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Florance JA, Schollum JBW, Pomeranc A, Endre ZH, Walker RJ. Autosomal dominant hypercalciuric hypocalcaemia: the calcium-sensing receptor in renal calcium homeostasis and the impact of renal transplantation. Intern Med J 2024; 54:852-860. [PMID: 38665051 DOI: 10.1111/imj.16403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2024] [Accepted: 03/28/2024] [Indexed: 06/18/2024]
Abstract
Calcium-sensing receptors (CaSRs) are G protein-coupled receptors that help maintain Ca2+ concentrations, modulating calciotropic hormone release (parathyroid hormone (PTH), calcitonin and 1,25-dihydroxyvitamin D) by direct actions in the kidneys, gastrointestinal tract and bone. Variability in population calcium levels has been attributed to single nucleotide polymorphisms in CaSR genes, and several conditions affecting calcium and phosphate homeostasis have been attributed to gain- or loss-of-function mutations. An example is autosomal dominant hypercalciuric hypocalcaemia, because of a missense mutation at codon 128 of chromosome 3, as reported in our specific case and her family. As a consequence of treating symptomatic hypocalcaemia as a child, this female subject slowly developed progressive end-stage kidney failure because of nephrocalcinosis and nephrolithiasis. After kidney transplantation, she remains asymptomatic, with decreased vitamin D and elemental calcium requirements, stable fluid and electrolyte homeostasis during intercurrent illnesses and has normalised urinary calcium and phosphate excretion, reducing the likelihood of hypercalciuria-induced graft impairment. We review the actions of the CaSR, its role in regulating renal Ca2+ homeostasis along with the impact of a proven gain-of-function mutation in the CaSR gene resulting in autosomal dominant hypercalciuric hypocalcaemia before and after kidney transplantation.
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Affiliation(s)
- James A Florance
- Department of Nephrology, Dunedin Hospital, Dunedin, Otago, New Zealand
| | - John B W Schollum
- Department of Nephrology, Dunedin Hospital, Dunedin, Otago, New Zealand
| | - Abigail Pomeranc
- Department of Nephrology, Dunedin Hospital, Dunedin, Otago, New Zealand
| | - Zoltan H Endre
- Department of Nephrology, Prince of Wales Clinical School, UNSW Medicine, Sydney, New South Wales, Australia
| | - Robert J Walker
- Department of Nephrology, Dunedin Hospital, Dunedin, Otago, New Zealand
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Walker V. The Intricacies of Renal Phosphate Reabsorption-An Overview. Int J Mol Sci 2024; 25:4684. [PMID: 38731904 PMCID: PMC11083860 DOI: 10.3390/ijms25094684] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2024] [Revised: 04/17/2024] [Accepted: 04/19/2024] [Indexed: 05/13/2024] Open
Abstract
To maintain an optimal body content of phosphorus throughout postnatal life, variable phosphate absorption from food must be finely matched with urinary excretion. This amazing feat is accomplished through synchronised phosphate transport by myriads of ciliated cells lining the renal proximal tubules. These respond in real time to changes in phosphate and composition of the renal filtrate and to hormonal instructions. How they do this has stimulated decades of research. New analytical techniques, coupled with incredible advances in computer technology, have opened new avenues for investigation at a sub-cellular level. There has been a surge of research into different aspects of the process. These have verified long-held beliefs and are also dramatically extending our vision of the intense, integrated, intracellular activity which mediates phosphate absorption. Already, some have indicated new approaches for pharmacological intervention to regulate phosphate in common conditions, including chronic renal failure and osteoporosis, as well as rare inherited biochemical disorders. It is a rapidly evolving field. The aim here is to provide an overview of our current knowledge, to show where it is leading, and where there are uncertainties. Hopefully, this will raise questions and stimulate new ideas for further research.
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Affiliation(s)
- Valerie Walker
- Department of Clinical Biochemistry, University Hospital Southampton NHS Foundation Trust, Southampton General Hospital, Southampton S016 6YD, UK
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3
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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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Perwad F, Akwo EA, Vartanian N, Suva LJ, Friedman PA, Robinson-Cohen C. Multi-trait Analysis of GWAS for circulating FGF23 Identifies Novel Network Interactions Between HRG-HMGB1 and Cardiac Disease in CKD. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2024:2024.03.04.24303051. [PMID: 38496593 PMCID: PMC10942519 DOI: 10.1101/2024.03.04.24303051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/19/2024]
Abstract
Background Genome-wide association studies (GWAS) have identified numerous genetic loci associated with mineral metabolism (MM) markers but have exclusively focused on single-trait analysis. In this study, we performed a multi-trait analysis of GWAS (MTAG) of MM, exploring overlapping genetic architecture between traits, to identify novel genetic associations for fibroblast growth factor 23 (FGF23). Methods We applied MTAG to genetic variants common to GWAS of 5 genetically correlated MM markers (calcium, phosphorus, FGF23, 25-hydroxyvitamin D (25(OH)D) and parathyroid hormone (PTH)) in European-ancestry subjects. We integrated information from UKBioBank GWAS for blood levels for phosphate, 25(OH)D and calcium (n=366,484), and CHARGE GWAS for PTH (n=29,155) and FGF23 (n=16,624). We then used functional genomics to model interactive and dynamic networks to identify novel associations between genetic traits and circulating FGF23. Results MTAG increased the effective sample size for all MM markers to n=50,325 for FGF23. After clumping, MTAG identified independent genome-wide significant SNPs for all traits, including 62 loci for FGF23. Many of these loci have not been previously reported in single-trait analyses. Through functional genomics we identified Histidine-rich glycoprotein (HRG) and high mobility group box 1(HMGB1) genes as master regulators of downstream canonical pathways associated with FGF23. HRG-HMGB1 network interactions were also highly enriched in left ventricular heart tissue of a cohort of deceased hemodialysis patients. Conclusion Our findings highlight the importance of MTAG analysis of MM markers to boost the number of genome-wide significant loci for FGF23 to identify novel genetic traits. Functional genomics revealed novel networks that inform unique cellular functions and identified HRG-HMGB1 as key master regulators of FGF23 and cardiovascular disease in CKD. Future studies will provide a deeper understanding of genetic signatures associated with FGF23 and its role in health and disease.
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Affiliation(s)
- Farzana Perwad
- University of California San Francisco, San Francisco, CA
| | - Elvis A Akwo
- Vanderbilt University Medical Center, Nashville, TN
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Staubitz JI, Musholt TJ. [Current indications and operative strategy for renal hyperparathyroidism]. CHIRURGIE (HEIDELBERG, GERMANY) 2023:10.1007/s00104-023-01878-x. [PMID: 37140660 DOI: 10.1007/s00104-023-01878-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 04/05/2023] [Indexed: 05/05/2023]
Abstract
BACKGROUND Renal hyperparathyroidism results from pathophysiologic changes induced and maintained by terminal renal failure. Surgical treatment is possible using various resection strategies. AIM OF THE WORK (RESEARCH QUESTION) The aim of this work is to illustrate the indications, techniques and resection strategies for surgical treatment of renal hyperparathyroidism. MATERIAL AND METHODS National and international guidelines regarding the surgical treatment of renal hyperparathyroidism were analyzed. Furthermore, our own practical experience was integrated into the article. RESULTS While the indications for surgery according to the Surgical Working Group Endocrinology (CAEK) guidelines are given in cases of clinical impairment and renal hyperparathyroidism that cannot be controlled by medication, international guidelines additionally refer to the absolute parathyroid hormone level for deciding for surgery. DISCUSSION Individual patient consultation is necessary in the case of renal hyperparathyroidism in order to determine the right time for surgical treatment as well as the most suitable surgical technique, taking into account the individual risk profile and other therapeutic perspectives, including renal transplantation.
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Affiliation(s)
- Julia I Staubitz
- Sektion Endokrine Chirurgie, Klinik für Allgemein‑, Viszeral- und Transplantationschirurgie, Universitätsmedizin Mainz, Johannes-Gutenberg-Universität Mainz, Langenbeckstr. 1, 55131, Mainz, Deutschland
| | - Thomas J Musholt
- Sektion Endokrine Chirurgie, Klinik für Allgemein‑, Viszeral- und Transplantationschirurgie, Universitätsmedizin Mainz, Johannes-Gutenberg-Universität Mainz, Langenbeckstr. 1, 55131, Mainz, Deutschland.
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Laster ML, Rowan B, Chen HC, Schwantes-An TH, Sheng X, Friedman PA, Ikizler TA, Sinshiemer JS, Ix JH, Susztak K, de Boer IH, Kestenbaum B, Hung A, Moe SM, Perwad F, Robinson-Cohen C. Genetic Variants Associated With Mineral Metabolism Traits in Chronic Kidney Disease. J Clin Endocrinol Metab 2022; 107:e3866-e3876. [PMID: 35587600 PMCID: PMC9387704 DOI: 10.1210/clinem/dgac318] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Indexed: 02/01/2023]
Abstract
CONTEXT Chronic kidney disease (CKD) causes multiple interrelated disturbances in mineral metabolism. Genetic studies in the general population have identified common genetic variants associated with circulating phosphate, calcium, parathyroid hormone (PTH), and fibroblast growth factor 23 (FGF23). OBJECTIVE In this study we aimed to discover genetic variants associated with circulating mineral markers in CKD. METHODS We conducted candidate single-nucleotide variation (SNV) analysis in 3027 participants in the multiethnic Chronic Renal Insufficiency Cohort (CRIC) to determine the associations between SNVs and circulating levels of mineral markers. RESULTS SNVs adjacent to or within genes encoding the regulator of G protein-coupled signaling 14 (RGS14) and the calcium-sensing receptor (CASR) were associated with levels of mineral metabolites. The strongest associations (P < .001) were at rs4074995 (RGS14) for phosphate (0.09 mg/dL lower per minor allele) and FGF23 (8.6% lower), and at rs1801725 (CASR) for calcium (0.12 mg/dL higher). In addition, the prevalence of hyperparathyroidism differed by rs4074995 (RGS14) genotype (chi-square P < .0001). Differential inheritance by race was noted for the minor allele of RGS14. Expression quantitative loci (eQTL) analysis showed that rs4074995 was associated with lower RGS14 gene expression in glomeruli (P = 1.03 × 10-11) and tubules (P = 4.0 × 10-4). CONCLUSION We evaluated genetic variants associated with mineral metabolism markers in a CKD population. Participants with CKD and the minor allele of rs4074995 (RGS14) had lower phosphorus, lower plasma FGF23, and lower prevalence of hyperparathyroidism. The minor allele of RGS14 was also associated with lower gene expression in the kidney. Further studies are needed to elucidate the effect of rs4074995 on the pathogenesis of disordered mineral metabolism in CKD.
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Affiliation(s)
- Marciana L Laster
- Correspondence: Marciana L. Laster, MD, UCLA Department of Pediatrics, Division of Pediatric Nephrology, 10833 Le Conte Ave, MDCC A2-383, Los Angeles, CA 90095-1752, USA.
| | - Bryce Rowan
- Department of Biostatistics, Vanderbilt University Medical Center, Nashville, Tennessee 37232, USA
| | - Hua-Chang Chen
- Department of Biostatistics, Vanderbilt University Medical Center, Nashville, Tennessee 37232, USA
| | - Tae-Hwi Schwantes-An
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, Indiana 46202, USA
| | - Xin Sheng
- Department of Medicine and Genetics, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Peter A Friedman
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213, USA
| | - T Alp Ikizler
- Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Vanderbilt O’Brien Center for Kidney Disease, Vanderbilt University Medical Center, Nashville, Tennessee 37232, USA
| | - Janet S Sinshiemer
- Department of Human Genetics and Computational Medicine, David Geffen School of Medicine at UCLA, Los Angeles, California 90095-1752, USA
- Department of Biostatistics, UCLA Fielding School of Public Health, Los Angeles, California 90095-1752, USA
| | - Joachim H Ix
- Department of Medicine, University of California, San Diego, San Diego, California 92161, USA
| | - Katalin Susztak
- Department of Medicine and Genetics, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Ian H de Boer
- Department of Medicine, University of Washington, Seattle, Washington 98195-6420, USA
| | - Bryan Kestenbaum
- Kidney Research Institute, University of Washington, Seattle, Washington 98195-6420, USA
| | - Adriana Hung
- Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Sharon M Moe
- Clinical Translational Sciences Institute, Indiana University School of Medicine, Indianapolis, Indiana 46202, USA
- Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana 46202, USA
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Yoon SH, Tang CC, Wein MN. Salt inducible kinases and PTH1R action. VITAMINS AND HORMONES 2022; 120:23-45. [PMID: 35953111 DOI: 10.1016/bs.vh.2022.04.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Parathyroid hormone is a central regulator of calcium homeostasis. PTH protects the organism from hypocalcemia through its actions in bone and kidney. Recent physiologic studies have revealed key target genes for PTH receptor (PTH1R) signaling in these target organs. However, the complete signal transduction cascade used by PTH1R to accomplish these physiologic actions has remained poorly defined. Here we will review recent studies that have defined an important role for salt inducible kinases downstream of PTH1R in bone, cartilage, and kidney. PTH1R signaling inhibits the activity of salt inducible kinases. Therefore, direct SIK inhibitors represent a promising novel strategy to mimic PTH actions using small molecules. Moreover, a detailed understanding of the molecular circuitry used by PTH1R to exert its biologic effects will afford powerful new models to better understand the diverse actions of this important G protein coupled receptor in health and disease.
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Affiliation(s)
- Sung-Hee Yoon
- Endocrine Unit, Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States
| | - Cheng-Chia Tang
- Endocrine Unit, Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States
| | - Marc N Wein
- Endocrine Unit, Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States.
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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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Friedman PA, Sneddon WB, Mamonova T, Montanez-Miranda C, Ramineni S, Harbin NH, Squires KE, Gefter JV, Magyar CE, Emlet DR, Hepler JR. RGS14 regulates PTH- and FGF23-sensitive NPT2A-mediated renal phosphate uptake via binding to the NHERF1 scaffolding protein. J Biol Chem 2022; 298:101836. [PMID: 35307350 PMCID: PMC9035407 DOI: 10.1016/j.jbc.2022.101836] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 03/04/2022] [Accepted: 03/06/2022] [Indexed: 02/06/2023] Open
Abstract
Phosphate homeostasis, mediated by dietary intake, renal absorption, and bone deposition, is incompletely understood because of the uncharacterized roles of numerous implicated protein factors. Here, we identified a novel role for one such element, regulator of G protein signaling 14 (RGS14), suggested by genome-wide association studies to associate with dysregulated Pi levels. We show that human RGS14 possesses a carboxy-terminal PDZ ligand required for sodium phosphate cotransporter 2a (NPT2A) and sodium hydrogen exchanger regulatory factor-1 (NHERF1)-mediated renal Pi transport. In addition, we found using isotope uptake measurements combined with bioluminescence resonance energy transfer assays, siRNA knockdown, pull-down and overlay assays, and molecular modeling that secreted proteins parathyroid hormone (PTH) and fibroblast growth factor 23 inhibited Pi uptake by inducing dissociation of the NPT2A-NHERF1 complex. PTH failed to affect Pi transport in cells expressing RGS14, suggesting that it suppresses hormone-sensitive but not basal Pi uptake. Interestingly, RGS14 did not affect PTH-directed G protein activation or cAMP formation, implying a postreceptor site of action. Further pull-down experiments and direct binding assays indicated that NPT2A and RGS14 bind distinct PDZ domains on NHERF1. We showed that RGS14 expression in human renal proximal tubule epithelial cells blocked the effects of PTH and fibroblast growth factor 23 and stabilized the NPT2A-NHERF1 complex. In contrast, RGS14 genetic variants bearing mutations in the PDZ ligand disrupted RGS14 binding to NHERF1 and subsequent PTH-sensitive Pi transport. In conclusion, these findings identify RGS14 as a novel regulator of hormone-sensitive Pi transport. The results suggest that changes in RGS14 function or abundance may contribute to the hormone resistance and hyperphosphatemia observed in kidney diseases.
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Affiliation(s)
- Peter A Friedman
- Laboratory for GPCR Biology, Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA; Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA.
| | - W Bruce Sneddon
- Laboratory for GPCR Biology, Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Tatyana Mamonova
- Laboratory for GPCR Biology, Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Carolina Montanez-Miranda
- Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Suneela Ramineni
- Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Nicholas H Harbin
- Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Katherine E Squires
- Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Julia V Gefter
- Laboratory for GPCR Biology, Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Clara E Magyar
- Department of Pathology and Laboratory Medicine, The David Geffen School of Medicine at UCLA, Los Angeles, California, USA
| | - David R Emlet
- Center for Critical Care Nephrology, Department of Critical Care Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - John R Hepler
- Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, Georgia, USA.
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Figueres L, Beck-Cormier S, Beck L, Marks J. The Complexities of Organ Crosstalk in Phosphate Homeostasis: Time to Put Phosphate Sensing Back in the Limelight. Int J Mol Sci 2021; 22:5701. [PMID: 34071837 PMCID: PMC8199323 DOI: 10.3390/ijms22115701] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2021] [Revised: 05/13/2021] [Accepted: 05/21/2021] [Indexed: 12/16/2022] Open
Abstract
Phosphate homeostasis is essential for health and is achieved via interaction between the bone, kidney, small intestine, and parathyroid glands and via intricate processes involving phosphate transporters, phosphate sensors, and circulating hormones. Numerous genetic and acquired disorders are associated with disruption in these processes and can lead to significant morbidity and mortality. The role of the kidney in phosphate homeostasis is well known, although it is recognized that the cellular mechanisms in murine models and humans are different. Intestinal phosphate transport also appears to differ in humans and rodents, with recent studies demonstrating a dominant role for the paracellular pathway. The existence of phosphate sensing has been acknowledged for decades; however, the underlying molecular mechanisms are poorly understood. At least three phosphate sensors have emerged. PiT2 and FGFR1c both act as phosphate sensors controlling Fibroblast Growth Factor 23 secretion in bone, whereas the calcium-sensing receptor controls parathyroid hormone secretion in response to extracellular phosphate. All three of the proposed sensors are expressed in the kidney and intestine but their exact function in these organs is unknown. Understanding organ interactions and the mechanisms involved in phosphate sensing requires significant research to develop novel approaches for the treatment of phosphate homeostasis disorders.
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Affiliation(s)
- Lucile Figueres
- Department of Neuroscience, Physiology and Pharmacology, Royal Free Campus, University College London, London NW3 2PF, UK;
- CHU de Nantes, Université de Nantes, F-44042 Nantes, France
| | - Sarah Beck-Cormier
- Inserm, UMR 1229, RMeS Regenerative Medicine and Skeleton, Université de Nantes, ONIRIS, F-44042 Nantes, France; (S.B.-C.); (L.B.)
| | - Laurent Beck
- Inserm, UMR 1229, RMeS Regenerative Medicine and Skeleton, Université de Nantes, ONIRIS, F-44042 Nantes, France; (S.B.-C.); (L.B.)
| | - Joanne Marks
- Department of Neuroscience, Physiology and Pharmacology, Royal Free Campus, University College London, London NW3 2PF, UK;
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Saki F, Salehifar A, Kassaee SR, Omrani GR. Association of vitamin D and FGF23 with serum ferritin in hypoparathyroid thalassemia: a case control study. BMC Nephrol 2020; 21:482. [PMID: 33198660 PMCID: PMC7667728 DOI: 10.1186/s12882-020-02101-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Accepted: 10/14/2020] [Indexed: 12/20/2022] Open
Abstract
Background FGF23 controls serum l,25(OH)2D3 levels and phosphate homeostasis. This study evaluates the effects of ferritin on intact PTH, FGF23, and l,25(OH)2D3 in patients with major thalassemia. It also evaluates FGF23 changes in patients with hypoparathyroidism to clarify the interaction between FGF23 and PTH in the absence of proper PTH functioning in human. Methods In this case-control study, 25 major-beta thalassemia patients with hypoparathyroidism were age- and gender-matched with major-beta thalassemia patients having normal parathyroid function. Biochemical studies assessed the serum calcium, albumin, phosphorus, alkaline phosphatase, PTH, FGF23, 25(OH) D, 1,25(OH)2D3, ferritin, and the fractional excretion of phosphorous. Results FGF23 was higher in the patients with hypoparathyroidism than the controls (P = 0.002). The fractional excretion of phosphorous was lower in patients with hypoparathyroidism, despite the high level of FGF23 (P = 0.001). There was a correlation between serum 1,25(OH)2D3 and FGF23 with ferritin in the controls (P = < 0.001and P = < 0.001, respectively). Conclusions The present study showed a strong positive correlation between serum ferritin and levels of FGF23 and 1,25(OH)2D3. We hypothesized that ferritin could have a stimulatory effect on the production of 1,25(OH)2D3. Moreover, a rise in FGF23 in patients with thalassemia, might be either associated with the stimulating effect of PTH and 1,25(OH)2D3, or directly related to the stimulating effect of ferritin.
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Affiliation(s)
- Forough Saki
- Shiraz Endocrinology and Metabolism Research Cente, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Azita Salehifar
- Shiraz Endocrinology and Metabolism Research Cente, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Seyed Reza Kassaee
- Shiraz Endocrinology and Metabolism Research Cente, Shiraz University of Medical Sciences, Shiraz, Iran
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12
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Bushau-Sprinkle AM, Lederer ED. New roles of the Na +/H + exchange regulatory factor 1 scaffolding protein: a review. Am J Physiol Renal Physiol 2020; 318:F804-F808. [PMID: 31984791 DOI: 10.1152/ajprenal.00467.2019] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Na+/H+ exchange regulatory factor 1 (NHERF1), a member of a PDZ scaffolding protein family, was first identified as an organizer of membrane-bound protein complexes composed of hormone receptors, signal transduction pathways, and electrolyte and mineral transporters and channels. NHERF1 is involved in the regulation of Na+/H+ exchanger 3, Na+-dependent phosphate transporter 2a, and Na+-K+-ATPase through its ability to scaffold these transporters to the plasma membrane, allowing regulation of these protein complexes with their associated hormone receptors. Recently, NHERF1 has received increased interest in its involvement in a variety of functions, including cell structure and trafficking, tumorigenesis and tumor behavior, inflammatory responses, and tissue injury. In this review, we highlight the evidence for the expansive role of NHERF1 in cell biology and speculate on the implications for renal physiology and pathophysiology.
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Affiliation(s)
- Adrienne M Bushau-Sprinkle
- Department of Pharmacology and Toxicology, University of Louisville, Louisville, Kentucky.,Robley Rex Veterans Affairs Medical Center, Louisville, Kentucky
| | - Eleanor D Lederer
- Division of Nephrology, Department of Medicine, University of Louisville, Louisville, Kentucky.,Robley Rex Veterans Affairs Medical Center, Louisville, Kentucky
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13
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Martins JS, Liu ES, Sneddon WB, Friedman PA, Demay MB. 1,25-Dihydroxyvitamin D Maintains Brush Border Membrane NaPi2a and Attenuates Phosphaturia in Hyp Mice. Endocrinology 2019; 160:2204-2214. [PMID: 31237611 PMCID: PMC6735734 DOI: 10.1210/en.2019-00186] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Accepted: 06/19/2019] [Indexed: 12/21/2022]
Abstract
Phosphate homeostasis is critical for many cellular processes and is tightly regulated. The sodium-dependent phosphate cotransporter, NaPi2a, is the major regulator of urinary phosphate reabsorption in the renal proximal tubule. Its activity is dependent upon its brush border localization that is regulated by fibroblast growth factor 23 (FGF23) and PTH. High levels of FGF23, as are seen in the Hyp mouse model of human X-linked hypophosphatemia, lead to renal phosphate wasting. Long-term treatment of Hyp mice with 1,25-dihydroxyvitamin D (1,25D) or 1,25D analogues has been shown to improve renal phosphate wasting in the setting of increased FGF23 mRNA expression. Studies were undertaken to define the cellular and molecular basis for this apparent FGF23 resistance. 1,25D increased FGF23 protein levels in the cortical bone and circulation of Hyp mice but did not impair FGF23 cleavage. 1,25D attenuated urinary phosphate wasting as early as one hour postadministration, without suppressing FGF23 receptor/coreceptor expression. Although 1,25D treatment induced expression of early growth response 1, an early FGF23 responsive gene required for its phosphaturic effects, it paradoxically enhanced renal phosphate reabsorption and NaPi2a protein expression in renal brush border membranes (BBMs) within one hour. The Na-H+ exchange regulatory factor 1 (NHERF1) is a scaffolding protein thought to anchor NaPi2a to the BBM. Although 1,25D did not alter NHERF1 protein levels acutely, it enhanced NHERF1-NaPi2a interactions in Hyp mice. 1,25D also prevented the decrease in NHERF1/NaPi2a interactions in PTH-treated wild-type mice. Thus, these investigations identify a novel role for 1,25D in the hormonal regulation of renal phosphate handling.
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Affiliation(s)
- Janaina S Martins
- Endocrine Unit, Massachusetts General Hospital, Boston, Massachusetts
- Harvard Medical School, Boston, Massachusetts
| | - Eva S Liu
- Endocrine Unit, Massachusetts General Hospital, Boston, Massachusetts
- Harvard Medical School, Boston, Massachusetts
- Division of Endocrinology Diabetes and Hypertension, Brigham and Women’s Hospital, Boston, Massachusetts
| | - W Bruce Sneddon
- Laboratory for GPCR Biology, Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Peter A Friedman
- Laboratory for GPCR Biology, Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Marie B Demay
- Endocrine Unit, Massachusetts General Hospital, Boston, Massachusetts
- Harvard Medical School, Boston, Massachusetts
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14
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15
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Czaya B, Faul C. The Role of Fibroblast Growth Factor 23 in Inflammation and Anemia. Int J Mol Sci 2019; 20:E4195. [PMID: 31461904 PMCID: PMC6747522 DOI: 10.3390/ijms20174195] [Citation(s) in RCA: 57] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Revised: 08/22/2019] [Accepted: 08/23/2019] [Indexed: 02/07/2023] Open
Abstract
In patients with chronic kidney disease (CKD), adverse outcomes such as systemic inflammation and anemia are contributing pathologies which increase the risks for cardiovascular mortality. Amongst these complications, abnormalities in mineral metabolism and the metabolic milieu are associated with chronic inflammation and iron dysregulation, and fibroblast growth factor 23 (FGF23) is a risk factor in this context. FGF23 is a bone-derived hormone that is essential for regulating vitamin D and phosphate homeostasis. In the early stages of CKD, serum FGF23 levels rise 1000-fold above normal values in an attempt to maintain normal phosphate levels. Despite this compensatory action, clinical CKD studies have demonstrated powerful and dose-dependent associations between FGF23 levels and higher risks for mortality. A prospective pathomechanism coupling elevated serum FGF23 levels with CKD-associated anemia and cardiovascular injury is its strong association with chronic inflammation. In this review, we will examine the current experimental and clinical evidence regarding the role of FGF23 in renal physiology as well as in the pathophysiology of CKD with an emphasis on chronic inflammation and anemia.
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Affiliation(s)
- Brian Czaya
- Division of Nephrology, Department of Medicine, The University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Christian Faul
- Division of Nephrology, Department of Medicine, The University of Alabama at Birmingham, Birmingham, AL 35294, USA.
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16
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Abstract
Hypophosphatemic rickets, mostly of the X-linked dominant form caused by pathogenic variants of the PHEX gene, poses therapeutic challenges with consequences for growth and bone development and portends a high risk of fractions and poor bone healing, dental problems and nephrolithiasis/nephrocalcinosis. Conventional treatment consists of PO4 supplements and calcitriol requiring monitoring for treatment-emergent adverse effects. FGF23 measurement, where available, has implications for the differential diagnosis of hypophosphatemia syndromes and, potentially, treatment monitoring. Newer therapeutic modalities include calcium sensing receptor modulation (cinacalcet) and biological molecules targeting FGF23 or its receptors. Their long-term effects must be compared with those of conventional treatments.
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Affiliation(s)
- Martin Bitzan
- Department of Pediatrics, The Montreal Children's Hospital, McGill University Health Centre, 1001 Boulevard Décarie, Room B RC.6164, Montreal, Quebec H4A 3J1, Canada.
| | - Paul R Goodyer
- The Research Institute of the McGill University Health Centre, 1001 Boulevard Décarie, Room EM1.2232, Montreal, Quebec H4A3J1, Canada
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17
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Zhang Q, Xiao K, Paredes JM, Mamonova T, Sneddon WB, Liu H, Wang D, Li S, McGarvey JC, Uehling D, Al-Awar R, Joseph B, Jean-Alphonse F, Orte A, Friedman PA. Parathyroid hormone initiates dynamic NHERF1 phosphorylation cycling and conformational changes that regulate NPT2A-dependent phosphate transport. J Biol Chem 2019; 294:4546-4571. [PMID: 30696771 PMCID: PMC6433080 DOI: 10.1074/jbc.ra119.007421] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Revised: 01/25/2019] [Indexed: 12/30/2022] Open
Abstract
Na+-H+ exchanger regulatory factor-1 (NHERF1) is a PDZ protein that scaffolds membrane proteins, including sodium-phosphate co-transport protein 2A (NPT2A) at the plasma membrane. NHERF1 is a phosphoprotein with 40 Ser and Thr residues. Here, using tandem MS analysis, we characterized the sites of parathyroid hormone (PTH)-induced NHERF1 phosphorylation and identified 10 high-confidence phosphorylation sites. Ala replacement at Ser46, Ser162, Ser181, Ser269, Ser280, Ser291, Thr293, Ser299, and Ser302 did not affect phosphate uptake, but S290A substitution abolished PTH-dependent phosphate transport. Unexpectedly, Ser290 was rapidly dephosphorylated and rephosphorylated after PTH stimulation, and we found that protein phosphatase 1α (PP1α), which binds NHERF1 through a conserved VxF/W PP1 motif, dephosphorylates Ser290 Mutating 257VPF259 eliminated PP1 binding and blunted dephosphorylation. Tautomycetin blocked PP1 activity and abrogated PTH-sensitive phosphate transport. Using fluorescence lifetime imaging (FLIM), we observed that PTH paradoxically and transiently elevates intracellular phosphate. Added phosphate blocked PP1α-mediated Ser290 dephosphorylation of recombinant NHERF1. Hydrogen-deuterium exchange MS revealed that β-sheets in NHERF1's PDZ2 domain display lower deuterium uptake than those in the structurally similar PDZ1, implying that PDZ1 is more cloistered. Dephosphorylated NHERF1 exhibited faster exchange at C-terminal residues suggesting that NHERF1 dephosphorylation precedes Ser290 rephosphorylation. Our results show that PP1α and NHERF1 form a holoenzyme and that a multiprotein kinase cascade involving G protein-coupled receptor kinase 6A controls the Ser290 phosphorylation status of NHERF1 and regulates PTH-sensitive, NPT2A-mediated phosphate uptake. These findings reveal how reversible phosphorylation modifies protein conformation and function and the biochemical mechanisms underlying PTH control of phosphate transport.
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Affiliation(s)
- Qiangmin Zhang
- From the Laboratory for GPCR Biology, Department of Pharmacology and Chemical Biology
| | - Kunhong Xiao
- From the Laboratory for GPCR Biology, Department of Pharmacology and Chemical Biology.,Vascular Medicine Institute, and.,Biomedical Mass Spectrometry Center, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261
| | - José M Paredes
- the Department of Physical Chemistry, Faculty of Pharmacy, University of Granada, 18071-Granada, Spain
| | - Tatyana Mamonova
- From the Laboratory for GPCR Biology, Department of Pharmacology and Chemical Biology
| | - W Bruce Sneddon
- From the Laboratory for GPCR Biology, Department of Pharmacology and Chemical Biology
| | - Hongda Liu
- From the Laboratory for GPCR Biology, Department of Pharmacology and Chemical Biology
| | - Dawei Wang
- From the Laboratory for GPCR Biology, Department of Pharmacology and Chemical Biology
| | - Sheng Li
- the Department of Medicine, University of California San Diego, La Jolla, California 92093, and
| | - Jennifer C McGarvey
- From the Laboratory for GPCR Biology, Department of Pharmacology and Chemical Biology
| | - David Uehling
- the Department of Drug Discovery, Ontario Institute for Cancer Research, Toronto, Ontario M5G 0A3, Canada
| | - Rima Al-Awar
- the Department of Drug Discovery, Ontario Institute for Cancer Research, Toronto, Ontario M5G 0A3, Canada
| | - Babu Joseph
- the Department of Drug Discovery, Ontario Institute for Cancer Research, Toronto, Ontario M5G 0A3, Canada
| | | | - Angel Orte
- the Department of Physical Chemistry, Faculty of Pharmacy, University of Granada, 18071-Granada, Spain
| | - Peter A Friedman
- From the Laboratory for GPCR Biology, Department of Pharmacology and Chemical Biology, .,Department of Structural Biology
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18
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Abstract
Our understanding of the regulation of phosphate balance has benefited tremendously from the molecular identification and characterization of genetic defects leading to a number of rare inherited or acquired disorders affecting phosphate homeostasis. The identification of the key phosphate-regulating hormone, fibroblast growth factor 23 (FGF23), as well as other molecules that control its production, such as the glycosyltransferase GALNT3, the endopeptidase PHEX, and the matrix protein DMP1, and molecules that function as downstream effectors of FGF23 such as the longevity factor Klotho and the phosphate transporters NPT2a and NPT2c, has permitted us to understand the complex interplay that exists between the kidneys, bone, parathyroid, and gut. Such insights from genetic disorders have allowed not only the design of potent targeted treatment of FGF23-dependent hypophosphatemic conditions, but also provide clinically relevant observations related to the dysregulation of mineral ion homeostasis in health and disease.
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Affiliation(s)
- Marta Christov
- Division of Nephrology, Department of Medicine, New York Medical College, Valhalla, NY, USA
| | - Harald Jüppner
- Endocrine Unit and Pediatric Nephrology Unit, Massachusetts General Hospital, Boston, MA, USA; Harvard Medical School, Boston, MA, USA.
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19
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Hernando N, Wagner CA. Mechanisms and Regulation of Intestinal Phosphate Absorption. Compr Physiol 2018; 8:1065-1090. [PMID: 29978897 DOI: 10.1002/cphy.c170024] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
States of hypo- and hyperphosphatemia have deleterious consequences including rickets/osteomalacia and renal/cardiovascular disease, respectively. Therefore, the maintenance of appropriate plasma levels of phosphate is an essential requirement for health. This control is executed by the collaborative action of intestine and kidney whose capacities to (re)absorb phosphate are regulated by a number of hormonal and metabolic factors, among them parathyroid hormone, fibroblast growth factor 23, 1,25(OH)2 vitamin D3 , and dietary phosphate. The molecular mechanisms responsible for the transepithelial transport of phosphate across enterocytes are only partially understood. Indeed, whereas renal reabsorption entirely relies on well-characterized active transport mechanisms of phosphate across the renal proximal epithelia, intestinal absorption proceeds via active and passive mechanisms, with the molecular identity of the passive component still unknown. The active absorption of phosphate depends mostly on the activity and expression of the sodium-dependent phosphate cotransporter NaPi-IIb (SLC34A2), which is highly regulated by many of the factors, mentioned earlier. Physiologically, the contribution of NaPi-IIb to the maintenance of phosphate balance appears to be mostly relevant during periods of low phosphate availability. Therefore, its role in individuals living in industrialized societies with high phosphate intake is probably less relevant. Importantly, small increases in plasma phosphate, even within normal range, associate with higher risk of cardiovascular disease. Therefore, therapeutic approaches to treat hyperphosphatemia, including dietary phosphate restriction and phosphate binders, aim at reducing intestinal absorption. Here we review the current state of research in the field. © 2017 American Physiological Society. Compr Physiol 8:1065-1090, 2018.
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Affiliation(s)
- Nati Hernando
- National Center for Competence in Research NCCR Kidney.CH, Institute of Physiology, University Zurich-Irchel, Zurich, Switzerland
| | - Carsten A Wagner
- National Center for Competence in Research NCCR Kidney.CH, Institute of Physiology, University Zurich-Irchel, Zurich, Switzerland
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20
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Bergsland KJ, Coe FL, Parks JH, Asplin JR, Worcester EM. Evidence for a role of PDZ domain-containing proteins to mediate hypophosphatemia in calcium stone formers. Nephrol Dial Transplant 2018; 33:759-770. [PMID: 29126251 DOI: 10.1093/ndt/gfx284] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Accepted: 08/29/2017] [Indexed: 01/26/2023] Open
Abstract
Background Hypophosphatemia (HYP) is common among calcium stone formers (SFs) and in rare cases is associated with mutations in sodium-phosphate cotransporters or in Na+/H+ exchanger regulatory factor 1 (NHERF1), but the majority of cases are unexplained. We hypothesized that reduced sodium-phosphate cotransporter activity mediated via NHERF1 or a similar PDZ domain-containing protein, causes HYP. If so, other transport activities controlled by NHERF1, such as NHE3 and URAT1, might be reduced in HYP. Methods To test this idea, we analyzed two large but separate sets of 24-h urine samples and paired serums of 2700 SFs from the University of Chicago and 11 073 SFs from Litholink, a national laboratory. Patients were divided into quintiles based on serum phosphate. Results Males were more common in the lowest phosphate tiles in both datasets. Phosphate excretion did not vary across the quintiles, excluding diet as a cause of HYP. Tubule maximum (Tm) phosphate per unit glomerular filtration rate decreased and fractional excretion increased with decreasing phosphate quintiles, indicating reduced tubule phosphate reabsorption was responsible for HYP. Urine pH and serum chloride increased with decreasing serum phosphate, suggesting a coordinate change in NHE3 activity. Serum uric acid and Tm uric acid decreased significantly with decreasing serum phosphate, while uric acid excretion did not vary. Conclusion. HYP in SFs results from decreased tubule phosphate reabsorption and, being associated with related changes in other proximal tubule transporters, may arise from alterations in or signaling to PDZ-containing proteins.
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Affiliation(s)
| | - Fredric L Coe
- Department of Medicine, University of Chicago, Chicago, IL, USA
| | - Joan H Parks
- Department of Medicine, University of Chicago, Chicago, IL, USA
| | - John R Asplin
- Litholink Corporation, Laboratory Corporation of America Holdings, Chicago, IL, USA
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21
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Richter B, Faul C. FGF23 Actions on Target Tissues-With and Without Klotho. Front Endocrinol (Lausanne) 2018; 9:189. [PMID: 29770125 PMCID: PMC5940753 DOI: 10.3389/fendo.2018.00189] [Citation(s) in RCA: 127] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Accepted: 04/06/2018] [Indexed: 12/11/2022] Open
Abstract
Fibroblast growth factor (FGF) 23 is a phosphaturic hormone whose physiologic actions on target tissues are mediated by FGF receptors (FGFR) and klotho, which functions as a co-receptor that increases the binding affinity of FGF23 for FGFRs. By stimulating FGFR/klotho complexes in the kidney and parathyroid gland, FGF23 reduces renal phosphate uptake and secretion of parathyroid hormone, respectively, thereby acting as a key regulator of phosphate metabolism. Recently, it has been shown that FGF23 can also target cell types that lack klotho. This unconventional signaling event occurs in an FGFR-dependent manner, but involves other downstream signaling pathways than in "classic" klotho-expressing target organs. It appears that klotho-independent signaling mechanisms are only activated in the presence of high FGF23 concentrations and result in pathologic cellular changes. Therefore, it has been postulated that massive elevations in circulating levels of FGF23, as found in patients with chronic kidney disease, contribute to associated pathologies by targeting cells and tissues that lack klotho. This includes the induction of cardiac hypertrophy and fibrosis, the elevation of inflammatory cytokine expression in the liver, and the inhibition of neutrophil recruitment. Here, we describe the signaling and cellular events that are caused by FGF23 in tissues lacking klotho, and we discuss FGF23's potential role as a hormone with widespread pathologic actions. Since the soluble form of klotho can function as a circulating co-receptor for FGF23, we also discuss the potential inhibitory effects of soluble klotho on FGF23-mediated signaling which might-at least partially-underlie the pleiotropic tissue-protective functions of klotho.
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Abstract
Rickets is a bone disease associated with abnormal serum calcium and phosphate levels. The clinical presentation is heterogeneous and depends on the age of onset and pathogenesis but includes bowing deformities of the legs, short stature and widening of joints. The disorder can be caused by nutritional deficiencies or genetic defects. Mutations in genes encoding proteins involved in vitamin D metabolism or action, fibroblast growth factor 23 (FGF23) production or degradation, renal phosphate handling or bone mineralization have been identified. The prevalence of nutritional rickets has substantially declined compared with the prevalence 200 years ago, but the condition has been re-emerging even in some well-resourced countries; prematurely born infants or breastfed infants who have dark skin types are particularly at risk. Diagnosis is usually established by medical history, physical examination, biochemical tests and radiography. Prevention is possible only for nutritional rickets and includes supplementation or food fortification with calcium and vitamin D either alone or in combination with sunlight exposure. Treatment of typical nutritional rickets includes calcium and/or vitamin D supplementation, although instances infrequently occur in which phosphate repletion may be necessary. Management of heritable types of rickets associated with defects in vitamin D metabolism or activation involves the administration of vitamin D metabolites. Oral phosphate supplementation is usually indicated for FGF23-independent phosphopenic rickets, whereas the conventional treatment of FGF23-dependent types of rickets includes a combination of phosphate and activated vitamin D; an anti-FGF23 antibody has shown promising results and is under further study.
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23
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Policastro LJ, Saggi SJ, Goldfarb DS, Weiss JP. Personalized Intervention in Monogenic Stone Formers. J Urol 2017; 199:623-632. [PMID: 29061541 DOI: 10.1016/j.juro.2017.09.143] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/19/2017] [Indexed: 12/16/2022]
Abstract
PURPOSE Treatment of a first-time renal stone consists of acute management followed by medical efforts to prevent stone recurrence. Although nephrolithiasis is roughly 50% heritable, the presence of a family history usually does not affect treatment since most stone disease is regarded as polygenic, ie not attributable to a single gene. Recent evidence has suggested that single mutations could be responsible for a larger proportion of renal stones than previously thought. This intriguing possibility holds the potential to change the management paradigm in stone prevention from metabolically directed therapy to more specific approaches informed by genetic screening and testing. This review synthesizes new findings concerning monogenic kidney stone disease, and provides a concise and clinically useful reference for monogenic causes. It is expected that increased awareness of these etiologies will lead to increased use of genetic testing in recurrent stone formers and further research into the prevalence of monogenic stone disease. MATERIALS AND METHODS We assembled a complete list of genes known to cause or influence nephrolithiasis based on recent reviews and commentaries. We then comprehensively searched PubMed® and Google Scholar™ for all research on each gene having a pertinent role in nephrolithiasis. We determined which genes could be considered monogenic causes of nephrolithiasis. One gene, ALPL, was excluded since nephrolithiasis is a relatively minor aspect of the disorder associated with the gene (hypophosphatasia). We summarized selected studies and assembled clinically relevant details. RESULTS A total of 27 genes were reviewed in terms of recent findings, mode of inheritance of stone disease, known or supposed prevalence of mutations in the general population of stone patients and specific therapies or considerations. CONCLUSIONS There is a distinct opportunity for increased use of genetic testing to improve the lives of pediatric and adult stone patients. Several genes first reported in association with rare disease may be loci for novel mutations, heterozygous disease and forme frustes as causes of stones in the broader population. Cases of idiopathic nephrolithiasis should be considered as potentially having a monogenic basis.
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Affiliation(s)
- Lucas J Policastro
- Department of Medicine, SUNY Downstate Medical Center, Brooklyn, New York.
| | - Subodh J Saggi
- Department of Nephrology, SUNY Downstate Medical Center, Brooklyn, New York
| | - David S Goldfarb
- Nephrology Section, NY Harbor VA Medical Center, New York, New York; Nephrology Division, New York University School of Medicine, New York, New York
| | - Jeffrey P Weiss
- Department of Urology, SUNY Downstate Medical Center, Brooklyn, New York; Urology Service, NY Harbor VA Medical Center, New York, New York
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24
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Justet A, Joannes A, Besnard V, Marchal-Sommé J, Jaillet M, Bonniaud P, Sallenave JM, Solhonne B, Castier Y, Mordant P, Mal H, Cazes A, Borie R, Mailleux AA, Crestani B. FGF9 prevents pleural fibrosis induced by intrapleural adenovirus injection in mice. Am J Physiol Lung Cell Mol Physiol 2017; 313:L781-L795. [PMID: 28729349 DOI: 10.1152/ajplung.00508.2016] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Revised: 07/10/2017] [Accepted: 07/10/2017] [Indexed: 12/12/2022] Open
Abstract
Fibroblast growth factor 9 (FGF9) is necessary for fetal lung development and is expressed by epithelium and mesothelium. We evaluated the role of FGF9 overexpression on adenoviral-induced pleural injury in vivo and determined the biological effects of FGF9 on mesothelial cells in vitro. We assessed the expression of FGF9 and FGF receptors by mesothelial cells in both human and mouse lungs. Intrapleural injection of an adenovirus expressing human FGF9 (AdFGF9) or a control adenovirus (AdCont) was performed. Mice were euthanized at days 3, 5, and 14 Expression of FGF9 and markers of inflammation and myofibroblastic differentiation was studied by qPCR and immunohistochemistry. In vitro, rat mesothelial cells were stimulated with FGF9 (20 ng/ml), and we assessed its effect on proliferation, survival, migration, and differentiation. FGF9 was expressed by mesothelial cells in human idiopathic pulmonary fibrosis. FGF receptors, mainly FGFR3, were expressed by mesothelial cells in vivo in humans and mice. AdCont instillation induced diffuse pleural thickening appearing at day 5, maximal at day 14 The altered pleura cells strongly expressed α-smooth muscle actin and collagen. AdFGF9 injection induced maximal FGF9 expression at day 5 that lasted until day 14 FGF9 overexpression prevented pleural thickening, collagen and fibronectin accumulation, and myofibroblastic differentiation of mesothelial cells. In vitro, FGF9 decreased mesothelial cell migration and inhibited the differentiating effect of transforming growth factor-β1. We conclude that FGF9 has a potential antifibrotic effect on mesothelial cells.
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Affiliation(s)
- Aurélien Justet
- Institut National de la Santé et de la Recherche Médicale U1152, Paris, France.,Département Hospitalo-Universitaire Fibrosis Inflammation and Remodeling (DHU FIRE), Paris, France.,Labex Inflamex, Paris, France.,Université Paris Diderot, Sorbonne Paris Cité, Paris, France.,Assistance Publique-Hôpitaux de Paris, Hôpital Bichat, Service de Pneumologie A, Paris, France
| | - Audrey Joannes
- Institut National de la Santé et de la Recherche Médicale U1152, Paris, France.,Département Hospitalo-Universitaire Fibrosis Inflammation and Remodeling (DHU FIRE), Paris, France.,Labex Inflamex, Paris, France.,Université Paris Diderot, Sorbonne Paris Cité, Paris, France
| | - Valérie Besnard
- Institut National de la Santé et de la Recherche Médicale U1152, Paris, France.,Département Hospitalo-Universitaire Fibrosis Inflammation and Remodeling (DHU FIRE), Paris, France.,Labex Inflamex, Paris, France.,Université Paris Diderot, Sorbonne Paris Cité, Paris, France
| | - Joëlle Marchal-Sommé
- Institut National de la Santé et de la Recherche Médicale U1152, Paris, France.,Département Hospitalo-Universitaire Fibrosis Inflammation and Remodeling (DHU FIRE), Paris, France.,Labex Inflamex, Paris, France.,Université Paris Diderot, Sorbonne Paris Cité, Paris, France
| | - Madeleine Jaillet
- Institut National de la Santé et de la Recherche Médicale U1152, Paris, France.,Département Hospitalo-Universitaire Fibrosis Inflammation and Remodeling (DHU FIRE), Paris, France.,Labex Inflamex, Paris, France.,Université Paris Diderot, Sorbonne Paris Cité, Paris, France
| | - Philipe Bonniaud
- Institut National de la Santé et de la Recherche Médicale U866, Université de Bourgogne, Dijon, France
| | - Jean Michel Sallenave
- Institut National de la Santé et de la Recherche Médicale U1152, Paris, France.,Département Hospitalo-Universitaire Fibrosis Inflammation and Remodeling (DHU FIRE), Paris, France.,Labex Inflamex, Paris, France.,Université Paris Diderot, Sorbonne Paris Cité, Paris, France
| | - Brigitte Solhonne
- Institut National de la Santé et de la Recherche Médicale U1152, Paris, France.,Département Hospitalo-Universitaire Fibrosis Inflammation and Remodeling (DHU FIRE), Paris, France.,Labex Inflamex, Paris, France.,Université Paris Diderot, Sorbonne Paris Cité, Paris, France
| | - Yves Castier
- Institut National de la Santé et de la Recherche Médicale U1152, Paris, France.,Département Hospitalo-Universitaire Fibrosis Inflammation and Remodeling (DHU FIRE), Paris, France.,Labex Inflamex, Paris, France.,Université Paris Diderot, Sorbonne Paris Cité, Paris, France.,Assistance Publique-Hôpitaux de Paris, Hôpital Bichat, Service de Chirurgie Thoracique et Vasculaire, Paris, France
| | - Pierre Mordant
- Institut National de la Santé et de la Recherche Médicale U1152, Paris, France.,Département Hospitalo-Universitaire Fibrosis Inflammation and Remodeling (DHU FIRE), Paris, France.,Labex Inflamex, Paris, France.,Université Paris Diderot, Sorbonne Paris Cité, Paris, France.,Assistance Publique-Hôpitaux de Paris, Hôpital Bichat, Service de Chirurgie Thoracique et Vasculaire, Paris, France
| | - Hervé Mal
- Institut National de la Santé et de la Recherche Médicale U1152, Paris, France.,Département Hospitalo-Universitaire Fibrosis Inflammation and Remodeling (DHU FIRE), Paris, France.,Labex Inflamex, Paris, France.,Université Paris Diderot, Sorbonne Paris Cité, Paris, France.,Assistance Publique-Hôpitaux de Paris, Hôpital Bichat, Service de Pneumologie et Transplantation, Paris, France; and
| | - Aurélie Cazes
- Institut National de la Santé et de la Recherche Médicale U1152, Paris, France.,Département Hospitalo-Universitaire Fibrosis Inflammation and Remodeling (DHU FIRE), Paris, France.,Labex Inflamex, Paris, France.,Université Paris Diderot, Sorbonne Paris Cité, Paris, France.,Assistance Publique-Hôpitaux de Paris, Hôpital Bichat, Département d'Anatomie Pathologique, Paris, France
| | - Raphael Borie
- Institut National de la Santé et de la Recherche Médicale U1152, Paris, France.,Département Hospitalo-Universitaire Fibrosis Inflammation and Remodeling (DHU FIRE), Paris, France.,Labex Inflamex, Paris, France.,Université Paris Diderot, Sorbonne Paris Cité, Paris, France.,Assistance Publique-Hôpitaux de Paris, Hôpital Bichat, Service de Pneumologie A, Paris, France
| | - Arnaud A Mailleux
- Institut National de la Santé et de la Recherche Médicale U1152, Paris, France.,Département Hospitalo-Universitaire Fibrosis Inflammation and Remodeling (DHU FIRE), Paris, France.,Labex Inflamex, Paris, France.,Université Paris Diderot, Sorbonne Paris Cité, Paris, France
| | - Bruno Crestani
- Institut National de la Santé et de la Recherche Médicale U1152, Paris, France; .,Département Hospitalo-Universitaire Fibrosis Inflammation and Remodeling (DHU FIRE), Paris, France.,Labex Inflamex, Paris, France.,Université Paris Diderot, Sorbonne Paris Cité, Paris, France.,Assistance Publique-Hôpitaux de Paris, Hôpital Bichat, Service de Pneumologie A, Paris, France
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25
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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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