1
|
Nanoff C, Yang Q, Hellinger R, Hermann M. Activation of the Calcium-Sensing Receptor by a Subfraction of Amino Acids Contained in Thyroid Drainage Fluid. ACS Pharmacol Transl Sci 2024; 7:1937-1950. [PMID: 39022353 PMCID: PMC11249632 DOI: 10.1021/acsptsci.3c00350] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Revised: 06/03/2024] [Accepted: 06/17/2024] [Indexed: 07/20/2024]
Abstract
Hypoparathyroidism is a common sequela of thyroid surgery; in this study, we aimed at exploring the pathogenesis behind it. The following premises suggest that wound fluid might be a causative agent. (i) Parathyroid hormone secretion is under feedback control by the calcium-sensing receptor, which responds to a diverse array of activating ligands. (ii) Postoperative hypoparathyroidism arises from a secretory deficiency of the parathyroid glands. Even in patients later unaffected by hypoparathyroidism, parathyroid hormone levels drop within hours after surgery. (iii) Wound fluid is bound to enter the tissue around the thyroid bed, where the parathyroid glands are located. Its composition is shaped by a series of proteolytic reactions triggered by wounding. Using thyroid drainage as a surrogate, we addressed the possibility that wound fluid contains compounds activating the calcium-sensing receptor. Drainage fluid ultrafiltrate was found to be rich in amino acids, and on separation by HPLC, compounds activating the calcium-sensing receptor partitioned with hydrophilic matter that rendered buffer acidic. The data show that glutamate and aspartate at millimolar concentrations supported activation of the calcium-sensing receptor, an effect contingent on low pH. In the presence of glutamate/aspartate, protons activated the calcium-sensing receptor with a pH50 of 6.1, and at pH 5, produced maximal activation. This synergistic mode of action was exclusive; glutamine/asparagine did not substitute for the acidic amino acids, nor did Ca2+ substitute for protons. NPS-2143, a negative allosteric receptor modulator completely blocked receptor activation by glutamate/aspartate and by fractionated drainage fluid. Thus, wound fluid may be involved in suppressing parathyroid hormone secretion.
Collapse
Affiliation(s)
- Christian Nanoff
- Centre
for Physiology and Pharmacology, Gaston H. Glock Laboratories for
Exploratory Drug Research, Medizinische
Universität Wien, Währinger Straße 13A, Vienna 1090, Austria
| | - Qiong Yang
- Centre
for Physiology and Pharmacology, Gaston H. Glock Laboratories for
Exploratory Drug Research, Medizinische
Universität Wien, Währinger Straße 13A, Vienna 1090, Austria
| | - Roland Hellinger
- Centre
for Physiology and Pharmacology, Gaston H. Glock Laboratories for
Exploratory Drug Research, Medizinische
Universität Wien, Währinger Straße 13A, Vienna 1090, Austria
| | - Michael Hermann
- Department
of Surgery, Vienna Hospital Association,
Klinik Landstraße, Juchgasse 25, Vienna 1030, Austria
| |
Collapse
|
2
|
Bränström R, Vukojević V, Lu M, Shabo I, Mun HC, Conigrave AD, Farnebo LO, Larsson C. Ca 2+-activated K + channels modulate membrane potential in the human parathyroid cell: Possible role in exocytosis. Exp Cell Res 2023; 433:113858. [PMID: 37995920 DOI: 10.1016/j.yexcr.2023.113858] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2023] [Revised: 11/12/2023] [Accepted: 11/17/2023] [Indexed: 11/25/2023]
Abstract
The relationships between parathyroid hormone (PTH) secretion and parathyroid cell membrane potential, including the identities and roles of K+ channels that regulate and/or modulate membrane potential are not well defined. Here we have used Western blot/immunohistochemistry as well as patch-clamp and perifusion techniques to identify and localize specific K+ channels in parathyroid cells and to investigate their roles in the control of membrane potential and PTH secretion. We also re-investigated the relationship between membrane potential and exocytosis. We showed that in single human parathyroid cells K+ current is dependent on at least two types of Ca2+-activated K+ channels: a small-conductance Ca2+-activated K+ channel (KSK) and a large-conductance voltage and Ca2+-activated K+ channel (KBK). These channels were sensitive to specific peptide blocking toxins including apamin, charybdotoxin, and iberiotoxin. These channels confer sensitivity of the membrane potential in single cells to high extracellular K+, TEA, and peptide toxins. Blocking of KBK potently inhibited K+ channel current, and KBK was shown to be expressed in the plasma membrane of parathyroid cells. In addition, when using the capacitance technique as an indicator of exocytosis, clamping the parathyroid cell at -60 mV prevented exocytosis, whereas holding the membrane potential at 0 mV facilitated it. Taken together, the results show that human parathyroid cells have functional KBK and KSK channels but the data presented herein suggest that KBK/KSK channels likely contribute to the maintenance of the membrane potential, and that membrane potential, per se, modulates exocytosis independently of [Ca2+]i.
Collapse
Affiliation(s)
- Robert Bränström
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden.
| | - Vladana Vukojević
- Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Ming Lu
- Department of Oncology-Pathology, Karolinska Institutet, Stockholm, Sweden
| | - Ivan Shabo
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
| | - Hee-Chang Mun
- School of Molecular and Microbial Biosciences, University of Sydney, Sydney, NSW, Australia
| | - Arthur D Conigrave
- School of Molecular and Microbial Biosciences, University of Sydney, Sydney, NSW, Australia
| | - Lars-Ove Farnebo
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
| | - Catharina Larsson
- Department of Oncology-Pathology, Karolinska Institutet, Stockholm, Sweden
| |
Collapse
|
3
|
Dowsett L, Duluc L, Higgins E, Alghamdi F, Fast W, Salt IP, Leiper J. Asymmetric dimethylarginine positively modulates calcium-sensing receptor signalling to promote lipid accumulation. Cell Signal 2023; 107:110676. [PMID: 37028778 DOI: 10.1016/j.cellsig.2023.110676] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Revised: 03/10/2023] [Accepted: 04/03/2023] [Indexed: 04/08/2023]
Abstract
Asymmetric dimethylarginine (ADMA) is generated through the irreversible methylation of arginine residues. It is an independent risk factor for cardiovascular disease, currently thought to be due to its ability to act as a competitive inhibitor of the nitric oxide (NO) synthase enzymes. Plasma ADMA concentrations increase with obesity and fall following weight loss; however, it is unknown whether they play an active role in adipose pathology. Here, we demonstrate that ADMA drives lipid accumulation through a newly identified NO-independent pathway via the amino-acid sensitive calcium-sensing receptor (CaSR). ADMA treatment of 3 T3-L1 and HepG2 cells upregulates a suite of lipogenic genes with an associated increase in triglyceride content. Pharmacological activation of CaSR mimics ADMA while negative modulation of CaSR inhibits ADMA driven lipid accumulation. Further investigation using CaSR overexpressing HEK293 cells demonstrated that ADMA potentiates CaSR signalling via Gq intracellular Ca2+ mobilisation. This study identifies a signalling mechanism for ADMA as an endogenous ligand of the G protein-coupled receptor CaSR that potentially contributes to the impact of ADMA in cardiometabolic disease.
Collapse
Affiliation(s)
- Laura Dowsett
- School of Cardiovascular and Metabolic Health, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK; MRC London Institute of Medical Sciences, Imperial College London, London W12 0NN, UK.
| | - Lucie Duluc
- MRC London Institute of Medical Sciences, Imperial College London, London W12 0NN, UK
| | - Erin Higgins
- School of Cardiovascular and Metabolic Health, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK
| | - Fatmah Alghamdi
- School of Cardiovascular and Metabolic Health, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK
| | - Walter Fast
- Division of Chemical Biology and Medicinal Chemistry, University of Texas, Austin, TX 78712, USA
| | - Ian P Salt
- School of Cardiovascular and Metabolic Health, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK; School of Molecular Biosciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK
| | - James Leiper
- School of Cardiovascular and Metabolic Health, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK; MRC London Institute of Medical Sciences, Imperial College London, London W12 0NN, UK
| |
Collapse
|
4
|
Brennan SC, Mun HC, Delbridge L, Kuchel PW, Conigrave AD. Temperature sensing by the calcium-sensing receptor. Front Physiol 2023; 14:1117352. [PMID: 36818436 PMCID: PMC9931745 DOI: 10.3389/fphys.2023.1117352] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Accepted: 01/16/2023] [Indexed: 02/05/2023] Open
Abstract
Whether GPCRs support the sensing of temperature as well as other chemical and physical modalities is not well understood. Introduction: Extracellular Ca2+ concentration (Ca2+ o) modulates core body temperature and the firing rates of temperature-sensitive CNS neurons, and hypocalcemia provokes childhood seizures. However, it is not known whether these phenomena are mediated by Ca2+ o-sensing GPCRs, including the calcium-sensing receptor (CaSR). In favor of the hypothesis, CaSRs are expressed in hypothalamic regions that support core temperature regulation, and autosomal dominant hypocalcemia, due to CaSR activating mutations, is associated with childhood seizures. Methods: Herein, we tested whether CaSR-dependent signaling is temperature sensitive using an established model system, CaSR-expressing HEK-293 cells. Results: We found that the frequency of Ca2+ o-induced Ca2+ i oscillations but not the integrated response was linearly dependent on temperature in a pathophysiologically relevant range. Chimeric receptor analysis showed that the receptor's C-terminus is required for temperature-dependent modulation and experiments with the PKC inhibitor GF109203X and CaSR mutants T888A and T888M, which eliminate a key phosphorylation site, demonstrated the importance of repetitive phosphorylation and dephosphorylation. Discussion and Conclusion: CaSRs mediate temperature-sensing and the mechanism, dependent upon repetitive phosphorylation and dephosphorylation, suggests that GPCRs more generally contribute to temperature-sensing.
Collapse
Affiliation(s)
- Sarah C. Brennan
- School of Life and Environmental Sciences, Faculty of Science, The University of Sydney, Sydney, NSW, Australia,Charles Perkins Centre, University of Sydney, Sydney, NSW, Australia
| | - Hee-chang Mun
- Charles Perkins Centre, University of Sydney, Sydney, NSW, Australia
| | - Leigh Delbridge
- Department of Surgery, Mater Hospital, North Sydney, NSW, Australia
| | - Philip W. Kuchel
- School of Life and Environmental Sciences, Faculty of Science, The University of Sydney, Sydney, NSW, Australia
| | - Arthur D. Conigrave
- School of Life and Environmental Sciences, Faculty of Science, The University of Sydney, Sydney, NSW, Australia,Charles Perkins Centre, University of Sydney, Sydney, NSW, Australia,*Correspondence: Arthur D. Conigrave,
| |
Collapse
|
5
|
Gong Y, Yang B, Zhang D, Zhang Y, Tang Z, Yang L, Coate KC, Yin L, Covington BA, Patel RS, Siv WA, Sellick K, Shou M, Chang W, Danielle Dean E, Powers AC, Chen W. Hyperaminoacidemia induces pancreatic α cell proliferation via synergism between the mTORC1 and CaSR-Gq signaling pathways. Nat Commun 2023; 14:235. [PMID: 36646689 PMCID: PMC9842633 DOI: 10.1038/s41467-022-35705-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Accepted: 12/20/2022] [Indexed: 01/18/2023] Open
Abstract
Glucagon has emerged as a key regulator of extracellular amino acid (AA) homeostasis. Insufficient glucagon signaling results in hyperaminoacidemia, which drives adaptive proliferation of glucagon-producing α cells. Aside from mammalian target of rapamycin complex 1 (mTORC1), the role of other AA sensors in α cell proliferation has not been described. Here, using both genders of mouse islets and glucagon receptor (gcgr)-deficient zebrafish (Danio rerio), we show α cell proliferation requires activation of the extracellular signal-regulated protein kinase (ERK1/2) by the AA-sensitive calcium sensing receptor (CaSR). Inactivation of CaSR dampened α cell proliferation, which was rescued by re-expression of CaSR or activation of Gq, but not Gi, signaling in α cells. CaSR was also unexpectedly necessary for mTORC1 activation in α cells. Furthermore, coactivation of Gq and mTORC1 induced α cell proliferation independent of hyperaminoacidemia. These results reveal another AA-sensitive mediator and identify pathways necessary and sufficient for hyperaminoacidemia-induced α cell proliferation.
Collapse
Affiliation(s)
- Yulong Gong
- Department of Molecular Physiology & Biophysics, Vanderbilt University, 2215 Garland Ave, Nashville, TN, 37232, USA
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei, 430072, China
| | - Bingyuan Yang
- Department of Molecular Physiology & Biophysics, Vanderbilt University, 2215 Garland Ave, Nashville, TN, 37232, USA
| | - Dingdong Zhang
- Department of Molecular Physiology & Biophysics, Vanderbilt University, 2215 Garland Ave, Nashville, TN, 37232, USA
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, 210095, China
| | - Yue Zhang
- Department of Molecular Physiology & Biophysics, Vanderbilt University, 2215 Garland Ave, Nashville, TN, 37232, USA
| | - Zihan Tang
- Department of Molecular Physiology & Biophysics, Vanderbilt University, 2215 Garland Ave, Nashville, TN, 37232, USA
| | - Liu Yang
- Department of Molecular Physiology & Biophysics, Vanderbilt University, 2215 Garland Ave, Nashville, TN, 37232, USA
| | - Katie C Coate
- Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Vanderbilt University Medical Center, 2215 Garland Ave, Nashville, TN, 37232, USA
| | - Linlin Yin
- Department of Molecular Physiology & Biophysics, Vanderbilt University, 2215 Garland Ave, Nashville, TN, 37232, USA
| | - Brittney A Covington
- Department of Molecular Physiology & Biophysics, Vanderbilt University, 2215 Garland Ave, Nashville, TN, 37232, USA
| | - Ravi S Patel
- Department of Molecular Physiology & Biophysics, Vanderbilt University, 2215 Garland Ave, Nashville, TN, 37232, USA
| | - Walter A Siv
- Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Vanderbilt University Medical Center, 2215 Garland Ave, Nashville, TN, 37232, USA
| | - Katelyn Sellick
- Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Vanderbilt University Medical Center, 2215 Garland Ave, Nashville, TN, 37232, USA
| | - Matthew Shou
- Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Vanderbilt University Medical Center, 2215 Garland Ave, Nashville, TN, 37232, USA
| | - Wenhan Chang
- University of California San Francisco and San Francisco VA Medical Center, San Francisco, CA, 94158, USA
| | - E Danielle Dean
- Department of Molecular Physiology & Biophysics, Vanderbilt University, 2215 Garland Ave, Nashville, TN, 37232, USA
- Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Vanderbilt University Medical Center, 2215 Garland Ave, Nashville, TN, 37232, USA
| | - Alvin C Powers
- Department of Molecular Physiology & Biophysics, Vanderbilt University, 2215 Garland Ave, Nashville, TN, 37232, USA
- Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Vanderbilt University Medical Center, 2215 Garland Ave, Nashville, TN, 37232, USA
- VA Tennessee Valley Healthcare System, Nashville, TN, 37212, USA
| | - Wenbiao Chen
- Department of Molecular Physiology & Biophysics, Vanderbilt University, 2215 Garland Ave, Nashville, TN, 37232, USA.
| |
Collapse
|
6
|
Podgórska B, Wielogórska-Partyka M, Godzień J, Siemińska J, Ciborowski M, Szelachowska M, Krętowski A, Siewko K. Applications of Metabolomics in Calcium Metabolism Disorders in Humans. Int J Mol Sci 2022; 23:ijms231810407. [PMID: 36142318 PMCID: PMC9499180 DOI: 10.3390/ijms231810407] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Revised: 08/26/2022] [Accepted: 09/05/2022] [Indexed: 12/13/2022] Open
Abstract
The pathogenesis of the disorders of calcium metabolism is not fully understood. This review discusses the studies in which metabolomics was applied in this area. Indeed, metabolomics could play an essential role in discovering biomarkers and elucidating pathological mechanisms. Despite the limited bibliography, the present review highlights the potential of metabolomics in identifying the biomarkers of some of the most common endocrine disorders, such as primary hyperparathyroidism (PHPT), secondary hyperparathyroidism (SHPT), calcium deficiency, osteoporosis and vitamin D supplementation. Metabolites related to above-mentioned diseorders were grouped into specific classes and mapped into metabolic pathways. Furthermore, disturbed metabolic pathways can open up new directions for the in-depth exploration of the basic mechanisms of these diseases at the molecular level.
Collapse
Affiliation(s)
- Beata Podgórska
- Department of Endocrinology, Diabetology and Internal Medicine, Medical University of Bialystok, 15-276 Bialystok, Poland
- Correspondence: ; Tel.: +48-85-831-83-12
| | - Marta Wielogórska-Partyka
- Department of Endocrinology, Diabetology and Internal Medicine, Medical University of Bialystok, 15-276 Bialystok, Poland
| | - Joanna Godzień
- Clinical Research Centre, Medical University of Bialystok, 15-276 Bialystok, Poland
| | - Julia Siemińska
- Clinical Research Centre, Medical University of Bialystok, 15-276 Bialystok, Poland
| | - Michał Ciborowski
- Clinical Research Centre, Medical University of Bialystok, 15-276 Bialystok, Poland
| | - Małgorzata Szelachowska
- Department of Endocrinology, Diabetology and Internal Medicine, Medical University of Bialystok, 15-276 Bialystok, Poland
| | - Adam Krętowski
- Department of Endocrinology, Diabetology and Internal Medicine, Medical University of Bialystok, 15-276 Bialystok, Poland
- Clinical Research Centre, Medical University of Bialystok, 15-276 Bialystok, Poland
| | - Katarzyna Siewko
- Department of Endocrinology, Diabetology and Internal Medicine, Medical University of Bialystok, 15-276 Bialystok, Poland
| |
Collapse
|
7
|
Sato H, Murakami S, Horii Y, Nishimura G, Iwai R, Goto M, Takahashi N. Upacicalcet is a novel secondary hyperparathyroidism drug that targets the amino acid binding site of calcium-sensing receptor. Mol Pharmacol 2022; 102:183-195. [DOI: 10.1124/molpharm.122.000522] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Accepted: 07/14/2022] [Indexed: 11/22/2022] Open
|
8
|
Duanmu Q, Tan B, Wang J, Huang B, Li J, Kang M, Huang K, Deng Q, Yin Y. The Amino Acids Sensing and Utilization in Response to Dietary Aromatic Amino Acid Supplementation in LPS-Induced Inflammation Piglet Model. Front Nutr 2022; 8:819835. [PMID: 35111801 PMCID: PMC8801454 DOI: 10.3389/fnut.2021.819835] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Accepted: 12/16/2021] [Indexed: 12/19/2022] Open
Abstract
Dietary supplementation with aromatic amino acids (AAAs) has been demonstrated to alleviate intestinal inflammation induced by lipopolysaccharide (LPS) in the piglets. But the mechanism of AAA sensing and utilization under inflammatory conditions is not well-understood. The study was conducted with 32 weanling piglets using a 2 × 2 factorial arrangement (diet and LPS challenge) in a randomized complete block design. Piglets were fed as basal diet or the basal diet supplemented with 0.16% tryptophan (Trp), 0.41% phenylalanine (Phe), and 0.22% tyrosine (Tyr) for 21 days. The results showed that LPS treatment significantly reduced the concentrations of cholecystokinin (CCK) and total protein but increased leptin concentration, the activities of alanine transaminase, and aspartate aminotransferase in serum. Dietary supplementation with AAAs significantly increased the serum concentrations of CCK, peptide YY (PYY), and total protein but decreased the blood urea nitrogen. LPS challenge reduced the ileal threonine (Thr) digestibility, as well as serum isoleucine (Ile) and Trp concentrations, but increased the serum concentrations of Phe, Thr, histidine (His), alanine (Ala), cysteine (Cys), and serine (Ser) (P < 0.05). The serum-free amino acid concentrations of His, lysine (Lys), arginine (Arg), Trp, Tyr, Cys, and the digestibilities of His, Lys, Arg, and Cys were significantly increased by feeding AAA diets (P < 0.05). Dietary AAA supplementation significantly increased the serum concentrations of Trp in LPS-challenged piglets (P < 0.05). In the jejunal mucosa, LPS increased the contents of Ala and Cys, and the mRNA expressions of solute carrier (SLC) transporters (i.e., SLC7A11, SLC16A10, SLC38A2, and SLC3A2), but decreased Lys and glutamine (Gln) contents, and SLC1A1 mRNA expression (P < 0.05). In the ileal mucosa, LPS challenge induced increasing in SLC7A11 and SLC38A2 and decreasing in SLC38A9 and SLC36A1 mRNA expressions, AAAs supplementation significantly decreased mucosal amino acid (AA) concentrations of methionine (Met), Arg, Ala, and Tyr, etc. (P < 0.05). And the interaction between AAAs supplementation and LPS challenge significantly altered the expressions of SLC36A1 and SLC38A9 mRNA (P < 0.05). Together, these findings indicated that AAAs supplementation promoted the AAs absorption and utilization in the small intestine of piglets and increased the mRNA expressions of SLC transports to meet the high demands for specific AAs in response to inflammation and immune response.
Collapse
Affiliation(s)
- Qing Duanmu
- College of Animal Science and Technology, Hunan Agricultural University, Changsha, China
| | - Bie Tan
- College of Animal Science and Technology, Hunan Agricultural University, Changsha, China
- Laboratory of Animal Nutritional Physiology and Metabolic Process, Key Laboratory of Agro-Ecological Processes in Subtropical Region, National Engineering Laboratory for Pollution Control and Waste Utilization in Livestock and Poultry Production, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, China
| | - Jing Wang
- College of Animal Science and Technology, Hunan Agricultural University, Changsha, China
| | - Bo Huang
- College of Animal Science and Technology, Hunan Agricultural University, Changsha, China
- Laboratory of Animal Nutritional Physiology and Metabolic Process, Key Laboratory of Agro-Ecological Processes in Subtropical Region, National Engineering Laboratory for Pollution Control and Waste Utilization in Livestock and Poultry Production, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, China
| | - Jianjun Li
- Laboratory of Animal Nutritional Physiology and Metabolic Process, Key Laboratory of Agro-Ecological Processes in Subtropical Region, National Engineering Laboratory for Pollution Control and Waste Utilization in Livestock and Poultry Production, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, China
| | - Meng Kang
- College of Animal Science and Technology, Hunan Agricultural University, Changsha, China
| | - Ke Huang
- College of Animal Science and Technology, Hunan Agricultural University, Changsha, China
| | - Qiuchun Deng
- College of Animal Science and Technology, Hunan Agricultural University, Changsha, China
| | - Yulong Yin
- College of Animal Science and Technology, Hunan Agricultural University, Changsha, China
- Laboratory of Animal Nutritional Physiology and Metabolic Process, Key Laboratory of Agro-Ecological Processes in Subtropical Region, National Engineering Laboratory for Pollution Control and Waste Utilization in Livestock and Poultry Production, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, China
| |
Collapse
|
9
|
Lee JJ, Alzamil J, Rehman S, Pan W, Dimke H, Alexander RT. Activation of the calcium sensing receptor increases claudin-14 expression via a PLC -p38-Sp1 pathway. FASEB J 2021; 35:e21982. [PMID: 34694654 PMCID: PMC9297942 DOI: 10.1096/fj.202002137rrr] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Revised: 09/22/2021] [Accepted: 09/24/2021] [Indexed: 11/13/2022]
Abstract
Activation of the basolateral calcium sensing receptor (CaSR) in the renal tubular thick ascending limb (TAL) increases claudin‐14 expression, which reduces paracellular calcium (Ca2+) permeability, thus increasing urinary Ca2+ excretion. However, the upstream signaling pathway contributing to altered CLDN14 gene expression is unknown. To delineate this pathway, we identified and then cloned the CaSR responsive region including the promoter of mouse Cldn14 into a luciferase reporter vector. This 1500 bp sequence upstream of the 5′ UTR of Cldn14 variant 1, conferred increased reporter activity in the presence of high extracellular Ca2+ (5 mM) relative to a lower (0.5 mM) concentration. Assessment of Cldn14 reporter activity in response to increased extracellular Ca2+ in the presence or absence of specific inhibitors confirmed signaling through PLC and p38, but not JNK. Overexpression of SP1 attenuated Cldn14 reporter activity in response to CasR signaling. SP1 is expressed in the TAL and phosphorylation was attenuated by CaSR signaling. Finally, activating mutations in the CaSR increased Cldn14 reporter activity while a dominant negative mutation in the CaSR inhibited it. Together, these studies suggest that basolateral activation of the CASR leads to increased Cldn14 expression via a PLC‐ stimulated p38 pathway that prevents Sp1 mediated repression.
Collapse
Affiliation(s)
- Justin J Lee
- Department of Physiology, University of Alberta, Edmonton, Alberta, Canada.,The Women's & Children's Health Research Institute, Edmonton, Alberta, Canada
| | - Jawad Alzamil
- Department of Physiology, University of Alberta, Edmonton, Alberta, Canada
| | - Saba Rehman
- Department of Physiology, University of Alberta, Edmonton, Alberta, Canada
| | - Wanling Pan
- Department of Physiology, University of Alberta, Edmonton, Alberta, Canada
| | - Henrik Dimke
- Department of Cardiovascular and Renal Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark.,Department of Nephrology, Odense University Hospital, Odense, Denmark
| | - R Todd Alexander
- Department of Physiology, University of Alberta, Edmonton, Alberta, Canada.,The Women's & Children's Health Research Institute, Edmonton, Alberta, Canada.,Department of Pediatrics, University of Alberta, Edmonton, Alberta, Canada
| |
Collapse
|
10
|
Chen X, Wang L, Cui Q, Ding Z, Han L, Kou Y, Zhang W, Wang H, Jia X, Dai M, Shi Z, Li Y, Li X, Geng Y. Structural insights into the activation of human calcium-sensing receptor. eLife 2021; 10:68578. [PMID: 34467854 PMCID: PMC8476121 DOI: 10.7554/elife.68578] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Accepted: 08/31/2021] [Indexed: 12/16/2022] Open
Abstract
Human calcium-sensing receptor (CaSR) is a G-protein-coupled receptor that maintains Ca2+ homeostasis in serum. Here, we present the cryo-electron microscopy structures of the CaSR in the inactive and agonist+PAM bound states. Complemented with previously reported structures of CaSR, we show that in addition to the full inactive and active states, there are multiple intermediate states during the activation of CaSR. We used a negative allosteric nanobody to stabilize the CaSR in the fully inactive state and found a new binding site for Ca2+ ion that acts as a composite agonist with L-amino acid to stabilize the closure of active Venus flytraps. Our data show that agonist binding leads to compaction of the dimer, proximity of the cysteine-rich domains, large-scale transitions of seven-transmembrane domains, and inter- and intrasubunit conformational changes of seven-transmembrane domains to accommodate downstream transducers. Our results reveal the structural basis for activation mechanisms of CaSR and clarify the mode of action of Ca2+ ions and L-amino acid leading to the activation of the receptor.
Collapse
Affiliation(s)
- Xiaochen Chen
- The CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Lu Wang
- The CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Qianqian Cui
- The CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Zhanyu Ding
- The CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Li Han
- The CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Yongjun Kou
- The CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Wenqing Zhang
- The CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Haonan Wang
- The CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Xiaomin Jia
- The CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Mei Dai
- The CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Zhenzhong Shi
- The CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Yuying Li
- The CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Xiyang Li
- The CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Yong Geng
- The CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
| |
Collapse
|
11
|
Abid HA, Inoue A, Gorvin CM. Heterogeneity of G protein activation by the calcium-sensing receptor. J Mol Endocrinol 2021; 67:41-53. [PMID: 34077389 PMCID: PMC8240730 DOI: 10.1530/jme-21-0058] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Accepted: 06/02/2021] [Indexed: 12/20/2022]
Abstract
The calcium-sensing receptor (CaSR) is a G protein-coupled receptor that plays a fundamental role in extracellular calcium (Ca2+e) homeostasis by regulating parathyroid hormone release and urinary calcium excretion. The CaSR has been described to activate all four G protein subfamilies (Gαq/11, Gαi/o, Gα12/13, Gαs), and mutations in the receptor that cause hyper/hypocalcaemia, have been described to bias receptor signalling. However, many of these studies are based on measurements of second messengers or gene transcription that occurs many steps downstream of receptor activation and can represent convergence points of several signalling pathways. Therefore, to assess CaSR-mediated G protein activation directly, we took advantage of a recently described NanoBiT G protein dissociation assay system. Our studies, performed in HEK293 cells stably expressing CaSR, demonstrate that Ca2+e stimulation activates all Gαq/11 family and several Gαi/o family proteins, although Gαz was not activated. CaSR stimulated dissociation of Gα12/13 and Gαs from Gβ-subunits, but this occurred at a slower rate than that of other Gα-subunits. Investigation of cDNA expression of G proteins in three tissues abundantly expressing CaSR, the parathyroids, kidneys and pancreas, showed Gα11, Gαz, Gαi1 and Gα13 genes were highly expressed in parathyroid tissue, indicating CaSR most likely activates Gα11 and Gαi1 in parathyroids. In kidney and pancreas, the majority of G proteins were similarly expressed, suggesting CaSR may activate multiple G proteins in these cells. Thus, these studies validate a single assay system that can be used to robustly assess CaSR variants and biased signalling and could be utilised in the development of new pharmacological compounds targeting CaSR.
Collapse
Affiliation(s)
- Hasnat Ali Abid
- Institute of Metabolism and Systems Research and Centre for Endocrinology, Diabetes and Metabolism, University of Birmingham, Birmingham, UK
| | - Asuka Inoue
- Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Miyagi, Japan
| | - Caroline M Gorvin
- Institute of Metabolism and Systems Research and Centre for Endocrinology, Diabetes and Metabolism, University of Birmingham, Birmingham, UK
- Centre of Membrane Proteins and Receptors (COMPARE), Universities of Birmingham and Nottingham, UK
- Correspondence should be addressed to C M Gorvin:
| |
Collapse
|
12
|
Salinity-dependent expression of calcium-sensing receptors in Atlantic salmon (Salmo salar) tissues. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2021; 207:505-522. [PMID: 34114081 DOI: 10.1007/s00359-021-01493-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 05/23/2021] [Accepted: 05/26/2021] [Indexed: 10/21/2022]
Abstract
Multiple reports suggest that calcium-sensing receptors (CaSRs) are involved in calcium homeostasis, osmoregulation, and/or salinity sensing in fish (Loretz 2008, Herberger and Loretz 2013). We have isolated three unique full-length CaSR cDNAs from Atlantic salmon (Salmo salar) kidney that share many features with other reported CaSRs. Using anti-CaSR antibodies and PCR primers specific for individual salmon CaSR transcripts we show expression in osmoregulatory, neuroendocrine and sensory tissues. Furthermore, CaSRs are expressed in different patterns in salmon tissues where mRNA and protein expression are modified by freshwater or seawater acclimation. For example, in seawater, CaSR mRNA and protein expression is increased significantly in kidney as compared to freshwater. Electrophysiological recordings of olfactory responses produced upon exposure of salmon olfactory epithelium to CaSR agonists suggest a role for CaSRs in chemoreception in this species consistent with other freshwater, anadromous, and marine species where similar olfactory responses to divalent and polyvalent cations have been reported. These data provide further support for a role of CaSR proteins in osmoregulatory and sensory functions in Atlantic salmon, an anadromous species that experiences a broad range of environmental salinities in its life history.
Collapse
|
13
|
Calcium-Sensing Receptor (CaSR), Its Impact on Inflammation and the Consequences on Cardiovascular Health. Int J Mol Sci 2021; 22:ijms22052478. [PMID: 33804544 PMCID: PMC7957814 DOI: 10.3390/ijms22052478] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2021] [Revised: 02/11/2021] [Accepted: 02/25/2021] [Indexed: 12/15/2022] Open
Abstract
The calcium Sensing Receptor (CaSR) is a cell surface receptor belonging to the family of G-protein coupled receptors. CaSR is mainly expressed by parathyroid glands, kidneys, bone, skin, adipose tissue, the gut, the nervous system, and the cardiovascular system. The receptor, as its name implies is involved in sensing calcium fluctuations in the extracellular matrix of cells, thereby having a major impact on the mineral homeostasis in humans. Besides calcium ions, the receptor is also activated by other di- and tri-valent cations, polypeptides, polyamines, antibiotics, calcilytics and calcimimetics, which upon binding induce intracellular signaling pathways. Recent studies have demonstrated that CaSR influences a wide variety of cells and processes that are involved in inflammation, the cardiovascular system, such as vascular calcification, atherosclerosis, myocardial infarction, hypertension, and obesity. Therefore, in this review, the current understanding of the role that CaSR plays in inflammation and its consequences on the cardiovascular system will be highlighted.
Collapse
|
14
|
Abstract
Sensing and responding to changes in nutrient levels, including those of glucose, lipids, and amino acids, by the body is necessary for survival. Accordingly, perturbations in nutrient sensing are tightly linked with human pathologies, particularly metabolic diseases such as obesity, type 2 diabetes mellitus, and other complications of metabolic syndromes. The conventional view is that amino acids are fundamental elements for protein and peptide synthesis, while recent studies have revealed that amino acids are also important bioactive molecules that play key roles in signaling pathways and metabolic regulation. Different pathways that sense intracellular and extracellular levels of amino acids are integrated and coordinated at the organismal level, and, together, these pathways maintain whole metabolic homeostasis. In this review, we discuss the studies describing how important sensing signals respond to amino acid availability and how these sensing mechanisms modulate metabolic processes, including energy, glucose, and lipid metabolism. We further discuss whether dysregulation of amino acid sensing signals can be targeted to promote metabolic disorders, and discuss how to translate these mechanisms to treat human diseases. This review will help to enhance our overall understanding of the correlation between amino acid sensing and metabolic homeostasis, which have important implications for human health.
Collapse
Affiliation(s)
- Xiaoming Hu
- CAS Key Laboratory of Nutrition, Metabolism and Food Safety, Shanghai Institute of Nutrition and Health, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Feifan Guo
- CAS Key Laboratory of Nutrition, Metabolism and Food Safety, Shanghai Institute of Nutrition and Health, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| |
Collapse
|
15
|
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: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [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.
Collapse
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.)
| |
Collapse
|
16
|
Sensing Extracellular Calcium - An Insight into the Structure and Function of the Calcium-Sensing Receptor (CaSR). ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1131:1031-1063. [PMID: 31646544 DOI: 10.1007/978-3-030-12457-1_41] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The calcium-sensing receptor (CaSR) is a G protein-coupled receptor that plays a key role in calcium homeostasis, by sensing free calcium levels in blood and regulating parathyroid hormone secretion in response. The CaSR is highly expressed in parathyroid gland and kidney where its role is well characterised, but also in other tissues where its function remains to be determined. The CaSR can be activated by a variety of endogenous ligands, as well as by synthetic modulators such as Cinacalcet, used in the clinic to treat secondary hyperparathyroidism in patients with chronic kidney disease. The CaSR couples to multiple G proteins, in a tissue-specific manner, activating several signalling pathways and thus regulating diverse intracellular events. The multifaceted nature of this receptor makes it a valuable therapeutic target for calciotropic and non-calciotropic diseases. It is therefore essential to understand the complexity behind the pharmacology, trafficking, and signalling characteristics of this receptor. This review provides an overview of the latest knowledge about the CaSR and discusses future hot topics in this field.
Collapse
|
17
|
Sweet proteins lysozyme and thaumatin are protein-type agonists for the calcium-sensing receptor. Biochem Biophys Res Commun 2019; 521:227-231. [PMID: 31635806 DOI: 10.1016/j.bbrc.2019.10.111] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Accepted: 10/13/2019] [Indexed: 11/21/2022]
Abstract
In addition to the maintenance of Ca2+ homeostasis, the calcium-sensing receptor (CaSR) is involved in many diverse physiological functions in the mammalian body. The receptor works as a kokumi taste receptor in taste buds and as a nutrient sensor in the gut, where it regulates the secretion of glycemic response and appetite-related hormones. To identify novel human CaSR (hCaSR) activators from food ingredients, we conducted a screening using a cell-based hCaSR assay. Hen egg-white lysozyme, which is a sweet protein, was found to be a novel orthosteric agonist of hCaSR with an EC50 value of 592 μM. Lysozyme hydrolysate was not able to activate hCaSR, thus suggesting that the protein structure of lysozyme is necessary for hCaSR activation. Thaumatin, which is another sweet protein, also activated hCaSR with an EC50 value of 71 μM. This is the first report that shows hCaSR activation by proteins with molecular weights exceeding 10,000 Da. These results provide a new avenue for the development of hCaSR activators, which could be applicable in food or drugs that modulate taste perception, appetite, or glucose tolerance, in addition to Ca2+ homeostasis.
Collapse
|
18
|
Centeno PP, Herberger A, Mun HC, Tu C, Nemeth EF, Chang W, Conigrave AD, Ward DT. Phosphate acts directly on the calcium-sensing receptor to stimulate parathyroid hormone secretion. Nat Commun 2019; 10:4693. [PMID: 31619668 PMCID: PMC6795806 DOI: 10.1038/s41467-019-12399-9] [Citation(s) in RCA: 134] [Impact Index Per Article: 26.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Accepted: 09/05/2019] [Indexed: 02/06/2023] Open
Abstract
Extracellular phosphate regulates its own renal excretion by eliciting concentration-dependent secretion of parathyroid hormone (PTH). However, the phosphate-sensing mechanism remains unknown and requires elucidation for understanding the aetiology of secondary hyperparathyroidism in chronic kidney disease (CKD). The calcium-sensing receptor (CaSR) is the main controller of PTH secretion and here we show that raising phosphate concentration within the pathophysiologic range for CKD significantly inhibits CaSR activity via non-competitive antagonism. Mutation of residue R62 in anion binding site-1 abolishes phosphate-induced inhibition of CaSR. Further, pathophysiologic phosphate concentrations elicit rapid and reversible increases in PTH secretion from freshly-isolated human parathyroid cells consistent with a receptor-mediated action. The same effect is seen in wild-type murine parathyroid glands, but not in CaSR knockout glands. By sensing moderate changes in extracellular phosphate concentration, the CaSR represents a phosphate sensor in the parathyroid gland, explaining the stimulatory effect of phosphate on PTH secretion. Elevated inorganic phosphate levels promote excessive parathyroid hormone secretion, which contributes to the aetiology of secondary hyperparathyroidism. Here, the authors show that phosphate directly inhibits the calcium-sensing receptor, the main regulator of parathyroid hormone secretion.
Collapse
Affiliation(s)
- Patricia P Centeno
- Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK
| | - Amanda Herberger
- UCSF Department of Veterans Affairs Medical Center, San Francisco, CA, USA
| | - Hee-Chang Mun
- Charles Perkins Centre, University of Sydney, School of Life and Environmental Sciences, Sydney, NSW, Australia
| | - Chialing Tu
- UCSF Department of Veterans Affairs Medical Center, San Francisco, CA, USA
| | - Edward F Nemeth
- MetisMedica, 13 Poplar Plains Road, Toronto, ON, M4V 2M7, Canada
| | - Wenhan Chang
- UCSF Department of Veterans Affairs Medical Center, San Francisco, CA, USA
| | - Arthur D Conigrave
- Charles Perkins Centre, University of Sydney, School of Life and Environmental Sciences, Sydney, NSW, Australia
| | - Donald T Ward
- Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK.
| |
Collapse
|
19
|
Mun HC, Leach KM, Conigrave AD. L-Amino Acids Promote Calcitonin Release via a Calcium-Sensing Receptor: Gq/11-Mediated Pathway in Human C-Cells. Endocrinology 2019; 160:1590-1599. [PMID: 31127815 DOI: 10.1210/en.2018-00860] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Accepted: 04/19/2019] [Indexed: 11/19/2022]
Abstract
Human calcitonin release is promoted by elevated extracellular Ca2+ (Ca2+o) concentration acting, at least in part, via the calcium-sensing receptor (CaSR). The CaSR is positively modulated by L-amino acids, including the aromatic amino acids L-phenylalanine (Phe) and L-tryptophan (Trp). To investigate the effect of L-amino acids on human calcitonin secretion, we selected thyroid TT cells and exposed them to various Ca2+o concentrations in the absence or presence of L-Phe, plasma-like mixtures of L-amino acids, or the clinically effective positive modulator (calcimimetic) cinacalcet. In the presence of L-Phe or plasma-like mixtures of amino acids, TT cells exhibited enhanced Ca2+o sensitivity in assays of calcitonin release and intracellular Ca2+ mobilization. Furthermore, the effect of elevated Ca2+o and L-Phe on calcitonin release was markedly suppressed by the calcilytic NPS-2143. These effects were dependent on CaSR-mediated activation of Gq/11 as revealed by the specific inhibitor YM-254890. The findings support the hypothesis that calcitonin release is stimulated by increases in plasma L-amino acid levels as well as elevated Ca2+o concentration. They also demonstrate that stimulated calcitonin release as well as basal levels of calcitonin secretion are mediated by a CaSR:Gq/11 signaling mechanism.
Collapse
Affiliation(s)
- Hee-Chang Mun
- School of Life and Environmental Sciences, Charles Perkins Centre (D17), University of Sydney, Sydney, New South Wales, Australia
| | - Katie M Leach
- Drug Discovery Biology and Department of Pharmacology, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia
| | - Arthur D Conigrave
- School of Life and Environmental Sciences, Charles Perkins Centre (D17), University of Sydney, Sydney, New South Wales, Australia
| |
Collapse
|
20
|
Shen Q, Xiang W, Ye S, Lei X, Wang L, Jia S, Shao X, Weng C, Shen X, Wang Y, Feng S, Qu L, Wang C, Chen J, Zhang P, Jiang H. Plasma metabolite biomarkers related to secondary hyperparathyroidism and parathyroid hormone. J Cell Biochem 2019; 120:15766-15775. [PMID: 31069832 DOI: 10.1002/jcb.28846] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2018] [Revised: 02/11/2019] [Accepted: 02/14/2019] [Indexed: 11/08/2022]
Abstract
BACKGROUND Hyperphosphatemia, hypocalcemia, and elevation of parathyroid hormone (PTH) are typical abnormalities of uremic patients with Secondary hyperparathyroidism (SHPT). However, metabolic imbalance associated with SHPT is not well understood. METHODS A total of 15 SHPT patients with an intact parathyroid hormone (iPTH) level > 600 pg/mL were set as preoperative (PR) group, 15 age- and gender-matched controls who had undergone parathyroidectomy plus forearm transplantation because of hyperparathyroidism and achieved an iPTH level <150 pg/mL were set as postoperative (PO) group. Metabolite profiling of these 30 uremic patients and five healthy controls (HC) was performed using ultra performance liquid chromatography-mass spectrometry. RESULTS Five differential metabolites, including allyl isothiocyanate, L-phenylalanine, D-Aspartic acid, indoleacetaldehyde, and D-galactose correlated with PTH were identified in this study. Taking them as a biomarker signature, PR group can be distinguished from HC group with an area under the curve (AUC) of 0.947 (95% CI, 0.76-1) and PO group with an AUC of 0.6 (95% CI, 0.38-0.807). CONCLUSIONS The serum metabolome correlated with PTH is successfully demonstrated for a better understanding of the pathogenesis of SHPT.
Collapse
Affiliation(s)
- Qixia Shen
- Kidney Disease Center, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang, China.,Key Laboratory of Nephropathy, Hangzhou, Zhejiang, China.,Kidney Disease Immunology Laboratory, The Third-Grade Laboratory, State Administration of Traditional Chinese Medicine of China, Hangzhou, Zhejiang, China.,Key Laboratory of Multiple Organ Transplantation, Ministry of Health of China, Hangzhou, Zhejiang, China.,Institute of Nephropathy, Zhejiang University, Hangzhou, Zhejiang, China
| | - Wenyu Xiang
- Kidney Disease Center, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang, China.,Key Laboratory of Nephropathy, Hangzhou, Zhejiang, China.,Kidney Disease Immunology Laboratory, The Third-Grade Laboratory, State Administration of Traditional Chinese Medicine of China, Hangzhou, Zhejiang, China.,Key Laboratory of Multiple Organ Transplantation, Ministry of Health of China, Hangzhou, Zhejiang, China.,Institute of Nephropathy, Zhejiang University, Hangzhou, Zhejiang, China
| | - Sen Ye
- Kidney Disease Center, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang, China.,Key Laboratory of Nephropathy, Hangzhou, Zhejiang, China.,Kidney Disease Immunology Laboratory, The Third-Grade Laboratory, State Administration of Traditional Chinese Medicine of China, Hangzhou, Zhejiang, China.,Key Laboratory of Multiple Organ Transplantation, Ministry of Health of China, Hangzhou, Zhejiang, China.,Institute of Nephropathy, Zhejiang University, Hangzhou, Zhejiang, China
| | - Xin Lei
- Kidney Disease Center, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang, China.,Key Laboratory of Nephropathy, Hangzhou, Zhejiang, China.,Kidney Disease Immunology Laboratory, The Third-Grade Laboratory, State Administration of Traditional Chinese Medicine of China, Hangzhou, Zhejiang, China.,Key Laboratory of Multiple Organ Transplantation, Ministry of Health of China, Hangzhou, Zhejiang, China.,Institute of Nephropathy, Zhejiang University, Hangzhou, Zhejiang, China
| | - Lefeng Wang
- Kidney Disease Center, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang, China.,Key Laboratory of Nephropathy, Hangzhou, Zhejiang, China.,Kidney Disease Immunology Laboratory, The Third-Grade Laboratory, State Administration of Traditional Chinese Medicine of China, Hangzhou, Zhejiang, China.,Key Laboratory of Multiple Organ Transplantation, Ministry of Health of China, Hangzhou, Zhejiang, China.,Institute of Nephropathy, Zhejiang University, Hangzhou, Zhejiang, China
| | - Sha Jia
- Kidney Disease Center, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang, China.,Key Laboratory of Nephropathy, Hangzhou, Zhejiang, China.,Kidney Disease Immunology Laboratory, The Third-Grade Laboratory, State Administration of Traditional Chinese Medicine of China, Hangzhou, Zhejiang, China.,Key Laboratory of Multiple Organ Transplantation, Ministry of Health of China, Hangzhou, Zhejiang, China.,Institute of Nephropathy, Zhejiang University, Hangzhou, Zhejiang, China
| | - Xue Shao
- Kidney Disease Center, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang, China.,Key Laboratory of Nephropathy, Hangzhou, Zhejiang, China.,Kidney Disease Immunology Laboratory, The Third-Grade Laboratory, State Administration of Traditional Chinese Medicine of China, Hangzhou, Zhejiang, China.,Key Laboratory of Multiple Organ Transplantation, Ministry of Health of China, Hangzhou, Zhejiang, China.,Institute of Nephropathy, Zhejiang University, Hangzhou, Zhejiang, China
| | - Chunhua Weng
- Kidney Disease Center, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang, China.,Key Laboratory of Nephropathy, Hangzhou, Zhejiang, China.,Kidney Disease Immunology Laboratory, The Third-Grade Laboratory, State Administration of Traditional Chinese Medicine of China, Hangzhou, Zhejiang, China.,Key Laboratory of Multiple Organ Transplantation, Ministry of Health of China, Hangzhou, Zhejiang, China.,Institute of Nephropathy, Zhejiang University, Hangzhou, Zhejiang, China
| | - Xiujin Shen
- Kidney Disease Center, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang, China.,Key Laboratory of Nephropathy, Hangzhou, Zhejiang, China.,Kidney Disease Immunology Laboratory, The Third-Grade Laboratory, State Administration of Traditional Chinese Medicine of China, Hangzhou, Zhejiang, China.,Key Laboratory of Multiple Organ Transplantation, Ministry of Health of China, Hangzhou, Zhejiang, China.,Institute of Nephropathy, Zhejiang University, Hangzhou, Zhejiang, China
| | - Yucheng Wang
- Kidney Disease Center, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang, China.,Key Laboratory of Nephropathy, Hangzhou, Zhejiang, China.,Kidney Disease Immunology Laboratory, The Third-Grade Laboratory, State Administration of Traditional Chinese Medicine of China, Hangzhou, Zhejiang, China.,Key Laboratory of Multiple Organ Transplantation, Ministry of Health of China, Hangzhou, Zhejiang, China.,Institute of Nephropathy, Zhejiang University, Hangzhou, Zhejiang, China
| | - Shi Feng
- Kidney Disease Center, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang, China.,Key Laboratory of Nephropathy, Hangzhou, Zhejiang, China.,Kidney Disease Immunology Laboratory, The Third-Grade Laboratory, State Administration of Traditional Chinese Medicine of China, Hangzhou, Zhejiang, China.,Key Laboratory of Multiple Organ Transplantation, Ministry of Health of China, Hangzhou, Zhejiang, China.,Institute of Nephropathy, Zhejiang University, Hangzhou, Zhejiang, China
| | - Lihui Qu
- Kidney Disease Center, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang, China.,Key Laboratory of Nephropathy, Hangzhou, Zhejiang, China.,Kidney Disease Immunology Laboratory, The Third-Grade Laboratory, State Administration of Traditional Chinese Medicine of China, Hangzhou, Zhejiang, China.,Key Laboratory of Multiple Organ Transplantation, Ministry of Health of China, Hangzhou, Zhejiang, China.,Institute of Nephropathy, Zhejiang University, Hangzhou, Zhejiang, China
| | - Cuili Wang
- Kidney Disease Center, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang, China.,Key Laboratory of Nephropathy, Hangzhou, Zhejiang, China.,Kidney Disease Immunology Laboratory, The Third-Grade Laboratory, State Administration of Traditional Chinese Medicine of China, Hangzhou, Zhejiang, China.,Key Laboratory of Multiple Organ Transplantation, Ministry of Health of China, Hangzhou, Zhejiang, China.,Institute of Nephropathy, Zhejiang University, Hangzhou, Zhejiang, China
| | - Jianghua Chen
- Kidney Disease Center, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang, China.,Key Laboratory of Nephropathy, Hangzhou, Zhejiang, China.,Kidney Disease Immunology Laboratory, The Third-Grade Laboratory, State Administration of Traditional Chinese Medicine of China, Hangzhou, Zhejiang, China.,Key Laboratory of Multiple Organ Transplantation, Ministry of Health of China, Hangzhou, Zhejiang, China.,Institute of Nephropathy, Zhejiang University, Hangzhou, Zhejiang, China
| | - Ping Zhang
- Kidney Disease Center, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang, China.,Key Laboratory of Nephropathy, Hangzhou, Zhejiang, China.,Kidney Disease Immunology Laboratory, The Third-Grade Laboratory, State Administration of Traditional Chinese Medicine of China, Hangzhou, Zhejiang, China.,Key Laboratory of Multiple Organ Transplantation, Ministry of Health of China, Hangzhou, Zhejiang, China.,Institute of Nephropathy, Zhejiang University, Hangzhou, Zhejiang, China
| | - Hong Jiang
- Kidney Disease Center, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang, China.,Key Laboratory of Nephropathy, Hangzhou, Zhejiang, China.,Kidney Disease Immunology Laboratory, The Third-Grade Laboratory, State Administration of Traditional Chinese Medicine of China, Hangzhou, Zhejiang, China.,Key Laboratory of Multiple Organ Transplantation, Ministry of Health of China, Hangzhou, Zhejiang, China.,Institute of Nephropathy, Zhejiang University, Hangzhou, Zhejiang, China
| |
Collapse
|
21
|
Evolving Role of Vitamin D in Immune-Mediated Disease and Its Implications in Autoimmune Hepatitis. Dig Dis Sci 2019; 64:324-344. [PMID: 30370494 DOI: 10.1007/s10620-018-5351-6] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Accepted: 10/09/2018] [Indexed: 12/11/2022]
Abstract
Vitamin D has immunomodulatory, anti-inflammatory, antioxidant, and anti-fibrotic actions that may impact on the occurrence and outcome of immune-mediated disease. The goals of this review are to describe the nature of these expanded roles, examine the implications of vitamin D deficiency in autoimmune hepatitis, and identify opportunities for future investigation. Abstracts were identified in PubMed by multiple search terms. Full-length articles were selected for review, and secondary and tertiary bibliographies were developed. Vitamin D receptors are expressed on the principal cell populations involved in the innate and adaptive immune responses. Macrophages and dendritic cells can produce 1,25-dihydroxyvitamin D within the microenvironment. This active form of vitamin D can inhibit immune cell proliferation, promote an anti-inflammatory cytokine profile, expand regulatory T cells, enhance glucocorticoid actions, increase glutathione production, and inhibit hepatic stellate cells. Vitamin D deficiency has been commonly present in patients with immune-mediated liver and non-liver diseases, and it has been associated with histological severity, advanced hepatic fibrosis, and non-response to conventional glucocorticoid therapy in autoimmune hepatitis. Vitamin D analogues with high potency, low calcemic effects, and independence from hepatic hydroxylation are possible interventions. In conclusion, vitamin D has properties that could ameliorate immune-mediated disease, and vitamin D deficiency has been a common finding in immune-mediated liver and non-liver diseases, including autoimmune hepatitis. Loss of vitamin D-dependent homeostatic mechanisms may promote disease progression. Vitamin D analogues that are independent of hepatic hydroxylation constitute an investigational opportunity to supplement current management of autoimmune hepatitis.
Collapse
|
22
|
Keller AN, Kufareva I, Josephs TM, Diao J, Mai VT, Conigrave AD, Christopoulos A, Gregory KJ, Leach K. Identification of Global and Ligand-Specific Calcium Sensing Receptor Activation Mechanisms. Mol Pharmacol 2018; 93:619-630. [PMID: 29636377 DOI: 10.1124/mol.118.112086] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Accepted: 04/06/2018] [Indexed: 12/11/2022] Open
Abstract
Calcium sensing receptor (CaSR) positive allosteric modulators (PAMs) are therapeutically important. However, few are approved for clinical use, in part due to complexities in assessing allostery at a receptor where the endogenous agonist (extracellular calcium) is present in all biologic fluids. Such complexity impedes efforts to quantify and optimize allosteric drug parameters (affinity, cooperativity, and efficacy) that dictate PAM structure-activity relationships (SARs). Furthermore, an underappreciation of the structural mechanisms underlying CaSR activation hinders predictions of how PAM SAR relates to in vitro and in vivo activity. Herein, we combined site-directed mutagenesis and calcium mobilization assays with analytical pharmacology to compare modes of PAM binding, positive modulation, and agonism. We demonstrate that 3-(2-chlorophenyl)-N-((1R)-1-(3-methoxyphenyl)ethyl)-1-propanamine (NPS R568) binds to a 7 transmembrane domain (7TM) cavity common to class C G protein-coupled receptors and used by (αR)-(-)-α-methyl-N-[3-[3-[trifluoromethylphenyl]propyl]-1-napthalenemethanamine (cinacalcet) and 1-benzothiazol-2-yl-1-(2,4-dimethylphenyl)-ethanol (AC265347); however, there are subtle distinctions in the contribution of select residues to the binding and transmission of cooperativity by PAMs. Furthermore, we reveal some common activation mechanisms used by different CaSR activators, but also demonstrate some differential contributions of residues within the 7TM bundle and extracellular loops to the efficacy of the PAM-agonist, AC265347, versus cooperativity. Finally, we show that PAMS potentiate the affinity of divalent cations. Our results support the existence of both global and ligand-specific CaSR activation mechanisms and reveal that allosteric agonism is mediated in part via distinct mechanisms to positive modulation.
Collapse
Affiliation(s)
- Andrew N Keller
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences and Department of Pharmacology, Monash University, Parkville, Victoria, Australia (A.N.K., T.M.J., J.D., V.T.M., A.C., K.J.G., K.L.); Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, La Jolla, San Diego, California (I.K.); and School of Life and Environmental Sciences, Charles Perkins Centre (D17), University of Sydney, New South Wales, Australia (A.D.C.)
| | - Irina Kufareva
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences and Department of Pharmacology, Monash University, Parkville, Victoria, Australia (A.N.K., T.M.J., J.D., V.T.M., A.C., K.J.G., K.L.); Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, La Jolla, San Diego, California (I.K.); and School of Life and Environmental Sciences, Charles Perkins Centre (D17), University of Sydney, New South Wales, Australia (A.D.C.)
| | - Tracy M Josephs
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences and Department of Pharmacology, Monash University, Parkville, Victoria, Australia (A.N.K., T.M.J., J.D., V.T.M., A.C., K.J.G., K.L.); Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, La Jolla, San Diego, California (I.K.); and School of Life and Environmental Sciences, Charles Perkins Centre (D17), University of Sydney, New South Wales, Australia (A.D.C.)
| | - Jiayin Diao
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences and Department of Pharmacology, Monash University, Parkville, Victoria, Australia (A.N.K., T.M.J., J.D., V.T.M., A.C., K.J.G., K.L.); Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, La Jolla, San Diego, California (I.K.); and School of Life and Environmental Sciences, Charles Perkins Centre (D17), University of Sydney, New South Wales, Australia (A.D.C.)
| | - Vyvyan T Mai
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences and Department of Pharmacology, Monash University, Parkville, Victoria, Australia (A.N.K., T.M.J., J.D., V.T.M., A.C., K.J.G., K.L.); Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, La Jolla, San Diego, California (I.K.); and School of Life and Environmental Sciences, Charles Perkins Centre (D17), University of Sydney, New South Wales, Australia (A.D.C.)
| | - Arthur D Conigrave
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences and Department of Pharmacology, Monash University, Parkville, Victoria, Australia (A.N.K., T.M.J., J.D., V.T.M., A.C., K.J.G., K.L.); Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, La Jolla, San Diego, California (I.K.); and School of Life and Environmental Sciences, Charles Perkins Centre (D17), University of Sydney, New South Wales, Australia (A.D.C.)
| | - Arthur Christopoulos
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences and Department of Pharmacology, Monash University, Parkville, Victoria, Australia (A.N.K., T.M.J., J.D., V.T.M., A.C., K.J.G., K.L.); Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, La Jolla, San Diego, California (I.K.); and School of Life and Environmental Sciences, Charles Perkins Centre (D17), University of Sydney, New South Wales, Australia (A.D.C.)
| | - Karen J Gregory
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences and Department of Pharmacology, Monash University, Parkville, Victoria, Australia (A.N.K., T.M.J., J.D., V.T.M., A.C., K.J.G., K.L.); Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, La Jolla, San Diego, California (I.K.); and School of Life and Environmental Sciences, Charles Perkins Centre (D17), University of Sydney, New South Wales, Australia (A.D.C.)
| | - Katie Leach
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences and Department of Pharmacology, Monash University, Parkville, Victoria, Australia (A.N.K., T.M.J., J.D., V.T.M., A.C., K.J.G., K.L.); Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, La Jolla, San Diego, California (I.K.); and School of Life and Environmental Sciences, Charles Perkins Centre (D17), University of Sydney, New South Wales, Australia (A.D.C.)
| |
Collapse
|
23
|
Rasmussen AQ, Jørgensen NR, Schwarz P. Identification and Functional Characterization of a Novel Mutation in the Human Calcium-Sensing Receptor That Co-Segregates With Autosomal-Dominant Hypocalcemia. Front Endocrinol (Lausanne) 2018; 9:200. [PMID: 29743878 PMCID: PMC5930847 DOI: 10.3389/fendo.2018.00200] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Accepted: 04/10/2018] [Indexed: 12/31/2022] Open
Abstract
The human calcium-sensing receptor (CASR) is the key controller of extracellular Cao2+ homeostasis, and different mutations in the CASR gene have been linked to different calcium diseases, such as familial hypocalciuric hypercalcemia, severe hyperparathyroidism, autosomal-dominant hypocalcemia (ADH), and Bartter's syndrome type V. In this study, two generations of a family with biochemically and clinically confirmed ADH who suffered severe muscle pain, arthralgia, tetany, abdominal pain, and fatigue were evaluated for mutations in the CASR gene. The study comprises genotyping of all family members, functional characterization of a potential mutant receptor by in vitro analysis related to the wild-type receptor to reveal an association between the genotype and phenotype in the affected family members. The in vitro analysis of functional characteristics includes measurements of inositol trisphosphate accumulation, Ca2+ mobilization in response to [Ca2+]o-stimulation and receptor expression. The results reveal a significant leftward shift of inositol trisphosphate accumulation as a result of the "gain-of-function" mutant receptor and surprisingly a normalization of the response in (Ca2+)i release in the downstream pathway and additionally the maximal response of (Ca2+)i release was significantly decreased compared to the wild type. However, no gross differences were seen in D126V and the D126V/WT CASR dimeric >250 kDa band expression compared to the WT receptor, however, the D126V and D126V/WT CASR immature ~140 kDa species appear to have reduced expression compared to the WT receptor. In conclusion, in this study, a family with a clinical diagnosis of ADH in two generations was evaluated to identify a mutation in the CASR gene and reveal an association between genotype and phenotype in the affected family members. The clinical condition was caused by a novel, activating, missense mutation (D126V) in the CASR gene and the in vitro functional characteristics of the mutation co-segregated with their individual phenotype.
Collapse
Affiliation(s)
- Anne Qvist Rasmussen
- Research Centre of Ageing and Osteoporosis, Department of Endocrinology, Rigshospitalet, Copenhagen, Denmark
- *Correspondence: Anne Qvist Rasmussen,
| | - Niklas Rye Jørgensen
- Department of Clinical Biochemistry, Rigshospitalet, Copenhagen, Denmark
- Institute of Clinical Research, University of Southern, Odense, Denmark
| | - Peter Schwarz
- Research Centre of Ageing and Osteoporosis, Department of Endocrinology, Rigshospitalet, Copenhagen, Denmark
- Faculty of Health Sciences, Copenhagen University, Copenhagen, Denmark
| |
Collapse
|
24
|
Guo CL, Li YT, Lin XY, Hanigan MD, Yan ZG, Hu ZY, Hou QL, Jiang FG, Wang ZH. Effects of graded removal of lysine from an intravenously infused amino acid mixture on lactation performance and mammary amino acid metabolism in lactating goats. J Dairy Sci 2017; 100:4552-4564. [PMID: 28434735 DOI: 10.3168/jds.2016-11921] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Accepted: 02/22/2017] [Indexed: 12/21/2022]
Abstract
To investigate responses of milk protein synthesis and mammary AA metabolism to a graded decrease of postruminal Lys supply, 4 lactating goats fitted with jugular vein, mammary vein, and carotid artery catheters and transonic blood flow detectors on the external pudic artery were used in a 4 × 4 Latin square experiment. Goats were fasted for 24 h and then received a 9-h intravenous infusion of an AA mixture plus glucose. Milk yield was recorded and samples were taken in h 2 to 8 of the infusion period; a mammary biopsy was performed in the last hour. Treatments were graded decrease of lysine content in the infusate to 100 (complete), 60, 30, or 0% as in casein. Lysine-removed infusions linearly decreased milk yield, tended to decrease lactose yield, and tended to increase milk fat to protein ratio. Milk protein content and yield were linearly decreased by graded Lys deficiency. Mammary Lys uptake was concomitantly decreased, but linear regression analysis found no significant relationship between mammary Lys uptake and milk protein yield. Treatments had no effects on phosphorylation levels of the downstream proteins measured in the mammalian target or rapamycin pathway except for a tended quadratic effect on that of eukaryotic initiation factor 2, which was increased and then decreased by graded Lys deficiency. Removal of Lys from the infusate linearly increased circulating glucagon and glucose. Removal of Lys from the infusate linearly decreased arterial and venous concentrations of Lys. Treatments also had a significant quadratic effect on venous Lys, suggesting mechanisms to stabilize circulating Lys at a certain range. The 2 infusions partially removing Lys resulted in a similar 20% decrease, whereas the 0% Lys infusion resulted in an abrupt 70% decrease in mammary Lys uptake compared with that of the full-AA mixture infusion. Consistent with the abrupt decrease, mammary Lys uptake-to-output ratio decreased from 2.2 to 0.92, suggesting catabolism of Lys in the mammary gland could be completely prevented when the animal faced severe Lys deficiency. Mammary blood flow was linearly increased, consistent with the linearly increased circulating nitric oxide by graded Lys deficiency, indicating mechanisms to ensure the priority of the mammary gland in acquiring AA for milk protein synthesis. Infusions with Lys removed increased mammary clearance rate of Lys numerically by 2 to 3 fold. In conclusion, the decreased milk protein yield by graded Lys deficiency was mainly a result of the varied physiological status, as indicated by the elevated circulating glucagon and glucose, rather than a result of the decreased mammary Lys uptake or depressed signals in the mTOR pathway. Mechanisms of Lys deficiency to promote glucagon secretion and mammary blood flow and glucagon to depress milk protein synthesis need to be clarified by future studies.
Collapse
Affiliation(s)
- C L Guo
- Ruminant Nutrition and Physiology Laboratory, College of Animal Science and Technology, Shandong Agricultural University, Taian 271018, P. R. China
| | - Y T Li
- Ruminant Nutrition and Physiology Laboratory, College of Animal Science and Technology, Shandong Agricultural University, Taian 271018, P. R. China
| | - X Y Lin
- Ruminant Nutrition and Physiology Laboratory, College of Animal Science and Technology, Shandong Agricultural University, Taian 271018, P. R. China
| | - M D Hanigan
- Department of Dairy Science, Virginia Tech, Blacksburg 24061
| | - Z G Yan
- Ruminant Nutrition and Physiology Laboratory, College of Animal Science and Technology, Shandong Agricultural University, Taian 271018, P. R. China
| | - Z Y Hu
- Ruminant Nutrition and Physiology Laboratory, College of Animal Science and Technology, Shandong Agricultural University, Taian 271018, P. R. China
| | - Q L Hou
- Ruminant Nutrition and Physiology Laboratory, College of Animal Science and Technology, Shandong Agricultural University, Taian 271018, P. R. China
| | - F G Jiang
- Ruminant Nutrition and Physiology Laboratory, College of Animal Science and Technology, Shandong Agricultural University, Taian 271018, P. R. China
| | - Z H Wang
- Ruminant Nutrition and Physiology Laboratory, College of Animal Science and Technology, Shandong Agricultural University, Taian 271018, P. R. China.
| |
Collapse
|
25
|
Leach K, Gregory KJ. Molecular insights into allosteric modulation of Class C G protein-coupled receptors. Pharmacol Res 2017; 116:105-118. [DOI: 10.1016/j.phrs.2016.12.006] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2016] [Revised: 11/18/2016] [Accepted: 12/07/2016] [Indexed: 12/23/2022]
|
26
|
Conigrave AD. The Calcium-Sensing Receptor and the Parathyroid: Past, Present, Future. Front Physiol 2016; 7:563. [PMID: 28018229 PMCID: PMC5156698 DOI: 10.3389/fphys.2016.00563] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2016] [Accepted: 11/07/2016] [Indexed: 12/13/2022] Open
Abstract
Parathyroid hormone (PTH) defends the extracellular fluid from hypocalcemia and has powerful and well-documented actions on the skeleton and renal tubular system. To achieve a satisfactory stable plasma calcium level, the secretion of PTH, and the resulting serum PTH level, is titrated carefully to the prevailing plasma ionized Ca2+ concentration via a Ca2+ sensing mechanism that mediates feedback inhibition of PTH secretion. Herein, I consider the properties of the parathyroid Ca2+ sensing mechanism, the identity of the Ca2+ sensor, the intracellular biochemical mechanisms that it controls, the manner of its integration with other components of the PTH secretion control mechanism, and its modulation by other nutrients. Together the well-established, recently elucidated, and yet-to-be discovered elements of the story constitute the past, present, and future of the parathyroid and its calcium-sensing receptor (CaSR).
Collapse
Affiliation(s)
- Arthur D Conigrave
- Faculties of Science and Medicine, School of Life and Environmental Sciences, Charles Perkins Centre, University of Sydney Sydney, NSW, Australia
| |
Collapse
|
27
|
Geng Y, Mosyak L, Kurinov I, Zuo H, Sturchler E, Cheng TC, Subramanyam P, Brown AP, Brennan SC, Mun HC, Bush M, Chen Y, Nguyen TX, Cao B, Chang DD, Quick M, Conigrave AD, Colecraft HM, McDonald P, Fan QR. Structural mechanism of ligand activation in human calcium-sensing receptor. eLife 2016; 5. [PMID: 27434672 PMCID: PMC4977154 DOI: 10.7554/elife.13662] [Citation(s) in RCA: 155] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Accepted: 07/18/2016] [Indexed: 12/21/2022] Open
Abstract
Human calcium-sensing receptor (CaSR) is a G-protein-coupled receptor (GPCR) that maintains extracellular Ca2+ homeostasis through the regulation of parathyroid hormone secretion. It functions as a disulfide-tethered homodimer composed of three main domains, the Venus Flytrap module, cysteine-rich domain, and seven-helix transmembrane region. Here, we present the crystal structures of the entire extracellular domain of CaSR in the resting and active conformations. We provide direct evidence that L-amino acids are agonists of the receptor. In the active structure, L-Trp occupies the orthosteric agonist-binding site at the interdomain cleft and is primarily responsible for inducing extracellular domain closure to initiate receptor activation. Our structures reveal multiple binding sites for Ca2+ and PO43- ions. Both ions are crucial for structural integrity of the receptor. While Ca2+ ions stabilize the active state, PO43- ions reinforce the inactive conformation. The activation mechanism of CaSR involves the formation of a novel dimer interface between subunits. DOI:http://dx.doi.org/10.7554/eLife.13662.001 Calcium ions regulate many processes in the human body. The calcium-sensing receptor, called CaSR, is responsible for maintaining a stable level of calcium ions in the blood. This receptor can detect small changes in the concentration of calcium ions, and activates signalling events within the cell to restore the level of calcium ions back to normal. Abnormal activity of this receptor is associated with severe diseases in humans CaSR is found in the surface membrane of cells and belongs to a family of proteins called G-protein coupled receptors. Much of the protein extends out of the cell and interacts with calcium ions, phosphate ions and certain other molecules such as amino acids. However, it was not well understood how these small molecules bind to CaSR and how this activates the receptor. Geng et al. have now used a technique called X-ray crystallography to view the three-dimensional structure of the exterior domain of CaSR in its resting state and active state. These structures revealed that, contrary to expectations, calcium ions are not the main activator of the receptor. Instead, Geng et al. found that CaSR adopts an inactive state in the absence or presence of calcium ions, while the active state only forms when an amino acid is bound. Furthermore investigation showed that calcium ions are needed to stabilise the active form, while phosphate ions keep the inactive form stable. Geng et al. also identified the shape changes that must occur as CaSR transitions from its inactive to its active state. In particular, an amino acid binding to the exterior domain causes it to close like a venus flytrap, which is a crucial step in activating the receptor. Taken together, the findings show that the amino acids and calcium ions act jointly to fully activate CaSR. The next steps are to determine the structure of the entire receptor with and without its small molecule partners and to use these structures to design drugs that can alter CaSR’s activity in order to treat human diseases. DOI:http://dx.doi.org/10.7554/eLife.13662.002
Collapse
Affiliation(s)
- Yong Geng
- Department of Pharmacology, Columbia University, New York, United States.,Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Lidia Mosyak
- Department of Pharmacology, Columbia University, New York, United States
| | - Igor Kurinov
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, United States
| | - Hao Zuo
- Department of Pharmacology, Columbia University, New York, United States
| | - Emmanuel Sturchler
- Department of Molecular Therapeutics, The Scripps Translational Science Institute, Jupiter, United States
| | - Tat Cheung Cheng
- Department of Pharmacology, Columbia University, New York, United States
| | - Prakash Subramanyam
- Department of Physiology and Cellular Biophysics, Columbia University, New York, United States
| | - Alice P Brown
- School of Life and Environmental Sciences, University of Sydney, New South Wales, Australia
| | - Sarah C Brennan
- School of Life and Environmental Sciences, University of Sydney, New South Wales, Australia
| | - Hee-Chang Mun
- School of Life and Environmental Sciences, University of Sydney, New South Wales, Australia
| | - Martin Bush
- Department of Pharmacology, Columbia University, New York, United States
| | - Yan Chen
- Department of Pharmacology, Columbia University, New York, United States
| | - Trang X Nguyen
- Department of Psychiatry, Columbia University, New York, United States
| | - Baohua Cao
- Department of Pharmacology, Columbia University, New York, United States
| | - Donald D Chang
- Department of Physiology and Cellular Biophysics, Columbia University, New York, United States
| | - Matthias Quick
- Department of Psychiatry, Columbia University, New York, United States
| | - Arthur D Conigrave
- School of Life and Environmental Sciences, University of Sydney, New South Wales, Australia
| | - Henry M Colecraft
- Department of Physiology and Cellular Biophysics, Columbia University, New York, United States
| | - Patricia McDonald
- Department of Molecular Therapeutics, The Scripps Translational Science Institute, Jupiter, United States
| | - Qing R Fan
- Department of Pharmacology, Columbia University, New York, United States.,Department of Pathology and Cell Biology, Columbia University, New York, United States
| |
Collapse
|
28
|
Abstract
The present review examines the pig as a model for physiological studies in human subjects related to nutrient sensing, appetite regulation, gut barrier function, intestinal microbiota and nutritional neuroscience. The nutrient-sensing mechanisms regarding acids (sour), carbohydrates (sweet), glutamic acid (umami) and fatty acids are conserved between humans and pigs. In contrast, pigs show limited perception of high-intensity sweeteners and NaCl and sense a wider array of amino acids than humans. Differences on bitter taste may reflect the adaptation to ecosystems. In relation to appetite regulation, plasma concentrations of cholecystokinin and glucagon-like peptide-1 are similar in pigs and humans, while peptide YY in pigs is ten to twenty times higher and ghrelin two to five times lower than in humans. Pigs are an excellent model for human studies for vagal nerve function related to the hormonal regulation of food intake. Similarly, the study of gut barrier functions reveals conserved defence mechanisms between the two species particularly in functional permeability. However, human data are scant for some of the defence systems and nutritional programming. The pig model has been valuable for studying the changes in human microbiota following nutritional interventions. In particular, the use of human flora-associated pigs is a useful model for infants, but the long-term stability of the implanted human microbiota in pigs remains to be investigated. The similarity of the pig and human brain anatomy and development is paradigmatic. Brain explorations and therapies described in pig, when compared with available human data, highlight their value in nutritional neuroscience, particularly regarding functional neuroimaging techniques.
Collapse
|
29
|
Chemosensory signalling pathways involved in sensing of amino acids by the ghrelin cell. Sci Rep 2015; 5:15725. [PMID: 26510380 PMCID: PMC4625164 DOI: 10.1038/srep15725] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Accepted: 10/01/2015] [Indexed: 01/06/2023] Open
Abstract
Taste receptors on enteroendocrine cells sense nutrients and transmit signals that control gut hormone release. This study aimed to investigate the amino acid (AA) sensing mechanisms of the ghrelin cell in a gastric ghrelinoma cell line, tissue segments and mice. Peptone and specific classes of amino acids stimulate ghrelin secretion in the ghrelinoma cell line. Sensing of L-Phe occurs via the CaSR, monosodium glutamate via the TAS1R1-TAS1R3 while L-Ala and peptone act via 2 different amino acid taste receptors: CaSR &TAS1R1-TAS1R3 and CaSR &GPRC6A, respectively. The stimulatory effect of peptone on ghrelin release was mimicked ex vivo in gastric but not in jejunal tissue segments, where peptone inhibited ghrelin release. The latter effect could not be blocked by receptor antagonists for CCK, GLP-1 or somatostatin. In vivo, plasma ghrelin levels were reduced both upon intragastric (peptone or L-Phe) or intravenous (L-Phe) administration, indicating that AA- sensing is not polarized and is due to inhibition of ghrelin release from the stomach or duodenum respectively. In conclusion, functional AA taste receptors regulate AA-induced ghrelin release in vitro. The effects differ between stomach and jejunum but these local nutrient sensing mechanisms are overruled in vivo by indirect mechanisms inhibiting ghrelin release.
Collapse
|
30
|
Alexander ST, Hunter T, Walter S, Dong J, Maclean D, Baruch A, Subramanian R, Tomlinson JE. Critical Cysteine Residues in Both the Calcium-Sensing Receptor and the Allosteric Activator AMG 416 Underlie the Mechanism of Action. Mol Pharmacol 2015; 88:853-65. [DOI: 10.1124/mol.115.098392] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Accepted: 08/18/2015] [Indexed: 01/18/2023] Open
|
31
|
Gaffney-Stomberg E, Cao JJ, Lin GG, Wulff CR, Murphy NE, Young AJ, McClung JP, Pasiakos SM. Dietary protein level and source differentially affect bone metabolism, strength, and intestinal calcium transporter expression during ad libitum and food-restricted conditions in male rats. J Nutr 2014; 144:821-9. [PMID: 24717364 DOI: 10.3945/jn.113.188532] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
High-protein (HP) diets may attenuate bone loss during energy restriction. The objective of the current study was to determine whether HP diets suppress bone turnover and improve bone quality in male rats during food restriction and whether dietary protein source affects this relation. Eighty 12-wk-old male Sprague Dawley rats were randomly assigned to consume 1 of 4 study diets under ad libitum (AL) control or restricted conditions [40% food restriction (FR)]: 1) 10% [normal-protein (NP)] milk protein; 2) 32% (HP) milk protein; 3) 10% (NP) soy protein; or 4) 32% (HP) soy protein. After 16 wk, markers of bone turnover, volumetric bone mineral density (vBMD), microarchitecture, strength, and expression of duodenal calcium channels were assessed. FR increased bone turnover and resulted in lower femoral trabecular bone volume (P < 0.05), higher cortical bone surface (P < 0.001), and reduced femur length (P < 0.01), bending moment (P < 0.05), and moment of inertia (P = 0.001) compared with AL. HP intake reduced bone turnover and tended to suppress parathyroid hormone (PTH) (P = 0.06) and increase trabecular vBMD (P < 0.05) compared with NP but did not affect bone strength. Compared with milk, soy suppressed PTH (P < 0.05) and increased cortical vBMD (P < 0.05) and calcium content of the femur (P < 0.01) but did not affect strength variables. During AL conditions, transient receptor potential cation channel, subfamily V, member 6 was higher for soy than milk (P < 0.05) and HP compared with NP (P < 0.05). These data demonstrate that both HP and soy diets suppress PTH, and HP attenuates bone turnover and increases vBMD regardless of FR, although these differences do not affect bone strength. The effects of HP and soy may be due in part to enhanced intestinal calcium transporter expression.
Collapse
Affiliation(s)
- Erin Gaffney-Stomberg
- U.S. Army Research Institute of Environmental Medicine, Military Nutrition Division, Natick, MA; and
| | - Jay J Cao
- USDA Agricultural Research Service Grand Forks Human Nutrition Research Center, Grand Forks, ND
| | - Gregory G Lin
- U.S. Army Research Institute of Environmental Medicine, Military Nutrition Division, Natick, MA; and
| | - Charles R Wulff
- U.S. Army Research Institute of Environmental Medicine, Military Nutrition Division, Natick, MA; and
| | - Nancy E Murphy
- U.S. Army Research Institute of Environmental Medicine, Military Nutrition Division, Natick, MA; and
| | - Andrew J Young
- U.S. Army Research Institute of Environmental Medicine, Military Nutrition Division, Natick, MA; and
| | - James P McClung
- U.S. Army Research Institute of Environmental Medicine, Military Nutrition Division, Natick, MA; and
| | - Stefan M Pasiakos
- U.S. Army Research Institute of Environmental Medicine, Military Nutrition Division, Natick, MA; and
| |
Collapse
|
32
|
Rouy E, Vico L, Laroche N, Benoit V, Rousseau B, Blachier F, Tomé D, Blais A. Protein quality affects bone status during moderate protein restriction in growing mice. Bone 2014; 59:7-13. [PMID: 24495359 DOI: 10.1016/j.bone.2013.10.013] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/05/2013] [Revised: 10/16/2013] [Accepted: 10/16/2013] [Indexed: 01/16/2023]
Abstract
Adequate protein intake during development is critical to ensure optimal bone gain and to attain a higher peak bone mass later on. We hypothesized that the quality of the dietary protein is of prime importance for bone physiology during moderate protein restriction. The target population was growing Balb/C mice. We compared two protein restricted diets (6% of total energy as protein), one based on soy (LP-SOY) and one based on casein (LP-CAS). For comparison, a normal protein soy-based control group (NP-SOY) and a low protein group receiving an anabolic daily parathyroid hormone (PTH) 1-34 injection (LP-SOY+PTH) were included in the protocol. After 8weeks, LP-SOY mice had reduced body weights related to a lower lean mass whereas LP-CAS mice were not different from the NP-SOY group. LP-SOY mice were characterized by lower femoral cortical thickness, bone volume, trabecular number and thickness and increased medullar adiposity when compared to both the LP-CAS and NP-SOY groups. However, the dietary intervention had no effect on the vertebral parameters. The negative effect of the LP-SOY diet was correlated to an impaired bone formation as shown by the reduced P1NP serum level as well as the reduced osteoid surfaces and bone formation rate in the femur. PTH injection in LP-SOY mice had no effect on total weight or lean mass, but improved all bone parameters at both femoral and vertebral sites, suggesting that amino acid deficiency was not the primary reason for degraded bone status in mice consuming soy protein. In conclusion, our study showed that under the same protein restriction (6% of energy), a soy diet leads to impaired bone health whereas a casein diet has little effect when compared to a normal protein control.
Collapse
Affiliation(s)
- Emilien Rouy
- UMR 914 INRA-AgroParisTech, Nutrition Physiology and Ingestive Behavior, 75005 Paris, France; Yoplait France, 92641 Boulogne-Billancourt, France.
| | - Laurence Vico
- INSERM U1059/LBTO, Université Jean Monnet, Université de Lyon, 42023 Saint-Étienne, France
| | - Norbert Laroche
- INSERM U1059/LBTO, Université Jean Monnet, Université de Lyon, 42023 Saint-Étienne, France
| | | | | | - François Blachier
- UMR 914 INRA-AgroParisTech, Nutrition Physiology and Ingestive Behavior, 75005 Paris, France
| | - Daniel Tomé
- UMR 914 INRA-AgroParisTech, Nutrition Physiology and Ingestive Behavior, 75005 Paris, France
| | - Anne Blais
- UMR 914 INRA-AgroParisTech, Nutrition Physiology and Ingestive Behavior, 75005 Paris, France
| |
Collapse
|
33
|
Conigrave AD, Ward DT. Calcium-sensing receptor (CaSR): pharmacological properties and signaling pathways. Best Pract Res Clin Endocrinol Metab 2013; 27:315-31. [PMID: 23856262 DOI: 10.1016/j.beem.2013.05.010] [Citation(s) in RCA: 151] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
In this article we consider the mechanisms by which the calcium-sensing receptor (CaSR) induces its cellular responses via the control (activation or inhibition) of signaling pathways. We consider key features of CaSR-mediated signaling including its control of the heterotrimeric G-proteins Gq/11, Gi/o and G12/13 and the downstream consequences recognizing that very few CaSR-mediated cell phenomena have been fully described. We also consider the manner in which the CaSR contributes to the formation of specific signaling scaffolds via peptide recognition sequences in its intracellular C-terminal along with the origins of its high level of cooperativity, particularly for Ca(2+)o, and its remarkable resistance to desensitization. We also consider the nature of the mechanisms by which the CaSR controls oscillatory and sustained Ca(2+)i mobilizing responses and inhibits or elevates cyclic adenosine monophosphate (cAMP) levels dependent on the cellular and signaling context. Finally, we consider the diversity of the receptor's ligands, ligand binding sites and broader compartment-dependent physiological roles leading to the identification of pronounced ligand-biased signaling for agonists including Sr(2+) and modulators including l-amino acids and the clinically effective calcimimetic cinacalcet. We note the implications of these findings for the development of new designer drugs that might target the CaSR in pathophysiological contexts beyond those established for the treatment of disorders of calcium metabolism.
Collapse
Affiliation(s)
- Arthur D Conigrave
- School of Molecular Bioscience, University of Sydney, NSW 2006, Australia.
| | | |
Collapse
|
34
|
Avlani VA, Ma W, Mun HC, Leach K, Delbridge L, Christopoulos A, Conigrave AD. Calcium-sensing receptor-dependent activation of CREB phosphorylation in HEK293 cells and human parathyroid cells. Am J Physiol Endocrinol Metab 2013; 304:E1097-104. [PMID: 23531616 DOI: 10.1152/ajpendo.00054.2013] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In addition to its acute effects on hormone secretion, epithelial transport, and shape change, the calcium-sensing receptor (CaSR) modulates the expression of genes that control cell survival, proliferation, and differentiation as well as the synthesis of peptide hormones and enzymes. In the present study, we investigated the impacts of a CaSR agonist and several CaSR modulators on phosphorylation of transcription factor CREB residue Ser(133) in CaSR-expressing HEK293 (HEK-CaSR) cells and human adenomatous parathyroid cells. Elevated Ca(2+)o concentration had no effect on CREB phosphorylation (p-CREB) in control HEK293 cells but stimulated p-CREB in both HEK-CaSR cells and human parathyroid cells. In addition, p-CREB was stimulated by the positive modulator cinacalcet and inhibited by the negative modulator NPS 2143 in both CaSR-expressing cell types. Two positive modulators that bind in the receptor's Venus Fly Trap domain, l-phenylalanine and S-methylglutathione, had no effect on p-CREB in HEK-CaSR cells, demonstrating the existence of pronounced signaling bias. Analysis of the signaling pathways using specific inhibitors demonstrated that phosphoinositide-specific phospholipase C and conventional protein kinase C isoforms make major contributions to Ca(2+)o-induced p-CREB in both cell-types, suggesting key roles for Gq/11. In addition, in parathyroid cells but not HEK-CaSR cells, activation of p-CREB was dependent on Gi/o, demonstrating the existence of cell type-specific signaling.
Collapse
Affiliation(s)
- Vimesh A Avlani
- School of Molecular Bioscience, University of Sydney, Sydney, New South Wales, Australia
| | | | | | | | | | | | | |
Collapse
|
35
|
Tonack S, Tang C, Offermanns S. Endogenous metabolites as ligands for G protein-coupled receptors modulating risk factors for metabolic and cardiovascular disease. Am J Physiol Heart Circ Physiol 2012; 304:H501-13. [PMID: 23241321 DOI: 10.1152/ajpheart.00641.2012] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
During the last decade, several G protein-coupled receptors activated by endogenous metabolites have been described. These receptors respond to fatty acids, mono- and disaccharides, amino acids, or various intermediates and products of metabolism, including ketone bodies, lactate, succinate, or bile acids. Receptors of endogenous metabolites are expressed in taste cells, the gastrointestinal tract, adipose tissue, endocrine glands, immune cells, or the kidney and are therefore in a position to sense food intake in the gastrointestinal tract or to link metabolite levels to the appropriate responses of metabolic organs. Some of the receptors appear to provide a link between metabolic and neuronal or immune functions. Given that many of these metabolic processes are dysregulated under pathological conditions, including diabetes, dyslipidemia, and obesity, receptors of endogenous metabolites have also been recognized as potential drug targets to prevent and/or treat metabolic and cardiovascular diseases. This review describes G protein-coupled receptors activated by endogenous metabolites and summarizes their physiological, pathophysiological, and potential pharmacological roles.
Collapse
Affiliation(s)
- Sarah Tonack
- Department of Pharmacology, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
| | | | | |
Collapse
|
36
|
Invernizzi M, Carda S, Righini V, Baricich A, Cisari C, Bevilacqua M. Different PTH response to oral peptone load and oral calcium load in patients with normocalcemic primary hyperparathyroidism, primary hyperparathyroidism, and healthy subjects. Eur J Endocrinol 2012; 167:491-7. [PMID: 22872468 DOI: 10.1530/eje-12-0362] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
BACKGROUND Normocalcemic primary hyperparathyroidism (PHPT-N) is a condition that may have similar long-term implications to primary hyperparathyroidism (PHPT); however, differential diagnosis and treatment for parathyroid disorders are not clearly defined. We investigated the effect of an oral peptone and an oral calcium load on calcium-regulating hormones in PHPT-N compared with PHPT and healthy controls to provide a new potential diagnostic tool. DESIGN Case-control study. METHODS We evaluated serum gastrin, PTH, ionized calcium, and phosphate responses to oral calcium (1 g) and peptone (10 g) load in 22 PHPT and 20 PHPT-N patients matched for PTH serum values. Moreover, 30 healthy subjects were enrolled as controls. In 12 patients for each group, we also performed the oral peptone test adding aluminum hydroxide (AH) to suppress phosphate absorption. RESULTS In PHPT patients, PTH increased significantly 30 min after the oral peptone load, while no significant increase was found in PHPT-N and controls. After oral calcium load, PTH remained stable in PHPT while it decreased dramatically in PHPT-N patients, and ionized calcium increased significantly in each of the three groups. Peptones plus AH induced a blunted PTH increase in the three groups. CONCLUSIONS Considering the marked difference in PTH response elicited by peptones in PHPT compared with PHPT-N, we suggest that the oral peptone test could be added to the diagnostic evaluation of PHPT patients. In case of absent response to peptones, patients should have their serum calcium levels assessed twice a year in accordance with recent guidelines.
Collapse
Affiliation(s)
- Marco Invernizzi
- Physical and Rehabilitation Medicine, Department of Health Sciences, University of Eastern Piedmont A. Avogadro, AOU Maggiore della Carità, Viale Piazza D'armi 1, 28100 Novara, Italy.
| | | | | | | | | | | |
Collapse
|
37
|
Abstract
Recent advances highlight that nutrient receptors (such as T1R1/T1R3 heterodimer, Ca sensing receptor and GPR93 for amino acids and protein, GPR40, GPR41, GPR43 and GPR120 for fatty acids, T1R2/T1R3 heterodimer for monosaccharides) are expressed in the apical face of the gut and sense nutrients in the lumen. They transduce signals for the regulation of nutrient transporter expressions in the apical face. Interestingly, they are also localised in enteroendocrine cells (EEC) and mainly exert a direct control on the secretion in the lamina propria of gastro-intestinal peptides such as cholecystokinin, glucagon-like peptide-1 and peptide YY in response to energy nutrient transit and absorption in the gut. This informs central nuclei involved in the control of feeding such as the hypothalamus and nucleus of the solitary tract of the availability of these nutrients and thus triggers adaptive responses to maintain energy homoeostasis. These nutrient receptors then have a prominent position since they manage nutrient absorption and are principally the generator of the first signal of satiation mechanisms mainly transmitted to the brain by vagal afferents. Moreover, tastants are also able to elicit gut peptides secretion via chemosensory receptors expressed in EEC. Targeting these nutrient and tastant receptors in EEC may thus be helpful to promote satiation and so to fight overfeeding and its consequences.
Collapse
|
38
|
Smajilovic S, Yano S, Jabbari R, Tfelt-Hansen J. The calcium-sensing receptor and calcimimetics in blood pressure modulation. Br J Pharmacol 2012; 164:884-93. [PMID: 21410453 DOI: 10.1111/j.1476-5381.2011.01317.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Calcium is a crucial second messenger in the cardiovascular system. However, calcium may also be an extracellular first messenger through a G-protein-coupled receptor that senses extracellular concentration (Ca(2+)(o)), the calcium-sensing receptor (CaR). The most prominent physiological function of the CaR is to maintain the extracellular Ca(2+) level in a very tight range by regulating the circulating levels of parathyroid hormone (PTH). This control over PTH and Ca(2+) levels is partially lost in patients suffering from primary and secondary hyperparathyroidism. Allosteric modulators of the CaR (calcimimetics) are the first drugs in their class to become available for clinical use and have been shown to successfully treat certain forms of primary and secondary hyperparathyroidism. In addition, several studies suggest beneficial effects of calcimimetics on cardiovascular risk factors associated with hyperparathyroidism. Although a plethora of studies demonstrated the CaR in heart and blood vessels, exact roles of the receptor in the cardiovascular system still remain to be elucidated. However, several studies point toward a possibility that the CaR might be involved in the regulation of vascular tone. This review will summarize the current knowledge on the possible functions of the CaR and calcimimetics on blood pressure regulation.
Collapse
Affiliation(s)
- Sanela Smajilovic
- Laboratory of Molecular Cardiology, Department of Cardiology, Copenhagen University Hospital, Denmark
| | | | | | | |
Collapse
|
39
|
Riccardi D, Kemp PJ. The Calcium-Sensing Receptor Beyond Extracellular Calcium Homeostasis: Conception, Development, Adult Physiology, and Disease. Annu Rev Physiol 2012; 74:271-97. [DOI: 10.1146/annurev-physiol-020911-153318] [Citation(s) in RCA: 111] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Daniela Riccardi
- Division of Pathophysiology and Repair, School of Biosciences, Cardiff University, Cardiff, CF10 3AX, United Kingdom; ,
| | - Paul J. Kemp
- Division of Pathophysiology and Repair, School of Biosciences, Cardiff University, Cardiff, CF10 3AX, United Kingdom; ,
| |
Collapse
|
40
|
Karohl C, Raggi P. Cinacalcet: will it play a role in reducing cardiovascular events? Future Cardiol 2012; 8:357-70. [PMID: 22420327 DOI: 10.2217/fca.11.82] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Secondary hyperparathyroidism is a common complication of chronic kidney disease and it is associated with high morbidity and mortality. It is characterized by high parathyroid hormone levels and bone turnover leading to bone pain, deformity and fragility. Furthermore, secondary hyperparathyroidism adversely affects the cardiovascular system and has been associated with cardiovascular calcification and cardiomyopathy. Cinacalcet, a type II calcimimetic, is an effective and well-tolerated oral therapy for the management of secondary hyperparathyroidism. It is an allosteric activator of the calcium-sensing receptor enhancing sensitivity of parathyroid cells to extracellular calcium, which leads to inhibition of parathyroid hormone secretion. The calcium-sensing receptor expression in cardiomyocytes, endothelial cells and vascular smooth muscle cells raises the possibility that this receptor may be implicated in the pathophysiology of cardiovascular disease and constitute a potential therapeutic target. This article reviews the role of the calcimimetic agent cinacalcet in the prevention and progression of cardiovascular calcification and uremic cardiomyopathy in the chronic kidney disease setting.
Collapse
Affiliation(s)
- Cristina Karohl
- Division of Cardiology & Department of Medicine, Emory University, 1365 Clifton Rd NE, AT-504, Atlanta, GA 30322, USA
| | | |
Collapse
|
41
|
Abstract
The calcium-sensing receptor (CaR) is the key controller of extracellular calcium (Ca(2+)(o)) homeostasis via its regulation of parathyroid hormone (PTH) secretion and renal Ca(2+) reabsorption. The CaR-selective calcimimetic drug Cinacalcet stimulates the CaR to suppress PTH secretion in chronic kidney disease and represents the world's first clinically available receptor positive allosteric modulator (PAM). Negative CaR allosteric modulators (NAMs), known as calcilytics, can increase PTH secretion and are being investigated as possible bone anabolic treatments against age-related osteoporosis. Here we address the current state of development and clinical use of a series of positive and negative CaR modulators. In addition, clinical CaR mutations and transgenic mice carrying tissue-specific CaR deletions have provided a novel understanding of the relative functional importance of CaR in both calciotropic tissues and those elsewhere in the body. The development of CaR-selective modulators and signalling reagents have provided us with a more detailed appreciation of how the CaR signals in vivo. Thus, both of these areas of CaR research will be reviewed.
Collapse
Affiliation(s)
- Donald T Ward
- Faculty of Life Sciences, The University of ManchesterManchester, UK
| | | |
Collapse
|
42
|
Weston AH, Geraghty A, Egner I, Edwards G. The vascular extracellular calcium-sensing receptor: an update. Acta Physiol (Oxf) 2011; 203:127-37. [PMID: 21199402 DOI: 10.1111/j.1748-1716.2010.02249.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
The extracellular calcium-sensing receptor (CaR) was first described in the parathyroid gland. Recent studies have shown that the CaR is also expressed in blood vessels, especially in the endothelial and adventitial layers but its physiological function is still not clear. However, an understanding of its possible role(s) in the vasculature (perivascular-neurones, heart and blood vessels) is important because of the use of synthetic positive allosteric CaR modulators in hyperparathyroidism and the potential importance of negative modulators in the treatment of osteoporosis. In this review, the effects of CaR activation and inhibition are detailed and the possible role of the CaR as both an amplifier and attenuator of myo-endothelial coupling in the vasculature is described.
Collapse
Affiliation(s)
- A H Weston
- Faculty of Life Sciences, University of Manchester, UK
| | | | | | | |
Collapse
|
43
|
Abstract
In goats, the combination of dietary N and Ca reduction caused hypocalcaemia and further changes in Ca homeostasis. The aim of the present study was to characterise the effects of dietary N reduction under normocalcaemia on mineral and bone metabolism in young goats. Young male goats of the Saanen breed were fed a diet reduced in N (8 %) for about 7 weeks (ten animals per group) and were compared with goats fed with an adequate N (14 %) diet. When N intake was reduced in young goats, plasma urea concentrations as well as renal elimination of urea were reduced. This was inversely related to creatinine in plasma and urine, which increased during a dietary N reduction as a function of reduced renal activity to save urea during N scarcity. During this decrease in renal function, associated with declined insulin-like growth factor 1 concentrations, a reduction in calcidiol and calcitriol concentrations could be observed. Meanwhile, carboxyterminal cross-linked telopeptide of type I collagen values and activity of total alkaline phosphatase were both elevated, indicating some bone remodelling processes taking place during a reduced N diet in young goats. The concentrations of inorganic phosphate (Pi) and total Ca were changed in several body fluids, indicating that Pi and Ca homeostasis was perturbed in goats fed a reduced N diet. Therefore, more research is needed to find the balance between reduction of environmental N pollution by reducing dietary N in ruminant feeding and maintaining the animal's health.
Collapse
|
44
|
|
45
|
Urwyler S. Allosteric modulation of family C G-protein-coupled receptors: from molecular insights to therapeutic perspectives. Pharmacol Rev 2011; 63:59-126. [PMID: 21228259 DOI: 10.1124/pr.109.002501] [Citation(s) in RCA: 164] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Allosteric receptor modulation is an attractive concept in drug targeting because it offers important potential advantages over conventional orthosteric agonism or antagonism. Allosteric ligands modulate receptor function by binding to a site distinct from the recognition site for the endogenous agonist. They often have no effect on their own and therefore act only in conjunction with physiological receptor activation. This article reviews the current status of allosteric modulation at family C G-protein coupled receptors in the light of their specific structural features on the one hand and current concepts in receptor theory on the other hand. Family C G-protein-coupled receptors are characterized by a large extracellular domain containing the orthosteric agonist binding site known as the "venus flytrap module" because of its bilobal structure and the dynamics of its activation mechanism. Mutational analysis and chimeric constructs have revealed that allosteric modulators of the calcium-sensing, metabotropic glutamate and GABA(B) receptors bind to the seven transmembrane domain, through which they modify signal transduction after receptor activation. This is in contrast to taste-enhancing molecules, which bind to different parts of sweet and umami receptors. The complexity of interactions between orthosteric and allosteric ligands is revealed by a number of adequate biochemical and electrophysiological assay systems. Many allosteric family C GPCR modulators show in vivo efficacy in behavioral models for a variety of clinical indications. The positive allosteric calcium sensing receptor modulator cinacalcet is the first drug of this type to enter the market and therefore provides proof of principle in humans.
Collapse
Affiliation(s)
- Stephan Urwyler
- Department of Chemistry and Biochemistry, University of Berne, P/A Weissensteinweg 3, CH-3303 Jegenstorf, Berne, Switzerland.
| |
Collapse
|
46
|
Broadhead GK, Mun HC, Avlani VA, Jourdon O, Church WB, Christopoulos A, Delbridge L, Conigrave AD. Allosteric modulation of the calcium-sensing receptor by gamma-glutamyl peptides: inhibition of PTH secretion, suppression of intracellular cAMP levels, and a common mechanism of action with L-amino acids. J Biol Chem 2010; 286:8786-97. [PMID: 21187282 DOI: 10.1074/jbc.m110.149724] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
γ-Glutamyl peptides were identified previously as novel positive allosteric modulators of Ca(2+)(o)-dependent intracellular Ca(2+) mobilization in HEK-293 cells that bind in the calcium-sensing receptor VFT domain. In the current study, we investigated whether γ-glutamyl-tripeptides including γ-Glu-Cys-Gly (glutathione) and its analogs S-methylglutathione and S-propylglutathione, or dipeptides including γ-Glu-Ala and γ-Glu-Cys are positive allosteric modulators of Ca(2+)(o)-dependent Ca(2+)(i) mobilization and PTH secretion from normal human parathyroid cells as well as Ca(2+)(o)-dependent suppression of intracellular cAMP levels in calcium-sensing receptor (CaR)-expressing HEK-293 cells. In addition, we compared the effects of the potent γ-glutamyl peptide S-methylglutathione, and the amino acid L-Phe on HEK-293 cells that stably expressed either the wild-type CaR or the double mutant T145A/S170T, which exhibits selectively impaired responses to L-amino acids. We find that γ-glutamyl peptides are potent positive allosteric modulators of the CaR that promote Ca(2+)(o)-dependent Ca(2+)(i) mobilization, suppress intracellular cAMP levels and inhibit PTH secretion from normal human parathyroid cells. Furthermore, we find that the double mutant T145A/S170T exhibits markedly impaired Ca(2+)(i) mobilization and cAMP suppression responses to S-methylglutathione as well as L-Phe indicating that γ-glutamyl peptides and L-amino acids activate the CaR via a common mechanism.
Collapse
Affiliation(s)
- Geoffrey K Broadhead
- School of Molecular Bioscience, University of Sydney, New South Wales 2006, Australia
| | | | | | | | | | | | | | | |
Collapse
|
47
|
Calcium-sensing receptor is a physiologic multimodal chemosensor regulating gastric G-cell growth and gastrin secretion. Proc Natl Acad Sci U S A 2010; 107:17791-6. [PMID: 20876097 DOI: 10.1073/pnas.1009078107] [Citation(s) in RCA: 106] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The calcium-sensing receptor (CaR) is the major sensor and regulator of extracellular Ca(2+), whose activity is allosterically regulated by amino acids and pH. Recently, CaR has been identified in the stomach and intestinal tract, where it has been proposed to function in a non-Ca(2+) homeostatic capacity. Luminal nutrients, such as Ca(2+) and amino acids, have been recognized for decades as potent stimulants for gastrin and acid secretion, although the molecular basis for their recognition remains unknown. The expression of CaR on gastrin-secreting G cells in the stomach and their shared activation by Ca(2+), amino acids, and elevated pH suggest that CaR may function as the elusive physiologic sensor regulating gastrin and acid secretion. The genetic and pharmacologic studies presented here comparing CaR-null mice and wild-type littermates support this hypothesis. Gavage of Ca(2+), peptone, phenylalanine, Hepes buffer (pH 7.4), and CaR-specific calcimimetic, cinacalcet, stimulated gastrin and acid secretion, whereas the calcilytic, NPS 2143, inhibited secretion only in the wild-type mouse. Consistent with known growth and developmental functions of CaR, G-cell number was progressively reduced between 30 and 90 d of age by more than 65% in CaR-null mice. These studies of nutrient-regulated G-cell gastrin secretion and growth provide definitive evidence that CaR functions as a physiologically relevant multimodal sensor. Medicinals targeting diseases of Ca(2+) homeostasis should be reviewed for effects outside traditional Ca(2+)-regulating tissues in view of the broader distribution and function of CaR.
Collapse
|
48
|
Muscher A, Huber K. Effects of a reduced nitrogen diet on calcitriol levels and calcium metabolism in growing goats. J Steroid Biochem Mol Biol 2010; 121:304-7. [PMID: 20399271 DOI: 10.1016/j.jsbmb.2010.03.084] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/03/2009] [Revised: 03/24/2010] [Accepted: 03/26/2010] [Indexed: 11/17/2022]
Abstract
For monogastric animals, changes in dietary protein content modulate calcium (Ca) metabolism by changing parathyroid hormone and calcitriol concentrations. However, the effects of dietary nitrogen (N) restriction on Ca metabolism are not known in ruminants. Since ruminants express endogenous recycling mechanisms very efficiently to save N, it is known that these recycling mechanisms protect ruminants against N depletion in times of dietary N restriction. Therefore, consequences on Ca metabolism induced by reduction of dietary N supply as observed in monogastric animals should not occur in ruminants. Due to this specific metabolic feature, a reduction of dietary N intake can be used to diminish environmental N pollution. The aim of the present study was to determine the consequences of a reduced N intake on Ca homeostasis and respective regulatory hormone concentrations in ruminants. Growing goats fed with a reduced N diet showed a decrease in ionised calcium (Ca2+) and total Ca concentrations while bone resorption marker carboxyterminal cross-linked telopeptide of type I collagen increased in plasma. Unexpectedly, despite hypocalcemia, concentrations of calcitriol were decreased in the animals of the N reduction group whereas calcidiol levels were not affected. From this data, it can be concluded that the Ca metabolism of growing goats can be modulated by changes of dietary N content like in monogastric animals.
Collapse
Affiliation(s)
- Alexandra Muscher
- Department of Physiology, University of Veterinary Medicine Hannover, Bischofsholer Damm 15/102, 30173 Hannover, Germany.
| | | |
Collapse
|
49
|
Jensen AA, Bräuner-Osborne H. Allosteric modulation of the calcium-sensing receptor. Curr Neuropharmacol 2010; 5:180-6. [PMID: 19305800 PMCID: PMC2656812 DOI: 10.2174/157015907781695982] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2007] [Accepted: 04/05/2007] [Indexed: 12/20/2022] Open
Abstract
The calcium (Ca2+)-sensing receptor (CaR) belongs to family C of the G-protein coupled receptors (GPCRs). The receptor is activated by physiological levels of Ca2+ (and Mg2+) and positively modulated by a range of proteinogenic L-α-amino acids. Recently, several synthetic allosteric modulators of the receptor have been developed, which either act as positive modulators (termed calcimimetics) or negative modulators (termed calcilytics). These ligands do not activate the wild-type receptor directly, but rather shift the concentration-response curves of Ca2+ to the left or right, respectively. Like other family C GPCRs, the CaR contains a large amino-terminal domain and a 7-transmembrane domain. Whereas the endogenous ligands for the receptor, Ca2+, Mg2+ and the L-α-amino acids, bind to the amino-terminal domain, most if not all of the synthetic modulators published so far bind to the 7-transmembrane domain. The most prominent physiological function of the CaR is to maintain the extracellular Ca2+ level in a very tight range via control of secretion of parathyroid hormone (PTH). Influence on e.g. secretion of calcitonin from thyroid C-cells and direct action on the tubule of the kidney also contribute to the control of the extracellular Ca2+ level. This control over PTH and Ca2+ levels is partially lost in patients suffering from primary and secondary hyperparathyroidism. The perspectives in CaR as a therapeutic target have been underlined by the recent approval of the calcimimetic cinacalcet for the treatment of certain forms of primary and secondary hyperparathyroidism. Cinacalcet is the first clinically administered allosteric modulator acting on a GPCR, and thus the compound constitutes an important proof-of-concept for future development of allosteric modulators on other GPCR drug targets.
Collapse
Affiliation(s)
- Anders A Jensen
- Department of Medicinal Chemistry, Faculty of Pharmaceutical Sciences, University of Copenhagen, Universitetsparken 2, 2100 Copenhagen, Denmark
| | | |
Collapse
|
50
|
McCormick WD, Atkinson-Dell R, Campion KL, Mun HC, Conigrave AD, Ward DT. Increased receptor stimulation elicits differential calcium-sensing receptor(T888) dephosphorylation. J Biol Chem 2010; 285:14170-7. [PMID: 20233724 DOI: 10.1074/jbc.m109.071084] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The calcium-sensing receptor (CaR) elicits oscillatory Ca(2+)(i) mobilization associated with dynamic, inhibitory protein kinase C-mediated phosphorylation of CaR(T888). While modest CaR stimulation elicits Ca(2+)(i) oscillations, greater stimulation either increases oscillation frequency or elicits sustained responses by an unknown mechanism. Here, moderate CaR stimulation (2.5 mm Ca(2+)(o), 10 min) increased CaR(T888) phosphorylation (160-kDa mature receptor) 5-fold in CaR stably transfected HEK-293 cells, whereas 3-5 mm Ca(2+)(o) treatments were without apparent effect. Treatment with 2 mm Ca(2+)(o) caused sustained CaR(T888) phosphorylation (> or = 20 min) and oscillatory Ca(2+)(i) mobilization. However, 5 mm Ca(2+)(o) increased CaR(T888) phosphorylation only briefly while eliciting sustained Ca(2+)(i) mobilization, suggesting that greater CaR activation induces rapid CaR(T888) dephosphorylation, thus permitting sustained Ca(2+)(i) responses. Indeed, 5 mm Ca(2+)(o) stimulated protein phosphatase 2A activity and induced CaR(T888) dephosphorylation following acute phorbol ester pretreatment, the latter effect being mimicked by CaR-positive allosteric modulators (NPS-R467 and l-Phe). Finally, the phosphatase inhibitor calyculin-A reversed CaR-induced inhibition of parathyroid hormone secretion from bovine parathyroid slices and normal human parathyroid cells, demonstrating the physiological importance of phosphorylation status on parathyroid function. Therefore, high Ca(2+)(o)-stimulated protein kinase C acts in concert with high Ca(2+)(o)-induced phosphatase activity to generate and maintain CaR-induced Ca(2+)(i) oscillations via the dynamic phosphorylation and dephosphorylation of CaR(T888).
Collapse
Affiliation(s)
- Wanda D McCormick
- Faculty of Life Sciences, The University of Manchester, Manchester M13 9NT, United Kingdom
| | | | | | | | | | | |
Collapse
|