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Reutersberg B, Pelisek J, Ouda A, de Rougemont O, Rössler F, Zimmermann A. Baroreceptors in the Aortic Arch and Their Potential Role in Aortic Dissection and Aneurysms. J Clin Med 2022; 11:jcm11051161. [PMID: 35268252 PMCID: PMC8911340 DOI: 10.3390/jcm11051161] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Revised: 02/10/2022] [Accepted: 02/19/2022] [Indexed: 11/16/2022] Open
Abstract
The arterial baroreflex is a key autonomic regulator of blood pressure whose dysfunction has been related to several cardiovascular diseases. Changes in blood pressure are sensed by specific mechanosensory proteins, called baroreceptors, particularly located in the outer layer of the carotid sinus and the inner curvature of the aortic arch. The signal is propagated along the afferent nerves to the central nervous system and serves as negative feedback of the heart rate. Despite extensive research, the precise molecular nature of baroreceptors remains elusive. Current knowledge assumes that baroreceptors are ion channels at the nerve endings within the outer layer of the arteries. However, the evidence is based mainly on animal experiments, and the specific types of mechanosensitive receptors responsible for the signal transduction are still unknown. Only a few studies have investigated mechanosensory transmission in the aortic arch. In addition, although aortic dissection, and particularly type A involving the aortic arch, is one of the most life-threatening cardiovascular disorders, there is no knowledge about the impact of aortic dissection on baroreceptor function. In this review, we aim not to highlight the regulation of the heart rate but what mechanical stimuli and what possible ion channels transfer the corresponding signal within the aortic arch, summarizing and updating the current knowledge about baroreceptors, specifically in the aortic arch, and the impact of aortic pathologies on their function.
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Affiliation(s)
- Benedikt Reutersberg
- Department of Vascular Surgery, University Hospital Zurich, 8091 Zurich, Switzerland; (J.P.); (A.Z.)
- Correspondence: ; Tel.: +41-44-255-20-39
| | - Jaroslav Pelisek
- Department of Vascular Surgery, University Hospital Zurich, 8091 Zurich, Switzerland; (J.P.); (A.Z.)
| | - Ahmed Ouda
- Department of Cardiac Surgery, University Hospital Zurich, 8091 Zurich, Switzerland;
| | - Olivier de Rougemont
- Department of Surgery and Transplantation, University Hospital Zurich, 8091 Zurich, Switzerland; (O.d.R.); (F.R.)
| | - Fabian Rössler
- Department of Surgery and Transplantation, University Hospital Zurich, 8091 Zurich, Switzerland; (O.d.R.); (F.R.)
| | - Alexander Zimmermann
- Department of Vascular Surgery, University Hospital Zurich, 8091 Zurich, Switzerland; (J.P.); (A.Z.)
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Hartati YW, Komala DR, Hendrati D, Gaffar S, Hardianto A, Sofiatin Y, Bahti HH. An aptasensor using ceria electrodeposited-screen-printed carbon electrode for detection of epithelial sodium channel protein as a hypertension biomarker. ROYAL SOCIETY OPEN SCIENCE 2021; 8:202040. [PMID: 33972878 PMCID: PMC8074578 DOI: 10.1098/rsos.202040] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Accepted: 01/20/2021] [Indexed: 06/02/2023]
Abstract
Epithelial sodium channel (ENaC) is a transmembrane protein that has an essential role in maintaining the levels of sodium in blood plasma. A person with a family history of hypertension has a high enough amount of ENaC protein in the kidneys or other organs, so that the ENaC protein acts as a marker that a person is susceptible to hypertension. An aptasensor involves aptamers, which are oligonucleotides that function similar to antibodies, as sensing elements. An electrochemical aptasensor for the detection of ENaC was developed using a screen-printed carbon electrode (SPCE) which was modified by electrodeposition of cerium oxide (CeO2). The aptamer immobilization was via the streptavidin-biotin system. The measurement of changes in current of the active redox [Fe(CN)6]3-/4- was carried out by differential pulse voltammetry. The surfaces of SPCE and SPCE/CeO2 were characterized using scanning electron microscopy, voltammetry and electrochemical impedance spectroscopy. The Box-Behnken experimental optimization design revealed the streptavidin incubation time, aptamer incubation time and streptavidin concentrations were 30 min, 30 min and 10.8 µg ml-1, respectively. Various concentrations of ENaC were used to obtain the linearity range of 0.05-3.0 ng ml-1, and the limits of detection and quantification were 0.012 ng ml-1 and 0.038 ng ml-1, respectively. This aptasensor method has the potential to measure the ENaC protein levels in urine samples as well as to be a point-of-care device.
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Affiliation(s)
- Yeni Wahyuni Hartati
- Department of Chemistry, Faculty of Mathematics and Natural Sciences, Universitas Padjadjaran, Bandung, Indonesia
| | - Dina Ratna Komala
- Department of Chemistry, Faculty of Mathematics and Natural Sciences, Universitas Padjadjaran, Bandung, Indonesia
| | - Diana Hendrati
- Department of Chemistry, Faculty of Mathematics and Natural Sciences, Universitas Padjadjaran, Bandung, Indonesia
| | - Shabarni Gaffar
- Department of Chemistry, Faculty of Mathematics and Natural Sciences, Universitas Padjadjaran, Bandung, Indonesia
| | - Ari Hardianto
- Department of Chemistry, Faculty of Mathematics and Natural Sciences, Universitas Padjadjaran, Bandung, Indonesia
| | - Yulia Sofiatin
- Department of Public Health, Faculty of Medicine, Universitas Padjadjaran, Bandung, Indonesia
| | - Husein Hernandi Bahti
- Department of Chemistry, Faculty of Mathematics and Natural Sciences, Universitas Padjadjaran, Bandung, Indonesia
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Komala DR, Hardianto A, Gaffar S, Hartati YW. An Epithelial Sodium Channel (ENaC)-Specific Aptamer Determined through Structure-Based Virtual Screening for the Development of Hypertension Early Detection System. PHARMACEUTICAL SCIENCES 2020. [DOI: 10.34172/ps.2020.63] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Background: Epithelial sodium channel (ENaC) is a transmembrane protein involved in maintaining sodium levels in blood plasma. It is also a potential biomarker for the early detection of hypertension since the amount of ENaC is related to the familial history of hypertension. ENaC can be detected by an aptamer, a single-stranded DNA (ssDNA) or RNA which offers advantages over an antibody. This study aimed to obtain an ssDNA aptamer specific to ENaC through virtual screening. Methods: Forty-one aptamers were retrieved from the Protein Data Bank (PDB) and the RNA was converted to ssDNA aptamers. The X-ray crystallographic structure of ENaC protein was remodelled using Modeller 9.20 to resolve missing residues. Molecular docking of aptamers against ENaC was performed using Patchdock and Firedock, then the selected aptamer was subjected to molecular docking against other ion channel proteins to assess its selectivity to ENaC. A molecular dynamics (MD) simulation was also conducted using Amber16 to acquire an in-depth understanding of the interaction within the aptamer-ENaC complex. Results: The virtual screening suggested that the ssDNA of iSpinach aptamer (PDB: 5OB3) displayed the strongest binding to ENaC (-49.46 kcal/mol) and was selective for ENaC over the other ion protein channels. An MMGBSA calculation on the complex of aptamer-ENaC revealed binding energy of -42,12 kcal/mol. Conclusion: The iSpinach-based aptamer is a potential probe for detecting ENaC or iDE and may be useful for the development of hypertension early detection systems.
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Affiliation(s)
- Dina Ratna Komala
- Department of Chemistry, Faculty of Mathematics and Natural Sciences, Universitas Padjadjaran, Indonesia
| | - Ari Hardianto
- Department of Chemistry, Faculty of Mathematics and Natural Sciences, Universitas Padjadjaran, Indonesia
| | - Shabarni Gaffar
- Department of Chemistry, Faculty of Mathematics and Natural Sciences, Universitas Padjadjaran, Indonesia
| | - Yeni Wahyuni Hartati
- Department of Chemistry, Faculty of Mathematics and Natural Sciences, Universitas Padjadjaran, Indonesia
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Mechanical Strain-Mediated Tenogenic Differentiation of Mesenchymal Stromal Cells Is Regulated through Epithelial Sodium Channels. Stem Cells Int 2020; 2020:5385960. [PMID: 32908542 PMCID: PMC7450316 DOI: 10.1155/2020/5385960] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Revised: 06/18/2020] [Accepted: 07/11/2020] [Indexed: 11/17/2022] Open
Abstract
It has been suggested that mechanical strain may elicit cell differentiation in adult somatic cells through activation of epithelial sodium channels (ENaC). However, such phenomenon has not been previously demonstrated in mesenchymal stromal cells (MSCs). The present study was thus conducted to investigate the role of ENaC in human bone marrow-derived MSCs (hMSCs) tenogenic differentiation during uniaxial tensile loading. Passaged-2 hMSCs were seeded onto silicone chambers coated with collagen I and subjected to stretching at 1 Hz frequency and 8% strain for 6, 24, 48, and 72 hours. Analyses at these time points included cell morphology and alignment observation, immunocytochemistry and immunofluorescence staining (collagen I, collagen III, fibronectin, and N-cadherin), and gene expression (ENaC subunits, and tenogenic markers). Unstrained cells at similar time points served as the control group. To demonstrate the involvement of ENaC in the differentiation process, an ENaC blocker (benzamil) was used and the results were compared to the noninhibited hMSCs. ENaC subunits' (α, β, γ, and δ) expression was observed in hMSCs, although only α subunit was significantly increased during stretching. An increase in tenogenic genes' (collagen1, collagen3, decorin, tenascin-c, scleraxis, and tenomodulin) and proteins' (collagen I, collagen III, fibronectin, and N-cadherin) expression suggests that hMSCs underwent tenogenic differentiation when subjected to uniaxial loading. Inhibition of ENaC function resulted in decreased expression of these markers, thereby suggesting that ENaC plays a vital role in tenogenic differentiation of hMSCs during mechanical loading.
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Rao MC. Physiology of Electrolyte Transport in the Gut: Implications for Disease. Compr Physiol 2019; 9:947-1023. [PMID: 31187895 DOI: 10.1002/cphy.c180011] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
We now have an increased understanding of the genetics, cell biology, and physiology of electrolyte transport processes in the mammalian intestine, due to the availability of sophisticated methodologies ranging from genome wide association studies to CRISPR-CAS technology, stem cell-derived organoids, 3D microscopy, electron cryomicroscopy, single cell RNA sequencing, transgenic methodologies, and tools to manipulate cellular processes at a molecular level. This knowledge has simultaneously underscored the complexity of biological systems and the interdependence of multiple regulatory systems. In addition to the plethora of mammalian neurohumoral factors and their cross talk, advances in pyrosequencing and metagenomic analyses have highlighted the relevance of the microbiome to intestinal regulation. This article provides an overview of our current understanding of electrolyte transport processes in the small and large intestine, their regulation in health and how dysregulation at multiple levels can result in disease. Intestinal electrolyte transport is a balance of ion secretory and ion absorptive processes, all exquisitely dependent on the basolateral Na+ /K+ ATPase; when this balance goes awry, it can result in diarrhea or in constipation. The key transporters involved in secretion are the apical membrane Cl- channels and the basolateral Na+ -K+ -2Cl- cotransporter, NKCC1 and K+ channels. Absorption chiefly involves apical membrane Na+ /H+ exchangers and Cl- /HCO3 - exchangers in the small intestine and proximal colon and Na+ channels in the distal colon. Key examples of our current understanding of infectious, inflammatory, and genetic diarrheal diseases and of constipation are provided. © 2019 American Physiological Society. Compr Physiol 9:947-1023, 2019.
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Affiliation(s)
- Mrinalini C Rao
- Department of Physiology and Biophysics, University of Illinois at Chicago, Chicago, Illinois, USA
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Lithium Therapy Associated With Renal and Upper and Lower Urinary Tract Tumors: Results From a Retrospective Single-Center Analysis. J Clin Psychopharmacol 2019; 39:530-532. [PMID: 31425462 PMCID: PMC6727908 DOI: 10.1097/jcp.0000000000001098] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Tu H, Zhang D, Li YL. Cellular and Molecular Mechanisms Underlying Arterial Baroreceptor Remodeling in Cardiovascular Diseases and Diabetes. Neurosci Bull 2018; 35:98-112. [PMID: 30146675 DOI: 10.1007/s12264-018-0274-y] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Accepted: 05/31/2018] [Indexed: 01/23/2023] Open
Abstract
Clinical trials and animal experimental studies have demonstrated an association of arterial baroreflex impairment with the prognosis and mortality of cardiovascular diseases and diabetes. As a primary part of the arterial baroreflex arc, the pressure sensitivity of arterial baroreceptors is blunted and involved in arterial baroreflex dysfunction in cardiovascular diseases and diabetes. Changes in the arterial vascular walls, mechanosensitive ion channels, and voltage-gated ion channels contribute to the attenuation of arterial baroreceptor sensitivity. Some endogenous substances (such as angiotensin II and superoxide anion) can modulate these morphological and functional alterations through intracellular signaling pathways in impaired arterial baroreceptors. Arterial baroreceptors can be considered as a potential therapeutic target to improve the prognosis of patients with cardiovascular diseases and diabetes.
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Affiliation(s)
- Huiyin Tu
- Department of Emergency Medicine, University of Nebraska Medical Center, Omaha, NE, 68198, USA
| | - Dongze Zhang
- Department of Emergency Medicine, University of Nebraska Medical Center, Omaha, NE, 68198, USA
| | - Yu-Long Li
- Department of Emergency Medicine, University of Nebraska Medical Center, Omaha, NE, 68198, USA.
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Tamura S, Okada M, Kato S, Shinoda Y, Shioda N, Fukunaga K, Ui-Tei K, Ueda M. Ouabagenin is a naturally occurring LXR ligand without causing hepatic steatosis as a side effect. Sci Rep 2018; 8:2305. [PMID: 29396543 PMCID: PMC5797171 DOI: 10.1038/s41598-018-20663-z] [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: 09/04/2017] [Accepted: 01/23/2018] [Indexed: 12/23/2022] Open
Abstract
Ouabagenin (OBG) is an aglycone of the cardiotonic steroid ouabain and until now was considered a biologically inactive biosynthetic precursor. Herein, we revealed that OBG functions as a novel class of ligand for the liver X receptor (LXR). Luciferase reporter assays and in silico docking studies suggested that OBG has LXR-selective agonistic activity. In addition, OBG repressed the expression of epithelial sodium channel (ENaC), a LXR target gene, without causing hepatic steatosis, a typical side effect of conventional LXR ligands. This remarkable biological activity can be attributed to a unique mode of action; the LXR agonist activity mainly proceeds through the LXRβ subtype without affecting LXRα, unlike conventional LXR ligands. Thus, OBG is a novel class of LXR ligand that does not cause severe side effects, with potential for use as an antihypertensive diuretic or a tool compound for exploring LXR subtype-specific biological functions.
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Affiliation(s)
- Satoru Tamura
- Department of Chemistry, Graduate School of Science, Tohoku University, Sendai, Miyagi, 980-8578, Japan.,School of Pharmacy, Iwate Medical University, Shiwa-gun, Iwate, 028-3694, Japan
| | - Maiko Okada
- Institute of Medical Science, St. Marianna University Graduate School of Medicine, Kawasaki, Kanagawa, 970-8551, Japan.,Genome regulation and Molecular Pharmacogenomics, School of Bioscience and Biotechnology, Tokyo University of Technology, Hachioji, Tokyo, 192-0982, Japan
| | - Shigeaki Kato
- Iwaki Meisei University, Iwaki, Fukushima, 970-8551, Japan.,Research Institute of Innovative Medicine, Tokiwa Foundation, Iwaki, Fukushima, 972-8322, Japan
| | - Yasuharu Shinoda
- Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Miyagi, 980-8578, Japan
| | - Norifumi Shioda
- Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Miyagi, 980-8578, Japan
| | - Kohji Fukunaga
- Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Miyagi, 980-8578, Japan
| | - Kumiko Ui-Tei
- Graduate School of Science, The University of Tokyo, Tokyo, 113-0032, Japan
| | - Minoru Ueda
- Department of Chemistry, Graduate School of Science, Tohoku University, Sendai, Miyagi, 980-8578, Japan.
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Abstract
Objective: To review the recent developments in the mechanisms of epithelium sodium channels (ENaCs) induced bone formation and regulation. Data Sources: Studies written in English or Chinese were searched using Medline, PubMed and the index of Chinese-language literature with time restriction from 2005 to 2014. Keywords included ENaC, bone, bone formation, osteonecrosis, estrogen, and osteoporosis. Data from published articles about the structure of ENaC, mechanism of ENaC in bone formation in recent domestic and foreign literature were selected. Study Selection: Abstract and full text of all studies were required to obtain. Studies those were not accessible and those did not focus on the keywords were excluded. Results: ENaCs are tripolymer ion channels which are assembled from homologous α, β, and γ subunits. Crystal structure of ENaCs suggests that ENaC has a central ion-channel located in the central symmetry axis of the three subunits. ENaCs are protease sensitive channels whose iron-channel activity is regulated by the proteolytic reaction. Channel opening probability of ENaCs is regulated by proteinases, mechanical force, and shear stress. Several molecules are involved in regulation of ENaCs in bone formation, including nitride oxide synthases, voltage-sensitive calcium channels, and cyclooxygenase-2. Conclusion: The pathway of ENaC involved in shear stress has an effect on stimulating osteoblasts even bone formation by estrogen interference.
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Affiliation(s)
| | | | - Wei-Hua Xu
- Department of Orthopedics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430022, China
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Zhong Q, Liu C, Fan R, Duan S, Xu X, Zhao J, Mao S, Zhu W, Hao L, Yin F, Zhang L. Association of SCNN1B promoter methylation with essential hypertension. Mol Med Rep 2016; 14:5422-5428. [PMID: 27840946 DOI: 10.3892/mmr.2016.5905] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Accepted: 09/15/2016] [Indexed: 11/06/2022] Open
Abstract
The amiloride-sensitive sodium channel beta subunit (SCNN1B) gene encodes the beta subunit of the epithelial sodium channel, which is involved in blood pressure homeostasis. The aim of the present study was to investigate the association between SCNN1B gene promoter methylation and essential hypertension (EH), and to explore whether SCNN1B methylation was altered by antihypertensive therapy. The present study recruited 282 individuals: 94 controls, 94 incident cases and 94 prevalent cases. Subsequently, the methylation status of six CpG sites in the SCNN1B promoter region was measured using bisulfite pyrosequencing technology. Among the six CpG sites, a significant difference in CpG1 and CpG2 methylation levels were detected between controls and incident cases (CpG1: β‑standardized=0.17, adjusted P=0.015; CpG2: β‑standardized=‑0.41, adjusted P=0.001). In addition, a significant difference was detected in CpG1 methylation levels between incident cases and prevalent cases (β‑standardized=‑0.252, adjusted P=3.77E‑04). The present study also demonstrated that CpG1 and CpG2 methylation levels were significantly lower in males compared with in females (CpG1: t=‑3.180, P=0.002; CpG2: t=‑2.148, P=0.033). CpG1 methylation was also shown to be positively correlated with age (controls: r=0.285, P=0.008; incident cases: r=0.401, P=0.0001; prevalent cases: r=0.367, P=0.001). These results indicated a significant association between EH and SCNN1B methylation, which was affected by age, gender and antihypertensive therapy.
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Affiliation(s)
- Qilong Zhong
- Zhejiang Provincial Key Laboratory of Pathophysiology, School of Medicine, Ningbo University, Ningbo, Zhejiang 315211, P.R. China
| | - Chunyan Liu
- Clinical Laboratory, Ningbo Baizhang Street Community Health Service Center, Ningbo, Zhejiang 315200, P.R. China
| | - Rui Fan
- Zhejiang Provincial Key Laboratory of Pathophysiology, School of Medicine, Ningbo University, Ningbo, Zhejiang 315211, P.R. China
| | - Shiwei Duan
- Zhejiang Provincial Key Laboratory of Pathophysiology, School of Medicine, Ningbo University, Ningbo, Zhejiang 315211, P.R. China
| | - Xuting Xu
- Zhejiang Provincial Key Laboratory of Pathophysiology, School of Medicine, Ningbo University, Ningbo, Zhejiang 315211, P.R. China
| | - Jinshun Zhao
- Zhejiang Provincial Key Laboratory of Pathophysiology, School of Medicine, Ningbo University, Ningbo, Zhejiang 315211, P.R. China
| | - Shuqi Mao
- Zhejiang Provincial Key Laboratory of Pathophysiology, School of Medicine, Ningbo University, Ningbo, Zhejiang 315211, P.R. China
| | - Wen Zhu
- Zhejiang Provincial Key Laboratory of Pathophysiology, School of Medicine, Ningbo University, Ningbo, Zhejiang 315211, P.R. China
| | - Lingmei Hao
- Clinical laboratory, The Seventh Hospital of Ningbo, Ningbo, Zhejiang 315202, P.R. China
| | - Fengying Yin
- Clinical Laboratory, The First Hospital of Ningbo, Ningbo, Zhejiang 315010, P.R. China
| | - Lina Zhang
- Zhejiang Provincial Key Laboratory of Pathophysiology, School of Medicine, Ningbo University, Ningbo, Zhejiang 315211, P.R. China
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Nesterov V, Krueger B, Bertog M, Dahlmann A, Palmisano R, Korbmacher C. In Liddle Syndrome, Epithelial Sodium Channel Is Hyperactive Mainly in the Early Part of the Aldosterone-Sensitive Distal Nephron. Hypertension 2016; 67:1256-62. [DOI: 10.1161/hypertensionaha.115.07061] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Accepted: 03/16/2016] [Indexed: 11/16/2022]
Affiliation(s)
- Viatcheslav Nesterov
- From the Institut für Zelluläre und Molekulare Physiologie (V.N., B.K., M.B., C.K.), Universitätsklinikum Erlangen, Medizinische Klinik 4–Nephrologie und Hypertensiologie (A.D.), and Optical Imaging Center Erlangen (OICE) (R.P.), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Bettina Krueger
- From the Institut für Zelluläre und Molekulare Physiologie (V.N., B.K., M.B., C.K.), Universitätsklinikum Erlangen, Medizinische Klinik 4–Nephrologie und Hypertensiologie (A.D.), and Optical Imaging Center Erlangen (OICE) (R.P.), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Marko Bertog
- From the Institut für Zelluläre und Molekulare Physiologie (V.N., B.K., M.B., C.K.), Universitätsklinikum Erlangen, Medizinische Klinik 4–Nephrologie und Hypertensiologie (A.D.), and Optical Imaging Center Erlangen (OICE) (R.P.), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Anke Dahlmann
- From the Institut für Zelluläre und Molekulare Physiologie (V.N., B.K., M.B., C.K.), Universitätsklinikum Erlangen, Medizinische Klinik 4–Nephrologie und Hypertensiologie (A.D.), and Optical Imaging Center Erlangen (OICE) (R.P.), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Ralf Palmisano
- From the Institut für Zelluläre und Molekulare Physiologie (V.N., B.K., M.B., C.K.), Universitätsklinikum Erlangen, Medizinische Klinik 4–Nephrologie und Hypertensiologie (A.D.), and Optical Imaging Center Erlangen (OICE) (R.P.), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Christoph Korbmacher
- From the Institut für Zelluläre und Molekulare Physiologie (V.N., B.K., M.B., C.K.), Universitätsklinikum Erlangen, Medizinische Klinik 4–Nephrologie und Hypertensiologie (A.D.), and Optical Imaging Center Erlangen (OICE) (R.P.), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany
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Li YL, Zhang D, Tu H, Muelleman RL. Altered ENaC is Associated With Aortic Baroreceptor Dysfunction in Chronic Heart Failure. Am J Hypertens 2016; 29:582-9. [PMID: 26297031 DOI: 10.1093/ajh/hpv141] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Accepted: 07/28/2015] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Abnormal baroreceptor function contributes to attenuated arterial baroreflex sensitivity in chronic heart failure (CHF). As a mechanosensor in mammalian nonepithelium, the epithelial sodium channel (ENaC) is an amiloride-sensitive and voltage-independent ion channel. The ENaC is thought to be a component of baroreceptor mechanosensitive ion channels in aortic baroreceptor cell bodies and nerve terminals. In this study, therefore, we measured the expression and activation of the ENaC in nodose neuronal cell bodies and aortic baroreceptor nerve terminals in sham and CHF rats. METHODS AND RESULTS CHF was induced by surgical ligation of left coronary artery. The development of CHF was confirmed by hemodynamic and morphological characteristics. The aortic baroreceptor sensitivity was blunted in anesthetized CHF rats, compared with that in sham rats. The data from immunostaining and western blot analysis showed that the protein of β- and γ-ENaC subunits was expressed in nodose neuronal cell bodies and aortic baroreceptor nerve terminals, whereas the protein of α-ENaC subunit was undetectable. CHF reduced protein expression of β- and γ-ENaC subunits in nodose neuronal cell bodies and aortic baroreceptor nerve terminals. Additionally, the data recorded by the whole cell patch-clamp technique demonstrated that ENaC currents in aortic baroreceptor neurons were lower in CHF rats than that in sham rats. CONCLUSION These results suggest that reduced protein expression of the ENaC decreases the ENaC activation, which could be involved in attenuation of the aortic baroreceptor sensitivity in the CHF state. Baroreceptors should be a potential therapeutic target for reducing mortality in CHF.
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Affiliation(s)
- Yu-Long Li
- Department of Emergency Medicine, University of Nebraska Medical Center, Omaha, Nebraska, USA; Department of Cellular and integrative Physiology, University of Nebraska Medical Center, Omaha, Nebraska, USA.
| | - Dongze Zhang
- Department of Emergency Medicine, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Huiyin Tu
- Department of Emergency Medicine, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Robert L Muelleman
- Department of Emergency Medicine, University of Nebraska Medical Center, Omaha, Nebraska, USA
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Expression and distribution of epithelial sodium channel in nasal polyp and nasal mucosa. Eur Arch Otorhinolaryngol 2015; 272:3361-6. [PMID: 25559464 DOI: 10.1007/s00405-014-3477-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2014] [Accepted: 12/23/2014] [Indexed: 10/24/2022]
Abstract
To evaluate the expression and location of epithelial sodium channels (ENaCs) in human nasal polyp and normal nasal mucosa, and to characterize the relevance of ENaCs to the development of NPs. Nasal polyp tissue from 17 patients and nasal mucosa from ten patients were obtained through endoscopic sinus surgery. The mRNA concentrations of ENaC-α, β, and γ were detected by real-time polymerase chain reaction. The expression of ENaC-α was detected using western blot and immunofluorescence techniques. The distribution of ENaC-α in mucosal tissue was observed using a laser scanning confocal microscope. The transcriptional expression of three subunits of ENaC was in the following order: α > β > γ, in both groups. The transcriptional expression of α, β, and γ subunits of ENaC was elevated in nasal polyp compared to nasal mucosa (p < 0.01). ENaC-α expression was higher in nasal polyp than in nasal mucosa (p < 0.05). Immunofluorescent staining indicated that ENaC-α protein was distributed in the epithelial cell apical membrane. The expression of ENaC is upregulated in human nasal polyp, which might in turn facilitate the formation and development of nasal polyp.
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Luo Y, Xia Q, Xia Z, Tang Y. Atrial natriuretic peptide reduces the α-subunit of the epithelial sodium channel mRNA expression in the mouse stria vascularis. Biomed Rep 2014; 3:159-162. [PMID: 25798240 DOI: 10.3892/br.2014.400] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2014] [Accepted: 11/19/2014] [Indexed: 02/05/2023] Open
Abstract
Atrial natriuretic peptide (ANP) is extensively expressed in the cochlea, including the strial vascularis (StV). ANP may participate in the regulation of the water-electrolyte balance. However, the functional significance of ANP in the cochlea is less understood and little is known regarding the exact mechanisms. Studies suggest that the epithelial sodium channel (ENaC) is important for regulating sodium transport across epithelia. ENaC may be involved in the clearance of endolymphatic Na+ and maintenance of a K-rich and Na-poor composition in the endolymph. Whether ANP has a regulatory effect on the Na+ channel in the StV remains unknown. The aim of the present study was to evaluate whether ANP affects the expression of the α-subunit of the ENaC (α-ENaC) mRNA in the mouse StV, using the reverse transcription-quantitative polymerase chain reaction (RT-qPCR) technique. The mouse StV tissues were incubated with 10-6 mol/1 ANP for different times (2, 6, 12, 24 and 48 h) and were subsequently harvested. α-ENaC mRNA was extracted for RT-qPCR analysis of the expression. The study demonstrated the existence of α-ENaC in the mouse StV. Tissues treated with ANP (10-6 mol/1) showed a significant reduction in α-ENaC mRNA expression (n=3, P<0.05). A maximum effect was reached at 2 h after treatment. The present results indicate that ANP may regulate cochlear ion transport and endolymph fluid balance in the inner ear via reducing expression of the α-ENaC mRNA in the mouse StV.
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Affiliation(s)
- Yan Luo
- Department of Otorhinolaryngology and Translational Neuroscience Center, West China Hospital of Sichuan University, Chengdu, Sichuan 610041, P.R. China
| | - Qingjie Xia
- West China Laboratory of Molecular Genetics, Sichuan University, Chengdu, Sichuan 610041, P.R. China
| | - Zengliang Xia
- West China Laboratory of Molecular Genetics, Sichuan University, Chengdu, Sichuan 610041, P.R. China
| | - Yuedi Tang
- Department of Otorhinolaryngology and Translational Neuroscience Center, West China Hospital of Sichuan University, Chengdu, Sichuan 610041, P.R. China
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15
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Xu W, Hong SJ, Zeitchek M, Cooper G, Jia S, Xie P, Qureshi HA, Zhong A, Porterfield MD, Galiano RD, Surmeier DJ, Mustoe TA. Hydration status regulates sodium flux and inflammatory pathways through epithelial sodium channel (ENaC) in the skin. J Invest Dermatol 2014; 135:796-806. [PMID: 25371970 DOI: 10.1038/jid.2014.477] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Revised: 09/22/2014] [Accepted: 10/05/2014] [Indexed: 02/03/2023]
Abstract
Although it is known that the inflammatory response that results from disruption of epithelial barrier function after injury results in excessive scarring, the upstream signals remain unknown. It has also been observed that epithelial disruption results in reduced hydration status and that the use of occlusive dressings that prevent water loss from wounds decreases scar formation. We hypothesized that hydration status changes sodium homeostasis and induces sodium flux in keratinocytes, which result in activation of pathways responsible for keratinocyte-fibroblast signaling and ultimately lead to activation of fibroblasts. Here, we demonstrate that perturbations in epithelial barrier function lead to increased sodium flux in keratinocytes. We identified that sodium flux in keratinocytes is mediated by epithelial sodium channels (ENaCs) and causes increased secretion of proinflammatory cytokines, which activate fibroblast via the cyclooxygenase 2 (COX-2)/prostaglandin E2 (PGE2) pathway. Similar changes in signal transduction and sodium flux occur by increased sodium concentration, which simulates reduced hydration, in the media in epithelial cultures or human ex vivo skin cultures. Blockade of ENaC, prostaglandin synthesis, or PGE2 receptors all reduce markers of fibroblast activation and collagen synthesis. In addition, employing a validated in vivo excessive scar model in the rabbit ear, we demonstrate that utilization of either an ENaC blocker or a COX-2 inhibitor results in a marked reduction in scarring. Other experiments demonstrate that the activation of COX-2 in response to increased sodium flux is mediated through the PIK3/Akt pathway. Our results indicate that ENaC responds to small changes in sodium concentration with inflammatory mediators and suggest that the ENaC pathway is a potential target for a strategy to prevent fibrosis.
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Affiliation(s)
- Wei Xu
- Laboratory for Wound Repair and Regenerative Medicine, Department of Surgery/Plastic Surgery Division, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Seok Jong Hong
- Laboratory for Wound Repair and Regenerative Medicine, Department of Surgery/Plastic Surgery Division, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Michael Zeitchek
- Department of Agricultural and Biological Engineering, Weldon School of Biomedical Engineering, Purdue University, West Lafayette, Indiana, USA
| | - Garry Cooper
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Shengxian Jia
- Laboratory for Wound Repair and Regenerative Medicine, Department of Surgery/Plastic Surgery Division, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Ping Xie
- Laboratory for Wound Repair and Regenerative Medicine, Department of Surgery/Plastic Surgery Division, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Hannan A Qureshi
- Laboratory for Wound Repair and Regenerative Medicine, Department of Surgery/Plastic Surgery Division, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Aimei Zhong
- Laboratory for Wound Repair and Regenerative Medicine, Department of Surgery/Plastic Surgery Division, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA; Department of Plastic Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Marshall D Porterfield
- Department of Agricultural and Biological Engineering, Weldon School of Biomedical Engineering, Purdue University, West Lafayette, Indiana, USA
| | - Robert D Galiano
- Laboratory for Wound Repair and Regenerative Medicine, Department of Surgery/Plastic Surgery Division, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - D James Surmeier
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Thomas A Mustoe
- Laboratory for Wound Repair and Regenerative Medicine, Department of Surgery/Plastic Surgery Division, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA.
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16
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Li L, Wang F, Wei X, Liang Y, Cui Y, Gao F, Zhong J, Pu Y, Zhao Y, Yan Z, Arendshorst WJ, Nilius B, Chen J, Liu D, Zhu Z. Transient receptor potential vanilloid 1 activation by dietary capsaicin promotes urinary sodium excretion by inhibiting epithelial sodium channel α subunit-mediated sodium reabsorption. Hypertension 2014; 64:397-404. [PMID: 24890824 DOI: 10.1161/hypertensionaha.114.03105] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
High salt (HS) intake contributes to the development of hypertension. Epithelial sodium channels play crucial roles in regulating renal sodium reabsorption and blood pressure. The renal transient receptor potential vanilloid 1 (TRPV1) cation channel can be activated by its agonist capsaicin. However, it is unknown whether dietary factors can act on urinary sodium excretion and renal epithelial sodium channel (ENaC) function. Here, we report that TRPV1 activation by dietary capsaicin increased urinary sodium excretion through reducing sodium reabsorption in wild-type (WT) mice on a HS diet but not in TRPV1(-/-) mice. The effect of capsaicin on urinary sodium excretion was involved in inhibiting αENaC and its related with-no-lysine kinase 1/serum- and glucocorticoid-inducible protein kinase 1 pathway in renal cortical collecting ducts of WT mice. Dietary capsaicin further reduced the increased αENaC activity in WT mice attributed to the HS diet. In contrast, this capsaicin effect was absent in TRPV1(-/-) mice. Immunoprecipitation study indicated αENaC specifically coexpressed and functionally interact with TRPV1 in renal cortical collecting ducts of WT mice. Additionally, ENaC activity and expression were suppressed by capsaicin-mediated TRPV1 activation in cultured M1-cortical collecting duct cells. Long-term dietary capsaicin prevented the development of high blood pressure in WT mice on a HS diet. It concludes that TRPV1 activation in the cortical collecting ducts by capsaicin increases urinary sodium excretion and avoids HS diet-induced hypertension through antagonizing αENaC-mediated urinary sodium reabsorption. Dietary capsaicin may represent a promising lifestyle intervention in populations exposed to a high dietary salt intake.
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Affiliation(s)
- Li Li
- From the Department of Hypertension and Endocrinology, Center for Hypertension and Metabolic Diseases, Daping Hospital, Third Military Medical University, Chongqing Institute of Hypertension, Chongqing, China (L.L., F.W., X.W., Y.L., Y.C., F.G., J.Z., Y.P., Y.Z., Z.Y., J.C., D.L., Z.Z.); Department of Cell Biology and Physiology, School of Medicine, University of North Carolina at Chapel Hill (W.J.A.); and Department of Cell Molecular Medicine, Laboratory Ion Channel Research, Campus Gasthuisberg, Leuven, Belgium (B.N.)
| | - Fei Wang
- From the Department of Hypertension and Endocrinology, Center for Hypertension and Metabolic Diseases, Daping Hospital, Third Military Medical University, Chongqing Institute of Hypertension, Chongqing, China (L.L., F.W., X.W., Y.L., Y.C., F.G., J.Z., Y.P., Y.Z., Z.Y., J.C., D.L., Z.Z.); Department of Cell Biology and Physiology, School of Medicine, University of North Carolina at Chapel Hill (W.J.A.); and Department of Cell Molecular Medicine, Laboratory Ion Channel Research, Campus Gasthuisberg, Leuven, Belgium (B.N.)
| | - Xing Wei
- From the Department of Hypertension and Endocrinology, Center for Hypertension and Metabolic Diseases, Daping Hospital, Third Military Medical University, Chongqing Institute of Hypertension, Chongqing, China (L.L., F.W., X.W., Y.L., Y.C., F.G., J.Z., Y.P., Y.Z., Z.Y., J.C., D.L., Z.Z.); Department of Cell Biology and Physiology, School of Medicine, University of North Carolina at Chapel Hill (W.J.A.); and Department of Cell Molecular Medicine, Laboratory Ion Channel Research, Campus Gasthuisberg, Leuven, Belgium (B.N.)
| | - Yi Liang
- From the Department of Hypertension and Endocrinology, Center for Hypertension and Metabolic Diseases, Daping Hospital, Third Military Medical University, Chongqing Institute of Hypertension, Chongqing, China (L.L., F.W., X.W., Y.L., Y.C., F.G., J.Z., Y.P., Y.Z., Z.Y., J.C., D.L., Z.Z.); Department of Cell Biology and Physiology, School of Medicine, University of North Carolina at Chapel Hill (W.J.A.); and Department of Cell Molecular Medicine, Laboratory Ion Channel Research, Campus Gasthuisberg, Leuven, Belgium (B.N.)
| | - Yuanting Cui
- From the Department of Hypertension and Endocrinology, Center for Hypertension and Metabolic Diseases, Daping Hospital, Third Military Medical University, Chongqing Institute of Hypertension, Chongqing, China (L.L., F.W., X.W., Y.L., Y.C., F.G., J.Z., Y.P., Y.Z., Z.Y., J.C., D.L., Z.Z.); Department of Cell Biology and Physiology, School of Medicine, University of North Carolina at Chapel Hill (W.J.A.); and Department of Cell Molecular Medicine, Laboratory Ion Channel Research, Campus Gasthuisberg, Leuven, Belgium (B.N.)
| | - Feng Gao
- From the Department of Hypertension and Endocrinology, Center for Hypertension and Metabolic Diseases, Daping Hospital, Third Military Medical University, Chongqing Institute of Hypertension, Chongqing, China (L.L., F.W., X.W., Y.L., Y.C., F.G., J.Z., Y.P., Y.Z., Z.Y., J.C., D.L., Z.Z.); Department of Cell Biology and Physiology, School of Medicine, University of North Carolina at Chapel Hill (W.J.A.); and Department of Cell Molecular Medicine, Laboratory Ion Channel Research, Campus Gasthuisberg, Leuven, Belgium (B.N.)
| | - Jian Zhong
- From the Department of Hypertension and Endocrinology, Center for Hypertension and Metabolic Diseases, Daping Hospital, Third Military Medical University, Chongqing Institute of Hypertension, Chongqing, China (L.L., F.W., X.W., Y.L., Y.C., F.G., J.Z., Y.P., Y.Z., Z.Y., J.C., D.L., Z.Z.); Department of Cell Biology and Physiology, School of Medicine, University of North Carolina at Chapel Hill (W.J.A.); and Department of Cell Molecular Medicine, Laboratory Ion Channel Research, Campus Gasthuisberg, Leuven, Belgium (B.N.)
| | - Yunfei Pu
- From the Department of Hypertension and Endocrinology, Center for Hypertension and Metabolic Diseases, Daping Hospital, Third Military Medical University, Chongqing Institute of Hypertension, Chongqing, China (L.L., F.W., X.W., Y.L., Y.C., F.G., J.Z., Y.P., Y.Z., Z.Y., J.C., D.L., Z.Z.); Department of Cell Biology and Physiology, School of Medicine, University of North Carolina at Chapel Hill (W.J.A.); and Department of Cell Molecular Medicine, Laboratory Ion Channel Research, Campus Gasthuisberg, Leuven, Belgium (B.N.)
| | - Yu Zhao
- From the Department of Hypertension and Endocrinology, Center for Hypertension and Metabolic Diseases, Daping Hospital, Third Military Medical University, Chongqing Institute of Hypertension, Chongqing, China (L.L., F.W., X.W., Y.L., Y.C., F.G., J.Z., Y.P., Y.Z., Z.Y., J.C., D.L., Z.Z.); Department of Cell Biology and Physiology, School of Medicine, University of North Carolina at Chapel Hill (W.J.A.); and Department of Cell Molecular Medicine, Laboratory Ion Channel Research, Campus Gasthuisberg, Leuven, Belgium (B.N.)
| | - Zhencheng Yan
- From the Department of Hypertension and Endocrinology, Center for Hypertension and Metabolic Diseases, Daping Hospital, Third Military Medical University, Chongqing Institute of Hypertension, Chongqing, China (L.L., F.W., X.W., Y.L., Y.C., F.G., J.Z., Y.P., Y.Z., Z.Y., J.C., D.L., Z.Z.); Department of Cell Biology and Physiology, School of Medicine, University of North Carolina at Chapel Hill (W.J.A.); and Department of Cell Molecular Medicine, Laboratory Ion Channel Research, Campus Gasthuisberg, Leuven, Belgium (B.N.)
| | - William J Arendshorst
- From the Department of Hypertension and Endocrinology, Center for Hypertension and Metabolic Diseases, Daping Hospital, Third Military Medical University, Chongqing Institute of Hypertension, Chongqing, China (L.L., F.W., X.W., Y.L., Y.C., F.G., J.Z., Y.P., Y.Z., Z.Y., J.C., D.L., Z.Z.); Department of Cell Biology and Physiology, School of Medicine, University of North Carolina at Chapel Hill (W.J.A.); and Department of Cell Molecular Medicine, Laboratory Ion Channel Research, Campus Gasthuisberg, Leuven, Belgium (B.N.)
| | - Bernd Nilius
- From the Department of Hypertension and Endocrinology, Center for Hypertension and Metabolic Diseases, Daping Hospital, Third Military Medical University, Chongqing Institute of Hypertension, Chongqing, China (L.L., F.W., X.W., Y.L., Y.C., F.G., J.Z., Y.P., Y.Z., Z.Y., J.C., D.L., Z.Z.); Department of Cell Biology and Physiology, School of Medicine, University of North Carolina at Chapel Hill (W.J.A.); and Department of Cell Molecular Medicine, Laboratory Ion Channel Research, Campus Gasthuisberg, Leuven, Belgium (B.N.)
| | - Jing Chen
- From the Department of Hypertension and Endocrinology, Center for Hypertension and Metabolic Diseases, Daping Hospital, Third Military Medical University, Chongqing Institute of Hypertension, Chongqing, China (L.L., F.W., X.W., Y.L., Y.C., F.G., J.Z., Y.P., Y.Z., Z.Y., J.C., D.L., Z.Z.); Department of Cell Biology and Physiology, School of Medicine, University of North Carolina at Chapel Hill (W.J.A.); and Department of Cell Molecular Medicine, Laboratory Ion Channel Research, Campus Gasthuisberg, Leuven, Belgium (B.N.)
| | - Daoyan Liu
- From the Department of Hypertension and Endocrinology, Center for Hypertension and Metabolic Diseases, Daping Hospital, Third Military Medical University, Chongqing Institute of Hypertension, Chongqing, China (L.L., F.W., X.W., Y.L., Y.C., F.G., J.Z., Y.P., Y.Z., Z.Y., J.C., D.L., Z.Z.); Department of Cell Biology and Physiology, School of Medicine, University of North Carolina at Chapel Hill (W.J.A.); and Department of Cell Molecular Medicine, Laboratory Ion Channel Research, Campus Gasthuisberg, Leuven, Belgium (B.N.)
| | - Zhiming Zhu
- From the Department of Hypertension and Endocrinology, Center for Hypertension and Metabolic Diseases, Daping Hospital, Third Military Medical University, Chongqing Institute of Hypertension, Chongqing, China (L.L., F.W., X.W., Y.L., Y.C., F.G., J.Z., Y.P., Y.Z., Z.Y., J.C., D.L., Z.Z.); Department of Cell Biology and Physiology, School of Medicine, University of North Carolina at Chapel Hill (W.J.A.); and Department of Cell Molecular Medicine, Laboratory Ion Channel Research, Campus Gasthuisberg, Leuven, Belgium (B.N.).
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17
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West CA, Han W, Li N, Masilamani SME. Renal epithelial sodium channel is critical for blood pressure maintenance and sodium balance in the normal late pregnant rat. Exp Physiol 2014; 99:816-23. [PMID: 24563165 DOI: 10.1113/expphysiol.2013.076273] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Normal pregnancy is a state marked by avid sodium retention and plasma volume expansion. Insufficient plasma volume expansion results in the compromised maternal state of intrauterine growth restriction, which afflicts ∼5% of all human pregnancies. We have recently shown that renal epithelial sodium channel (ENaC) activity in vivo in the late pregnant (LP) rat is increased. To determine the importance of the renal versus extrarenal ENaC in sodium retention and blood pressure regulation during pregnancy, we have chronically blocked the ENaC pharmacologically with daily subcutaneous injections of benzamil and genetically using intrarenal transfection of αENaC short hairpin RNA. Compared with untreated LP control animals, LP rats treated with benzamil retain less sodium and have reduced mean arterial blood pressure. Furthermore, LP rats treated with benzamil had lower maternal body weight gain. Intrarenal transfection of αENaC short hairpin RNA versus scrambled small RNA successfully decreased renal αENaC mRNA expression in LP rats. Intrarenal transfection of αENaC short hairpin RNA reduced maternal sodium retention, body weight gain and pup weight. Redundant physiological systems that protect blood pressure and sodium homeostasis were unable to compensate for the loss of ENaC activity in the pregnant rat. These findings demonstrate that the renal ENaC is necessary for maintaining pregnancy-mediated sodium retention, volume expansion and blood pressure regulation.
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Affiliation(s)
- Crystal A West
- Department of Physiology & Biophysics, Virginia Commonwealth University Medical Center, Richmond, VA, USA
| | - Weiquing Han
- Department of Pharmacology & Toxicology, Virginia Commonwealth University Medical Center, Richmond, VA, USA
| | - Ningjun Li
- Department of Pharmacology & Toxicology, Virginia Commonwealth University Medical Center, Richmond, VA, USA
| | - Shyama M E Masilamani
- Department of Physiology & Biophysics, Virginia Commonwealth University Medical Center, Richmond, VA, USA Department of Internal Medicine, Virginia Commonwealth University Medical Center, Richmond, VA, USA Department of Physiology & Pharmacology, West Virginia University School of Medicine, Morgantown, WV, USA
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18
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Markadieu N, Delpire E. Physiology and pathophysiology of SLC12A1/2 transporters. Pflugers Arch 2014; 466:91-105. [PMID: 24097229 PMCID: PMC3877717 DOI: 10.1007/s00424-013-1370-5] [Citation(s) in RCA: 86] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2013] [Revised: 09/21/2013] [Accepted: 09/23/2013] [Indexed: 01/14/2023]
Abstract
The electroneutral Na(+)-K(+)-Cl(-) cotransporters NKCC1 (encoded by the SLC12A2 gene) and NKCC2 (SLC12A1 gene) belong to the Na(+)-dependent subgroup of solute carrier 12 (SLC12) family of transporters. They mediate the electroneutral movement of Na(+) and K(+), tightly coupled to the movement of Cl(-) across cell membranes. As they use the energy of the ion gradients generated by the Na(+)/K(+)-ATPase to transport Na(+), K(+), and Cl(-) from the outside to the inside of a cell, they are considered secondary active transport mechanisms. NKCC-mediated transport occurs in a 1Na(+), 1K(+), and 2Cl(-) ratio, although NKCC1 has been shown to sometimes mediate partial reactions. Both transporters are blocked by bumetanide and furosemide, drugs which are commonly used in clinical medicine. NKCC2 is the molecular target of loop diuretics as it is expressed on the apical membrane of thick ascending limb of Henle epithelial cells, where it mediates NaCl reabsorption. NKCC1, in contrast, is found on the basolateral membrane of Cl(-) secretory epithelial cells, as well as in a variety of non-epithelial cells, where it mediates cell volume regulation and participates in Cl(-) homeostasis. Following their molecular identification two decades ago, much has been learned about their biophysical properties, their mode of operation, their regulation by kinases and phosphatases, and their physiological relevance. However, despite this tremendous amount of new information, there are still so many gaps in our knowledge. This review summarizes information that constitutes consensus in the field, but it also discusses current points of controversy and highlights many unanswered questions.
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Affiliation(s)
- Nicolas Markadieu
- Department of Anesthesiology, Vanderbilt University School of Medicine, MCN T-4202, 1161 21st Avenue South, Nashville, TN, 37232, USA
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West CA, Shaw S, Sasser JM, Fekete A, Alexander T, Cunningham MW, Masilamani SME, Baylis C. Chronic vasodilation increases renal medullary PDE5A and α-ENaC through independent renin-angiotensin-aldosterone system pathways. Am J Physiol Regul Integr Comp Physiol 2013; 305:R1133-40. [PMID: 24068049 PMCID: PMC3841800 DOI: 10.1152/ajpregu.00003.2013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2013] [Accepted: 09/19/2013] [Indexed: 02/05/2023]
Abstract
We have previously observed that many of the renal and hemodynamic adaptations seen in normal pregnancy can be induced in virgin female rats by chronic systemic vasodilation. Fourteen-day vasodilation with sodium nitrite or nifedipine (NIF) produced plasma volume expansion (PVE), hemodilution, and increased renal medullary phosphodiesterase 5A (PDE5A) protein. The present study examined the role of the renin-angiotensin-aldosterone system (RAAS) in this mechanism. Virgin females were treated for 14 days with NIF (10 mg·kg(-1)·day(-1) via diet), NIF with spironolactone [SPR; mineralocorticoid receptor (MR) blocker, 200-300 mg·kg(-1)·day(-1) via diet], NIF with losartan [LOS; angiotensin type 1 (AT1) receptor blocker, 20 mg·kg(-1)·day(-1) via diet], enalapril (ENAL; angiotensin-converting enzyme inhibitor, 62.5 mg/l via water), or vehicle (CON). Mean arterial pressure (MAP) was reduced 7.4 ± 0.5% with NIF, 6.33 ± 0.5% with NIF + SPR, 13.3 ± 0.9% with NIF + LOS, and 12.0 ± 0.4% with ENAL vs. baseline MAP. Compared with CON (3.6 ± 0.3%), plasma volume factored for body weight was increased by NIF (5.2 ± 0.4%) treatment but not by NIF + SPR (4.3 ± 0.3%), NIF + LOS (3.6 ± 0.1%), or ENAL (4.0 ± 0.3%). NIF increased PDE5A protein abundance in the renal inner medulla, and SPR did not prevent this increase (188 ± 16 and 204 ± 22% of CON, respectively). NIF increased the α-subunit of the epithelial sodium channel (α-ENaC) protein in renal outer (365 ± 44%) and inner (526 ± 83%) medulla, and SPR prevented these changes. There was no change in either PDE5A or α-ENaC abundance vs. CON in rats treated with NIF + LOS or ENAL. These data indicate that the PVE and renal medullary adaptations in response to chronic vasodilation result from RAAS signaling, with increases in PDE5A mediated through AT1 receptor and α-ENaC through the MR.
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Affiliation(s)
- Crystal A West
- Department of Physiology and Functional Genomics, University of Florida, Gainesville, Florida
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20
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ENaC γ-expressing astrocytes in the circumventricular organs, white matter, and ventral medullary surface: sites for Na+ regulation by glial cells. J Chem Neuroanat 2013; 53:72-80. [PMID: 24145067 DOI: 10.1016/j.jchemneu.2013.10.002] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Accepted: 10/02/2013] [Indexed: 12/19/2022]
Abstract
Using a double immunofluorescence procedure, we report the discovery of a novel group of fibrous astrocytes that co-express epithelial sodium channel (ENaC) γ-subunit protein along with glial acidic fibrillary protein (GFAP). These cells are concentrated along the borders of the sensory circumventricular organs (CVOs), embedded in the white matter (e.g., optic nerve/chiasm, anterior commissure, corpus callosum, pyramidal tract) and are components of the pia mater. In the CVOs, a compact collection of ENaC γ-immunoreactive glial fibers form the lamina terminalis immediately rostral to the organum vasculosum of the lamina terminalis (OVLT). Astrocyte processes can be traced into the median preoptic nucleus - a region implicated in regulation of sodium homeostasis. In the subfornical organ (SFO), ENaC γ-GFAP astrocytes lie in its lateral border, but not in the ventromedial core. In the area postrema (AP), a dense ENaC γ-GFAP glial fibers form the interface between the AP and nucleus tractus solitarius; this area is termed the subpostremal region. Antibodies against the ENaC α- or β-subunit proteins do not immunostain these regions. In contrast, the antibodies against the ENaC γ-subunit protein react weakly with neuronal cell bodies in the CVOs. Besides affecting glial-neural functions in the CVOs, the astrocytes found in the white matter may affect saltatory nerve conduction, serving as a sodium buffer. The ENaC γ-expressing astrocytes of the ventral medulla send processes into the raphe pallidus which intermingle with the serotoninergic (5-HT) neurons found in this region as well as with the other nearby 5-HT neurons distributed along ventral medullary surface.
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22
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Warnock DG, Rossier BC. Renal Sodium Handling: The Role of the Epithelial Sodium Channel. J Am Soc Nephrol 2005; 16:3151-3. [PMID: 16192426 DOI: 10.1681/asn.2005080886] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Affiliation(s)
- David G Warnock
- Nephrology Research and Training Center, Department of Medicine, University of Alabama at Birmingham, Alabama 35294-0006, USA.
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