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Poulsen SB, Murali SK, Thomas L, Assmus A, Rosenbæk LL, Nielsen R, Dimke H, Rieg T, Fenton RA. Genetic deletion of the kidney sodium/proton exchanger-3 (NHE3) does not alter calcium and phosphate balance due to compensatory responses. Kidney Int 2024:S0085-2538(24)00533-7. [PMID: 39089578 DOI: 10.1016/j.kint.2024.07.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 06/10/2024] [Accepted: 07/02/2024] [Indexed: 08/04/2024]
Abstract
The sodium/proton exchanger-3 (NHE3) plays a major role in acid-base and extracellular volume regulation and is also implicated in calcium homeostasis. As calcium and phosphate balances are closely linked, we hypothesized that there was a functional link between kidney NHE3 activity, calcium, and phosphate balance. Therefore, we examined calcium and phosphate homeostasis in kidney tubule-specific NHE3 knockout mice (NHE3loxloxPax8 mice). Compared to controls, these knockout mice were normocalcemic with no significant difference in urinary calcium excretion or parathyroid hormone levels. Thiazide-induced hypocalciuria was less pronounced in the knockout mice, in line with impaired proximal tubule calcium transport. Knockout mice had greater furosemide-induced calciuresis and distal tubule calcium transport pathways were enhanced. Despite lower levels of the sodium/phosphate cotransporters (NaPi)-2a and -2c, knockout mice had normal plasma phosphate, sodium-dependent 32Phosphate uptake in proximal tubule membrane vesicles and urinary phosphate excretion. Intestinal phosphate uptake was unchanged. Low dietary phosphate reduced parathyroid hormone levels and increased NaPi-2a and -2c abundances in both genotypes, but NaPi-2c levels remained lower in the knockout mice. Gene expression profiling suggested proximal tubule remodeling in the knockout mice. Acutely, indirect NHE3 inhibition using the SGLT2 inhibitor empagliflozin did not affect urinary calcium and phosphate excretion. No differences in femoral bone density or architecture were detectable in the knockout mice. Thus, a role for kidney NHE3 in calcium homeostasis can be unraveled by diuretics, but NHE3 deletion in the kidneys has no major effects on overall calcium and phosphate homeostasis due, at least in part, to compensating mechanisms.
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Affiliation(s)
- Søren B Poulsen
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Sathish K Murali
- Department of Biomedicine, Aarhus University, Aarhus, Denmark; Department of Biomedical Sciences, University of Veterinary Medicine, Vienna, Austria
| | - Linto Thomas
- Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, Florida, USA
| | - Adrienne Assmus
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Lena L Rosenbæk
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Rikke Nielsen
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Henrik Dimke
- Department of Cardiovascular and Renal Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark; Department of Nephrology, Odense University Hospital, Odense, Denmark
| | - Timo Rieg
- Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, Florida, USA; James A. Haley Veterans' Hospital, Tampa, Florida, USA.
| | - Robert A Fenton
- Department of Biomedicine, Aarhus University, Aarhus, Denmark.
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2
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Dimke H. New insights into renal calcium-sensing receptor activation. Curr Opin Nephrol Hypertens 2024; 33:433-440. [PMID: 38690798 DOI: 10.1097/mnh.0000000000000998] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/03/2024]
Abstract
PURPOSE OF REVIEW Activation of the calcium-sensing receptor (CASR) in the parathyroid gland suppresses the release of parathyroid hormone (PTH). Furthermore, activation of the renal CASR directly increases the urinary excretion of calcium, by inhibiting transepithelial calcium transport in the nephron. Gain-of-function mutations in the CASR gene lead to autosomal dominant hypocalcemia 1 (ADH1), with inappropriately low PTH levels and hypocalcemia, indicative of excessive activation of the parathyroid CASR. However, hypercalciuria is not always observed. The reason why the manifestation of hypercalciuria is not uniform among ADH1 patients is not well understood. RECENT FINDINGS Direct activation of the CASR in the kidney has been cumbersome to study, and an indirect measure to effectively estimate the degree of CASR activation following chronic hypercalcemia or genetic gain-of-function CASR activation has been lacking. Studies have shown that expression of the pore-blocking claudin-14 is strongly stimulated by the CASR in a dose-dependent manner. This stimulatory effect is abolished after renal Casr ablation in hypercalcemic mice, suggesting that claudin-14 abundance may gauge renal CASR activation. Using this marker has led to unexpected discoveries regarding renal CASR activation. SUMMARY These new studies have informed on renal CASR activation thresholds and the downstream CASR-regulated calcium transport mechanisms.
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Affiliation(s)
- Henrik Dimke
- Department of Cardiovascular and Renal Research, Institute of Molecular Medicine, University of Southern Denmark
- Department of Nephrology, Odense University Hospital, Odense, Denmark
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3
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Brideau G, Cheval L, Griveau C, Ling WME, Lievre L, Crambert G, Müller D, Broćić J, Cherchame E, Houillier P, Prot-Bertoye C. Claudin-10 Expression and the Gene Expression Pattern of Thick Ascending Limb Cells. Int J Mol Sci 2024; 25:4008. [PMID: 38612818 PMCID: PMC11011785 DOI: 10.3390/ijms25074008] [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: 01/31/2024] [Revised: 03/16/2024] [Accepted: 03/27/2024] [Indexed: 04/14/2024] Open
Abstract
Many genomic, anatomical and functional differences exist between the medullary (MTAL) and the cortical thick ascending limb of the loop of Henle (CTAL), including a higher expression of claudin-10 (CLDN10) in the MTAL than in the CTAL. Therefore, we assessed to what extent the Cldn10 gene expression is a determinant of differential gene expression between MTAL and CTAL. RNAs extracted from CTAL and MTAL microdissected from wild type (WT) and Cldn10 knock out mice (cKO) were analyzed by RNAseq. Differential and enrichment analyses (GSEA) were performed with interactive R Shiny software. Between WT and cKO MTAL, 637 genes were differentially expressed, whereas only 76 were differentially expressed between WT and cKO CTAL. Gene expression patterns and GSEA analyses in all replicates showed that WT MTAL did not cluster with the other replicates; no hierarchical clustering could be found between WT CTAL, cKO CTAL and cKO MTAL. Compared to WT replicates, cKO replicates were enriched in Cldn16, Cldn19, Pth1r, (parathyroid hormone receptor type 1), Casr (calcium sensing receptor) and Vdr (Vitamin D Receptor) mRNA in both the cortex and medulla. Cldn10 is associated with gene expression patterns, including genes specifically involved in divalent cations reabsorption in the TAL.
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Affiliation(s)
- Gaelle Brideau
- Centre de Recherche des Cordeliers, Institut National de la Santé et de la Recherche Médicale, Sorbonne Université, Université Paris Cité, F-75006 Paris, France; (G.B.); (L.C.); (C.G.); (W.-M.E.L.); (L.L.); (G.C.)
- Centre National de la Recherche Scientifique, Equipe Mixte de Recherche 8228-Laboratoire de Physiologie Rénale et Tubulopathies, F-75006 Paris, France
| | - Lydie Cheval
- Centre de Recherche des Cordeliers, Institut National de la Santé et de la Recherche Médicale, Sorbonne Université, Université Paris Cité, F-75006 Paris, France; (G.B.); (L.C.); (C.G.); (W.-M.E.L.); (L.L.); (G.C.)
- Centre National de la Recherche Scientifique, Equipe Mixte de Recherche 8228-Laboratoire de Physiologie Rénale et Tubulopathies, F-75006 Paris, France
| | - Camille Griveau
- Centre de Recherche des Cordeliers, Institut National de la Santé et de la Recherche Médicale, Sorbonne Université, Université Paris Cité, F-75006 Paris, France; (G.B.); (L.C.); (C.G.); (W.-M.E.L.); (L.L.); (G.C.)
- Centre National de la Recherche Scientifique, Equipe Mixte de Recherche 8228-Laboratoire de Physiologie Rénale et Tubulopathies, F-75006 Paris, France
| | - Wung-Man Evelyne Ling
- Centre de Recherche des Cordeliers, Institut National de la Santé et de la Recherche Médicale, Sorbonne Université, Université Paris Cité, F-75006 Paris, France; (G.B.); (L.C.); (C.G.); (W.-M.E.L.); (L.L.); (G.C.)
- Centre National de la Recherche Scientifique, Equipe Mixte de Recherche 8228-Laboratoire de Physiologie Rénale et Tubulopathies, F-75006 Paris, France
| | - Loïc Lievre
- Centre de Recherche des Cordeliers, Institut National de la Santé et de la Recherche Médicale, Sorbonne Université, Université Paris Cité, F-75006 Paris, France; (G.B.); (L.C.); (C.G.); (W.-M.E.L.); (L.L.); (G.C.)
- Centre National de la Recherche Scientifique, Equipe Mixte de Recherche 8228-Laboratoire de Physiologie Rénale et Tubulopathies, F-75006 Paris, France
| | - Gilles Crambert
- Centre de Recherche des Cordeliers, Institut National de la Santé et de la Recherche Médicale, Sorbonne Université, Université Paris Cité, F-75006 Paris, France; (G.B.); (L.C.); (C.G.); (W.-M.E.L.); (L.L.); (G.C.)
- Centre National de la Recherche Scientifique, Equipe Mixte de Recherche 8228-Laboratoire de Physiologie Rénale et Tubulopathies, F-75006 Paris, France
| | - Dominik Müller
- Department of Pediatrics, Division of Gastroenterology, Nephrology and Metabolic Diseases, Charité-Universitätsmedizin Berlin, DE-13353 Berlin, Germany;
| | - Jovana Broćić
- Paris Brain Institute (ICM), Hôpital Pitié-Salpêtrière, Inserm U 1127, CNRS UMR 7225, Sorbonne Université, Data Analysis Core Platform, F-75013 Paris, France; (J.B.); (E.C.)
| | - Emeline Cherchame
- Paris Brain Institute (ICM), Hôpital Pitié-Salpêtrière, Inserm U 1127, CNRS UMR 7225, Sorbonne Université, Data Analysis Core Platform, F-75013 Paris, France; (J.B.); (E.C.)
| | - Pascal Houillier
- Centre de Recherche des Cordeliers, Institut National de la Santé et de la Recherche Médicale, Sorbonne Université, Université Paris Cité, F-75006 Paris, France; (G.B.); (L.C.); (C.G.); (W.-M.E.L.); (L.L.); (G.C.)
- Centre National de la Recherche Scientifique, Equipe Mixte de Recherche 8228-Laboratoire de Physiologie Rénale et Tubulopathies, F-75006 Paris, France
- Assistance Publique-Hôpitaux de Paris, Hôpital Européen Georges Pompidou, Service de Physiologie, F-75015 Paris, France
- Centre de Référence des Maladies Rénales Héréditaires de l’Enfant et de l’Adulte (MARHEA), The European Rare Kidney Disease Reference Network (ERKNet), F-75015 Paris, France
- Centre de Référence des Maladies Rares du Calcium et du Phosphate, The European Reference Network on Rare Endocrine Conditions (Endo-ERN), F-75015 Paris, France
- Faculté de Médecine, Université Paris Cité, F-75006 Paris, France
| | - Caroline Prot-Bertoye
- Centre de Recherche des Cordeliers, Institut National de la Santé et de la Recherche Médicale, Sorbonne Université, Université Paris Cité, F-75006 Paris, France; (G.B.); (L.C.); (C.G.); (W.-M.E.L.); (L.L.); (G.C.)
- Centre National de la Recherche Scientifique, Equipe Mixte de Recherche 8228-Laboratoire de Physiologie Rénale et Tubulopathies, F-75006 Paris, France
- Assistance Publique-Hôpitaux de Paris, Hôpital Européen Georges Pompidou, Service de Physiologie, F-75015 Paris, France
- Centre de Référence des Maladies Rénales Héréditaires de l’Enfant et de l’Adulte (MARHEA), The European Rare Kidney Disease Reference Network (ERKNet), F-75015 Paris, France
- Centre de Référence des Maladies Rares du Calcium et du Phosphate, The European Reference Network on Rare Endocrine Conditions (Endo-ERN), F-75015 Paris, France
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Yousef Yengej FA, Pou Casellas C, Ammerlaan CME, Olde Hanhof CJA, Dilmen E, Beumer J, Begthel H, Meeder EMG, Hoenderop JG, Rookmaaker MB, Verhaar MC, Clevers H. Tubuloid differentiation to model the human distal nephron and collecting duct in health and disease. Cell Rep 2024; 43:113614. [PMID: 38159278 DOI: 10.1016/j.celrep.2023.113614] [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: 08/14/2023] [Revised: 11/09/2023] [Accepted: 12/06/2023] [Indexed: 01/03/2024] Open
Abstract
Organoid technology is rapidly gaining ground for studies on organ (patho)physiology. Tubuloids are long-term expanding organoids grown from adult kidney tissue or urine. The progenitor state of expanding tubuloids comes at the expense of differentiation. Here, we differentiate tubuloids to model the distal nephron and collecting ducts, essential functional parts of the kidney. Differentiation suppresses progenitor traits and upregulates genes required for function. A single-cell atlas reveals that differentiation predominantly generates thick ascending limb and principal cells. Differentiated human tubuloids express luminal NKCC2 and ENaC capable of diuretic-inhibitable electrolyte uptake and enable disease modeling as demonstrated by a lithium-induced tubulopathy model. Lithium causes hallmark AQP2 loss, induces proliferation, and upregulates inflammatory mediators, as seen in vivo. Lithium also suppresses electrolyte transport in multiple segments. In conclusion, this tubuloid model enables modeling of the human distal nephron and collecting duct in health and disease and provides opportunities to develop improved therapies.
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Affiliation(s)
- Fjodor A Yousef Yengej
- Hubrecht Institute for Developmental Biology and Stem Cell Research-KNAW & University Medical Center Utrecht, 3584 CT Utrecht, the Netherlands; Department of Nephrology and Hypertension, University Medical Center Utrecht, 3584 CX Utrecht, the Netherlands
| | - Carla Pou Casellas
- Hubrecht Institute for Developmental Biology and Stem Cell Research-KNAW & University Medical Center Utrecht, 3584 CT Utrecht, the Netherlands; Department of Nephrology and Hypertension, University Medical Center Utrecht, 3584 CX Utrecht, the Netherlands
| | - Carola M E Ammerlaan
- Hubrecht Institute for Developmental Biology and Stem Cell Research-KNAW & University Medical Center Utrecht, 3584 CT Utrecht, the Netherlands; Department of Nephrology and Hypertension, University Medical Center Utrecht, 3584 CX Utrecht, the Netherlands
| | - Charlotte J A Olde Hanhof
- Department of Medical BioSciences, Radboud Institute for Medical Innovation, 6525 GA Nijmegen, the Netherlands
| | - Emre Dilmen
- Department of Medical BioSciences, Radboud Institute for Medical Innovation, 6525 GA Nijmegen, the Netherlands
| | - Joep Beumer
- Hubrecht Institute for Developmental Biology and Stem Cell Research-KNAW, 3584 CT Utrecht, the Netherlands; Institute of Human Biology, Roche Pharma Research and Early Development, 4058 Basel, Switzerland
| | - Harry Begthel
- Hubrecht Institute for Developmental Biology and Stem Cell Research-KNAW, 3584 CT Utrecht, the Netherlands
| | - Elise M G Meeder
- Department of Psychiatry, Radboud University Medical Center, 6525 GA Nijmegen, the Netherlands
| | - Joost G Hoenderop
- Department of Medical BioSciences, Radboud Institute for Medical Innovation, 6525 GA Nijmegen, the Netherlands
| | - Maarten B Rookmaaker
- Department of Nephrology and Hypertension, University Medical Center Utrecht, 3584 CX Utrecht, the Netherlands
| | - Marianne C Verhaar
- Department of Nephrology and Hypertension, University Medical Center Utrecht, 3584 CX Utrecht, the Netherlands.
| | - Hans Clevers
- Hubrecht Institute for Developmental Biology and Stem Cell Research-KNAW & University Medical Center Utrecht, 3584 CT Utrecht, the Netherlands; Oncode Institute, Hubrecht Institute-KNAW, 3584 CT Utrecht, the Netherlands.
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5
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Rungrasameviriya P, Santilinon A, Atichartsintop P, Hadpech S, Thongboonkerd V. Tight junction and kidney stone disease. Tissue Barriers 2024; 12:2210051. [PMID: 37162265 PMCID: PMC10832927 DOI: 10.1080/21688370.2023.2210051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Accepted: 04/30/2023] [Indexed: 05/11/2023] Open
Abstract
Defects of tight junction (TJ) are involved in many diseases related to epithelial cell functions, including kidney stone disease (KSD), which is a common disease affecting humans for over a thousand years. This review provides brief overviews of KSD and TJ, and summarizes the knowledge on crystal-induced defects of TJ in renal tubular epithelial cells (RTECs) in KSD. Calcium oxalate (CaOx) crystals, particularly COM, disrupt TJ via p38 MAPK and ROS/Akt/p38 MAPK signaling pathways, filamentous actin (F-actin) reorganization and α-tubulin relocalization. Stabilizing p38 MAPK signaling, reactive oxygen species (ROS) production, F-actin and α-tubulin by using SB239063, N-acetyl-L-cysteine (NAC), phalloidin and docetaxel, respectively, successfully prevent the COM-induced TJ disruption and malfunction. Additionally, genetic disorders of renal TJ, including mutations and single nucleotide polymorphisms (SNPs) of CLDN2, CLDN10b, CLDN14, CLDN16 and CLDN19, also affect KSD. Finally, the role of TJ as a potential target for KSD therapeutics and prevention is also discussed.
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Affiliation(s)
- Papart Rungrasameviriya
- Nawamethee Project, Doctor of Medicine Program, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Aticha Santilinon
- Nawamethee Project, Doctor of Medicine Program, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Palita Atichartsintop
- Nawamethee Project, Doctor of Medicine Program, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Sudarat Hadpech
- Medical Proteomics Unit, Research Department, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Visith Thongboonkerd
- Medical Proteomics Unit, Research Department, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
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Dimke H, Griveau C, Ling WME, Brideau G, Cheval L, Muthan P, Müller D, Al-Shebel A, Houillier P, Prot-Bertoye C. Claudin-19 localizes to the thick ascending limb where its expression is required for junctional claudin-16 localization. Ann N Y Acad Sci 2023; 1526:126-137. [PMID: 37344378 DOI: 10.1111/nyas.15014] [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] [Indexed: 06/23/2023]
Abstract
The kidney is critical for mineral homeostasis. Calcium and magnesium reabsorption in the renal thick ascending limb (TAL) involves claudin-16 (CLDN16) and claudin-19 (CLDN19) and pathogenic variants in either gene lead to familial hypomagnesemia with hypercalciuria and nephrocalcinosis (FHHNC) with severe calcium and magnesium wasting. While both CLDN16 and CLDN19 localize to the TAL, varying expression patterns in the renal tubule have been reported using different antibodies. We, therefore, studied the localization of CLDN19 in the kidneys of wild-type and Cldn19-deleted mice using three anti-CLDN19 antibodies and examined the role of Cldn19 deletion on CLDN16 and CLDN10 localization. We find that CLDN19 localizes to basolateral membrane domains of the medullary and cortical TAL but only to the tight junction of TALs in the outer stripe of outer medulla and cortex, where it colocalizes with CLDN16. Furthermore, in TALs from Cldn19-deleted mice, CLDN16 is expressed in basolateral membrane domains but not at the tight junction. In contrast, Cldn19 ablation does not change CLDN10 localization. These findings directly implicate CLDN19 in regulating permeability in the TAL by allowing junctional insertion of CLDN16 and may explain the shared renal phenotypic characteristics in FHHNC patients.
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Affiliation(s)
- Henrik Dimke
- Department of Cardiovascular and Renal Research, University of Southern Denmark, Odense, Denmark
- Department of Nephrology, Odense University Hospital, Odense, Denmark
| | - Camille Griveau
- Centre de Recherche des Cordeliers, INSERM, Sorbonne Université, Université Paris Cité, Paris, France
- CNRS EMR 8228 - Laboratoire de Physiologie Rénale et Tubulopathies, Paris, France
| | - Wung-Man Evelyne Ling
- Centre de Recherche des Cordeliers, INSERM, Sorbonne Université, Université Paris Cité, Paris, France
- CNRS EMR 8228 - Laboratoire de Physiologie Rénale et Tubulopathies, Paris, France
| | - Gaelle Brideau
- Centre de Recherche des Cordeliers, INSERM, Sorbonne Université, Université Paris Cité, Paris, France
- CNRS EMR 8228 - Laboratoire de Physiologie Rénale et Tubulopathies, Paris, France
| | - Lydie Cheval
- Centre de Recherche des Cordeliers, INSERM, Sorbonne Université, Université Paris Cité, Paris, France
- CNRS EMR 8228 - Laboratoire de Physiologie Rénale et Tubulopathies, Paris, France
| | - Pravina Muthan
- Centre de Recherche des Cordeliers, INSERM, Sorbonne Université, Université Paris Cité, Paris, France
- CNRS EMR 8228 - Laboratoire de Physiologie Rénale et Tubulopathies, Paris, France
| | - Dominik Müller
- Division of Gastroenterology, Nephrology and Metabolic Diseases, Department of Pediatrics, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Amr Al-Shebel
- Division of Gastroenterology, Nephrology and Metabolic Diseases, Department of Pediatrics, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Pascal Houillier
- Centre de Recherche des Cordeliers, INSERM, Sorbonne Université, Université Paris Cité, Paris, France
- CNRS EMR 8228 - Laboratoire de Physiologie Rénale et Tubulopathies, Paris, France
- Assistance Publique-Hôpitaux de Paris, Hôpital Européen Georges Pompidou, Service de Physiologie, Paris, France
- Centre de Référence des Maladies Rénales Héréditaires de l'Enfant et de l'Adulte (MARHEA), Paris, France
- Centre de Référence des Maladies Rares du Calcium et du Phosphate, Paris, France
| | - Caroline Prot-Bertoye
- Centre de Recherche des Cordeliers, INSERM, Sorbonne Université, Université Paris Cité, Paris, France
- CNRS EMR 8228 - Laboratoire de Physiologie Rénale et Tubulopathies, Paris, France
- Assistance Publique-Hôpitaux de Paris, Hôpital Européen Georges Pompidou, Service de Physiologie, Paris, France
- Centre de Référence des Maladies Rénales Héréditaires de l'Enfant et de l'Adulte (MARHEA), Paris, France
- Centre de Référence des Maladies Rares du Calcium et du Phosphate, Paris, France
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7
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Alexander RT, Dimke H. Molecular mechanisms underlying paracellular calcium and magnesium reabsorption in the proximal tubule and thick ascending limb. Ann N Y Acad Sci 2022; 1518:69-83. [PMID: 36200584 DOI: 10.1111/nyas.14909] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Calcium and magnesium are the most abundant divalent cations in the body. The plasma level is controlled by coordinated interaction between intestinal absorption, reabsorption in the kidney, and, for calcium at least, bone storage and exchange. The kidney adjusts urinary excretion of these ions in response to alterations in their systemic concentration. Free ionized and anion-complexed calcium and magnesium are filtered at the glomerulus. The majority (i.e., >85%) of filtered divalent cations are reabsorbed via paracellular pathways from the proximal tubule and thick ascending limb (TAL) of the loop of Henle. Interestingly, the largest fraction of filtered calcium is reabsorbed from the proximal tubule (65%), while the largest fraction of filtered magnesium is reclaimed from the TAL (60%). The paracellular pathways mediating these fluxes are composed of tight junctional pores formed by claudins. In the proximal tubule, claudin-2 and claudin-12 confer calcium permeability, while the exact identity of the magnesium pore remains to be determined. Claudin-16 and claudin-19 contribute to the calcium and magnesium permeable pathway in the TAL. In this review, we discuss the data supporting these conclusions and speculate as to why there is greater fractional calcium reabsorption from the proximal tubule and greater fractional magnesium reabsorption from the TAL.
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Affiliation(s)
- R Todd Alexander
- Departments of Physiology & Pediatrics, University of Alberta, Edmonton, Alberta, Canada.,Women's and Children's Health Institute, Edmonton, Alberta, Canada
| | - Henrik Dimke
- Department of Cardiovascular and Renal Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Demark.,Department of Nephrology, Odense University Hospital, Odense, Denmark
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8
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Partridge BR, Kani Y, Lorenzo MF, Campelo SN, Allen IC, Hinckley J, Hsu FC, Verbridge SS, Robertson JL, Davalos RV, Rossmeisl JH. High-Frequency Irreversible Electroporation (H-FIRE) Induced Blood-Brain Barrier Disruption Is Mediated by Cytoskeletal Remodeling and Changes in Tight Junction Protein Regulation. Biomedicines 2022; 10:1384. [PMID: 35740406 PMCID: PMC9220673 DOI: 10.3390/biomedicines10061384] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2022] [Revised: 06/07/2022] [Accepted: 06/09/2022] [Indexed: 12/25/2022] Open
Abstract
Glioblastoma is the deadliest malignant brain tumor. Its location behind the blood-brain barrier (BBB) presents a therapeutic challenge by preventing effective delivery of most chemotherapeutics. H-FIRE is a novel tumor ablation method that transiently disrupts the BBB through currently unknown mechanisms. We hypothesized that H-FIRE mediated BBB disruption (BBBD) occurs via cytoskeletal remodeling and alterations in tight junction (TJ) protein regulation. Intracranial H-FIRE was delivered to Fischer rats prior to sacrifice at 1-, 24-, 48-, 72-, and 96 h post-treatment. Cytoskeletal proteins and native and ubiquitinated TJ proteins (TJP) were evaluated using immunoprecipitation, Western blotting, and gene-expression arrays on treated and sham control brain lysates. Cytoskeletal and TJ protein expression were further evaluated with immunofluorescent microscopy. A decrease in the F/G-actin ratio, decreased TJP concentrations, and increased ubiquitination of TJP were observed 1-48 h post-H-FIRE compared to sham controls. By 72-96 h, cytoskeletal and TJP expression recovered to pretreatment levels, temporally corresponding with increased claudin-5 and zonula occludens-1 gene expression. Ingenuity pathway analysis revealed significant dysregulation of claudin genes, centered around claudin-6 in H-FIRE treated rats. In conclusion, H-FIRE is capable of permeating the BBB in a spatiotemporal manner via cytoskeletal-mediated TJP modulation. This minimally invasive technology presents with applications for localized and long-lived enhanced intracranial drug delivery.
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Affiliation(s)
- Brittanie R. Partridge
- Department of Small Animal Clinical Sciences, Virginia Tech, Blacksburg, VA 24061, USA; (B.R.P.); (Y.K.); (J.H.)
| | - Yukitaka Kani
- Department of Small Animal Clinical Sciences, Virginia Tech, Blacksburg, VA 24061, USA; (B.R.P.); (Y.K.); (J.H.)
| | - Melvin F. Lorenzo
- Department of Biomedical Engineering and Mechanics, Virginia Tech, Blacksburg, VA 24061, USA; (M.F.L.); (S.N.C.)
| | - Sabrina N. Campelo
- Department of Biomedical Engineering and Mechanics, Virginia Tech, Blacksburg, VA 24061, USA; (M.F.L.); (S.N.C.)
| | - Irving C. Allen
- Department of Biomedical Sciences and Pathobiology, Virginia Tech, Blacksburg, VA 24061, USA; (I.C.A.); (S.S.V.); (J.L.R.); (R.V.D.)
- Center of Engineered Health, Virginia Tech, Blacksburg, VA 24061, USA
| | - Jonathan Hinckley
- Department of Small Animal Clinical Sciences, Virginia Tech, Blacksburg, VA 24061, USA; (B.R.P.); (Y.K.); (J.H.)
| | - Fang-Chi Hsu
- Department of Biostatistics and Data Sciences, Division of Public Health Sciences, Wake Forest University School of Medicine, Winston-Salem, NC 27101, USA;
| | - Scott S. Verbridge
- Department of Biomedical Sciences and Pathobiology, Virginia Tech, Blacksburg, VA 24061, USA; (I.C.A.); (S.S.V.); (J.L.R.); (R.V.D.)
- Center of Engineered Health, Virginia Tech, Blacksburg, VA 24061, USA
| | - John L. Robertson
- Department of Biomedical Sciences and Pathobiology, Virginia Tech, Blacksburg, VA 24061, USA; (I.C.A.); (S.S.V.); (J.L.R.); (R.V.D.)
| | - Rafael V. Davalos
- Department of Biomedical Engineering and Mechanics, Virginia Tech, Blacksburg, VA 24061, USA; (M.F.L.); (S.N.C.)
- Center of Engineered Health, Virginia Tech, Blacksburg, VA 24061, USA
| | - John H. Rossmeisl
- Department of Small Animal Clinical Sciences, Virginia Tech, Blacksburg, VA 24061, USA; (B.R.P.); (Y.K.); (J.H.)
- Center of Engineered Health, Virginia Tech, Blacksburg, VA 24061, USA
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9
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van Megen WH, Tan RSG, Alexander RT, Dimke H. Differential parathyroid and kidney Ca 2+-sensing receptor activation in autosomal dominant hypocalcemia 1. EBioMedicine 2022; 78:103947. [PMID: 35313217 PMCID: PMC8935519 DOI: 10.1016/j.ebiom.2022.103947] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Revised: 02/11/2022] [Accepted: 03/03/2022] [Indexed: 12/04/2022] Open
Abstract
Background Parathyroid Ca2+-sensing receptor (CaSR) activation inhibits parathyroid hormone (PTH) release, while activation of renal CaSRs attenuates Ca2+ transport and increases expression of the pore-blocking claudin-14. Patients with autosomal dominant hypocalcemia 1 (ADH1), due to activating CASR mutations, exhibit hypocalcemia but not always hypercalciuria (elevated Ca2+ in urine). The latter promotes nephrocalcinosis and renal insufficiency. Although CaSRs throughout the body including the kidney harbor activating CASR mutations, it is not understood why only some ADH1 patients display hypercalciuria. Methods Activation of the CaSR was studied in mouse models and a ADH1 patient. In vitro CaSR activation was studied in HEK293 cells. Findings Cldn14 showed blood Ca2+ concentration-dependent regulation, which was absent in mice with kidney-specific Casr deletion, indicating Cldn14 is a suitable marker for chronic CaSR activation in the kidney. Mice with a gain-of-function mutation in the Casr (Nuf) were hypocalcemic with low plasma PTH levels. However, renal CaSRs were not activated at baseline but only after normalizing blood Ca2+ levels. Similarly, significant hypercalciuria was not observed in a ADH1 patient until blood Ca2+ was normalized. In vitro experiments indicate that increased CaSR expression in the parathyroid relative to the kidney could contribute to tissue-specific CaSR activation thresholds. Interpretation Our findings suggest that parathyroid CaSR overactivity can reduce plasma Ca2+ to levels insufficient to activate renal CaSRs, even when an activating mutation is present. These findings identify a conceptually new mechanism of CaSR-dependent Ca2+ balance regulation that aid in explaining the spectrum of hypercalciuria in ADH1 patients. Funding Erasmus+ 2018/E+/4458087, the Canadian Institutes for Health research, the Novo Nordisk Foundation, the Beckett Foundation, the Carlsberg Foundation and Independent Research Fund Denmark.
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Affiliation(s)
- Wouter H van Megen
- Department of Cardiovascular and Renal Research, Institute of Molecular Medicine, University of Southern Denmark, J.B. Winsløws Vej 21, 3rd floor, 5000 Odense C, Denmark; Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Rebecca Siu Ga Tan
- Membrane Protein Disease Research Group, Department of Physiology, University of Alberta, Edmonton, Canada; The Women's and Children's Health Research Institute, Edmonton, Alberta, Canada
| | - R Todd Alexander
- Membrane Protein Disease Research Group, Department of Physiology, University of Alberta, Edmonton, Canada; The Women's and Children's Health Research Institute, Edmonton, Alberta, Canada; Department of Pediatrics, 4-585 Edmonton Clinic Health Academy, University of Alberta, 11405 87th Avenue, Edmonton, Alberta T6G 2R7, Canada.
| | - Henrik Dimke
- Department of Cardiovascular and Renal Research, Institute of Molecular Medicine, University of Southern Denmark, J.B. Winsløws Vej 21, 3rd floor, 5000 Odense C, Denmark; Department of Nephrology, Odense University Hospital, Denmark.
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10
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van Megen WH, Beggs MR, An SW, Ferreira PG, Lee JJ, Wolf MT, Alexander RT, Dimke H. Gentamicin Inhibits Ca 2+ Channel TRPV5 and Induces Calciuresis Independent of the Calcium-Sensing Receptor-Claudin-14 Pathway. J Am Soc Nephrol 2022; 33:547-564. [PMID: 35022312 PMCID: PMC8975070 DOI: 10.1681/asn.2021030392] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Accepted: 12/19/2021] [Indexed: 11/03/2022] Open
Abstract
BACKGROUND Treatment with the aminoglycoside antibiotic gentamicin can be associated with severe adverse effects, including renal Ca2+ wasting. The underlying mechanism is unknown but it has been proposed to involve activation of the Ca2+-sensing receptor (CaSR) in the thick ascending limb, which would increase expression of claudin-14 (CLDN14) and limit Ca2+ reabsorption. However, no direct evidence for this hypothesis has been presented. METHODS We studied the effect of gentamicin in vivo using mouse models with impaired Ca2+ reabsorption in the proximal tubule and the thick ascending limb. We used a Cldn14 promoter luciferase reporter assay to study CaSR activation and investigated the effect of gentamicin on activity of the distal nephron Ca2+ channel transient receptor potential vanilloid 5 (TRPV5), as determined by patch clamp in HEK293 cells. RESULTS Gentamicin increased urinary Ca2+ excretion in wild-type mice after acute and chronic administration. This calciuretic effect was unaltered in mice with genetic CaSR overactivation and was present in furosemide-treated animals, whereas the calciuretic effect in Cldn14-/- mice and mice with impaired proximal tubular Ca2+ reabsorption (claudin-2 [CLDN2]-deficient Cldn2-/- mice) was equivalent to that of wild-type mice. In vitro, gentamicin failed to activate the CaSR. In contrast, patch clamp analysis revealed that gentamicin strongly inhibited rabbit and human TRPV5 activity and chronic gentamicin administration downregulated distal nephron Ca2+ transporters. CONCLUSIONS Gentamicin does not cause hypercalciuria via activation of the CaSR-CLDN14 pathway or by interfering with proximal tubular CLDN2-dependent Ca2+ reabsorption. Instead, gentamicin blocks distal Ca2+ reabsorption by direct inhibition of the Ca2+ channel TRPV5. These findings offer new insights into Ca2+ wasting in patients treated with gentamicin.
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Affiliation(s)
- Wouter H. van Megen
- Department of Cardiovascular and Renal Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark
| | - Megan R. Beggs
- Department of Physiology, University of Alberta, Canada,Women and Children's Health Institute, Alberta, Canada
| | - Sung-Wan An
- Department of Pediatrics, Division of Pediatric Nephrology, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Patrícia G. Ferreira
- Department of Cardiovascular and Renal Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark
| | - Justin J. Lee
- Department of Physiology, University of Alberta, Canada
| | - Matthias T. Wolf
- Department of Pediatrics, Division of Pediatric Nephrology, University of Texas Southwestern Medical Center, Dallas, Texas
| | - R. Todd Alexander
- Department of Physiology, University of Alberta, Canada,Women and Children's Health Institute, Alberta, Canada,Department of Pediatrics, University of Alberta, Canada
| | - Henrik Dimke
- Department of Cardiovascular and Renal Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark .,Department of Nephrology, Odense University Hospital, Denmark
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11
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Calcium and Vitamin D Supplementation and Their Association with Kidney Stone Disease: A Narrative Review. Nutrients 2021; 13:nu13124363. [PMID: 34959915 PMCID: PMC8707627 DOI: 10.3390/nu13124363] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Revised: 11/30/2021] [Accepted: 11/30/2021] [Indexed: 01/03/2023] Open
Abstract
Kidney stone disease is a multifactorial condition influenced by both genetic predisposition and environmental factors such as lifestyle and dietary habits. Although different monogenic polymorphisms have been proposed as playing a causal role for calcium nephrolithiasis, the prevalence of these mutations in the general population and their complete pathogenetic pathway is yet to be determined. General dietary advice for kidney stone formers includes elevated fluid intake, dietary restriction of sodium and animal proteins, avoidance of a low calcium diet, maintenance of a normal body mass index, and elevated intake of vegetables and fibers. Thus, balanced calcium consumption protects against the risk for kidney stones by reducing intestinal oxalate availability and its urinary excretion. However, calcium supplementation given between meals might increase urinary calcium excretion without the beneficial effect on oxalate. In kidney stone formers, circulating active vitamin D has been found to be increased, whereas higher plasma 25-hydroxycholecalciferol seems to be present only in hypercalciuric patients. The association between nutritional vitamin D supplements and the risk for stone formation is currently not completely understood. However, taken together, available evidence might suggest that vitamin D administration worsens the risk for stone formation in patients predisposed to hypercalciuria. In this review, we analyzed and discussed available literature on the effect of calcium and vitamin D supplementation on the risk for kidney stone formation.
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12
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Beggs MR, Young K, Pan W, O'Neill DD, Saurette M, Plain A, Rievaj J, Doschak MR, Cordat E, Dimke H, Alexander RT. Claudin-2 and claudin-12 form independent, complementary pores required to maintain calcium homeostasis. Proc Natl Acad Sci U S A 2021; 118:e2111247118. [PMID: 34810264 PMCID: PMC8694054 DOI: 10.1073/pnas.2111247118] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/18/2021] [Indexed: 12/29/2022] Open
Abstract
Calcium (Ca2+) homeostasis is maintained through coordination between intestinal absorption, renal reabsorption, and bone remodeling. Intestinal and renal (re)absorption occurs via transcellular and paracellular pathways. The latter contributes the bulk of (re)absorption under conditions of adequate intake. Epithelial paracellular permeability is conferred by tight-junction proteins called claudins. However, the molecular identity of the paracellular Ca2+ pore remains to be delineated. Claudins (Cldn)-2 and -12 confer Ca2+ permeability, but deletion of either claudin does not result in a negative Ca2+ balance or increased calciotropic hormone levels, suggesting the existence of additional transport pathways or parallel roles for the two claudins. To test this, we generated a Cldn2/12 double knockout mouse (DKO). These animals have reduced intestinal Ca2+ absorption. Colonic Ca2+ permeability is also reduced in DKO mice and significantly lower than single-null animals, while small intestine Ca2+ permeability is unaltered. The DKO mice display significantly greater urinary Ca2+ wasting than Cldn2 null animals. These perturbations lead to hypocalcemia and reduced bone mineral density, which was not observed in single-KO animals. Both claudins were localized to colonic epithelial crypts and renal proximal tubule cells, but they do not physically interact in vitro. Overexpression of either claudin increased Ca2+ permeability in cell models with endogenous expression of the other claudin. We find claudin-2 and claudin-12 form partially redundant, independent Ca2+ permeable pores in renal and colonic epithelia that enable paracellular Ca2+ (re)absorption in these segments, with either one sufficient to maintain Ca2+ balance.
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Affiliation(s)
- Megan R Beggs
- Department of Physiology, University of Alberta, Edmonton, AB, T6G 2H7, Canada
- Women's and Children's Health Research Institute, Edmonton, AB, T6G 1C9, Canada
| | - Kennedi Young
- Department of Physiology, University of Alberta, Edmonton, AB, T6G 2H7, Canada
| | - Wanling Pan
- Department of Physiology, University of Alberta, Edmonton, AB, T6G 2H7, Canada
| | - Debbie D O'Neill
- Department of Physiology, University of Alberta, Edmonton, AB, T6G 2H7, Canada
| | - Matthew Saurette
- Department of Physiology, University of Alberta, Edmonton, AB, T6G 2H7, Canada
| | - Allein Plain
- Department of Physiology, University of Alberta, Edmonton, AB, T6G 2H7, Canada
| | - Juraj Rievaj
- Department of Physiology, University of Alberta, Edmonton, AB, T6G 2H7, Canada
| | - Michael R Doschak
- Faculty of Pharmacy & Pharmaceutical Sciences, University of Alberta, Edmonton, AB, T6G 2H5, Canada
| | - Emmanuelle Cordat
- Department of Physiology, University of Alberta, Edmonton, AB, T6G 2H7, Canada
| | - Henrik Dimke
- Department of Cardiovascular and Renal Research, Institute of Molecular Medicine, University of Southern Denmark, 5000 Odense, Denmark
- Department of Nephrology, Odense University Hospital, 5000 Odense, Denmark
| | - R Todd Alexander
- Department of Physiology, University of Alberta, Edmonton, AB, T6G 2H7, Canada;
- Women's and Children's Health Research Institute, Edmonton, AB, T6G 1C9, Canada
- Department of Pediatrics, University of Alberta, Edmonton, AB, T6G 1C9, Canada
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13
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Abstract
Nephrolithiasis is a worldwide problem with increasing prevalence, enormous costs, and significant morbidity. Calcium-containing kidney stones are by far the most common kidney stones encountered in clinical practice. Consequently, hypercalciuria is the greatest risk factor for kidney stone formation. Hypercalciuria can result from enhanced intestinal absorption, increased bone resorption, or altered renal tubular transport. Kidney stone formation is complex and driven by high concentrations of calcium-oxalate or calcium-phosphate in the urine. After discussing the mechanism mediating renal calcium salt precipitation, we review recent discoveries in renal tubular calcium transport from the proximal tubule, thick ascending limb, and distal convolution. Furthermore, we address how calcium is absorbed from the intestine and mobilized from bone. The effect of acidosis on bone calcium resorption and urinary calcium excretion is also considered. Although recent discoveries provide insight into these processes, much remains to be understood in order to provide improved therapies for hypercalciuria and prevent kidney stone formation. Expected final online publication date for the Annual Review of Physiology, Volume 84 is February 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- R T Alexander
- Departments of Physiology and Pediatrics, University of Alberta, Edmonton, Canada; .,Membrane Protein Disease Research Group, University of Alberta, Edmonton, Canada
| | - D G Fuster
- Department of Nephrology and Hypertension, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - H Dimke
- Department of Cardiovascular and Renal Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark.,Department of Nephrology, Odense University Hospital, Odense, Denmark
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14
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The Role of Diet in Bone and Mineral Metabolism and Secondary Hyperparathyroidism. Nutrients 2021; 13:nu13072328. [PMID: 34371838 PMCID: PMC8308808 DOI: 10.3390/nu13072328] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Revised: 07/02/2021] [Accepted: 07/05/2021] [Indexed: 12/13/2022] Open
Abstract
Bone disorders are a common complication of chronic kidney disease (CKD), obesity and gut malabsorption. Secondary hyperparathyroidism (SHPT) is defined as an appropriate increase in parathyroid hormone (PTH) secretion, driven by either reduced serum calcium or increased phosphate concentrations, due to an underlying condition. The available evidence on the effects of dietary advice on secondary hyperparathyroidism confirms the benefit of a diet characterized by decreased phosphate intake, avoiding low calcium and vitamin D consumption (recommended intakes 1000-1200 mg/day and 400-800 UI/day, respectively). In addition, low protein intake in CKD patients is associated with a better control of SHPT risk factors, although its strength in avoiding hyperphosphatemia and the resulting outcomes are debated, mostly for dialyzed patients. Ultimately, a consensus on the effect of dietary acid loads in the prevention of SHPT is still lacking. In conclusion, a reasonable approach for reducing the risk for secondary hyperparathyroidism is to individualize dietary manipulation based on existing risk factors and concomitant medical conditions. More studies are needed to evaluate long-term outcomes of a balanced diet on the management and prevention of secondary hyperparathyroidism in at-risk patients at.
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15
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Tan RSG, Lee CHL, Dimke H, Todd Alexander R. The role of calcium-sensing receptor signaling in regulating transepithelial calcium transport. Exp Biol Med (Maywood) 2021; 246:2407-2419. [PMID: 33926258 DOI: 10.1177/15353702211010415] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The calcium-sensing receptor (CaSR) plays a critical role in sensing extracellular calcium (Ca2+) and signaling to maintain Ca2+ homeostasis. In the parathyroid, the CaSR regulates secretion of parathyroid hormone, which functions to increase extracellular Ca2+ levels. The CaSR is also located in other organs imperative to Ca2+ homeostasis including the kidney and intestine, where it modulates Ca2+ reabsorption and absorption, respectively. In this review, we describe CaSR expression and its function in transepithelial Ca2+ transport in the kidney and intestine. Activation of the CaSR leads to G protein dependent and independent signaling cascades. The known CaSR signal transduction pathways involved in modulating paracellular and transcellular epithelial Ca2+ transport are discussed. Mutations in the CaSR cause a range of diseases that manifest in altered serum Ca2+ levels. Gain-of-function mutations in the CaSR result in autosomal dominant hypocalcemia type 1, while loss-of-function mutations cause familial hypocalciuric hypercalcemia. Additionally, the putative serine protease, FAM111A, is discussed as a potential regulator of the CaSR because mutations in FAM111A cause Kenny Caffey syndrome type 2, gracile bone dysplasia, and osteocraniostenosis, diseases that are characterized by hypocalcemia, hypoparathyroidism, and bony abnormalities, i.e. share phenotypic features of autosomal dominant hypocalcemia. Recent work has helped to elucidate the effect of CaSR signaling cascades on downstream proteins involved in Ca2+ transport across renal and intestinal epithelia; however, much remains to be discovered.
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Affiliation(s)
- Rebecca Siu Ga Tan
- Department of Physiology, University of Alberta, Edmonton T6G 1C9, Canada.,Membrane Protein Disease Research Group, University of Alberta, Edmonton T6G 1C9, Canada
| | | | - Henrik Dimke
- Department of Cardiovascular and Renal Research, Institute of Molecular Medicine, University of Southern Denmark, Odense 5000, Denmark.,Department of Nephrology, Odense University Hospital, Odense 5000, Denmark
| | - R Todd Alexander
- Department of Physiology, University of Alberta, Edmonton T6G 1C9, Canada.,Membrane Protein Disease Research Group, University of Alberta, Edmonton T6G 1C9, Canada.,Department of Pediatrics, University of Alberta, Edmonton T6G 1C9, Canada
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16
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Ferreira PG, van Megen WH, Tan R, Lee CHL, Svenningsen P, Alexander RT, Dimke H. Renal claudin-14 expression is not required for regulating Mg 2+ balance in mice. Am J Physiol Renal Physiol 2021; 320:F897-F907. [PMID: 33818126 DOI: 10.1152/ajprenal.00590.2020] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The kidneys play a crucial role in maintaining Ca2+ and Mg2+ homeostasis by regulating these minerals' reabsorption. In the thick ascending limb of Henle's loop (TAL), Ca2+ and Mg2+ are reabsorbed through the tight junctions by a shared paracellular pathway formed by claudin-16 and claudin-19. Hypercalcemia activates the Ca2+-sensing receptor (CaSR) in the TAL, causing upregulation of pore-blocking claudin-14 (CLDN14), which reduces Ca2+ and Mg2+ reabsorption from this segment. In addition, a high-Mg2+ diet is known to increase both urinary Mg2+ and Ca2+ excretion. Since Mg2+ may also activate CaSR, we aimed to investigate whether CaSR-dependent increases in CLDN14 expression also regulate urinary Mg2+ excretion in response to hypermagnesemia. Here, we show that a Mg2+-enriched diet increased urinary Mg2+ and Ca2+ excretion in mice; however, this occurred without detectable changes in renal CLDN14 expression. The administration of a high-Mg2+ diet to Cldn14-/- mice did not cause more pronounced hypermagnesemia or significantly alter urinary Mg2+ excretion. Finally, in vitro evaluation of CaSR-driven Cldn14 promoter activity in response to increasing Mg2+ concentrations revealed that Cldn14 expression only increases at supraphysiological extracellular Mg2+ levels. Together, these results suggest that CLDN14 is not involved in regulating extracellular Mg2+ balance following high dietary Mg2+ intake.NEW & NOTEWORTHY Using transgenic models and in vitro assays, this study examined the effect of Mg2+ on regulating urinary excretion of Ca2+ and Mg2+ via activation of the Ca2+-sensing receptor-claudin 14 (CLDN14) pathway. The study suggests that CLDN14 is unlikely to play a significant role in the compensatory response to hypermagnesemia.
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Affiliation(s)
- Patrícia G Ferreira
- Department of Cardiovascular and Renal Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark
| | - Wouter H van Megen
- Department of Cardiovascular and Renal Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark
| | - Rebecca Tan
- Department of Physiology, The University of Alberta, Edmonton, Alberta, Canada
| | - Christy H L Lee
- Department of Physiology, The University of Alberta, Edmonton, Alberta, Canada
| | - Per Svenningsen
- Department of Cardiovascular and Renal Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark
| | - R Todd Alexander
- Department of Pediatrics, The University of Alberta, Edmonton, Alberta, Canada.,Membrane Protein Disease Research Group, The University of Alberta, Edmonton, Alberta, Canada
| | - Henrik Dimke
- Department of Cardiovascular and Renal Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark.,Department of Nephrology, Odense University Hospital, Odense, Denmark
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17
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Liu CJ, Cheng CW, Tsai YS, Huang HS. Crosstalk between Renal and Vascular Calcium Signaling: The Link between Nephrolithiasis and Vascular Calcification. Int J Mol Sci 2021; 22:ijms22073590. [PMID: 33808324 PMCID: PMC8036726 DOI: 10.3390/ijms22073590] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2021] [Revised: 03/18/2021] [Accepted: 03/26/2021] [Indexed: 12/11/2022] Open
Abstract
Calcium (Ca2+) is an important mediator of multicellular homeostasis and is involved in several diseases. The interplay among the kidney, bone, intestine, and parathyroid gland in Ca2+ homeostasis is strictly modulated by numerous hormones and signaling pathways. The calcium-sensing receptor (CaSR) is a G protein–coupled receptor, that is expressed in calcitropic tissues such as the parathyroid gland and the kidney, plays a pivotal role in Ca2+ regulation. CaSR is important for renal Ca2+, as a mutation in this receptor leads to hypercalciuria and calcium nephrolithiasis. In addition, CaSR is also widely expressed in the vascular system, including vascular endothelial cells (VECs) and vascular smooth muscle cells (VSMCs) and participates in the process of vascular calcification. Aberrant Ca2+ sensing by the kidney and VSMCs, owing to altered CaSR expression or function, is associated with the formation of nephrolithiasis and vascular calcification. Based on emerging epidemiological evidence, patients with nephrolithiasis have a higher risk of vascular calcification, but the exact mechanism linking the two conditions is unclear. However, a dysregulation in Ca2+ homeostasis and dysfunction in CaSR might be the connection between the two. This review summarizes renal calcium handling and calcium signaling in the vascular system, with a special focus on the link between nephrolithiasis and vascular calcification.
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Affiliation(s)
- Chan-Jung Liu
- Department of Urology, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan 704302, Taiwan; (C.-J.L.); (C.-W.C.)
| | - Chia-Wei Cheng
- Department of Urology, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan 704302, Taiwan; (C.-J.L.); (C.-W.C.)
| | - Yau-Sheng Tsai
- Institute of Clinical Medicine, College of Medicine, National Cheng Kung University, Tainan 704302, Taiwan;
- Center for Clinical Medicine Research, National Cheng Kung University Hospital, Tainan 704302, Taiwan
| | - Ho-Shiang Huang
- Department of Urology, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan 704302, Taiwan; (C.-J.L.); (C.-W.C.)
- Correspondence: ; Tel.: +886-6-2353535 (ext. 5251); Fax: +886-6-2766179
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18
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Oh IH, Jo CH, Kim S, Jo S, Chung S, Kim GH. Thick ascending limb claudins are altered to increase calciuria and magnesiuria in metabolic acidosis. Am J Physiol Renal Physiol 2021; 320:F418-F428. [PMID: 33522409 DOI: 10.1152/ajprenal.00282.2020] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Accepted: 01/21/2021] [Indexed: 12/14/2022] Open
Abstract
Urinary calcium and magnesium wasting is a characteristic feature of metabolic acidosis, and this study focused on the role of the thick ascending limb of Henle's loop in metabolic acidosis-induced hypercalciuria and hypermagnesiuria because thick ascending limb is an important site of paracellular calcium and magnesium reabsorption. Male Sprague-Dawley rats were used to determine the effects of acid loading (by adding NH4Cl, 7.2 mmol/220 g body wt/day to food slurry for 7 days) on renal expression of claudins and then to evaluate whether the results were reversed by antagonizing calcium-sensing receptor (using NPS-2143). At the end of each animal experiment, the kidneys were harvested for immunoblotting, immunofluorescence microscopy, and quantitative PCR (qPCR) analysis of claudins and the calcium-sensing receptor. As expected, NH4Cl loading lowered urinary pH and increased excretion of urinary calcium and magnesium. In NH4Cl-loaded rats, renal protein and mRNA expression of claudin-16, and claudin-19, were decreased compared with controls. However, claudin-14 protein and mRNA increased in NH4Cl-loaded rats. Consistently, the calcium-sensing receptor protein and mRNA were up-regulated in NH4Cl-loaded rats. All these changes were reversed by NPS-2143 coadministration and were confirmed using immunofluorescence microscopy. Hypercalciuria and hypermagnesiuria in NH4Cl-loaded rats were significantly ameliorated by NPS-2143 coadministration as well. We conclude that in metabolic acidosis, claudin-16 and claudin-19 in the thick ascending limb are down-regulated to produce hypercalciuria and hypermagnesiuria via the calcium-sensing receptor.NEW & NOTEWORTHY This study found that the thick ascending limb of Henle's loop is involved in the mechanisms of hypercalciuria and hypermagnesiuria in metabolic acidosis. Specifically, expression of claudin-16/19 and claudin-14 was altered via up-regulation of calcium-sensing receptor in NH4Cl-induced metabolic acidosis. Our novel findings contribute to understanding the regulatory role of paracellular tight junction proteins in the thick ascending limb.
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Affiliation(s)
- Il Hwan Oh
- Department of Internal Medicine, Hanyang University College of Medicine, Seoul, Republic of Korea
| | - Chor Ho Jo
- Institute of Biomedical Science, Hanyang University College of Medicine, Seoul, Republic of Korea
| | - Sua Kim
- Institute of Biomedical Science, Hanyang University College of Medicine, Seoul, Republic of Korea
| | - Sungsin Jo
- Hanyang University Institute for Rheumatology Research, Seoul, Republic of Korea
| | - Sungjin Chung
- Department of Internal Medicine, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Gheun-Ho Kim
- Department of Internal Medicine, Hanyang University College of Medicine, Seoul, Republic of Korea
- Institute of Biomedical Science, Hanyang University College of Medicine, Seoul, Republic of Korea
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