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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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2
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Gombedza FC, Shin S, Sadiua J, Stackhouse GB, Bandyopadhyay BC. The Rise in Tubular pH during Hypercalciuria Exacerbates Calcium Stone Formation. Int J Mol Sci 2024; 25:4787. [PMID: 38732005 PMCID: PMC11084476 DOI: 10.3390/ijms25094787] [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: 03/15/2024] [Revised: 04/24/2024] [Accepted: 04/25/2024] [Indexed: 05/13/2024] Open
Abstract
In calcium nephrolithiasis (CaNL), most calcium kidney stones are identified as calcium oxalate (CaOx) with variable amounts of calcium phosphate (CaP), where CaP is found as the core component. The nucleation of CaP could be the first step of CaP+CaOx (mixed) stone formation. High urinary supersaturation of CaP due to hypercalciuria and an elevated urine pH have been described as the two main factors in the nucleation of CaP crystals. Our previous in vivo findings (in mice) show that transient receptor potential canonical type 3 (TRPC3)-mediated Ca2+ entry triggers a transepithelial Ca2+ flux to regulate proximal tubular (PT) luminal [Ca2+], and TRPC3-knockout (KO; -/-) mice exhibited moderate hypercalciuria and microcrystal formation at the loop of Henle (LOH). Therefore, we utilized TRPC3 KO mice and exposed them to both hypercalciuric [2% calcium gluconate (CaG) treatment] and alkalineuric conditions [0.08% acetazolamide (ACZ) treatment] to generate a CaNL phenotype. Our results revealed a significant CaP and mixed crystal formation in those treated KO mice (KOT) compared to their WT counterparts (WTT). Importantly, prolonged exposure to CaG and ACZ resulted in a further increase in crystal size for both treated groups (WTT and KOT), but the KOT mice crystal sizes were markedly larger. Moreover, kidney tissue sections of the KOT mice displayed a greater CaP and mixed microcrystal formation than the kidney sections of the WTT group, specifically in the outer and inner medullary and calyceal region; thus, a higher degree of calcifications and mixed calcium lithiasis in the kidneys of the KOT group was displayed. In our effort to find the Ca2+ signaling pathophysiology of PT cells, we found that PT cells from both treated groups (WTT and KOT) elicited a larger Ca2+ entry compared to the WT counterparts because of significant inhibition by the store-operated Ca2+ entry (SOCE) inhibitor, Pyr6. In the presence of both SOCE (Pyr6) and ROCE (receptor-operated Ca2+ entry) inhibitors (Pyr10), Ca2+ entry by WTT cells was moderately inhibited, suggesting that the Ca2+ and pH levels exerted sensitivity changes in response to ROCE and SOCE. An assessment of the gene expression profiles in the PT cells of WTT and KOT mice revealed a safeguarding effect of TRPC3 against detrimental processes (calcification, fibrosis, inflammation, and apoptosis) in the presence of higher pH and hypercalciuric conditions in mice. Together, these findings show that compromise in both the ROCE and SOCE mechanisms in the absence of TRPC3 under hypercalciuric plus higher tubular pH conditions results in higher CaP and mixed crystal formation and that TRPC3 is protective against those adverse effects.
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Affiliation(s)
- Farai C. Gombedza
- Calcium Signaling Laboratory, Research Service, Veterans Affairs Medical Center, 50 Irving Street, NW, Washington, DC 20422, USA; (F.C.G.); (S.S.); (J.S.)
| | - Samuel Shin
- Calcium Signaling Laboratory, Research Service, Veterans Affairs Medical Center, 50 Irving Street, NW, Washington, DC 20422, USA; (F.C.G.); (S.S.); (J.S.)
- Department of Biomedical Engineering, The Catholic University of America, 620 Michigan Avenue NE, Washington, DC 20064, USA
| | - Jaclyn Sadiua
- Calcium Signaling Laboratory, Research Service, Veterans Affairs Medical Center, 50 Irving Street, NW, Washington, DC 20422, USA; (F.C.G.); (S.S.); (J.S.)
| | - George B. Stackhouse
- Urology Service, Veterans Affairs Medical Center, 50 Irving Street, NW, Washington, DC 20422, USA;
| | - Bidhan C. Bandyopadhyay
- Calcium Signaling Laboratory, Research Service, Veterans Affairs Medical Center, 50 Irving Street, NW, Washington, DC 20422, USA; (F.C.G.); (S.S.); (J.S.)
- Department of Biomedical Engineering, The Catholic University of America, 620 Michigan Avenue NE, Washington, DC 20064, USA
- Division of Renal Diseases & Hypertension, Department of Medicine, The George Washington University, Washington, DC 20037, USA
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3
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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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Shin S, Boadi EA, Bandyopadhyay BC. Ablation of TRPC3 compromises bicarbonate and phosphate transporter activity in mice proximal tubular cells. Clin Exp Pharmacol Physiol 2023; 50:247-255. [PMID: 36433745 PMCID: PMC10258833 DOI: 10.1111/1440-1681.13741] [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: 05/11/2022] [Revised: 11/19/2022] [Accepted: 11/21/2022] [Indexed: 11/28/2022]
Abstract
Proximal tubular (PT) cells reabsorb most calcium (Ca2+ ), phosphate (PO4 3- ), bicarbonate (HCO3 - ), and oxalate (C2 O4 2- ) ions. We have shown that mice lacking Transient Receptor Potential Canonical 3 (TRPC3-/- ) channel are moderately hypercalciuric with presentation of luminal calcium phosphate (CaP) crystals at the loop of Henle (LOH). However, other predisposing factors for such crystal deposition are unknown. Thus, we examined the distinctions in functional status of HCO3 - , PO4 3- , and C2 O4 2- transporters in PT cells of wild type (WT) and TRPC3-/- mice by whole-cell patch clamp techniques to assess their contribution in the development of LOH CaP crystals. Here we show the development of concentration dependent HCO3 - -induced currents in all PT cells, which was confirmed by using specific HCO3 - channel inhibitor, S0859. Interestingly, such activities were diminished in PT cells from TRPC3-/- mice, suggesting reduced HCO3 - transport in absence of TRPC3. While PO4 3- -induced currents were also concentration dependent in all PT cells (confirmed by PO4 3- channel inhibitor, PF-06869206), those activities were reduced in absence of TRPC3, suggesting lower PO4 3- reabsorption that can leave excess luminal PO4 3- . Next, we applied thiosulfate (O3 S2 2 - ) as a competitive inhibitor of the SLC26a6 transporter upon C2 O4 2- current activation and observed a reduced C2 O4 2- -induced conductance which was greater in TRPC3-/- PT cells. Together, these results suggest that the reduced activities of HCO3 - , PO4 3- , and C2 O4 2- transporters in moderately hypercalciuric (TRPC3-/- ) PT cells can create a predisposing condition for CaP and CaP tubular crystallization, enabling CaP crystal formation in LOH of TRPC3-/- mice.
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Affiliation(s)
- Samuel Shin
- Calcium Signaling Laboratory, Research Service, Veterans Affairs Medical Center, Washington, Columbia, USA
| | - Eugenia Awuah Boadi
- Calcium Signaling Laboratory, Research Service, Veterans Affairs Medical Center, Washington, Columbia, USA
| | - Bidhan C. Bandyopadhyay
- Calcium Signaling Laboratory, Research Service, Veterans Affairs Medical Center, Washington, Columbia, USA
- Division of Renal Diseases & Hypertension, Department of Medicine, The George Washington University, Washington, Columbia, USA
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Chande S, Caballero D, Ho BB, Fetene J, Serna J, Pesta D, Nasiri A, Jurczak M, Chavkin NW, Hernando N, Giachelli CM, Wagner CA, Zeiss C, Shulman GI, Bergwitz C. Slc20a1/Pit1 and Slc20a2/Pit2 are essential for normal skeletal myofiber function and survival. Sci Rep 2020; 10:3069. [PMID: 32080237 PMCID: PMC7033257 DOI: 10.1038/s41598-020-59430-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2019] [Accepted: 01/29/2020] [Indexed: 01/25/2023] Open
Abstract
Low blood phosphate (Pi) reduces muscle function in hypophosphatemic disorders. Which Pi transporters are required and whether hormonal changes due to hypophosphatemia contribute to muscle function is unknown. To address these questions we generated a series of conditional knockout mice lacking one or both house-keeping Pi transporters Pit1 and Pit2 in skeletal muscle (sm), using the postnatally expressed human skeletal actin-cre. Simultaneous conditional deletion of both transporters caused skeletal muscle atrophy, resulting in death by postnatal day P13. smPit1-/-, smPit2-/- and three allele mutants are fertile and have normal body weights, suggesting a high degree of redundance for the two transporters in skeletal muscle. However, these mice show a gene-dose dependent reduction in running activity also seen in another hypophosphatemic model (Hyp mice). In contrast to Hyp mice, grip strength is preserved. Further evaluation of the mechanism shows reduced ERK1/2 activation and stimulation of AMP kinase in skeletal muscle from smPit1-/-; smPit2-/- mice consistent with energy-stress. Similarly, C2C12 myoblasts show a reduced oxygen consumption rate mediated by Pi transport-dependent and ERK1/2-dependent metabolic Pi sensing pathways. In conclusion, we here show that Pit1 and Pit2 are essential for normal myofiber function and survival, insights which may improve management of hypophosphatemic myopathy.
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Affiliation(s)
- Sampada Chande
- Department of Internal Medicine, Section Endocrinology, Yale University School of Medicine, New Haven, CT, USA
| | - Daniel Caballero
- Department of Internal Medicine, Section Endocrinology, Yale University School of Medicine, New Haven, CT, USA
| | - Bryan B Ho
- Department of Internal Medicine, Section Endocrinology, Yale University School of Medicine, New Haven, CT, USA
| | - Jonathan Fetene
- Department of Internal Medicine, Section Endocrinology, Yale University School of Medicine, New Haven, CT, USA
| | - Juan Serna
- Department of Internal Medicine, Section Endocrinology, Yale University School of Medicine, New Haven, CT, USA
| | - Dominik Pesta
- Department of Cellular&Molecular Physiology, Yale University School of Medicine, New Haven, CT, USA
- German Diabetes Center, Düsseldorf, Germany, University of Washington, Box 355061, Foege Hall Seattle, WA, 98195, USA
| | - Ali Nasiri
- Department of Cellular&Molecular Physiology, Yale University School of Medicine, New Haven, CT, USA
| | - Michael Jurczak
- Department of Internal Medicine, Section Endocrinology, Yale University School of Medicine, New Haven, CT, USA
- Department of Medicine, Division of Endocrinology, University of Pittsburgh, University of Washington, Box 355061, Foege Hall Seattle, WA, 98195, USA
| | - Nicholas W Chavkin
- Department of Bioengineering, University of Washington, Box 355061, Foege Hall Seattle, WA, 98195, USA
| | - Nati Hernando
- Institute of Physiology, University of Zürich, Switzerland and National Center of Competence in Research NCCR Kidney.CH, Zürich, Switzerland
| | - Cecilia M Giachelli
- Department of Bioengineering, University of Washington, Box 355061, Foege Hall Seattle, WA, 98195, USA
| | - Carsten A Wagner
- Institute of Physiology, University of Zürich, Switzerland and National Center of Competence in Research NCCR Kidney.CH, Zürich, Switzerland
| | - Caroline Zeiss
- Comparative Medicine, Yale University School of Medicine, New Haven, CT, USA
| | - Gerald I Shulman
- Department of Internal Medicine, Section Endocrinology, Yale University School of Medicine, New Haven, CT, USA
- Department of Cellular&Molecular Physiology, Yale University School of Medicine, New Haven, CT, USA
| | - Clemens Bergwitz
- Department of Internal Medicine, Section Endocrinology, Yale University School of Medicine, New Haven, CT, USA.
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Chande S, Ho B, Fetene J, Bergwitz C. Transgenic mouse model for conditional expression of influenza hemagglutinin-tagged human SLC20A1/PIT1. PLoS One 2019; 14:e0223052. [PMID: 31613887 PMCID: PMC6793878 DOI: 10.1371/journal.pone.0223052] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2019] [Accepted: 09/12/2019] [Indexed: 11/19/2022] Open
Abstract
To further investigate the role of the phosphate (Pi) transporter PIT1 in Pi homeostasis and tissue mineralization, we developed a transgenic mouse expressing the C-terminal influenza hemagglutinin (HA) epitope-tagged human PIT1 transporter under control of the cytomegalovirus/chicken beta actin/rabbit beta-globin gene (CAG) promotor and a loxP-stop-loxP (LSL) cassette permitting conditional activation of transgene expression (LSL-HA-hPITtg/+). For an initial characterization of this conditional mouse model, germline excision of the LSL cassette was performed to induce expression of the transgene in all mouse tissues (HA-hPIT1tg/+). Recombination was confirmed using genomic DNA obtained from blood samples of these mice. Furthermore, expression of HA-hPIT1 was found to be at least 10-fold above endogenous mouse Pit1 in total RNA isolated from multiple tissues and from cultured primary calvaria osteoblasts (PCOB) estimated by semi-quantitative RT-PCR. Robust expression of the HA-hPIT1 protein was also observed upon immunoblot analysis in most tissues and permits HA-mediated immunoprecipitation of the transporter. Characterization of the phenotype of HA-hPIT1tg/+ mice at 80 days of age when fed a standard chow (0.7% Pi and 1% calcium) showed elevated plasma Pi, but normal plasma iPTH, iFGF23, serum calcium, BUN, 1,25-dihydroxy vitamin D levels and urine Pi, calcium and protein excretion when compared to WT littermates. Likewise, no change in bone mineral density was observed upon uCT analysis of the distal femur obtained from these mice. In conclusion, heterozygous overexpression of HA-hPIT1 is compatible with life and causes hyperphosphatemia while bone and mineral metabolism of these mice are otherwise normal.
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Affiliation(s)
- Sampada Chande
- Section of Endocrinology and Metabolism, Yale University School of Medicine, New Haven, CT, United States of America
| | - Bryan Ho
- Section of Endocrinology and Metabolism, Yale University School of Medicine, New Haven, CT, United States of America
| | - Jonathan Fetene
- Section of Endocrinology and Metabolism, Yale University School of Medicine, New Haven, CT, United States of America
| | - Clemens Bergwitz
- Section of Endocrinology and Metabolism, Yale University School of Medicine, New Haven, CT, United States of America
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Rose E, Lee D, Xiao E, Zhao W, Wee M, Cohen J, Bergwitz C. Endocrine regulation of MFS2 by branchless controls phosphate excretion and stone formation in Drosophila renal tubules. Sci Rep 2019; 9:8798. [PMID: 31217461 PMCID: PMC6584732 DOI: 10.1038/s41598-019-45269-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Accepted: 04/16/2019] [Indexed: 12/15/2022] Open
Abstract
How inorganic phosphate (Pi) homeostasis is regulated in Drosophila is currently unknown. We here identify MFS2 as a key Pi transporter in fly renal (Malpighian) tubules. Consistent with its role in Pi excretion, we found that dietary Pi induces MFS2 expression. This results in the formation of Malpighian calcium-Pi stones, while RNAi-mediated knockdown of MFS2 increases blood (hemolymph) Pi and decreases formation of Malpighian tubule stones in flies cultured on high Pi medium. Conversely, microinjection of adults with the phosphaturic human hormone fibroblast growth factor 23 (FGF23) induces tubule expression of MFS2 and decreases blood Pi. This action of FGF23 is blocked by genetic ablation of MFS2. Furthermore, genetic overexpression of the fly FGF branchless (bnl) in the tubules induces expression of MFS2 and increases Malpighian tubule stones suggesting that bnl is the endogenous phosphaturic hormone in adult flies. Finally, genetic ablation of MFS2 increased fly life span, suggesting that Malpighian tubule stones are a key element whereby high Pi diet reduces fly longevity previously reported by us. In conclusion, MFS2 mediates excretion of Pi in Drosophila, which is as in higher species under the hormonal control of FGF-signaling.
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Affiliation(s)
- Emily Rose
- Section Endocrinology, Yale School of Medicine, New Haven, CT, USA
| | - Daniela Lee
- Section Endocrinology, Yale School of Medicine, New Haven, CT, USA
| | - Emily Xiao
- Section Endocrinology, Yale School of Medicine, New Haven, CT, USA
| | - Wenzhen Zhao
- Section Endocrinology, Yale School of Medicine, New Haven, CT, USA
| | - Mark Wee
- Endocrine Unit, Massachusetts General Hospital, Boston, MA, USA
| | - Jonathan Cohen
- Endocrine Unit, Massachusetts General Hospital, Boston, MA, USA
| | - Clemens Bergwitz
- Section Endocrinology, Yale School of Medicine, New Haven, CT, USA.
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Beck-Nielsen SS, Mughal Z, Haffner D, Nilsson O, Levtchenko E, Ariceta G, de Lucas Collantes C, Schnabel D, Jandhyala R, Mäkitie O. FGF23 and its role in X-linked hypophosphatemia-related morbidity. Orphanet J Rare Dis 2019; 14:58. [PMID: 30808384 PMCID: PMC6390548 DOI: 10.1186/s13023-019-1014-8] [Citation(s) in RCA: 145] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Accepted: 01/30/2019] [Indexed: 12/29/2022] Open
Abstract
Background X-linked hypophosphatemia (XLH) is an inherited disease of phosphate metabolism in which inactivating mutations of the Phosphate Regulating Endopeptidase Homolog, X-Linked (PHEX) gene lead to local and systemic effects including impaired growth, rickets, osteomalacia, bone abnormalities, bone pain, spontaneous dental abscesses, hearing difficulties, enthesopathy, osteoarthritis, and muscular dysfunction. Patients with XLH present with elevated levels of fibroblast growth factor 23 (FGF23), which is thought to mediate many of the aforementioned manifestations of the disease. Elevated FGF23 has also been observed in many other diseases of hypophosphatemia, and a range of animal models have been developed to study these diseases, yet the role of FGF23 in the pathophysiology of XLH is incompletely understood. Methods The role of FGF23 in the pathophysiology of XLH is here reviewed by describing what is known about phenotypes associated with various PHEX mutations, animal models of XLH, and non-nutritional diseases of hypophosphatemia, and by presenting molecular pathways that have been proposed to contribute to manifestations of XLH. Results The pathophysiology of XLH is complex, involving a range of molecular pathways that variously contribute to different manifestations of the disease. Hypophosphatemia due to elevated FGF23 is the most obvious contributor, however localised fluctuations in tissue non-specific alkaline phosphatase (TNAP), pyrophosphate, calcitriol and direct effects of FGF23 have been observed to be associated with certain manifestations. Conclusions By describing what is known about these pathways, this review highlights key areas for future research that would contribute to the understanding and clinical treatment of non-nutritional diseases of hypophosphatemia, particularly XLH.
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Affiliation(s)
| | - Zulf Mughal
- Royal Manchester Children's Hospital, Manchester, UK
| | | | - Ola Nilsson
- Karolinska Institutet, Stockholm, Sweden and Örebro University, Örebro, Sweden
| | | | - Gema Ariceta
- Hospital Universitario Materno-Infantil Vall d'Hebron, Universitat Autonoma de Barcelona, Barcelona, Spain
| | | | - Dirk Schnabel
- University Children's Hospital of Berlin, Berlin, Germany
| | | | - Outi Mäkitie
- Children's Hospital, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
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9
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Bergwitz C, Miyamoto KI. Hereditary hypophosphatemic rickets with hypercalciuria: pathophysiology, clinical presentation, diagnosis and therapy. Pflugers Arch 2018; 471:149-163. [PMID: 30109410 DOI: 10.1007/s00424-018-2184-2] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Revised: 07/06/2018] [Accepted: 07/10/2018] [Indexed: 12/24/2022]
Abstract
Hereditary hypophosphatemic rickets with hypercalciuria (HHRH; OMIM: 241530) is a rare autosomal recessive disorder with an estimated prevalence of 1:250,000 that was originally described by Tieder et al. Individuals with HHRH carry compound-heterozygous or homozygous (comp/hom) loss-of-function mutations in the sodium-phosphate co-transporter NPT2c. These mutations result in the development of urinary phosphate (Pi) wasting and hypophosphatemic rickets, bowing, and short stature, as well as appropriately elevated 1,25(OH)2D levels, which sets this fibroblast growth factor 23 (FGF23)-independent disorder apart from the more common X-linked hypophosphatemia. The elevated 1,25(OH)2D levels in turn result in hypercalciuria due to enhanced intestinal calcium absorption and reduced parathyroid hormone (PTH)-dependent calcium-reabsorption in the distal renal tubules, leading to the development of kidney stones and/or nephrocalcinosis in approximately half of the individuals with HHRH. Even heterozygous NPT2c mutations are frequently associated with isolated hypercalciuria (IH), which increases the risk of kidney stones or nephrocalcinosis threefold in affected individuals compared with the general population. Bone disease is generally absent in individuals with IH, in contrast to those with HHRH. Treatment of HHRH and IH consists of monotherapy with oral Pi supplements, while active vitamin D analogs are contraindicated, mainly because the endogenous 1,25(OH)2D levels are already elevated but also to prevent further worsening of the hypercalciuria. Long-term studies to determine whether oral Pi supplementation alone is sufficient to prevent renal calcifications and bone loss, however, are lacking. It is also unknown how therapy should be monitored, whether secondary hyperparathyroidism can develop, and whether Pi requirements decrease with age, as observed in some FGF23-dependent hypophosphatemic disorders, or whether this can lead to osteoporosis.
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Affiliation(s)
- Clemens Bergwitz
- Section Endocrinology and Metabolism, Yale University School of Medicine, Anlyan Center, Office S117, Lab S110, 1 Gilbert Street, New Haven, CT 06519, USA.
| | - Ken-Ichi Miyamoto
- Department of Molecular Nutrition, Tokushima University Graduate School of Biomedical Sciences, Tokushima, Japan
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Caballero D, Li Y, Fetene J, Ponsetto J, Chen A, Zhu C, Braddock DT, Bergwitz C. Intraperitoneal pyrophosphate treatment reduces renal calcifications in Npt2a null mice. PLoS One 2017; 12:e0180098. [PMID: 28704395 PMCID: PMC5509111 DOI: 10.1371/journal.pone.0180098] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Accepted: 06/09/2017] [Indexed: 12/12/2022] Open
Abstract
Mutations in the proximal tubular sodium-dependent phosphate co-transporters NPT2a and NPT2c have been reported in patients with renal stone disease and nephrocalcinosis, however the relative contribution of genotype, dietary calcium and phosphate, and modifiers of mineralization such as pyrophosphate (PPi) to the formation of renal mineral deposits is unclear. In the present study, we used Npt2a-/- mice to model the renal calcifications observed in these disorders. We observed elevated urinary excretion of PPi in Npt2a-/- mice when compared to WT mice. Presence of two hypomorphic Extracellular nucleotide pyrophosphatase phosphodiesterase 1 (Enpp1asj/asj) alleles decreased urine PPi and worsened renal calcifications in Npt2a-/- mice. These studies suggest that PPi is a thus far unrecognized factor protecting Npt2a-/- mice from the development of renal mineral deposits. Consistent with this conclusion, we next showed that renal calcifications in these mice can be reduced by intraperitoneal administration of sodium pyrophosphate. If confirmed in humans, urine PPi could therefore be of interest for developing new strategies to prevent the nephrocalcinosis and nephrolithiasis seen in phosphaturic disorders.
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Affiliation(s)
- Daniel Caballero
- Department of Medicine, Section Endocrinology, Yale University School of Medicine, New Haven, CT, United States of America
| | - Yuwen Li
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, United States of America
- Department of Pediatrics, The First Affiliated Hospital, Nanjing Medical University, Nanjing, Jiangsu Province, China
| | - Jonathan Fetene
- Department of Medicine, Section Endocrinology, Yale University School of Medicine, New Haven, CT, United States of America
| | - Julian Ponsetto
- Department of Medicine, Section Endocrinology, Yale University School of Medicine, New Haven, CT, United States of America
| | - Alyssa Chen
- Department of Medicine, Section Endocrinology, Yale University School of Medicine, New Haven, CT, United States of America
| | - Chuanlong Zhu
- Gastroenterology Unit, Massachusetts General Hospital and Harvard Medical School, Boston, United States of America
- Department of Infectious Diseases, The First Affiliated Hospital, Nanjing Medical University, Nanjing, Jiangsu Province, China
| | - Demetrios T. Braddock
- Department of Pathology, Yale University School of Medicine, New Haven, CT, United States of America
| | - Clemens Bergwitz
- Department of Medicine, Section Endocrinology, Yale University School of Medicine, New Haven, CT, United States of America
- * E-mail:
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