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Untiet V. Astrocytic chloride regulates brain function in health and disease. Cell Calcium 2024; 118:102855. [PMID: 38364706 DOI: 10.1016/j.ceca.2024.102855] [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: 12/18/2023] [Revised: 02/02/2024] [Accepted: 02/06/2024] [Indexed: 02/18/2024]
Abstract
Chloride ions (Cl-) play a pivotal role in synaptic inhibition in the central nervous system, primarily mediated through ionotropic mechanisms. A recent breakthrough emphathizes the significant influence of astrocytic intracellular chloride concentration ([Cl-]i) regulation, a field still in its early stages of exploration. Typically, the [Cl-]i in most animal cells is maintained at lower levels than the extracellular chloride [Cl-]o, a critical balance to prevent cell swelling due to osmotic pressure. Various Cl- transporters are expressed differently across cell types, fine-tuning the [Cl-]i, while Cl- gradients are utilised by several families of Cl- channels. Although the passive distribution of ions within cells is governed by basic biophysical principles, astrocytes actively expend energy to sustain [Cl-]i at much higher levels than those achieved passively, and much higher than neuronal [Cl-]i. Beyond the role in volume regulation, astrocytic [Cl-]i is dynamically linked to brain states and influences neuronal signalling in actively behaving animals. As a vital component of brain function, astrocytic [Cl-]i also plays a role in the development of disorders where inhibitory transmission is disrupted. This review synthesises the latest insights into astrocytic [Cl-]i, elucidating its role in modulating brain function and its implications in various pathophysiological conditions.
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Affiliation(s)
- Verena Untiet
- Division of Glial Disease and Therapeutics, Center for Translational Neuromedicine, University of Copenhagen, 2200 Copenhagen, Denmark.
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2
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Xu M, Neelands T, Powers AS, Liu Y, Miller SD, Pintilie GD, Bois JD, Dror RO, Chiu W, Maduke M. CryoEM structures of the human CLC-2 voltage-gated chloride channel reveal a ball-and-chain gating mechanism. eLife 2024; 12:RP90648. [PMID: 38345841 PMCID: PMC10942593 DOI: 10.7554/elife.90648] [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] [Indexed: 02/15/2024] Open
Abstract
CLC-2 is a voltage-gated chloride channel that contributes to electrical excitability and ion homeostasis in many different tissues. Among the nine mammalian CLC homologs, CLC-2 is uniquely activated by hyperpolarization, rather than depolarization, of the plasma membrane. The molecular basis for the divergence in polarity of voltage gating among closely related homologs has been a long-standing mystery, in part because few CLC channel structures are available. Here, we report cryoEM structures of human CLC-2 at 2.46 - 2.76 Å, in the presence and absence of the selective inhibitor AK-42. AK-42 binds within the extracellular entryway of the Cl--permeation pathway, occupying a pocket previously proposed through computational docking studies. In the apo structure, we observed two distinct conformations involving rotation of one of the cytoplasmic C-terminal domains (CTDs). In the absence of CTD rotation, an intracellular N-terminal 15-residue hairpin peptide nestles against the TM domain to physically occlude the Cl--permeation pathway. This peptide is highly conserved among species variants of CLC-2 but is not present in other CLC homologs. Previous studies suggested that the N-terminal domain of CLC-2 influences channel properties via a "ball-and-chain" gating mechanism, but conflicting data cast doubt on such a mechanism, and thus the structure of the N-terminal domain and its interaction with the channel has been uncertain. Through electrophysiological studies of an N-terminal deletion mutant lacking the 15-residue hairpin peptide, we support a model in which the N-terminal hairpin of CLC-2 stabilizes a closed state of the channel by blocking the cytoplasmic Cl--permeation pathway.
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Affiliation(s)
- Mengyuan Xu
- Department of Molecular and Cellular Physiology, Stanford UniversityStanfordUnited States
| | - Torben Neelands
- Department of Molecular and Cellular Physiology, Stanford UniversityStanfordUnited States
| | - Alexander S Powers
- Department of Chemistry, Stanford UniversityStanfordUnited States
- Department of Computer Science, Stanford UniversityStanfordUnited States
- Department of Structural Biology, Stanford UniversityStanfordUnited States
- Institute for Computational and Mathematical Engineering, Stanford UniversityStanfordUnited States
| | - Yan Liu
- Division of CryoEM and Bioimaging, SSRL, SLAC National Accelerator Laboratory, Stanford UniversityStanfordUnited States
| | - Steven D Miller
- Department of Chemistry, Stanford UniversityStanfordUnited States
| | - Grigore D Pintilie
- Department of Bioengineering and Department of Microbiology and Immunology, Stanford UniversityStanfordUnited States
| | - J Du Bois
- Department of Chemistry, Stanford UniversityStanfordUnited States
| | - Ron O Dror
- Department of Molecular and Cellular Physiology, Stanford UniversityStanfordUnited States
- Department of Computer Science, Stanford UniversityStanfordUnited States
- Department of Structural Biology, Stanford UniversityStanfordUnited States
- Institute for Computational and Mathematical Engineering, Stanford UniversityStanfordUnited States
| | - Wah Chiu
- Division of CryoEM and Bioimaging, SSRL, SLAC National Accelerator Laboratory, Stanford UniversityStanfordUnited States
- Department of Bioengineering and Department of Microbiology and Immunology, Stanford UniversityStanfordUnited States
| | - Merritt Maduke
- Department of Molecular and Cellular Physiology, Stanford UniversityStanfordUnited States
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Stölting G, Scholl UI. Adrenal Anion Channels: New Roles in Zona Glomerulosa Physiology and in the Pathophysiology of Primary Aldosteronism. Handb Exp Pharmacol 2024; 283:59-79. [PMID: 37495852 DOI: 10.1007/164_2023_680] [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: 07/28/2023]
Abstract
The mineralocorticoid aldosterone is produced in the zona glomerulosa of the adrenal cortex. Its synthesis is regulated by the serum concentrations of the peptide hormone angiotensin II and potassium. The primary role of aldosterone is to control blood volume and electrolytes. The autonomous production of aldosterone (primary aldosteronism, PA) is considered the most frequent cause of secondary hypertension. Aldosterone-producing adenomas and (micro-)nodules are frequent causes of PA and often carry somatic mutations in ion channels and transporters. Rare familial forms of PA are due to germline mutations. Both somatic and germline mutations in the chloride channel gene CLCN2, encoding ClC-2, have been identified in PA. Clinical findings and results from cell culture and animal models have advanced our knowledge about the role of anions in PA. The zona glomerulosa of the adrenal gland has now been firmly established as a tissue in which anions play a significant role for signaling. In this overview, we aim to summarize the current knowledge and highlight novel concepts as well as open questions.
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Affiliation(s)
- Gabriel Stölting
- Center of Functional Genomics, Berlin Institute of Health at Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Ute I Scholl
- Center of Functional Genomics, Berlin Institute of Health at Charité - Universitätsmedizin Berlin, Berlin, Germany.
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4
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Kwon HC, Fairclough RH, Chen TY. Biophysical and Pharmacological Insights to CLC Chloride Channels. Handb Exp Pharmacol 2024; 283:1-34. [PMID: 35768555 DOI: 10.1007/164_2022_594] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The CLC family encompasses two functional categories of transmembrane proteins: chloride conducting channels and proton-chloride antiporters. All members in this chloride channel/transporter family consist of two identical protein subunits, and each subunit forms an independent ion-transport pathway, a structural architecture known as "double barrel." These CLC proteins serve biological functions ranging from membrane excitability and cell volume regulation to acidification of endosomes. Despite their ubiquitous expression, physiological significance, and resolved molecular structures of some of the family members, the mechanisms governing these molecules' biophysical functions are still not completely settled. However, a series of functional and structural studies have brought insights into interesting questions related to these proteins. This chapter explores the functional peculiarities underlying CLC channels aided by information observed from the chloride-proton antiporters in the CLC family. The overall structural features of these CLC proteins will be presented, and the biophysical functions will be addressed. Finally, the mechanism of pharmacological agents that interact with CLC channels will also be discussed.
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Affiliation(s)
- Hwoi Chan Kwon
- Center for Neuroscience and Biophysics Graduate Group, University of California, Davis, CA, USA
| | - Robert H Fairclough
- Department of Neurology and the Biophysics Graduate Group, University of California, Davis, CA, USA
| | - Tsung-Yu Chen
- Center for Neuroscience, Department of Neurology, and Biophysics Graduate Group, University of California, Davis, CA, USA.
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5
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Xu M, Neelands T, Powers AS, Liu Y, Miller SD, Pintilie G, Bois JD, Dror RO, Chiu W, Maduke M. CryoEM structures of the human CLC-2 voltage gated chloride channel reveal a ball and chain gating mechanism. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.13.553136. [PMID: 37645939 PMCID: PMC10462068 DOI: 10.1101/2023.08.13.553136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/31/2023]
Abstract
CLC-2 is a voltage-gated chloride channel that contributes to electrical excitability and ion homeostasis in many different mammalian tissues and cell types. Among the nine mammalian CLC homologs, CLC-2 is uniquely activated by hyperpolarization, rather than depolarization, of the plasma membrane. The molecular basis for the divergence in polarity of voltage gating mechanisms among closely related CLC homologs has been a long-standing mystery, in part because few CLC channel structures are available, and those that exist exhibit high conformational similarity. Here, we report cryoEM structures of human CLC-2 at 2.46 - 2.76 Å, in the presence and absence of the potent and selective inhibitor AK-42. AK-42 binds within the extracellular entryway of the Cl--permeation pathway, occupying a pocket previously proposed through computational docking studies. In the apo structure, we observed two distinct apo conformations of CLC-2 involving rotation of one of the cytoplasmic C-terminal domains (CTDs). In the absence of CTD rotation, an intracellular N-terminal 15-residue hairpin peptide nestles against the TM domain to physically occlude the Cl--permeation pathway from the intracellular side. This peptide is highly conserved among species variants of CLC-2 but is not present in any other CLC homologs. Previous studies suggested that the N-terminal domain of CLC-2 influences channel properties via a "ball-and-chain" gating mechanism, but conflicting data cast doubt on such a mechanism, and thus the structure of the N-terminal domain and its interaction with the channel has been uncertain. Through electrophysiological studies of an N-terminal deletion mutant lacking the 15-residue hairpin peptide, we show that loss of this short sequence increases the magnitude and decreases the rectification of CLC-2 currents expressed in mammalian cells. Furthermore, we show that with repetitive hyperpolarization WT CLC-2 currents increase in resemblance to the hairpin-deleted CLC-2 currents. These functional results combined with our structural data support a model in which the N-terminal hairpin of CLC-2 stabilizes a closed state of the channel by blocking the cytoplasmic Cl--permeation pathway.
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Affiliation(s)
- Mengyuan Xu
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA 94305
| | - Torben Neelands
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA 94305
| | - Alexander S. Powers
- Department of Chemistry, Stanford University, Stanford, CA 94305
- Department of Computer Science, Stanford University, Stanford, CA 94305
- Department of Structural Biology, Stanford University, Stanford, CA 94305
- Institute for Computational and Mathematical Engineering, Stanford University, Stanford, CA 94305
| | - Yan Liu
- Division of CryoEM and Bioimaging, SSRL, SLAC National Accelerator Laboratory, Stanford University, Menlo Park 94025
| | - Steven D. Miller
- Department of Chemistry, Stanford University, Stanford, CA 94305
| | - Grigore Pintilie
- Department of Bioengineering and Department of Microbiology and Immunology, Stanford University, Stanford, 94305
| | - J. Du Bois
- Department of Chemistry, Stanford University, Stanford, CA 94305
| | - Ron O. Dror
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA 94305
- Department of Computer Science, Stanford University, Stanford, CA 94305
- Department of Structural Biology, Stanford University, Stanford, CA 94305
- Institute for Computational and Mathematical Engineering, Stanford University, Stanford, CA 94305
| | - Wah Chiu
- Division of CryoEM and Bioimaging, SSRL, SLAC National Accelerator Laboratory, Stanford University, Menlo Park 94025
- Department of Bioengineering and Department of Microbiology and Immunology, Stanford University, Stanford, 94305
| | - Merritt Maduke
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA 94305
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6
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Ma T, Wang L, Chai A, Liu C, Cui W, Yuan S, Wing Ngor Au S, Sun L, Zhang X, Zhang Z, Lu J, Gao Y, Wang P, Li Z, Liang Y, Vogel H, Wang YT, Wang D, Yan K, Zhang H. Cryo-EM structures of ClC-2 chloride channel reveal the blocking mechanism of its specific inhibitor AK-42. Nat Commun 2023; 14:3424. [PMID: 37296152 PMCID: PMC10256776 DOI: 10.1038/s41467-023-39218-6] [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: 06/08/2022] [Accepted: 06/02/2023] [Indexed: 06/12/2023] Open
Abstract
ClC-2 transports chloride ions across plasma membranes and plays critical roles in cellular homeostasis. Its dysfunction is involved in diseases including leukodystrophy and primary aldosteronism. AK-42 was recently reported as a specific inhibitor of ClC-2. However, experimental structures are still missing to decipher its inhibition mechanism. Here, we present cryo-EM structures of apo ClC-2 and its complex with AK-42, both at 3.5 Å resolution. Residues S162, E205 and Y553 are involved in chloride binding and contribute to the ion selectivity. The side-chain of the gating glutamate E205 occupies the putative central chloride-binding site, indicating that our structure represents a closed state. Structural analysis, molecular dynamics and electrophysiological recordings identify key residues to interact with AK-42. Several AK-42 interacting residues are present in ClC-2 but not in other ClCs, providing a possible explanation for AK-42 specificity. Taken together, our results experimentally reveal the potential inhibition mechanism of ClC-2 inhibitor AK-42.
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Grants
- National Natural Science Foundation of China (National Science Foundation of China)
- National Science and Technology Innovation 2030 Major Program (No. 2022ZD0211900)
- the Science and Technology Innovation Committee of Shenzhen(No. JCYJ20200109150700942), the Key-Area Research and Development Program of Guangdong Province (2019B030335001), the Shenzhen Fund for Guangdong Provincial High Level Clinical Key Specialties (No. SZGSP013), and the Shenzhen Key Medical Discipline Construction Fund (No. SZXK042)
- The Shenzhen Key Laboratory of Computer Aided Drug Discovery, Advanced Technology, Chinese Academy of Sciences, Shenzhen, Guangdong, 518055, China, Funding number: ZDSYS20201230165400001. The Chinese Academy of Science President’s International Fellowship Initiative (PIFI) (No. 2020FSB0003), Guangdong Retired Expert (granted by Guangdong Province), National Overseas High Level Talent Introduction Plan-Foreign Expert from Organization Department of the CPC Central Committee (1000 talent project), Shenzhen Pengcheng Scientist, NSFC-SNSF Funding (No. 32161133022), AlphaMol & SIAT Joint Laboratory, Shenzhen Government Top-talent Working Funding and Guangdong Province Academician Work Funding.
- NSFC-Guangdong Joint Fund-U20A6005, Shenzhen Key Laboratory of Translational Research for Brain Diseases (ZDSYS20200828154800001)
- Shenzhen Science and Technology Program (No. JCYJ20220530115214033 and No. KQTD20210811090115021)
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Affiliation(s)
- Tao Ma
- Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, 518055, Shenzhen, China
- Department of Biomedical Engineering, Southern University of Science and Technology, 518055, Shenzhen, China
| | - Lei Wang
- School of Life Sciences, Southern University of Science and Technology, 518055, Shenzhen, China
| | - Anping Chai
- Shenzhen Key Laboratory of Translational Research for Brain Diseases, The Brain Cognition and Brain Disease Institute, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
- Shenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research Institutions, 518055, Shenzhen, Guangdong, China
| | - Chao Liu
- Department of Biomedical Engineering, Southern University of Science and Technology, 518055, Shenzhen, China
| | - Wenqiang Cui
- Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, 518055, Shenzhen, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Shuguang Yuan
- Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, 518055, Shenzhen, China
| | - Shannon Wing Ngor Au
- School of Life Sciences, The Chinese University of Hong Kong, Shatin, Hong Kong, China
| | - Liang Sun
- Shenzhen Shuli Tech Co., Ltd, 518126, Shenzhen, Guangdong, China
| | - Xiaokang Zhang
- Shenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research Institutions, 518055, Shenzhen, Guangdong, China
- Interdisciplinary Center for Brain Information, The Brain Cognition and Brain Disease Institute, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, 518055, Shenzhen, Guangdong, China
- Faculty of Life and Health Sciences, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, 518055, Shenzhen, Guangdong, China
| | - Zhenzhen Zhang
- Department of Biomedical Engineering, Southern University of Science and Technology, 518055, Shenzhen, China
| | - Jianping Lu
- Department of Child and Adolescent Psychiatry, Shenzhen Kangning Hospital, Shenzhen Mental Health Center, Shenzhen, 518020, China
| | - Yuanzhu Gao
- Cryo-EM Facility Center, Southern University of Science and Technology, 518055, Shenzhen, Guangdong, China
| | - Peiyi Wang
- Cryo-EM Facility Center, Southern University of Science and Technology, 518055, Shenzhen, Guangdong, China
| | - Zhifang Li
- Department of Biomedical Engineering, Southern University of Science and Technology, 518055, Shenzhen, China
| | - Yujie Liang
- Department of Child and Adolescent Psychiatry, Shenzhen Kangning Hospital, Shenzhen Mental Health Center, Shenzhen, 518020, China
| | - Horst Vogel
- Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, 518055, Shenzhen, China.
- Institut des Sciences et Ingénierie Chimiques (ISIC), Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland.
| | - Yu Tian Wang
- Shenzhen Key Laboratory of Translational Research for Brain Diseases, The Brain Cognition and Brain Disease Institute, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China.
- Faculty of Life and Health Sciences, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, 518055, Shenzhen, Guangdong, China.
| | - Daping Wang
- Department of Biomedical Engineering, Southern University of Science and Technology, 518055, Shenzhen, China.
- Department of Orthopedics, Shenzhen Intelligent Orthopaedics and Biomedical Innovation Platform, Guangdong Provincial Research Center for Artificial Intelligence and Digital Orthopedic Technology, Shenzhen Second People's Hospital, The First Affiliated Hospital of Shenzhen University, 518000, Shenzhen, China.
| | - Kaige Yan
- School of Life Sciences, Southern University of Science and Technology, 518055, Shenzhen, China.
| | - Huawei Zhang
- Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, 518055, Shenzhen, China.
- Department of Biomedical Engineering, Southern University of Science and Technology, 518055, Shenzhen, China.
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Xu P, Chen Z, Ma J, Shan Y, Wang Y, Xie B, Zheng D, Guo F, Song X, Gao G, Ye K, Liu Y, Pan G, Jiang B, Peng F, Zhong X. Biallelic CLCN2 mutations cause retinal degeneration by impairing retinal pigment epithelium phagocytosis and chloride channel function. Hum Genet 2023; 142:577-593. [PMID: 36964785 DOI: 10.1007/s00439-023-02531-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Accepted: 02/06/2023] [Indexed: 03/26/2023]
Abstract
CLCN2 encodes a two-pore homodimeric chloride channel protein (CLC-2) that is widely expressed in human tissues. The association between Clcn2 and the retina is well-established in mice, as loss-of-function of CLC-2 can cause retinopathy in mice; however, the ocular phenotypes caused by CLCN2 mutations in humans and the underlying mechanisms remain unclear. The present study aimed to define the ocular features and reveal the pathogenic mechanisms of CLCN2 variants associated with retinal degeneration in humans using an in vitro overexpression system, as well as patient-induced pluripotent stem cell (iPSC)-derived retinal pigment epithelium (RPE) cells and retinal organoids (ROs). A patient carrying the homozygous c.2257C > T (p.R753X) nonsense CLCN2 mutation was followed up for > 6 years. Ocular features were comprehensively characterized with multimodality imaging and functional examination. The patient presented with severe bilateral retinal degeneration with loss of photoreceptor and RPE. In vitro, mutant CLC-2 maintained the correct subcellular localization, but with reduced channel function compared to wild-type CLC-2 in HEK293T cells. Additionally, patient iPSC-derived RPE cells carrying the CLCN2 mutation exhibited dysfunctional ClC-2 chloride channels and outer segment phagocytosis. Notably, these functions were rescued following the repair of the CLCN2 mutation using the CRISPR-Cas9 system. However, this variant did not cause significant photoreceptor degeneration in patient-derived ROs, indicating that dysfunctional RPE is likely the primary cause of biallelic CLCN2 variant-mediated retinopathy. This study is the first to establish the confirmatory ocular features of human CLCN2-related retinal degeneration, and reveal a pathogenic mechanism associated with biallelic CLCN2 variants, providing new insights into the cause of inherited retinal dystrophies.
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Affiliation(s)
- Ping Xu
- State Key Laboratory of Ophthalmology, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, 510060, China
| | - Zhuolin Chen
- Department of Neurology, The Third Affiliated Hospital of Sun Yat-Sen University, Guangzhou, 510630, China
| | - Jianchi Ma
- Guangdong Province Key Laboratory of Brain Function and Disease, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, 510080, China
| | - Yongli Shan
- CAS Key Laboratory of Regenerative Biology, Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, South China, Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, China
| | - Yuan Wang
- State Key Laboratory of Ophthalmology, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, 510060, China
| | - Bingbing Xie
- State Key Laboratory of Ophthalmology, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, 510060, China
| | - Dandan Zheng
- State Key Laboratory of Ophthalmology, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, 510060, China
| | - Fuying Guo
- State Key Laboratory of Ophthalmology, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, 510060, China
| | - Xiaojing Song
- State Key Laboratory of Ophthalmology, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, 510060, China
| | - Guanjie Gao
- State Key Laboratory of Ophthalmology, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, 510060, China
| | - Ke Ye
- State Key Laboratory of Ophthalmology, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, 510060, China
| | - Yizhi Liu
- State Key Laboratory of Ophthalmology, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, 510060, China
| | - Guangjin Pan
- CAS Key Laboratory of Regenerative Biology, Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, South China, Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, China
| | - Bin Jiang
- Guangdong Province Key Laboratory of Brain Function and Disease, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, 510080, China
| | - Fuhua Peng
- Department of Neurology, The Third Affiliated Hospital of Sun Yat-Sen University, Guangzhou, 510630, China.
| | - Xiufeng Zhong
- State Key Laboratory of Ophthalmology, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, 510060, China.
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8
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Sinha M, Zabini D, Guntur D, Nagaraj C, Enyedi P, Olschewski H, Kuebler WM, Olschewski A. Chloride channels in the lung: Challenges and perspectives for viral infections, pulmonary arterial hypertension, and cystic fibrosis. Pharmacol Ther 2022; 237:108249. [DOI: 10.1016/j.pharmthera.2022.108249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Revised: 07/06/2022] [Accepted: 07/11/2022] [Indexed: 10/16/2022]
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9
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Ochoa-de la Paz LD, Gulias-Cañizo R. Glia as a key factor in cell volume regulation processes of the central nervous system. Front Cell Neurosci 2022; 16:967496. [PMID: 36090789 PMCID: PMC9453262 DOI: 10.3389/fncel.2022.967496] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Accepted: 08/03/2022] [Indexed: 11/23/2022] Open
Abstract
Brain edema is a pathological condition with potentially fatal consequences, related to cerebral injuries such as ischemia, chronic renal failure, uremia, and diabetes, among others. Under these pathological states, the cell volume control processes are fully compromised, because brain cells are unable to regulate the movement of water, mainly regulated by osmotic gradients. The processes involved in cell volume regulation are homeostatic mechanisms that depend on the mobilization of osmolytes (ions, organic molecules, and polyols) in the necessary direction to counteract changes in osmolyte concentration in response to water movement. The expression and coordinated function of proteins related to the cell volume regulation process, such as water channels, ion channels, and other cotransport systems in the glial cells, and considering the glial cell proportion compared to neuronal cells, leads to consider the astroglial network the main regulatory unit for water homeostasis in the central nervous system (CNS). In the last decade, several studies highlighted the pivotal role of glia in the cell volume regulation process and water homeostasis in the brain, including the retina; any malfunction of this astroglial network generates a lack of the ability to regulate the osmotic changes and water movements and consequently exacerbates the pathological condition.
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Affiliation(s)
- Lenin David Ochoa-de la Paz
- Departamento de Bioquímica, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico
- Asociación para Evitar la Ceguera en México (APEC), Unidad de Investigación APEC-UNAM, Mexico
- *Correspondence: Lenin David Ochoa-de la Paz
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10
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Oak AA, Chu T, Yottasan P, Chhetri PD, Zhu J, Du Bois J, Cil O. Lubiprostone is non-selective activator of cAMP-gated ion channels and Clc-2 has a minor role in its prosecretory effect in intestinal epithelial cells. Mol Pharmacol 2022; 102:MOLPHARM-AR-2022-000542. [PMID: 35680165 PMCID: PMC9341254 DOI: 10.1124/molpharm.122.000542] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2022] [Revised: 05/21/2022] [Accepted: 05/27/2022] [Indexed: 12/14/2022] Open
Abstract
Loss of prosecretory Cl- channel CFTR activity is considered as the key cause of gastrointestinal disorders in cystic fibrosis including constipation and meconium ileus. Clc-2 is proposed as an alternative Cl- channel in intestinal epithelia that can compensate for CFTR loss-of-function. Lubiprostone is an FDA-approved drug with Clc-2 activation as its presumed mechanism of action. However, relative contribution of Clc-2 in intestinal Cl- secretion and the mechanism of action of lubiprostone remain controversial due to lack of selective Clc-2 inhibitors. Using recently identified selective Clc-2 inhibitor AK-42, we characterized the roles of Clc-2 in Cl- secretion in human intestinal epithelial T84 cells. Clc-2 inhibitor AK-42 had minimal (15%) inhibitory effect on secretory short-circuit current (Isc) induced by cAMP agonists, where subsequently applied CFTR inhibitor (CFTRinh-172) caused 2-3 fold greater inhibition. Similarly, AK-42 inhibited lubiprostone-induced secretory Isc by 20%, whereas CFTRinh-172 caused 2-3 fold greater inhibition. In addition to increasing CFTR and Clc-2-mediated apical Cl- conductance, lubiprostone increased basolateral membrane K+ conductance, which was completely reversed by cAMP-activated K+ channel inhibitor BaCl2 All components of lubiprostone-induced secretion (Clc-2, CFTR and K+ channels) were inhibited by ~65% with the extracellular Ca2+-sensing receptor (CaSR) activator cinacalcet that stimulates cAMP hydrolysis. Lastly, EP4 prostaglandin receptor inhibitor GW627368 pretreatment inhibited lubiprostone-induced secretion by 40% without any effect on forskolin response. Our findings suggest that Clc-2 has minor role in cAMP-induced intestinal Cl- secretion; and lubiprostone is not a selective Clc-2 activator, but general activator of cAMP-gated ion channels in human intestinal epithelial cells. Significance Statement Cl- channel Clc-2 activation is the proposed mechanism of action of the FDA-approved constipation drug lubiprostone. Using first-in-class selective Clc-2 inhibitor AK-42, we showed that Clc-2 has minor contribution in intestinal Cl- secretion induced by lubiprostone and cAMP agonists. We also found that lubiprostone is a general activator of cAMP-gated ion channels in human intestinal epithelial cells (via EP4 receptors). Our findings clarify the roles of Clc-2 in intestinal Cl- secretion and elucidate the mechanism of action of approved-drug lubiprostone.
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Affiliation(s)
| | | | | | | | - Jie Zhu
- Stanford University, United States
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11
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Luo Y, Liu X, Li X, Zhong W, Lin J, Chen Q. Identification and validation of a signature involving voltage-gated chloride ion channel genes for prediction of prostate cancer recurrence. Front Endocrinol (Lausanne) 2022; 13:1001634. [PMID: 36246902 PMCID: PMC9561150 DOI: 10.3389/fendo.2022.1001634] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/23/2022] [Accepted: 09/06/2022] [Indexed: 11/26/2022] Open
Abstract
Voltage-gated chloride ion channels (CLCs) are transmembrane proteins that maintain chloride ion homeostasis in various cells. Accumulating studies indicated CLCs were related to cell growth, proliferation, and cell cycle. Nevertheless, the role of CLCs in prostate cancer (PCa) has not been systematically profiled. The purpose of this study was to investigate the expression profiles and biofunctions of CLCs genes, and construct a novel risk signature to predict biochemical recurrence (BCR) of PCa patients. We identified five differentially expressed CLCs genes in our cohort and then constructed a signature composed of CLCN2 and CLCN6 through Lasso-Cox regression analysis in the training cohort from the Cancer Genome Atlas (TCGA). The testing and entire cohorts from TCGA and the GSE21034 from the Gene Expression Omnibus (GEO) were used as internal and independent external validation datasets. This signature could divide PCa patients into the high and low risk groups with different prognoses, was apparently correlated with clinical features, and was an independent excellent prognostic indicator. Enrichment analysis indicated our signature was primarily concentrated in cellular process and metabolic process. The expression patterns of CLCN2 and CLCN6 were detected in our own cohort based immunohistochemistry staining, and we found CLCN2 and CLCN6 were highly expressed in PCa tissues compared with benign tissues and positively associated with higher Gleason score and shorter BCR-free time. Functional experiments revealed that CLCN2 and CLCN6 downregulation inhibited cell proliferation, colony formation, invasion, and migration, but prolonged cell cycle and promoted apoptosis. Furthermore, Seahorse assay showed that silencing CLCN2 or CLCN6 exerted potential inhibitory effects on energy metabolism in PCa. Collectively, our signature could provide a novel and robust strategy for the prognostic evaluation and improve treatment decision making for PCa patients.
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Affiliation(s)
- Yong Luo
- Department of Urology, The Second People’s Hospital of Foshan, Affiliated Foshan Hospital of Southern Medical University, Foshan, China
| | - Xiaopeng Liu
- Department of Science and Teaching, The Second People’s Hospital of Foshan, Affiliated Foshan Hospital of Southern Medical University, Foshan, China
| | - Xiaoxiao Li
- Department of Nursing Administration, the Second People’s Hospital of Foshan, Affiliated Foshan Hospital of Southern Medical University, Foshan, China
| | - Weide Zhong
- Department of Urology, The Second People’s Hospital of Foshan, Affiliated Foshan Hospital of Southern Medical University, Foshan, China
- Department of Urology, Guangdong Key Laboratory of Clinical Molecular Medicine and Diagnostics, Guangzhou First People’s Hospital, School of Medicine, South China University of Technology, Guangzhou, China
- Urology Key Laboratory of Guangdong Province, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou Medical University, Guangzhou, China
- Guangdong Provincial Institute of Nephrology, Nanfang Hospital, Southern Medical University, Guangzhou, China
- State Key Laboratory of Quality Research in Chinese Medicines, Macau University of Science and Technology, Macau, Macau SAR, China
- *Correspondence: Qingbiao Chen, ; Jingbo Lin, ; Weide Zhong,
| | - Jingbo Lin
- Department of Urology, The Second People’s Hospital of Foshan, Affiliated Foshan Hospital of Southern Medical University, Foshan, China
- *Correspondence: Qingbiao Chen, ; Jingbo Lin, ; Weide Zhong,
| | - Qingbiao Chen
- Department of Urology, The Second People’s Hospital of Foshan, Affiliated Foshan Hospital of Southern Medical University, Foshan, China
- *Correspondence: Qingbiao Chen, ; Jingbo Lin, ; Weide Zhong,
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Tang J, Shen X, Yang Y, Yang H, Qi A, Yang S, Qu K, Lan X, Huang B, Chen H. Two Different Copy Number Variations of the CLCN2 Gene in Chinese Cattle and Their Association with Growth Traits. Animals (Basel) 2021; 12:ani12010041. [PMID: 35011147 PMCID: PMC8749635 DOI: 10.3390/ani12010041] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Revised: 12/20/2021] [Accepted: 12/21/2021] [Indexed: 12/12/2022] Open
Abstract
Copy number variation (CNV) can affect gene function and even individual phenotypic traits by changing the transcription and translation level of related genes, and it also plays an important role in species evolution. Chloride voltage-gated channel 2 (CLCN2) encodes a voltage-gated chloride channel (CLC-2), which has a wide organ distribution and is ubiquitously expressed. Based on previous studies, we hypothesize that CLCN2 could be a candidate gene involved in cell volume regulation, transepithelial transport and cell proliferation. This study aimed to explore CNVs in the CLCN2 gene and investigate its association with growth traits in four Chinese cattle breeds (Yunling cattle, Xianan cattle, Qinchuan cattle and Pinan cattle). We identified there are two copy number variation regions (CNV1: 3600 bp, including exon 2-11; CNV2: 4800 bp, including exon 21-22) of the CLCN2 gene. The statistical analysis showed that the CNV1 mutation in the YL cattle population was significantly associated with cannon circumference (p < 0.01). The CNV2 mutation in the XN cattle population had a significant effect on body slanting length, chest girth and body weight (p < 0.05). In the YL cattle, the association analysis of CLCN2 gene CNV1 and CNV2 combination with cannon circumference was significant (p < 0.01). Our results provide evidence that CNV1 and CNV2 in CLCN2 are associated with growth traits in two different cattle populations and could be used as candidate markers for cattle molecular breeding.
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Affiliation(s)
- Jia Tang
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Xianyang 712100, China; (J.T.); (X.S.); (Y.Y.); (H.Y.); (A.Q.); (S.Y.); (X.L.)
| | - Xuemei Shen
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Xianyang 712100, China; (J.T.); (X.S.); (Y.Y.); (H.Y.); (A.Q.); (S.Y.); (X.L.)
| | - Yu Yang
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Xianyang 712100, China; (J.T.); (X.S.); (Y.Y.); (H.Y.); (A.Q.); (S.Y.); (X.L.)
| | - Haiyan Yang
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Xianyang 712100, China; (J.T.); (X.S.); (Y.Y.); (H.Y.); (A.Q.); (S.Y.); (X.L.)
| | - Ao Qi
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Xianyang 712100, China; (J.T.); (X.S.); (Y.Y.); (H.Y.); (A.Q.); (S.Y.); (X.L.)
| | - Shuling Yang
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Xianyang 712100, China; (J.T.); (X.S.); (Y.Y.); (H.Y.); (A.Q.); (S.Y.); (X.L.)
| | - Kaixing Qu
- Academy of Science and Technology, Chuxiong Normal University, Chuxiong 675000, China;
| | - Xianyong Lan
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Xianyang 712100, China; (J.T.); (X.S.); (Y.Y.); (H.Y.); (A.Q.); (S.Y.); (X.L.)
| | - Bizhi Huang
- Yunnan Academy of Grassland and Animal Science, Kunming 650212, China
- Correspondence: (H.C.); (B.H.)
| | - Hong Chen
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Xianyang 712100, China; (J.T.); (X.S.); (Y.Y.); (H.Y.); (A.Q.); (S.Y.); (X.L.)
- College of Animal Science, Xinjiang Agricultural University, Urumqi 830052, China
- Correspondence: (H.C.); (B.H.)
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Pathophysiological role of ion channels and transporters in gastrointestinal mucosal diseases. Cell Mol Life Sci 2021; 78:8109-8125. [PMID: 34778915 PMCID: PMC8629801 DOI: 10.1007/s00018-021-04011-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 09/10/2021] [Accepted: 10/23/2021] [Indexed: 11/13/2022]
Abstract
The incidence of gastrointestinal (GI) mucosal diseases, including various types of gastritis, ulcers, inflammatory bowel disease and GI cancer, is increasing. Therefore, it is necessary to identify new therapeutic targets. Ion channels/transporters are located on cell membranes, and tight junctions (TJs) affect acid–base balance, the mucus layer, permeability, the microbiota and mucosal blood flow, which are essential for maintaining GI mucosal integrity. As ion channel/transporter dysfunction results in various GI mucosal diseases, this review focuses on understanding the contribution of ion channels/transporters to protecting the GI mucosal barrier and the relationship between GI mucosal disease and ion channels/transporters, including Cl−/HCO3− exchangers, Cl− channels, aquaporins, Na+/H+ exchangers, and K+ channels. Here, we provide novel prospects for the treatment of GI mucosal diseases.
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Dynamic expression of homeostatic ion channels in differentiated cortical astrocytes in vitro. Pflugers Arch 2021; 474:243-260. [PMID: 34734327 PMCID: PMC8766406 DOI: 10.1007/s00424-021-02627-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Revised: 09/02/2021] [Accepted: 09/24/2021] [Indexed: 11/16/2022]
Abstract
The capacity of astrocytes to adapt their biochemical and functional features upon physiological and pathological stimuli is a fundamental property at the basis of their ability to regulate the homeostasis of the central nervous system (CNS). It is well known that in primary cultured astrocytes, the expression of plasma membrane ion channels and transporters involved in homeostatic tasks does not closely reflect the pattern observed in vivo. The individuation of culture conditions that promote the expression of the ion channel array found in vivo is crucial when aiming at investigating the mechanisms underlying their dynamics upon various physiological and pathological stimuli. A chemically defined medium containing growth factors and hormones (G5) was previously shown to induce the growth, differentiation, and maturation of primary cultured astrocytes. Here we report that under these culture conditions, rat cortical astrocytes undergo robust morphological changes acquiring a multi-branched phenotype, which develops gradually during the 2-week period of culturing. The shape changes were paralleled by variations in passive membrane properties and background conductance owing to the differential temporal development of inwardly rectifying chloride (Cl−) and potassium (K+) currents. Confocal and immunoblot analyses showed that morphologically differentiated astrocytes displayed a large increase in the expression of the inward rectifier Cl− and K+ channels ClC-2 and Kir4.1, respectively, which are relevant ion channels in vivo. Finally, they exhibited a large diminution of the intermediate filaments glial fibrillary acidic protein (GFAP) and vimentin which are upregulated in reactive astrocytes in vivo. Taken together the data indicate that long-term culturing of cortical astrocytes in this chemical-defined medium promotes a quiescent functional phenotype. This culture model could aid to address the regulation of ion channel expression involved in CNS homeostasis in response to physiological and pathological challenges.
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15
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Hanke-Gogokhia C, Lehmann GL, Benedicto I, de la Fuente-Ortega E, Arshavsky VY, Schreiner R, Rodriguez-Boulan E. Apical CLC-2 in retinal pigment epithelium is crucial for survival of the outer retina. FASEB J 2021; 35:e21689. [PMID: 34085737 PMCID: PMC8252757 DOI: 10.1096/fj.202100349r] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Revised: 04/16/2021] [Accepted: 05/06/2021] [Indexed: 12/15/2022]
Abstract
Knockout of the chloride channel protein 2 (CLC‐2; CLCN2) results in fast progressing blindness in mice. Retinal Pigment Epithelium (RPE) and photoreceptors undergo, in parallel, rapid, and profound morphological changes and degeneration. Immunohistochemistry and electron microscopy of the outer retina and electroretinography of the CLC‐2 KO mouse demonstrated normal morphology at postnatal day 2, followed by drastic changes in RPE and photoreceptor morphology and loss of vision during the first postnatal month. To investigate whether the RPE or the photoreceptors are the primary cause of the degeneration, we injected lentiviruses carrying HA‐tagged CLC‐2 with an RPE‐specific promotor in the subretinal space of CLC‐2‐KO mice at the time of eye opening. As expected, CLC‐2‐HA was expressed exclusively in RPE; strikingly, this procedure rescued the degeneration of both RPE and photoreceptors. Light response in transduced eyes was also recovered. Only a fraction of RPE was transduced with the lentivirus; however, the entire RPE monolayer appears healthy, even the RPE cells not expressing the CLC‐2‐HA. Surprisingly, in contrast with previous physiological observations that postulate that CLC‐2 has a basolateral localization in RPE, our immunofluorescence experiments demonstrated CLC‐2 has an apical distribution, facing the subretinal space and the photoreceptor outer segments. Our findings suggest that CLC‐2 does not play the postulated role in fluid transport at the basolateral membrane. Rather, they suggest that CLC‐2 performs a critical homeostatic role in the subretinal compartment involving a chloride regulatory mechanism that is critical for the survival of both RPE and photoreceptors.
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Affiliation(s)
| | | | - Ignacio Benedicto
- Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain
| | - Erwin de la Fuente-Ortega
- Departamento de Ciencias Biomédicas, Facultad de Medicina, Universidad Católica del Norte, Coquimbo, Chile
| | - Vadim Y Arshavsky
- Department of Ophthalmology, Duke University School of Medicine, Durham, NC, USA
| | - Ryan Schreiner
- Division of Regenerative Medicine, Ansary Stem Cell Institute, Department of Medicine, Weill Cornell Medicine, New York, NY, USA
| | - Enrique Rodriguez-Boulan
- Department of Ophthalmology, Margaret Dyson Vision Research Institute, Weill Cornell Medicine, New York, NY, USA
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16
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De Jesús-Pérez JJ, Méndez-Maldonado GA, López-Romero AE, Esparza-Jasso D, González-Hernández IL, De la Rosa V, Gastélum-Garibaldi R, Sánchez-Rodríguez JE, Arreola J. Electro-steric opening of the CLC-2 chloride channel gate. Sci Rep 2021; 11:13127. [PMID: 34162897 PMCID: PMC8222222 DOI: 10.1038/s41598-021-92247-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Accepted: 06/04/2021] [Indexed: 01/18/2023] Open
Abstract
The widely expressed two-pore homodimeric inward rectifier CLC-2 chloride channel regulates transepithelial chloride transport, extracellular chloride homeostasis, and neuronal excitability. Each pore is independently gated at hyperpolarized voltages by a conserved pore glutamate. Presumably, exiting chloride ions push glutamate outwardly while external protonation stabilizes it. To understand the mechanism of mouse CLC-2 opening we used homology modelling-guided structure-function analysis. Structural modelling suggests that glutamate E213 interacts with tyrosine Y561 to close a pore. Accordingly, Y561A and E213D mutants are activated at less hyperpolarized voltages, re-opened at depolarized voltages, and fast and common gating components are reduced. The double mutant cycle analysis showed that E213 and Y561 are energetically coupled to alter CLC-2 gating. In agreement, the anomalous mole fraction behaviour of the voltage dependence, measured by the voltage to induce half-open probability, was strongly altered in these mutants. Finally, cytosolic acidification or high extracellular chloride concentration, conditions that have little or no effect on WT CLC-2, induced reopening of Y561 mutants at positive voltages presumably by the inward opening of E213. We concluded that the CLC-2 gate is formed by Y561-E213 and that outward permeant anions open the gate by electrostatic and steric interactions.
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Affiliation(s)
- José J De Jesús-Pérez
- Physics Institute, Universidad Autónoma de San Luis Potosí, Ave. Dr. Manuel Nava #6, 78290, San Luis Potosí, SLP, Mexico
| | - G Arlette Méndez-Maldonado
- Departamento de Física, Centro Universitario de Ciencias Exactas e Ingenierías, Universidad de Guadalajara, Blvd. M. García Barragán #1421, 44430, Guadalajara, Jalisco, Mexico
| | - Ana E López-Romero
- Physics Institute, Universidad Autónoma de San Luis Potosí, Ave. Dr. Manuel Nava #6, 78290, San Luis Potosí, SLP, Mexico
| | - David Esparza-Jasso
- Physics Institute, Universidad Autónoma de San Luis Potosí, Ave. Dr. Manuel Nava #6, 78290, San Luis Potosí, SLP, Mexico
| | - Irma L González-Hernández
- Departamento de Física, Centro Universitario de Ciencias Exactas e Ingenierías, Universidad de Guadalajara, Blvd. M. García Barragán #1421, 44430, Guadalajara, Jalisco, Mexico
| | - Víctor De la Rosa
- CONACYT, School of Medicine, Universidad Autónoma de San Luis Potosí, Ave. V. Carranza 2005, Los Filtros, 78290, San Luis Potosí, SLP, Mexico
| | - Roberto Gastélum-Garibaldi
- Departamento de Física, Centro Universitario de Ciencias Exactas e Ingenierías, Universidad de Guadalajara, Blvd. M. García Barragán #1421, 44430, Guadalajara, Jalisco, Mexico
| | - Jorge E Sánchez-Rodríguez
- Departamento de Física, Centro Universitario de Ciencias Exactas e Ingenierías, Universidad de Guadalajara, Blvd. M. García Barragán #1421, 44430, Guadalajara, Jalisco, Mexico
| | - Jorge Arreola
- Physics Institute, Universidad Autónoma de San Luis Potosí, Ave. Dr. Manuel Nava #6, 78290, San Luis Potosí, SLP, Mexico.
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Regulation of ClC-2 Chloride Channel Proteostasis by Molecular Chaperones: Correction of Leukodystrophy-Associated Defect. Int J Mol Sci 2021; 22:ijms22115859. [PMID: 34070744 PMCID: PMC8197790 DOI: 10.3390/ijms22115859] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 05/23/2021] [Accepted: 05/26/2021] [Indexed: 11/16/2022] Open
Abstract
The ClC-2 channel plays a critical role in maintaining ion homeostasis in the brain and the testis. Loss-of-function mutations in the ClC-2-encoding human CLCN2 gene are linked to the white matter disease leukodystrophy. Clcn2-deficient mice display neuronal myelin vacuolation and testicular degeneration. Leukodystrophy-causing ClC-2 mutant channels are associated with anomalous proteostasis manifesting enhanced endoplasmic reticulum (ER)-associated degradation. The molecular nature of the ER quality control system for ClC-2 protein remains elusive. In mouse testicular tissues and Leydig cells, we demonstrated that endogenous ClC-2 co-existed in the same protein complex with the molecular chaperones heat shock protein 90β (Hsp90β) and heat shock cognate protein (Hsc70), as well as the associated co-chaperones Hsp70/Hsp90 organizing protein (HOP), activator of Hsp90 ATPase homolog 1 (Aha1), and FK506-binding protein 8 (FKBP8). Further biochemical analyses revealed that the Hsp90β-Hsc70 chaperone/co-chaperone system promoted mouse and human ClC-2 protein biogenesis. FKBP8 additionally facilitated membrane trafficking of ClC-2 channels. Interestingly, treatment with the Hsp90-targeting small molecule 17-allylamino-17-demethoxygeldanamycin (17-AAG) substantially boosted ClC-2 protein expression. Also, 17-AAG effectively increased both total and cell surface protein levels of leukodystrophy-causing loss-of-function ClC-2 mutant channels. Our findings highlight the therapeutic potential of 17-AAG in correcting anomalous ClC-2 proteostasis associated with leukodystrophy.
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Chen H, Liu Y, Cheng X, Fang S, Sun Y, Yang Z, Zheng W, Ji X, Wu Z. Self‐Assembly of Size‐Controlled
m
‐Pyridine–Urea Oligomers and Their Biomimetic Chloride Ion Channels. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202102174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Hualong Chen
- Beijing Institute of Brain Disorders Laboratory of Brain Disorders Ministry of Science and Technology Collaborative Innovation Center for Brain Disorders Beijing Advanced Innovation Center for Big Data-based Precision Medicine Capital Medical University Beijing 100069 China
| | - Yajing Liu
- School of Pharmaceutical Science Capital Medical University Beijing 100069 China
| | - Xuebo Cheng
- Beijing Institute of Brain Disorders Laboratory of Brain Disorders Ministry of Science and Technology Collaborative Innovation Center for Brain Disorders Beijing Advanced Innovation Center for Big Data-based Precision Medicine Capital Medical University Beijing 100069 China
| | - Senbiao Fang
- School of Computer Science and Engineering Central South University Changsha 410012 China
| | - Yuli Sun
- Beijing Institute of Brain Disorders Laboratory of Brain Disorders Ministry of Science and Technology Collaborative Innovation Center for Brain Disorders Beijing Advanced Innovation Center for Big Data-based Precision Medicine Capital Medical University Beijing 100069 China
| | - Zequn Yang
- Beijing Institute of Brain Disorders Laboratory of Brain Disorders Ministry of Science and Technology Collaborative Innovation Center for Brain Disorders Beijing Advanced Innovation Center for Big Data-based Precision Medicine Capital Medical University Beijing 100069 China
| | - Wei Zheng
- Beijing Institute of Brain Disorders Laboratory of Brain Disorders Ministry of Science and Technology Collaborative Innovation Center for Brain Disorders Beijing Advanced Innovation Center for Big Data-based Precision Medicine Capital Medical University Beijing 100069 China
| | - Xunming Ji
- Beijing Institute of Brain Disorders Laboratory of Brain Disorders Ministry of Science and Technology Collaborative Innovation Center for Brain Disorders Beijing Advanced Innovation Center for Big Data-based Precision Medicine Capital Medical University Beijing 100069 China
- Institute of Hypoxia Medicine Xuanwu Hospital Capital Medical University Beijing 100053 China
| | - Zehui Wu
- Beijing Institute of Brain Disorders Laboratory of Brain Disorders Ministry of Science and Technology Collaborative Innovation Center for Brain Disorders Beijing Advanced Innovation Center for Big Data-based Precision Medicine Capital Medical University Beijing 100069 China
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Chen H, Liu Y, Cheng X, Fang S, Sun Y, Yang Z, Zheng W, Ji X, Wu Z. Self-Assembly of Size-Controlled m-Pyridine-Urea Oligomers and Their Biomimetic Chloride Ion Channels. Angew Chem Int Ed Engl 2021; 60:10833-10841. [PMID: 33624345 DOI: 10.1002/anie.202102174] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Indexed: 01/06/2023]
Abstract
The m-pyridine urea (mPU) oligomer was constructed by using the intramolecular hydrogen bond formed by the pyridine nitrogen atom and the NH of urea and the intermolecular hydrogen bond of the terminal carbonyl group and the NH of urea. Due to the synergistic effect of hydrogen bonds, mPU oligomer folds and exhibits strong self-assembly behaviour. Affected by folding, mPU oligomer generates a twisted plane, and one of its important features is that the carbonyl group of the urea group orientates outwards from the twisted plane, while the NHs tend to direct inward. This feature is beneficial to NH attraction for electron-rich species. Among them, the trimer self-assembles into helical nanotubes, and can efficiently transport chloride ions. This study provides a novel and efficient strategy for constructing self-assembled biomimetic materials for electron-rich species transmission.
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Affiliation(s)
- Hualong Chen
- Beijing Institute of Brain Disorders, Laboratory of Brain Disorders, Ministry of Science and Technology, Collaborative Innovation Center for Brain Disorders, Beijing Advanced Innovation Center for Big Data-based Precision Medicine, Capital Medical University, Beijing, 100069, China
| | - Yajing Liu
- School of Pharmaceutical Science, Capital Medical University, Beijing, 100069, China
| | - Xuebo Cheng
- Beijing Institute of Brain Disorders, Laboratory of Brain Disorders, Ministry of Science and Technology, Collaborative Innovation Center for Brain Disorders, Beijing Advanced Innovation Center for Big Data-based Precision Medicine, Capital Medical University, Beijing, 100069, China
| | - Senbiao Fang
- School of Computer Science and Engineering, Central South University, Changsha, 410012, China
| | - Yuli Sun
- Beijing Institute of Brain Disorders, Laboratory of Brain Disorders, Ministry of Science and Technology, Collaborative Innovation Center for Brain Disorders, Beijing Advanced Innovation Center for Big Data-based Precision Medicine, Capital Medical University, Beijing, 100069, China
| | - Zequn Yang
- Beijing Institute of Brain Disorders, Laboratory of Brain Disorders, Ministry of Science and Technology, Collaborative Innovation Center for Brain Disorders, Beijing Advanced Innovation Center for Big Data-based Precision Medicine, Capital Medical University, Beijing, 100069, China
| | - Wei Zheng
- Beijing Institute of Brain Disorders, Laboratory of Brain Disorders, Ministry of Science and Technology, Collaborative Innovation Center for Brain Disorders, Beijing Advanced Innovation Center for Big Data-based Precision Medicine, Capital Medical University, Beijing, 100069, China
| | - Xunming Ji
- Beijing Institute of Brain Disorders, Laboratory of Brain Disorders, Ministry of Science and Technology, Collaborative Innovation Center for Brain Disorders, Beijing Advanced Innovation Center for Big Data-based Precision Medicine, Capital Medical University, Beijing, 100069, China.,Institute of Hypoxia Medicine, Xuanwu Hospital, Capital Medical University, Beijing, 100053, China
| | - Zehui Wu
- Beijing Institute of Brain Disorders, Laboratory of Brain Disorders, Ministry of Science and Technology, Collaborative Innovation Center for Brain Disorders, Beijing Advanced Innovation Center for Big Data-based Precision Medicine, Capital Medical University, Beijing, 100069, China
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Fortea E, Accardi A. A quantitative flux assay for the study of reconstituted Cl - channels and transporters. Methods Enzymol 2021; 652:243-272. [PMID: 34059284 DOI: 10.1016/bs.mie.2021.01.026] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
The recent deluge of high-resolution structural information on membrane proteins has not been accompanied by a comparable increase in our ability to functionally interrogate these proteins. Current functional assays often are not quantitative or are performed in conditions that significantly differ from those used in structural experiments, thus limiting the mechanistic correspondence between structural and functional experiments. A flux assay to determine quantitatively the functional properties of purified and reconstituted Cl- channels and transporters in membranes of defined lipid compositions is described. An ion-sensitive electrode is used to measure the rate of Cl- efflux from proteoliposomes reconstituted with the desired protein and the fraction of vesicles containing at least one active protein. These measurements enable the quantitative determination of key molecular parameters such as the unitary transport rate, the fraction of proteins that are active, and the molecular mass of the transport protein complex. The approach is illustrated using CLC-ec1, a CLC-type H+/Cl- exchanger as an example. The assay enables the quantitative study of a wide range of Cl- transporting molecules and proteins whose activity is modulated by ligands, voltage, and membrane composition as well as the investigation of the effects of compounds that directly inhibit or activate the reconstituted transport systems. The present assay is readily adapted to the study of transport systems with diverse substrate specificities and molecular characteristics, and the necessary modifications needed are discussed.
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Affiliation(s)
- Eva Fortea
- Department of Physiology and Biophysics, Weill Cornell Medical College, New York, NY, United States
| | - Alessio Accardi
- Department of Physiology and Biophysics, Weill Cornell Medical College, New York, NY, United States; Department of Anesthesiology, Weill Cornell Medical College, New York, NY, United States; Department of Biochemistry, Weill Cornell Medical College, New York, NY, United States.
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21
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Mitsuda M, Shiozaki A, Kudou M, Shimizu H, Arita T, Kosuga T, Konishi H, Komatsu S, Kubota T, Fujiwara H, Okamoto K, Kishimoto M, Konishi E, Otsuji E. Functional Analysis and Clinical Significance of Chloride Channel 2 Expression in Esophageal Squamous Cell Carcinoma. Ann Surg Oncol 2021; 28:5384-5397. [PMID: 33565032 DOI: 10.1245/s10434-021-09659-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Accepted: 01/13/2021] [Indexed: 12/17/2022]
Abstract
BACKGROUND Chloride channel 2 (CLCN2) was recently shown to affect tumor behavior. The present study examined the functions of CLCN2 in the regulation of genes that play a role in tumor progression, as well as its clinicopathological significance in esophageal squamous cell carcinoma (ESCC). METHODS Knockdown experiments were conducted using CLCN2-small-interfering RNA, and changes in proliferation, survival, and cellular movement in human ESCC cell lines were investigated. A microarray analysis of gene expression profiles in CLCN2-depleted ESCC cells was conducted. Fifty-four primary ESCC samples were examined by immunohistochemistry (IHC). RESULTS The strong expression of CLCN2 was detected in TE5 and KYSE70 cells. Downregulated expression of CLCN2 enhanced proliferation and decreased apoptosis, whereas its upregulation inhibited proliferation and increased apoptosis. The effects of lubiprostone, a CLCN2 activator, were also investigated. In lubiprostone-treated cells, proliferation was inhibited and apoptosis was increased. The microarray analysis demonstrated that interferon (IFN) signaling-related genes were downregulated in CLCN2-depleted cells. IHC showed the presence of CLCN2 in the cytoplasm and cell membranes of ESCC cells. The prognostic analysis revealed a relationship between weak CLCN2 expression and shorter overall survival. CONCLUSIONS The present results indicate that tumor progression is regulated by CLCN2 through its effects on IFN signaling. Furthermore, weak CLCN2 expression was associated with poorer outcomes in ESCC patients. The present study will contribute to a clearer understanding of the role of CLCN2 as a mediator of ESCC, as well as its use as a biomarker for this cancer.
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Affiliation(s)
- Masato Mitsuda
- Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Atsushi Shiozaki
- Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan.
| | - Michihiro Kudou
- Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Hiroki Shimizu
- Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Tomohiro Arita
- Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Toshiyuki Kosuga
- Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Hirotaka Konishi
- Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Shuhei Komatsu
- Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Takeshi Kubota
- Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Hitoshi Fujiwara
- Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Kazuma Okamoto
- Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Mitsuo Kishimoto
- Department of Pathology, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Eiichi Konishi
- Department of Pathology, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Eigo Otsuji
- Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan
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22
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Park C, Sakurai Y, Sato H, Kanda S, Iino Y, Kunitomo H. Roles of the ClC chloride channel CLH-1 in food-associated salt chemotaxis behavior of C. elegans. eLife 2021; 10:e55701. [PMID: 33492228 PMCID: PMC7834019 DOI: 10.7554/elife.55701] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Accepted: 01/04/2021] [Indexed: 01/19/2023] Open
Abstract
The ability of animals to process dynamic sensory information facilitates foraging in an ever-changing environment. However, molecular and neural mechanisms underlying such ability remain elusive. The ClC anion channels/transporters play a pivotal role in cellular ion homeostasis across all phyla. Here, we find a ClC chloride channel is involved in salt concentration chemotaxis of Caenorhabditis elegans. Genetic screening identified two altered-function mutations of clh-1 that disrupt experience-dependent salt chemotaxis. Using genetically encoded fluorescent sensors, we demonstrate that CLH-1 contributes to regulation of intracellular anion and calcium dynamics of salt-sensing neuron, ASER. The mutant CLH-1 reduced responsiveness of ASER to salt stimuli in terms of both temporal resolution and intensity, which disrupted navigation strategies for approaching preferred salt concentrations. Furthermore, other ClC genes appeared to act redundantly in salt chemotaxis. These findings provide insights into the regulatory mechanism of neuronal responsivity by ClCs that contribute to modulation of navigation behavior.
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Affiliation(s)
- Chanhyun Park
- Department of Biological Sciences, School of Science, The University of TokyoTokyoJapan
| | - Yuki Sakurai
- Department of Biological Sciences, School of Science, The University of TokyoTokyoJapan
| | - Hirofumi Sato
- Department of Biological Sciences, School of Science, The University of TokyoTokyoJapan
| | - Shinji Kanda
- Department of Biological Sciences, School of Science, The University of TokyoTokyoJapan
- Laboratory of Physiology, Atmosphere and Ocean Research Institute, The University of TokyoChibaJapan
| | - Yuichi Iino
- Department of Biological Sciences, School of Science, The University of TokyoTokyoJapan
| | - Hirofumi Kunitomo
- Department of Biological Sciences, School of Science, The University of TokyoTokyoJapan
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23
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Göppner C, Soria AH, Hoegg-Beiler MB, Jentsch TJ. Cellular basis of ClC-2 Cl - channel-related brain and testis pathologies. J Biol Chem 2021; 296:100074. [PMID: 33187987 PMCID: PMC7949093 DOI: 10.1074/jbc.ra120.016031] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2020] [Revised: 11/11/2020] [Accepted: 11/13/2020] [Indexed: 12/11/2022] Open
Abstract
The ClC-2 chloride channel is expressed in the plasma membrane of almost all mammalian cells. Mutations that cause the loss of ClC-2 function lead to retinal and testicular degeneration and leukodystrophy, whereas gain-of-function mutations cause hyperaldosteronism. Leukodystrophy is also observed with a loss of GlialCAM, a cell adhesion molecule that binds to ClC-2 in glia. GlialCAM changes the localization of ClC-2 and opens the channel by altering its gating. We now used cell type-specific deletion of ClC-2 in mice to show that retinal and testicular degeneration depend on a loss of ClC-2 in retinal pigment epithelial cells and Sertoli cells, respectively, whereas leukodystrophy was fully developed only when ClC-2 was disrupted in both astrocytes and oligodendrocytes. The leukodystrophy of Glialcam-/- mice could not be rescued by crosses with Clcn2op/op mice in which a mutation mimics the "opening" of ClC-2 by GlialCAM. These data indicate that GlialCAM-induced changes in biophysical properties of ClC-2 are irrelevant for GLIALCAM-related leukodystrophy. Taken together, our findings suggest that the pathology caused by Clcn2 disruption results from disturbed extracellular ion homeostasis and identifies the cells involved in this process.
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Affiliation(s)
- Corinna Göppner
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany; Max-Delbrück-Centrum für Molekulare Medizin (MDC), Berlin, Germany
| | - Audrey H Soria
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany; Max-Delbrück-Centrum für Molekulare Medizin (MDC), Berlin, Germany
| | - Maja B Hoegg-Beiler
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany; Max-Delbrück-Centrum für Molekulare Medizin (MDC), Berlin, Germany
| | - Thomas J Jentsch
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany; Max-Delbrück-Centrum für Molekulare Medizin (MDC), Berlin, Germany; NeuroCure Cluster of Excellence, Charité Universitätsmedizin, Berlin, Germany.
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24
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Fernandez-Abascal J, Graziano B, Encalada N, Bianchi L. Glial Chloride Channels in the Function of the Nervous System Across Species. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1349:195-223. [PMID: 35138616 DOI: 10.1007/978-981-16-4254-8_10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
In the nervous system, the concentration of Cl- in neurons that express GABA receptors plays a key role in establishing whether these neurons are excitatory, mostly during early development, or inhibitory. Thus, much attention has been dedicated to understanding how neurons regulate their intracellular Cl- concentration. However, regulation of the extracellular Cl- concentration by other cells of the nervous system, including glia and microglia, is as important because it ultimately affects the Cl- equilibrium potential across the neuronal plasma membrane. Moreover, Cl- ions are transported in and out of the cell, via either passive or active transporter systems, as counter ions for K+ whose concentration in the extracellular environment of the nervous system is tightly regulated because it directly affects neuronal excitability. In this book chapter, we report on the Cl- channel types expressed in the various types of glial cells focusing on the role they play in the function of the nervous system in health and disease. Furthermore, we describe the types of stimuli that these channels are activated by, the other solutes that they may transport, and the involvement of these channels in processes such as pH regulation and Regulatory Volume Decrease (RVD). The picture that emerges is one of the glial cells expressing a variety of Cl- channels, encoded by members of different gene families, involved both in short- and long-term regulation of the nervous system function. Finally, we report data on invertebrate model organisms, such as C. elegans and Drosophila, that are revealing important and previously unsuspected functions of some of these channels in the context of living and behaving animals.
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Affiliation(s)
- Jesus Fernandez-Abascal
- Department Physiology and Biophysics, University of Miami, Miller School of Medicine, Miami, FL, USA
| | - Bianca Graziano
- Department Physiology and Biophysics, University of Miami, Miller School of Medicine, Miami, FL, USA
| | - Nicole Encalada
- Department Physiology and Biophysics, University of Miami, Miller School of Medicine, Miami, FL, USA
| | - Laura Bianchi
- Department Physiology and Biophysics, University of Miami, Miller School of Medicine, Miami, FL, USA.
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25
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Kwon HC, Yu Y, Fairclough RH, Chen TY. Proton-dependent inhibition, inverted voltage activation, and slow gating of CLC-0 Chloride Channel. PLoS One 2020; 15:e0240704. [PMID: 33362212 PMCID: PMC7757909 DOI: 10.1371/journal.pone.0240704] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2020] [Accepted: 12/03/2020] [Indexed: 11/21/2022] Open
Abstract
CLC-0, a prototype Cl- channel in the CLC family, employs two gating mechanisms that control its ion-permeation pore: fast gating and slow gating. The negatively-charged sidechain of a pore glutamate residue, E166, is known to be the fast gate, and the swinging of this sidechain opens or closes the pore of CLC-0 on the millisecond time scale. The other gating mechanism, slow gating, operates with much slower kinetics in the range of seconds to tens or even hundreds of seconds, and it is thought to involve still-unknown conformational rearrangements. Here, we find that low intracellular pH (pHi) facilitates the closure of the CLC-0’s slow gate, thus generating current inhibition. The rate of low pHi-induced current inhibition increases with intracellular H+ concentration ([H+]i)—the time constants of current inhibition by low pHi = 4.5, 5.5 and 6 are roughly 0.1, 1 and 10 sec, respectively, at room temperature. In comparison, the time constant of the slow gate closure at pHi = 7.4 at room temperature is hundreds of seconds. The inhibition by low pHi is significantly less prominent in mutants favoring the slow-gate open state (such as C212S and Y512A), further supporting the fact that intracellular H+ enhances the slow-gate closure in CLC-0. A fast inhibition by low pHi causes an apparent inverted voltage-dependent activation in the wild-type CLC-0, a behavior similar to those in some channel mutants such as V490W in which only membrane hyperpolarization can open the channel. Interestingly, when V490W mutation is constructed in the background of C212S or Y512A mutation, the inverted voltage-dependent activation disappears. We propose that the slow kinetics of CLC-0’s slow-gate closure may be due to low [H+]i rather than due to the proposed large conformational change of the channel protein. Our results also suggest that the inverted voltage-dependent opening observed in some mutant channels may result from fast closure of the slow gate by the mutations.
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Affiliation(s)
- Hwoi Chan Kwon
- Biophysics Graduate Program, University of California, Davis, California, United States of America
| | - Yawei Yu
- BMCDB Graduate Program, University of California, Davis, California, United States of America
| | - Robert H. Fairclough
- Biophysics Graduate Program, University of California, Davis, California, United States of America
- BMCDB Graduate Program, University of California, Davis, California, United States of America
- Center for Neuroscience, University of California, Davis, California, United States of America
| | - Tsung-Yu Chen
- Biophysics Graduate Program, University of California, Davis, California, United States of America
- BMCDB Graduate Program, University of California, Davis, California, United States of America
- Department of Neurology, University of California, Davis, California, United States of America
- Center for Neuroscience, University of California, Davis, California, United States of America
- * E-mail:
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26
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Koster AK, Reese AL, Kuryshev Y, Wen X, McKiernan KA, Gray EE, Wu C, Huguenard JR, Maduke M, Du Bois J. Development and validation of a potent and specific inhibitor for the CLC-2 chloride channel. Proc Natl Acad Sci U S A 2020; 117:32711-32721. [PMID: 33277431 PMCID: PMC7768775 DOI: 10.1073/pnas.2009977117] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
CLC-2 is a voltage-gated chloride channel that is widely expressed in mammalian tissues. In the central nervous system, CLC-2 appears in neurons and glia. Studies to define how this channel contributes to normal and pathophysiological function in the central nervous system raise questions that remain unresolved, in part due to the absence of precise pharmacological tools for modulating CLC-2 activity. Herein, we describe the development and optimization of AK-42, a specific small-molecule inhibitor of CLC-2 with nanomolar potency (IC50 = 17 ± 1 nM). AK-42 displays unprecedented selectivity (>1,000-fold) over CLC-1, the closest CLC-2 homolog, and exhibits no off-target engagement against a panel of 61 common channels, receptors, and transporters expressed in brain tissue. Computational docking, validated by mutagenesis and kinetic studies, indicates that AK-42 binds to an extracellular vestibule above the channel pore. In electrophysiological recordings of mouse CA1 hippocampal pyramidal neurons, AK-42 acutely and reversibly inhibits CLC-2 currents; no effect on current is observed on brain slices taken from CLC-2 knockout mice. These results establish AK-42 as a powerful tool for investigating CLC-2 neurophysiology.
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Affiliation(s)
- Anna K Koster
- Department of Chemistry, Stanford University, Stanford, CA 94305
- Department of Molecular & Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305
| | - Austin L Reese
- Department of Neurology & Neurological Sciences, Stanford University School of Medicine, Stanford, CA 94305
| | - Yuri Kuryshev
- Charles River Laboratories Cleveland, Inc., Cleveland, OH 44128
| | - Xianlan Wen
- Department of Molecular & Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305
| | - Keri A McKiernan
- Department of Chemistry, Stanford University, Stanford, CA 94305
| | - Erin E Gray
- Department of Chemistry, Stanford University, Stanford, CA 94305
| | - Caiyun Wu
- Charles River Laboratories Cleveland, Inc., Cleveland, OH 44128
| | - John R Huguenard
- Department of Neurology & Neurological Sciences, Stanford University School of Medicine, Stanford, CA 94305;
| | - Merritt Maduke
- Department of Molecular & Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305;
| | - J Du Bois
- Department of Chemistry, Stanford University, Stanford, CA 94305;
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27
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Martínez-Rojas VA, Jiménez-Garduño AM, Michelatti D, Tosatto L, Marchioretto M, Arosio D, Basso M, Pennuto M, Musio C. ClC-2-like Chloride Current Alterations in a Cell Model of Spinal and Bulbar Muscular Atrophy, a Polyglutamine Disease. J Mol Neurosci 2020; 71:662-674. [PMID: 32856205 DOI: 10.1007/s12031-020-01687-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Accepted: 08/14/2020] [Indexed: 12/21/2022]
Abstract
Spinal and bulbar muscular atrophy (SBMA) is a neuromuscular disease caused by expansions of a polyglutamine (polyQ) tract in the androgen receptor (AR) gene. SBMA is associated with the progressive loss of lower motor neurons, together with muscle weakness and atrophy. PolyQ-AR is converted to a toxic species upon binding to its natural ligands, testosterone, and dihydrotestosterone (DHT). Our previous patch-clamp studies on a motor neuron-derived cell model of SBMA showed alterations in voltage-gated ion currents. Here, we identified and characterized chloride currents most likely belonging to the chloride channel-2 (ClC-2) subfamily, which showed significantly increased amplitudes in the SBMA cells. The treatment with the pituitary adenylyl cyclase-activating polypeptide (PACAP), a neuropeptide with a proven protective effect in a mouse model of SBMA, recovered chloride channel current alterations in SBMA cells. These observations suggest that the CIC-2 currents are affected in SBMA, an alteration that may contribute and potentially determine the pathophysiology of the disease.
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Affiliation(s)
- Vladimir A Martínez-Rojas
- Institute of Biophysics (IBF), Trento Unit, National Research Council (CNR) & LabSSAH, Bruno Kessler Foundation (FBK), Trento, Italy
| | - Aura M Jiménez-Garduño
- Institute of Biophysics (IBF), Trento Unit, National Research Council (CNR) & LabSSAH, Bruno Kessler Foundation (FBK), Trento, Italy.,Departamento de Ciencias de la Salud, Escuela de Ciencias, Universidad de las Américas Puebla (UDLAP), San Andrés Cholula, Puebla, Mexico
| | - Daniela Michelatti
- Institute of Biophysics (IBF), Trento Unit, National Research Council (CNR) & LabSSAH, Bruno Kessler Foundation (FBK), Trento, Italy.,CIBIO Department, Laboratory of Chromatin Biology and Epigenetics, University of Trento, Trento, Italy
| | - Laura Tosatto
- Institute of Biophysics (IBF), Trento Unit, National Research Council (CNR) & LabSSAH, Bruno Kessler Foundation (FBK), Trento, Italy
| | - Marta Marchioretto
- Institute of Biophysics (IBF), Trento Unit, National Research Council (CNR) & LabSSAH, Bruno Kessler Foundation (FBK), Trento, Italy
| | - Daniele Arosio
- Institute of Biophysics (IBF), Trento Unit, National Research Council (CNR) & LabSSAH, Bruno Kessler Foundation (FBK), Trento, Italy
| | - Manuela Basso
- CIBIO Department, Laboratory of Transcriptional Neurobiology, University of Trento, Trento, Italy
| | - Maria Pennuto
- Department of Biomedical Sciences, University of Padova, Padova, Italy.,Padova Neuroscience Center (PNC), University of Padova, Padova, Italy.,Veneto Institute of Molecular Medicine, Padova, Italy
| | - Carlo Musio
- Institute of Biophysics (IBF), Trento Unit, National Research Council (CNR) & LabSSAH, Bruno Kessler Foundation (FBK), Trento, Italy.
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28
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Zhang Y, Wu Q, Fang S, Li S, Zheng H, Zhang Y, Ikhwanuddin M, Ma H. mRNA profile provides novel insights into stress adaptation in mud crab megalopa, Scylla paramamosain after salinity stress. BMC Genomics 2020; 21:559. [PMID: 32795331 PMCID: PMC7430823 DOI: 10.1186/s12864-020-06965-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Accepted: 07/30/2020] [Indexed: 02/06/2023] Open
Abstract
Background Mud crab, Scylla paramamosain, a euryhaline crustacean species, mainly inhabits the Indo-Western Pacific region. Wild mud crab spawn in high-salt condition and the salinity reduced with the growth of the hatching larvae. When the larvae grow up to megalopa, they migrate back to estuaries and coasts in virtue of the flood tide, settle and recruit adult habitats and metamorphose into the crablet stage. Adult crab can even survive in a wide salinity of 0–35 ppt. To investigate the mRNA profile after salinity stress, S. paramamosain megalopa were exposed to different salinity seawater (low, 14 ppt; control, 25 ppt; high, 39 ppt). Results Firstly, from the expression profiles of Na+/K+/2Cl- cotransporter, chloride channel protein 2, and ABC transporter, it turned out that the 24 h might be the most influenced duration in the short-term stress. We collected megalopa under different salinity for 24 h and then submitted to mRNA profiling. Totally, 57.87 Gb Clean Data were obtained. The comparative genomic analysis detected 342 differentially expressed genes (DEGs). The most significantly DEGs include gamma-butyrobetaine dioxygenase-like, facilitated trehalose transporter Tret1, sodium/potassium-transporting ATPase subunit alpha, rhodanese 1-like protein, etc. And the significantly enriched pathways were lysine degradation, choline metabolism in cancer, phospholipase D signaling pathway, Fc gamma R-mediated phagocytosis, and sphingolipid signaling pathway. The results indicate that in the short-term salinity stress, the megalopa might regulate some mechanism such as metabolism, immunity responses, osmoregulation to adapt to the alteration of the environment. Conclusions This study represents the first genome-wide transcriptome analysis of S. paramamosain megalopa for studying its stress adaption mechanisms under different salinity. The results reveal numbers of genes modified by salinity stress and some important pathways, which will provide valuable resources for discovering the molecular basis of salinity stress adaptation of S. paramamosain larvae and further boost the understanding of the potential molecular mechanisms of salinity stress adaptation for crustacean species.
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Affiliation(s)
- Yin Zhang
- Guangdong Provincial Key Laboratory of Marine Biotechnology, Institute of Marine Sciences, Shantou University, 243 Daxue Road, Shantou, 515063, China.,STU-UMT Joint Shellfish Research Laboratory, Shantou University, Shantou, 515063, China
| | - Qingyang Wu
- Guangdong Provincial Key Laboratory of Marine Biotechnology, Institute of Marine Sciences, Shantou University, 243 Daxue Road, Shantou, 515063, China. .,STU-UMT Joint Shellfish Research Laboratory, Shantou University, Shantou, 515063, China.
| | - Shaobin Fang
- Guangdong Provincial Key Laboratory of Marine Biotechnology, Institute of Marine Sciences, Shantou University, 243 Daxue Road, Shantou, 515063, China.,STU-UMT Joint Shellfish Research Laboratory, Shantou University, Shantou, 515063, China
| | - Shengkang Li
- Guangdong Provincial Key Laboratory of Marine Biotechnology, Institute of Marine Sciences, Shantou University, 243 Daxue Road, Shantou, 515063, China.,STU-UMT Joint Shellfish Research Laboratory, Shantou University, Shantou, 515063, China
| | - Huaiping Zheng
- Guangdong Provincial Key Laboratory of Marine Biotechnology, Institute of Marine Sciences, Shantou University, 243 Daxue Road, Shantou, 515063, China.,STU-UMT Joint Shellfish Research Laboratory, Shantou University, Shantou, 515063, China
| | - Yueling Zhang
- Guangdong Provincial Key Laboratory of Marine Biotechnology, Institute of Marine Sciences, Shantou University, 243 Daxue Road, Shantou, 515063, China.,STU-UMT Joint Shellfish Research Laboratory, Shantou University, Shantou, 515063, China
| | - Mhd Ikhwanuddin
- STU-UMT Joint Shellfish Research Laboratory, Shantou University, Shantou, 515063, China.,Institute of Tropical Aquaculture, Universiti Malaysia Terengganu, 21030, Kuala Terengganu, Malaysia
| | - Hongyu Ma
- Guangdong Provincial Key Laboratory of Marine Biotechnology, Institute of Marine Sciences, Shantou University, 243 Daxue Road, Shantou, 515063, China. .,STU-UMT Joint Shellfish Research Laboratory, Shantou University, Shantou, 515063, China. .,Institute of Tropical Aquaculture, Universiti Malaysia Terengganu, 21030, Kuala Terengganu, Malaysia.
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29
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Catalán MA, Julio-Kalajzić F, Niemeyer MI, Cid LP, Sepúlveda FV. Short Chain Fatty Acids Effect on Chloride Channel ClC-2 as a Possible Mechanism for Lubiprostone Intestinal Action. Cells 2020; 9:cells9081781. [PMID: 32722648 PMCID: PMC7464869 DOI: 10.3390/cells9081781] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 07/22/2020] [Accepted: 07/23/2020] [Indexed: 01/22/2023] Open
Abstract
Lubiprostone, a 20-carbon synthetic fatty acid used for the treatment of constipation, is thought to act through an action on Cl− channel ClC-2. Short chain fatty acids (SCFAs) are produced and absorbed in the distal intestine. We explore whether SCFAs affect ClC-2, re-examine a possible direct effect of lubiprostone on ClC-2, and use mice deficient in ClC-2 to stringently address the hypothesis that the epithelial effect of lubiprostone targets this anion channel. Patch-clamp whole cell recordings of ClC-2 expressed in mammalian cells are used to assay SCFA and lubiprostone effects. Using chamber measurements of ion current in mice deficient in ClC-2 or CFTR channels served to analyze the target of lubiprostone in the distal intestinal epithelium. Intracellular SCFAs had a dual action on ClC-2, partially inhibiting conduction but, importantly, facilitating the voltage activation of ClC-2. Intra- or extracellular lubiprostone had no effect on ClC-2 currents. Lubiprostone elicited a secretory current across colonic epithelia that was increased in mice deficient in ClC-2, consistent with the channel’s proposed proabsorptive function, but absent from those deficient in CFTR. Whilst SCFAs might exert a physiological effect on ClC-2 as part of their known proabsorptive effect, ClC-2 plays no part in the lubiprostone intestinal effect that appears mediated by CFTR activation.
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Affiliation(s)
- Marcelo A. Catalán
- Centro de Estudios Científicos (CECs), Avenida Arturo Prat 514, Valdivia 5110466, Chile; (F.J.-K.); (M.I.N.); (L.P.C.)
- Instituto de Fisiología, Facultad de Medicina, Universidad Austral de Chile, Valdivia 5090000, Chile
- Correspondence: (M.A.C.); (F.V.S.); Tel.: +56-63-2221686 (M.A.C.)
| | - Francisca Julio-Kalajzić
- Centro de Estudios Científicos (CECs), Avenida Arturo Prat 514, Valdivia 5110466, Chile; (F.J.-K.); (M.I.N.); (L.P.C.)
| | - María Isabel Niemeyer
- Centro de Estudios Científicos (CECs), Avenida Arturo Prat 514, Valdivia 5110466, Chile; (F.J.-K.); (M.I.N.); (L.P.C.)
| | - Luis Pablo Cid
- Centro de Estudios Científicos (CECs), Avenida Arturo Prat 514, Valdivia 5110466, Chile; (F.J.-K.); (M.I.N.); (L.P.C.)
| | - Francisco V. Sepúlveda
- Centro de Estudios Científicos (CECs), Avenida Arturo Prat 514, Valdivia 5110466, Chile; (F.J.-K.); (M.I.N.); (L.P.C.)
- Correspondence: (M.A.C.); (F.V.S.); Tel.: +56-63-2221686 (M.A.C.)
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30
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Fu SJ, Hu MC, Peng YJ, Fang HY, Hsiao CT, Chen TY, Jeng CJ, Tang CY. CUL4-DDB1-CRBN E3 Ubiquitin Ligase Regulates Proteostasis of ClC-2 Chloride Channels: Implication for Aldosteronism and Leukodystrophy. Cells 2020; 9:cells9061332. [PMID: 32466489 PMCID: PMC7348978 DOI: 10.3390/cells9061332] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2020] [Revised: 05/20/2020] [Accepted: 05/25/2020] [Indexed: 12/27/2022] Open
Abstract
Voltage-gated ClC-2 channels are essential for chloride homeostasis. Complete knockout of mouse ClC-2 leads to testicular degeneration and neuronal myelin vacuolation. Gain-of-function and loss-of-function mutations in the ClC-2-encoding human CLCN2 gene are linked to the genetic diseases aldosteronism and leukodystrophy, respectively. The protein homeostasis (proteostasis) mechanism of ClC-2 is currently unclear. Here, we aimed to identify the molecular mechanism of endoplasmic reticulum-associated degradation of ClC-2, and to explore the pathophysiological significance of disease-associated anomalous ClC-2 proteostasis. In both heterologous expression system and native neuronal and testicular cells, ClC-2 is subject to significant regulation by cullin-RING E3 ligase-mediated polyubiquitination and proteasomal degradation. The cullin 4 (CUL4)-damage-specific DNA binding protein 1 (DDB1)-cereblon (CRBN) E3 ubiquitin ligase co-exists in the same complex with and promotes the degradation of ClC-2 channels. The CRBN-targeting immunomodulatory drug lenalidomide and the cullin E3 ligase inhibitor MLN4924 promotes and attenuates, respectively, proteasomal degradation of ClC-2. Analyses of disease-related ClC-2 mutants reveal that aldosteronism and leukodystrophy are associated with opposite alterations in ClC-2 proteostasis. Modifying CUL4 E3 ligase activity with lenalidomide and MLN4924 ameliorates disease-associated ClC-2 proteostasis abnormality. Our results highlight the significant role and therapeutic potential of CUL4 E3 ubiquitin ligase in regulating ClC-2 proteostasis.
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Affiliation(s)
- Ssu-Ju Fu
- Department of Physiology, College of Medicine, National Taiwan University, Taipei 10051, Taiwan; (S.-J.F.); (M.-C.H.); (Y.-J.P.); (H.-Y.F.); (C.-T.H.)
| | - Meng-Chun Hu
- Department of Physiology, College of Medicine, National Taiwan University, Taipei 10051, Taiwan; (S.-J.F.); (M.-C.H.); (Y.-J.P.); (H.-Y.F.); (C.-T.H.)
| | - Yi-Jheng Peng
- Department of Physiology, College of Medicine, National Taiwan University, Taipei 10051, Taiwan; (S.-J.F.); (M.-C.H.); (Y.-J.P.); (H.-Y.F.); (C.-T.H.)
| | - Hsin-Yu Fang
- Department of Physiology, College of Medicine, National Taiwan University, Taipei 10051, Taiwan; (S.-J.F.); (M.-C.H.); (Y.-J.P.); (H.-Y.F.); (C.-T.H.)
| | - Cheng-Tsung Hsiao
- Department of Physiology, College of Medicine, National Taiwan University, Taipei 10051, Taiwan; (S.-J.F.); (M.-C.H.); (Y.-J.P.); (H.-Y.F.); (C.-T.H.)
- Department of Neurology, Taipei Veterans General Hospital, Taipei 12217, Taiwan
| | - Tsung-Yu Chen
- Center for Neuroscience and Department of Neurology, University of California, Davis, CA 95616, USA;
| | - Chung-Jiuan Jeng
- Institute of Anatomy and Cell Biology, School of Medicine, National Yang-Ming University, Taipei 12212, Taiwan
- Brain Research Center, National Yang-Ming University, Taipei 12212, Taiwan
- Correspondence: (C.-J.J.); (C.-Y.T.)
| | - Chih-Yung Tang
- Department of Physiology, College of Medicine, National Taiwan University, Taipei 10051, Taiwan; (S.-J.F.); (M.-C.H.); (Y.-J.P.); (H.-Y.F.); (C.-T.H.)
- Graduate Institute of Brain and Mind Sciences, College of Medicine, National Taiwan University, Taipei 10051, Taiwan
- Correspondence: (C.-J.J.); (C.-Y.T.)
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31
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Johnson CK, Fernandez-Abascal J, Wang Y, Wang L, Bianchi L. The Na +-K +-ATPase is needed in glia of touch receptors for responses to touch in C. elegans. J Neurophysiol 2020; 123:2064-2074. [PMID: 32292107 DOI: 10.1152/jn.00636.2019] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Four of the five types of mammalian mechanosensors are composed of nerve endings and accessory cells. In Caenorhabditis elegans we showed that glia support the function of nose touch neurons via the activity of glial Na+ and K+ channels. We show here that a third regulator of Na+ and K+, the Na+-K+-ATPase, is needed in glia of nose touch neurons for touch. Importantly, we show that two Na+-K+-ATPase genes are needed for the function rather than structural integrity and that their ion transport activity is crucial for touch. Finally, when glial Na+-K+-ATPase genes are knocked out, touch can be restored by activation of a third Na+-K+-ATPase. Taken together, these data show the requirement in glia of touch neurons of the function of the Na+-K+-ATPase. These data underscore the importance of the homeostasis of Na+ and K+, most likely in the space surrounding touch neurons, in touch sensation, a function that might be conserved across species.NEW & NOTEWORTHY Increasing evidence supports that accessory cells in mechanosensors regulate neuronal output; however, the glial molecular mechanisms that control this regulation are not fully understood. We show here in Caenorhabditis elegans that specific glial Na+-K+-ATPase genes are needed for nose touch-avoidance behavior. Our data support the requirement of these Na+-K+-ATPases for homeostasis of Na+ and K+ in nose touch receptors. Our data add to our understanding of glial regulation of mechanosensors.
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Affiliation(s)
- Christina K Johnson
- Department Physiology and Biophysics, University of Miami Miller School of Medicine, Miami, Florida
| | - Jesus Fernandez-Abascal
- Department Physiology and Biophysics, University of Miami Miller School of Medicine, Miami, Florida
| | - Ying Wang
- Department Physiology and Biophysics, University of Miami Miller School of Medicine, Miami, Florida
| | - Lei Wang
- Department Physiology and Biophysics, University of Miami Miller School of Medicine, Miami, Florida
| | - Laura Bianchi
- Department Physiology and Biophysics, University of Miami Miller School of Medicine, Miami, Florida
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32
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McKiernan KA, Koster AK, Maduke M, Pande VS. Dynamical model of the CLC-2 ion channel reveals conformational changes associated with selectivity-filter gating. PLoS Comput Biol 2020; 16:e1007530. [PMID: 32226009 PMCID: PMC7145265 DOI: 10.1371/journal.pcbi.1007530] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Revised: 04/09/2020] [Accepted: 11/05/2019] [Indexed: 12/18/2022] Open
Abstract
This work reports a dynamical Markov state model of CLC-2 "fast" (pore) gating, based on 600 microseconds of molecular dynamics (MD) simulation. In the starting conformation of our CLC-2 model, both outer and inner channel gates are closed. The first conformational change in our dataset involves rotation of the inner-gate backbone along residues S168-G169-I170. This change is strikingly similar to that observed in the cryo-EM structure of the bovine CLC-K channel, though the volume of the intracellular (inner) region of the ion conduction pathway is further expanded in our model. From this state (inner gate open and outer gate closed), two additional states are observed, each involving a unique rotameric flip of the outer-gate residue GLUex. Both additional states involve conformational changes that orient GLUex away from the extracellular (outer) region of the ion conduction pathway. In the first additional state, the rotameric flip of GLUex results in an open, or near-open, channel pore. The equilibrium population of this state is low (∼1%), consistent with the low open probability of CLC-2 observed experimentally in the absence of a membrane potential stimulus (0 mV). In the second additional state, GLUex rotates to occlude the channel pore. This state, which has a low equilibrium population (∼1%), is only accessible when GLUex is protonated. Together, these pathways model the opening of both an inner and outer gate within the CLC-2 selectivity filter, as a function of GLUex protonation. Collectively, our findings are consistent with published experimental analyses of CLC-2 gating and provide a high-resolution structural model to guide future investigations.
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Affiliation(s)
- Keri A. McKiernan
- Department of Chemistry, Stanford University, Stanford, California, United States of America
| | - Anna K. Koster
- Department of Chemistry, Stanford University, Stanford, California, United States of America
- Department of Molecular & Cellular Physiology, Stanford University, Stanford, California, United States of America
| | - Merritt Maduke
- Department of Molecular & Cellular Physiology, Stanford University, Stanford, California, United States of America
| | - Vijay S. Pande
- Department of Bioengineering, Stanford University, Stanford, California, United States of America
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33
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Abstract
Primary aldosteronism (PA) is the most common form of secondary hypertension affecting 5%-10% of patients with arterial hypertension. In PA, high blood pressure is associated with high aldosterone and low renin levels, and often hypokalemia. In a majority of cases, autonomous aldosterone production by the adrenal gland is caused by an aldosterone producing adenoma (APA) or bilateral adrenal hyperplasia (BAH). During the last ten years, a better knowledge of the pathophysiology of PA came from the discovery of somatic and germline mutations in different genes in both sporadic and familial forms of the disease. Those genes code for ion channels and pumps, as well as proteins involved in adrenal cortex development and function. Targeted next generation sequencing following immunohistochemistry guided detection of aldosterone synthase expression allows detection of somatic mutations in up to 90% of APA, while whole exome sequencing has discovered the genetic causes of four different familial forms of PA. The identification, in BAH, of somatic mutations in aldosterone producing cell clusters open new perspectives in our understanding of the bilateral form of the disease and the development of new therapeutic approaches.
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Affiliation(s)
| | | | - Maria-Christina Zennaro
- Université de Paris, PARCC, INSERM, Paris, France; Assistance Publique-Hôpitaux de Paris, Hôpital Européen Georges Pompidou, Service de Génétique, Paris, France
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34
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Physiological Significance of Ion Transporters and Channels in the Stomach and Pathophysiological Relevance in Gastric Cancer. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2020; 2020:2869138. [PMID: 32104192 PMCID: PMC7040404 DOI: 10.1155/2020/2869138] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Revised: 12/17/2019] [Accepted: 01/08/2020] [Indexed: 12/26/2022]
Abstract
Gastric cancer (GC) is a highly invasive and fatal malignant disease that accounts for 5.7% of new global cancer cases and is the third leading cause of cancer-related death. Acid/base homeostasis is critical for organisms because protein and enzyme function, cellular structure, and plasma membrane permeability change with pH. Various ion transporters are expressed in normal gastric mucosal epithelial cells and regulate gastric acid secretion, ion transport, and fluid absorption, thereby stabilizing the differentiation and homeostasis of gastric mucosal epithelial cells. Ion transporter dysfunction results in disordered ion transport, mucosa barrier dysfunction, and acid/base disturbances, causing gastric acid-related diseases such as chronic atrophic gastritis (CAG) and GC. This review summarizes the physiological functions of multiple ion transporters and channels in the stomach, including Cl− channels, Cl−/HCO3− exchangers, sodium/hydrogen exchangers (NHEs), and potassium (K+) channels, and their pathophysiological relevance in GC.
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35
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Hansen TH, Yan Y, Ahlberg G, Vad OB, Refsgaard L, Dos Santos JL, Mutsaers N, Svendsen JH, Olesen MS, Bentzen BH, Schmitt N. A Novel Loss-of-Function Variant in the Chloride Ion Channel Gene Clcn2 Associates with Atrial Fibrillation. Sci Rep 2020; 10:1453. [PMID: 31996765 PMCID: PMC6989500 DOI: 10.1038/s41598-020-58475-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Accepted: 01/15/2020] [Indexed: 11/09/2022] Open
Abstract
Atrial Fibrillation (AF) is the most common cardiac arrhythmia. Its pathogenesis is complex and poorly understood. Whole exome sequencing of Danish families with AF revealed a novel four nucleotide deletion c.1041_1044del in CLCN2 shared by affected individuals. We aimed to investigate the role of genetic variation of CLCN2 encoding the inwardly rectifying chloride channel ClC-2 as a risk factor for the development of familiar AF. The effect of the CLCN2 variant was evaluated by electrophysiological recordings on transiently transfected cells. We used quantitative PCR to assess CLCN2 mRNA expression levels in human atrial and ventricular tissue samples. The nucleotide deletion CLCN2 c.1041_1044del results in a frame-shift and premature stop codon. The truncated ClC-2 p.V347fs channel does not conduct current. Co-expression with wild-type ClC-2, imitating the heterozygote state of the patients, resulted in a 50% reduction in macroscopic current, suggesting an inability of truncated ClC-2 protein to form channel complexes with wild type channel subunits. Quantitative PCR experiments using human heart tissue from healthy donors demonstrated that CLCN2 is expressed across all four heart chambers. Our genetic and functional data points to a possible link between loss of ClC-2 function and an increased risk of developing AF.
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Affiliation(s)
- Thea Hyttel Hansen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,ALK-Abelló A/S, 2970, Hørsholm, Denmark
| | - Yannan Yan
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Gustav Ahlberg
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Laboratory for Molecular Cardiology, Department of Cardiology, The Heart Centre, Righospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - Oliver Bundgaard Vad
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Laboratory for Molecular Cardiology, Department of Cardiology, The Heart Centre, Righospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - Lena Refsgaard
- Laboratory for Molecular Cardiology, Department of Cardiology, The Heart Centre, Righospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - Joana Larupa Dos Santos
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Nancy Mutsaers
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Jesper Hastrup Svendsen
- Laboratory for Molecular Cardiology, Department of Cardiology, The Heart Centre, Righospitalet, Copenhagen University Hospital, Copenhagen, Denmark.,Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Morten Salling Olesen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Laboratory for Molecular Cardiology, Department of Cardiology, The Heart Centre, Righospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - Bo Hjorth Bentzen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Nicole Schmitt
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
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36
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Tevosian SG, Fox SC, Ghayee HK. Molecular Mechanisms of Primary Aldosteronism. Endocrinol Metab (Seoul) 2019; 34:355-366. [PMID: 31884735 PMCID: PMC6935778 DOI: 10.3803/enm.2019.34.4.355] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Revised: 12/02/2019] [Accepted: 12/09/2019] [Indexed: 01/11/2023] Open
Abstract
Primary aldosteronism (PA) results from excess production of mineralocorticoid hormone aldosterone by the adrenal cortex. It is normally caused either by unilateral aldosterone-producing adenoma (APA) or by bilateral aldosterone excess as a result of bilateral adrenal hyperplasia. PA is the most common cause of secondary hypertension and associated morbidity and mortality. While most cases of PA are sporadic, an important insight into this debilitating disease has been derived through investigating the familial forms of the disease that affect only a minor fraction of PA patients. The advent of gene expression profiling has shed light on the genes and intracellular signaling pathways that may play a role in the pathogenesis of these tumors. The genetic basis for several forms of familial PA has been uncovered in recent years although the list is likely to expand. Recently, the work from several laboratories provided evidence for the involvement of mammalian target of rapamycin pathway and inflammatory cytokines in APAs; however, their mechanism of action in tumor development and pathophysiology remains to be understood.
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Affiliation(s)
- Sergei G Tevosian
- Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL, USA
| | - Shawna C Fox
- Department of Pharmacotherapy and Translational Research, College of Pharmacy, University of Florida, Gainesville, FL, USA
| | - Hans K Ghayee
- Division of Endocrinology, Department of Medicine, Malcom Randall VA Medical Center, University of Florida, Gainesville, FL, USA.
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37
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Göppner C, Orozco IJ, Hoegg-Beiler MB, Soria AH, Hübner CA, Fernandes-Rosa FL, Boulkroun S, Zennaro MC, Jentsch TJ. Pathogenesis of hypertension in a mouse model for human CLCN2 related hyperaldosteronism. Nat Commun 2019; 10:4678. [PMID: 31615979 PMCID: PMC6794291 DOI: 10.1038/s41467-019-12113-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Accepted: 08/21/2019] [Indexed: 12/31/2022] Open
Abstract
Human primary aldosteronism (PA) can be caused by mutations in several ion channel genes but mouse models replicating this condition are lacking. We now show that almost all known PA-associated CLCN2 mutations markedly increase ClC-2 chloride currents and generate knock-in mice expressing a constitutively open ClC-2 Cl− channel as mouse model for PA. The Clcn2op allele strongly increases the chloride conductance of zona glomerulosa cells, provoking a strong depolarization and increasing cytoplasmic Ca2+ concentration. Clcn2op mice display typical features of human PA, including high serum aldosterone in the presence of low renin activity, marked hypertension and hypokalemia. These symptoms are more pronounced in homozygous Clcn2op/op than in heterozygous Clcn2+/op mice. This difference is attributed to the unexpected finding that only ~50 % of Clcn2+/op zona glomerulosa cells are depolarized. By reproducing essential features of human PA, Clcn2op mice are a valuable model to study the pathological mechanisms underlying this disease. Mutations in the chloride channel ClC-2 have been found in primary aldosteronism (PA). Here, Göppner et al. generate transgenic mice expressing a mutant form of ClC-2 that displays increased chloride currents like patient mutations, and find it recapitulates the key pathological features of PA.
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Affiliation(s)
- Corinna Göppner
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany.,Max-Delbrück-Centrum für Molekulare Medizin (MDC), Berlin, Germany
| | - Ian J Orozco
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany.,Max-Delbrück-Centrum für Molekulare Medizin (MDC), Berlin, Germany
| | - Maja B Hoegg-Beiler
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany.,Max-Delbrück-Centrum für Molekulare Medizin (MDC), Berlin, Germany
| | - Audrey H Soria
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany.,Max-Delbrück-Centrum für Molekulare Medizin (MDC), Berlin, Germany
| | | | - Fabio L Fernandes-Rosa
- INSERM, UMRS_970, Paris Cardiovascular Research Center, Paris, France.,Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Sheerazed Boulkroun
- INSERM, UMRS_970, Paris Cardiovascular Research Center, Paris, France.,Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Maria-Christina Zennaro
- INSERM, UMRS_970, Paris Cardiovascular Research Center, Paris, France.,Université Paris Descartes, Sorbonne Paris Cité, Paris, France.,Assistance Publique-Hôpitaux de Paris, Hôpital Européen Georges Pompidou, Service de Génétique, Paris, France
| | - Thomas J Jentsch
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany. .,Max-Delbrück-Centrum für Molekulare Medizin (MDC), Berlin, Germany. .,NeuroCure Cluster of Excellence, Charité Universitätsmedizin Berlin, Berlin, Germany.
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38
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Du C, Liu J, Wan H, Dong H, Zhao X. Functional Role of Basolateral ClC-2 Channels in the Regulation of Duodenal Anion Secretion in Mice. Dig Dis Sci 2019; 64:2527-2537. [PMID: 30874987 DOI: 10.1007/s10620-019-05578-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Accepted: 03/05/2019] [Indexed: 12/09/2022]
Abstract
BACKGROUND Although ClC-2 channels are important in colonic Cl- secretion, it is unclear about their roles in small intestinal anion secretion. Therefore, we sought to examine whether ClC-2 channels play important roles in anion secretion, particularly duodenal bicarbonate secretion (DBS). METHODS Duodenal mucosae from mice were stripped of seromuscular layers and mounted in Ussing chambers. Both duodenal short-circuit current (Isc) and HCO3- secretion in vitro were simultaneously recorded. DBS in vivo was measured by a CO2-sensitive electrode. RESULTS Lubiprostone, a selective ClC-2 activator, concentration-dependently increased both duodenal Isc and DBS only when applied basolaterally, but not when applied apically. Removal of extracellular Cl- abolished lubiprostone-induced duodenal Isc, but did not alter HCO3- secretion even in the presence of DIDS, a Cl-/HCO3- exchanger inhibitor. However, further addition of glibenclamide, a CFTR channel blocker, abolished lubiprostone-evoked HCO3- secretion. Moreover, lubiprostone-induced HCO3- secretion was impaired in CFTR-/- mice compared to wild-type littermates. Luminal perfusion of duodenal lumen with lubiprostone did not alter basal DBS in vivo, but lubiprostone (i.p.) was able to induce DBS, which was also significantly inhibited by Cd2+, a ClC-2 channel blocker. [Ca2+]cyt level, Ca2+-activated K+ channel- and cAMP-mediated duodenal Isc, and HCO3- secretion were unchanged by lubiprostone. CONCLUSIONS We have provided the first evidence for the novel functional role of basolateral ClC-2 channels in the regulation of duodenal anion secretion.
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Affiliation(s)
- Chao Du
- Department of Gastroenterology, Xinqiao Hospital, Army Medical University, Chongqing, 400037, China
| | - Jingjing Liu
- Department of Gastroenterology, Xinqiao Hospital, Army Medical University, Chongqing, 400037, China
| | - Hanxing Wan
- Department of Gastroenterology, Xinqiao Hospital, Army Medical University, Chongqing, 400037, China
| | - Hui Dong
- Department of Gastroenterology, Xinqiao Hospital, Army Medical University, Chongqing, 400037, China. .,Department of Medicine, School of Medicine, University of California, San Diego, CA, 92093, USA.
| | - Xiaoyan Zhao
- Department of Gastroenterology, Xinqiao Hospital, Army Medical University, Chongqing, 400037, China.
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39
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Nicoli ER, Weston MR, Hackbarth M, Becerril A, Larson A, Zein WM, Baker PR, Burke JD, Dorward H, Davids M, Huang Y, Adams DR, Zerfas PM, Chen D, Markello TC, Toro C, Wood T, Elliott G, Vu M, Zheng W, Garrett LJ, Tifft CJ, Gahl WA, Day-Salvatore DL, Mindell JA, Malicdan MCV. Lysosomal Storage and Albinism Due to Effects of a De Novo CLCN7 Variant on Lysosomal Acidification. Am J Hum Genet 2019; 104:1127-1138. [PMID: 31155284 PMCID: PMC6562152 DOI: 10.1016/j.ajhg.2019.04.008] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Accepted: 04/10/2019] [Indexed: 12/15/2022] Open
Abstract
Optimal lysosome function requires maintenance of an acidic pH maintained by proton pumps in combination with a counterion transporter such as the Cl-/H+ exchanger, CLCN7 (ClC-7), encoded by CLCN7. The role of ClC-7 in maintaining lysosomal pH has been controversial. In this paper, we performed clinical and genetic evaluations of two children of different ethnicities. Both children had delayed myelination and development, organomegaly, and hypopigmentation, but neither had osteopetrosis. Whole-exome and -genome sequencing revealed a de novo c.2144A>G variant in CLCN7 in both affected children. This p.Tyr715Cys variant, located in the C-terminal domain of ClC-7, resulted in increased outward currents when it was heterologously expressed in Xenopus oocytes. Fibroblasts from probands displayed a lysosomal pH approximately 0.2 units lower than that of control cells, and treatment with chloroquine normalized the pH. Primary fibroblasts from both probands also exhibited markedly enlarged intracellular vacuoles; this finding was recapitulated by the overexpression of human p.Tyr715Cys CLCN7 in control fibroblasts, reflecting the dominant, gain-of-function nature of the variant. A mouse harboring the knock-in Clcn7 variant exhibited hypopigmentation, hepatomegaly resulting from abnormal storage, and enlarged vacuoles in cultured fibroblasts. Our results show that p.Tyr715Cys is a gain-of-function CLCN7 variant associated with developmental delay, organomegaly, and hypopigmentation resulting from lysosomal hyperacidity, abnormal storage, and enlarged intracellular vacuoles. Our data supports the hypothesis that the ClC-7 antiporter plays a critical role in maintaining lysosomal pH.
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Affiliation(s)
- Elena-Raluca Nicoli
- Undiagnosed Diseases Program, National Human Genome Research Institute (NHGRI), National Institutes of Health (NIH), Bethesda, MD 20892, USA; Common Fund, Office of the Director, NIH, Bethesda, MD 20892, USA
| | - Mary R Weston
- Membrane Transport Biophysics Section, National Institute of Neurological Disorders and Stroke, NIH, Bethesda, MD 20892, USA
| | - Mary Hackbarth
- Undiagnosed Diseases Program, National Human Genome Research Institute (NHGRI), National Institutes of Health (NIH), Bethesda, MD 20892, USA; Common Fund, Office of the Director, NIH, Bethesda, MD 20892, USA
| | - Alissa Becerril
- Membrane Transport Biophysics Section, National Institute of Neurological Disorders and Stroke, NIH, Bethesda, MD 20892, USA
| | - Austin Larson
- Section of Genetics, Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Wadih M Zein
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, NIH, Bethesda, MD 20892, USA
| | - Peter R Baker
- Section of Genetics, Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - John Douglas Burke
- Human Biochemical Genetics Section, National Human Genome Research Institute, NIH, Bethesda, MD 20892, USA
| | - Heidi Dorward
- Human Biochemical Genetics Section, National Human Genome Research Institute, NIH, Bethesda, MD 20892, USA
| | - Mariska Davids
- Undiagnosed Diseases Program, National Human Genome Research Institute (NHGRI), National Institutes of Health (NIH), Bethesda, MD 20892, USA; Common Fund, Office of the Director, NIH, Bethesda, MD 20892, USA
| | - Yan Huang
- Undiagnosed Diseases Program, National Human Genome Research Institute (NHGRI), National Institutes of Health (NIH), Bethesda, MD 20892, USA; Common Fund, Office of the Director, NIH, Bethesda, MD 20892, USA
| | - David R Adams
- Undiagnosed Diseases Program, National Human Genome Research Institute (NHGRI), National Institutes of Health (NIH), Bethesda, MD 20892, USA; Common Fund, Office of the Director, NIH, Bethesda, MD 20892, USA; Office of the Clinical Director, National Human Genome Research Institute, NIH, Bethesda, MD 20892, USA
| | - Patricia M Zerfas
- Diagnostic and Research Services Branch, Office of Research Services, NIH, Bethesda, MD 20892, USA
| | - Dong Chen
- Division of Hematopathology, Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN 55905, USA
| | - Thomas C Markello
- Undiagnosed Diseases Program, National Human Genome Research Institute (NHGRI), National Institutes of Health (NIH), Bethesda, MD 20892, USA; Common Fund, Office of the Director, NIH, Bethesda, MD 20892, USA; Office of the Clinical Director, National Human Genome Research Institute, NIH, Bethesda, MD 20892, USA
| | - Camilo Toro
- Undiagnosed Diseases Program, National Human Genome Research Institute (NHGRI), National Institutes of Health (NIH), Bethesda, MD 20892, USA; Common Fund, Office of the Director, NIH, Bethesda, MD 20892, USA; Office of the Clinical Director, National Human Genome Research Institute, NIH, Bethesda, MD 20892, USA
| | - Tim Wood
- Metabolic Laboratory, Greenwood Genetic Center, Greenwood, SC 29646, USA
| | - Gene Elliott
- Embryonic Stem Cell and Transgenic Mouse Core, National Human Genome Research Institute, NIH, Bethesda, MD 20892, USA
| | - Mylinh Vu
- National Center for Translational Science, NIH, Rockville, MD 20850, USA
| | - Wei Zheng
- National Center for Translational Science, NIH, Rockville, MD 20850, USA
| | - Lisa J Garrett
- Embryonic Stem Cell and Transgenic Mouse Core, National Human Genome Research Institute, NIH, Bethesda, MD 20892, USA
| | - Cynthia J Tifft
- Undiagnosed Diseases Program, National Human Genome Research Institute (NHGRI), National Institutes of Health (NIH), Bethesda, MD 20892, USA; Common Fund, Office of the Director, NIH, Bethesda, MD 20892, USA; Office of the Clinical Director, National Human Genome Research Institute, NIH, Bethesda, MD 20892, USA
| | - William A Gahl
- Undiagnosed Diseases Program, National Human Genome Research Institute (NHGRI), National Institutes of Health (NIH), Bethesda, MD 20892, USA; Common Fund, Office of the Director, NIH, Bethesda, MD 20892, USA; Human Biochemical Genetics Section, National Human Genome Research Institute, NIH, Bethesda, MD 20892, USA; Office of the Clinical Director, National Human Genome Research Institute, NIH, Bethesda, MD 20892, USA
| | - Debra L Day-Salvatore
- Department of Medical Genetics and Genomic Medicine, Saint Peter's University Hospital, New Brunswick, NJ 08901, USA
| | - Joseph A Mindell
- Membrane Transport Biophysics Section, National Institute of Neurological Disorders and Stroke, NIH, Bethesda, MD 20892, USA.
| | - May Christine V Malicdan
- Undiagnosed Diseases Program, National Human Genome Research Institute (NHGRI), National Institutes of Health (NIH), Bethesda, MD 20892, USA; Common Fund, Office of the Director, NIH, Bethesda, MD 20892, USA; Human Biochemical Genetics Section, National Human Genome Research Institute, NIH, Bethesda, MD 20892, USA; Office of the Clinical Director, National Human Genome Research Institute, NIH, Bethesda, MD 20892, USA.
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Pathogenesis of Familial Hyperaldosteronism Type II: New Concepts Involving Anion Channels. Curr Hypertens Rep 2019; 21:31. [PMID: 30949771 DOI: 10.1007/s11906-019-0934-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
PURPOSE OF REVIEW The application of advanced genetic techniques has recently begun to unravel the genetic basis for familial primary aldosteronism type 2 (FH-II). RECENT FINDINGS Whole-exome sequencing in a large family with FH-II revealed a shared rare damaging heterozygous variant in CLCN2 (chr.3: g.184075850C>T, p.Arg172Gln) in three severely affected members. The gene encodes a chloride channel, ClC-2. A cohort of 80 unrelated individuals diagnosed with early-onset primary aldosteronism was also examined for CLCN2 mutations finding three further occurrences of p.Arg172Gln mutations and four single cases of other potentially damaging heterozygous mutations for an overall prevalence of 9.9%. A concurrent report also found a different CLCN2 mutation (p.Gly24Asp) in a single severely affected patient from a cohort of 12 with early-onset PA for a prevalence of 8.3%. Cases of primary aldosteronism associated with CLCN2 mutations appear to be bilateral and respond well to medical treatment. In the adrenal, ClC-2 has been demonstrated to localize predominantly to the zona glomerulosa (ZG), and functional analysis suggests that mutations in ClC-2 predispose ZG cells to depolarization, thus leading to calcium influx via activation of voltage-gated calcium channels and increased aldosterone production. Germline CLCN2 mutations appear to account for a substantial proportion of early-onset primary aldosteronism cases, and genetic testing for mutations in this gene should be considered in appropriate cases.
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Elorza-Vidal X, Gaitán-Peñas H, Estévez R. Chloride Channels in Astrocytes: Structure, Roles in Brain Homeostasis and Implications in Disease. Int J Mol Sci 2019; 20:ijms20051034. [PMID: 30818802 PMCID: PMC6429410 DOI: 10.3390/ijms20051034] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Revised: 02/15/2019] [Accepted: 02/17/2019] [Indexed: 12/29/2022] Open
Abstract
Astrocytes are the most abundant cell type in the CNS (central nervous system). They exert multiple functions during development and in the adult CNS that are essential for brain homeostasis. Both cation and anion channel activities have been identified in astrocytes and it is believed that they play key roles in astrocyte function. Whereas the proteins and the physiological roles assigned to cation channels are becoming very clear, the study of astrocytic chloride channels is in its early stages. In recent years, we have moved from the identification of chloride channel activities present in astrocyte primary culture to the identification of the proteins involved in these activities, the determination of their 3D structure and attempts to gain insights about their physiological role. Here, we review the recent findings related to the main chloride channels identified in astrocytes: the voltage-dependent ClC-2, the calcium-activated bestrophin, the volume-activated VRAC (volume-regulated anion channel) and the stress-activated Maxi-Cl−. We discuss key aspects of channel biophysics and structure with a focus on their role in glial physiology and human disease.
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Affiliation(s)
- Xabier Elorza-Vidal
- Unitat de Fisiologia, Departament de Ciències Fisiològiques, Genes Disease and Therapy Program IDIBELL-Institute of Neurosciences, Universitat de Barcelona, L'Hospitalet de Llobregat, 08907 Barcelona, Spain.
- Centro de Investigación en red de enfermedades raras (CIBERER), ISCIII, 08907 Barcelona, Spain.
| | - Héctor Gaitán-Peñas
- Unitat de Fisiologia, Departament de Ciències Fisiològiques, Genes Disease and Therapy Program IDIBELL-Institute of Neurosciences, Universitat de Barcelona, L'Hospitalet de Llobregat, 08907 Barcelona, Spain.
- Centro de Investigación en red de enfermedades raras (CIBERER), ISCIII, 08907 Barcelona, Spain.
| | - Raúl Estévez
- Unitat de Fisiologia, Departament de Ciències Fisiològiques, Genes Disease and Therapy Program IDIBELL-Institute of Neurosciences, Universitat de Barcelona, L'Hospitalet de Llobregat, 08907 Barcelona, Spain.
- Centro de Investigación en red de enfermedades raras (CIBERER), ISCIII, 08907 Barcelona, Spain.
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Okada Y, Okada T, Sato-Numata K, Islam MR, Ando-Akatsuka Y, Numata T, Kubo M, Shimizu T, Kurbannazarova RS, Marunaka Y, Sabirov RZ. Cell Volume-Activated and Volume-Correlated Anion Channels in Mammalian Cells: Their Biophysical, Molecular, and Pharmacological Properties. Pharmacol Rev 2019; 71:49-88. [PMID: 30573636 DOI: 10.1124/pr.118.015917] [Citation(s) in RCA: 57] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
There are a number of mammalian anion channel types associated with cell volume changes. These channel types are classified into two groups: volume-activated anion channels (VAACs) and volume-correlated anion channels (VCACs). VAACs can be directly activated by cell swelling and include the volume-sensitive outwardly rectifying anion channel (VSOR), which is also called the volume-regulated anion channel; the maxi-anion channel (MAC or Maxi-Cl); and the voltage-gated anion channel, chloride channel (ClC)-2. VCACs can be facultatively implicated in, although not directly activated by, cell volume changes and include the cAMP-activated cystic fibrosis transmembrane conductance regulator (CFTR) anion channel, the Ca2+-activated Cl- channel (CaCC), and the acid-sensitive (or acid-stimulated) outwardly rectifying anion channel. This article describes the phenotypical properties and activation mechanisms of both groups of anion channels, including accumulating pieces of information on the basis of recent molecular understanding. To that end, this review also highlights the molecular identities of both anion channel groups; in addition to the molecular identities of ClC-2 and CFTR, those of CaCC, VSOR, and Maxi-Cl were recently identified by applying genome-wide approaches. In the last section of this review, the most up-to-date information on the pharmacological properties of both anion channel groups, especially their half-maximal inhibitory concentrations (IC50 values) and voltage-dependent blocking, is summarized particularly from the standpoint of pharmacological distinctions among them. Future physiologic and pharmacological studies are definitely warranted for therapeutic targeting of dysfunction of VAACs and VCACs.
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Affiliation(s)
- Yasunobu Okada
- Departments of Physiology and Systems Bioscience (Y.O.) and Molecular Cell Physiology (Y.M.), Kyoto Prefectural University of Medicine, Kyoto, Japan; Division of Cell Signaling, National Institute for Physiological Sciences, Okazaki, Japan (Y.O., T.O., M.R.I., M.K., R.Z.S.); Department of Physiology, School of Medicine, Fukuoka University, Fukuoka, Japan (K.S.-N., T.N.); Department of Cell Physiology, Faculty of Pharmaceutical Sciences, Suzuka University of Medical Science, Suzuka, Japan (Y.A.-A.); Department of Pharmaceutical Physiology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan (T.S.); Laboratory of Molecular Physiology, Institute of Bioorganic Chemistry, Academy of Sciences of Uzbekistan, Tashkent, Uzbekistan (R.S.K., R.Z.S.); and Research Institute for Clinical Physiology, Kyoto Industrial Health Association, Kyoto, Japan (Y.M.)
| | - Toshiaki Okada
- Departments of Physiology and Systems Bioscience (Y.O.) and Molecular Cell Physiology (Y.M.), Kyoto Prefectural University of Medicine, Kyoto, Japan; Division of Cell Signaling, National Institute for Physiological Sciences, Okazaki, Japan (Y.O., T.O., M.R.I., M.K., R.Z.S.); Department of Physiology, School of Medicine, Fukuoka University, Fukuoka, Japan (K.S.-N., T.N.); Department of Cell Physiology, Faculty of Pharmaceutical Sciences, Suzuka University of Medical Science, Suzuka, Japan (Y.A.-A.); Department of Pharmaceutical Physiology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan (T.S.); Laboratory of Molecular Physiology, Institute of Bioorganic Chemistry, Academy of Sciences of Uzbekistan, Tashkent, Uzbekistan (R.S.K., R.Z.S.); and Research Institute for Clinical Physiology, Kyoto Industrial Health Association, Kyoto, Japan (Y.M.)
| | - Kaori Sato-Numata
- Departments of Physiology and Systems Bioscience (Y.O.) and Molecular Cell Physiology (Y.M.), Kyoto Prefectural University of Medicine, Kyoto, Japan; Division of Cell Signaling, National Institute for Physiological Sciences, Okazaki, Japan (Y.O., T.O., M.R.I., M.K., R.Z.S.); Department of Physiology, School of Medicine, Fukuoka University, Fukuoka, Japan (K.S.-N., T.N.); Department of Cell Physiology, Faculty of Pharmaceutical Sciences, Suzuka University of Medical Science, Suzuka, Japan (Y.A.-A.); Department of Pharmaceutical Physiology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan (T.S.); Laboratory of Molecular Physiology, Institute of Bioorganic Chemistry, Academy of Sciences of Uzbekistan, Tashkent, Uzbekistan (R.S.K., R.Z.S.); and Research Institute for Clinical Physiology, Kyoto Industrial Health Association, Kyoto, Japan (Y.M.)
| | - Md Rafiqul Islam
- Departments of Physiology and Systems Bioscience (Y.O.) and Molecular Cell Physiology (Y.M.), Kyoto Prefectural University of Medicine, Kyoto, Japan; Division of Cell Signaling, National Institute for Physiological Sciences, Okazaki, Japan (Y.O., T.O., M.R.I., M.K., R.Z.S.); Department of Physiology, School of Medicine, Fukuoka University, Fukuoka, Japan (K.S.-N., T.N.); Department of Cell Physiology, Faculty of Pharmaceutical Sciences, Suzuka University of Medical Science, Suzuka, Japan (Y.A.-A.); Department of Pharmaceutical Physiology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan (T.S.); Laboratory of Molecular Physiology, Institute of Bioorganic Chemistry, Academy of Sciences of Uzbekistan, Tashkent, Uzbekistan (R.S.K., R.Z.S.); and Research Institute for Clinical Physiology, Kyoto Industrial Health Association, Kyoto, Japan (Y.M.)
| | - Yuhko Ando-Akatsuka
- Departments of Physiology and Systems Bioscience (Y.O.) and Molecular Cell Physiology (Y.M.), Kyoto Prefectural University of Medicine, Kyoto, Japan; Division of Cell Signaling, National Institute for Physiological Sciences, Okazaki, Japan (Y.O., T.O., M.R.I., M.K., R.Z.S.); Department of Physiology, School of Medicine, Fukuoka University, Fukuoka, Japan (K.S.-N., T.N.); Department of Cell Physiology, Faculty of Pharmaceutical Sciences, Suzuka University of Medical Science, Suzuka, Japan (Y.A.-A.); Department of Pharmaceutical Physiology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan (T.S.); Laboratory of Molecular Physiology, Institute of Bioorganic Chemistry, Academy of Sciences of Uzbekistan, Tashkent, Uzbekistan (R.S.K., R.Z.S.); and Research Institute for Clinical Physiology, Kyoto Industrial Health Association, Kyoto, Japan (Y.M.)
| | - Tomohiro Numata
- Departments of Physiology and Systems Bioscience (Y.O.) and Molecular Cell Physiology (Y.M.), Kyoto Prefectural University of Medicine, Kyoto, Japan; Division of Cell Signaling, National Institute for Physiological Sciences, Okazaki, Japan (Y.O., T.O., M.R.I., M.K., R.Z.S.); Department of Physiology, School of Medicine, Fukuoka University, Fukuoka, Japan (K.S.-N., T.N.); Department of Cell Physiology, Faculty of Pharmaceutical Sciences, Suzuka University of Medical Science, Suzuka, Japan (Y.A.-A.); Department of Pharmaceutical Physiology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan (T.S.); Laboratory of Molecular Physiology, Institute of Bioorganic Chemistry, Academy of Sciences of Uzbekistan, Tashkent, Uzbekistan (R.S.K., R.Z.S.); and Research Institute for Clinical Physiology, Kyoto Industrial Health Association, Kyoto, Japan (Y.M.)
| | - Machiko Kubo
- Departments of Physiology and Systems Bioscience (Y.O.) and Molecular Cell Physiology (Y.M.), Kyoto Prefectural University of Medicine, Kyoto, Japan; Division of Cell Signaling, National Institute for Physiological Sciences, Okazaki, Japan (Y.O., T.O., M.R.I., M.K., R.Z.S.); Department of Physiology, School of Medicine, Fukuoka University, Fukuoka, Japan (K.S.-N., T.N.); Department of Cell Physiology, Faculty of Pharmaceutical Sciences, Suzuka University of Medical Science, Suzuka, Japan (Y.A.-A.); Department of Pharmaceutical Physiology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan (T.S.); Laboratory of Molecular Physiology, Institute of Bioorganic Chemistry, Academy of Sciences of Uzbekistan, Tashkent, Uzbekistan (R.S.K., R.Z.S.); and Research Institute for Clinical Physiology, Kyoto Industrial Health Association, Kyoto, Japan (Y.M.)
| | - Takahiro Shimizu
- Departments of Physiology and Systems Bioscience (Y.O.) and Molecular Cell Physiology (Y.M.), Kyoto Prefectural University of Medicine, Kyoto, Japan; Division of Cell Signaling, National Institute for Physiological Sciences, Okazaki, Japan (Y.O., T.O., M.R.I., M.K., R.Z.S.); Department of Physiology, School of Medicine, Fukuoka University, Fukuoka, Japan (K.S.-N., T.N.); Department of Cell Physiology, Faculty of Pharmaceutical Sciences, Suzuka University of Medical Science, Suzuka, Japan (Y.A.-A.); Department of Pharmaceutical Physiology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan (T.S.); Laboratory of Molecular Physiology, Institute of Bioorganic Chemistry, Academy of Sciences of Uzbekistan, Tashkent, Uzbekistan (R.S.K., R.Z.S.); and Research Institute for Clinical Physiology, Kyoto Industrial Health Association, Kyoto, Japan (Y.M.)
| | - Ranohon S Kurbannazarova
- Departments of Physiology and Systems Bioscience (Y.O.) and Molecular Cell Physiology (Y.M.), Kyoto Prefectural University of Medicine, Kyoto, Japan; Division of Cell Signaling, National Institute for Physiological Sciences, Okazaki, Japan (Y.O., T.O., M.R.I., M.K., R.Z.S.); Department of Physiology, School of Medicine, Fukuoka University, Fukuoka, Japan (K.S.-N., T.N.); Department of Cell Physiology, Faculty of Pharmaceutical Sciences, Suzuka University of Medical Science, Suzuka, Japan (Y.A.-A.); Department of Pharmaceutical Physiology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan (T.S.); Laboratory of Molecular Physiology, Institute of Bioorganic Chemistry, Academy of Sciences of Uzbekistan, Tashkent, Uzbekistan (R.S.K., R.Z.S.); and Research Institute for Clinical Physiology, Kyoto Industrial Health Association, Kyoto, Japan (Y.M.)
| | - Yoshinori Marunaka
- Departments of Physiology and Systems Bioscience (Y.O.) and Molecular Cell Physiology (Y.M.), Kyoto Prefectural University of Medicine, Kyoto, Japan; Division of Cell Signaling, National Institute for Physiological Sciences, Okazaki, Japan (Y.O., T.O., M.R.I., M.K., R.Z.S.); Department of Physiology, School of Medicine, Fukuoka University, Fukuoka, Japan (K.S.-N., T.N.); Department of Cell Physiology, Faculty of Pharmaceutical Sciences, Suzuka University of Medical Science, Suzuka, Japan (Y.A.-A.); Department of Pharmaceutical Physiology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan (T.S.); Laboratory of Molecular Physiology, Institute of Bioorganic Chemistry, Academy of Sciences of Uzbekistan, Tashkent, Uzbekistan (R.S.K., R.Z.S.); and Research Institute for Clinical Physiology, Kyoto Industrial Health Association, Kyoto, Japan (Y.M.)
| | - Ravshan Z Sabirov
- Departments of Physiology and Systems Bioscience (Y.O.) and Molecular Cell Physiology (Y.M.), Kyoto Prefectural University of Medicine, Kyoto, Japan; Division of Cell Signaling, National Institute for Physiological Sciences, Okazaki, Japan (Y.O., T.O., M.R.I., M.K., R.Z.S.); Department of Physiology, School of Medicine, Fukuoka University, Fukuoka, Japan (K.S.-N., T.N.); Department of Cell Physiology, Faculty of Pharmaceutical Sciences, Suzuka University of Medical Science, Suzuka, Japan (Y.A.-A.); Department of Pharmaceutical Physiology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan (T.S.); Laboratory of Molecular Physiology, Institute of Bioorganic Chemistry, Academy of Sciences of Uzbekistan, Tashkent, Uzbekistan (R.S.K., R.Z.S.); and Research Institute for Clinical Physiology, Kyoto Industrial Health Association, Kyoto, Japan (Y.M.)
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Teulon J, Planelles G, Sepúlveda FV, Andrini O, Lourdel S, Paulais M. Renal Chloride Channels in Relation to Sodium Chloride Transport. Compr Physiol 2018; 9:301-342. [DOI: 10.1002/cphy.c180024] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Thomassen M, Hostrup M, Murphy RM, Cromer BA, Skovgaard C, Gunnarsson TP, Christensen PM, Bangsbo J. Abundance of ClC-1 chloride channel in human skeletal muscle: fiber type specific differences and effect of training. J Appl Physiol (1985) 2018; 125:470-478. [DOI: 10.1152/japplphysiol.01042.2017] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Cl− channel protein 1 (ClC-1) may be important for excitability and contractility in skeletal muscle, but ClC-1 abundance has not been examined in human muscle. The aim of the present study was to examine ClC-1 abundance in human skeletal muscle, including fiber type specific differences and the effect of exercise training. A commercially available antibody was tested with positive and negative control tissue, and it recognized specifically ClC-1 in the range from 100 to 150 kDa. Abundance of ClC-1 was 38% higher ( P < 0.01) in fast twitch Type IIa muscle fibers than in slow twitch Type I. Muscle ClC-1 abundance did not change with 4 wk of training consisting of 30 min cycling at 85% of maximal heart rate (HRmax) and 3 × 30-s all out sprints or during a 7-wk training period with 10–12 × 30 s uphill cycling and 4–5 × ~4 min cycling at 90%–95% of HRmax. ClC-1 abundance correlated negatively ( P < 0.01) with maximal oxygen consumption ( r = –0.552) and incremental exercise performance ( r = –0.546). In addition, trained cyclists had lower ( P < 0.01) ClC-1 abundance than lesser trained individuals. The present observations indicate that a low abundance of muscle ClC-1 may be beneficial for exercise performance, but the role of abundance and regulation of ClC-1 in skeletal muscle of humans with respect to exercise performance and trainability need to be elucidated. NEW & NOTEWORTHY Abundance of the Cl− channel protein 1 (ClC-1) chloride channel may be important for excitability and contractility in human skeletal muscle and may therefore have implications for fatigue development. In this study, we confirmed ClC-1 specificity for a commercially available antibody, and this study is first to our knowledge to determine ClC-1 protein abundance in human muscle by Western blotting. We observed that abundance of ClC-1 was higher in fast compared with slow twitch fibers and lower in trained individuals than in recreationally active.
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Affiliation(s)
- Martin Thomassen
- Section of Integrative Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Morten Hostrup
- Section of Integrative Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Robyn M. Murphy
- Department of Biochemistry & Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria, Australia
| | - Brett A. Cromer
- Department of Chemistry and Biotechnology, Swinburne University, Melbourne, Victoria, Australia
| | - Casper Skovgaard
- Section of Integrative Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Thomas P. Gunnarsson
- Section of Integrative Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Peter M. Christensen
- Section of Integrative Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Jens Bangsbo
- Section of Integrative Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
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Jentsch TJ, Pusch M. CLC Chloride Channels and Transporters: Structure, Function, Physiology, and Disease. Physiol Rev 2018; 98:1493-1590. [DOI: 10.1152/physrev.00047.2017] [Citation(s) in RCA: 214] [Impact Index Per Article: 35.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
CLC anion transporters are found in all phyla and form a gene family of eight members in mammals. Two CLC proteins, each of which completely contains an ion translocation parthway, assemble to homo- or heteromeric dimers that sometimes require accessory β-subunits for function. CLC proteins come in two flavors: anion channels and anion/proton exchangers. Structures of these two CLC protein classes are surprisingly similar. Extensive structure-function analysis identified residues involved in ion permeation, anion-proton coupling and gating and led to attractive biophysical models. In mammals, ClC-1, -2, -Ka/-Kb are plasma membrane Cl−channels, whereas ClC-3 through ClC-7 are 2Cl−/H+-exchangers in endolysosomal membranes. Biological roles of CLCs were mostly studied in mammals, but also in plants and model organisms like yeast and Caenorhabditis elegans. CLC Cl−channels have roles in the control of electrical excitability, extra- and intracellular ion homeostasis, and transepithelial transport, whereas anion/proton exchangers influence vesicular ion composition and impinge on endocytosis and lysosomal function. The surprisingly diverse roles of CLCs are highlighted by human and mouse disorders elicited by mutations in their genes. These pathologies include neurodegeneration, leukodystrophy, mental retardation, deafness, blindness, myotonia, hyperaldosteronism, renal salt loss, proteinuria, kidney stones, male infertility, and osteopetrosis. In this review, emphasis is laid on biophysical structure-function analysis and on the cell biological and organismal roles of mammalian CLCs and their role in disease.
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Affiliation(s)
- Thomas J. Jentsch
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP) and Max-Delbrück-Centrum für Molekulare Medizin (MDC), Berlin, Germany; and Istituto di Biofisica, Consiglio Nazionale delle Ricerche, Genova, Italy
| | - Michael Pusch
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP) and Max-Delbrück-Centrum für Molekulare Medizin (MDC), Berlin, Germany; and Istituto di Biofisica, Consiglio Nazionale delle Ricerche, Genova, Italy
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Lu J, Xu F, Zhang Y, Lu H, Zhang J. ClC-2 knockdown prevents cerebrovascular remodeling via inhibition of the Wnt/β-catenin signaling pathway. Cell Mol Biol Lett 2018; 23:29. [PMID: 29988306 PMCID: PMC6022329 DOI: 10.1186/s11658-018-0095-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Accepted: 06/19/2018] [Indexed: 02/05/2023] Open
Abstract
BACKGROUND Mishandling of intracellular chloride (Cl-) concentration ([Cl-]i) in cerebrovascular smooth muscle cells is implicated in several pathological processes, including hyperplasia and remodeling. We investigated the effects of ClC-2-mediated Cl- efflux on the proliferation of human brain vascular smooth muscle cells (HBVSMCs) induced by angiotensin II (AngII). METHODS Cell proliferation and motility were determined using the CCK-8, bromodeoxyuridine staining, wound healing and invasion assays. ClC-2, PCNA, Ki67, survivin and cyclin D1 expression, and β-catenin and GSK-3β phosphorylation were examined using western blotting. Histological analyses were performed using hematoxylin and eosin staining and α-SMA staining. RESULTS Our results showed that AngII-induced HBVSMC proliferation was accompanied by a decrease in [Cl-]i and an increase in ClC-2 expression. Inhibition of ClC-2 by siRNA prevented AngII from inducing the efflux of Cl-. AngII-induced HBVSMC proliferation, migration and invasion were significantly attenuated by ClC-2 downregulation. The inhibitory effects of ClC-2 knockout on HBVSMC proliferation and motility were associated with inactivation of the Wnt/β-catenin signaling pathway, as evidenced by inhibition of β-catenin phosphorylation and nuclear translocation, and decrease of GSK-3β phosphorylation and survivin and cyclin D1 expression. Recombinant Wnt3a treatment markedly reversed the effect of ClC-2 knockdown on HBVSMC viability. An in vivo study revealed that knockdown of ClC-2 with shRNA adenovirus ameliorated basilar artery remodeling by inhibiting Wnt/β-catenin signaling in AngII-treated mice. CONCLUSION This study demonstrates that blocking ClC-2-mediated Cl- efflux inhibits AngII-induced cerebrovascular smooth muscle cell proliferation and migration by inhibiting the Wnt/β-catenin pathway. Our data indicate that downregulation of ClC-2 may be a viable strategy in the prevention of hyperplasia and remodeling of cerebrovascular smooth muscle cells.
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Affiliation(s)
- Jingjing Lu
- Department of Neurology, Henan People’s Hospital, No. 7 Wai-5 Road, Zhengzhou, 450052 Henan Province China
| | - Feng Xu
- Department of Urology, First Affiliated Hospital, Zhengzhou University, Zhengzhou, China
| | - Yingna Zhang
- Institute of Medical and Pharmaceutical Sciences, Zhengzhou University, Zhengzhou, China
| | - Hong Lu
- Department of Neurology, First Affiliated Hospital, Zhengzhou University, Zhengzhou, 450052 Henan Province China
| | - Jiewen Zhang
- Department of Neurology, Henan People’s Hospital, No. 7 Wai-5 Road, Zhengzhou, 450052 Henan Province China
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47
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CLCN2 chloride channel mutations in familial hyperaldosteronism type II. Nat Genet 2018; 50:349-354. [PMID: 29403011 PMCID: PMC5862758 DOI: 10.1038/s41588-018-0048-5] [Citation(s) in RCA: 146] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Accepted: 12/20/2017] [Indexed: 12/31/2022]
Abstract
Primary aldosteronism, a common cause of severe hypertension1, features constitutive production of the adrenal steroid aldosterone. We analyzed a multiplex family with familial hyperaldosteronism type II (FH-II)2 and 80 additional probands with unsolved early-onset primary aldosteronism. Eight probands had novel heterozygous variants in CLCN2, including two de novo mutations and four independent occurrences of the identical p.Arg172Gln mutation; all relatives with early-onset primary aldosteronism carried the CLCN2 variant found in probands. CLCN2 encodes a voltage-gated chloride channel expressed in adrenal glomerulosa that opens at hyperpolarized membrane potentials. Channel opening depolarizes glomerulosa cells and induces expression of aldosterone synthase, the rate-limiting enzyme for aldosterone biosynthesis. Mutant channels cause gain of function, with higher open probabilities at the glomerulosa resting potential. These findings for the first time demonstrate a role of anion channels in glomerulosa membrane potential determination, aldosterone production and hypertension. They establish the cause of a substantial fraction of early-onset primary aldosteronism.
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48
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Fernandes-Rosa FL, Daniil G, Orozco IJ, Göppner C, El Zein R, Jain V, Boulkroun S, Jeunemaitre X, Amar L, Lefebvre H, Schwarzmayr T, Strom TM, Jentsch TJ, Zennaro MC. A gain-of-function mutation in the CLCN2 chloride channel gene causes primary aldosteronism. Nat Genet 2018; 50:355-361. [DOI: 10.1038/s41588-018-0053-8] [Citation(s) in RCA: 114] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Accepted: 01/03/2018] [Indexed: 11/09/2022]
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49
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Hou X, Zhang R, Wang J, Li Y, Li F, Zhang Y, Zheng X, Shen Y, Wang Y, Zhou L. CLC-2 is a positive modulator of oligodendrocyte precursor cell differentiation and myelination. Mol Med Rep 2018; 17:4515-4523. [PMID: 29344669 PMCID: PMC5802228 DOI: 10.3892/mmr.2018.8439] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Accepted: 12/18/2017] [Indexed: 01/20/2023] Open
Abstract
Oligodendrocytes (OLs) are myelin-forming cells that are present within the central nervous system. Impaired oligodendrocyte precursor cell (OPC) differentiation into mature OLs is a major cause of demyelination diseases. Therefore, identifying the underlying molecular mechanisms of OPC differentiation is crucial to understand the processes of myelination and demyelination. It has been acknowledged that various extrinsic and intrinsic factors are involved in the control of OPC differentiation; however, the function of ion channels, particularly the voltage-gated chloride channel (CLC), in OPC differentiation and myelination are not fully understood. The present study demonstrated that CLC-2 may be a positive modulator of OPC differentiation and myelination. Western blotting results revealed that CLC-2 was expressed in both OPCs and OLs. Furthermore, CLC-2 currents (ICLC-2) were recorded in both types of cells. The inhibition of ICLC-2 by GaTx2, a blocker of CLC-2, was demonstrated to be higher in OPCs compared with OLs, indicating that CLC-2 may serve a role in OL differentiation. The results of western blotting and immunofluorescence staining also demonstrated that the expression levels of myelin basic protein were reduced following GaTx2 treatment, indicating that the differentiation of OPCs into OLs was inhibited following CLC-2 inhibition. In addition, following western blot analysis, it was also demonstrated that the protein expression of the myelin proteins yin yang 1, myelin regulatory factor, Smad-interacting protein 1 and sex-determining region Y-box 10 were regulated by CLC-2 inhibition. Taken together, the results of the present study indicate that CLC-2 may be a positive regulator of OPC differentiation and able to contribute to myelin formation and repair in myelin-associated diseases by controlling the number and open state of CLC-2 channels.
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Affiliation(s)
- Xiaolin Hou
- Department of Neurology, General Hospital of Ningxia Medical University, Yinchuan, Ningxia 750004, P.R. China
| | - Rui Zhang
- Ningxia Key Laboratory of Cerebrocranial Diseases, Basic Medical School of Ningxia Medical University, Yinchuan, Ningxia 750004, P.R. China
| | - Junyan Wang
- Ningxia Key Laboratory of Cerebrocranial Diseases, Basic Medical School of Ningxia Medical University, Yinchuan, Ningxia 750004, P.R. China
| | - Yunhong Li
- Ningxia Key Laboratory of Cerebrocranial Diseases, Basic Medical School of Ningxia Medical University, Yinchuan, Ningxia 750004, P.R. China
| | - Fan Li
- Ningxia Key Laboratory of Cerebrocranial Diseases, Basic Medical School of Ningxia Medical University, Yinchuan, Ningxia 750004, P.R. China
| | - Yan Zhang
- Ningxia Key Laboratory of Cerebrocranial Diseases, Basic Medical School of Ningxia Medical University, Yinchuan, Ningxia 750004, P.R. China
| | - Xiaomin Zheng
- Ningxia Key Laboratory of Cerebrocranial Diseases, Basic Medical School of Ningxia Medical University, Yinchuan, Ningxia 750004, P.R. China
| | - Ying Shen
- Department of Neurobiology, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, P.R. China
| | - Yin Wang
- Ningxia Key Laboratory of Cerebrocranial Diseases, Basic Medical School of Ningxia Medical University, Yinchuan, Ningxia 750004, P.R. China
| | - Liang Zhou
- Department of Neurobiology, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, P.R. China
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50
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Wang H, Xu M, Kong Q, Sun P, Yan F, Tian W, Wang X. Research and progress on ClC‑2 (Review). Mol Med Rep 2017; 16:11-22. [PMID: 28534947 PMCID: PMC5482133 DOI: 10.3892/mmr.2017.6600] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Accepted: 02/13/2017] [Indexed: 12/22/2022] Open
Abstract
Chloride channel 2 (ClC-2) is one of the nine mammalian members of the ClC family. The present review discusses the molecular properties of ClC‑2, including CLCN2, ClC‑2 promoter and the structural properties of ClC‑2 protein; physiological properties; functional properties, including the regulation of cell volume. The effects of ClC‑2 on the digestive, respiratory, circulatory, nervous and optical systems are also discussed, in addition to the mechanisms involved in the regulation of ClC‑2. The review then discusses the diseases associated with ClC‑2, including degeneration of the retina, Sjögren's syndrome, age‑related cataracts, degeneration of the testes, azoospermia, lung cancer, constipation, repair of impaired intestinal mucosa barrier, leukemia, cystic fibrosis, leukoencephalopathy, epilepsy and diabetes mellitus. It was concluded that future investigations of ClC‑2 are likely to be focused on developing specific drugs, activators and inhibitors regulating the expression of ClC‑2 to treat diseases associated with ClC‑2. The determination of CLCN2 is required to prevent and treat several diseases associated with ClC‑2.
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Affiliation(s)
- Hongwei Wang
- Department of Ophthalmology, People's Hospital of Jingjiang, Jingjiang, Jiangsu 214500, P.R. China
| | - Minghui Xu
- Library, Qiqihar Medical University, Qiqihar, Heilongjiang 161006, P.R. China
| | - Qingjie Kong
- School of Computer Science and Information Technology, Northeast Normal University, Changchun, Jilin 130024, P.R. China
| | - Peng Sun
- Department of Ophthalmology, The First Affiliated Hospital of Jiamusi University, Jiamusi, Heilongjiang 154000, P.R. China
| | - Fengyun Yan
- Assets Division, Harbin University of Science and Technology, Harbin, Heilongjiang 150080, P.R. China
| | - Wenying Tian
- Library, Qiqihar Medical University, Qiqihar, Heilongjiang 161006, P.R. China
| | - Xin Wang
- Library, Qiqihar Medical University, Qiqihar, Heilongjiang 161006, P.R. China
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