1
|
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] [What about the content of this article? (0)] [Affiliation(s)] [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.
Collapse
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
| |
Collapse
|
2
|
Sure F, Einsiedel J, Gmeiner P, Duchstein P, Zahn D, Korbmacher C, Ilyaskin AV. The small molecule activator S3969 stimulates the epithelial sodium channel by interacting with a specific binding pocket in the channel's β-subunit. J Biol Chem 2024; 300:105785. [PMID: 38401845 DOI: 10.1016/j.jbc.2024.105785] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Revised: 01/13/2024] [Accepted: 02/19/2024] [Indexed: 02/26/2024] Open
Abstract
The epithelial sodium channel (ENaC) is essential for mediating sodium absorption in several epithelia. Its impaired function leads to severe disorders, including pseudohypoaldosteronism type 1 and respiratory distress. Therefore, pharmacological ENaC activators have potential therapeutic implications. Previously, a small molecule ENaC activator (S3969) was developed. So far, little is known about molecular mechanisms involved in S3969-mediated ENaC stimulation. Here, we identified an S3969-binding site in human ENaC by combining structure-based simulations with molecular biological methods and electrophysiological measurements of ENaC heterologously expressed in Xenopus laevis oocytes. We confirmed a previous observation that the extracellular loop of β-ENaC is essential for ENaC stimulation by S3969. Molecular dynamics simulations predicted critical residues in the thumb domain of β-ENaC (Arg388, Phe391, and Tyr406) that coordinate S3969 within a binding site localized at the β-γ-subunit interface. Importantly, mutating each of these residues reduced (R388H; R388A) or nearly abolished (F391G; Y406A) the S3969-mediated ENaC activation. Molecular dynamics simulations also suggested that S3969-mediated ENaC stimulation involved a movement of the α5 helix of the thumb domain of β-ENaC away from the palm domain of γ-ENaC. Consistent with this, the introduction of two cysteine residues (βR437C - γS298C) to form a disulfide bridge connecting these two domains prevented ENaC stimulation by S3969 unless the disulfide bond was reduced by DTT. Finally, we demonstrated that S3969 stimulated ENaC endogenously expressed in cultured human airway epithelial cells (H441). These new findings may lead to novel (patho-)physiological and therapeutic concepts for disorders associated with altered ENaC function.
Collapse
Affiliation(s)
- Florian Sure
- Institute of Cellular and Molecular Physiology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Jürgen Einsiedel
- Department of Chemistry and Pharmacy, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Peter Gmeiner
- Department of Chemistry and Pharmacy, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Patrick Duchstein
- Theoretical Chemistry/Computer Chemistry Center (CCC), Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Dirk Zahn
- Theoretical Chemistry/Computer Chemistry Center (CCC), Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Christoph Korbmacher
- Institute of Cellular and Molecular Physiology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Alexandr V Ilyaskin
- Institute of Cellular and Molecular Physiology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany.
| |
Collapse
|
3
|
Betzemeier B, Braun C, Sieger P, Heckel A, Linz G, Linehan B, Veser T, Wiedenmayer D, Kley JT. Discovery and development of BI 1265162, an ENaC inhibitor for the treatment of cystic fibrosis. Eur J Med Chem 2024; 265:116038. [PMID: 38157597 DOI: 10.1016/j.ejmech.2023.116038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Revised: 12/01/2023] [Accepted: 12/08/2023] [Indexed: 01/03/2024]
Abstract
Lung selective inhibition of the endothelial sodium channel (ENaC) is a potential mutation agnostic treatment of Cystic Fibrosis (CF). We describe the discovery and development of BI 1265162, the first ENaC inhibitor devoid of the amiloride structural motif that entered clinical trials. The design of BI 1265162 focused on its suitability for inhalation via the Respimat® Soft Mist™ Inhaler and a long duration of action. A convergent and scalable route for the synthesis of BI 1265162 as dihydrogen phosphate salt is presented, that was applied to support clinical trials. A phase 2 study with BI 1265162 did not provide a clear sign of clinical benefit. Whether ENaC inhibition will be able to hold its promise for CF patients remains an open question.
Collapse
Affiliation(s)
- Bodo Betzemeier
- Boehringer Ingelheim Pharma GmbH & Co. KG, Chemical Development Germany, Birkendorfer Straße 65, 88397, Biberach an der Riß, Germany
| | - Clemens Braun
- Boehringer Ingelheim Pharma GmbH & Co. KG, Drug Discovery Sciences Germany, Birkendorfer Straße 65, 88397, Biberach an der Riß, Germany
| | - Peter Sieger
- Boehringer Ingelheim Pharma GmbH & Co. KG, Drug Discovery Sciences Germany, Birkendorfer Straße 65, 88397, Biberach an der Riß, Germany
| | - Armin Heckel
- Boehringer Ingelheim Pharma GmbH & Co. KG, Medicinal Chemistry Germany, Birkendorfer Straße 65, 88397, Biberach an der Riß, Germany
| | - Günter Linz
- Boehringer Ingelheim Pharma GmbH & Co. KG, Chemical Development Germany, Birkendorfer Straße 65, 88397, Biberach an der Riß, Germany
| | - Brian Linehan
- Material & Analytical Sciences, Boehringer-Ingelheim, Ridgefield, 06877, Connecticut, USA
| | - Thomas Veser
- Boehringer Ingelheim Pharma GmbH & Co. KG, Medicinal Chemistry Germany, Birkendorfer Straße 65, 88397, Biberach an der Riß, Germany
| | - Dieter Wiedenmayer
- Boehringer Ingelheim Pharma GmbH & Co. KG, Medicinal Chemistry Germany, Birkendorfer Straße 65, 88397, Biberach an der Riß, Germany
| | - Jörg T Kley
- Boehringer Ingelheim Pharma GmbH & Co. KG, Medicinal Chemistry Germany, Birkendorfer Straße 65, 88397, Biberach an der Riß, Germany.
| |
Collapse
|
4
|
Harvey BJ. Molecular mechanisms of dexamethasone actions in COVID-19: Ion channels and airway surface liquid dynamics. Steroids 2024; 202:109348. [PMID: 38049079 DOI: 10.1016/j.steroids.2023.109348] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 11/23/2023] [Accepted: 11/28/2023] [Indexed: 12/06/2023]
Abstract
The COVID-19 pandemic has been a global health crisis of unprecedented magnitude. In the battle against the SARS-CoV-2 coronavirus, dexamethasone, a widely used corticosteroid with potent anti-inflammatory properties, has emerged as a promising therapy in the fight against severe COVID-19. Dexamethasone is a synthetic glucocorticoid that exerts its therapeutic effects by suppressing the immune system and reducing inflammation. In the context of COVID-19, the severe form of the disease is often characterized by a hyperactive immune response, known as a cytokine storm. Dexamethasone anti-inflammatory properties make it a potent tool in modulating this exaggerated immune response. Lung inflammation may lead to excessive fluid accumulation in the airways which can reduce gas exchange and mucociliary clearance. Pulmonary oedema and flooding of the airways are hallmarks of severe COVID-19 lung disease. The volume of airway surface liquid is determined by a delicate balance of salt and water secretion and absorption across the airway epithelium. In addition to its anti-inflammatory actions, dexamethasone modulates the activity of ion channels which regulate electrolyte and water transport across the airway epithelium. The observations of dexamethasone activation of sodium ion absorption via ENaC Na+ channels and inhibition of chloride ion secretion via CFTR Cl- channels to decrease airway surface liquid volume indicate a novel therapeutic action of the glucocorticoid to reverse airway flooding. This brief review delves into the early non-genomic and late genomic signaling mechanisms of dexamethasone regulation of ion channels and airway surface liquid dynamics, shedding light on the molecular mechanisms underpinning the action of the glucocorticoid in managing COVID-19.
Collapse
Affiliation(s)
- Brian J Harvey
- Faculty of Medicine, Royal College of Surgeons in Ireland, RCSI University of Medicine and Health Sciences, Dublin 2, Ireland; Centro de Estudios Cientificos, Valdivia, Chile.
| |
Collapse
|
5
|
Stapleton EM, Thurman AL, Pezzulo AA, Comellas AP, Thornell IM. Increased ENaC-mediated liquid absorption across vitamin-D deficient human airway epithelia. Am J Physiol Cell Physiol 2024; 326:C540-C550. [PMID: 38145296 DOI: 10.1152/ajpcell.00369.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2023] [Revised: 12/01/2023] [Accepted: 12/18/2023] [Indexed: 12/26/2023]
Abstract
Vitamin D deficiency is a risk factor for exacerbation of obstructive airway disease, a hallmark of which is mucus dehydration and plugging. Calcitriol (the active form of vitamin D) deficiency in cultured human airway epithelia resulted in increased SCNN1G and ATP1B1 mRNAs encoding subunits of ENaC and the Na-K pump compared with supplemented epithelia. These drive the absorption of airway surface liquid. Consistently, calcitriol-deficient epithelia absorbed liquid faster than supplemented epithelia. Calcitriol deficiency also increased amiloride-sensitive Isc and Gt without altering Na-K pump activity, indicating the changes in amiloride-sensitivity arose from ENaC. ENaC activity can be regulated by trafficking, proteases, and channel abundance. We found the effect was likely not induced by changes to endocytosis of ENaC given that calcitriol did not affect the half-lives of amiloride-sensitive Isc and Gt. Furthermore, trypsin nominally increased Isc produced by epithelia ± calcitriol, suggesting calcitriol did not affect proteolytic activation of ENaC. Consistent with mRNA and functional data, calcitriol deficiency resulted in increased γENaC protein. These data indicate that the vitamin D receptor response controls ENaC function and subsequent liquid absorption, providing insight into the relationship between vitamin D deficiency and respiratory disease.NEW & NOTEWORTHY It is unknown why calcitriol (active vitamin D) deficiency worsens pulmonary disease outcomes. Results from mRNA, immunoblot, Ussing chamber, and absorption experiments indicate that calcitriol deficiency increases ENaC activity in human airway epithelia, decreasing apical hydration. Given that epithelial hydration is required for mucociliary transport and airway innate immune function, the increased ENaC activity observed in calcitriol-deficient epithelia may contribute to respiratory pathology observed in vitamin D deficiency.
Collapse
Affiliation(s)
- Emma M Stapleton
- Division of Pulmonary, Critical Care and Occupational Medicine, Department of Internal Medicine, University of Iowa, Iowa City, Iowa, United States
| | - Andrew L Thurman
- Division of Pulmonary, Critical Care and Occupational Medicine, Department of Internal Medicine, University of Iowa, Iowa City, Iowa, United States
| | - Alejandro A Pezzulo
- Division of Pulmonary, Critical Care and Occupational Medicine, Department of Internal Medicine, University of Iowa, Iowa City, Iowa, United States
| | - Alejandro P Comellas
- Division of Pulmonary, Critical Care and Occupational Medicine, Department of Internal Medicine, University of Iowa, Iowa City, Iowa, United States
| | - Ian M Thornell
- Division of Pulmonary, Critical Care and Occupational Medicine, Department of Internal Medicine, University of Iowa, Iowa City, Iowa, United States
| |
Collapse
|
6
|
Lu Y, Liu X, Sun L, Zhang D, Fan P, Yang K, Zhang L, Liu Y, Zhou X. A frameshift mutation in the SCNN1B gene in a family with Liddle syndrome: A case report and systematic review. Mol Med Rep 2024; 29:19. [PMID: 38099339 PMCID: PMC10784729 DOI: 10.3892/mmr.2023.13142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Accepted: 10/31/2023] [Indexed: 12/18/2023] Open
Abstract
Liddle syndrome is an autosomal dominant form of monogenic hypertension that is caused by mutations in SCNN1A, SCNN1B or SCNN1G, which respectively encode the α, β and γ subunits of the epithelial sodium channel. In the present study, DNA was extracted from leukocytes in peripheral blood obtained from all members of a family with Liddle syndrome. Whole‑exome sequencing and Sanger sequencing were performed to assess the candidate variant and a co‑segregation analysis was conducted. A frameshift mutation in SCNN1B (NM_ 000336: c.1806dupG, p.Pro603Alafs*5) in the family was identified, characterized by early‑onset hypertension and hypokalemia. The mutation led to the truncation of the β subunit of the epithelial sodium channel and a lack of the conservative PY motif. Furthermore, a systematic review of follow‑up data from patients with Liddle syndrome with SCNN1B mutations was performed. The follow‑up data of 108 patients with pathogenic SCNN1B mutations from 47 families were summarized. Phenotypic heterogeneity was evident in patients with Liddle syndrome and early‑onset hypertension was the most frequent symptom. Patients responded well to targeted amiloride therapy with significant improvements in blood pressure and serum potassium concentration. The present study demonstrates that confirmatory genetic testing and targeted therapy can prevent premature onset of clinical endpoint events in patients with Liddle syndrome.
Collapse
Affiliation(s)
- Yiting Lu
- Department of Cardiology, National Center for Cardiovascular Diseases, Fuwai Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100037, P.R. China
| | - Xinchang Liu
- Department of Cardiology, National Center for Cardiovascular Diseases, Fuwai Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100037, P.R. China
| | - Lin Sun
- Department of Cardiology, National Center for Cardiovascular Diseases, Fuwai Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100037, P.R. China
| | - Di Zhang
- Department of Cardiology, National Center for Cardiovascular Diseases, Fuwai Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100037, P.R. China
| | - Peng Fan
- Department of Cardiology, National Center for Cardiovascular Diseases, Fuwai Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100037, P.R. China
| | - Kunqi Yang
- Department of Cardiology, National Center for Cardiovascular Diseases, Fuwai Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100037, P.R. China
| | - Lin Zhang
- Department of Cardiology, National Center for Cardiovascular Diseases, Fuwai Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100037, P.R. China
| | - Yaxin Liu
- Emergency and Critical Care Center, National Center for Cardiovascular Diseases, Fuwai Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100037, P.R. China
| | - Xianliang Zhou
- Department of Cardiology, National Center for Cardiovascular Diseases, Fuwai Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100037, P.R. China
| |
Collapse
|
7
|
Lysikova DV, Vasileva VY, Chubinskiy-Nadezhdin VI, Morachevskaya EA, Sudarikova AV. Capsazepine activates amiloride-insensitive ENaC-like channels in human leukemia cells. Biochem Biophys Res Commun 2023; 687:149187. [PMID: 37944472 DOI: 10.1016/j.bbrc.2023.149187] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Revised: 10/27/2023] [Accepted: 10/30/2023] [Indexed: 11/12/2023]
Abstract
Sodium influx carried out by ion channels is one of the main regulators of water-salt and volume balance in cells of blood origin. Previously, we described amiloride-insensitive ENaC-like channels in human myeloid leukemia K562 cells; the intracellular regulatory mechanisms of the channels are associated with actin cytoskeleton dynamics. Recently, an extracellular mechanism of ENaC-like channels activation in K562 cells by the action of serine protease trypsin has been revealed. The other extracellular pathways that modulate ENaC (epithelial Na+ channel) activity and sodium permeability in transformed blood cells are not yet fully investigated. Here, we study the action of capsazepine (CPZ), as δ-ENaC activator, on single channel activity in K562 cells in whole-cell patch clamp experiments. Addition of CPZ (2 μM) to the extracellular solution caused an activation of sodium channels with typical features; unitary conductance was 15.1 ± 0.8 pS. Amiloride derivative benzamil (50 μM) did not inhibit their activity. Unitary currents and conductance of CPZ-activated channels were higher in Na+-containing extracellular solution than in Li+, that is one of the main fingerprints of δ-ENaC. The results of RT-PCR analysis and immunofluorescence staining also confirmed the expression of δ-hENaC (as well as α-, β-, γ-ENaC) at the mRNA and protein level. These findings allow us to speculate that CPZ activates amiloride-insensitive ENaC-like channels that contain δ-ENaC in К562 cells. Our data reveal a novel extracellular mechanism for ENaC-like activation in human leukemia cells.
Collapse
Affiliation(s)
- Daria V Lysikova
- Institute of Cytology, Russian Academy of Sciences, 194064 Tikhoretsky Ave. 4, St. Petersburg, Russia
| | - Valeria Y Vasileva
- Institute of Cytology, Russian Academy of Sciences, 194064 Tikhoretsky Ave. 4, St. Petersburg, Russia
| | | | - Elena A Morachevskaya
- Institute of Cytology, Russian Academy of Sciences, 194064 Tikhoretsky Ave. 4, St. Petersburg, Russia
| | - Anastasia V Sudarikova
- Institute of Cytology, Russian Academy of Sciences, 194064 Tikhoretsky Ave. 4, St. Petersburg, Russia.
| |
Collapse
|
8
|
Sainz de Los Terreros Errea A, Madariaga L, García-Castaño A. Hypercalcemia in patients with mutations in NR3C2 and SCNN1B. Med Clin (Barc) 2023; 161:458-459. [PMID: 37596163 DOI: 10.1016/j.medcli.2023.06.041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Revised: 06/25/2023] [Accepted: 06/27/2023] [Indexed: 08/20/2023]
Affiliation(s)
| | - Leire Madariaga
- Sección de Nefrología Pedíátrica, IIS Biocruces Bizkaia, Universidad del País Vasco UOV/EHU, Ciberdem/Ciberer/Endo-ERN, Hospital Universitario Cruces, Barakaldo, Bizkaia, España
| | - Alejandro García-Castaño
- Laboratorio de Investigación, IIS Biocruces Bizkaia, Ciberdem/Ciberer/Endo-ERN Hospital Universitario Cruces, Barakaldo, Bizkaia, España
| |
Collapse
|
9
|
Nickerson AJ, Mutchler SM, Sheng S, Cox NA, Ray EC, Kashlan OB, Carattino MD, Marciszyn AL, Winfrey A, Gingras S, Kirabo A, Hughey RP, Kleyman TR. Mice lacking γENaC palmitoylation sites maintain benzamil-sensitive Na+ transport despite reduced channel activity. JCI Insight 2023; 8:e172051. [PMID: 37707951 PMCID: PMC10721255 DOI: 10.1172/jci.insight.172051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Accepted: 09/12/2023] [Indexed: 09/16/2023] Open
Abstract
Epithelial Na+ channels (ENaCs) control extracellular fluid volume by facilitating Na+ absorption across transporting epithelia. In vitro studies showed that Cys-palmitoylation of the γENaC subunit is a major regulator of channel activity. We tested whether γ subunit palmitoylation sites are necessary for channel function in vivo by generating mice lacking the palmitoylated cysteines (γC33A,C41A) using CRISPR/Cas9 technology. ENaCs in dissected kidney tubules from γC33A,C41A mice had reduced open probability compared with wild-type (WT) littermates maintained on either standard or Na+-deficient diets. Male mutant mice also had higher aldosterone levels than WT littermates following Na+ restriction. However, γC33A,C41A mice did not have reduced amiloride-sensitive Na+ currents in the distal colon or benzamil-induced natriuresis compared to WT mice. We identified a second, larger conductance cation channel in the distal nephron with biophysical properties distinct from ENaC. The activity of this channel was higher in Na+-restricted γC33A,C41A versus WT mice and was blocked by benzamil, providing a possible compensatory mechanism for reduced prototypic ENaC function. We conclude that γ subunit palmitoylation sites are required for prototypic ENaC activity in vivo but are not necessary for amiloride/benzamil-sensitive Na+ transport in the distal nephron or colon.
Collapse
Affiliation(s)
| | | | | | | | | | - Ossama B. Kashlan
- Department of Medicine
- Department of Computational and Systems Biology
| | | | | | | | - Sebastien Gingras
- Department of Immunology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Annet Kirabo
- Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | | | - Thomas R. Kleyman
- Department of Medicine
- Department of Cell Biology, and
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| |
Collapse
|
10
|
Harris ES, Novak L, Fernandez-Petty CM, Lindgren NR, Baker SM, Birket SE, Rowe SM. SNSP113 (PAAG) improves mucociliary transport and lung pathology in the Scnn1b-Tg murine model of CF lung disease. J Cyst Fibros 2023; 22:1104-1112. [PMID: 37714777 PMCID: PMC10843010 DOI: 10.1016/j.jcf.2023.08.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Revised: 07/25/2023] [Accepted: 08/29/2023] [Indexed: 09/17/2023]
Abstract
BACKGROUND Mucus stasis, a hallmark of muco-obstructive disease, results from impaired mucociliary transport and leads to lung function decline and chronic infection. Although therapeutics that target mucus stasis in the airway, such as hypertonic saline or rhDNAse, show some therapeutic benefit, they do not address the underlying electrostatic defect apparent in mucins in CF and related conditions. We have previously shown poly (acetyl, arginyl) glucosamine (PAAG, developed as SNSP113), a soluble, cationic polymer, significantly improves mucociliary transport in a rat model of CF by normalizing the charge defects of CF mucin. Here, we report efficacy in the CFTR-sufficient, ENaC hyperactive, Scnn1b-Tg mouse model that develops airway muco-obstruction due to sodium hyperabsorption and airway dehydration. METHODS Scnn1b-Tg mice were treated with either 250 µg/mL SNSP113 or vehicle control (1.38% glycerol in PBS) via nebulization once daily for 7 days and then euthanized for analysis. Micro-Optical Coherence Tomography-based evaluation of excised mouse trachea was used to determine the effect on the functional microanatomy. Tissue analysis was performed by routine histopathology. RESULTS Nebulized treatment of SNSP113 significantly improved mucociliary transport in the airways of Scnn1b-Tg mice, without altering the airway surface or periciliary liquid layer. In addition, SNSP113 significantly reversed epithelial hypertrophy and goblet cell metaplasia. Finally, SNSP113 significantly ameliorated eosinophilic crystalline pneumonia and lung consolidation in addition to inflammatory macrophage influx in this model. CONCLUSION Overall, this study extends the efficacy of SNSP113 as a potential therapeutic to alleviate mucus stasis in muco-obstructive diseases in CF and potentially in related conditions.
Collapse
Affiliation(s)
- Elex S Harris
- Gregory Fleming James Cystic Fibrosis Research Center, Univ. of Alabama at Birmingham, Birmingham, AL, USA
| | - Lea Novak
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Courtney M Fernandez-Petty
- Gregory Fleming James Cystic Fibrosis Research Center, Univ. of Alabama at Birmingham, Birmingham, AL, USA
| | - Natalie R Lindgren
- Gregory Fleming James Cystic Fibrosis Research Center, Univ. of Alabama at Birmingham, Birmingham, AL, USA
| | | | - Susan E Birket
- Gregory Fleming James Cystic Fibrosis Research Center, Univ. of Alabama at Birmingham, Birmingham, AL, USA; Departments of Pediatrics, and Cell Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Steven M Rowe
- Gregory Fleming James Cystic Fibrosis Research Center, Univ. of Alabama at Birmingham, Birmingham, AL, USA; Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA; Departments of Pediatrics, and Cell Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL, USA.
| |
Collapse
|
11
|
Wang S, Ma J, Li X, Xian X, Tan G, Cai H, Yang B, Zhang A, Guo J, Gu G, Meng Z, Fu B. EGR-1 Contributes to Pulmonary Edema by Regulating the Epithelial Sodium Channel in Lipopolysaccharide-Induced Acute Lung Injury. Immunol Invest 2023; 52:925-939. [PMID: 37732637 DOI: 10.1080/08820139.2023.2256778] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/22/2023]
Abstract
Acute lung injury (ALI) is a common lung disease with increasing morbidity and mortality rates due to the lack of specific drugs. Impaired alveolar fluid clearance (AFC) is a primary pathological feature of ALI. Epithelial sodium channel (ENaC) is a primary determinant in regulating the transport of Na+ and the clearance of alveolar edema fluid. Therefore, ENaC is an important target for the development of drugs for ALI therapy. However, the role of ENaC in the progression of ALI remains unclear. Inhibition of early growth response factor (EGR-1) expression has been reported to induce a protective effect on ALI; therefore, we evaluated whether EGR-1 participates in the progression of ALI by regulating ENaC-α in alveolar epithelium. We investigated the potential mechanism of EGR-1-mediated regulation of ENaC in ALI. We investigated whether EGR-1 aggravates the pulmonary edema response in ALI by regulating ENaC. ALI mouse models were established by intrabronchial injection of lipopolysaccharides (LPS). Lentiviruses with EGR-1 knockdown were transfected into LPS-stimulated A549 cells. We found that EGR-1 expression was upregulated in the lung tissues of ALI mice and in LPS-induced A549 cells, and was negatively correlated with ENaC-α expression. Knockdown of EGR-1 increased ENaC-α expression and relieved cellular edema in ALI. Moreover, EGR-1 regulated ENaC-α expression at the transcriptional level, and correspondingly promoted pulmonary edema and aggravated ALI symptoms. In conclusion, our study demonstrated that EGR-1 could promote pulmonary edema by downregulating ENaC-α at the transcriptional level in ALI. Our study provides a new potential therapeutic strategy for treatment of ALI.
Collapse
Affiliation(s)
- Song Wang
- Precision Biomedical Laboratory, Liaocheng People's Hospital, Liaocheng, China
| | - Jing Ma
- Office of Academic Research, Liaocheng People's Hospital, Liaocheng, China
| | - Xin Li
- Department of Clinical Laboratory, Zibo Central Hospital, Zibo, China
| | - Xinmiao Xian
- Precision Biomedical Laboratory, Liaocheng People's Hospital, Liaocheng, China
| | - Guikun Tan
- Pharmacy Department, Liaocheng Woman and Child Health Care Hospital, Liaocheng, China
| | - Hongwei Cai
- Department of Critical Care Medicine, Yantai Affiliated Hospital of Binzhou Medical University, Yantai, China
| | - Bingwu Yang
- Precision Biomedical Laboratory, Liaocheng People's Hospital, Liaocheng, China
| | - Anqi Zhang
- Central Laboratory, Liaocheng People's Hospital, Liaocheng, China
| | - Jianran Guo
- Precision Biomedical Laboratory, Liaocheng People's Hospital, Liaocheng, China
| | - Guohao Gu
- Precision Biomedical Laboratory, Liaocheng People's Hospital, Liaocheng, China
| | - Zhen Meng
- Biomedical Laboratory, Medical School of Liaocheng University, Liaocheng, China
| | - Bo Fu
- Precision Biomedical Laboratory, Liaocheng People's Hospital, Liaocheng, China
| |
Collapse
|
12
|
Sun H, Zhou Y, Jiang S, Zhao D, Li H, Lu Y, Ma B, Zhou B. Association between low-sodium salt intervention and long-term blood pressure changes is modified by ENaC genetic variation: a gene-diet interaction analysis in a randomized controlled trial. Food Funct 2023; 14:9782-9791. [PMID: 37843257 DOI: 10.1039/d3fo02393a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2023]
Abstract
Background: Hypertension is closely associated with excessive sodium intake, and low-sodium salt has been shown to lower blood pressure. However, whether low-sodium salt interacts with genetic variation related to salt sensitivity of blood pressure is unclear. Methods: A total of 259 hypertensive patients who completed the previous 3 years of a low-sodium salt vs. normal salt intervention were included in our study. Genetic risk scores (GRSs) of systolic blood pressure (SBP) and diastolic blood pressure (DBP) were respectively built for each participant. A general linear regression model and a generalized mixed model were applied to identify the interaction effects between low-sodium salt intervention and ENaC genetic variation on SBP/DBP changes and trajectories over 3 years. Findings: during the 3-year intervention, both SBP and DBP levels showed a significant decline in the low-sodium salt intervention group than those in the normal salt intervention group over 3 years (Psalt intervention group = 0.001 for SBP and Psalt intervention group = 0.006 for DBP). Furthermore, a gene-diet interaction was found for the SBP change trajectory over 3 years (PSBP-GRS×salt intervention group = 0.011); specifically, significant SBP reductions were found between salt intervention groups in the high SBP-GRS group (-18.77 vs. -9.58 mmHg, Psalt intervention group = 0.001), but not in the low SBP-GRS group (-15.71 vs. -14.62 mmHg, Psalt intervention group = 0.791). No interaction effect between low-sodium salt intervention and genetic variation of ENaC was found for changes in DBP. Conclusions: Higher ENaC genetic variation is associated with a greater reduction in SBP in response to a low-sodium salt intervention. Hypertensive patients with higher ENaC genetic variation may experience a greater benefit in SBP reductions by consuming low-sodium salt. (Trial registration: chiCTR-TRC-09000538, https://www.chictr.org.cn).
Collapse
Affiliation(s)
- Hao Sun
- Department of Clinical Epidemiology and Evidence-based Medicine, the First Hospital of China Medical University, 155 Nanjing North Street, Heping District, 110001, Shenyang, Liaoning, China.
| | - Ying Zhou
- Department of Cardiology, the First Hospital of China Medical University, 155 Nanjing North Street, Heping District, 110001, Shenyang, Liaoning, China
| | - Shuyi Jiang
- Center of Reproductive Medicine, Shengjing Hospital of China Medical University, 36 Sanhao Street, Heping District, 110001, Shenyang, Liaoning, China
| | - Dan Zhao
- Department of Clinical Epidemiology and Evidence-based Medicine, the First Hospital of China Medical University, 155 Nanjing North Street, Heping District, 110001, Shenyang, Liaoning, China.
| | - Huamin Li
- Department of Clinical Epidemiology and Evidence-based Medicine, the First Hospital of China Medical University, 155 Nanjing North Street, Heping District, 110001, Shenyang, Liaoning, China.
| | - Yue Lu
- Department of Clinical Epidemiology and Evidence-based Medicine, the First Hospital of China Medical University, 155 Nanjing North Street, Heping District, 110001, Shenyang, Liaoning, China.
| | - Bing Ma
- Department of Clinical Epidemiology and Evidence-based Medicine, the First Hospital of China Medical University, 155 Nanjing North Street, Heping District, 110001, Shenyang, Liaoning, China.
| | - Bo Zhou
- Department of Clinical Epidemiology and Evidence-based Medicine, the First Hospital of China Medical University, 155 Nanjing North Street, Heping District, 110001, Shenyang, Liaoning, China.
| |
Collapse
|
13
|
Lyukmanova EN, Zaigraev MM, Kulbatskii DS, Isaev AB, Kukushkin ID, Bychkov ML, Shulepko MA, Chugunov AO, Kirpichnikov MP. Molecular Basis for Mambalgin-2 Interaction with Heterotrimeric α-ENaC/ASIC1a/γ-ENaC Channels in Cancer Cells. Toxins (Basel) 2023; 15:612. [PMID: 37888643 PMCID: PMC10610865 DOI: 10.3390/toxins15100612] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Revised: 09/30/2023] [Accepted: 10/07/2023] [Indexed: 10/28/2023] Open
Abstract
Cancer progression is characterized by microenvironmental acidification. Tumor cells adapt to low environmental pH by activating acid-sensing trimeric ion channels of the DEG/ENaC family. The α-ENaC/ASIC1a/γ-ENaC heterotrimeric channel is a tumor-specific acid-sensing channel, and its targeting can be considered a new strategy for cancer therapy. Mambalgin-2 from the Dendroaspis polylepis venom inhibits the α-ENaC/ASIC1a/γ-ENaC heterotrimer more effectively than the homotrimeric ASIC1a channel, initially proposed as the target of mambalgin-2. Although the molecular basis of such mambalgin selectivity remained unclear. Here, we built the models of the complexes of mambalgin-2 with the α-ENaC/ASIC1a/γ-ENaC and ASIC1a channels, performed MD and predicted the difference in the binding modes. The importance of the 'head' loop region of mambalgin-2 for the interaction with the hetero-, but not with the homotrimeric channel was confirmed by site-directed mutagenesis and electrophysiology. A new mode of allosteric regulation of the ENaC channels by linking the thumb domain of the ASIC1a subunit with the palm domain of the γ-ENaC subunit was proposed. The data obtained provide new insights into the regulation of various types of acid-sensing ion channels and the development of new strategies for cancer treatment.
Collapse
Affiliation(s)
- Ekaterina N. Lyukmanova
- Faculty of Biology, MSU-BIT Shenzhen University, Shenzhen 518172, China;
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya 16/10, Moscow 117997, Russia; (M.M.Z.); (D.S.K.); (A.B.I.); (I.D.K.); (M.L.B.); (A.O.C.); (M.P.K.)
- Phystech School of Biological and Medical Physics, Moscow Institute of Physics and Technology (National Research University), Institutsky Lane 9, Dolgoprudny, Moscow 141701, Russia
- Interdisciplinary Scientific and Educational School of Moscow University «Molecular Technologies of the Living Systems and Synthetic Biology», Faculty of Biology, Lomonosov Moscow State University, Leninskie Gory, Moscow 119234, Russia
| | - Maxim M. Zaigraev
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya 16/10, Moscow 117997, Russia; (M.M.Z.); (D.S.K.); (A.B.I.); (I.D.K.); (M.L.B.); (A.O.C.); (M.P.K.)
- Phystech School of Biological and Medical Physics, Moscow Institute of Physics and Technology (National Research University), Institutsky Lane 9, Dolgoprudny, Moscow 141701, Russia
| | - Dmitrii S. Kulbatskii
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya 16/10, Moscow 117997, Russia; (M.M.Z.); (D.S.K.); (A.B.I.); (I.D.K.); (M.L.B.); (A.O.C.); (M.P.K.)
| | - Aizek B. Isaev
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya 16/10, Moscow 117997, Russia; (M.M.Z.); (D.S.K.); (A.B.I.); (I.D.K.); (M.L.B.); (A.O.C.); (M.P.K.)
- Phystech School of Biological and Medical Physics, Moscow Institute of Physics and Technology (National Research University), Institutsky Lane 9, Dolgoprudny, Moscow 141701, Russia
| | - Ilya D. Kukushkin
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya 16/10, Moscow 117997, Russia; (M.M.Z.); (D.S.K.); (A.B.I.); (I.D.K.); (M.L.B.); (A.O.C.); (M.P.K.)
- Phystech School of Biological and Medical Physics, Moscow Institute of Physics and Technology (National Research University), Institutsky Lane 9, Dolgoprudny, Moscow 141701, Russia
| | - Maxim L. Bychkov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya 16/10, Moscow 117997, Russia; (M.M.Z.); (D.S.K.); (A.B.I.); (I.D.K.); (M.L.B.); (A.O.C.); (M.P.K.)
| | | | - Anton O. Chugunov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya 16/10, Moscow 117997, Russia; (M.M.Z.); (D.S.K.); (A.B.I.); (I.D.K.); (M.L.B.); (A.O.C.); (M.P.K.)
- Phystech School of Biological and Medical Physics, Moscow Institute of Physics and Technology (National Research University), Institutsky Lane 9, Dolgoprudny, Moscow 141701, Russia
| | - Mikhail P. Kirpichnikov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya 16/10, Moscow 117997, Russia; (M.M.Z.); (D.S.K.); (A.B.I.); (I.D.K.); (M.L.B.); (A.O.C.); (M.P.K.)
- Interdisciplinary Scientific and Educational School of Moscow University «Molecular Technologies of the Living Systems and Synthetic Biology», Faculty of Biology, Lomonosov Moscow State University, Leninskie Gory, Moscow 119234, Russia
| |
Collapse
|
14
|
Ramachandran CD, Gholami K, Lam SK, Hoe SZ. Effects of a high-salt diet on MAP and expression levels of renal ENaCs and aquaporins in SHR. Exp Biol Med (Maywood) 2023; 248:1768-1779. [PMID: 37828834 PMCID: PMC10792424 DOI: 10.1177/15353702231198085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Accepted: 06/05/2023] [Indexed: 10/14/2023] Open
Abstract
An increase in blood pressure by a high-salt (HS) diet may change the expression levels of renal epithelial sodium channels (ENaCs) and aquaporins (AQPs). Spontaneously hypertensive rats (SHRs) and Wistar Kyoto (WKY) rats were exposed to HS and regular-salt (RS) diets for 6 weeks. Mean arterial pressure (MAP) and plasma atrial natriuretic peptide (ANP), angiotensin II (Ang II), aldosterone, and arginine vasopressin (AVP) levels were determined. Expression of mRNA levels of ENaCs and AQPs were quantified by real-time PCR. The MAP was higher in SHRs on the HS diet. Plasma Ang II and aldosterone levels were low while plasma ANP level was high in both strains of rats. Renal expression of mRNA levels of α-, β-, and γ-ENaCs was lowered in SHRs on the HS diet. Meanwhile, renal AQP1, AQP2, and AQP7 mRNA expression levels were lowered in both strains of rats on the HS diet. Suppression of mRNA expression levels of ENaC and AQP subunits suggests that the high-salt-induced increase in the MAP of SHR may not be solely due to renal sodium and water retention.
Collapse
Affiliation(s)
| | - Khadijeh Gholami
- Department of Physiology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur 50603, Malaysia
- Department of Endocrinology, Diabetes and Hypertension, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Sau-Kuen Lam
- Department of Physiology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur 50603, Malaysia
- Department of Pre-Clinical Sciences, Faculty of Medicine & Health Sciences, Universiti Tunku Abdul Rahman, Kajang 43000, Malaysia
| | - See-Ziau Hoe
- Department of Physiology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur 50603, Malaysia
| |
Collapse
|
15
|
Serrano-Morillas N, González-Alayón C, Vastola-Mascolo A, Rodríguez-Rodríguez AE, Hernández G, Porrini E, Hernández-Guerra M, Alvarez de la Rosa D. Decaying kidney function during cirrhosis correlates with remodeling of distal colon aldosterone target gene expression. Am J Physiol Gastrointest Liver Physiol 2023; 325:G306-G317. [PMID: 37461846 DOI: 10.1152/ajpgi.00073.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Revised: 06/21/2023] [Accepted: 07/12/2023] [Indexed: 08/03/2023]
Abstract
Liver cirrhosis is associated to circulatory abnormalities leading to hypovolemia and stimulation of the renin-angiotensin-aldosterone system (RAAS). Advanced stages of the disease cause renal failure, impairing K+ and Na+ homeostasis. It has been proposed that the distal colon undergoes functional remodeling during renal failure, in particular by aldosterone-driven increased K+ excretion. In this study, we compared the transcriptional response of aldosterone target genes in the rat distal colon under two models of increased circulating aldosterone (one with concomitant RAAS activation) and in a model of secondary hyperaldosteronism induced by cirrhosis. The expression of a subset of these genes was also tested in distal colon biopsies from control subjects or patients with cirrhosis with varying levels of disease progression and treated or not with mineralocorticoid receptor inhibitor spironolactone. We examined known aldosterone-regulated transcripts involved in corticosteroid signaling and transepithelial ion transport. In addition, we included aldosterone-regulated genes related to cell proliferation. Our comparison revealed multiple aldosterone target genes upregulated in the rat distal colon during decompensated cirrhosis. Epithelial Na+ channel β and γ subunit expression correlated positively with plasma aldosterone concentration and negatively with glomerular filtration rate. Patients with cirrhosis showed increased expression of 11-β-hydroxysteroid-dehydrogenase 2 (11βHSD2), which was reverted by spironolactone treatment, suggesting a sensitization of the distal colon to aldosterone action. In summary, our data show that decaying kidney function during cirrhosis progression toward a decompensated state with hypovolemia correlates with remodeling of distal colon ion transporter expression, supporting a role for aldosterone in the process.NEW & NOTEWORTHY Liver cirrhosis progression significantly alters ion transporter subunit expression in the rat distal colon, a change that correlated well with declining kidney function and the severity of the disease. Our data suggest that the steroid hormone aldosterone participates in this homeostatic response to maintain electrolyte balance.
Collapse
Affiliation(s)
- Natalia Serrano-Morillas
- Departamento de Ciencias Médicas Básicas, Universidad de La Laguna, La Laguna, Spain
- Instituto de Tecnologías Biomédicas, Universidad de La Laguna, La Laguna, Spain
| | | | - Arianna Vastola-Mascolo
- Departamento de Ciencias Médicas Básicas, Universidad de La Laguna, La Laguna, Spain
- Instituto de Tecnologías Biomédicas, Universidad de La Laguna, La Laguna, Spain
| | - Ana E Rodríguez-Rodríguez
- Instituto de Tecnologías Biomédicas, Universidad de La Laguna, La Laguna, Spain
- Research Unit, Hospital Universitario de Canarias, La Laguna, Spain
| | - Guadalberto Hernández
- Departamento de Ciencias Médicas Básicas, Universidad de La Laguna, La Laguna, Spain
- Instituto de Tecnologías Biomédicas, Universidad de La Laguna, La Laguna, Spain
| | - Esteban Porrini
- Instituto de Tecnologías Biomédicas, Universidad de La Laguna, La Laguna, Spain
- Research Unit, Hospital Universitario de Canarias, La Laguna, Spain
| | - Manuel Hernández-Guerra
- Instituto de Tecnologías Biomédicas, Universidad de La Laguna, La Laguna, Spain
- Research Unit, Hospital Universitario de Canarias, La Laguna, Spain
- Servicio de Aparato Digestivo, Hospital Universitario de Canarias, La Laguna, Spain
| | - Diego Alvarez de la Rosa
- Departamento de Ciencias Médicas Básicas, Universidad de La Laguna, La Laguna, Spain
- Instituto de Tecnologías Biomédicas, Universidad de La Laguna, La Laguna, Spain
| |
Collapse
|
16
|
Yan Y, Zhang Y, Zhang J, Ying L. SCNN1B regulates the proliferation, migration, and collagen deposition of human lung fibroblasts. In Vitro Cell Dev Biol Anim 2023; 59:479-485. [PMID: 37477776 DOI: 10.1007/s11626-023-00787-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Accepted: 06/08/2023] [Indexed: 07/22/2023]
Abstract
The aim of this study was to investigate the role of amiloride-sensitive sodium channel protein 1B (SCNN1B) on the proliferation and migration of human lung fibroblasts and the possible mechanism that promote the development of acute respiratory distress syndrome (ARDS). Cultivate human embryonic lung fibroblasts (MRC-5) in vitro and screen out the most effective small interfering RNA to silence the expression of SCNN1B. Then, quantitative real-time PCR (qRT-PCR), CCK-8, Transwell, and Western blot detections were performed separately. The results of qRT-PCR showed that all three SCNN1B siRNAs were able to significantly decrease the mRNA expression level of SCNN1B compared with the si-NC group (P < 0.01), with the most significant decrease in the SCNN1B siRNA-83 group. Additionally, compared with the si-NC group, the proliferation ability of MRC-5 cells in the si-SCNN1B group was significantly enhanced, and the migration rate was significantly decreased (P < 0.01). Western blot results showed that low expression of SCNN1B significantly inhibited the protein expression levels of collagen deposition related proteins Collagen I and Heat shock proteins 47 (P < 0.01). In summary, SCNN1B can inhibit cell proliferation and promote cell migration and extracellular matrix deposition of human lung fibroblasts, and may be involved in the occurrence and development of ARDS.
Collapse
Affiliation(s)
- Yihe Yan
- Department of Critical Care Medicine, Shaoxing People's Hospital, Shaoxing, Zhejiang, 312000, China
| | - Yiting Zhang
- Department of Critical Care Medicine, Shaoxing People's Hospital, Shaoxing, Zhejiang, 312000, China
| | - Juanqi Zhang
- Department of Critical Care Medicine, Shaoxing People's Hospital, Shaoxing, Zhejiang, 312000, China
| | - Lijun Ying
- Department of Critical Care Medicine, Shaoxing People's Hospital, Shaoxing, Zhejiang, 312000, China.
| |
Collapse
|
17
|
Ellison DH, McCormick JA. mTORC2, a Novel " Twist " on the Epithelial Sodium Channel (ENaC). J Am Soc Nephrol 2023; 34:937-938. [PMID: 37052952 PMCID: PMC10278834 DOI: 10.1681/asn.0000000000000131] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/14/2023] Open
Affiliation(s)
- David H. Ellison
- Division of Nephrology and Hypertension, Department of Medicine, Oregon Health and Science University, Portland, Oregon
- Oregon Clinical and Translational Research Institute, Oregon Health and Science University, Portland, Oregon
- VA Portland Health Care System, Portland, Oregon
| | - James A. McCormick
- Division of Nephrology and Hypertension, Department of Medicine, Oregon Health and Science University, Portland, Oregon
| |
Collapse
|
18
|
Loffing J, Pech V, Loffing-Cueni D, Abood DC, Kim YH, Chen C, Pham TD, Verlander JW, Wall SM. Pendrin abundance, subcellular distribution, and function are unaffected by either αENaC gene ablation or by increasing ENaC channel activity. Pflugers Arch 2023; 475:607-620. [PMID: 36977894 PMCID: PMC10105674 DOI: 10.1007/s00424-023-02797-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Revised: 01/20/2023] [Accepted: 02/13/2023] [Indexed: 03/30/2023]
Abstract
The intercalated cell Cl-/HCO3- exchanger, pendrin, modulates ENaC subunit abundance and function. Whether ENaC modulates pendrin abundance and function is however unknown. Because αENaC mRNA has been detected in pendrin-positive intercalated cells, we hypothesized that ENaC, or more specifically the αENaC subunit, modulates intercalated cell function. The purpose of this study was therefore to determine if αENaC is expressed at the protein level in pendrin-positive intercalated cells and to determine if αENaC gene ablation or constitutively upregulating ENaC activity changes pendrin abundance, subcellular distribution, and/or function. We observed diffuse, cytoplasmic αENaC label in pendrin-positive intercalated cells from both mice and rats, with much lower label intensity in pendrin-negative, type A intercalated cells. However, while αENaC gene ablation within principal and intercalated cells of the CCD reduced Cl- absorption, it did not change pendrin abundance or subcellular distribution in aldosterone-treated mice. Further experiments used a mouse model of Liddle's syndrome to explore the effect of increasing ENaC channel activity on pendrin abundance and function. The Liddle's variant did not increase either total or apical plasma membrane pendrin abundance in aldosterone-treated or in NaCl-restricted mice. Similarly, while the Liddle's mutation increased total Cl- absorption in CCDs from aldosterone-treated mice, it did not significantly affect the change in Cl- absorption seen with pendrin gene ablation. We conclude that in rats and mice, αENaC localizes to pendrin-positive ICs where its physiological role remains to be determined. While pendrin modulates ENaC abundance, subcellular distribution, and function, ENaC does not have a similar effect on pendrin.
Collapse
Affiliation(s)
- Johannes Loffing
- Institute of Anatomy, University of Zurich, Zurich, Switzerland.
| | - Vladimir Pech
- Division of Renal Medicine, Department of Medicine, Emory University, Atlanta, GA, 30322, USA
| | | | - Delaney C Abood
- Division of Renal Medicine, Department of Medicine, Emory University, Atlanta, GA, 30322, USA
| | - Young Hee Kim
- Division of Renal Medicine, Department of Medicine, Emory University, Atlanta, GA, 30322, USA
| | - Chao Chen
- The Division of Nephrology, Hypertension and Renal Transplantation, The University of Florida College of Medicine, Gainesville, FL, USA
| | - Truyen D Pham
- Division of Renal Medicine, Department of Medicine, Emory University, Atlanta, GA, 30322, USA
| | - Jill W Verlander
- The Division of Nephrology, Hypertension and Renal Transplantation, The University of Florida College of Medicine, Gainesville, FL, USA
| | - Susan M Wall
- Division of Renal Medicine, Department of Medicine, Emory University, Atlanta, GA, 30322, USA.
| |
Collapse
|
19
|
Mohammadifard N, Moazeni F, Azizian-Farsani F, Gharipour M, Khosravi E, Sadeghian L, Mansouri A, Shirani S, Sarrafzadegan N. Genetic variation in salt taste receptors impact salt intake and blood pressure. Sci Rep 2023; 13:4037. [PMID: 36899055 PMCID: PMC10006406 DOI: 10.1038/s41598-022-23827-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Accepted: 03/14/2022] [Indexed: 03/12/2023] Open
Abstract
So far, few studies have examined the effect of salt taste receptors genetic variation on dietary intake in the Iranian population. We aimed to evaluate associations between single nucleotide polymorphisms (SNPs) in salt taste receptors' genes with dietary salt intake and blood pressure. A cross-sectional study was carried out among 116 randomly selected healthy adults aged ≥ 18 in Isfahan, Iran. Participants underwent sodium intake determination by 24-h urine collection, as well as dietary assessment by semi-quantitative food frequency questionnaire and blood pressure measurement. Whole blood was collected to extract DNA and genotype of SNP rs239345 in SCNN1B and rs224534, rs4790151 and rs8065080 in TRPV1 gene. Sodium consumption and diastolic blood pressure were significantly higher in carriers of the A-allele in rs239345 compared to subjects with the TT genotype (4808.4 ± 824.4 mg/day vs. 4043.5 ± 989.3 mg/day; P = 0.004) and 83.6 ± 8.5 mmHg vs. 77.3 ± 7.3 mmHg; P = 0.011), respectively. The level of sodium intake was lower in the TT genotype of TRPV1 (rs224534) than the CC genotype (3767.0 ± 713.7 mg/day vs. 4633.3 ± 793.5 mg/day; P = 0.012). We could not find any association between genotypes of all SNPs with systolic blood pressure as well as genotypes of rs224534, rs4790151 and rs8065080 with diastolic blood pressure. Genetic variations can relate with salt intake and consequently may associate with hypertension and finally cardiovascular disease risk in the Iranian population.
Collapse
Affiliation(s)
- Noushin Mohammadifard
- Isfahan Cardiovascular Research Center, Cardiovascular Research Institute, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Faezeh Moazeni
- Department of Clinical Nutrition, School of Nutrition and Food Science, Food Security Research Center, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Fatemeh Azizian-Farsani
- Interventional Cardiology Research Center, Cardiovascular Research Institute, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Mojgan Gharipour
- Cardiac Rehabilitation Research Center, Cardiovascular Research Institute, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Elham Khosravi
- Heart Failure Research Center, Cardiovascular Research Institute, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Ladan Sadeghian
- Perdiatric Cardiovascular Research Center, Cardiovascular Research Institute, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Asieh Mansouri
- Hypertension Research Center, Cardiovascular Research Institute, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Shahin Shirani
- Department of Cardiology, Tehran University of Medical Science, Dr Ali Shariati Hospital, Tehran, Iran.
| | - Nizal Sarrafzadegan
- Isfahan Cardiovascular Research Center, Cardiovascular Research Institute, Isfahan University of Medical Sciences, Isfahan, Iran
| |
Collapse
|
20
|
Yao Z, Yuan L, Chen X, Wang Q, Chai L, Lu X, Yang F, Wang Y, Yang S. A thermal receptor for nonvisual sunlight detection in myriapods. Proc Natl Acad Sci U S A 2023; 120:e2218948120. [PMID: 36780532 PMCID: PMC9974506 DOI: 10.1073/pnas.2218948120] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Accepted: 01/11/2023] [Indexed: 02/15/2023] Open
Abstract
Organisms from cyanobacteria to humans have evolved a wide array of photoreceptive strategies to detect light. Sunlight avoidance behavior is common in animals without vision or known photosensory genes. While indirect light perception via photothermal conversion is a possible scenario, there is no experimental evidence for this hypothesis. Here, we show a nonvisual and extraocular sunlight detection mechanism by identifying the broad-range thermal receptor 1 (BRTNaC1, temperature range = 33 to 48 °C) in centipede antennae. BRTNaC1, a heat-activated cation-permeable ion channel, is structurally related to members of the epithelial sodium channel family. At the molecular level, heat activation of BRTNaC1 exhibits strong pH dependence controlled by two protonatable sites. Physiologically, temperature-dependent activation of BRTNaC1 upon sunlight exposure comes from a striking photothermal effect on the antennae, where a slightly acidic environment (pH 6.1) of the body fluid leads to the protonation of BRTNaC1 and switches on its high thermal sensitivity. Furthermore, testosterone potently inhibits heat activation of BRTNaC1 and the sunlight avoidance behavior of centipedes. Taken together, our study suggests a sophisticated strategy for nonvisual sunlight detection in myriapods.
Collapse
Affiliation(s)
- Zhihao Yao
- College of Wildlife and Protected Area, Northeast Forestry University150040Harbin, China
| | - Licheng Yuan
- College of Wildlife and Protected Area, Northeast Forestry University150040Harbin, China
| | - Xiaoying Chen
- Department of Biophysics and Kidney Disease Center of the First Affiliated Hospital, Zhejiang University School of Medicine310058Hangzhou, China
| | - Qian Wang
- College of Wildlife and Protected Area, Northeast Forestry University150040Harbin, China
| | - Longhui Chai
- College of Wildlife and Protected Area, Northeast Forestry University150040Harbin, China
| | - Xiancui Lu
- College of Wildlife and Protected Area, Northeast Forestry University150040Harbin, China
| | - Fan Yang
- Department of Biophysics and Kidney Disease Center of the First Affiliated Hospital, Zhejiang University School of Medicine310058Hangzhou, China
| | - Yunfei Wang
- College of Wildlife and Protected Area, Northeast Forestry University150040Harbin, China
| | - Shilong Yang
- College of Wildlife and Protected Area, Northeast Forestry University150040Harbin, China
| |
Collapse
|
21
|
Azurmendi PJ, Toro AR, Celía AF, Guevara D, Solerno MR, Di Ciano LA, Toledo JE, Ibarra FR, Arrizurieta EE, Oddo EM. Behavior of the renal kallikrein in spontaneously hypertensive rats: Influence of sexual hormones and aldosterone-sensitive distal nephron ion channels. Peptides 2023; 160:170925. [PMID: 36549423 DOI: 10.1016/j.peptides.2022.170925] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Revised: 12/01/2022] [Accepted: 12/15/2022] [Indexed: 12/24/2022]
Abstract
The renal kallikrein-kinin system (RKKS) has been related to blood pressure control and sodium and water balance. We have previously shown that female spontaneously hypertensive rats (SHR) have high urinary kallikrein activity (UKa) and lower blood pressure (BP) than males whereas ovariectomy stimulates UKa and diminishes BP. We also showed that high K+ intake and prepuberal gonadectomy (Gx) diminish BP with a concomitant increase in UKa and plasma aldosterone levels. Since kallikrein co-localize in the same distal nephron segments of aldosterone effectors, we explored the effect of pharmacological blockage of aldosterone receptor, epithelial Na+ (ENaC) and the rectifying outer medulla K+ (ROMK) channels in different gonad contexts on the gene expression, renal tissue content and urine release of kallikrein. Klk1 gene expression was determined by real-time PCR and enzymatic activity of kallikrein by the amidolytic method. We found that the inhibition of the aldosterone receptor by spironolactone increases kallikrein renal tissue storage and decreases its urinary activity, especially in Gx rats. Moreover, ENaC blockade by benzamil increases the renal content of kallikrein without affecting synthesis or excretion, especially in females and Gx animals, while the inhibition of ROMK by glibenclamide increases the synthesis and renal content of kallikrein only in intact male animals. We concluded that RKKS regulation showed sexual dimorphism and seemed to be modulated by sex hormones throughout a process involving aldosterone and the aldosterone-sensitive ion channels..
Collapse
Affiliation(s)
- Pablo Javier Azurmendi
- Universidad de Buenos Aires, Laboratorio de Nefrología Experimental y Bioquímica Molecular, Instituto de Investigaciones Médicas A. Lanari, Buenos Aires, Argentina.
| | - Ayelén Rayen Toro
- Universidad de Buenos Aires, Laboratorio de Nefrología Experimental y Bioquímica Molecular, Instituto de Investigaciones Médicas A. Lanari, Buenos Aires, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
| | - Alejandro Fabián Celía
- Universidad de Buenos Aires, Laboratorio de Nefrología Experimental y Bioquímica Molecular, Instituto de Investigaciones Médicas A. Lanari, Buenos Aires, Argentina
| | - Darío Guevara
- Universidad de Buenos Aires, Laboratorio de Nefrología Experimental y Bioquímica Molecular, Instituto de Investigaciones Médicas A. Lanari, Buenos Aires, Argentina
| | - Martín Rogelio Solerno
- Universidad de Buenos Aires, Laboratorio de Nefrología Experimental y Bioquímica Molecular, Instituto de Investigaciones Médicas A. Lanari, Buenos Aires, Argentina
| | - Luis Alberto Di Ciano
- Universidad de Buenos Aires, Laboratorio de Nefrología Experimental y Bioquímica Molecular, Instituto de Investigaciones Médicas A. Lanari, Buenos Aires, Argentina
| | - Jorge Eduardo Toledo
- Universidad de Buenos Aires, Laboratorio de Nefrología Experimental y Bioquímica Molecular, Instituto de Investigaciones Médicas A. Lanari, Buenos Aires, Argentina
| | - Fernando Raúl Ibarra
- Universidad de Buenos Aires, Laboratorio de Nefrología Experimental y Bioquímica Molecular, Instituto de Investigaciones Médicas A. Lanari, Buenos Aires, Argentina; Universidad de Buenos Aires, Departamento de Ciencias Fisiológicas, Instituto de Fisiología y Biofísica Bernardo Houssay (IFIBIO Houssay)-CONICET, Facultad de Medicina, Buenos Aires, Argentina
| | - Elvira Emilia Arrizurieta
- Universidad de Buenos Aires, Laboratorio de Nefrología Experimental y Bioquímica Molecular, Instituto de Investigaciones Médicas A. Lanari, Buenos Aires, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
| | - Elisabet Mónica Oddo
- Universidad de Buenos Aires, Laboratorio de Nefrología Experimental y Bioquímica Molecular, Instituto de Investigaciones Médicas A. Lanari, Buenos Aires, Argentina
| |
Collapse
|
22
|
Shabbir W, Susan Yang KH, Dogar AM, Isaev D, Oz M. Probing the Ubiquitination-Mediated Function of Epithelial Sodium Channel in A549 Cells. Curr Mol Pharmacol 2023; 16:411-418. [PMID: 35894469 DOI: 10.2174/1874467215666220726112002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 04/25/2022] [Accepted: 05/07/2022] [Indexed: 11/22/2022]
Abstract
BACKGROUND The activity of the amiloride-sensitive epithelial sodium channel (ENaC) in the tight epithelia of the lung is regulated by proteolytic activation and ubiquitination. Pathophysiology of lung diseases is directly related to changes in one or both of these mechanisms. METHODS In this study, we investigated the impact of ubiquitination and cathepsin-mediated proteolytic activation mechanisms on the functional regulation of ENaC in lung cancer A549 cells using the patch-clamp technique. RESULTS Our findings suggest that inhibiting the proteasome (polyubiquitination) with MG132 improves ENaC activity, whereas altering the pH of the lysosome (monoubiquitination inhibition) with NH4Cl has no effect on ENaC activity. In A549 cells, inhibition of cathepsin B (CSTB) decreased the ENaC current, open probabilities (NPo and Po), and the number of active channels. CONCLUSION These findings delineate novel modes of ENaC degradation and proteolytic activation of functional channels in A549 cells. Our findings indicate that both proteolytic activation and ubiquitination of ENaC significantly affect channel function and add new insights into the endogenous ENaC processing which might help to further understand the pathophysiology of the lung disease.
Collapse
Affiliation(s)
- Waheed Shabbir
- Department of Cellular Membranology, Bogomoletz Institute of Physiology, Kyiv, Ukraine
| | - Keun-Hang Susan Yang
- Department of Biological Sciences, Schmid College of Science and Technology, Chapman University, One University Drive, Orange, CA 92866, USA
| | - Afzal M Dogar
- Department of Biology, Syed Babar Ali School of Science and Engineering, Lahore University of Management Sciences, Lahore, Pakistan
| | - Dmytro Isaev
- Department of Cellular Membranology, Bogomoletz Institute of Physiology, Kyiv, Ukraine
| | - Murat Oz
- Department of Pharmacology and Therapeutics, Faculty of Pharmacy, Kuwait University, Safat, 13110, Kuwait
| |
Collapse
|
23
|
Mareš Š, Filipovský J. Liddle syndrome. Vnitr Lek 2022; 68:8-11. [PMID: 36575060 DOI: 10.36290/vnl.2022.115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Liddle syndrome is an inherited form of arterial hypertension with autosomal dominant pattern of inheritance. It is caused by activating mutation of genes coding of the epithelial sodium channel in distal nephron. Mutation leads to excessive reabsorbtion of sodium ions and volume expansion resulting in arterial hypertension. Antoher typical laboratory findings are hypokalaemia, low levels of serum aldosteron and metabolic alkalosis. Phenotypic variability makes it difficult to identify patients with Liddle syndrome, often resulting in misdiagnosis and severe complications at early age. Genetic studies should be done to confirm the diagnosis. Therapy of Liddle syndrome is based on administration of epithelial sodium channel blocker amilorid.
Collapse
|
24
|
Mironova E, Archer CR, Vendrov AE, Runge MS, Madamanchi NR, Arendshorst WJ, Stockand JD, Abd El-Aziz TM. NOXA1-dependent NADPH oxidase 1 signaling mediates angiotensin II activation of the epithelial sodium channel. Am J Physiol Renal Physiol 2022; 323:F633-F641. [PMID: 36201326 PMCID: PMC9705023 DOI: 10.1152/ajprenal.00107.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Revised: 10/03/2022] [Accepted: 10/04/2022] [Indexed: 12/14/2022] Open
Abstract
The activity of the epithelial Na+ channel (ENaC) in principal cells of the distal nephron fine-tunes renal Na+ excretion. The renin-angiotensin-aldosterone system modulates ENaC activity to control blood pressure, in part, by influencing Na+ excretion. NADPH oxidase activator 1-dependent NADPH oxidase 1 (NOXA1/NOX1) signaling may play a key role in angiotensin II (ANG II)-dependent activation of ENaC. The present study aimed to explore the role of NOXA1/NOX1 signaling in ANG II-dependent activation of ENaC in renal principal cells. Patch-clamp electrophysiology and principal cell-specific Noxa1 knockout (PC-Noxa1 KO) mice were used to determine the role of NOXA1/NOX1 signaling in ANG II-dependent activation of ENaC. The activity of ENaC in the luminal plasma membrane of principal cells was quantified in freshly isolated split-opened tubules using voltage-clamp electrophysiology. ANG II significantly increased ENaC activity. This effect was robust and observed in response to both acute (40 min) and more chronic (48-72 h) ANG II treatment of isolated tubules and mice, respectively. Inhibition of ANG II type 1 receptors with losartan abolished ANG II-dependent stimulation of ENaC. Similarly, treatment with ML171, a specific inhibitor of NOX1, abolished stimulation of ENaC by ANG II. Treatment with ANG II failed to increase ENaC activity in principal cells in tubules isolated from the PC-Noxa1 KO mouse. Tubules from wild-type littermate controls, though, retained their ability to respond to ANG II with an increase in ENaC activity. These results indicate that NOXA1/NOX1 signaling mediates ANG II stimulation of ENaC in renal principal cells. As such, NOXA1/NOX1 signaling in the distal nephron plays a central role in Na+ homeostasis and control of blood pressure, particularly as it relates to regulation by the renin-ANG II axis.NEW & NOTEWORTHY Activity of the epithelial Na+ channel (ENaC) in the distal nephron fine-tunes renal Na+ excretion. Angiotensin II (ANG II) has been reported to enhance ENaC activity. Emerging evidence suggests that NADPH oxidase (NOX) signaling plays an important role in the stimulation of ENaC by ANG II in principal cells. The present findings indicate that NOX activator 1/NOX1 signaling mediates ANG II stimulation of ENaC in renal principal cells.
Collapse
Affiliation(s)
- Elena Mironova
- Department of Cellular and Integrative Physiology, University of Texas Health Science Center at San Antonio, San Antonio, Texas
| | - Crystal R Archer
- Department of Cellular and Integrative Physiology, University of Texas Health Science Center at San Antonio, San Antonio, Texas
| | | | | | | | - William J Arendshorst
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, North Carolina
| | - James D Stockand
- Department of Cellular and Integrative Physiology, University of Texas Health Science Center at San Antonio, San Antonio, Texas
| | - Tarek Mohamed Abd El-Aziz
- Department of Cellular and Integrative Physiology, University of Texas Health Science Center at San Antonio, San Antonio, Texas
- Department of Zoology, Minia University, El-Minia, Egypt
| |
Collapse
|
25
|
Saha B, Leite-Dellova DCA, Demko J, Sørensen MV, Takagi E, Gleason CE, Shabbir W, Pearce D. WNK1 is a chloride-stimulated scaffold that regulates mTORC2 activity and ion transport. J Cell Sci 2022; 135:jcs260313. [PMID: 36373794 PMCID: PMC9789407 DOI: 10.1242/jcs.260313] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Accepted: 10/26/2022] [Indexed: 11/16/2022] Open
Abstract
Mammalian (or mechanistic) target of rapamycin complex 2 (mTORC2) is a kinase complex that targets predominantly Akt family proteins, SGK1 and protein kinase C (PKC), and has well-characterized roles in mediating hormone and growth factor effects on a wide array of cellular processes. Recent evidence suggests that mTORC2 is also directly stimulated in renal tubule cells by increased extracellular K+ concentration, leading to activation of the Na+ channel, ENaC, and increasing the electrical driving force for K+ secretion. We identify here a signaling mechanism for this local effect of K+. We show that an increase in extracellular [K+] leads to a rise in intracellular chloride (Cl-), which stimulates a previously unknown scaffolding activity of the protein 'with no lysine-1' (WNK1) kinase. WNK1 interacts selectively with SGK1 and recruits it to mTORC2, resulting in enhanced SGK1 phosphorylation and SGK1-dependent activation of ENaC. This scaffolding effect of WNK1 is independent of its own kinase activity and does not cause a generalized stimulation of mTORC2 kinase activity. These findings establish a novel WNK1-dependent regulatory mechanism that harnesses mTORC2 kinase activity selectively toward SGK1 to control epithelial ion transport and electrolyte homeostasis.
Collapse
Affiliation(s)
- Bidisha Saha
- Division of Nephrology, Departments of Medicine and Cellular & Molecular Pharmacology,University of California at San Francisco, San Francisco, CA 94158, USA
| | - Deise C. A. Leite-Dellova
- Department of Veterinary Medicine, Faculty of Animal Science and Food Engineering, University of São Paulo, Pirassununga, Sao Paulo 13635-900, Brazil
| | - John Demko
- Division of Nephrology, Departments of Medicine and Cellular & Molecular Pharmacology,University of California at San Francisco, San Francisco, CA 94158, USA
| | - Mads Vaarby Sørensen
- Departments of Biomedicine and Physiology, Aarhus University, 8000 Aarhus C, Denmark
| | - Enzo Takagi
- Division of Nephrology, Departments of Medicine and Cellular & Molecular Pharmacology,University of California at San Francisco, San Francisco, CA 94158, USA
| | - Catherine E. Gleason
- Division of Nephrology, Departments of Medicine and Cellular & Molecular Pharmacology,University of California at San Francisco, San Francisco, CA 94158, USA
| | - Waheed Shabbir
- Division of Nephrology, Departments of Medicine and Cellular & Molecular Pharmacology,University of California at San Francisco, San Francisco, CA 94158, USA
| | - David Pearce
- Division of Nephrology, Departments of Medicine and Cellular & Molecular Pharmacology,University of California at San Francisco, San Francisco, CA 94158, USA
| |
Collapse
|
26
|
Wagner C, Balázs A, Schatterny J, Zhou-Suckow Z, Duerr J, Schultz C, Mall MA. Genetic Deletion of Mmp9 Does Not Reduce Airway Inflammation and Structural Lung Damage in Mice with Cystic Fibrosis-like Lung Disease. Int J Mol Sci 2022; 23:13405. [PMID: 36362203 PMCID: PMC9657231 DOI: 10.3390/ijms232113405] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Revised: 10/25/2022] [Accepted: 10/28/2022] [Indexed: 09/10/2023] Open
Abstract
Elevated levels of matrix metalloprotease 9 (MMP-9) and neutrophil elastase (NE) are associated with bronchiectasis and lung function decline in patients with cystic fibrosis (CF). MMP-9 is a potent extracellular matrix-degrading enzyme which is activated by NE and has been implicated in structural lung damage in CF. However, the role of MMP-9 in the in vivo pathogenesis of CF lung disease is not well understood. Therefore, we used β-epithelial Na+ channel-overexpressing transgenic (βENaC-Tg) mice as a model of CF-like lung disease and determined the effect of genetic deletion of Mmp9 (Mmp9-/-) on key aspects of the pulmonary phenotype. We found that MMP-9 levels were elevated in the lungs of βENaC-Tg mice compared with wild-type littermates. Deletion of Mmp9 had no effect on spontaneous mortality, inflammatory markers in bronchoalveolar lavage, goblet cell metaplasia, mucus hypersecretion and emphysema-like structural lung damage, while it partially reduced mucus obstruction in βENaC-Tg mice. Further, lack of Mmp9 had no effect on increased inspiratory capacity and increased lung compliance in βENaC-Tg mice, whereas both lung function parameters were improved with genetic deletion of NE. We conclude that MMP-9 does not play a major role in the in vivo pathogenesis of CF-like lung disease in mice.
Collapse
Affiliation(s)
- Claudius Wagner
- Department of Translational Pulmonology, University of Heidelberg, 69117 Heidelberg, Germany
- Translational Lung Research Center (TLRC), Member of the German Center for Lung Research (DZL), Im Neuenheimer Feld 156, 69120 Heidelberg, Germany
| | - Anita Balázs
- Department of Pediatric Respiratory Medicine, Immunology and Critical Care Medicine, Charité—Universitätsmedizin Berlin, Augustenburger Platz 1, 13353 Berlin, Germany
- Berlin Institute of Health, Charité—Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany
| | - Jolanthe Schatterny
- Department of Translational Pulmonology, University of Heidelberg, 69117 Heidelberg, Germany
- Translational Lung Research Center (TLRC), Member of the German Center for Lung Research (DZL), Im Neuenheimer Feld 156, 69120 Heidelberg, Germany
| | - Zhe Zhou-Suckow
- Department of Translational Pulmonology, University of Heidelberg, 69117 Heidelberg, Germany
- Translational Lung Research Center (TLRC), Member of the German Center for Lung Research (DZL), Im Neuenheimer Feld 156, 69120 Heidelberg, Germany
| | - Julia Duerr
- Department of Pediatric Respiratory Medicine, Immunology and Critical Care Medicine, Charité—Universitätsmedizin Berlin, Augustenburger Platz 1, 13353 Berlin, Germany
- Berlin Institute of Health, Charité—Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany
| | - Carsten Schultz
- Translational Lung Research Center (TLRC), Member of the German Center for Lung Research (DZL), Im Neuenheimer Feld 156, 69120 Heidelberg, Germany
- Department of Chemical Physiology and Biochemistry, Oregon Health & Science University, Portland, OR 97239, USA
| | - Marcus A. Mall
- Department of Pediatric Respiratory Medicine, Immunology and Critical Care Medicine, Charité—Universitätsmedizin Berlin, Augustenburger Platz 1, 13353 Berlin, Germany
- Berlin Institute of Health, Charité—Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany
- German Center for Lung Research (DZL), Associated Partner Site, Augustenburger Platz 1, 13353 Berlin, Germany
| |
Collapse
|
27
|
Nemeth Z, Hildebrandt E, Parsa N, Fleming AB, Wasson R, Pittman K, Bell X, Granger JP, Ryan MJ, Drummond HA. Epithelial sodium channels in macrophage migration and polarization: role of proinflammatory cytokines TNFα and IFNγ. Am J Physiol Regul Integr Comp Physiol 2022; 323:R763-R775. [PMID: 36189990 PMCID: PMC9639769 DOI: 10.1152/ajpregu.00207.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Revised: 09/13/2022] [Accepted: 09/26/2022] [Indexed: 11/22/2022]
Abstract
Migration of monocytes-macrophages plays an important role in phagocytosis of pathogens and cellular debris in a variety of pathophysiological conditions. Although epithelial Na+ channels (ENaCs) are required for normal migratory responses in other cell types, their role in macrophage migration signaling is unknown. To address this possibility, we determined whether ENaC message is present in several peripheral blood monocyte cell populations and tissue-resident macrophages in healthy humans using the Human Protein Atlas database (www.proteinatlas.org) and the mouse monocyte cell line RAW 264.7 using RT-PCR. We then determined that selective ENaC inhibition with amiloride inhibited chemotactic migration (∼50%), but not phagocytosis, of the mouse monocyte-macrophage cell line RAW 264.7. Furthermore, we generated a cell line stably expressing an NH2-terminal truncated αENaC to interrupt normal channel trafficking and found it suppressed migration. Prolonged exposure (48 h) of RAW 264.7 cells to proinflammatory cytokines interferon γ (IFNγ) and/or tumor necrosis factor α (TNFα) inhibited RAW 264.7 migration and abolished the amiloride (1 µM)-sensitive component of migration, a finding consistent with ENaC downregulation. To determine if proinflammatory cytokines regulate αENaC protein expression, cells were exposed to proinflammatory cytokines IFNγ (10 ng/mL, last 48 h) and TNFα (10 ng/mL, last 24 h). By Western blot analysis, we found whole cell αENaC protein is reduced ≥50%. Immunofluorescence demonstrated heterogeneous αENaC inhibition. Finally, we found that overnight exposure to amiloride stimulated morphological changes and increased polarization marker expression. Our findings suggest that ENaC may be a critical molecule in macrophage migration and polarization.
Collapse
Affiliation(s)
- Zoltan Nemeth
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, Mississippi
| | - Emily Hildebrandt
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, Mississippi
| | - Nicholas Parsa
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, Mississippi
| | - Adam B Fleming
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, Mississippi
| | - Robert Wasson
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, Mississippi
| | - Katarina Pittman
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, Mississippi
| | - Xavier Bell
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, Mississippi
| | - Joey P Granger
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, Mississippi
| | - Michael J Ryan
- Department of Pharmacology, Physiology and Neuroscience, University of South Carolina School of Medicine, Columbia, South Carolina
| | - Heather A Drummond
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, Mississippi
| |
Collapse
|
28
|
Blobner BM, Kirabo A, Kashlan OB, Sheng S, Arnett DK, Becker LC, Boerwinkle E, Carlson JC, Gao Y, Gibbs RA, He J, Irvin MR, Kardia SLR, Kelly TN, Kooperberg C, McGarvey ST, Menon VK, Montasser ME, Naseri T, Redline S, Reiner AP, Reupena MS, Smith JA, Sun X, Vaidya D, Viaud-Martinez KA, Weeks DE, Yanek LR, Zhu X, Minster RL, Kleyman TR. Rare Variants in Genes Encoding Subunits of the Epithelial Na + Channel Are Associated With Blood Pressure and Kidney Function. Hypertension 2022; 79:2573-2582. [PMID: 36193739 PMCID: PMC9669116 DOI: 10.1161/hypertensionaha.121.18513] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Accepted: 07/31/2022] [Indexed: 11/16/2022]
Abstract
BACKGROUND The epithelial Na+ channel (ENaC) is intrinsically linked to fluid volume homeostasis and blood pressure. Specific rare mutations in SCNN1A, SCNN1B, and SCNN1G, genes encoding the α, β, and γ subunits of ENaC, respectively, are associated with extreme blood pressure phenotypes. No associations between blood pressure and SCNN1D, which encodes the δ subunit of ENaC, have been reported. A small number of sequence variants in ENaC subunits have been reported to affect functional transport in vitro or blood pressure. The effects of the vast majority of rare and low-frequency ENaC variants on blood pressure are not known. METHODS We explored the association of low frequency and rare variants in the genes encoding ENaC subunits, with systolic blood pressure, diastolic blood pressure, mean arterial pressure, and pulse pressure. Using whole-genome sequencing data from 14 studies participating in the Trans-Omics in Precision Medicine Whole-Genome Sequencing Program, and sequence kernel association tests. RESULTS We found that variants in SCNN1A and SCNN1B were associated with diastolic blood pressure and mean arterial pressure (P<0.00625). Although SCNN1D is poorly expressed in human kidney tissue, SCNN1D variants were associated with systolic blood pressure, diastolic blood pressure, mean arterial pressure, and pulse pressure (P<0.00625). ENaC variants in 2 of the 4 subunits (SCNN1B and SCNN1D) were also associated with estimated glomerular filtration rate (P<0.00625), but not with stroke. CONCLUSIONS Our results suggest that variants in extrarenal ENaCs, in addition to ENaCs expressed in kidneys, influence blood pressure and kidney function.
Collapse
Affiliation(s)
- Brandon M Blobner
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Annet Kirabo
- Division of Clinical Pharmacology, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Ossama B Kashlan
- Renal-Electrolyte Division, Department of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
- Department of Computational and Systems Biology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Shaohu Sheng
- Renal-Electrolyte Division, Department of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Donna K Arnett
- College of Public Health, University of Kentucky, Lexington, KY, USA
| | - Lewis C Becker
- GeneSTAR Research Program, Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Eric Boerwinkle
- Department of Epidemiology, Human Genetics, and Environmental Sciences, School of Public Health, The University of Texas Health Science Center at Houston, Houston, TX, USA
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX, USA
| | - Jenna C Carlson
- Department of Biostatistics, University of Pittsburgh Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA, USA
- Department of Human Genetics, University of Pittsburgh Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA, USA
| | - Yan Gao
- Department of Medicine, University of Mississippi Medical Center, Jackson, MS, USA
| | - Richard A Gibbs
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX, USA
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Jiang He
- Department of Epidemiology, Tulane University School of Public Health and Tropical Medicine, New Orleans, LA, USA
- Tulane University Translational Science Institute, New Orleans, LA, USA
| | - Marguerite R Irvin
- Department of Epidemiology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Sharon LR Kardia
- Department of Epidemiology, School of Public Health, University of Michigan, Ann Arbor, MI, USA
| | - Tanika N Kelly
- Department of Epidemiology, Tulane University School of Public Health and Tropical Medicine, New Orleans, LA, USA
- Tulane University Translational Science Institute, New Orleans, LA, USA
| | - Charles Kooperberg
- Division of Public Health Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Stephen T McGarvey
- Department of Epidemiology and International Health Institute, Brown University School of Public Health, Providence, RI, USA
| | - Vipin K Menon
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX, USA
| | - May E Montasser
- Department of Medicine, University of Maryland, Baltimore, MD, USA
| | - Take Naseri
- Department of Epidemiology and International Health Institute, Brown University School of Public Health, Providence, RI, USA
- Ministry of Health, Apia, Samoa
| | - Susan Redline
- Division of Sleep and Circadian Disorders, Department of Medicine, Brigham and Women’s Hospital, Boston, MA, USA
- Harvard Medical School, Boston, MA, USA
- Department of Medicine, Beth Israel Deaconess Medical Center, Boston, MA, USA
| | - Alexander P Reiner
- Division of Public Health Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | | | - Jennifer A Smith
- Department of Epidemiology, School of Public Health, University of Michigan, Ann Arbor, MI, USA
| | - Xiao Sun
- Department of Epidemiology, Tulane University School of Public Health and Tropical Medicine, New Orleans, LA, USA
| | - Dhananjay Vaidya
- GeneSTAR Research Program, Division of General Internal Medicine, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | | | - Daniel E Weeks
- Department of Biostatistics, University of Pittsburgh Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA, USA
- Department of Human Genetics, University of Pittsburgh Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA, USA
| | - Lisa R Yanek
- GeneSTAR Research Program, Division of General Internal Medicine, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Xiaofeng Zhu
- Department of Population and Quantitative Health Sciences, Case Western Reserve University, Cleveland, OH, USA
| | | | - Ryan L Minster
- Department of Human Genetics, University of Pittsburgh Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA, USA
| | - Thomas R Kleyman
- Renal-Electrolyte Division, Department of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
- Department of Cell Biology, University of Pittsburgh School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| |
Collapse
|
29
|
Montalbetti N, Przepiorski AJ, Shi S, Sheng S, Baty CJ, Maggiore JC, Carattino MD, Vanichapol T, Davidson AJ, Hukriede NA, Kleyman TR. Functional characterization of ion channels expressed in kidney organoids derived from human induced pluripotent stem cells. Am J Physiol Renal Physiol 2022; 323:F479-F491. [PMID: 35979965 PMCID: PMC9529267 DOI: 10.1152/ajprenal.00365.2021] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 08/15/2022] [Accepted: 08/16/2022] [Indexed: 02/04/2023] Open
Abstract
Kidney organoids derived from human or rodent pluripotent stem cells have glomerular structures and differentiated/polarized nephron segments. Although there is an increasing understanding of the patterns of expression of transcripts and proteins within kidney organoids, there is a paucity of data regarding functional protein expression, in particular on transporters that mediate the vectorial transport of solutes. Using cells derived from kidney organoids, we examined the functional expression of key ion channels that are expressed in distal nephron segments: the large-conductance Ca2+-activated K+ (BKCa) channel, the renal outer medullary K+ (ROMK, Kir1.1) channel, and the epithelial Na+ channel (ENaC). RNA-sequencing analyses showed that genes encoding the pore-forming subunits of these transporters, and for BKCa channels, key accessory subunits, are expressed in kidney organoids. Expression and localization of selected ion channels was confirmed by immunofluorescence microscopy and immunoblot analysis. Electrophysiological analysis showed that BKCa and ROMK channels are expressed in different cell populations. These two cell populations also expressed other unidentified Ba2+-sensitive K+ channels. BKCa expression was confirmed at a single channel level, based on its high conductance and voltage dependence of activation. We also found a population of cells expressing amiloride-sensitive ENaC currents. In summary, our results show that human kidney organoids functionally produce key distal nephron K+ and Na+ channels.NEW & NOTEWORTHY Our results show that human kidney organoids express key K+ and Na+ channels that are expressed on the apical membranes of cells in the aldosterone-sensitive distal nephron, including the large-conductance Ca2+-activated K+ channel, renal outer medullary K+ channel, and epithelial Na+ channel.
Collapse
Affiliation(s)
| | - Aneta J Przepiorski
- Department of Developmental Biology, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Shujie Shi
- Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Shaohu Sheng
- Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Catherine J Baty
- Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Joseph C Maggiore
- Department of Developmental Biology, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Marcelo D Carattino
- Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
- Department of Cell Biology, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Thitinee Vanichapol
- Department of Molecular Medicine and Pathology, School of Medical Sciences, University of Auckland, Auckland, New Zealand
| | - Alan J Davidson
- Department of Molecular Medicine and Pathology, School of Medical Sciences, University of Auckland, Auckland, New Zealand
| | - Neil A Hukriede
- Department of Developmental Biology, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Thomas R Kleyman
- Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
- Department of Cell Biology, University of Pittsburgh, Pittsburgh, Pennsylvania
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, Pennsylvania
| |
Collapse
|
30
|
Gao F, Wang D, Liu X, Wu YH, Wang HT, Sun SL. Sodium channel 1 subunit alpha SCNN1A exerts oncogenic function in pancreatic cancer via accelerating cellular growth and metastasis. Arch Biochem Biophys 2022; 727:109323. [PMID: 35714697 DOI: 10.1016/j.abb.2022.109323] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 06/05/2022] [Accepted: 06/10/2022] [Indexed: 11/24/2022]
Abstract
The identification of new diagnostic and therapeutic biomarkers might be helpful to understand molecular mechanism of cancer pathogenesis and develop anti-cancer targets. This study reported the alteration of Sodium channel 1 subunit alpha (SCNN1A) expression, its prognostic significance and biological roles in pancreatic cancer. Bioinformatics database was searched to explore the expression of SCNN1A in pancreatic cancer specimens and analysis results were further validated by qRT-PCR and Western blot assay. The correlation between SCNN1A expression and clinicopathological characteristics and its impact on survival outcome of pancreatic cancer patients were investigated using GEPIA database and Kaplan-Meier plotter. Loss- and gain-of-functional experiments in vitro were done to investigate the biological function of SCNN1A in pancreatic cancer. Bioinformatics analysis and validation experiment showed that SCNN1A was frequently overexpressed in pancreatic cancer specimens and cell lines (P < 0.001), and there were significant relevance between high SCNN1A expression and TP53 mutation (P < 0.05) as well as unfavorable prognosis of pancreatic cancer patients (HR for overall survival: 1.9, P = 0.003 and HR for disease-free survival: 1.7, P = 0.014). The silencing of SCNN1A suppressed cell proliferation, migration and invasion and induced cell apoptosis (P < 0.05), while its overexpression promoted aggressive phenotypes of pancreatic cancer cells in vitro (P < 0.05). SCNN1A possessed oncogenic function and its dysregulation could be implicated in the development and metastasis of pancreatic cancer.
Collapse
Affiliation(s)
- Feng Gao
- Department of General Surgery, Shengjing Hospital of China Medical University, Shenyang, Liaoning, 110004, China
| | - Dan Wang
- Department of Pancreatic Surgery, Shengjing Hospital of China Medical University, Shenyang, Liaoning, 110004, China
| | - Xun Liu
- Department of General Surgery, Shengjing Hospital of China Medical University, Shenyang, Liaoning, 110004, China
| | - Yun-Hao Wu
- Department of Pancreatic Surgery, Shengjing Hospital of China Medical University, Shenyang, Liaoning, 110004, China
| | - Huai-Tao Wang
- Department of Pancreatic Surgery, Shengjing Hospital of China Medical University, Shenyang, Liaoning, 110004, China
| | - Shao-Long Sun
- Department of General Surgery, Shengjing Hospital of China Medical University, Shenyang, Liaoning, 110004, China.
| |
Collapse
|
31
|
Pitzer A, Elijovich F, Laffer CL, Ertuglu LA, Sahinoz M, Saleem M, Krishnan J, Dola T, Aden LA, Sheng Q, Raddatz MA, Wanjalla C, Pakala S, Davies SS, Patrick DM, Kon V, Ikizler TA, Kleyman T, Kirabo A. DC ENaC-Dependent Inflammasome Activation Contributes to Salt-Sensitive Hypertension. Circ Res 2022; 131:328-344. [PMID: 35862128 PMCID: PMC9357159 DOI: 10.1161/circresaha.122.320818] [Citation(s) in RCA: 30] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Salt sensitivity of blood pressure is an independent predictor of cardiovascular morbidity and mortality. The exact mechanism by which salt intake increases blood pressure and cardiovascular risk is unknown. We previously found that sodium entry into antigen-presenting cells (APCs) via the amiloride-sensitive epithelial sodium channel EnaC (epithelial sodium channel) leads to the formation of IsoLGs (isolevuglandins) and release of proinflammatory cytokines to activate T cells and modulate salt-sensitive hypertension. In the current study, we hypothesized that ENaC-dependent entry of sodium into APCs activates the NLRP3 (NOD [nucleotide-binding and oligomerization domain]-like receptor family pyrin domain containing 3) inflammasome via IsoLG formation leading to salt-sensitive hypertension. METHODS We performed RNA sequencing on human monocytes treated with elevated sodium in vitro and Cellular Indexing of Transcriptomes and Epitopes by Sequencing analysis of peripheral blood mononuclear cells from participants rigorously phenotyped for salt sensitivity of blood pressure using an established inpatient protocol. To determine mechanisms, we analyzed inflammasome activation in mouse models of deoxycorticosterone acetate salt-induced hypertension as well as salt-sensitive mice with ENaC inhibition or expression, IsoLG scavenging, and adoptive transfer of wild-type dendritic cells into NLRP3 deficient mice. RESULTS We found that high levels of salt exposure upregulates the NLRP3 inflammasome, pyroptotic and apoptotic caspases, and IL (interleukin)-1β transcription in human monocytes. Cellular Indexing of Transcriptomes and Epitopes by Sequencing revealed that components of the NLRP3 inflammasome and activation marker IL-1β dynamically vary with changes in salt loading/depletion. Mechanistically, we found that sodium-induced activation of the NLRP3 inflammasome is ENaC and IsoLG dependent. NLRP3 deficient mice develop a blunted hypertensive response to elevated sodium, and this is restored by the adoptive transfer of NLRP3 replete APCs. CONCLUSIONS These findings reveal a mechanistic link between ENaC, inflammation, and salt-sensitive hypertension involving NLRP3 inflammasome activation in APCs. APC activation via the NLRP3 inflammasome can serve as a potential diagnostic biomarker for salt sensitivity of blood pressure.
Collapse
Affiliation(s)
- Ashley Pitzer
- Department of Medicine, Division of Clinical Pharmacology, Vanderbilt University Medical Center Nashville, TN, USA
| | - Fernando Elijovich
- Department of Medicine, Division of Clinical Pharmacology, Vanderbilt University Medical Center Nashville, TN, USA
| | - Cheryl L. Laffer
- Department of Medicine, Division of Clinical Pharmacology, Vanderbilt University Medical Center Nashville, TN, USA
| | - Lale A. Ertuglu
- Department of Medicine, Division of Nephrology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Melis Sahinoz
- Department of Medicine, Division of Nephrology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Mohammad Saleem
- Department of Medicine, Division of Clinical Pharmacology, Vanderbilt University Medical Center Nashville, TN, USA
| | - Jaya Krishnan
- Department of Medicine, Division of Clinical Pharmacology, Vanderbilt University Medical Center Nashville, TN, USA
| | - Thanvi Dola
- Department of Medicine, Division of Clinical Pharmacology, Vanderbilt University Medical Center Nashville, TN, USA
| | - Luul A Aden
- Department of Medicine, Division of Clinical Pharmacology, Vanderbilt University Medical Center Nashville, TN, USA
| | - Quanhu Sheng
- Department of Biostatistics, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Michael A. Raddatz
- Medical Scientist Training Program, Vanderbilt University, Nashville, TN, USA
- Department of Medicine, University of California, Los Angeles, Los Angeles, CA, USA
| | - Celestine Wanjalla
- Department of Internal Medicine, Division of Infectious Diseases, Vanderbilt University Medical Center Nashville, TN, USA
| | - Suman Pakala
- Department of Internal Medicine, Division of Infectious Diseases, Vanderbilt University Medical Center Nashville, TN, USA
| | - Sean S Davies
- Department of Pharmacology, Vanderbilt University, Nashville, TN, USA
- Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN, USA
| | - David M Patrick
- Department of Medicine, Division of Clinical Pharmacology, Vanderbilt University Medical Center Nashville, TN, USA
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Department of Medicine, Division of Cardiovascular Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
| | | | - T. Alp Ikizler
- Department of Medicine, Division of Nephrology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Thomas Kleyman
- Departments of Medicine, Cell Biology, Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Annet Kirabo
- Department of Medicine, Division of Clinical Pharmacology, Vanderbilt University Medical Center Nashville, TN, USA
| |
Collapse
|
32
|
Deng W, Qi D, Tang XM, Deng XY, He J, Wang DX. THE WNK4/SPAK PATHWAY STIMULATES ALVEOLAR FLUID CLEARANCE BY UPREGULATION OF EPITHELIAL SODIUM CHANNEL IN MICE WITH LIPOPOLYSACCHARIDE-INDUCED ACUTE RESPIRATORY DISTRESS SYNDROME. Shock 2022; 58:68-77. [PMID: 35670456 PMCID: PMC9415224 DOI: 10.1097/shk.0000000000001945] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Revised: 03/01/2022] [Accepted: 04/15/2022] [Indexed: 11/25/2022]
Abstract
ABSTRACT With-No lysine Kinases (WNKs) have been newly implicated in alveolar fluid clearance (AFC). Epithelial sodium channels (ENaCs) serve a vital role in AFC. The potential protective effect of WNK4 in acute respiratory distress syndrome (ARDS), mediated by ENaC-associated AFC was investigated in the study. A model of lipopolysaccharide (LPS)-induced ARDS was established in C57BL/6 mice. WNK4, Sterile 20-related proline-alanine-rich kinase (SPAK), small interfering RNA (siRNA)-WNK4 or siRNA-SPAK were transfected into mouse lung or primary alveolar epithelial type II (ATII) cells. AFC, bronchoalveolar lavage fluid and lung histomorphology were determined. The expression of ENaC was determined to investigate the regulation of AFC by WNK4-SPAK signaling pathway. Activation of WNK4-SPAK signaling improved lung injury and survival rate, with enhanced AFC and reduced pulmonary edema via the upregulation of ENaC in ARDS. In primary rat ATII cells, gene-silencing by siRNA transfection reduced ENaC expression and the level of WNK4-associated SPAK phosphorylation. Immunoprecipitation revealed that the level of neural precursor cell-expressed developmentally downregulated gene 4 (Nedd4-2) binding to ENaC was decreased as a result of WNK4-SPAK signaling. The present study demonstrated that the WNK4/SPAK pathway improved AFC during LPS-induced ARDS, which is mainly dependent on the upregulation of ENaC with Nedd4-2-mediated ubiquitination.
Collapse
Affiliation(s)
- Wang Deng
- Department of Respiratory and Critical Care Medicine, Second Affiliated Hospital of Chongqing Medical University, Chongqing, China
- Chongqing Medical Research Center for Respiratory and Critical Care Medicine, Chongqing, China
| | - Di Qi
- Department of Respiratory and Critical Care Medicine, Second Affiliated Hospital of Chongqing Medical University, Chongqing, China
- Chongqing Medical Research Center for Respiratory and Critical Care Medicine, Chongqing, China
| | - Xu-Mao Tang
- Department of Respiratory and Critical Care Medicine, Second Affiliated Hospital of Chongqing Medical University, Chongqing, China
- Chongqing Medical Research Center for Respiratory and Critical Care Medicine, Chongqing, China
| | - Xin-Yu Deng
- Department of Respiratory and Critical Care Medicine, Second Affiliated Hospital of Chongqing Medical University, Chongqing, China
- Chongqing Medical Research Center for Respiratory and Critical Care Medicine, Chongqing, China
| | - Jing He
- Department of Respiratory and Critical Care Medicine, Second Affiliated Hospital of Chongqing Medical University, Chongqing, China
- Chongqing Medical Research Center for Respiratory and Critical Care Medicine, Chongqing, China
| | - Dao-Xin Wang
- Department of Respiratory and Critical Care Medicine, Second Affiliated Hospital of Chongqing Medical University, Chongqing, China
- Chongqing Medical Research Center for Respiratory and Critical Care Medicine, Chongqing, China
| |
Collapse
|
33
|
Veiras LC, Bernstein EA, Cao D, Okwan-Duodu D, Khan Z, Gibb DR, Roach A, Skelton R, Williams RM, Bernstein KE, Giani JF. Tubular IL-1β Induces Salt Sensitivity in Diabetes by Activating Renal Macrophages. Circ Res 2022; 131:59-73. [PMID: 35574842 PMCID: PMC9233055 DOI: 10.1161/circresaha.121.320239] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Chronic renal inflammation has been widely recognized as a major promoter of several forms of high blood pressure including salt-sensitive hypertension. In diabetes, IL (interleukin)-6 induces salt sensitivity through a dysregulation of the epithelial sodium channel. However, the origin of this inflammatory process and the molecular events that culminates with an abnormal regulation of epithelial sodium channel and salt sensitivity in diabetes are largely unknown. METHODS Both in vitro and in vivo approaches were used to investigate the molecular and cellular contributors to the renal inflammation associated with diabetic kidney disease and how these inflammatory components interact to develop salt sensitivity in db/db mice. RESULTS Thirty-four-week-old db/db mice display significantly higher levels of IL-1β in renal tubules compared with nondiabetic db/+ mice. Specific suppression of IL-1β in renal tubules prevented salt sensitivity in db/db mice. A primary culture of renal tubular epithelial cells from wild-type mice releases significant levels of IL-1β when exposed to a high glucose environment. Coculture of tubular epithelial cells and bone marrow-derived macrophages revealed that tubular epithelial cell-derived IL-1β promotes the polarization of macrophages towards a proinflammatory phenotype resulting in IL-6 secretion. To evaluate whether macrophages are the cellular target of IL-1β in vivo, diabetic db/db mice were transplanted with the bone marrow of IL-1R1 (IL-1 receptor type 1) knockout mice. db/db mice harboring an IL-1 receptor type 1 knockout bone marrow remained salt resistant, display lower renal inflammation and lower expression and activity of epithelial sodium channel compared with db/db transplanted with a wild-type bone marrow. CONCLUSIONS Renal tubular epithelial cell-derived IL-1β polarizes renal macrophages towards a proinflammatory phenotype that promotes salt sensitivity through the accumulation of renal IL-6. When tubular IL-1β synthesis is suppressed or in db/db mice in which immune cells lack the IL-1R1, macrophage polarization is blunted resulting in no salt-sensitive hypertension.
Collapse
Affiliation(s)
- Luciana C Veiras
- Department of Biomedical Sciences (L.C.V., E.A.B., D.C., Z.K., K.E.B., J.F.G.), Cedars-Sinai Medical Center, Los Angeles, CA
| | - Ellen A Bernstein
- Department of Biomedical Sciences (L.C.V., E.A.B., D.C., Z.K., K.E.B., J.F.G.), Cedars-Sinai Medical Center, Los Angeles, CA
| | - DuoYao Cao
- Department of Biomedical Sciences (L.C.V., E.A.B., D.C., Z.K., K.E.B., J.F.G.), Cedars-Sinai Medical Center, Los Angeles, CA
| | | | - Zakir Khan
- Department of Biomedical Sciences (L.C.V., E.A.B., D.C., Z.K., K.E.B., J.F.G.), Cedars-Sinai Medical Center, Los Angeles, CA
- Department of Pathology and Laboratory Medicine (Z.K., D.R.G., K.E.B., J.F.G.), Cedars-Sinai Medical Center, Los Angeles, CA
| | - David R Gibb
- Department of Pathology and Laboratory Medicine (Z.K., D.R.G., K.E.B., J.F.G.), Cedars-Sinai Medical Center, Los Angeles, CA
| | - Arantxa Roach
- Department of Biomedical Engineering, The City College of New York' New York' NY (A.R., R.S., R.M.W.)
| | - Rachel Skelton
- Department of Biomedical Engineering, The City College of New York' New York' NY (A.R., R.S., R.M.W.)
| | - Ryan M Williams
- Department of Biomedical Engineering, The City College of New York' New York' NY (A.R., R.S., R.M.W.)
| | - Kenneth E Bernstein
- Department of Biomedical Sciences (L.C.V., E.A.B., D.C., Z.K., K.E.B., J.F.G.), Cedars-Sinai Medical Center, Los Angeles, CA
- Department of Pathology and Laboratory Medicine (Z.K., D.R.G., K.E.B., J.F.G.), Cedars-Sinai Medical Center, Los Angeles, CA
| | - Jorge F Giani
- Department of Biomedical Sciences (L.C.V., E.A.B., D.C., Z.K., K.E.B., J.F.G.), Cedars-Sinai Medical Center, Los Angeles, CA
- Department of Pathology and Laboratory Medicine (Z.K., D.R.G., K.E.B., J.F.G.), Cedars-Sinai Medical Center, Los Angeles, CA
| |
Collapse
|
34
|
Mernea M, Ulăreanu RȘ, Cucu D, Al-Saedi JH, Pop CE, Fendrihan S, Anghelescu GDC, Mihăilescu DF. Epithelial Sodium Channel Inhibition by Amiloride Addressed with THz Spectroscopy and Molecular Modeling. Molecules 2022; 27:3271. [PMID: 35630748 PMCID: PMC9144217 DOI: 10.3390/molecules27103271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Revised: 05/08/2022] [Accepted: 05/18/2022] [Indexed: 11/16/2022] Open
Abstract
THz spectroscopy is important for the study of ion channels because it directly addresses the low frequency collective motions relevant for their function. Here we used THz spectroscopy to investigate the inhibition of the epithelial sodium channel (ENaC) by its specific blocker, amiloride. Experiments were performed on A6 cells' suspensions, which are cells overexpressing ENaC derived from Xenopus laevis kidney. THz spectra were investigated with or without amiloride. When ENaC was inhibited by amiloride, a substantial increase in THz absorption was noticed. Molecular modeling methods were used to explain the observed spectroscopic differences. THz spectra were simulated using the structural models of ENaC and ENaC-amiloride complexes built here. The agreement between the experiment and the simulations allowed us to validate the structural models and to describe the amiloride dynamics inside the channel pore. The amiloride binding site validated using THz spectroscopy agrees with previous mutagenesis studies. Altogether, our results show that THz spectroscopy can be successfully used to discriminate between native and inhibited ENaC channels and to characterize the dynamics of channels in the presence of their specific antagonist.
Collapse
Affiliation(s)
- Maria Mernea
- Department of Anatomy, Animal Physiology and Biophysics, Faculty of Biology, University of Bucharest, 91–95 Splaiul Independenței Str., 050095 Bucharest, Romania; (M.M.); (R.Ș.U.); (J.H.A.-S.); (G.D.C.A.); (D.F.M.)
| | - Roxana Ștefania Ulăreanu
- Department of Anatomy, Animal Physiology and Biophysics, Faculty of Biology, University of Bucharest, 91–95 Splaiul Independenței Str., 050095 Bucharest, Romania; (M.M.); (R.Ș.U.); (J.H.A.-S.); (G.D.C.A.); (D.F.M.)
| | - Dana Cucu
- Department of Anatomy, Animal Physiology and Biophysics, Faculty of Biology, University of Bucharest, 91–95 Splaiul Independenței Str., 050095 Bucharest, Romania; (M.M.); (R.Ș.U.); (J.H.A.-S.); (G.D.C.A.); (D.F.M.)
| | - Jasim Hafedh Al-Saedi
- Department of Anatomy, Animal Physiology and Biophysics, Faculty of Biology, University of Bucharest, 91–95 Splaiul Independenței Str., 050095 Bucharest, Romania; (M.M.); (R.Ș.U.); (J.H.A.-S.); (G.D.C.A.); (D.F.M.)
| | - Cristian-Emilian Pop
- Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Bucharest, 91–95 Splaiul Independenței Str., 050095 Bucharest, Romania;
- Non-Governmental Research Organization Biologic, 14 Schitului Str., 032044 Bucharest, Romania;
| | - Sergiu Fendrihan
- Non-Governmental Research Organization Biologic, 14 Schitului Str., 032044 Bucharest, Romania;
- Faculty of Medicine, University “Vasile Goldis”, Bulevardul Revoluției 94, 310025 Arad, Romania
| | - Giorgiana Diana Carmen Anghelescu
- Department of Anatomy, Animal Physiology and Biophysics, Faculty of Biology, University of Bucharest, 91–95 Splaiul Independenței Str., 050095 Bucharest, Romania; (M.M.); (R.Ș.U.); (J.H.A.-S.); (G.D.C.A.); (D.F.M.)
| | - Dan Florin Mihăilescu
- Department of Anatomy, Animal Physiology and Biophysics, Faculty of Biology, University of Bucharest, 91–95 Splaiul Independenței Str., 050095 Bucharest, Romania; (M.M.); (R.Ș.U.); (J.H.A.-S.); (G.D.C.A.); (D.F.M.)
- Biometric Psychiatric Genetics Research Unit, Alexandru Obregia Psychiatric Hospital, 10 Șoseaua Berceni Str., 041914 Bucharest, Romania
| |
Collapse
|
35
|
Hua Y, Han A, Yu T, Hou Y, Ding Y, Nie H. Small Extracellular Vesicles Containing miR-34c Derived from Bone Marrow Mesenchymal Stem Cells Regulates Epithelial Sodium Channel via Targeting MARCKS. Int J Mol Sci 2022; 23:ijms23095196. [PMID: 35563590 PMCID: PMC9101277 DOI: 10.3390/ijms23095196] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Revised: 04/29/2022] [Accepted: 05/04/2022] [Indexed: 12/18/2022] Open
Abstract
Epithelial sodium channel (ENaC) is a pivotal regulator of alveolar fluid clearance in the airway epithelium and plays a key role in the treatment of acute lung injury (ALI), which is mainly composed of the three homologous subunits (α, β and γ). The mechanisms of microRNAs in small extracellular vesicles (sEVs) derived from mesenchymal stem cell (MSC-sEVs) on the regulation of lung ion transport are seldom reported. In this study, we aimed at investigating whether miR-34c had an effect on ENaC dysfunction induced by lipopolysaccharide and explored the underlying mechanism in this process. Primarily, the effect of miR-34c on lung edema and histopathology changes in an ALI mouse model was investigated. Then the uptake of PKH26-labeled sEVs was observed in recipient cells, and we observed that the overexpression of miR-34c in MSC-sEVs could upregulate the LPS-inhibited γ-ENaC expression. The dual luciferase reporter gene assay demonstrated that myristoylated alanine-rich C kinase substrate (MARCKS) was one of target genes of miR-34c, the protein expression of which was negatively correlated with miR-34c. Subsequently, either upregulating miR-34c or knocking down MARCKS could increase the protein expression of phospho-phosphatidylinositol 3-kinase (p-PI3K) and phospho-protein kinase B (p-AKT), implying a downstream regulation pathway was involved. All of the above suggest that miR-34c in MSC-sEVs can attenuate edematous lung injury via enhancing γ-ENaC expression, at least partially, through targeting MARCKS and activating the PI3K/AKT signaling pathway subsequently.
Collapse
|
36
|
Zhang L, Wang X, Chen J, Kleyman TR, Sheng S. Accessibility of ENaC extracellular domain central core residues. J Biol Chem 2022; 298:101860. [PMID: 35339489 PMCID: PMC9052164 DOI: 10.1016/j.jbc.2022.101860] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Revised: 03/16/2022] [Accepted: 03/21/2022] [Indexed: 11/20/2022] Open
Abstract
The epithelial Na+ channel (ENaC)/degenerin family has a similar extracellular architecture, where specific regulatory factors interact and alter channel gating behavior. The extracellular palm domain serves as a key link to the channel pore. In this study, we used cysteine-scanning mutagenesis to assess the functional effects of Cys-modifying reagents on palm domain β10 strand residues in mouse ENaC. Of the 13 ENaC α subunit mutants with Cys substitutions examined, only mutants at sites in the proximal region of β10 exhibited changes in channel activity in response to methanethiosulfonate reagents. Additionally, Cys substitutions at three proximal sites of β and γ subunit β10 strands also rendered mutant channels methanethiosulfonate-responsive. Moreover, multiple Cys mutants were activated by low concentrations of thiophilic Cd2+. Using the Na+ self-inhibition response to assess ENaC gating behavior, we identified four α, two β, and two γ subunit β10 strand mutations that changed the Na+ self-inhibition response. Our results suggest that the proximal regions of β10 strands in all three subunits are accessible to small aqueous compounds and Cd2+ and have a role in modulating ENaC gating. These results are consistent with a structural model of mouse ENaC that predicts the presence of aqueous tunnels adjacent to the proximal part of β10 and with previously resolved structures of a related family member where palm domain structural transitions were observed with channels in an open or closed state.
Collapse
Affiliation(s)
- Lei Zhang
- Departments of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA; Department of Nephrology, Hunan Key Laboratory of Kidney Disease and Blood Purification, The Second Xiangya Hospital, Central South University, Changsha, Hunan, China; The Third Xiangya Hospital of Central South University, Changsha, Hunan, China
| | - Xueqi Wang
- Departments of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA; Department of Nephrology, Hunan Key Laboratory of Kidney Disease and Blood Purification, The Second Xiangya Hospital, Central South University, Changsha, Hunan, China; The Third Xiangya Hospital of Central South University, Changsha, Hunan, China
| | - Jingxin Chen
- Departments of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Thomas R Kleyman
- Departments of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA; Cell Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA; Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.
| | - Shaohu Sheng
- Departments of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| |
Collapse
|
37
|
Kota P. Sustained inhibition of ENaC in CF: Potential RNA-based therapies for mutation-agnostic treatment. Curr Opin Pharmacol 2022; 64:102209. [PMID: 35483215 DOI: 10.1016/j.coph.2022.102209] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Revised: 02/26/2022] [Accepted: 03/02/2022] [Indexed: 12/17/2022]
Abstract
Disruption of the equilibrium between ion secretion and absorption processes by the airway epithelium is central to many muco-obstructive lung diseases including cystic fibrosis (CF). Besides correction of defective folding and function of CFTR, inhibition of amiloride-sensitive epithelia sodium channels (ENaC) has emerged as a bona fide therapeutic strategy to improve mucociliary clearance in patients with CF. The short half-life of amiloride-based ENaC blockers and hyperosmotic therapies have led to the development of novel RNA-based interventions for targeted and sustained reduction of ENaC expression and function in preclinical models of CF. This review summarizes the recent advances in RNA therapeutics targeting ENaC for mutation-agnostic treatment of CF.
Collapse
Affiliation(s)
- Pradeep Kota
- Cystic Fibrosis Research and Treatment Center, University of North Carolina at Chapel Hill, NC 27599, USA.
| |
Collapse
|
38
|
Essigke D, Bohnert BN, Janessa A, Wörn M, Omage K, Kalbacher H, Birkenfeld AL, Bugge TH, Szabo R, Artunc F. Sodium retention in nephrotic syndrome is independent of the activation of the membrane-anchored serine protease prostasin (CAP1/PRSS8) and its enzymatic activity. Pflugers Arch 2022; 474:613-624. [PMID: 35312839 PMCID: PMC9117342 DOI: 10.1007/s00424-022-02682-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Revised: 02/25/2022] [Accepted: 03/04/2022] [Indexed: 12/11/2022]
Abstract
Experimental nephrotic syndrome leads to activation of the epithelial sodium channel (ENaC) by proteolysis and promotes renal sodium retention. The membrane-anchored serine protease prostasin (CAP1/PRSS8) is expressed in the distal nephron and participates in proteolytic ENaC regulation by serving as a scaffold for other serine proteases. However, it is unknown whether prostasin is also involved in ENaC-mediated sodium retention of experimental nephrotic syndrome. In this study, we used genetically modified knock-in mice with Prss8 mutations abolishing its proteolytic activity (Prss8-S238A) or prostasin activation (Prss8-R44Q) to investigate the development of sodium retention in doxorubicin-induced nephrotic syndrome. Healthy Prss8-S238A and Prss8-R44Q mice had normal ENaC activity as reflected by the natriuretic response to the ENaC blocker triamterene. After doxorubicin injection, all genotypes developed similar proteinuria. In all genotypes, urinary prostasin excretion increased while renal expression was not altered. In nephrotic mice of all genotypes, triamterene response was similarly increased, consistent with ENaC activation. As a consequence, urinary sodium excretion dropped in all genotypes and mice similarly gained body weight by + 25 ± 3% in Prss8-wt, + 20 ± 2% in Prss8-S238A and + 28 ± 3% in Prss8-R44Q mice (p = 0.16). In Western blots, expression of fully cleaved α- and γ-ENaC was similarly increased in nephrotic mice of all genotypes. In conclusion, proteolytic ENaC activation and sodium retention in experimental nephrotic syndrome are independent of the activation of prostasin and its enzymatic activity and are consistent with the action of aberrantly filtered serine proteases or proteasuria.
Collapse
Affiliation(s)
- Daniel Essigke
- Division of Endocrinology, Diabetology and Nephrology, Department of Internal Medicine, University Hospital Tübingen, Otfried-Mueller-Str.10, 72076, Tuebingen, Germany
- Institute of Diabetes Research and Metabolic Diseases (IDM) of the Helmholtz Center Munich at the University Tübingen, Tuebingen, Germany
- German Center for Diabetes Research (DZD) at the University Tübingen, Tuebingen, Germany
| | - Bernhard N Bohnert
- Division of Endocrinology, Diabetology and Nephrology, Department of Internal Medicine, University Hospital Tübingen, Otfried-Mueller-Str.10, 72076, Tuebingen, Germany
- Institute of Diabetes Research and Metabolic Diseases (IDM) of the Helmholtz Center Munich at the University Tübingen, Tuebingen, Germany
- German Center for Diabetes Research (DZD) at the University Tübingen, Tuebingen, Germany
| | - Andrea Janessa
- Division of Endocrinology, Diabetology and Nephrology, Department of Internal Medicine, University Hospital Tübingen, Otfried-Mueller-Str.10, 72076, Tuebingen, Germany
| | - Matthias Wörn
- Division of Endocrinology, Diabetology and Nephrology, Department of Internal Medicine, University Hospital Tübingen, Otfried-Mueller-Str.10, 72076, Tuebingen, Germany
| | - Kingsley Omage
- Division of Endocrinology, Diabetology and Nephrology, Department of Internal Medicine, University Hospital Tübingen, Otfried-Mueller-Str.10, 72076, Tuebingen, Germany
| | | | - Andreas L Birkenfeld
- Division of Endocrinology, Diabetology and Nephrology, Department of Internal Medicine, University Hospital Tübingen, Otfried-Mueller-Str.10, 72076, Tuebingen, Germany
- Institute of Diabetes Research and Metabolic Diseases (IDM) of the Helmholtz Center Munich at the University Tübingen, Tuebingen, Germany
- German Center for Diabetes Research (DZD) at the University Tübingen, Tuebingen, Germany
| | - Thomas H Bugge
- Proteases and Tissue Remodeling Section, NIDCR, National Institutes of Health, Bethesda, MD, USA
| | - Roman Szabo
- Proteases and Tissue Remodeling Section, NIDCR, National Institutes of Health, Bethesda, MD, USA
| | - Ferruh Artunc
- Division of Endocrinology, Diabetology and Nephrology, Department of Internal Medicine, University Hospital Tübingen, Otfried-Mueller-Str.10, 72076, Tuebingen, Germany.
- Institute of Diabetes Research and Metabolic Diseases (IDM) of the Helmholtz Center Munich at the University Tübingen, Tuebingen, Germany.
- German Center for Diabetes Research (DZD) at the University Tübingen, Tuebingen, Germany.
| |
Collapse
|
39
|
Al‐Qusairi L, Basquin D, Stifanelli M, Welling PA, Staub O. Does the early aldosterone-induced SGK1 play a role in early Kaliuresis? Physiol Rep 2022; 10:e15188. [PMID: 35224872 PMCID: PMC8883148 DOI: 10.14814/phy2.15188] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Revised: 12/30/2021] [Accepted: 12/30/2021] [Indexed: 06/14/2023] Open
Abstract
Urinary K+ potassium excretion rapidly increases after a potassium-rich meal. The early aldosterone-induced sgk1 gene (encoding serum and glucocorticoid-induced kinase 1), activates potassium clearance, but the role of this kinase in the early activation of K+ secretion has not been clearly defined. Here, we challenged inducible renal-tubule-specific Sgk1Pax8 / LC1 knockout mice with an acute high-potassium load (HK:5%K+ ) and compared the physiological and molecular responses to control mice. We observe that urinary excretion after a K+ load over the first 3 h is not dependent on SGK1 but is coincident with the rapid dephosphorylation of the Na+ ,Cl- -cotransporter (NCC) to increase distal salt delivery. Molecular analyses indicate that whereas SGK1-mediated phosphorylation of the ubiquitin-protein ligase NEDD4-2 begins to increase by 3h, SGK1-dependent proteolytic activation of ENaC only becomes detectable after 6 h of HK intake. Consistent with SGK1-dependent ENaC activation via inhibition of NEDD4-2-mediated ubiquitylation, Sgk1Pax8 / LC1 mice are unable to efficiently inhibit NEDD4-2 or increase ENaC cleavage after 6 h of HK. Nevertheless, no defect in acute K+ balance was detected in the mutant mice after 6 h of HK. Moreover, we found that Sgk1Pax8 / LC1 mice reduce NCC phosphorylation and NCC-mediated salt absorption to a greater extent than control mice after a K+ load, promoting increased amiloride-sensitive Na+ -reabsorption via ENaC to maintain adequate kaliuresis. Together, these data indicate that: (a) during the early 3 h of HK intake, K+ excretion is SGK1-independent even under an extreme K+ challenge, (b) shortly after, SGK1 inhibits NEDD4-2 and activates ENaC to stimulate K+ -secretion, (c) SGK1-dependent phosphorylation of NCC occurs, acting more likely as a brake pedal to prevent excessive K+ loss.
Collapse
Affiliation(s)
- Lama Al‐Qusairi
- Division of NephrologyJohns Hopkins University School of MedicineBaltimoreUSA
- Department of Biomedical SciencesUniversity of LausanneLausanneSwitzerland
| | - Denis Basquin
- Department of PhysiologyUniversity of MarylandBaltimoreUSA
- Department of Biomedical SciencesUniversity of LausanneLausanneSwitzerland
| | - Matteo Stifanelli
- Department of Biomedical SciencesUniversity of LausanneLausanneSwitzerland
| | - Paul A. Welling
- Division of NephrologyJohns Hopkins University School of MedicineBaltimoreUSA
| | - Olivier Staub
- Department of Biomedical SciencesUniversity of LausanneLausanneSwitzerland
| |
Collapse
|
40
|
Kelchtermans J, Pinney SE, Leonard JMM, Mcgrath-Morrow S. Diagnostic and management considerations in pseudohypoaldosteronism type 1b. BMJ Case Rep 2022; 15:e246538. [PMID: 34980640 PMCID: PMC8724702 DOI: 10.1136/bcr-2021-246538] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/16/2021] [Indexed: 11/04/2022] Open
Abstract
Pseudohypoaldosteronism type 1B is a rare autosomal recessive disorder caused by dysfunction of amiloride-sensitive epithelial sodium channels (ENaCs). We present the case of a neonate with cardiogenic shock after cardiac arrest due to profound hyperkalaemia. Genetic testing revealed a novel homozygous variant in SCNNIA We review diagnostic considerations including the molecular mechanisms of disease, discuss treatment approaches and highlight the possible significance of the diversity of pulmonary ENaCs.
Collapse
Affiliation(s)
- Jelte Kelchtermans
- Division of Pulmonary and Sleep Medicine, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Sara E Pinney
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Division of Endocrinology and Diabetes, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Jacqueline M M Leonard
- Roberts Individualized Medical Genetics Center, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Sharon Mcgrath-Morrow
- Division of Pulmonary and Sleep Medicine, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| |
Collapse
|
41
|
Ray EC, Pitzer A, Lam T, Jordahl A, Patel R, Ao M, Marciszyn A, Winfrey A, Barak Y, Sheng S, Kirabo A, Kleyman TR. Salt sensitivity of volume and blood pressure in a mouse with globally reduced ENaC γ-subunit expression. Am J Physiol Renal Physiol 2021; 321:F705-F714. [PMID: 34632813 PMCID: PMC8714976 DOI: 10.1152/ajprenal.00559.2020] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Revised: 09/14/2021] [Accepted: 10/04/2021] [Indexed: 12/15/2022] Open
Abstract
The epithelial Na+ channel (ENaC) promotes the absorption of Na+ in the aldosterone-sensitive distal nephron, colon, and respiratory epithelia. Deletion of genes encoding subunits of ENaC results in early postnatal mortality. Here, we present the initial characterization of a mouse with dramatically suppressed expression of the ENaC γ-subunit. We used this hypomorphic (γmt) allele to explore the importance of this subunit in homeostasis of electrolytes and body fluid volume. At baseline, γ-subunit expression in γmt/mt mice was markedly suppressed in the kidney and lung, whereas electrolytes resembled those of littermate controls. Aldosterone levels in γmt/mt mice exceeded those seen in littermate controls. Quantitative magnetic resonance measurement of body composition revealed similar baseline body water, lean tissue mass, and fat tissue mass in γmt/mt mice and controls. γmt/mt mice exhibited a more rapid decline in body water and lean tissue mass in response to a low-Na+ diet than the controls. Replacement of drinking water with 2% saline selectively and transiently increased body water and lean tissue mass in γmt/mt mice relative to the controls. Lower blood pressures were variably observed in γmt/mt mice on a high-salt diet compared with the controls. γmt/mt also exhibited reduced diurnal blood pressure variation, a "nondipping" phenotype, on a high-Na+ diet. Although ENaC in the renal tubules and colon works to prevent extracellular fluid volume depletion, our observations suggest that ENaC in other tissues may participate in regulating extracellular fluid volume and blood pressure.NEW & NOTEWORTHY A mouse with globally suppressed expression of the epithelial Na+ channel γ-subunit showed enhanced sensitivity to dietary salt, including a transient increase in total body fluid, reduced blood pressure, and reduced diurnal blood pressure variation when given a dietary NaCl challenge. These results point to a role for the epithelial Na+ channel in regulating body fluid and blood pressure beyond classical transepithelial Na+ transport mechanisms.
Collapse
Affiliation(s)
- Evan C Ray
- Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Ashley Pitzer
- Department of Medicine, Vanderbilt University, Nashville, Tennessee
| | - Tracey Lam
- Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Alexa Jordahl
- Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Ritam Patel
- Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Mingfang Ao
- Department of Medicine, Vanderbilt University, Nashville, Tennessee
| | - Allison Marciszyn
- Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Aaliyah Winfrey
- Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Yaacov Barak
- Department of Obstetrics, Gynecology, and Reproductive Sciences, University of Pittsburgh, Magee-Womens Research Institute, Pittsburgh, Pennsylvania
| | - Shaohu Sheng
- Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Annet Kirabo
- Department of Medicine, Vanderbilt University, Nashville, Tennessee
| | - Thomas R Kleyman
- Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
- Department of Cell Biology, University of Pittsburgh, Pittsburgh, Pennsylvania
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, Pennsylvania
| |
Collapse
|
42
|
Nemeth Z, Ryan MJ, Granger JP, Drummond HA. Expression of Exogenous Epithelial Sodium Channel Beta Subunit in the Mouse Middle Cerebral Artery Increases Pressure-Induced Constriction. Am J Hypertens 2021; 34:1227-1235. [PMID: 34161569 PMCID: PMC9526803 DOI: 10.1093/ajh/hpab098] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Accepted: 06/18/2021] [Indexed: 01/27/2023] Open
Abstract
BACKGROUND Pressure-induced constriction (PIC) is inherent to small arteries and arterioles, in which intraluminal pressure-induced vascular smooth muscle cell stretch elicits vasoconstriction. Degenerin (Deg) proteins, such as beta-epithelial Na+ channel (βENaC), have been studied in the PIC response because they are evolutionarily linked to known mechanosensors. While loss of Deg function phenotypes are plentiful, a gain-of-function phenotype has not been studied. The aim of this study was to determine if expression of exogenous βENaC in the isolated middle cerebral artery (MCA) enhances the PIC response. METHODS Isolated MCA segments from female mice (24 weeks, n = 5) were transfected with enhanced green fluorescent protein-βENaC (EGFP-βENaC) or with EGFP alone, incubated overnight at 37 °C, then studied in a pressure myograph. RESULTS Mechanical/morphological properties and vasoconstrictor responses to KCl and phenylephrine were identical in EGFP-βENaC and EGFP MCAs. In contrast, PIC responses were greater in EGFP-βENaC segments with ~2-fold greater peak myogenic tone. CONCLUSIONS These data confirm previous findings that βENaC is critical in the PIC response. These data provide proof-of-concept that upregulating βENaC can enhance PIC responses and lay the foundation to test the hypothesis that inflammation-mediated downregulation of βENaC contributes to cerebrovascular dysfunction.
Collapse
Affiliation(s)
- Zoltan Nemeth
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, Mississippi, USA
| | - Michael J Ryan
- Department of Pharmacology, Physiology and Neuroscience, University of South Carolina School of Medicine, Columbia, South Carolina, USA
| | - Joey P Granger
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, Mississippi, USA
| | - Heather A Drummond
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, Mississippi, USA
| |
Collapse
|
43
|
Chang J, Hu X, Nan J, Zhang X, Jin X. HOXD9‑induced SCNN1A upregulation promotes pancreatic cancer cell proliferation, migration and predicts prognosis by regulating epithelial‑mesenchymal transformation. Mol Med Rep 2021; 24:819. [PMID: 34558641 PMCID: PMC8477178 DOI: 10.3892/mmr.2021.12459] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Accepted: 05/24/2021] [Indexed: 12/13/2022] Open
Abstract
Pancreatic cancer (PC) is a malignant tumor disease, whose molecular mechanism is not fully understood. Sodium channel epithelial 1α subunit (SCNN1A) serves an important role in tumor progression. The current study explored the role of homeobox D9 (HOXD9) and SCNN1A in the progression of PC. The expression of SCNN1A and HOXD9 in PC samples was predicted on online databases and detected in PC cell lines. The association between SCNN1A expression and PC prognosis was examined by the Gene Expression Profiling Interactive Analysis, The Cancer Genome Atlas and Genotype‑Tissue Expression databases and by a Kaplan‑Meier plotter. Subsequently, the biological effects of SCNN1A on PC cell growth, colony formation, migration and invasion were investigated through RNA interference and cell transfection. Next, the expression of E‑cadherin, N‑cadherin, Vimentin and Snail was detected by western blotting to discover whether HOXD9 dysregulation mediated PC metastasis. Binding sites of HOXD9 and SCNN1A promoters were predicted on JASPAR. Reverse transcription‑quantitative PCR and western blotting were used to detect the expression level of SCNN1A following interference and overexpression of HOXD9. Luciferase assay detected luciferase activity following interference with HOXD9 and the transcriptional activity of SCNN1A following binding site deletion. High expression of SCNN1A and HOXD9 in PC was predicted by online databases, signifying poor prognosis. The present study confirmed the above predictions in PC cell lines. Knockdown of SCNN1A and HOXD9 could effectively inhibit the proliferation, migration, invasion and epithelial‑mesenchymal transition of PC cells. Furthermore, HOXD9 activated SCNN1A transcription, forming a feedback regulatory loop. HOXD9 was demonstrated to activate SCNN1A and promote the malignant biological process of PC.
Collapse
Affiliation(s)
- Jinhai Chang
- Department of Internal Medicine, Yanbian Hospital of Traditional Chinese Medicine, Yanbian, Jilin 133000, P.R. China
| | - Xuguang Hu
- Department of Hepatobiliary Surgery, Jiangxi Cancer Hospital, Nanchang, Jiangxi 330029, P.R. China
| | - Jinniang Nan
- Department of Clinical Medicine, Jiangxi Health Vocational College of China, Nanchang, Jiangxi 330052, P.R. China
- Correspondence to: Dr Jinniang Nan, Department of Clinical Medicine, Jiangxi Health Vocational College of China, 689 Huiren Avenue, Xiaolan Economic Development Zone, Nanchang, Jiangxi 330052, P.R. China, E-mail:
| | - Xianghua Zhang
- Department of Thoracic Oncology, Jilin Province Cancer Hospital, Changchun, Jilin 130000, P.R. China
| | - Xintian Jin
- Department of Thoracic Surgery, Jilin Province Cancer Hospital, Changchun, Jilin 130000, P.R. China
| |
Collapse
|
44
|
Hiramatsu A, Izumi Y, Eguchi K, Matsuo N, Deng Q, Inoue H, Nakayama Y, Nonoguchi H, Aramburu J, López-Rodríguez C, Kakizoe Y, Adachi M, Kuwabara T, Kim-Mitsuyama S, Mukoyama M. Salt-Sensitive Hypertension of the Renal Tubular Cell-Specific NFAT5 (Nuclear Factor of Activated T-Cells 5) Knockout Mice. Hypertension 2021; 78:1335-1346. [PMID: 34601973 DOI: 10.1161/hypertensionaha.121.17435] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
[Figure: see text].
Collapse
Affiliation(s)
- Akiko Hiramatsu
- Department of Nephrology (A.H., Y.I., K.E., N.M., Q.D., H.I., Y.N., Y.K., M.A., T.K., M.M.), Kumamoto University Graduate School of Medical Sciences, Japan
| | - Yuichiro Izumi
- Department of Nephrology (A.H., Y.I., K.E., N.M., Q.D., H.I., Y.N., Y.K., M.A., T.K., M.M.), Kumamoto University Graduate School of Medical Sciences, Japan
| | - Koji Eguchi
- Department of Nephrology (A.H., Y.I., K.E., N.M., Q.D., H.I., Y.N., Y.K., M.A., T.K., M.M.), Kumamoto University Graduate School of Medical Sciences, Japan
| | - Naomi Matsuo
- Department of Nephrology (A.H., Y.I., K.E., N.M., Q.D., H.I., Y.N., Y.K., M.A., T.K., M.M.), Kumamoto University Graduate School of Medical Sciences, Japan
| | - Qinyuan Deng
- Department of Nephrology (A.H., Y.I., K.E., N.M., Q.D., H.I., Y.N., Y.K., M.A., T.K., M.M.), Kumamoto University Graduate School of Medical Sciences, Japan
| | - Hideki Inoue
- Department of Nephrology (A.H., Y.I., K.E., N.M., Q.D., H.I., Y.N., Y.K., M.A., T.K., M.M.), Kumamoto University Graduate School of Medical Sciences, Japan
| | - Yushi Nakayama
- Department of Nephrology (A.H., Y.I., K.E., N.M., Q.D., H.I., Y.N., Y.K., M.A., T.K., M.M.), Kumamoto University Graduate School of Medical Sciences, Japan
| | - Hiroshi Nonoguchi
- Division of Internal Medicine, Kitasato University Medical Center, Kitamoto, Saitama, Japan (H.N.)
| | - Jose Aramburu
- Immunology Unit, Department of Experimental and Health Sciences, Universitat Pompeu Fabra, and Barcelona Biomedical Research Park, Spain (J.A., C.L.-R.)
| | - Cristina López-Rodríguez
- Immunology Unit, Department of Experimental and Health Sciences, Universitat Pompeu Fabra, and Barcelona Biomedical Research Park, Spain (J.A., C.L.-R.)
| | - Yutaka Kakizoe
- Department of Nephrology (A.H., Y.I., K.E., N.M., Q.D., H.I., Y.N., Y.K., M.A., T.K., M.M.), Kumamoto University Graduate School of Medical Sciences, Japan
| | - Masataka Adachi
- Department of Nephrology (A.H., Y.I., K.E., N.M., Q.D., H.I., Y.N., Y.K., M.A., T.K., M.M.), Kumamoto University Graduate School of Medical Sciences, Japan
| | - Takashige Kuwabara
- Department of Nephrology (A.H., Y.I., K.E., N.M., Q.D., H.I., Y.N., Y.K., M.A., T.K., M.M.), Kumamoto University Graduate School of Medical Sciences, Japan
| | - Shokei Kim-Mitsuyama
- Department of Pharmacology and Molecular Therapeutics (S.K.-M.), Kumamoto University Graduate School of Medical Sciences, Japan
| | - Masashi Mukoyama
- Department of Nephrology (A.H., Y.I., K.E., N.M., Q.D., H.I., Y.N., Y.K., M.A., T.K., M.M.), Kumamoto University Graduate School of Medical Sciences, Japan
| |
Collapse
|
45
|
Vallée C, Howlin B, Lewis R. Ion Selectivity in the ENaC/DEG Family: A Systematic Review with Supporting Analysis. Int J Mol Sci 2021; 22:ijms222010998. [PMID: 34681656 PMCID: PMC8536179 DOI: 10.3390/ijms222010998] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Revised: 10/01/2021] [Accepted: 10/05/2021] [Indexed: 12/16/2022] Open
Abstract
The Epithelial Sodium Channel/Degenerin (ENaC/DEG) family is a superfamily of sodium-selective channels that play diverse and important physiological roles in a wide variety of animal species. Despite their differences, they share a high homology in the pore region in which the ion discrimination takes place. Although ion selectivity has been studied for decades, the mechanisms underlying this selectivity for trimeric channels, and particularly for the ENaC/DEG family, are still poorly understood. This systematic review follows PRISMA guidelines and aims to determine the main components that govern ion selectivity in the ENaC/DEG family. In total, 27 papers from three online databases were included according to specific exclusion and inclusion criteria. It was found that the G/SxS selectivity filter (glycine/serine, non-conserved residue, serine) and other well conserved residues play a crucial role in ion selectivity. Depending on the ion type, residues with different properties are involved in ion permeability. For lithium against sodium, aromatic residues upstream of the selectivity filter seem to be important, whereas for sodium against potassium, negatively charged residues downstream of the selectivity filter seem to be important. This review provides new perspectives for further studies to unravel the mechanisms of ion selectivity.
Collapse
Affiliation(s)
- Cédric Vallée
- Leverhulme Quantum Biology Doctoral Training Centre, University of Surrey, Guildford GU2 5XH, UK; (C.V.); (B.H.)
- Department of Chemistry, Faculty of Engineering and Physical Sciences, University of Surrey, Guildford GU2 7XH, UK
- School of Veterinary Medicine, Faculty of Health and Medical Sciences, University of Surrey, Guildford GU2 7AL, UK
| | - Brendan Howlin
- Leverhulme Quantum Biology Doctoral Training Centre, University of Surrey, Guildford GU2 5XH, UK; (C.V.); (B.H.)
- Department of Chemistry, Faculty of Engineering and Physical Sciences, University of Surrey, Guildford GU2 7XH, UK
| | - Rebecca Lewis
- Leverhulme Quantum Biology Doctoral Training Centre, University of Surrey, Guildford GU2 5XH, UK; (C.V.); (B.H.)
- School of Veterinary Medicine, Faculty of Health and Medical Sciences, University of Surrey, Guildford GU2 7AL, UK
- Correspondence:
| |
Collapse
|
46
|
Mutchler SM, Hasan M, Kohan DE, Kleyman TR, Tan RJ. Deletion of the Gamma Subunit of ENaC in Endothelial Cells Does Not Protect against Renal Ischemia Reperfusion Injury. Int J Mol Sci 2021; 22:ijms222010914. [PMID: 34681576 PMCID: PMC8535410 DOI: 10.3390/ijms222010914] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Revised: 10/01/2021] [Accepted: 10/04/2021] [Indexed: 11/16/2022] Open
Abstract
Acute kidney injury due to renal ischemia-reperfusion injury (IRI) may lead to chronic or end stage kidney disease. A greater understanding of the cellular mechanisms underlying IRI are required to develop therapeutic options aimed at limiting or reversing damage from IRI. Prior work has shown that deletion of the α subunit of the epithelial Na+ channel (ENaC) in endothelial cells protects from IRI by increasing the availability of nitric oxide. While canonical ENaCs consist of an α, β, and γ subunit, there is evidence of non-canonical ENaC expression in endothelial cells involving the α subunit. We therefore tested whether the deletion of the γ subunit of ENaC also protects mice from IRI to differentiate between these channel configurations. Mice with endothelial-specific deletion of the γ subunit and control littermates were subjected to unilateral renal artery occlusion followed by 48 h of reperfusion. No significant difference was noted in injury between the two groups as assessed by serum creatinine and blood urea nitrogen, levels of specific kidney injury markers, and histological examination. While deletion of the γ subunit did not alter infiltration of immune cells or cytokine message, it was associated with an increase in levels of total and phosphorylated endothelial nitric oxide synthase (eNOS) in the injured kidneys. Our studies demonstrate that even though deletion of the γ subunit of ENaC may allow for greater activation of eNOS, this is not sufficient to prevent IRI, suggesting the protective effects of α subunit deletion may be due, in part, to other mechanisms.
Collapse
Affiliation(s)
- Stephanie M. Mutchler
- Department of Medicine, University of Pittsburgh, Pittsburgh, PA 15261, USA; (S.M.M.); (R.J.T.)
| | - Mahpara Hasan
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213, USA;
| | - Donald E. Kohan
- Department of Medicine, University of Utah, Salt Lake City, UT 84112, USA;
| | - Thomas R. Kleyman
- Departments of Medicine, Cell Biology, and Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA 15261, USA
- Correspondence:
| | - Roderick J. Tan
- Department of Medicine, University of Pittsburgh, Pittsburgh, PA 15261, USA; (S.M.M.); (R.J.T.)
| |
Collapse
|
47
|
Wang H, Huang L, Chen L, Ji J, Zheng Y, Wang Z. Identification of Novel Biomarkers Related to Lung Squamous Cell Carcinoma Using Integrated Bioinformatics Analysis. Comput Math Methods Med 2021; 2021:9059116. [PMID: 34659450 PMCID: PMC8519687 DOI: 10.1155/2021/9059116] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Accepted: 09/18/2021] [Indexed: 11/18/2022]
Abstract
BACKGROUND Lung squamous cell carcinoma (LUSC) is one of the most common types of lung carcinoma and has specific clinicopathologic characteristics. In this study, we screened novel molecular biomarkers relevant to the prognosis of LUSC to explore new diagnostic and treatment approaches for this disease. METHODS We downloaded GSE73402 from the Gene Expression Omnibus (GEO) database. GSE73402 contains 62 samples, which could be classified as four subtypes according to their pathology and stages. Via weighted gene coexpression network analysis (WGCNA), the main module was identified and was further analyzed using differentially expressed genes (DEGs) analysis. Then, by protein-protein interaction (PPI) network and Gene Expression Profiling Interactive Analysis (GEPIA), hub genes were screened for potential biomarkers of LUSC. RESULTS Via WGCNA, the yellow module containing 349 genes was identified, and it is strongly related to the subtype of CIS (carcinoma in situ). DEGs analysis detected 180 genes that expressed differentially between the subtype of CIS and subtype of early-stage carcinoma (Stage I and Stage II). A PPI network of DEGs was constructed, and the top 20 genes with the highest correlations were selected for GEPIA database to explore their effect on LUSC survival prognosis. Finally, ITGA5, TUBB3, SCNN1B, and SERPINE1 were screened as hub genes in LUSC. CONCLUSIONS ITGA5, TUBB3, SCNN1B, and SERPINE1 may have great diagnostic and prognostic significance for LUSC and have great potential to be new treatment targets for LUSC.
Collapse
Affiliation(s)
- Haiyan Wang
- Department of Ultrasonography Center, Tai'an City Central Hospital, Tai'an, China
| | - Lizhi Huang
- Department of Thoracic Surgery, Shenzhen Bao'an People's Hospital (Group), Shenzhen, China
| | - Li Chen
- Department of Vascular, Tai'an City Central Hospital, Tai'an, China
| | - Jing Ji
- Department of Geriatrics, Tai'an City Central Hospital, Tai'an, China
| | - Yuanyuan Zheng
- Department of Radiotherapy, Tai'an City Central Hospital, Tai'an, China
| | - Zhen Wang
- Department of Thoracic Oncology, Sun Yat-sen University Cancer Center, Guangzhou, China
| |
Collapse
|
48
|
Grant SN, Lester HA. Regulation of epithelial sodium channel activity by SARS-CoV-1 and SARS-CoV-2 proteins. Biophys J 2021; 120:2805-2813. [PMID: 34197807 PMCID: PMC8238646 DOI: 10.1016/j.bpj.2021.06.005] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 04/21/2021] [Accepted: 06/03/2021] [Indexed: 01/06/2023] Open
Abstract
Severe acute respiratory syndrome (SARS) coronavirus (CoV) 2 (SARS-CoV-2), which causes the coronavirus disease 2019, encodes several proteins whose roles are poorly understood. We tested their ability either to directly form plasma membrane ion channels or to change functions of two mammalian plasma membrane ion channels, the epithelial sodium channel (ENaC) and the α3β4 nicotinic acetylcholine receptor. In mRNA-injected Xenopus oocytes, none of nine SARS-CoV-2 proteins or two SARS-CoV-1 proteins produced conductances, nor did co-injection of several combinations. Immunoblots for ORF8, spike (S), and envelope (E) proteins revealed that the proteins are expressed at appropriate molecular weights. In experiments on coexpression with ENaC, three tested SARS proteins (SARS-CoV-1 E, SARS-CoV-2 E, and SARS-CoV-2 S) markedly decrease ENaC currents. SARS-CoV-1 S protein decreases ENaC currents modestly. Coexpressing the E proteins but not the S proteins with α3β4 nicotinic acetylcholine receptors significantly reduces acetylcholine-induced currents. ENaC inhibition does not occur if the SARS-CoV protein mRNAs are injected 24 h after the ENaC mRNAs, suggesting that SARS-CoV proteins affect early step(s) in functional expression of channel proteins. Consistent with the hypothesis that the SARS-CoV-2 S protein-induced ENaC inhibition involves competition for available protease, mutating the furin cleavage site in SARS-CoV-2 S protein partially relieves inhibition of ENaC currents. Extending previous suggestions that SARS proteins affect ENaC currents via protein kinase C (PKC) activation, PKC activation via phorbol 12-myristate 13-acetate decreases ENaC and α3β4 activity. Phorbol 12-myristate 13-acetate application reduced membrane capacitance ∼5%, presumably via increased endocytosis, but this decrease is much smaller than the SARS proteins' effects on conductances. Also, incubating oocytes in Gö-6976, a PKCα and PKCβ inhibitor, did not alter E or S protein-induced channel inhibition. We conclude that SARS-CoV-1 and SARS-CoV-2 proteins alter the function of human plasma membrane channels, via incompletely understood mechanisms. These interactions may play a role in the coronavirus 2019 pathophysiology.
Collapse
Affiliation(s)
- Stephen N Grant
- Division of Chemistry and Chemical Engineering, Pasadena, California
| | - Henry A Lester
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California.
| |
Collapse
|
49
|
Grant GJ, Mimche PN, Paine R, Liou TG, Qian WJ, Helms MN. Enhanced epithelial sodium channel activity in neonatal Scnn1b mouse lung attenuates high oxygen-induced lung injury. Am J Physiol Lung Cell Mol Physiol 2021; 321:L29-L41. [PMID: 33949206 PMCID: PMC8321857 DOI: 10.1152/ajplung.00538.2020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 04/26/2021] [Accepted: 04/27/2021] [Indexed: 11/22/2022] Open
Abstract
Prolonged oxygen therapy leads to oxidative stress, epithelial dysfunction, and acute lung injury in preterm infants and adults. Heterozygous Scnn1b mice, which overexpress lung epithelial sodium channels (ENaC), and their wild-type (WT) C57Bl6 littermates were utilized to study the pathogenesis of high fraction inspired oxygen ([Formula: see text])-induced lung injury. Exposure to high [Formula: see text] from birth to postnatal (PN) day 11 was used to model oxidative stress. Chronic exposure of newborn pups to 85% O2 increased glutathione disulfide (GSSG) and elevated the GSH/GSSG redox potential (Eh) of bronchoalveolar lavage fluid (BALF). Longitudinal X-ray imaging and Evans blue-labeled-albumin assays showed that chronic 85% O2 and acute GSSG (400 µM) exposures decreased alveolar fluid clearance (AFC) in the WT lung. Morphometric analysis of WT pups insufflated with GSSG (400 µM) or amiloride (1 µM) showed a reduction in alveologenesis and increased lung injury compared with age-matched control pups. The Scnn1b mouse lung phenotype was not further aggravated by chronic 85% O2 exposure. These outcomes support the hypothesis that exposure to hyperoxia increases GSSG, resulting in reduced lung fluid reabsorption due to inhibition of amiloride-sensitive ENaC. Flavin adenine dinucleotide (FADH2; 10 µM) was effective in recycling GSSG in vivo and promoted alveologenesis, but did not impact AFC nor attenuate fibrosis following high [Formula: see text] exposure. In conclusion, the data indicate that FADH2 may be pivotal for normal lung development, and show that ENaC is a key factor in promoting alveologenesis, sustaining AFC, and attenuating fibrotic lung injury caused by prolonged oxygen therapy in WT mice.
Collapse
Affiliation(s)
- Garett J Grant
- Division of Respiratory, Critical Care and Occupational Pulmonary Medicine, Department of Internal Medicine, University of Utah, Salt Lake City, Utah
| | - Patrice N Mimche
- Division of Microbiology and Immunology, Department of Pathology, University of Utah, Salt Lake City, Utah
| | - Robert Paine
- Division of Respiratory, Critical Care and Occupational Pulmonary Medicine, Department of Internal Medicine, University of Utah, Salt Lake City, Utah
| | - Theodore G Liou
- Division of Respiratory, Critical Care and Occupational Pulmonary Medicine, Department of Internal Medicine, University of Utah, Salt Lake City, Utah
| | - Wei-Jun Qian
- Biological Science Division, Pacific Northwest National Laboratory, Richland, Washington
| | - My N Helms
- Division of Respiratory, Critical Care and Occupational Pulmonary Medicine, Department of Internal Medicine, University of Utah, Salt Lake City, Utah
| |
Collapse
|
50
|
Abstract
Among the 5 taste qualities, salt is the least understood. The receptors, their expression pattern in taste cells, and the transduction mechanisms for salt taste are still unclear. Previous studies have suggested that low concentrations of NaCl are detected by the amiloride-sensitive epithelial Na+ channel (ENaC), which in other systems requires assembly of 3 homologous subunits (α, β, and γ) to form a functional channel. However, a new study from Lossow and colleagues, published in this issue of Chemical Senses, challenges that hypothesis by examining expression levels of the 3 ENaC subunits in individual taste cells using gene-targeted mice in combination with immunohistochemistry and in situ hybridization. Results show a lack of colocalization of ENaC subunits in taste cells as well as expression of subunits in taste cells that show no amiloride sensitivity. These new results question the molecular identity of the amiloride-sensitive Na+ conductance in taste cells.
Collapse
Affiliation(s)
- Aurelie Vandenbeuch
- Department of Otolaryngology and Rocky Mountain Taste and Smell Center, University of Colorado-Anschutz Medical Campus, Aurora, USA
| | - Sue C Kinnamon
- Department of Otolaryngology and Rocky Mountain Taste and Smell Center, University of Colorado-Anschutz Medical Campus, Aurora, USA
| |
Collapse
|