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Friedman P, Mamonova T. The molecular sociology of NHERF1 PDZ proteins controlling renal hormone-regulated phosphate transport. Biosci Rep 2024; 44:BSR20231380. [PMID: 38465463 PMCID: PMC10987488 DOI: 10.1042/bsr20231380] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 03/07/2024] [Accepted: 03/08/2024] [Indexed: 03/12/2024] Open
Abstract
Parathyroid hormone (PTH) and fibroblast growth factor-23 (FGF23) control extracellular phosphate levels by regulating renal NPT2A-mediated phosphate transport by a process requiring the PDZ scaffold protein NHERF1. NHERF1 possesses two PDZ domains, PDZ1 and PDZ2, with identical core-binding GYGF motifs explicitly recognizing distinct binding partners that play different and specific roles in hormone-regulated phosphate transport. The interaction of PDZ1 and the carboxy-terminal PDZ-binding motif of NPT2A (C-TRL) is required for basal phosphate transport. PDZ2 is a regulatory domain that scaffolds multiple biological targets, including kinases and phosphatases involved in FGF23 and PTH signaling. FGF23 and PTH trigger disassembly of the NHERF1-NPT2A complex through reversible hormone-stimulated phosphorylation with ensuing NPT2A sequestration, down-regulation, and cessation of phosphate absorption. In the absence of NHERF1-NPT2A interaction, inhibition of FGF23 or PTH signaling results in disordered phosphate homeostasis and phosphate wasting. Additional studies are crucial to elucidate how NHERF1 spatiotemporally coordinates cellular partners to regulate extracellular phosphate levels.
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Affiliation(s)
- Peter A. Friedman
- Laboratory for G Protein-Coupled Receptor Biology, Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, U.S.A
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, U.S.A
| | - Tatyana Mamonova
- Laboratory for G Protein-Coupled Receptor Biology, Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, U.S.A
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2
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Cavalcante LBCP, Brandão CMÁ, Chiamolera MI, Biscolla RPM, Junior JVL, de Sá Tavares Russo P, Morgado JPM, de Francischi Ferrer CMA, Vieira JGH. Big data-based parathyroid hormone (PTH) values emphasize need for age correction. J Endocrinol Invest 2023; 46:2525-2533. [PMID: 37286864 PMCID: PMC10632255 DOI: 10.1007/s40618-023-02107-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Accepted: 04/30/2023] [Indexed: 06/09/2023]
Abstract
PURPOSE We aimed to study the relationship between aging and increased parathyroid hormone (PTH) values. METHODS We performed a retrospective cross-sectional study with data from patients who underwent outpatient PTH measurements performed by a second-generation electrochemiluminescence immunoassay. We included patients over 18 years of age with simultaneous PTH, calcium, and creatinine measurements and 25-OHD measured within 30 days. Patients with glomerular filtration rate < 60 mL/min/1.73 m2, altered calcemia, 25-OHD level < 20 ng/mL, PTH values > 100 pg/mL or using lithium, furosemide or antiresorptive therapy were excluded. Statistical analyses were performed using the RefineR method. RESULTS Our sample comprised 263,242 patients for the group with 25-OHD ≥ 20 ng/mL, that included 160,660 with 25-OHD ≥ 30 ng/mL. The difference in PTH values among age groups divided by decades was statistically significant (p < 0.0001), regardless of 25-OHD values, ≥ 20 or ≥ 30 ng/mL. In the group with 25-OHD ≥ 20 ng/mL and more than 60 years, the PTH values were 22.1-84.0 pg/mL, a different upper reference limit from the reference value recommended by the kit manufacturer. CONCLUSION We observed a correlation between aging and PTH increase, when measured by a second-generation immunoassay, regardless of vitamin D levels, if greater than 20 ng/mL, in normocalcemic individuals without renal dysfunction.
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Affiliation(s)
- L B C P Cavalcante
- Fleury Group, Rua Mato Grosso, 306, cj 408, Higienópolis, São Paulo, SP, 01239-040, Brazil.
| | - C M Á Brandão
- Fleury Group, Rua Mato Grosso, 306, cj 408, Higienópolis, São Paulo, SP, 01239-040, Brazil
| | - M I Chiamolera
- Fleury Group, Rua Mato Grosso, 306, cj 408, Higienópolis, São Paulo, SP, 01239-040, Brazil
| | - R P M Biscolla
- Fleury Group, Rua Mato Grosso, 306, cj 408, Higienópolis, São Paulo, SP, 01239-040, Brazil
| | - J V L Junior
- Fleury Group, Rua Mato Grosso, 306, cj 408, Higienópolis, São Paulo, SP, 01239-040, Brazil
| | - P de Sá Tavares Russo
- Fleury Group, Rua Mato Grosso, 306, cj 408, Higienópolis, São Paulo, SP, 01239-040, Brazil
| | - J P M Morgado
- Fleury Group, Rua Mato Grosso, 306, cj 408, Higienópolis, São Paulo, SP, 01239-040, Brazil
| | | | - J G H Vieira
- Fleury Group, Rua Mato Grosso, 306, cj 408, Higienópolis, São Paulo, SP, 01239-040, Brazil
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Chertok Shacham E, Maman N, Lazareva T, Masalha R, Mahagna L, Sela G, Ishay A. Normocalcemic primary hyperparathyroidism is an early stage of primary hyperparathyroidism according to fibroblast growth factor 23 level. Front Endocrinol (Lausanne) 2023; 14:1152464. [PMID: 37065752 PMCID: PMC10098304 DOI: 10.3389/fendo.2023.1152464] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Accepted: 03/13/2023] [Indexed: 04/01/2023] Open
Abstract
INTRODUCTION Normocalcemic primary hyperparathyroidism is a variant of primary hyperparathyroidism with consistently normal albumin-adjusted or free-ionized calcium levels. It may be an early stage of classic primary hyperparathyroidism or could represent primary kidney or bone disorder characterized by permanent elevation of PTH level. AIM OF THE STUDY The study aims to compare the FGF-23 levels in patients with PHPT, NPHPT, and normal calcium and PTH levels. METHODS Our study included patients who were referred to the endocrinology clinic with a presumptive diagnosis of primary hyperparathyroidism, an isolated increased level of PTH, or reduced bone densitometry. For each patient, we performed blood analysis of FGF-23, calcium, phosphate, vitamin D [25(OH)D3], estimated glomerular filtration rate (eGFR), bone turnover markers, and urine analysis for calcium/creatinine ratio. RESULTS Our study included 105 patients. Thirty patients with hypercalcemic hyperparathyroidism (HPHPT group), thirty patients with elevated PTH and normal calcium levels (NPHPT group), and 45 patients with normal calcium and PTH levels in the control group. FGF 23 level was 59.5± 23 pg/ml in the NPHPT group, 77 ± 33 pg/ml in the HPHPT group, and 49.7 ± 21.7 pg/ml in the control group (p=0.012). The phosphate level was lowest in the HPHPT group: 2.9 ± 0.6 vs 3.5 ± 0.44 in the NPHPT and 3.8 ± 0.5 in the control groups (p=0.001). No differences were found in eGFR, 25(OH)D3, C-terminal telopeptide type I collagen (CTX) and procollagen type 1 N-terminal propeptide (P1NP) levels, and bone densitometry scores between the three study groups. CONCLUSION Our findings suggest that NPHPT is an early stage of PHPT. Further studies are needed to determine the role of FGF-23 and its usefulness in NPHPT.
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Affiliation(s)
- Elena Chertok Shacham
- Endocrinology Unit, Haemek Medical Center, Afula, Israel
- *Correspondence: Elena Chertok Shacham,
| | - Nimra Maman
- Statistical Department, Haemek Medical Center, Afula, Israel
| | - Tatyana Lazareva
- Internal Medicine Department A, Haemek Medical Center, Afula, Israel
| | - Refaat Masalha
- Laboratory Medicine Department, Haemek Medical Center, Afula, Israel
| | - Lila Mahagna
- Laboratory Medicine Department, Haemek Medical Center, Afula, Israel
| | - Gala Sela
- Endocrinology Unit, Haemek Medical Center, Afula, Israel
| | - Avraham Ishay
- Endocrinology Unit, Haemek Medical Center, Afula, Israel
- Faculty of Medicine, Technion – Israel Institute of Technology, Haifa, Israel
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Pallone SG, Kunii IS, da Silva REC, Lazaretti-Castro M. Use of Teriparatide in Hyperphosphatemic Familial Tumor Calcinosis: Evaluating the Interaction Between FGF23 and PTH on the Phosphaturic Effect. Calcif Tissue Int 2022; 111:102-106. [PMID: 35338393 DOI: 10.1007/s00223-022-00969-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/05/2021] [Accepted: 03/09/2022] [Indexed: 11/02/2022]
Abstract
Hyperphosphatemic familial tumor calcinosis (HFTC) is a rare disease characterized by hyperphosphatemia and calcium and phosphorus crystal deposition. It occurs due to the loss of function of FGF23. Herein, we report a case of a 50-year-old woman diagnosed with HFTC (homozygous variant in the GALNT3 gene, c.803_804 C insertion) with a history of ectopic calcifications in the past 30 years. Laboratory tests on admission were as follows: phosphate (P) 7.1 mg/dL (Normal range (NR) 2.5-4.5 mg/dL), FGF23 c-terminal 2050 RU/mL (NR < 150 RU/mL), and intact FGF23 (iFGF23) 18.93 pg/mL (NR 12.0-69.0 pg/mL). Treatment with acetazolamide, sevelamer, and a phosphorus-restricted diet was started, but phosphatemia remained high and calcifications continued to progress. In an attempt to further decrease P, a 36-day cycle of teriparatide (TPTD) 20 mcg twice daily was added, decreasing P from 6.2 to 5.2 mg/dL and increasing the 1.25(OH)2 vitamin D by 34.2%. As urinalysis was not feasible at the end of the 36-day cycle, a second cycle was performed for another 28 days, producing a similar decrease in P (from 6.4 to 5.5 mg/mL) and an evident decrease in the rate of tubular reabsorption of P (from 97.2 to 85.3%), however, accompanied by a worrying increase in calciuria. The use of TPTD 20 mcg twice daily in a patient with genetic resistance to FGF23 (HFTC) was associated with consistent increase in phosphaturia and reduction in phosphatemia, in addition to an increase in calcitriol. The resulting hypercalciuria precludes the therapeutic use of TPTD in HFTC and suggests an important role of FGF23, not only in phosphate homeostasis but also in avoiding any excess of calcitriol.
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Affiliation(s)
- Sthefanie Giovanna Pallone
- Endocrinology Unit, Department of Medicine, Federal University of São Paulo (UNIFESP), São Paulo, SP, Brazil.
| | - Ilda Sizue Kunii
- Endocrinology Unit, Department of Medicine, Federal University of São Paulo (UNIFESP), São Paulo, SP, Brazil
| | - Renata Elen Costa da Silva
- Endocrinology Unit, Department of Medicine, Federal University of São Paulo (UNIFESP), São Paulo, SP, Brazil
| | - Marise Lazaretti-Castro
- Endocrinology Unit, Department of Medicine, Federal University of São Paulo (UNIFESP), São Paulo, SP, Brazil
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Daryadel A, Haykir B, Küng CJ, Bugarski M, Bettoni C, Schnitzbauer U, Hernando N, Hall AM, Wagner CA. Acute adaptation of renal phosphate transporters in the murine kidney to oral phosphate intake requires multiple signals. Acta Physiol (Oxf) 2022; 235:e13815. [PMID: 35334154 DOI: 10.1111/apha.13815] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Revised: 03/22/2022] [Accepted: 03/23/2022] [Indexed: 12/01/2022]
Abstract
AIMS Dietary inorganic phosphate (Pi) modulates renal Pi reabsorption by regulating the expression of the NaPi-IIa and NaPi-IIc Pi transporters. Here, we aimed to clarify the role of several Pi-regulatory mechanisms including parathyroid hormone (PTH), fibroblast growth factor 23 (FGF23) and inositol hexakisphosphate kinases (IP6-kinases) in the acute regulation of NaPi-IIa and NaPi-IIc. METHODS Wildtype (WT) and PTH-deficient mice (PTH-KO) with/without inhibition of FGF23 signalling were gavaged with Pi/saline and examined at 1, 4 and 12 h. RESULTS Pi-gavage elevated plasma Pi and decreased plasma Ca2+ in both genotypes after 1 h Within 1 h, Pi-gavage decreased NaPi-IIa abundance in WT and PTH-KO mice. NaPi-IIc was downregulated 1 h post-administration in WT and after 4 h in PTH-KO. PTH increased after 1 h in WT animals. After 4 h Pi-gavage, FGF23 increased in both genotypes being higher in the KO group. PTHrp and dopamine were not altered by Pi-gavage. Blocking FGF23 signalling blunted PTH upregulation in WT mice and reduced NaPi-IIa downregulation in PTH-KO mice 4 h after Pi-gavage. Inhibition of IP6-kinases had no effect. CONCLUSIONS (1) Acute downregulation of renal Pi transporters in response to Pi intake occurs also in the absence of PTH and FGF23 signalling, (2) when FGF23 signalling is blocked, a partial contribution of PTH is revealed, (3) IP6 kinases, intracellular Pi-sensors in yeast and bacteria, are not involved, and (4) Acute Pi does not alter PTHrp and dopamine. Thus, signals other than PTH, PTHrp, FGF23 and dopamine contribute to renal adaption.
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Affiliation(s)
- Arezoo Daryadel
- Institute of Physiology University of Zürich Zürich Switzerland
- National Center of Competence in Research Kidney.CH Zürich Switzerland
| | - Betül Haykir
- Institute of Physiology University of Zürich Zürich Switzerland
| | | | - Milica Bugarski
- National Center of Competence in Research Kidney.CH Zürich Switzerland
- Institute of Anatomy University of Zürich Zürich Switzerland
| | - Carla Bettoni
- Institute of Physiology University of Zürich Zürich Switzerland
| | | | - Nati Hernando
- Institute of Physiology University of Zürich Zürich Switzerland
| | - Andrew M. Hall
- National Center of Competence in Research Kidney.CH Zürich Switzerland
- Institute of Anatomy University of Zürich Zürich Switzerland
| | - Carsten A. Wagner
- Institute of Physiology University of Zürich Zürich Switzerland
- National Center of Competence in Research Kidney.CH Zürich Switzerland
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Shum W, Zhang BL, Cao AS, Zhou X, Shi SM, Zhang ZY, Gu LY, Shi S. Calcium Homeostasis in the Epididymal Microenvironment: Is Extracellular Calcium a Cofactor for Matrix Gla Protein-Dependent Scavenging Regulated by Vitamins. Front Cell Dev Biol 2022; 10:827940. [PMID: 35252193 PMCID: PMC8893953 DOI: 10.3389/fcell.2022.827940] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Accepted: 01/19/2022] [Indexed: 12/23/2022] Open
Abstract
In the male reproductive tract, the epididymis is an essential organ for sperm maturation, in which sperm cells acquire mobility and the ability to fertilize oocytes while being stored in a protective microenvironment. Epididymal function involves a specialized luminal microenvironment established by the epithelial cells of epididymal mucosa. Low-calcium concentration is a unique feature of this epididymal luminal microenvironment, its relevance and regulation are, however, incompletely understood. In the rat epididymis, the vitamin D-related calcium-dependent TRPV6-TMEM16A channel-coupler has been shown to be involved in fluid transport, and, in a spatially complementary manner, vitamin K2-related γ-glutamyl carboxylase (GGCX)-dependent carboxylation of matrix Gla protein (MGP) plays an essential role in promoting calcium-dependent protein aggregation. An SNP in the human GGCX gene has been associated with asthenozoospermia. In addition, bioinformatic analysis also suggests the involvement of a vitamin B6-axis in calcium-dependent MGP-mediated protein aggregation. These findings suggest that vitamins interact with calcium homeostasis in the epididymis to ensure proper sperm maturation and male fertility. This review article discusses the regulation mechanisms of calcium homeostasis in the epididymis, and the potential role of vitamin interactions on epididymal calcium homeostasis, especially the role of matrix calcium in the epididymal lumen as a cofactor for the carboxylated MGP-mediated scavenging function.
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Affiliation(s)
- Winnie Shum
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
- Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Shanghai, China
- *Correspondence: Winnie Shum,
| | - Bao Li Zhang
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
- Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Shanghai, China
- NHC Key Lab of Reproduction Regulation, Shanghai Institute for Biomedical and Pharmaceutical Technologies, Reproduction and Development Institution, Fudan University, Shanghai, China
| | - Albert Shang Cao
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Xin Zhou
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Su Meng Shi
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Ze Yang Zhang
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Lou Yi Gu
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Shuo Shi
- Shanghai Institute for Advanced Immunochemical Studies, ShanghaiTech University, Shanghai, China
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7
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Yang M, Luo S, Yang J, Chen W, He L, Liu D, Zhao L, Wang X. Bone-kidney axis: A potential therapeutic target for diabetic nephropathy. Front Endocrinol (Lausanne) 2022; 13:996776. [PMID: 36353239 PMCID: PMC9637707 DOI: 10.3389/fendo.2022.996776] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Accepted: 09/26/2022] [Indexed: 11/13/2022] Open
Abstract
Diabetic nephropathy (DN) is the leading cause of end-stage renal disease (ESRD). However, its pathogenesis remains unclear, and effective prevention and treatment strategies are lacking. Recently, organ-to-organ communication has become a new focus of studies on pathogenesis. Various organs or tissues (the liver, muscle and adipose tissue) secrete a series of proteins or peptides to regulate the homeostasis of distal organs in an endocrine manner. Bone, an important part of the body, can also secrete bone-derived proteins or peptides that act on distal organs. As an organ with high metabolism, the kidney is responsible for signal and material exchange with other organs at any time through circulation. In this review, we briefly discussed bone composition and changes in bone structure and function in DN and summarized the current status of bone-derived proteins and their role in the progression of DN. We speculated that the "bone-kidney axis" is a potential target for early diagnosis and treatment of DN.
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Affiliation(s)
- Ming Yang
- Department of Nutrition, Xiangya Hospital, Central South University, Changsha, China
- Department of Nephrology, The Second Xiangya Hospital of Central South University, Changsha, China
| | - Shilu Luo
- Department of Nephrology, The Second Xiangya Hospital of Central South University, Changsha, China
| | - Jinfei Yang
- Department of Nephrology, The Second Xiangya Hospital of Central South University, Changsha, China
| | - Wei Chen
- Department of Nephrology, The Second Xiangya Hospital of Central South University, Changsha, China
| | - Liyu He
- Department of Nephrology, The Second Xiangya Hospital of Central South University, Changsha, China
| | - Di Liu
- Department of Nephrology, The Second Xiangya Hospital of Central South University, Changsha, China
| | - Li Zhao
- Department of Reproduction and Genetics, The First Affiliated Hospital of Kunming Medical University, Kunming, China
| | - Xi Wang
- Department of Nutrition, Xiangya Hospital, Central South University, Changsha, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
- *Correspondence: Xi Wang,
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8
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Abstract
Apart from its phosphaturic action, the bone-derived hormone fibroblast growth factor-23 (FGF23) is also an essential regulator of vitamin D metabolism. The main target organ of FGF23 is the kidney, where FGF23 suppresses transcription of the key enzyme in vitamin D hormone (1,25(OH)2D) activation, 1α-hydroxylase, and activates transcription of the key enzyme responsible for vitamin D degradation, 24-hydroxylase, in proximal renal tubules. The circulating concentration of 1,25(OH)2D is a positive regulator of FGF23 secretion in bone, forming a feedback loop between kidney and bone. The importance of FGF23 as regulator of vitamin D metabolism is underscored by the fact that in the absence of FGF23 signaling, the tight control of renal 1α-hydroxylase fails, resulting in overproduction of 1,25(OH)2D in mice and men. During recent years, big strides have been made toward a more complete understanding of the mechanisms underlying the FGF23-mediated regulation of vitamin D metabolism, especially at the genomic level. However, there are still major gaps in our knowledge that need to be filled by future research. Importantly, the intracellular signaling cascades downstream of FGF receptors regulating transcription of 1α-hydroxylase and 24-hydroxylase in proximal renal tubules still remain unresolved. The purpose of this review is to highlight our current understanding of the molecular mechanisms underlying the regulation of vitamin D metabolism by FGF23, and to discuss the role of these mechanisms in physiology and pathophysiology. © 2021 The Authors. JBMR Plus published by Wiley Periodicals LLC. on behalf of American Society for Bone and Mineral Research.
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Affiliation(s)
- Nejla Latic
- Department of Biomedical Sciences University of Veterinary Medicine Vienna Austria
| | - Reinhold G Erben
- Department of Biomedical Sciences University of Veterinary Medicine Vienna Austria
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9
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Endocrine role of bone in the regulation of energy metabolism. Bone Res 2021; 9:25. [PMID: 34016950 PMCID: PMC8137703 DOI: 10.1038/s41413-021-00142-4] [Citation(s) in RCA: 52] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Revised: 12/20/2020] [Accepted: 01/12/2021] [Indexed: 02/06/2023] Open
Abstract
Bone mainly functions as a supportive framework for the whole body and is the major regulator of calcium homeostasis and hematopoietic function. Recently, an increasing number of studies have characterized the significance of bone as an endocrine organ, suggesting that bone-derived factors regulate local bone metabolism and metabolic functions. In addition, these factors can regulate global energy homeostasis by altering insulin sensitivity, feeding behavior, and adipocyte commitment. These findings may provide a new pathological mechanism for related metabolic diseases or be used in the diagnosis, treatment, and prevention of metabolic diseases such as osteoporosis, obesity, and diabetes mellitus. In this review, we summarize the regulatory effect of bone and bone-derived factors on energy metabolism and discuss directions for future research.
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10
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Bird RP, Eskin NAM. The emerging role of phosphorus in human health. ADVANCES IN FOOD AND NUTRITION RESEARCH 2021; 96:27-88. [PMID: 34112356 DOI: 10.1016/bs.afnr.2021.02.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Phosphorus, an essential nutrient, performs vital functions in skeletal and non-skeletal tissues and is pivotal for energy production. The last two decades of research on the physiological importance of phosphorus have provided several novel insights about its dynamic nature as a nutrient performing functions as a phosphate ion. Phosphorous also acts as a signaling molecule and induces complex physiological responses. It is recognized that phosphorus homeostasis is critical for health. The intake of phosphorus by the general population world-wide is almost double the amount required to maintain health. This increase is attributed to the incorporation of phosphate containing food additives in processed foods purchased by consumers. Research findings assessed the impact of excessive phosphorus intake on cells' and organs' responses, and highlighted the potential pathogenic consequences. Research also identified a new class of bioactive phosphates composed of polymers of phosphate molecules varying in chain length. These polymers are involved in metabolic responses including hemostasis, brain and bone health, via complex mechanism(s) with positive or negative health effects, depending on their chain length. It is amazing, that phosphorus, a simple element, is capable of exerting multiple and powerful effects. The role of phosphorus and its polymers in the renal and cardiovascular system as well as on brain health appear to be important and promising future research directions.
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Affiliation(s)
- Ranjana P Bird
- School of Health Sciences, University of Northern British Columbia, Prince George, BC, Canada.
| | - N A Michael Eskin
- Department of Food and Human Nutritional Sciences, Faculty of Agricultural and Food Sciences, University of Manitoba, Winnipeg, MB, Canada
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11
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Qamar H, Perumal N, Papp E, Gernand AD, Al Mahmud A, Roth DE. Higher maternal parathyroid hormone concentration at delivery is not associated with smaller newborn size. Endocr Connect 2021; 10:345-357. [PMID: 33640873 PMCID: PMC8052570 DOI: 10.1530/ec-21-0056] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Accepted: 02/23/2021] [Indexed: 11/08/2022]
Abstract
Intrauterine growth restriction (IUGR) reflects inadequate growth in-utero and is prevalent in low resource settings. This study aimed to assess the association of maternal delivery parathyroid hormone (PTH) - a regulator of bone turnover and calcium homeostasis - with newborn anthropometry, to identify regulators of PTH, and to delineate pathways by which maternal PTH regulates birth size using path analysis. This was a cross-sectional analysis of data from participants (n = 537) enrolled in the Maternal Vitamin D for Infant Growth trial in Dhaka, Bangladesh. Primary exposures were maternal delivery intact PTH (iPTH) or whole PTH (wPTH) and outcomes were gestational age- and sex-standardized z-scores for birth length (LAZ), weight (WAZ), and head circumference (HCAZ). Hypothesized regulators of PTH included calcium and protein intake, vitamin D, magnesium, fibroblast-like growth factor-23 (FGF23), and C-reactive protein. Maternal iPTH was not associated with birth size in linear regression analyses; however, in path analysis models, every SD increase in log(iPTH) was associated with 0.08SD (95% CI: 0.002, 0.162) higher LAZ. In linear regression and path analysis models, wPTH was positively associated with WAZ. Vitamin D suppressed PTH, while FGF23 was positively associated with PTH. In path analysis models, higher magnesium was negatively associated with LAZ; FGF23 was positively associated and protein intake was negatively associated with LAZ, WAZ, and HCAZ. Higher maternal PTH in late pregnancy is unlikely to contribute to IUGR. Future studies should investigate maternal FGF23, magnesium and protein intake as regulators of fetal growth, particularly in settings where food insecurity and IUGR are public health problems.
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Affiliation(s)
- Huma Qamar
- Centre for Global Child Health, Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Nutritional Sciences, University of Toronto, Toronto, Ontario, Canada
| | - Nandita Perumal
- Centre for Global Child Health, Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Epidemiology, Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada
| | - Eszter Papp
- Centre for Global Child Health, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Alison D Gernand
- Department of Nutritional Sciences, Pennsylvania State University, University Park, Pennsylvania, USA
| | - Abdullah Al Mahmud
- Nutrition and Clinical Services Division, International Centre for Diarrhoeal Disease Research (icddr,b), Dhaka, Bangladesh
| | - Daniel E Roth
- Centre for Global Child Health, Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Nutritional Sciences, University of Toronto, Toronto, Ontario, Canada
- Department of Paediatrics, Hospital for Sick Children and University of Toronto, Toronto, Ontario, Canada
- Correspondence should be addressed to D E Roth:
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12
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Agoro R, Ni P, Noonan ML, White KE. Osteocytic FGF23 and Its Kidney Function. Front Endocrinol (Lausanne) 2020; 11:592. [PMID: 32982979 PMCID: PMC7485387 DOI: 10.3389/fendo.2020.00592] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Accepted: 07/20/2020] [Indexed: 12/16/2022] Open
Abstract
Osteocytes, which represent up to 95% of adult skeletal cells, are deeply embedded in bone. These cells exhibit important interactive abilities with other bone cells such as osteoblasts and osteoclasts to control skeletal formation and resorption. Beyond this local role, osteocytes can also influence the function of distant organs due to the presence of their sophisticated lacunocanalicular system, which connects osteocyte dendrites directly to the vasculature. Through these networks, osteocytes sense changes in circulating metabolites and respond by producing endocrine factors to control homeostasis. One critical function of osteocytes is to respond to increased blood phosphate and 1,25(OH)2 vitamin D (1,25D) by producing fibroblast growth factor-23 (FGF23). FGF23 acts on the kidneys through partner fibroblast growth factor receptors (FGFRs) and the co-receptor Klotho to promote phosphaturia via a downregulation of phosphate transporters, as well as the control of vitamin D metabolizing enzymes to reduce blood 1,25D. In the first part of this review, we will explore the signals involved in the positive and negative regulation of FGF23 in osteocytes. In the second portion, we will bridge bone responses with the review of current knowledge on FGF23 endocrine functions in the kidneys.
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Affiliation(s)
- Rafiou Agoro
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN, United States
| | - Pu Ni
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN, United States
| | - Megan L. Noonan
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN, United States
| | - Kenneth E. White
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN, United States
- Medicine/Division of Nephrology, Indiana University School of Medicine, Indianapolis, IN, United States
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13
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Saki F, Kassaee SR, Salehifar A, Omrani GHR. Interaction between serum FGF-23 and PTH in renal phosphate excretion, a case-control study in hypoparathyroid patients. BMC Nephrol 2020; 21:176. [PMID: 32398014 PMCID: PMC7218502 DOI: 10.1186/s12882-020-01826-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2019] [Accepted: 04/22/2020] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND phosphate homeostasis is mediated through complex counter regulatory feed-back balance between parathyroid hormone, FGF-23 and 1,25(OH)2D. Both parathyroid hormone and FGF-23 regulate proximal tubular phosphate excretion through signaling on sodium- phosphate cotransporters IIa and IIc. However, the interaction between these hormones on phosphate excretion is not clearly understood. We performed the present study to evaluate whether the existence of sufficient parathyroid hormone is necessary for full phosphaturic function of FGF-23 or not. METHODS In this case-control study, 19 patients with hypoparathyroidism and their age- and gender-matched normal population were enrolled. Serum calcium, phosphate, alkaline phosphatase,parathyroid hormone, FGF-23, 25(OH)D, 1,25(OH)2D and Fractional excretion of phosphorous were assessed and compared between the two groups, using SPSS software. RESULTS The mean serum calcium and parathyroid hormone level was significantly lower in hypoparathyroid patients in comparison with the control group (P < 0.001 and P < 0.001, respectively). We found high serum level of phosphate and FGF-23 in hypoparathyroid patients compared to the control group (P < 0.001 and P < 0.001, respectively). However, there was no significant difference in Fractional excretion of phosphorous or 1,25OH2D level between the two groups. There was a positive correlation between serum FGF-23 and Fractional excretion of phosphorous just in the normal individuals (P < 0.001, r = 0.79). CONCLUSIONS Although the FGF-23 is a main regulator of urinary phosphate excretion but the existence of sufficient parathyroid hormone is necessary for the full phosphaturic effect of FGF-23.
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Affiliation(s)
- Forough Saki
- Shiraz Endocrinology and Metabolism Research Center, Shiraz University of Medical Sciences, P.O. Box: 71345-1744, Shiraz, Iran
| | - Seyed Reza Kassaee
- Shiraz Endocrinology and Metabolism Research Center, Shiraz University of Medical Sciences, P.O. Box: 71345-1744, Shiraz, Iran
| | - Azita Salehifar
- Shiraz Endocrinology and Metabolism Research Center, Shiraz University of Medical Sciences, P.O. Box: 71345-1744, Shiraz, Iran
| | - Gholam Hossein Ranjbar Omrani
- Shiraz Endocrinology and Metabolism Research Center, Shiraz University of Medical Sciences, P.O. Box: 71345-1744, Shiraz, Iran.
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14
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Luo Y, Ye S, Li X, Lu W. Emerging Structure-Function Paradigm of Endocrine FGFs in Metabolic Diseases. Trends Pharmacol Sci 2019; 40:142-153. [PMID: 30616873 DOI: 10.1016/j.tips.2018.12.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Revised: 11/08/2018] [Accepted: 12/04/2018] [Indexed: 12/12/2022]
Abstract
Endocrine fibroblast growth factors (eFGFs) control pathways that are crucial for maintaining metabolic homeostasis of lipids, glucose, energy, bile acids, and minerals. Unlike the heparin-binding paracrine FGFs, eFGFs require a unique Klotho family protein to form a productive triad complex, but the structural and mechanistical details of this complex have remained obscure since the beginning of the eFGF field. However, recent breakthroughs in resolving the 3D structures of eFGF signaling complexes have now unveiled the atomic details of multivalent interactions among eFGF, FGFR, and Klotho. We provide here a timely review on the architecture and the structure-function relationships of these complexes, and highlight how the structural knowledge opens a new door to structure-based drug design against a repertoire of eFGF-associated metabolic diseases.
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Affiliation(s)
- Yongde Luo
- School of Pharmaceutical Science, Wenzhou Medical University, Center for Cancer and Metabolism Research, Institute for Life Science, Wenzhou University, Wenzhou, Zhejiang 325000, China; Proteomics and Nanotechnology Laboratory, Center for Cancer and Stem Cell Biology, Institute of Biosciences and Technology, Texas A&M University Health Science Center, Houston, TX 77030, USA; Current address: Centeer BioTherapeutics Ltd Co., Houston, TX 77021, USA.
| | - Sheng Ye
- School of Life Science, Tianjin University, Tianjin 300072, China; Life Sciences Institute and Innovation Center for Cell Signaling Network, Zhejiang University, Huangzhou, Zhejiang 310058, China.
| | - Xiaokun Li
- School of Pharmaceutical Science, Wenzhou Medical University, Center for Cancer and Metabolism Research, Institute for Life Science, Wenzhou University, Wenzhou, Zhejiang 325000, China.
| | - Weiqin Lu
- Division of Gastroenterology and Hepatology, Department of Medicine, Stony Brook University School of Medicine, 101 Nicolls Road, Stony Brook, NY 11794, USA.
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15
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Veyrat M, Fessi H, Haymann JP, Ronco P, Lacau St Guily J, Périé S. Conservative three-quarter versus subtotal seven-eighths parathyroidectomy in secondary hyperparathyroidism. Eur Ann Otorhinolaryngol Head Neck Dis 2018; 136:63-68. [PMID: 30327179 DOI: 10.1016/j.anorl.2018.09.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
OBJECTIVE There is at present no consensus concerning surgical techniques for secondary hyperparathyroidism (SHPT) in end-stage renal disease (ESRD). Although both subtotal and total parathyroidectomy provide low rates of recurrence, they may induce hypoparathyroidism, damaging the bone and cardiovascular systems. The aim of our study was to compare 3/4 and 7/8 parathyroidectomy in this population and to discuss the potential benefit of more conservative treatment. STUDY DESIGN Prospective observational study in a university teaching hospital between 2010 and 2014. METHODS The study included 34 consecutive ESRD patients with SHPT: 19 underwent 3/4 parathyroidectomy (group A*3/4) and 15 underwent 7/8 parathyroidectomy (group B*7/8). Serum intact 1-84 PTH levels (before and 6 months after surgery) and hospital stay were compared between the two groups. RESULTS Before surgery, PTH levels were similar between the two groups. At month 6 following surgery, median PTH levels were significantly higher in group A*3/4 than in group B*7/8 (109 versus 24pg/mL, respectively; P<0.0006). Hospital stay was shorter in group A*3/4 (4.79 versus 6.80 days, respectively; P=0.008). Postoperative hypoparathyroidism requiring long-term calcium and 1alpha(OH) D3 treatment was reported in 5% of patients in group A*3/4 and 26% of patients in group B*7/8 (P=0.04). CONCLUSIONS In this preliminary study, 3/4 conservative parathyroidectomy seemed effective and safe, with less reported morbidity than 7/8 parathyroidectomy, as assessed by lower rates of irreversible hypoparathyroidism and shorter hospital stay. LEVEL OF EVIDENCE 3b, individual case-control study.
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Affiliation(s)
- M Veyrat
- Department of Otolaryngology Head and Neck Surgery, Tenon Hospital, Faculty of Medicine Sorbonne University, Assistance publique-Hôpitaux de Paris, AP-HP, 4, Rue de la Chine, 75020 Paris, France
| | - H Fessi
- Department of Nephrology-Dialysis, Tenon Hospital, Faculty of Medicine Sorbonne University, Assistance publique-Hôpitaux de Paris, AP-HP, 4, Rue de la Chine, 75020 Paris, France
| | - J-P Haymann
- Department of Functional Renal Explorations, Tenon Hospital, Faculty of Medicine Sorbonne University, Assistance publique-Hôpitaux de Paris, AP-HP, 4, Rue de la Chine, 75020 Paris, France
| | - P Ronco
- Department of Nephrology-Dialysis, Tenon Hospital, Faculty of Medicine Sorbonne University, Assistance publique-Hôpitaux de Paris, AP-HP, 4, Rue de la Chine, 75020 Paris, France
| | - J Lacau St Guily
- Department of Otolaryngology Head and Neck Surgery, Tenon Hospital, Faculty of Medicine Sorbonne University, Assistance publique-Hôpitaux de Paris, AP-HP, 4, Rue de la Chine, 75020 Paris, France
| | - S Périé
- Department of Otolaryngology Head and Neck Surgery, Tenon Hospital, Faculty of Medicine Sorbonne University, Assistance publique-Hôpitaux de Paris, AP-HP, 4, Rue de la Chine, 75020 Paris, France.
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16
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Minamizaki T, Konishi Y, Sakurai K, Yoshioka H, Aubin JE, Kozai K, Yoshiko Y. Soluble Klotho causes hypomineralization in Klotho-deficient mice. J Endocrinol 2018; 237:285-300. [PMID: 29632215 DOI: 10.1530/joe-17-0683] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Accepted: 04/09/2018] [Indexed: 12/12/2022]
Abstract
The type I transmembrane protein αKlotho (Klotho) serves as a coreceptor for the phosphaturic hormone fibroblast growth factor 23 (FGF23) in kidney, while a truncated form of Klotho (soluble Klotho, sKL) is thought to exhibit multiple activities, including acting as a hormone, but whose mode(s) of action in different organ systems remains to be fully elucidated. FGF23 is expressed primarily in osteoblasts/osteocytes and aberrantly high levels in the circulation acting via signaling through an FGF receptor (FGFR)-Klotho coreceptor complex cause renal phosphate wasting and osteomalacia. We assessed the effects of exogenously added sKL on osteoblasts and bone using Klotho-deficient (kl/kl) mice and cell and organ cultures. sKL induced FGF23 signaling in bone and exacerbated the hypomineralization without exacerbating the hyperphosphatemia, hypercalcemia and hypervitaminosis D in kl/kl mice. The same effects were seen in rodent bone models in vitro, in which we also detected formation of a sKL complex with FGF23-FGFR and decreased Phex (gene responsible for X-linked hypophosphatemic rickets (XLH)/osteomalacia) expression. Further, sKL-FGF23-dependent hypomineralization in vitro was rescued by soluble PHEX. These data suggest that exogenously added sKL directly participates in FGF23 signaling in bone and that PHEX is a downstream effector of the sKL-FGF23-FGFR axis in bone.
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Affiliation(s)
- Tomoko Minamizaki
- Department of Calcified Tissue Biology, School of Dentistry, Hiroshima University Graduate School of Biomedical & Health Sciences, Hiroshima, Japan
| | - Yukiko Konishi
- Department of Calcified Tissue Biology, School of Dentistry, Hiroshima University Graduate School of Biomedical & Health Sciences, Hiroshima, Japan
- Department of Pediatric Dentistry, School of Dentistry, Hiroshima University Graduate School of Biomedical & Health Sciences, Hiroshima, Japan
| | - Kaoru Sakurai
- Department of Calcified Tissue Biology, School of Dentistry, Hiroshima University Graduate School of Biomedical & Health Sciences, Hiroshima, Japan
- Department of Pediatric Dentistry, School of Dentistry, Hiroshima University Graduate School of Biomedical & Health Sciences, Hiroshima, Japan
| | - Hirotaka Yoshioka
- Department of Calcified Tissue Biology, School of Dentistry, Hiroshima University Graduate School of Biomedical & Health Sciences, Hiroshima, Japan
| | - Jane E Aubin
- Department of Molecular Genetics, University of Toronto, 1 King's College Circle, Toronto, Canada
| | - Katsuyuki Kozai
- Department of Pediatric Dentistry, School of Dentistry, Hiroshima University Graduate School of Biomedical & Health Sciences, Hiroshima, Japan
| | - Yuji Yoshiko
- Department of Calcified Tissue Biology, School of Dentistry, Hiroshima University Graduate School of Biomedical & Health Sciences, Hiroshima, Japan
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17
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Glosse P, Feger M, Mutig K, Chen H, Hirche F, Hasan AA, Gaballa MMS, Hocher B, Lang F, Föller M. AMP-activated kinase is a regulator of fibroblast growth factor 23 production. Kidney Int 2018; 94:491-501. [PMID: 29861059 DOI: 10.1016/j.kint.2018.03.006] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Revised: 03/01/2018] [Accepted: 03/08/2018] [Indexed: 12/20/2022]
Abstract
Fibroblast growth factor 23 (FGF23) is a proteohormone regulating renal phosphate transport and vitamin D metabolism as well as inducing left heart hypertrophy. FGF23-deficient mice suffer from severe tissue calcification, accelerated aging and a myriad of aging-associated diseases. Bone cells produce FGF23 upon store-operated calcium ion entry (SOCE) through the calcium selective ion channel Orai1. AMP-activated kinase (AMPK) is a powerful energy sensor helping cells survive states of energy deficiency, and AMPK down-regulates Orai1. Here we investigated the role of AMPK in FGF23 production. Fgf23 gene transcription was analyzed by qRT-PCR and SOCE by fluorescence optics in UMR106 osteoblast-like cells while the serum FGF23 concentration and phosphate metabolism were assessed in AMPKα1-knockout and wild-type mice. The AMPK activator, 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR) down-regulated, whereas the AMPK inhibitor, dorsomorphin dihydrochloride (compound C) and AMPK gene silencing induced Fgf23 transcription. AICAR decreased membrane abundance of Orai1 and SOCE. SOCE inhibitors lowered Fgf23 gene expression induced by AMPK inhibition. AMPKα1-knockout mice had a higher serum FGF23 concentration compared to wild-type mice. Thus, AMPK participates in the regulation of FGF23 production in vitro and in vivo. The inhibitory effect of AMPK on FGF23 production is at least in part mediated by Orai1-involving SOCE.
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Affiliation(s)
- Philipp Glosse
- Department of Agricultural and Nutritional Sciences, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany
| | - Martina Feger
- Department of Agricultural and Nutritional Sciences, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany
| | - Kerim Mutig
- Department of Anatomy, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Hong Chen
- Department of Physiology I, Eberhard-Karls University of Tübingen, Tübingen, Germany
| | - Frank Hirche
- Department of Agricultural and Nutritional Sciences, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany
| | | | | | - Berthold Hocher
- Department of Nutritional Sciences, University of Potsdam, Potsdam, Germany
| | - Florian Lang
- Department of Physiology I, Eberhard-Karls University of Tübingen, Tübingen, Germany
| | - Michael Föller
- Department of Agricultural and Nutritional Sciences, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany.
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18
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Abstract
Fibroblast growth factor-23 (FGF23) is a bone-derived hormone suppressing phosphate reabsorption and vitamin D hormone synthesis in the kidney. At physiological concentrations of the hormone, the endocrine actions of FGF23 in the kidney are αKlotho-dependent, because high-affinity binding of FGF23 to FGF receptors requires the presence of the co-receptor αKlotho on target cells. It is well established that excessive concentrations of intact FGF23 in the blood lead to phosphate wasting in patients with normal kidney function. Based on the importance of diseases associated with gain of FGF23 function such as phosphate-wasting diseases and chronic kidney disease, a large body of literature has focused on the pathophysiological consequences of FGF23 excess. Less emphasis has been put on the role of FGF23 in normal physiology. Nevertheless, during recent years, lessons we have learned from loss-of-function models have shown that besides the paramount physiological roles of FGF23 in the control of 1α-hydroxylase expression and of apical membrane expression of sodium-phosphate co-transporters in proximal renal tubules, FGF23 also is an important stimulator of calcium and sodium reabsorption in distal renal tubules. In addition, there is an emerging role of FGF23 as an auto-/paracrine regulator of alkaline phosphatase expression and mineralization in bone. In contrast to the renal actions of FGF23, the FGF23-mediated suppression of alkaline phosphatase in bone is αKlotho-independent. Moreover, FGF23 may be a physiological suppressor of differentiation of hematopoietic stem cells into the erythroid lineage in the bone microenvironment. At present, there is little evidence for a physiological role of FGF23 in organs other than kidney and bone. The purpose of this mini-review is to highlight the current knowledge about the complex physiological functions of FGF23.
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19
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Yang H, Ahn C, Shin EK, Lee JS, An BS, Jeung EB. NCKX3 was compensated by calcium transporting genes and bone resorption in a NCKX3 KO mouse model. Mol Cell Endocrinol 2017; 454:93-102. [PMID: 28602864 DOI: 10.1016/j.mce.2017.06.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Revised: 05/18/2017] [Accepted: 06/06/2017] [Indexed: 01/10/2023]
Abstract
Gene knockout is the most powerful tool for determination of gene function or permanent modification of the phenotypic characteristics of an animal. Existing methods for gene disruption are limited by their efficiency, time required for completion and potential for confounding off-target effects. In this study, a rapid single-step approach to knockout of a targeted gene in mice using zinc-finger nucleases (ZFNs) was demonstrated for generation of mutant (knockout; KO) alleles. Specifically, ZFNs to target the sodium/calcium/potassium exchanger3 (NCKX3) gene in C57bl/6j were designed using the concept of this approach. NCKX3 KO mice were generated and the phenotypic characterization and molecular regulation of active calcium transporting genes was assessed when mice were fed different calcium diets during growth. General phenotypes such as body weight and plasma ion level showed no distinct abnormalities. Thus, the potassium/sodium/calcium exchanger of NCKX3 KO mice proceeded normally in this study. As a result, the compensatory molecular regulation of this mechanism was elucidated. Renal TRPV5 mRNA of NCKX3 KO mice increased in both male and female mice. Expression of TRPV6 mRNA was only down-regulated in the duodenum of male KO mice. Renal- and duodenal expression of PTHR and VDR were not changed; however, GR mRNA expression was increased in the kidney of NCKX3 KO mice. Depletion of the NCKX3 gene in a KO mouse model showed loss of bone mineral contents and increased plasma parathyroid hormone, suggesting that NCKX3 may play a role in regulating calcium homeostasis.
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Affiliation(s)
- Hyun Yang
- Laboratory of Veterinary Biochemistry and Molecular Biology, Veterinary Medical Center and College of Veterinary Medicine, Chungbuk National University, Cheongju, Chungbuk 28644, Republic of Korea; Korean Medicine Convergence Research Division, Korea Institute of Oriental Medicine, Daejeon 34054, Republic of Korea
| | - Changhwan Ahn
- Laboratory of Veterinary Biochemistry and Molecular Biology, Veterinary Medical Center and College of Veterinary Medicine, Chungbuk National University, Cheongju, Chungbuk 28644, Republic of Korea
| | - Eun-Kyeong Shin
- Laboratory of Veterinary Biochemistry and Molecular Biology, Veterinary Medical Center and College of Veterinary Medicine, Chungbuk National University, Cheongju, Chungbuk 28644, Republic of Korea
| | - Ji-Sun Lee
- Laboratory of Veterinary Biochemistry and Molecular Biology, Veterinary Medical Center and College of Veterinary Medicine, Chungbuk National University, Cheongju, Chungbuk 28644, Republic of Korea
| | - Beum-Soo An
- Department of Biomaterials Science, College of National Resources & Life Science, Pusan National University, Miryang, Gyeongsangnam-do 627-706, Republic of Korea
| | - Eui-Bae Jeung
- Laboratory of Veterinary Biochemistry and Molecular Biology, Veterinary Medical Center and College of Veterinary Medicine, Chungbuk National University, Cheongju, Chungbuk 28644, Republic of Korea.
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20
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Lee JJ, Plain A, Beggs MR, Dimke H, Alexander RT. Effects of phospho- and calciotropic hormones on electrolyte transport in the proximal tubule. F1000Res 2017; 6:1797. [PMID: 29043081 PMCID: PMC5627579 DOI: 10.12688/f1000research.12097.1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 10/04/2017] [Indexed: 12/17/2022] Open
Abstract
Calcium and phosphate are critical for a myriad of physiological and cellular processes within the organism. Consequently, plasma levels of calcium and phosphate are tightly regulated. This occurs through the combined effects of the phospho- and calciotropic hormones, parathyroid hormone (PTH), active vitamin D
3, and fibroblast growth factor 23 (FGF23). The organs central to this are the kidneys, intestine, and bone. In the kidney, the proximal tubule reabsorbs the majority of filtered calcium and phosphate, which amounts to more than 60% and 90%, respectively. The basic molecular mechanisms responsible for phosphate reclamation are well described, and emerging work is delineating the molecular identity of the paracellular shunt wherein calcium permeates the proximal tubular epithelium. Significant experimental work has delineated the molecular effects of PTH and FGF23 on these processes as well as their regulation of active vitamin D
3 synthesis in this nephron segment. The integrative effects of both phospho- and calciotropic hormones on proximal tubular solute transport and subsequently whole body calcium-phosphate balance thus have been further complicated. Here, we first review the molecular mechanisms of calcium and phosphate reabsorption from the proximal tubule and how they are influenced by the phospho- and calciotropic hormones acting on this segment and then consider the implications on both renal calcium and phosphate handling as well as whole body mineral balance.
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Affiliation(s)
- Justin J Lee
- Department of Physiology, University of Alberta, Edmonton, Canada.,The Women and Children's Health Research Institute, Edmonton, Canada
| | - Allein Plain
- Department of Physiology, University of Alberta, Edmonton, Canada.,The Women and Children's Health Research Institute, Edmonton, Canada
| | - Megan R Beggs
- Department of Physiology, University of Alberta, Edmonton, Canada.,The Women and Children's Health Research Institute, Edmonton, Canada
| | - Henrik Dimke
- Department of Cardiovascular and Renal Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark
| | - R Todd Alexander
- Department of Physiology, University of Alberta, Edmonton, Canada.,The Women and Children's Health Research Institute, Edmonton, Canada.,Department of Pediatrics, Edmonton Clinic Health Academy, University of Alberta, Edmonton, Canada
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21
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Andrukhova O, Bayer J, Schüler C, Zeitz U, Murali SK, Ada S, Alvarez-Pez JM, Smorodchenko A, Erben RG. Klotho Lacks an FGF23-Independent Role in Mineral Homeostasis. J Bone Miner Res 2017; 32:2049-2061. [PMID: 28600880 DOI: 10.1002/jbmr.3195] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Revised: 05/30/2017] [Accepted: 06/09/2017] [Indexed: 12/30/2022]
Abstract
Fibroblast growth factor-23 (FGF23) is a bone-derived hormone regulating vitamin D hormone production and renal handling of minerals by signaling through an FGF receptor/αKlotho (Klotho) receptor complex. Whether Klotho has FGF23-independent effects on mineral homeostasis is a controversial issue. Here, we aimed to shed more light on this controversy by comparing male and female triple knockout mice with simultaneous deficiency in Fgf23 and Klotho and a nonfunctioning vitamin D receptor (VDR) (Fgf23/Klotho/VDR) with double (Fgf23/VDR, Klotho/VDR, and Fgf23/Klotho) and single Fgf23, Klotho, and VDR mutants. As expected, 4-week-old Fgf23, Klotho, and Fgf23/Klotho knockout mice were hypercalcemic and hyperphosphatemic, whereas VDR, Fgf23/VDR, and Klotho/VDR mice on rescue diet were normocalcemic and normophosphatemic. Serum levels of calcium, phosphate, and sodium did not differ between 4-week-old triple Fgf23/Klotho/VDR and double Fgf23/VDR or Klotho/VDR knockout mice. Notably, 3-month-old Fgf23/Klotho/VDR triple knockout mice were indistinguishable from double Fgf23/VDR and Klotho/VDR compound mutants in terms of serum calcium, serum phosphate, serum sodium, and serum PTH, as well as urinary calcium and sodium excretion. Protein expression analysis revealed increased membrane abundance of sodium-phosphate co-transporter 2a (NaPi-2a), and decreased expression of sodium-chloride co-transporter (NCC) and transient receptor potential cation channel subfamily V member 5 (TRPV5) in Fgf23/Klotho/VDR, Fgf23/VDR, and Klotho/VDR mice, relative to wild-type and VDR mice, but no differences between triple and double knockouts. Further, ex vivo treatment of live kidney slices isolated from wild-type and Klotho/VDR mice with soluble Klotho did not induce changes in intracellular phosphate, calcium or sodium accumulation assessed by two-photon microscopy. In conclusion, our data suggest that the main physiological function of Klotho for mineral homeostasis in vivo is its role as co-receptor mediating Fgf23 action. © 2017 American Society for Bone and Mineral Research.
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Affiliation(s)
- Olena Andrukhova
- Department of Biomedical Sciences, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Jessica Bayer
- Department of Biomedical Sciences, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Christiane Schüler
- Department of Biomedical Sciences, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Ute Zeitz
- Department of Biomedical Sciences, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Sathish K Murali
- Department of Biomedical Sciences, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Sibel Ada
- Department of Biomedical Sciences, University of Veterinary Medicine Vienna, Vienna, Austria
| | | | - Alina Smorodchenko
- Institute for Vegetative Anatomy, Charité University of Berlin, Berlin, Germany
| | - Reinhold G Erben
- Department of Biomedical Sciences, University of Veterinary Medicine Vienna, Vienna, Austria
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22
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Parathyroid hormone and the regulation of renal tubular calcium transport. Curr Opin Nephrol Hypertens 2017; 26:405-410. [DOI: 10.1097/mnh.0000000000000347] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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23
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Alimohammadi N, Javadian P, Malekpour A, Tahmasebian S. Association of serum fibroblast growth factor 23 with calcium metabolism in patients with end-stage renal disease undergoing hemodialysis. J Nephropathol 2017. [DOI: 10.15171/jnp.2017.57] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
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24
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Erben RG, Andrukhova O. FGF23-Klotho signaling axis in the kidney. Bone 2017; 100:62-68. [PMID: 27622885 DOI: 10.1016/j.bone.2016.09.010] [Citation(s) in RCA: 103] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/05/2016] [Revised: 09/08/2016] [Accepted: 09/09/2016] [Indexed: 01/04/2023]
Abstract
Fibroblast growth factor-23 (FGF23) is a bone-derived hormone protecting against the potentially deleterious effects of hyperphosphatemia by suppression of phosphate reabsorption and of active vitamin D hormone synthesis in the kidney. The kidney is one of the main target organs of FGF23 signaling. The purpose of this review is to highlight the recent advances in the area of FGF23-Klotho signaling in the kidney. During recent years, it has become clear that FGF23 acts independently on proximal and distal tubular epithelium. In proximal renal tubules, FGF23 suppresses phosphate reabsorption by a Klotho dependent activation of extracellular signal-regulated kinase-1/2 (ERK1/2) and of serum/glucocorticoid-regulated kinase-1 (SGK1), leading to phosphorylation of the scaffolding protein Na+/H+ exchange regulatory cofactor (NHERF)-1 and subsequent internalization and degradation of sodium-phosphate cotransporters. In distal renal tubules, FGF23 augments calcium and sodium reabsorption by increasing the apical membrane expression of the epithelial calcium channel TRPV5 and of the sodium-chloride cotransporter NCC through a Klotho dependent activation of with-no-lysine kinase-4 (WNK4). In proximal and distal renal tubules, FGF receptor-1 is probably the dominant FGF receptor mediating the effects of FGF23 by forming a complex with membrane-bound Klotho in the basolateral membrane. The newly described sodium- and calcium-conserving functions of FGF23 may have major implications for the pathophysiology of diseases characterized by chronically increased circulating FGF23 concentrations such as chronic kidney disease.
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Park YE, Musson DS, Naot D, Cornish J. Cell–cell communication in bone development and whole-body homeostasis and pharmacological avenues for bone disorders. Curr Opin Pharmacol 2017; 34:21-35. [DOI: 10.1016/j.coph.2017.04.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Revised: 03/07/2017] [Accepted: 04/06/2017] [Indexed: 12/11/2022]
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Phelps KR. Tradeoff-in-the-Nephron: A Theory to Explain the Primacy of Phosphate in the Pathogenesis of Secondary Hyperparathyroidism. Nutrients 2017; 9:E427. [PMID: 28445401 PMCID: PMC5452157 DOI: 10.3390/nu9050427] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Revised: 04/10/2017] [Accepted: 04/17/2017] [Indexed: 02/06/2023] Open
Abstract
Chronic kidney disease (CKD) causes secondary hyperparathyroidism (SHPT). The cardinal features of SHPT are persistence of normocalcemia as CKD progresses and dependence of the parathyroid hormone concentration ([PTH]) on phosphate influx (IP). The tradeoff-in-the-nephron hypothesis integrates these features. It states that as the glomerular filtration rate (GFR) falls, the phosphate concentration ([P]CDN) rises in the cortical distal nephron, the calcium concentration ([Ca]CDN) in that segment falls, and [PTH] rises to maintain normal calcium reabsorption per volume of filtrate (TRCa/GFR). In a clinical study, we set GFR equal to creatinine clearance (Ccr) and IP equal to the urinary excretion rate of phosphorus (EP). We employed EP/Ccr as a surrogate for [P]CDN. We showed that TRCa/Ccr was high in patients with primary hyperparathyroidism (PHPT) and normal in those with SHPT despite comparably increased [PTH] in each group. In subjects with SHPT, we examined regressions of [PTH] on EP/Ccr before and after treatment with sevelamer carbonate or a placebo. All regressions were significant, and ∆[PTH] correlated with ∆EP/Ccr in each treatment cohort. We concluded that [P]CDN determines [PTH] in CKD. This inference explains the cardinal features of SHPT, much of the evidence on which other pathogenic theories are based, and many ancillary observations.
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Affiliation(s)
- Kenneth R Phelps
- Research Service, Stratton Veterans' Affairs Medical Center, Albany, NY 12208, USA.
- Department of Medicine, Division of Nephrology, Albany Medical College, Albany, NY 12208, USA.
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Mitchell DM, Jüppner H, Burnett-Bowie SAM. FGF23 Is Not Associated With Age-Related Changes in Phosphate, but Enhances Renal Calcium Reabsorption in Girls. J Clin Endocrinol Metab 2017; 102:1151-1160. [PMID: 28323960 PMCID: PMC5460726 DOI: 10.1210/jc.2016-4038] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/27/2016] [Accepted: 01/25/2017] [Indexed: 02/06/2023]
Abstract
CONTEXT Fibroblast growth factor (FGF)23 is a critical determinant of phosphate homeostasis. The role of FGF23, however, in regulating physiologic changes in serum phosphate and renal phosphate handling across childhood is not well described. In addition, animal models have suggested a role for FGF23 in regulating renal calcium excretion. OBJECTIVE To assess changes in FGF23 concentrations across childhood in relation to changes in mineral ions and hormones of mineral ion homeostasis. DESIGN This was a cross-sectional study. SETTING The study was conducted at a Clinical Research Center at a tertiary care hospital. PATIENTS OR OTHER PARTICIPANTS Ninety healthy girls ages 9 to 18 years were recruited from the surrounding community. MAIN OUTCOME MEASURES The associations of intact and C-terminal FGF23 concentrations with measures of mineral ion homeostasis were determined by univariable and multivariable linear regression. RESULTS Serum phosphate and renal phosphate excretion varied with age, as expected (R = -0.49, P < 0.001 and R = -0.48, P < 0.001, respectively). Neither intact nor C-terminal FGF23 varied with age, and FGF23 was not correlated with serum or urinary phosphate. Intact FGF23 was positively correlated with serum calcium (R = 0.39, P < 0.001) and negatively correlated with urinary calcium/creatinine ratio (R = -0.27, P = 0.011). CONCLUSIONS The changes in serum and urinary phosphate handling across childhood do not appear to be determined by alterations in FGF23 concentrations. These data may point to a role for FGF23 in calcium regulation in human physiology.
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Affiliation(s)
| | - Harald Jüppner
- Endocrine Unit,
- Pediatric Nephrology Unit, Massachusetts General Hospital, Boston, Massachusetts 02114
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Kaneko I, Tatsumi S, Segawa H, Miyamoto KI. Control of phosphate balance by the kidney and intestine. Clin Exp Nephrol 2016; 21:21-26. [PMID: 27900568 DOI: 10.1007/s10157-016-1359-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2016] [Accepted: 11/07/2016] [Indexed: 01/06/2023]
Abstract
The prevention and correction of hyperphosphatemia are major goals of the treatment of chronic kidney disease (CKD)-bone mineral disorders, and thus, Pi balance requires special attention. Pi balance is maintained by intestinal absorption, renal excretion, and bone accretion. The kidney is mainly responsible for the plasma Pi concentration. In CKD, reduced glomerular filtration rate leads to various Pi metabolism abnormalities, and Pi absorption in the small intestine also has an important role in Pi metabolism. Disturbances in Pi metabolism are mediated by a series of complex changes in regulatory hormones originating from the skeleton, intestine, parathyroid gland, and kidney. In this review, we describe the regulation of type II sodium-dependent Pi co-transporters by the kidney and intestine, including the regulation of Pi transport, circadian rhythm, and the vicious circle between salivary Pi secretion and intestinal Pi absorption in animals with and without CKD.
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Affiliation(s)
- Ichiro Kaneko
- Department of Molecular Nutrition, Institute of Biomedical Sciences, Tokushima University Graduate School, 3-18-15 Kuramoto-Cho, Tokushima, 770-8503, Japan
| | - Sawako Tatsumi
- Department of Molecular Nutrition, Institute of Biomedical Sciences, Tokushima University Graduate School, 3-18-15 Kuramoto-Cho, Tokushima, 770-8503, Japan
| | - Hiroko Segawa
- Department of Molecular Nutrition, Institute of Biomedical Sciences, Tokushima University Graduate School, 3-18-15 Kuramoto-Cho, Tokushima, 770-8503, Japan
| | - Ken-Ichi Miyamoto
- Department of Molecular Nutrition, Institute of Biomedical Sciences, Tokushima University Graduate School, 3-18-15 Kuramoto-Cho, Tokushima, 770-8503, Japan.
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