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Jian L, Zhang Q, Yao D, Wang Q, Chen M, Xia Y, Li S, Shen Y, Cao M, Qin A, Li L, Cao Y. The structural insight into the functional modulation of human anion exchanger 3. Nat Commun 2024; 15:6134. [PMID: 39033175 PMCID: PMC11271275 DOI: 10.1038/s41467-024-50572-x] [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: 02/20/2024] [Accepted: 07/15/2024] [Indexed: 07/23/2024] Open
Abstract
Anion exchanger 3 (AE3) is pivotal in regulating intracellular pH across excitable tissues, yet its structural intricacies and functional dynamics remain underexplored compared to other anion exchangers. This study unveils the structural insights into human AE3, including the cryo-electron microscopy structures for AE3 transmembrane domains (TMD) and a chimera combining AE3 N-terminal domain (NTD) with AE2 TMD (hAE3NTD2TMD). Our analyzes reveal a substrate binding site, an NTD-TMD interlock mechanism, and a preference for an outward-facing conformation. Unlike AE2, which has more robust acid-loading capabilities, AE3's structure, including a less stable inward-facing conformation due to missing key NTD-TMD interactions, contributes to its moderated pH-modulating activity and increased sensitivity to the inhibitor DIDS. These structural differences underline AE3's distinct functional roles in specific tissues and underscore the complex interplay between structural dynamics and functional specificity within the anion exchanger family, enhancing our understanding of the physiological and pathological roles of the anion exchanger family.
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Affiliation(s)
- Liyan Jian
- Department of Orthopaedics, Shanghai Key Laboratory of Orthopaedic Implant, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Institute of Precision Medicine, the Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, 115 Jinzun Road, Shanghai, China
| | - Qing Zhang
- Institute of Precision Medicine, the Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, 115 Jinzun Road, Shanghai, China
- Structural Biology Program, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY, USA
| | - Deqiang Yao
- Institute of Precision Medicine, the Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, 115 Jinzun Road, Shanghai, China
- Institute of Aging & Tissue Regeneration, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Qian Wang
- Institute of Precision Medicine, the Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, 115 Jinzun Road, Shanghai, China
| | - Moxin Chen
- Department of Ophthalmology, Shanghai Ninth People's Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- Shanghai Key Laboratory of Orbital Diseases and Ocular Oncology, Shanghai, China
| | - Ying Xia
- Institute of Precision Medicine, the Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, 115 Jinzun Road, Shanghai, China
| | - Shaobai Li
- Institute of Precision Medicine, the Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, 115 Jinzun Road, Shanghai, China
| | - Yafeng Shen
- Institute of Precision Medicine, the Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, 115 Jinzun Road, Shanghai, China
| | - Mi Cao
- Institute of Precision Medicine, the Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, 115 Jinzun Road, Shanghai, China
| | - An Qin
- Department of Orthopaedics, Shanghai Key Laboratory of Orthopaedic Implant, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
- Department of Orthopaedics, Shanghai Frontiers Science Center of Degeneration and Regeneration in Skeletal System, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
| | - Lin Li
- Department of Ophthalmology, Shanghai Ninth People's Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China.
- Shanghai Key Laboratory of Orbital Diseases and Ocular Oncology, Shanghai, China.
| | - Yu Cao
- Department of Orthopaedics, Shanghai Key Laboratory of Orthopaedic Implant, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
- Institute of Precision Medicine, the Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, 115 Jinzun Road, Shanghai, China.
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Johnsen LØ, Friis KA, Møller-Madsen MK, Damkier HH. Mechanisms of cerebrospinal fluid secretion by the choroid plexus epithelium: Application to various intracranial pathologies. Clin Anat 2024. [PMID: 38894645 DOI: 10.1002/ca.24199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2024] [Revised: 06/02/2024] [Accepted: 06/06/2024] [Indexed: 06/21/2024]
Abstract
The choroid plexus (CP) is a small yet highly active epithelial tissue located in the ventricles of the brain. It secretes most of the CSF that envelops the brain and spinal cord. The epithelial cells of the CP have a high fluid secretion rate and differ from many other secretory epithelia in the organization of several key ion transporters. One striking difference is the luminal location of, for example, the vital Na+-K+-ATPase. In recent years, there has been a renewed focus on the role of ion transporters in CP secretion. Several studies have indicated that increased membrane transport activity is implicated in disorders such as hydrocephalus, idiopathic intracranial hypertension, and posthemorrhagic sequelae. The importance of the CP membrane transporters in regulating the composition of the CSF has also been a focus in research in recent years, particularly as a regulator of breathing and hemodynamic parameters such as blood pressure. This review focuses on the role of the fundamental ion transporters involved in CSF secretion and its ion composition. It gives a brief overview of the established factors and controversies concerning ion transporters, and finally discusses future perspectives related to the role of these transporters in the CP epithelium.
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3
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Benko F, Urminská D, Ďuračka M, Tvrdá E. Signaling Roleplay between Ion Channels during Mammalian Sperm Capacitation. Biomedicines 2023; 11:2519. [PMID: 37760960 PMCID: PMC10525812 DOI: 10.3390/biomedicines11092519] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2023] [Revised: 08/31/2023] [Accepted: 09/06/2023] [Indexed: 09/29/2023] Open
Abstract
In order to accomplish their primary goal, mammalian spermatozoa must undergo a series of physiological, biochemical, and functional changes crucial for the acquisition of fertilization ability. Spermatozoa are highly polarized cells, which must swiftly respond to ionic changes on their passage through the female reproductive tract, and which are necessary for male gametes to acquire their functional competence. This review summarizes the current knowledge about specific ion channels and transporters located in the mammalian sperm plasma membrane, which are intricately involved in the initiation of changes within the ionic milieu of the sperm cell, leading to variations in the sperm membrane potential, membrane depolarization and hyperpolarization, changes in sperm motility and capacitation to further lead to the acrosome reaction and sperm-egg fusion. We also discuss the functionality of selected ion channels in male reproductive health and/or disease since these may become promising targets for clinical management of infertility in the future.
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Affiliation(s)
- Filip Benko
- Institute of Biotechnology, Faculty of Biotechnology and Food Sciences, Slovak University of Agriculture in Nitra, Tr. A. Hlinku 2, 949 76 Nitra, Slovakia; (D.U.); (E.T.)
| | - Dana Urminská
- Institute of Biotechnology, Faculty of Biotechnology and Food Sciences, Slovak University of Agriculture in Nitra, Tr. A. Hlinku 2, 949 76 Nitra, Slovakia; (D.U.); (E.T.)
| | - Michal Ďuračka
- AgroBioTech Research Centre, Slovak University of Agriculture in Nitra, Tr. A. Hlinku 2, 949 76 Nitra, Slovakia;
| | - Eva Tvrdá
- Institute of Biotechnology, Faculty of Biotechnology and Food Sciences, Slovak University of Agriculture in Nitra, Tr. A. Hlinku 2, 949 76 Nitra, Slovakia; (D.U.); (E.T.)
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4
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Rehman T, Welsh MJ. Inflammation as a Regulator of the Airway Surface Liquid pH in Cystic Fibrosis. Cells 2023; 12:1104. [PMID: 37190013 PMCID: PMC10137218 DOI: 10.3390/cells12081104] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Revised: 04/05/2023] [Accepted: 04/06/2023] [Indexed: 05/17/2023] Open
Abstract
The airway surface liquid (ASL) is a thin sheet of fluid that covers the luminal aspect of the airway epithelium. The ASL is a site of several first-line host defenses, and its composition is a key factor that determines respiratory fitness. Specifically, the acid-base balance of ASL has a major influence on the vital respiratory defense processes of mucociliary clearance and antimicrobial peptide activity against inhaled pathogens. In the inherited disorder cystic fibrosis (CF), loss of cystic fibrosis transmembrane conductance regulator (CFTR) anion channel function reduces HCO3- secretion, lowers the pH of ASL (pHASL), and impairs host defenses. These abnormalities initiate a pathologic process whose hallmarks are chronic infection, inflammation, mucus obstruction, and bronchiectasis. Inflammation is particularly relevant as it develops early in CF and persists despite highly effective CFTR modulator therapy. Recent studies show that inflammation may alter HCO3- and H+ secretion across the airway epithelia and thus regulate pHASL. Moreover, inflammation may enhance the restoration of CFTR channel function in CF epithelia exposed to clinically approved modulators. This review focuses on the complex relationships between acid-base secretion, airway inflammation, pHASL regulation, and therapeutic responses to CFTR modulators. These factors have important implications for defining optimal ways of tackling CF airway inflammation in the post-modulator era.
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Affiliation(s)
- Tayyab Rehman
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48109, USA
| | - Michael J. Welsh
- Departments of Internal Medicine and Molecular Physiology and Biophysics, Pappajohn Biomedical Institute, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
- Howard Hughes Medical Institute, University of Iowa, Iowa City, IA 52242, USA
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Pressey JC, de Saint-Rome M, Raveendran VA, Woodin MA. Chloride transporters controlling neuronal excitability. Physiol Rev 2023; 103:1095-1135. [PMID: 36302178 DOI: 10.1152/physrev.00025.2021] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Synaptic inhibition plays a crucial role in regulating neuronal excitability, which is the foundation of nervous system function. This inhibition is largely mediated by the neurotransmitters GABA and glycine that activate Cl--permeable ion channels, which means that the strength of inhibition depends on the Cl- gradient across the membrane. In neurons, the Cl- gradient is primarily mediated by two secondarily active cation-chloride cotransporters (CCCs), NKCC1 and KCC2. CCC-mediated regulation of the neuronal Cl- gradient is critical for healthy brain function, as dysregulation of CCCs has emerged as a key mechanism underlying neurological disorders including epilepsy, neuropathic pain, and autism spectrum disorder. This review begins with an overview of neuronal chloride transporters before explaining the dependent relationship between these CCCs, Cl- regulation, and inhibitory synaptic transmission. We then discuss the evidence for how CCCs can be regulated, including by activity and their protein interactions, which underlie inhibitory synaptic plasticity. For readers who may be interested in conducting experiments on CCCs and neuronal excitability, we have included a section on techniques for estimating and recording intracellular Cl-, including their advantages and limitations. Although the focus of this review is on neurons, we also examine how Cl- is regulated in glial cells, which in turn regulate neuronal excitability through the tight relationship between this nonneuronal cell type and synapses. Finally, we discuss the relatively extensive and growing literature on how CCC-mediated neuronal excitability contributes to neurological disorders.
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Affiliation(s)
- Jessica C Pressey
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada
| | - Miranda de Saint-Rome
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada
| | - Vineeth A Raveendran
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada
| | - Melanie A Woodin
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada
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Zhang Q, Jian L, Yao D, Rao B, Xia Y, Hu K, Li S, Shen Y, Cao M, Qin A, Zhao J, Cao Y. The structural basis of the pH-homeostasis mediated by the Cl -/HCO 3- exchanger, AE2. Nat Commun 2023; 14:1812. [PMID: 37002221 PMCID: PMC10066210 DOI: 10.1038/s41467-023-37557-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Accepted: 03/22/2023] [Indexed: 04/03/2023] Open
Abstract
The cell maintains its intracellular pH in a narrow physiological range and disrupting the pH-homeostasis could cause dysfunctional metabolic states. Anion exchanger 2 (AE2) works at high cellular pH to catalyze the exchange between the intracellular HCO3- and extracellular Cl-, thereby maintaining the pH-homeostasis. Here, we determine the cryo-EM structures of human AE2 in five major operating states and one transitional hybrid state. Among those states, the AE2 shows the inward-facing, outward-facing, and intermediate conformations, as well as the substrate-binding pockets at two sides of the cell membrane. Furthermore, critical structural features were identified showing an interlock mechanism for interactions among the cytoplasmic N-terminal domain and the transmembrane domain and the self-inhibitory effect of the C-terminal loop. The structural and cell-based functional assay collectively demonstrate the dynamic process of the anion exchange across membranes and provide the structural basis for the pH-sensitive pH-rebalancing activity of AE2.
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Affiliation(s)
- Qing Zhang
- Department of Orthopaedics, Shanghai Key Laboratory of Orthopaedic Implant, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, 200011, Shanghai, China
- Institute of Precision Medicine, the Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, 115 Jinzun Road, 200125, Shanghai, China
| | - Liyan Jian
- Department of Orthopaedics, Shanghai Key Laboratory of Orthopaedic Implant, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, 200011, Shanghai, China
- Department of Orthopaedics, Shanghai Frontiers Science Center of Degeneration and Regeneration in Skeletal System, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, 200011, Shanghai, China
| | - Deqiang Yao
- Institute of Precision Medicine, the Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, 115 Jinzun Road, 200125, Shanghai, China
- State Key Laboratory of Oncogenes and Related Genes, Ren Ji Hospital, Shanghai Jiao Tong University School of Medicine, 200127, Shanghai, China
| | - Bing Rao
- Department of Orthopaedics, Shanghai Key Laboratory of Orthopaedic Implant, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, 200011, Shanghai, China
- Institute of Precision Medicine, the Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, 115 Jinzun Road, 200125, Shanghai, China
| | - Ying Xia
- Institute of Precision Medicine, the Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, 115 Jinzun Road, 200125, Shanghai, China
| | - Kexin Hu
- Institute of Precision Medicine, the Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, 115 Jinzun Road, 200125, Shanghai, China
| | - Shaobai Li
- Institute of Precision Medicine, the Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, 115 Jinzun Road, 200125, Shanghai, China
| | - Yafeng Shen
- Institute of Precision Medicine, the Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, 115 Jinzun Road, 200125, Shanghai, China
| | - Mi Cao
- Institute of Precision Medicine, the Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, 115 Jinzun Road, 200125, Shanghai, China
| | - An Qin
- Department of Orthopaedics, Shanghai Key Laboratory of Orthopaedic Implant, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, 200011, Shanghai, China
- Department of Orthopaedics, Shanghai Frontiers Science Center of Degeneration and Regeneration in Skeletal System, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, 200011, Shanghai, China
| | - Jie Zhao
- Department of Orthopaedics, Shanghai Key Laboratory of Orthopaedic Implant, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, 200011, Shanghai, China
- Department of Orthopaedics, Shanghai Frontiers Science Center of Degeneration and Regeneration in Skeletal System, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, 200011, Shanghai, China
| | - Yu Cao
- Department of Orthopaedics, Shanghai Key Laboratory of Orthopaedic Implant, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, 200011, Shanghai, China.
- Institute of Precision Medicine, the Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, 115 Jinzun Road, 200125, Shanghai, China.
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Lee SK, Occhipinti R, Moss FJ, Parker MD, Grichtchenko II, Boron WF. Distinguishing among HCO 3- , CO 3= , and H + as Substrates of Proteins That Appear To Be "Bicarbonate" Transporters. J Am Soc Nephrol 2023; 34:40-54. [PMID: 36288904 PMCID: PMC10103014 DOI: 10.1681/asn.2022030289] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Accepted: 07/23/2022] [Indexed: 02/02/2023] Open
Abstract
BACKGROUND Differentiating among HCO 3- , CO 3= , and H + movements across membranes has long seemed impossible. We now seek to discriminate unambiguously among three alternate mechanisms: the inward flux of 2 HCO 3- (mechanism 1), the inward flux of 1 CO 3= (mechanism 2), and the CO 2 /HCO 3- -stimulated outward flux of 2 H + (mechanism 3). METHODS As a test case, we use electrophysiology and heterologous expression in Xenopus oocytes to examine SLC4 family members that appear to transport "bicarbonate" ("HCO 3- "). RESULTS First, we note that cell-surface carbonic anhydrase should catalyze the forward reaction CO 2 +OH - →HCO 3- if HCO 3- is the substrate; if it is not, the reverse reaction should occur. Monitoring changes in cell-surface pH ( Δ pH S ) with or without cell-surface carbonic anhydrase, we find that the presumed Cl-"HCO 3 " exchanger AE1 (SLC4A1) does indeed transport HCO 3- (mechanism 1) as long supposed, whereas the electrogenic Na/"HCO 3 " cotransporter NBCe1 (SLC4A4) and the electroneutral Na + -driven Cl-"HCO 3 " exchanger NDCBE (SLC4A8) do not. Second, we use mathematical simulations to show that each of the three mechanisms generates unique quantities of H + at the cell surface (measured as Δ pH S ) per charge transported (measured as change in membrane current, ΔIm ). Calibrating ΔpH S /Δ Im in oocytes expressing the H + channel H V 1, we find that our NBCe1 data align closely with predictions of CO 3= transport (mechanism 2), while ruling out HCO 3- (mechanism 1) and CO 2 /HCO 3- -stimulated H + transport (mechanism 3). CONCLUSIONS Our surface chemistry approach makes it possible for the first time to distinguish among HCO 3- , CO 3= , and H + fluxes, thereby providing insight into molecular actions of clinically relevant acid-base transporters and carbonic-anhydrase inhibitors.
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Affiliation(s)
- Seong-Ki Lee
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, Ohio
| | - Rossana Occhipinti
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, Ohio
| | - Fraser J. Moss
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, Ohio
| | - Mark D. Parker
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, Ohio
- Department of Physiology and Biophysics, University at Buffalo Jacobs School of Medicine and Biomedical Sciences, Buffalo, New York
| | | | - Walter F. Boron
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, Ohio
- Department of Medicine, Case Western Reserve University School of Medicine, Cleveland, Ohio
- Department of Biochemistry, Case Western Reserve University School of Medicine, Cleveland, Ohio
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Zhou C, Hu B, Tang Y, Chen X, Ma Z, Ding Q, Nie G. Genome-wide characterization of the Triplophysa dalaica slc4 gene family and expression profiles in response to salinity changes. BMC Genomics 2022; 23:824. [PMID: 36513970 PMCID: PMC9746111 DOI: 10.1186/s12864-022-09057-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Accepted: 11/29/2022] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND The solute carrier 4 (SLC4) gene family is involved in a variety of physiological processes in organisms and is essential for maintaining acid-base balance in the body. The slc4 genes have been extensively studied in mammals, and they play important roles in intracellular and extracellular pH regulation and in the secretion and uptake of HCO3- and other ions (Na+ and Cl-) between transepithelial cells in different tissues. This study identified and characterized the entire slc4 gene family of Triplophysa dalaica. RESULTS Fifteen slc4 genes were identified in the whole genome of Triplophysa dalaica in this study, including five copies of Na+-independent Cl-/HCO3- transporters, eight members of Na+-dependent HCO3- transporters, and two genes coding Na+-coupled borate transporters. The chromosomal location information, isoelectric points, and molecular weights of the 15 slc4 genes were analyzed. The results for gene structure, domain analysis, and phylogenetic relationships of this gene family showed that the slc4 genes (except for slc4a9, which is missing in teleosts) are significantly expanded in teleosts compared to higher vertebrates. This phenomenon suggests that the slc4 gene family played an important role in the transition from aquatic to terrestrial animals. RT-PCR results showed that different slc4 genes showed diversified expression patterns in the tissues of T. dalaica. For osmotic pressure regulating organs, slc4a1b, slc4a4b, slc4a7, and slc4a11a were highly expressed in gills. In the kidney, slc4a1a, slc4a3, and slc4a10b were highly expressed, suggesting that the slc4 genes play a specific role in the salinity adaptation of T. dalaica. Our study has deciphered the biological roles of the slc4 genes in maintaining ionic and acid-base homeostasis in teleost fishes and provides a foundation for future exploration of the highly differentiated gene family in Triplophysa. CONCLUSIONS The results are relevant for the breeding of alkali-tolerant varieties in saline-alkali areas for aquaculture. Our findings have important implications for the adaptation process of freshwater species to saline-alkali water.
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Affiliation(s)
- Chuanjiang Zhou
- grid.462338.80000 0004 0605 6769College of Life Sciences, Henan Normal University, Xinxiang, 453007 People’s Republic of China
| | - Bo Hu
- grid.462338.80000 0004 0605 6769College of Fisheries, Engineering Technology Research Center of Henan Province for Aquatic Animal Cultivation, Henan Normal University, Xinxiang, Henan 453007 People’s Republic of China
| | - Yongtao Tang
- grid.462338.80000 0004 0605 6769College of Fisheries, Engineering Technology Research Center of Henan Province for Aquatic Animal Cultivation, Henan Normal University, Xinxiang, Henan 453007 People’s Republic of China
| | - Xin Chen
- grid.462338.80000 0004 0605 6769College of Fisheries, Engineering Technology Research Center of Henan Province for Aquatic Animal Cultivation, Henan Normal University, Xinxiang, Henan 453007 People’s Republic of China
| | - Zhigang Ma
- grid.462338.80000 0004 0605 6769College of Fisheries, Engineering Technology Research Center of Henan Province for Aquatic Animal Cultivation, Henan Normal University, Xinxiang, Henan 453007 People’s Republic of China
| | - Qiqi Ding
- grid.462338.80000 0004 0605 6769College of Fisheries, Engineering Technology Research Center of Henan Province for Aquatic Animal Cultivation, Henan Normal University, Xinxiang, Henan 453007 People’s Republic of China
| | - Guoxing Nie
- grid.462338.80000 0004 0605 6769College of Fisheries, Engineering Technology Research Center of Henan Province for Aquatic Animal Cultivation, Henan Normal University, Xinxiang, Henan 453007 People’s Republic of China
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Delgado-Bermúdez A, Yeste M, Bonet S, Pinart E. A Review on the Role of Bicarbonate and Proton Transporters during Sperm Capacitation in Mammals. Int J Mol Sci 2022; 23:ijms23116333. [PMID: 35683013 PMCID: PMC9180951 DOI: 10.3390/ijms23116333] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Revised: 06/01/2022] [Accepted: 06/05/2022] [Indexed: 12/14/2022] Open
Abstract
Alkalinization of sperm cytosol is essential for plasma membrane hyperpolarization, hyperactivation of motility, and acrosomal exocytosis during sperm capacitation in mammals. The plasma membrane of sperm cells contains different ion channels implicated in the increase of internal pH (pHi) by favoring either bicarbonate entrance or proton efflux. Bicarbonate transporters belong to the solute carrier families 4 (SLC4) and 26 (SLC26) and are currently grouped into Na+/HCO3− transporters and Cl−/HCO3− exchangers. Na+/HCO3− transporters are reported to be essential for the initial and fast entrance of HCO3− that triggers sperm capacitation, whereas Cl−/HCO3− exchangers are responsible for the sustained HCO3− entrance which orchestrates the sequence of changes associated with sperm capacitation. Proton efflux is required for the fast alkalinization of capacitated sperm cells and the activation of pH-dependent proteins; according to the species, this transport can be mediated by Na+/H+ exchangers (NHE) belonging to the SLC9 family and/or voltage-gated proton channels (HVCN1). Herein, we discuss the involvement of each of these channels in sperm capacitation and the acrosome reaction.
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Affiliation(s)
- Ariadna Delgado-Bermúdez
- Biotechnology of Animal and Human Reproduction (TechnoSperm), Institute of Food and Agricultural Technology, University of Girona, ES-17003 Girona, Spain; (A.D.-B.); (M.Y.); (S.B.)
- Unit of Cell Biology, Department of Biology, Faculty of Sciences, University of Girona, ES-17003 Girona, Spain
| | - Marc Yeste
- Biotechnology of Animal and Human Reproduction (TechnoSperm), Institute of Food and Agricultural Technology, University of Girona, ES-17003 Girona, Spain; (A.D.-B.); (M.Y.); (S.B.)
- Unit of Cell Biology, Department of Biology, Faculty of Sciences, University of Girona, ES-17003 Girona, Spain
- Catalan Institution for Research and Advanced Studies (ICREA), ES-08010 Barcelona, Spain
| | - Sergi Bonet
- Biotechnology of Animal and Human Reproduction (TechnoSperm), Institute of Food and Agricultural Technology, University of Girona, ES-17003 Girona, Spain; (A.D.-B.); (M.Y.); (S.B.)
- Unit of Cell Biology, Department of Biology, Faculty of Sciences, University of Girona, ES-17003 Girona, Spain
| | - Elisabeth Pinart
- Biotechnology of Animal and Human Reproduction (TechnoSperm), Institute of Food and Agricultural Technology, University of Girona, ES-17003 Girona, Spain; (A.D.-B.); (M.Y.); (S.B.)
- Unit of Cell Biology, Department of Biology, Faculty of Sciences, University of Girona, ES-17003 Girona, Spain
- Correspondence: ; Tel.: +34-972-419-514
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10
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Remigante A, Spinelli S, Pusch M, Sarikas A, Morabito R, Marino A, Dossena S. Role of SLC4 and SLC26 solute carriers during oxidative stress. Acta Physiol (Oxf) 2022; 235:e13796. [PMID: 35143116 PMCID: PMC9542443 DOI: 10.1111/apha.13796] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Revised: 02/03/2022] [Accepted: 02/07/2022] [Indexed: 12/13/2022]
Abstract
Bicarbonate is one of the major anions in mammalian tissues and fluids, is utilized by various exchangers to transport other ions and organic substrates across cell membranes and plays a critical role in cell and systemic pH homoeostasis. Chloride/bicarbonate (Cl−/HCO3−) exchangers are abundantly expressed in erythrocytes and epithelial cells and, as a consequence, are particularly exposed to oxidants in the systemic circulation and at the interface with the external environment. Here, we review the physiological functions and pathophysiological alterations of Cl−/HCO3− exchangers belonging to the solute carriers SLC4 and SLC26 superfamilies in relation to oxidative stress. Particularly well studied is the impact of oxidative stress on the red blood cell SLC4A1/AE1 (Band 3 protein), of which the function seems to be directly affected by oxidative stress and possibly involves oxidation of the transporter itself or its interacting proteins, with detrimental consequences in oxidative stress‐related diseases including inflammation, metabolic dysfunctions and ageing. The effect of oxidative stress on SLC26 members was less extensively explored. Indirect evidence suggests that SLC26 transporters can be target as well as determinants of oxidative stress, especially when their expression is abolished or dysregulated.
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Affiliation(s)
- Alessia Remigante
- Biophysics Institute National Research Council Genova Italy
- Department of Chemical Biological, Pharmaceutical and Environmental Sciences University of Messina Messina Italy
| | - Sara Spinelli
- Department of Chemical Biological, Pharmaceutical and Environmental Sciences University of Messina Messina Italy
| | - Michael Pusch
- Biophysics Institute National Research Council Genova Italy
| | - Antonio Sarikas
- Institute of Pharmacology and Toxicology Paracelsus Medical University Salzburg Austria
| | - Rossana Morabito
- Department of Chemical Biological, Pharmaceutical and Environmental Sciences University of Messina Messina Italy
| | - Angela Marino
- Department of Chemical Biological, Pharmaceutical and Environmental Sciences University of Messina Messina Italy
| | - Silvia Dossena
- Institute of Pharmacology and Toxicology Paracelsus Medical University Salzburg Austria
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11
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SLC26A9 deficiency causes gastric intraepithelial neoplasia in mice and aggressive gastric cancer in humans. Cell Oncol (Dordr) 2022; 45:381-398. [PMID: 35426084 PMCID: PMC9187568 DOI: 10.1007/s13402-022-00672-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/29/2022] [Indexed: 11/23/2022] Open
Abstract
Background Solute carrier family 26 member (SLC26A9) is a Cl− uniporter with very high expression levels in the gastric mucosa. Here, we describe morphological and molecular alterations in gastric mucosa of slc26a9−/− mice and in selective parietal cell-deleted slc26a9fl/fl/Atp4b-Cre mice and correlate SLC26A9 expression levels with morphological and clinical parameters in a cohort of gastric cancer (GC) patients. Methods The expression patterns of genes related to transport and enzymatic function, proliferation, apoptosis, inflammation, barrier integrity, metaplasia and neoplasia development were studied by immunohistochemistry (IHC), quantitative RT-PCR, in situ hybridization and RNA microarray analysis. SLC26A9 expression and cellular/clinical phenotypes were studied in primary human GC tissues and GC cell lines. Results We found that both complete and parietal cell-selective Slc26a9 deletion in mice caused spontaneous development of gastric premalignant and malignant lesions. Dysregulated differentiation of gastric stem cells in an inflammatory environment, activated Wnt signaling, cellular hyperproliferation, apoptosis inhibition and metaplasia were observed. Analysis of human gastric precancerous and cancerous tissues revealed that SLC26A9 expression progressively decreased from atrophic gastritis to GC, and that downregulation of SLC26A9 was correlated with patient survival. Exogenous expression of SLC26A9 in GC cells induced upregulation of the Cl−/HCO3− exchanger AE2, G2/M cell cycle arrest and apoptosis and suppressed their proliferation, migration and invasion. Conclusions Our data indicate that SLC26A9 deletion in parietal cells is sufficient to trigger gastric metaplasia and the development of neoplastic lesions. In addition, we found that SLC26A9 expression decreases during human gastric carcinogenesis, and that exogenous SLC26A9 expression in GC cells reduces their malignant behavior. Graphical abstract ![]()
Supplementary Information The online version contains supplementary material available at 10.1007/s13402-022-00672-x.
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12
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Fang Y, Huang L, Wang X, Si X, Lenahan C, Shi H, Shao A, Tang J, Chen S, Zhang J, Zhang JH. A new perspective on cerebrospinal fluid dynamics after subarachnoid hemorrhage: From normal physiology to pathophysiological changes. J Cereb Blood Flow Metab 2022; 42:543-558. [PMID: 34806932 PMCID: PMC9051143 DOI: 10.1177/0271678x211045748] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Knowledge about the dynamic metabolism and function of cerebrospinal fluid (CSF) physiology has rapidly progressed in recent decades. It has traditionally been suggested that CSF is produced by the choroid plexus and drains to the arachnoid villi. However, recent findings have revealed that the brain parenchyma produces a large portion of CSF and drains through the perivascular glymphatic system and meningeal lymphatic vessels into the blood. The primary function of CSF is not limited to maintaining physiological CNS homeostasis but also participates in clearing waste products resulting from neurodegenerative diseases and acute brain injury. Aneurysmal subarachnoid hemorrhage (SAH), a disastrous subtype of acute brain injury, is associated with high mortality and morbidity. Post-SAH complications contribute to the poor outcomes associated with SAH. Recently, abnormal CSF flow was suggested to play an essential role in the post-SAH pathophysiological changes, such as increased intracerebral pressure, brain edema formation, hydrocephalus, and delayed blood clearance. An in-depth understanding of CSF dynamics in post-SAH events would shed light on potential development of SAH treatment options. This review summarizes and updates the latest physiological characteristics of CSF dynamics and discusses potential pathophysiological changes and therapeutic targets after SAH.
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Affiliation(s)
- Yuanjian Fang
- Department of Neurosurgery, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Lei Huang
- Department of Neurosurgery, Loma Linda University, Loma Linda, CA, USA.,Department of Physiology and Pharmacology, Loma Linda University, Loma Linda, CA, USA
| | - Xiaoyu Wang
- Department of Neurosurgery, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Xiaoli Si
- Department of Neurology, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Cameron Lenahan
- Department of Neurosurgery, Loma Linda University, Loma Linda, CA, USA.,Burrell College of Osteopathic Medicine, Las Cruces, NM, USA
| | - Hui Shi
- Department of Neurosurgery, Loma Linda University, Loma Linda, CA, USA.,Department of Neurosurgery, Yongchuan Hospital, Chongqing Medical University, Chongqing, China
| | - Anwen Shao
- Department of Neurosurgery, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Jiping Tang
- Department of Neurosurgery, Loma Linda University, Loma Linda, CA, USA.,Department of Physiology and Pharmacology, Loma Linda University, Loma Linda, CA, USA.,Department of Anesthesiology, Loma Linda University, Loma Linda, CA, USA
| | - Sheng Chen
- Department of Neurosurgery, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Jianmin Zhang
- Department of Neurosurgery, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - John H Zhang
- Department of Neurosurgery, Loma Linda University, Loma Linda, CA, USA.,Department of Physiology and Pharmacology, Loma Linda University, Loma Linda, CA, USA.,Department of Anesthesiology, Loma Linda University, Loma Linda, CA, USA
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13
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Kalli AC, Reithmeier RAF. Organization and Dynamics of the Red Blood Cell Band 3 Anion Exchanger SLC4A1: Insights From Molecular Dynamics Simulations. Front Physiol 2022; 13:817945. [PMID: 35283786 PMCID: PMC8914234 DOI: 10.3389/fphys.2022.817945] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Accepted: 01/27/2022] [Indexed: 01/16/2023] Open
Abstract
Molecular dynamics (MD) simulations have provided new insights into the organization and dynamics of the red blood cell Band 3 anion exchanger (AE1, SLC4A1). Band 3, like many solute carriers, works by an alternating access mode of transport where the protein rapidly (104/s) changes its conformation between outward and inward-facing states via a transient occluded anion-bound intermediate. While structural studies of membrane proteins usually reveal valuable structural information, these studies provide a static view often in the presence of detergents. Membrane transporters are embedded in a lipid bilayer and associated lipids play a role in their folding and function. In this review, we highlight MD simulations of Band 3 in realistic lipid bilayers that revealed specific lipid and protein interactions and were used to re-create a model of the Wright (Wr) blood group antigen complex of Band 3 and Glycophorin A. Current MD studies of Band 3 and related transporters are focused on describing the trajectory of substrate binding and translocation in real time. A structure of the intact Band 3 protein has yet to be achieved experimentally, but cryo-electron microscopy in combination with MD simulations holds promise to capture the conformational changes associated with anion transport in exquisite molecular detail.
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Affiliation(s)
- Antreas C. Kalli
- Leeds Institute of Cardiovascular and Metabolic Medicine and Astbury Center for Structural Molecular Biology, University of Leeds, Leeds, United Kingdom
| | - Reinhart A. F. Reithmeier
- Department of Biochemistry, University of Toronto, Toronto, ON, Canada
- *Correspondence: Reinhart A. F. Reithmeier,
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14
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Wu H, Liu S, Su P, Xie Z, Gui T, Zhao L, Liu Y, Chen L. Molecular insight into coordination sites for substrates and their coupling kinetics in Na
+
/HCO
3
−
cotransporter NBCe1. J Physiol 2022; 600:3083-3111. [DOI: 10.1113/jp282034] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Accepted: 02/03/2022] [Indexed: 11/08/2022] Open
Affiliation(s)
- Han Wu
- Key Laboratory of Molecular Biophysics of Ministry of Education School of Life Science & Technology Huazhong University of Science & Technology Wuhan 430074 China
| | - Shiyong Liu
- School of Physics Huazhong University of Science and Technology Wuhan 430074 China
| | - Pan Su
- Key Laboratory of Molecular Biophysics of Ministry of Education School of Life Science & Technology Huazhong University of Science & Technology Wuhan 430074 China
| | - Zhang‐Dong Xie
- Key Laboratory of Molecular Biophysics of Ministry of Education School of Life Science & Technology Huazhong University of Science & Technology Wuhan 430074 China
| | - Tian‐Xiang Gui
- Key Laboratory of Molecular Biophysics of Ministry of Education School of Life Science & Technology Huazhong University of Science & Technology Wuhan 430074 China
| | - Lei Zhao
- Department of Obstetrics Maternal and Child Health Hospital of Hubei Province Wuhan 430070 China
| | - Ying Liu
- Key Laboratory of Molecular Biophysics of Ministry of Education School of Life Science & Technology Huazhong University of Science & Technology Wuhan 430074 China
| | - Li‐Ming Chen
- Key Laboratory of Molecular Biophysics of Ministry of Education School of Life Science & Technology Huazhong University of Science & Technology Wuhan 430074 China
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15
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Whittamore JM, Hatch M. Oxalate Flux Across the Intestine: Contributions from Membrane Transporters. Compr Physiol 2021; 12:2835-2875. [PMID: 34964122 DOI: 10.1002/cphy.c210013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Epithelial oxalate transport is fundamental to the role occupied by the gastrointestinal (GI) tract in oxalate homeostasis. The absorption of dietary oxalate, together with its secretion into the intestine, and degradation by the gut microbiota, can all influence the excretion of this nonfunctional terminal metabolite in the urine. Knowledge of the transport mechanisms is relevant to understanding the pathophysiology of hyperoxaluria, a risk factor in kidney stone formation, for which the intestine also offers a potential means of treatment. The following discussion presents an expansive review of intestinal oxalate transport. We begin with an overview of the fate of oxalate, focusing on the sources, rates, and locations of absorption and secretion along the GI tract. We then consider the mechanisms and pathways of transport across the epithelial barrier, discussing the transcellular, and paracellular components. There is an emphasis on the membrane-bound anion transporters, in particular, those belonging to the large multifunctional Slc26 gene family, many of which are expressed throughout the GI tract, and we summarize what is currently known about their participation in oxalate transport. In the final section, we examine the physiological stimuli proposed to be involved in regulating some of these pathways, encompassing intestinal adaptations in response to chronic kidney disease, metabolic acid-base disorders, obesity, and following gastric bypass surgery. There is also an update on research into the probiotic, Oxalobacter formigenes, and the basis of its unique interaction with the gut epithelium. © 2021 American Physiological Society. Compr Physiol 11:1-41, 2021.
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Affiliation(s)
- Jonathan M Whittamore
- Department of Pathology, Immunology and Laboratory Medicine, College of Medicine, University of Florida, Gainesville, Florida, USA
| | - Marguerite Hatch
- Department of Pathology, Immunology and Laboratory Medicine, College of Medicine, University of Florida, Gainesville, Florida, USA
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16
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Ponomareva D, Petukhova E, Bregestovski P. Simultaneous Monitoring of pH and Chloride (Cl -) in Brain Slices of Transgenic Mice. Int J Mol Sci 2021; 22:13601. [PMID: 34948398 PMCID: PMC8708776 DOI: 10.3390/ijms222413601] [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: 11/28/2021] [Revised: 12/13/2021] [Accepted: 12/14/2021] [Indexed: 11/16/2022] Open
Abstract
Optosensorics is the direction of research possessing the possibility of non-invasive monitoring of the concentration of intracellular ions or activity of intracellular components using specific biosensors. In recent years, genetically encoded proteins have been used as effective optosensory means. These probes possess fluorophore groups capable of changing fluorescence when interacting with certain ions or molecules. For monitoring of intracellular concentrations of chloride ([Cl-]i) and hydrogen ([H+] i) the construct, called ClopHensor, which consists of a H+- and Cl--sensitive variant of the enhanced green fluorescent protein (E2GFP) fused with a monomeric red fluorescent protein (mDsRed) has been proposed. We recently developed a line of transgenic mice expressing ClopHensor in neurons and obtained the map of its expression in different areas of the brain. The purpose of this study was to examine the effectiveness of transgenic mice expressing ClopHensor for estimation of [H+]i and [Cl-]i concentrations in neurons of brain slices. We performed simultaneous monitoring of [H+]i and [Cl-]i under different experimental conditions including changing of external concentrations of ions (Ca2+, Cl-, K+, Na+) and synaptic stimulation of Shaffer's collaterals of hippocampal slices. The results obtained illuminate different pathways of regulation of Cl- and pH equilibrium in neurons and demonstrate that transgenic mice expressing ClopHensor represent a reliable tool for non-invasive simultaneous monitoring of intracellular Cl- and pH.
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Affiliation(s)
- Daria Ponomareva
- Institut de Neurosciences des Systèmes, Aix-Marseille University, INSERM, INS, 13005 Marseille, France;
- Institute of Neurosciences, Kazan State Medical University, 420111 Kazan, Russia;
- Department of Normal Physiology, Kazan State Medical University, 420111 Kazan, Russia
| | - Elena Petukhova
- Institute of Neurosciences, Kazan State Medical University, 420111 Kazan, Russia;
- Department of Normal Physiology, Kazan State Medical University, 420111 Kazan, Russia
| | - Piotr Bregestovski
- Institut de Neurosciences des Systèmes, Aix-Marseille University, INSERM, INS, 13005 Marseille, France;
- Institute of Neurosciences, Kazan State Medical University, 420111 Kazan, Russia;
- Department of Normal Physiology, Kazan State Medical University, 420111 Kazan, Russia
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17
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Wang W, Tsirulnikov K, Zhekova HR, Kayık G, Khan HM, Azimov R, Abuladze N, Kao L, Newman D, Noskov SY, Zhou ZH, Pushkin A, Kurtz I. Cryo-EM structure of the sodium-driven chloride/bicarbonate exchanger NDCBE. Nat Commun 2021; 12:5690. [PMID: 34584093 PMCID: PMC8478935 DOI: 10.1038/s41467-021-25998-2] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Accepted: 09/08/2021] [Indexed: 02/08/2023] Open
Abstract
SLC4 transporters play significant roles in pH regulation and cellular sodium transport. The previously solved structures of the outward facing (OF) conformation for AE1 (SLC4A1) and NBCe1 (SLC4A4) transporters revealed an identical overall fold despite their different transport modes (chloride/bicarbonate exchange versus sodium-carbonate cotransport). However, the exact mechanism determining the different transport modes in the SLC4 family remains unknown. In this work, we report the cryo-EM 3.4 Å structure of the OF conformation of NDCBE (SLC4A8), which shares transport properties with both AE1 and NBCe1 by mediating the electroneutral exchange of sodium-carbonate with chloride. This structure features a fully resolved extracellular loop 3 and well-defined densities corresponding to sodium and carbonate ions in the tentative substrate binding pocket. Further, we combine computational modeling with functional studies to unravel the molecular determinants involved in NDCBE and SLC4 transport.
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Affiliation(s)
- Weiguang Wang
- grid.19006.3e0000 0000 9632 6718Department of Medicine, Division of Nephrology, David Geffen School of Medicine, University of California, Los Angeles, CA USA ,grid.509979.b0000 0004 7666 6191Electron Imaging Center for Nanomachines, California NanoSystems Institute, University of California, Los Angeles, CA USA
| | - Kirill Tsirulnikov
- grid.19006.3e0000 0000 9632 6718Department of Medicine, Division of Nephrology, David Geffen School of Medicine, University of California, Los Angeles, CA USA
| | - Hristina R. Zhekova
- grid.22072.350000 0004 1936 7697Centre for Molecular Simulation, Department of Biological Sciences, University of Calgary, Calgary, Canada
| | - Gülru Kayık
- grid.22072.350000 0004 1936 7697Centre for Molecular Simulation, Department of Biological Sciences, University of Calgary, Calgary, Canada
| | - Hanif Muhammad Khan
- grid.22072.350000 0004 1936 7697Centre for Molecular Simulation, Department of Biological Sciences, University of Calgary, Calgary, Canada
| | - Rustam Azimov
- grid.19006.3e0000 0000 9632 6718Department of Medicine, Division of Nephrology, David Geffen School of Medicine, University of California, Los Angeles, CA USA
| | - Natalia Abuladze
- grid.19006.3e0000 0000 9632 6718Department of Medicine, Division of Nephrology, David Geffen School of Medicine, University of California, Los Angeles, CA USA
| | - Liyo Kao
- grid.19006.3e0000 0000 9632 6718Department of Medicine, Division of Nephrology, David Geffen School of Medicine, University of California, Los Angeles, CA USA
| | - Debbie Newman
- grid.19006.3e0000 0000 9632 6718Department of Medicine, Division of Nephrology, David Geffen School of Medicine, University of California, Los Angeles, CA USA
| | - Sergei Yu. Noskov
- grid.22072.350000 0004 1936 7697Centre for Molecular Simulation, Department of Biological Sciences, University of Calgary, Calgary, Canada
| | - Z. Hong Zhou
- grid.509979.b0000 0004 7666 6191Electron Imaging Center for Nanomachines, California NanoSystems Institute, University of California, Los Angeles, CA USA ,grid.19006.3e0000 0000 9632 6718Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, CA USA
| | - Alexander Pushkin
- grid.19006.3e0000 0000 9632 6718Department of Medicine, Division of Nephrology, David Geffen School of Medicine, University of California, Los Angeles, CA USA
| | - Ira Kurtz
- grid.19006.3e0000 0000 9632 6718Department of Medicine, Division of Nephrology, David Geffen School of Medicine, University of California, Los Angeles, CA USA ,grid.19006.3e0000 0000 9632 6718Brain Research Institute, University of California, Los Angeles, CA USA
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18
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Li H, Guan Y, Han C, Zhang Y, Liu Q, Wei W, Ma Y. The pathogenesis, models and therapeutic advances of primary biliary cholangitis. Biomed Pharmacother 2021; 140:111754. [PMID: 34044277 DOI: 10.1016/j.biopha.2021.111754] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 05/17/2021] [Accepted: 05/19/2021] [Indexed: 12/30/2022] Open
Abstract
Primary biliary cholangitis (PBC) is an autoimmune disease characterized by the destruction of intrahepatic small bile ducts and the presence of antimitochondrial antibody (AMA), eventually progresses to liver fibrosis and cirrhosis. Genetic predisposition and environmental factors are involved in the occurrence of PBC, and the epitopes exposure and the imbalance of autoimmune tolerance are the last straw. The apoptosis of biliary epithelial cell (BEC) leads to the release of autoantigen epitopes, which activate the immune system, and the disorder of innate and adaptive immunity eventually leads to the start of disease. Animal models have unique advantages in investigating the pathogenesis and drug exploitation of PBC. Multiple models have been reported, and spontaneous model and induced model have been widely used in relevant research of PBC in recent years. Currently, the only drugs licensed for PBC are ursodesoxycholic acid (UDCA) and obeticholic acid (OCA). In the last few years, as the learned more about the pathogenesis of PBC, more and more targets have been discovered, and multiple targeted drugs are being in developed. In this review, the pathogenesis, murine models and treatment strategies of PBC were summarized, and the current research status was discussed to provide insights for the further study of PBC.
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Affiliation(s)
- Hao Li
- Institute of Clinical Pharmacology, Anhui Medical University, Key Laboratory of Anti-inflammatory and Immune Medicine, Ministry of Education, Anhui Collaborative Innovation Center of Anti-inflammatory and Immune Medicine, Hefei, China
| | - Yanling Guan
- Institute of Clinical Pharmacology, Anhui Medical University, Key Laboratory of Anti-inflammatory and Immune Medicine, Ministry of Education, Anhui Collaborative Innovation Center of Anti-inflammatory and Immune Medicine, Hefei, China
| | - Chenchen Han
- Institute of Clinical Pharmacology, Anhui Medical University, Key Laboratory of Anti-inflammatory and Immune Medicine, Ministry of Education, Anhui Collaborative Innovation Center of Anti-inflammatory and Immune Medicine, Hefei, China
| | - Yu Zhang
- Institute of Clinical Pharmacology, Anhui Medical University, Key Laboratory of Anti-inflammatory and Immune Medicine, Ministry of Education, Anhui Collaborative Innovation Center of Anti-inflammatory and Immune Medicine, Hefei, China
| | - Qian Liu
- Institute of Clinical Pharmacology, Anhui Medical University, Key Laboratory of Anti-inflammatory and Immune Medicine, Ministry of Education, Anhui Collaborative Innovation Center of Anti-inflammatory and Immune Medicine, Hefei, China
| | - Wei Wei
- Institute of Clinical Pharmacology, Anhui Medical University, Key Laboratory of Anti-inflammatory and Immune Medicine, Ministry of Education, Anhui Collaborative Innovation Center of Anti-inflammatory and Immune Medicine, Hefei, China.
| | - Yang Ma
- Institute of Clinical Pharmacology, Anhui Medical University, Key Laboratory of Anti-inflammatory and Immune Medicine, Ministry of Education, Anhui Collaborative Innovation Center of Anti-inflammatory and Immune Medicine, Hefei, China.
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19
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Wu H, Chen C, Ziani S, Nelson LJ, Ávila MA, Nevzorova YA, Cubero FJ. Fibrotic Events in the Progression of Cholestatic Liver Disease. Cells 2021; 10:cells10051107. [PMID: 34062960 PMCID: PMC8147992 DOI: 10.3390/cells10051107] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Revised: 04/28/2021] [Accepted: 04/30/2021] [Indexed: 02/07/2023] Open
Abstract
Cholestatic liver diseases including primary biliary cholangitis (PBC) and primary sclerosing cholangitis (PSC) are associated with active hepatic fibrogenesis, which can ultimately lead to the development of cirrhosis. However, the exact relationship between the development of liver fibrosis and the progression of cholestatic liver disease remains elusive. Periductular fibroblasts located around the bile ducts seem biologically different from hepatic stellate cells (HSCs). The fibrotic events in these clinical conditions appear to be related to complex crosstalk between immune/inflammatory mechanisms, cytokine signalling, and perturbed homeostasis between cholangiocytes and mesenchymal cells. Several animal models including bile duct ligation (BDL) and the Mdr2-knockout mice have improved our understanding of mechanisms underlying chronic cholestasis. In the present review, we aim to elucidate the mechanisms of fibrosis in order to help to identify potential diagnostic and therapeutic targets.
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Affiliation(s)
- Hanghang Wu
- Department of Immunology, Ophthalmology & ENT, Complutense University School of Medicine, 28040 Madrid, Spain; (H.W.); (C.C.); (S.Z.); (Y.A.N.)
| | - Chaobo Chen
- Department of Immunology, Ophthalmology & ENT, Complutense University School of Medicine, 28040 Madrid, Spain; (H.W.); (C.C.); (S.Z.); (Y.A.N.)
- Health Research Institute Gregorio Marañón (IiSGM), 28007 Madrid, Spain
- Department of General Surgery, Wuxi Xishan People’s Hospital, Wuxi 214000, China
| | - Siham Ziani
- Department of Immunology, Ophthalmology & ENT, Complutense University School of Medicine, 28040 Madrid, Spain; (H.W.); (C.C.); (S.Z.); (Y.A.N.)
| | - Leonard J. Nelson
- Institute for Bioengineering (IBioE), School of Engineering, Faraday Building, The University of Edinburgh, Edinburgh EH9 3 JL, Scotland, UK;
- Institute of Biological Chemistry, Biophysics and Bioengineering (IB3), School of Engineering and Physical Sciences (EPS), Heriot-Watt University, Edinburgh EH14 4AS, Scotland, UK
| | - Matías A. Ávila
- Hepatology Program, Center for Applied Medical Research (CIMA), University of Navarra, 31008 Pamplona, Spain;
- Centro de Investigacion Biomedica en Red, Enfermedades Hepáticas y Digestivas (CIBERehd), 28029 Madrid, Spain
- Instituto de Investigaciones Sanitarias de Navarra IdiSNA, 31008 Pamplona, Spain
| | - Yulia A. Nevzorova
- Department of Immunology, Ophthalmology & ENT, Complutense University School of Medicine, 28040 Madrid, Spain; (H.W.); (C.C.); (S.Z.); (Y.A.N.)
- Health Research Institute Gregorio Marañón (IiSGM), 28007 Madrid, Spain
- Centro de Investigacion Biomedica en Red, Enfermedades Hepáticas y Digestivas (CIBERehd), 28029 Madrid, Spain
- Department of Internal Medicine III, University Hospital RWTH Aachen, 52074 Aachen, Germany
| | - Francisco Javier Cubero
- Department of Immunology, Ophthalmology & ENT, Complutense University School of Medicine, 28040 Madrid, Spain; (H.W.); (C.C.); (S.Z.); (Y.A.N.)
- Health Research Institute Gregorio Marañón (IiSGM), 28007 Madrid, Spain
- Centro de Investigacion Biomedica en Red, Enfermedades Hepáticas y Digestivas (CIBERehd), 28029 Madrid, Spain
- Correspondence: ; Tel.: +34-91-394-1385; Fax: +34-91-394-1641
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20
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Zajac M, Dreano E, Edwards A, Planelles G, Sermet-Gaudelus I. Airway Surface Liquid pH Regulation in Airway Epithelium Current Understandings and Gaps in Knowledge. Int J Mol Sci 2021; 22:3384. [PMID: 33806154 PMCID: PMC8037888 DOI: 10.3390/ijms22073384] [Citation(s) in RCA: 46] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 03/08/2021] [Accepted: 03/08/2021] [Indexed: 12/22/2022] Open
Abstract
Knowledge on the mechanisms of acid and base secretion in airways has progressed recently. The aim of this review is to summarize the known mechanisms of airway surface liquid (ASL) pH regulation and their implication in lung diseases. Normal ASL is slightly acidic relative to the interstitium, and defects in ASL pH regulation are associated with various respiratory diseases, such as cystic fibrosis. Basolateral bicarbonate (HCO3-) entry occurs via the electrogenic, coupled transport of sodium (Na+) and HCO3-, and, together with carbonic anhydrase enzymatic activity, provides HCO3- for apical secretion. The latter mainly involves CFTR, the apical chloride/bicarbonate exchanger pendrin and paracellular transport. Proton (H+) secretion into ASL is crucial to maintain its relative acidity compared to the blood. This is enabled by H+ apical secretion, mainly involving H+/K+ ATPase and vacuolar H+-ATPase that carry H+ against the electrochemical potential gradient. Paracellular HCO3- transport, the direction of which depends on the ASL pH value, acts as an ASL protective buffering mechanism. How the transepithelial transport of H+ and HCO3- is coordinated to tightly regulate ASL pH remains poorly understood, and should be the focus of new studies.
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Affiliation(s)
- Miroslaw Zajac
- Department of Physics and Biophysics, Institute of Biology, Warsaw University of Life Sciences, 02-776 Warsaw, Poland;
| | - Elise Dreano
- Institut Necker Enfants Malades, INSERM U1151, 75015 Paris, France;
- Centre de Recherche des Cordeliers, Sorbonne Université, INSERM, Université de Paris, 75006 Paris, France;
| | - Aurelie Edwards
- Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA;
| | - Gabrielle Planelles
- Centre de Recherche des Cordeliers, Sorbonne Université, INSERM, Université de Paris, 75006 Paris, France;
- Laboratoire de Physiologie rénale et Tubulopathies, CNRS ERL 8228, 75006 Paris, France
| | - Isabelle Sermet-Gaudelus
- Institut Necker Enfants Malades, INSERM U1151, 75015 Paris, France;
- Centre de Recherche des Cordeliers, Sorbonne Université, INSERM, Université de Paris, 75006 Paris, France;
- Centre de Référence Maladies Rares, Mucoviscidose et Maladies de CFTR, Hôpital Necker Enfants Malades, 75015 Paris, France
- Clinical Trial Network, European Cystic Fibrosis Society, BT2 Belfast, Ireland
- European Respiratory Network Lung, 75006 Paris, France
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21
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Schoels M, Zhuang M, Fahrner A, Küchlin S, Sagar, Franz H, Schmitt A, Walz G, Yakulov TA. Single-cell mRNA profiling reveals changes in solute carrier expression and suggests a metabolic switch during zebrafish pronephros development. Am J Physiol Renal Physiol 2021; 320:F826-F837. [PMID: 33749326 DOI: 10.1152/ajprenal.00610.2020] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Developing organisms need to adapt to environmental variations as well as to rapid changes in substrate availability and energy demands imposed by fast-growing tissues and organs. Little is known about the adjustments that kidneys undergo in response to these challenges. We performed single-cell RNA sequencing of zebrafish pronephric duct cells to understand how the developing kidney responds to changes in filtered substrates and intrinsic energy requirements. We found high levels of glucose transporters early in development and increased expression of monocarboxylate transporters at later times. This indicates that the zebrafish embryonic kidney displays a high glucose transporting capacity during early development, which is replaced by the ability to absorb monocarboxylates and amino acids at later stages. This change in transport capacity was accompanied by the upregulation of mitochondrial carriers, indicating a switch to increased oxidative phosphorylation to meet the increasing energy demand of a developing kidney.NEW & NOTEWORTHY The zebrafish embryonic kidney has high levels of glucose transporters during early development, which are replaced by monocarboxylate and amino acid transporters later on. Inhibition of Na+-glucose cotransporter-dependent glucose transport by sotagliflozin also increased slc2a1a expression, supporting the idea that the glucose transport capacity is dynamically adjusted during zebrafish pronephros development. Concurrent upregulation of mitochondrial SCL25 transporters at later stages supports the idea that the pronephros adjusts to changing substrate supplies and/or energy demands during embryonic development.
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Affiliation(s)
- Maximilian Schoels
- Renal Division, Department of Medicine, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, Germany
| | - Mingyue Zhuang
- Renal Division, Department of Medicine, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, Germany
| | - Andreas Fahrner
- Renal Division, Department of Medicine, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, Germany
| | - Sebastian Küchlin
- Renal Division, Department of Medicine, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, Germany.,Department of Ophthamology, Faculty of Medicine, University Freiburg Medical Center, University of Freiburg, Freiburg, Germany
| | - Sagar
- Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany
| | - Henriette Franz
- Department of Biomedicine, University of Basel, Basel, Switzerland
| | - Annette Schmitt
- Renal Division, Department of Medicine, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, Germany
| | - Gerd Walz
- Renal Division, Department of Medicine, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, Germany.,Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Freiburg, Germany
| | - Toma A Yakulov
- Renal Division, Department of Medicine, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, Germany
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22
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Becker HM, Deitmer JW. Proton Transport in Cancer Cells: The Role of Carbonic Anhydrases. Int J Mol Sci 2021; 22:ijms22063171. [PMID: 33804674 PMCID: PMC8003680 DOI: 10.3390/ijms22063171] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Revised: 03/16/2021] [Accepted: 03/17/2021] [Indexed: 02/06/2023] Open
Abstract
Intra- and extracellular pH regulation is a pivotal function of all cells and tissues. Net outward transport of H+ is a prerequisite for normal physiological function, since a number of intracellular processes, such as metabolism and energy supply, produce acid. In tumor tissues, distorted pH regulation results in extracellular acidification and the formation of a hostile environment in which cancer cells can outcompete healthy local host cells. Cancer cells employ a variety of H+/HCO3−-coupled transporters in combination with intra- and extracellular carbonic anhydrase (CA) isoforms, to alter intra- and extracellular pH to values that promote tumor progression. Many of the transporters could closely associate to CAs, to form a protein complex coined “transport metabolon”. While transport metabolons built with HCO3−-coupled transporters require CA catalytic activity, transport metabolons with monocarboxylate transporters (MCTs) operate independently from CA catalytic function. In this article, we assess some of the processes and functions of CAs for tumor pH regulation and discuss the role of intra- and extracellular pH regulation for cancer pathogenesis and therapeutic intervention.
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Affiliation(s)
- Holger M. Becker
- Zoology and Animal Physiology, Institute of Zoology, TU Dresden, D-01217 Dresden, Germany
- Correspondence:
| | - Joachim W. Deitmer
- Department of Biology, University of Kaiserslautern, D-67653 Kaiserslautern, Germany;
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23
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Tscherner AK, Macaulay AD, Ortman CS, Baltz JM. Initiation of cell volume regulation and unique cell volume regulatory mechanisms in mammalian oocytes and embryos. J Cell Physiol 2021; 236:7117-7133. [PMID: 33634482 DOI: 10.1002/jcp.30352] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 02/09/2021] [Accepted: 02/17/2021] [Indexed: 11/07/2022]
Abstract
The period beginning with the signal for ovulation, when a fully-grown oocyte progresses through meiosis to become a mature egg that is fertilized and develops as a preimplantation embryo, is crucial for healthy development. The early preimplantation embryo is unusually sensitive to cell volume perturbations, with even moderate decreases in volume or dysregulation of volume-regulatory mechanisms resulting in developmental arrest. To prevent this, early embryos possess mechanisms of cell volume control that are apparently unique to them. These rely on the accumulation of glycine and betaine (N, N, N-trimethylglycine) as organic osmolytes-compounds that can provide intracellular osmotic support without the deleterious effects of inorganic ions. Preimplantation embryos also have the same mechanisms as somatic cells that mediate rapid responses to deviations in cell volume, which rely on inorganic ion transport. Both the unique, embryo-specific mechanisms that use glycine and betaine and the inorganic ion-dependent mechanisms undergo major changes during meiotic maturation and preimplantation development. The most profound changes occur immediately after ovulation is triggered. Before this, oocytes cannot regulate their volume, since they are strongly attached to their rigid extracellular matrix shell, the zona pellucida. After ovulation is triggered, the oocyte detaches from the zona pellucida and first becomes capable of independent volume regulation. A complex set of developmental changes in each cell volume-regulatory mechanism continues through egg maturation and preimplantation development. The unique cell volume-regulatory mechanisms in eggs and preimplantation embryos and the developmental changes they undergo appear critical for normal healthy embryo development.
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Affiliation(s)
- Allison K Tscherner
- Ottawa Hospital Research Institute, Ottawa, Ontario, Canada
- Department of Obstetrics and Gynecology, University of Ottawa, Ottawa, Ontario, Canada
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario, Canada
| | - Angus D Macaulay
- Ottawa Hospital Research Institute, Ottawa, Ontario, Canada
- Department of Obstetrics and Gynecology, University of Ottawa, Ottawa, Ontario, Canada
| | - Chyna S Ortman
- Ottawa Hospital Research Institute, Ottawa, Ontario, Canada
- Department of Obstetrics and Gynecology, University of Ottawa, Ottawa, Ontario, Canada
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario, Canada
| | - Jay M Baltz
- Ottawa Hospital Research Institute, Ottawa, Ontario, Canada
- Department of Obstetrics and Gynecology, University of Ottawa, Ottawa, Ontario, Canada
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario, Canada
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24
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Remigante A, Morabito R, Marino A. Band 3 protein function and oxidative stress in erythrocytes. J Cell Physiol 2021; 236:6225-6234. [PMID: 33559172 DOI: 10.1002/jcp.30322] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2020] [Revised: 01/24/2021] [Accepted: 01/28/2021] [Indexed: 12/17/2022]
Abstract
Band 3 protein (B3p), anion transporter, allows the HCO3 - /Cl- exchange across plasma membrane and plays an important role for erythrocytes homeostasis. In addition, B3p is linked to proteins cytoskeleton, thus contributing to cell shape and deformability, essential to erythrocytes adjustment within narrowest capillaries. Taking into account that erythrocytes are a suitable cell model to investigate the response of the oxidative stress effects, B3p functions, and specifically anion exchange capability, determining the rate constant for SO4 2- uptake, has been considered. As, in the latter years, rising attention has been addressed to membrane transport system, and particularly to this protein, the present mini-review has been conceived to report the most recent knowledge about B3p, with specific regard to its functions in oxidative stress conditions, including oxidative stress-related diseases.
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Affiliation(s)
- Alessia Remigante
- Institute of Biophysics, National Research Council, Genoa, Italy.,Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, Messina, Italy
| | - Rossana Morabito
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, Messina, Italy
| | - Angela Marino
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, Messina, Italy
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25
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The electrogenic sodium bicarbonate cotransporter and its roles in the myocardial ischemia-reperfusion induced cardiac diseases. Life Sci 2021; 270:119153. [PMID: 33539911 DOI: 10.1016/j.lfs.2021.119153] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Revised: 01/06/2021] [Accepted: 01/22/2021] [Indexed: 12/19/2022]
Abstract
Cardiac tissue ischemia/hypoxia increases glycolysis and lactic acid accumulation in cardiomyocytes, leading to intracellular metabolic acidosis. Sodium bicarbonate cotransporters (NBCs) play a vital role in modulating intracellular pH and maintaining sodium ion concentrations in cardiomyocytes. Cardiomyocytes mainly express electrogenic sodium bicarbonate cotransporter (NBCe1), which has been demonstrated to participate in myocardial ischemia/reperfusion (I/R) injury. This review outlines the structural and functional properties of NBCe1, summarizes the signaling pathways and factors that may regulate the activity of NBCe1, and reviews the roles of NBCe1 in the pathogenesis of I/R-induced cardiac diseases. Further studies revealing the regulatory mechanisms of NBCe1 activity should provide novel therapeutic targets for preventing I/R-induced cardiac diseases.
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26
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Slc4 Gene Family in Spotted Sea Bass (Lateolabrax maculatus): Structure, Evolution, and Expression Profiling in Response to Alkalinity Stress and Salinity Changes. Genes (Basel) 2020; 11:genes11111271. [PMID: 33126655 PMCID: PMC7692064 DOI: 10.3390/genes11111271] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 10/23/2020] [Accepted: 10/26/2020] [Indexed: 12/11/2022] Open
Abstract
The solute carrier 4 (SLC4) family is a class of cell membranes transporters involved in base transport that plays crucial roles in diverse physiological processes. In our study, 15 slc4 genes were identified and annotated in spotted sea bass, including five members of Cl−/HCO3− exchangers, eight genes coding Na+-dependent HCO3− transporters, and two copies of Na+-coupled borate transporters. The gene sequence and structure, chromosomal and syntenic arrangement, phylogenetic and evolution profiles were analyzed. Results showed that the slc4 gene in teleosts obviously expanded compared with higher vertebrates, arising from teleost-specific whole genome duplication event. Most gene sites of slc4 in spotted sea bass were under strong purifying selection during evolution, while positive selection sites were only detected in slc4a1b, slc4a8, and slc4a10b. Additionally, qRT-PCR results showed that different slc4 genes exhibited distinct branchial expression patterns after alkalinity and salinity stresses, of which the strongly responsive members may play essential roles during these physiological processes. Our study provides the systemic overview of the slc4 gene family in spotted sea bass and enables a better understanding for the evolution of this family and further deciphering the biological roles in maintaining ion and acid–base homeostasis in teleosts.
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27
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Human Sperm Capacitation Involves the Regulation of the Tyr-Phosphorylation Level of the Anion Exchanger 1 (AE1). Int J Mol Sci 2020; 21:ijms21114063. [PMID: 32517126 PMCID: PMC7311965 DOI: 10.3390/ijms21114063] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Revised: 06/02/2020] [Accepted: 06/03/2020] [Indexed: 12/22/2022] Open
Abstract
Bicarbonate uptake is one of the early steps of capacitation, but the identification of proteins regulating anion fluxes remains elusive. The aim of this study is to investigate the role of sperm solute carrier 4 (SLC4) A1 (spAE1) in the capacitation process. The expression, location, and tyrosine-phosphorylation (Tyr-P) level of spAE1 were assessed. Thereby, it was found that 4,4′-Diisothiocyano-2,2′-stilbenedisulfonic acid (DIDS), an SLC4 family channel blocker, inhibited capacitation in a dose-dependent manner by decreasing acrosome reaction (ARC% 24.5 ± 3.3 vs. 64.9 ± 4.3, p < 0.05) and increasing the percentage of not viable cells (NVC%), comparable to the inhibition by I-172, a cystic fibrosis transmembrane conductance regulator (CFTR) blocker (AR% 30.5 ± 4.4 and NVC% 18.6 ± 2.2). When used in combination, a synergistic inhibitory effect was observed with a remarkable increase of the percentage of NVC (45.3 ± 4.1, p < 0.001). spAE1 was identified in sperm membrane as a substrate for Tyr-protein kinases Lyn and Syk, which were identified as both soluble and membrane-bound pools. spAE1-Tyr-P level increased in the apical region of sperm under capacitating conditions and was negatively affected by I-172 or DIDS, and, to a far greater extent, by a combination of both. In conclusion, we demonstrated that spAE1 is expressed in sperm membranes and it is phosphorylated by Syk, but above all by Lyn on Tyr359, which are involved in sperm viability and capacitation.
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28
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Bonnet U, Wiemann M. Topiramate Decelerates Bicarbonate-Driven Acid-Elimination of Human Neocortical Neurons: Strategic Significance for its Antiepileptic, Antimigraine and Neuroprotective Properties. CNS & NEUROLOGICAL DISORDERS-DRUG TARGETS 2020; 19:264-275. [PMID: 32496992 DOI: 10.2174/1871527319666200604173208] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2019] [Revised: 04/08/2020] [Accepted: 04/09/2020] [Indexed: 12/27/2022]
Abstract
BACKGROUND Mammalian central neurons regulate their intracellular pH (pHi) strongly and even slight pHi-fluctuations can influence inter-/intracellular signaling, synaptic plasticity and excitability. OBJECTIVE For the first time, we investigated topiramate´s (TPM) influence on pHi-behavior of human central neurons representing a promising target for anticonvulsants and antimigraine drugs. METHODS In slice-preparations of tissue resected from the middle temporal gyrus of five adults with intractable temporal lobe epilepsy, BCECF-AM-loaded neocortical pyramidal-cells were investigated by fluorometry. The pHi-regulation was estimated by using the recovery-slope from intracellular acidification after an Ammonium-Prepulse (APP). RESULTS Among 17 pyramidal neurons exposed to 50 μM TPM, seven (41.24%) responded with an altered resting-pHi (7.02±0.12), i.e., acidification of 0.01-0.03 pH-units. The more alkaline the neurons, the greater the TPM-related acidifications (r=0.7, p=0.001, n=17). The recovery from APPacidification was significantly slowed under TPM (p<0.001, n=5). Further experiments using nominal bicarbonate-free (n=2) and chloride-free (n=2) conditions pointed to a modulation of the HCO3 -- driven pHi-regulation by TPM, favoring a stimulation of the passive Cl-/HCO3 --antiporter (CBT) - an acid-loader predominantly in more alkaline neurons. CONCLUSION TPM modulated the bicarbonate-driven pHi-regulation, just as previously described in adult guinea-pig hippocampal neurons. We discussed the significance of the resulting subtle acidifications for beneficial antiepileptic, antimigraine and neuroprotective effects as well as for unwanted cognitive deficits.
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Affiliation(s)
- Udo Bonnet
- Department of Psychiatry, Psychotherapy, and Psychosomatic Medicine, Evangelisches Krankenhaus Castrop-Rauxel, Academic Teaching Hospital of the University Duisburg-Essen, Castrop-Rauxel, Germany.,Department of Psychiatry and Psychotherapy, Faculty of Medicine, LVR-Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Martin Wiemann
- Institute of Physiology, University of Duisburg-Essen, Essen, Germany.,IBE R&D gGmbH, Institute for Lung Health, D-48149 Munster, Germany
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29
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Drobin K, Marczyk M, Halle M, Danielsson D, Papiez A, Sangsuwan T, Bendes A, Hong MG, Qundos U, Harms-Ringdahl M, Wersäll P, Polanska J, Schwenk JM, Haghdoost S. Molecular Profiling for Predictors of Radiosensitivity in Patients with Breast or Head-and-Neck Cancer. Cancers (Basel) 2020; 12:cancers12030753. [PMID: 32235817 PMCID: PMC7140105 DOI: 10.3390/cancers12030753] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Revised: 03/13/2020] [Accepted: 03/16/2020] [Indexed: 02/07/2023] Open
Abstract
Nearly half of all cancers are treated with radiotherapy alone or in combination with other treatments, where damage to normal tissues is a limiting factor for the treatment. Radiotherapy-induced adverse health effects, mostly of importance for cancer patients with long-term survival, may appear during or long time after finishing radiotherapy and depend on the patient’s radiosensitivity. Currently, there is no assay available that can reliably predict the individual’s response to radiotherapy. We profiled two study sets from breast (n = 29) and head-and-neck cancer patients (n = 74) that included radiosensitive patients and matched radioresistant controls.. We studied 55 single nucleotide polymorphisms (SNPs) in 33 genes by DNA genotyping and 130 circulating proteins by affinity-based plasma proteomics. In both study sets, we discovered several plasma proteins with the predictive power to find radiosensitive patients (adjusted p < 0.05) and validated the two most predictive proteins (THPO and STIM1) by sandwich immunoassays. By integrating genotypic and proteomic data into an analysis model, it was found that the proteins CHIT1, PDGFB, PNKD, RP2, SERPINC1, SLC4A, STIM1, and THPO, as well as the VEGFA gene variant rs69947, predicted radiosensitivity of our breast cancer (AUC = 0.76) and head-and-neck cancer (AUC = 0.89) patients. In conclusion, circulating proteins and a SNP variant of VEGFA suggest that processes such as vascular growth capacity, immune response, DNA repair and oxidative stress/hypoxia may be involved in an individual’s risk of experiencing radiation-induced toxicity.
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Affiliation(s)
- Kimi Drobin
- Affinity Proteomics, Science for Life Laboratory, Department of Protein Science, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH – Royal Institute of Technology, Tomtebodavägen 23, 171 65 Stockholm, Sweden; (K.D.); (A.B.); (M.-G.H.); (U.Q.); (J.M.S.)
| | - Michal Marczyk
- Yale Cancer Center, Department of Internal Medicine, Yale University School of Medicine, 06511 New Haven, CT, USA;
- Department of Data Science and Engineering, Silesian University of Technology, 44-100 Gliwice, Poland; (A.P.); (J.P.)
| | - Martin Halle
- Department of Molecular Medicine and Surgery, Karolinska Institutet, 17176, Stockholm, Sweden;
- Reconstructive Plastic Surgery, Karolinska University Hospital, 17176 Stockholm, Sweden
| | - Daniel Danielsson
- Department of Clinical Science, Intervention and Technology, Division of ENT Diseases, Karolinska Institutet, 14186 Stockholm, Sweden;
- Department of Oral and Maxillofacial Surgery, Karolinska University Hospital, 17176, Stockholm, Sweden
| | - Anna Papiez
- Department of Data Science and Engineering, Silesian University of Technology, 44-100 Gliwice, Poland; (A.P.); (J.P.)
| | - Traimate Sangsuwan
- Centre for Radiation Protection Research, Department of Molecular Biosciences, The Wenner-Gren Institute Stockholm University, 10691 Stockholm, Sweden; (T.S.); (M.H.-R.)
| | - Annika Bendes
- Affinity Proteomics, Science for Life Laboratory, Department of Protein Science, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH – Royal Institute of Technology, Tomtebodavägen 23, 171 65 Stockholm, Sweden; (K.D.); (A.B.); (M.-G.H.); (U.Q.); (J.M.S.)
| | - Mun-Gwan Hong
- Affinity Proteomics, Science for Life Laboratory, Department of Protein Science, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH – Royal Institute of Technology, Tomtebodavägen 23, 171 65 Stockholm, Sweden; (K.D.); (A.B.); (M.-G.H.); (U.Q.); (J.M.S.)
| | - Ulrika Qundos
- Affinity Proteomics, Science for Life Laboratory, Department of Protein Science, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH – Royal Institute of Technology, Tomtebodavägen 23, 171 65 Stockholm, Sweden; (K.D.); (A.B.); (M.-G.H.); (U.Q.); (J.M.S.)
| | - Mats Harms-Ringdahl
- Centre for Radiation Protection Research, Department of Molecular Biosciences, The Wenner-Gren Institute Stockholm University, 10691 Stockholm, Sweden; (T.S.); (M.H.-R.)
| | - Peter Wersäll
- Department of Radiotherapy, Karolinska University Hospital, 17176 Stockholm, Sweden;
| | - Joanna Polanska
- Department of Data Science and Engineering, Silesian University of Technology, 44-100 Gliwice, Poland; (A.P.); (J.P.)
| | - Jochen M. Schwenk
- Affinity Proteomics, Science for Life Laboratory, Department of Protein Science, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH – Royal Institute of Technology, Tomtebodavägen 23, 171 65 Stockholm, Sweden; (K.D.); (A.B.); (M.-G.H.); (U.Q.); (J.M.S.)
| | - Siamak Haghdoost
- Centre for Radiation Protection Research, Department of Molecular Biosciences, The Wenner-Gren Institute Stockholm University, 10691 Stockholm, Sweden; (T.S.); (M.H.-R.)
- University of Caen Normandy, Department of medicine, Cimap-Laria, Advanced Resource Center for HADrontherapy in Europe (ARCHADE), 14076 Caen, France
- Correspondence:
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30
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Chloride transporters and channels in β-cell physiology: revisiting a 40-year-old model. Biochem Soc Trans 2020; 47:1843-1855. [PMID: 31697318 PMCID: PMC6925527 DOI: 10.1042/bst20190513] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Revised: 10/14/2019] [Accepted: 10/17/2019] [Indexed: 12/13/2022]
Abstract
It is accepted that insulin-secreting β-cells release insulin in response to glucose even in the absence of functional ATP-sensitive K+ (KATP)-channels, which play a central role in a 'consensus model' of secretion broadly accepted and widely reproduced in textbooks. A major shortcoming of this consensus model is that it ignores any and all anionic mechanisms, known for more than 40 years, to modulate β-cell electrical activity and therefore insulin secretion. It is now clear that, in addition to metabolically regulated KATP-channels, β-cells are equipped with volume-regulated anion (Cl-) channels (VRAC) responsive to glucose concentrations in the range known to promote electrical activity and insulin secretion. In this context, the electrogenic efflux of Cl- through VRAC and other Cl- channels known to be expressed in β-cells results in depolarization because of an outwardly directed Cl- gradient established, maintained and regulated by the balance between Cl- transporters and channels. This review will provide a succinct historical perspective on the development of a complex hypothesis: Cl- transporters and channels modulate insulin secretion in response to nutrients.
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Abstract
Metabolism is a continuous source of acids. To keep up with a desired metabolic rate, tumors must establish an adequate means of clearing their acidic end-products. This homeostatic priority is achieved by various buffers, enzymes, and transporters connected through the common denominator of H+ ions. Whilst this complexity is proportionate to the importance of adequate pH control, it is problematic for developing an intuition for tracking the route taken by acids, assessing the relative importance of various acid-handling proteins, and predicting the outcomes of pharmacological inhibition or genetic alteration. Here, with the help of a simplified mathematical framework, the genesis of cancer pH regulation is explained in terms of the obstacles to efficient acid venting and how these are overcome by specific molecules, often associated with cancer. Ultimately, the pH regulatory apparatus in tumors must (i) provide adequate lactic acid permeability through membranes, (ii) facilitate CO2/HCO3−/H+ diffusivity across the interstitium, (iii) invest in a form of active transport that strikes a favorable balance between intracellular pH and intracellular lactate retention under the energetic constraints of a cell, and (iv) enable the necessary feedback to complete the homeostatic loop. A more informed and quantitative approach to understanding acid-handling in cancer is mandatory for identifying vulnerabilities, which could be exploited as therapeutic targets.
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Affiliation(s)
- Pawel Swietach
- Department of Physiology, Anatomy and Genetics, Parks Road, Oxford, OX1 3PT, England.
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32
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Gulamhusein AF, Hirschfield GM, Milovanovic J, Arsenijevic D, Arsenijevic N, Milovanovic M. Primary biliary cholangitis: pathogenesis and therapeutic opportunities. Nat Rev Gastroenterol Hepatol 2020; 17:93-110. [PMID: 31819247 DOI: 10.1038/s41575-019-0226-7] [Citation(s) in RCA: 156] [Impact Index Per Article: 39.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 10/09/2019] [Indexed: 02/08/2023]
Abstract
Primary biliary cholangitis is a chronic, seropositive and female-predominant inflammatory and cholestatic liver disease, which has a variable rate of progression towards biliary cirrhosis. Substantial progress has been made in patient risk stratification with the goal of personalized care, including early adoption of next-generation therapy with licensed use of obeticholic acid or off-label fibrate derivatives for those with insufficient benefit from ursodeoxycholic acid, the current first-line drug. The disease biology spans genetic risk, epigenetic changes, dysregulated mucosal immunity and altered biliary epithelial cell function, all of which interact and arise in the context of ill-defined environmental triggers. A current focus of research on nuclear receptor pathway modulation that specifically and potently improves biliary excretion, reduces inflammation and attenuates fibrosis is redefining therapy. Patients are benefiting from pharmacological agonists of farnesoid X receptor and peroxisome proliferator-activated receptors. Immunotherapy remains a challenge, with a lack of target definition, pleiotropic immune pathways and an interplay between hepatic immune responses and cholestasis, wherein bile acid-induced inflammation and fibrosis are dominant clinically. The management of patient symptoms, particularly pruritus, is a notable goal reflected in the development of rational therapy with apical sodium-dependent bile acid transporter inhibitors.
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Affiliation(s)
- Aliya F Gulamhusein
- Toronto Centre for Liver Disease, University Health Network and Department of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Gideon M Hirschfield
- Toronto Centre for Liver Disease, University Health Network and Department of Medicine, University of Toronto, Toronto, Ontario, Canada.
| | - Jelena Milovanovic
- Center for Molecular Medicine and Stem Cell Research, Faculty of Medical Sciences, University of Kragujevac, Kragujevac 34000, Serbia.,Department of Histology, Faculty of Medical Sciences, University of Kragujevac, Kragujevac 34000, Serbia
| | - Dragana Arsenijevic
- Department of Pharmacy, Faculty of Medical Sciences, University of Kragujevac, Kragujevac 34000, Serbia
| | - Nebojsa Arsenijevic
- Center for Molecular Medicine and Stem Cell Research, Faculty of Medical Sciences, University of Kragujevac, Kragujevac 34000, Serbia
| | - Marija Milovanovic
- Center for Molecular Medicine and Stem Cell Research, Faculty of Medical Sciences, University of Kragujevac, Kragujevac 34000, Serbia
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33
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Becker HM. Carbonic anhydrase IX and acid transport in cancer. Br J Cancer 2020; 122:157-167. [PMID: 31819195 PMCID: PMC7051959 DOI: 10.1038/s41416-019-0642-z] [Citation(s) in RCA: 94] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 08/29/2019] [Accepted: 10/22/2019] [Indexed: 02/07/2023] Open
Abstract
Alterations in tumour metabolism and acid/base regulation result in the formation of a hostile environment, which fosters tumour growth and metastasis. Acid/base homoeostasis in cancer cells is governed by the concerted interplay between carbonic anhydrases (CAs) and various transport proteins, which either mediate proton extrusion or the shuttling of acid/base equivalents, such as bicarbonate and lactate, across the cell membrane. Accumulating evidence suggests that some of these transporters interact both directly and functionally with CAIX to form a protein complex coined the 'transport metabolon'. Transport metabolons formed between bicarbonate transporters and CAIX require CA catalytic activity and have a function in cancer cell migration and invasion. Another type of transport metabolon is formed by CAIX and monocarboxylate transporters. In this complex, CAIX functions as a proton antenna for the transporter, which drives the export of lactate and protons from the cell. Since CAIX is almost exclusively expressed in cancer cells, these transport metabolons might serve as promising targets to interfere with tumour pH regulation and energy metabolism. This review provides an overview of the current state of research on the function of CAIX in tumour acid/base transport and discusses how CAIX transport metabolons could be exploited in modern cancer therapy.
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Affiliation(s)
- Holger M Becker
- Institute of Physiological Chemistry, University of Veterinary Medicine Hannover, D-30559, Hannover, Germany.
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34
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Bernardino RL, Carrageta DF, Sousa M, Alves MG, Oliveira PF. pH and male fertility: making sense on pH homeodynamics throughout the male reproductive tract. Cell Mol Life Sci 2019; 76:3783-3800. [PMID: 31165202 PMCID: PMC11105638 DOI: 10.1007/s00018-019-03170-w] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2018] [Revised: 04/24/2019] [Accepted: 05/29/2019] [Indexed: 02/07/2023]
Abstract
In the male reproductive tract, ionic equilibrium is essential to maintain normal spermatozoa production and, hence, the reproductive potential. Among the several ions, HCO3- and H+ have a central role, mainly due to their role on pH homeostasis. In the male reproductive tract, the major players in pH regulation and homeodynamics are carbonic anhydrases (CAs), HCO3- membrane transporters (solute carrier 4-SLC4 and solute carrier 26-SLC26 family transporters), Na+-H+ exchangers (NHEs), monocarboxylate transporters (MCTs) and voltage-gated proton channels (Hv1). CAs and these membrane transporters are widely distributed throughout the male reproductive tract, where they play essential roles in the ionic balance of tubular fluids. CAs are the enzymes responsible for the production of HCO3- which is then transported by membrane transporters to ensure the maturation, storage, and capacitation of the spermatozoa. The transport of H+ is carried out by NHEs, Hv1, and MCTs and is essential for the electrochemical balance and for the maintenance of the pH within the physiological limits along the male reproductive tract. Alterations in HCO3- production and transport of ions have been associated with some male reproductive dysfunctions. Herein, we present an up-to-date review on the distribution and role of the main intervenient on pH homeodynamics in the fluids throughout the male reproductive tract. In addition, we discuss their relevance for the establishment of the male reproductive potential.
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Affiliation(s)
- Raquel L Bernardino
- Laboratory of Cell Biology, Department of Microscopy, Institute of Biomedical Sciences Abel Salazar and Unit for Multidisciplinary Research in Biomedicine, University of Porto, Porto, Portugal
| | - David F Carrageta
- Laboratory of Cell Biology, Department of Microscopy, Institute of Biomedical Sciences Abel Salazar and Unit for Multidisciplinary Research in Biomedicine, University of Porto, Porto, Portugal
| | - Mário Sousa
- Laboratory of Cell Biology, Department of Microscopy, Institute of Biomedical Sciences Abel Salazar and Unit for Multidisciplinary Research in Biomedicine, University of Porto, Porto, Portugal
| | - Marco G Alves
- Institute of Biomedical Sciences Abel Salazar and Unit for Multidisciplinary Research in Biomedicine, University of Porto, Porto, Portugal
| | - Pedro F Oliveira
- Laboratory of Cell Biology, Department of Microscopy, Institute of Biomedical Sciences Abel Salazar and Unit for Multidisciplinary Research in Biomedicine, University of Porto, Porto, Portugal.
- i3S-Institute for Innovation and Health Research, University of Porto, Porto, Portugal.
- Department of Genetics, Faculty of Medicine, University of Porto, Porto, Portugal.
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35
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De Vecchis D, Reithmeier RAF, Kalli AC. Molecular Simulations of Intact Anion Exchanger 1 Reveal Specific Domain and Lipid Interactions. Biophys J 2019; 117:1364-1379. [PMID: 31540709 PMCID: PMC6818359 DOI: 10.1016/j.bpj.2019.08.029] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Revised: 07/30/2019] [Accepted: 08/22/2019] [Indexed: 12/23/2022] Open
Abstract
Anion exchanger 1 (AE1) is responsible for the exchange of bicarbonate and chloride across the erythrocyte plasma membrane. Human AE1 consists of a cytoplasmic and a membrane domain joined by a 33-residue flexible linker. Crystal structures of the individual domains have been determined, but the intact AE1 structure remains elusive. In this study, we use molecular dynamics simulations and modeling to build intact AE1 structures in a complex lipid bilayer that resembles the native erythrocyte plasma membrane. AE1 models were evaluated using available experimental data to provide an atomistic view of the interaction and dynamics of the cytoplasmic domain, the membrane domain, and the connecting linker in a complete model of AE1 in a lipid bilayer. Anionic lipids were found to interact strongly with AE1 at specific amino acid residues that are linked to diseases and blood group antigens. Cholesterol was found in the dimeric interface of AE1, suggesting that it may regulate subunit interactions and anion transport.
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Affiliation(s)
- Dario De Vecchis
- Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, Leeds, United Kingdom
| | | | - Antreas C Kalli
- Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, Leeds, United Kingdom; Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, United Kingdom.
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36
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Rao MC. Physiology of Electrolyte Transport in the Gut: Implications for Disease. Compr Physiol 2019; 9:947-1023. [PMID: 31187895 DOI: 10.1002/cphy.c180011] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
We now have an increased understanding of the genetics, cell biology, and physiology of electrolyte transport processes in the mammalian intestine, due to the availability of sophisticated methodologies ranging from genome wide association studies to CRISPR-CAS technology, stem cell-derived organoids, 3D microscopy, electron cryomicroscopy, single cell RNA sequencing, transgenic methodologies, and tools to manipulate cellular processes at a molecular level. This knowledge has simultaneously underscored the complexity of biological systems and the interdependence of multiple regulatory systems. In addition to the plethora of mammalian neurohumoral factors and their cross talk, advances in pyrosequencing and metagenomic analyses have highlighted the relevance of the microbiome to intestinal regulation. This article provides an overview of our current understanding of electrolyte transport processes in the small and large intestine, their regulation in health and how dysregulation at multiple levels can result in disease. Intestinal electrolyte transport is a balance of ion secretory and ion absorptive processes, all exquisitely dependent on the basolateral Na+ /K+ ATPase; when this balance goes awry, it can result in diarrhea or in constipation. The key transporters involved in secretion are the apical membrane Cl- channels and the basolateral Na+ -K+ -2Cl- cotransporter, NKCC1 and K+ channels. Absorption chiefly involves apical membrane Na+ /H+ exchangers and Cl- /HCO3 - exchangers in the small intestine and proximal colon and Na+ channels in the distal colon. Key examples of our current understanding of infectious, inflammatory, and genetic diarrheal diseases and of constipation are provided. © 2019 American Physiological Society. Compr Physiol 9:947-1023, 2019.
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Affiliation(s)
- Mrinalini C Rao
- Department of Physiology and Biophysics, University of Illinois at Chicago, Chicago, Illinois, USA
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37
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Bonnet U, Bingmann D, Speckmann EJ, Wiemann M. Levetiracetam mediates subtle pH-shifts in adult human neocortical pyramidal cells via an inhibition of the bicarbonate-driven neuronal pH-regulation - Implications for excitability and plasticity modulation. Brain Res 2019; 1710:146-156. [PMID: 30590026 DOI: 10.1016/j.brainres.2018.12.039] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Revised: 11/24/2018] [Accepted: 12/23/2018] [Indexed: 01/20/2023]
Abstract
The intracellular pH (pHi) of mammalian central neurons is tightly regulated and small pHi-fluctuations can fine-tune inter-/intracellular signaling, excitability, and synaptic plasticity. The research-gap about the pHi-regulation of human brain neurons is addressed here by testing possible influences of the anticonvulsant levetiracetam (LEV). BCECF-AM-loaded neocortical pyramidal cells were fluorometrically investigated in slice-preparations of tissue resected from the middle temporal gyrus of five adults with intractable temporal-lobe epilepsy. Recovery-slope from intracellular acidification following an ammonium prepulse (APP) was used to measure the pHi-regulation. Among twenty pyramidal cells exposed to 50 μM LEV, the resting pHi (7.09 ± 0.14) was lowered in eight (40%) neurons, on average by 0.02 ± 0.011 pH-units. In three (15%) and nine (45%) neurons, a minimal alkaline shift (0.017 ± 0.004 pH-units) and no pHi-shift occurred, respectively. The LEV-induced pHi-shifts were positively correlated with the resting pHi (r = 0.6, p = 0.006, n = 20). In five neurons, which all had responded on LEV with an acidification before, the recovery from APP-acidification was significantly delayed during LEV (p < 0.001). This inhibitory LEV-effect on pHi-regulation i) was similar to that of 200 μM 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (n = 2) and ii) did not occur under nominal bicarbonate-free conditions (n = 2). Thus, LEV lowered the pHi of human neocortical pyramidal cells most likely by a weakening of the transmembrane HCO3(-)-mediated acid-extrusion. This might contribute to LEV's anticonvulsive potency. Neurons with more acidic resting pHi-values showed a minimal alkalization upon LEV providing a mechanism for paradoxical proconvulsive LEV-effects rarely observed in epilepsy patients. The significance of these subtle pHi-shifts for cortical excitability and plasticity is discussed.
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Affiliation(s)
- Udo Bonnet
- Department of Psychiatry, Psychotherapy, and Psychosomatic Medicine, Evangelisches Krankenhaus Castrop-Rauxel, Academic Teaching Hospital of the University Duisburg-Essen, Castrop-Rauxel, Germany; Department of Psychiatry and Psychotherapy, Faculty of Medicine, LVR-Hospital Essen, University of Duisburg-Essen, Essen, Germany.
| | - Dieter Bingmann
- Institute of Physiology, University of Duisburg-Essen, Essen, Germany
| | | | - Martin Wiemann
- Institute of Physiology, University of Duisburg-Essen, Essen, Germany; IBE R&D gGmbH, Institute for Lung Health, D-48149 Münster, Germany
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38
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Wang Y, Wang X, Chen S, Tian X, Zhang L, Huang Y, Tang C, Du J, Jin H. Sulfur Dioxide Activates Cl -/HCO 3 - Exchanger via Sulphenylating AE2 to Reduce Intracellular pH in Vascular Smooth Muscle Cells. Front Pharmacol 2019; 10:313. [PMID: 30971931 PMCID: PMC6446831 DOI: 10.3389/fphar.2019.00313] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2018] [Accepted: 03/14/2019] [Indexed: 12/28/2022] Open
Abstract
Sulfur dioxide (SO2) is a colorless and irritating gas. Recent studies indicate that SO2 acts as the gas signal molecule and inhibits vascular smooth muscle cell (VSMC) proliferation. Cell proliferation depends on intracellular pH (pHi). Transmembrane cystein mutation of Na+- independent Cl-/HCO3 - exchanger (anion exchanger, AE) affects pHi. However, whether SO2 inhibits VSMC proliferation by reducing pHi is still unknown. Here, we investigated whether SO2 reduced pHi to inhibit the proliferation of VSMCs and explore its molecular mechanisms. Within a range of 50-200 μM, SO2 was found to lower the pHi in VSMCs. Concurrently, NH4Cl pre-perfusion showed that SO2 significantly activated AE, whereas the AE inhibitor 4,4'-diisothiocyanatostilbene- 2,20-disulfonic acid (DIDS) significantly attenuated the effect of SO2 on pHi in VSMCs. While 200 μM SO2 sulphenylated AE2, while dithiothreitol (DTT) blocked the sulphenylation of AE2 and subsequent AE activation by SO2, thereby restoring the pHi in VSMCs. Furthermore, DIDS pretreatment eliminated SO2-induced inhibition of PDGF-BB-stimulated VSMC proliferation. We report for the first time that SO2 inhibits VSMC proliferation in part by direct activation of the AE via posttranslational sulphenylation and induction of intracellular acidification.
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Affiliation(s)
- Yi Wang
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Xiuli Wang
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Selena Chen
- Division of Biological Sciences, University of California, San Diego, La Jolla, CA, United States
| | - Xiaoyu Tian
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Lulu Zhang
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Yaqian Huang
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Chaoshu Tang
- Department of Physiology and Pathophysiology, Peking University Health Science Center, Beijing, China.,Key Laboratory of Molecular Cardiology, Ministry of Education, Beijing, China
| | - Junbao Du
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Hongfang Jin
- Department of Pediatrics, Peking University First Hospital, Beijing, China
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39
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Hepatocyte nuclear factor 4α regulates megalin expression in proximal tubular cells. Biochem Biophys Rep 2018; 17:87-92. [PMID: 30582012 PMCID: PMC6295598 DOI: 10.1016/j.bbrep.2018.11.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Revised: 11/27/2018] [Accepted: 11/28/2018] [Indexed: 01/05/2023] Open
Abstract
Hepatocyte nuclear factor 4α (HNF4α) is a member of the nuclear receptor superfamily and upregulates expression of many genes in the liver, pancreas, small intestine, and colon. HNF4α is also highly expressed in proximal tubular epithelial cells (PTECs) in kidney. PTECs reabsorb various substances through transporters, ion channels, and receptors, but the target genes for HNF4α in PTECs have not been investigated in detail. In the present study, we aimed to identify novel HNF4α target genes that are highly expressed in PTECs. Expression of many solute carrier transporter genes was upregulated by HNF4α in human PTEC-derived HK-2 cells. Notably, expression of megalin (LRP2), an endocytic receptor of various molecules involved in development and progression of chronic kidney disease (CKD), was strongly induced by HNF4α, and the transactivation potential of the megalin promoter was dependent on HNF4α expression. Moreover, HNF4α was found to directly bind to an HNF4α binding site near the transcription start site in the megalin gene. These results indicate that HNF4α plays an important role in maintaining reabsorption and metabolism in PTECs by positive regulation of several solute carrier transporter and megalin genes at the transcriptional level. HNF4α upregulates expression of several SLC transporters that are highly expressed in proximal tubular epithelial cells. HNF4α upregulates expression of magalin, multifunctional endocytic receptor in human proximal tubular epithelial cells. Transactivation of megalin gene is dependent on HNF4α expression and an HNF4α binding site in the megalin promoter.
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40
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Watanabe T. Improving outcomes for patients with distal renal tubular acidosis: recent advances and challenges ahead. PEDIATRIC HEALTH MEDICINE AND THERAPEUTICS 2018; 9:181-190. [PMID: 30588151 PMCID: PMC6296208 DOI: 10.2147/phmt.s174459] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Primary distal renal tubular acidosis (dRTA) is a rare genetic disorder caused by impaired distal acidification due to a failure of type A intercalated cells (A-ICs) in the collecting tubule. dRTA is characterized by persistent hyperchloremia, a normal plasma anion gap, and the inability to maximally lower urinary pH in the presence of systemic metabolic acidosis. Common clinical features of dRTA include vomiting, failure to thrive, polyuria, hypercalciuria, hypocitraturia, nephrocalcinosis, nephrolithiasis, growth delay, and rickets. Mutations in genes encoding three distinct transport proteins in A-ICs have been identified as causes of dRTA, including the B1/ATP6V1B1 and a4/ATP6V0A4 subunits of the vacuolar-type H+-ATPase (H+-ATPase) and the chloride–bicarbonate exchanger AE1/SLC4A1. Homozygous or compound heterozygous mutations in ATP6V1B1 and ATP6V0A4 lead to autosomal recessive (AR) dRTA. dRTA caused by SLC4A1 mutations can occur with either autosomal dominant or AR transmission. Red blood cell abnormalities have been associated with AR dRTA due to SLC4A1 mutations, including hereditary spherocytosis, Southeast Asia ovalocytosis, and others. Some patients with dRTA exhibit atypical clinical features, including transient and reversible proximal tubular dysfunction and hyperammonemia. Incomplete dRTA presents with inadequate urinary acidification, but without spontaneous metabolic acidosis and recurrent urinary stones. Heterozygous mutations in the AE1 or H+-ATPase genes have recently been reported in patients with incomplete dRTA. Early and sufficient doses of alkali treatment are needed for patients with dRTA. Normalized serum bicarbonate, urinary calcium excretion, urinary low-molecular-weight protein levels, and growth rate are good markers of adherence to and/or efficacy of treatment. The prognosis of dRTA is generally good in patients with appropriate treatment. However, recent studies showed an increased frequency of chronic kidney disease (CKD) in patients with dRTA during long-term follow-up. The precise pathogenic mechanisms of CKD in patients with dRTA are unknown.
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Affiliation(s)
- Toru Watanabe
- Department of Pediatrics, Niigata City General Hospital, Niigata City 950-1197, Japan,
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41
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Wu C, Liu X, Sun R, Qin Y, Liu Z, Yang S, Tang T, Zhu Z, Yu D, Liu F. Targeting Anion Exchange of Osteoclast, a New Strategy for Preventing Wear Particles Induced- Osteolysis. Front Pharmacol 2018; 9:1291. [PMID: 30459624 PMCID: PMC6232501 DOI: 10.3389/fphar.2018.01291] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Accepted: 10/22/2018] [Indexed: 12/30/2022] Open
Abstract
Joint replacement is essential for the treatment of serious joint disease. However, prosthetic failure remains an important clinical issue, with periprosthesis osteolysis (PO), caused by osteoclastic bone resorption induced by wear particles, being the leading cause of failure. Nuclear factor of activated T cells c1 (NFATc1) appears to play an important role in wear particle-induced osteoclastogenesis, with bicarbonate/chloride exchanger, solute carrier family 4, anion exchanger, member 2, (SLC4A2) being upregulated during osteoclastogenesis in an NFATc1-dependent manner. Anion exchange mediated by SLC4A2 in osteoclasts could affect the bone resorption activity by regulating pHi. This study investigated the role and mechanism of SLC4A2 in wear particle-induced osteoclast differentiation and function in vitro. The use of 4, 4'-diisothiocyano-2,2'-stilbenedisulfonic acid (DIDS), an anion exchange inhibitor, suppressed wear particle-induced PO in vivo. Furthermore, controlled release of DIDS from chitosan microspheres can strengthen the PO therapy effect. Therefore, anion exchange mediated by osteoclastic SLC4A2 may be a potential therapeutic target for the treatment of aseptic loosening of artificial joints.
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Affiliation(s)
- Chuanlong Wu
- Shanghai Key Laboratory of Orthopaedic Implants, Department of Orthopaedics, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Department of Orthopaedics, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Xuqiang Liu
- Department of Orthopaedics, The First Affiliated Hospital, Nanchang University, Nanchang, China
| | - Ruixin Sun
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yunhao Qin
- Department of Orthopaedics, Sixth People's Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Zhiqing Liu
- Shanghai Key Laboratory of Orthopaedic Implants, Department of Orthopaedics, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Shengbing Yang
- Shanghai Key Laboratory of Orthopaedic Implants, Department of Orthopaedics, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Tingting Tang
- Shanghai Key Laboratory of Orthopaedic Implants, Department of Orthopaedics, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Zhenan Zhu
- Shanghai Key Laboratory of Orthopaedic Implants, Department of Orthopaedics, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Degang Yu
- Shanghai Key Laboratory of Orthopaedic Implants, Department of Orthopaedics, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Fengxiang Liu
- Shanghai Key Laboratory of Orthopaedic Implants, Department of Orthopaedics, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
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42
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Gulamhusein AF, Hirschfield GM. Pathophysiology of primary biliary cholangitis. Best Pract Res Clin Gastroenterol 2018; 34-35:17-25. [PMID: 30343706 DOI: 10.1016/j.bpg.2018.05.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Accepted: 05/22/2018] [Indexed: 01/31/2023]
Abstract
Primary biliary cholangitis is a prototypical autoimmune disease characterized by an overwhelming female predominance, a distinct clinical phenotype, and disease specific anti-mitochondrial antibodies targeted against a well-defined auto-antigen. In a genetically susceptible host, multi-lineage loss of tolerance to the E2 component of the 2-oxo-dehydrogenase pathway and dysregulated immune pathways directed at biliary epithelial cells leads to cholestasis, progressive biliary fibrosis, and cirrhosis in a subset of patients. Several key insights have shed light on the complex pathogenesis of disease. First, characteristic anti-mitochondrial antibodies (AMAs) target lipoic acid containing immunodominant epitopes, particularly pyruvate dehydrogenase complex (PDC-E2), on the inner mitochondrial membrane of BECs. Next, breakdown of the protective apical bicarbonate rich umbrella may sensitize BECs to aberrant apoptotic pathways leaving the antigenic PDC-E2 epitope immunologically tact within an apoptotic bleb. A multi-lineage immune response ensues characterized by an imbalance between effector and regulatory activity resulting in progressive and self-perpetuating biliary injury. Genome wide studies shed light on important pathways involved in disease, key among them being IL-12. Epigenetic mechanisms and microRNAs may play help shed light on the missing heritability and female preponderance of disease. Taken together, these findings have dramatically advanced our understanding of disease and may lead to important therapeutic advances.
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Affiliation(s)
- Aliya F Gulamhusein
- Toronto Centre for Liver Disease, 200 Elizabeth Street, Toronto, ON, Canada.
| | - Gideon M Hirschfield
- Centre for Liver Research and NIHR Birmingham Biomedical Research Centre, University of Birmingham, Birmingham, UK.
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43
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Shah K, Raghavan S, Hou Z, Matherly LH, Gangjee A. Development and validation of chemical features-based proton-coupled folate transporter/activity and reduced folate carrier/activity models (pharmacophores). J Mol Graph Model 2018; 81:125-133. [PMID: 29550744 PMCID: PMC5959037 DOI: 10.1016/j.jmgm.2018.02.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Revised: 02/09/2018] [Accepted: 02/12/2018] [Indexed: 10/18/2022]
Abstract
All clinically used antifolates lack transport selectivity for tumors over normal cells resulting in dose-limiting toxicities. There is growing interest in developing novel tumor-targeted cytotoxic antifolates with selective transport into tumors over normal cells via the proton-coupled folate transporter (PCFT) over the ubiquitously expressed reduced folate carrier (RFC). A lack of X-ray crystal structures or predictive models for PCFT or RFC has hindered structure-aided drug design for PCFT-selective therapeutics. Four-point validated models (pharmacophores) were generated for PCFT/Activity (HBA, NI, RA, RA) and RFC/Activity (HBD, NI, HBA, HBA) based on inhibition (IC50) of proliferation of isogenic Chinese hamster ovary (CHO) cells engineered to express only human PCFT or only RFC. Our results revealed substantial differences in structural features required for transport of novel molecules by these transporters which can be utilized for developing transporter-selective antifolates.
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Affiliation(s)
- Khushbu Shah
- Division of Medicinal Chemistry, Graduate School of Pharmaceutical Sciences, Duquesne University, 600 Forbes Avenue, Pittsburgh, PA 15282, United States
| | - Sudhir Raghavan
- Division of Medicinal Chemistry, Graduate School of Pharmaceutical Sciences, Duquesne University, 600 Forbes Avenue, Pittsburgh, PA 15282, United States
| | - Zhanjun Hou
- Molecular Therapeutics Program, Barbara Ann Karmanos Cancer Institute, and Department of Oncology, Wayne State University School of Medicine, 421 East Canfield Street, Detroit, MI 48201, United States
| | - Larry H Matherly
- Molecular Therapeutics Program, Barbara Ann Karmanos Cancer Institute, and Department of Oncology, Wayne State University School of Medicine, 421 East Canfield Street, Detroit, MI 48201, United States
| | - Aleem Gangjee
- Division of Medicinal Chemistry, Graduate School of Pharmaceutical Sciences, Duquesne University, 600 Forbes Avenue, Pittsburgh, PA 15282, United States.
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44
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Parker MD. Mouse models of SLC4-linked disorders of HCO 3--transporter dysfunction. Am J Physiol Cell Physiol 2018; 314:C569-C588. [PMID: 29384695 DOI: 10.1152/ajpcell.00301.2017] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The SLC4 family Cl-/[Formula: see text] cotransporters (NBCe1, NBCe2, NBCn1, and NBCn2) contribute to a variety of vital physiological processes including pH regulation and epithelial fluid secretion. Accordingly, their dysfunction can have devastating effects. Disorders such as epilepsy, hemolytic anemia, glaucoma, hearing loss, osteopetrosis, and renal tubular acidosis are all genetically linked to SLC4-family gene loci. This review summarizes how studies of Slc4-modified mice have enhanced our understanding of the etiology of SLC4-linked pathologies and the interpretation of genetic linkage studies. The review also surveys the novel disease signs exhibited by Slc4-modified mice which could either be considered to presage their description in humans, or to highlight interspecific differences. Finally, novel Slc4-modified mouse models are proposed, the study of which may further our understanding of the basis and treatment of SLC4-linked disorders of [Formula: see text]-transporter dysfunction.
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Affiliation(s)
- Mark D Parker
- Department of Physiology and Biophysics, The State University of New York: The University at Buffalo , Buffalo, New York.,Department of Ophthalmology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo: The State University of New York , Buffalo, New York.,State University of New York Eye Institutes, University at Buffalo: The State University of New York , Buffalo, New York
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45
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Pérez-Rodríguez MJ, Velazquez-Lagunas I, Pluma-Pluma A, Barragán-Iglesias P, Granados-Soto V. Anion exchanger 3 in dorsal root ganglion contributes to nerve injury-induced chronic mechanical allodynia and thermal hyperalgesia. J Pharm Pharmacol 2018; 70:374-382. [DOI: 10.1111/jphp.12868] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Accepted: 11/25/2017] [Indexed: 12/21/2022]
Abstract
Abstract
Objective
To determine the role of anion exchanger 3 (AE3) in dorsal root ganglion (DRG) in nerve injury-induced chronic nociception in the rat.
Methods
Spared nerve injury (SNI) was used to induce neuropathic pain. Von Frey filaments and Hargreaves test were used to assess tactile allodynia and thermal hyperalgesia, respectively. Drugs were given by intrathecal administration. Western blotting was used to determine AE3 expression in DRG.
Key findings
SNI produced long-lasting mechanical allodynia and thermal hyperalgesia. AE3 was found in DRG of sham-operated rats. SNI enhanced baseline AE3 expression in L4 and L5 DRGs at days 7 and 14, respectively. In contrast, SNI did not affect AE3 expression in L6 DRG. AE3 expression returned to baseline levels 21 days after SNI. Intrathecal 4,4′-diisothiocyanatostilbene-2,2′-disulfonic acid (DIDS) (5–50 μg) pretreatment prevented SNI-induced allodynia and, at a lesser extent, hyperalgesia. Moreover, DIDS (50 μg) reduced SNI-induced AE3 upregulation in L4, but not L5, DRGs. Intrathecal DIDS (5–50 μg) or anti-AE3 antibody (1 μg), but not vehicle, post-treatment (6 days) partially reversed SNI-induced allodynia and hyperalgesia. DIDS or anti-AE3 antibody post-treatment diminished SNI-induced AE3 upregulation in L4 and L5 DRGs.
Conclusions
Data suggest that AE3 is present in DRG and contributes to mechanical allodynia and thermal hyperalgesia in neuropathic rats.
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Affiliation(s)
- Marian J Pérez-Rodríguez
- Neurobiology of Pain Laboratory, Departamento de Farmacobiología, Cinvestav, Unidad Coapa, Ciudad de México, Mexico
| | - Isabel Velazquez-Lagunas
- Neurobiology of Pain Laboratory, Departamento de Farmacobiología, Cinvestav, Unidad Coapa, Ciudad de México, Mexico
| | - Alejandro Pluma-Pluma
- Neurobiology of Pain Laboratory, Departamento de Farmacobiología, Cinvestav, Unidad Coapa, Ciudad de México, Mexico
| | - Paulino Barragán-Iglesias
- Neurobiology of Pain Laboratory, Departamento de Farmacobiología, Cinvestav, Unidad Coapa, Ciudad de México, Mexico
- School of Behavioral and Brain Sciences, University of Texas at Dallas, Dallas, TX, USA
| | - Vinicio Granados-Soto
- Neurobiology of Pain Laboratory, Departamento de Farmacobiología, Cinvestav, Unidad Coapa, Ciudad de México, Mexico
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46
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Stumpff F. A look at the smelly side of physiology: transport of short chain fatty acids. Pflugers Arch 2018; 470:571-598. [PMID: 29305650 DOI: 10.1007/s00424-017-2105-9] [Citation(s) in RCA: 92] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Revised: 12/19/2017] [Accepted: 12/20/2017] [Indexed: 12/14/2022]
Abstract
Fermentative organs such as the caecum, the colon, and the rumen have evolved to produce and absorb energy rich short chain fatty acids (SCFA) from otherwise indigestible substrates. Classical models postulate diffusional uptake of the undissociated acid (HSCFA). However, in net terms, a major part of SCFA absorption occurs with uptake of Na+ and resembles classical, coupled electroneutral NaCl transport. Considerable evidence suggests that the anion transporting proteins expressed by epithelia of fermentative organs are poorly selective and that their main function may be to transport acetate-, propionate-, butyrate- and HCO3- as the physiologically relevant anions. Apical uptake of SCFA thus involves non-saturable diffusion of the undissociated acid (HSCFA), SCFA-/HCO3- exchange via DRA (SLC26A3) and/or SCFA--H+ symport (MCT1, SLC16A1). All mechanisms lead to cytosolic acidification with stimulation of Na+/H+ exchange via NHE (SLC9A2/3). Basolaterally, Na+ leaves via the Na+/K+-ATPase with recirculation of K+. Na+ efflux drives the transport of SCFA- anions through volume-regulated anion channels, such as maxi-anion channels (possibly SLCO2A1), LRRC8, anoctamins, or uncoupled exchangers. When luminal buffering is inadequate, basolateral efflux will increasingly involve SCFA-/ HCO3- exchange (AE1/2, SCL4A1/2), or efflux of SCFA- with H+ (MCT1/4, SLC16A1/3). Furthermore, protons can be basolaterally removed by NHE1 (SCL9A1) or NBCe1 (SLC4A4). The purpose of these transport proteins is to maximize the amount of SCFA transported from the tightly buffered ingesta while minimizing acid transport through the epithelium. As known from the rumen for many decades, a disturbance of these processes is likely to cause severe colonic disease.
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Affiliation(s)
- Friederike Stumpff
- Institute of Veterinary Physiology, Department of Veterinary Medicine, Freie Universität Berlin, Oertzenweg 19b, 14163, Berlin, Germany.
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47
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Andolfo I, Russo R, Gambale A, Iolascon A. Hereditary stomatocytosis: An underdiagnosed condition. Am J Hematol 2018; 93:107-121. [PMID: 28971506 DOI: 10.1002/ajh.24929] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Revised: 09/26/2017] [Accepted: 09/27/2017] [Indexed: 12/11/2022]
Abstract
Hereditary stomatocytoses are a wide class of hemolytic anemias characterized by alterations of ionic flux with increased cation permeability that results in inappropriate shrinkage or swelling of the erythrocytes, and water lost or gained osmotically. The last few years have been crucial for new acquisitions in this field in terms of identifying new causative genes and of studying their pathogenetic mechanisms. This review summarizes the main features of erythrocyte membrane transport diseases, dividing them into forms with either isolated erythroid phenotype (nonsyndromic) or extra-hematological manifestations (syndromic), and focusing particularly on the most recent advances regarding dehydrated forms of hereditary stomatocytosis and familial pseudohyperkalemia.
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Affiliation(s)
- Immacolata Andolfo
- Dipartimento di Medicina Molecolare e Biotecnologie Mediche, Università degli Studi di Napoli Federico II; Napoli Italy
- CEINGE Biotecnologie Avanzate; Napoli Italy
| | - Roberta Russo
- Dipartimento di Medicina Molecolare e Biotecnologie Mediche, Università degli Studi di Napoli Federico II; Napoli Italy
- CEINGE Biotecnologie Avanzate; Napoli Italy
| | - Antonella Gambale
- Dipartimento di Medicina Molecolare e Biotecnologie Mediche, Università degli Studi di Napoli Federico II; Napoli Italy
- CEINGE Biotecnologie Avanzate; Napoli Italy
| | - Achille Iolascon
- Dipartimento di Medicina Molecolare e Biotecnologie Mediche, Università degli Studi di Napoli Federico II; Napoli Italy
- CEINGE Biotecnologie Avanzate; Napoli Italy
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48
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Celay J, Lozano T, Concepcion AR, Beltrán E, Rudilla F, García-Barchino MJ, Robles EF, Rabal O, de Miguel I, Panizo C, Casares N, Oyarzabal J, Prieto J, Medina JF, Lasarte JJ, Martínez-Climent JÁ. Targeting the anion exchanger 2 with specific peptides as a new therapeutic approach in B lymphoid neoplasms. Haematologica 2017; 103:1065-1072. [PMID: 29191842 PMCID: PMC6058773 DOI: 10.3324/haematol.2017.175687] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Accepted: 11/24/2017] [Indexed: 12/20/2022] Open
Abstract
Regulatory T (Treg) cells can weaken antitumor immune responses, and inhibition of their function appears to be a promising therapeutic approach in cancer patients. Mice with targeted deletion of the gene encoding the Cl-/HCO3- anion exchanger AE2 (also termed SLC4A2), a membrane-bound carrier involved in intracellular pH regulation, showed a progressive decrease in the number of Treg cells. We therefore challenged AE2 as a potential target for tumor therapy, and generated linear peptides designed to bind the third extracellular loop of AE2, which is crucial for its exchange activity. Peptide p17AE2 exhibited optimal interaction ability and indeed promoted apoptosis in mouse and human Treg cells, while activating effector T-cell function. Interestingly, this linear peptide also induced apoptosis in different types of human leukemia, lymphoma and multiple myeloma cell lines and primary malignant samples, while it showed only moderate effects on normal B lymphocytes. Finally, a macrocyclic AE2 targeting peptide exhibiting increased stability in vivo was effective in mice xenografted with B-cell lymphoma. These data suggest that targeting the anion exchanger AE2 with specific peptides may represent an effective therapeutic approach in B-cell malignancies.
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Affiliation(s)
- Jon Celay
- Division of Hematological-Oncology, Center for Applied Medical Research (CIMA), University of Navarra, CIBERONC, IDISNA, Pamplona, Spain
| | - Teresa Lozano
- Program of Immunology and Immunotherapy, Center for Applied Medical Research (CIMA), University of Navarra, Pamplona, Spain
| | - Axel R Concepcion
- Division of Hepatology, Center for Applied Medical Research (CIMA), University of Navarra, Pamplona, Spain.,Department of Pathology, New York University School of Medicine, New York, NY, USA
| | - Elena Beltrán
- Division of Hematological-Oncology, Center for Applied Medical Research (CIMA), University of Navarra, CIBERONC, IDISNA, Pamplona, Spain.,Department of Pharmacology, University of Navarra, Pamplona, Spain
| | - Francesc Rudilla
- Program of Immunology and Immunotherapy, Center for Applied Medical Research (CIMA), University of Navarra, Pamplona, Spain
| | - María José García-Barchino
- Division of Hematological-Oncology, Center for Applied Medical Research (CIMA), University of Navarra, CIBERONC, IDISNA, Pamplona, Spain
| | - Eloy F Robles
- Division of Hematological-Oncology, Center for Applied Medical Research (CIMA), University of Navarra, CIBERONC, IDISNA, Pamplona, Spain
| | - Obdulia Rabal
- Small Molecule Discovery Platform and Molecular Therapeutics Program, Center for Applied Medical Research (CIMA), University of Navarra, Pamplona, Spain
| | - Irene de Miguel
- Small Molecule Discovery Platform and Molecular Therapeutics Program, Center for Applied Medical Research (CIMA), University of Navarra, Pamplona, Spain
| | - Carlos Panizo
- Department of Hematology, Clinica Universidad de Navarra, Pamplona, Spain
| | - Noelia Casares
- Program of Immunology and Immunotherapy, Center for Applied Medical Research (CIMA), University of Navarra, Pamplona, Spain
| | - Julen Oyarzabal
- Small Molecule Discovery Platform and Molecular Therapeutics Program, Center for Applied Medical Research (CIMA), University of Navarra, Pamplona, Spain
| | - Jesús Prieto
- Program of Immunology and Immunotherapy, Center for Applied Medical Research (CIMA), University of Navarra, Pamplona, Spain.,Division of Hepatology, Center for Applied Medical Research (CIMA), University of Navarra, Pamplona, Spain
| | - Juan F Medina
- Division of Hepatology, Center for Applied Medical Research (CIMA), University of Navarra, Pamplona, Spain
| | - Juan José Lasarte
- Program of Immunology and Immunotherapy, Center for Applied Medical Research (CIMA), University of Navarra, Pamplona, Spain
| | - José Ángel Martínez-Climent
- Division of Hematological-Oncology, Center for Applied Medical Research (CIMA), University of Navarra, CIBERONC, IDISNA, Pamplona, Spain
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49
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Saravanaperumal SA, Gibbons SJ, Malysz J, Sha L, Linden DR, Szurszewski JH, Farrugia G. Extracellular Cl - regulates electrical slow waves and setting of smooth muscle membrane potential by interstitial cells of Cajal in mouse jejunum. Exp Physiol 2017; 103:40-57. [PMID: 28971566 DOI: 10.1113/ep086367] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Accepted: 09/27/2017] [Indexed: 12/12/2022]
Abstract
NEW FINDINGS What is the central question of this study? The aim was to investigate the roles of extracellular chloride in electrical slow waves and resting membrane potential of mouse jejunal smooth muscle by replacing chloride with the impermeant anions gluconate and isethionate. What is the main finding and its importance? The main finding was that in smooth muscle cells, the resting Cl- conductance is low, whereas transmembrane Cl- movement in interstitial cells of Cajal (ICCs) is a major contributor to the shape of electrical slow waves. Furthermore, the data confirm that ICCs set the smooth muscle membrane potential and that altering Cl- homeostasis in ICCs can alter the smooth muscle membrane potential. Intracellular Cl- homeostasis is regulated by anion-permeable channels and transporters and contributes to excitability of many cell types, including smooth muscle and interstitial cells of Cajal (ICCs). Our aims were to investigate the effects on electrical activity in mouse jejunal muscle strips of replacing extracellular Cl- (Cl-o ) with the impermeant anions gluconate and isethionate. On reducing Cl-o , effects were observed on electrical slow waves, with small effects on smooth muscle membrane voltage (Em ). Restoration of Cl- hyperpolarized smooth muscle Em proportional to the change in Cl-o concentration. Replacement of 90% of Cl-o with gluconate reversibly abolished slow waves in five of nine preparations. Slow waves were maintained in isethionate. Gluconate and isethionate substitution had similar concentration-dependent effects on peak amplitude, frequency, width at half peak amplitude, rise time and decay time of residual slow waves. Gluconate reduced free ionized Ca2+ in Krebs solutions to 0.13 mm. In Krebs solutions containing normal Cl- and 0.13 mm free Ca2+ , slow wave frequency was lower, width at half peak amplitude was smaller, and decay time was faster. The transient hyperpolarization following restoration of Cl-o was not observed in W/Wv mice, which lack pacemaker ICCs in the small intestine. We conclude that in smooth muscle cells, the resting Cl- conductance is low, whereas transmembrane Cl- movement in ICCs plays a major role in generation or propagation of slow waves. Furthermore, these data support a role for ICCs in setting smooth muscle Em and that altering Cl- homeostasis in ICCs can alter smooth muscle Em .
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Affiliation(s)
| | - Simon J Gibbons
- Enteric NeuroScience Program, Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, MN, USA
| | - John Malysz
- Enteric NeuroScience Program, Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, MN, USA
| | - Lei Sha
- Enteric NeuroScience Program, Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, MN, USA
| | - David R Linden
- Enteric NeuroScience Program, Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, MN, USA
| | - Joseph H Szurszewski
- Enteric NeuroScience Program, Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, MN, USA
| | - Gianrico Farrugia
- Enteric NeuroScience Program, Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, MN, USA
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50
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Besouw MTP, Bienias M, Walsh P, Kleta R, Van't Hoff WG, Ashton E, Jenkins L, Bockenhauer D. Clinical and molecular aspects of distal renal tubular acidosis in children. Pediatr Nephrol 2017; 32:987-996. [PMID: 28188436 DOI: 10.1007/s00467-016-3573-4] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Revised: 12/16/2016] [Accepted: 12/19/2016] [Indexed: 11/30/2022]
Abstract
BACKGROUND Distal renal tubular acidosis (dRTA) is characterized by hyperchloraemic metabolic acidosis, hypokalaemia, hypercalciuria and nephrocalcinosis. It is due to reduced urinary acidification by the α-intercalated cells in the collecting duct and can be caused by mutations in genes that encode subunits of the vacuolar H+-ATPase (ATP6V1B1, ATP6V0A4) or the anion exchanger 1 (SLC4A1). Treatment with alkali is the mainstay of therapy. METHODS This study is an analysis of clinical data from a long-term follow-up of 24 children with dRTA in a single centre, including a genetic analysis. RESULTS Of the 24 children included in the study, genetic diagnosis was confirmed in 19 patients, with six children having mutations in ATP6V1B1, ten in ATP6V0A4 and three in SLC4A1; molecular diagnosis was not available for five children. Five novel mutations were detected (2 in ATP6V1B1 and 3 in ATP6V0A4). Two-thirds of patients presented with features of proximal tubular dysfunction leading to an erroneous diagnosis of renal Fanconi syndrome. The proximal tubulopathy disappeared after resolution of acidosis, indicating the importance of following proximal tubular function to establish the correct diagnosis. Growth retardation with a height below -2 standard deviation score was found in ten patients at presentation, but persisted in only three of these children once established on alkali treatment. Sensorineural hearing loss was found in five of the six patients with an ATP6V1B1 mutation. Only one patient with an ATP6V0A4 mutation had sensorineural hearing loss during childhood. Nine children developed medullary cysts, but without apparent clinical consequences. Cyst development in this cohort was not correlated with age at therapy onset, molecular diagnosis, growth parameters or renal function. CONCLUSION In general, the prognosis of dRTA is good in children treated with alkali.
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Affiliation(s)
- Martine T P Besouw
- Department of Pediatric Nephrology, Great Ormond Street Hospital for Children NHS Foundation Trust, Great Ormond Street, London, WC1N 3JH, UK
| | - Marc Bienias
- Department of Pediatrics, Medical Faculty Carl Gustav Carus, Technical University Dresden, Dresden, Germany
| | - Patrick Walsh
- Great North Children's Hospital, Newcastle upon Tyne NHS Foundation Trust, Newcastle, UK
| | - Robert Kleta
- Department of Pediatric Nephrology, Great Ormond Street Hospital for Children NHS Foundation Trust, Great Ormond Street, London, WC1N 3JH, UK.,Centre for Nephrology, University College London Institute of Child Health, London, UK
| | - William G Van't Hoff
- Department of Pediatric Nephrology, Great Ormond Street Hospital for Children NHS Foundation Trust, Great Ormond Street, London, WC1N 3JH, UK
| | - Emma Ashton
- North East Thames Regional Genetics Service Laboratories, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
| | - Lucy Jenkins
- North East Thames Regional Genetics Service Laboratories, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
| | - Detlef Bockenhauer
- Department of Pediatric Nephrology, Great Ormond Street Hospital for Children NHS Foundation Trust, Great Ormond Street, London, WC1N 3JH, UK. .,Centre for Nephrology, University College London Institute of Child Health, London, UK.
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