51
|
Dong B, Endo I, Ohnishi Y, Kondo T, Hasegawa T, Amizuka N, Kiyonari H, Shioi G, Abe M, Fukumoto S, Matsumoto T. Calcilytic Ameliorates Abnormalities of Mutant Calcium-Sensing Receptor (CaSR) Knock-In Mice Mimicking Autosomal Dominant Hypocalcemia (ADH). J Bone Miner Res 2015; 30:1980-93. [PMID: 25967373 DOI: 10.1002/jbmr.2551] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/17/2015] [Revised: 04/16/2015] [Accepted: 05/07/2015] [Indexed: 02/01/2023]
Abstract
Activating mutations of calcium-sensing receptor (CaSR) cause autosomal dominant hypocalcemia (ADH). ADH patients develop hypocalcemia, hyperphosphatemia, and hypercalciuria, similar to the clinical features of hypoparathyroidism. The current treatment of ADH is similar to the other forms of hypoparathyroidism, using active vitamin D3 or parathyroid hormone (PTH). However, these treatments aggravate hypercalciuria and renal calcification. Thus, new therapeutic strategies for ADH are needed. Calcilytics are allosteric antagonists of CaSR, and may be effective for the treatment of ADH caused by activating mutations of CaSR. In order to examine the effect of calcilytic JTT-305/MK-5442 on CaSR harboring activating mutations in the extracellular and transmembrane domains in vitro, we first transfected a mutated CaSR gene into HEK cells. JTT-305/MK-5442 suppressed the hypersensitivity to extracellular Ca(2+) of HEK cells transfected with the CaSR gene with activating mutations in the extracellular and transmembrane domains. We then selected two activating mutations locating in the extracellular (C129S) and transmembrane (A843E) domains, and generated two strains of CaSR knock-in mice to build an ADH mouse model. Both mutant mice mimicked almost all the clinical features of human ADH. JTT-305/MK-5442 treatment in vivo increased urinary cAMP excretion, improved serum and urinary calcium and phosphate levels by stimulating endogenous PTH secretion, and prevented renal calcification. In contrast, PTH(1-34) treatment normalized serum calcium and phosphate but could not reduce hypercalciuria or renal calcification. CaSR knock-in mice exhibited low bone turnover due to the deficiency of PTH, and JTT-305/MK-5442 as well as PTH(1-34) increased bone turnover and bone mineral density (BMD) in these mice. These results demonstrate that calcilytics can reverse almost all the phenotypes of ADH including hypercalciuria and renal calcification, and suggest that calcilytics can become a novel therapeutic agent for ADH.
Collapse
Affiliation(s)
- Bingzi Dong
- Department of Medicine and Bioregulatory Sciences, University of Tokushima Graduate School of Medical Sciences, Tokushima, Japan
| | - Itsuro Endo
- Department of Medicine and Bioregulatory Sciences, University of Tokushima Graduate School of Medical Sciences, Tokushima, Japan
| | - Yukiyo Ohnishi
- Department of Medicine and Bioregulatory Sciences, University of Tokushima Graduate School of Medical Sciences, Tokushima, Japan
| | - Takeshi Kondo
- Department of Medicine and Bioregulatory Sciences, University of Tokushima Graduate School of Medical Sciences, Tokushima, Japan
| | - Tomoka Hasegawa
- Department of Developmental Biology of Hard Tissue, Hokkaido University Graduate School of Dental Medicine, Sapporo, Japan
| | - Norio Amizuka
- Department of Developmental Biology of Hard Tissue, Hokkaido University Graduate School of Dental Medicine, Sapporo, Japan
| | - Hiroshi Kiyonari
- Animal Resource Development Unit, RIKEN Center for Life Science Technologies, Kobe, Japan
| | - Go Shioi
- Genetic Engineering Team, RIKEN Center for Life Science Technologies, Kobe, Japan
| | - Masahiro Abe
- Department of Medicine and Bioregulatory Sciences, University of Tokushima Graduate School of Medical Sciences, Tokushima, Japan
| | - Seiji Fukumoto
- Fujii Memorial Institute of Medical Sciences, Tokushima University, Tokushima, Japan
| | - Toshio Matsumoto
- Fujii Memorial Institute of Medical Sciences, Tokushima University, Tokushima, Japan
| |
Collapse
|
52
|
Lee S, Mannstadt M, Guo J, Kim SM, Yi HS, Khatri A, Dean T, Okazaki M, Gardella TJ, Jüppner H. A Homozygous [Cys25]PTH(1-84) Mutation That Impairs PTH/PTHrP Receptor Activation Defines a Novel Form of Hypoparathyroidism. J Bone Miner Res 2015; 30:1803-13. [PMID: 25891861 PMCID: PMC4580526 DOI: 10.1002/jbmr.2532] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Revised: 03/30/2015] [Accepted: 04/13/2015] [Indexed: 11/10/2022]
Abstract
Hypocalcemia and hyperphosphatemia are encountered in idiopathic hypoparathyroidism (IHP) and pseudohypoparathyroidism type Ib (PHP1B). In contrast to PHP1B, which is caused by resistance toward parathyroid hormone (PTH), the genetic defects leading to IHP impair production of this important regulator of mineral ion homeostasis. So far, only five PTH mutations were shown to cause IHP, each of which is located in the hormone's pre-pro leader segment and thus impair hormone secretion. In three siblings affected by IHP, we now identified a homozygous arginine-to-cysteine mutation at position 25 (R25C) of the mature PTH(1-84) polypeptide; heterozygous family members are healthy. Depending on the assay used for evaluating these patients, plasma PTH levels were either low or profoundly elevated, thus leading to ambiguities regarding the underlying diagnosis, namely IHP or PHP1B. Consistent with increased PTH levels, recombinant [Cys25]PTH(1-84) and wild-type PTH(1-84) were secreted equally well by transfected COS-7 cells. However, synthetic [Cys25]PTH(1-34) was found to have a lower binding affinity for the PTH receptor type-1 (PTH1R) than PTH(1-34) and consequently a lower efficiency for stimulating cAMP formation in cells expressing this receptor. Consistent with these in vitro findings, long-term infusion of [Cys25]PTH(1-34) resulted only in minimal calcemic and phosphaturic responses, despite readily detectable levels of [Cys25]PTH(1-34) in plasma. The mineral ion abnormalities observed in the three IHP patients are thus most likely caused by the inherited homozygous missense PTH mutation, which reduces bioactivity of the secreted hormone. Based on these findings, screening for PTH(1-84) mutations should be considered when clinical and laboratory findings are consistent with PHP1B, but GNAS methylation changes have been excluded. Differentiating between IHP and PHP1B has considerable implications for genetic counseling, therapy, and long-term outcome because treatment of IHP patients with inappropriately high doses of active vitamin D and calcium can contribute to development of nephrocalcinosis and chronic kidney disease.
Collapse
Affiliation(s)
- Sihoon Lee
- Department of Internal Medicine and Laboratory of Molecular Endocrinology, Gachon University School of Medicine, Incheon, South Korea
| | - Michael Mannstadt
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Jun Guo
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Seul Min Kim
- Department of Internal Medicine and Laboratory of Molecular Endocrinology, Gachon University School of Medicine, Incheon, South Korea
| | - Hyon-Seung Yi
- Department of Internal Medicine and Laboratory of Molecular Endocrinology, Gachon University School of Medicine, Incheon, South Korea
| | - Ashok Khatri
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Thomas Dean
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Makoto Okazaki
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Thomas J Gardella
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Harald Jüppner
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA.,Pediatric Nephrology Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| |
Collapse
|
53
|
Flock T, Ravarani CNJ, Sun D, Venkatakrishnan AJ, Kayikci M, Tate CG, Veprintsev DB, Babu MM. Universal allosteric mechanism for Gα activation by GPCRs. Nature 2015; 524:173-179. [PMID: 26147082 PMCID: PMC4866443 DOI: 10.1038/nature14663] [Citation(s) in RCA: 252] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2014] [Accepted: 06/16/2015] [Indexed: 12/25/2022]
Abstract
G protein-coupled receptors (GPCRs) allosterically activate heterotrimeric G proteins and trigger GDP release. Given that there are ∼800 human GPCRs and 16 different Gα genes, this raises the question of whether a universal allosteric mechanism governs Gα activation. Here we show that different GPCRs interact with and activate Gα proteins through a highly conserved mechanism. Comparison of Gα with the small G protein Ras reveals how the evolution of short segments that undergo disorder-to-order transitions can decouple regions important for allosteric activation from receptor binding specificity. This might explain how the GPCR-Gα system diversified rapidly, while conserving the allosteric activation mechanism.
Collapse
Affiliation(s)
- Tilman Flock
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK
| | | | - Dawei Sun
- Laboratory of Biomolecular Research, Paul Scherrer Institut, Villigen, Switzerland
- Department of Biology, ETH Zurich, Zurich, Switzerland
| | | | - Melis Kayikci
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK
| | - Christopher G. Tate
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK
| | - Dmitry B. Veprintsev
- Laboratory of Biomolecular Research, Paul Scherrer Institut, Villigen, Switzerland
- Department of Biology, ETH Zurich, Zurich, Switzerland
| | - M. Madan Babu
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK
| |
Collapse
|
54
|
Duan K, Gomez Hernandez K, Mete O. Clinicopathological correlates of hyperparathyroidism. J Clin Pathol 2015; 68:771-87. [PMID: 26163537 DOI: 10.1136/jclinpath-2015-203186] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Accepted: 06/20/2015] [Indexed: 12/21/2022]
Abstract
Hyperparathyroidism is a common endocrine disorder with potential complications on the skeletal, renal, neurocognitive and cardiovascular systems. While most cases (95%) occur sporadically, about 5% are associated with a hereditary syndrome: multiple endocrine neoplasia syndromes (MEN-1, MEN-2A, MEN-4), hyperparathyroidism-jaw tumour syndrome (HPT-JT), familial hypocalciuric hypercalcaemia (FHH-1, FHH-2, FHH-3), familial hypercalciuric hypercalcaemia, neonatal severe hyperparathyroidism and isolated familial hyperparathyroidism. Recently, molecular mechanisms underlying possible tumour suppressor genes (MEN1, CDC73/HRPT2, CDKIs, APC, SFRPs, GSK3β, RASSF1A, HIC1, RIZ1, WT1, CaSR, GNA11, AP2S1) and proto-oncogenes (CCND1/PRAD1, RET, ZFX, CTNNB1, EZH2) have been uncovered in the pathogenesis of hyperparathyroidism. While bi-allelic inactivation of CDC73/HRPT2 seems unique to parathyroid malignancy, aberrant activation of cyclin D1 and Wnt/β-catenin signalling has been reported in benign and malignant parathyroid tumours. Clinicopathological correlates of primary hyperparathyroidism include parathyroid adenoma (80-85%), hyperplasia (10-15%) and carcinoma (<1-5%). Secondary hyperparathyroidism generally presents with diffuse parathyroid hyperplasia, whereas tertiary hyperparathyroidism reflects the emergence of autonomous parathyroid hormone (PTH)-producing neoplasm(s) from secondary parathyroid hyperplasia. Surgical resection of abnormal parathyroid tissue remains the only curative treatment in primary hyperparathyroidism, and parathyroidectomy specimens are frequently encountered in this setting. Clinical and biochemical features, including intraoperative PTH levels, number, weight and size of the affected parathyroid gland(s), are crucial parameters to consider when rendering an accurate diagnosis of parathyroid proliferations. This review provides an update on the expanding knowledge of hyperparathyroidism and highlights the clinicopathological correlations of this prevalent disease.
Collapse
Affiliation(s)
- Kai Duan
- Department of Pathology, University Health Network, Toronto, Ontario, Canada Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
| | - Karen Gomez Hernandez
- Endocrine Oncology Site Group, Princess Margaret Cancer Centre, Toronto, Ontario, Canada Department of Medicine, University Health Network, Toronto, Ontario, Canada
| | - Ozgur Mete
- Department of Pathology, University Health Network, Toronto, Ontario, Canada Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada Endocrine Oncology Site Group, Princess Margaret Cancer Centre, Toronto, Ontario, Canada
| |
Collapse
|
55
|
Rothenbuhler A, Linglart A. Treatment with rhPTH in children. ANNALES D'ENDOCRINOLOGIE 2015; 76:178-179. [PMID: 25910999 DOI: 10.1016/j.ando.2015.03.030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Affiliation(s)
- Anya Rothenbuhler
- Endocrinologie pédiatrique et centre de référence des maladies rares du métabolisme du calcium et du phosphore, hôpital Bicêtre, 78, rue du Général-Leclerc, 94270 Le Kremlin Bicêtre, France.
| | - Agnès Linglart
- Endocrinologie pédiatrique et centre de référence des maladies rares du métabolisme du calcium et du phosphore, hôpital Bicêtre, 78, rue du Général-Leclerc, 94270 Le Kremlin Bicêtre, France
| |
Collapse
|
56
|
Monis EL, Mannstadt M. Hypoparathyroidism - disease update and emerging treatments. ANNALES D'ENDOCRINOLOGIE 2015; 76:84-8. [PMID: 25882889 DOI: 10.1016/j.ando.2015.03.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Accepted: 03/17/2015] [Indexed: 01/21/2023]
Abstract
Parathyroid hormone (PTH) is the primary regulator of blood calcium levels and bone metabolism. Insufficient levels of PTH lead to hypoparathyroidism, characterized by low serum calcium and elevated serum phosphate levels. It is most commonly caused by the inadvertent damage to the parathyroid glands during thyroid surgery. Patients with hypoparathyroidism are currently being treated with oral calcium and active vitamin D, and to avoid worsening hypercalciuria, target serum calcium levels are within the lower end of normal. With current treatment, patients may suffer from large swings in serum calcium and are at a substantial risk of chronic renal failure, nephrocalcinosis, and kidney stones. The recent FDA approval of recombinant human (rh) PTH(1-84) for the treatment of hypoparathyroidism adds PTH replacement therapy to the endocrinologist's armamentarium to treat this chronic disease.
Collapse
Affiliation(s)
- Elizabeth L Monis
- Massachusetts General Hospital, Endocrine Unit, Thier 1051, 50 Blossom St, 02114 Boston, USA
| | - Michael Mannstadt
- Massachusetts General Hospital, Endocrine Unit, Thier 1051, 50 Blossom St, 02114 Boston, USA.
| |
Collapse
|
57
|
Eyal O, Oren A, Jüppner H, Somech R, De Bellis A, Mannstadt M, Szalat A, Bleiberg M, Weisman Y, Weintrob N. Hypoparathyroidism and central diabetes insipidus: in search of the link. Eur J Pediatr 2014; 173:1731-4. [PMID: 25367057 PMCID: PMC5103624 DOI: 10.1007/s00431-014-2448-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/09/2014] [Revised: 10/13/2014] [Accepted: 10/20/2014] [Indexed: 11/24/2022]
Abstract
UNLABELLED Two siblings (a 15-year-old boy and an 11-year-old girl) who presented with hypocalcemic seizure at the age of 2 years and 2 months (boy) and 2 years and 4 months (girl) were diagnosed with hypoparathyroidism. At the age of 3 years, the girl developed central diabetes insipidus with good response to desmopressin acetate treatment. The family history was unremarkable, and there was no consanguinity between the parents. The father is of Iraqi/Egyptian Jewish origin and the mother is of Iranian/Romanian Jewish origin. Sequence analysis of the candidate genes for isolated hypoparathyroidism encoding calcium-sensing receptor, parathyroid hormone, and glial cells missing homolog B did not reveal any mutations. Whole-exome sequencing identified a homozygous mutation in the autoimmune regulatory gene (AIRE), c.374A>G;p.Y85C, characteristic for Jewish Iranians with autoimmune polyendocrine syndrome type 1 (APS1), which was confirmed by the Sanger sequencing. Antibodies against the adrenal, pancreatic islet cell, ovary, thyroid, pituitary, celiac, and parietal cell were negative in both siblings, while anti-diuretic hormone antibodies were positive only in the girl. No other symptoms or signs of APS1 developed during all the years of follow-up. CONCLUSION APS1 should be part of the differential diagnosis in children presenting with isolated hypoparathyroidism or hypoparathyroidism with central diabetes insipidus (CDI). These cases show that the AIRE mutation characteristic of Iranian Jews can also be found in non-Iranian Jews.
Collapse
Affiliation(s)
- Ori Eyal
- Pediatric Endocrinology and Diabetes Unit, Dana-Dwek Children Hospital, Tel Aviv Sourasky Medical Center, 6 Weizmann St., 6423906 Tel Aviv, Israel
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Asaf Oren
- Pediatric Endocrinology and Diabetes Unit, Dana-Dwek Children Hospital, Tel Aviv Sourasky Medical Center, 6 Weizmann St., 6423906 Tel Aviv, Israel
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Harald Jüppner
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Raz Somech
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
- Cancer Research Center, Pediatric Department, Pediatric Immunology Service, Jeffery Modell Foundation (JMF) Center, Edmond and Lily Safra Children’s Hospital, Chaim Sheba Medical Center, Ramat-Gan, Israel
| | - Annamaria De Bellis
- Department of Cardiothoracic and Respiratory Sciences, Section of Endocrinology, Faculty of Medicine and Surgery, Second University of Naples, Naples, Italy
| | - Michael Mannstadt
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Auryan Szalat
- Internal Medicine Department, Endocrinology and Metabolism Service, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Margalit Bleiberg
- Clinical Immunology Laboratory, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel
| | - Yosef Weisman
- Pediatric Endocrinology and Diabetes Unit, Dana-Dwek Children Hospital, Tel Aviv Sourasky Medical Center, 6 Weizmann St., 6423906 Tel Aviv, Israel
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Naomi Weintrob
- Pediatric Endocrinology and Diabetes Unit, Dana-Dwek Children Hospital, Tel Aviv Sourasky Medical Center, 6 Weizmann St., 6423906 Tel Aviv, Israel
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| |
Collapse
|