1
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Kashlan OB, Wang XP, Sheng S, Kleyman TR. Epithelial Na + Channels Function as Extracellular Sensors. Compr Physiol 2024; 14:1-41. [PMID: 39109974 PMCID: PMC11309579 DOI: 10.1002/cphy.c230015] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/10/2024]
Abstract
The epithelial Na + channel (ENaC) resides on the apical surfaces of specific epithelia in vertebrates and plays a critical role in extracellular fluid homeostasis. Evidence that ENaC senses the external environment emerged well before the molecular identity of the channel was reported three decades ago. This article discusses progress toward elucidating the mechanisms through which specific external factors regulate ENaC function, highlighting insights gained from structural studies of ENaC and related family members. It also reviews our understanding of the role of ENaC regulation by the extracellular environment in physiology and disease. After familiarizing the reader with the channel's physiological roles and structure, we describe the central role protein allostery plays in ENaC's sensitivity to the external environment. We then discuss each of the extracellular factors that directly regulate the channel: proteases, cations and anions, shear stress, and other regulators specific to particular extracellular compartments. For each regulator, we discuss the initial observations that led to discovery, studies investigating molecular mechanism, and the physiological and pathophysiological implications of regulation. © 2024 American Physiological Society. Compr Physiol 14:5407-5447, 2024.
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Affiliation(s)
- Ossama B. Kashlan
- Department of Medicine, Renal-Electrolyte Division,
University of Pittsburgh, Pittsburgh, Pennsylvania
- Department of Computational and Systems Biology, University
of Pittsburgh, Pittsburgh, Pennsylvania
| | - Xue-Ping Wang
- Department of Medicine, Renal-Electrolyte Division,
University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Shaohu Sheng
- Department of Medicine, Renal-Electrolyte Division,
University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Thomas R. Kleyman
- Department of Medicine, Renal-Electrolyte Division,
University of Pittsburgh, Pittsburgh, Pennsylvania
- Department of Cell Biology, University of Pittsburgh,
Pittsburgh, Pennsylvania
- Department of Pharmacology and Chemical Biology, University
of Pittsburgh, Pittsburgh, Pennsylvania
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2
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Andrini O, Eladari D, Picard N. ClC-K Kidney Chloride Channels: From Structure to Pathology. Handb Exp Pharmacol 2024; 283:35-58. [PMID: 36811727 DOI: 10.1007/164_2023_635] [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] [Indexed: 02/24/2023]
Abstract
The molecular basis of chloride transport varies all along the nephron depending on the tubular segments especially in the apical entry of the cell. The major chloride exit pathway during reabsorption is provided by two kidney-specific ClC chloride channels ClC-Ka and ClC-Kb (encoded by CLCNKA and CLCNKB gene, respectively) corresponding to rodent ClC-K1 and ClC-K2 (encoded by Clcnk1 and Clcnk2). These channels function as dimers and their trafficking to the plasma membrane requires the ancillary protein Barttin (encoded by BSND gene). Genetic inactivating variants of the aforementioned genes lead to renal salt-losing nephropathies with or without deafness highlighting the crucial role of ClC-Ka, ClC-Kb, and Barttin in the renal and inner ear chloride handling. The purpose of this chapter is to summarize the latest knowledge on renal chloride structure peculiarity and to provide some insight on the functional expression on the segments of the nephrons and on the related pathological effects.
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Affiliation(s)
- Olga Andrini
- Univ Lyon, University Claude Bernard Lyon 1, CNRS UMR 5284, INSERM U 1314, Melis, Lyon, France.
| | - Dominique Eladari
- CHU Amiens Picardie, Service de Médecine de Précision des maladies Métaboliques et Rénales, Université de Picardie Jules Verne, Amiens, France
| | - Nicolas Picard
- CNRS, LBTI UMR5305, Université Claude Bernard Lyon 1, Lyon, France
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3
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Zhong J, Dong J, Ruan W, Duan X. Potential Theranostic Roles of SLC4 Molecules in Human Diseases. Int J Mol Sci 2023; 24:15166. [PMID: 37894847 PMCID: PMC10606849 DOI: 10.3390/ijms242015166] [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: 08/29/2023] [Revised: 09/28/2023] [Accepted: 10/03/2023] [Indexed: 10/29/2023] Open
Abstract
The solute carrier family 4 (SLC4) is an important protein responsible for the transport of various ions across the cell membrane and mediating diverse physiological functions, such as the ion transporting function, protein-to-protein interactions, and molecular transduction. The deficiencies in SLC4 molecules may cause multisystem disease involving, particularly, the respiratory system, digestive, urinary, endocrine, hematopoietic, and central nervous systems. Currently, there are no effective strategies to treat these diseases. SLC4 proteins are also found to contribute to tumorigenesis and development, and some of them are regarded as therapeutic targets in quite a few clinical trials. This indicates that SLC4 proteins have potential clinical prospects. In view of their functional characteristics, there is a critical need to review the specific functions of bicarbonate transporters, their related diseases, and the involved pathological mechanisms. We summarize the diseases caused by the mutations in SLC4 family genes and briefly introduce the clinical manifestations of these diseases as well as the current treatment strategies. Additionally, we illustrate their roles in terms of the physiology and pathogenesis that has been currently researched, which might be the future therapeutic and diagnostic targets of diseases and a new direction for drug research and development.
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Affiliation(s)
| | | | | | - Xiaohong Duan
- State Key Laboratory of Oral & Maxillofacial Reconstruction and Regeneration, National Clinical Research Center for Oral Disease, Shaanxi Key Laboratory of Stomatology, Department of Oral Biology & Clinic of Oral Rare Diseases and Genetic Diseases, School of Stomatology, The Fourth Military Medical University, Xi’an 710032, China; (J.Z.); (J.D.); (W.R.)
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4
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Wen J, Chen SL, Xu WY, Zheng GD, Zou SM. Effects of high NaHCO 3 alkalinity on growth, tissue structure, digestive enzyme activity, and gut microflora of grass carp juvenile. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:85223-85236. [PMID: 37386223 DOI: 10.1007/s11356-023-28083-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Accepted: 05/31/2023] [Indexed: 07/01/2023]
Abstract
With the gradual decrease in freshwater resources, the available space for freshwater aquaculture is diminishing. As a result, saline-alkaline water aquaculture has emerged as a crucial method to fulfill the increasing demand. This study investigates the impact of alkaline water on the growth performance, tissues (gill, liver, and kidney), digestive enzyme activity, and intestinal microbiology in grass carp (Ctenopharyngodon idella). The aquarium conditions were set with sodium bicarbonate (18 mmol/L (LAW), 32 mmol/L (HAW)) to simulate the alkaline water environment. A freshwater group was the control (FW). The experimental fish were cultured for 60 days. The findings revealed that NaHCO3 alkaline stress significantly reduced growth performance, caused alterations in the structural morphology of gill lamellae, liver, and kidney tissues, and led to decreased activity of intestinal trypsin and lipase amylase (P < 0.05). Analysis of 16S rRNA sequences demonstrated that alkalinity influenced the abundance of dominant bacterial phyla and genera. Proteobacteria showed a significant decrease under alkaline conditions, while Firmicutes exhibited a significant increase (P < 0.05). Furthermore, alkalinity conditions significantly reduced the abundance of bacteria involved in protein, amino acid, and carbohydrate metabolism, cell transport, cell decomposition, and environmental information processing. Conversely, the abundance of bacteria associated with lipid metabolism, energy metabolism, organic systems, and disease functional flora increased significantly under alkalinity conditions (P < 0.05). In conclusion, this comprehensive study indicates that alkalinity stress adversely affected the growth performance of juvenile grass carp, likely due to tissue damage, reduced activity of intestinal digestive enzymes, and alterations in intestinal microorganisms.
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Affiliation(s)
- Jian Wen
- Genetics and Breeding Center for Blunt Snout Bream, Ministry of Agriculture and Rural Affairs, Shanghai Ocean University, Shanghai, 201306, China
- Key Laboratory of Freshwater Aquatic Genetic Resources, Ministry of Agriculture and Rural Affairs, Shanghai Ocean University, Shanghai, 201306, China
- National Demonstration Center for Experimental Fisheries Science Education, Shanghai Ocean University, Shanghai, 201306, China
| | - Song-Lin Chen
- Genetics and Breeding Center for Blunt Snout Bream, Ministry of Agriculture and Rural Affairs, Shanghai Ocean University, Shanghai, 201306, China
- Key Laboratory of Freshwater Aquatic Genetic Resources, Ministry of Agriculture and Rural Affairs, Shanghai Ocean University, Shanghai, 201306, China
- National Demonstration Center for Experimental Fisheries Science Education, Shanghai Ocean University, Shanghai, 201306, China
| | - Wen-Ya Xu
- Genetics and Breeding Center for Blunt Snout Bream, Ministry of Agriculture and Rural Affairs, Shanghai Ocean University, Shanghai, 201306, China
- Key Laboratory of Freshwater Aquatic Genetic Resources, Ministry of Agriculture and Rural Affairs, Shanghai Ocean University, Shanghai, 201306, China
- National Demonstration Center for Experimental Fisheries Science Education, Shanghai Ocean University, Shanghai, 201306, China
| | - Guo-Dong Zheng
- Genetics and Breeding Center for Blunt Snout Bream, Ministry of Agriculture and Rural Affairs, Shanghai Ocean University, Shanghai, 201306, China
- Key Laboratory of Freshwater Aquatic Genetic Resources, Ministry of Agriculture and Rural Affairs, Shanghai Ocean University, Shanghai, 201306, China
- National Demonstration Center for Experimental Fisheries Science Education, Shanghai Ocean University, Shanghai, 201306, China
| | - Shu-Ming Zou
- Genetics and Breeding Center for Blunt Snout Bream, Ministry of Agriculture and Rural Affairs, Shanghai Ocean University, Shanghai, 201306, China.
- Key Laboratory of Freshwater Aquatic Genetic Resources, Ministry of Agriculture and Rural Affairs, Shanghai Ocean University, Shanghai, 201306, China.
- National Demonstration Center for Experimental Fisheries Science Education, Shanghai Ocean University, Shanghai, 201306, China.
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5
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Xue JY, Ikegawa S, Guo L. SLC4A2, another gene involved in acid-base balancing machinery of osteoclasts, causes osteopetrosis. Bone 2023; 167:116603. [PMID: 36343920 DOI: 10.1016/j.bone.2022.116603] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Revised: 09/30/2022] [Accepted: 11/01/2022] [Indexed: 11/06/2022]
Abstract
SLC4A2 belongs to the Na+-independent solute carrier family 4 (SLC4) of anion exchangers, which regulate electroneutral exchange of Cl- for HCO3- and mediate intra- and extra-cellular pH, chloride concentration and cell volume. Slc4a2 also participates in gastric acid secretion, spermatogenesis and osteoclastogenesis. During osteoclast differentiation, Slc4a2 is exclusively expressed at the contra-lacunar membrane and is up-regulated with osteoclast maturation. Bi-allelic Slc4a2 loss-of-function mutations have been known to cause osteopetrosis in mice and cattle, but not in human. Recently, we have identified bi-allelic pathogenic variants in SLC4A2 in a patient affected by osteopetrosis with severe renal insufficiency, suggesting SLC4A2 deficiency causes a new type of autosomal recessive osteopetrosis (osteopetrosis, Ikegawa type). In this article, we review the advances in exploring the multiple functions of SLC4A2 with emphasis on its roles in osteoclast. Our review would contribute to understanding of the phenotypic spectrum and the pathomechanism of SLC4A2-associated osteopetrosis.
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Affiliation(s)
- Jing-Yi Xue
- Shaanxi Institute for Pediatric Diseases, Xi'an Children's Hospital, Affiliated Children's Hospital of Xi'an Jiaotong University, Xi'an 710082, China
| | - Shiro Ikegawa
- Laboratory for Bone and Joint Diseases, RIKEN Center for Integrative Medical Sciences, Tokyo 108-8639, Japan
| | - Long Guo
- Shaanxi Institute for Pediatric Diseases, Xi'an Children's Hospital, Affiliated Children's Hospital of Xi'an Jiaotong University, Xi'an 710082, China; Department of Laboratory Animal Science, School of Basic Medical Sciences, Xi'an Jiaotong University, Xi'an 710061, China.
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6
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Xue JY, Grigelioniene G, Wang Z, Nishimura G, Iida A, Matsumoto N, Tham E, Miyake N, Ikegawa S, Guo L. SLC4A2 Deficiency Causes a New Type of Osteopetrosis. J Bone Miner Res 2022; 37:226-235. [PMID: 34668226 DOI: 10.1002/jbmr.4462] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 10/04/2021] [Accepted: 10/07/2021] [Indexed: 02/05/2023]
Abstract
Osteopetrosis is a group of rare inherited skeletal disorders characterized by a marked increase in bone density due to deficient bone resorption. Pathogenic variants in several genes involved in osteoclast differentiation and/or function have been reported to cause osteopetrosis. Solute carrier family 4 member 2 (SLC4A2, encoding anion exchanger 2) plays an important role in osteoclast differentiation and function by exchange of Cl- with HCO3- . Biallelic Slc4a2 loss-of-function mutations in mice and cattle lead to osteopetrosis with osteoclast deficiency; however, pathogenic SLC4A2 variants in humans have not been reported. In this study, we describe a patient with autosomal recessive osteopetrosis due to biallelic pathogenic variants in SLC4A2. We identified novel compound heterozygous variants in SLC4A2 (NM_003040.4: c.556G>A [p.A186T] and c.1658T>C [p.V553A]) by exome sequencing. The measurement of intracellular Cl- showed that the variants decrease the anion exchange activity of SLC4A2. The impact of the variants on osteoclast differentiation was assessed by a gene knockout-rescue system using a mouse macrophage cell line, RAW 264.7. The Slc4a2-knockout cells show impaired osteoclastogenesis, which was rescued by the wild-type SLC4A2, but not by the mutant SLC4A2s. Immunofluorescence and pit assay revealed that the mutant SLC4A2s leads to abnormal podosome belt formation with impaired bone absorption. This is the first report on an individual affected by SLC4A2-associated osteopetrosis (osteopetrosis, Ikegawa type). With functional studies, we prove that the variants lead to SLC4A2 dysfunction, which altogether supports the importance of SLC4A2 in human osteoclast differentiation. © 2021 American Society for Bone and Mineral Research (ASBMR).
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Affiliation(s)
- Jing-Yi Xue
- Laboratory for Bone and Joint Diseases, RIKEN Center for Integrative Medical Sciences, Tokyo, Japan.,Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Giedre Grigelioniene
- Department of Molecular Medicine and Surgery, Karolinska Institutet, and Clinical Genetics, Karolinska University Laboratory, Karolinska University Hospital, Stockholm, Sweden
| | - Zheng Wang
- Laboratory for Bone and Joint Diseases, RIKEN Center for Integrative Medical Sciences, Tokyo, Japan.,Department of Medical Genetics, Institute of Basic Medical Sciences, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China
| | - Gen Nishimura
- Laboratory for Bone and Joint Diseases, RIKEN Center for Integrative Medical Sciences, Tokyo, Japan
| | - Aritoshi Iida
- Laboratory for Bone and Joint Diseases, RIKEN Center for Integrative Medical Sciences, Tokyo, Japan.,Department of Clinical Genome Analysis, Medical Genome Center, National Center of Neurology and Psychiatry, Kodaira, Japan
| | - Naomichi Matsumoto
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Emma Tham
- Department of Molecular Medicine and Surgery, Karolinska Institutet, and Clinical Genetics, Karolinska University Laboratory, Karolinska University Hospital, Stockholm, Sweden
| | - Noriko Miyake
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Shiro Ikegawa
- Laboratory for Bone and Joint Diseases, RIKEN Center for Integrative Medical Sciences, Tokyo, Japan
| | - Long Guo
- Laboratory for Bone and Joint Diseases, RIKEN Center for Integrative Medical Sciences, Tokyo, Japan
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7
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Beaume J, Figueres L, Bobot M, de Laforcade L, Ayari H, Dolley-Hitze T, Gueutin V, Braconnier A, Golbin L, Citarda S, Seret G, Belaïd L, Cohen R, Luque Y, Larceneux F, Seervai RNH, Overs C, Bertocchio JP. Sodium Bicarbonate Prescription and Extracellular Volume Increase: Real-world Data Results from the AlcalUN Study. Clin Pharmacol Ther 2021; 111:252-262. [PMID: 34564842 DOI: 10.1002/cpt.2427] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Accepted: 09/13/2021] [Indexed: 11/11/2022]
Abstract
Oral alkalization with sodium bicarbonate (NaHCO3 ) or citrate is prescribed for conditions ranging from metabolic acidosis to nephrolithiasis. Although most nephrologists/urologists use this method routinely, extracellular volume (ECV) increase is the main feared adverse event reported for NaHCO3 . Thus far, no trial has specifically studied this issue in a real-world setting. AlcalUN (NCT03035812) is a multicentric, prospective, open-label cohort study with nationwide (France) enrollment in 18 (public and private) nephrology/urology units. Participants were adult outpatients requiring chronic (>1 month) oral alkalization by either NaHCO3 -containing or no-NaHCO3 -containing agents. The ECV increase (primary outcome) was judged based on body weight increase (ΔBW), blood pressure increase (ΔBP), and/or new-onset edema at the first follow-up visit (V1). From February 2017 to February 2020, 156 patients were enrolled. After a median 106 days of treatment, 91 (72%) patients reached the primary outcome. They had lower systolic (135 (125, 141) vs. 141 (130, 150), P = 0.02) and diastolic (77 (67, 85) vs. 85 (73, 90), P = 0.03) BP values, a higher plasma chloride (106.0 (105.0, 109.0) vs. 105.0 (102.0, 107.0), P = 0.02) at baseline, and a less frequent history of nephrolithiasis (32 vs. 56%, P = 0.02). Patients experienced mainly slight ΔBP (< 10 mmHg). The primary outcome was not associated (P = 0.79) with the study treatment (129 received NaHCO3 and 27 received citrate). We subsequently developed three different models of propensity score matching; each confirmed our results. Chronic oral alkalization with NaHCO3 is no longer associated with an ECV increase compared to citrate in real-life settings.
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Affiliation(s)
- Julie Beaume
- AVODD, HIA Sainte-Anne, Toulon, France.,Club des Jeunes Néphrologues, Paris, France
| | - Lucile Figueres
- Club des Jeunes Néphrologues, Paris, France.,DIVAT Consortium, Nantes, France.,Service de Néphrologie et d'immunologie clinique, ITUN, CHU de Nantes, Université de Nantes, Nantes, France
| | - Mickaël Bobot
- Club des Jeunes Néphrologues, Paris, France.,Centre de Néphrologie et Transplantation Rénale, Assistance Publique Hôpitaux de Marseille, Hôpital de la Conception, Marseille, France.,C2VN, INSERM 1263, INRAE 1260, Aix-Marseille Université, Marseille, France
| | - Louis de Laforcade
- Club des Jeunes Néphrologues, Paris, France.,Service Endocrinologie-Néphrologie, Centre Hospitalier Pierre Oudot, Bourgoin-Jallieu, France
| | - Hamza Ayari
- Renal and Metabolic Diseases Unit, European Georges Pompidou Hospital, AP-HP, Paris, France
| | - Thibault Dolley-Hitze
- Club des Jeunes Néphrologues, Paris, France.,Unité de dialyse de Saint-Malo, Fondation AUB Santé, Saint-Malo, France
| | - Victor Gueutin
- Service de Néphrologie-Dialyse, AURA Paris Plaisance, Paris, France.,Service de Néphrologie, Hôpital de La Pitié-Salpêtrière, AP-HP, Paris, France
| | - Antoine Braconnier
- Club des Jeunes Néphrologues, Paris, France.,Service de Néphrologie, Dialyse et Transplantation Rénale, CHU Reims, Hôpital Maison Blanche, Reims, France
| | - Léonard Golbin
- Club des Jeunes Néphrologues, Paris, France.,Service de Néphrologie, Dialyse et Transplantation Rénale, CHU Rennes, Hôpital Pontchaillou, Rennes, France
| | - Salvatore Citarda
- Club des Jeunes Néphrologues, Paris, France.,Centre associatif lyonnais de dialyse (Calydial), Irigny, France
| | | | - Lisa Belaïd
- Unité de dialyse de Saint-Malo, Fondation AUB Santé, Saint-Malo, France
| | - Raphaël Cohen
- Renal and Metabolic Diseases Unit, European Georges Pompidou Hospital, AP-HP, Paris, France
| | - Yosu Luque
- Club des Jeunes Néphrologues, Paris, France.,Urgences Néphrologiques et Transplantation Rénale, Hôpital Tenon, AP-HP, UMR_S1155, Sorbonne Université, Paris, France
| | - Fabrice Larceneux
- CNRS, UMR (7088), DRM, (ERMES), Université Paris-Dauphine, PSL Research University, Paris, France
| | - Riyad N H Seervai
- Center for Precision Environmental Health, Baylor College of Medicine, Houston, Texas, USA.,Molecular & Cellular Biology Graduate Program, Medical Scientist Training Program, Baylor College of Medicine, Houston, Texas, USA
| | - Camille Overs
- Association Française des Urologues en Formation, Paris, France.,Service d'Urologie, Andrologie et transplantation Rénale, CHU de Grenoble, La Tronche, France
| | - Jean-Philippe Bertocchio
- Club des Jeunes Néphrologues, Paris, France.,Service de Néphrologie, Hôpital de La Pitié-Salpêtrière, AP-HP, Paris, France
| | -
- Club des Jeunes Néphrologues, Paris, France
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8
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Bertocchio JP, Genetet S, Da Costa L, Walsh SB, Knebelmann B, Galimand J, Bessenay L, Guitton C, De Lafaille R, Vargas-Poussou R, Eladari D, Mouro-Chanteloup I. Red Blood Cell AE1/Band 3 Transports in Dominant Distal Renal Tubular Acidosis Patients. Kidney Int Rep 2020; 5:348-357. [PMID: 32154456 PMCID: PMC7056926 DOI: 10.1016/j.ekir.2019.12.020] [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: 10/26/2019] [Revised: 11/26/2019] [Accepted: 12/31/2019] [Indexed: 11/30/2022] Open
Abstract
Introduction Anion exchanger 1 (AE1) (SLC4A1 gene product) is a membrane protein expressed in both kidney and red blood cells (RBCs): it exchanges extracellular bicarbonate (HCO3–) for intracellular chloride (Cl–) and participates in acid−base homeostasis. AE1 mutations in kidney α-intercalated cells can lead to distal renal tubular acidosis (dRTA). In RBC, AE1 (known as band 3) is also implicated in membrane stability: deletions can cause South Asian ovalocytosis (SAO). Methods We retrospectively collected clinical and biological data from patients harboring dRTA due to a SLC4A1 mutation and analyzed HCO3– and Cl– transports (by stopped-flow spectrophotometry) and expression (by flow cytometry, fluorescence activated cell sorting, and Coomassie blue staining) in RBCs, as well as RBC membrane stability (ektacytometry). Results Fifteen patients were included. All experience nephrolithiasis and/or nephrocalcinosis, 2 had SAO and dRTA (dRTA SAO+), 13 dominant dRTA (dRTA SAO−). The latter did not exert specific RBC membrane anomalies. Both HCO3– and Cl– transports were lower in patients with dRTA SAO+ than in those with dRTA SAO− or controls. Using 3 different extracellular probes, we report a decreased expression (by 52%, P < 0.05) in dRTA SAO+ patients by fluorescence activated cell sorting, whereas total amount of protein was not affected. Conclusion Band 3 transport function and expression in RBCs from dRTA SAO− patients is normal. However, in SAO RBCs, impaired conformation of AE1/band 3 corresponds to an impaired function. Thus, the driver of acid−base defect during dominant dRTA is probably an impaired membrane expression.
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Affiliation(s)
- Jean-Philippe Bertocchio
- Renal and Metabolic Diseases Unit, Assistance Publique-Hôpitaux de Paris, European Georges Pompidou Hospital, Paris, France.,Faculty of Medicine, Paris Descartes University, Paris, France.,Reference Center for Maladies Rénales Héréditaires de l'Enfant et de l'Adulte (MARHEA), Paris, France.,Genito-urinary Medical Oncology and Research Department, MD Anderson Cancer Center, Houston, Texas, USA
| | - Sandrine Genetet
- UMR_S1134, Integrated Red Globule Biology (IRGB), Inserm, University of Paris, Paris, France.,Team 1, Physiology of Normal and Pathologic Red Blood Cell, Institut National de la Transfusion Sanguine (INTS), Paris, France
| | - Lydie Da Costa
- UMR_S1134, Integrated Red Globule Biology (IRGB), Inserm, University of Paris, Paris, France.,UMR_S1134, Inserm, Paris, France.,Service d'Hématologie Biologique, Assistance Publique-Hôpitaux de Paris, Hôpital Robert Debré, Paris, France
| | - Stephen B Walsh
- Department of Renal Medicine, University College of London, London, UK
| | - Bertrand Knebelmann
- Nephrology Department, Assistance Publique-Hôpitaux de Paris, Necker-Enfants Malades Hospital, Paris, France
| | - Julie Galimand
- Service d'Hématologie Biologique, Assistance Publique-Hôpitaux de Paris, Hôpital Robert Debré, Paris, France
| | - Lucie Bessenay
- Pediatrics Department, University Hospital of Clermont-Ferrand, Clermont-Ferrand, France
| | - Corinne Guitton
- Pediatrics Department, Assistance Publique-Hôpitaux de Paris, Hôpital Bicêtre, Le Kremlin Bicêtre, France
| | - Renaud De Lafaille
- Nephrology Department, University Hospital of Bordeaux, Bordeaux, Aquitaine, France
| | - Rosa Vargas-Poussou
- Reference Center for Maladies Rénales Héréditaires de l'Enfant et de l'Adulte (MARHEA), Paris, France.,Institut National pour la Santé et la Recherche Médicale (INSERM), Unité Mixte de Recherche UMRS1138, Cordeliers Research Center, Paris, France.,Genetics Department, Assistance Publique-Hôpitaux de Paris, European Georges Pompidou Hospital, Paris, France
| | - Dominique Eladari
- Renal and Metabolic Diseases Department, CHU de la Réunion, Felix Guyon Hospital, Saint Denis, France.,INSERM, UMRS 1283-European Genomic Institute for Diabetes, Lille, France
| | - Isabelle Mouro-Chanteloup
- UMR_S1134, Integrated Red Globule Biology (IRGB), Inserm, University of Paris, Paris, France.,Team 1, Physiology of Normal and Pathologic Red Blood Cell, Institut National de la Transfusion Sanguine (INTS), Paris, France
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9
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Kashoor I, Batlle D. Proximal renal tubular acidosis with and without Fanconi syndrome. Kidney Res Clin Pract 2019; 38:267-281. [PMID: 31474092 PMCID: PMC6727890 DOI: 10.23876/j.krcp.19.056] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Revised: 06/13/2019] [Accepted: 06/19/2019] [Indexed: 01/02/2023] Open
Abstract
Proximal renal tubular acidosis (RTA) is caused by a defect in bicarbonate (HCO3−) reabsorption in the kidney proximal convoluted tubule. It usually manifests as normal anion-gap metabolic acidosis due to HCO3− wastage. In a normal kidney, the thick ascending limb of Henle’s loop and more distal nephron segments reclaim all of the HCO3− not absorbed by the proximal tubule. Bicarbonate wastage seen in type II RTA indicates that the proximal tubular defect is severe enough to overwhelm the capacity for HCO3− reabsorption beyond the proximal tubule. Proximal RTA can occur as an isolated syndrome or with other impairments in proximal tubular functions under the spectrum of Fanconi syndrome. Fanconi syndrome, which is characterized by a defect in proximal tubular reabsorption of glucose, amino acids, uric acid, phosphate, and HCO3−, can occur due to inherited or acquired causes. Primary inherited Fanconi syndrome is caused by a mutation in the sodium-phosphate cotransporter (NaPi-II) in the proximal tubule. Recent studies have identified new causes of Fanconi syndrome due to mutations in the EHHADH and the HNF4A genes. Fanconi syndrome can also be one of many manifestations of various inherited systemic diseases, such as cystinosis. Many of the acquired causes of Fanconi syndrome with or without proximal RTA are drug-induced, with the list of causative agents increasing as newer drugs are introduced for clinical use, mainly in the oncology field.
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Affiliation(s)
- Ibrahim Kashoor
- Division of Nephrology and Hypertension, Department of Medicine, The Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Daniel Batlle
- Division of Nephrology and Hypertension, Department of Medicine, The Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
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10
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Finer G, Landau D. Clinical Approach to Proximal Renal Tubular Acidosis in Children. Adv Chronic Kidney Dis 2018; 25:351-357. [PMID: 30139461 DOI: 10.1053/j.ackd.2018.05.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Proximal renal tubular acidosis (pRTA) is an inherited or acquired clinical syndrome in which there is a decreased bicarbonate reclamation in the proximal tubule resulting in normal anion gap hyperchloremic metabolic acidosis. In children, pRTA may be isolated but is often associated with a general proximal tubular dysfunction known as Fanconi syndrome which frequently heralds an underlying systemic disorder from which it arises. When accompanied by Fanconi syndrome, pRTA is characterized by additional renal wasting of phosphate, glucose, uric acid, and amino acids. The most common cause of inherited Fanconi syndrome in the pediatric age group is cystinosis, a disease with therapeutic implications. In this article, we summarize the clinical presentation and differential diagnosis of pRTA and Fanconi syndrome and provide a practical approach to their evaluation in children.
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11
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Bicarbonate : de la physiologie aux applications thérapeutiques pour tout clinicien. Nephrol Ther 2018; 14:13-23. [DOI: 10.1016/j.nephro.2017.02.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Accepted: 02/22/2017] [Indexed: 11/17/2022]
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12
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Parker MD. Mouse models of SLC4-linked disorders of HCO 3--transporter dysfunction. Am J Physiol Cell Physiol 2018; 314:C569-C588. [PMID: 29384695 DOI: 10.1152/ajpcell.00301.2017] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The SLC4 family Cl-/[Formula: see text] cotransporters (NBCe1, NBCe2, NBCn1, and NBCn2) contribute to a variety of vital physiological processes including pH regulation and epithelial fluid secretion. Accordingly, their dysfunction can have devastating effects. Disorders such as epilepsy, hemolytic anemia, glaucoma, hearing loss, osteopetrosis, and renal tubular acidosis are all genetically linked to SLC4-family gene loci. This review summarizes how studies of Slc4-modified mice have enhanced our understanding of the etiology of SLC4-linked pathologies and the interpretation of genetic linkage studies. The review also surveys the novel disease signs exhibited by Slc4-modified mice which could either be considered to presage their description in humans, or to highlight interspecific differences. Finally, novel Slc4-modified mouse models are proposed, the study of which may further our understanding of the basis and treatment of SLC4-linked disorders of [Formula: see text]-transporter dysfunction.
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Affiliation(s)
- Mark D Parker
- Department of Physiology and Biophysics, The State University of New York: The University at Buffalo , Buffalo, New York.,Department of Ophthalmology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo: The State University of New York , Buffalo, New York.,State University of New York Eye Institutes, University at Buffalo: The State University of New York , Buffalo, New York
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13
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Ring T, Nielsen S. Whole body acid-base modeling revisited. Am J Physiol Renal Physiol 2016; 312:F647-F653. [PMID: 28031171 DOI: 10.1152/ajprenal.00560.2016] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Revised: 12/14/2016] [Accepted: 12/21/2016] [Indexed: 01/15/2023] Open
Abstract
The textbook account of whole body acid-base balance in terms of endogenous acid production, renal net acid excretion, and gastrointestinal alkali absorption, which is the only comprehensive model around, has never been applied in clinical practice or been formally validated. To improve understanding of acid-base modeling, we managed to write up this conventional model as an expression solely on urine chemistry. Renal net acid excretion and endogenous acid production were already formulated in terms of urine chemistry, and we could from the literature also see gastrointestinal alkali absorption in terms of urine excretions. With a few assumptions it was possible to see that this expression of net acid balance was arithmetically identical to minus urine charge, whereby under the development of acidosis, urine was predicted to acquire a net negative charge. The literature already mentions unexplained negative urine charges so we scrutinized a series of seminal papers and confirmed empirically the theoretical prediction that observed urine charge did acquire negative charge as acidosis developed. Hence, we can conclude that the conventional model is problematic since it predicts what is physiologically impossible. Therefore, we need a new model for whole body acid-base balance, which does not have impossible implications. Furthermore, new experimental studies are needed to account for charge imbalance in urine under development of acidosis.
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Affiliation(s)
- Troels Ring
- Department of Nephrology, Aalborg University Hospital, Aalborg, Denmark; and .,Department of Health and Science Technology, Faculty of Medicine, Aalborg University, Aalborg, Denmark
| | - Søren Nielsen
- Department of Health and Science Technology, Faculty of Medicine, Aalborg University, Aalborg, Denmark
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14
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Xu J, Li JT, Jiang Y, Peng W, Yao Z, Chen B, Jiang L, Feng J, Ji P, Liu G, Liu Z, Tai R, Dong C, Sun X, Zhao ZX, Zhang Y, Wang J, Li S, Zhao Y, Yang J, Sun X, Xu P. Genomic Basis of Adaptive Evolution: The Survival of Amur Ide (Leuciscus waleckii) in an Extremely Alkaline Environment. Mol Biol Evol 2016; 34:145-159. [PMID: 28007977 PMCID: PMC5854124 DOI: 10.1093/molbev/msw230] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The Amur ide (Leuciscus waleckii) is a cyprinid fish that is widely distributed in Northeast Asia. The Lake Dali Nur population inhabits one of the most extreme aquatic environments on Earth, with an alkalinity up to 50 mmol/L (pH 9.6), thus providing an exceptional model with which to characterize the mechanisms of genomic evolution underlying adaptation to extreme environments. Here, we developed the reference genome assembly for L. waleckii from Lake Dali Nur. Intriguingly, we identified unusual expanded long terminal repeats (LTRs) with higher nucleotide substitution rates than in many other teleosts, suggesting their more recent insertion into the L. waleckii genome. We also identified expansions in genes encoding egg coat proteins and natriuretic peptide receptors, possibly underlying the adaptation to extreme environmental stress. We further sequenced the genomes of 10 additional individuals from freshwater and 18 from Lake Dali Nur populations, and we detected a total of 7.6 million SNPs from both populations. In a genome scan and comparison of these two populations, we identified a set of genomic regions under selective sweeps that harbor genes involved in ion homoeostasis, acid-base regulation, unfolded protein response, reactive oxygen species elimination, and urea excretion. Our findings provide comprehensive insight into the genomic mechanisms of teleost fish that underlie their adaptation to extreme alkaline environments.
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Affiliation(s)
- Jian Xu
- Beijing Key Laboratory of Fishery Biotechnology, Centre for Applied Aquatic Genomics, Chinese Academy of Fishery Sciences, Beijing, China
| | - Jiong-Tang Li
- Beijing Key Laboratory of Fishery Biotechnology, Centre for Applied Aquatic Genomics, Chinese Academy of Fishery Sciences, Beijing, China
| | - Yanliang Jiang
- Beijing Key Laboratory of Fishery Biotechnology, Centre for Applied Aquatic Genomics, Chinese Academy of Fishery Sciences, Beijing, China
| | - Wenzhu Peng
- Beijing Key Laboratory of Fishery Biotechnology, Centre for Applied Aquatic Genomics, Chinese Academy of Fishery Sciences, Beijing, China.,State Key Laboratory of Marine Environmental Science, College of Ocean & Earth Science, Xiamen University, Xiamen, China
| | - Zongli Yao
- Engineering Research Centre for Saline-alkaline Fisheries, East China Sea Fisheries Research Institute, Chinese Academy of Fisheries Sciences, Shanghai, China
| | - Baohua Chen
- Beijing Key Laboratory of Fishery Biotechnology, Centre for Applied Aquatic Genomics, Chinese Academy of Fishery Sciences, Beijing, China
| | - Likun Jiang
- Beijing Key Laboratory of Fishery Biotechnology, Centre for Applied Aquatic Genomics, Chinese Academy of Fishery Sciences, Beijing, China
| | - Jingyan Feng
- Beijing Key Laboratory of Fishery Biotechnology, Centre for Applied Aquatic Genomics, Chinese Academy of Fishery Sciences, Beijing, China
| | - Peifeng Ji
- Beijing Key Laboratory of Fishery Biotechnology, Centre for Applied Aquatic Genomics, Chinese Academy of Fishery Sciences, Beijing, China
| | - Guiming Liu
- CAS Key Laboratory of Genome Sciences and Information, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing, China
| | - Zhanjiang Liu
- The Fish Molecular Genetics and Biotechnology Laboratory, Aquatic Genomics Unit, School of Fisheries, Aquaculture and Aquatic Sciences, Auburn University, Auburn, AL
| | - Ruyu Tai
- Beijing Key Laboratory of Fishery Biotechnology, Centre for Applied Aquatic Genomics, Chinese Academy of Fishery Sciences, Beijing, China
| | - Chuanju Dong
- Beijing Key Laboratory of Fishery Biotechnology, Centre for Applied Aquatic Genomics, Chinese Academy of Fishery Sciences, Beijing, China
| | - Xiaoqing Sun
- Beijing Key Laboratory of Fishery Biotechnology, Centre for Applied Aquatic Genomics, Chinese Academy of Fishery Sciences, Beijing, China
| | - Zi-Xia Zhao
- Beijing Key Laboratory of Fishery Biotechnology, Centre for Applied Aquatic Genomics, Chinese Academy of Fishery Sciences, Beijing, China
| | - Yan Zhang
- Beijing Key Laboratory of Fishery Biotechnology, Centre for Applied Aquatic Genomics, Chinese Academy of Fishery Sciences, Beijing, China
| | - Jian Wang
- Division of Animal and Nutritional Sciences, West Virginia University, Morgantown, WV
| | - Shangqi Li
- Beijing Key Laboratory of Fishery Biotechnology, Centre for Applied Aquatic Genomics, Chinese Academy of Fishery Sciences, Beijing, China
| | - Yunfeng Zhao
- Beijing Key Laboratory of Fishery Biotechnology, Centre for Applied Aquatic Genomics, Chinese Academy of Fishery Sciences, Beijing, China
| | - Jiuhui Yang
- Dalinor National Nature Reserve, Keshiketeng, Chifeng, China
| | - Xiaowen Sun
- Beijing Key Laboratory of Fishery Biotechnology, Centre for Applied Aquatic Genomics, Chinese Academy of Fishery Sciences, Beijing, China
| | - Peng Xu
- Beijing Key Laboratory of Fishery Biotechnology, Centre for Applied Aquatic Genomics, Chinese Academy of Fishery Sciences, Beijing, China .,State Key Laboratory of Marine Environmental Science, College of Ocean & Earth Science, Xiamen University, Xiamen, China.,Fujian Collaborative Innovation Centre for Exploitation and Utilization of Marine Biological Resources, Xiamen University, Xiamen, China
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15
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Gymnocypris przewalskii decreases cytosolic carbonic anhydrase expression to compensate for respiratory alkalosis and osmoregulation in the saline-alkaline lake Qinghai. J Comp Physiol B 2015; 186:83-95. [DOI: 10.1007/s00360-015-0939-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2015] [Revised: 09/27/2015] [Accepted: 10/04/2015] [Indexed: 12/29/2022]
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