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Guo W, Ji P, Xie Y. Genetic diagnosis and treatment of hereditary renal tubular disease with hypokalemia and alkalosis. J Nephrol 2023; 36:575-591. [PMID: 35994232 DOI: 10.1007/s40620-022-01428-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Accepted: 07/29/2022] [Indexed: 10/15/2022]
Abstract
Renal tubules play an important role in maintaining water, electrolyte, and acid-base balance. Renal tubule dysfunction can cause electrolyte disorders and acid-base imbalance. Clinically, hypokalemic renal tubular disease is the most common tubule disorder. With the development of molecular genetics and gene sequencing technology, hereditary renal tubular diseases have attracted attention, and an increasing number of pathogenic genes related to renal tubular diseases have been discovered and reported. Inherited renal tubular diseases mainly occur due to mutations in genes encoding various specific transporters or ion channels expressed on the tubular epithelial membrane, leading to dysfunctional renal tubular reabsorption, secretion, and excretion. An in-depth understanding of the molecular genetic basis of hereditary renal tubular disease will help to understand the physiological function of renal tubules, the mechanism by which the kidney maintains water, electrolyte, and acid-base balance, and the relationship between the kidney and other systems in the body. Meanwhile, understanding these diseases also improves our understanding of the pathogenesis of hypokalemia, alkalosis and other related diseases and ultimately promotes accurate diagnostics and effective disease treatment. The present review summarizes the most common hereditary renal tubular diseases (Bartter syndrome, Gitelman syndrome, EAST syndrome and Liddle syndrome) characterized by hypokalemia and alkalosis. Further detailed explanations are provided for pathogenic genes and functional proteins, clinical manifestations, intrinsic relationship between genotype and clinical phenotype, diagnostic clues, differential diagnosis, and treatment strategies for these diseases.
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Affiliation(s)
- Wenkai Guo
- Department of Nephrology, First Medical Center of Chinese PLA General Hospital, Chinese PLA Institute of Nephrology, State Key Laboratory of Kidney Diseases, National Clinical Research Center for Kidney Diseases, Beijing, 100853, People's Republic of China
- School of Medicine, Nankai University, Tianjin, 300071, People's Republic of China
| | - Pengcheng Ji
- Department of Nephrology, First Medical Center of Chinese PLA General Hospital, Chinese PLA Institute of Nephrology, State Key Laboratory of Kidney Diseases, National Clinical Research Center for Kidney Diseases, Beijing, 100853, People's Republic of China
| | - Yuansheng Xie
- Department of Nephrology, First Medical Center of Chinese PLA General Hospital, Chinese PLA Institute of Nephrology, State Key Laboratory of Kidney Diseases, National Clinical Research Center for Kidney Diseases, Beijing, 100853, People's Republic of China.
- School of Medicine, Nankai University, Tianjin, 300071, People's Republic of China.
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Scorza SI, Milano S, Saponara I, Certini M, De Zio R, Mola MG, Procino G, Carmosino M, Moccia F, Svelto M, Gerbino A. TRPML1-Induced Lysosomal Ca 2+ Signals Activate AQP2 Translocation and Water Flux in Renal Collecting Duct Cells. Int J Mol Sci 2023; 24:ijms24021647. [PMID: 36675161 PMCID: PMC9861594 DOI: 10.3390/ijms24021647] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Revised: 01/04/2023] [Accepted: 01/11/2023] [Indexed: 01/19/2023] Open
Abstract
Lysosomes are acidic Ca2+ storage organelles that actively generate local Ca2+ signaling events to regulate a plethora of cell functions. Here, we characterized lysosomal Ca2+ signals in mouse renal collecting duct (CD) cells and we assessed their putative role in aquaporin 2 (AQP2)-dependent water reabsorption. Bafilomycin A1 and ML-SA1 triggered similar Ca2+ oscillations, in the absence of extracellular Ca2+, by alkalizing the acidic lysosomal pH or activating the lysosomal cation channel mucolipin 1 (TRPML1), respectively. TRPML1-dependent Ca2+ signals were blocked either pharmacologically or by lysosomes' osmotic permeabilization, thus indicating these organelles as primary sources of Ca2+ release. Lysosome-induced Ca2+ oscillations were sustained by endoplasmic reticulum (ER) Ca2+ content, while bafilomycin A1 and ML-SA1 did not directly interfere with ER Ca2+ homeostasis per se. TRPML1 activation strongly increased AQP2 apical expression and depolymerized the actin cytoskeleton, thereby boosting water flux in response to an hypoosmotic stimulus. These effects were strictly dependent on the activation of the Ca2+/calcineurin pathway. Conversely, bafilomycin A1 led to perinuclear accumulation of AQP2 vesicles without affecting water permeability. Overall, lysosomal Ca2+ signaling events can be differently decoded to modulate Ca2+-dependent cellular functions related to the dock/fusion of AQP2-transporting vesicles in principal cells of the CD.
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Affiliation(s)
- Simona Ida Scorza
- Department of Biosciences, Biotechnologies and Environment, University of Bari Aldo Moro, 70125 Bari, Italy
| | - Serena Milano
- Department of Biosciences, Biotechnologies and Environment, University of Bari Aldo Moro, 70125 Bari, Italy
| | - Ilenia Saponara
- Department of Biosciences, Biotechnologies and Environment, University of Bari Aldo Moro, 70125 Bari, Italy
| | - Maira Certini
- Department of Biosciences, Biotechnologies and Environment, University of Bari Aldo Moro, 70125 Bari, Italy
| | - Roberta De Zio
- Department of Biosciences, Biotechnologies and Environment, University of Bari Aldo Moro, 70125 Bari, Italy
| | - Maria Grazia Mola
- Department of Biosciences, Biotechnologies and Environment, University of Bari Aldo Moro, 70125 Bari, Italy
| | - Giuseppe Procino
- Department of Biosciences, Biotechnologies and Environment, University of Bari Aldo Moro, 70125 Bari, Italy
| | - Monica Carmosino
- Department of Sciences, University of Basilicata, 85100 Potenza, Italy
| | - Francesco Moccia
- Department of Biology and Biotechnology Lazzaro Spallanzani, University of Pavia, 27100 Pavia, Italy
| | - Maria Svelto
- Department of Biosciences, Biotechnologies and Environment, University of Bari Aldo Moro, 70125 Bari, Italy
| | - Andrea Gerbino
- Department of Biosciences, Biotechnologies and Environment, University of Bari Aldo Moro, 70125 Bari, Italy
- Correspondence: ; Tel.: +39-0805443334
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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.
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Nuñez-Gonzalez L, Carrera N, Garcia-Gonzalez MA. Molecular Basis, Diagnostic Challenges and Therapeutic Approaches of Bartter and Gitelman Syndromes: A Primer for Clinicians. Int J Mol Sci 2021; 22:11414. [PMID: 34768847 PMCID: PMC8584233 DOI: 10.3390/ijms222111414] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 10/13/2021] [Accepted: 10/14/2021] [Indexed: 12/18/2022] Open
Abstract
Gitelman and Bartter syndromes are rare inherited diseases that belong to the category of renal tubulopathies. The genes associated with these pathologies encode electrolyte transport proteins located in the nephron, particularly in the Distal Convoluted Tubule and Ascending Loop of Henle. Therefore, both syndromes are characterized by alterations in the secretion and reabsorption processes that occur in these regions. Patients suffer from deficiencies in the concentration of electrolytes in the blood and urine, which leads to different systemic consequences related to these salt-wasting processes. The main clinical features of both syndromes are hypokalemia, hypochloremia, metabolic alkalosis, hyperreninemia and hyperaldosteronism. Despite having a different molecular etiology, Gitelman and Bartter syndromes share a relevant number of clinical symptoms, and they have similar therapeutic approaches. The main basis of their treatment consists of electrolytes supplements accompanied by dietary changes. Specifically for Bartter syndrome, the use of non-steroidal anti-inflammatory drugs is also strongly supported. This review aims to address the latest diagnostic challenges and therapeutic approaches, as well as relevant recent research on the biology of the proteins involved in disease. Finally, we highlight several objectives to continue advancing in the characterization of both etiologies.
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Affiliation(s)
- Laura Nuñez-Gonzalez
- Grupo de Xenetica e Bioloxia do Desenvolvemento das Enfermidades Renais, Laboratorio de Nefroloxia (No. 11), Instituto de Investigacion Sanitaria de Santiago (IDIS), Complexo Hospitalario de Santiago de Compostela (CHUS), 15706 Santiago de Compostela, Spain;
- Grupo de Medicina Xenomica, Complexo Hospitalario de Santiago de Compostela (CHUS), 15706 Santiago de Compostela, Spain
| | - Noa Carrera
- Grupo de Xenetica e Bioloxia do Desenvolvemento das Enfermidades Renais, Laboratorio de Nefroloxia (No. 11), Instituto de Investigacion Sanitaria de Santiago (IDIS), Complexo Hospitalario de Santiago de Compostela (CHUS), 15706 Santiago de Compostela, Spain;
- Grupo de Medicina Xenomica, Complexo Hospitalario de Santiago de Compostela (CHUS), 15706 Santiago de Compostela, Spain
- RedInRen (Red en Investigación Renal) RETIC (Redes Temáticas de Investigación Cooperativa en Salud), ISCIII (Instituto de Salud Carlos III), 28029 Madrid, Spain
| | - Miguel A. Garcia-Gonzalez
- Grupo de Xenetica e Bioloxia do Desenvolvemento das Enfermidades Renais, Laboratorio de Nefroloxia (No. 11), Instituto de Investigacion Sanitaria de Santiago (IDIS), Complexo Hospitalario de Santiago de Compostela (CHUS), 15706 Santiago de Compostela, Spain;
- Grupo de Medicina Xenomica, Complexo Hospitalario de Santiago de Compostela (CHUS), 15706 Santiago de Compostela, Spain
- RedInRen (Red en Investigación Renal) RETIC (Redes Temáticas de Investigación Cooperativa en Salud), ISCIII (Instituto de Salud Carlos III), 28029 Madrid, Spain
- Fundación Pública Galega de Medicina Xenomica—SERGAS, Complexo Hospitalario de Santiago de Compotela (CHUS), 15706 Santiago de Compostela, Spain
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Mrad FCC, Soares SBM, de Menezes Silva LAW, Dos Anjos Menezes PV, Simões-E-Silva AC. Bartter's syndrome: clinical findings, genetic causes and therapeutic approach. World J Pediatr 2021; 17:31-39. [PMID: 32488762 DOI: 10.1007/s12519-020-00370-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Accepted: 05/24/2020] [Indexed: 02/07/2023]
Abstract
BACKGOUND Bartter's syndrome (BS) is a rare group of salt losing tubulopathies due to the impairment of transport mechanisms at the thick ascending limb of the Henle's loop. DATA SOURCES Literature reviews and original research articles were collected from database, including PubMed and Scopus. RESULTS According to the time of onset and symptoms, BS can be classified into antenatal and classic BS. Molecular studies have identified different subtypes of BS. BS types I, II and III are caused by mutations on genes encoding the luminal Na+-K+-2Cl- co-transporter, the luminal K+ channel ROMK, and the basolateral chloride channel ClC-Kb (CLCNKB), respectively. Loss-of-function mutations of Barttin CLCNK type accessory beta subunit cause BS type IVa. Simultaneous mutations of CLCNKB and CLCNKA cause BS type IVb. BS type V consists in a novel transient form characterized by antenatal presentation due to mutations in the MAGE family member D2. Severe gain-of-function mutations of the extracellular calcium sensing receptor gene can result in an autosomal dominant condition of BS. Main clinical and biochemical alterations in BS include polyuria, dehydration, hypokalemia, hypochloremic metabolic alkalosis, hyperreninemia, high levels of prostaglandins, normal or low blood pressure, hypercalciuria and failure to thrive. Treatment focuses mainly at correcting dehydration and electrolyte disturbances and in measures to reduce polyuria, including the use of nonsteroidal anti-inflammatory medications to control excessive renal prostaglandin E2 production. CONCLUSIONS Early diagnosis and treatment of BS may prevent long-term consequences such as growth failure, nephrocalcinosis and end-stage renal disease.
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Affiliation(s)
- Flavia Cristina Carvalho Mrad
- Interdisciplinary Laboratory of Medical Investigation, Faculty of Medicine, Federal University of Minas Gerais (UFMG), Av. Prof. Alfredo Balena, 190, Room # 281, Belo Horizonte, MG 30130-100, Brazil.,Pediatric Nephrology Unit, Faculty of Medicine, UFMG, Belo Horizonte, Brazil
| | - Sílvia Bouissou Morais Soares
- Interdisciplinary Laboratory of Medical Investigation, Faculty of Medicine, Federal University of Minas Gerais (UFMG), Av. Prof. Alfredo Balena, 190, Room # 281, Belo Horizonte, MG 30130-100, Brazil
| | - Luiz Alberto Wanderley de Menezes Silva
- Interdisciplinary Laboratory of Medical Investigation, Faculty of Medicine, Federal University of Minas Gerais (UFMG), Av. Prof. Alfredo Balena, 190, Room # 281, Belo Horizonte, MG 30130-100, Brazil
| | - Pedro Versiani Dos Anjos Menezes
- Interdisciplinary Laboratory of Medical Investigation, Faculty of Medicine, Federal University of Minas Gerais (UFMG), Av. Prof. Alfredo Balena, 190, Room # 281, Belo Horizonte, MG 30130-100, Brazil
| | - Ana Cristina Simões-E-Silva
- Interdisciplinary Laboratory of Medical Investigation, Faculty of Medicine, Federal University of Minas Gerais (UFMG), Av. Prof. Alfredo Balena, 190, Room # 281, Belo Horizonte, MG 30130-100, Brazil.
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Marcoux AA, Tremblay LE, Slimani S, Fiola MJ, Mac-Way F, Garneau AP, Isenring P. Molecular characteristics and physiological roles of Na + -K + -Cl - cotransporter 2. J Cell Physiol 2020; 236:1712-1729. [PMID: 32776569 PMCID: PMC7818487 DOI: 10.1002/jcp.29997] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Revised: 06/28/2020] [Accepted: 07/24/2020] [Indexed: 12/23/2022]
Abstract
Na+–K+–Cl− cotransporter 2 (NKCC2; SLC12A1) is an integral membrane protein that comes as three splice variants and mediates the cotranslocation of Na+, K+, and Cl− ions through the apical membrane of the thick ascending loop of Henle (TALH). In doing so, and through the involvement of other ion transport systems, it allows this nephron segment to reclaim a large fraction of the ultrafiltered Na+, Cl−, Ca2+, Mg2+, and HCO3− loads. The functional relevance of NKCC2 in human is illustrated by the many abnormalities that result from the inactivation of this transport system through the use of loop diuretics or in the setting of inherited disorders. The following presentation aims at discussing the physiological roles and molecular characteristics of Na+–K+–Cl− cotransport in the TALH and those of the individual NKCC2 splice variants more specifically. Many of the historical and recent data that have emerged from the experiments conducted will be outlined and their larger meaning will also be placed into perspective with the aid of various hypotheses.
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Affiliation(s)
- Andree-Anne Marcoux
- Department of Medicine, Nephrology Research Group, Laval University, Quebec City, Québec, Canada
| | - Laurence E Tremblay
- Department of Medicine, Nephrology Research Group, Laval University, Quebec City, Québec, Canada
| | - Samira Slimani
- Department of Medicine, Nephrology Research Group, Laval University, Quebec City, Québec, Canada
| | - Marie-Jeanne Fiola
- Department of Medicine, Nephrology Research Group, Laval University, Quebec City, Québec, Canada
| | - Fabrice Mac-Way
- Department of Medicine, Nephrology Research Group, Laval University, Quebec City, Québec, Canada
| | - Alexandre P Garneau
- Department of Medicine, Nephrology Research Group, Laval University, Quebec City, Québec, Canada.,Cardiometabolic Axis, School of Kinesiology and Physical Activity Sciences, University of Montréal, Montréal, Quebec, Canada
| | - Paul Isenring
- Department of Medicine, Nephrology Research Group, Laval University, Quebec City, Québec, Canada
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Calcium-Sensing Receptor and Regulation of WNK Kinases in the Kidney. Cells 2020; 9:cells9071644. [PMID: 32659887 PMCID: PMC7407487 DOI: 10.3390/cells9071644] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 07/01/2020] [Accepted: 07/06/2020] [Indexed: 12/27/2022] Open
Abstract
The kidney is essential for systemic calcium homeostasis. Urinary calcium excretion can be viewed as an integrative renal response to endocrine and local stimuli. The extracellular calcium-sensing receptor (CaSR) elicits a number of adaptive reactions to increased plasma Ca2+ levels including the control of parathyroid hormone release and regulation of the renal calcium handling. Calcium reabsorption in the distal nephron of the kidney is functionally coupled to sodium transport. Apart from Ca2+ transport systems, CaSR signaling affects relevant distal Na+-(K+)-2Cl- cotransporters, NKCC2 and NCC. NKCC2 and NCC are activated by a kinase cascade comprising with-no-lysine [K] kinases (WNKs) and two homologous Ste20-related kinases, SPAK and OSR1. Gain-of-function mutations within the WNK-SPAK/OSR1-NKCC2/NCC pathway lead to renal salt retention and hypertension, whereas loss-of-function mutations have been associated with salt-losing tubulopathies such as Bartter or Gitelman syndromes. A Bartter-like syndrome has been also described in patients carrying gain-of-function mutations in the CaSR gene. Recent work suggested that CaSR signals via the WNK-SPAK/OSR1 cascade to modulate salt reabsorption along the distal nephron. The review presented here summarizes the latest progress in understanding of functional interactions between CaSR and WNKs and their potential impact on the renal salt handling and blood pressure.
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Abstract
PURPOSE OF REVIEW Antenatal Bartter's syndrome (aBS) is the most severe form of Bartter's syndrome, requiring close follow-up, in particular during the neonatal period, primarily because of prematurity. The recent identification of a novel and very severe form of aBS merits an update on this topic. RECENT FINDING Despite the identification of several genes involved in Bartter's syndrome, about 20% of patients clinically diagnosed with aBS remained without genetic explanation for decades. We recently identified mutations in MAGED2 as a cause of an X-linked form of aBS characterized by a very early onset of severe polyhydramnios and extreme prematurity leading to high mortality. Remarkably, all symptoms in surviving patients with MAGE-D2 mutations resolve spontaneously, within weeks after preterm birth. Interestingly, MAGE-D2 affects the expression of the sodium chloride cotransporters NKCC2 and NCC, explaining thereby the severity of the disease. Importantly, a more recent analysis of MAGED2 in a large French cohort of patients with aBS confirmed our data and showed that females can also be affected. SUMMARY MAGE-D2 is critical for renal salt reabsorption in the fetus, amniotic fluid volume regulation, and maintenance of pregnancy. Most importantly, MAGED2 must be included in the genetic screening of every form of aBS.
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Abstract
Bartter syndrome is an inherited renal tubular disorder caused by a defective salt reabsorption in the thick ascending limb of loop of Henle, resulting in salt wasting, hypokalemia, and metabolic alkalosis. Mutations of several genes encoding the transporters and channels involved in salt reabsorption in the thick ascending limb cause different types of Bartter syndrome. A poor phenotype-genotype relationship due to the interaction with other cotransporters and different degrees of compensation through alternative pathways is currently reported. However, phenotypic identification still remains the first step to guide the suspicion of Bartter syndrome. Given the rarity of the syndrome, and the lack of genetic characterization in most cases, limited clinical evidence for treatment is available and the therapy is based mainly on the comprehension of renal physiology and relies on the physician's personal experiences. A better understanding of the mutated channels and transporters could possibly generate targets for specific treatment in the future, also encompassing drugs aiming to correct deficiencies in folding or plasma membrane expression of the mutated proteins.
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Affiliation(s)
- Tamara da Silva Cunha
- Nephrology Division, Universidade Federal de São Paulo (UNIFESP), Escola Paulista de Medicina, São Paulo, Brazil,
| | - Ita Pfeferman Heilberg
- Nephrology Division, Universidade Federal de São Paulo (UNIFESP), Escola Paulista de Medicina, São Paulo, Brazil,
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Future considerations based on the information from Barrter's and Gitelman's syndromes. Curr Opin Nephrol Hypertens 2018; 26:9-13. [PMID: 27798456 DOI: 10.1097/mnh.0000000000000285] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE OF REVIEW Bartter and Gitelman syndromes are typical normotensive salt losing hypokalaemic tubulopathies. Their pathogenesis was gradually deciphered in the past 5 decades, first by typical salt balance studies and histopathology, followed by genetic characterization and discovery of the affected different ion channels. Although the different genotypic subtypes were originally thought to show a similar phenotype, important clinical and biochemical differences can now be found. New findings on the regulation of these channels, as well as the recent discovery of newly affected genes, merit an update on this topic. RECENT FINDINGS Na-K-2CL cotransporter and NaCl cotransporter, the two main luminal channels in the thick ascending limb and distal convoluted tubule were found to be regulated by Ste 20-related proline alanine-rich kinase and oxidative stress response kinase. Knockout mice to these channels express a Bartter-like phenotype. MAGE-D2 is new gene found to cause severe polyhydramnios and transient postnatal Bartter-like syndrome. Variants in the different channels causing Bartter syndromes/Gitelman syndromes may also confer susceptibility for hypertension or protect against it. SUMMARY It remains to be determined if polymorphism or epigenetic changes in these genes and proteins may affect salt handling, explaining, apart from Bartter syndromes and Gitelman syndromes, also hypertension or stroke tendency, or both.
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Dandelion Root Extract Induces Intracellular Ca 2+ Increases in HEK293 Cells. Int J Mol Sci 2018; 19:ijms19041112. [PMID: 29642457 PMCID: PMC5979456 DOI: 10.3390/ijms19041112] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Revised: 03/29/2018] [Accepted: 04/04/2018] [Indexed: 02/07/2023] Open
Abstract
Dandelion (Taraxacum officinale Weber ex F.H.Wigg.) has been used for centuries as an ethnomedical remedy. Nonetheless, the extensive use of different kinds of dandelion extracts and preparations is based on empirical findings. Some of the tissue-specific effects reported for diverse dandelion extracts may result from their action on intracellular signaling cascades. Therefore, the aim of this study was to evaluate the effects of an ethanolic dandelion root extract (DRE) on Ca2+ signaling in human embryonic kidney (HEK) 293 cells. The cytotoxicity of increasing doses of crude DRE was determined by the Calcein viability assay. Fura-2 and the fluorescence resonance energy transfer (FRET)-based probe ERD1 were used to measure cytoplasmic and intraluminal endoplasmic reticulum (ER) Ca2+ levels, respectively. Furthermore, a green fluorescent protein (GFP)-based probe was used to monitor phospholipase C (PLC) activation (pleckstrin homology [PH]–PLCδ–GFP). DRE (10–400 µg/mL) exposure, in the presence of external Ca2+, dose-dependently increased intracellular Ca2+ levels. The DRE-induced Ca2+ increase was significantly reduced in the absence of extracellular Ca2+. In addition, DRE caused a significant Ca2+ release from the ER of intact cells and a concomitant translocation of PH–PLCδ–GFP. In conclusion, DRE directly activates both the release of Ca2+ from internal stores and a significant Ca2+ influx at the plasma membrane. The resulting high Ca2+ levels within the cell seem to directly stimulate PLC activity.
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12
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Gerbino A, Colella M. The Different Facets of Extracellular Calcium Sensors: Old and New Concepts in Calcium-Sensing Receptor Signalling and Pharmacology. Int J Mol Sci 2018; 19:E999. [PMID: 29584660 PMCID: PMC5979557 DOI: 10.3390/ijms19040999] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Revised: 03/23/2018] [Accepted: 03/25/2018] [Indexed: 12/14/2022] Open
Abstract
The current interest of the scientific community for research in the field of calcium sensing in general and on the calcium-sensing Receptor (CaR) in particular is demonstrated by the still increasing number of papers published on this topic. The extracellular calcium-sensing receptor is the best-known G-protein-coupled receptor (GPCR) able to sense external Ca2+ changes. Widely recognized as a fundamental player in systemic Ca2+ homeostasis, the CaR is ubiquitously expressed in the human body where it activates multiple signalling pathways. In this review, old and new notions regarding the mechanisms by which extracellular Ca2+ microdomains are created and the tools available to measure them are analyzed. After a survey of the main signalling pathways triggered by the CaR, a special attention is reserved for the emerging concepts regarding CaR function in the heart, CaR trafficking and pharmacology. Finally, an overview on other Ca2+ sensors is provided.
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Affiliation(s)
- Andrea Gerbino
- Department of Biosciences, Biotechnology and Biopharmaceutics, University of Bari, 70121 Bari, Italy.
| | - Matilde Colella
- Department of Biosciences, Biotechnology and Biopharmaceutics, University of Bari, 70121 Bari, Italy.
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13
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Carmosino M, Gerbino A, Schena G, Procino G, Miglionico R, Forleo C, Favale S, Svelto M. The expression of Lamin A mutant R321X leads to endoplasmic reticulum stress with aberrant Ca 2+ handling. J Cell Mol Med 2016; 20:2194-2207. [PMID: 27421120 PMCID: PMC5082401 DOI: 10.1111/jcmm.12926] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Accepted: 06/07/2016] [Indexed: 01/13/2023] Open
Abstract
Mutations in the Lamin A/C gene (LMNA), which encodes A‐type nuclear Lamins, represent the most frequent genetic cause of dilated cardiomyopathy (DCM). This study is focused on a LMNA nonsense mutation (R321X) identified in several members of an Italian family that produces a truncated protein isoform, which co‐segregates with a severe form of cardiomyopathy with poor prognosis. However, no molecular mechanisms other than nonsense mediated decay of the messenger and possible haploinsufficiency were proposed to explain DCM. Aim of this study was to gain more insights into the disease‐causing mechanisms induced by the expression of R321X at cellular level. We detected the expression of R321X by Western blotting from whole lysate of a mutation carrier heart biopsy. When expressed in HEK293 cells, GFP‐ (or mCherry)‐tagged R321X mislocalized in the endoplasmic reticulum (ER) inducing the PERK‐CHOP axis of the ER stress response. Of note, confocal microscopy showed phosphorylation of PERK in sections of the mutation carrier heart biopsy. ER mislocalization of mCherry‐R321X also induced impaired ER Ca2+ handling, reduced capacitative Ca2+ entry at the plasma membrane and abnormal nuclear Ca2+ dynamics. In addition, expression of R321X by itself increased the apoptosis rate. In conclusion, R321X is the first LMNA mutant identified to date, which mislocalizes into the ER affecting cellular homeostasis mechanisms not strictly related to nuclear functions.
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Affiliation(s)
- Monica Carmosino
- Department of Sciences, University of Basilicata, Potenza, Italy.
| | - Andrea Gerbino
- Department of Biosciences, Biotechnology and Biopharmaceutics, University of Bari, Bari, Italy
| | - Giorgia Schena
- Department of Sciences, University of Basilicata, Potenza, Italy
| | - Giuseppe Procino
- Department of Biosciences, Biotechnology and Biopharmaceutics, University of Bari, Bari, Italy
| | | | - Cinzia Forleo
- Cardiology Unit, Department of Emergency and Organ Transplantation, University of Bari, Bari, Italy
| | - Stefano Favale
- Cardiology Unit, Department of Emergency and Organ Transplantation, University of Bari, Bari, Italy
| | - Maria Svelto
- Department of Biosciences, Biotechnology and Biopharmaceutics, University of Bari, Bari, Italy.,Consiglio Nazionale delle Ricerche, Bari, Italy
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Spilanthol from Acmella Oleracea Lowers the Intracellular Levels of cAMP Impairing NKCC2 Phosphorylation and Water Channel AQP2 Membrane Expression in Mouse Kidney. PLoS One 2016; 11:e0156021. [PMID: 27213818 PMCID: PMC4877099 DOI: 10.1371/journal.pone.0156021] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Accepted: 05/09/2016] [Indexed: 11/19/2022] Open
Abstract
Acmella oleracea is well recognized in Brazilian traditional medicine as diuretic, although few scientific data have been published to support this effect. Aim of this study was to determine the molecular effect of Acmella oleracea extract and its main alkylamide spilanthol on two major processes involved in the urine concentrating mechanism: Na-K-2Cl symporter (NKCC2) activity in the thick ascending limb and water channel aquaporin 2 accumulation at the apical plasma membrane of collecting duct cells. Phosphorylation of NKCC2 was evaluated as index of its activation by Western blotting. Rate of aquaporin 2 apical expression was analyzed by confocal laser microscopy. Spilanthol-induced intracellular signalling events were dissected by video-imaging experiments. Exposure to spilanthol reduced the basal phosphorylation level of NKCC2 both in freshly isolated mouse kidney slices and in NKCC2-expresing HEK293 cells. In addition, exposure to spilanthol strongly reduced both desmopressin and low Cl−-dependent increase in NKCC2 phosphorylation in mouse kidney slices and NKCC2-expressing HEK293 cells, respectively. Similarly, spilanthol reduced both desmopressin- and forskolin-stimulated aquaporin 2 accumulation at the apical plasma membrane of collecting duct in mouse kidney slice and MCD4 cells, respectively. Of note, when orally administered, spilanthol induced a significant increase in both urine output and salt urinary excretion associated with a markedly reduced urine osmolality compared with control mice. Finally, at cellular level, spilanthol rapidly reduced or reversed basal and agonist-increased cAMP levels through a mechanism involving increases in intracellular [Ca2+]. In conclusion, spilanthol-induced inhibition of cAMP production negatively modulates urine-concentrating mechanisms thus holding great promise for its use as diuretic.
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Kamiyoshi N, Nozu K, Urahama Y, Matsunoshita N, Yamamura T, Minamikawa S, Ninchoji T, Morisada N, Nakanishi K, Kaito H, Iijima K. Pathogenesis of hypokalemia in autosomal dominant hypocalcemia type 1. Clin Exp Nephrol 2015; 20:253-7. [DOI: 10.1007/s10157-015-1160-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Accepted: 08/23/2015] [Indexed: 12/27/2022]
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