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Thomas L, Dissanayake LV, Tahmasbi M, Staruschenko A, Al-Masri S, Dominguez Rieg JA, Rieg T. Vitamin D 3 suppresses Npt2c abundance and differentially modulates phosphate and calcium homeostasis in Npt2a knockout mice. Sci Rep 2024; 14:16997. [PMID: 39043847 PMCID: PMC11266651 DOI: 10.1038/s41598-024-67839-4] [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: 03/09/2024] [Accepted: 07/16/2024] [Indexed: 07/25/2024] Open
Abstract
Vitamin D3 is clinically used for the treatment of vitamin D3 deficiency or osteoporosis, partially because of its role in regulating phosphate (Pi) and calcium (Ca2+) homeostasis. The renal sodium-phosphate cotransporter 2a (Npt2a) plays an important role in Pi homeostasis; however, the role of vitamin D3 in hypophosphatemia has never been investigated. We administered vehicle or vitamin D3 to wild-type (WT) mice or hypophosphatemic Npt2a-/- mice. In contrast to WT mice, vitamin D3 treatment increased plasma Pi levels in Npt2a-/- mice, despite similar levels of reduced parathyroid hormone and increased fibroblast growth factor 23. Plasma Ca2+ was increased ~ twofold in both genotypes. Whereas WT mice were able to increase urinary Pi and Ca2+/creatinine ratios, in Npt2a-/- mice, Pi/creatinine was unchanged and Ca2+/creatinine drastically decreased, coinciding with the highest kidney Ca2+ content, highest plasma creatinine, and greatest amount of nephrocalcinosis. In Npt2a-/- mice, vitamin D3 treatment completely diminished Npt2c abundance, so that mice resembled Npt2a/c double knockout mice. Abundance of intestinal Npt2b and claudin-3 (tight junctions protein) were reduced in Npt2a-/- only, the latter might facilitate the increase in plasma Pi in Npt2a-/- mice. Npt2a might function as regulator between renal Ca2+ excretion and reabsorption in response to vitamin D3.
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Affiliation(s)
- Linto Thomas
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, FL, USA
- James A. Haley Veterans' Hospital, Tampa, FL, USA
| | - Lashodya V Dissanayake
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, FL, USA
| | - Maryam Tahmasbi
- Department of Pathology and Cell Biology, University of South Florida, Tampa, FL, USA
| | - Alexander Staruschenko
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, FL, USA
- James A. Haley Veterans' Hospital, Tampa, FL, USA
- Hypertension and Kidney Research Center, University of South Florida, Tampa, FL, USA
| | - Sima Al-Masri
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, FL, USA
| | - Jessica A Dominguez Rieg
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, FL, USA
- James A. Haley Veterans' Hospital, Tampa, FL, USA
- Hypertension and Kidney Research Center, University of South Florida, Tampa, FL, USA
| | - Timo Rieg
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, FL, USA.
- James A. Haley Veterans' Hospital, Tampa, FL, USA.
- Hypertension and Kidney Research Center, University of South Florida, Tampa, FL, USA.
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Zhang J, Che T, Wang L, Sun W, Zhao J, Chen J, Liu Y, Pu Q, Zhang Y, Li J, Li Z, Zhu Z, Fu Q, Wang X, Yuan J. Proteomics coupled transcriptomics reveals Slc34a1 and Slc34a3 downregulation as potential features of nephrotoxin-induced acute kidney injury. J Proteomics 2024; 302:105203. [PMID: 38782357 DOI: 10.1016/j.jprot.2024.105203] [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: 08/07/2023] [Revised: 05/11/2024] [Accepted: 05/20/2024] [Indexed: 05/25/2024]
Abstract
Acute kidney injury (AKI) stands as a prevalent and economically burdensome condition worldwide, yet its complex molecular mechanisms remain incompletely understood. To address this gap, our study employs a multifaceted approach, combining mass spectrometry and RNA sequencing technologies, to elucidate the intricate molecular landscape underlying nephrotoxin-induced AKI in mice by cisplatin- and LPS-induced. By examining the protein and RNA expression profiles, we aimed to uncover novel insights into the pathogenesis of AKI and identify potential diagnostic and therapeutic targets. Our results demonstrate significant down-regulation of Slc34a1 and Slc34a3, shedding light on their crucial roles in AKI pathology and highlighting their promise as actionable targets for diagnosis and treatment. This comprehensive analysis not only enhances our understanding of AKI pathophysiology but also offers valuable avenues for the development of targeted interventions to mitigate its clinical impact. SIGNIFICANCE: Nephrotoxicity acute kidney injury (AKI) is a common clinical condition whose pathogenesis is the process by which some drugs, chemicals or other factors cause damage to the kidneys, resulting in impaired kidney function. Although it has been proved that different nephrotoxic substances can affect the kidney through different pathways, whether they have a commonality has not been registered. Here, we combined transcriptomics and proteomics to study the molecular mechanism of LPS and cisplatin-induced nephrotoxic acute kidney injury finding that the down-regulation of Slc34a1 and Slc34a3 may be a critical link in nephrotoxic acute kidney injury, which can be used as a marker for its early diagnosis.
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Affiliation(s)
- Junying Zhang
- Chongqing Key Laboratory of High Active Traditional Chinese Drug Delivery System, Chongqing Engineering Research Center of Pharmaceutical Sciences, Chongqing Medical and Pharmaceutical College, Chongqing 401331, China; College of Pharmacy, Chongqing Medical University, Chongqing 400016, China
| | - Tiantian Che
- Chongqing Nanan District Center for Diseases Control and Prevention, Chongqing 401336, China
| | - Liting Wang
- Biomedical Analysis Center, Army Medical University, Chongqing 400038, China
| | - Wei Sun
- Biomedical Analysis Center, Army Medical University, Chongqing 400038, China
| | - Jing Zhao
- Biomedical Analysis Center, Army Medical University, Chongqing 400038, China
| | - Jiajia Chen
- Biomedical Analysis Center, Army Medical University, Chongqing 400038, China
| | - Yang Liu
- Biomedical Analysis Center, Army Medical University, Chongqing 400038, China
| | - Qi Pu
- Biomedical Analysis Center, Army Medical University, Chongqing 400038, China
| | - Yu Zhang
- Biomedical Analysis Center, Army Medical University, Chongqing 400038, China
| | - Jiani Li
- Hepato-Pancreato-Biliary Surgery, Peking University Shenzhen Hospital, Shenzhen 518036, China
| | - Zhangfu Li
- Hepato-Pancreato-Biliary Surgery, Peking University Shenzhen Hospital, Shenzhen 518036, China; Hepato-Pancreato-Biliary Surgery, Peking University Shenzhen Hospital, Shenzhen Peking University-The Hong Kong University of Science and Technology Medical Center, Guangdong province, Shenzhen 518036, China
| | - Zhaojing Zhu
- Chongqing Key Laboratory of High Active Traditional Chinese Drug Delivery System, Chongqing Engineering Research Center of Pharmaceutical Sciences, Chongqing Medical and Pharmaceutical College, Chongqing 401331, China.
| | - Qihuan Fu
- Chongqing Key Laboratory of Translational Research for Cancer Metastasis and Individualized Treatment, Chongqing University Cancer Hospital, Chongqing 400030, China.
| | - Xiaoyang Wang
- Biomedical Analysis Center, Army Medical University, Chongqing 400038, China..
| | - Jiangbei Yuan
- Hepato-Pancreato-Biliary Surgery, Peking University Shenzhen Hospital, Shenzhen 518036, China; Hepato-Pancreato-Biliary Surgery, Peking University Shenzhen Hospital, Shenzhen Peking University-The Hong Kong University of Science and Technology Medical Center, Guangdong province, Shenzhen 518036, China.; Center for General Practice Medicine, Department of Infectious Diseases, Zhejiang Provincial People's Hospital(Affiliated People's Hospital), Hangzhou Medical College, Hangzhou 310014, Zhejiang, China; Department of Infectious Diseases, Affiliated Banan Hospital of Chongqing Medical University, Chongqing 400016, China.
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3
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Abstract
Inorganic phosphate (Pi) is an essential component of many biologically important molecules such as DNA, RNA, ATP, phospholipids, or apatite. It is required for intracellular phosphorylation signaling events and acts as pH buffer in intra- and extracellular compartments. Intestinal absorption, uptake into cells, and renal reabsorption depend on a set of different phosphate transporters from the SLC20 (PiT transporters) and SLC34 (NaPi transporters) gene families. The physiological relevance of these transporters is evident from rare monogenic disorders in humans affecting SLC20A2 (Fahr's disease, basal ganglia calcification), SLC34A1 (idiopathic infantile hypercalcemia), SLC34A2 (pulmonary alveolar microlithiasis), and SLC34A3 (hereditary hypophosphatemic rickets with hypercalciuria). SLC34 transporters are inhibited by millimolar concentrations of phosphonoformic acid or arsenate while SLC20 are relatively resistant to these compounds. More recently, a series of more specific and potent drugs have been developed to target SLC34A2 to reduce intestinal Pi absorption and to inhibit SLC34A1 and/or SLC34A3 to increase renal Pi excretion in patients with renal disease and incipient hyperphosphatemia. Also, SLC20 inhibitors have been developed with the same intention. Some of these substances are currently undergoing preclinical and clinical testing. Tenapanor, a non-absorbable Na+/H+-exchanger isoform 3 inhibitor, reduces intestinal Pi absorption likely by indirectly acting on the paracellular pathway for Pi and has been tested in several phase III trials for reducing Pi overload in patients with renal insufficiency and dialysis.
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Affiliation(s)
- Carsten A Wagner
- Institute of Physiology, University of Zurich, Zurich, Switzerland.
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4
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Lederer E. Understanding renal phosphate handling: unfinished business. Curr Opin Nephrol Hypertens 2023; 32:394-400. [PMID: 37070493 DOI: 10.1097/mnh.0000000000000889] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/19/2023]
Abstract
PURPOSE OF REVIEW The purpose of this review is to highlight the publications from the prior 12-18 months that have contributed significant advances in the field of renal phosphate handling. RECENT FINDINGS The discoveries include new mechanisms for the trafficking and expression of the sodium phosphate cotransporters; direct link between phosphate uptake and intracellular metabolic pathways; interdependence between proximal tubule transporters; and the persistent renal expression of phosphate transporters in chronic kidney disease. SUMMARY Discovery of new mechanisms for trafficking and regulation of expression of phosphate transporters suggest new targets for the therapy of disorders of phosphate homeostasis. Demonstration of stimulation of glycolysis by phosphate transported into a proximal tubule cell expands the scope of function for the type IIa sodium phosphate transporter from merely a mechanism to reclaim filtered phosphate to a regulator of cell metabolism. This observation opens the door to new therapies for preserving kidney function through alteration in transport. The evidence for persistence of active renal phosphate transport even with chronic kidney disease upends our assumptions of how expression of these transporters is regulated, suggests the possibility of alternative functions for the transporters, and raises the possibility of new therapies for phosphate retention.
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Affiliation(s)
- Eleanor Lederer
- Assistant Chief Medical Services, Co-Director NODES Program, Charles and Jane Pak Center for Mineral Metabolism and Clinical Research, Division of Nephrology, University of Texas Southwestern Medical Center, Medical Services for Research, NODES Program, VA North Texas Healthcare Services, Dallas, Texas, USA
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Zhou W, Simic P, Zhou IY, Caravan P, Vela Parada X, Wen D, Washington OL, Shvedova M, Pierce KA, Clish CB, Mannstadt M, Kobayashi T, Wein MN, Jüppner H, Rhee EP. Kidney glycolysis serves as a mammalian phosphate sensor that maintains phosphate homeostasis. J Clin Invest 2023; 133:e164610. [PMID: 36821389 PMCID: PMC10104895 DOI: 10.1172/jci164610] [Citation(s) in RCA: 28] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Accepted: 02/21/2023] [Indexed: 02/24/2023] Open
Abstract
How phosphate levels are detected in mammals is unknown. The bone-derived hormone fibroblast growth factor 23 (FGF23) lowers blood phosphate levels by reducing kidney phosphate reabsorption and 1,25(OH)2D production, but phosphate does not directly stimulate bone FGF23 expression. Using PET scanning and LC-MS, we found that phosphate increases kidney-specific glycolysis and synthesis of glycerol-3-phosphate (G-3-P), which then circulates to bone to trigger FGF23 production. Further, we found that G-3-P dehydrogenase 1 (Gpd1), a cytosolic enzyme that synthesizes G-3-P and oxidizes NADH to NAD+, is required for phosphate-stimulated G-3-P and FGF23 production and prevention of hyperphosphatemia. In proximal tubule cells, we found that phosphate availability is substrate-limiting for glycolysis and G-3-P production and that increased glycolysis and Gpd1 activity are coupled through cytosolic NAD+ recycling. Finally, we show that the type II sodium-dependent phosphate cotransporter Npt2a, which is primarily expressed in the proximal tubule, conferred kidney specificity to phosphate-stimulated G-3-P production. Importantly, exogenous G-3-P stimulated FGF23 production when Npt2a or Gpd1 were absent, confirming that it was the key circulating factor downstream of glycolytic phosphate sensing in the kidney. Together, these findings place glycolysis at the nexus of mineral and energy metabolism and identify a kidney-bone feedback loop that controls phosphate homeostasis.
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Affiliation(s)
- Wen Zhou
- Nephrology Division, Department of Medicine, and
- Endocrine Unit, Department of Medicine, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Petra Simic
- Nephrology Division, Department of Medicine, and
- Endocrine Unit, Department of Medicine, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Iris Y. Zhou
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, Massachusetts, USA
| | - Peter Caravan
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, Massachusetts, USA
| | - Xavier Vela Parada
- Nephrology Division, Department of Medicine, and
- Endocrine Unit, Department of Medicine, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Donghai Wen
- Nephrology Division, Department of Medicine, and
- Endocrine Unit, Department of Medicine, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Onica L. Washington
- Nephrology Division, Department of Medicine, and
- Endocrine Unit, Department of Medicine, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Maria Shvedova
- Endocrine Unit, Department of Medicine, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Kerry A. Pierce
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, USA
| | - Clary B. Clish
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, USA
| | - Michael Mannstadt
- Endocrine Unit, Department of Medicine, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Tatsuya Kobayashi
- Endocrine Unit, Department of Medicine, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Marc N. Wein
- Endocrine Unit, Department of Medicine, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Harald Jüppner
- Endocrine Unit, Department of Medicine, Massachusetts General Hospital, Boston, Massachusetts, USA
- Pediatric Nephrology Unit, Department of Pediatrics, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Eugene P. Rhee
- Nephrology Division, Department of Medicine, and
- Endocrine Unit, Department of Medicine, Massachusetts General Hospital, Boston, Massachusetts, USA
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Bollenbecker S, Heitman K, Czaya B, Easter M, Hirsch MJ, Vang S, Harris E, Helton ES, Barnes JW, Faul C, Krick S. Phosphate induces inflammation and exacerbates injury from cigarette smoke in the bronchial epithelium. Sci Rep 2023; 13:4898. [PMID: 36966182 PMCID: PMC10039898 DOI: 10.1038/s41598-023-32053-1] [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: 01/13/2023] [Accepted: 03/21/2023] [Indexed: 03/27/2023] Open
Abstract
An elevation in serum phosphate-also called hyperphosphatemia-is associated with reduced kidney function in chronic kidney disease (CKD). Reports show CKD patients are more likely to develop lung disease and have poorer kidney function that positively correlates with pulmonary obstruction. However, the underlying mechanisms are not well understood. Here, we report that two murine models of CKD, which both exhibit increased serum levels of phosphate and fibroblast growth factor (FGF) 23, a regulator of phosphate homeostasis, develop concomitant airway inflammation. Our in vitro studies point towards a similar increase of phosphate-induced inflammatory markers in human bronchial epithelial cells. FGF23 stimulation alone does not induce a proinflammatory response in the non-COPD bronchial epithelium and phosphate does not cause endogenous FGF23 release. Upregulation of the phosphate-induced proinflammatory cytokines is accompanied by activation of the extracellular-signal regulated kinase (ERK) pathway. Moreover, the addition of cigarette smoke extract (CSE) during phosphate treatments exacerbates inflammation as well as ERK activation, whereas co-treatment with FGF23 attenuates both the phosphate as well as the combined phosphate- and CS-induced inflammatory response, independent of ERK activation. Together, these data demonstrate a novel pathway that potentially explains pathological kidney-lung crosstalk with phosphate as a key mediator.
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Affiliation(s)
- Seth Bollenbecker
- Division of Pulmonary, Allergy and Critical Care Medicine, Department of Medicine, The University of Alabama at Birmingham, 1918 University Blvd, MCLM 718, Birmingham, AL, 35294, USA
| | - Kylie Heitman
- Section of Mineral Metabolism, Division of Nephrology, Department of Medicine, The University of Alabama at Birmingham, Birmingham, AL, USA
| | - Brian Czaya
- Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Molly Easter
- Division of Pulmonary, Allergy and Critical Care Medicine, Department of Medicine, The University of Alabama at Birmingham, 1918 University Blvd, MCLM 718, Birmingham, AL, 35294, USA
| | - Meghan June Hirsch
- Division of Pulmonary, Allergy and Critical Care Medicine, Department of Medicine, The University of Alabama at Birmingham, 1918 University Blvd, MCLM 718, Birmingham, AL, 35294, USA
| | - Shia Vang
- Division of Pulmonary, Allergy and Critical Care Medicine, Department of Medicine, The University of Alabama at Birmingham, 1918 University Blvd, MCLM 718, Birmingham, AL, 35294, USA
| | - Elex Harris
- Division of Pulmonary, Allergy and Critical Care Medicine, Department of Medicine, The University of Alabama at Birmingham, 1918 University Blvd, MCLM 718, Birmingham, AL, 35294, USA
| | - E Scott Helton
- Division of Pulmonary, Allergy and Critical Care Medicine, Department of Medicine, The University of Alabama at Birmingham, 1918 University Blvd, MCLM 718, Birmingham, AL, 35294, USA
| | - Jarrod W Barnes
- Division of Pulmonary, Allergy and Critical Care Medicine, Department of Medicine, The University of Alabama at Birmingham, 1918 University Blvd, MCLM 718, Birmingham, AL, 35294, USA
| | - Christian Faul
- Section of Mineral Metabolism, Division of Nephrology, Department of Medicine, The University of Alabama at Birmingham, Birmingham, AL, USA
| | - Stefanie Krick
- Division of Pulmonary, Allergy and Critical Care Medicine, Department of Medicine, The University of Alabama at Birmingham, 1918 University Blvd, MCLM 718, Birmingham, AL, 35294, USA.
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7
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Regulation of FGF23 production and phosphate metabolism by bone-kidney interactions. Nat Rev Nephrol 2023; 19:185-193. [PMID: 36624273 DOI: 10.1038/s41581-022-00665-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/30/2022] [Indexed: 01/11/2023]
Abstract
The bone-derived hormone fibroblast growth factor 23 (FGF23) functions in concert with parathyroid hormone (PTH) and the active vitamin D metabolite, 1,25(OH)2 vitamin D (1,25D), to control phosphate and calcium homeostasis. A rise in circulating levels of phosphate and 1,25D leads to FGF23 production in bone. Circulating FGF23 acts on the kidney by binding to FGF receptors and the co-receptor α-Klotho to promote phosphaturia and reduce circulating 1,25D levels. Various other biomolecules that are produced by the kidney, including lipocalin-2, glycerol 3-phosphate, 1-acyl lysophosphatidic acid and erythropoietin, are involved in the regulation of mineral metabolism via effects on FGF23 synthesis in bone. Understanding of the molecular mechanisms that control FGF23 synthesis in the bone and its bioactivity in the kidney has led to the identification of potential targets for novel interventions. Emerging approaches to target aberrant phosphate metabolism include small molecule inhibitors that directly bind FGF23 and prevent its interactions with FGF receptors and α-Klotho, FGF23 peptide fragments that act as competitive inhibitors of intact FGF23 and small molecule inhibitors of kidney sodium-phosphate cotransporters.
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Portales-Castillo I, Rieg T, Khalid SB, Nigwekar SU, Neyra JA. Physiopathology of Phosphate Disorders. ADVANCES IN KIDNEY DISEASE AND HEALTH 2023; 30:177-188. [PMID: 36868732 PMCID: PMC10565570 DOI: 10.1053/j.akdh.2022.12.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Revised: 12/24/2022] [Accepted: 12/29/2022] [Indexed: 03/05/2023]
Abstract
Intracellular phosphate is critical for cellular processes such as signaling, nucleic acid synthesis, and membrane function. Extracellular phosphate (Pi) is an important component of the skeleton. Normal levels of serum phosphate are maintained by the coordinated actions of 1,25-dihydroxyvitamin D3, parathyroid hormone and fibroblast growth factor-23, which intersect in the proximal tubule to control the reabsorption of phosphate via the sodium-phosphate cotransporters Npt2a and Npt2c. Furthermore, 1,25-dihydroxyvitamin D3 participates in the regulation of dietary phosphate absorption in the small intestine. Clinical manifestations associated with abnormal serum phosphate levels are common and occur as a result of genetic or acquired conditions affecting phosphate homeostasis. For example, chronic hypophosphatemia leads to osteomalacia in adults and rickets in children. Acute severe hypophosphatemia can affect multiple organs leading to rhabdomyolysis, respiratory dysfunction, and hemolysis. Patients with impaired kidney function, such as those with advanced CKD, have high prevalence of hyperphosphatemia, with approximately two-thirds of patients on chronic hemodialysis in the United States having serum phosphate levels above the recommended goal of 5.5 mg/dL, a cutoff associated with excess risk of cardiovascular complications. Furthermore, patients with advanced kidney disease and hyperphosphatemia (>6.5 mg/dL) have almost one-third excess risk of death than those with phosphate levels between 2.4 and 6.5 mg/dL. Given the complex mechanisms that regulate phosphate levels, the interventions to treat the various diseases associated with hypophosphatemia or hyperphosphatemia rely on the understanding of the underlying pathobiological mechanisms governing each patient condition.
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Affiliation(s)
- Ignacio Portales-Castillo
- Division of Nephrology, Department of Medicine, Massachusetts General Hospital, and Harvard Medical School, Boston, MA; Endocrine Unit, Massachusetts General Hospital, and Harvard Medical School, Boston, MA
| | - Timo Rieg
- Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, FL; James A. Haley Veterans' Hospital, Tampa, FL; Center for Hypertension and Kidney Research, University of South Florida, Tampa, FL
| | - Sheikh B Khalid
- Department of Internal Medicine, The Indus Hospital, Lahore Pakistan
| | - Sagar U Nigwekar
- Division of Nephrology, Department of Medicine, Massachusetts General Hospital, and Harvard Medical School, Boston, MA
| | - Javier A Neyra
- Department of Internal Medicine, Division of Nephrology, University of Alabama at Birmingham, Birmingham, AL.
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Sodium phosphate cotransporter 2a inhibitors: potential therapeutic uses. Curr Opin Nephrol Hypertens 2022; 31:486-492. [PMID: 35894284 PMCID: PMC9387751 DOI: 10.1097/mnh.0000000000000828] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
PURPOSE OF REVIEW Targeting sodium phosphate cotransporter 2a (Npt2a) offers a novel strategy for treating hyperphosphatemia in chronic kidney disease (CKD). Here we review recent studies on the efficacy of Npt2a inhibition, its plasma phosphate (Pi)-lowering effects, as well as potential "off-target" beneficial effects on cardiovascular consequences. RECENT FINDINGS Two novel Npt2a-selective inhibitors (PF-06869206 and BAY-767) have been developed. Pharmacological Npt2a inhibition shows a significant phosphaturic effect and consequently lowers plasma Pi and parathyroid hormone (PTH) levels regardless of CKD. However, plasma fibroblast growth factor 23 (FGF23), a master regulator of Pi homeostasis, shows inconsistent responses between these two inhibitors (no effect by PF-06869206 vs. reduction by BAY-767). In addition to the effects on Pi homeostasis, Npt2a inhibition also enhances urinary excretions of Na+, Cl-, and Ca2+, which is recapitulated in animal models with reduced kidney function. The effect of Npt2a inhibition by BAY-767 on vascular calcification has been studied, with positive results showing that oral treatment with BAY-767 (10 mg kg-1) attenuated the increases in plasma Pi and Ca2+ content in the aorta under the setting of vascular calcification induced by a pan-FGF receptor inhibitor. Together, Npt2a inhibition offers a promising therapeutic approach for treating hyperphosphatemia and reducing cardiovascular complications in CKD. SUMMARY Npt2a inhibition significantly increases urinary Pi excretion and lowers plasma Pi and PTH levels; moreover, it exerts pleiotropic "off-target" effects, providing a novel treatment for hyperphosphatemia and exhibiting beneficial potential for cardiovascular complications in CKD.
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10
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Hsu SN, Stephen LA, Dillon S, Milne E, Javaheri B, Pitsillides AA, Novak A, Millán JL, MacRae VE, Staines KA, Farquharson C. Increased PHOSPHO1 expression mediates cortical bone mineral density in renal osteodystrophy. J Endocrinol 2022; 254:153-167. [PMID: 35900032 PMCID: PMC9422252 DOI: 10.1530/joe-22-0097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Accepted: 07/25/2022] [Indexed: 11/08/2022]
Abstract
Patients with advanced chronic kidney disease (CKD) often present with skeletal abnormalities, a condition known as renal osteodystrophy (ROD). While tissue non-specific alkaline phosphatase (TNAP) and PHOSPHO1 are critical for bone mineralization, their role in the etiology of ROD is unclear. To address this, ROD was induced in both WT and Phospho1 knockout (P1KO) mice through dietary adenine supplementation. The mice presented with hyperphosphatemia, hyperparathyroidism, and elevated levels of FGF23 and bone turnover markers. In particular, we noted that in CKD mice, bone mineral density (BMD) was increased in cortical bone (P < 0.05) but decreased in trabecular bone (P < 0.05). These changes were accompanied by decreased TNAP (P < 0.01) and increased PHOSPHO1 (P < 0.001) expression in WT CKD bones. In P1KO CKD mice, the cortical BMD phenotype was rescued, suggesting that the increased cortical BMD of CKD mice was driven by increased PHOSPHO1 expression. Other structural parameters were also improved in P1KO CKD mice. We further investigated the driver of the mineralization defects, by studying the effects of FGF23, PTH, and phosphate administration on PHOSPHO1 and TNAP expression by primary murine osteoblasts. We found both PHOSPHO1 and TNAP expressions to be downregulated in response to phosphate and PTH. The in vitro data suggest that the TNAP reduction in CKD-MBD is driven by the hyperphosphatemia and/or hyperparathyroidism noted in these mice, while the higher PHOSPHO1 expression may be a compensatory mechanism. Increased PHOSPHO1 expression in ROD may contribute to the disordered skeletal mineralization characteristic of this progressive disorder.
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Affiliation(s)
- Shun-Neng Hsu
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian, UK
- Division of Nephrology, Department of Medicine, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan
| | - Louise A Stephen
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian, UK
| | - Scott Dillon
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian, UK
| | - Elspeth Milne
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian, UK
| | - Behzad Javaheri
- Comparative Biomedical Sciences, The Royal Veterinary College, London, UK
| | | | - Amanda Novak
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian, UK
| | - Jose Luis Millán
- Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California, USA
| | - Vicky E MacRae
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian, UK
| | - Katherine A Staines
- Centre for Stress and Age-Related Disease, University of Brighton, Brighton, UK
| | - Colin Farquharson
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian, UK
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11
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Collins MT, Marcucci G, Anders HJ, Beltrami G, Cauley JA, Ebeling PR, Kumar R, Linglart A, Sangiorgi L, Towler DA, Weston R, Whyte MP, Brandi ML, Clarke B, Thakker RV. Skeletal and extraskeletal disorders of biomineralization. Nat Rev Endocrinol 2022; 18:473-489. [PMID: 35578027 DOI: 10.1038/s41574-022-00682-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 04/13/2022] [Indexed: 12/15/2022]
Abstract
The physiological process of biomineralization is complex and deviation from it leads to a variety of diseases. Progress in the past 10 years has enhanced understanding of the genetic, molecular and cellular pathophysiology underlying these disorders; sometimes, this knowledge has both facilitated restoration of health and clarified the very nature of biomineralization as it occurs in humans. In this Review, we consider the principal regulators of mineralization and crystallization, and how dysregulation of these processes can lead to human disease. The knowledge acquired to date and gaps still to be filled are highlighted. The disorders of mineralization discussed comprise a broad spectrum of conditions that encompass bone disorders associated with alterations of mineral quantity and quality, as well as disorders of extraskeletal mineralization (hyperphosphataemic familial tumoural calcinosis). Included are disorders of alkaline phosphatase (hypophosphatasia) and phosphate homeostasis (X-linked hypophosphataemic rickets, fluorosis, rickets and osteomalacia). Furthermore, crystallopathies are covered as well as arterial and renal calcification. This Review discusses the current knowledge of biomineralization derived from basic and clinical research and points to future studies that will lead to new therapeutic approaches for biomineralization disorders.
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Affiliation(s)
- Michael T Collins
- Skeletal Disorders and Mineral Homeostasis Section, National Institute of Dental and Craniofacial Research, NIH, Bethesda, MD, USA.
| | - Gemma Marcucci
- Bone Metabolic Diseases Unit, Department of Biomedical, Experimental and Clinical Sciences, University of Florence, Florence, Italy
| | - Hans-Joachim Anders
- Department of Medicine IV, Hospital of the University of Munich, Ludwig-Maximilians University, Munich, Germany
| | - Giovanni Beltrami
- Department Paediatric Orthopedic Oncology, Careggi and Meyer Children Hospital, Florence, Italy
| | - Jane A Cauley
- Department of Epidemiology, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA, USA
| | - Peter R Ebeling
- Department of Medicine, School of Clinical Sciences, Monash University, Melbourne, Australia
| | - Rajiv Kumar
- Departments of Medicine, Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN, USA
| | - Agnès Linglart
- APHP, Endocrinologie et diabète de l'enfant, Paris, France
| | - Luca Sangiorgi
- Medical Genetics and Skeletal Rare Diseases, IRCCS Istituto Ortopedico Rizzoli, Bologna, Italy
| | - Dwight A Towler
- University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Ria Weston
- Cardiovascular Research Group, Manchester Metropolitan University, Manchester, UK
| | - Michael P Whyte
- Center for Metabolic Bone Disease and Molecular Research, Shriners Hospitals for Children-St Louis, St Louis, MO, USA
- Division of Bone and Mineral Diseases, Department of Internal Medicine, Washington University School of Medicine, St Louis, MO, USA
| | | | - Bart Clarke
- Mayo Clinic Division of Endocrinology, Diabetes, Metabolism, and Nutrition, Rochester, MN, USA
| | - Rajesh V Thakker
- Academic Endocrine Unit, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
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12
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Abstract
Phosphate homeostasis is dependent on the interaction and coordination of four main organ systems: thyroid/parathyroids, gastrointestinal tract, bone and kidneys, and three key hormonal regulators, 1,25-hydroxyvitamin D3, parathyroid hormone and FGF23 with its co- factor klotho. Phosphorus is a critical nutritional element for normal cellular function, but in excess can be toxic to tissues, particularly the vasculature. As phosphate, it also has an important interaction and inter-dependence with calcium and calcium homeostasis sharing some of the same controlling hormones, although this is not covered in our article. We have chosen to provide a current overview of phosphate homeostasis only, focusing on the role of two major organ systems, the gastrointestinal tract and kidneys, and their contribution to the control of phosphate balance. We describe in some detail the mechanisms of intestinal and renal phosphate transport, and compare and contrast their regulation. We also consider a significant example of phosphate imbalance, with phosphate retention, which is chronic kidney disease; why consequent hyperphosphatemia is important, and some of the newer means of managing it.
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Affiliation(s)
- Joanne Marks
- Department of Neuroscience, Physiology & Pharmacology, University College London, London, United Kingdom
| | - Robert J Unwin
- Department of Neuroscience, Physiology & Pharmacology, University College London, London, United Kingdom; Department of Renal Medicine, University College London, London, United Kingdom.
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13
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Abstract
PURPOSE OF REVIEW Progressive forms of chronic kidney disease (CKD) exhibit kidney inflammation and fibrosis that drive continued nephron loss; however, factors responsible for the development of these common pathologic features remain poorly defined. Recent investigations suggest pathways involved in maintaining urinary phosphate excretion in CKD may be contributing to kidney function decline. This review provides an update on recent evidence linking altered phosphate homeostasis to CKD progression. RECENT FINDINGS High dietary phosphate intake and increased serum concentrations of fibroblast growth factor 23 (FGF23) both increase urinary phosphate excretion and are associated with increased risk of kidney function decline. Recent investigations have discovered high concentrations of tubular phosphate promote phosphate-based nanocrystal formation that drives tubular injury, cyst formation, and fibrosis. SUMMARY Studies presented in this review highlight important scientific discoveries that have molded our current understanding of the contribution of altered phosphate homeostasis to CKD progression. The collective observations from these investigations implicate phosphaturia, and the resulting formation of phosphate-based crystals in tubular fluid, as unique risk factors for kidney function decline. Developing a better understanding of the relationship between tubular phosphate handling and kidney pathology could result in innovative strategies for improving kidney outcomes in patients with CKD.
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Affiliation(s)
- Kyle P Jansson
- The Jared Grantham Kidney Institute
- Department of Internal Medicine, Division of Nephrology & Hypertension, University of Kansas Medical Center, Kansas City, Kansas 66160, USA
| | - Alan S L Yu
- The Jared Grantham Kidney Institute
- Department of Internal Medicine, Division of Nephrology & Hypertension, University of Kansas Medical Center, Kansas City, Kansas 66160, USA
| | - Jason R Stubbs
- The Jared Grantham Kidney Institute
- Department of Internal Medicine, Division of Nephrology & Hypertension, University of Kansas Medical Center, Kansas City, Kansas 66160, USA
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14
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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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15
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Gu J, Shi J, Chen X, Mao J, You H, Chen J. High sodium reduced the expression of PTH1R and Klotho by inhibiting 1,25(OH) 2D 3 synthesis in cultured proximal tubule epithelial cells. ANNALS OF TRANSLATIONAL MEDICINE 2022; 10:506. [PMID: 35928745 PMCID: PMC9347055 DOI: 10.21037/atm-21-5910] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Accepted: 03/10/2022] [Indexed: 11/06/2022]
Abstract
Background The proximal tubule is the sensing site of sodium and phosphate and the main place for the synthesis and metabolism of 1,25(OH)2D3. We aimed to investigate the effects of high sodium on the synthesis and function of active vitamin D and local phosphate regulation in proximal tubular epithelial cells. Methods Human proximal tubule epithelial (HK-2) cells were treated with different concentrations of sodium/phosphate. The expression of 1α-OHase and 24-OHase was determined. Liquid chromatography/mass spectrometry (LC/MS) and enzyme-linked immunosorbent assay (ELISA) were used to detect the levels of 1,25(OH)2D3. RNA sequencing and bioinformatics analysis was used to probe into the possible pathways. Chromatin samples were immunoprecipitated with antibodies against parathyroid receptor 1 (PTH1R) and Klotho. Results We found that high sodium decreased the expression of 1,25(OH)2D3 by reducing 1α-OHase and 24-OHase, reduced the expression of PTH1R and Klotho, and increased the intracellular calcium concentration. These effects were reversed by sodium phosphate transporter inhibitor, sodium hydrogen transporter inhibitor, and a chelator of the extracellular calcium, whereas enhanced by ouabain. Vitamin D receptor (VDR) agonists significantly increased the recruitment of VDR to the vitamin D response element (VDRE) of PTH1R and Klotho promoter, thus increasing the expression of PTH1R and Klotho. Conclusions High sodium can decrease the synthesis of active vitamin D in the proximal tubules, affect the gene regulation of 1,25(OH)2D3/VDR, and significantly reduce the expression of PTH1R and Klotho. It revealed the influence of a high-sodium diet on mineral metabolism and the core role of vitamin D in kidney mineral metabolism.
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Affiliation(s)
- Jie Gu
- Division of Nephrology, Huashan Hospital, Fudan University, Shanghai, China
- National Clinical Research Center for Aging and Medicine, Huashan Hospital, Fudan University, Shanghai, China
| | - Jialin Shi
- Division of Nephrology, Huashan Hospital, Fudan University, Shanghai, China
- National Clinical Research Center for Aging and Medicine, Huashan Hospital, Fudan University, Shanghai, China
| | - Xujiao Chen
- Division of Nephrology, Huashan Hospital, Fudan University, Shanghai, China
- National Clinical Research Center for Aging and Medicine, Huashan Hospital, Fudan University, Shanghai, China
| | - Jianping Mao
- Division of Nephrology, Huashan Hospital, Fudan University, Shanghai, China
- National Clinical Research Center for Aging and Medicine, Huashan Hospital, Fudan University, Shanghai, China
| | - Huaizhou You
- Division of Nephrology, Huashan Hospital, Fudan University, Shanghai, China
- National Clinical Research Center for Aging and Medicine, Huashan Hospital, Fudan University, Shanghai, China
| | - Jing Chen
- Division of Nephrology, Huashan Hospital, Fudan University, Shanghai, China
- National Clinical Research Center for Aging and Medicine, Huashan Hospital, Fudan University, Shanghai, China
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16
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Npt2a as a target for treating hyperphosphatemia. Biochem Soc Trans 2022; 50:439-446. [PMID: 34994388 PMCID: PMC9022968 DOI: 10.1042/bst20211005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2021] [Revised: 12/08/2021] [Accepted: 12/13/2021] [Indexed: 12/04/2022]
Abstract
Hyperphosphatemia results from an imbalance in phosphate (Pi) homeostasis. In patients with and without reduced kidney function, hyperphosphatemia is associated with cardiovascular complications. The current mainstays in the management of hyperphosphatemia are oral Pi binder and dietary Pi restriction. Although these options are employed in patients with chronic kidney disease (CKD), they seem inadequate to correct elevated plasma Pi levels. In addition, a paradoxical increase in expression of intestinal Pi transporter and uptake may occur. Recently, studies in rodents targeting the renal Na+/Pi cotransporter 2a (Npt2a), responsible for ∼70% of Pi reabsorption, have been proposed as a potential treatment option. Two compounds (PF-06869206 and BAY-767) have been developed which are selective for Npt2a. These Npt2a inhibitors significantly increased urinary Pi excretion consequently lowering plasma Pi and PTH levels. Additionally, increases in urinary excretions of Na+, Cl− and Ca2+ have been observed. Some of these results are also seen in models of reduced kidney function. Responses of FGF23, a phosphaturic hormone that has been linked to the development of left ventricular hypertrophy in CKD, are ambiguous. In this review, we discuss the recent advances on the role of Npt2a inhibition on Pi homeostasis as well as other pleiotropic effects observed with Npt2a inhibition.
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17
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Czaya B, Heitman K, Campos I, Yanucil C, Kentrup D, Westbrook D, Gutierrez O, Babitt JL, Jung G, Salusky IB, Hanudel M, Faul C. Hyperphosphatemia increases inflammation to exacerbate anemia and skeletal muscle wasting independently of FGF23-FGFR4 signaling. eLife 2022; 11:74782. [PMID: 35302487 PMCID: PMC8963881 DOI: 10.7554/elife.74782] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2021] [Accepted: 03/17/2022] [Indexed: 12/01/2022] Open
Abstract
Elevations in plasma phosphate concentrations (hyperphosphatemia) occur in chronic kidney disease (CKD), in certain genetic disorders, and following the intake of a phosphate-rich diet. Whether hyperphosphatemia and/or associated changes in metabolic regulators, including elevations of fibroblast growth factor 23 (FGF23) directly contribute to specific complications of CKD is uncertain. Here, we report that similar to patients with CKD, mice with adenine-induced CKD develop inflammation, anemia, and skeletal muscle wasting. These complications are also observed in mice fed high phosphate diet even without CKD. Ablation of pathologic FGF23-FGFR4 signaling did not protect mice on an increased phosphate diet or mice with adenine-induced CKD from these sequelae. However, low phosphate diet ameliorated anemia and skeletal muscle wasting in a genetic mouse model of CKD. Our mechanistic in vitro studies indicate that phosphate elevations induce inflammatory signaling and increase hepcidin expression in hepatocytes, a potential causative link between hyperphosphatemia, anemia, and skeletal muscle dysfunction. Our study suggests that high phosphate intake, as caused by the consumption of processed food, may have harmful effects irrespective of pre-existing kidney injury, supporting not only the clinical utility of treating hyperphosphatemia in CKD patients but also arguing for limiting phosphate intake in healthy individuals.
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Affiliation(s)
- Brian Czaya
- Division of Nephrology and Hypertension, Department of Medicine, The University of Alabama at BirminghamBirminghamUnited States,Department of Medicine, David Geffen School of Medicine at UCLALos AngelesUnited States
| | - Kylie Heitman
- Division of Nephrology and Hypertension, Department of Medicine, The University of Alabama at BirminghamBirminghamUnited States
| | - Isaac Campos
- Division of Nephrology and Hypertension, Department of Medicine, The University of Alabama at BirminghamBirminghamUnited States
| | - Christopher Yanucil
- Division of Nephrology and Hypertension, Department of Medicine, The University of Alabama at BirminghamBirminghamUnited States
| | - Dominik Kentrup
- Division of Nephrology and Hypertension, Department of Medicine, The University of Alabama at BirminghamBirminghamUnited States
| | - David Westbrook
- Division of Nephrology and Hypertension, Department of Medicine, The University of Alabama at BirminghamBirminghamUnited States
| | - Orlando Gutierrez
- Division of Nephrology and Hypertension, Department of Medicine, The University of Alabama at BirminghamBirminghamUnited States
| | - Jodie L Babitt
- Division of Nephrology, Program in Membrane Biology, Massachusetts General Hospital, Harvard Medical SchoolBostonUnited States
| | - Grace Jung
- Department of Medicine, David Geffen School of Medicine at UCLALos AngelesUnited States
| | - Isidro B Salusky
- Department of Pediatrics, David Geffen School of Medicine at UCLALos AngelesUnited States
| | - Mark Hanudel
- Department of Pediatrics, David Geffen School of Medicine at UCLALos AngelesUnited States
| | - Christian Faul
- Division of Nephrology and Hypertension, Department of Medicine, The University of Alabama at BirminghamBirminghamUnited States
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18
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Lenherr-Taube N, Young EJ, Furman M, Elia Y, Assor E, Chitayat D, Uster T, Kirwin S, Robbins K, Vinette KMB, Daneman A, Marshall CR, Collins C, Thummel K, Sochett E, Levine MA. Mild Idiopathic Infantile Hypercalcemia-Part 1: Biochemical and Genetic Findings. J Clin Endocrinol Metab 2021; 106:2915-2937. [PMID: 34125233 PMCID: PMC8475208 DOI: 10.1210/clinem/dgab431] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Indexed: 11/19/2022]
Abstract
CONTEXT Idiopathic infantile hypercalcemia (IIH), an uncommon disorder characterized by elevated serum concentrations of 1,25 dihydroxyvitamin D (1,25(OH)2D) and low parathyroid hormone (PTH) levels, may present with mild to severe hypercalcemia during the first months of life. Biallelic variants in the CYP24A1 or SLC34A1 genes are associated with severe IIH. Little is known about milder forms. OBJECTIVE This work aims to characterize the genetic associations and biochemical profile of mild IIH. METHODS This is a cross-sectional study including children between age 6 months and 17 years with IIH who were followed in the Calcium Clinic at the Hospital for Sick Children (SickKids), Toronto, Canada. Twenty children with mild IIH on calcium-restricted diets were evaluated. We performed a dietary assessment and analyzed biochemical measures including vitamin D metabolites and performed a stepwise molecular genetic analysis. Complementary biochemical assessments and renal ultrasounds were offered to first-degree family members of positive probands. RESULTS The median age was 16 months. Median serum levels of calcium (2.69 mmol/L), urinary calcium:creatinine ratio (0.72 mmol/mmol), and 1,25(OH)2D (209 pmol/L) were elevated, whereas intact PTH was low normal (22.5 ng/L). Mean 1,25(OH)2D/PTH and 1,25(OH)2D/25(OH)D ratios were increased by comparison to healthy controls. Eleven individuals (55%) had renal calcification. Genetic variants were common (65%), with the majority being heterozygous variants in SLC34A1 and SLC34A3, while a minority showed variants of CYP24A1 and other genes related to hypercalciuria. CONCLUSION The milder form of IIH has a distinctive vitamin D metabolite profile and is primarily associated with heterozygous SLC34A1 and SLC34A3 variants.
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Affiliation(s)
- Nina Lenherr-Taube
- Department of Pediatrics, Division of Endocrinology, The Hospital for Sick Children, University of Toronto, M5G 1X8 Toronto, Ontario, Canada
| | - Edwin J Young
- Genome Diagnostics, Department of Paediatric Medicine, The Hospital for Sick Children, M5G 1X8 Toronto, Ontario, Canada
| | - Michelle Furman
- Department of Pediatrics, Division of Endocrinology, The Hospital for Sick Children, University of Toronto, M5G 1X8 Toronto, Ontario, Canada
| | - Yesmino Elia
- Department of Pediatrics, Division of Endocrinology, The Hospital for Sick Children, University of Toronto, M5G 1X8 Toronto, Ontario, Canada
| | - Esther Assor
- Department of Pediatrics, Division of Endocrinology, The Hospital for Sick Children, University of Toronto, M5G 1X8 Toronto, Ontario, Canada
| | - David Chitayat
- Department of Obstetrics and Gynecology, The Prenatal Diagnosis and Medical Genetics Program, Mount Sinai Hospital, University of Toronto, M5G 1X8 Toronto, Ontario, Canada
- Department of Pediatrics, Division of Clinical Genetics and Metabolism, The Hospital for Sick Children, University of Toronto, M5G 1X8 Toronto, Ontario, Canada
| | - Tami Uster
- Department of Obstetrics and Gynecology, The Prenatal Diagnosis and Medical Genetics Program, Mount Sinai Hospital, University of Toronto, M5G 1X8 Toronto, Ontario, Canada
| | - Susan Kirwin
- Nemours Molecular Diagnostics Laboratory, Nemours Children’s Health System, Wilmington, Delaware 19802, USA
| | - Katherine Robbins
- Nemours Molecular Diagnostics Laboratory, Nemours Children’s Health System, Wilmington, Delaware 19802, USA
| | - Kathleen M B Vinette
- Nemours Molecular Diagnostics Laboratory, Nemours Children’s Health System, Wilmington, Delaware 19802, USA
| | - Alan Daneman
- Department of Diagnostic Imaging, Division of General Radiology and Body Imaging, The Hospital for Sick Children, University of Toronto, M5G 1X8 Toronto, Ontario, Canada
| | - Christian R Marshall
- Genome Diagnostics, Department of Paediatric Medicine, The Hospital for Sick Children, M5G 1X8 Toronto, Ontario, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, M5S 1A8 Toronto, Ontario, Canada
| | - Carol Collins
- Department of Pharmaceutics, University of Washington, Seattle, Washington 98195, USA
| | - Kenneth Thummel
- Department of Pharmaceutics, University of Washington, Seattle, Washington 98195, USA
| | - Etienne Sochett
- Department of Pediatrics, Division of Endocrinology, The Hospital for Sick Children, University of Toronto, M5G 1X8 Toronto, Ontario, Canada
| | - Michael A Levine
- Division of Endocrinology and Diabetes and Center for Bone Health, Children’s Hospital of Philadelphia and Department of Pediatrics, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania 19104, USA
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19
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Drueke TB. Increase in phosphaturia by inhibition of renal sodium-dependent phosphate cotransporter NPT2a. Kidney Int 2020; 99:533-536. [PMID: 33069763 DOI: 10.1016/j.kint.2020.09.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Accepted: 09/24/2020] [Indexed: 10/23/2022]
Affiliation(s)
- Tilman B Drueke
- Inserm Unit 1018, Team 5, CESP, Hôpital Paul Brousse, Paris-Sud University and Versailles Saint-Quentin-en-Yvelines University (Paris-Ile-de-France-Ouest University, UVSQ), Villejuif, France.
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