1
|
Chen Y, Yu X, Yan Z, Zhang S, Zhang J, Guo W. Role of epithelial sodium channel-related inflammation in human diseases. Front Immunol 2023; 14:1178410. [PMID: 37559717 PMCID: PMC10407551 DOI: 10.3389/fimmu.2023.1178410] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Accepted: 06/29/2023] [Indexed: 08/11/2023] Open
Abstract
The epithelial sodium channel (ENaC) is a heterotrimer and is widely distributed throughout the kidneys, blood vessels, lungs, colons, and many other organs. The basic role of the ENaC is to mediate the entry of Na+ into cells; the ENaC also has an important regulatory function in blood pressure, airway surface liquid (ASL), and endothelial cell function. Aldosterone, serum/glucocorticoid kinase 1 (SGK1), shear stress, and posttranslational modifications can regulate the activity of the ENaC; some ion channels also interact with the ENaC. In recent years, it has been found that the ENaC can lead to immune cell activation, endothelial cell dysfunction, aggravated inflammation involved in high salt-induced hypertension, cystic fibrosis, pseudohypoaldosteronism (PHA), and tumors; some inflammatory cytokines have been reported to have a regulatory role on the ENaC. The ENaC hyperfunction mediates the increase of intracellular Na+, and the elevated exchange of Na+ with Ca2+ leads to an intracellular calcium overload, which is an important mechanism for ENaC-related inflammation. Some of the research on the ENaC is controversial or unclear; we therefore reviewed the progress of studies on the role of ENaC-related inflammation in human diseases and their mechanisms.
Collapse
Affiliation(s)
- Yabin Chen
- Department of Hepatobiliary and Pancreatic Surgery, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
- National Organ Transplantation (Liver &Kidney Transplantation) Physician Training Centre, Zhengzhou, China
- National Regional Medical Treatment Centre of Henan Organ Transplantation, Zhengzhou, China
| | - Xiao Yu
- Department of Hepatobiliary and Pancreatic Surgery, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
- National Organ Transplantation (Liver &Kidney Transplantation) Physician Training Centre, Zhengzhou, China
- National Regional Medical Treatment Centre of Henan Organ Transplantation, Zhengzhou, China
| | - Zhiping Yan
- Henan Organ Transplantation Centre, Zhengzhou, China
- Henan Engineering and Research Center for Diagnosis and Treatment of Hepatobiliary and Pancreatic Surgical Diseases, Zhengzhou, China
| | - Shuijun Zhang
- Henan Research Centre for Organ Transplantation, Zhengzhou, China
| | - Jiacheng Zhang
- Henan Key Laboratory for Digestive Organ Transplantation, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Wenzhi Guo
- Department of Hepatobiliary and Pancreatic Surgery, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
- Open and Key Laboratory for Hepatobiliary and Pancreatic Surgery and Digestive Organ Transplantation at Henan Universities, Zhengzhou, China
| |
Collapse
|
2
|
Lawong RY, May F, Etang EC, Vorrat P, George J, Weder J, Kockler D, Preller M, Althaus M. Recording Sodium Self-Inhibition of Epithelial Sodium Channels Using Automated Electrophysiology in Xenopus Oocytes. MEMBRANES 2023; 13:membranes13050529. [PMID: 37233590 DOI: 10.3390/membranes13050529] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Revised: 05/13/2023] [Accepted: 05/17/2023] [Indexed: 05/27/2023]
Abstract
The epithelial sodium channel (ENaC) is a key regulator of sodium homeostasis that contributes to blood pressure control. ENaC open probability is adjusted by extracellular sodium ions, a mechanism referred to as sodium self-inhibition (SSI). With a growing number of identified ENaC gene variants associated with hypertension, there is an increasing demand for medium- to high-throughput assays allowing the detection of alterations in ENaC activity and SSI. We evaluated a commercially available automated two-electrode voltage-clamp (TEVC) system that records transmembrane currents of ENaC-expressing Xenopus oocytes in 96-well microtiter plates. We employed guinea pig, human and Xenopus laevis ENaC orthologs that display specific magnitudes of SSI. While demonstrating some limitations over traditional TEVC systems with customized perfusion chambers, the automated TEVC system was able to detect the established SSI characteristics of the employed ENaC orthologs. We were able to confirm a reduced SSI in a gene variant, leading to C479R substitution in the human α-ENaC subunit that has been reported in Liddle syndrome. In conclusion, automated TEVC in Xenopus oocytes can detect SSI of ENaC orthologs and variants associated with hypertension. For precise mechanistic and kinetic analyses of SSI, optimization for faster solution exchange rates is recommended.
Collapse
Affiliation(s)
- Rene Y Lawong
- Department of Natural Sciences, Institute for Functional Gene Analytics, Bonn-Rhein-Sieg University of Applied Sciences, 53359 Rheinbach, Germany
| | - Fabian May
- Department of Natural Sciences, Institute for Functional Gene Analytics, Bonn-Rhein-Sieg University of Applied Sciences, 53359 Rheinbach, Germany
| | - Etang C Etang
- Department of Natural Sciences, Institute for Functional Gene Analytics, Bonn-Rhein-Sieg University of Applied Sciences, 53359 Rheinbach, Germany
| | - Philipp Vorrat
- Department of Natural Sciences, Institute for Functional Gene Analytics, Bonn-Rhein-Sieg University of Applied Sciences, 53359 Rheinbach, Germany
| | - Jonas George
- Department of Natural Sciences, Institute for Functional Gene Analytics, Bonn-Rhein-Sieg University of Applied Sciences, 53359 Rheinbach, Germany
| | - Julia Weder
- Department of Natural Sciences, Institute for Functional Gene Analytics, Bonn-Rhein-Sieg University of Applied Sciences, 53359 Rheinbach, Germany
| | - Dagmar Kockler
- Department of Natural Sciences, Institute for Functional Gene Analytics, Bonn-Rhein-Sieg University of Applied Sciences, 53359 Rheinbach, Germany
| | - Matthias Preller
- Department of Natural Sciences, Institute for Functional Gene Analytics, Bonn-Rhein-Sieg University of Applied Sciences, 53359 Rheinbach, Germany
| | - Mike Althaus
- Department of Natural Sciences, Institute for Functional Gene Analytics, Bonn-Rhein-Sieg University of Applied Sciences, 53359 Rheinbach, Germany
| |
Collapse
|
3
|
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: 7] [Impact Index Per Article: 7.0] [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.
Collapse
Affiliation(s)
- Rosa Lemmens-Gruber
- Department of Pharmaceutical Sciences, Division of Pharmacology and Toxicology, University of Vienna, A-1090 Vienna, Austria
| | | |
Collapse
|
4
|
Ahmad T, Ertuglu LA, Masenga SK, Kleyman TR, Kirabo A. The epithelial sodium channel in inflammation and blood pressure modulation. Front Cardiovasc Med 2023; 10:1130148. [PMID: 37123470 PMCID: PMC10132033 DOI: 10.3389/fcvm.2023.1130148] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Accepted: 03/24/2023] [Indexed: 05/02/2023] Open
Abstract
A major regulator of blood pressure and volume homeostasis in the kidney is the epithelial sodium channel (ENaC). ENaC is composed of alpha(α)/beta(β)/gamma(γ) or delta(δ)/beta(β)/gamma(γ) subunits. The δ subunit is functional in the guinea pig, but not in routinely used experimental rodent models including rat or mouse, and thus remains the least understood of the four subunits. While the δ subunit is poorly expressed in the human kidney, we recently found that its gene variants are associated with blood pressure and kidney function. The δ subunit is expressed in the human vasculature where it may influence vascular function. Moreover, we recently found that the δ subunit is also expressed human antigen presenting cells (APCs). Our studies indicate that extracellular Na+ enters APCs via ENaC leading to inflammation and salt-induced hypertension. In this review, we highlight recent findings on the role of extra-renal ENaC in inflammation, vascular dysfunction, and blood pressure modulation. Targeting extra-renal ENaC may provide new drug therapies for salt-induced hypertension.
Collapse
Affiliation(s)
- Taseer Ahmad
- Department of Pharmacology, College of Pharmacy, University of Sargodha, Sargodha, Pakistan
- Division of Clinical Pharmacology, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, United States
| | - Lale A. Ertuglu
- Division of Nephrology, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, United States
| | - Sepiso K. Masenga
- Department of Physiological Sciences, School of Medicine and Health Sciences, Mulungushi University, Livingstone, Zambia
| | - Thomas R. Kleyman
- Department of Medicine, University of Pittsburgh, Pittsburgh, PA, United States
- Department of Cell Biology, University of Pittsburgh, Pittsburgh, PA, United States
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA, United States
| | - Annet Kirabo
- Division of Clinical Pharmacology, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, United States
| |
Collapse
|
5
|
Maxeiner S, Krasteva-Christ G, Althaus M. Pitfalls of using sequence databases for heterologous expression studies - a technical review. J Physiol 2023; 601:1611-1623. [PMID: 36762618 DOI: 10.1113/jp284066] [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: 12/07/2022] [Accepted: 02/07/2023] [Indexed: 02/11/2023] Open
Abstract
Synthesis of DNA fragments based on gene sequences that are available in public resources has become an efficient and affordable method that has gradually replaced traditional cloning efforts such as PCR cloning from cDNA. However, database entries based on genome sequencing results are prone to errors which can lead to false sequence information and, ultimately, errors in functional characterisation of proteins such as ion channels and transporters in heterologous expression systems. We have identified five common problems that repeatedly appear in public resources: (1) Not every gene has yet been annotated; (2) not all gene annotations are necessarily correct; (3) transcripts may contain automated corrections; (4) there are mismatches between gene, mRNA and protein sequences; and (5) splicing patterns often lack experimental validation. This technical review highlights and provides a strategy to bypass these issues in order to avoid critical mistakes that could impact future studies of any gene/protein of interest in heterologous expression systems.
Collapse
Affiliation(s)
- Stephan Maxeiner
- Institute for Anatomy and Cell Biology, Saarland University, Homburg, Germany
| | | | - Mike Althaus
- Department of Natural Sciences, Institute for Functional Gene Analytics, Bonn-Rhein-Sieg University of Applied Sciences, Rheinbach, Germany
| |
Collapse
|
6
|
Lin J, Gettings SM, Talbi K, Schreiber R, Taggart MJ, Preller M, Kunzelmann K, Althaus M, Gray MA. Pharmacological inhibitors of the cystic fibrosis transmembrane conductance regulator exert off-target effects on epithelial cation channels. Pflugers Arch 2023; 475:167-179. [PMID: 36205782 PMCID: PMC9849171 DOI: 10.1007/s00424-022-02758-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Revised: 09/28/2022] [Accepted: 10/03/2022] [Indexed: 02/01/2023]
Abstract
The cystic fibrosis transmembrane conductance regulator (CFTR) anion channel and the epithelial Na+ channel (ENaC) play essential roles in transepithelial ion and fluid transport in numerous epithelial tissues. Inhibitors of both channels have been important tools for defining their physiological role in vitro. However, two commonly used CFTR inhibitors, CFTRinh-172 and GlyH-101, also inhibit non-CFTR anion channels, indicating they are not CFTR specific. However, the potential off-target effects of these inhibitors on epithelial cation channels has to date not been addressed. Here, we show that both CFTR blockers, at concentrations routinely employed by many researchers, caused a significant inhibition of store-operated calcium entry (SOCE) that was time-dependent, poorly reversible and independent of CFTR. Patch clamp experiments showed that both CFTRinh-172 and GlyH-101 caused a significant block of Orai1-mediated whole cell currents, establishing that they likely reduce SOCE via modulation of this Ca2+ release-activated Ca2+ (CRAC) channel. In addition to off-target effects on calcium channels, both inhibitors significantly reduced human αβγ-ENaC-mediated currents after heterologous expression in Xenopus oocytes, but had differential effects on δβγ-ENaC function. Molecular docking identified two putative binding sites in the extracellular domain of ENaC for both CFTR blockers. Together, our results indicate that caution is needed when using these two CFTR inhibitors to dissect the role of CFTR, and potentially ENaC, in physiological processes.
Collapse
Affiliation(s)
- JinHeng Lin
- grid.1006.70000 0001 0462 7212Biosciences Institute, Newcastle University, Newcastle upon Tyne, NE2 4HH UK ,grid.4991.50000 0004 1936 8948Present Address: Department of Pharmacology, University of Oxford, Oxford, OX1 3QT UK
| | - Sean M. Gettings
- grid.1006.70000 0001 0462 7212School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, NE1 7RU UK
| | - Khaoula Talbi
- grid.7727.50000 0001 2190 5763Physiological Institute, University of Regensburg, 93053 Regensburg, Germany
| | - Rainer Schreiber
- grid.7727.50000 0001 2190 5763Physiological Institute, University of Regensburg, 93053 Regensburg, Germany
| | - Michael J. Taggart
- grid.1006.70000 0001 0462 7212Biosciences Institute, Newcastle University, Newcastle upon Tyne, NE2 4HH UK
| | - Matthias Preller
- grid.425058.e0000 0004 0473 3519Department of Natural Sciences/Institute for Functional Gene Analytics, Structural Biology Group, Bonn-Rhein-Sieg University of Applied Sciences, 53359 Rheinbach, Germany
| | - Karl Kunzelmann
- grid.7727.50000 0001 2190 5763Physiological Institute, University of Regensburg, 93053 Regensburg, Germany
| | - Mike Althaus
- grid.1006.70000 0001 0462 7212School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, NE1 7RU UK ,grid.425058.e0000 0004 0473 3519Present Address: Department of Natural Sciences /Institute for Functional Gene Analytics, Ion Transport Physiology Group, Bonn-Rhein-Sieg University of Applied Sciences, 53359 Rheinbach, Germany
| | - Michael A. Gray
- grid.1006.70000 0001 0462 7212Biosciences Institute, Newcastle University, Newcastle upon Tyne, NE2 4HH UK
| |
Collapse
|
7
|
Ye Z, Xia Y, Li L, Li B, Chen W, Han S, Zhou X, Chen L, Yu W, Ruan Y, Cheng F. Effect of transmembrane protein 100 on prostate cancer progression by regulating SCNN1D through the FAK/PI3K/AKT pathway. Transl Oncol 2022; 27:101578. [PMID: 36375375 PMCID: PMC9661392 DOI: 10.1016/j.tranon.2022.101578] [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] [Received: 08/16/2022] [Revised: 10/04/2022] [Accepted: 10/24/2022] [Indexed: 11/13/2022] Open
Abstract
The effects of transmembrane (TMEM) proteins in the progression of prostate cancer (PCa) remain unknown. This study aims to explore the functions of TMEM100 in PCa. To explore the expression, regulation, and effects of TMEM100 in PCa, two PCa cell lines and 30 PCa tissue samples with adjacent control tissues were examined. Online databases, immunohistochemistry, immunofluorescence, western blot, flow cytometry, colony formation, wound healing, transwell assays, and xenograft mouse models were used to explore effects of TMEM100 relevant to PCa. TMEM100 expression was shown to decrease in PCa patients, and low TMEM100 expression was associated with tumor stage and metastasis. Overexpression of TMEM100 suppressed PCa progression by inhibiting the FAK/PI3K/AKT signaling pathway. Tumor size was smaller in TMEM100 overexpressing PCa cells in xenograft mice than in control mice. We also found that TMEM100 could regulate SCNN1D by inhibiting FAK/PI3K/AKT signaling in PCa cell lines. Taken together, our findings indicate that TMEM100 is a tumor suppressor that plays a vital role in preventing PCa proliferation, migration, and invasion through inhibition of FAK/PI3K/AKT signaling. These studies suggest that TMEM100 can be used as a predictive biomarker and therapeutic target.
Collapse
Affiliation(s)
- Zehua Ye
- Corresponding author at: Department of Urology, Renmin hospital of Wuhan university, 238 Jiefang Road, Wuhan 430060, China.
| | - Yuqi Xia
- Corresponding author at: Department of Urology, Renmin hospital of Wuhan university, 238 Jiefang Road, Wuhan 430060, China.
| | - Lei Li
- Corresponding author at: Department of Urology, Renmin hospital of Wuhan university, 238 Jiefang Road, Wuhan 430060, China.
| | | | | | | | | | | | | | - Yuan Ruan
- Corresponding author at: Department of Urology, Renmin hospital of Wuhan university, 238 Jiefang Road, Wuhan 430060, China.
| | - Fan Cheng
- Corresponding author at: Department of Urology, Renmin hospital of Wuhan university, 238 Jiefang Road, Wuhan 430060, China.
| |
Collapse
|
8
|
Fronius M. Epithelial Na+ channel and the glycocalyx: a sweet and salty relationship for arterial shear stress sensing. Curr Opin Nephrol Hypertens 2022; 31:142-150. [PMID: 34966089 DOI: 10.1097/mnh.0000000000000779] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE OF REVIEW The ability of endothelial cells to sense mechanical force, and shear stress in particular, is crucial for normal vascular function. This relies on an intact endothelial glycocalyx that facilitates the production of nitric oxide (NO). An emerging arterial shear stress sensor is the epithelial Na+ channel (ENaC). This review highlights existing and new evidence for the interdependent activity of the glycocalyx and ENaC and its implications for vascular function. RECENT FINDINGS New evidence suggests that the glycocalyx and ENaC are physically connected and that this is important for shear stress sensing. The connection relies on N-glycans attached to glycosylated asparagines of α-ENaC. Removal of specific N-glycans reduced ENaC's shear stress response. Similar effects were observed following degradation of the glycocalyx. Endothelial specific viral transduction of α-ENaC increased blood pressure (∼40 mmHg). This increase was attenuated in animals transduced with an α-ENaC version lacking N-glycans. SUMMARY These observations indicate that ENaC is connected to the glycocalyx and their activity is interdependent to facilitate arterial shear stress sensation. Future research focusing on how N-glycans mediate this interaction can provide new insights for the understanding of vascular function in health and disease.
Collapse
Affiliation(s)
- Martin Fronius
- Department of Physiology, School of Biomedical Sciences
- HeartOtago, University of Otago, Dunedin
- Healthy Hearts Aotearoa New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, Centre of Research Excellence, Auckland, New Zealand
| |
Collapse
|