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Pike JW, Lee SM, Meyer MB. Molecular insights into mineralotropic hormone inter-regulation. Front Endocrinol (Lausanne) 2023; 14:1213361. [PMID: 37441497 PMCID: PMC10334211 DOI: 10.3389/fendo.2023.1213361] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Accepted: 06/13/2023] [Indexed: 07/15/2023] Open
Abstract
The regulation of mineral homeostasis involves the three mineralotropic hormones PTH, FGF23 and 1,25-dihydroxyvitamin D3 (1,25(OH)2D3). Early research efforts focused on PTH and 1,25(OH)2D3 and more recently on FGF23 have revealed that each of these hormones regulates the expression of the other two. Despite early suggestions of transcriptional processes, it has been only recently that research effort have begun to delineate the genomic mechanisms underpinning this regulation for 1,25(OH)2D3 and FGF23; the regulation of PTH by 1,25(OH)2D3, however, remains obscure. We review here our molecular understanding of how PTH induces Cyp27b1 expression, the gene encoding the enzyme responsible for the synthesis of 1,25(OH)2D3. FGF23 and 1,25(OH)2D3, on the other hand, function by suppressing production of 1,25(OH)2D3. PTH stimulates the PKA-induced recruitment of CREB and its coactivator CBP at CREB occupied sites within the kidney-specific regulatory regions of Cyp27b1. PKA activation also promotes the nuclear translocation of SIK bound coactivators such as CRTC2, where it similarly interacts with CREB occupied Cyp27b1 sites. The negative actions of both FGF23 and 1,25(OH)2D3 appear to suppress Cyp27b1 expression by opposing the recruitment of CREB coactivators at this gene. Reciprocal gene actions are seen at Cyp24a1, the gene encoding the enzyme that degrades 1,25(OH)2D3, thereby contributing to the overall regulation of blood levels of 1,25(OH)2D3. Relative to PTH regulation, we summarize what is known of how 1,25(OH)2D3 regulates PTH suppression. These studies suggest that it is not 1,25(OH)2D3 that controls PTH levels in healthy subjects, but rather calcium itself. Finally, we describe current progress using an in vivo approach that furthers our understanding of the regulation of Fgf23 expression by PTH and 1,25(OH)2D3 and provide the first evidence that P may act to induce Fgf23 expression via a complex transcriptional mechanism in bone. It is clear, however, that additional advances will need to be made to further our understanding of the inter-regulation of each of these hormonal genes.
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Affiliation(s)
- J. Wesley Pike
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI, United States
| | - Seong Min Lee
- Department of Nutritional Sciences, University of Wisconsin-Madison, Madison, WI, United States
| | - Mark B. Meyer
- Department of Nutritional Sciences, University of Wisconsin-Madison, Madison, WI, United States
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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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Magnesium Status and Calcium/Magnesium Ratios in a Series of Cystic Fibrosis Patients. Nutrients 2022; 14:nu14091793. [PMID: 35565764 PMCID: PMC9104329 DOI: 10.3390/nu14091793] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Revised: 04/21/2022] [Accepted: 04/22/2022] [Indexed: 02/04/2023] Open
Abstract
Magnesium (Mg) is an essential micronutrient that participates in various enzymatic reactions that regulate vital biological functions. The main aim was to assess the Mg status and its association with nutritional indicators in seventeen cystic fibrosis (CF) patients. The serum Mg and calcium (Ca) levels were determined using standardized methods and the dietary Mg intake by prospective 72 h dietary surveys. The mean serum Ca (2.45 mmol/L) and Mg (0.82 mmol/L) had normal levels, and the mean dietary intake of the Ca (127% DRI: Dietary Reference Intake) and Mg (125% DRI) were high. No patients had an abnormal serum Ca. A total of 47% of the subjects had hypomagnesemia and 12% insufficient Mg consumption. One patient had a serum Mg deficiency and inadequate Mg intake. A total of 47 and 82% of our series had a high serum Ca/Mg ratio of >4.70 (mean 4.89) and a low Ca/Mg intake ratio of <1.70 (mean 1.10), respectively. The likelihood of a high Ca/Mg ratio was 49 times higher in patients with a serum Mg deficiency than in normal serum Mg patients. Both Ca/Mg ratios were associated with the risk of developing cardiovascular disease (CVD), type 2 diabetes (T2D), metabolic syndrome (MetS), and even several cancers. Therefore, 53% of the CF patients were at high risk of a Mg deficiency and developing other chronic diseases.
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Ovejero D, Hartley IR, de Castro Diaz LF, Theng E, Li X, Gafni RI, Collins MT. PTH and FGF23 Exert Interdependent Effects on Renal Phosphate Handling: Evidence From Patients With Hypoparathyroidism and Hyperphosphatemic Familial Tumoral Calcinosis Treated With Synthetic Human PTH 1-34. J Bone Miner Res 2022; 37:179-184. [PMID: 34464000 DOI: 10.1002/jbmr.4429] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Revised: 08/12/2021] [Accepted: 08/16/2021] [Indexed: 12/27/2022]
Abstract
Parathyroid hormone (PTH) and fibroblast growth factor 23 (FGF23) both influence blood phosphate levels by regulating urinary phosphate reabsorption. Clinical data suggest that adequate renal phosphate handling requires the presence of both FGF23 and PTH, but robust evidence is lacking. To investigate whether the phosphaturic effects of PTH and FGF23 are interdependent, 11 patients with hypoparathyroidism, which features high blood phosphate in spite of concomitant FGF23 elevation, and 1 patient with hyperphosphatemic familial tumoral calcinosis (HFTC), characterized by deficient intact FGF23 action and resulting hyperphosphatemia, were treated with synthetic human PTH 1-34 (hPTH 1-34). Biochemical parameters, including blood phosphate, calcium, intact FGF23 (iFGF23), nephrogenic cAMP, 1,25(OH)2 vitamin D (1,25D), and tubular reabsorption of phosphate (TRP), were measured at baseline and after hPTH 1-34 treatment. In patients with hypoparathyroidism, administration of hPTH 1-34 increased nephrogenic cAMP, which resulted in serum phosphate normalization followed by a significant decrease in iFGF23. TRP initially decreased and returned to baseline. In the patient with HFTC, hPTH 1-34 administration also increased nephrogenic cAMP, but this did not produce changes in phosphate or TRP. No changes in calcium were observed in any of the studied patients, although prolonged hPTH 1-34 treatment did induce supraphysiologic 1,25D levels in the patient with HFTC. Our results indicate that PTH and FGF23 effects on phosphate regulation are interdependent and both are required to adequately regulate renal phosphate handling. Published 2021. This article is a U.S. Government work and is in the public domain in the USA.
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Affiliation(s)
- Diana Ovejero
- Skeletal Disorders and Mineral Homeostasis Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, USA.,Musculoskeletal Research Unit, Hospital del Mar Medical Research Institute, Centro de Investigación Biomédica en Red de Fragilidad y Envejecimiento Saludable (CIBERFES), Barcelona, Spain
| | - Iris R Hartley
- Skeletal Disorders and Mineral Homeostasis Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, USA
| | - Luis Fernandez de Castro Diaz
- Skeletal Disorders and Mineral Homeostasis Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, USA
| | - Elizabeth Theng
- Skeletal Disorders and Mineral Homeostasis Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, USA
| | - Xiaobai Li
- Biostatistics and Clinical Epidemiology Services (XL), National Institutes of Health, Bethesda, MD, USA
| | - Rachel I Gafni
- Skeletal Disorders and Mineral Homeostasis Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, USA
| | - Michael T Collins
- Skeletal Disorders and Mineral Homeostasis Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, USA
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5
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Chanpaisaeng K, Teerapornpuntakit J, Wongdee K, Charoenphandhu N. Emerging roles of calcium-sensing receptor in the local regulation of intestinal transport of ions and calcium. Am J Physiol Cell Physiol 2020; 320:C270-C278. [PMID: 33356945 DOI: 10.1152/ajpcell.00485.2020] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Whether the intestinal mucosal cells are capable of sensing calcium concentration in the lumen and pericellular interstitium remains enigmatic for decades. Most calcium-regulating organs, such as parathyroid gland, kidney, and bone, are capable of using calcium-sensing receptor (CaSR) to detect plasma calcium and trigger appropriate feedback responses to maintain calcium homeostasis. Although both CaSR transcripts and proteins are abundantly expressed in the crypt and villous enterocytes of the small intestine as well as the surface epithelial cells of the large intestine, the studies of CaSR functions have been limited to amino acid sensing and regulation of epithelial fluid secretion. Interestingly, several lines of recent evidence have indicated that the enterocytes use CaSR to monitor luminal and extracellular calcium levels, thereby reducing the activity of transient receptor potential channel, subfamily V, member 6, and inducing paracrine and endocrine feedback responses to restrict calcium absorption. Recent investigations in zebra fish and rodents have also suggested the role of fibroblast growth factor (FGF)-23 as an endocrine and/or paracrine factor participating in the negative control of intestinal calcium transport. In this review article, besides the CaSR-modulated ion transport, we elaborate the possible roles of CaSR and FGF-23 as well as their crosstalk as parts of a negative feedback loop for counterbalancing the seemingly unopposed calciotropic effect of 1,25-dihydroxyvitamin D3 on the intestinal calcium absorption.
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Affiliation(s)
- Krittikan Chanpaisaeng
- Center of Calcium and Bone Research (COCAB), Faculty of Science, Mahidol University, Bangkok, Thailand.,Functional Ingredients and Food Innovation Research Group, National Center for Genetic Engineering and Biotechnology (BIOTEC), Pathum Thani, Thailand
| | - Jarinthorn Teerapornpuntakit
- Center of Calcium and Bone Research (COCAB), Faculty of Science, Mahidol University, Bangkok, Thailand.,Department of Physiology, Faculty of Medical Science, Naresuan University, Phitsanulok, Thailand
| | - Kannikar Wongdee
- Center of Calcium and Bone Research (COCAB), Faculty of Science, Mahidol University, Bangkok, Thailand.,Faculty of Allied Health Sciences, Burapha University, Chonburi, Thailand
| | - Narattaphol Charoenphandhu
- Center of Calcium and Bone Research (COCAB), Faculty of Science, Mahidol University, Bangkok, Thailand.,Department of Physiology, Faculty of Science, Mahidol University, Bangkok, Thailand.,Institute of Molecular Biosciences, Mahidol University, Nakhon Pathom, Thailand.,The Academy of Science, The Royal Society of Thailand, Bangkok, Thailand
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6
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Rodelo-Haad C, Pendón-Ruiz de Mier MV, Díaz-Tocados JM, Martin-Malo A, Santamaria R, Muñoz-Castañeda JR, Rodríguez M. The Role of Disturbed Mg Homeostasis in Chronic Kidney Disease Comorbidities. Front Cell Dev Biol 2020; 8:543099. [PMID: 33282857 PMCID: PMC7688914 DOI: 10.3389/fcell.2020.543099] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2020] [Accepted: 10/09/2020] [Indexed: 12/19/2022] Open
Abstract
Some of the critical mechanisms that mediate chronic kidney disease (CKD) progression are associated with vascular calcifications, disbalance of mineral metabolism, increased oxidative and metabolic stress, inflammation, coagulation abnormalities, endothelial dysfunction, or accumulation of uremic toxins. Also, it is widely accepted that pathologies with a strong influence in CKD progression are diabetes, hypertension, and cardiovascular disease (CVD). A disbalance in magnesium (Mg) homeostasis, more specifically hypomagnesemia, is associated with the development and progression of the comorbidities mentioned above, and some mechanisms might explain why low serum Mg is associated with negative clinical outcomes such as major adverse cardiovascular and renal events. Furthermore, it is likely that hypomagnesemia causes the release of inflammatory cytokines and C-reactive protein and promotes insulin resistance. Animal models have shown that Mg supplementation reverses vascular calcifications; thus, clinicians have focused on the potential benefits that Mg supplementation may have in humans. Recent evidence suggests that Mg reduces coronary artery calcifications and facilitates peripheral vasodilation. Mg may reduce vascular calcification by direct inhibition of the Wnt/β-catenin signaling pathway. Furthermore, Mg deficiency worsens kidney injury induced by an increased tubular load of phosphate. One important consequence of excessive tubular load of phosphate is the reduction of renal tubule expression of α-Klotho in moderate CKD. Low Mg levels worsen the reduction of Klotho induced by the tubular load of phosphate. Evidence to support clinical translation is yet insufficient, and more clinical studies are required to claim enough evidence for decision-making in daily practice. Meanwhile, it seems reasonable to prevent and treat Mg deficiency. This review aims to summarize the current understanding of Mg homeostasis, the potential mechanisms that may mediate the effect of Mg deficiency on CKD progression, CVD, and mortality.
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Affiliation(s)
- Cristian Rodelo-Haad
- Maimonides Biomedical Research Institute of Cordoba (IMIBIC), Córdoba, Spain.,University of Córdoba, Córdoba, Spain.,Nephrology Service, Reina Sofia University Hospital, Córdoba, Spain.,Spanish Renal Research Network (REDinREN), Institute of Health Carlos III, Madrid, Spain
| | - M Victoria Pendón-Ruiz de Mier
- Maimonides Biomedical Research Institute of Cordoba (IMIBIC), Córdoba, Spain.,University of Córdoba, Córdoba, Spain.,Nephrology Service, Reina Sofia University Hospital, Córdoba, Spain.,Spanish Renal Research Network (REDinREN), Institute of Health Carlos III, Madrid, Spain
| | - Juan Miguel Díaz-Tocados
- Maimonides Biomedical Research Institute of Cordoba (IMIBIC), Córdoba, Spain.,University of Córdoba, Córdoba, Spain
| | - Alejandro Martin-Malo
- Maimonides Biomedical Research Institute of Cordoba (IMIBIC), Córdoba, Spain.,University of Córdoba, Córdoba, Spain.,Nephrology Service, Reina Sofia University Hospital, Córdoba, Spain.,Spanish Renal Research Network (REDinREN), Institute of Health Carlos III, Madrid, Spain
| | - Rafael Santamaria
- Maimonides Biomedical Research Institute of Cordoba (IMIBIC), Córdoba, Spain.,University of Córdoba, Córdoba, Spain.,Nephrology Service, Reina Sofia University Hospital, Córdoba, Spain.,Spanish Renal Research Network (REDinREN), Institute of Health Carlos III, Madrid, Spain
| | - Juan Rafael Muñoz-Castañeda
- Maimonides Biomedical Research Institute of Cordoba (IMIBIC), Córdoba, Spain.,University of Córdoba, Córdoba, Spain.,Nephrology Service, Reina Sofia University Hospital, Córdoba, Spain.,Spanish Renal Research Network (REDinREN), Institute of Health Carlos III, Madrid, Spain
| | - Mariano Rodríguez
- Maimonides Biomedical Research Institute of Cordoba (IMIBIC), Córdoba, Spain.,University of Córdoba, Córdoba, Spain.,Nephrology Service, Reina Sofia University Hospital, Córdoba, Spain.,Spanish Renal Research Network (REDinREN), Institute of Health Carlos III, Madrid, Spain
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7
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Porter C, Sousse LE, Irick R, Schryver E, Klein GL. Interactions of Phosphate Metabolism With Serious Injury, Including Burns. JBMR Plus 2017; 1:59-65. [PMID: 30283881 PMCID: PMC6124193 DOI: 10.1002/jbm4.10011] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Revised: 06/20/2017] [Accepted: 06/21/2017] [Indexed: 11/10/2022] Open
Abstract
Approximately 85% of the body's phosphate pool resides within the skeleton. The remaining 15% is stored as high-energy phosphates or in its free form, where it acts as a substrate for adenosine triphosphate (ATP) production. Accordingly, phosphate plays a crucial role in energy metabolism. Trauma and critical illness result in a hypermetabolic state in which energy expenditure increases. The impact of trauma and critical illness on the body's phosphate stores and phosphate-dependent metabolic reactions is poorly understood. We had previously observed that after severe burn trauma, increased energy expenditure is temporally related to a marked reduction in serum concentrations of both parathyroid hormone and fibroblast growth factor 23, both of which have phosphaturic effects. The aim of this article is to describe as far as is known the similarities and differences in phosphate metabolism in different types of injury and to infer what these differences tell us about possible signaling pathways that may link increased phosphate utilization and phosphate retention. © 2017 The Authors. JBMR Plus is published by Wiley Periodicals, Inc. on behalf of the American Society for Bone and Mineral Research.
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Affiliation(s)
- Craig Porter
- Department of SurgeryUniversity of Texas Medical Branch at GalvestonGalvestonTXUSA
- Shriners Burns HospitalUniversity of Texas Medical Branch at GalvestonGalvestonTXUSA
| | - Linda E Sousse
- Department of SurgeryUniversity of Texas Medical Branch at GalvestonGalvestonTXUSA
- Shriners Burns HospitalUniversity of Texas Medical Branch at GalvestonGalvestonTXUSA
| | - Ryan Irick
- Department of SurgeryUniversity of Texas Medical Branch at GalvestonGalvestonTXUSA
| | - Eric Schryver
- Department of SurgeryUniversity of Texas Medical Branch at GalvestonGalvestonTXUSA
| | - Gordon L Klein
- Shriners Burns HospitalUniversity of Texas Medical Branch at GalvestonGalvestonTXUSA
- Department of Orthopaedic Surgery and RehabilitationUniversity of Texas Medical Branch at GalvestonGalvestonTXUSA
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8
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Abstract
Hypoparathyroidism is a disease characterized by inadequately low circulating concentrations of parathyroid hormone (PTH) resulting in low calcium levels and increased phosphate levels in the blood. Symptoms of the disease result from increased neuromuscular irritability caused by hypocalcaemia and include tingling, muscle cramps and seizures. The most common cause of the disease is inadvertent removal of, or injury to, the parathyroid glands during neck surgery, followed by genetic, idiopathic and autoimmune aetiologies. Conventional treatment includes activated vitamin D and/or calcium supplements, but this treatment does not fully replace the functions of PTH and can lead to short-term problems (such as hypocalcaemia, hypercalcaemia and increased urinary calcium excretion) and long-term complications (which include nephrocalcinosis, kidney stones and brain calcifications). PTH replacement has emerged as a new treatment option. Clinical trials using human PTH(1-34) and PTH(1-84) showed that this treatment was safe and effective in studies lasting up to 6 years. Recombinant human PTH(1-84) has been approved in the United States and Europe for the management of hypoparathyroidism; however, its effect on long-term complications is still being evaluated. Clinical practice guidelines, which describe the consensus of experts in the field, have been published and recognize the need for more research to optimize care. In this Primer, we summarize current knowledge of the prevalence, pathophysiology, clinical presentation and management of hypoparathyroidism.
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Zhang C, Zhang T, Zou J, Miller CL, Gorkhali R, Yang JY, Schilmiller A, Wang S, Huang K, Brown EM, Moremen KW, Hu J, Yang JJ. Structural basis for regulation of human calcium-sensing receptor by magnesium ions and an unexpected tryptophan derivative co-agonist. SCIENCE ADVANCES 2016; 2:e1600241. [PMID: 27386547 PMCID: PMC4928972 DOI: 10.1126/sciadv.1600241] [Citation(s) in RCA: 97] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Accepted: 04/29/2016] [Indexed: 06/06/2023]
Abstract
Ca(2+)-sensing receptors (CaSRs) modulate calcium and magnesium homeostasis and many (patho)physiological processes by responding to extracellular stimuli, including divalent cations and amino acids. We report the first crystal structure of the extracellular domain (ECD) of human CaSR bound with Mg(2+) and a tryptophan derivative ligand at 2.1 Å. The structure reveals key determinants for cooperative activation by metal ions and aromatic amino acids. The unexpected tryptophan derivative was bound in the hinge region between two globular ECD subdomains, and represents a novel high-affinity co-agonist of CaSR. The dissection of structure-function relations by mutagenesis, biochemical, and functional studies provides insights into the molecular basis of human diseases arising from CaSR mutations. The data also provide a novel paradigm for understanding the mechanism of CaSR-mediated signaling that is likely shared by the other family C GPCR [G protein (heterotrimeric guanine nucleotide-binding protein)-coupled receptor] members and can facilitate the development of novel CaSR-based therapeutics.
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Affiliation(s)
- Chen Zhang
- Department of Chemistry, Center for Diagnostics and Therapeutics, Georgia State University, 50 Decatur Street, Atlanta, GA 30303, USA
| | - Tuo Zhang
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, USA
| | - Juan Zou
- Department of Chemistry, Center for Diagnostics and Therapeutics, Georgia State University, 50 Decatur Street, Atlanta, GA 30303, USA
| | - Cassandra Lynn Miller
- Department of Chemistry, Center for Diagnostics and Therapeutics, Georgia State University, 50 Decatur Street, Atlanta, GA 30303, USA
| | - Rakshya Gorkhali
- Department of Chemistry, Center for Diagnostics and Therapeutics, Georgia State University, 50 Decatur Street, Atlanta, GA 30303, USA
| | - Jeong-Yeh Yang
- Department of Biochemistry and Molecular Biology and the Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Road, Athens, GA 30602, USA
| | - Anthony Schilmiller
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, USA
| | - Shuo Wang
- Department of Biochemistry and Molecular Biology and the Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Road, Athens, GA 30602, USA
| | - Kenneth Huang
- Department of Chemistry, Center for Diagnostics and Therapeutics, Georgia State University, 50 Decatur Street, Atlanta, GA 30303, USA
| | - Edward M. Brown
- Division of Endocrinology, Diabetes and Hypertension, Department of Medicine, Brigham and Women’s Hospital and Harvard Medical School, 221 Longwood Avenue, Boston, MA 02115, USA
| | - Kelley W. Moremen
- Department of Biochemistry and Molecular Biology and the Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Road, Athens, GA 30602, USA
| | - Jian Hu
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, USA
- Department of Chemistry, Michigan State University, East Lansing, MI 48824, USA
| | - Jenny J. Yang
- Department of Chemistry, Center for Diagnostics and Therapeutics, Georgia State University, 50 Decatur Street, Atlanta, GA 30303, USA
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10
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Luthringer BJ, Willumeit-Römer R. Effects of magnesium degradation products on mesenchymal stem cell fate and osteoblastogenesis. Gene 2016; 575:9-20. [DOI: 10.1016/j.gene.2015.08.028] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Revised: 08/10/2015] [Accepted: 08/13/2015] [Indexed: 01/02/2023]
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11
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Abstract
Cardiovascular complications are the leading cause of death in patients with chronic kidney disease (CKD). Abundant experimental evidence suggests a physiological role of magnesium in cardiovascular function, and clinical evidence suggests a role of the cation in cardiovascular disease in the general population. The role of magnesium in CKD-mineral and bone disorder, and in particular its impact on cardiovascular morbidity and mortality in patients with CKD, is however not well understood. Experimental studies have shown that magnesium inhibits vascular calcification, both by direct effects on the vessel wall and by indirect, systemic effects. Moreover, an increasing number of epidemiologic studies in patients with CKD have shown associations of serum magnesium levels with intermediate and hard outcomes, including vascular calcification, cardiovascular events and mortality. Intervention trials in these patients conducted to date have had small sample sizes and have been limited to the study of surrogate parameters, such as arterial stiffness, vascular calcification and atherosclerosis. Randomized controlled trials are clearly needed to determine the effects of magnesium supplementation on hard outcomes in patients with CKD.
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12
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Abstract
The extracellular calcium-sensing receptor, CaSR, is a member of the G protein-coupled receptor superfamily and has a critical role in modulating Ca(2+) homeostasis via its role in the parathyroid glands and kidneys. New evidence suggests that CaSR expression in cartilage and bone also directly regulates skeletal homeostasis. This Review discusses the role of CaSR in chondrocytes, through which CaSR contributes to the development of the cartilaginous growth plate, as well as in osteoblasts and osteoclasts, through which CaSR has effects on skeletal development and bone turnover in young and mature animals. The interaction of skeletal CaSR activation with parathyroid hormone (PTH), which is secreted by the parathyroid gland, can lead to net bone formation in trabecular bone or net bone resorption in cortical bone. Allosteric modulators of CaSR are beneficial in some clinical conditions, with effects that are mediated by the ability of these agents to alter levels of PTH and improve Ca(2+) homeostasis. However, further insights into the action of CaSR in bone cells might lead to CaSR-based drugs that maximize not only the effects of the receptor on the parathyroid glands and kidneys but also on bone.
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Affiliation(s)
- David Goltzman
- Department of Medicine, McGill University, 687 Pine Avenue West, Montreal, QC H3A 1A1, Canada
| | - Geoffrey N Hendy
- Department of Medicine, McGill University, 687 Pine Avenue West, Montreal, QC H3A 1A1, Canada
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13
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Lameris AL, Nevalainen PI, Reijnen D, Simons E, Eygensteyn J, Monnens L, Bindels RJM, Hoenderop JGJ. Segmental transport of Ca²⁺ and Mg²⁺ along the gastrointestinal tract. Am J Physiol Gastrointest Liver Physiol 2015; 308:G206-16. [PMID: 25477372 DOI: 10.1152/ajpgi.00093.2014] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Calcium (Ca(2+)) and magnesium (Mg(2+)) ions are involved in many vital physiological functions. Since dietary intake is the only source of minerals for the body, intestinal absorption is essential for normal homeostatic levels. The aim of this study was to characterize the absorption of Ca(2+) as well as Mg(2+) along the gastrointestinal tract at a molecular and functional level. In both humans and mice the Ca(2+) channel transient receptor potential vanilloid subtype 6 (TRPV6) is expressed in the proximal intestinal segments, whereas Mg(2+) channel transient receptor potential melastatin subtype 6 (TRPM6) is expressed in the distal parts of the intestine. A method was established to measure the rate of Mg(2+) absorption from the intestine in a time-dependent manner by use of (25)Mg(2+). In addition, local absorption of Ca(2+) and Mg(2+) in different segments of the intestine of mice was determined by using surgically implanted intestinal cannulas. By these methods, it was demonstrated that intestinal absorption of Mg(2+) is regulated by dietary needs in a vitamin D-independent manner. Also, it was shown that at low luminal concentrations, favoring transcellular absorption, Ca(2+) transport mainly takes place in the proximal segments of the intestine, whereas Mg(2+) absorption predominantly occurs in the distal part of the gastrointestinal tract. Vitamin D treatment of mice increased serum Mg(2+) levels and 24-h urinary Mg(2+) excretion, but not intestinal absorption of (25)Mg(2+). Segmental cannulation of the intestine and time-dependent absorption studies using (25)Mg(2+) provide new ways to study intestinal Mg(2+) absorption.
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Affiliation(s)
- Anke L Lameris
- Department of Physiology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Pasi I Nevalainen
- School of Medicine, University of Tampere, Tampere, Finland; Department of Internal Medicine, Tampere University Hospital, Tampere, Finland
| | - Daphne Reijnen
- Central Animal Facility, Radboud University, Nijmegen, The Netherlands; and
| | - Ellen Simons
- Department of Physiology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Jelle Eygensteyn
- Department of General Instrumentation, Faculty of Sciences, Radboud University, Nijmegen, The Netherlands
| | - Leo Monnens
- Department of Physiology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - 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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14
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Floege J. Magnesium in CKD: more than a calcification inhibitor? J Nephrol 2014; 28:269-77. [PMID: 25227765 PMCID: PMC4439441 DOI: 10.1007/s40620-014-0140-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2014] [Accepted: 09/02/2014] [Indexed: 01/30/2023]
Abstract
Magnesium fulfils important roles in multiple physiological processes. Accordingly, a tight regulation of magnesium homeostasis is essential. Dysregulated magnesium serum levels, in particular hypomagnesaemia, are common in patients with chronic kidney disease (CKD) and have been associated with poor clinical outcomes. In cell culture studies as well as in clinical situations magnesium levels were associated with vascular calcification, cardiovascular disease and altered bone-mineral metabolism. Magnesium has also been linked to diseases such as metabolic syndrome, diabetes, hypertension, fatigue and depression, all of which are common in CKD. The present review summarizes and discusses the latest clinical data on the impact of magnesium and possible effects of higher levels on the health status of patients with CKD, including an outlook on the use of magnesium-based phosphate-binding agents in this context.
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Affiliation(s)
- Jürgen Floege
- Division of Nephrology and Clinical Immunology, RWTH University of Aachen, Pauwelsstr. 30, 52057, Aachen, Germany,
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15
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Aihara E, Montrose MH. Importance of Ca(2+) in gastric epithelial restitution-new views revealed by real-time in vivo measurements. Curr Opin Pharmacol 2014; 19:76-83. [PMID: 25108560 DOI: 10.1016/j.coph.2014.07.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2014] [Revised: 07/22/2014] [Accepted: 07/22/2014] [Indexed: 12/14/2022]
Abstract
It has been a few decades since Ca(2+) was identified as one of the important factors that can accelerate gastric wound repair as well as contribute to epithelial homeostasis and regulation of gastric secretions. The mechanistic basis has remained largely unexplored in vivo because it was not possible to track in real time either intracellular Ca(2+) mobilization or wound repair in living tissues. Recent advances in technology, such as combining high resolution light microscopy and genetically encoded Ca(2+) reporters in mice, now allow the monitoring of Ca(2+) mobilization during gastric epithelial cell restitution. Ca(2+) is a ubiquitous second messenger that influences numerous cellular processes, including gastric acid/bicarbonate secretion, mucus secretion, and cell migration. We have demonstrated that cytosolic Ca(2+) mobilization within the restituting gastric epithelial cells is a central signal driving small wound repair. However, extracellular Ca(2+) is also mobilized in the juxtamucosal luminal space above a wound, and evidence suggests extracellular Ca(2+) is a third messenger that also promotes gastric epithelial restitution. Interplay between intracellular and extracellular Ca(2+) is necessary for efficient gastric epithelial restitution.
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Affiliation(s)
- Eitaro Aihara
- Department of Molecular and Cellular Physiology, University of Cincinnati, OH 45267, USA
| | - Marshall H Montrose
- Department of Molecular and Cellular Physiology, University of Cincinnati, OH 45267, USA.
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16
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Gandhe MB, Jain K, Gandhe SM. Evaluation of 25(OH) Vitamin D3 with Reference to Magnesium Status and Insulin Resistance in T2DM. J Clin Diagn Res 2013; 7:2438-41. [PMID: 24392366 DOI: 10.7860/jcdr/2013/6578.3568] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2013] [Accepted: 07/03/2013] [Indexed: 01/13/2023]
Abstract
INTRODUCTION Calcium is a recognized second messenger implicated in insulin secretion. Vitamin D (1,25-dihydroxycholecalciferol, Calcitriol) plays a role in calcium metabolism. This explains the indirect role of Vitamin D in insulin secretion and insulin sensitivity. Hence, low Vitamin D levels are implicated in decreased insulin secretion and increased insulin resistance. In this study, we tried to find out the probable association of Vitamin D3, calcium and magnesium with reference to insulin resistance in type 2 diabetes mellitus (T2DM) cases. It is well documented that measurement of circulating 25-Hydroxycholecalciferol {25 (OH)Vitamin D3} is a marker of total Vitamin D status. METHODOLOGY We measured 25(OH) Vitamin D3 levels in thirty T2DM subjects with thirty age and sex matched healthy controls. We estimated Vitamin D status, calcium and magnesium levels in the light of insulin resistance. Insulin resistance was measured by homeostasis model assessment of insulin resistance (HOMA-IR). RESULTS Twenty five (OH) Vitamin-D3 level was significantly low among T2DM cases (12.29+2.32ng/ml) in comparison to healthy controls (19.55+0.50ng/ml) (p<0.01). The levels of calcium and magnesium were also significantly low in T2DM cases as compared to healthy controls (p<0.01). There was significant negative correlation between Vitamin D status and insulin levels, and insulin resistance (p<0.01). IMPLICATION A significant negative correlation between Vitamin D status and insulin levels suggest that the supplementation of Vitamin D has the potential to increase insulin sensitivity and lower the risk of developing type 2 diabetes mellitus.
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Affiliation(s)
- Mahendra Bhauraoji Gandhe
- Assistant Professor, Department of Biochemistry, Mahatma Gandhi Medical College and Research Institute , Pondicherry, India
| | - Keerthi Jain
- Intern, Mahatma Gandhi Medical College and Research Institute , Pondicherry, India
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17
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Silver J, Naveh-Many T. FGF-23 and secondary hyperparathyroidism in chronic kidney disease. Nat Rev Nephrol 2013; 9:641-9. [PMID: 23877588 DOI: 10.1038/nrneph.2013.147] [Citation(s) in RCA: 81] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The metabolic changes that occur in patients with chronic kidney disease (CKD) have a profound influence on mineral and bone metabolism. CKD results in altered levels of serum phosphate, vitamin D, calcium, parathyroid hormone (PTH) and fibroblast growth factor 23 (FGF-23); the increased levels of serum phosphate, PTH and FGF-23 contribute to the increased cardiovascular mortality in affected patients. FGF-23 is produced by osteocytes and osteoblasts and acts physiologically in the kidney to induce phosphaturia and inhibit the synthesis of 1,25-dihydroxyvitamin D3. PTH acts directly on osteocytes to increase FGF-23 expression. In addition, the high levels of PTH associated with CKD contribute to changes in bone remodelling that result in decreased levels of dentin matrix protein 1 and the release of low-molecular-weight fibroblast growth factors from the bone matrix, which stimulate FGF-23 transcription. A prolonged oral phosphorus load increases FGF-23 expression by a mechanism that includes local changes in the ratio of inorganic phosphate to pyrophosphate in bone. Other factors such as dietary vitamin D compounds, calcium, and metabolic acidosis all increase FGF-23 levels. This Review discusses the mechanisms by which secondary hyperparathyroidism associated with CKD stimulates bone cells to overexpress FGF-23 levels.
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Affiliation(s)
- Justin Silver
- Hadassah Hebrew University Medical Center, Minerva Center for Calcium and Bone Metabolism, Nephrology, Ein Karem, Jerusalem 91120, Israel
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