1
|
Yu ASL, Curry JN. Paracellular Transport and Renal Tubule Calcium Handling: Emerging Roles in Kidney Stone Disease. J Am Soc Nephrol 2024:00001751-990000000-00411. [PMID: 39207856 DOI: 10.1681/asn.0000000506] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2024] [Accepted: 08/26/2024] [Indexed: 09/04/2024] Open
Abstract
The kidney plays a major role in maintenance of serum calcium concentration, which must be kept within a narrow range to avoid disruption of numerous physiologic processes that depend critically on the level of extracellular calcium, including cell signaling, bone structure, and muscle and nerve function. This defense of systemic calcium homeostasis comes, however, at the expense of the dumping of calcium into the kidney tissue and urine. Because of the large size and multivalency of the calcium ion, its salts are the least soluble among all the major cations in the body. The potential pathologic consequences of this are nephrocalcinosis and kidney stone disease. In this review, we discuss recent advances that have highlighted critical roles for the proximal tubule and thick ascending limb in renal calcium reabsorption, elucidated the molecular mechanisms for paracellular transport in these segments, and implicated disturbances in these processes in human disease.
Collapse
Affiliation(s)
- Alan S L Yu
- Division of Nephrology and Hypertension, Department of Internal Medicine, Jared Grantham Kidney Institute, University of Kansas Medical Center, Kansas City, Kansas
| | - Joshua N Curry
- Division of Nephrology, Oregon Health Sciences University, Portland, Oregon
| |
Collapse
|
2
|
Apostolova D, Apostolov G, Moten D, Batsalova T, Dzhambazov B. Claudin-12: guardian of the tissue barrier or friend of tumor cells. Tissue Barriers 2024:2387408. [PMID: 39087432 DOI: 10.1080/21688370.2024.2387408] [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: 05/04/2024] [Revised: 07/28/2024] [Accepted: 07/28/2024] [Indexed: 08/02/2024] Open
Abstract
Tight junctions (TJs) are an important component of cellular connectivity. Claudin family proteins, as a constituent of TJs, determine their barrier properties, cell polarity and paracellular permeability. Claudin-12 is an atypical member of the claudin family, as it belongs to the group of non-classical claudins that lack a PDZ-binding domain. It has been shown that claudin-12 is involved in paracellular Ca2+ transients and it is present in normal and hyperplastic tissues in addition to neoplastic tissues. Dysregulation of claudin-12 expression has been reported in various cancers, suggesting that this protein may play an important role in cancer cell migration, invasion, and metastasis. Some studies have shown that claudin-12 gene functions as a tumor suppressor, but others have reported that overexpression of claudin-12 significantly increases the metastatic properties of various tumor cells. Investigating this dual role of claudin-12 is of utmost importance and should therefore be studied in detail. The aim of this review is to provide an overview of the information available to date on claudin-12, including its structure, expression in various tissues and substances that may affect it, with a final focus on its role in cancer.
Collapse
Affiliation(s)
- Desislava Apostolova
- Department of Developmental Biology, Faculty of Biology, Paisii Hilendarski University of Plovdiv, Plovdiv, Bulgaria
| | - Georgi Apostolov
- Department of Neurosurgery, Faculty of Medicine, Medical University of Plovdiv, Plovdiv, Bulgaria
| | - Dzhemal Moten
- Department of Developmental Biology, Faculty of Biology, Paisii Hilendarski University of Plovdiv, Plovdiv, Bulgaria
| | - Tsvetelina Batsalova
- Department of Developmental Biology, Faculty of Biology, Paisii Hilendarski University of Plovdiv, Plovdiv, Bulgaria
| | - Balik Dzhambazov
- Department of Developmental Biology, Faculty of Biology, Paisii Hilendarski University of Plovdiv, Plovdiv, Bulgaria
| |
Collapse
|
3
|
Jiang M, Wang X, Chen Z, Wang X, An Y, Ding L, Xu M, Fan B, Jiao P, Wang C, Wang M, Sun H, Zhao S, Gong Y. Lipolysis-Stimulated Lipoprotein Receptor in Proximal Tubule, BMP-SMAD Signaling, and Kidney Disease. J Am Soc Nephrol 2024; 35:1016-1033. [PMID: 38809616 PMCID: PMC11377808 DOI: 10.1681/asn.0000000000000382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2023] [Accepted: 05/14/2024] [Indexed: 05/31/2024] Open
Abstract
Key Points
We identify that lipolysis-stimulated lipoprotein receptor is highly enriched in the nucleus of mouse and human kidney.This study provides new insights into the role of lipolysis-stimulated lipoprotein receptor in kidney disease.
Background
Lipolysis-stimulated lipoprotein receptor (LSR) is a single-pass membrane protein that plays essential roles in tricellular tight junction organization in the epithelium and endothelium, but its function in kidney physiology and disease development remains unknown.
Methods
Conditional Lsr deletion mice were generated and analyzed to investigate the function of LSR in proximal tubule. Unilateral ischemia-reperfusion was used as an injury model to investigate the role of LSR in AKI and the progression to CKD. Detailed mechanistic analyses were conducted using whole-transcriptome RNA sequencing, immunofluorescence, dual-luciferase reporter gene assay, coimmunoprecipitation, RNA immunoprecipitation, and adeno-associated virus-mediated gene overexpression and knockdown.
Results
The nuclear localization of LSR was found in the kidney. Proximal tubule–specific Lsr knockout mice exhibited alleviated kidney damage and fibrosis compared with those in wild-type mice in response unilateral ischemia-reperfusion injury. Loss of LSR resulted in downregulation of Chrdl1 and activation of bone morphogenetic protein (BMP)-mothers against decapentaplegic homolog (SMAD) signaling in proximal tubules. Treatment with CHRDL1 counteracted the protective effect of LSR deletion in the unilaterally ischemic injured kidney. In addition, the systemic delivery of Chrdl1 short hairpin RNA attenuated injury-induced kidney fibrosis. LSR formed a complex with 14-3-3θ in the nucleus of proximal tubular cells, thereby reducing the interaction between human antigen R and 14-3-3θ, consequently leading to the translocation of unbound human antigen R to the cytoplasm. The absence of LSR promoted the association of 14-3-3θ with human antigen R, potentially resulting in decreased human antigen R levels in the cytoplasm. Reduced human antigen R levels impaired Chrdl1 mRNA stability, subsequently leading to the activation of BMP-SMAD signaling.
Conclusions
Deletion of LSR in proximal tubule deregulated Chrdl1 to activate BMP-SMAD signaling and ameliorated kidney disease.
Collapse
Affiliation(s)
- Min Jiang
- Shandong Engineering Research Center of Molecular Medicine for Renal Diseases, Yantai, China
- Department of Pharmacology, Binzhou Medical University, Yantai, China
| | - Xiangdong Wang
- Department of Physiology, Binzhou Medical University, Yantai, China
| | - Zhenni Chen
- Department of Physiology, Binzhou Medical University, Yantai, China
| | - Xin Wang
- Department of Physiology, Binzhou Medical University, Yantai, China
| | - Yanan An
- Shandong Engineering Research Center of Molecular Medicine for Renal Diseases, Yantai, China
- Department of Physiology, Binzhou Medical University, Yantai, China
| | - Lixia Ding
- Department of Physiology, Binzhou Medical University, Yantai, China
| | - Mengyuan Xu
- Department of Physiology, Binzhou Medical University, Yantai, China
| | - Baozhen Fan
- Department of Urology, Binzhou Medical University Hospital, Binzhou, China
| | - Peng Jiao
- Department of Urology, Binzhou Medical University Hospital, Binzhou, China
| | - Chao Wang
- Department of Urology, The Second Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Mingxia Wang
- Shandong Engineering Research Center of Molecular Medicine for Renal Diseases, Yantai, China
- Department of Physiology, Binzhou Medical University, Yantai, China
| | - Hui Sun
- Shandong Engineering Research Center of Molecular Medicine for Renal Diseases, Yantai, China
- Department of Physiology, Binzhou Medical University, Yantai, China
| | - Shengtian Zhao
- Department of Urology, Binzhou Medical University Hospital, Binzhou, China
- Shandong Provincial Engineering Laboratory of Urologic Tissue Reconstruction, Jinan, China
- Department of Urology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, China
| | - Yongfeng Gong
- Shandong Engineering Research Center of Molecular Medicine for Renal Diseases, Yantai, China
- Department of Physiology, Binzhou Medical University, Yantai, China
| |
Collapse
|
4
|
Staruschenko A, Alexander RT, Caplan MJ, Ilatovskaya DV. Calcium signalling and transport in the kidney. Nat Rev Nephrol 2024; 20:541-555. [PMID: 38641658 DOI: 10.1038/s41581-024-00835-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/27/2024] [Indexed: 04/21/2024]
Abstract
The kidney plays a pivotal role in regulating calcium levels within the body. Approximately 98% of the filtered calcium is reabsorbed in the nephron, and this process is tightly controlled to maintain calcium homeostasis, which is required to facilitate optimal bone mineralization, preserve serum calcium levels within a narrow range, and support intracellular signalling mechanisms. The maintenance of these functions is attributed to a delicate balance achieved by various calcium channels, transporters, and calcium-binding proteins in renal cells. Perturbation of this balance due to deficiency or dysfunction of calcium channels and calcium-binding proteins can lead to severe complications. For example, polycystic kidney disease is linked to aberrant calcium transport and signalling. Furthermore, dysregulation of calcium levels can promote the formation of kidney stones. This Review provides an updated description of the key aspects of calcium handling in the kidney, focusing on the function of various calcium channels and the physiological stimuli that control these channels or are communicated through them. A discussion of the role of calcium as an intracellular second messenger and the pathophysiology of renal calcium dysregulation, as well as a summary of gaps in knowledge and future prospects, are also included.
Collapse
Affiliation(s)
- Alexander Staruschenko
- Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, FL, USA.
- Hypertension and Kidney Research Center, University of South Florida, Tampa, FL, USA.
- James A. Haley Veterans Hospital, Tampa, FL, USA.
| | - R Todd Alexander
- Department of Paediatrics, University of Alberta, Edmonton, AB, Canada
- Women's and Children's Health Institute, Edmonton, AB, Canada
| | - Michael J Caplan
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT, USA
| | - Daria V Ilatovskaya
- Department of Physiology, Medical College of Georgia, Augusta University, Augusta, GA, USA
| |
Collapse
|
5
|
Tan RSG, Lee CHL, Pan W, Wohlgemuth S, Doschak MR, Alexander RT. Disruption of the c-terminal serine protease domain of Fam111a does not alter calcium homeostasis in mice. Physiol Rep 2024; 12:e15977. [PMID: 38697929 PMCID: PMC11065693 DOI: 10.14814/phy2.15977] [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: 12/31/2023] [Revised: 02/28/2024] [Accepted: 03/01/2024] [Indexed: 05/05/2024] Open
Abstract
FAM111A gene mutations cause Kenney-Caffey syndrome (KCS) and Osteocraniostenosis (OCS), conditions characterized by short stature, low serum ionized calcium (Ca2+), low parathyroid hormone (PTH), and bony abnormalities. The molecular mechanism mediating this phenotype is unknown. The c-terminal domain of FAM111A harbors all the known disease-causing variations and encodes a domain with high homology to serine proteases. However, whether this serine protease domain contributes to the maintenance of Ca2+ homeostasis is not known. We hypothesized the disruption of the serine protease domain of FAM111A would disrupt Ca2+ homeostasis. To test this hypothesis, we generated with CRISPR/Cas9, mice with a frameshift insertion (c.1450insA) or large deletion (c.1253-1464del) mutation in the Fam111a serine protease domain. Serum-ionized Ca2+ and PTH levels were not significantly different between wild type, heterozygous, or homozygous Fam111a mutant mice. Additionally, there were no significant differences in fecal or urine Ca2+ excretion, intestinal Ca2+ absorption or overall Ca2+ balance. Only female homozygous (c.1450insA), but not heterozygous mice displayed differences in bone microarchitecture and mineral density compared to wild-type animals. We conclude that frameshift mutations that disrupt the c-terminal serine protease domain do not induce a KCS or OCS phenotype in mice nor alter Ca2+ homeostasis.
Collapse
Affiliation(s)
- Rebecca Siu Ga Tan
- Department of PhysiologyUniversity of AlbertaEdmontonAlbertaCanada
- Membrane Protein Disease Research GroupUniversity of AlbertaEdmontonAlbertaCanada
- The Women and Children's Health Research InstituteEdmontonAlbertaCanada
| | - Christy Hui Lin Lee
- Department of PhysiologyUniversity of AlbertaEdmontonAlbertaCanada
- Membrane Protein Disease Research GroupUniversity of AlbertaEdmontonAlbertaCanada
- The Women and Children's Health Research InstituteEdmontonAlbertaCanada
| | - Wanling Pan
- Department of PhysiologyUniversity of AlbertaEdmontonAlbertaCanada
- Membrane Protein Disease Research GroupUniversity of AlbertaEdmontonAlbertaCanada
| | | | - Michael R. Doschak
- Faculty of Pharmacy & Pharmaceutical SciencesUniversity of AlbertaEdmontonAlbertaCanada
| | - R. Todd Alexander
- Department of PhysiologyUniversity of AlbertaEdmontonAlbertaCanada
- Membrane Protein Disease Research GroupUniversity of AlbertaEdmontonAlbertaCanada
- The Women and Children's Health Research InstituteEdmontonAlbertaCanada
- Department of PediatricsUniversity of AlbertaEdmontonAlbertaCanada
| |
Collapse
|
6
|
Hakimi S, Dutta P, Layton AT. Coupling of renal sodium and calcium transport: a modeling analysis of transporter inhibition and sex differences. Am J Physiol Renal Physiol 2023; 325:F536-F551. [PMID: 37615047 DOI: 10.1152/ajprenal.00145.2023] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Revised: 08/17/2023] [Accepted: 08/17/2023] [Indexed: 08/25/2023] Open
Abstract
Ca2+ transport along the nephron occurs via specific transcellular and paracellular pathways and is coupled to the transport of other electrolytes. Notably, Na+ transport establishes an electrochemical gradient to drive Ca2+ reabsorption. Hence, alterations in renal Na+ handling, under pathophysiological conditions or pharmacological manipulations, can have major effects on Ca2+ transport. An important class of pharmacological agent is diuretics, which are commonly prescribed for the management of blood pressure and fluid balance. The pharmacological targets of diuretics generally directly facilitate Na+ transport but also indirectly affect renal Ca2+ handling. To better understand the underlying mechanisms, we developed a computational model of electrolyte transport along the superficial nephron in the kidney of a male and female rat. Sex differences in renal Ca2+ handling are represented. Model simulations predicted in the female rat nephron lower Ca2+ reabsorption in the proximal tubule and thick ascending limb, but higher reabsorption in the late distal convoluted tubule and connecting tubule, compared with the male nephron. The male rat kidney model yielded a higher urinary Ca2+ excretion than the female model, consistent with animal experiments. Model results indicated that along the proximal tubule and thick ascending limb, Ca2+ and Na+ transport occurred in parallel, but those processes were dissociated in the distal convoluted tubule. Additionally, we conducted simulations of inhibition of channels and transporters that play a major role in Na+ and Ca2+ transport. Simulation results revealed alterations in transepithelial Ca2+ transport, with differential effects among nephron segments and between the sexes.NEW & NOTEWORTHY The kidney plays an important role in the maintenance of whole body Ca2+ balance by regulating Ca2+ reabsorption and excretion. This computational modeling study provides insights into how Ca2+ transport along the nephron is coupled to Na+. Model results indicated that along the proximal tubule and thick ascending limb, Ca2+ and Na+ transport occur in parallel, but those processes were dissociated in the distal convoluted tubule. Simulations also revealed sex-specific responses to different pharmacological manipulations.
Collapse
Affiliation(s)
- Shervin Hakimi
- Department of Applied Mathematics, University of Waterloo, Waterloo, Ontario, Canada
| | - Pritha Dutta
- Department of Applied Mathematics, University of Waterloo, Waterloo, Ontario, Canada
| | - Anita T Layton
- Department of Applied Mathematics, University of Waterloo, Waterloo, Ontario, Canada
- Department of Biology, Cheriton School of Computer Science, and School of Pharmacology, University of Waterloo, Waterloo, Ontario, Canada
| |
Collapse
|
7
|
MacDonald T, Beggs MR, O'Neill D, Kozuka K, Dimke H, Alexander RT. Increased Slc34a2 expression and paracellular phosphate permeability contribute to high intestinal phosphate absorption in young mice. Acta Physiol (Oxf) 2023; 239:e14029. [PMID: 37563989 DOI: 10.1111/apha.14029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Revised: 07/26/2023] [Accepted: 07/27/2023] [Indexed: 08/12/2023]
Abstract
AIM Phosphorus is a critical constituent of bone as a component of hydroxyapatite. Bone mineral content accrues rapidly early in life necessitating a positive phosphorus balance, which could be established by a combination of increased renal reabsorption and intestinal absorption. Intestinal absorption can occur via a transcellular pathway mediated by the apical sodium-phosphate cotransporter, Slc34a2/NaPiIIb or via the paracellular pathway. We sought to determine how young mammals increase dietary phosphorus absorption from the small intestine to establish a positive phosphorus balance, a prerequisite for rapid bone growth. METHODS The developmental expression profile of genes mediating phosphate absorption from the small intestine was determined in mice by qPCR and immunohistochemistry. Additionally, Ussing chamber studies were performed on small bowel of young (p7-p14) and older (8- to 17-week-old) mice to examine developmental changes in paracellular Pi permeability and transcellular Pi transport. RESULTS Blood and urinary Pi levels were higher in young mice. Intestinal paracellular phosphate permeability of young mice was significantly increased relative to older mice across all intestinal segments. NaPiIIb expression was markedly increased in juvenile mice, in comparison to adult animals. Consistent with this, young mice had increased transcellular phosphate flux across the jejunum and ileum relative to older animals. Moreover, transcellular phosphate transport was attenuated by the NaPiIIb inhibitor NTX1942 in the jejunum and ileum of young mice. CONCLUSION Our results are consistent with young mice increasing phosphate absorption via increasing paracellular permeability and the NaPiIIb-mediated transcellular pathway.
Collapse
Affiliation(s)
- Tate MacDonald
- Department of Physiology, The University of Alberta, Edmonton, Alberta, Canada
- The Women and Children's Health Research Institute, Edmonton, Alberta, Canada
| | - Megan R Beggs
- Department of Physiology, The University of Alberta, Edmonton, Alberta, Canada
- The Women and Children's Health Research Institute, Edmonton, Alberta, Canada
| | - Debbie O'Neill
- Department of Physiology, 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
| | - R Todd Alexander
- Department of Physiology, The University of Alberta, Edmonton, Alberta, Canada
- The Women and Children's Health Research Institute, Edmonton, Alberta, Canada
- Department of Pediatrics, The University of Alberta, Edmonton, Alberta, Canada
| |
Collapse
|
8
|
Abstract
Sequential expression of claudins, a family of tight junction proteins, along the nephron mirrors the sequential expression of ion channels and transporters. Only by the interplay of transcellular and paracellular transport can the kidney efficiently maintain electrolyte and water homeostasis in an organism. Although channel and transporter defects have long been known to perturb homeostasis, the contribution of individual tight junction proteins has been less clear. Over the past two decades, the regulation and dysregulation of claudins have been intensively studied in the gastrointestinal tract. Claudin expression patterns have, for instance, been found to be affected in infection and inflammation, or in cancer. In the kidney, a deeper understanding of the causes as well as the effects of claudin expression alterations is only just emerging. Little is known about hormonal control of the paracellular pathway along the nephron, effects of cytokines on renal claudin expression or relevance of changes in paracellular permeability to the outcome in any of the major kidney diseases. By summarizing current findings on the role of specific claudins in maintaining electrolyte and water homeostasis, this Review aims to stimulate investigations on claudins as prognostic markers or as druggable targets in kidney disease.
Collapse
Affiliation(s)
- Luca Meoli
- Clinical Physiology/Nutritional Medicine, Medical Department, Division of Gastroenterology, Infectiology, Rheumatology, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Dorothee Günzel
- Clinical Physiology/Nutritional Medicine, Medical Department, Division of Gastroenterology, Infectiology, Rheumatology, Charité - Universitätsmedizin Berlin, Berlin, Germany.
| |
Collapse
|
9
|
Chen JTC, Hu X, Otto IUC, Schürger C, von Bieberstein BR, Doppler K, Krug SM, Hankir MK, Blasig R, Sommer C, Brack A, Blasig IE, Rittner HL. Myelin barrier breakdown, mechanical hypersensitivity, and painfulness in polyneuropathy with claudin-12 deficiency. Neurobiol Dis 2023; 185:106246. [PMID: 37527762 DOI: 10.1016/j.nbd.2023.106246] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 05/25/2023] [Accepted: 07/28/2023] [Indexed: 08/03/2023] Open
Abstract
BACKGROUND The blood-nerve and myelin barrier shield peripheral neurons and their axons. These barriers are sealed by tight junction proteins, which control the passage of potentially noxious molecules including proinflammatory cytokines via paracellular pathways. Peripheral nerve barrier breakdown occurs in various neuropathies, such as chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) and traumatic neuropathy. Here, we studied the functional role of the tight junction protein claudin-12 in regulating peripheral nerve barrier integrity and CIDP pathogenesis. METHODS Sections from sural nerve biopsies from 23 patients with CIDP and non-inflammatory idiopathic polyneuropathy (PNP) were analyzed for claudin-12 and -19 immunoreactivity. Cldn12-KO mice were generated and subjected to the chronic constriction injury (CCI) model of neuropathy. These mice were then characterized using a battery of barrier and behavioral tests, histology, immunohistochemistry, and mRNA/protein expression. In phenotype rescue experiments, the proinflammatory cytokine TNFα was neutralized with the anti-TNFα antibody etanercept; the peripheral nerve barrier was stabilized with the sonic hedgehog agonist smoothened (SAG). RESULTS Compared to those without pain, patients with painful neuropathy exhibited reduced claudin-12 expression independently of fiber loss. Accordingly, global Cldn12-KO in male mice, but not fertile female mice, selectively caused mechanical allodynia associated with a leaky myelin barrier, increased TNFα, decreased sonic hedgehog (SHH), and loss of small axons accompanied by reduced peripheral myelin protein 22 (Pmp22). Other barriers and neurological functions remained intact. The Cldn12-KO phenotype could be rescued either by neutralizing TNFα with etanercept or stabilizing the barrier with SAG, which both also upregulated the Schwann cell barrier proteins Cldn19 and Pmp22. CONCLUSION These results point to a critical role for claudin-12 in maintaining the myelin barrier presumably via Pmp22 and highlight restoration of the hedgehog pathway as a potential treatment strategy for painful inflammatory neuropathy.
Collapse
Affiliation(s)
- Jeremy Tsung-Chieh Chen
- University Hospital Würzburg, Center for Interdisciplinary Pain Medicine, Department of Anesthesiology, Intensive Care, Emergency and Pain Medicine, 97080 Würzburg, Germany
| | - Xiawei Hu
- University Hospital Würzburg, Center for Interdisciplinary Pain Medicine, Department of Anesthesiology, Intensive Care, Emergency and Pain Medicine, 97080 Würzburg, Germany
| | - Isabel U C Otto
- University Hospital Würzburg, Center for Interdisciplinary Pain Medicine, Department of Anesthesiology, Intensive Care, Emergency and Pain Medicine, 97080 Würzburg, Germany
| | - Christina Schürger
- University Hospital Würzburg, Center for Interdisciplinary Pain Medicine, Department of Anesthesiology, Intensive Care, Emergency and Pain Medicine, 97080 Würzburg, Germany
| | - Bruno Rogalla von Bieberstein
- University Hospital Würzburg, Center for Interdisciplinary Pain Medicine, Department of Anesthesiology, Intensive Care, Emergency and Pain Medicine, 97080 Würzburg, Germany
| | - Kathrin Doppler
- University Hospital Würzburg, Department of Neurology, 97080 Würzburg, Germany
| | - Susanne M Krug
- Charité-Universitätsmedizin Berlin, Clinical Physiology/Nutritional Medicine, 13125 Berlin, Germany
| | - Mohammed K Hankir
- University Hospital Würzburg, Department of General, Transplantation, Visceral, Vascular and Pediatric Surgery, 97080 Würzburg, Germany
| | - Rosel Blasig
- Leibnitz Institute of Molecular Pharmacology, Departments of Molecular Physiology and Cell Biology, 13125 Berlin, Germany
| | - Claudia Sommer
- University Hospital Würzburg, Department of Neurology, 97080 Würzburg, Germany
| | - Alexander Brack
- University Hospital Würzburg, Center for Interdisciplinary Pain Medicine, Department of Anesthesiology, Intensive Care, Emergency and Pain Medicine, 97080 Würzburg, Germany
| | - Ingolf E Blasig
- Leibnitz Institute of Molecular Pharmacology, Departments of Molecular Physiology and Cell Biology, 13125 Berlin, Germany
| | - Heike L Rittner
- University Hospital Würzburg, Center for Interdisciplinary Pain Medicine, Department of Anesthesiology, Intensive Care, Emergency and Pain Medicine, 97080 Würzburg, Germany.
| |
Collapse
|
10
|
Nyimanu D, Behm C, Choudhury S, Yu ASL. The role of claudin-2 in kidney function and dysfunction. Biochem Soc Trans 2023; 51:1437-1445. [PMID: 37387353 DOI: 10.1042/bst20220639] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Revised: 06/19/2023] [Accepted: 06/22/2023] [Indexed: 07/01/2023]
Abstract
Claudin-2 is a tight junction protein expressed in leaky epithelia where it forms paracellular pores permeable to cations and water. The paracellular pore formed by claudin-2 is important in energy-efficient cation and water transport in the proximal tubules of the kidneys. Mounting evidence now suggests that claudin-2 may modulate cellular processes often altered in disease, including cellular proliferation. Also, dysregulation of claudin-2 expression has been linked to various diseases, including kidney stone disease and renal cell carcinoma. However, the mechanisms linking altered claudin-2 expression and function to disease are poorly understood and require further investigation. The aim of this review is to discuss the current understanding of the role of claudin-2 in kidney function and dysfunction. We provide a general overview of the claudins and their organization in the tight junction, the expression, and function of claudin-2 in the kidney, and the evolving evidence for its role in kidney disease.
Collapse
Affiliation(s)
- Duuamene Nyimanu
- The Jared Grantham Kidney Institute, University of Kansas Medical Center, 3901 Rainbow Blvd, Kansas City, KS 66160, U.S.A
| | - Christine Behm
- The Jared Grantham Kidney Institute, University of Kansas Medical Center, 3901 Rainbow Blvd, Kansas City, KS 66160, U.S.A
| | - Sonali Choudhury
- The Jared Grantham Kidney Institute, University of Kansas Medical Center, 3901 Rainbow Blvd, Kansas City, KS 66160, U.S.A
| | - Alan S L Yu
- The Jared Grantham Kidney Institute, University of Kansas Medical Center, 3901 Rainbow Blvd, Kansas City, KS 66160, U.S.A
| |
Collapse
|
11
|
Alexander RT. Kidney stones, hypercalciuria, and recent insights into proximal tubule calcium reabsorption. Curr Opin Nephrol Hypertens 2023; 32:359-365. [PMID: 37074688 DOI: 10.1097/mnh.0000000000000892] [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: 04/20/2023]
Abstract
PURPOSE OF REVIEW Most kidney stones are composed of calcium, and the greatest risk factor for kidney stone formation is hypercalciuria. Patients who form kidney stones often have reduced calcium reabsorption from the proximal tubule, and increasing this reabsorption is a goal of some dietary and pharmacological treatment strategies to prevent kidney stone recurrence. However, until recently, little was known about the molecular mechanism that mediates calcium reabsorption from the proximal tubule. This review summarizes newly uncovered key insights and discusses how they may inform the treatment of kidney stone formers. RECENT FINDINGS Studies examining claudin-2 and claudin-12 single and double knockout mice, combined with cell culture models, support complementary independent roles for these tight junction proteins in contributing paracellular calcium permeability to the proximal tubule. Moreover, a family with a coding variation in claudin-2 causing hypercalciuria and kidney stones have been reported, and reanalysis of Genome Wide Association Study (GWAS) data demonstrates an association between noncoding variations in CLDN2 and kidney stone formation. SUMMARY The current work begins to delineate the molecular mechanisms whereby calcium is reabsorbed from the proximal tubule and suggests a role for altered claudin-2 mediated calcium reabsorption in the pathogenesis of hypercalciuria and kidney stone formation.
Collapse
Affiliation(s)
- R Todd Alexander
- Department of Pediatrics
- Department of Physiology, University of Alberta
- The Women's & Children's Health Research Institute, Edmonton, Alberta, Canada
| |
Collapse
|
12
|
Beggs MR, Young K, Plain A, O'Neill DD, Raza A, Flockerzi V, Dimke H, Alexander RT. Maternal Epidermal Growth Factor Promotes Neonatal Claudin-2 Dependent Increases in Small Intestinal Calcium Permeability. FUNCTION 2023; 4:zqad033. [PMID: 37575484 PMCID: PMC10413934 DOI: 10.1093/function/zqad033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2023] [Revised: 06/01/2023] [Accepted: 06/12/2023] [Indexed: 08/15/2023] Open
Abstract
A higher concentration of calcium in breast milk than blood favors paracellular calcium absorption enabling growth during postnatal development. We aimed to determine whether suckling animals have greater intestinal calcium permeability to maximize absorption and to identify the underlying molecular mechanism. We examined intestinal claudin expression at different ages in mice and in human intestinal epithelial (Caco-2) cells in response to hormones or human milk. We also measured intestinal calcium permeability in wildtype, Cldn2 and Cldn12 KO mice and Caco-2 cells in response to hormones or human milk. Bone mineralization in mice was assessed by μCT. Calcium permeability across the jejunum and ileum of mice were 2-fold greater at 2 wk than 2 mo postnatal age. At 2 wk, Cldn2 and Cldn12 expression were greater, but only Cldn2 KO mice had decreased calcium permeability compared to wildtype. This translated to decreased bone volume, cross-sectional thickness, and tissue mineral density of femurs. Weaning from breast milk led to a 50% decrease in Cldn2 expression in the jejunum and ileum. Epidermal growth factor (EGF) in breast milk specifically increased only CLDN2 expression and calcium permeability in Caco-2 cells. These data support intestinal permeability to calcium, conferred by claudin-2, being greater in suckling mice and being driven by EGF in breast milk. Loss of the CLDN2 pathway leads to suboptimal bone mineralization at 2 wk of life. Overall, EGF-mediated control of intestinal claudin-2 expression contributes to maximal intestinal calcium absorption in suckling animals.
Collapse
Affiliation(s)
- Megan R Beggs
- Department of Physiology, University of Alberta, Edmonton, AB T6G 2H7, Canada
- The Women's & Children's Health Research Institute, Edmonton, AB T6G 1C9, Canada
| | - Kennedi Young
- Department of Physiology, University of Alberta, Edmonton, AB T6G 2H7, Canada
| | - Allen Plain
- 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
| | - Ahsan Raza
- Experimentelle und Klinische Pharmakologie und Toxikologie, Saarland University, 66421 Homburg, Germany
| | - Veit Flockerzi
- Experimentelle und Klinische Pharmakologie und Toxikologie, Saarland University, 66421 Homburg, Germany
| | - Henrik Dimke
- Department of Cardiovascular and Renal Research, Institute of Molecular Medicine, University of Southern Denmark, Odense C DK-5000, Demark
- Department of Nephrology, Odense University Hospital, 5000 Odense C, Denmark
| | - R Todd Alexander
- Department of Physiology, University of Alberta, Edmonton, AB T6G 2H7, Canada
- The Women's & Children's Health Research Institute, Edmonton, AB T6G 1C9, Canada
- Department of Pediatrics, University of Alberta, Edmonton, AB T6G 1C9, Canada
| |
Collapse
|
13
|
Xu Z, Yao X, Duan C, Liu H, Xu H. Metabolic changes in kidney stone disease. Front Immunol 2023; 14:1142207. [PMID: 37228601 PMCID: PMC10203412 DOI: 10.3389/fimmu.2023.1142207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Accepted: 03/06/2023] [Indexed: 05/27/2023] Open
Abstract
Kidney stone disease (KSD) is one of the earliest medical diseases known, but the mechanism of its formation and metabolic changes remain unclear. The formation of kidney stones is a extensive and complicated process, which is regulated by metabolic changes in various substances. In this manuscript, we summarized the progress of research on metabolic changes in kidney stone disease and discuss the valuable role of some new potential targets. We reviewed the influence of metabolism of some common substances on stone formation, such as the regulation of oxalate, the release of reactive oxygen species (ROS), macrophage polarization, the levels of hormones, and the alternation of other substances. New insights into changes in substance metabolism changes in kidney stone disease, as well as emerging research techniques, will provide new directions in the treatment of stones. Reviewing the great progress that has been made in this field will help to improve the understanding by urologists, nephrologists, and health care providers of the metabolic changes in kidney stone disease, and contribute to explore new metabolic targets for clinical therapy.
Collapse
Affiliation(s)
- Zhenzhen Xu
- Department of Urology, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Xiangyang Yao
- Department of Urology, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Chen Duan
- Department of Urology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Haoran Liu
- Stanford Bio-X, Stanford University, San Francisco, CA, United States
| | - Hua Xu
- Department of Urology, Zhongnan Hospital of Wuhan University, Wuhan, China
- Department of Biological Repositories, Zhongnan Hospital of Wuhan University, Wuhan, China
- Cancer Precision Diagnosis and Treatment and Translational Medicine Hubei Engineering Research Center, Zhongnan Hospital of Wuhan University, Wuhan, China
| |
Collapse
|
14
|
Houillier P, Lievre L, Hureaux M, Prot-Bertoye C. Mechanisms of paracellular transport of magnesium in intestinal and renal epithelia. Ann N Y Acad Sci 2023; 1521:14-31. [PMID: 36622354 DOI: 10.1111/nyas.14953] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Magnesium is the fourth most abundant cation in the body. It plays a critical role in many biological processes, including the process of energy release. Paracellular transport of magnesium is mandatory for magnesium homeostasis. In addition to intestinal absorption that occurs in part across the paracellular pathway, magnesium is reabsorbed by the kidney tubule. The bulk of magnesium is reabsorbed through the paracellular pathway in the proximal tubule and the thick ascending limb of the loop of Henle. The finding that rare genetic diseases due to pathogenic variants in genes encoding specific claudins (CLDNs), proteins located at the tight junction that determine the selectivity and the permeability of the paracellular pathway, led to an awareness of their importance in magnesium homeostasis. Familial hypomagnesemia with hypercalciuria and nephrocalcinosis is caused by a loss of function of CLDN16 or CLDN19. Pathogenic CLDN10 variants cause HELIX syndrome, which is associated with a severe renal loss of sodium chloride and hypermagnesemia. The present review summarizes the current knowledge of the mechanisms and factors involved in paracellular magnesium permeability. The review also highlights some of the unresolved questions that need to be addressed.
Collapse
Affiliation(s)
- Pascal Houillier
- Centre de Recherche des Cordeliers, INSERM, Sorbonne Université, Université Paris Cité, Paris, France
- CNRS ERL 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
| | - Loïc Lievre
- Centre de Recherche des Cordeliers, INSERM, Sorbonne Université, Université Paris Cité, Paris, France
- CNRS ERL 8228 - Laboratoire de Physiologie Rénale et Tubulopathies, Paris, France
| | - Marguerite Hureaux
- Centre de Référence des Maladies Rénales Héréditaires de l'Enfant et de l'Adulte (MARHEA), Paris, France
- Assistance Publique-Hôpitaux de Paris, Hôpital Européen Georges Pompidou, Service de Génétique, Paris, France
- Paris Centre de Recherche Cardio-vasculaire, INSERM, Université Paris Cité, Paris, France
| | - Caroline Prot-Bertoye
- Centre de Recherche des Cordeliers, INSERM, Sorbonne Université, Université Paris Cité, Paris, France
- CNRS ERL 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
| |
Collapse
|
15
|
Kriuchkova N, Breiderhoff T, Müller D, Yilmaz DE, Demirci H, Drewell H, Günzel D, Himmerkus N, Bleich M, Persson PB, Mutig K. Furosemide rescues hypercalciuria in familial hypomagnesaemia with hypercalciuria and nephrocalcinosis model. Acta Physiol (Oxf) 2023; 237:e13927. [PMID: 36606514 DOI: 10.1111/apha.13927] [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: 06/08/2022] [Revised: 11/10/2022] [Accepted: 01/02/2023] [Indexed: 01/07/2023]
Abstract
AIM Perturbed calcium homeostasis limits life expectancy in familial hypomagnesaemia with hypercalciuria and nephrocalcinosis (FHHNC). This rare disease occurs by loss-of-function mutations in CLDN16 or CLDN19 genes, causing impaired paracellular reabsorption of divalent cations along the cortical thick ascending limb (cTAL). Only partial compensation takes place in the ensuing late distal convoluted tubule, connecting tubule, and collecting duct, where the luminal transient receptor potential channel V5 (TRPV5), as well as basolateral plasma membrane calcium ATPase (PMCA) and sodium-potassium exchanger (NCX1) mediate transcellular Ca2+ reabsorption. The loop diuretic furosemide induces compensatory activation in these distal segments. Normally, furosemide enhances urinary calcium excretion via inhibition of the aforementioned cTAL. As Ca2+ reabsorption in the cTAL is already severely impaired in FHHNC patients, furosemide may alleviate hypercalciuria in this disease by activation of the distal transcellular Ca2+ transport proteins. METHODS Cldn16-deficient mice (Cldn16-/- ) served as a FHHNC model. Wild-type (WT) and Cldn16-/- mice were treated with furosemide (7 days of 40 mg/kg bw) or vehicle. We assessed renal electrolyte handling (metabolic cages) and key divalent transport proteins. RESULTS Cldn16-/- mice show higher Ca2+ excretion than WT and compensatory stimulation of Cldn2, TRPV5, and NCX1 at baseline. Furosemide reduced hypercalciuria in Cldn16-/- mice and enhanced TRPV5 and PMCA levels in Cldn16-/- but not in WT mice. CONCLUSIONS Furosemide significantly reduces hypercalciuria, likely via upregulation of luminal and basolateral Ca2+ transport systems in the distal nephron and collecting duct in this model for FHHNC.
Collapse
Affiliation(s)
- Natalia Kriuchkova
- Department of Translational Physiology, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Tilman Breiderhoff
- Division of Gastroenterology, Nephrology and Metabolic Diseases, Department of Pediatrics, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Dominik Müller
- Division of Gastroenterology, Nephrology and Metabolic Diseases, Department of Pediatrics, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Duygu Elif Yilmaz
- Department of Functional Anatomy, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Hasan Demirci
- Department of Functional Anatomy, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Hoora Drewell
- Department of Translational Physiology, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Dorothee Günzel
- Clinical Physiology/Division of Nutritional Medicine, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | | | - Markus Bleich
- Institute of Physiology, Kiel University, Kiel, Germany
| | - Pontus B Persson
- Department of Translational Physiology, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Kerim Mutig
- Department of Translational Physiology, Charité-Universitätsmedizin Berlin, Berlin, Germany
| |
Collapse
|
16
|
Abstract
Mg2+ is essential for many cellular and physiological processes, including muscle contraction, neuronal activity, and metabolism. Consequently, the blood Mg2+ concentration is tightly regulated by balanced intestinal Mg2+ absorption, renal Mg2+ excretion, and Mg2+ storage in bone and soft tissues. In recent years, the development of novel transgenic animal models and identification of Mendelian disorders has advanced our current insight in the molecular mechanisms of Mg2+ reabsorption in the kidney. In the proximal tubule, Mg2+ reabsorption is dependent on paracellular permeability by claudin-2/12. In the thick ascending limb of Henle's loop, the claudin-16/19 complex provides a cation-selective pore for paracellular Mg2+ reabsorption. The paracellular Mg2+ reabsorption in this segment is regulated by the Ca2+-sensing receptor, parathyroid hormone, and mechanistic target of rapamycin (mTOR) signaling. In the distal convoluted tubule, the fine tuning of Mg2+ reabsorption takes place by transcellular Mg2+ reabsorption via transient receptor potential melastatin-like types 6 and 7 (TRPM6/TRPM7) divalent cation channels. Activity of TRPM6/TRPM7 is dependent on hormonal regulation, metabolic activity, and interacting proteins. Basolateral Mg2+ extrusion is still poorly understood but is probably dependent on the Na+ gradient. Cyclin M2 and SLC41A3 are the main candidates to act as Na+/Mg2+ exchangers. Consequently, disturbances of basolateral Na+/K+ transport indirectly result in impaired renal Mg2+ reabsorption in the distal convoluted tubule. Altogether, this review aims to provide an overview of the molecular mechanisms of Mg2+ reabsorption in the kidney, specifically focusing on transgenic mouse models and human hereditary diseases.
Collapse
Affiliation(s)
- Jeroen H F de Baaij
- Department of Physiology, Radboud University Medical Center, Nijmegen, The Netherlands
| |
Collapse
|
17
|
Wei W, Li W, Yang L, Weeramantry S, Ma L, Fu P, Zhao Y. Tight junctions and acute kidney injury. J Cell Physiol 2023; 238:727-741. [PMID: 36815285 DOI: 10.1002/jcp.30976] [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: 09/01/2022] [Revised: 01/27/2023] [Accepted: 02/04/2023] [Indexed: 02/24/2023]
Abstract
Acute kidney injury (AKI) is characterized by a rapid reduction in kidney function caused by various etiologies. Tubular epithelial cell dysregulation plays a pivotal role in the pathogenesis of AKI. Tight junction (TJ) is the major molecular structure that connects adjacent epithelial cells and is critical in maintaining barrier function and determining the permeability of epithelia. TJ proteins are dysregulated in various types of AKI, and some reno-protective drugs can reverse TJ changes caused by insult. An in-depth understanding of TJ regulation and its causality with AKI will provide more insight to the disease pathogenesis and will shed light on the potential role of TJs to serve as novel therapeutic targets in AKI.
Collapse
Affiliation(s)
- Wei Wei
- Division of Nephrology and Kidney Research Institute, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Weiying Li
- Department of Internal Medicine, Florida Hospital/AdventHealth, Orlando, Florida, USA
| | - Letian Yang
- Division of Nephrology and Kidney Research Institute, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Savidya Weeramantry
- Department of Internal Medicine, West China School of Medicine, Sichuan University, Chengdu, Sichuan, China
| | - Liang Ma
- Division of Nephrology and Kidney Research Institute, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Ping Fu
- Division of Nephrology and Kidney Research Institute, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Yuliang Zhao
- Division of Nephrology and Kidney Research Institute, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| |
Collapse
|
18
|
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.
Collapse
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
| |
Collapse
|
19
|
The importance of kidney calcium handling in the homeostasis of extracellular fluid calcium. Pflugers Arch 2022; 474:885-900. [PMID: 35842482 DOI: 10.1007/s00424-022-02725-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Revised: 06/09/2022] [Accepted: 06/30/2022] [Indexed: 12/13/2022]
Abstract
Extracellular fluid calcium concentration must be maintained within a narrow range in order to sustain many biological functions, encompassing muscle contraction, blood coagulation, and bone and tooth mineralization. Blood calcium value is critically dependent on the ability of the renal tubule to reabsorb the adequate amount of filtered calcium. Tubular calcium reabsorption is carried out by various and complex mechanisms in 3 distinct segments: the proximal tubule, the cortical thick ascending limb of the loop of Henle, and the late distal convoluted/connecting tubule. In addition, calcium reabsorption is tightly controlled by many endocrine, paracrine, and autocrine factors, as well as by non-hormonal factors, in order to adapt the tubular handling of calcium to the metabolic requirements. The present review summarizes the current knowledge of the mechanisms and factors involved in calcium handling by the kidney and, ultimately, in extracellular calcium homeostasis. The review also highlights some of our gaps in understanding that need to be addressed in the future.
Collapse
|
20
|
Beggs MR, Bhullar H, Dimke H, Alexander RT. The contribution of regulated colonic calcium absorption to the maintenance of calcium homeostasis. J Steroid Biochem Mol Biol 2022; 220:106098. [PMID: 35339651 DOI: 10.1016/j.jsbmb.2022.106098] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 03/05/2022] [Accepted: 03/20/2022] [Indexed: 11/20/2022]
Abstract
Calcium absorption and secretion can occur along the length of the small and large intestine. To date, the focus of research into intestinal calcium absorption has been the small intestine, the site contributing the majority of intestinal calcium absorption. However, evidence that the colon contributes as much as 10% of enteral calcium transport has been available for decades. Transcellular calcium absorption and bidirectional paracellular calcium flux contributing to either net absorption or secretion have been observed in the colon, depending on the physiological state. Moreover, the calcium transport pathways contributing to colonic absorption or secretion are regulated by a variety of hormones, including calcitriol, plasma calcium and dietary factors, including prebiotics. Herein we review historical and recent research highlighting the role of colonic calcium transport in overall maintenance of calcium balance, and suggest these data are consistent with the colon being a site of significant regulated transepithelial calcium transport.
Collapse
Affiliation(s)
- Megan R Beggs
- Department of Physiology, University of Alberta, Canada; Women's and Children's Health Institute, 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, Denmark
| | - R Todd Alexander
- Department of Physiology, University of Alberta, Canada; Women's and Children's Health Institute, Alberta, Canada; Department of Paediatrics, University of Alberta, Canada.
| |
Collapse
|
21
|
Molecular mechanisms altering tubular calcium reabsorption. Pediatr Nephrol 2022; 37:707-718. [PMID: 33796889 DOI: 10.1007/s00467-021-05049-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Revised: 02/12/2021] [Accepted: 03/09/2021] [Indexed: 12/09/2022]
Abstract
The majority of calcium filtered by the glomerulus is reabsorbed along the nephron. Most is reabsorbed from the proximal tubule (> 60%) via a paracellular pathway composed of the tight junction proteins claudins-2 and -12, a process driven by sodium and consequently water reabsorption. The thick ascending limb reabsorbs the next greatest amount of calcium (20-25%), also by a paracellular pathway composed of claudins-16 and -19. This pathway is regulated by the CaSR, whose activity increases the expression of claudin-14, a protein that blocks paracellular calcium reabsorption. The fine tuning of urinary calcium excretion occurs in the distal convoluted and connecting tubule by a transcellular pathway composed of the apical calcium channel TRPV5, the calcium shuttling protein calbindin-D28K and the basolateral proteins PMCA1b and the sodium calcium exchanger, NCX. Not surprisingly, mutations in a subset of these genes cause monogenic disorders with hypercalciuria as a part of the phenotype. More commonly, "idiopathic" hypercalciuria is encountered clinically with genetic variations in CLDN14, the CASR and TRPV5 associating with kidney stones and increased urinary calcium excretion. An understanding of the molecular pathways conferring kidney tubular calcium reabsorption is employed in this review to help explain how dietary and medical interventions for this disorder lower urinary calcium excretion.
Collapse
|
22
|
Jo CH, Kim S, Kim GH. Claudins in kidney health and disease. Kidney Res Clin Pract 2022; 41:275-287. [PMID: 35354245 PMCID: PMC9184838 DOI: 10.23876/j.krcp.21.279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Accepted: 12/29/2021] [Indexed: 11/04/2022] Open
Abstract
Claudins are strategically located to exert their physiologic actions along with the nephron segments from the glomerulus. Claudin-1 is normally located in the Bowman’s capsule, but its overexpression can reach the podocytes and lead to albuminuria. In the proximal tubule (PT), claudin-2 forms paracellular channels selective for water, Na+, K+, and Ca2+. Claudin-2 gene mutations are associated with hypercalciuria and kidney stones. Claudin-10 has two splice variants, -10a and -10b; Claudin-10a acts as an anion-selective channel in the PT, and claudin-10b functions as a cation-selective pore in the thick ascending limb (TAL). Claudin-16 and claudin-19 mediate paracellular transport of Na+, Ca2+, and Mg2+ in the TAL, where the expression of claudin-3/16/19 and claudin-10b are mutually exclusive. The claudin-16 or -19 mutation causes familial hypomagnesemia with hypercalciuria and nephrocalcinosis. Claudin-14 polymorphisms have been linked to increased risk of hypercalciuria. Claudin-10b mutations produce HELIX syndrome, which encompasses hypohidrosis, electrolyte imbalance, lacrimal gland dysfunction, ichthyosis, and xerostomia. Hypercalciuria and magnesuria in metabolic acidosis are related to downregulation of PT and TAL claudins. In the TAL, stimulation of calcium-sensing receptors upregulates claudin-14 and negatively acts on the claudin-16/19 complex. Claudin-3 acts as a general barrier to ions in the collecting duct. If this barrier is disturbed, urine acidification might be impaired. Claudin-7 forms a nonselective paracellular channel facilitating Cl– and Na+ reabsorption in the collecting ducts. Claudin-4 and -8 serve as anion channels and mediate paracellular Cl– transport; their upregulation may contribute to pseudohypoaldosteronism II and salt-sensitive hypertension.
Collapse
Affiliation(s)
- Chor ho Jo
- Hanyang Biomedical Research Institute, Hanyang University College of Medicine, Seoul, Republic of Korea
| | - Sua Kim
- Hanyang Biomedical Research Institute, Hanyang University College of Medicine, Seoul, Republic of Korea
| | - Gheun-Ho Kim
- Hanyang Biomedical Research Institute, Hanyang University College of Medicine, Seoul, Republic of Korea
- Department of Internal Medicine, Hanyang University College of Medicine, Seoul, Republic of Korea
- Correspondence: Gheun-Ho Kim Department of Internal Medicine, Hanyang University College of Medicine, 222-1 Wangsimni-ro, Seongdong-gu, Seoul 04763, Republic of Korea. E-mail:
| |
Collapse
|
23
|
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.
Collapse
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
| |
Collapse
|
24
|
Babio L, Lokman PM, Damsteegt EL, Dutoit L. Are Cell Junctions Implicated in the Regulation of Vitellogenin Uptake? Insights from an RNAseq-Based Study in Eel, Anguilla australis. Cells 2022; 11:550. [PMID: 35159359 PMCID: PMC8834532 DOI: 10.3390/cells11030550] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Revised: 01/31/2022] [Accepted: 02/02/2022] [Indexed: 02/04/2023] Open
Abstract
At the onset of puberty, ovarian follicles become competent to incorporate large amounts of vitellogenin (Vtg). Using an RNAseq-based approach, transcriptomes from pre-vitellogenic (PV) and early vitellogenic (EV) ovaries from wild-caught eel, Anguilla australis, were compared to investigate the expression of specific genes encoding cell junction proteins that could be involved in regulating Vtg uptake. Partial support was found for the mechanical barrier hypothesis proposing that the access of Vtg to the oolemma is restricted by a tight junction (TJ) network within the granulosa cell layer, which changes between the PV and EV stage. Among 25 genes encoding TJ-constituting proteins, five were down-regulated and two were up-regulated. A chemical barrier hypothesis stating that gap junctions (GJs) are involved in modulating Vtg uptake was not supported, as only five GJs were found to be expressed in the ovary with no significant changes in expression between stages. Furthermore, the endocytic pathway was found to be up-regulated during the PV-EV transition. Finally, the study showed that gene expression patterns may help identify suitable candidates involved in the regulation of Vtg uptake, and provided novel sequence data for A. australis, including putative Vtg receptors corresponding to Lr8 and Lrp13 members of the low-density lipoprotein receptor family.
Collapse
Affiliation(s)
- Lucila Babio
- Department of Zoology, University of Otago, 340 Great King Street, P.O. Box 56, Dunedin 9054, New Zealand; (P.M.L.); (E.L.D.); (L.D.)
| | | | | | | |
Collapse
|
25
|
Negri AL, Del Valle EE. Role of claudins in idiopathic hypercalciuria and renal lithiasis. Int Urol Nephrol 2022; 54:2197-2204. [PMID: 35084652 DOI: 10.1007/s11255-022-03119-2] [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: 07/14/2021] [Accepted: 01/11/2022] [Indexed: 11/25/2022]
Abstract
Paracellular transport in the kidney is mediated by a family of proteins located in the tight junctions called claudins which confers its ionic selectivity. Claudin-2 is highly expressed in the proximal tubule and descending limb of Henle and mediate paracellular reabsorption of sodium and calcium cations. In the thick ascending limb of Henle (TALH) calcium is reabsorbed by a paracellular channel formed by Claudin-16 and-19. Claudin-16 mediates cationic permeability while Claudin-19 increases the cationic selectivity of Claudin-16 by blocking anionic permeability. On the other hand, Claudin 14, that is also located in TALH, inhibits the paracellular permeability of Claudin-16 to calcium. Recent wide genomic association analysis studies have detected four common synonymous variants (genetic polymorphisms of a single nucleotide, SNPs) at the locus of Claudin-14 gene that were significantly associated with the presence of renal lithiasis. Another study of wide genomic association and nephrolithiasis was carried out in the general population but including chromosome X, where claudin-2 gene is located. They detected nine SNPs that had a significant association with renal lithiasis risk. A greater knowledge of the paracellular pathway controlled by claudins and its regulation will allow us to develop future new treatments for idiopathic hypercalciuria and renal lithiasis.
Collapse
Affiliation(s)
- Armando Luis Negri
- Institute for Metabolic Research, Faculty of Medicine, Del Salvador University, Libertad 836, 1 Floor, 1012, Buenos Aires, Argentina.
| | - Elisa Elena Del Valle
- Institute for Metabolic Research, Faculty of Medicine, Del Salvador University, Libertad 836, 1 Floor, 1012, Buenos Aires, Argentina
| |
Collapse
|
26
|
Breiderhoff T, Himmerkus N, Meoli L, Fromm A, Sewerin S, Kriuchkova N, Nagel O, Ladilov Y, Krug S, Quintanova C, Stumpp M, Garbe-Schönberg D, Westernströer U, Merkel C, Brinkhus M, Altmüller J, Schweiger M, Mueller D, Mutig K, Morawski M, Halbritter J, Milatz S, Bleich M, Günzel D. Claudin-10a Deficiency Shifts Proximal Tubular Cl - Permeability to Cation Selectivity via Claudin-2 Redistribution. J Am Soc Nephrol 2022; 33:699-717. [PMID: 35031570 PMCID: PMC8970455 DOI: 10.1681/asn.2021030286] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Accepted: 12/20/2021] [Indexed: 11/03/2022] Open
Abstract
Background The tight junction proteins claudin-2 and claudin-10a form paracellular cation and anion channels, respectively, and are expressed in the proximal tubule. However, the physiological role of claudin-10a in the kidney has been unclear. Methods To investigate the physiologic role of claudin-10a, we generated claudin-10a-deficient mice; confirmed successful knockout by Southern blot, Western blot, and immunofluorescence staining; and analyzed urine and serum of knockout and wild-type animals. We also used electrophysiologic studies to investigate the functionality of isolated proximal tubules, and studied compensatory regulation by pharmacologic intervention, RNA sequencing analysis, Western blot, immunofluorescence staining, and respirometry. Results Mice deficient in claudin-10a were fertile and without overt phenotypes. Upon knockout, claudin-10a was replaced by claudin-2 in all proximal tubule segments. Electrophysiology showed conversion from paracellular anion preference to cation preference and a loss of paracellular Cl- over HCO3- preference. As a consequence, there was tubular retention of calcium and magnesium, higher urine pH, and mild hypermagnesemia. A comparison of other urine and serum parameters under control conditions and sequential pharmacologic transport inhibition, as well as unchanged fractional lithium excretion, suggested compensative measures in proximal and distal tubular segments. Changes in proximal tubular oxygen handling and differential expression of genes regulating fatty acid metabolism indicated proximal tubular adaptation. Western blot and immunofluorescence revealed alterations in distal tubular transport. Conclusions Claudin-10a is the major paracellular anion channel in the proximal tubule and its deletion causes calcium and magnesium hyperreabsorption by claudin-2 redistribution. Transcellular transport in proximal and distal segments and proximal tubular metabolic adaptation compensate for loss of paracellular anion permeability.
Collapse
Affiliation(s)
- Tilman Breiderhoff
- T Breiderhoff, Department of Pediatrics, Division of Gastroenterology, Nephrology and Metabolic Medicine, Charite Universitatsmedizin Berlin, Berlin, Germany
| | - Nina Himmerkus
- N Himmerkus, Institute of Physiology, Christian-Albrechts-Universität zu Kiel, Kiel, Germany
| | - Luca Meoli
- L Meoli, Clinical Physiology / Div. of Nutritional Medicine, Charité Universitätsmedizin Berlin, Berlin, Germany
| | - Anja Fromm
- A Fromm, Clinical Physiology / Div. of Nutritional Medicine, Charité Universitätsmedizin Berlin, Berlin, Germany
| | - Sebastian Sewerin
- S Sewerin, Division of Nephrology, University of Leipzig Medical Center, Leipzig, Germany
| | - Natalia Kriuchkova
- N Kriuchkova, Institute for Functional Anatomy, Charité Universitätsmedizin Berlin, Berlin, Germany
| | - Oliver Nagel
- O Nagel, Clinical Physiology / Div. of Nutritional Medicine, Charité Universitätsmedizin Berlin, Berlin, Germany
| | - Yury Ladilov
- Y Ladilov, Clinical Physiology / Div. of Nutritional Medicine, Charité Universitätsmedizin Berlin, Berlin, Germany
| | - Susanne Krug
- S Krug, Clinical Physiology / Div. of Nutritional Medicine, Charité Universitätsmedizin Berlin, Berlin, Germany
| | - Catarina Quintanova
- C Quintanova, Institute of Physiology, Christian-Albrechts-Universitat zu Kiel, Kiel, Germany
| | - Meike Stumpp
- M Stumpp, Zoological Institute, Comparative Immunobiology, Christian-Albrechts-Universität zu Kiel, Kiel, Germany
| | - Dieter Garbe-Schönberg
- D Garbe-Schönberg, Institute of Geosciences, Christian-Albrechts-Universität zu Kiel, Kiel, Germany
| | - Ulrike Westernströer
- U Westernströer, Institute of Geosciences, Christian-Albrechts-Universität zu Kiel, Kiel, Germany
| | - Cosima Merkel
- C Merkel, Institute of Physiology, Christian-Albrechts-Universität zu Kiel, Kiel, Germany
| | - Merle Brinkhus
- M Brinkhus, Institute of Physiology, Christian-Albrechts-Universität zu Kiel, Kiel, Germany
| | - Janine Altmüller
- J Altmüller, Cologne Center for Genomics, University of Cologne, Koln, Germany
| | - Michal Schweiger
- M Schweiger, Cologne Center for Genomics, University of Cologne, Koln, Germany
| | - Dominik Mueller
- D Mueller, Department of Pediatrics, Division of Gastroenterology, Nephrology and Metabolic Medicine, Charité Universitätsmedizin Berlin, Berlin, Germany
| | - Kerim Mutig
- K Mutig, Institute for Functional Anatomy, Charité Universitätsmedizin Berlin, Berlin, Germany
| | - Markus Morawski
- M Morawski, Leipzig University Paul Flechsig Institute of Brain Research, Leipzig, Germany
| | - Jan Halbritter
- J Halbritter, Division of Nephrology, University of Leipzig Medical Center, Leipzig, Germany
| | - Susanne Milatz
- S Milatz, Institute of Physiology, Christian-Albrechts-Universität zu Kiel, Kiel, Germany
| | - Markus Bleich
- M Bleich, Institute of Physiology, Christian-Albrechts-Universität zu Kiel, Kiel, Germany
| | - Dorothee Günzel
- D Günzel, Clinical Physiology / Div. of Nutritional Medicine, Christian-Albrechts-Universität zu Kiel, Kiel, Germany
| |
Collapse
|
27
|
Xing W, Pourteymoor S, Chen Y, Mohan S. Targeted Deletion of the Claudin12 Gene in Mice Increases Articular Cartilage and Inhibits Chondrocyte Differentiation. Front Endocrinol (Lausanne) 2022; 13:931318. [PMID: 35937800 PMCID: PMC9354527 DOI: 10.3389/fendo.2022.931318] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Accepted: 06/22/2022] [Indexed: 11/27/2022] Open
Abstract
To study the role of Claudin (CLDN)12 in bone, we developed mice with a targeted deletion of exon2 in the Cldn12 gene for skeletal phenotype analysis. Micro-CT analysis of the secondary spongiosa of distal femurs of mice with targeted disruption of the Cldn12 gene and control littermates showed no significant genotype-specific differences in either cortical or trabecular bone parameters for either gender in 13-week-old mice. Immunohistochemistry revealed that while CLDN12 was expressed in both differentiating chondrocytes and osteoblasts of the secondary spongiosa of 3-week-old wild-type mice, its expression was restricted to differentiating chondrocytes in the articular cartilage and growth plate in adult mice. Articular cartilage area at the knee were increased by 47% in Cldn12 knockout (KO) mice compared to control littermates. Micro-CT analyses found that while the trabecular number was increased by 9% and the trabecular spacing was reduced by 9% in the femoral epiphysis of Cldn12 KO mice, neither bone volume nor bone volume adjusted for tissue volume was different between the two genotypes. The expression levels of Clusterin, Lubricin and Mmp13 were increased by 56%, 46%, and 129%, respectively, in primary articular chondrocytes derived from KO compared to control mice. Our data indicate that targeted deletion of the Cldn12 gene in mice increases articular cartilage, in part, by promoting articular chondrocyte phenotype.
Collapse
Affiliation(s)
- Weirong Xing
- Musculoskeletal Disease Center, VA Loma Linda Healthcare Systems, Loma Linda, CA, United States
- Department of Medicine, Loma Linda University, Loma Linda, CA, United States
| | - Sheila Pourteymoor
- Musculoskeletal Disease Center, VA Loma Linda Healthcare Systems, Loma Linda, CA, United States
| | - Yian Chen
- Musculoskeletal Disease Center, VA Loma Linda Healthcare Systems, Loma Linda, CA, United States
| | - Subburaman Mohan
- Musculoskeletal Disease Center, VA Loma Linda Healthcare Systems, Loma Linda, CA, United States
- Department of Medicine, Loma Linda University, Loma Linda, CA, United States
- Department of Biochemistry, Loma Linda University, Loma Linda, CA, United States
- Department of Orthopedic Surgery, Loma Linda University, Loma Linda, CA, United States
- *Correspondence: Subburaman Mohan,
| |
Collapse
|
28
|
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.
Collapse
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
| |
Collapse
|
29
|
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.
Collapse
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
| |
Collapse
|
30
|
Bedogni F, Hevner RF. Cell-Type-Specific Gene Expression in Developing Mouse Neocortex: Intermediate Progenitors Implicated in Axon Development. Front Mol Neurosci 2021; 14:686034. [PMID: 34321999 PMCID: PMC8313239 DOI: 10.3389/fnmol.2021.686034] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Accepted: 06/03/2021] [Indexed: 01/06/2023] Open
Abstract
Cerebral cortex projection neurons (PNs) are generated from intermediate progenitors (IPs), which are in turn derived from radial glial progenitors (RGPs). To investigate developmental processes in IPs, we profiled IP transcriptomes in embryonic mouse neocortex, using transgenic Tbr2-GFP mice, cell sorting, and microarrays. These data were used in combination with in situ hybridization to ascertain gene sets specific for IPs, RGPs, PNs, interneurons, and other neural and non-neural cell types. RGP-selective transcripts (n = 419) included molecules for Notch receptor signaling, proliferation, neural stem cell identity, apical junctions, necroptosis, hippo pathway, and NF-κB pathway. RGPs also expressed specific genes for critical interactions with meningeal and vascular cells. In contrast, IP-selective genes (n = 136) encoded molecules for activated Delta ligand presentation, epithelial-mesenchymal transition, core planar cell polarity (PCP), axon genesis, and intrinsic excitability. Interestingly, IPs expressed several “dependence receptors” (Unc5d, Dcc, Ntrk3, and Epha4) that induce apoptosis in the absence of ligand, suggesting a competitive mechanism for IPs and new PNs to detect key environmental cues or die. Overall, our results imply a novel role for IPs in the patterning of neuronal polarization, axon differentiation, and intrinsic excitability prior to mitosis. Significantly, IPs highly express Wnt-PCP, netrin, and semaphorin pathway molecules known to regulate axon polarization in other systems. In sum, IPs not only amplify neurogenesis quantitatively, but also molecularly “prime” new PNs for axogenesis, guidance, and excitability.
Collapse
Affiliation(s)
| | - Robert F Hevner
- Department of Pathology, University of California, San Diego, La Jolla, CA, United States
| |
Collapse
|
31
|
Reduced Claudin-12 Expression Predicts Poor Prognosis in Cervical Cancer. Int J Mol Sci 2021; 22:ijms22073774. [PMID: 33917356 PMCID: PMC8038723 DOI: 10.3390/ijms22073774] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2021] [Revised: 04/01/2021] [Accepted: 04/03/2021] [Indexed: 01/03/2023] Open
Abstract
Background: Within the claudin (CLDN) family, CLDN12 mRNA expression is altered in various types of cancer, but its clinicopathological relevance has yet to be established due to the absence of specific antibodies (Abs) with broad applications. Methods: We generated a monoclonal Ab (mAb) against human/mouse CLDN12 and verified its specificity. By performing immunohistochemical staining and semiquantification, we evaluated the relationship between CLDN12 expression and clinicopathological parameters in tissues from 138 cases of cervical cancer. Results: Western blot and immunohistochemical analyses revealed that the established mAb selectively recognized the CLDN12 protein. Twenty six of the 138 cases (18.8%) showed low CLDN12 expression, and the disease-specific survival (DSS) and recurrence-free survival rates were significantly decreased compared with those in the high CLDN12 expression group. We also demonstrated, via univariable and multivariable analyses, that the low CLDN12 expression represents a significant prognostic factor for the DSS of cervical cancer patients (HR 3.412, p = 0.002 and HR 2.615, p = 0.029, respectively). Conclusions: It can be concluded that a reduced CLDN12 expression predicts a poor outcome for cervical cancer. The novel anti-CLDN12 mAb could be a valuable tool to evaluate the biological relevance of the CLDN12 expression in diverse cancer types and other diseases.
Collapse
|
32
|
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.
Collapse
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
| |
Collapse
|
33
|
Tight Junction Modulating Bioprobes for Drug Delivery System to the Brain: A Review. Pharmaceutics 2020; 12:pharmaceutics12121236. [PMID: 33352631 PMCID: PMC7767277 DOI: 10.3390/pharmaceutics12121236] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 12/16/2020] [Accepted: 12/17/2020] [Indexed: 12/19/2022] Open
Abstract
The blood-brain barrier (BBB), which is composed of endothelial cells, pericytes, astrocytes, and neurons, separates the brain extracellular fluid from the circulating blood, and maintains the homeostasis of the central nervous system (CNS). The BBB endothelial cells have well-developed tight junctions (TJs) and express specific polarized transport systems to tightly control the paracellular movements of solutes, ions, and water. There are two types of TJs: bicellular TJs (bTJs), which is a structure at the contact of two cells, and tricellular TJs (tTJs), which is a structure at the contact of three cells. Claudin-5 and angulin-1 are important components of bTJs and tTJs in the brain, respectively. Here, we review TJ-modulating bioprobes that enable drug delivery to the brain across the BBB, focusing on claudin-5 and angulin-1.
Collapse
|
34
|
Role of Genetic Mutations of the Na +/H + Exchanger Isoform 1, in Human Disease and Protein Targeting and Activity. Mol Cell Biochem 2020; 476:1221-1232. [PMID: 33201382 DOI: 10.1007/s11010-020-03984-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Accepted: 11/06/2020] [Indexed: 01/22/2023]
Abstract
The mammalian Na+/H+ exchanger isoform one (NHE1) is a plasma membrane protein that is ubiquitously present in human cells. It functions to regulate intracellular pH removing an intracellular proton in exchange for one extracellular sodium and is involved in heart disease and in promoting metastasis in cancer. It is made of a 500 amino acid membrane domain plus a 315 amino acid, regulatory cytosolic tail. The membrane domain is thought to have 12 transmembrane segments and a large membrane-associated extracellular loop. Early studies demonstrated that in mice, disruption of the NHE1 gene results in locomotor ataxia and a phenotype of slow-wave epilepsy. Defects included a progressive neuronal degeneration. Growth and reproductive ability were also reduced. Recent studies have identified human autosomal homozygous recessive mutations in the NHE1 gene (SLC9A1) that result in impaired development, ataxia and other severe defects, and explain the cause of the human disease Lichtenstein-Knorr syndrome. Other human mutations have been identified that are stop codon polymorphisms. These cause short non-functional NHE1 proteins, while other genetic polymorphisms in the NHE1 gene cause impaired expression of the NHE1 protein, reduced activity, enhanced protein degradation or altered kinetic activation of the protein. Since NHE1 plays a key role in many human physiological functions and in human disease, genetic polymorphisms of the protein that significantly alter its function and are likely play significant roles in varying human phenotypes and be involved in disease.
Collapse
|
35
|
Special Issue on "The Tight Junction and Its Proteins: More than Just a Barrier". Int J Mol Sci 2020; 21:ijms21134612. [PMID: 32610530 PMCID: PMC7370070 DOI: 10.3390/ijms21134612] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Accepted: 06/26/2020] [Indexed: 12/12/2022] Open
Abstract
For a long time, the tight junction (TJ) was known to form and regulate the paracellular barrier between epithelia and endothelial cell sheets. Starting shortly after the discovery of the proteins forming the TJ—mainly, the two families of claudins and TAMPs—several other functions have been discovered, a striking one being the surprising finding that some claudins form paracellular channels for small ions and/or water. This Special Issue covers numerous dedicated topics including pathogens affecting the TJ barrier, TJ regulation via immune cells, the TJ as a therapeutic target, TJ and cell polarity, the function of and regulation by proteins of the tricellular TJ, the TJ as a regulator of cellular processes, organ- and tissue-specific functions, TJs as sensors and reactors to environmental conditions, and last, but not least, TJ proteins and cancer. It is not surprising that due to this diversity of topics and functions, the still-young field of TJ research is growing fast. This Editorial gives an introduction to all 43 papers of the Special Issue in a structured topical order.
Collapse
|