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Su S, Wahl A, Rugis J, Suresh V, Yule DI, Sneyd J. A mathematical model of ENaC and Slc26a6 regulation by CFTR in salivary gland ducts. Am J Physiol Gastrointest Liver Physiol 2024; 326:G555-G566. [PMID: 38349781 DOI: 10.1152/ajpgi.00168.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Revised: 01/17/2024] [Accepted: 02/06/2024] [Indexed: 02/15/2024]
Abstract
Cystic fibrosis (CF) is a genetic disease caused by the mutations of cystic fibrosis transmembrane conductance regulator (CFTR), the cystic fibrosis transmembrane conductance regulator gene. Cftr is a critical ion channel expressed in the apical membrane of mouse salivary gland striated duct cells. Although Cftr is primarily a Cl- channel, its knockout leads to higher salivary Cl- and Na+ concentrations and lower pH. Mouse experiments show that the activation of Cftr upregulates epithelial Na+ channel (ENaC) protein expression level and Slc26a6 (a 1Cl-:2[Formula: see text] exchanger of the solute carrier family) activity. Experimentally, it is difficult to predict how much the coregulation effects of CFTR contribute to the abnormal Na+, Cl-, and [Formula: see text] concentrations and pH in CF saliva. To address this question, we construct a wild-type mouse salivary gland model and simulate CFTR knockout by altering the expression levels of CFTR, ENaC, and Slc26a6. By reproducing the in vivo and ex vivo final saliva measurements from wild-type and CFTR knockout animals, we obtain computational evidence that ENaC and Slc26a6 activities are downregulated in CFTR knockout in salivary glands.NEW & NOTEWORTHY This paper describes a salivary gland mathematical model simulating the ion exchange between saliva and the salivary gland duct epithelium. The novelty lies in the implementation of CFTR regulating ENaC and Slc26a6 in a CFTR knockout gland. By reproducing the experimental saliva measurements in wild-type and CFTR knockout glands, the model shows that CFTR regulates ENaC and Slc26a6 anion exchanger in salivary glands. The method could be used to understand the various cystic fibrosis phenotypes.
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Affiliation(s)
- Shan Su
- Department of Mathematics, University of Auckland, Auckland, New Zealand
| | - Amanda Wahl
- Department of Pharmacology and Physiology, University of Rochester, Rochester, New York, United States
| | - John Rugis
- Department of Mathematics, University of Auckland, Auckland, New Zealand
| | - Vinod Suresh
- Auckland Biomedical Engineering Institute, University of Auckland, Auckland, New Zealand
- Department of Engineering Science, University of Auckland, Auckland, New Zealand
| | - David I Yule
- Department of Pharmacology and Physiology, University of Rochester, Rochester, New York, United States
| | - James Sneyd
- Department of Mathematics, University of Auckland, Auckland, New Zealand
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Qiao Y, Qiao L, Zhao P, Zhang P, Wu F, Zhang J, Gao L, Liu B, Zhang L. Phosphoprotein Detection in Sweat Realized by Intercalation Structure 2D@3D g-C 3N 4@Fe 3O 4 Wearable Sensitive Motif. BIOSENSORS 2022; 12:bios12060361. [PMID: 35735509 PMCID: PMC9220892 DOI: 10.3390/bios12060361] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2022] [Revised: 05/19/2022] [Accepted: 05/20/2022] [Indexed: 05/03/2023]
Abstract
Abnormal protein phosphorylation in sweat metabolites is closely related to cancer, cardiovascular disease, and other diseases. The real-time monitoring of phosphoproteins in sweat is significant for early monitoring of disease biomarkers. Here, a high-efficiency electrochemical sensor for phosphoprotein in sweat was realized by 2D@3D g-C3N4@Fe3O4 with intercalation structure. Common phosphoprotein β-Casein was selected to demonstrate the platform's functionalities. The detection limit of g-C3N4@Fe3O4 could be as low as 9.7 μM, and the detection range was from 0.01 mg/mL to 1 mg/mL. In addition, the sensing platform showed good selectivity, reproducibility, and stability. We also investigated the effects of interface structure on adsorption properties and electronic properties of the g-C3N4 and Fe3O4 heterostructure using DFT. More electrons from Fe3O4 were transferred to g-C3N4, which increased the electrons in the energy band of N atoms and promoted the formation of stable N-H bonds with H atoms in phosphoproteins. We demonstrated phosphoprotein sensor functionality by measuring the phosphoprotein in human sweat during exercising. This work realizes a sensing platform for noninvasive and continuous detection of sweat phosphoproteins in wearable devices.
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Affiliation(s)
- Yuting Qiao
- School of Mechanical Engineering, Qinghai University, Xining 810016, China; (Y.Q.); (P.Z.); (P.Z.); (F.W.); (J.Z.)
| | - Lijuan Qiao
- Research Center of Basic Medical Science, Medical College, Qinghai University, Xining 810016, China
- Correspondence: (L.Q.); (L.G.); (B.L.); Fax: +86-97-1531-0440 (B.L.)
| | - Peize Zhao
- School of Mechanical Engineering, Qinghai University, Xining 810016, China; (Y.Q.); (P.Z.); (P.Z.); (F.W.); (J.Z.)
| | - Peng Zhang
- School of Mechanical Engineering, Qinghai University, Xining 810016, China; (Y.Q.); (P.Z.); (P.Z.); (F.W.); (J.Z.)
| | - Fanbin Wu
- School of Mechanical Engineering, Qinghai University, Xining 810016, China; (Y.Q.); (P.Z.); (P.Z.); (F.W.); (J.Z.)
| | - Jiahui Zhang
- School of Mechanical Engineering, Qinghai University, Xining 810016, China; (Y.Q.); (P.Z.); (P.Z.); (F.W.); (J.Z.)
| | - Li Gao
- School of Mechanical Engineering, Qinghai University, Xining 810016, China; (Y.Q.); (P.Z.); (P.Z.); (F.W.); (J.Z.)
- Correspondence: (L.Q.); (L.G.); (B.L.); Fax: +86-97-1531-0440 (B.L.)
| | - Bingxin Liu
- School of Mechanical Engineering, Qinghai University, Xining 810016, China; (Y.Q.); (P.Z.); (P.Z.); (F.W.); (J.Z.)
- Correspondence: (L.Q.); (L.G.); (B.L.); Fax: +86-97-1531-0440 (B.L.)
| | - Lei Zhang
- Department of Mechanical Engineering, University of Alaska Fairbanks, P.O. Box 755905, Fairbanks, AK 99775-5905, USA;
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Palma AG, Kotsias BA. The Effect of Dynasore Upon the Negative Interaction Between ENaC and CFTR Channels in Xenopus laevis Oocytes. J Membr Biol 2022; 255:61-69. [DOI: 10.1007/s00232-021-00212-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2021] [Accepted: 12/22/2021] [Indexed: 11/29/2022]
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Li AQ, Sun ZP, Liu X, Yang JS, Jin F, Zhu L, Jia WH, De Vos S, Van Stappen G, Bossier P, Yang WJ. The chloride channel cystic fibrosis transmembrane conductance regulator (CFTR) controls cellular quiescence by hyperpolarizing the cell membrane during diapause in the crustacean Artemia. J Biol Chem 2019; 294:6598-6611. [PMID: 30765604 DOI: 10.1074/jbc.ra118.005900] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Revised: 02/10/2019] [Indexed: 01/10/2023] Open
Abstract
Cellular quiescence, a reversible state in which growth, proliferation, and other cellular activities are arrested, is important for self-renewal, differentiation, development, regeneration, and stress resistance. However, the physiological mechanisms underlying cellular quiescence remain largely unknown. In the present study, we used embryos of the crustacean Artemia in the diapause stage, in which these embryos remain quiescent for prolonged periods, as a model to explore the relationship between cell-membrane potential (V mem) and quiescence. We found that V mem is hyperpolarized and that the intracellular chloride concentration is high in diapause embryos, whereas V mem is depolarized and intracellular chloride concentration is reduced in postdiapause embryos and during further embryonic development. We identified and characterized the chloride ion channel protein cystic fibrosis transmembrane conductance regulator (CFTR) of Artemia (Ar-CFTR) and found that its expression is silenced in quiescent cells of Artemia diapause embryos but remains constant in all other embryonic stages. Ar-CFTR knockdown and GlyH-101-mediated chemical inhibition of Ar-CFTR produced diapause embryos having a high V mem and intracellular chloride concentration, whereas control Artemia embryos released free-swimming nauplius larvae. Transcriptome analysis of embryos at different developmental stages revealed that proliferation, differentiation, and metabolism are suppressed in diapause embryos and restored in postdiapause embryos. Combined with RNA sequencing (RNA-Seq) of GlyH-101-treated MCF-7 breast cancer cells, these analyses revealed that CFTR inhibition down-regulates the Wnt and Aurora Kinase A (AURKA) signaling pathways and up-regulates the p53 signaling pathway. Our findings provide insight into CFTR-mediated regulation of cellular quiescence and V mem in the Artemia model.
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Affiliation(s)
- An-Qi Li
- From the College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Zhan-Peng Sun
- From the College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Xu Liu
- From the College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Jin-Shu Yang
- From the College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Feng Jin
- From the College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Lin Zhu
- From the College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Wen-Huan Jia
- From the College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Stephanie De Vos
- the Laboratory of Aquaculture and Artemia Reference Center, Department of Animal Production, Ghent University, B-9000 Ghent, Belgium, and
| | - Gilbert Van Stappen
- the Laboratory of Aquaculture and Artemia Reference Center, Department of Animal Production, Ghent University, B-9000 Ghent, Belgium, and
| | - Peter Bossier
- the Laboratory of Aquaculture and Artemia Reference Center, Department of Animal Production, Ghent University, B-9000 Ghent, Belgium, and
| | - Wei-Jun Yang
- From the College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China, .,the Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266000, China
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Wilson TE. Renal sympathetic nerve, blood flow, and epithelial transport responses to thermal stress. Auton Neurosci 2016; 204:25-34. [PMID: 28043810 DOI: 10.1016/j.autneu.2016.12.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2016] [Revised: 11/28/2016] [Accepted: 12/20/2016] [Indexed: 12/12/2022]
Abstract
Thermal stress is a profound sympathetic stress in humans; kidney responses involve altered renal sympathetic nerve activity (RSNA), renal blood flow, and renal epithelial transport. During mild cold stress, RSNA spectral power but not total activity is altered, renal blood flow is maintained or decreased, and epithelial transport is altered consistent with a sympathetic stress coupled with central volume loaded state. Hypothermia decreases RSNA, renal blood flow, and epithelial transport. During mild heat stress, RSNA is increased, renal blood flow is decreased, and epithelial transport is increased consistent with a sympathetic stress coupled with a central volume unloaded state. Hyperthermia extends these directional changes, until heat illness results. Because kidney responses are very difficult to study in humans in vivo, this review describes and qualitatively evaluates an in vivo human skin model of sympathetically regulated epithelial tissue compared to that of the nephron. This model utilizes skin responses to thermal stress, involving 1) increased skin sympathetic nerve activity (SSNA), decreased skin blood flow, and suppressed eccrine epithelial transport during cold stress; and 2) increased SSNA, skin blood flow, and eccrine epithelial transport during heat stress. This model appears to mimic aspects of the renal responses. Investigations of skin responses, which parallel certain renal responses, may aid understanding of epithelial-sympathetic nervous system interactions during cold and heat stress.
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Affiliation(s)
- Thad E Wilson
- Division of Biomedical Sciences, Marian University College of Osteopathic Medicine, Indianapolis, IN, USA.
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Concepcion AR, Feske S. Regulation of epithelial ion transport in exocrine glands by store-operated Ca 2+ entry. Cell Calcium 2016; 63:53-59. [PMID: 28027799 DOI: 10.1016/j.ceca.2016.12.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Accepted: 12/17/2016] [Indexed: 02/08/2023]
Abstract
Store-operated Ca2+ entry (SOCE) is a conserved mechanism of Ca2+ influx that regulates Ca2+ signaling in many cell types. SOCE is activated by depletion of endoplasmic reticulum (ER) Ca2+ stores in response to physiological agonist stimulation. After it was first postulated by J.W. Putney Jr. in 1986, SOCE has been described in a large number of non-excitable cell types including secretory cells of different exocrine glands. Here we discuss the mechanisms by which SOCE controls salt and fluid secretion in exocrine glands, with a special focus on eccrine sweat glands. In sweat glands, SOCE plays an important, non-redundant role in regulating the function of Ca2+-activated Cl- channels (CaCC), Cl- secretion and sweat production. In the absence of key regulators of SOCE such as the CRAC channel pore subunit ORAI1 and its activator STIM1, the Ca2+-activated chloride channel TMEM16A is inactive and fails to secrete Cl-, resulting in anhidrosis in mice and human patients.
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Affiliation(s)
- Axel R Concepcion
- Department of Pathology, New York University School of Medicine, New York, NY, 10016, USA
| | - Stefan Feske
- Department of Pathology, New York University School of Medicine, New York, NY, 10016, USA.
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Downs CA, Kreiner LH, Johnson NM, Brown LA, Helms MN. Receptor for advanced glycation end-products regulates lung fluid balance via protein kinase C-gp91(phox) signaling to epithelial sodium channels. Am J Respir Cell Mol Biol 2015; 52:75-87. [PMID: 24978055 DOI: 10.1165/rcmb.2014-0002oc] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The receptor for advanced glycation end-products (RAGE), a multiligand member of the Ig family, may play a crucial role in the regulation of lung fluid balance. We quantified soluble RAGE (sRAGE), a decoy isoform, and advanced glycation end-products (AGEs) from the bronchoalveolar lavage fluid of smokers and nonsmokers, and tested the hypothesis that AGEs regulate lung fluid balance through protein kinase C (PKC)-gp91(phox) signaling to the epithelial sodium channel (ENaC). Human bronchoalveolar lavage samples from smokers showed increased AGEs (9.02 ± 3.03 μg versus 2.48 ± 0.53 μg), lower sRAGE (1,205 ± 292 pg/ml versus 1,910 ± 263 pg/ml), and lower volume(s) of epithelial lining fluid (97 ± 14 ml versus 133 ± 17 ml). sRAGE levels did not predict ELF volumes in nonsmokers; however, in smokers, higher volumes of ELF were predicted with higher levels of sRAGE. Single-channel patch clamp analysis of rat alveolar epithelial type 1 cells showed that AGEs increased ENaC activity measured as the product of the number of channels (N) and the open probability (Po) (NPo) from 0.19 ± 0.08 to 0.83 ± 0.22 (P = 0.017) and the subsequent addition of 4-hydroxy-2, 2, 6, 6-tetramethylpiperidine-N-oxyl decreased ENaC NPo to 0.15 ± 0.07 (P = 0.01). In type 2 cells, human AGEs increased ENaC NPo from 0.12 ± 0.05 to 0.53 ± 0.16 (P = 0.025) and the addition of 4-hydroxy-2, 2, 6, 6-tetramethylpiperidine-N-oxyl decreased ENaC NPo to 0.10 ± 0.03 (P = 0.013). Using molecular and biochemical techniques, we observed that inhibition of RAGE and PKC activity attenuated AGE-induced activation of ENaC. AGEs induced phosphorylation of p47(phox) and increased gp91(phox)-dependent reactive oxygen species production, a response that was abrogated with RAGE or PKC inhibition. Finally, tracheal instillation of AGEs promoted clearance of lung fluid, whereas concomitant inhibition of RAGE, PKC, and gp91(phox) abrogated the response.
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Exercise intolerance, malnutrition, abnormal sweat chloride levels, and two CFTR mutations: is it cystic fibrosis? J Pediatr Health Care 2015; 29:201-4. [PMID: 25060775 DOI: 10.1016/j.pedhc.2014.05.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/26/2014] [Revised: 05/24/2014] [Accepted: 05/31/2014] [Indexed: 11/21/2022]
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Murota H, Matsui S, Ono E, Kijima A, Kikuta J, Ishii M, Katayama I. Sweat, the driving force behind normal skin: an emerging perspective on functional biology and regulatory mechanisms. J Dermatol Sci 2014; 77:3-10. [PMID: 25266651 DOI: 10.1016/j.jdermsci.2014.08.011] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2014] [Revised: 08/22/2014] [Accepted: 08/27/2014] [Indexed: 11/19/2022]
Abstract
The various symptoms associated with excessive or insufficient perspiration can significantly reduce a patient's quality of life. If a versatile and minimally invasive method could be established for returning sweat activity to normalcy, there is no question that it could be used in the treatment of many diseases that are believed to involve perspiration. For this reason, based on an understanding of the sweat-gland control function and sweat activity, it was necessary to conduct a comprehensive search for the factors that control sweating, such as the central and peripheral nerves that control sweat-gland function, the microenvironment surrounding the sweat glands, and lifestyle. We focused on the mechanism by which atopic dermatitis leads to hypohidrosis and confirmed that histamine inhibits acetylcholinergic sweating. Acetylcholine promotes the phosphorylation of glycogen synthesis kinase 3β (GSK3β) in the sweat-gland secretory cells and leads to sensible perspiration. By suppressing the phosphorylation of GSK3β, histamine inhibits the movement of sweat from the sweat-gland secretory cells through the sweat ducts, which could presumably be demonstrated by dynamic observations of the sweat glands using two-photon microscopy. It is expected that the discovery of new factors that control sweat-gland function can contribute to the treatment of diseases associated with dyshidrosis.
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Affiliation(s)
- Hiroyuki Murota
- Department of Dermatology, Course of Integrated Medicine, Graduate School of Medicine, Osaka University, 2-2 Yamadaoka, Suita, Osaka, Japan.
| | - Saki Matsui
- Department of Dermatology, Course of Integrated Medicine, Graduate School of Medicine, Osaka University, 2-2 Yamadaoka, Suita, Osaka, Japan
| | - Emi Ono
- Department of Dermatology, Course of Integrated Medicine, Graduate School of Medicine, Osaka University, 2-2 Yamadaoka, Suita, Osaka, Japan
| | - Akiko Kijima
- Department of Dermatology, Course of Integrated Medicine, Graduate School of Medicine, Osaka University, 2-2 Yamadaoka, Suita, Osaka, Japan
| | - Junichi Kikuta
- Department of Immunology and Cell Biology, Graduate School of Medicine and Frontier Bioscience, Osaka University, 2-2 Yamadaoka, Suita, Osaka, Japan
| | - Masaru Ishii
- Department of Immunology and Cell Biology, Graduate School of Medicine and Frontier Bioscience, Osaka University, 2-2 Yamadaoka, Suita, Osaka, Japan
| | - Ichiro Katayama
- Department of Dermatology, Course of Integrated Medicine, Graduate School of Medicine, Osaka University, 2-2 Yamadaoka, Suita, Osaka, Japan
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Varelogianni G, Hussain R, Strid H, Oliynyk I, Roomans GM, Johannesson M. The effect of ambroxol on chloride transport, CFTR and ENaC in cystic fibrosis airway epithelial cells. Cell Biol Int 2013; 37:1149-56. [DOI: 10.1002/cbin.10146] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2013] [Accepted: 05/24/2013] [Indexed: 11/10/2022]
Affiliation(s)
- Georgia Varelogianni
- School of Medicine, Örebro University; University Hospital, Clinical Research Centre; SE-70185; Örebro; Sweden
| | - Rashida Hussain
- School of Medicine, Örebro University; University Hospital, Clinical Research Centre; SE-70185; Örebro; Sweden
| | - Hilja Strid
- School of Medicine, Örebro University; University Hospital, Clinical Research Centre; SE-70185; Örebro; Sweden
| | - Igor Oliynyk
- School of Medicine, Örebro University; University Hospital, Clinical Research Centre; SE-70185; Örebro; Sweden
| | - Godfried M. Roomans
- School of Medicine, Örebro University; University Hospital, Clinical Research Centre; SE-70185; Örebro; Sweden
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11
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O'Grady SM. Reply from Scott M. O’Grady. J Physiol 2011. [DOI: 10.1113/jphysiol.2011.218941] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
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Reddy MM, Wang XF, Quinton PM. Effect of cytosolic pH on epithelial Na+ channel in normal and cystic fibrosis sweat ducts. J Membr Biol 2008; 225:1-11. [PMID: 18937003 DOI: 10.1007/s00232-008-9126-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2008] [Accepted: 08/25/2008] [Indexed: 11/24/2022]
Abstract
The activities of cystic fibrosis transmembrane conductance regulator (CFTR) Cl(-) channel and the amiloride-sensitive epithelial Na(+) channel (ENaC) are acutely coordinated in the sweat duct. However, the mechanisms responsible for cross-talk between these ion channels are unknown. Previous studies indicated that luminal pH of sweat ducts varies over 3 pH units and that the cytoplasmic pH affects both CFTR and ENaC. Therefore, using basolaterally alpha-toxin-permeabilized apical membrane preparations of sweat ducts as an experimental system, we tested the hypothesis that the cytosolic pH may mediate the cross-talk between CFTR and ENaC. We showed that while luminal pH had no effect, cytosolic pH acutely affected ENaC activity. That is, acidic pH inhibited, while basic pH activated, ENaC. pH regulation of ENaC appears to be independent of CFTR or endogenous kinase activities because basic pH independently stimulated ENaC (1) in normal ducts even when CFTR was deactivated, (2) in CF ducts that lack CFTR in the plasma membranes and (3) after blocking endogenous kinase activity with staurosporine. Considering the evidence of Na(+)/H(+) exchange (NHE) activity as shown by the expression of mRNA and function of NHE in the basolateral membrane of the sweat duct, we postulate that changes in cytosolic Na(+) ([Na(+)]( i )) may alter cytosolic pH (pH( i )) as salt loads into the cell during electrolyte absorption. These changes may play a role in coordinating the activities of ENaC and CFTR during transepithelial salt transport.
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Affiliation(s)
- M M Reddy
- Department of Pediatrics-0831, School of Medicine, University of California-San Diego, La Jolla, CA 92093-0831, USA.
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Abstract
Lessons from the sweat gland on cystic fibrosis (CF) began long before modern medicine became a science. In European folklore, the curse that “a child that taste salty when kissed will soon die” (Alonso y de los Ruyzes de Fonteca J. Diez Previlegios para Mugeres Prenadas. Henares, Spain, 1606) has been taken by many as a direct reference to cystic fibrosis [Busch R. Acta Univ Carol Med (Praha) 36: 13–15, 1990]. The high salt concentration in sweat from patients with CF is now accepted as almost pathognomonic with this fatal genetic disease, but the earliest descriptions of cystic fibrosis as a disease entity did not mention sweat or sweat glands (Andersen DH. Am J Dis Child 56: 344–399, 1938; Andersen DH, Hodges RG. Am J Dis Child 72: 62–80, 1946). Nonetheless, defective sweating soon became an inseparable, and major, component of the constellation of symptoms that diagnose “cystic fibrosis” (Davis PB. Am J Respir Crit Care Med 173: 475–482, 2006). The sweat gland has played a foremost role in diagnosing, defining pathophysiology, debunking misconceptions, and increasing our understanding of the effects of the disease on organs, tissues, cells, and molecules. The sweat gland has taught us much.
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Affiliation(s)
- Paul M Quinton
- Biomedical Sciences, University of California, Riverside, USA.
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Lu C, Jiang C, Pribanic S, Rotin D. CFTR stabilizes ENaC at the plasma membrane. J Cyst Fibros 2007; 6:419-22. [PMID: 17434346 DOI: 10.1016/j.jcf.2007.03.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2006] [Revised: 02/08/2007] [Accepted: 03/05/2007] [Indexed: 11/20/2022]
Abstract
CFTR was reported to regulate ENaC channel opening, decreasing ENaC activity in airways and increasing it in sweat ducts. We generated MDCK-I cell lines stably expressing tagged alphabetagammaENaC+CFTR or ENaC alone, and developed an assay to quantify cell-surface half-life of ENaC. Surprisingly, we found that co-expressed CFTR stabilizes ENaC at the plasma membrane, suggesting that CFTR regulates ENaC stability, not just opening.
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Affiliation(s)
- C Lu
- Program in Cell Biology, The Hospital for Sick Children, and Biochemistry Department, University of Toronto, 555 University Ave, Toronto, Ontario, Canada M5G 1X8
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