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Mayayo-Vallverdú C, Gaitán-Peñas H, Armand-Ugon M, Muhaisen A, Prat E, Castellanos A, Elorza-Vidal X, de Heredia ML, Alonso-Gardón M, Pérez-Rius C, Vecino-Pérez M, Mallen A, Errasti-Murugarren E, Hueso M, Artuch R, Nunes V, Estévez R. Regulation of ClC-K/barttin by endocytosis influences distal convoluted tubule hyperplasia. J Physiol 2024. [PMID: 39106251 DOI: 10.1113/jp286729] [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: 04/11/2024] [Accepted: 07/11/2024] [Indexed: 08/09/2024] Open
Abstract
ClC-K/barttin channels are involved in the transepithelial transport of chloride in the kidney and inner ear. Their physiological role is crucial in humans because mutations in CLCNKB or BSND, encoding ClC-Kb and barttin, cause Bartter's syndrome types III and IV, respectively. In vitro experiments have shown that an amino acid change in a proline-tyrosine motif in the C-terminus of barttin stimulates ClC-K currents. The molecular mechanism of this enhancement and whether this potentiation has any in vivo relevance remains unknown. We performed electrophysiological and biochemical experiments in Xenopus oocytes and kidney cells co-expressing ClC-K and barttin constructs. We demonstrated that barttin possesses a YxxØ motif and, when mutated, increases ClC-K plasma membrane stability, resulting in larger currents. To address the impact of mutating this motif in kidney physiology, we generated a knock-in mouse. Comparing wild-type (WT) and knock-in mice under a standard diet, we could not observe any difference in ClC-K and barttin protein levels or localization, either in urinary or plasma parameters. However, under a high-sodium low-potassium diet, known to induce hyperplasia of distal convoluted tubules, knock-in mice exhibit reduced hyperplasia compared to WT mice. In summary, our in vitro and in vivo studies demonstrate that the previously identified PY motif is indeed an endocytic YxxØ motif in which mutations cause a gain of function of the channel. KEY POINTS: It is revealed by mutagenesis and functional experiments that a previously identified proline-tyrosine motif regulating ClC-K plasma membrane levels is indeed an endocytic YxxØ motif. Biochemical characterization of mutants in the YxxØ motif in Xenopus oocytes and human embryonic kidney cells indicates that mutants showed increased plasma membrane levels as a result of an increased stability, resulting in higher function of ClC-K channels. Mutation of this motif does not affect barttin protein expression and subcellular localization in vivo. Knock-in mice with a mutation in this motif, under conditions of a high-sodium low-potassium diet, exhibit less hyperplasia in the distal convoluted tubule than wild-type animals, indicating a gain of function of the channel in vivo.
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Affiliation(s)
- Clara Mayayo-Vallverdú
- Genes, Disease and Therapy Program, Molecular Genetics Laboratory-IDIBELL, Genetics Section, Department of Physiological Sciences, Faculty of Medicine and Health Sciences, University of Barcelona, Barcelona, Spain
| | - Héctor Gaitán-Peñas
- Physiology Unit, Department of Physiological Sciences, School of Medicine and Health Sciences, Institute of Neurosciences, University of Barcelona, L'Hospitalet de Llobregat, Spain
- Genes, Disease and Therapy Program, Physiology and pathology of the functional relationship between glia and neurons-IDIBELL, L'Hospitalet de Llobregat, Spain
- Centro de Investigación en red de enfermedades raras (CIBERER), Instituto de Salud Carlos III, Madrid, Spain
| | - Mercedes Armand-Ugon
- Physiology Unit, Department of Physiological Sciences, School of Medicine and Health Sciences, Institute of Neurosciences, University of Barcelona, L'Hospitalet de Llobregat, Spain
- Genes, Disease and Therapy Program, Physiology and pathology of the functional relationship between glia and neurons-IDIBELL, L'Hospitalet de Llobregat, Spain
| | - Ashraf Muhaisen
- Physiology Unit, Department of Physiological Sciences, School of Medicine and Health Sciences, Institute of Neurosciences, University of Barcelona, L'Hospitalet de Llobregat, Spain
- Genes, Disease and Therapy Program, Physiology and pathology of the functional relationship between glia and neurons-IDIBELL, L'Hospitalet de Llobregat, Spain
| | - Esther Prat
- Genes, Disease and Therapy Program, Molecular Genetics Laboratory-IDIBELL, Genetics Section, Department of Physiological Sciences, Faculty of Medicine and Health Sciences, University of Barcelona, Barcelona, Spain
| | - Aida Castellanos
- Physiology Unit, Department of Physiological Sciences, School of Medicine and Health Sciences, Institute of Neurosciences, University of Barcelona, L'Hospitalet de Llobregat, Spain
- Genes, Disease and Therapy Program, Physiology and pathology of the functional relationship between glia and neurons-IDIBELL, L'Hospitalet de Llobregat, Spain
- Centro de Investigación en red de enfermedades raras (CIBERER), Instituto de Salud Carlos III, Madrid, Spain
| | - Xabier Elorza-Vidal
- Physiology Unit, Department of Physiological Sciences, School of Medicine and Health Sciences, Institute of Neurosciences, University of Barcelona, L'Hospitalet de Llobregat, Spain
- Genes, Disease and Therapy Program, Physiology and pathology of the functional relationship between glia and neurons-IDIBELL, L'Hospitalet de Llobregat, Spain
- Centro de Investigación en red de enfermedades raras (CIBERER), Instituto de Salud Carlos III, Madrid, Spain
| | - Miguel López de Heredia
- Genes, Disease and Therapy Program, Molecular Genetics Laboratory-IDIBELL, Genetics Section, Department of Physiological Sciences, Faculty of Medicine and Health Sciences, University of Barcelona, Barcelona, Spain
- Centro de Investigación en red de enfermedades raras (CIBERER), Instituto de Salud Carlos III, Madrid, Spain
| | - Marta Alonso-Gardón
- Physiology Unit, Department of Physiological Sciences, School of Medicine and Health Sciences, Institute of Neurosciences, University of Barcelona, L'Hospitalet de Llobregat, Spain
- Genes, Disease and Therapy Program, Physiology and pathology of the functional relationship between glia and neurons-IDIBELL, L'Hospitalet de Llobregat, Spain
| | - Carla Pérez-Rius
- Physiology Unit, Department of Physiological Sciences, School of Medicine and Health Sciences, Institute of Neurosciences, University of Barcelona, L'Hospitalet de Llobregat, Spain
- Genes, Disease and Therapy Program, Physiology and pathology of the functional relationship between glia and neurons-IDIBELL, L'Hospitalet de Llobregat, Spain
| | - Marta Vecino-Pérez
- Genes, Disease and Therapy Program, Molecular Genetics Laboratory-IDIBELL, Genetics Section, Department of Physiological Sciences, Faculty of Medicine and Health Sciences, University of Barcelona, Barcelona, Spain
| | - Adrián Mallen
- Department of Nephrology, Hospital Universitart Bellvitge and Institut d'Investigació Biomèdica de Bellvitge-IDIBELL, L'Hospitalet de Llobregat, Spain
| | - Ekaitz Errasti-Murugarren
- Genes, Disease and Therapy Program, Molecular Genetics Laboratory-IDIBELL, Genetics Section, Department of Physiological Sciences, Faculty of Medicine and Health Sciences, University of Barcelona, Barcelona, Spain
| | - Miguel Hueso
- Department of Nephrology, Hospital Universitart Bellvitge and Institut d'Investigació Biomèdica de Bellvitge-IDIBELL, L'Hospitalet de Llobregat, Spain
| | - Rafael Artuch
- Centro de Investigación en red de enfermedades raras (CIBERER), Instituto de Salud Carlos III, Madrid, Spain
- Institut de Recerca Sant Joan de Déu, Barcelona, Spain
| | - Virginia Nunes
- Genes, Disease and Therapy Program, Molecular Genetics Laboratory-IDIBELL, Genetics Section, Department of Physiological Sciences, Faculty of Medicine and Health Sciences, University of Barcelona, Barcelona, Spain
- Centro de Investigación en red de enfermedades raras (CIBERER), Instituto de Salud Carlos III, Madrid, Spain
| | - Raúl Estévez
- Physiology Unit, Department of Physiological Sciences, School of Medicine and Health Sciences, Institute of Neurosciences, University of Barcelona, L'Hospitalet de Llobregat, Spain
- Genes, Disease and Therapy Program, Physiology and pathology of the functional relationship between glia and neurons-IDIBELL, L'Hospitalet de Llobregat, Spain
- Centro de Investigación en red de enfermedades raras (CIBERER), Instituto de Salud Carlos III, Madrid, Spain
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Knecht DA, Zeziulia M, Bhavsar MB, Puchkov D, Maier H, Jentsch TJ. LRRC8/VRAC volume-regulated anion channels are crucial for hearing. J Biol Chem 2024; 300:107436. [PMID: 38838775 PMCID: PMC11260850 DOI: 10.1016/j.jbc.2024.107436] [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: 01/22/2024] [Revised: 05/09/2024] [Accepted: 05/23/2024] [Indexed: 06/07/2024] Open
Abstract
Hearing crucially depends on cochlear ion homeostasis as evident from deafness elicited by mutations in various genes encoding cation or anion channels and transporters. Ablation of ClC‑K/barttin chloride channels causes deafness by interfering with the positive electrical potential of the endolymph, but roles of other anion channels in the inner ear have not been studied. Here we report the intracochlear distribution of all five LRRC8 subunits of VRAC, a volume-regulated anion channel that transports chloride, metabolites, and drugs such as the ototoxic anti-cancer drug cisplatin, and explore its physiological role by ablating its subunits. Sensory hair cells express all LRRC8 isoforms, whereas only LRRC8A, D and E were found in the potassium-secreting epithelium of the stria vascularis. Cochlear disruption of the essential LRRC8A subunit, or combined ablation of LRRC8D and E, resulted in cochlear degeneration and congenital deafness of Lrrc8a-/- mice. It was associated with a progressive degeneration of the organ of Corti and its innervating spiral ganglion. Like disruption of ClC-K/barttin, loss of VRAC severely reduced the endocochlear potential. However, the mechanism underlying this reduction seems different. Disruption of VRAC, but not ClC-K/barttin, led to an almost complete loss of Kir4.1 (KCNJ10), a strial K+ channel crucial for the generation of the endocochlear potential. The strong downregulation of Kir4.1 might be secondary to a loss of VRAC-mediated transport of metabolites regulating inner ear redox potential such as glutathione. Our study extends the knowledge of the role of cochlear ion transport in hearing and ototoxicity.
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Affiliation(s)
- Deborah A Knecht
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany; Max-Delbrück-Centrum für Molekulare Medizin (MDC), Berlin, Germany
| | - Mariia Zeziulia
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany; Max-Delbrück-Centrum für Molekulare Medizin (MDC), Berlin, Germany; Graduate Program of the Freie Universität Berlin, Berlin, Germany
| | - Mit B Bhavsar
- Department of Otolaryngology, Hannover Medical School, Hannover, Germany
| | - Dmytro Puchkov
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany
| | - Hannes Maier
- Department of Otolaryngology, Hannover Medical School, Hannover, Germany; Cluster of Excellence "Hearing4all", Hannover, Germany
| | - Thomas J Jentsch
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany; NeuroCure Cluster of Excellence, Charité Universitätsmedizin Berlin, Berlin, Germany.
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Zhang Y, Bock F, Ferdaus M, Arroyo JP, L Rose K, Patel P, Denton JS, Delpire E, Weinstein AM, Zhang MZ, Harris RC, Terker AS. Low potassium activation of proximal mTOR/AKT signaling is mediated by Kir4.2. Nat Commun 2024; 15:5144. [PMID: 38886379 PMCID: PMC11183202 DOI: 10.1038/s41467-024-49562-w] [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: 08/31/2023] [Accepted: 06/07/2024] [Indexed: 06/20/2024] Open
Abstract
The renal epithelium is sensitive to changes in blood potassium (K+). We identify the basolateral K+ channel, Kir4.2, as a mediator of the proximal tubule response to K+ deficiency. Mice lacking Kir4.2 have a compensated baseline phenotype whereby they increase their distal transport burden to maintain homeostasis. Upon dietary K+ depletion, knockout animals decompensate as evidenced by increased urinary K+ excretion and development of a proximal renal tubular acidosis. Potassium wasting is not proximal in origin but is caused by higher ENaC activity and depends upon increased distal sodium delivery. Three-dimensional imaging reveals Kir4.2 knockouts fail to undergo proximal tubule expansion, while the distal convoluted tubule response is exaggerated. AKT signaling mediates the dietary K+ response, which is blunted in Kir4.2 knockouts. Lastly, we demonstrate in isolated tubules that AKT phosphorylation in response to low K+ depends upon mTORC2 activation by secondary changes in Cl- transport. Data support a proximal role for cell Cl- which, as it does along the distal nephron, responds to K+ changes to activate kinase signaling.
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Affiliation(s)
- Yahua Zhang
- Division of Nephrology, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
- Vanderbilt Center for Kidney Disease, Nashville, TN, USA
| | - Fabian Bock
- Division of Nephrology, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
- Vanderbilt Center for Kidney Disease, Nashville, TN, USA
| | - Mohammed Ferdaus
- Department of Anesthesiology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Juan Pablo Arroyo
- Division of Nephrology, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
- Vanderbilt Center for Kidney Disease, Nashville, TN, USA
| | - Kristie L Rose
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN, USA
- Mass Spectrometry Research Center, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Purvi Patel
- Mass Spectrometry Research Center, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Jerod S Denton
- Department of Anesthesiology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Eric Delpire
- Department of Anesthesiology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Alan M Weinstein
- Department of Physiology and Biophysics, Weil Medical College, New York, NY, USA
| | - Ming-Zhi Zhang
- Division of Nephrology, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
- Vanderbilt Center for Kidney Disease, Nashville, TN, USA
| | - Raymond C Harris
- Division of Nephrology, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
- Vanderbilt Center for Kidney Disease, Nashville, TN, USA
- Department of Veterans Affairs, Tennessee Valley Healthcare System, Nashville, TN, USA
| | - Andrew S Terker
- Division of Nephrology, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA.
- Vanderbilt Center for Kidney Disease, Nashville, TN, USA.
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Kostritskaia Y, Klüssendorf M, Pan YE, Hassani Nia F, Kostova S, Stauber T. Physiological Functions of the Volume-Regulated Anion Channel VRAC/LRRC8 and the Proton-Activated Chloride Channel ASOR/TMEM206. Handb Exp Pharmacol 2024; 283:181-218. [PMID: 37468723 DOI: 10.1007/164_2023_673] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/21/2023]
Abstract
Volume-regulated anion channels (VRACs) and the acid-sensitive outwardly rectifying anion channel (ASOR) mediate flux of chloride and small organic anions. Although known for a long time, they were only recently identified at the molecular level. VRACs are heteromers consisting of LRRC8 proteins A to E. Combining the essential LRRC8A with different LRRC8 paralogues changes key properties of VRAC such as conductance or substrate selectivity, which is how VRACs are involved in multiple physiological functions including regulatory volume decrease, cell proliferation and migration, cell death, purinergic signalling, fat and glucose metabolism, insulin signalling, and spermiogenesis. VRACs are also involved in pathological conditions, such as the neurotoxic release of glutamate and aspartate. Certain VRACs are also permeable to larger, organic anions, including antibiotics and anti-cancer drugs, making them an interesting therapeutic target. ASOR, also named proton-activated chloride channel (PAC), is formed by TMEM206 homotrimers on the plasma membrane and on endosomal compartments where it mediates chloride flux in response to extracytosolic acidification and plays a role in the shrinking and maturation of macropinosomes. ASOR has been shown to underlie neuronal swelling which causes cell death after stroke as well as promoting the metastasis of certain cancers, making them intriguing therapeutic targets as well.
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Affiliation(s)
- Yulia Kostritskaia
- Institute for Molecular Medicine, MSH Medical School Hamburg, Hamburg, Germany
| | - Malte Klüssendorf
- Institute for Molecular Medicine, MSH Medical School Hamburg, Hamburg, Germany
| | - Yingzhou Edward Pan
- Institute for Molecular Medicine, MSH Medical School Hamburg, Hamburg, Germany
| | - Fatemeh Hassani Nia
- Institute for Molecular Medicine, MSH Medical School Hamburg, Hamburg, Germany
| | - Simona Kostova
- Institute for Molecular Medicine, MSH Medical School Hamburg, Hamburg, Germany
| | - Tobias Stauber
- Institute for Molecular Medicine, MSH Medical School Hamburg, Hamburg, Germany.
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Pyrshev K, Atamanchuk-Stavniichuk A, Kordysh M, Zaika O, Tomilin VN, Pochynyuk O. Independent regulation of Piezo1 activity by principal and intercalated cells of the collecting duct. J Biol Chem 2024; 300:105524. [PMID: 38043795 PMCID: PMC10772730 DOI: 10.1016/j.jbc.2023.105524] [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: 08/28/2023] [Revised: 10/30/2023] [Accepted: 11/21/2023] [Indexed: 12/05/2023] Open
Abstract
The renal collecting duct is continuously exposed to a wide spectrum of fluid flow rates and osmotic gradients. Expression of a mechanoactivated Piezo1 channel is the most prominent in the collecting duct. However, the status and regulation of Piezo1 in functionally distinct principal and intercalated cells (PCs and ICs) of the collecting duct remain to be determined. We used pharmacological Piezo1 activation to quantify Piezo1-mediated [Ca2+]i influx and single-channel activity separately in PCs and ICs of freshly isolated collecting ducts with fluorescence imaging and electrophysiological tools. We also employed a variety of systemic treatments to examine their consequences on Piezo1 function in PCs and ICs. Piezo1 selective agonists, Yoda-1 or Jedi-2, induced a significantly greater Ca2+ influx in PCs than in ICs. Using patch clamp analysis, we recorded a Yoda-1-activated nonselective channel with 18.6 ± 0.7 pS conductance on both apical and basolateral membranes. Piezo1 activity in PCs but not ICs was stimulated by short-term diuresis (injections of furosemide) and reduced by antidiuresis (water restriction for 24 h). However, prolonged stimulation of flow by high K+ diet decreased Yoda-1-dependent Ca2+ influx without changes in Piezo1 levels. Water supplementation with NH4Cl to induce metabolic acidosis stimulated Piezo1 activity in ICs but not in PCs. Overall, our results demonstrate functional Piezo1 expression in collecting duct PCs (more) and ICs (less) on both apical and basolateral sides. We also show that acute changes in fluid flow regulate Piezo1-mediated [Ca2+]i influx in PCs, whereas channel activity in ICs responds to systemic acid-base stimuli.
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Affiliation(s)
- Kyrylo Pyrshev
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center at Houston
| | - Anna Atamanchuk-Stavniichuk
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center at Houston
| | - Mariya Kordysh
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center at Houston
| | - Oleg Zaika
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center at Houston
| | - Viktor N Tomilin
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center at Houston
| | - Oleh Pochynyuk
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center at Houston.
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van Megen WH, Canki E, Wagenaar VHA, van Waes CRMM, Peters DJM, Van Asbeck-Van der Wijst J, Hoenderop JGJ. Fluid shear stress stimulates ATP release without regulating purinergic gene expression in the renal inner medullary collecting duct. FASEB J 2023; 37:e23232. [PMID: 37819258 DOI: 10.1096/fj.202301434r] [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: 07/14/2023] [Revised: 09/14/2023] [Accepted: 09/19/2023] [Indexed: 10/13/2023]
Abstract
In the kidney, the flow rate of the pro-urine through the renal tubules is highly variable. The tubular epithelial cells sense these variations in pro-urinary flow rate in order to regulate various physiological processes, including electrolyte reabsorption. One of the mechanosensitive pathways activated by flow is the release of ATP, which can then act as a autocrine or paracrine factor. Increased ATP release is observed in various kidney diseases, among others autosomal dominant polycystic kidney disease (ADPKD). However, the mechanisms underlying flow-induced ATP release in the collecting duct, especially in the inner medullary collecting duct, remain understudied. Using inner medullary collecting duct 3 (IMCD3) cells in a microfluidic setup, we show here that administration of a high flow rate for 1 min results in an increased ATP release compared to a lower flow rate. Although the ATP release channel pannexin-1 contributed to flow-induced ATP release in Pkd1-/- IMCD3 cells, it did not in wildtype IMCD3 cells. In addition, flow application increased the expression of the putative ATP release channel connexin-30.3 (CX30.3) in wildtype and Pkd1-/- IMCD3 cells. However, CX30.3 knockout IMCD3 cells exhibited a similar flow-induced ATP release as wildtype IMCD3 cells, suggesting that CX30.3 does not drive flow-induced ATP release in wildtype IMDC3 cells. Collectively, our results show differential mechanisms underlying flow-induced ATP release in wildtype and Pkd1-/- IMCD3 cells and further strengthen the link between ADPKD and pannexin-1-dependent ATP release.
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Affiliation(s)
- Wouter H van Megen
- Department of Medical Biosciences, Radboudumc, Nijmegen, The Netherlands
| | - Esra Canki
- Department of Medical Biosciences, Radboudumc, Nijmegen, The Netherlands
| | - Vera H A Wagenaar
- Department of Medical Biosciences, Radboudumc, Nijmegen, The Netherlands
| | | | - Dorien J M Peters
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands
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Koulouridis I, Koulouridis E. The Integral Role of Chloride & With-No-Lysine Kinases in Cell Volume Regulation & Hypertension. Int J Nephrol Renovasc Dis 2023; 16:183-196. [PMID: 37601040 PMCID: PMC10438449 DOI: 10.2147/ijnrd.s417766] [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: 04/18/2023] [Accepted: 07/28/2023] [Indexed: 08/22/2023] Open
Abstract
Chloride anions are the most abundant in humans. For many years, it has been believed that chloride is simply a counterion of all other cations, ensuring the electroneutrality of the extracellular space. Recent data suggests that chloride anions possess a broad spectrum of important activities that regulate vital cellular functions. It is now evident that, apart from its contribution to the electroneutrality of the extracellular space, it acts as an osmole and contributes to extracellular and intracellular volume regulation. Its anionic charge also contributes to the generation of cell membrane potential. The most interesting action of chloride anions is their ability to regulate the activity of with-no-lysine kinases, which in turn regulate the activity of sodium chloride and potassium chloride cotransporters and govern the reabsorption of salt and excretion of potassium by nephron epithelia. Chloride anions seem to play a crucial role in cell functions, such as cell volume regulation, sodium reabsorption in the distal nephron, potassium balance, and sodium sensitivity, which lead to hypertension. All of these functions are accomplished on a molecular level via complicated metabolic pathways, many of which remain poorly defined. We attempted to elucidate some of these pathways in light of recent advances in our knowledge, obtained mainly from experimental studies.
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Liu T, Li Y, Wang D, Stauber T, Zhao J. Trends in volume-regulated anion channel (VRAC) research: visualization and bibliometric analysis from 2014 to 2022. Front Pharmacol 2023; 14:1234885. [PMID: 37538172 PMCID: PMC10394876 DOI: 10.3389/fphar.2023.1234885] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Accepted: 07/10/2023] [Indexed: 08/05/2023] Open
Abstract
Objective: In this study, we utilized bibliometric methods to assess the worldwide scientific output and identify hotspots related to the research on the volume-regulated anion channel (VRAC) from 2014 to 2022. Methods: From Web of Science, we obtained studies related to VRAC published from 2014 to 2022. To analyzed the data, we utilized VOSviewer, a tool for visualizing network, to create networks based on the collaboration between countries, institutions, and authors. Additionally, we performed an analysis of journal co-citation, document citation, and co-occurrence of keywords. Furthermore, we employed CiteSpace (6.1. R6 Advanced) to analyzed keywords and co-cited references with the strongest burst. Results: The final analysis included a total of 278 related articles and reviews, covering the period from 2014 to 2022. The United States emerged as the leading country contributing to this field, while the University of Copenhagen stood out as the most prominent institution. The author with most publications and most citations was Thomas J. Jentsch. Among the cited references, the article by Voss et al. published in Science (2014) gained significant attention for its identification of LRRC8 heteromers as a crucial component of the volume-regulated anion channel VRAC. Pflügers Archiv European Journal of Physiology and Journal of Physiology-London were the leading journals in terms of the quantity of associated articles and citations. Through the analysis of keyword co-occurrence, it was discovered that VRAC is involved in various physiological processes including cell growth, migration, apoptosis, swelling, and myogenesis, as well as anion and organic osmolyte transport including chloride, taurine, glutamate and ATP. VRAC is also associated with related ion channels such as TMEM16A, TMEM16F, pannexin, and CFTR, and associated with various diseases including epilepsy, leukodystrophy, atherosclerosis, hypertension, cerebral edema, stroke, and different types of cancer including gastric cancer, glioblastoma and hepatocellular carcinoma. Furthermore, VRAC is involved in anti-tumor drug resistance by regulating the uptake of platinum-based drugs and temozolomide. Additionally, VRAC has been studied in the context of pharmacology involving DCPIB and flavonoids. Conclusion: The aim of this bibliometric analysis is to provide an overall perspective for research on VRAC. VRAC has become a topic of increasing interest, and our analysis shows that it continues to be a prominent area. This study offers insights into the investigation of VRAC channel and may guide researchers in identifying new directions for future research.
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Affiliation(s)
- Tianbao Liu
- Key Laboratory of Endocrine Glucose & Lipids Metabolism and Brain Aging, Ministry of Education, Department of Endocrinology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, Shandong, China
- Shandong Key Laboratory of Endocrinology and Lipid Metabolism, Jinan, Shandong, China
- Shandong Institute of Endocrine and Metabolic Disease, Jinan, Shandong, China
| | - Yin Li
- Department of Oncology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Shandong Provincial Hospital, Jinan, Shandong, China
| | - Dawei Wang
- Key Laboratory of Endocrine Glucose & Lipids Metabolism and Brain Aging, Ministry of Education, Department of Endocrinology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, Shandong, China
- Shandong Key Laboratory of Endocrinology and Lipid Metabolism, Jinan, Shandong, China
- Shandong Institute of Endocrine and Metabolic Disease, Jinan, Shandong, China
- Department of Endocrinology, Shandong Provincial Hospital, Shandong University, Jinan, Shandong, China
| | - Tobias Stauber
- Institute for Molecular Medicine, MSH Medical School Hamburg, Hamburg, Germany
| | - Jiajun Zhao
- Key Laboratory of Endocrine Glucose & Lipids Metabolism and Brain Aging, Ministry of Education, Department of Endocrinology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, Shandong, China
- Shandong Key Laboratory of Endocrinology and Lipid Metabolism, Jinan, Shandong, China
- Shandong Institute of Endocrine and Metabolic Disease, Jinan, Shandong, China
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9
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Modus operandi of ClC-K2 Cl - Channel in the Collecting Duct Intercalated Cells. Biomolecules 2023; 13:biom13010177. [PMID: 36671562 PMCID: PMC9855527 DOI: 10.3390/biom13010177] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Revised: 01/10/2023] [Accepted: 01/13/2023] [Indexed: 01/18/2023] Open
Abstract
The renal collecting duct is known to play a critical role in many physiological processes, including systemic water-electrolyte homeostasis, acid-base balance, and the salt sensitivity of blood pressure. ClC-K2 (ClC-Kb in humans) is a Cl--permeable channel expressed on the basolateral membrane of several segments of the renal tubule, including the collecting duct intercalated cells. ClC-Kb mutations are causative for Bartters' syndrome type 3 manifested as hypotension, urinary salt wasting, and metabolic alkalosis. However, little is known about the significance of the channel in the collecting duct with respect to the normal physiology and pathology of Bartters' syndrome. In this review, we summarize the available experimental evidence about the signaling determinants of ClC-K2 function and the regulation by systemic and local factors as well as critically discuss the recent advances in understanding the collecting-duct-specific roles of ClC-K2 in adaptations to changes in dietary Cl- intake and maintaining systemic acid-base homeostasis.
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Ghouli MR, Fiacco TA, Binder DK. Structure-function relationships of the LRRC8 subunits and subdomains of the volume-regulated anion channel (VRAC). Front Cell Neurosci 2022; 16:962714. [PMID: 36035259 PMCID: PMC9399500 DOI: 10.3389/fncel.2022.962714] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Accepted: 07/18/2022] [Indexed: 11/19/2022] Open
Abstract
Volume Regulated Anion Channels (VRAC) are critical contributors to cell volume homeostasis and are expressed ubiquitously in all vertebrate cells. VRAC sense increases in cell volume, and act to return cells to baseline volume in a process known as regulatory volume decrease (RVD) through the efflux of anions and organic osmolytes. This review will highlight seminal studies that elucidated the role of VRAC in RVD, their characteristics as a function of subunit specificity, and their clinical relevance in physiology and pathology. VRAC are also known as volume-sensitive outward rectifiers (VSOR) and volume-sensitive organic osmolyte/anion channels (VSOAC). In this review, the term VRAC will be used to refer to this family of channels.
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Affiliation(s)
- Manolia R. Ghouli
- Division of Biomedical Sciences, School of Medicine, University of California–Riverside, Riverside, CA, United States
| | - Todd A. Fiacco
- Department of Cell Biology and Neuroscience, Center for Glial-Neuronal Interactions, University of California–Riverside, Riverside, CA, United States
| | - Devin K. Binder
- Division of Biomedical Sciences, School of Medicine, University of California–Riverside, Riverside, CA, United States
- *Correspondence: Devin K. Binder
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Pochynyuk O, Palygin O. Unfulfilled Expectations Open New Horizons: What Have We Learned about Volume-Regulated Anion Channels in the Kidney? J Am Soc Nephrol 2022; 33:1437-1439. [PMID: 35840173 PMCID: PMC9342627 DOI: 10.1681/asn.2022050588] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Affiliation(s)
- Oleh Pochynyuk
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center at Houston, Houston, Texas
| | - Oleg Palygin
- Department of Medicine, Medical University of South Carolina, Charleston, South Carolina
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