1
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Wiener SV. Effects of the environment on the evolution of the vertebrate urinary tract. Nat Rev Urol 2023; 20:719-738. [PMID: 37443264 DOI: 10.1038/s41585-023-00794-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/12/2023] [Indexed: 07/15/2023]
Abstract
Evolution of the vertebrate urinary system occurs in response to numerous selective pressures, which have been incompletely characterized. Developing research into urinary evolution led to the occurrence of clinical applications and insights in paediatric urology, reproductive medicine, urolithiasis and other domains. Each nephron segment and urinary organ has functions that can be contextualized within an evolutionary framework. For example, the structure and function of the glomerulus and proximal tubule are highly conserved, enabling blood cells and proteins to be retained, and facilitating the elimination of oceanic Ca+ and Mg+. Urea emerged as an osmotic mediator during evolution, as cells of large organisms required increased precision in the internal regulation of salinity and solutes. As the first vertebrates moved from water to land, acid-base regulation was shifted from gills to skin and kidneys in amphibians. In reptiles and birds, solute regulation no longer occurred through the skin but through nasal salt glands and post-renally, within the cloaca and the rectum. In placental mammals, nasal salt glands are absent and the rectum and urinary tracts became separate, which limited post-renal urine concentration and led to the necessity of a kidney capable of high urine concentration. Considering the evolutionary and environmental selective pressures that have contributed to renal evolution can help to gain an increased understanding of renal physiology.
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Affiliation(s)
- Scott V Wiener
- Department of Urology, SUNY Upstate Medical University, Syracuse, NY, USA.
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2
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Douglas LEJ, Reihill JA, Montgomery BM, Martin SL. Furin as a therapeutic target in cystic fibrosis airways disease. Eur Respir Rev 2023; 32:32/168/220256. [PMID: 37137509 PMCID: PMC10155048 DOI: 10.1183/16000617.0256-2022] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Accepted: 02/22/2023] [Indexed: 05/05/2023] Open
Abstract
Clinical management of cystic fibrosis (CF) has been greatly improved by the development of small molecule modulators of the CF transmembrane conductance regulator (CFTR). These drugs help to address some of the basic genetic defects of CFTR; however, no suitable CFTR modulators exist for 10% of people with CF (PWCF). An alternative, mutation-agnostic therapeutic approach is therefore still required. In CF airways, elevated levels of the proprotein convertase furin contribute to the dysregulation of key processes that drive disease pathogenesis. Furin plays a critical role in the proteolytic activation of the epithelial sodium channel; hyperactivity of which causes airways dehydration and loss of effective mucociliary clearance. Furin is also responsible for the processing of transforming growth factor-β, which is increased in bronchoalveolar lavage fluid from PWCF and is associated with neutrophilic inflammation and reduced pulmonary function. Pathogenic substrates of furin include Pseudomonas exotoxin A, a major toxic product associated with Pseudomonas aeruginosa infection and the spike glycoprotein of severe acute respiratory syndrome coronavirus 2, the causative pathogen for coronavirus disease 2019. In this review we discuss the importance of furin substrates in the progression of CF airways disease and highlight selective furin inhibition as a therapeutic strategy to provide clinical benefit to all PWCF.
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Affiliation(s)
- Lisa E J Douglas
- School of Pharmacy, Queen's University Belfast, Belfast, Northern Ireland, UK
| | - James A Reihill
- School of Pharmacy, Queen's University Belfast, Belfast, Northern Ireland, UK
| | | | - S Lorraine Martin
- School of Pharmacy, Queen's University Belfast, Belfast, Northern Ireland, UK
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3
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Lemmens-Gruber R, Tzotzos S. The Epithelial Sodium Channel-An Underestimated Drug Target. Int J Mol Sci 2023; 24:ijms24097775. [PMID: 37175488 PMCID: PMC10178586 DOI: 10.3390/ijms24097775] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 04/14/2023] [Accepted: 04/15/2023] [Indexed: 05/15/2023] Open
Abstract
Epithelial sodium channels (ENaC) are part of a complex network of interacting biochemical pathways and as such are involved in several disease states. Dependent on site and type of mutation, gain- or loss-of-function generated symptoms occur which span from asymptomatic to life-threatening disorders such as Liddle syndrome, cystic fibrosis or generalized pseudohypoaldosteronism type 1. Variants of ENaC which are implicated in disease assist further understanding of their molecular mechanisms in order to create models for specific pharmacological targeting. Identification and characterization of ENaC modifiers not only furthers our basic understanding of how these regulatory processes interact, but also enables discovery of new therapeutic targets for the disease conditions caused by ENaC dysfunction. Numerous test compounds have revealed encouraging results in vitro and in animal models but less in clinical settings. The EMA- and FDA-designated orphan drug solnatide is currently being tested in phase 2 clinical trials in the setting of acute respiratory distress syndrome, and the NOX1/ NOX4 inhibitor setanaxib is undergoing clinical phase 2 and 3 trials for therapy of primary biliary cholangitis, liver stiffness, and carcinoma. The established ENaC blocker amiloride is mainly used as an add-on drug in the therapy of resistant hypertension and is being studied in ongoing clinical phase 3 and 4 trials for special applications. This review focuses on discussing some recent developments in the search for novel therapeutic agents.
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Affiliation(s)
- Rosa Lemmens-Gruber
- Department of Pharmaceutical Sciences, Division of Pharmacology and Toxicology, University of Vienna, A-1090 Vienna, Austria
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4
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Coelho Almeida A, Bastos Gomes M, Martins SA, Marques OP, Gomes MM, Antunes AM. A case of severe systemic type 1 pseudohypoaldosteronism with 10 years of evolution. J Pediatr Endocrinol Metab 2022; 35:1448-1452. [PMID: 35918792 DOI: 10.1515/jpem-2022-0201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Accepted: 06/27/2022] [Indexed: 11/15/2022]
Abstract
Type 1 pseudohypoaldosteronism (PHA-1) is a rare genetic syndrome of unresponsiveness to aldosterone and presents in the neonatal period with hyperkalemia, hyponatremia and metabolic acidosis. The mortality rate can be high and multidisciplinary team is needed for optimal management and adequate growth and development of these patients. Many genotype-phenotype correlations remain uncertain, and the description of the evolution of cases can increase scientific knowledge about the psychomotor development and severity of the different mutations. We report the follow-up for the last 10 years of a patient, with previously unrecognized genetic findings identified. In addition, we reviewed the literature and compared it with other pediatric cases.
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Affiliation(s)
- André Coelho Almeida
- Department of Pediatrics and Neonatology, Centro Hospitalar de Trás-Os-Montes e Alto Douro, Vila Real, Portugal
| | - Mariana Bastos Gomes
- Department of Pediatrics, Unidade Local de Saúde do Alto Minho, Viana do Castelo, Portugal
| | - Sofia A Martins
- Pediatric Endocrinology and Diabetology Unit, Hospital de Braga, Braga, Portugal
| | | | - Maria Miguel Gomes
- Pediatric Endocrinology and Diabetology Unit, Hospital de Braga, Braga, Portugal.,School of Medicine, University of Minho, Braga, Portugal
| | - Ana M Antunes
- Pediatric Endocrinology and Diabetology Unit, Hospital de Braga, Braga, Portugal
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5
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Brown EF, Mitaera T, Fronius M. COVID-19 and Liquid Homeostasis in the Lung—A Perspective through the Epithelial Sodium Channel (ENaC) Lens. Cells 2022; 11:cells11111801. [PMID: 35681496 PMCID: PMC9180030 DOI: 10.3390/cells11111801] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Revised: 05/23/2022] [Accepted: 05/25/2022] [Indexed: 01/26/2023] Open
Abstract
Infections with a new corona virus in 2019 lead to the definition of a new disease known as Corona Virus Disease 2019 (COVID-19). The sever cases of COVID-19 and the main cause of death due to virus infection are attributed to respiratory distress. This is associated with the formation of pulmonary oedema that impairs blood oxygenation and hypoxemia as main symptoms of respiratory distress. An important player for the maintenance of a defined liquid environment in lungs needed for normal lung function is the epithelial sodium channel (ENaC). The present article reviews the implications of SARS-CoV-2 infections from the perspective of impaired function of ENaC. The rationale for this perspective is derived from the recognition that viral spike protein and ENaC share a common proteolytic cleavage site. This cleavage site is utilized by the protease furin, that is essential for ENaC activity. Furin cleavage of spike ‘activates’ the virus protein to enable binding to host cell membrane receptors and initiate cell infection. Based on the importance of proteolytic cleavage for ENaC function and activation of spike, it seems feasible to assume that virus infections are associated with impaired ENaC activity. This is further supported by symptoms of COVID-19 that are reminiscent of impaired ENaC function in the respiratory tract.
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Affiliation(s)
- Emily F. Brown
- Department of Physiology, University of Otago, Dunedin 9054, New Zealand; (E.F.B.); (T.M.)
- HeartOtago, University of Otago, Dunedin, New Zealand
| | - Tamapuretu Mitaera
- Department of Physiology, University of Otago, Dunedin 9054, New Zealand; (E.F.B.); (T.M.)
- HeartOtago, University of Otago, Dunedin, New Zealand
| | - Martin Fronius
- Department of Physiology, University of Otago, Dunedin 9054, New Zealand; (E.F.B.); (T.M.)
- HeartOtago, University of Otago, Dunedin, New Zealand
- Healthy Hearts for Aotearoa New Zealand, Centre of Research Excellence, New Zealand
- Maurice Wilkins Centre for Molecular Discovery, Centre of Research Excellence, New Zealand
- Correspondence: ; Tel.: +64-3-471-6081
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6
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Pugh CP. Pseudohypoaldosteronism Type 1: The Presentation and Management of a Neonate With a Novel Mutation of the SCNN1B Gene Found in Two Hispanic Siblings. Cureus 2022; 14:e23918. [PMID: 35530903 PMCID: PMC9076053 DOI: 10.7759/cureus.23918] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/07/2022] [Indexed: 11/18/2022] Open
Abstract
Pseudohypoaldosteronism type 1 (PHA1) may manifest in the neonatal period as a life-threatening salt-wasting syndrome providing challenges in recognition and treatment. This case describes a newborn who developed severe dehydration and electrolyte imbalances and subsequently was found to have a novel SCNN1B gene variant resulting in autosomal recessive systemic PHA1.
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Douglas LEJ, Reihill JA, Ho MWY, Axten JM, Campobasso N, Schneck JL, Rendina AR, Wilcoxen KM, Martin SL. A highly selective, cell-permeable furin inhibitor BOS-318 rescues key features of cystic fibrosis airway disease. Cell Chem Biol 2022; 29:947-957.e8. [PMID: 35202587 DOI: 10.1016/j.chembiol.2022.02.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 12/14/2021] [Accepted: 02/01/2022] [Indexed: 12/15/2022]
Abstract
In cystic fibrosis (CF), excessive furin activity plays a critical role in the activation of the epithelial sodium channel (ENaC), dysregulation of which contributes to airway dehydration, ineffective mucociliary clearance (MCC), and mucus obstruction. Here, we report a highly selective, cell-permeable furin inhibitor, BOS-318, that derives selectivity by eliciting the formation of a new, unexpected binding pocket independent of the active site catalytic triad. Using human ex vivo models, BOS-318 showed significant suppression of ENaC, which led to enhanced airway hydration and an ∼30-fold increase in MCC rate. Furin inhibition also protected ENaC from subsequent activation by neutrophil elastase, a soluble protease dominant in CF airways. Additional therapeutic benefits include protection against epithelial cell death induced by Pseudomonas aeruginosa exotoxin A. Our findings demonstrate the utility of selective furin inhibition as a mutation-agnostic approach that can correct features of CF airway pathophysiology in a manner expected to deliver therapeutic value.
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Affiliation(s)
- Lisa E J Douglas
- School of Pharmacy, Queen's University Belfast, Belfast BT9 7BL, Northern Ireland, UK
| | - James A Reihill
- School of Pharmacy, Queen's University Belfast, Belfast BT9 7BL, Northern Ireland, UK
| | - Melisa W Y Ho
- GlaxoSmithKline Research and Development, Collegeville, PA 19426, USA
| | - Jeffrey M Axten
- GlaxoSmithKline Research and Development, Collegeville, PA 19426, USA
| | - Nino Campobasso
- GlaxoSmithKline Research and Development, Collegeville, PA 19426, USA
| | - Jessica L Schneck
- GlaxoSmithKline Research and Development, Collegeville, PA 19426, USA
| | - Alan R Rendina
- GlaxoSmithKline Research and Development, Collegeville, PA 19426, USA
| | | | - S Lorraine Martin
- School of Pharmacy, Queen's University Belfast, Belfast BT9 7BL, Northern Ireland, UK.
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8
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Cellular and molecular architecture of submucosal glands in wild-type and cystic fibrosis pigs. Proc Natl Acad Sci U S A 2022; 119:2119759119. [PMID: 35046051 PMCID: PMC8794846 DOI: 10.1073/pnas.2119759119] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/03/2021] [Indexed: 12/13/2022] Open
Abstract
Submucosal glands (SMGs) protect lungs but can also contribute to disease. For example, in cystic fibrosis (CF), SMGs produce abnormal mucus that disrupts mucociliary transport. CF is an ion transport disease, yet knowledge of the ion transporters expressed by SMG acini, which produce mucus, and SMG ducts that carry it to the airway lumen is limited. Therefore, we isolated SMGs from newborn pigs and used single-cell messenger RNA sequencing, immunohistochemistry, and in situ hybridization to identify cell types, gene expression, and spatial distribution. Cell types and transcript levels were the same in non-CF and CF SMGs, suggesting that loss of epithelial anion secretion rather than an intrinsic cell defect causes CF mucus abnormalities. Gene signatures of acinar mucous and acinar serous cells revealed specialized functions in producing mucins and antimicrobials, respectively. However, surprisingly, these two cell types expressed the same ion transporters and neurohumoral receptors, suggesting the importance of balancing mucin and liquid secretion to produce optimal mucus properties. SMG duct cell transcripts suggest that they secrete HCO3- and Cl-, and thus have some similarity to pancreatic ducts that are also defective in CF. These and additional findings suggest the functions of the SMG acinus and duct and provide a baseline for understanding how environmental and genetic challenges impact their contribution to lung disease.
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9
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Corcoran TE, Huber AS, Hill SL, Locke LW, Weber L, Muthukrishnan A, Heidrich EM, Wenzel S, Myerburg MM. Mucociliary Clearance Differs in Mild Asthma by Levels of Type 2 Inflammation. Chest 2021; 160:1604-1613. [PMID: 34029561 PMCID: PMC8628176 DOI: 10.1016/j.chest.2021.05.013] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2020] [Revised: 04/30/2021] [Accepted: 05/03/2021] [Indexed: 11/27/2022] Open
Abstract
BACKGROUND Although mucus plugging is a well-reported feature of asthma, whether asthma and type 2 inflammation affect mucociliary clearance (MCC) is unknown. RESEARCH QUESTION Does type 2 inflammation influence mucus clearance rates in patients with mild asthma who are not receiving corticosteroids? STUDY DESIGN AND METHODS The clearance rates of inhaled radiolabeled particles were compared between patients with mild asthma with low (n = 17) and high (n = 18) levels of T2 inflammation. Fraction exhaled nitric oxide (Feno) was used to prospectively segregate subjects into T2 Lo (Feno < 25 ppb) and T2 Hi (Feno > 35 ppb) cohorts. Bronchial brush samples were collected with fiber-optic bronchoscopy, and quantitative polymerase chain reaction was performed to measure expression of genes associated with T2 asthma. MCC rate comparisons were also made with a historical group of healthy control subjects (HCs, n = 12). RESULTS The T2 Lo cohort demonstrated increased MCC when compared with both T2 Hi and historic HCs. MCC within the T2 Hi group varied significantly, with some subjects having low or zero clearance. MCC decreased with increasing expression of several markers of T2 airway inflammation (CCL26, NOS2, and POSTN) and with Feno. MUC5AC and FOXJ1 expression was similar between the T2Lo and T2Hi cohorts. INTERPRETATION Increasing T2 inflammation was associated with decreasing MCC. High rates of MCC in T2 Lo subjects may indicate a compensatory mechanism present in mild disease but lost with high levels of inflammation. Future studies are required to better understand mechanisms and whether impairments in MCC in more severe asthma drive worse clinical outcomes.
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Affiliation(s)
- Timothy E Corcoran
- Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine, University of Pittsburgh, PA; Department of Bioengineering, University of Pittsburgh, PA; Department of Chemical and Petroleum Engineering, University of Pittsburgh, PA.
| | - Alex S Huber
- Department of Chemical and Petroleum Engineering, University of Pittsburgh, PA
| | - Sherri L Hill
- Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine, University of Pittsburgh, PA
| | - Landon W Locke
- Department of Microbial Infection and Immunity, The Ohio State University, Columbus, OH
| | - Lawrence Weber
- Nuclear Medicine Department, University of Pittsburgh Medical Center, PA
| | | | - Elisa M Heidrich
- Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine, University of Pittsburgh, PA
| | - Sally Wenzel
- Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine, University of Pittsburgh, PA; Department of Environmental & Occupational Health, University of Pittsburgh, PA
| | - Mike M Myerburg
- Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine, University of Pittsburgh, PA
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10
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Combined agonists act synergistically to increase mucociliary clearance in a cystic fibrosis airway model. Sci Rep 2021; 11:18828. [PMID: 34552115 PMCID: PMC8458446 DOI: 10.1038/s41598-021-98122-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Accepted: 09/03/2021] [Indexed: 11/30/2022] Open
Abstract
Mucus clearance, a primary innate defense mechanism of airways, is defective in patients with cystic fibrosis (CF) and CF animals. In previous work, the combination of a low dose of the cholinergic agonist, carbachol with forskolin or a β adrenergic agonist, isoproterenol synergistically increased mucociliary clearance velocity (MCCV) in ferret tracheas. Importantly, the present study shows that synergistic MCCV can also be produced in CF ferrets, with increases ~ 55% of WT. Synergistic MCCV was also produced in pigs. The combined agonists increased MCCV by increasing surface fluid via multiple mechanisms: increased fluid secretion from submucosal glands, increased anion secretion across surface epithelia and decreased Na+ absorption. To avoid bronchoconstriction, the cAMP agonist was applied 30 min before carbachol. This approach to increasing mucus clearance warrants testing for safety and efficacy in humans as a potential therapeutic for muco-obstructive diseases.
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11
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Ryznychuk MO, Pishak VP, Bacyuk-Ponych NV, Pishak OV. Hereditary tubulopathies accompanying polyuia. REGULATORY MECHANISMS IN BIOSYSTEMS 2021. [DOI: 10.15421/022161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Tubulopathies are a group of heterogeneous diseases that are manifested in the malfunction of the renal tubules. This review addresses tubulopathies associated with polyuria syndrome, namely renal glucosuria syndrome, nephrogenic diabetes insipidus and pseudohyperaldosteronism. Types of renal glucosuria are described, namely: type A, type B and the most severe type 0. Type A is characterized by a low filtration threshold and low glucose reabsorption. The type of inheritance is autosomal recessive. Type B, autosomal dominant, is characterized by uneven activity of glucose transport, in which its reabsorption is reduced only in some nephrons. That is, normal reabsorption of glucose is maintained, but the filtration threshold of the latter is reduced. Type 0 with a severe course is characterized by complete inability of epithelial cells of the proximal tubules to reabsorb glucose. Nephrogenic diabetes insipidus is a rare inherited disease caused by impaired response of the renal tubules to antidiuretic hormone (ADH). Depending on the degree of inability to concentrate urine, there are complete and partial forms. It is divided into nephrogenic diabetes insipidus type I (X-linked recessive); nephrogenic diabetes insipidus type II (autosomal recessive and autosomal dominant) and nephrogenic diabetes insipidus syndrome with dementia and intracerebral calcifications (type of inheritance remains unknown). Children with autosomal recessive type of inheritance suffer from the more severe disease course. Pseudohypoaldosteronism is characterized by a special condition of the renal tubules which is due to insufficient sensitivity of the tubular epithelium to aldosterone, which in turn leads to hyperaldosteronism, the development of hyponatremia, metabolic acidosis with hyperkalemia, polydipsia and polyuria, decreased sodium reabsorption and retardation of the child's physical development. The classification includes three syndromes of pseudohypoaldosteronism, namely: type I (PHA1), which is divided into PHA1A (autosomal dominant, renal), PHA1B (autosomal recessive, systemic); type II (PHA2; Gordon’s syndrome), type III (secondary), which develops as a result of renal pathology.
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12
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Abstract
The Epithelial Na+ Channel, ENaC, comprised of 3 subunits (αβγ, or sometimes δβγENaC), plays a critical role in regulating salt and fluid homeostasis in the body. It regulates fluid reabsorption into the blood stream from the kidney to control blood volume and pressure, fluid absorption in the lung to control alveolar fluid clearance at birth and maintenance of normal airway surface liquid throughout life, and fluid absorption in the distal colon and other epithelial tissues. Moreover, recent studies have also revealed a role for sodium movement via ENaC in nonepithelial cells/tissues, such as endothelial cells in blood vessels and neurons. Over the past 25 years, major advances have been made in our understanding of ENaC structure, function, regulation, and role in human disease. These include the recently solved three-dimensional structure of ENaC, ENaC function in various tissues, and mutations in ENaC that cause a hereditary form of hypertension (Liddle syndrome), salt-wasting hypotension (PHA1), or polymorphism in ENaC that contributes to other diseases (such as cystic fibrosis). Moreover, great strides have been made in deciphering the regulation of ENaC by hormones (e.g., the mineralocorticoid aldosterone, glucocorticoids, vasopressin), ions (e.g., Na+ ), proteins (e.g., the ubiquitin-protein ligase NEDD4-2, the kinases SGK1, AKT, AMPK, WNKs & mTORC2, and proteases), and posttranslational modifications [e.g., (de)ubiquitylation, glycosylation, phosphorylation, acetylation, palmitoylation]. Characterization of ENaC structure, function, regulation, and role in human disease, including using animal models, are described in this article, with a special emphasis on recent advances in the field. © 2021 American Physiological Society. Compr Physiol 11:1-29, 2021.
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Affiliation(s)
- Daniela Rotin
- The Hospital for Sick Children, and The University of Toronto, Toronto, Canada
| | - Olivier Staub
- Department of Biomedical Sciences, University of Lausanne, Lausanne, Switzerland
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13
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Abdalla A, Alhassan MA, Tawfeeg R, Sanad A, Tawamie H, Abdullah M. Systemic pseudohypoaldosteronism-1 with episodic dyslipidemia in a Sudanese child. Endocrinol Diabetes Metab Case Rep 2021; 2021:EDM210010. [PMID: 34165441 PMCID: PMC8240716 DOI: 10.1530/edm-21-0010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Accepted: 05/25/2021] [Indexed: 11/08/2022] Open
Abstract
SUMMARY Systemic pseudohypoaldosteronism type 1 (PHA1) is a rare genetic syndrome of tissue unresponsiveness to aldosterone caused by mutations affecting the epithelial Na channel (ENaC). The classical presentation is life-threatening neonatal/infantile salt-losing crises that mimic congenital adrenal hyperplasia (CAH). Consistently, extra-renal manifestations, including respiratory symptoms that resemble cystic fibrosis, are well reported. Clinical diagnosis is made by the presence of hyponatremia, hyperkalemia, metabolic acidosis, respiratory symptoms, evidence of high renal and extra-renal salt loss in addition to high plasma renin and aldosterone levels. We herein report a novel manifestation of PHA1: episodic dyslipidemia in a 7-month-old Sudanese boy that occurred during the salt-losing crises. Whole exome sequencing of the patient revealed one homozygous missense variant c.1636G>A p.(Asp546Asn) in the SCNN1B gene, confirming our clinical and laboratory findings that were compatible with PHA1. This report aims to highlight the possible explanation of dyslipidemia in PHA1 and its expected consequences in the long term. LEARNING POINTS A child presenting with features that mimic salt-losing congenital adrenal hyperplasia (CAH) crises that do not respond to glucocorticoid and mineralocorticoid therapy should alert the pediatricians to the possibility of end-organ resistance to aldosterone. Pseudohypoaldosteronism type 1 (PHA1) can be diagnosed even in the absence of advanced laboratory investigations. To our knowledge, this is the first case of systemic PHA1 to have a documented episodic dyslipidemia (primarily as marked hypertriglyceridemia).
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Affiliation(s)
- Asmahan Abdalla
- Department of Pediatric Endocrinologist, Gaafar Ibn Auf Children’s Tertiary Hospital, Khartoum, Sudan
| | | | - Reem Tawfeeg
- Department of Pediatric Respirologist, Elswaidi Charity Hospital, Khartoum, Sudan
| | - Ayman Sanad
- Department of Pediatrics, University of Shendi, Shendi, Sudan
| | - Hasan Tawamie
- Clinical Lab Operations at Centogene Laboratory, Rostock, Mecklenburg-Vorpommern, Germany
| | - Mohamed Abdullah
- Departmentof Pediatric Endocrinology, Faculty of Medicine, University of Khartoum, Khartoum, Sudan
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14
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McKelvey MC, Brown R, Ryan S, Mall MA, Weldon S, Taggart CC. Proteases, Mucus, and Mucosal Immunity in Chronic Lung Disease. Int J Mol Sci 2021; 22:5018. [PMID: 34065111 PMCID: PMC8125985 DOI: 10.3390/ijms22095018] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Revised: 05/06/2021] [Accepted: 05/06/2021] [Indexed: 12/13/2022] Open
Abstract
Dysregulated protease activity has long been implicated in the pathogenesis of chronic lung diseases and especially in conditions that display mucus obstruction, such as chronic obstructive pulmonary disease, cystic fibrosis, and non-cystic fibrosis bronchiectasis. However, our appreciation of the roles of proteases in various aspects of such diseases continues to grow. Patients with muco-obstructive lung disease experience progressive spirals of inflammation, mucostasis, airway infection and lung function decline. Some therapies exist for the treatment of these symptoms, but they are unable to halt disease progression and patients may benefit from novel adjunct therapies. In this review, we highlight how proteases act as multifunctional enzymes that are vital for normal airway homeostasis but, when their activity becomes immoderate, also directly contribute to airway dysfunction, and impair the processes that could resolve disease. We focus on how proteases regulate the state of mucus at the airway surface, impair mucociliary clearance and ultimately, promote mucostasis. We discuss how, in parallel, proteases are able to promote an inflammatory environment in the airways by mediating proinflammatory signalling, compromising host defence mechanisms and perpetuating their own proteolytic activity causing structural lung damage. Finally, we discuss some possible reasons for the clinical inefficacy of protease inhibitors to date and propose that, especially in a combination therapy approach, proteases represent attractive therapeutic targets for muco-obstructive lung diseases.
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Affiliation(s)
- Michael C. McKelvey
- Airway Innate Immunity Research (AiiR) Group, Wellcome-Wolfson Institute for Experimental Medicine, Queen’s University Belfast, Belfast BT9 7BL, UK; (M.C.M.); (R.B.); (S.R.); (S.W.)
| | - Ryan Brown
- Airway Innate Immunity Research (AiiR) Group, Wellcome-Wolfson Institute for Experimental Medicine, Queen’s University Belfast, Belfast BT9 7BL, UK; (M.C.M.); (R.B.); (S.R.); (S.W.)
| | - Sinéad Ryan
- Airway Innate Immunity Research (AiiR) Group, Wellcome-Wolfson Institute for Experimental Medicine, Queen’s University Belfast, Belfast BT9 7BL, UK; (M.C.M.); (R.B.); (S.R.); (S.W.)
| | - Marcus A. Mall
- Department of Pediatric Respiratory Medicine, Immunology and Critical Care Medicine, Charité—Universitätsmedizin Berlin, 13353 Berlin, Germany;
- Berlin Institute of Health (BIH), 10178 Berlin, Germany
- German Center for Lung Research (DZL), 35392 Gießen, Germany
| | - Sinéad Weldon
- Airway Innate Immunity Research (AiiR) Group, Wellcome-Wolfson Institute for Experimental Medicine, Queen’s University Belfast, Belfast BT9 7BL, UK; (M.C.M.); (R.B.); (S.R.); (S.W.)
| | - Clifford C. Taggart
- Airway Innate Immunity Research (AiiR) Group, Wellcome-Wolfson Institute for Experimental Medicine, Queen’s University Belfast, Belfast BT9 7BL, UK; (M.C.M.); (R.B.); (S.R.); (S.W.)
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15
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Shabbir W, Topcagic N, Aufy M. Activation of autosomal recessive Pseudohypoaldosteronism1 ENaC with aldosterone. Eur J Pharmacol 2021; 901:174090. [PMID: 33831414 DOI: 10.1016/j.ejphar.2021.174090] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Revised: 03/26/2021] [Accepted: 03/31/2021] [Indexed: 11/28/2022]
Abstract
The mineralocorticoid hormone aldosterone stimulates sodium reabsorption in the collecting ducts by increasing the activity of the epithelial sodium channel (ENaC). Being a rate-liming channel the loss of function mutations caused Pseudohypoaldosteronism 1 (PHA1). Despite elevated plasma aldosterone in PHA 1 patients the modulation of PHA 1 causing ENaC mutants with hormone has never been studied. After recording control ENaC current in PHA1 causing ENaC stop codon mutants we demonstrated the activation of aldosterone in the whole cell as well as single channel patch clamp assays. Single channel recoding experiments demonstrated that aldosterone can increase the open probability of all analyzed PHA 1 stop codon mutants and WT. Additionally, we demonstrated by western blot experiments that aldosterone can increase the expression of WT and PHA 1 stop codon mutants. Extensive whole cell patch clamp experiments demonstrated that C-terminal γ ENaC domain is necessary for aldosterone to activate whole cell current in HEK-293 cells. This novel finding of γ ENaC C-terminus dependent activation of whole cell current by aldosterone could alter our understanding of ENaC-mediated sodium reabsorption in the aldosterone-sensitive distal nephron (ASDN).
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Affiliation(s)
- Waheed Shabbir
- Institute for Pharmacology and Toxicology, University of Vienna, Althanstrasse 14, A-1090, Vienna, Austria.
| | - Nermina Topcagic
- Institute for Pharmacology and Toxicology, University of Vienna, Althanstrasse 14, A-1090, Vienna, Austria
| | - Mohammed Aufy
- Institute for Pharmacology and Toxicology, University of Vienna, Althanstrasse 14, A-1090, Vienna, Austria
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16
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Mall MA. ENaC inhibition in cystic fibrosis: potential role in the new era of CFTR modulator therapies. Eur Respir J 2020; 56:13993003.00946-2020. [PMID: 32732328 PMCID: PMC7758539 DOI: 10.1183/13993003.00946-2020] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Accepted: 07/18/2020] [Indexed: 01/07/2023]
Abstract
Small-molecule cystic fibrosis transmembrane conductance regulator (CFTR) modulator drugs for cystic fibrosis are the first therapies since the disease was initially described by Fanconiet al. [1] in 1936 to target and partially restore the function of the CFTR Cl− channel. CFTR modulator therapy is expected to have significant clinical benefits for many, but it does not result in a cure and is not appropriate or available for all patients with cystic fibrosis [2, 3]. In this review, evidence is described suggesting that inhibiting the epithelial Na+ channel (ENaC) responsible for the Na+/fluid absorption that contributes to airway surface dehydration and impaired mucociliary clearance (MCC) observed in cystic fibrosis airways may significantly improve clinical outcomes irrespective of the CFTR genotype, and may synergise with currently approved CFTR modulators to further improve clinical outcomes. ENaC inhibition with BI 1265162 is a promising strategy to optimise outcomes in patients with CF either eligible, or ineligible, for CFTR modulator therapy. Phase II clinical trials of BI 1265162 must now show this translates into clinical benefit.https://bit.ly/2OQ1IUI
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Affiliation(s)
- Marcus A Mall
- Dept of Pediatric Pulmonology, Immunology and Critical Care Medicine, Charité - Universitätsmedizin Berlin, Berlin, Germany .,Berlin Institute of Health (BIH), Berlin, Germany.,German Center for Lung Research (DZL), associated partner site, Berlin, Germany
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17
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Rotem-Grunbaum B, Landau D. Genetic renal disease classification by hormonal axes. Pediatr Nephrol 2020; 35:2211-2219. [PMID: 31828468 DOI: 10.1007/s00467-019-04437-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2019] [Revised: 11/23/2019] [Accepted: 11/26/2019] [Indexed: 12/31/2022]
Abstract
The kidneys, which regulate many homeostatic pathways, are also a major endocrinological target organ. Many genetic renal diseases can be classified according to the affected protein along such endocrinological pathways. In this review, we examine the hypothesis that a more severe phenotype is expected as the affected protein is located more distally along such pathways. Thus, the location of a defect along its endocrinological pathway should be taken into consideration, in addition to the mutation type, when assessing genetic renal disease severity.
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Affiliation(s)
- Bar Rotem-Grunbaum
- Department of Pediatrics B, Schneider Children's Medical Center of Israel, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Daniel Landau
- Department of Pediatrics B, Schneider Children's Medical Center of Israel, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel.
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18
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Mukherjee A, MacDonald KD, Kim J, Henderson MI, Eygeris Y, Sahay G. Engineered mutant α-ENaC subunit mRNA delivered by lipid nanoparticles reduces amiloride currents in cystic fibrosis-based cell and mice models. SCIENCE ADVANCES 2020; 6:6/47/eabc5911. [PMID: 33208364 PMCID: PMC7673816 DOI: 10.1126/sciadv.abc5911] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Accepted: 10/05/2020] [Indexed: 05/02/2023]
Abstract
Cystic fibrosis (CF) results from mutations in the chloride-conducting CF transmembrane conductance regulator (CFTR) gene. Airway dehydration and impaired mucociliary clearance in CF is proposed to result in tonic epithelial sodium channel (ENaC) activity, which drives amiloride-sensitive electrogenic sodium absorption. Decreasing sodium absorption by inhibiting ENaC can reverse airway surface liquid dehydration. Here, we inhibit endogenous heterotrimeric ENaC channels by introducing inactivating mutant ENaC α mRNA (αmutENaC). Lipid nanoparticles carrying αmutENaC were transfected in CF-based airway cells in vitro and in vivo. We observed a significant decrease in macroscopic as well as amiloride-sensitive ENaC currents and an increase in airway surface liquid height in CF airway cells. Similarly, intranasal transfection of αmutENaC mRNA decreased amiloride-sensitive nasal potential difference in CFTRKO mice. These data suggest that mRNA-based ENaC inhibition is a powerful strategy for reducing mucus dehydration and has therapeutic potential for treating CF in all patients, independent of genotype.
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Affiliation(s)
- Anindit Mukherjee
- Department of Pharmaceutical Sciences, College of Pharmacy, Robertson Life Sciences Building, Oregon State University, Portland, OR 97201, USA
| | - Kelvin D MacDonald
- Department of Pharmaceutical Sciences, College of Pharmacy, Robertson Life Sciences Building, Oregon State University, Portland, OR 97201, USA
- Department of Pediatrics, School of Medicine, Oregon Health & Science University, Portland, OR 97239, USA
| | - Jeonghwan Kim
- Department of Pharmaceutical Sciences, College of Pharmacy, Robertson Life Sciences Building, Oregon State University, Portland, OR 97201, USA
| | - Michael I Henderson
- Department of Cell, Developmental and Cancer Biology, Oregon Health & Science University, Portland, OR 97201, USA
| | - Yulia Eygeris
- Department of Pharmaceutical Sciences, College of Pharmacy, Robertson Life Sciences Building, Oregon State University, Portland, OR 97201, USA
| | - Gaurav Sahay
- Department of Pharmaceutical Sciences, College of Pharmacy, Robertson Life Sciences Building, Oregon State University, Portland, OR 97201, USA.
- Department of Biomedical Engineering, Robertson Life Sciences Building, Oregon Health & Science University, Portland, OR 97239, USA
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19
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Hanukoglu A, Vargas-Poussou R, Landau Z, Yosovich K, Hureaux M, Zennaro MC. Renin-aldosterone system evaluation over four decades in an extended family with autosomal dominant pseudohypoaldosteronism due to a deletion in the NR3C2 gene. J Steroid Biochem Mol Biol 2020; 204:105755. [PMID: 33017655 DOI: 10.1016/j.jsbmb.2020.105755] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 09/14/2020] [Accepted: 09/15/2020] [Indexed: 10/23/2022]
Abstract
Renal pseudohypoaldosteronism (PHA1) is a mild form of an aldosterone-resistance syndrome caused by mutations in the NR3C2 gene that codes for the mineralocorticoid receptor (MR). The disease is inherited as an autosomal dominant trait characterized by signs and symptoms of salt-losing in infancy. Disease manifestations could be severe in infancy but improve after the age of 1-3 years. Some affected members are asymptomatic and remain so life-long. In this study, we report the identification of a large deletion in the NR3C2 gene (c.1897+1_1898-1)_(c.*2955+?)del in renal PHA1 patients from an extended family spanning four generations. We prospectively evaluated the plasma renin activity and serum aldosterone profiles over four decades in symptomatic and asymptomatic affected family members. The benefits of early diagnosis on the clinical outcome were assessed as well. The long-term follow-up showed an age-dependent decrease in both plasma renin activity and serum aldosterone levels over the years. However, aldosterone levels remain high life-long. Thus, levels of aldosterone are a reliable marker to detect asymptomatic family members. The diagnosis of the proposita led to early diagnosis and therapy in other affected family members, significantly mitigating the clinical course. Despite the extremely elevated serum aldosterone levels during pregnancy, affected pregnant women did not experience any ill effects. However, this should be verified by observations in other adult patients.
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Affiliation(s)
- Aaron Hanukoglu
- Division of Pediatric Endocrinology, E. Wolfson Medical Center, Holon, Israel; Sackler School of Medicine, Tel-Aviv University, Tel Aviv, Israel.
| | - Rosa Vargas-Poussou
- Assistance Publique-Hôpitaux de Paris, Hôpital Européen Georges Pompidou, Service de Génétique, Paris, France; Centre de Références de Maladies Rénales Rares de l'Enfant et d'Adulte (MARHEA)
| | - Zohar Landau
- Division of Pediatric Endocrinology, E. Wolfson Medical Center, Holon, Israel; Sackler School of Medicine, Tel-Aviv University, Tel Aviv, Israel
| | - Keren Yosovich
- Molecular Genetics Lab, Wolfson Medical Center, Holon, Israel
| | - Marguerite Hureaux
- Assistance Publique-Hôpitaux de Paris, Hôpital Européen Georges Pompidou, Service de Génétique, Paris, France; Inserm, PARCC, Université de Paris, F-75015 Paris, France
| | - Maria-Christina Zennaro
- Assistance Publique-Hôpitaux de Paris, Hôpital Européen Georges Pompidou, Service de Génétique, Paris, France; Inserm, PARCC, Université de Paris, F-75015 Paris, France
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20
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Baloglu E, Nonnenmacher G, Seleninova A, Berg L, Velineni K, Ermis-Kaya E, Mairbäurl H. The role of hypoxia-induced modulation of alveolar epithelial Na +- transport in hypoxemia at high altitude. Pulm Circ 2020; 10:50-58. [PMID: 33110497 PMCID: PMC7557693 DOI: 10.1177/2045894020936662] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Accepted: 06/02/2020] [Indexed: 12/14/2022] Open
Abstract
Reabsorption of excess alveolar fluid is driven by vectorial Na+-transport across alveolar epithelium, which protects from alveolar flooding and facilitates gas exchange. Hypoxia inhibits Na+-reabsorption in cultured cells and in-vivo by decreasing activity of epithelial Na+-channels (ENaC), which impairs alveolar fluid clearance. Inhibition also occurs during in-vivo hypoxia in humans and laboratory animals. Signaling mechanisms that inhibit alveolar reabsorption are poorly understood. Because cellular adaptation to hypoxia is regulated by hypoxia-inducible transcription factors (HIF), we tested whether HIFs are involved in decreasing Na+-transport in hypoxic alveolar epithelium. Expression of HIFs was suppressed in cultured rat primary alveolar epithelial cells (AEC) with shRNAs. Hypoxia (1.5% O2, 24 h) decreased amiloride-sensitive transepithelial Na+-transport, decreased the mRNA expression of α-, β-, and γ-ENaC subunits, and reduced the amount of αβγ-ENaC subunits in the apical plasma membrane. Silencing HIF-2α partially prevented impaired fluid reabsorption in hypoxic rats and prevented the hypoxia-induced decrease in α- but not the βγ-subunits of ENaC protein expression resulting in a less active form of ENaC in hypoxic AEC. Inhibition of alveolar reabsorption also caused pulmonary vasoconstriction in ventilated rats. These results indicate that a HIF-2α-dependent decrease in Na+-transport in hypoxic alveolar epithelium decreases alveolar reabsorption. Because susceptibles to high-altitude pulmonary edema (HAPE) have decreased Na+-transport even in normoxia, inhibition of alveolar reabsorption by hypoxia at high altitude might further impair alveolar gas exchange. Thus, aggravated hypoxemia might further enhance hypoxic pulmonary vasoconstriction and might subsequently cause HAPE.
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Affiliation(s)
- Emel Baloglu
- Department of Pharmacology, Acibadem Mehmet Ali Aydinlar University, School of Medicine, Istanbul, Turkey.,Translational Lung Research Center Heidelberg (TLRC), Heidelberg, Germany
| | | | - Anna Seleninova
- Translational Lung Research Center Heidelberg (TLRC), Heidelberg, Germany
| | - Lena Berg
- Translational Lung Research Center Heidelberg (TLRC), Heidelberg, Germany
| | - Kalpana Velineni
- Translational Lung Research Center Heidelberg (TLRC), Heidelberg, Germany
| | - Ezgi Ermis-Kaya
- Translational Lung Research Center Heidelberg (TLRC), Heidelberg, Germany
| | - Heimo Mairbäurl
- Translational Lung Research Center Heidelberg (TLRC), Heidelberg, Germany.,Translational Pneumology, University Hospital Heidelberg, Heidelberg, Germany
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21
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Gentzsch M, Rossier BC. A Pathophysiological Model for COVID-19: Critical Importance of Transepithelial Sodium Transport upon Airway Infection. FUNCTION 2020; 1:zqaa024. [PMID: 33201937 PMCID: PMC7662147 DOI: 10.1093/function/zqaa024] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 09/29/2020] [Accepted: 10/03/2020] [Indexed: 01/06/2023] Open
Abstract
The Coronavirus Disease 2019 (COVID-19) pandemic remains a serious public health problem and will continue to be until effective drugs and/or vaccines are available. The rational development of drugs critically depends on our understanding of disease mechanisms, that is, the physiology and pathophysiology underlying the function of the organ targeted by the virus. Since the beginning of the pandemic, tireless efforts around the globe have led to numerous publications on the virus, its receptor, its entry into the cell, its cytopathic effects, and how it triggers innate and native immunity but the role of apical sodium transport mediated by the epithelial sodium channel (ENaC) during the early phases of the infection in the airways has received little attention. We propose a pathophysiological model that defines the possible role of ENaC in this process.
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Affiliation(s)
- Martina Gentzsch
- Department of Cell Biology and Physiology, Marsico Lung Institute, University of North Carolina, Chapel Hill, USA
- Department of Pediatric Pulmonology, Marsico Lung Institute, University of North Carolina, Chapel Hill, USA
| | - Bernard C Rossier
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland
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22
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Vega G, Guequén A, Philp AR, Gianotti A, Arzola L, Villalón M, Zegarra-Moran O, Galietta LJ, Mall MA, Flores CA. Lack of Kcnn4 improves mucociliary clearance in muco-obstructive lung disease. JCI Insight 2020; 5:140076. [PMID: 32814712 PMCID: PMC7455130 DOI: 10.1172/jci.insight.140076] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Accepted: 07/08/2020] [Indexed: 12/11/2022] Open
Abstract
Airway mucociliary clearance (MCC) is the main mechanism of lung defense keeping airways free of infection and mucus obstruction. Airway surface liquid volume, ciliary beating, and mucus are central for proper MCC and critically regulated by sodium absorption and anion secretion. Impaired MCC is a key feature of muco-obstructive diseases. The calcium-activated potassium channel KCa.3.1, encoded by Kcnn4, participates in ion secretion, and studies showed that its activation increases Na+ absorption in airway epithelia, suggesting that KCa3.1-induced hyperpolarization was sufficient to drive Na+ absorption. However, its role in airway epithelium is not fully understood. We aimed to elucidate the role of KCa3.1 in MCC using a genetically engineered mouse. KCa3.1 inhibition reduced Na+ absorption in mouse and human airway epithelium. Furthermore, the genetic deletion of Kcnn4 enhanced cilia beating frequency and MCC ex vivo and in vivo. Kcnn4 silencing in the Scnn1b-transgenic mouse (Scnn1btg/+), a model of muco-obstructive lung disease triggered by increased epithelial Na+ absorption, improved MCC, reduced Na+ absorption, and did not change the amount of mucus but did reduce mucus adhesion, neutrophil infiltration, and emphysema. Our data support that KCa3.1 inhibition attenuated muco-obstructive disease in the Scnn1btg/+ mice. K+ channel modulation may be a therapeutic strategy to treat muco-obstructive lung diseases. Silencing the calcium-activated potassium channel KCa.3.1 improves mucociliary clearance in muco-obstructive lung disease by decreasing sodium absorption in the airways.
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Affiliation(s)
| | - Anita Guequén
- Centro de Estudios Científicos, Valdivia, Chile.,Universidad Austral de Chile, Valdivia, Chile
| | - Amber R Philp
- Centro de Estudios Científicos, Valdivia, Chile.,Universidad Austral de Chile, Valdivia, Chile
| | | | - Llilian Arzola
- Departamento de Fisiología, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Manuel Villalón
- Departamento de Fisiología, Pontificia Universidad Católica de Chile, Santiago, Chile
| | | | - Luis Jv Galietta
- Telethon Institute of Genetics and Medicine, Pozzuoli, Italy.,Department of Translational Medical Sciences, University of Naples Federico II, Naples, Italy
| | - Marcus A Mall
- Department of Pediatric Pulmonology, Immunology and Critical Care Medicine, Charité - Universitätsmedizin Berlin, Berlin, Germany.,Berlin Institute of Health, Berlin, Germany.,German Center for Lung Research, Berlin, Germany
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23
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Wichmann L, Althaus M. Evolution of epithelial sodium channels: current concepts and hypotheses. Am J Physiol Regul Integr Comp Physiol 2020; 319:R387-R400. [PMID: 32783689 DOI: 10.1152/ajpregu.00144.2020] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The conquest of freshwater and terrestrial habitats was a key event during vertebrate evolution. Occupation of low-salinity and dry environments required significant osmoregulatory adaptations enabling stable ion and water homeostasis. Sodium is one of the most important ions within the extracellular liquid of vertebrates, and molecular machinery for urinary reabsorption of this electrolyte is critical for the maintenance of body osmoregulation. Key ion channels involved in the fine-tuning of sodium homeostasis in tetrapod vertebrates are epithelial sodium channels (ENaCs), which allow the selective influx of sodium ions across the apical membrane of epithelial cells lining the distal nephron or the colon. Furthermore, ENaC-mediated sodium absorption across tetrapod lung epithelia is crucial for the control of liquid volumes lining the pulmonary surfaces. ENaCs are vertebrate-specific members of the degenerin/ENaC family of cation channels; however, there is limited knowledge on the evolution of ENaC within this ion channel family. This review outlines current concepts and hypotheses on ENaC phylogeny and discusses the emergence of regulation-defining sequence motifs in the context of osmoregulatory adaptations during tetrapod terrestrialization. In light of the distinct regulation and expression of ENaC isoforms in tetrapod vertebrates, we discuss the potential significance of ENaC orthologs in osmoregulation of fishes as well as the putative fates of atypical channel isoforms in mammals. We hypothesize that ancestral proton-sensitive ENaC orthologs might have aided the osmoregulatory adaptation to freshwater environments whereas channel regulation by proteases evolved as a molecular adaptation to lung liquid homeostasis in terrestrial tetrapods.
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Affiliation(s)
- Lukas Wichmann
- Institute for Animal Physiology, Justus Liebig University, Giessen, Germany
| | - Mike Althaus
- Department of Natural Sciences, Bonn-Rhein-Sieg University of Applied Sciences, Rheinbach, Germany
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24
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TMEM16A: An Alternative Approach to Restoring Airway Anion Secretion in Cystic Fibrosis? Int J Mol Sci 2020; 21:ijms21072386. [PMID: 32235608 PMCID: PMC7177896 DOI: 10.3390/ijms21072386] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 03/26/2020] [Accepted: 03/27/2020] [Indexed: 12/18/2022] Open
Abstract
The concept that increasing airway hydration leads to improvements in mucus clearance and lung function in cystic fibrosis has been clinically validated with osmotic agents such as hypertonic saline and more convincingly with cystic fibrosis transmembrane conductance regulator (CFTR) repair therapies. Although rapidly becoming the standard of care in cystic fibrosis (CF), current CFTR modulators do not treat all patients nor do they restore the rate of decline in lung function to normal levels. As such, novel approaches are still required to ensure all with CF have effective therapies. Although CFTR plays a fundamental role in the regulation of fluid secretion across the airway mucosa, there are other ion channels and transporters that represent viable targets for future therapeutics. In this review article we will summarise the current progress with CFTR-independent approaches to restoring mucosal hydration, including epithelial sodium channel (ENaC) blockade and modulators of SLC26A9. A particular emphasis is given to modulation of the airway epithelial calcium-activated chloride channel (CaCC), TMEM16A, as there is controversy regarding whether it should be positively or negatively modulated. This is discussed in light of a recent report describing for the first time bona fide TMEM16A potentiators and their positive effects upon epithelial fluid secretion and mucus clearance.
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25
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Hu M, Bogoyevitch MA, Jans DA. Impact of Respiratory Syncytial Virus Infection on Host Functions: Implications for Antiviral Strategies. Physiol Rev 2020; 100:1527-1594. [PMID: 32216549 DOI: 10.1152/physrev.00030.2019] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Respiratory syncytial virus (RSV) is one of the leading causes of viral respiratory tract infection in infants, the elderly, and the immunocompromised worldwide, causing more deaths each year than influenza. Years of research into RSV since its discovery over 60 yr ago have elucidated detailed mechanisms of the host-pathogen interface. RSV infection elicits widespread transcriptomic and proteomic changes, which both mediate the host innate and adaptive immune responses to infection, and reflect RSV's ability to circumvent the host stress responses, including stress granule formation, endoplasmic reticulum stress, oxidative stress, and programmed cell death. The combination of these events can severely impact on human lungs, resulting in airway remodeling and pathophysiology. The RSV membrane envelope glycoproteins (fusion F and attachment G), matrix (M) and nonstructural (NS) 1 and 2 proteins play key roles in modulating host cell functions to promote the infectious cycle. This review presents a comprehensive overview of how RSV impacts the host response to infection and how detailed knowledge of the mechanisms thereof can inform the development of new approaches to develop RSV vaccines and therapeutics.
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Affiliation(s)
- MengJie Hu
- Department of Biochemistry and Molecular Biology, University of Melbourne, Melbourne, Victoria, Australia; and Department of Biochemistry and Molecular Biology, Monash University, Melbourne, Victoria, Australia
| | - Marie A Bogoyevitch
- Department of Biochemistry and Molecular Biology, University of Melbourne, Melbourne, Victoria, Australia; and Department of Biochemistry and Molecular Biology, Monash University, Melbourne, Victoria, Australia
| | - David A Jans
- Department of Biochemistry and Molecular Biology, University of Melbourne, Melbourne, Victoria, Australia; and Department of Biochemistry and Molecular Biology, Monash University, Melbourne, Victoria, Australia
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26
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Adachi M, Tajima T, Muroya K. Dietary potassium restriction attenuates urinary sodium wasting in the generalized form of pseudohypoaldosteronism type 1. CEN Case Rep 2020; 9:133-137. [PMID: 31900739 DOI: 10.1007/s13730-019-00441-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Accepted: 12/15/2019] [Indexed: 10/25/2022] Open
Abstract
Owing to its rarity and severe nature, the treatment for generalized pseudohypoaldosteronism type 1 (PHA1), a genetic disorder in the epithelial sodium channel (ENaC), is exclusively experience-based. In particular, the usefulness of dietary potassium restriction in PHA1 remains unclear with the absence of theoretical background to elucidate its utility. First, we demonstrated the effect of potassium restriction in a 13-month-old patient with ENaC γ-subunit gene mutations via a retrospective chart review; reduction of daily dietary potassium intake from 40 to 20 mEq induced rapid restoration of volume depletion, as evidenced by weight gain, elevation of the serum sodium level from 133 to 141 mEq/L, decreased urinary sodium excretion, and normalized renin activity. The serum potassium level decreased from 5.6 to 4.5 mEq/L. Next, we attempted to elucidate the pathophysiological basis of the usefulness of potassium restriction, leveraged by the increased knowledge regarding the roles of with-no-lysine kinases (WNKs) in the distal nephron. When potassium is restricted, the WNK signal will turn "on" in the distal nephron via reduction in the intracellular chloride level. Consequently, the sodium reabsorption from the Na+Cl- cotransporter (NCC) in the distal convoluted tubule and possibly from pendrin in the β-intercalated cell will increase. Thus, potassium restriction causes NCC and pendrin to compensate for the non-functional ENaC in the collecting duct. In conclusion, dietary potassium restriction is one of the indispensable treatments for generalized PHA1.
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Affiliation(s)
- Masanori Adachi
- Department of Endocrinology and Metabolism, Kanagawa Children's Medical Center, Mutsukawa, 2-138-4, Minami-ku, Yokohama, 232-8555, Japan.
| | - Toshihiro Tajima
- Department of Pediatrics, Jichi Children's Hospital Medical Center Tochigi, Tochigi, Japan
| | - Koji Muroya
- Department of Endocrinology and Metabolism, Kanagawa Children's Medical Center, Mutsukawa, 2-138-4, Minami-ku, Yokohama, 232-8555, Japan
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27
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Abstract
A spectrum of intrapulmonary airway diseases, for example, cigarette smoke-induced bronchitis, cystic fibrosis, primary ciliary dyskinesia, and non-cystic fibrosis bronchiectasis, can be categorized as "mucoobstructive" airway diseases. A common theme for these diseases appears to be the failure to properly regulate mucus concentration, producing mucus hyperconcentration that slows mucus transport and, importantly, generates plaque/plug adhesion to airway surfaces. These mucus plaques/plugs generate long diffusion distances for oxygen, producing hypoxic niches within adherent airway mucus and subjacent epithelia. Data suggest that concentrated mucus plaques/plugs are proinflammatory, in part mediated by release of IL-1α from hypoxic cells. The infectious component of mucoobstructive diseases may be initiated by anaerobic bacteria that proliferate within the nutrient-rich hypoxic mucus environment. Anaerobes ultimately may condition mucus to provide the environment for a succession to classic airway pathogens, including Staphylococcus aureus, Haemophilus influenzae, and ultimately Pseudomonas aeruginosa. Novel therapies to treat mucoobstructive diseases focus on restoring mucus concentration. Strategies to rehydrate mucus range from the inhalation of osmotically active solutes, designed to draw water into airway surfaces, to strategies designed to manipulate the relative rates of sodium absorption versus chloride secretion to endogenously restore epithelial hydration. Similarly, strategies designed to reduce the mucin burden in the airways, either by reducing mucin production/secretion or by clearing accumulated mucus (e.g., reducing agents), are under development. Thus, the new insights into a unifying process, that is, mucus hyperconcentration, that drives a significant component of the pathogenesis of mucoobstructive diseases promise multiple new therapeutic strategies to aid patients with this syndrome.
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Kuan SP, Liao YSJ, Davis KM, Messer JG, Zubcevic J, Aguirre JI, Reznikov LR. Attenuated Amiloride-Sensitive Current and Augmented Calcium-Activated Chloride Current in Marsh Rice Rat (Oryzomys palustris) Airways. iScience 2019; 19:737-748. [PMID: 31491720 PMCID: PMC6731178 DOI: 10.1016/j.isci.2019.08.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 07/22/2019] [Accepted: 08/05/2019] [Indexed: 11/29/2022] Open
Abstract
Prolonged heat and sea salt aerosols pose a challenge for the mammalian airway, placing the protective airway surface liquid (ASL) at risk for desiccation. Thus, mammals inhabiting salt marshes might have acquired adaptations for ASL regulation. We studied the airways of the rice rat, a rodent that inhabits salt marshes. We discovered negligible Na+ transport through the epithelial sodium channel (ENaC). In contrast, carbachol induced a large Cl- secretory current that was blocked by the calcium-activated chloride channel (CaCC) inhibitor CaCCinhi-A01. Decreased mRNA expression of α, β, and γ ENaC, and increased mRNA expression of the CaCC transmembrane member 16A, distinguished the rice rat airway. Rice rat airway cultures also secreted fluid in response to carbachol and displayed an exaggerated expansion of the ASL volume when challenged with 3.5% NaCl. These data suggest that the rice rat airway might possess unique ion transport adaptations to facilitate survival in the salt marsh environment.
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Affiliation(s)
- Shin-Ping Kuan
- Department of Physiological Sciences, University of Florida, Gainesville, FL 32610, USA
| | - Yan-Shin J Liao
- Department of Physiological Sciences, University of Florida, Gainesville, FL 32610, USA
| | - Katelyn M Davis
- Department of Physiological Sciences, University of Florida, Gainesville, FL 32610, USA
| | - Jonathan G Messer
- Department of Physiological Sciences, University of Florida, Gainesville, FL 32610, USA
| | - Jasenka Zubcevic
- Department of Physiological Sciences, University of Florida, Gainesville, FL 32610, USA
| | - J Ignacio Aguirre
- Department of Physiological Sciences, University of Florida, Gainesville, FL 32610, USA
| | - Leah R Reznikov
- Department of Physiological Sciences, University of Florida, Gainesville, FL 32610, USA.
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van der Wijst J, Belge H, Bindels RJM, Devuyst O. Learning Physiology From Inherited Kidney Disorders. Physiol Rev 2019; 99:1575-1653. [PMID: 31215303 DOI: 10.1152/physrev.00008.2018] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The identification of genes causing inherited kidney diseases yielded crucial insights in the molecular basis of disease and improved our understanding of physiological processes that operate in the kidney. Monogenic kidney disorders are caused by mutations in genes coding for a large variety of proteins including receptors, channels and transporters, enzymes, transcription factors, and structural components, operating in specialized cell types that perform highly regulated homeostatic functions. Common variants in some of these genes are also associated with complex traits, as evidenced by genome-wide association studies in the general population. In this review, we discuss how the molecular genetics of inherited disorders affecting different tubular segments of the nephron improved our understanding of various transport processes and of their involvement in homeostasis, while providing novel therapeutic targets. These include inherited disorders causing a dysfunction of the proximal tubule (renal Fanconi syndrome), with emphasis on epithelial differentiation and receptor-mediated endocytosis, or affecting the reabsorption of glucose, the handling of uric acid, and the reabsorption of sodium, calcium, and magnesium along the kidney tubule.
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Affiliation(s)
- Jenny van der Wijst
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center , Nijmegen , The Netherlands ; Institute of Physiology, University of Zurich , Zurich , Switzerland ; and Division of Nephrology, Institute of Experimental and Clinical Research (IREC), Medical School, Université catholique de Louvain, Brussels, Belgium
| | - Hendrica Belge
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center , Nijmegen , The Netherlands ; Institute of Physiology, University of Zurich , Zurich , Switzerland ; and Division of Nephrology, Institute of Experimental and Clinical Research (IREC), Medical School, Université catholique de Louvain, Brussels, Belgium
| | - René J M Bindels
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center , Nijmegen , The Netherlands ; Institute of Physiology, University of Zurich , Zurich , Switzerland ; and Division of Nephrology, Institute of Experimental and Clinical Research (IREC), Medical School, Université catholique de Louvain, Brussels, Belgium
| | - Olivier Devuyst
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center , Nijmegen , The Netherlands ; Institute of Physiology, University of Zurich , Zurich , Switzerland ; and Division of Nephrology, Institute of Experimental and Clinical Research (IREC), Medical School, Université catholique de Louvain, Brussels, Belgium
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30
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Wichmann L, Dulai JS, Marles-Wright J, Maxeiner S, Szczesniak PP, Manzini I, Althaus M. An extracellular acidic cleft confers profound H +-sensitivity to epithelial sodium channels containing the δ-subunit in Xenopus laevis. J Biol Chem 2019; 294:12507-12520. [PMID: 31248986 DOI: 10.1074/jbc.ra119.008255] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2019] [Revised: 06/27/2019] [Indexed: 11/06/2022] Open
Abstract
The limited sodium availability of freshwater and terrestrial environments was a major physiological challenge during vertebrate evolution. The epithelial sodium channel (ENaC) is present in the apical membrane of sodium-absorbing vertebrate epithelia and evolved as part of a machinery for efficient sodium conservation. ENaC belongs to the degenerin/ENaC protein family and is the only member that opens without an external stimulus. We hypothesized that ENaC evolved from a proton-activated sodium channel present in ionocytes of freshwater vertebrates and therefore investigated whether such ancestral traits are present in ENaC isoforms of the aquatic pipid frog Xenopus laevis Using whole-cell and single-channel electrophysiology of Xenopus oocytes expressing ENaC isoforms assembled from αβγ- or δβγ-subunit combinations, we demonstrate that Xenopus δβγ-ENaC is profoundly activated by extracellular acidification within biologically relevant ranges (pH 8.0-6.0). This effect was not observed in Xenopus αβγ-ENaC or human ENaC orthologs. We show that protons interfere with allosteric ENaC inhibition by extracellular sodium ions, thereby increasing the probability of channel opening. Using homology modeling of ENaC structure and site-directed mutagenesis, we identified a cleft region within the extracellular loop of the δ-subunit that contains several acidic amino acid residues that confer proton-sensitivity and enable allosteric inhibition by extracellular sodium ions. We propose that Xenopus δβγ-ENaC can serve as a model for investigating ENaC transformation from a proton-activated toward a constitutively-active ion channel. Such transformation might have occurred during the evolution of tetrapod vertebrates to enable bulk sodium absorption during the water-to-land transition.
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Affiliation(s)
- Lukas Wichmann
- School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne NE1 7RU, United Kingdom; Institute of Animal Physiology, Department of Animal Physiology and Molecular Biomedicine, Justus-Liebig University Giessen, 35390 Giessen, Germany
| | - Jasdip Singh Dulai
- School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne NE1 7RU, United Kingdom
| | - Jon Marles-Wright
- School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne NE1 7RU, United Kingdom
| | - Stephan Maxeiner
- Institute of Anatomy and Cell Biology, Saarland University, 66421 Homburg, Germany
| | - Pawel Piotr Szczesniak
- Department of Medicine, Haematology/Oncology, Johann-Wolfgang-Goethe University Frankfurt, 60323 Frankfurt, Germany
| | - Ivan Manzini
- Institute of Animal Physiology, Department of Animal Physiology and Molecular Biomedicine, Justus-Liebig University Giessen, 35390 Giessen, Germany
| | - Mike Althaus
- School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne NE1 7RU, United Kingdom.
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Abstract
Renal tubular acidosis should be suspected in poorly thriving young children with hyperchloremic and hypokalemic normal anion gap metabolic acidosis, with/without syndromic features. Further workup is needed to determine the type of renal tubular acidosis and the presumed etiopathogenesis, which informs treatment choices and prognosis. The risk of nephrolithiasis and calcinosis is linked to the presence (proximal renal tubular acidosis, negligible stone risk) or absence (distal renal tubular acidosis, high stone risk) of urine citrate excretion. New formulations of slow-release alkali and potassium combination supplements are being tested that are expected to simplify treatment and lead to sustained acidosis correction.
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Affiliation(s)
- Robert Todd Alexander
- Department of Pediatrics and Physiology, Stollery Children's Hospital, 11405-87 Avenue, Edmonton, Alberta T6G 1C9, Canada
| | - Martin Bitzan
- Division of Nephrology, Department of Pediatrics, The Montreal Children's Hospital, McGill University Health Centre, Room B RC.6651, Montreal, Quebec H4A 3J1, Canada; Al Jalila Children's Hospital, Al Jadaf PO Box 7662, Dubai, UAE.
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32
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Li M, Keenan CR, Lopez-Campos G, Mangum JE, Chen Q, Prodanovic D, Xia YC, Langenbach SY, Harris T, Hofferek V, Reid GE, Stewart AG. A Non-canonical Pathway with Potential for Safer Modulation of Transforming Growth Factor-β1 in Steroid-Resistant Airway Diseases. iScience 2019; 12:232-246. [PMID: 30711747 PMCID: PMC6360516 DOI: 10.1016/j.isci.2019.01.023] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Revised: 03/27/2018] [Accepted: 01/15/2019] [Indexed: 12/15/2022] Open
Abstract
Impaired therapeutic responses to anti-inflammatory glucocorticoids (GC) in chronic respiratory diseases are partly attributable to interleukins and transforming growth factor β1 (TGF-β1). However, previous efforts to prevent induction of GC insensitivity by targeting established canonical and non-canonical TGF-β1 pathways have been unsuccessful. Here we elucidate a TGF-β1 signaling pathway modulating GC activity that involves LIM domain kinase 2-mediated phosphorylation of cofilin1. Severe, steroid-resistant asthmatic airway epithelium showed increased levels of immunoreactive phospho-cofilin1. Phospho-cofilin1 was implicated in the activation of phospholipase D (PLD) to generate the effector(s) (lyso)phosphatidic acid, which mimics the TGF-β1-induced GC insensitivity. TGF-β1 induction of the nuclear hormone receptor corepressor, SMRT (NCOR2), was dependent on cofilin1 and PLD activities. Depletion of SMRT prevented GC insensitivity. This pathway for GC insensitivity offers several promising drug targets that potentially enable a safer approach to the modulation of TGF-β1 in chronic inflammatory diseases than is afforded by global TGF-β1 inhibition. TGF-β1 extensively impairs GC activity Phospho-cofilin1 is a key link in TGF-β1 signaling cascade subserving GC insensitivity Phospho-cofilin1-activated phospholipase D (PLD) reduces GC activity SMRT induction downstream of PLD mediates TGF-β1 impairment of GC activity
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Affiliation(s)
- Meina Li
- Department of Pharmacology & Therapeutics, School of Biomedical Science, University of Melbourne, Parkville, VIC 3010, Australia
| | - Christine R Keenan
- Department of Pharmacology & Therapeutics, School of Biomedical Science, University of Melbourne, Parkville, VIC 3010, Australia
| | - Guillermo Lopez-Campos
- Health and Biomedical Informatics Centre, Melbourne Medical School, University of Melbourne, Parkville, VIC 3010, Australia; Centre for Experimental Medicine, Queen's University of Belfast, Belfast BT9 7BL, UK
| | - Jonathan E Mangum
- Department of Pharmacology & Therapeutics, School of Biomedical Science, University of Melbourne, Parkville, VIC 3010, Australia
| | - Qianyu Chen
- Department of Pharmacology & Therapeutics, School of Biomedical Science, University of Melbourne, Parkville, VIC 3010, Australia
| | - Danica Prodanovic
- Department of Pharmacology & Therapeutics, School of Biomedical Science, University of Melbourne, Parkville, VIC 3010, Australia
| | - Yuxiu C Xia
- Department of Pharmacology & Therapeutics, School of Biomedical Science, University of Melbourne, Parkville, VIC 3010, Australia
| | - Shenna Y Langenbach
- Department of Pharmacology & Therapeutics, School of Biomedical Science, University of Melbourne, Parkville, VIC 3010, Australia
| | - Trudi Harris
- Department of Pharmacology & Therapeutics, School of Biomedical Science, University of Melbourne, Parkville, VIC 3010, Australia
| | - Vinzenz Hofferek
- Max Plank Institute of Molecular Plant Physiology, Potsdam, Germany; School of Chemistry, University of Melbourne, Parkville, VIC 3010, Australia
| | - Gavin E Reid
- School of Chemistry, University of Melbourne, Parkville, VIC 3010, Australia; Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, VIC 3010, Australia; Bio21 Molecular Science and Biotechnology Institute. University of Melbourne, Parkville, VIC 3010, Australia
| | - Alastair G Stewart
- Department of Pharmacology & Therapeutics, School of Biomedical Science, University of Melbourne, Parkville, VIC 3010, Australia; ARC Centre for Personalised Therapeutics Technologies, Parkville, VIC, Australia.
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33
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Shei RJ, Peabody JE, Kaza N, Rowe SM. The epithelial sodium channel (ENaC) as a therapeutic target for cystic fibrosis. Curr Opin Pharmacol 2018; 43:152-165. [PMID: 30340955 PMCID: PMC6294660 DOI: 10.1016/j.coph.2018.09.007] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Accepted: 09/11/2018] [Indexed: 01/28/2023]
Abstract
Cystic fibrosis (CF) is a monogenic disease caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. CFTR dysfunction is characterized by abnormal mucociliary transport due to a dehydrated airway surface liquid (ASL) and hyperviscous mucus, among other pathologies of host defense. ASL depletion is caused by the absence of CFTR mediated chloride secretion along with continued activity of the epithelial sodium channel (ENaC) activity, which can also be affected by CFTR mediated anion conductance. Therefore, ENaC has been proposed as a therapeutic target to ameliorate ASL dehydration and improve mucus transport. Inhibition of ENaC has been shown to restore ASL hydration and enhance mucociliary transport in induced models of CF lung disease. To date, no therapy inhibiting ENaC has successfully translated to clinical efficacy, in part due to concerns regarding off-target effects, systemic exposure, durability of effect, and adverse effects. Recent efforts have been made to develop novel, rationally designed therapeutics to produce-specific, long-lasting inhibition of ENaC activity in the airways while simultaneously minimizing off target fluid transport effects, systemic exposure and side effects. Such approaches comprise next-generation small molecule direct inhibitors, indirect channel-activating protease inhibitors, synthetic peptide analogs, and oligonucleotide-based therapies. These novel therapeutics represent an exciting step forward in the development of ENaC-directed therapies for CF.
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Affiliation(s)
- Ren-Jay Shei
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA; The Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Jacelyn E Peabody
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA; Medical Scientist (MD/PhD) Training Program, University of Alabama at Birmingham, Birmingham, AL, USA; The Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Niroop Kaza
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA; The Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Steven M Rowe
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA; Department of Pediatrics, University of Alabama at Birmingham, Birmingham, AL, USA; Department of Cell Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL, USA; The Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham, Birmingham, AL, USA.
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34
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Mucociliary Clearance in Mice Measured by Tracking Trans-tracheal Fluorescence of Nasally Aerosolized Beads. Sci Rep 2018; 8:14744. [PMID: 30282981 PMCID: PMC6170422 DOI: 10.1038/s41598-018-33053-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Accepted: 09/19/2018] [Indexed: 12/15/2022] Open
Abstract
Mucociliary clearance (MCC) is the first line of defense in clearing airways. In genetically engineered mice, each component of this system (ciliary beat, mucus, airway surface hydration) can be studied separately to determine its contribution to MCC. Because MCC is difficult to measure in mice, MCC measurements are often omitted from these studies. We report a simple method to measure MCC in mice involving nasal inhalation of aerosolized fluorescent beads and trans-tracheal bead tracking. This method has a number of advantages over existing methods: (1) a small volume of liquid is deposited thus minimally disturbing the airway surface; (2) bead behavior on airways can be visualized; (3) useful for adult or neonatal mice; (4) the equipment is relatively inexpensive and easily obtainable. The type of anesthetic had no significant effect on the rate of MCC, but overloading the airways with beads significantly decreased MCC. In addition, the rate of bead transport was not different in alive (3.11 mm/min) vs recently euthanized mice (3.10 mm/min). A 5-min aerosolization of beads in a solution containing UTP significantly increased the rate of MCC, demonstrating that our method would be of value in testing the role of various pharmacological agents on MCC.
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35
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Karrasch S, Radtke T, Simon M, Kronseder A, Dressel H, Jörres RA, Ochmann U. Acute effects of hypertonic saline inhalation on nitric oxide pulmonary diffusing capacity in healthy adults. Respir Physiol Neurobiol 2018; 258:40-46. [PMID: 30261306 DOI: 10.1016/j.resp.2018.09.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Revised: 09/13/2018] [Accepted: 09/21/2018] [Indexed: 11/26/2022]
Abstract
We investigated acute effects of inhalation of hypertonic saline solution (HSS) and oxygen (O2, control exposure) on pulmonary diffusing capacity for nitric oxide (DLNO) and carbon monoxide (DLCO). In a randomized crossover study, 20 healthy, non-smoking subjects were allocated to short-term inhalation of HSS or O2. Spirometry [(forced expiratory volume in 1 s (FEV1) and forced vital capacity (FVC)] and combined single-breath DLNO-DLCO measurements were performed before and immediately after inhalation of either HSS or O2. Percent changes were presented as median values (interquartile range). After HSS inhalation, DLNO, FEV1 and FVC were decreased by -3.0% (-7.3, 0.5), -3.1% (-4.2, -1.6) and -1.2% (-3.3, 0.6), respectively (all P < 0.05), without significant effect on DLCO. No changes in spirometry and diffusing capacity were observed following O2 inhalation. Acute inhalation of HSS causes a slight decrease in membrane conductance, probably as a result of fluid imbalance at the alveolar surface and interstitial fluid accumulation, both of which could impair gas exchange.
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Affiliation(s)
- S Karrasch
- Institute and Outpatient Clinic for Occupational, Social and Environmental Medicine, Inner City Clinic, University Hospital of Munich, Ludwig-Maximilians-Universität, Munich, Germany; Institute of Epidemiology, Helmholtz Zentrum München - German Research Center for Environmental Health, Neuherberg, Germany; Comprehensive Pneumology Center Munich (CPC-M), Member of the German Center for Lung Research, Munich, Neuherberg, Germany
| | - T Radtke
- Epidemiology, Biostatistics and Prevention Institute, University of Zurich, Zurich, Switzerland; Division of Occupational and Environmental Medicine, University of Zurich and University Hospital Zurich, Zurich, Switzerland.
| | - M Simon
- Institute and Outpatient Clinic for Occupational, Social and Environmental Medicine, Inner City Clinic, University Hospital of Munich, Ludwig-Maximilians-Universität, Munich, Germany
| | - A Kronseder
- Institute and Outpatient Clinic for Occupational, Social and Environmental Medicine, Inner City Clinic, University Hospital of Munich, Ludwig-Maximilians-Universität, Munich, Germany
| | - H Dressel
- Institute and Outpatient Clinic for Occupational, Social and Environmental Medicine, Inner City Clinic, University Hospital of Munich, Ludwig-Maximilians-Universität, Munich, Germany; Epidemiology, Biostatistics and Prevention Institute, University of Zurich, Zurich, Switzerland; Division of Occupational and Environmental Medicine, University of Zurich and University Hospital Zurich, Zurich, Switzerland
| | - R A Jörres
- Institute and Outpatient Clinic for Occupational, Social and Environmental Medicine, Inner City Clinic, University Hospital of Munich, Ludwig-Maximilians-Universität, Munich, Germany; Comprehensive Pneumology Center Munich (CPC-M), Member of the German Center for Lung Research, Munich, Neuherberg, Germany
| | - U Ochmann
- Institute and Outpatient Clinic for Occupational, Social and Environmental Medicine, Inner City Clinic, University Hospital of Munich, Ludwig-Maximilians-Universität, Munich, Germany
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36
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Noreng S, Bharadwaj A, Posert R, Yoshioka C, Baconguis I. Structure of the human epithelial sodium channel by cryo-electron microscopy. eLife 2018; 7:39340. [PMID: 30251954 PMCID: PMC6197857 DOI: 10.7554/elife.39340] [Citation(s) in RCA: 105] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Accepted: 09/18/2018] [Indexed: 12/11/2022] Open
Abstract
The epithelial sodium channel (ENaC), a member of the ENaC/DEG superfamily, regulates Na+ and water homeostasis. ENaCs assemble as heterotrimeric channels that harbor protease-sensitive domains critical for gating the channel. Here, we present the structure of human ENaC in the uncleaved state determined by single-particle cryo-electron microscopy. The ion channel is composed of a large extracellular domain and a narrow transmembrane domain. The structure reveals that ENaC assembles with a 1:1:1 stoichiometry of α:β:γ subunits arranged in a counter-clockwise manner. The shape of each subunit is reminiscent of a hand with key gating domains of a 'finger' and a 'thumb.' Wedged between these domains is the elusive protease-sensitive inhibitory domain poised to regulate conformational changes of the 'finger' and 'thumb'; thus, the structure provides the first view of the architecture of inhibition of ENaC.
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Affiliation(s)
- Sigrid Noreng
- Department of Biochemistry & Molecular Biology, Oregon Health and Science University, Portland, United States
| | - Arpita Bharadwaj
- Vollum Institute, Oregon Health and Science University, Portland, United States
| | - Richard Posert
- Department of Biochemistry & Molecular Biology, Oregon Health and Science University, Portland, United States
| | - Craig Yoshioka
- Department of Biomedical Engineering, Oregon Health and Science University, Portland, United States
| | - Isabelle Baconguis
- Vollum Institute, Oregon Health and Science University, Portland, United States
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Moore PJ, Tarran R. The epithelial sodium channel (ENaC) as a therapeutic target for cystic fibrosis lung disease. Expert Opin Ther Targets 2018; 22:687-701. [PMID: 30028216 DOI: 10.1080/14728222.2018.1501361] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
INTRODUCTION Cystic fibrosis is an autosomal recessive disorder caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene that codes for the CFTR anion channel. In the absence of functional CFTR, the epithelial Na+ channel is also dysregulated. Airway surface liquid (ASL) hydration is maintained by a balance between epithelial sodium channel (ENaC)-led Na+ absorption and CFTR-dependent anion secretion. This finely tuned homeostatic mechanism is required to maintain sufficient airway hydration to permit the efficient mucus clearance necessary for a sterile lung environment. In CF airways, the lack of CFTR and increased ENaC activity lead to ASL/mucus dehydration that causes mucus obstruction, neutrophilic infiltration, and chronic bacterial infection. Rehydration of ASL/mucus in CF airways can be achieved by inhibiting Na+ absorption with pharmacological inhibitors of ENaC. Areas covered: In this review, we discuss ENaC structure and function and its role in CF lung disease and focus on ENaC inhibition as a potential therapeutic target to rehydrate CF mucus. We also discuss the failure of the first generation of pharmacological inhibitors of ENaC and recent alternate strategies to attenuate ENaC activity in the CF lung. Expert opinion: ENaC is an attractive therapeutic target to rehydrate CF ASL that may serve as a monotherapy or function in parallel with other treatments. Given the increased number of strategies being employed to inhibit ENaC, this is an exciting and optimistic time to be in this field.
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Affiliation(s)
- Patrick J Moore
- a Marsico Lung Institute , University of North Carolina , Chapel Hill , NC , USA
| | - Robert Tarran
- a Marsico Lung Institute , University of North Carolina , Chapel Hill , NC , USA.,b Department of Cell Biology & Physiology , University of North Carolina , Chapel Hill , NC , USA
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38
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Van Iterson EH, Snyder EM, Johnson BD. Alveolar air and oxidative metabolic demand during exercise in healthy adults: the role of single-nucleotide polymorphisms of the β2AR gene. Physiol Rep 2018; 5:5/20/e13476. [PMID: 29061864 PMCID: PMC5661237 DOI: 10.14814/phy2.13476] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2017] [Accepted: 09/17/2017] [Indexed: 11/30/2022] Open
Abstract
The predominating β‐adrenergic receptor subtype expressed on human alveolar tissue is the β2AR. The homozygous arginine (Arg16Arg) single‐nucleotide polymorphism (SNP) at codon 16 of the β2AR gene has been associated with abnormal β2AR function accompanied by decreased resting alveolar‐capillary membrane gas‐transfer in certain healthy adults. Although not previously studied in the context of the β2AR gene, pulmonary gas‐transfer is also influenced by alveolar volume (VA) and with it the availability of alveolar surface area, particularly during exercise. Small VA implies less alveolar surface area available for O2 transport. We tested the following hypothesis in healthy adults during exercise: compared with Gly16Gly and Arg16Gly β2AR genotypes, Arg16Arg will demonstrate reduced VA and ventilation (V̇A) relative to V̇E and oxidative metabolic demand. Age‐ BMI‐ and gender‐matched groups of Arg16Arg (N = 16), Gly16Gly (N = 31), and Arg16Gly (N = 17) performed consecutive low (9‐min, 40%‐peak workload) and moderate (9‐min, 75%‐peak workload) intensity exercise. We derived VA and V̇A using “ideal” alveolar equations via arterialized gases combined with breath‐by‐breath ventilation and gas‐exchange measurements; whereas steady‐state V̇O2 was used in metabolic equations to derive exercise economy (EC = workload÷V̇O2). Variables at rest did not differ across β2AR genotype. Strongest β2AR genotype effects occurred during moderate exercise. Accordingly, while V̇E did not differ across genotype (P > 0.05), decreased in Arg16Arg versus Arg16Gly and Gly16Gly were V̇O2 (1110 ± 263, 1269 ± 221, 1300 ± 319 mL/(min·m2), respectively, both P < 0.05), V̇A (59 ± 21, 70 ± 16, 70 ± 21 L/min, respectively, both P < 0.05), and VA (1.43 ± 0.37, 1.95 ± 0.61, 1.93 ± 0.65 L, respectively, both P < 0.05). Also reduced was EC in Arg16Arg versus Arg16Gly (P < 0.05) and Gly16Gly (P > 0.05) (1.81 ± 0.23, 1.99 ± 0.30, and 1.94 ± 0.26 kcal/(L·m2), respectively). Compared with Gly16Gly and Arg16Gly genotypes, these data suggest the Arg16Arg β2AR genotype plays a role in the loss of oxidative metabolic efficiency coupled with an inadaptive VA and, hence, smaller alveolar surface area available for O2 transport during submaximal exercise in healthy adults.
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Affiliation(s)
- Erik H Van Iterson
- Department of Cardiovascular Medicine, Mayo Clinic College of Medicine, Rochester, Minnesota
| | - Eric M Snyder
- Department of Kinesiology, University of Minnesota, Minneapolis, Minnesota
| | - Bruce D Johnson
- Department of Cardiovascular Medicine, Mayo Clinic College of Medicine, Rochester, Minnesota
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Terryah ST, Fellner RC, Ahmad S, Moore PJ, Reidel B, Sesma JI, Kim CS, Garland AL, Scott DW, Sabater JR, Carpenter J, Randell SH, Kesimer M, Abraham WM, Arendshorst WJ, Tarran R. Evaluation of a SPLUNC1-derived peptide for the treatment of cystic fibrosis lung disease. Am J Physiol Lung Cell Mol Physiol 2017; 314:L192-L205. [PMID: 28982737 DOI: 10.1152/ajplung.00546.2016] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
In cystic fibrosis (CF) lungs, epithelial Na+ channel (ENaC) hyperactivity causes a reduction in airway surface liquid volume, leading to decreased mucocilliary clearance, chronic bacterial infection, and lung damage. Inhibition of ENaC is an attractive therapeutic option. However, ENaC antagonists have failed clinically because of off-target effects in the kidney. The S18 peptide is a naturally occurring short palate lung and nasal epithelial clone 1 (SPLUNC1)-derived ENaC antagonist that restores airway surface liquid height for up to 24 h in CF human bronchial epithelial cultures. However, its efficacy and safety in vivo are unknown. To interrogate the potential clinical efficacy of S18, we assessed its safety and efficacy using human airway cultures and animal models. S18-mucus interactions were tested using superresolution microscopy, quartz crystal microbalance with dissipation, and confocal microscopy. Human and murine airway cultures were used to measure airway surface liquid height. Off-target effects were assessed in conscious mice and anesthetized rats. Morbidity and mortality were assessed in the β-ENaC-transgenic (Tg) mouse model. Restoration of normal mucus clearance was measured in cystic fibrosis transmembrane conductance regulator inhibitor 172 [CFTR(inh)-172]-challenged sheep. We found that S18 does not interact with mucus and rapidly penetrated dehydrated CF mucus. Compared with amiloride, an early generation ENaC antagonist, S18 displayed a superior ability to slow airway surface liquid absorption, reverse CFTR(inh)-172-induced reduction of mucus transport, and reduce morbidity and mortality in the β-ENaC-Tg mouse, all without inducing any detectable signs of renal toxicity. These data suggest that S18 is the first naturally occurring ENaC antagonist to show improved preclinical efficacy in animal models of CF with no signs of renal toxicity.
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Affiliation(s)
- Shawn T Terryah
- Cystic Fibrosis Center/Marsico Lung Institute, The University of North Carolina at Chapel Hill , Chapel Hill, North Carolina
| | - Robert C Fellner
- Cystic Fibrosis Center/Marsico Lung Institute, The University of North Carolina at Chapel Hill , Chapel Hill, North Carolina
| | - Saira Ahmad
- Cystic Fibrosis Center/Marsico Lung Institute, The University of North Carolina at Chapel Hill , Chapel Hill, North Carolina
| | - Patrick J Moore
- Cystic Fibrosis Center/Marsico Lung Institute, The University of North Carolina at Chapel Hill , Chapel Hill, North Carolina
| | - Boris Reidel
- Cystic Fibrosis Center/Marsico Lung Institute, The University of North Carolina at Chapel Hill , Chapel Hill, North Carolina
| | | | - Christine S Kim
- Cystic Fibrosis Center/Marsico Lung Institute, The University of North Carolina at Chapel Hill , Chapel Hill, North Carolina
| | - Alaina L Garland
- Cystic Fibrosis Center/Marsico Lung Institute, The University of North Carolina at Chapel Hill , Chapel Hill, North Carolina
| | | | - Juan R Sabater
- Department of Research, Mount Sinai Medical Center , Miami Beach, Florida
| | - Jerome Carpenter
- Cystic Fibrosis Center/Marsico Lung Institute, The University of North Carolina at Chapel Hill , Chapel Hill, North Carolina
| | - Scott H Randell
- Cystic Fibrosis Center/Marsico Lung Institute, The University of North Carolina at Chapel Hill , Chapel Hill, North Carolina.,Cell Biology and Physiology, The University of North Carolina at Chapel Hill , Chapel Hill, North Carolina
| | - Mehmet Kesimer
- Cystic Fibrosis Center/Marsico Lung Institute, The University of North Carolina at Chapel Hill , Chapel Hill, North Carolina
| | - William M Abraham
- Department of Research, Mount Sinai Medical Center , Miami Beach, Florida
| | - William J Arendshorst
- Cell Biology and Physiology, The University of North Carolina at Chapel Hill , Chapel Hill, North Carolina
| | - Robert Tarran
- Cystic Fibrosis Center/Marsico Lung Institute, The University of North Carolina at Chapel Hill , Chapel Hill, North Carolina.,Cell Biology and Physiology, The University of North Carolina at Chapel Hill , Chapel Hill, North Carolina
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Wheatley CM, Baker SE, Taylor BJ, Keller-Ross ML, Chase SC, Carlson AR, Wentz RJ, Snyder EM, Johnson BD. Influence of Inhaled Amiloride on Lung Fluid Clearance in Response to Normobaric Hypoxia in Healthy Individuals. High Alt Med Biol 2017; 18:343-354. [PMID: 28876128 DOI: 10.1089/ham.2017.0032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Wheatley, Courtney M., Sarah E. Baker, Bryan J. Taylor, Manda L. Keller-Ross, Steven C. Chase, Alex R. Carlson, Robert J. Wentz, Eric M. Snyder, and Bruce D. Johnson. Influence of inhaled amiloride on lung fluid clearance in response to normobaric hypoxia in healthy individuals. High Alt Med Biol 18:343-354, 2017. AIM To investigate the role of epithelial sodium channels (ENaC) on lung fluid clearance in response to normobaric hypoxia, 20 healthy subjects were exposed to 15 hours of hypoxia (fraction of inspired oxygen [FiO2] = 12.5%) on two randomized occasions: (1) inhaled amiloride (A) (1.5 mg/5 mL saline); and (2) inhaled saline placebo (P). Changes in lung fluid were assessed through chest computed tomography (CT) for lung tissue volume (TV), and the diffusion capacity of the lungs for carbon monoxide (DLCO) and nitric oxide (DLNO) for pulmonary capillary blood volume (VC). Extravascular lung water (EVLW) was derived as TV-VC and changes in the CT attenuation distribution histograms were reviewed. RESULTS Normobaric hypoxia caused (1) a reduction in EVLW (change from baseline for A vs. P, -8.5% ± 3.8% vs. -7.9% ± 5.2%, p < 0.05), (2) an increase in VC (53.6% ± 28.9% vs. 53.9% ± 52.3%, p < 0.05), (3) a small increase in DLCO (9.6% ± 29.3% vs. 9.9% ± 23.9%, p > 0.05), and (4) CT attenuation distribution became more negative, leftward skewed, and kurtotic (p < 0.05). CONCLUSION Acute normobaric hypoxia caused a reduction in lung fluid that was unaffected by ENaC inhibition through inhaled amiloride. Although possible amiloride-sensitive ENaC may not be necessary to maintain lung fluid balance in response to hypoxia, it is more probable that normobaric hypoxia promotes lung fluid clearance rather than accumulation for the majority of healthy individuals. The observed reduction in interstitial lung fluid means alveolar fluid clearance may not have been challenged.
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Affiliation(s)
- Courtney M Wheatley
- 1 Department of Pharmaceutical Science, University of Arizona , Tucson, Arizona
| | - Sarah E Baker
- 1 Department of Pharmaceutical Science, University of Arizona , Tucson, Arizona
| | - Bryan J Taylor
- 2 Division of Cardiovascular Diseases, Mayo Clinic , Rochester, Minnesota
| | | | - Steven C Chase
- 2 Division of Cardiovascular Diseases, Mayo Clinic , Rochester, Minnesota
| | - Alex R Carlson
- 2 Division of Cardiovascular Diseases, Mayo Clinic , Rochester, Minnesota
| | - Robert J Wentz
- 2 Division of Cardiovascular Diseases, Mayo Clinic , Rochester, Minnesota
| | - Eric M Snyder
- 1 Department of Pharmaceutical Science, University of Arizona , Tucson, Arizona
| | - Bruce D Johnson
- 2 Division of Cardiovascular Diseases, Mayo Clinic , Rochester, Minnesota
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41
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Tajima T, Morikawa S, Nakamura A. Clinical features and molecular basis of pseudohypoaldosteronism type 1. Clin Pediatr Endocrinol 2017; 26:109-117. [PMID: 28804203 PMCID: PMC5537208 DOI: 10.1297/cpe.26.109] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/04/2017] [Accepted: 02/25/2017] [Indexed: 12/17/2022] Open
Abstract
Pseudohypoaldosteronism (PHA) type 1 is a disease showing mineralocorticoid resistance in the kidney and/or other mineralocorticoid target tissues. Patients with PHA1 present very high plasma aldosterone and renin levels, but they develop excessive salt wasting. There are three types of PHA1. The systemic form of PHA1 is inherited in an autosomal recessive manner and causes severe life-long salt loss in multiple target tissues, such as sweat glands, salivary glands, the colonic epithelium, and the lung. In the systemic form of PHA1, life-long salt supplementation is necessary. The second type is the renal form, where aldosterone resistance is shown only in the kidney, and its inheritance is autosomal dominant. In the renal form of PHA1, salt supplementation generally becomes unnecessary by 1-3 yr of age. The third type is the secondary PHA1, which is strongly associated with urinary tract infections and/or urinary tract malformations. This review summarizes the clinical features and molecular basis of PHA1. Understanding of its pathogenesis can be helpful for the early diagnosis and clinical care of affected children with PHA1.
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Affiliation(s)
- Toshihiro Tajima
- Department of Pediatrics, Jichi Children's Hospital Medical Center Tochigi, Tochigi, Japan
| | - Shuntaro Morikawa
- Department of Pediatrics, Hokkaido University School of Medicine, Hokkaido, Japan
| | - Akie Nakamura
- Department of Molecular Endocrinology, National Research Institute for Child Health and Development, Tokyo, Japan
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Wynne BM, Zou L, Linck V, Hoover RS, Ma HP, Eaton DC. Regulation of Lung Epithelial Sodium Channels by Cytokines and Chemokines. Front Immunol 2017; 8:766. [PMID: 28791006 PMCID: PMC5524836 DOI: 10.3389/fimmu.2017.00766] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2017] [Accepted: 06/16/2017] [Indexed: 12/20/2022] Open
Abstract
Acute lung injury leading to acute respiratory distress (ARDS) is a global health concern. ARDS patients have significant pulmonary inflammation leading to flooding of the pulmonary alveoli. This prevents normal gas exchange with consequent hypoxemia and causes mortality. A thin fluid layer in the alveoli is normal. The maintenance of this thin layer results from fluid movement out of the pulmonary capillaries into the alveolar interstitium driven by vascular hydrostatic pressure and then through alveolar tight junctions. This is then balanced by fluid reabsorption from the alveolar space mediated by transepithelial salt and water transport through alveolar cells. Reabsorption is a two-step process: first, sodium enters via sodium-permeable channels in the apical membranes of alveolar type 1 and 2 cells followed by active extrusion of sodium into the interstitium by the basolateral Na+, K+-ATPase. Anions follow the cationic charge gradient and water follows the salt-induced osmotic gradient. The proximate cause of alveolar flooding is the result of a failure to reabsorb sufficient salt and water or a failure of the tight junctions to prevent excessive movement of fluid from the interstitium to alveolar lumen. Cytokine- and chemokine-induced inflammation can have a particularly profound effect on lung sodium transport since they can alter both ion channel and barrier function. Cytokines and chemokines affect alveolar amiloride-sensitive epithelial sodium channels (ENaCs), which play a crucial role in sodium transport and fluid reabsorption in the lung. This review discusses the regulation of ENaC via local and systemic cytokines during inflammatory disease and the effect on lung fluid balance.
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Affiliation(s)
- Brandi M Wynne
- Department of Medicine, Nephrology, Emory University, Atlanta, GA, United States.,Department of Physiology, Emory University, Atlanta, GA, United States.,The Center for Cell and Molecular Signaling, Emory University, Atlanta, GA, United States
| | - Li Zou
- Department of Physiology, Emory University, Atlanta, GA, United States
| | - Valerie Linck
- Department of Physiology, Emory University, Atlanta, GA, United States
| | - Robert S Hoover
- Department of Medicine, Nephrology, Emory University, Atlanta, GA, United States.,Department of Physiology, Emory University, Atlanta, GA, United States.,Research Service, Atlanta Veteran's Administration Medical Center, Decatur, GA, United States
| | - He-Ping Ma
- Department of Physiology, Emory University, Atlanta, GA, United States.,The Center for Cell and Molecular Signaling, Emory University, Atlanta, GA, United States
| | - Douglas C Eaton
- Department of Physiology, Emory University, Atlanta, GA, United States.,The Center for Cell and Molecular Signaling, Emory University, Atlanta, GA, United States
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43
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Abstract
The epithelial Na+ channel (ENaC) is a key regulator of the volume of airway surface liquid (ASL) and is found in the human airway epithelium. In cystic fibrosis (CF), Na+ hyperabsorption through ENaC, in the absence of cystic fibrosis transmembrane conductance regulator mediated anion secretion, results in the dehydration of respiratory secretions and the impairment of mucociliary clearance. The hypothesis of utilizing an ENaC blocking molecule to facilitate restoration of the airway surface liquid volume sufficiently to allow normal mucociliary clearance is of interest in the management of lung disease in CF patients. This review summarizes the published patent applications from 2014 to the end of 2016 that claim approaches to inhibit the function of ENaC for the treatment of CF.
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44
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Zennaro MC, Fernandes-Rosa F. 30 YEARS OF THE MINERALOCORTICOID RECEPTOR: Mineralocorticoid receptor mutations. J Endocrinol 2017; 234:T93-T106. [PMID: 28348114 DOI: 10.1530/joe-17-0089] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Accepted: 03/27/2017] [Indexed: 12/12/2022]
Abstract
Aldosterone and the mineralocorticoid receptor (MR) are key elements for maintaining fluid and electrolyte homeostasis as well as regulation of blood pressure. Loss-of-function mutations of the MR are responsible for renal pseudohypoaldosteronism type 1 (PHA1), a rare disease of mineralocorticoid resistance presenting in the newborn with weight loss, failure to thrive, vomiting and dehydration, associated with hyperkalemia and metabolic acidosis, despite extremely elevated levels of plasma renin and aldosterone. In contrast, a MR gain-of-function mutation has been associated with a familial form of inherited mineralocorticoid hypertension exacerbated by pregnancy. In addition to rare variants, frequent functional single nucleotide polymorphisms of the MR are associated with salt sensitivity, blood pressure, stress response and depression in the general population. This review will summarize our knowledge on MR mutations in PHA1, reporting our experience on the genetic diagnosis in a large number of patients performed in the last 10 years at a national reference center for the disease. We will also discuss the influence of rare MR variants on blood pressure and salt sensitivity as well as on stress and cognitive functions in the general population.
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Affiliation(s)
- Maria-Christina Zennaro
- INSERMParis Cardiovascular Research Center, Paris, France
- Université Paris DescartesSorbonne Paris Cité, Paris, France
- Assistance Publique-Hôpitaux de ParisHôpital Européen Georges Pompidou, Service de Génétique, Paris, France
| | - Fabio Fernandes-Rosa
- INSERMParis Cardiovascular Research Center, Paris, France
- Université Paris DescartesSorbonne Paris Cité, Paris, France
- Assistance Publique-Hôpitaux de ParisHôpital Européen Georges Pompidou, Service de Génétique, Paris, France
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45
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Willam A, Aufy M, Tzotzos S, El-Malazi D, Poser F, Wagner A, Unterköfler B, Gurmani D, Martan D, Iqbal SM, Fischer B, Fischer H, Pietschmann H, Czikora I, Lucas R, Lemmens-Gruber R, Shabbir W. TNF Lectin-Like Domain Restores Epithelial Sodium Channel Function in Frameshift Mutants Associated with Pseudohypoaldosteronism Type 1B. Front Immunol 2017; 8:601. [PMID: 28611771 PMCID: PMC5447021 DOI: 10.3389/fimmu.2017.00601] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Accepted: 05/08/2017] [Indexed: 11/28/2022] Open
Abstract
Previous in vitro studies have indicated that tumor necrosis factor (TNF) activates amiloride-sensitive epithelial sodium channel (ENaC) current through its lectin-like (TIP) domain, since cyclic peptides mimicking the TIP domain (e.g., solnatide), showed ENaC-activating properties. In the current study, the effects of TNF and solnatide on individual ENaC subunits or ENaC carrying mutated glycosylation sites in the α-ENaC subunit were compared, revealing a similar mode of action for TNF and solnatide and corroborating the previous assumption that the lectin-like domain of TNF is the relevant molecular structure for ENaC activation. Accordingly, TNF enhanced ENaC current by increasing open probability of the glycosylated channel, position N511 in the α-ENaC subunit being identified as the most important glycosylation site. TNF significantly increased Na+ current through ENaC comprising only the pore forming subunits α or δ, was less active in ENaC comprising only β-subunits, and showed no effect on ENaC comprising γ-subunits. TNF did not increase the membrane abundance of ENaC subunits to the extent observed with solnatide. Since the α-subunit is believed to play a prominent role in the ENaC current activating effect of TNF and TIP, we investigated whether TNF and solnatide can enhance αβγ-ENaC current in α-ENaC loss-of-function frameshift mutants. The efficacy of solnatide has been already proven in pathological conditions involving ENaC in phase II clinical trials. The frameshift mutations αI68fs, αT169fs, αP197fs, αE272fs, αF435fs, αR438fs, αY447fs, αR448fs, αS452fs, and αT482fs have been reported to cause pseudohypoaldosteronism type 1B (PHA1B), a rare, life-threatening, salt-wasting disease, which hitherto has been treated only symptomatically. In a heterologous expression system, all frameshift mutants showed significantly reduced amiloride-sensitive whole-cell current compared to wild type αβγ-ENaC, whereas membrane abundance varied between mutants. Solnatide restored function in α-ENaC frameshift mutants to current density levels of wild type ENaC or higher despite their lacking a binding site for solnatide, previously located to the region between TM2 and the C-terminus of the α-subunit. TNF similarly restored current density to wild type levels in the mutant αR448fs. Activation of βγ-ENaC may contribute to this moderate current enhancement, but whatever the mechanism, experimental data indicate that solnatide could be a new strategy to treat PHA1B.
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Affiliation(s)
- Anita Willam
- Department of Pharmacology and Toxicology, University of Vienna, Vienna, Austria.,APEPTICO GmbH, Vienna, Austria
| | - Mohammed Aufy
- Department of Pharmacology and Toxicology, University of Vienna, Vienna, Austria
| | | | - Dina El-Malazi
- Department of Pharmacology and Toxicology, University of Vienna, Vienna, Austria
| | - Franziska Poser
- Department of Pharmacology and Toxicology, University of Vienna, Vienna, Austria
| | - Alina Wagner
- Department of Pharmacology and Toxicology, University of Vienna, Vienna, Austria
| | - Birgit Unterköfler
- Department of Pharmacology and Toxicology, University of Vienna, Vienna, Austria
| | - Didja Gurmani
- Department of Pharmacology and Toxicology, University of Vienna, Vienna, Austria
| | - David Martan
- Department of Pharmacology and Toxicology, University of Vienna, Vienna, Austria
| | | | | | | | | | - Istvan Czikora
- Vascular Biology Center, Medical College of Georgia, Augusta University, Augusta, GA, United States
| | - Rudolf Lucas
- Vascular Biology Center, Medical College of Georgia, Augusta University, Augusta, GA, United States
| | - Rosa Lemmens-Gruber
- Department of Pharmacology and Toxicology, University of Vienna, Vienna, Austria
| | - Waheed Shabbir
- Department of Pharmacology and Toxicology, University of Vienna, Vienna, Austria.,APEPTICO GmbH, Vienna, Austria
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46
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Casas-Alba D, Vila Cots J, Monfort Carretero L, Martorell Sampol L, Zennaro MC, Jeunemaitre X, Camacho Díaz JA. Pseudohypoaldosteronism types I and II: little more than a name in common. J Pediatr Endocrinol Metab 2017; 30:597-601. [PMID: 28593901 DOI: 10.1515/jpem-2016-0467] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Accepted: 03/06/2017] [Indexed: 11/15/2022]
Abstract
Pseudohypoaldosteronism (PHA) comprises a diverse group of rare diseases characterized by sodium and potassium imbalances incorrectly attributed to a defect in aldosterone production. Two different forms of PHA have been described, type I (PHAI) and type II (PHAII). PHAI has been subclassified into renal and systemic. Given the rarity and heterogeneity of this group of disorders we report three patients who carry PHA and a brief revision of current literature focused on the comparative analysis of PHAI and PHAII. Cases 1 and 2 presented with hyponatremia, hyperkalemia, metabolic acidosis and elevated plasma aldosterone and plasma renin activity in the neonatal period. Sequence analysis of the NRC2 gene demonstrated a novel heterozygous c.403C>T mutation in case 1 and a complete deletion in case 2, confirming the diagnosis of renal PHAI. Case 3 was a 4-year-old with hypertension, hyperkalemia, metabolic acidosis, normal plasma aldosterone and decreased plasma renin activity. Sequence analysis of the CUL3 gene demonstrated a previously unreported heterozygous c.1377+2T>3 mutation, confirming the diagnosis of PHAII-E. We highlight the importance of the determination of plasma aldosterone and plasma renin activity in the context of persistent sodium and potassium imbalances in children.
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Affiliation(s)
- Dídac Casas-Alba
- Pediatrics Department, Hospital Sant Joan de Déu (University of Barcelona), Barcelona
| | - Jordi Vila Cots
- Nephrology Department, Hospital Sant Joan de Déu (University of Barcelona), Barcelona
| | | | - Loreto Martorell Sampol
- Molecular Genetics Department, Hospital Sant Joan de Déu (University of Barcelona), Barcelona
| | - Maria-Christina Zennaro
- Assistance Publique-Hôpitaux de Paris, Hôpital Européen Georges Pompidou, Service de Génétique, Paris
| | - Xavier Jeunemaitre
- Assistance Publique-Hôpitaux de Paris, Hôpital Européen Georges Pompidou, Service de Génétique, Paris
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47
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Systemic Pseudohypoaldosteronism Type I: A Case Report and Review of the Literature. Case Rep Pediatr 2017; 2017:7939854. [PMID: 28484659 PMCID: PMC5412170 DOI: 10.1155/2017/7939854] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Revised: 02/15/2017] [Accepted: 03/19/2017] [Indexed: 12/12/2022] Open
Abstract
Systemic pseudohypoaldosteronism (PHA) type I is a rare genetic disorder resulting from mutations in the subunits of the epithelial sodium channel that manifests as severe salt wasting, hyperkalemia, and metabolic acidosis in infancy. In this article we report a patient with systemic PHA type I presenting with severe dehydration due to salt wasting at 6 days of life. She was found to have a known mutation in the SCNN1A gene and subsequently required treatment with sodium supplementation. We also review the clinical presentation, differential diagnosis, and treatment of systemic PHA type I and summarize data from 27 cases with follow-up data.
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48
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Bizzarri C, Pedicelli S, Cappa M, Cianfarani S. Water Balance and 'Salt Wasting' in the First Year of Life: The Role of Aldosterone-Signaling Defects. Horm Res Paediatr 2017; 86:143-153. [PMID: 27598420 DOI: 10.1159/000449057] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Accepted: 08/10/2016] [Indexed: 11/19/2022] Open
Abstract
In newborns and infants, dehydration and salt wasting represent a relatively common cause of admission to hospital and may result in life-threatening complications. Kidneys are responsible for electrolyte homoeostasis, but neonatal kidneys show low glomerular filtration rate and immaturity of the distal nephron, leading to reduced ability to concentrate urine. High extrarenal fluid losses often contribute to the increased occurrence of electrolyte disorders. Aldosterone is essential for sodium retention in the kidney, salivary glands, sweat glands and colon. A partial and transient aldosterone resistance is present in newborns and infants, thus reducing the capability of maintaining sodium balance in specific pathological conditions. The present review examines the mechanisms making infants more susceptible to salt wasting. Peculiar aspects of renal physiology in the first year of life and management of electrolyte disorders (i.e. sodium and potassium) are considered. Finally, inherited disorders associated with neonatal salt wasting are examined in detail. © 2016 S. Karger AG, Basel.
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Affiliation(s)
- Carla Bizzarri
- Unit of Endocrinology and Diabetes, 'Bambino Gesù' Children's Hospital, Rome, Italy
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49
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Bustamante-Marin XM, Ostrowski LE. Cilia and Mucociliary Clearance. Cold Spring Harb Perspect Biol 2017; 9:cshperspect.a028241. [PMID: 27864314 DOI: 10.1101/cshperspect.a028241] [Citation(s) in RCA: 356] [Impact Index Per Article: 50.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Mucociliary clearance (MCC) is the primary innate defense mechanism of the lung. The functional components are the protective mucous layer, the airway surface liquid layer, and the cilia on the surface of ciliated cells. The cilia are specialized organelles that beat in metachronal waves to propel pathogens and inhaled particles trapped in the mucous layer out of the airways. In health this clearance mechanism is effective, but in patients with primary cilia dyskinesia (PCD) the cilia are abnormal, resulting in deficient MCC and chronic lung disease. This demonstrates the critical importance of the cilia for human health. In this review, we summarize the current knowledge of the components of the MCC apparatus, focusing on the role of cilia in MCC.
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Affiliation(s)
- Ximena M Bustamante-Marin
- Marsico Lung Institute, Cystic Fibrosis and Pulmonary Diseases Research and Treatment Center, University of North Carolina, Chapel Hill, North Carolina 27599
| | - Lawrence E Ostrowski
- Marsico Lung Institute, Cystic Fibrosis and Pulmonary Diseases Research and Treatment Center, University of North Carolina, Chapel Hill, North Carolina 27599
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50
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Willam A, Aufy M, Tzotzos S, Evanzin H, Chytracek S, Geppert S, Fischer B, Fischer H, Pietschmann H, Czikora I, Lucas R, Lemmens-Gruber R, Shabbir W. Restoration of Epithelial Sodium Channel Function by Synthetic Peptides in Pseudohypoaldosteronism Type 1B Mutants. Front Pharmacol 2017; 8:85. [PMID: 28286482 PMCID: PMC5323398 DOI: 10.3389/fphar.2017.00085] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Accepted: 02/09/2017] [Indexed: 12/20/2022] Open
Abstract
The synthetically produced cyclic peptides solnatide (a.k.a. TIP or AP301) and its congener AP318, whose molecular structures mimic the lectin-like domain of human tumor necrosis factor (TNF), have been shown to activate the epithelial sodium channel (ENaC) in various cell- and animal-based studies. Loss-of-ENaC-function leads to a rare, life-threatening, salt-wasting syndrome, pseudohypoaldosteronism type 1B (PHA1B), which presents with failure to thrive, dehydration, low blood pressure, anorexia and vomiting; hyperkalemia, hyponatremia and metabolic acidosis suggest hypoaldosteronism, but plasma aldosterone and renin activity are high. The aim of the present study was to investigate whether the ENaC-activating effect of solnatide and AP318 could rescue loss-of-function phenotype of ENaC carrying mutations at conserved amino acid positions observed to cause PHA1B. The macroscopic Na+ current of all investigated mutants was decreased compared to wild type ENaC when measured in whole-cell patch clamp experiments, and a great variation in the membrane abundance of different mutant ENaCs was observed with Western blotting experiments. However, whatever mechanism leads to loss-of-function of the studied ENaC mutations, the synthetic peptides solnatide and AP318 could restore ENaC function up to or even higher than current levels of wild type ENaC. As therapy of PHA1B is only symptomatic so far, the peptides solnatide and AP318, which directly target ENaC, are promising candidates for the treatment of the channelopathy-caused disease PHA1B.
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Affiliation(s)
- Anita Willam
- Department of Pharmacology and Toxicology, University of Vienna Vienna, Austria
| | - Mohammed Aufy
- Department of Pharmacology and Toxicology, University of Vienna Vienna, Austria
| | | | - Heinrich Evanzin
- Department of Pharmacology and Toxicology, University of Vienna Vienna, Austria
| | - Sabine Chytracek
- Department of Pharmacology and Toxicology, University of Vienna Vienna, Austria
| | - Sabrina Geppert
- Department of Pharmacology and Toxicology, University of Vienna Vienna, Austria
| | | | | | | | - Istvan Czikora
- Vascular Biology Center, Medical College of Georgia, Augusta University Augusta, GA, USA
| | - Rudolf Lucas
- Vascular Biology Center, Medical College of Georgia, Augusta University Augusta, GA, USA
| | - Rosa Lemmens-Gruber
- Department of Pharmacology and Toxicology, University of Vienna Vienna, Austria
| | - Waheed Shabbir
- Department of Pharmacology and Toxicology, University of ViennaVienna, Austria; APEPTICO GmbHVienna, Austria
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