds ratio for dense breasts associated with doubling the Mg concentration was 1.24 (95% CI 1.03-1.49). Doubling the calcium-to-magnesium ratio was inversely associated with dense breasts (OR 0.83, 95% CI 0.70-0.98). CONCLUSIONS Our cross-sectional study found that higher levels of urinary magnesium were associated with greater breast density. Prospective studies are needed to confirm whether magnesium as evaluated in urine is prospectively associated with breast density and, more importantly, breast cancer.
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Affiliation(s)
- Maria C Mora-Pinzon
- a School of Medicine and Public Health, University of Wisconsin-Madison , Madison , Wisconsin , USA
| | - Amy Trentham-Dietz
- b Carbone Cancer Center and Department of Population Health Sciences , School of Medicine and Public Health, University of Wisconsin-Madison , Madison , Wisconsin , USA
| | - Ronald E Gangnon
- b Carbone Cancer Center and Department of Population Health Sciences , School of Medicine and Public Health, University of Wisconsin-Madison , Madison , Wisconsin , USA.,c Department of Biostatistics and Medical Informatics , School of Medicine and Public Health, University of Wisconsin-Madison , Madison , Wisconsin , USA
| | - Scott V Adams
- d Fred Hutchinson Cancer Research Center , Seattle , Washington , USA
| | - John M Hampton
- b Carbone Cancer Center and Department of Population Health Sciences , School of Medicine and Public Health, University of Wisconsin-Madison , Madison , Wisconsin , USA
| | - Elizabeth Burnside
- b Carbone Cancer Center and Department of Population Health Sciences , School of Medicine and Public Health, University of Wisconsin-Madison , Madison , Wisconsin , USA.,e Department of Radiology , School of Medicine and Public Health, University of Wisconsin-Madison , Madison , Wisconsin , USA
| | - Martin M Shafer
- f Wisconsin State Laboratory of Hygiene , Madison , Wisconsin , USA
| | - Polly A Newcomb
- d Fred Hutchinson Cancer Research Center , Seattle , Washington , USA.,g Department of Epidemiology , School of Public Health, University of Washington , Seattle , Washington , USA
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23
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Common single nucleotide polymorphisms in transient receptor potential melastatin type 6 increase the risk for proton pump inhibitor-induced hypomagnesemia: a case-control study. Pharmacogenet Genomics 2017; 27:83-88. [PMID: 27926584 DOI: 10.1097/fpc.0000000000000259] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
OBJECTIVE Proton pump inhibitors (PPIs) are effective drugs for the treatment of gastric acid-related disorders. Serious adverse events are rare for PPIs, but recent data suggest that PPIs cause hypomagnesemia. The aim of this study was to estimate the frequency of PPI-induced hypomagnesemia and to define the risk factors for its development. MATERIALS AND METHODS A total of 133 chronic users of PPIs were enrolled and patients were distinguished on the basis of their serum Mg concentrations. Common single nucleotide polymorphisms (SNPs) in the candidate gene, transient receptor potential melastatin type 6 (TRPM6), were screened. RESULTS Seventeen out of 133 patients had PPI-induced hypomagnesemia. The duration of PPI use was longer in those with hypomagnesemia (7.7 vs. 5.2 years). Two common SNPs in TRPM6 (rs3750425 and rs2274924) increased the risk for PPI-induced hypomagnesemia by 5.8-fold. CONCLUSION We found hypomagnesemia in 13% of PPI users. SNPs in TRPM6 drive the risk of developing hypomagnesemia during chronic PPI use.
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24
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Abstract
PURPOSE OF REVIEW Magnesium (Mg) imbalances are frequently overlooked. Hypermagnesemia usually occurs in preeclamptic women after Mg therapy or in end-stage renal disease patients, whereas hypomagnesemia is more common with a prevalence of up to 15% in the general population. Increasing evidence points toward a role for mild-to-moderate chronic hypomagnesemia in the pathogenesis of hypertension, type 2 diabetes mellitus, and metabolic syndrome. RECENT FINDINGS The kidneys are the major regulator of total body Mg homeostasis. Over the last decade, the identification of the responsible genes in rare genetic disorders has enhanced our understanding of how the kidney handles Mg. The different genetic disorders and medications contributing to abnormal Mg homeostasis are reviewed. SUMMARY As dysfunctional Mg homeostasis contributes to the development of many common human disorders, serum Mg deserves closer monitoring. Hypomagnesemic patients may be asymptomatic or may have mild symptoms. In severe hypomagnesemia, patients may present with neurological symptoms such as seizures, spasms, or cramps. Renal symptoms include nephrocalcinosis and impaired renal function. Most conditions affect tubular Mg reabsorption by disturbing the lumen-positive potential in the thick ascending limb or the negative membrane potential in the distal convoluted tubule.
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25
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Saraç M, Önalan E, Bakal Ü, Tartar T, Aydın M, Orman A, Tektemur A, Taşkın E, Erol FS, Kazez A. Magnesium-permeable TRPM6 polymorphisms in patients with meningomyelocele. SPRINGERPLUS 2016; 5:1703. [PMID: 27757375 PMCID: PMC5047867 DOI: 10.1186/s40064-016-3395-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Accepted: 09/26/2016] [Indexed: 11/10/2022]
Abstract
BACKGROUND To evaluate whether there is an association between single nucleotide polymorphisms in magnesium-permeable TRPM6 ion channel and development of meningomyelocele (MMC). Therefore, we examined a total of 150 children with MMC, along with age- and gender-matched controls. DNA collected from whole blood was analyzed for the presence of two polymorphisms, rs2274924 (A > G; K1579E; Leu1579Glu) and rs3750425 (G > A; Val1393Ile), in TRPM6. Serum Mg2+ and calcium levels were also examined. RESULTS A statistically significant difference in the distribution of rs2274924 genotypes (p = 0.049) was observed between the groups. Decreases in the AA genotype, and increases in the AG heterozygous genotype were also detected in the study group. The distribution of polymorphisms in the rs3750425 genotype and alleles was not statistically different between groups. Serum Mg2+ levels were lower in the GG genotype of rs3750425 compared with the GA and AA genotypes (p = 0.003). CONCLUSIONS A statistically significant difference in rs3750425 genotypes was observed between the patients with MMC and the controls, which corresponded to lower serum Mg2+ concentrations in these patients. Taken together, these results suggest that genetic variations in the Mg2+-permeable TRPM6 ion channel may play a role in the etiopathogenesis of MMC during embryonic development.
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Affiliation(s)
- Mehmet Saraç
- Department of Pediatric Surgery, Firat University Medical Faculty, 23119 Elazig, Turkey
| | - Ebru Önalan
- Department of Medical Biology, Firat University Medical Faculty, Elazig, Turkey
| | - Ünal Bakal
- Department of Pediatric Surgery, Firat University Medical Faculty, 23119 Elazig, Turkey
| | - Tugay Tartar
- Department of Pediatric Surgery, Firat University Medical Faculty, 23119 Elazig, Turkey
| | - Mustafa Aydın
- Department of Neonatology, Firat University Medical Faculty, Elazig, Turkey
| | - Ayşen Orman
- Department of Neonatology, Firat University Medical Faculty, Elazig, Turkey
| | - Ahmet Tektemur
- Department of Medical Biology, Firat University Medical Faculty, Elazig, Turkey
| | - Erdal Taşkın
- Department of Neonatology, Firat University Medical Faculty, Elazig, Turkey
| | - Fatih Serhat Erol
- Department of Neurosurgery, Firat University Medical Faculty, Elazig, Turkey
| | - Ahmet Kazez
- Department of Pediatric Surgery, Firat University Medical Faculty, 23119 Elazig, Turkey
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26
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Abstract
Over the past decades, hypomagnesemia (serum Mg(2+) <0.7 mmol/L) has been strongly associated with type 2 diabetes mellitus (T2DM). Patients with hypomagnesemia show a more rapid disease progression and have an increased risk for diabetes complications. Clinical studies demonstrate that T2DM patients with hypomagnesemia have reduced pancreatic β-cell activity and are more insulin resistant. Moreover, dietary Mg(2+) supplementation for patients with T2DM improves glucose metabolism and insulin sensitivity. Intracellular Mg(2+) regulates glucokinase, KATP channels, and L-type Ca(2+) channels in pancreatic β-cells, preceding insulin secretion. Moreover, insulin receptor autophosphorylation is dependent on intracellular Mg(2+) concentrations, making Mg(2+) a direct factor in the development of insulin resistance. Conversely, insulin is an important regulator of Mg(2+) homeostasis. In the kidney, insulin activates the renal Mg(2+) channel transient receptor potential melastatin type 6 that determines the final urinary Mg(2+) excretion. Consequently, patients with T2DM and hypomagnesemia enter a vicious circle in which hypomagnesemia causes insulin resistance and insulin resistance reduces serum Mg(2+) concentrations. This Perspective provides a systematic overview of the molecular mechanisms underlying the effects of Mg(2+) on insulin secretion and insulin signaling. In addition to providing a review of current knowledge, we provide novel directions for future research and identify previously neglected contributors to hypomagnesemia in T2DM.
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Affiliation(s)
- Lisanne M M Gommers
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Nijmegen Medical Center, Nijmegen, the Netherlands
| | - Joost G J Hoenderop
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Nijmegen Medical Center, Nijmegen, the Netherlands
| | - René J M Bindels
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Nijmegen Medical Center, Nijmegen, the Netherlands
| | - Jeroen H F de Baaij
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Nijmegen Medical Center, Nijmegen, the Netherlands Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, U.K.
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27
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Tomilin V, Mamenko M, Zaika O, Pochynyuk O. Role of renal TRP channels in physiology and pathology. Semin Immunopathol 2015; 38:371-83. [PMID: 26385481 DOI: 10.1007/s00281-015-0527-z] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Accepted: 09/04/2015] [Indexed: 01/05/2023]
Abstract
Kidneys critically contribute to the maintenance of whole-body homeostasis by governing water and electrolyte balance, controlling extracellular fluid volume, plasma osmolality, and blood pressure. Renal function is regulated by numerous systemic endocrine and local mechanical stimuli. Kidneys possess a complex network of membrane receptors, transporters, and ion channels which allows responding to this wide array of signaling inputs in an integrative manner. Transient receptor potential (TRP) channel family members with diverse modes of activation, varied permeation properties, and capability to integrate multiple downstream signals are pivotal molecular determinants of renal function all along the nephron. This review summarizes experimental data on the role of TRP channels in a healthy mammalian kidney and discusses their involvement in renal pathologies.
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Affiliation(s)
- Viktor Tomilin
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center at Houston, 6431 Fannin, Houston, TX, 77030, USA.,Institute of Cytology, Russian Academy of Sciences, St. Petersburg, Russian Federation
| | - Mykola Mamenko
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center at Houston, 6431 Fannin, Houston, TX, 77030, USA
| | - Oleg Zaika
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center at Houston, 6431 Fannin, Houston, TX, 77030, USA
| | - Oleh Pochynyuk
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center at Houston, 6431 Fannin, Houston, TX, 77030, USA.
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28
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Blanchard MG, Kittikulsuth W, Nair AV, de Baaij JHF, Latta F, Genzen JR, Kohan DE, Bindels RJM, Hoenderop JGJ. Regulation of Mg2+ Reabsorption and Transient Receptor Potential Melastatin Type 6 Activity by cAMP Signaling. J Am Soc Nephrol 2015; 27:804-13. [PMID: 26150606 DOI: 10.1681/asn.2014121228] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Accepted: 05/21/2015] [Indexed: 01/14/2023] Open
Abstract
The transient receptor potential melastatin type 6 (TRPM6) epithelial Mg(2+) channels participate in transcellular Mg(2+) transport in the kidney and intestine. Previous reports suggested a hormonal cAMP-dependent regulation of Mg(2+) reabsorption in the kidney. The molecular details of this process are, however, unknown. Adenylate cyclase 3 (Adcy3) has been shown to colocalize with the Na(+)/Cl(-) cotransporter, a marker of the distal convoluted segment of the kidney, the principal site of TRPM6 expression. Given the critical role of TRPM6 in Mg(2+) reabsorption, an inducible kidney-specific Adcy3 deletion mouse model was characterized for blood and urinary electrolyte disturbances under a normal--and low--Mg(2+) diet. Increased urinary Mg(2+) wasting and Trpm6 mRNA levels were observed in the urine and kidney of Adcy3-deleted animals compared with wild-type controls. Serum Mg(2+) concentration was significantly lower in Adcy3-deleted animals at day 7 on the low Mg(2+) diet. Using patch clamp electrophysiology, cell surface biotinylation, and total internal reflection fluorescence live cell imaging of transfected HEK293 cells, we demonstrated that cAMP signaling rapidly potentiates TRPM6 activity by promoting TRPM6 accumulation at the plasma membrane and increasing its single-channel conductance. Comparison of electrophysiological data from cells expressing the phosphorylation-deficient S1252A or phosphomimetic S1252D TRPM6 mutants suggests that phosphorylation at this intracellular residue participates in the observed stimulation of channel activity. Altogether, these data support a physiologically relevant magnesiotropic role of cAMP signaling in the kidney by a direct stimulatory action of protein kinase A on the plasma membrane trafficking and function of TRPM6 ion channels.
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Affiliation(s)
- Maxime G Blanchard
- Department of Physiology, Radboud University Medical Center, Nijmegen, The Netherlands
| | | | - Anil V Nair
- Department of Physiology, Radboud University Medical Center, Nijmegen, The Netherlands; Center for Systems Biology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
| | - Jeroen H F de Baaij
- Department of Physiology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Femke Latta
- Department of Physiology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Jonathan R Genzen
- Department of Pathology, School of Medicine, University of Utah, Salt Lake City, Utah; and
| | | | - René J M Bindels
- Department of Physiology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Joost G J Hoenderop
- Department of Physiology, Radboud University Medical Center, Nijmegen, The Netherlands;
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Blanchard MG, de Baaij JHF, Verkaart SAJ, Lameris AL, Basmadjian C, Zhao Q, Désaubry L, Bindels RJM, Hoenderop JGJ. Flavaglines Stimulate Transient Receptor Potential Melastatin Type 6 (TRPM6) Channel Activity. PLoS One 2015; 10:e0119028. [PMID: 25774985 PMCID: PMC4361557 DOI: 10.1371/journal.pone.0119028] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Accepted: 01/01/2015] [Indexed: 11/19/2022] Open
Abstract
Magnesium (Mg2+) is essential for enzymatic activity, brain function and muscle contraction. Blood Mg2+ concentrations are tightly regulated between 0.7 and 1.1 mM by Mg2+ (re)absorption in kidney and intestine. The apical entry of Mg2+ in (re)absorbing epithelial cells is mediated by the transient receptor potential melastatin type 6 (TRPM6) ion channel. Here, flavaglines are described as a novel class of stimulatory compounds for TRPM6 activity. Flavaglines are a group of natural and synthetic compounds that target the ubiquitously expressed prohibitins and thereby affect cellular signaling. By whole-cell patch clamp analyses, it was demonstrated that nanomolar concentrations of flavaglines increases TRPM6 activity by ∼2 fold. The stimulatory effects were dependent on the presence of the alpha-kinase domain of TRPM6, but did not require its phosphotransferase activity. Interestingly, it was observed that two natural occurring TRPM6 mutants with impaired insulin-sensitivity, TRPM6-p.Val1393Ile and TRPM6-p.Lys1584Glu, are not sensitive to flavagline stimulation. In conclusion, we have identified flavaglines as potent activators of TRPM6 activity. Our results suggest that flavaglines stimulate TRPM6 via the insulin receptor signaling pathway.
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Affiliation(s)
- Maxime G. Blanchard
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Jeroen H. F. de Baaij
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Sjoerd A. J. Verkaart
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Anke L. Lameris
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Christine Basmadjian
- Laboratory of Therapeutic Innovation (UMR7200), CNRS-University of Strasbourg, Faculty of Pharmacy, Illkirch, France
| | - Qian Zhao
- Laboratory of Therapeutic Innovation (UMR7200), CNRS-University of Strasbourg, Faculty of Pharmacy, Illkirch, France
| | - Laurent Désaubry
- Laboratory of Therapeutic Innovation (UMR7200), CNRS-University of Strasbourg, Faculty of Pharmacy, Illkirch, France
| | - René J. M. Bindels
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Joost G. J. Hoenderop
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
- * E-mail:
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de Baaij JHF, Hoenderop JGJ, Bindels RJM. Magnesium in man: implications for health and disease. Physiol Rev 2015; 95:1-46. [PMID: 25540137 DOI: 10.1152/physrev.00012.2014] [Citation(s) in RCA: 862] [Impact Index Per Article: 95.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Magnesium (Mg(2+)) is an essential ion to the human body, playing an instrumental role in supporting and sustaining health and life. As the second most abundant intracellular cation after potassium, it is involved in over 600 enzymatic reactions including energy metabolism and protein synthesis. Although Mg(2+) availability has been proven to be disturbed during several clinical situations, serum Mg(2+) values are not generally determined in patients. This review aims to provide an overview of the function of Mg(2+) in human health and disease. In short, Mg(2+) plays an important physiological role particularly in the brain, heart, and skeletal muscles. Moreover, Mg(2+) supplementation has been shown to be beneficial in treatment of, among others, preeclampsia, migraine, depression, coronary artery disease, and asthma. Over the last decade, several hereditary forms of hypomagnesemia have been deciphered, including mutations in transient receptor potential melastatin type 6 (TRPM6), claudin 16, and cyclin M2 (CNNM2). Recently, mutations in Mg(2+) transporter 1 (MagT1) were linked to T-cell deficiency underlining the important role of Mg(2+) in cell viability. Moreover, hypomagnesemia can be the consequence of the use of certain types of drugs, such as diuretics, epidermal growth factor receptor inhibitors, calcineurin inhibitors, and proton pump inhibitors. This review provides an extensive and comprehensive overview of Mg(2+) research over the last few decades, focusing on the regulation of Mg(2+) homeostasis in the intestine, kidney, and bone and disturbances which may result in hypomagnesemia.
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Affiliation(s)
- Jeroen H F de Baaij
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Joost G J Hoenderop
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - René J M Bindels
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
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31
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Abstract
PURPOSE OF REVIEW The tight control of blood magnesium (Mg) levels is of central importance for numerous physiological processes. A persistent low Mg status (hypomagnesemia) is associated with severe health risks and is involved in the pathogenesis of type 2 diabetes mellitus, osteoporosis, asthma, and heart and vascular diseases. The current view has expanded significantly as a result of the identification of novel genes and regulatory pathways involved in hypomagnesemic disorders. This review aims to give an up-to-date overview of transient receptor potential melastatin 6 (TRPM6) regulation and its role in the maintenance of Mg homeostasis. RECENT FINDINGS The epithelial Mg channel TRPM6 is considered to be the Mg entry pathway in the distal convoluted tubule of the kidney, where it functions as gatekeeper for controlling the body's Mg balance. Various factors and hormones contribute not only to the function, but also to the dysregulation of TRPM6, which has a substantial impact on renal Mg handling. Recent genetic and molecular studies have further elucidated the signaling processes of epithelial Mg transport, including their effect on the expression and function of TRPM6. SUMMARY Knowledge of TRPM6 functioning is of vital importance to decipher its role in Mg handling and will, in particular, provide a molecular basis for achieving a better understanding of Mg mal(re)absorption and hence systemic Mg balance.
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32
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Differential mRNA expression and glucocorticoid-mediated regulation of TRPM6 and TRPM7 in the heart and kidney throughout murine pregnancy and development. PLoS One 2015; 10:e0117978. [PMID: 25692682 PMCID: PMC4333289 DOI: 10.1371/journal.pone.0117978] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2014] [Accepted: 01/06/2015] [Indexed: 11/19/2022] Open
Abstract
The transient receptor potential (TRP) channels TRPM6 and TRPM7 are critically involved in maintaining whole body and cellular Mg2+ homeostasis and ensuring the normal function of organs such as the heart and kidney. However, we do not know how the expression of TRPM6 and TPRM7 in these organs changes throughout fetal development and adult life, and whether this expression can be hormonally regulated. This study determined the ontogeny of TRPM6 and TRPM7 mRNA expression from mid-gestation through to adulthood in the mouse. In a second series of experiments, we examined how maternal administration of the glucocorticoids corticosterone and dexamethasone between embryonic days 12.5–15 affected TRPM6 and TRPM7 channel mRNA expression in the mother and fetus. Whilst renal TRPM7 expression was relatively constant throughout development, renal TRPM6 expression was markedly upregulated after birth. In contrast, cardiac TRPM7 expression was 2–4 fold higher in the fetus than in the adult. Surprisingly, TRPM6 expression was detected in the fetal heart (qPCR and in situ hybridization). Glucocorticoid administration during gestation increased fetal cardiac expression of both channels without affecting renal expression. In contrast, in the dam renal TRPM6 and TRPM7 expression was increased by glucocorticoids with no change in the cardiac channel expression. These data suggest that TRPM6 and TRPM7 channels are important in organogenesis, and that elevated maternal glucocorticoid levels can alter the expression of these channels. This suggests that perturbations in hormonal regulatory systems during pregnancy may adversely impact upon normal fetal development, at least in part by altering expression of TRPM channels.
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Abstract
The distal convoluted tubule (DCT) is a short nephron segment, interposed between the macula densa and collecting duct. Even though it is short, it plays a key role in regulating extracellular fluid volume and electrolyte homeostasis. DCT cells are rich in mitochondria, and possess the highest density of Na+/K+-ATPase along the nephron, where it is expressed on the highly amplified basolateral membranes. DCT cells are largely water impermeable, and reabsorb sodium and chloride across the apical membrane via electroneurtral pathways. Prominent among this is the thiazide-sensitive sodium chloride cotransporter, target of widely used diuretic drugs. These cells also play a key role in magnesium reabsorption, which occurs predominantly, via a transient receptor potential channel (TRPM6). Human genetic diseases in which DCT function is perturbed have provided critical insights into the physiological role of the DCT, and how transport is regulated. These include Familial Hyperkalemic Hypertension, the salt-wasting diseases Gitelman syndrome and EAST syndrome, and hereditary hypomagnesemias. The DCT is also established as an important target for the hormones angiotensin II and aldosterone; it also appears to respond to sympathetic-nerve stimulation and changes in plasma potassium. Here, we discuss what is currently known about DCT physiology. Early studies that determined transport rates of ions by the DCT are described, as are the channels and transporters expressed along the DCT with the advent of molecular cloning. Regulation of expression and activity of these channels and transporters is also described; particular emphasis is placed on the contribution of genetic forms of DCT dysregulation to our understanding.
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Affiliation(s)
- James A McCormick
- Division of Nephrology & Hypertension, Oregon Health & Science University, & VA Medical Center, Portland, Oregon, United States
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34
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Hill M, Dušková M, Stárka L. Dehydroepiandrosterone, its metabolites and ion channels. J Steroid Biochem Mol Biol 2015; 145:293-314. [PMID: 24846830 DOI: 10.1016/j.jsbmb.2014.05.006] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2014] [Revised: 05/06/2014] [Accepted: 05/11/2014] [Indexed: 11/20/2022]
Abstract
This review is focused on the physiological and pathophysiological relevance of steroids influencing the activities of the central and peripheral nervous systems with regard to their concentrations in body fluids and tissues in various stages of human life like the fetal development or pregnancy. The data summarized in this review shows that DHEA and its unconjugated and sulfated metabolites are physiologically and pathophysiologically relevant in modulating numerous ion channels and participate in vital functions of the human organism. DHEA and its unconjugated and sulfated metabolites including 5α/β-reduced androstane steroids participate in various physiological and pathophysiological processes like the management of GnRH cyclic release, regulation of glandular and neurotransmitter secretions, maintenance of glucose homeostasis on one hand and insulin insensitivity on the other hand, control of skeletal muscle and smooth muscle activities including vasoregulation, promotion of tolerance to ischemia and other neuroprotective effects. In respect of prevalence of steroid sulfates over unconjugated steroids in the periphery and the opposite situation in the CNS, the sulfated androgens and androgen metabolites reach relevance in peripheral organs. The unconjugated androgens and estrogens are relevant in periphery and so much the more in the CNS due to higher concentrations of most unconjugated steroids in the CNS tissues than in circulation and peripheral organs. This article is part of a Special Issue entitled "Essential role of DHEA".
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Affiliation(s)
- M Hill
- Steroid Hormone Unit, Institute of Endocrinology, Národní třída 8, Prague 116 94, Praha 1, CZ 116 94, Czech Republic.
| | - M Dušková
- Steroid Hormone Unit, Institute of Endocrinology, Národní třída 8, Prague 116 94, Praha 1, CZ 116 94, Czech Republic.
| | - L Stárka
- Steroid Hormone Unit, Institute of Endocrinology, Národní třída 8, Prague 116 94, Praha 1, CZ 116 94, Czech Republic.
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35
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Toh JWT, Ong E, Wilson R. Hypomagnesaemia associated with long-term use of proton pump inhibitors. Gastroenterol Rep (Oxf) 2014; 3:243-53. [PMID: 25138239 PMCID: PMC4527261 DOI: 10.1093/gastro/gou054] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2014] [Accepted: 07/15/2014] [Indexed: 12/13/2022] Open
Abstract
Hypomagnesaemia and associated hypocalcaemia and hypoparathyroidism have been increasingly recognised as rare long-term side-effects of proton pump inhibitors (PPIs). The PPIs may inhibit active magnesium (Mg) absorption by interfering with transcellular transient receptor potential melastatin-6 and -7 (TRPM 6 and 7) channels. More recent cell culture studies have suggested concomitant inhibition of passive Mg absorption by omeprazole. After being treated with a range of PPIs, the four patients in our case series developed hypomagnesaemia, which responded to withdrawal of therapy and initiation of Mg replacement. Their clinical course and management demonstrate key aspects of hypomagnesaemia associated with long-term use of PPIs.
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Affiliation(s)
- James Wei Tatt Toh
- General Surgery, Liverpool Hospital, University of New South Wales, Liverpool, New South Wales, Australia,
| | - Evonne Ong
- University of New South Wales Clinical School, Liverpool, New South Wales, Australia and
| | - Robert Wilson
- Upper Gastrointestinal Surgery, Liverpool Hospital, University of New South Wales, Liverpool, New South Wales, Australia
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36
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Ayuk J, Gittoes NJL. Contemporary view of the clinical relevance of magnesium homeostasis. Ann Clin Biochem 2014; 51:179-88. [PMID: 24402002 DOI: 10.1177/0004563213517628] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Magnesium is one of the most abundant cations in the body and is essential for a wide variety of metabolically important reactions. Serum magnesium concentration is regulated by the balance between intestinal absorption and renal excretion. Hypomagnesaemia is relatively common, with an estimated prevalence in the general population ranging from 2.5 to 15%. It may result from inadequate magnesium intake, increased gastrointestinal or renal loss or redistribution from extracellular to intracellular space. Drug-induced hypomagnesaemia, particularly related to proton-pump inhibitor (PPI) therapy, is being increasingly recognized. Although most patients with hypomagnesaemia are asymptomatic, manifestations may include neuromuscular, cardiovascular and metabolic features. Due to the kidney's ability to increase fractional excretion to nearly 100% when the renal magnesium threshold is exceeded, clinically significant hypermagnesaemia is uncommon, generally occurring only in the setting of renal insufficiency and excessive magnesium intake. Symptoms include hypotension, nausea, facial flushing, ileus and flaccid muscle paralysis. In most cases, simply withdrawing exogenous magnesium is sufficient to restore normal magnesium concentrations, although occasionally administration of intravenous calcium or even dialysis may be required.
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Affiliation(s)
- John Ayuk
- Department of Endocrinology, Queen Elizabeth Hospital, Edgbaston, Birmingham, UK
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Abstract
TRPM6 is a bifunctional protein comprising a TRP cation channel segment covalently linked to an α-type serine/threonine protein kinase. TRPM6 is expressed in the intestinal and renal epithelial cells. Loss-of-function mutations in the human TRPM6 gene give rise to hypomagnesemia with secondary hypocalcemia (HSH), suggesting that the TRPM6 channel kinase plays a central role in systemic Mg(2+) homeostasis. In contrast, Trpm6 null mice show a delay in prenatal development, neural tube defects, and prenatal death. Possible functions of TRPM6 in prenatal and adult organisms will be discussed in this chapter.
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Affiliation(s)
- Vladimir Chubanov
- Walther-Straub-Institute for Pharmacology and Toxicology, Ludwig-Maximilians University Munich, Goethestrasse 33, Munich, 80336, Germany,
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38
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Non-genomic estrogen regulation of ion transport and airway surface liquid dynamics in cystic fibrosis bronchial epithelium. PLoS One 2013; 8:e78593. [PMID: 24223826 PMCID: PMC3817220 DOI: 10.1371/journal.pone.0078593] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2013] [Accepted: 09/20/2013] [Indexed: 11/26/2022] Open
Abstract
Male cystic fibrosis (CF) patients survive longer than females and lung exacerbations in CF females vary during the estrous cycle. Estrogen has been reported to reduce the height of the airway surface liquid (ASL) in female CF bronchial epithelium. Here we investigated the effect of 17β-estradiol on the airway surface liquid height and ion transport in normal (NuLi-1) and CF (CuFi-1) bronchial epithelial monolayers. Live cell imaging using confocal microscopy revealed that airway surface liquid height was significantly higher in the non-CF cells compared to the CF cells. 17β-estradiol (0.1–10 nM) reduced the airway surface liquid height in non-CF and CF cells after 30 min treatment. Treatment with the nuclear-impeded Estrogen Dendrimer Conjugate mimicked the effect of free estrogen by reducing significantly the airway surface liquid height in CF and non-CF cells. Inhibition of chloride transport or basolateral potassium recycling decreased the airway surface liquid height and 17β-estradiol had no additive effect in the presence of these ion transporter inhibitors. 17β-estradiol decreased bumetanide-sensitive transepithelial short-circuit current in non-CF cells and prevented the forskolin-induced increase in ASL height. 17β-estradiol stimulated an amiloride-sensitive transepithelial current and increased ouabain-sensitive basolateral short-circuit current in CF cells. 17β-estradiol increased PKCδ activity in CF and non-CF cells. These results demonstrate that estrogen dehydrates CF and non-CF ASL, and these responses to 17β-estradiol are non-genomic rather than involving the classical nuclear estrogen receptor pathway. 17β-estradiol acts on the airway surface liquid by inhibiting cAMP-mediated chloride secretion in non-CF cells and increasing sodium absorption via the stimulation of PKCδ, ENaC and the Na+/K+ATPase in CF cells.
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39
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Thuaud F, Ribeiro N, Nebigil CG, Désaubry L. Prohibitin ligands in cell death and survival: mode of action and therapeutic potential. ACTA ACUST UNITED AC 2013; 20:316-31. [PMID: 23521790 PMCID: PMC7111013 DOI: 10.1016/j.chembiol.2013.02.006] [Citation(s) in RCA: 154] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2012] [Revised: 01/31/2013] [Accepted: 02/06/2013] [Indexed: 12/21/2022]
Abstract
Prohibitins (PHBs) are scaffold proteins that modulate many signaling pathways controlling cell survival, metabolism, and inflammation. Several drugs that target PHBs have been identified and evaluated for various clinical applications. Preclinical and clinical studies indicate that these PHB ligands may be useful in oncology, cardiology, and neurology, as well as against obesity. This review covers the physiological role of PHBs in health and diseases and current developments concerning PHB ligands.
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Affiliation(s)
- Frédéric Thuaud
- Therapeutic Innovation Laboratory UMR 7200, CNRS/Université de Strasbourg, Faculté de Pharmacie, 67401 Illkirch Cedex, France
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40
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Kukkonen JP. Lipid signaling cascades of orexin/hypocretin receptors. Biochimie 2013; 96:158-65. [PMID: 23810911 DOI: 10.1016/j.biochi.2013.06.015] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2013] [Accepted: 06/18/2013] [Indexed: 11/18/2022]
Abstract
Orexins - orexin-A and orexin-B - are neuropeptides with significant role in regulation of fundamental physiological processes such as sleep-wakefulness cycle. Orexins act via G-protein-coupled OX1 and OX2 receptors, which are found, in addition to the central nervous system, also in a number of peripheral organs. Orexin receptors show high degree of signaling promiscuity. One particularly prominent way of signaling for these receptors is via phospholipase cascades, including the phospholipase C, phospholipase D and phospholipase A2 cascades, and also diacylglycerol lipase and phosphoinositide-3-kinase pathways. Most analyses have been performed in recombinant cells; there are indications of some of these cascades in native cells while the significance of other cascades remains to be shown. In this review, I present these pathways, their activation mechanisms and their physiological significance.
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Key Words
- 2-AG
- 2-arachidonoylglycerol
- AA
- CNS
- DAG
- DAG lipase
- DAGL
- DOG
- ERK
- Endocannabinoid
- G-protein-coupled receptor
- GPCR
- GPL
- Hypocretin
- IP(3)
- Ion fluxes
- KB-R7943
- MAFP
- N-acyl-phosphatidylethanolamine
- N-arachidonoylethanolamine
- NAPE
- NSCC
- OX(1)
- OX(2)
- Orexin
- PA
- PC
- PC-PLC
- PC-specific PLC
- PDK1
- PI
- PI3K
- PIP
- PIP(2)
- PIP(3)
- PIs
- PKB, PKC and PKD
- PLA(1), PLA(2), PLB, PLC and PLD
- Phospholipase
- TRP (channel)
- U73122
- a NCX inhibitor
- a PLC inhibitor
- a cPLA(2)α/ζ inhibitor
- anandamide
- arachidonic acid
- cPLA(2) and iPLA(2)
- central nervous system
- cytosolic (Ca(2+)-dependent) and intracellular (Ca(2+)-independent) PLA(2), respectively
- diacylglycerol
- dioctanoylglycerol
- extracellular signal-regulated kinase
- glycerophospholipid
- inositol-1,4,5-trisphosphate
- lyso(glycero)phospholipid
- lysoGPL
- lysoPA
- lysophosphatidic acid
- methyl arachidonyl fluorophosphonate
- non-selective cation channel
- orexin 1 receptor
- orexin 2 receptor
- phosphatidic acid
- phosphatidylcholine
- phosphatidylinositol
- phosphatidylinositol-3,4,5-trisphosphate
- phosphatidylinositol-4,5-bisphosphate
- phosphatidylinositolmonophosphate
- phosphatidylinositols (including differentially phosphorylated species PI, PIP, PIP(2) and PIP(3))
- phosphoinositide-3-kinase
- phosphoinositide-dependent kinase 1
- phospholipase A(1), A(2), B, C and D, respectively
- protein kinase B, C and D, respectively
- pyrrophenone
- transient receptor potential (channel)
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Affiliation(s)
- Jyrki P Kukkonen
- Biochemistry and Cell Biology, Department of Veterinary Biosciences, POB 66, FIN-00014, University of Helsinki, Finland.
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41
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Abstract
Mammalian cells tightly regulate cellular Mg(2+) content through a variety of transport and buffering mechanisms under the control of various hormones and cellular second messengers. The effect of these hormones and agents results in dynamic changes in the total content of Mg(2+) being transported across the cell membrane and redistributed within cellular compartments. The importance of maintaining proper cellular Mg(2+) content optimal for the activity of various cellular enzymes and metabolic cycles is underscored by the evidence that several diseases are characterized by a loss of Mg(2+) within specific tissues as a result of defective transport, hormonal stimulation, or metabolic impairment. This chapter will review the key mechanisms regulating cellular Mg(2+) homeostasis and their impairments under the most common diseases associated with Mg(2+) loss or deficiency.
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Affiliation(s)
- Andrea M P Romani
- Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH, 44106-4970, USA,
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42
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Wilmot B, Voruganti VS, Chang YPC, Fu Y, Chen Z, Taylor HA, Wilson JG, Gipson T, Shah VO, Umans JG, Flessner MF, Hitzemann R, Shuldiner AR, Comuzzie AG, McWeeney S, Zager PG, Maccluer JW, Cole SA, Cohen DM. Heritability of serum sodium concentration: evidence for sex- and ethnic-specific effects. Physiol Genomics 2011; 44:220-8. [PMID: 22186255 DOI: 10.1152/physiolgenomics.00153.2011] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Serum sodium concentration is the clinical index of systemic water balance. Although disordered water balance is common and morbid, little is known about genetic effects on serum sodium concentration at the population level. Prior studies addressed only participants of European descent and either failed to demonstrate significant heritability or showed only modest effect. We investigated heritability of serum sodium concentration in large cohorts reflecting a range of races/ethnicities, including the Framingham Heart Study (FHS, non-Hispanic Caucasian), the Heredity and Phenotype Intervention Heart Study (HAPI, Amish Caucasian), the Jackson Heart Study (JHS, African American), the Strong Heart Family Study (SHFS, American Indian), and the Genetics of Kidney Disease in Zuni Indians Study (GKDZI, American Indian). Serum sodium was transformed for the osmotic effect of glucose, and participants with markedly elevated glucose or reduced estimated glomerular filtration rate (eGFR) were excluded. Using a standard variance components method, incorporating covariates of age, glucose, and eGFR, we found heritability to be high in African American and American Indian populations and much more modest in non-Hispanic Caucasian populations. Estimates among females increased after stratification on sex and were suggestive among female participants in FHS (0.18 ± 0.12, P = 0.057) and male participants in JHS (0.24 ± 0.16, P = 0.067) and statistically significant among female participants in JHS (0.44 ± 0.09, P = 1 × 10 ⁻⁷), SHFS (0.59 ± 0.05, P = 9.4 × 10⁻⁴⁶), and GKDZI (0.46 ± 0.15, P = 1.7 × 10⁻⁴), and male participants in HAPI (0.18 ± 0.12, P = 0.03) and SHFS (0.67 ± 0.07, P = 5.4 × 10⁻²⁶). Exclusion of diuretic users increased heritability among females and was significant in all cohorts where data were available. In aggregate, these data strongly support the heritability of systemic water balance and underscore sex and ethnicity-specific effects.
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Affiliation(s)
- Beth Wilmot
- Division of Nephrology & Hypertension, Departments of Medicine, Oregon Health & Science University, Portland, OR, USA
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Runnels LW. TRPM6 and TRPM7: A Mul-TRP-PLIK-cation of channel functions. Curr Pharm Biotechnol 2011; 12:42-53. [PMID: 20932259 DOI: 10.2174/138920111793937880] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2010] [Accepted: 05/07/2010] [Indexed: 12/31/2022]
Abstract
Unique among ion channels, TRPM6 and TRPM7 garnered much interest upon their discovery as the first ion channels to possess their own kinase domain. Soon after their identification, the two proteins were quickly linked to the regulation of magnesium homeostasis. However, study of their physiological functions in mouse and zebrafish have revealed expanding roles for these channel-kinases that include skeletogenesis and melanopore formation, thymopoiesis, cell adhesion, and neural fold closure during early development. In addition, mutations in the TRPM6 gene constitute the underlying genetic defect in hypomagnesemia with secondary hypocalcemia, a rare autosomal-recessive disease characterized by low serum magnesium accompanied by hypocalcemia. Depletion of TRPM7 expression in brain, on the other hand, proved successful in mitigating much of the cellular devastation that accompanies oxygen-glucose deprivation during ischemia. The aim of this review is to summarize the data emerging from molecular genetic, biochemical, electrophysiological, and pharmacological studies of these unique channel-kinases.
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Affiliation(s)
- Loren W Runnels
- Department of Pharmacology, UMDNJ-Robert Wood Johnson Medical School, 675 Hoes Lane, Piscataway, NJ 08854, USA.
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Romani AMP. Cellular magnesium homeostasis. Arch Biochem Biophys 2011; 512:1-23. [PMID: 21640700 PMCID: PMC3133480 DOI: 10.1016/j.abb.2011.05.010] [Citation(s) in RCA: 351] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2011] [Revised: 05/16/2011] [Accepted: 05/17/2011] [Indexed: 12/12/2022]
Abstract
Magnesium, the second most abundant cellular cation after potassium, is essential to regulate numerous cellular functions and enzymes, including ion channels, metabolic cycles, and signaling pathways, as attested by more than 1000 entries in the literature. Despite significant recent progress, however, our understanding of how cells regulate Mg(2+) homeostasis and transport still remains incomplete. For example, the occurrence of major fluxes of Mg(2+) in either direction across the plasma membrane of mammalian cells following metabolic or hormonal stimuli has been extensively documented. Yet, the mechanisms ultimately responsible for magnesium extrusion across the cell membrane have not been cloned. Even less is known about the regulation in cellular organelles. The present review is aimed at providing the reader with a comprehensive and up-to-date understanding of the mechanisms enacted by eukaryotic cells to regulate cellular Mg(2+) homeostasis and how these mechanisms are altered under specific pathological conditions.
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Affiliation(s)
- Andrea M P Romani
- Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106-4970, USA.
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Dwyer L, Rhee PL, Lowe V, Zheng H, Peri L, Ro S, Sanders KM, Koh SD. Basally activated nonselective cation currents regulate the resting membrane potential in human and monkey colonic smooth muscle. Am J Physiol Gastrointest Liver Physiol 2011; 301:G287-96. [PMID: 21566016 PMCID: PMC3154607 DOI: 10.1152/ajpgi.00415.2010] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Resting membrane potential (RMP) plays an important role in determining the basal excitability of gastrointestinal smooth muscle. The RMP in colonic muscles is significantly less negative than the equilibrium potential of K(+), suggesting that it is regulated not only by K(+) conductances but by inward conductances such as Na(+) and/or Ca(2+). We investigated the contribution of nonselective cation channels (NSCC) to the RMP in human and monkey colonic smooth muscle cells (SMC) using voltage- and current-clamp techniques. Qualitative reverse transcriptase-polymerase chain reaction was performed to examine potential molecular candidates for these channels among the transient receptor potential (TRP) channel superfamily. Spontaneous transient inward currents and holding currents were recorded in human and monkey SMC. Replacement of extracellular Na(+) with equimolar tetraethylammonium or Ca(2+) with Mn(2+) inhibited basally activated nonselective cation currents. Trivalent cations inhibited these channels. Under current clamp, replacement of extracellular Na(+) with N-methyl-D-glucamine or addition of trivalent cations caused hyperpolarization. Three unitary conductances of NSCC were observed in human and monkey colonic SMC. Molecular candidates for basally active NSCC were TRPC1, C3, C4, C7, M2, M4, M6, M7, V1, and V2 in human and monkey SMC. Comparison of the biophysical properties of these TRP channels with basally active NSCC (bI(NSCC)) suggests that TRPM4 and specific TRPC heteromultimer combinations may underlie the three single-channel conductances of bI(NSCC). In conclusion, these findings suggest that basally activated NSCC contribute to the RMP in human and monkey colonic SMC and therefore may play an important role in determining basal excitability of colonic smooth muscle.
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Affiliation(s)
- Laura Dwyer
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, 89557, USA.
| | - Poong-Lyul Rhee
- 2Department of Gastroenterology, Samsung Medical Center, Seoul, Korea
| | - Vanessa Lowe
- 1Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, Nevada;
| | - Haifeng Zheng
- 1Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, Nevada;
| | - Lauren Peri
- 1Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, Nevada;
| | - Seungil Ro
- 1Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, Nevada;
| | - Kenton M. Sanders
- 1Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, Nevada;
| | - Sang Don Koh
- 1Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, Nevada;
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Yogi A, Callera GE, Antunes TT, Tostes RC, Touyz RM. Transient receptor potential melastatin 7 (TRPM7) cation channels, magnesium and the vascular system in hypertension. Circ J 2010; 75:237-45. [PMID: 21150127 DOI: 10.1253/circj.cj-10-1021] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Decreased Mg(2+) concentration has been implicated in altered vascular reactivity, endothelial dysfunction and structural remodeling, processes important in vascular changes and target organ damage associated with hypertension. Unlike our knowledge of other major cations, mechanisms regulating cellular Mg(2+) handling are poorly understood. Until recently little was known about protein transporters controlling transmembrane Mg(2+) influx. However, new research has uncovered a number of genes and proteins identified as transmembrane Mg(2+) transporters, particularly transient receptor potential melastatin (TRPM) cation channels, TRPM6 and TRPM7. Whereas TRPM6 is found primarily in epithelial cells, TRPM7 is ubiquitously expressed. Vascular TRPM7 has been implicated as a signaling kinase involved in vascular smooth muscle cell growth, apoptosis, adhesion, contraction, cytoskeletal organization and migration, and is modulated by vasoactive agents, pressure, stretch and osmotic changes. Emerging evidence suggests that vascular TRPM7 function might be altered in hypertension. The present review discusses the importance of Mg(2+) in vascular biology in hypertension and focuses on transport systems, mainly TRPM7, that might play a role in the control of vascular Mg(2+) homeostasis. Elucidation of the relationship between the complex systems responsible for regulation of Mg(2+) homeostasis, the role of TRPM7 in vascular signaling, and the cardiovascular impact will be important for understanding the clinical implications of hypomagnesemia in cardiovascular disease.
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Affiliation(s)
- Alvaro Yogi
- Kidney Research Center, Ottawa Hospital Research Institute, University of Ottawa, Ottawa, Canada
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Cao G, Lee KP, van der Wijst J, de Graaf M, van der Kemp A, Bindels RJM, Hoenderop JGJ. Methionine sulfoxide reductase B1 (MsrB1) recovers TRPM6 channel activity during oxidative stress. J Biol Chem 2010; 285:26081-7. [PMID: 20584906 DOI: 10.1074/jbc.m110.103655] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Mg(2+) is an essential ion for many cellular processes, including protein synthesis, nucleic acid stability, and numerous enzymatic reactions. Mg(2+) homeostasis in mammals depends on the equilibrium between intestinal absorption, renal excretion, and exchange with bone. The transient receptor potential melastatin type 6 (TRPM6) is an epithelial Mg(2+) channel, which is abundantly expressed in the luminal membrane of the renal and intestinal cells. It functions as the gatekeeper of transepithelial Mg(2+) transport. Remarkably, TRPM6 combines a Mg(2+)-permeable channel with an alpha-kinase domain. Here, by the Ras recruitment system, we identified methionine sulfoxide reductase B1 (MsrB1) as an interacting protein of the TRPM6 alpha-kinase domain. Importantly, MsrB1 and TRPM6 are both present in the renal Mg(2+)-transporting distal convoluted tubules. MsrB1 has no effect on TRPM6 channel activity in the normoxic conditions. However, hydrogen peroxide (H(2)O(2)) decreased TRPM6 channel activity. Co-expression of MsrB1 with TRPM6 attenuated the inhibitory effect of H(2)O(2) (TRPM6, 67 +/- 5% of control; TRPM6 + MsrB1, 81 +/- 5% of control). Cell surface biotinylation assays showed that H(2)O(2) treatment does not affect the expression of TRPM6 at the plasma membrane. Next, mutation of Met(1755) to Ala in TRPM6 reduced the inhibitory effect of H(2)O(2) on TRPM6 channel activity (TRPM6 M1755A: 84 +/- 10% of control), thereby mimicking the action of MsrB1. Thus, these data suggest that MsrB1 recovers TRPM6 channel activity by reducing the oxidation of Met(1755) and could, thereby, function as a modulator of TRPM6 during oxidative stress.
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Affiliation(s)
- Gang Cao
- Department of Physiology, Radboud University Nijmegen Medical Centre, HB Nijmegen, The Netherlands
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Abstract
Many ion channels and transporters are involved in the filtration, secretion, and resorption of electrolytes by the kidney. In recent years, the superfamily of transient receptor potential (TRP) ion channels have received deserved attention because mutated TRP channels are linked to human kidney diseases. This review focuses on two TRP members--TRPC6 and TRPM6--and their functions in the kidney. Gain-of-function mutations in TRPC6 are the cause for progressive kidney failure with urinary protein loss such as FSGS. Thus, TRPC6 is an essential signaling component in a functional slit diaphragm formed by podocytes around the glomerular capillaries. Loss-of-function mutations in TRPM6 are a molecular cause of hypomagnesemia with secondary hypocalcemia, suggesting that TRPM6 is critically involved in transcellular Mg2+ transport in the kidney. Here, we highlight how recent studies analyzing function and expression of these channels in the kidney improve our mechanistic understanding of TRP channel function in general and pave the way to new, promising therapeutic strategies to target kidney diseases such as FSGS and hypomagnesemia with secondary hypocalcemia.
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Affiliation(s)
- Alexander Dietrich
- Institute of Pharmacology and Toxicology, School of Medicine, University of Marburg, Marburg, Germany
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Middelbeek J, Clark K, Venselaar H, Huynen MA, van Leeuwen FN. The alpha-kinase family: an exceptional branch on the protein kinase tree. Cell Mol Life Sci 2010; 67:875-90. [PMID: 20012461 PMCID: PMC2827801 DOI: 10.1007/s00018-009-0215-z] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2009] [Revised: 10/27/2009] [Accepted: 11/10/2009] [Indexed: 01/19/2023]
Abstract
The alpha-kinase family represents a class of atypical protein kinases that display little sequence similarity to conventional protein kinases. Early studies on myosin heavy chain kinases in Dictyostelium discoideum revealed their unusual propensity to phosphorylate serine and threonine residues in the context of an alpha-helix. Although recent studies show that some members of this family can also phosphorylate residues in non-helical regions, the name alpha-kinase has remained. During evolution, the alpha-kinase domains combined with many different functional subdomains such as von Willebrand factor-like motifs (vWKa) and even cation channels (TRPM6 and TRPM7). As a result, these kinases are implicated in a large variety of cellular processes such as protein translation, Mg(2+) homeostasis, intracellular transport, cell migration, adhesion, and proliferation. Here, we review the current state of knowledge on different members of this kinase family and discuss the potential use of alpha-kinases as drug targets in diseases such as cancer.
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Affiliation(s)
- Jeroen Middelbeek
- Laboratory of Pediatric Oncology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, PO Box 9101, 6500 HB Nijmegen, The Netherlands
| | - Kristopher Clark
- MRC Protein Phosphorylation Unit, Sir James Black Centre, College of Life Sciences, University of Dundee, Dundee, DD1 5EH Scotland UK
| | - Hanka Venselaar
- Centre for Molecular and Biomolecular Informatics, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, PO Box 9101, 6500 HB Nijmegen, The Netherlands
| | - Martijn A. Huynen
- Centre for Molecular and Biomolecular Informatics, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, PO Box 9101, 6500 HB Nijmegen, The Netherlands
| | - Frank N. van Leeuwen
- Laboratory of Pediatric Oncology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, PO Box 9101, 6500 HB Nijmegen, The Netherlands
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Walder RY, Yang B, Stokes JB, Kirby PA, Cao X, Shi P, Searby CC, Husted RF, Sheffield VC. Mice defective in Trpm6 show embryonic mortality and neural tube defects. Hum Mol Genet 2009; 18:4367-75. [PMID: 19692351 DOI: 10.1093/hmg/ddp392] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The syndrome of hypomagnesemia with secondary hypocalcemia is caused by defective TRPM6. This protein is an ion channel that also contains a kinase in its C-terminus. It is usually diagnosed in childhood and, without treatment with supplemental Mg, affected children suffer from mental retardation, seizures and retarded development. We developed a mouse lacking Trpm6 in order to understand in greater detail the function of this protein. In contrast to our expectations, Trpm6(-/-) mice almost never survived to weaning. Many mice died by embryonic day 12.5. Most that survived to term had neural tube defects consisting of both exencephaly and spina bifida occulta, an unusual combination. Feeding dams a high Mg diet marginally improved offspring survival to weaning. The few Trpm6(-/-) mice that survived were fertile but matings between Trpm6(-/-) mice produced no viable pregnancies. Trpm6(+/-) mice had normal electrolytes except for modestly low plasma [Mg]. In addition, some Trpm6(+/-) mice died prematurely. Absence of Trpm6 produces an apparently different phenotype in mice than in humans. The presence of neural tube defects identifies a previously unsuspected role of Trpm6 in effecting neural tube closure. This genetic defect produces one of very few mouse models of spina bifida occulta. These results point to a critical role of Trpm6 in development and suggest an important role in neural tube closure.
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Affiliation(s)
- Roxanne Y Walder
- Department of Pediatrics, University of Iowa, Iowa City, IA 52242, USA
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