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Goto M, Nishimura G, Sato H, Yamaguchi Y, Morimoto N, Hashimoto H, Takahashi N. Pharmacological profile of upacicalcet, a novel positive allosteric modulator of calcium-sensing receptor, in vitro and in vivo. Eur J Pharmacol 2023; 956:175936. [PMID: 37541363 DOI: 10.1016/j.ejphar.2023.175936] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 07/10/2023] [Accepted: 07/31/2023] [Indexed: 08/06/2023]
Abstract
Upacicalcet (formerly SK-1403/AJT240) is a novel non-peptide calcimimetic agent that acts as a calcium-sensing receptor (CaSR) agonist for the treatment of secondary hyperparathyroidism (SHPT) in chronic kidney disease (CKD). We compared upacicalcet with other calcimimetics (etelcalcetide or cinacalcet) and examined its in vitro and in vivo characteristics in terms of its human CaSR agonistic activity, its efficacy in normal and CKD rats after a single administration, and its effect on gastric emptying in rats. Upacicalcet activated human CaSR depending on the extracellular calcium (Ca2+) concentration without exhibiting an agonistic action when the extracellular Ca2+ level was below the physiological level. On the other hand, etelcalcetide had an agonistic activity even in the absence of physiological levels of extracellular Ca2+. The intravenous administration of upacicalcet to normal and double-nephrectomized rats dose-dependently (0.03-3mg/kg and 0.3-30mg/kg, respectively) decreased the serum intact parathyroid hormone (iPTH) and serum Ca2+ levels; however, the effect of upacicalcet on the reduction in serum Ca2+ disappeared at extracellular Ca2+ levels below the physiologically range, even when administered at a dose higher (100-fold) than the effective dose. Furthermore, upacicalcet did not affect gastric emptying in normal rats when administered up to a dose of 10mg/kg (300-fold higher than the dose affecting serum iPTH levels), while the administration of cinacalcet significantly slowed gastric emptying by approximately 50%. These findings suggest that upacicalcet has potential as an alternative calcimimetic agent with good pharmacological properties and a lower risk of hypocalcemia and gastrointestinal complications.
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Affiliation(s)
- Moritaka Goto
- Pharmaceuticals Research Laboratories, Sanwa Kagaku Kenkyusho Co., Ltd., 363 Shiosaki, Hokusei-cho, Inabe, Mie, 511-0406, Japan.
| | - Go Nishimura
- Pharmaceuticals Research Laboratories, Sanwa Kagaku Kenkyusho Co., Ltd., 363 Shiosaki, Hokusei-cho, Inabe, Mie, 511-0406, Japan
| | - Hirofumi Sato
- Pharmaceuticals Research Laboratories, Sanwa Kagaku Kenkyusho Co., Ltd., 363 Shiosaki, Hokusei-cho, Inabe, Mie, 511-0406, Japan
| | - Yu Yamaguchi
- Pharmaceuticals Research Laboratories, Sanwa Kagaku Kenkyusho Co., Ltd., 363 Shiosaki, Hokusei-cho, Inabe, Mie, 511-0406, Japan
| | - Nobutaka Morimoto
- Pharmaceuticals Research Laboratories, Sanwa Kagaku Kenkyusho Co., Ltd., 363 Shiosaki, Hokusei-cho, Inabe, Mie, 511-0406, Japan
| | - Hiroyuki Hashimoto
- Pharmaceuticals Research Laboratories, Sanwa Kagaku Kenkyusho Co., Ltd., 363 Shiosaki, Hokusei-cho, Inabe, Mie, 511-0406, Japan
| | - Naoki Takahashi
- Pharmaceuticals Research Laboratories, Sanwa Kagaku Kenkyusho Co., Ltd., 363 Shiosaki, Hokusei-cho, Inabe, Mie, 511-0406, Japan
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Akiyama T, Curtis E, Carstens MI, Carstens E. Enhancement of allyl isothiocyanate-evoked responses of mouse trigeminal ganglion cells by the kokumi substance γ-glutamyl-valyl-glycine (γ-EVG) through activation of the calcium-sensing receptor (CaSR). Physiol Behav 2023; 260:114063. [PMID: 36563734 DOI: 10.1016/j.physbeh.2022.114063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 09/30/2022] [Accepted: 12/15/2022] [Indexed: 12/24/2022]
Abstract
Some γ-glutamyl peptides including glutathione (γ-Glu-Cys-Gly) and γ-glutamyl-valyl-glycine (γ-Glu-Val-Gly= γ-EVG) are reported to increase the intensity of basic tastes, such as salty, sweet, and umami, although they have no taste themselves at tested concentrations. The mechanism of action of γ-glutamyl peptides is not clearly understood, but the calcium sensing receptor (CaSR) may be involved. Glutathione and γ-EVG enhance the pungency of some spices, and the present study investigated the effects of γ-EVG on the responses of trigeminal ganglion (TG) cells to thermosensitiveTRP channel agonists. Single-cell RT-PCR revealed that most CaSR-expressing cells co-expressed TRPV1 (sensitive to capsaicin) and TRPA1 (sensitive to allyl isothiocyanate= AITC). Intracellular Ca2+ imaging showed that pretreatment with γ-EVG excited 7% of trigeminal ganglion (TG) cells and increased the amplitude of their responses to AITC, but not to capsaicin or menthol. The enhancing effect of γ-EVG was prevented by a CaSR inhibitor. The results indicate that γ-EVG increases AITC pungency by activating a subset of trigeminal ganglion cells that co-express CaSR and TRPA1.
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Affiliation(s)
- Tasuku Akiyama
- Dept. of Dermatology & Cutaneous Surgery, Univ. of Miami Miller School of Medicine, Miami FL United States of America
| | - Eric Curtis
- Department of Neurobiology, Physiology and Behavior, University of California, Davis, California, United States of America
| | - M Iodi Carstens
- Department of Neurobiology, Physiology and Behavior, University of California, Davis, California, United States of America
| | - E Carstens
- Department of Neurobiology, Physiology and Behavior, University of California, Davis, California, United States of America.
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Kitajima S, Maruyama Y, Sasaki K, Tajima T, Kuroda M. Increases in the pungency of allyl isothiocyanate and piperine by CaSR agonists, glutathione and γ-glutamyl-valyl-glycine. Physiol Behav 2022; 256:113952. [PMID: 36027984 DOI: 10.1016/j.physbeh.2022.113952] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2022] [Revised: 07/25/2022] [Accepted: 08/23/2022] [Indexed: 11/18/2022]
Abstract
γ-Glutamyl peptides, including glutathione (γ-Glu-Cys-Gly, GSH) and γ-glutamyl-valyl-glycine (γ-Glu-Val-Gly), have been shown to increase the intensity of basic tastes, such as salty, sweet, and umami, and flavor, including mouthfulness, but had no taste themselves at the concentrations tested. Although the mechanisms of action of γ-glutamyl peptides currently remain unclear, the involvement of the calcium sensing receptor (CaSR) has been suggested. Since GSH and γ-Glu-Val-Gly increase the pungency of some spices, the present study investigated their effects on the pungency of allyl isothiocyanate (AITC) using a sensory evaluation. GSH and γ-Glu-Val-Gly both significantly increased the pungency of AITC, while anserine, a peptide without CaSR activity, did not. GSH-induced increases in pungency were suppressed by NPS-2143, a CaSR inhibitor. Further, γ-Glu-Val-Gly significantly increased the pungency of piperine. The present results suggest that GSH and γ-Glu-Val-Gly increased the pungency by activating CaSR.
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Affiliation(s)
- Seiji Kitajima
- Institute of Food Research and Technologies, Ajinomoto Co., Inc., 1-1 Suzuki-cho, Kawasaki-ku, Kawasaki, Kanagawa 210-8681, Japan
| | - Yutaka Maruyama
- Institute of Food Research and Technologies, Ajinomoto Co., Inc., 1-1 Suzuki-cho, Kawasaki-ku, Kawasaki, Kanagawa 210-8681, Japan
| | - Keita Sasaki
- Institute of Food Research and Technologies, Ajinomoto Co., Inc., 1-1 Suzuki-cho, Kawasaki-ku, Kawasaki, Kanagawa 210-8681, Japan
| | - Takaho Tajima
- Institute of Food Research and Technologies, Ajinomoto Co., Inc., 1-1 Suzuki-cho, Kawasaki-ku, Kawasaki, Kanagawa 210-8681, Japan
| | - Motonaka Kuroda
- Institute of Food Research and Technologies, Ajinomoto Co., Inc., 1-1 Suzuki-cho, Kawasaki-ku, Kawasaki, Kanagawa 210-8681, Japan.
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Dinh LV, DeBono A, Keller AN, Josephs TM, Gregory KJ, Leach K, Capuano B. Development of AC265347-Inspired Calcium-Sensing Receptor Ago-Positive Allosteric Modulators. ChemMedChem 2021; 16:3451-3462. [PMID: 34216111 DOI: 10.1002/cmdc.202100368] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Indexed: 11/07/2022]
Abstract
The calcium-sensing receptor (CaSR) is a clinical target in the treatment of hyperparathyroidism and related diseases. However, clinical use of approved CaSR-targeting drugs such as cinacalcet is limited due to adverse side effects including hypocalcaemia, nausea and vomiting, and in some instances, a lack of efficacy. The CaSR agonist and positive allosteric modulator (ago-PAM), AC265347, is chemically distinct from clinically-approved CaSR PAMs. AC265347 potently suppressed parathyroid hormone (PTH) release in rats with a lower propensity to cause hypocalcaemia compared to cinacalcet and may therefore offer benefits over current CaSR PAMs. Here we report a structure activity relationship (SAR) study seeking to optimise AC265347 as a drug candidate and disclose the discovery of AC265347-like compounds with diverse pharmacology and improved physicochemical and drug-like properties.
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Affiliation(s)
- Le Vi Dinh
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University), 381 Royal Parade, Monash University, Parkville, VIC 3052, Australia
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University), 381 Royal Parade, Monash University, Parkville, VIC 3052, Australia
| | - Aaron DeBono
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University), 381 Royal Parade, Monash University, Parkville, VIC 3052, Australia
| | - Andrew N Keller
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University), 381 Royal Parade, Monash University, Parkville, VIC 3052, Australia
| | - Tracy M Josephs
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University), 381 Royal Parade, Monash University, Parkville, VIC 3052, Australia
| | - Karen J Gregory
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University), 381 Royal Parade, Monash University, Parkville, VIC 3052, Australia
- Department of Pharmacology, Monash University, 9 Ancora Imparo Way, Clayton, VIC 3800, Australia
| | - Katie Leach
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University), 381 Royal Parade, Monash University, Parkville, VIC 3052, Australia
- Department of Pharmacology, Monash University, 9 Ancora Imparo Way, Clayton, VIC 3800, Australia
| | - Ben Capuano
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University), 381 Royal Parade, Monash University, Parkville, VIC 3052, Australia
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Celli A, Tu CL, Lee E, Bikle DD, Mauro TM. Decreased Calcium-Sensing Receptor Expression Controls Calcium Signaling and Cell-To-Cell Adhesion Defects in Aged Skin. J Invest Dermatol 2021; 141:2577-2586. [PMID: 33862069 PMCID: PMC8526647 DOI: 10.1016/j.jid.2021.03.025] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Revised: 02/18/2021] [Accepted: 03/01/2021] [Indexed: 11/24/2022]
Abstract
The calcium-sensing receptor (CaSR) drives essential calcium ion (Ca2+) and E-cadherin‒mediated processes in the epidermis, including differentiation, cell-to-cell adhesion, and epidermal barrier homeostasis in cells and in young adult mice. We now report that decreased CaSR expression leads to impaired Ca2+ signal propagation in aged mouse (aged >22 months) epidermis and human (aged >79 years, donor age) keratinocytes. Baseline cytosolic Ca2+ concentrations were higher, and capacitive Ca2+ entry was lower in aged than in young keratinocytes. As in Casr-knockout mice (EpidCaSR-/-), decreased CaSR expression led to decreased E-cadherin and phospholipase C-γ expression and to a compensatory upregulation of STIM1. Pretreatment with the CaSR agonist N-(3-[2-chlorophenyl]propyl)-(R)-alpha-methyl-3-methoxybenzylamine normalized Ca2+ propagation and E-cadherin organization after experimental wounding. These results suggest that age-related defects in CaSR expression dysregulate normal keratinocyte and epidermal Ca2+ signaling, leading to impaired E-cadherin expression, organization, and function. These findings show an innovative mechanism whereby Ca2+- and E-cadherin‒dependent functions are impaired in aging epidermis and suggest a new therapeutic approach by restoring CaSR function.
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Affiliation(s)
- Anna Celli
- Department of Dermatology, SFVAHCS Medical Center and University of California San Francisco, San Francisco, California, USA
| | - Chia-Ling Tu
- Endocrine Unit, San Francisco VA Medical Center (SFVAMC), San Francisco, California, USA; Department of Medicine, University of California-San Francisco (UCSF), San Francisco, California, USA
| | - Elise Lee
- Department of Dermatology, SFVAHCS Medical Center and University of California San Francisco, San Francisco, California, USA
| | - Daniel D Bikle
- Departments of Medicine and Dermatology, UCSF Staff Physician, SF Department of Health Affairs Medical Center, San Francisco, California, USA
| | - Theodora M Mauro
- Department of Dermatology, SFVAHCS Medical Center and University of California San Francisco, San Francisco, California, USA.
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Guo S, Yan T, Shi L, Liu A, Zhang T, Xu Y, Jiang W, Yang Q, Yang L, Liu L, Zhao R, Zhang S. Matrine, as a CaSR agonist promotes intestinal GLP-1 secretion and improves insulin resistance in diabetes mellitus. Phytomedicine 2021; 84:153507. [PMID: 33636577 DOI: 10.1016/j.phymed.2021.153507] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 02/02/2021] [Accepted: 02/08/2021] [Indexed: 06/12/2023]
Abstract
BACKGROUND Matrine (Mat), a bitter tastes compounds of derived from leguminosae such as Sophora flavescens and S. subprostrata, commonly used to improve obesity and diabetes. PURPOSE Our study to demonstrate bitter substances can stimulate the Bitter taste receptors (TAS2Rs) or Calcium-sensing receptor (CaSR) to stimulate the secretion of GLP-1 to promote blood glucose regulation. METHODS The diabetic mice and intestinal secretory cell model were established to evaluate the Mat on glucose metabolism, intestinal insulin secretion and GLP-1 secretion related substances. To clarify the mechanism of Mat in regulating GLP-1 secretion by immunofluorescence, calcium labeling, siRNA, and molecular docking. RESULTS The results showed that Mat could significantly improve glucose metabolism and increased insulin and GLP-1 secretion in diabetic mice and increased trisphosphate inositol (IP3) levels by affecting the expression of phospholipase C β2 (PLCβ2) and promote an increase in intracellular Ca2+ levels in STC-1 cells to subsequently stimulate the secretion of GLP-1. Knockdown of the bitter taste receptors mTas2r108, mTas2r137, and mTas2r138 in STC-1 cells by siRNA did could not affect the role of Mat in regulating GLP-1. However, the secretion of GLP-1 by Mat could be significantly inhibited by administration of a CaSR inhibitor or siRNA CaSR. Molecular docking analysis showed that Mat could embed CaSR protein and bind to the original ligand of the egg white at the same amino acid site to play the role of an agonist. CONCLUSION Matrine is a typical bitter alkaloid could be used as an agonist of CaSR to stimulate the secretion of GLP-1 in the intestine, and it may be used as a potential drug for diabetes treatment.
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Affiliation(s)
- Shun Guo
- Department of Pharmacy, The Second Affiliated Hospital of Air Force Medical University, Xi'an, 710038, PR China
| | - Tao Yan
- Department of Pharmacy, The Second Affiliated Hospital of Air Force Medical University, Xi'an, 710038, PR China
| | - Lei Shi
- Department of Pharmacy, The Second Affiliated Hospital of Air Force Medical University, Xi'an, 710038, PR China
| | - An Liu
- Department of Pharmacy, The Second Affiliated Hospital of Air Force Medical University, Xi'an, 710038, PR China
| | - Tian Zhang
- Department of Pharmacy, The Second Affiliated Hospital of Air Force Medical University, Xi'an, 710038, PR China
| | - Yuan Xu
- Department of Pharmacy, The Second Affiliated Hospital of Air Force Medical University, Xi'an, 710038, PR China
| | - Wei Jiang
- Department of Pharmacy, The Second Affiliated Hospital of Air Force Medical University, Xi'an, 710038, PR China
| | - Qi Yang
- Department of Pharmacy, The Second Affiliated Hospital of Air Force Medical University, Xi'an, 710038, PR China
| | - Le Yang
- Department of Pharmacy, The Second Affiliated Hospital of Air Force Medical University, Xi'an, 710038, PR China
| | - Linna Liu
- Department of Pharmacy, The Second Affiliated Hospital of Air Force Medical University, Xi'an, 710038, PR China..
| | - Rong Zhao
- Department of Cardiovascular Surgery, The First Affiliated Hospital of Air Force Medical University, Xi'an 710032, PR China..
| | - Song Zhang
- Department of Pharmacy, The Second Affiliated Hospital of Air Force Medical University, Xi'an, 710038, PR China..
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Leach K, Hannan FM, Josephs TM, Keller AN, Møller TC, Ward DT, Kallay E, Mason RS, Thakker RV, Riccardi D, Conigrave AD, Bräuner-Osborne H. International Union of Basic and Clinical Pharmacology. CVIII. Calcium-Sensing Receptor Nomenclature, Pharmacology, and Function. Pharmacol Rev 2020; 72:558-604. [PMID: 32467152 PMCID: PMC7116503 DOI: 10.1124/pr.119.018531] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The calcium-sensing receptor (CaSR) is a class C G protein-coupled receptor that responds to multiple endogenous agonists and allosteric modulators, including divalent and trivalent cations, L-amino acids, γ-glutamyl peptides, polyamines, polycationic peptides, and protons. The CaSR plays a critical role in extracellular calcium (Ca2+ o) homeostasis, as demonstrated by the many naturally occurring mutations in the CaSR or its signaling partners that cause Ca2+ o homeostasis disorders. However, CaSR tissue expression in mammals is broad and includes tissues unrelated to Ca2+ o homeostasis, in which it, for example, regulates the secretion of digestive hormones, airway constriction, cardiovascular effects, cellular differentiation, and proliferation. Thus, although the CaSR is targeted clinically by the positive allosteric modulators (PAMs) cinacalcet, evocalcet, and etelcalcetide in hyperparathyroidism, it is also a putative therapeutic target in diabetes, asthma, cardiovascular disease, and cancer. The CaSR is somewhat unique in possessing multiple ligand binding sites, including at least five putative sites for the "orthosteric" agonist Ca2+ o, an allosteric site for endogenous L-amino acids, two further allosteric sites for small molecules and the peptide PAM, etelcalcetide, and additional sites for other cations and anions. The CaSR is promiscuous in its G protein-coupling preferences, and signals via Gq/11, Gi/o, potentially G12/13, and even Gs in some cell types. Not surprisingly, the CaSR is subject to biased agonism, in which distinct ligands preferentially stimulate a subset of the CaSR's possible signaling responses, to the exclusion of others. The CaSR thus serves as a model receptor to study natural bias and allostery. SIGNIFICANCE STATEMENT: The calcium-sensing receptor (CaSR) is a complex G protein-coupled receptor that possesses multiple orthosteric and allosteric binding sites, is subject to biased signaling via several different G proteins, and has numerous (patho)physiological roles. Understanding the complexities of CaSR structure, function, and biology will aid future drug discovery efforts seeking to target this receptor for a diversity of diseases. This review summarizes what is known to date regarding key structural, pharmacological, and physiological features of the CaSR.
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Affiliation(s)
- Katie Leach
- Drug Discovery Biology, Monash Institute of Pharmaceutical Science, Monash University, Parkville, Australia (K.L., T.M.J., A.N.K.); Nuffield Department of Women's & Reproductive Health (F.M.H.) and Academic Endocrine Unit, Radcliffe Department of Clinical Medicine (F.M.H., R.V.T.), University of Oxford, Oxford, United Kingdom; Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark (T.C.M., H.B.-O.); Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom (D.T.W.); Department of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria (E.K.); Physiology, School of Medical Sciences and Bosch Institute (R.S.M.) and School of Life & Environmental Sciences, Charles Perkins Centre (A.D.C.), University of Sydney, Sydney, Australia; and School of Biosciences, Cardiff University, Cardiff, United Kingdom (D.R.)
| | - Fadil M Hannan
- Drug Discovery Biology, Monash Institute of Pharmaceutical Science, Monash University, Parkville, Australia (K.L., T.M.J., A.N.K.); Nuffield Department of Women's & Reproductive Health (F.M.H.) and Academic Endocrine Unit, Radcliffe Department of Clinical Medicine (F.M.H., R.V.T.), University of Oxford, Oxford, United Kingdom; Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark (T.C.M., H.B.-O.); Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom (D.T.W.); Department of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria (E.K.); Physiology, School of Medical Sciences and Bosch Institute (R.S.M.) and School of Life & Environmental Sciences, Charles Perkins Centre (A.D.C.), University of Sydney, Sydney, Australia; and School of Biosciences, Cardiff University, Cardiff, United Kingdom (D.R.)
| | - Tracy M Josephs
- Drug Discovery Biology, Monash Institute of Pharmaceutical Science, Monash University, Parkville, Australia (K.L., T.M.J., A.N.K.); Nuffield Department of Women's & Reproductive Health (F.M.H.) and Academic Endocrine Unit, Radcliffe Department of Clinical Medicine (F.M.H., R.V.T.), University of Oxford, Oxford, United Kingdom; Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark (T.C.M., H.B.-O.); Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom (D.T.W.); Department of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria (E.K.); Physiology, School of Medical Sciences and Bosch Institute (R.S.M.) and School of Life & Environmental Sciences, Charles Perkins Centre (A.D.C.), University of Sydney, Sydney, Australia; and School of Biosciences, Cardiff University, Cardiff, United Kingdom (D.R.)
| | - Andrew N Keller
- Drug Discovery Biology, Monash Institute of Pharmaceutical Science, Monash University, Parkville, Australia (K.L., T.M.J., A.N.K.); Nuffield Department of Women's & Reproductive Health (F.M.H.) and Academic Endocrine Unit, Radcliffe Department of Clinical Medicine (F.M.H., R.V.T.), University of Oxford, Oxford, United Kingdom; Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark (T.C.M., H.B.-O.); Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom (D.T.W.); Department of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria (E.K.); Physiology, School of Medical Sciences and Bosch Institute (R.S.M.) and School of Life & Environmental Sciences, Charles Perkins Centre (A.D.C.), University of Sydney, Sydney, Australia; and School of Biosciences, Cardiff University, Cardiff, United Kingdom (D.R.)
| | - Thor C Møller
- Drug Discovery Biology, Monash Institute of Pharmaceutical Science, Monash University, Parkville, Australia (K.L., T.M.J., A.N.K.); Nuffield Department of Women's & Reproductive Health (F.M.H.) and Academic Endocrine Unit, Radcliffe Department of Clinical Medicine (F.M.H., R.V.T.), University of Oxford, Oxford, United Kingdom; Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark (T.C.M., H.B.-O.); Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom (D.T.W.); Department of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria (E.K.); Physiology, School of Medical Sciences and Bosch Institute (R.S.M.) and School of Life & Environmental Sciences, Charles Perkins Centre (A.D.C.), University of Sydney, Sydney, Australia; and School of Biosciences, Cardiff University, Cardiff, United Kingdom (D.R.)
| | - Donald T Ward
- Drug Discovery Biology, Monash Institute of Pharmaceutical Science, Monash University, Parkville, Australia (K.L., T.M.J., A.N.K.); Nuffield Department of Women's & Reproductive Health (F.M.H.) and Academic Endocrine Unit, Radcliffe Department of Clinical Medicine (F.M.H., R.V.T.), University of Oxford, Oxford, United Kingdom; Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark (T.C.M., H.B.-O.); Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom (D.T.W.); Department of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria (E.K.); Physiology, School of Medical Sciences and Bosch Institute (R.S.M.) and School of Life & Environmental Sciences, Charles Perkins Centre (A.D.C.), University of Sydney, Sydney, Australia; and School of Biosciences, Cardiff University, Cardiff, United Kingdom (D.R.)
| | - Enikö Kallay
- Drug Discovery Biology, Monash Institute of Pharmaceutical Science, Monash University, Parkville, Australia (K.L., T.M.J., A.N.K.); Nuffield Department of Women's & Reproductive Health (F.M.H.) and Academic Endocrine Unit, Radcliffe Department of Clinical Medicine (F.M.H., R.V.T.), University of Oxford, Oxford, United Kingdom; Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark (T.C.M., H.B.-O.); Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom (D.T.W.); Department of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria (E.K.); Physiology, School of Medical Sciences and Bosch Institute (R.S.M.) and School of Life & Environmental Sciences, Charles Perkins Centre (A.D.C.), University of Sydney, Sydney, Australia; and School of Biosciences, Cardiff University, Cardiff, United Kingdom (D.R.)
| | - Rebecca S Mason
- Drug Discovery Biology, Monash Institute of Pharmaceutical Science, Monash University, Parkville, Australia (K.L., T.M.J., A.N.K.); Nuffield Department of Women's & Reproductive Health (F.M.H.) and Academic Endocrine Unit, Radcliffe Department of Clinical Medicine (F.M.H., R.V.T.), University of Oxford, Oxford, United Kingdom; Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark (T.C.M., H.B.-O.); Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom (D.T.W.); Department of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria (E.K.); Physiology, School of Medical Sciences and Bosch Institute (R.S.M.) and School of Life & Environmental Sciences, Charles Perkins Centre (A.D.C.), University of Sydney, Sydney, Australia; and School of Biosciences, Cardiff University, Cardiff, United Kingdom (D.R.)
| | - Rajesh V Thakker
- Drug Discovery Biology, Monash Institute of Pharmaceutical Science, Monash University, Parkville, Australia (K.L., T.M.J., A.N.K.); Nuffield Department of Women's & Reproductive Health (F.M.H.) and Academic Endocrine Unit, Radcliffe Department of Clinical Medicine (F.M.H., R.V.T.), University of Oxford, Oxford, United Kingdom; Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark (T.C.M., H.B.-O.); Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom (D.T.W.); Department of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria (E.K.); Physiology, School of Medical Sciences and Bosch Institute (R.S.M.) and School of Life & Environmental Sciences, Charles Perkins Centre (A.D.C.), University of Sydney, Sydney, Australia; and School of Biosciences, Cardiff University, Cardiff, United Kingdom (D.R.)
| | - Daniela Riccardi
- Drug Discovery Biology, Monash Institute of Pharmaceutical Science, Monash University, Parkville, Australia (K.L., T.M.J., A.N.K.); Nuffield Department of Women's & Reproductive Health (F.M.H.) and Academic Endocrine Unit, Radcliffe Department of Clinical Medicine (F.M.H., R.V.T.), University of Oxford, Oxford, United Kingdom; Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark (T.C.M., H.B.-O.); Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom (D.T.W.); Department of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria (E.K.); Physiology, School of Medical Sciences and Bosch Institute (R.S.M.) and School of Life & Environmental Sciences, Charles Perkins Centre (A.D.C.), University of Sydney, Sydney, Australia; and School of Biosciences, Cardiff University, Cardiff, United Kingdom (D.R.)
| | - Arthur D Conigrave
- Drug Discovery Biology, Monash Institute of Pharmaceutical Science, Monash University, Parkville, Australia (K.L., T.M.J., A.N.K.); Nuffield Department of Women's & Reproductive Health (F.M.H.) and Academic Endocrine Unit, Radcliffe Department of Clinical Medicine (F.M.H., R.V.T.), University of Oxford, Oxford, United Kingdom; Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark (T.C.M., H.B.-O.); Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom (D.T.W.); Department of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria (E.K.); Physiology, School of Medical Sciences and Bosch Institute (R.S.M.) and School of Life & Environmental Sciences, Charles Perkins Centre (A.D.C.), University of Sydney, Sydney, Australia; and School of Biosciences, Cardiff University, Cardiff, United Kingdom (D.R.)
| | - Hans Bräuner-Osborne
- Drug Discovery Biology, Monash Institute of Pharmaceutical Science, Monash University, Parkville, Australia (K.L., T.M.J., A.N.K.); Nuffield Department of Women's & Reproductive Health (F.M.H.) and Academic Endocrine Unit, Radcliffe Department of Clinical Medicine (F.M.H., R.V.T.), University of Oxford, Oxford, United Kingdom; Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark (T.C.M., H.B.-O.); Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom (D.T.W.); Department of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria (E.K.); Physiology, School of Medical Sciences and Bosch Institute (R.S.M.) and School of Life & Environmental Sciences, Charles Perkins Centre (A.D.C.), University of Sydney, Sydney, Australia; and School of Biosciences, Cardiff University, Cardiff, United Kingdom (D.R.)
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8
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Fang Y, Liu L, Liu S, Hu L, Cai W, Wan X, Liu D, He Y, Zhu Z. Calcium-sensing receptor promotes tumor proliferation and migration in human intrahepatic cholangiocarcinoma by targeting ERK signaling pathway. Eur J Pharmacol 2020; 872:172915. [PMID: 31926993 DOI: 10.1016/j.ejphar.2020.172915] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2019] [Revised: 12/18/2019] [Accepted: 01/08/2020] [Indexed: 12/22/2022]
Abstract
The Calcium-sensing receptor (CaSR) is functionally expressed in the biliary epithelial cells and it has been verified to possess various regulatory functions in several different forms of human cancers. But its pathological role in human intrahepatic cholangiocarcinoma (ICC) development remains obscure. Here, we confirmed that CaSR expression was up-regulated in ICC tumor specimens and cell lines, which was positively correlated with number of tumors, lymph node metastasis and poor prognosis of ICC patients. CaSR activation induced by CaCl2 or Calindol (a selective CaSR agonist) markedly facilitated cell proliferation and migration in ICC cells, while knockdown of CaSR or NPS2143 treatment (a CaSR antagonist) dramatically suppressed the above effects. We also demonstrated that alteration of CaSR activity mediated tumorigenesis and growth of ICC in vivo. Mechanistically, CaSR activation could promote cell cycle progression and induce an upregulation of MMP-2 and MMP-9 expression partly via the simulation of ERK1/2 signaling pathway. And further inhibition of ERK pathway significantly suppressed ICC cell viability and migration capacity. Together, our findings shed novel light on the role of CaSR as an oncogene in ICC progression and indicated that modulation of CaSR might serve as a preventive or therapeutic strategy for ICC.
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Affiliation(s)
- Yu Fang
- Department of General Surgery, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui, 230001, China
| | - Liu Liu
- Department of General Surgery, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui, 230001, China
| | - Shaojun Liu
- Department of General Surgery, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui, 230001, China
| | - Lei Hu
- Department of General Surgery, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui, 230001, China
| | - Wei Cai
- Department of General Surgery, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui, 230001, China
| | - Xiao Wan
- Department of General Surgery, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui, 230001, China
| | - Dongliang Liu
- Department of General Surgery, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui, 230001, China
| | - Yiren He
- Department of General Surgery, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui, 230001, China.
| | - Zhiqiang Zhu
- Department of General Surgery, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui, 230001, China.
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9
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Xu J, Zeug A, Riederer B, Yeruva S, Griesbeck O, Daniel H, Tuo B, Ponimaskin E, Dong H, Seidler U. Calcium-sensing receptor regulates intestinal dipeptide absorption via Ca 2+ signaling and IK Ca activation. Physiol Rep 2020; 8:e14337. [PMID: 31960592 PMCID: PMC6971415 DOI: 10.14814/phy2.14337] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Although absorption of di- and tripeptides into intestinal epithelial cells occurs via the peptide transporter 1 (PEPT1, also called solute carrier family 15 member 1 (SLC15A1)), the detailed regulatory mechanisms are not fully understood. We examined: (a) whether dipeptide absorption in villous enterocytes is associated with a rise in cytosolic Ca2+ ([Ca2+ ]cyt ), (b) whether the calcium sensing receptor (CaSR) is involved in dipeptide-elicited [Ca2+ ]cyt signaling, and (c) what potential consequences of [Ca2+ ]cyt signaling may enhance enterocyte dipeptide absorption. Dipeptide Gly-Sar and CaSR agonist spermine markedly raised [Ca2+ ]cyt in villous enterocytes, which was abolished by NPS-2143, a selective CaSR antagonist and U73122, an phospholipase C (PLC) inhibitor. Apical application of Gly-Sar induced a jejunal short-circuit current (Isc), which was reduced by NPS-2143. CaSR expression was identified in the lamina propria and on the basal enterocyte membrane of mouse jejunal mucosa in both WT and Slc15a1-/- animals, but Gly-Sar-induced [Ca2+ ]cyt signaling was significantly decreased in Slc15a1-/- villi. Clotrimazole and TRM-34, two selective blockers of the intermediate conductance Ca2+ -activated K+ channel (IKCa ), but not iberiotoxin, a selective blocker of the large-conductance K+ channel (BKCa ) and apamin, a selective blocker of the small-conductance K+ channel (SKCa ), significantly inhibited Gly-Sar-induced Isc in native tissues. We reveal a novel CaSR-PLC-Ca2+ -IKCa pathway in the regulation of small intestinal dipeptide absorption, which may be exploited as a target for future drug development in human nutritional disorders.
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Affiliation(s)
- Jingyu Xu
- Department of Gastroenterology, Hepatology and EndocrinologyHannover Medical SchoolHannoverGermany
- Research GastroenterologyAffiliated Hospital of Zunyi Medical UniversityZunyiChina
| | - Andre Zeug
- Cellular NeurophysiologyHannover Medical SchoolHannoverGermany
| | - Brigitte Riederer
- Department of Gastroenterology, Hepatology and EndocrinologyHannover Medical SchoolHannoverGermany
| | - Sunil Yeruva
- Department of Gastroenterology, Hepatology and EndocrinologyHannover Medical SchoolHannoverGermany
| | | | - Hannelore Daniel
- Nutritional PhysiologyTechnical University of MunichFreisingGermany
| | - Biguang Tuo
- Research GastroenterologyAffiliated Hospital of Zunyi Medical UniversityZunyiChina
| | | | - Hui Dong
- Department of MedicineUniversity of California, San DiegoLa JollaCAUSA
| | - Ursula Seidler
- Department of Gastroenterology, Hepatology and EndocrinologyHannover Medical SchoolHannoverGermany
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10
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Elajnaf T, Iamartino L, Mesteri I, Müller C, Bassetto M, Manhardt T, Baumgartner-Parzer S, Kallay E, Schepelmann M. Nutritional and Pharmacological Targeting of the Calcium-Sensing Receptor Influences Chemically Induced Colitis in Mice. Nutrients 2019; 11:E3072. [PMID: 31888253 PMCID: PMC6950720 DOI: 10.3390/nu11123072] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Revised: 12/12/2019] [Accepted: 12/13/2019] [Indexed: 01/19/2023] Open
Abstract
The calcium-sensing receptor (CaSR) is the main regulator of extracellular Ca2+ homeostasis. It has diverse functions in different tissues, including the intestines. Intestine-specific knockout of the CaSR renders mice more susceptible to dextran sulphate sodium (DSS)-induced colitis. To test our hypothesis that the CaSR reduces intestinal inflammation, we assessed the effects of nutritional and pharmacological agonists of the CaSR in a colitis model. We treated female Balb/C mice with dietary calcium and protein (nutritional agonists of the CaSR) or pharmacological CaSR modulators (the agonists cinacalcet and GSK3004774, and the antagonist NPS-2143; 10 mg/kg), then induced colitis with DSS. The high-protein diet had a strong pro-inflammatory effect-it shortened the colons (5.3 ± 0.1 cm vs. 6.1 ± 0.2 cm normal diet, p < 0.05), lowered mucin expression and upregulated pro-inflammatory cytokines, such as interferon-γ, (4.2-fold, p < 0.05) compared with the normal diet. Cinacalcet reduced mucin expression, which coincided with an increase in tumor necrosis factor-α (4.4-fold, p < 0.05) and IL-6 (4.9-fold, p < 0.05) in the plasma, compared with vehicle. The CaSR antagonist, NPS-2143, significantly reduced the cumulative inflammation score compared with the vehicle control (35.3 ± 19.1 vs. 21.9 ± 14.3 area under the curve, p < 0.05) and reduced infiltration of inflammatory cells. While dietary modulation of the CaSR had no beneficial effects, pharmacological inhibition of the CaSR may have the potential of a novel add-on therapy in the treatment of inflammatory bowel diseases.
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Affiliation(s)
- Taha Elajnaf
- Center of Pathophysiology Infectiology and Immunology, Medical University of Vienna, Pathophysiology and Allergy Research, Währinger Gürtel, 18-20, 1090 Vienna, Austria; (T.E.); (L.I.); (C.M.); (T.M.); (M.S.)
| | - Luca Iamartino
- Center of Pathophysiology Infectiology and Immunology, Medical University of Vienna, Pathophysiology and Allergy Research, Währinger Gürtel, 18-20, 1090 Vienna, Austria; (T.E.); (L.I.); (C.M.); (T.M.); (M.S.)
| | | | - Christian Müller
- Center of Pathophysiology Infectiology and Immunology, Medical University of Vienna, Pathophysiology and Allergy Research, Währinger Gürtel, 18-20, 1090 Vienna, Austria; (T.E.); (L.I.); (C.M.); (T.M.); (M.S.)
| | - Marcella Bassetto
- School of Pharmacy and Pharmaceutical Sciences, Cardiff University, King Edward VII Avenue, CF10 3NB Cardiff, UK
- Department of Chemistry, College of Science, Swansea University, SA2 8PP Swansea, UK
| | - Teresa Manhardt
- Center of Pathophysiology Infectiology and Immunology, Medical University of Vienna, Pathophysiology and Allergy Research, Währinger Gürtel, 18-20, 1090 Vienna, Austria; (T.E.); (L.I.); (C.M.); (T.M.); (M.S.)
| | | | - Enikö Kallay
- Center of Pathophysiology Infectiology and Immunology, Medical University of Vienna, Pathophysiology and Allergy Research, Währinger Gürtel, 18-20, 1090 Vienna, Austria; (T.E.); (L.I.); (C.M.); (T.M.); (M.S.)
| | - Martin Schepelmann
- Center of Pathophysiology Infectiology and Immunology, Medical University of Vienna, Pathophysiology and Allergy Research, Währinger Gürtel, 18-20, 1090 Vienna, Austria; (T.E.); (L.I.); (C.M.); (T.M.); (M.S.)
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11
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Wang LM, Tang N, Zhong H, Pang LJ, Zhang CJ, He F. [Involvement of interaction between TRPC1 and Orai1 in calcium sensing receptor-mediated calcium influx and nitric oxide generation in human umbilical vein endothelial cells]. Sheng Li Xue Bao 2018; 70:269-280. [PMID: 29926068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The present study was to investigate the role of the interaction between canonical transient receptor potential channel 1 (TRPC1) and calcium release-activated calcium modulator 1 (Orai1) in extracellular Ca2+-sensing receptor (CaR)-induced extracellular Ca2+ influx and nitric oxide (NO) production. Human umbilical vein endothelial cells (HUVECs) were incubated with CaR agonist Spermine [activating store-operated calcium channels (SOC) and receptor-operated calcium channels (ROC)] alone or in combination with the following reagents: CaR negative allosteric modulator Calhex231 plus ROC analogue TPA (activating ROC and blocking SOC), Ro31-8220 (PKC inhibitor that activates SOC and blocks ROC) or Go6967 (PKCs and PKCµ inhibitor that activates SOC and blocks ROC). The protein expressions and co-localization of TRPC1 and Orai1 were determined using immunofluorescent staining. The interaction between TRPC1 and Orai1 was examined by co-immunoprecipitation. We silenced the expressions of their genes in the HUVECs by transfection of constructed TRPC1 and Orai1 shRNA plasmids. Intracellular Ca2+ concentration ([Ca2+]i) was detected using Ca2+ indicator Fura-2/AM, and NO production was determined by DAF-FM staining. The results showed that TRPC1 and Orai1 protein expressions were co-located on the cell membrane of the HUVECs. Compared with Spermine+Ca2+ group, Calhex231+ TPA+Spermine+Ca2+, Ro31-8220+Spermine+Ca2+ and Go6976+Spermine+Ca2+ groups exhibited down-regulated protein expressions of TRPC1 and Orai1 in cytoplasm and decreased co-localization on the cell membrane. Co-immunoprecipitation results showed that the interaction between TRPC1 and Orai1 was reduced by Calhex231 plus TPA, Ro31-8220 or Go6976 addition in the Spermine-stimulated HUVECs. Double knockdown of Trpc1 and Orai1 genes significantly decreased [Ca2+]i level and NO production in all of the Spermine+Ca2+, Calhex231+TPA+Spermine+Ca2+, Ro31-8220+Spermine+Ca2+ and Go6976+Spermine+Ca2+ groups. These results suggest that TRPC1/Orai1 may form a complex that mediates Ca2+ influx and No production via SOC and ROC activation.
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Affiliation(s)
- La-Mei Wang
- Department of Pathophysiology/Key Laboratory of Xinjiang Endemic and Ethnic Diseases, Ministry of Education, Medical College of Shihezi University, Shihezi 832002, China
| | - Na Tang
- Department of Pathophysiology/Key Laboratory of Xinjiang Endemic and Ethnic Diseases, Ministry of Education, Medical College of Shihezi University, Shihezi 832002, China
| | - Hua Zhong
- Department of Pathophysiology/Key Laboratory of Xinjiang Endemic and Ethnic Diseases, Ministry of Education, Medical College of Shihezi University, Shihezi 832002, China
| | - Li-Juan Pang
- Department of Pathophysiology/Key Laboratory of Xinjiang Endemic and Ethnic Diseases, Ministry of Education, Medical College of Shihezi University, Shihezi 832002, China
- Department of Pathology, Medical College of Shihezi University, Shihezi 832002, China
| | - Chun-Jun Zhang
- Department of Pathophysiology/Key Laboratory of Xinjiang Endemic and Ethnic Diseases, Ministry of Education, Medical College of Shihezi University, Shihezi 832002, China
| | - Fang He
- Department of Pathophysiology/Key Laboratory of Xinjiang Endemic and Ethnic Diseases, Ministry of Education, Medical College of Shihezi University, Shihezi 832002, China.
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12
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Bellasi A, Cozzolino M, Malberti F, Cancarini G, Esposito C, Genderini A, Guastoni CM, Ondei P, Pontoriero G, Teatini U, Vezzoli G, Messa P, Locatelli F. [New scenarios in secondary hyperparathyroidism: etelcalcetide. Position paper of Nephrologists form Lombardy]. G Ital Nefrol 2018; 35:2018-vol3-3. [PMID: 29786181] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Bone mineral abnormalities (defined as Chronic Kidney Disease Mineral Bone Disorder; CKD-MBD) are prevalent and associated with a substantial risk burden and poor prognosis in CKD population. Several lines of evidence support the notion that a large proportion of patients receiving maintenance dialysis experience a suboptimal biochemical control of CKD-MBD. Although no study has ever demonstrated conclusively that CKD-MBD control is associated with improved survival, an expanding therapeutic armamentarium is available to correct bone mineral abnormalities. In this position paper of Lombardy Nephrologists, a summary of the state of art of CKD-MBD as well as a summary of the unmet clinical needs will be provided. Furthermore, this position paper will focus on the potential and drawbacks of a new injectable calcimimetic, etelcalcetide, a drug available in Italy since few months ago.
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Affiliation(s)
- Antonio Bellasi
- UOC di Nefrologia e Dialisi, Ospedale Sant'Anna, ASST-Lariana, Como
| | - Mario Cozzolino
- UOC Nefrologia e Dialisi ASST Santi Paolo e Carlo, Presidio San Paolo, Milano
| | - Fabio Malberti
- Struttura Complessa di Nefrologia e Dialisi Istituti Ospedalieri di Cremona
| | - Giovanni Cancarini
- Dipartimento della Cronicità, ASST, Spedali Civili e Università di Brescia
| | - Ciro Esposito
- Struttura Complessa di Nefrologia e Dialisi Fondazione IRCCS S. Maugeri Pavia
| | - Augusto Genderini
- Ospedale Pubblico, Divisione di Nefrologia e Dialisi, Ospedale Caduti Bollatesi, Bollate
| | | | - Patrizia Ondei
- USS Emodialisi, Azienda Ospedaliera Ospedale Papa Giovanni XXIII, Bergamo
| | | | - Ugo Teatini
- Divisione Nefrologia e Dialisi. Ospedale Bollate
| | - Giuseppe Vezzoli
- Unità di Nefrologia e Dialisi, Istituto di Ricovero e cura a carattere scientifico San Raffaele, Milano
| | - Piergiorgio Messa
- Unità Operativa Complessa di Nefrologia e Dialisi, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milano
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13
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Affiliation(s)
- Hua Zhang
- Guelph Food Research Centre , Agriculture and Agri-Food Canada , 93 Stone Road West , Guelph , Ontario N1G 5C9 , Canada
| | - Yoshinori Mine
- Department of Food Science , University of Guelph , Guelph , Ontario N1G 2W1 , Canada
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14
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Li X, Yu L, Asuncion F, Grisanti M, Alexander S, Hensley K, Han CY, Niu QT, Dwyer D, Villasenor K, Stolina M, Dean C, Ominsky MS, Ke HZ, Tomlinson JE, Richards WG. Etelcalcetide (AMG 416), a peptide agonist of the calcium-sensing receptor, preserved cortical bone structure and bone strength in subtotal nephrectomized rats with established secondary hyperparathyroidism. Bone 2017; 105:163-172. [PMID: 28867373 DOI: 10.1016/j.bone.2017.08.026] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Revised: 08/24/2017] [Accepted: 08/28/2017] [Indexed: 10/18/2022]
Abstract
Sustained elevation of parathyroid hormone (PTH) is catabolic to cortical bone, as evidenced by deterioration in bone structure (cortical porosity), and is a major factor for increased fracture risk in chronic kidney disease (CKD). Etelcalcetide (AMG 416), a novel peptide agonist of the calcium-sensing receptor, reduces PTH levels in subtotal nephrectomized (Nx) rats and in hemodialysis patients with secondary hyperparathyroidism (SHPT) in clinical studies; however, effects of etelcalcetide on bone have not been determined. In a rat model of established SHPT with renal osteodystrophy, etelcalcetide or vehicle was administered by subcutaneous (s.c.) injection to subtotal Nx rats with elevated PTH (>750pg/mL) once per day for 6weeks. Sham-operated rats receiving vehicle (s.c.) served as non-SHPT controls. Prior to treatment, significant increases in serum creatinine (2-fold), blood urea nitrogen (BUN, 3-fold), PTH (5-fold), fibroblast growth factor-23 (FGF23; 13-fold) and osteocalcin (12-fold) were observed in SHPT rats compared to non-SHPT controls. Elevations in serum creatinine and BUN were unaffected by treatment with vehicle or etelcalcetide. In contrast, etelcalcetide significantly decreased PTH, FGF23 and osteocalcin, whereas vehicle treatment did not. Cortical bone porosity increased and bone strength decreased in vehicle-treated SHPT rats compared to non-SHPT controls. Cortical bone structure improved and energy to failure was significantly greater in SHPT rats treated with etelcalcetide compared to vehicle. Mineralization lag time and marrow fibrosis were significantly reduced by etelcalcetide. In conclusion, etelcalcetide reduced bone turnover, attenuated mineralization defect and marrow fibrosis, and preserved cortical bone structure and bone strength by lowering PTH in subtotal Nx rats with established SHPT.
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Affiliation(s)
- Xiaodong Li
- Department of Cardiometabolic Disorders, Amgen Inc., Thousand Oaks, CA, USA.
| | - Longchuan Yu
- Department of Cardiometabolic Disorders, Amgen Inc., Thousand Oaks, CA, USA
| | - Frank Asuncion
- Department of Cardiometabolic Disorders, Amgen Inc., Thousand Oaks, CA, USA
| | - Mario Grisanti
- Department of Cardiometabolic Disorders, Amgen Inc., Thousand Oaks, CA, USA
| | - Shawn Alexander
- Department of Cardiometabolic Disorders, Amgen Inc., Thousand Oaks, CA, USA
| | - Kelly Hensley
- Department of Comparative Biology and Safety Sciences, Amgen Inc., Thousand Oaks, CA, USA
| | - Chun-Ya Han
- Department of Cardiometabolic Disorders, Amgen Inc., Thousand Oaks, CA, USA
| | - Qing-Tian Niu
- Department of Cardiometabolic Disorders, Amgen Inc., Thousand Oaks, CA, USA
| | - Denise Dwyer
- Department of Cardiometabolic Disorders, Amgen Inc., Thousand Oaks, CA, USA
| | - Kelly Villasenor
- Department of Cardiometabolic Disorders, Amgen Inc., Thousand Oaks, CA, USA
| | - Marina Stolina
- Department of Cardiometabolic Disorders, Amgen Inc., Thousand Oaks, CA, USA
| | - Charles Dean
- Department of Comparative Biology and Safety Sciences, Amgen Inc., Thousand Oaks, CA, USA
| | - Michael S Ominsky
- Department of Cardiometabolic Disorders, Amgen Inc., Thousand Oaks, CA, USA
| | - Hua Zhu Ke
- Department of Cardiometabolic Disorders, Amgen Inc., Thousand Oaks, CA, USA
| | - James E Tomlinson
- Department of Cardiometabolic Disorders, Amgen Inc., Thousand Oaks, CA, USA
| | - William G Richards
- Department of Cardiometabolic Disorders, Amgen Inc., Thousand Oaks, CA, USA
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15
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Sparks SM, Spearing PK, Diaz CJ, Cowan DJ, Jayawickreme C, Chen G, Rimele TJ, Generaux C, Harston LT, Roller SG. Identification of potent, nonabsorbable agonists of the calcium-sensing receptor for GI-specific administration. Bioorg Med Chem Lett 2017; 27:4673-4677. [PMID: 28916340 DOI: 10.1016/j.bmcl.2017.09.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Revised: 08/25/2017] [Accepted: 09/06/2017] [Indexed: 12/14/2022]
Abstract
Modulation of gastrointestinal nutrient sensing pathways provides a promising a new approach for the treatment of metabolic diseases including diabetes and obesity. The calcium-sensing receptor has been identified as a key receptor involved in mineral and amino acid nutrient sensing and thus is an attractive target for modulation in the intestine. Herein we describe the optimization of gastrointestinally restricted calcium-sensing receptor agonists starting from a 3-aminopyrrolidine-containing template leading to the identification of GI-restricted agonist 19 (GSK3004774).
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Affiliation(s)
- Steven M Sparks
- Enteroendocrine Discovery Performance Unit and Platform Technologies and Science, GlaxoSmithKline, 5 Moore Drive, Research Triangle Park, NC 27709, United States.
| | - Paul K Spearing
- Enteroendocrine Discovery Performance Unit and Platform Technologies and Science, GlaxoSmithKline, 5 Moore Drive, Research Triangle Park, NC 27709, United States
| | - Caroline J Diaz
- Enteroendocrine Discovery Performance Unit and Platform Technologies and Science, GlaxoSmithKline, 5 Moore Drive, Research Triangle Park, NC 27709, United States
| | - David J Cowan
- Enteroendocrine Discovery Performance Unit and Platform Technologies and Science, GlaxoSmithKline, 5 Moore Drive, Research Triangle Park, NC 27709, United States
| | - Channa Jayawickreme
- Enteroendocrine Discovery Performance Unit and Platform Technologies and Science, GlaxoSmithKline, 5 Moore Drive, Research Triangle Park, NC 27709, United States
| | - Grace Chen
- Enteroendocrine Discovery Performance Unit and Platform Technologies and Science, GlaxoSmithKline, 5 Moore Drive, Research Triangle Park, NC 27709, United States
| | - Thomas J Rimele
- Enteroendocrine Discovery Performance Unit and Platform Technologies and Science, GlaxoSmithKline, 5 Moore Drive, Research Triangle Park, NC 27709, United States
| | - Claudia Generaux
- Enteroendocrine Discovery Performance Unit and Platform Technologies and Science, GlaxoSmithKline, 5 Moore Drive, Research Triangle Park, NC 27709, United States
| | - Lindsey T Harston
- Enteroendocrine Discovery Performance Unit and Platform Technologies and Science, GlaxoSmithKline, 5 Moore Drive, Research Triangle Park, NC 27709, United States
| | - Shane G Roller
- Enteroendocrine Discovery Performance Unit and Platform Technologies and Science, GlaxoSmithKline, 5 Moore Drive, Research Triangle Park, NC 27709, United States
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16
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Kojima I, Medina J, Nakagawa Y. Role of the glucose-sensing receptor in insulin secretion. Diabetes Obes Metab 2017; 19 Suppl 1:54-62. [PMID: 28880472 DOI: 10.1111/dom.13013] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Revised: 05/08/2017] [Accepted: 05/16/2017] [Indexed: 11/27/2022]
Abstract
Glucose is a primary stimulator of insulin secretion. It has been thought that glucose exerts its effect by a mechanism solely dependent on glucose metabolism. We show here that glucose induces rapid Ca2+ and cyclic AMP signals in β-cells. These rapid signals are independent of glucose-metabolism and are reproduced by non-metabolizable glucose analogues. These results led us to postulate that glucose activates a cell-surface receptor, namely the glucose-sensing receptor. Rapid signals induced by glucose are blocked by inhibition of a sweet taste receptor subunit T1R3 and a calcium-sensing receptor subunit CaSR. In accordance with these observations, T1R3 and CaSR form a heterodimer. In addition, a heterodimer of T1R3 and CaSR is activated by glucose. These results suggest that a heterodimer of T1R3 and CaSR is a major component of the glucose-sensing receptor. When the glucose-sensing receptor is blocked, glucose-induced insulin secretion is inhibited. Also, ATP production is significantly attenuated by the inhibition of the receptor. Conversely, stimulation of the glucose-sensing receptor by either artificial sweeteners or non-metabolizable glucose analogue increases ATP. Hence, the glucose-sensing receptor signals promote glucose metabolism. Collectively, glucose activates the cell-surface glucose-sensing receptor and promotes its own metabolism. Glucose then enters the cells and is metabolized through already activated metabolic pathways. The glucose-sensing receptor is a key molecule regulating the action of glucose in β-cells.
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MESH Headings
- Animals
- Calcium Signaling
- Cyclic AMP/metabolism
- Dimerization
- Enzyme Activation
- Gene Expression Regulation
- Glucose/metabolism
- Humans
- Insulin/metabolism
- Insulin Secretion
- Insulin-Secreting Cells/enzymology
- Insulin-Secreting Cells/metabolism
- Models, Biological
- Protein Kinase C/chemistry
- Protein Kinase C/metabolism
- Protein Multimerization
- Receptors, Calcium-Sensing/agonists
- Receptors, Calcium-Sensing/chemistry
- Receptors, Calcium-Sensing/genetics
- Receptors, Calcium-Sensing/metabolism
- Receptors, Cell Surface/agonists
- Receptors, Cell Surface/chemistry
- Receptors, Cell Surface/genetics
- Receptors, Cell Surface/metabolism
- Receptors, G-Protein-Coupled/agonists
- Receptors, G-Protein-Coupled/chemistry
- Receptors, G-Protein-Coupled/genetics
- Receptors, G-Protein-Coupled/metabolism
- Second Messenger Systems
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Affiliation(s)
- Itaru Kojima
- Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Japan
| | - Johan Medina
- Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Japan
| | - Yuko Nakagawa
- Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Japan
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Chiarini A, Armato U, Liu D, Dal Prà I. Calcium-Sensing Receptor Antagonist NPS 2143 Restores Amyloid Precursor Protein Physiological Non-Amyloidogenic Processing in Aβ-Exposed Adult Human Astrocytes. Sci Rep 2017; 7:1277. [PMID: 28455519 PMCID: PMC5430644 DOI: 10.1038/s41598-017-01215-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Accepted: 03/27/2017] [Indexed: 12/11/2022] Open
Abstract
Physiological non-amyloidogenic processing (NAP) of amyloid precursor holoprotein (hAPP) by α-secretases (e.g., ADAM10) extracellularly sheds neurotrophic/neuroprotective soluble (s)APPα and precludes amyloid-β peptides (Aβs) production via β-secretase amyloidogenic processing (AP). Evidence exists that Aβs interact with calcium-sensing receptors (CaSRs) in human astrocytes and neurons, driving the overrelease of toxic Aβ42/Aβ42-os (oligomers), which is completely blocked by CaSR antagonist (calcilytic) NPS 2143. Here, we investigated the mechanisms underlying NPS 2143 beneficial effects in human astrocytes. Moreover, because Alzheimer's disease (AD) involves neuroinflammation, we examined whether NPS 2143 remained beneficial when both fibrillary (f)Aβ25-35 and a microglial cytokine mixture (CMT) were present. Thus, hAPP NAP prevailed over AP in untreated astrocytes, which extracellularly shed all synthesized sAPPα while secreting basal Aβ40/42 amounts. Conversely, fAβ25-35 alone dramatically reduced sAPPα extracellular shedding while driving Aβ42/Aβ42-os oversecretion that CMT accelerated but not increased, despite a concurring hAPP overexpression. NPS 2143 promoted hAPP and ADAM10 translocation to the plasma membrane, thereby restoring sAPPα extracellular shedding and fully suppressing any Aβ42/Aβ42-os oversecretion, but left hAPP expression unaffected. Therefore, as anti-AD therapeutics calcilytics support neuronal viability by safeguarding astrocytes neurotrophic/neuroprotective sAPPα shedding, suppressing neurons and astrocytes Aβ42/Aβ42-os build-up/secretion, and remaining effective even under AD-typical neuroinflammatory conditions.
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Affiliation(s)
- Anna Chiarini
- Human Histology & Embryology Unit, Medical School, University of Verona, Verona, Venetia, Italy.
| | - Ubaldo Armato
- Human Histology & Embryology Unit, Medical School, University of Verona, Verona, Venetia, Italy
| | - Daisong Liu
- The Third Xiangya Hospital of Central South University, Department of Plastic Surgery, Changsha, Hunan, China
| | - Ilaria Dal Prà
- Human Histology & Embryology Unit, Medical School, University of Verona, Verona, Venetia, Italy.
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18
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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. Sci Adv 2016; 2:e1600241. [PMID: 27386547 PMCID: PMC4928972 DOI: 10.1126/sciadv.1600241] [Citation(s) in RCA: 92] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [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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Abstract
The actions of extracellular Ca(2+) in regulating parathyroid gland and kidney functions are mediated by the extracellular calcium receptor (CaR), a G protein-coupled receptor. The CaR is one of the essential molecules maintaining systemic Ca(2+) homeostasis and is a molecular target for drugs useful in treating bone and mineral disorders. Ligands that activate the CaR are termed calcimimetics and are classified as either agonists (type I) or positive allosteric modulators (type II); calcimimetics inhibit the secretion of parathyroid hormone (PTH). Cinacalcet is a type II calcimimetic that is used to treat secondary hyperparathyroidism in patients receiving dialysis and to treat hypercalcemia in some forms of primary hyperparathyroidism. The use of cinacalcet among patients with secondary hyperparathyroidism who are managed with dialysis effectively lowers circulating PTH levels, reduces serum phosphorus and FGF23 concentrations, improves bone histopathology, and may diminish skeletal fracture rates and the need for parathyroidectomy. A second generation type II calcimimetic (AMG 416) is currently under regulatory review. Calcilytics are CaR antagonists that stimulate the secretion of PTH. Several calcilytic compounds have been evaluated as orally active anabolic therapies for postmenopausal osteoporosis but clinical development of all of them has been abandoned because they lacked clinical efficacy. Calcilytics might be repurposed for new indications like autosomal dominant hypocalcemia or other disorders beyond those involving systemic Ca(2+) homeostasis.
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Affiliation(s)
- E F Nemeth
- MetisMedica, 13 Poplar Plains Road, Toronto, ON, M4V 2M7, Canada.
| | - W G Goodman
- , 22102 Palais Place, Calabasas, CA, 91302, USA
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20
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Abstract
Management of acute diarrhea remains a global challenge, particularly in resource-limiting countries. Oral rehydration solution (ORS), a passive rehydrating therapy developed approximately 40 years ago, remains the mainstay treatment. Although ORS is effective for hydration, since it does not inhibit enterotoxin-mediated excessive secretion, reduced absorption and compromised barrier function - the primary mechanisms of diarrhea, ORS does not offer a rapid relief of diarrhea symptom. There are a few alternative therapies available, yet the use of these drugs is limited by their expense, lack of availability and/or safety concerns. Novel anti-diarrheal therapeutic approaches, particularly those simple affordable therapies, are needed. This article explores intestinal calcium-sensing receptor (CaSR), a newly uncovered target for therapy of diarrhea. Unlike others, targeting this host antidiarrheal receptor system appears “all-inclusive”: it is anti-secretory, pro-absorptive, anti-motility, and anti-inflammatory. Thus, activating CaSR reverses changes of both secretory and inflammatory diarrheas. Considering its unique property of using simple nutrients such as calcium, polyamines, and certain amino acids/oligopeptides as activators, it is possible that through targeting of CaSR with a combination of specific nutrients, novel oral rehydrating solutions that are inexpensive and practical to use in all countries may be developed.
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21
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Bushinsky DA, Block GA, Martin KJ, Bell G, Huang S, Sun Y, Spiegel DM, Walsh L, Mix TC, Kewalramani R. Treatment of Secondary Hyperparathyroidism: Results of a Phase 2 Trial Evaluating an Intravenous Peptide Agonist of the Calcium-Sensing Receptor. Am J Nephrol 2015; 42:379-88. [PMID: 26684933 DOI: 10.1159/000442754] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Accepted: 11/21/2015] [Indexed: 11/19/2022]
Abstract
BACKGROUND/AIMS This study evaluated the efficacy and safety of AMG416 (etelcalcitide), a novel peptide agonist of the calcium (Ca)-sensing receptor given intravenously (IV) after each hemodialysis session for the treatment of secondary hyperparathyroidism (SHPT). METHODS Adult subjects with SHPT on hemodialysis enrolled in a 12-week, dose titration (parent) study followed by an open-label extension phase. AMG416 was administered IV, thrice weekly starting at 5 mg/session and titrated based on the subject's parathyroid hormone (PTH) and albumin-corrected Ca (cCa) to target a PTH of 150-300 pg/ml. Efficacy (percent PTH change from baseline to the efficacy analysis period during the parent study) and safety (open-label extension phase) endpoints were evaluated. RESULTS Baseline (n = 37) mean (standard error [SE]) PTH was 853 (106 pg/ml). The mean (95% CI) percent change from baseline to the efficacy analysis period in PTH concentration was -53.6% (-60.8, -46.4). The proportion of subjects with ≥30% reduction in PTH from baseline to the efficacy assessment period (EAP) was 89% (32/36; 95% CI 73.9, 96.9). Results by the baseline PTH subgroup (≤700 vs. >700 pg/ml) were comparable for both analyses. The proportion of subjects achieving a PTH ≤300 pg/ml was 56% (n = 20/36) at the efficacy assessment period. The mean (SE) percent changes from baseline to EAP were observed for cCa -15% (1.0%) and phosphorus -10% (3.3%). Adverse events were mild to moderate in severity. The PTH reductions achieved in the parent study were maintained in the open-label extension phase. CONCLUSION AMG416 was well tolerated and appears to be an effective agent for the treatment of SHPT in patients on hemodialysis.
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22
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Molostvov G, Hiemstra TF, Fletcher S, Bland R, Zehnder D. Arterial Expression of the Calcium-Sensing Receptor Is Maintained by Physiological Pulsation and Protects against Calcification. PLoS One 2015; 10:e0138833. [PMID: 26436544 PMCID: PMC4593585 DOI: 10.1371/journal.pone.0138833] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Accepted: 09/03/2015] [Indexed: 12/19/2022] Open
Abstract
Vascular calcification (VC) is common in chronic kidney disease (CKD) and contributes to cardiovascular mortality. The calcium-sensing receptor (CaSR) is present in human artery, senses extracellular calcium and may directly modulate VC. Objective: to investigate the association between arterial cyclic strain, CaSR expression and VC. Methods and Results: human aortic smooth muscle cells (HAoSMC) were cultured under static or strained conditions, with exposure to CaSR agonists, the calcimimetic R568, and after CaSR silencing and over-expression. High extracellular calcium reduced CaSR expression and promoted osteochondrogenic transformation and calcium deposition. This was partially prevented by cyclic strain and exposure to R568. CaSR silencing enhanced calcification and osteochondrogenic transformation, whereas CaSR over-expression attenuated this procalcific response, demonstrating a central role for the CaSR in the response to cyclic strain and regulation of VC. In arterial explants from CKD patients (n = 11) and controls (n = 9), exposure to R568 did not significantly alter calcium deposition, osteochondrogenic markers or total artery calcium content. Conclusions: physiological mechanical strain is important for arterial homeostasis and may protect arteries from VC. The beneficial effects of cyclic strain may be mediated via the CaSR.
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MESH Headings
- Adult
- Aged
- Aorta/cytology
- Aorta/metabolism
- Calcium/metabolism
- Calcium/pharmacology
- Cells, Cultured
- Chondrogenesis/drug effects
- Core Binding Factor Alpha 1 Subunit/biosynthesis
- Core Binding Factor Alpha 1 Subunit/genetics
- Extracellular Matrix Proteins/biosynthesis
- Extracellular Matrix Proteins/genetics
- Female
- Gene Expression Regulation/drug effects
- Humans
- Male
- Middle Aged
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/metabolism
- Myocytes, Smooth Muscle/drug effects
- Myocytes, Smooth Muscle/metabolism
- Osteoblasts/cytology
- Osteogenesis/drug effects
- Phenethylamines/pharmacology
- Phosphoproteins/biosynthesis
- Phosphoproteins/genetics
- Propylamines/pharmacology
- Pulsatile Flow/physiology
- Receptors, Calcium-Sensing/agonists
- Receptors, Calcium-Sensing/antagonists & inhibitors
- Receptors, Calcium-Sensing/genetics
- Receptors, Calcium-Sensing/physiology
- Recombinant Fusion Proteins/biosynthesis
- Stress, Mechanical
- Transfection
- Vascular Calcification/physiopathology
- Vascular Calcification/prevention & control
- Young Adult
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Affiliation(s)
- Guerman Molostvov
- The Clinical Sciences Research Laboratory, Warwick Medical School, University of Warwick, Coventry, United Kingdom
| | - Thomas F. Hiemstra
- School of Clinical Medicine, University of Cambridge, Cambridge, United Kingdom
- Cambridge Clinical Trials Unit, Addenbrooke’s Hospital, Cambridge, United Kingdom
- * E-mail:
| | - Simon Fletcher
- Department of Nephrology, University Hospital Coventry and Warwickshire, Coventry, United Kingdom
| | - Rosemary Bland
- The Clinical Sciences Research Laboratory, Warwick Medical School, University of Warwick, Coventry, United Kingdom
| | - Daniel Zehnder
- The Clinical Sciences Research Laboratory, Warwick Medical School, University of Warwick, Coventry, United Kingdom
- Department of Nephrology, University Hospital Coventry and Warwickshire, Coventry, United Kingdom
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23
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Wang P, Wang L, Wang S, Li S, Li Y, Zhang L. Effects of calcium-sensing receptors on apoptosis in rat hippocampus during hypoxia/reoxygenation through the ERK1/2 pathway. Int J Clin Exp Pathol 2015; 8:10808-10815. [PMID: 26617793 PMCID: PMC4637608] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Accepted: 06/26/2015] [Indexed: 06/05/2023]
Abstract
OBJECTIVES To explore the effects of calcium-sensing receptors (CaSR) on apoptosis in rat hippocampus during hypoxia/reoxygenation (H/R). METHODS After rat hippocampus was isolated, the cultures were subjected to H/R, and meanwhile gadolinium chloride (GdCl3, agonist of CaSR) and NPS 2390 (antagonists of CaSR) were added to reperfusion solution. The number of hippocampal neuron, cell viability and apoptosis rate were determined by inverted microscope, 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) and flow cytometer (FCM), respectively. Besides, caspase-3, Bax, cytochrome C (Cyt-c), extracellular signal-regulated protein kinase (ERK) 1/2, pERK1/2, P38 and pP38 were analyzed by Western blotting. RESULTS The hippocampal neuron number and cell viability were significantly decreased during H/R, and were further significantly reduced when co-treatment with CaSR agonist GdCl3. But the effects of GdCl3 were attenuated by NPS-2390. Whereas, apoptosis rate, the expression level of caspase-3, Bax and Cyt-c were all significantly increased under H/R condition, and was further significantly increased by GdCl3, but were reversed by NPS-2390 (P < 0.05). Moreover, there were no significant differences in expression of ERK1/2, P38 and pP38 among different groups. However, the expression of pERK1/2 was significantly increased during H/R, but was significantly reduced by NPS 2390 (P < 0.05). CONCLUSION The results suggest that CaSR might play significant roles in the induction of hippocampus apoptosis in rat during H/R through phosphorylation of ERK1/2.
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Affiliation(s)
- Peng Wang
- Department of Anesthesiology, Affiliated Hospital of Qingdao University Qingdao, Shandong, P. R. China
| | - Li Wang
- Department of Anesthesiology, Affiliated Hospital of Qingdao University Qingdao, Shandong, P. R. China
| | - Shilei Wang
- Department of Anesthesiology, Affiliated Hospital of Qingdao University Qingdao, Shandong, P. R. China
| | - Shuhong Li
- Department of Anesthesiology, Affiliated Hospital of Qingdao University Qingdao, Shandong, P. R. China
| | - Yu Li
- Department of Anesthesiology, Affiliated Hospital of Qingdao University Qingdao, Shandong, P. R. China
| | - Lin Zhang
- Department of Anesthesiology, Affiliated Hospital of Qingdao University Qingdao, Shandong, P. R. China
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Abstract
Diarrhoeal disease remains a major health burden worldwide. Secretory diarrhoeas are caused by certain bacterial and viral infections, inflammatory processes, drugs and genetic disorders. Fluid secretion across the intestinal epithelium in secretory diarrhoeas involves multiple ion and solute transporters, as well as activation of cyclic nucleotide and Ca(2+) signalling pathways. In many secretory diarrhoeas, activation of Cl(-) channels in the apical membrane of enterocytes, including the cystic fibrosis transmembrane conductance regulator and Ca(2+)-activated Cl(-) channels, increases fluid secretion, while inhibition of Na(+) transport reduces fluid absorption. Current treatment of diarrhoea includes replacement of fluid and electrolyte losses using oral rehydration solutions, and drugs targeting intestinal motility or fluid secretion. Therapeutics in the development pipeline target intestinal ion channels and transporters, regulatory proteins and cell surface receptors. This Review describes pathogenic mechanisms of secretory diarrhoea, current and emerging therapeutics, and the challenges in developing antidiarrhoeal therapeutics.
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Affiliation(s)
- Jay R Thiagarajah
- Division of Gastroenterology, Hepatology and Nutrition, Children's Hospital Boston, Harvard Medical School, 300 Longwood Avenue, Boston, MA 02115, USA
| | - Mark Donowitz
- Departments of Physiology and Medicine, Division of Gastroenterology, Johns Hopkins University School of Medicine, Ross 925, 720 Rutland Avenue, Baltimore, MD 21205, USA
| | - Alan S Verkman
- Departments of Medicine and Physiology, 1246 Health Sciences East Tower, University of California, 500 Parnassus Avenue, San Francisco, CA 94143, USA
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25
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Abstract
Secondary hyperparathyroidism (SHPT) is an important complication of advanced chronic kidney disease (CKD). Cinacalcet, an allosteric modulator of the calcium-sensing receptor (CaSR) expressed in parathyroid glands, is the only calcimimetic approved to treat SHPT in patients on dialysis. By enhancing CaSR sensitivity for plasma extracellular calcium (Ca(2+)0), cinacalcet reduces serum parathyroid hormone, Ca(2+)0, and serum inorganic phosphorous concentrations, allowing better control of SHPT and CKD-mineral and bone disorders. Of interest, the CaSR also is expressed in a variety of tissues where its activation regulates diverse cellular processes, including secretion, apoptosis, and proliferation. Thus, the existence of potential off-target effects of cinacalcet cannot be neglected. This review summarizes our current knowledge concerning the potential role(s) of the CaSR expressed in various tissues in CKD-related disorders, independently of parathyroid hormone control.
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Affiliation(s)
- Ziad A Massy
- Inserm U-1088, University of Picardie Jules Verne, Amiens, France; Division of Nephrology, Ambroise Paré Hospital, Paris-Ile-de-France-Ouest University (University of Versailles Saint-Quentin-En-Yvelines), Paris-Boulogne Billancourt, France.
| | - Lucie Hénaut
- Inserm U-1088, University of Picardie Jules Verne, Amiens, France
| | - Tobias E Larsson
- Department of Clinical Science, Intervention and Technology, Renal Unit, Karolinska Institutet, Stockholm, Sweden; Department of Nephrology, Karolinska University Hospital, Stockholm, Sweden
| | - Marc G Vervloet
- Department of Nephrology and Institute of Cardiovascular Research VU (Institute for Cardiovascular Research of the Vrije Universiteit of Amsterdam), VU University Medical Center, Amsterdam, The Netherlands
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26
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Endo I. [Bone and Nutrition. A prospect of calcium sensing receptor]. Clin Calcium 2015; 25:1029-1036. [PMID: 26119316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Following the discovery of the calcium-sensing receptor (CaSR) in 1993, its pivotal role in disorders of calcium homeostasis was demonstrated. Compelling evidence suggests that the CaSR plays multiple roles extending well beyond not only regulating the level of extracellular Ca(2+), but also controlling diverse and crucial roles in human physiology and pathophysiology. This review covers current knowledge of the role of the CaSR in disorders of calcium homeostasis (familial hypocalciuric hypercalcemia, neonatal severe hyperparathyroidism, autosomal dominant hypocalcemia, primary and secondary hyperparathyroidism, hypercalcemia of malignancy) as well as unrelated diseases such as breast and colorectal cancer, Alzheimer's disease and pancreatitis. In addition, it examines the use or potential use of CaSR agonists or antagonists in the management of disorders as diverse as hyperparathyroidism and Alzheimer's disease.
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Affiliation(s)
- Itsuro Endo
- Department of Hematology, Endocrinology and Metabolism, Institute of Biomedical Sciences, Tokushima University Graduate School, Japan
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27
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Bell G, Huang S, Martin KJ, Block GA. A randomized, double-blind, phase 2 study evaluating the safety and efficacy of AMG 416 for the treatment of secondary hyperparathyroidism in hemodialysis patients. Curr Med Res Opin 2015; 31:943-52. [PMID: 25786369 DOI: 10.1185/03007995.2015.1031731] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
OBJECTIVE Secondary hyperparathyroidism (SHPT) is a frequent complication of chronic kidney disease. We evaluated AMG 416, a long-acting peptide agonist of the calcium-sensing receptor, to assess its safety, tolerability, and efficacy and to determine a safe and effective starting dose for subsequent phase 2 studies. The study was not designed to titrate AMG 416 dosing to achieve a specific PTH treatment goal. RESEARCH DESIGN AND METHODS This is a multicenter, double-blind, randomized, placebo-controlled, dose-escalation study designed to evaluate the safety and efficacy of AMG 416 administered thrice weekly by IV bolus at the end of hemodialysis for up to 4 weeks. Eligible subjects were enrolled in one of three cohorts and treated with 5 mg of AMG 416 or placebo for 2 weeks (Cohort 1) or 5 or 10 mg of AMG 416 or placebo for 4 weeks (Cohorts 2 and 3). The primary endpoint was mean percentage change from baseline in PTH during the efficacy assessment phase (EAP) in Cohorts 2 and 3. RESULTS Analysis of the primary endpoint showed that treatment with AMG 416 at 10 mg (Cohort 2) and 5 mg (Cohort 3) for up to 4 weeks resulted in mean 49.4% and 33.0% reductions from baseline in PTH during the efficacy assessment phase, respectively (p < 0.05 for both cohorts compared to placebo group within the cohort). A substantial proportion of subjects treated with AMG 416 achieved PTH ≤300 pg/mL and ≥30% reduction in PTH from baseline in both cohorts. The observed decreases in serum-corrected calcium were well tolerated and serum phosphate levels also tended to decrease. CONCLUSIONS The present clinical findings support the continued development of AMG 416 as a treatment for SHPT in hemodialysis patients.
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28
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Meng K, Xu J, Zhang C, Zhang R, Yang H, Liao C, Jiao J. Calcium sensing receptor modulates extracellular calcium entry and proliferation via TRPC3/6 channels in cultured human mesangial cells. PLoS One 2014; 9:e98777. [PMID: 24905090 PMCID: PMC4048219 DOI: 10.1371/journal.pone.0098777] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2014] [Accepted: 05/07/2014] [Indexed: 12/31/2022] Open
Abstract
Calcium-sensing receptor (CaSR) has been demonstrated to be present in several tissues and cells unrelated to systemic calcium homeostasis, where it regulates a series of diverse cellular functions. A previous study indicated that CaSR is expressed in mouse glomerular mesangial cells (MCs), and stimulation of CaSR induces cell proliferation. However, the signaling cascades initiated by CaSR activation in MCs are currently unknown. In this study, our data demonstrate that CaSR mRNA and protein are expressed in a human mesangial cell line. Activating CaSR with high extracellular Ca2+ concentration ([Ca2+]o) or spermine induces a phospholipase C (PLC)-dependent increase in intracellular Ca2+ concentration ([Ca2+]i). Interestingly, the CaSR activation-induced increase in [Ca2+]i results not only from intracellular Ca2+ release from internal stores but also from canonical transient receptor potential (TRPC)-dependent Ca2+ influx. This increase in Ca2+ was attenuated by treatment with a nonselective TRPC channel blocker but not by treatment with a voltage-gated calcium blocker or Na+/Ca2+ exchanger inhibitor. Furthermore, stimulation of CaSR by high [Ca2+]o enhanced the expression of TRPC3 and TRPC6 but not TRPC1 and TRPC4, and siRNA targeting TRPC3 and TRPC6 attenuated the CaSR activation-induced [Ca2+]i increase. Further experiments indicate that 1-oleoyl-2-acetyl-sn-glycerol (OAG), a known activator of receptor-operated calcium channels, significantly enhances the CaSR activation-induced [Ca2+]i increase. Moreover, under conditions in which intracellular stores were already depleted with thapsigargin (TG), CaSR agonists also induced an increase in [Ca2+]i, suggesting that calcium influx stimulated by CaSR agonists does not require the release of calcium stores. Finally, our data indicate that pharmacological inhibition and knock down of TRPC3 and TRPC6 attenuates the CaSR activation-induced cell proliferation in human MCs. With these data, we conclude that CaSR activation mediates Ca2+ influx and cell proliferation via TRPC3 and TRPC6 in human MCs.
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Affiliation(s)
- Kexin Meng
- Department of Nephrology, The Second Affiliated Hospital, Harbin Medical University, Harbin, China
| | - Jia Xu
- Department of Nephrology, The Fourth Affiliated Hospital, Harbin Medical University, Harbin, China
| | - Chengwei Zhang
- Department of Nephrology, The Second Affiliated Hospital, Harbin Medical University, Harbin, China
| | - Rui Zhang
- Department of Nephrology, The Second Affiliated Hospital, Harbin Medical University, Harbin, China
| | - He Yang
- Department of Nephrology, The Second Affiliated Hospital, Harbin Medical University, Harbin, China
| | - Chang Liao
- Department of Nephrology, The Second Affiliated Hospital, Harbin Medical University, Harbin, China
| | - Jundong Jiao
- Department of Nephrology, The Second Affiliated Hospital, Harbin Medical University, Harbin, China
- Institute of Nephrology, Harbin Medical University, Harbin, China
- * E-mail:
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Nørskov-Lauritsen L, Thomsen ARB, Bräuner-Osborne H. G protein-coupled receptor signaling analysis using homogenous time-resolved Förster resonance energy transfer (HTRF®) technology. Int J Mol Sci 2014; 15:2554-72. [PMID: 24531140 PMCID: PMC3958867 DOI: 10.3390/ijms15022554] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Revised: 01/17/2014] [Accepted: 01/28/2014] [Indexed: 11/18/2022] Open
Abstract
Studying multidimensional signaling of G protein-coupled receptors (GPCRs) in search of new and better treatments requires flexible, reliable and sensitive assays in high throughput screening (HTS) formats. Today, more than half of the detection techniques used in HTS are based on fluorescence, because of the high sensitivity and rich signal, but quenching, optical interferences and light scattering are serious drawbacks. In the 1990s the HTRF® (Cisbio Bioassays, Codolet, France) technology based on Förster resonance energy transfer (FRET) in a time-resolved homogeneous format was developed. This improved technology diminished the traditional drawbacks. The optimized protocol described here based on HTRF® technology was used to study the activation and signaling pathways of the calcium-sensing receptor, CaSR, a GPCR responsible for maintaining calcium homeostasis. Stimulation of the CaSR by agonists activated several pathways, which were detected by measuring accumulation of the second messengers D-myo-inositol 1-phosphate (IP1) and cyclic adenosine 3',5'-monophosphate (cAMP), and by measuring the phosphorylation of extracellular signal-regulated kinase 1 and 2 (ERK1/2). Here we show how an optimized HTRF® platform with numerous advantages compared to previous assays provides a substantial and robust mode of investigating GPCR signaling. It is furthermore discussed how these assays can be optimized and miniaturized to meet HTS requirements and for screening compound libraries.
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Affiliation(s)
- Lenea Nørskov-Lauritsen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Fruebjergvej 3, Mailbox 10, Copenhagen DK-2100, Denmark.
| | - Alex Rojas Bie Thomsen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Fruebjergvej 3, Mailbox 10, Copenhagen DK-2100, Denmark.
| | - Hans Bräuner-Osborne
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Fruebjergvej 3, Mailbox 10, Copenhagen DK-2100, Denmark.
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Abstract
The classical model of G protein-coupled receptor (GPCR) activation is the two-state model, in which the GPCR exists in equilibrium between an active and inactive state. Based on this model, GPCR ligands have been classified as agonists, inverse agonists, or antagonists depending on their actions in shifting this equilibrium. Recently, however, accumulating evidence has indicated that GPCRs may exist in multiple active and inactive conformational states. In this situation, each ligand recognizes and stabilizes a specific conformation of the GPCR, leading to a set of specific biological effects. Based on this new model, a unique agonist or a combination of the usual agonist and an allosteric modulator may enable activation of a specific signaling pathway via a GPCR that activates multiple signals (biased agonism, functional selectivity). The calcium-sensing receptor autoantibody that we have identified in the serum of a patient with acquired hypocalciuric hypercalcemia (AHH) is the first example of a biased allosteric modulator of a GPCR working in a pathophysiological context. Our findings may indicate the presence of physiological allosteric modulators and provide new directions for the future drug development.
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Affiliation(s)
- Noriko Makita
- Department of Endocrinology and Nephrology, The University of Tokyo School of Medicine, Tokyo 113-8655 Japan
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Hayashi S, Kurata N, Kitahirachi E, Nishimura Y, Amagase K, Yano T, Takeuchi K. Cinacalcet, a calcimimetic, prevents nonsteroidal antiinflammatory drug-induced small intestinal damage in rats. J Physiol Pharmacol 2013; 64:453-463. [PMID: 24101391] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Received: 01/17/2013] [Accepted: 08/26/2013] [Indexed: 06/02/2023]
Abstract
The extracellular calcium-sensing receptor (CaSR), a G protein-coupled cell receptor cloned from bovine parathyroid, has been demonstrated to play a regulatory role in various functions of the gastrointestinal tract. In the present study, we examined the effect of cinacalcet, a drug that acts as a calcimimetic through the allosteric activation of CaSR, on the loxoprofen-induced small intestinal lesions and investigated the mechanisms involved in the protective action. Male Sprague-Dawley rats were used without fasting. The animals were administered loxoprofen p.o. and euthanized 24 hours later and the intestinal mucosa was examined for lesions. Cinacalcet was given p.o. twice, 30 min before and 6 h after loxoprofen. Loxoprofen caused hemorrhagic lesions in the small intestine, accompanied by the upregulation of enterobacterial invasion, myeloperoxidase (MPO) activity and inducible nitric oxide synthase (iNOS)/tumor necrosis factor α (TNF-α) expression as well as the downregulation of Muc2 expression. Prior administration of cinacalcet dose-dependently and significantly reduced the severity of these lesions in response to loxoprofen, with concomitant suppression of the changes in bacterial invasion, iNOS/TNF-α as well as Muc2 expression, and myeloperoxidase activity. Cinacalcet also significantly reversed a decrease in mucus secretion and fluid secretion in the small intestine caused by loxoprofen, but had no effect on the intestinal hypermotility or prostaglandin E₂ deficiency caused by loxoprofen. These results suggest that cinacalcet protects the small intestine against loxoprofen-induced damage, and this effect may be functionally associated with an increase in fluid secretion and a reversal of downregulation of Muc2 expression caused by loxoprofen, resulting in suppression of bacterial invasion and iNOS/TNF-α expression, the major pathogenic events in nonsteroidal antiinflammatory drugs-induced small intestinal ulceration.
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Affiliation(s)
- S Hayashi
- Department of Pharmacology and Experimental Therapeutics, Division of Pathological Sciences, Kyoto Pharmaceutical University, Misasagi, Yamashina, Kyoto, Japan.
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Abstract
The calcium-sensing receptor (CaSR) plays a pivotal role in regulating systemic Ca(2+) homeostasis and is a target for drugs designed to treat certain disorders of bone and mineral metabolism. Calcimimetics are agonists or positive allosteric modulators of the CaSR; they inhibit parathyroid hormone (PTH) secretion and stimulate renal Ca(2+) excretion. The first calcimimetic drug is cinacalcet, a positive allosteric modulator of the CaSR that is approved for treating secondary hyperparathyroidism (HPT) in patients on renal replacement therapy and for some forms of primary HPT characterized by clinically significant hypercalcemia. Cinacalcet is also being investigated as a therapy for other hypercalcemic conditions and certain hypophosphatemic disorders. Calcilytics are CaSR inhibitors that stimulate the secretion of PTH and decrease renal excretion of Ca(2+). Although calcilytics have failed thus far as anabolic therapies for osteoporosis, they are currently being evaluated as novel therapies for new indications involving hypocalcemia and/or hypercalciuria.
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Affiliation(s)
- Edward F Nemeth
- MetisMedica, 13 Poplar Plains Road, Toronto, ON M4V 2M7, Canada.
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Bellasi A, Reiner M, Pétavy F, Goodman W, Floege J, Raggi P. Presence of valvular calcification predicts the response to cinacalcet: data from the ADVANCE study. J Heart Valve Dis 2013; 22:391-399. [PMID: 24151766] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
BACKGROUND AND AIM OF THE STUDY Cardiac valve calcification (CVC) and coronary artery calcification (CAC) appear to be linked pathogenetically, and both are associated with a poor prognosis among patients with chronic kidney disease on dialysis (CKD-5D). Little is known, however, about factors that affect the progression of CVC and CAC. METHODS A post-hoc analysis was performed of the ADVANCE study to assess whether patients with CVC are more prone to CAC progression, and whether CVC predicts the response to different treatments for secondary hyperparathyroidism. RESULTS Subjects were randomized to treatment with either cinacalcet and low doses of vitamin D analogs or larger, varying doses of vitamin D. Among 235 subjects, aortic valve or mitral valve calcification was detected in 108 (46%) and 118 (50%), respectively; 69 subjects (29%) had calcification of both valves. CVC was associated both with baseline CAC and CAC progression (p < 0.05). Subjects with aortic valve calcification who were treated with cinacalcet and low doses of vitamin D experienced less progression of CAC than subjects given larger, varying doses of vitamin D (adjusted OR: 0.26; 95% CI: 0.10, 0.64). This effect was greater in subjects with larger CAC burden at baseline. CONCLUSION The study findings suggest that CVC is a predictor of CAC progression and, potentially, of greater cardiovascular vulnerability. Treatment with cinacalcet combined with low doses of vitamin D slowed the progression of CAC compared to therapy using larger, varying doses of vitamin D.
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Leach K, Wen A, Cook AE, Sexton PM, Conigrave AD, Christopoulos A. Impact of clinically relevant mutations on the pharmacoregulation and signaling bias of the calcium-sensing receptor by positive and negative allosteric modulators. Endocrinology 2013; 154:1105-16. [PMID: 23372019 DOI: 10.1210/en.2012-1887] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Cinacalcet is predominantly used to treat secondary hyperparathyroidism due to end-stage renal failure, but, more recently, its potential clinical efficacy in treating patients with loss-of-function mutations in the calcium-sensing receptor (CaSR) has been recognized. Many clinically relevant CaSR mutations are located in the heptahelical membrane spanning and extracellular loop regions of the receptor, where allosteric modulators are predicted to bind. The aim of the present study was to investigate the impact of such mutations on the pharmacoregulation of the CaSR by the positive and negative allosteric modulators, cinacalcet and NPS-2143, respectively. Both cinacalcet and NPS-2143 effectively rescued mutants whose cell surface expression was substantially impaired, suggesting that both classes of drug can stabilize a receptor conformation that is trafficked more effectively to the cell surface. In addition, functional impairments in almost all mutant CaSRs were rescued by either cinacalcet or NPS-2143 via restoration of intracellular signaling. There was a significantly greater ability of both compounds to modulate agonist-stimulated intracellular Ca(2+) mobilization than ERK1/2 phosphorylation, indicating that the allosteric modulators engender bias in agonist-stimulated CaSR signaling to different pathways. Three mutations (G(670)R, P(748)R, and L(773)R) altered the binding affinity of allosteric modulators to the CaSR, and 3 mutations (V(817)I, L(773)R, and E(767)K) altered the cooperativity between the allosteric modulator and Ca(2+)(o). These findings have important implications for the treatment of diseases associated with CaSR mutations using allosteric CaSR modulators and for analyzing the effects of mutations on the function and pharmacoregulation of the CaSR.
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Affiliation(s)
- Katie Leach
- Monash Institute of Pharmaceutical Sciences, 399 Royal Parade, Parkville, 3052, Victoria, Australia.
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Thomsen ARB, Worm J, Jacobsen SE, Stahlhut M, Latta M, Bräuner-Osborne H. Strontium is a biased agonist of the calcium-sensing receptor in rat medullary thyroid carcinoma 6-23 cells. J Pharmacol Exp Ther 2012; 343:638-49. [PMID: 22942242 PMCID: PMC11047797 DOI: 10.1124/jpet.112.197210] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2012] [Accepted: 08/30/2012] [Indexed: 09/23/2023] Open
Abstract
The calcium-sensing receptor (CaSR)-specific allosteric modulator cinacalcet has revolutionized the treatment of secondary hyperparathyroidism in patients with chronic kidney disease. However, its application is limited to patients with end-stage renal disease because of hypocalcemic side effects presumably caused by CaSR-mediated calcitonin secretion from thyroid parafollicular C-cells. These hypocalcemic side effects might be dampened by compounds that bias the signaling of CaSR, causing similar therapeutic effects as cinacalcet without stimulating calcitonin secretion. Because biased signaling of CaSR is poorly understood, the objective of the present study was to investigate biased signaling of CaSR by using rat medullary thyroid carcinoma 6-23 cells as a model of thyroid parafollicular C-cells. By doing concentration-response experiments we focused on the ability of two well known CaSR agonists, calcium and strontium, to activate six different signaling entities: G(q/11) signaling, G(i/o) signaling, G(s) signaling, extracellular signal-regulated kinases 1 and 2 (ERK1/2) signaling, intracellular calcium ([Ca(2+)](i)) mobilization, and calcitonin secretion. The experiments showed that strontium biases CaSR signaling toward ERK1/2 signaling and possibly another pathway independent of G(q/11) signaling and [Ca(2+)](i) mobilization. It is noteworthy that the potency of strontium-stimulated calcitonin secretion was elevated compared with calcium. Combining these results with experiments investigating signaling pathway components involved in calcitonin secretion, we found that the enhanced potency of strontium-mediated calcitonin secretion was caused by a different signaling pattern than that produced by calcium. Together, our results suggest that calcitonin secretion can be affected by CaSR-stimulated signaling bias, which may be used to develop novel drugs for the treatment of secondary hyperparathyroidism.
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Affiliation(s)
- Alex Rojas Bie Thomsen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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Li T, Sun M, Yin X, Wu C, Wu Q, Feng S, Li H, Luan Y, Wen J, Yan L, Zhao B, Xu C, Sun Y. Expression of the calcium sensing receptor in human peripheral blood T lymphocyte and its contribution to cytokine secretion through MAPKs or NF-κB pathways. Mol Immunol 2012; 53:414-20. [PMID: 23103379 DOI: 10.1016/j.molimm.2012.09.010] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2012] [Revised: 09/13/2012] [Accepted: 09/24/2012] [Indexed: 11/18/2022]
Abstract
The calcium-sensing receptor (CaSR) has been reported to play an important role in many tissues and organs. However, studies about the expression and function of CaSR in T lymphocytes are still not very lucid. In this study, we investigated the above-mentioned issues using RT-PCR, immunofluorescence staining, Western blotting, and the ELISA techniques. We found that the CaSR protein was expressed, and mainly located in the membrane in the normal human peripheral blood T lymphocytes. GdCl(3) (an agonist of CaSR) increased the dose-dependency of the CaSR expression, which was abolished by NPS2390 (an inhibitor of CaSR). GdCl(3) and Ca(2+) increased the phosphorylation of extracellular signal-regulated kinase (ERK)1/2 (one subgroup of MAPKs) and P65 (subunit of NF-κB),but, they had no significant effects on the JNK and P38 subgroups of MAPKs. Meantime, GdCl(3) and Ca(2+) stimulated both the IL-6 and TNF-β releases and their mRNA expressions. However, these effects of GdCl(3) and Ca(2+) were inhibited by NPS2390, U0126 (MAPKs pathway inhibitor) or Bay-11-7082 (NF-κB pathway inhibitor). These results suggested that CaSR was functionally expressed in the T cells, and the activated CaSR contributed to the cytokine secretion through the partial MAPK and NF-κB pathways.
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Affiliation(s)
- Tingting Li
- Department of Clinical Laboratory, The Second Affiliated Hospital of Harbin Medical University, Harbin 150086, China
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Cetani F, Saponaro F, Banti C, Cianferotti L, Vignali E, Chiavistelli S, Viccica G, Pinchera A, Marcocci C. Cinacalcet efficacy in patients with moderately severe primary hyperparathyroidism according to the European Medicine Agency prescription labeling. J Endocrinol Invest 2012; 35:655-60. [PMID: 21971564 DOI: 10.3275/7970] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
BACKGROUND Patients with primary hyperparathyroidism (PHPT) with contraindications to parathyroidectomy (PTx) or persistent PHPT have few non surgical options. AIM The aim of the study was to investigate the efficacy of cinacalcet in reducing serum calcium in patients with PHPT, for whom PTx would be indicated according to serum calcium levels, but in whom PTx is not clinically appropriate or is contraindicated [European Medicines Agency (EMA) prescription labeling]. SUBJECTS AND METHODS The study (open-label prospective, conducted in a single tertiary center) included 12 sporadic and 2 multiple endocrine neoplasia type 1 PHPT patients with serum calcium greater than 11.2 mg/dl. Cinacalcet was administered in increasing doses until normal serum calcium was reached or side effects preventing a further increase occurred. Serum calcium, PTH, phosphate, 25OHD, markers of bone turnover, 24h-urinary calcium and areal bone mineral density (BMD) were measured. Safety biochemical indices and adverse events were monitored. RESULTS The maintenance cinacalcet dose [median 30 mg twice daily (range 30 daily-60 mg twice daily)] was maintained constant during follow-up (median 12 months). Mean±SE baseline serum calcium was 12.2±0.3 mg/dl. Serum calcium decreased by at least 1 mg/dl in all patients and normalized in 10. Serum calcium at the last observation was 9.9±0.2 mg/dl (p<0.0001 vs baseline). PTH decreased by 17.1% compared to baseline (p=0.13), and never reached a normal value. BMD was unchanged. Adverse events occurred in 6 patients (43%) and required treatment withdrawal in 2. CONCLUSIONS Cinacalcet reduced and often normalized serum calcium in PHPT patients who met the EMA labeling.
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Affiliation(s)
- F Cetani
- Department of Endocrinology and Metabolism, Section of Endocrinology and Bone Metabolism, University of Pisa, Via Paradisa 2, 56124 Pisa, Italy
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Maruyama Y, Yasuda R, Kuroda M, Eto Y. Kokumi substances, enhancers of basic tastes, induce responses in calcium-sensing receptor expressing taste cells. PLoS One 2012; 7:e34489. [PMID: 22511946 PMCID: PMC3325276 DOI: 10.1371/journal.pone.0034489] [Citation(s) in RCA: 106] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2011] [Accepted: 03/01/2012] [Indexed: 11/19/2022] Open
Abstract
Recently, we reported that calcium-sensing receptor (CaSR) is a receptor for kokumi substances, which enhance the intensities of salty, sweet and umami tastes. Furthermore, we found that several γ-glutamyl peptides, which are CaSR agonists, are kokumi substances. In this study, we elucidated the receptor cells for kokumi substances, and their physiological properties. For this purpose, we used Calcium Green-1 loaded mouse taste cells in lingual tissue slices and confocal microscopy. Kokumi substances, applied focally around taste pores, induced an increase in the intracellular Ca(2+) concentration ([Ca(2+)](i)) in a subset of taste cells. These responses were inhibited by pretreatment with the CaSR inhibitor, NPS2143. However, the kokumi substance-induced responses did not require extracellular Ca(2+). CaSR-expressing taste cells are a different subset of cells from the T1R3-expressing umami or sweet taste receptor cells. These observations indicate that CaSR-expressing taste cells are the primary detectors of kokumi substances, and that they are an independent population from the influenced basic taste receptor cells, at least in the case of sweet and umami.
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Affiliation(s)
- Yutaka Maruyama
- Institute for Innovation, Ajinomoto Co, Inc, Kawasaki, Japan.
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Procino G, Mastrofrancesco L, Tamma G, Lasorsa DR, Ranieri M, Stringini G, Emma F, Svelto M, Valenti G. Calcium-sensing receptor and aquaporin 2 interplay in hypercalciuria-associated renal concentrating defect in humans. An in vivo and in vitro study. PLoS One 2012; 7:e33145. [PMID: 22403735 PMCID: PMC3293925 DOI: 10.1371/journal.pone.0033145] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2011] [Accepted: 02/10/2012] [Indexed: 01/08/2023] Open
Abstract
One mechanism proposed for reducing the risk of calcium renal stones is activation of the calcium-sensing receptor (CaR) on the apical membranes of collecting duct principal cells by high luminal calcium. This would reduce the abundance of aquaporin-2 (AQP2) and in turn the rate of water reabsorption. While evidence in cells and in hypercalciuric animal models supports this hypothesis, the relevance of the interplay between the CaR and AQP2 in humans is not clear. This paper reports for the first time a detailed correlation between urinary AQP2 excretion under acute vasopressin action (DDAVP treatment) in hypercalciuric subjects and in parallel analyzes AQP2-CaR crosstalk in a mouse collecting duct cell line (MCD4) expressing endogenous and functional CaR. In normocalciurics, DDAVP administration resulted in a significant increase in AQP2 excretion paralleled by an increase in urinary osmolality indicating a physiological response to DDAVP. In contrast, in hypercalciurics, baseline AQP2 excretion was high and did not significantly increase after DDAVP. Moreover DDAVP treatment was accompanied by a less pronounced increase in urinary osmolality. These data indicate reduced urinary concentrating ability in response to vasopressin in hypercalciurics. Consistent with these results, biotinylation experiments in MCD4 cells revealed that membrane AQP2 expression in unstimulated cells exposed to CaR agonists was higher than in control cells and did not increase significantly in response to short term exposure to forskolin (FK). Interestingly, we found that CaR activation by specific agonists reduced the increase in cAMP and prevented any reduction in Rho activity in response to FK, two crucial pathways for AQP2 translocation. These data support the hypothesis that CaR–AQP2 interplay represents an internal renal defense to mitigate the effects of hypercalciuria on the risk of calcium precipitation during antidiuresis. This mechanism and possibly reduced medulla tonicity may explain the lower concentrating ability observed in hypercalciuric patients.
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Affiliation(s)
- Giuseppe Procino
- Department of Biosciences, Biotechnologies and Pharmacological Sciences and Center of Excellence in Comparative Genomics, University of Bari, Bari, Italy
| | - Lisa Mastrofrancesco
- Department of Biosciences, Biotechnologies and Pharmacological Sciences and Center of Excellence in Comparative Genomics, University of Bari, Bari, Italy
| | - Grazia Tamma
- Department of Biosciences, Biotechnologies and Pharmacological Sciences and Center of Excellence in Comparative Genomics, University of Bari, Bari, Italy
| | - Domenica Rita Lasorsa
- Department of Biosciences, Biotechnologies and Pharmacological Sciences and Center of Excellence in Comparative Genomics, University of Bari, Bari, Italy
| | - Marianna Ranieri
- Department of Biosciences, Biotechnologies and Pharmacological Sciences and Center of Excellence in Comparative Genomics, University of Bari, Bari, Italy
| | | | | | - Maria Svelto
- Department of Biosciences, Biotechnologies and Pharmacological Sciences and Center of Excellence in Comparative Genomics, University of Bari, Bari, Italy
| | - Giovanna Valenti
- Department of Biosciences, Biotechnologies and Pharmacological Sciences and Center of Excellence in Comparative Genomics, University of Bari, Bari, Italy
- * E-mail:
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Thomsen ARB, Hvidtfeldt M, Bräuner-Osborne H. Biased agonism of the calcium-sensing receptor. Cell Calcium 2012; 51:107-16. [PMID: 22192592 DOI: 10.1016/j.ceca.2011.11.009] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2011] [Revised: 11/05/2011] [Accepted: 11/24/2011] [Indexed: 02/01/2023]
Abstract
After the discovery of molecules modulating G protein-coupled receptors (GPCRs) that are able to selectively affect one signaling pathway over others for a specific GPCR, thereby "biasing" the signaling, it has become obvious that the original model of GPCRs existing in either an "on" or "off" conformation is too simple. The current explanation for this biased agonism is that GPCRs can adopt multiple active conformations stabilized by different molecules, and that each conformation affects intracellular signaling in a different way. In the present study we sought to investigate biased agonism of the calcium-sensing receptor (CaSR), by looking at 12 well-known orthosteric CaSR agonists in 3 different CaSR signaling pathways: G(q/11) protein, G(i/o) protein, and extracellular signal-regulated kinases 1 and 2 (ERK1/2). Here we show that apart from G(q/11) and G(i/o) signaling, ERK1/2 is activated through recruitment of β-arrestins. Next, by measuring activity of all three signaling pathways we found that barium, spermine, neomycin, and tobramycin act as biased agonist in terms of efficacy and/or potency. Finally, polyamines and aminoglycosides in general were biased in their potencies toward ERK1/2 signaling. In conclusion, the results of this study indicate that several active conformations of CaSR, stabilized by different molecules, exist, which affect intracellular signaling distinctly.
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Affiliation(s)
- Alex Rojas Bie Thomsen
- Department of Medicinal Chemistry, Faculty of Pharmaceutical Sciences, University of Copenhagen, Fruebjergvej 3, Copenhagen, Denmark
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Geibel JP. The calcium-sensing receptor. J Nephrol 2010; 23 Suppl 16:S130-S135. [PMID: 21170870] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/01/2010] [Indexed: 05/30/2023]
Abstract
To maintain divalent ion concentration within the body, a complex sensor has evolved to identify the changes in the extracellular environment and cause the surrounding cells to either secrete or absorb in response to change. An important member of these "sensors" is the calcium-sensing receptor (CaSR), which is constantly monitoring the extracellular environment for changes in salinity, pH, calcium, amino acids and polyamines. The kidney plays a very important role in monitoring both salinity and also water concentration of the presented filtered load. Recent studies have shown that the CaSR is expressed along the nephron and can play an important role in both calcium and salt absorption, and also in the handling of water in the thick ascending limb. This review will outline the basic physiology of the receptor and will then go on to discuss some of the roles that the receptor plays in the various nephron segments. It will conclude with a brief section on future directions and how specific renal receptor-targeted drugs may provide an effective means to regulate both ionic absorption and water balance.
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Affiliation(s)
- John P Geibel
- Yale University School of Medicine, New Haven, Connecticut 06520-8026, USA.
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Uemura K, Kakuta T. [CKD-MBD (Chronic Kidney Disease-Mineral and Bone Disorder). Parathyroid interventions: final one piece in the management of uremic SHPT patients]. Clin Calcium 2010; 20:1104-1110. [PMID: 20585190] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
The term "renal osteodystrophy" has recently been replaced with "CKD-mineral and bone disorder (CKD-MBD)", which includes vascular calcification as well as bone abnormalities. Following this paradigm shift, the Japanese Society for Dialysis Therapy released guidelines for the management of secondary hyperparathyroidism in chronic dialysis patients, which prioritized improvement in survival, but not in bone abnormalities. According to these guidelines, parathyroid intervention, such as parathyroidectomy and percutaneous ethanol injection therapy, should be indicated if mineral disorders cannot be managed by pharmacological means. Recently, several novel therapeutic tools, including sevelamer hydrochloride, calcitriol analogs, and cinacalcet hydrochloride have been introduced in the clinical setting in Japan. The other side 2009 KDIGO guideline suggest that, if the intact PTH levels fall below two times the upper limit of normal for the assay, calcitriol, vitamin D analogs, and/or calcimimetics be reduced or stopped. And in patients with CKD stages 3-5D with severe hyperparathyroidism (HPT) who fail to respond to medical/pharmacological therapy, this guideline suggest parathyroidectomy. Harmonizing these therapeutic modalities and parathyroid interventions, we should expect more effective management of CKD-MBD, leading to the improvement of morbidity and mortality in this patient population. In this part, we consider indication of parathyroid interventions surround the present condition.
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Abstract
Recent progress has been made in our understanding of the functional role of the seven-transmembrane-spanning extracellular calcium-sensing receptor (CaSR) in bone cells. Both in vitro and in vivo data indicate that the CaSR is a physiological regulator of bone cell metabolism. The CaSR regulates the recruitment, differentiation and survival of osteoblasts and osteoclasts through activation of multiple CaSR-mediated intracellular signaling pathways in bone cells. This raises the possibility that the bone CaSR could potentially be targeted by allosteric modulators, either agonists (calcimimetics) or antagonists (calcilytics) to control bone remodeling. The therapeutic potential of CaSR agonists or antagonists in bone cells is however hampered by their effects on the CaSR in nonskeletal tissues. Rather, direct targeting of the bone CaSR may be of potential interest for the treatment of bone diseases. Targeting the bone CaSR using a bone-seeking CaSR agonist offers a potential mean to modulate bone cell metabolism. The development of drugs that preferentially target the CaSR and possibly other cation-sensing receptors in bone cells may thus be helpful for the treatment of osteoporosis.
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Chen W, Bergsman JB, Wang X, Gilkey G, Pierpoint CR, Daniel EA, Awumey EM, Dauban P, Dodd RH, Ruat M, Smith SM. Presynaptic external calcium signaling involves the calcium-sensing receptor in neocortical nerve terminals. PLoS One 2010; 5:e8563. [PMID: 20052292 PMCID: PMC2797309 DOI: 10.1371/journal.pone.0008563] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2009] [Accepted: 12/08/2009] [Indexed: 01/20/2023] Open
Abstract
BACKGROUND Nerve terminal invasion by an axonal spike activates voltage-gated channels, triggering calcium entry, vesicle fusion, and release of neurotransmitter. Ion channels activated at the terminal shape the presynaptic spike and so regulate the magnitude and duration of calcium entry. Consequently characterization of the functional properties of ion channels at nerve terminals is crucial to understand the regulation of transmitter release. Direct recordings from small neocortical nerve terminals have revealed that external [Ca(2+)] ([Ca(2+)](o)) indirectly regulates a non-selective cation channel (NSCC) in neocortical nerve terminals via an unknown [Ca(2+)](o) sensor. Here, we identify the first component in a presynaptic calcium signaling pathway. METHODOLOGY/PRINCIPAL FINDINGS By combining genetic and pharmacological approaches with direct patch-clamp recordings from small acutely isolated neocortical nerve terminals we identify the extracellular calcium sensor. Our results show that the calcium-sensing receptor (CaSR), a previously identified G-protein coupled receptor that is the mainstay in serum calcium homeostasis, is the extracellular calcium sensor in these acutely dissociated nerve terminals. The NSCC currents from reduced function mutant CaSR mice were less sensitive to changes in [Ca(2+)](o) than wild-type. Calindol, an allosteric CaSR agonist, reduced NSCC currents in direct terminal recordings in a dose-dependent and reversible manner. In contrast, glutamate and GABA did not affect the NSCC currents. CONCLUSIONS/SIGNIFICANCE Our experiments identify CaSR as the first component in the [Ca(2+)](o) sensor-NSCC signaling pathway in neocortical terminals. Decreases in [Ca(2+)](o) will depress synaptic transmission because of the exquisite sensitivity of transmitter release to [Ca(2+)](o) following its entry via voltage-activated Ca(2+) channels. CaSR may detects such falls in [Ca(2+)](o) and increase action potential duration by increasing NSCC activity, thereby attenuating the impact of decreases in [Ca(2+)](o) on release probability. CaSR is positioned to detect the dynamic changes of [Ca(2+)](o) and provide presynaptic feedback that will alter brain excitability.
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Affiliation(s)
- Wenyan Chen
- Division of Pulmonary & Critical Care Medicine, Oregon Health & Science University, Portland, Oregon, United States of America
| | - Jeremy B. Bergsman
- Division of Pulmonary & Critical Care Medicine, Oregon Health & Science University, Portland, Oregon, United States of America
| | - Xiaohua Wang
- Division of Pulmonary & Critical Care Medicine, Oregon Health & Science University, Portland, Oregon, United States of America
| | - Gawain Gilkey
- Division of Pulmonary & Critical Care Medicine, Oregon Health & Science University, Portland, Oregon, United States of America
| | - Carol-Renée Pierpoint
- Division of Pulmonary & Critical Care Medicine, Oregon Health & Science University, Portland, Oregon, United States of America
| | - Erin A. Daniel
- Division of Pulmonary & Critical Care Medicine, Oregon Health & Science University, Portland, Oregon, United States of America
| | - Emmanuel M. Awumey
- Julius L. Chambers Biomedical/Biotechnology Research Institute, North Carolina Central University, Durham, North Carolina, United States of America
| | - Philippe Dauban
- Centre National de la Recherche Scientifique, Institut de Chimie des Substances Naturelles, Gif-sur-Yvette, France
| | - Robert H. Dodd
- Centre National de la Recherche Scientifique, Institut de Chimie des Substances Naturelles, Gif-sur-Yvette, France
| | - Martial Ruat
- Centre National de la Recherche Scientifique, Institut de Neurobiologie Alfred Fessard, Gif-sur-Yvette, France
| | - Stephen M. Smith
- Division of Pulmonary & Critical Care Medicine, Oregon Health & Science University, Portland, Oregon, United States of America
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Minagawa M. [Clinical aspect of recent progress in phosphate metabolism. Treatment of hypophophatemia]. Clin Calcium 2009; 19:852-855. [PMID: 19483281] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Most hypophosphatemic patients will not require immediate replacement therapy with phosphate. In only the patients with acute severe hypophosphatemia (<1 mg/dL) or symptoms, intravenous phosphate replacement therapy is indicated. On the other hand, the patients with chronic hypophosphatemia require the medical treatment with oral administration of calcitriol and neutral phosphate since this condition causes hypophosphatemic rickets/osteomalacia. However, the treatment regimen has not been standardized, and nephrocalcinosis and tertially hyperparathyroidism are the complication of the long-term treatment. Adjuvant therapy with calcimimetics or suppression therapy for FGF23 action may improve long-term outcome.
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Affiliation(s)
- Masanori Minagawa
- Department of Pediatrics, Graduate School of Medicine, Chiba University
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Nguyen TV, Filson J. Caring for chronic kidney disease patients: focus on mineral and bone disorders. Consult Pharm 2009; 24:146-152. [PMID: 19275456 DOI: 10.4140/tcp.n.2009.146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
This case study focuses on a patient with chronic kidney disease (CKD) with mineral and bone disorders (MBD) and the relationship and management strategies used in treating CKD-MBD. The various risks and issues pertaining to the CKD stage 5 patient population are addressed, including CKD-MBD and renal osteodystrophy. Proper management of CKD-MBD with diet, dialysis, laboratory testing, and medications is discussed. An interdisciplinary team that includes the patient and family is crucial for effective management of MBD.
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Affiliation(s)
- Timothy V Nguyen
- Nephrology and Dialysis, Holy Name Hospital, Department of Pharmacy, Teaneck, NJ 07666, USA.
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Akizawa T. 19th Annual Meeting of the Japanese Society for Kidney Bone Disease. Ther Apher Dial 2008; 12 Suppl 1:S1. [PMID: 19032519 DOI: 10.1111/j.1744-9987.2008.00632.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Lomonte C, Vernaglione L, Chimienti D, Bruno A, Cocola S, Teutonico A, Cazzato F, Basile C. Does vitamin D receptor and calcium receptor activation therapy play a role in the histopathologic alterations of parathyroid glands in refractory uremic hyperparathyroidism? Clin J Am Soc Nephrol 2008; 3:794-9. [PMID: 18322048 PMCID: PMC2386693 DOI: 10.2215/cjn.04150907] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2007] [Accepted: 01/10/2008] [Indexed: 11/23/2022]
Abstract
BACKGROUND AND OBJECTIVES Vitamin D receptor activation by vitamin D sterols and calcium-sensing receptor stimulation by cinacalcet are the most powerful treatments of secondary hyperparathyroidism. This study was aimed to assess a possible association between histopathologic changes of parathyroid tissue and treatment modality. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS Studies were performed on 82 parathyroids of 22 adult white hemodialysis patients undergoing first parathyroidectomy. The type of hyperplasia and the distribution of chief and oxyphil cells, expressed as oxyphil/chief cell ratio, were assessed. Three groups could be studied according to treatment modality: group A consisted of 6 patients who were treated with cinacalcet, intravenous calcitriol, and phosphate binders; group B consisted of 6 patients who were treated with intravenous calcitriol and phosphate binders, and group C consisted of 10 patients who were treated with phosphate binders alone. RESULTS Sixty-eight (82.9%) out of 82 glands removed showed nodular hyperplasia. It was more frequent in groups A and B than in group C. A stepwise forward logistic regression model showed that the probability of nodular hyperplasia was higher in patients who were on calcitriol and/or cinacalcet therapy, in female gender and in patients with a higher body mass index. Oxyphil/chief cell ratio also was significantly different among the three groups. Cinacalcet treatment was the only predictor of this ratio. CONCLUSIONS An association was found between calcitriol and/or cinacalcet therapy and a high prevalence of nodular hyperplasia, and between cinacalcet therapy and high oxyphil/chief cell ratio. The meaning of the observed associations remains uncertain.
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Affiliation(s)
- Carlo Lomonte
- Division of Nephrology, Miulli General Hospital, Acquaviva delle Fonti, Manduria, Italy
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Locatelli F, Limardo M, Pontoriero G. New approaches to treatment of secondary hyperparathyroidism. Curr Opin Investig Drugs 2008; 9:363-370. [PMID: 18393103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
A large number of patients with chronic kidney disease are affected by secondary hyperparathyroidism. The related mineral metabolism abnormalities are associated with an increased relative risk of morbidity and mortality. The management of secondary hyperparathyroidism is made more complex by the fact that the disease progresses over time. Recent approaches to its management include vitamin D analogs, non-calcium/non-aluminum containing phosphate binders and calcimimetics.
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Affiliation(s)
- Francesco Locatelli
- Department of Nephrology, Dialysis and Renal Transplantation, A Manzoni Hospital, Lecco, Italy.
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