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Johnsen LØ, Friis KA, Møller-Madsen MK, Damkier HH. Mechanisms of cerebrospinal fluid secretion by the choroid plexus epithelium: Application to various intracranial pathologies. Clin Anat 2024. [PMID: 38894645 DOI: 10.1002/ca.24199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2024] [Revised: 06/02/2024] [Accepted: 06/06/2024] [Indexed: 06/21/2024]
Abstract
The choroid plexus (CP) is a small yet highly active epithelial tissue located in the ventricles of the brain. It secretes most of the CSF that envelops the brain and spinal cord. The epithelial cells of the CP have a high fluid secretion rate and differ from many other secretory epithelia in the organization of several key ion transporters. One striking difference is the luminal location of, for example, the vital Na+-K+-ATPase. In recent years, there has been a renewed focus on the role of ion transporters in CP secretion. Several studies have indicated that increased membrane transport activity is implicated in disorders such as hydrocephalus, idiopathic intracranial hypertension, and posthemorrhagic sequelae. The importance of the CP membrane transporters in regulating the composition of the CSF has also been a focus in research in recent years, particularly as a regulator of breathing and hemodynamic parameters such as blood pressure. This review focuses on the role of the fundamental ion transporters involved in CSF secretion and its ion composition. It gives a brief overview of the established factors and controversies concerning ion transporters, and finally discusses future perspectives related to the role of these transporters in the CP epithelium.
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Elgazzaz M, Lakkappa N, Berdasco C, Mohan UP, Nuzzo A, Restivo L, Martinez A, Scarborough A, Guidry JJ, Sriramula S, Xu J, Daoud H, Mendiola Plá MA, Bowles DE, Beyer AM, Mauvais-Jarvis F, Yue X, Filipeanu CM, Lazartigues E. UBR1 Promotes Sex-Dependent ACE2 Ubiquitination in Hypertension. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2024:2024.05.23.24307722. [PMID: 38826318 PMCID: PMC11142264 DOI: 10.1101/2024.05.23.24307722] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2024]
Abstract
Background Angiotensin (Ang)-II impairs the function of the antihypertensive enzyme ACE2 by promoting its internalization, ubiquitination and degradation thus contributing to hypertension. However, few ACE2 ubiquitination partners have been identified and their role in hypertension remains unknown. Methods Proteomics and bioinformatic analysis were used to identify ACE2 ubiquitination partners in the brain, heart, and kidney from Ang-II-infused C57BL6/J mice from both sexes and validated the interaction between UBR1 and ACE2 in cells. Central and peripheral UBR1 knockdown was then performed in male mice to investigate its role in the maintenance of hypertension. Results Proteomics analysis from hypothalamus identified UBR1 as a potential E3 ligase promoting ACE2 ubiquitination. Enhanced UBR1 expression, associated with ACE2 reduction, was confirmed in various tissues from hypertensive male mice and human samples. Treatment of endothelial and smooth muscle cells with testosterone, but not 17β-estradiol, confirmed a sex-specific regulation of UBR1. In vivo silencing of UBR1 using chronic administration of small interference RNA resulted in the restoration of ACE2 levels in hypertensive males. A transient decrease in blood pressure following intracerebroventricular, but not systemic, infusion was also observed. Interestingly, UBR1 knockdown increased the brain activation of Nedd4-2, an E3 ligase promoting ACE2 ubiquitination and reduced expression of SGK1, the kinase inactivating Nedd4-2. Conclusions: These data demonstrate that UBR1 is a novel ubiquitin ligase targeting ACE2 in hypertension. UBR1 and Nedd4-2 E3 ligases appear to work synergistically to ubiquitinate ACE2. Targeting of these ubiquitin ligases may represent a novel strategy to restore ACE2 compensatory activity in hypertension.
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Rotin D, Prag G. Physiological Functions of the Ubiquitin Ligases Nedd4-1 and Nedd4-2. Physiology (Bethesda) 2024; 39:18-29. [PMID: 37962894 DOI: 10.1152/physiol.00023.2023] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2023] [Revised: 11/13/2023] [Accepted: 11/13/2023] [Indexed: 11/15/2023] Open
Abstract
The Nedd4 family of E3 ubiquitin ligases, consisting of a C2-WW(n)-HECT domain architecture, includes the closely related Nedd4/Nedd4-1 and Nedd4L/Nedd4-2, which play critical roles in human physiology and pathophysiology.This review focuses on the regulation of enzymatic activity of these Nedd4 proteins, as well as on their roles in regulating stability and function of membrane and other signaling proteins, such as ion channels, ion transporters, and growth factor receptors. The diseases caused by impairment of such regulation are discussed, as well as opportunities and challenges for targeting these enzymes for therapy.
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Affiliation(s)
- Daniela Rotin
- Cell Biology Program, The Hospital for Sick Children, Toronto, Ontario, Canada
- Biochemistry Department, University of Toronto, Ontario, Canada
| | - Gali Prag
- School of Neurobiology, Biochemistry and Biophysics, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Israel
- Sagol School of Neuroscience, Tel Aviv University, Israel
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Heusser K, Tank J, Diedrich A, Fischer A, Heise T, Jordan J. Randomized Trial Comparing SGLT2 Inhibition and Hydrochlorothiazide on Sympathetic Traffic in Type 2 Diabetes. Kidney Int Rep 2023; 8:2254-2264. [PMID: 38025218 PMCID: PMC10658269 DOI: 10.1016/j.ekir.2023.08.036] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Revised: 08/24/2023] [Accepted: 08/28/2023] [Indexed: 12/01/2023] Open
Abstract
Introduction Reductions in sympathetic nervous system activity may contribute to beneficial effects of sodium glucose cotransporter 2 (SGLT2) inhibition on cardiovascular outcomes. Therefore, we tested the hypothesis that SGLT2 inhibition with empagliflozin (Empa) lowers muscle sympathetic nerve activity (MSNA) in patients with type 2 diabetes mellitus (T2DM) compared with hydrochlorothiazide (HCT) to discern SGLT2-specific actions from responses to increased natriuresis. Methods We randomized patients with T2DM on metformin monotherapy to either 25 mg/d Empa (n = 20) or 25 mg/d HCT (n = 21) for 6 weeks in a parallel, double-blind fashion. We assessed MSNA by peroneal microneurography, blood pressure, cardiovascular and metabolic biomarkers at baseline and at the end of treatment. Results Both drugs elicited volume depletion, as indicated by increased thoracic impedance. Compared with HCT, Empa caused 1.23 kg more body weight loss (P = 0.011) and improved glycemic control. Seated systolic blood pressure decreased with both treatments (P < 0.002). MSNA did not change significantly with either treatment; however, MSNA changes were negatively correlated with changes in body weight on Empa (P = 0.042) and on HCT(P = 0.001). The relationship was shifted to lower MSNA on Empa compared with HCT (P = 0.002). Conclusion Increased renal sodium excretion eliciting body weight loss may promote sympathetic activation. However, sympathetic excitation in the face of increased sodium loss may be attenuated by SGLT2 inhibitor-specific actions.
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Affiliation(s)
- Karsten Heusser
- Institute of Aerospace Medicine, German Aerospace Center, Cologne Germany
| | - Jens Tank
- Institute of Aerospace Medicine, German Aerospace Center, Cologne Germany
| | - André Diedrich
- Vanderbilt Autonomic Dysfunction Center, Division of Clinical Pharmacology, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Department of Biomedical Engineering, School of Engineering, Vanderbilt University, Nashville, Tennessee, USA
| | | | | | - Jens Jordan
- Institute of Aerospace Medicine, German Aerospace Center, Cologne Germany
- Medical Faculty, University of Cologne, Cologne, Germany
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Mohammed M, Ogunlade B, Elgazzaz M, Berdasco C, Lakkappa N, Ghita I, Guidry JJ, Sriramula S, Xu J, Restivo L, Mendiola Plá MA, Bowles DE, Beyer AM, Yue X, Lazartigues E, Filipeanu CM. Nedd4-2 up-regulation is associated with ACE2 ubiquitination in hypertension. Cardiovasc Res 2023; 119:2130-2141. [PMID: 37161607 PMCID: PMC10478751 DOI: 10.1093/cvr/cvad070] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Revised: 03/09/2023] [Accepted: 03/30/2023] [Indexed: 05/11/2023] Open
Abstract
AIMS Angiotensin-converting enzyme 2 (ACE2) is a critical component of the compensatory renin-angiotensin system that is down-regulated during the development of hypertension, possibly via ubiquitination. However, little is known about the mechanisms involved in ACE2 ubiquitination in neurogenic hypertension. This study aimed at identifying ACE2 ubiquitination partners, establishing causal relationships and clinical relevance, and testing a gene therapy strategy to mitigate ACE2 ubiquitination in neurogenic hypertension. METHODS AND RESULTS Bioinformatics and proteomics were combined to identify E3 ubiquitin ligases associated with ACE2 ubiquitination in chronically hypertensive mice. In vitro gain/loss of function experiments assessed ACE2 expression and activity to validate the interaction between ACE2 and the identified E3 ligase. Mutation experiments were further used to generate a ubiquitination-resistant ACE2 mutant (ACE2-5R). Optogenetics, blood pressure telemetry, pharmacological blockade of GABAA receptors in mice expressing ACE2-5R in the bed nucleus of the stria terminalis (BNST), and capillary western analysis were used to assess the role of ACE2 ubiquitination in neurogenic hypertension. Ubiquitination was first validated as leading to ACE2 down-regulation, and Neural precursor cell-expressed developmentally down-regulated protein 4-2 (Nedd4-2) was identified as a E3 ligase up-regulated in hypertension and promoting ACE2 ubiquitination. Mutation of lysine residues in the C-terminal of ACE2 was associated with increased activity and resistance to angiotensin (Ang)-II-mediated degradation. Mice transfected with ACE2-5R in the BNST exhibited enhanced GABAergic input to the paraventricular nucleus (PVN) and a reduction in hypertension. ACE2-5R expression was associated with reduced Nedd4-2 levels in the BNST. CONCLUSION Our data identify Nedd4-2 as the first E3 ubiquitin ligase involved in ACE2 ubiquitination in Ang-II-mediated hypertension. We demonstrate the pivotal role of ACE2 on GABAergic neurons in the maintenance of an inhibitory tone to the PVN and the regulation of pre-sympathetic activity. These findings provide a new working model where Nedd4-2 could contribute to ACE2 ubiquitination, leading to the development of neurogenic hypertension and highlighting potential novel therapeutic strategies.
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Affiliation(s)
- Mazher Mohammed
- Southeast Louisiana Veterans Health Care System, 2400 Canal Street, New Orleans, LA 70119, USA
- Department of Pharmacology & Experimental Therapeutics, Louisiana State University Health Sciences Center, 1900 Perdido Street New Orleans, LA 70112, USA
| | - Blessing Ogunlade
- Department of Pharmacology, School of Medicine, Howard University, 520 W St, NW, Washington, DC 20059, USA
| | - Mona Elgazzaz
- Southeast Louisiana Veterans Health Care System, 2400 Canal Street, New Orleans, LA 70119, USA
- Department of Pharmacology & Experimental Therapeutics, Louisiana State University Health Sciences Center, 1900 Perdido Street New Orleans, LA 70112, USA
- Cardiovascular Center of Excellence, Louisiana State University Health Sciences Center, 533 Bolivar Street, New Orleans, LA 70112, USA
- Genetics Unit, Department of Histology and Cell Biology, Faculty of Medicine, Suez Canal University, Ismailia, Egypt
| | - Clara Berdasco
- Southeast Louisiana Veterans Health Care System, 2400 Canal Street, New Orleans, LA 70119, USA
- Department of Pharmacology & Experimental Therapeutics, Louisiana State University Health Sciences Center, 1900 Perdido Street New Orleans, LA 70112, USA
| | - Navya Lakkappa
- Southeast Louisiana Veterans Health Care System, 2400 Canal Street, New Orleans, LA 70119, USA
- Department of Pharmacology & Experimental Therapeutics, Louisiana State University Health Sciences Center, 1900 Perdido Street New Orleans, LA 70112, USA
| | - Ioana Ghita
- Department of Oncology and Diagnostic Sciences, School of Dentistry, University of Maryland, Baltimore, MD 21201, USA
| | - Jessie J Guidry
- Department of Pharmacology & Experimental Therapeutics, Louisiana State University Health Sciences Center, 1900 Perdido Street New Orleans, LA 70112, USA
| | - Srinivas Sriramula
- Department of Pharmacology & Experimental Therapeutics, Louisiana State University Health Sciences Center, 1900 Perdido Street New Orleans, LA 70112, USA
- Department of Pharmacology and Toxicology, Brody School of Medicine at East Carolina University, Greenville, NC 27834, USA
| | - Jiaxi Xu
- Department of Pharmacology & Experimental Therapeutics, Louisiana State University Health Sciences Center, 1900 Perdido Street New Orleans, LA 70112, USA
- Department of Physiology and Pathophysiology, Xi’an Jiaotong University, School of Medicine, Xi’an, 710061, China
| | - Luke Restivo
- Cardiovascular Center of Excellence, Louisiana State University Health Sciences Center, 533 Bolivar Street, New Orleans, LA 70112, USA
| | - Michelle A Mendiola Plá
- Division of Surgical Sciences, Department of Surgery, Duke University, Durham, NC 27710, USA
| | - Dawn E Bowles
- Division of Surgical Sciences, Department of Surgery, Duke University, Durham, NC 27710, USA
| | - Andreas M Beyer
- Department of Medicine, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Xinping Yue
- Cardiovascular Center of Excellence, Louisiana State University Health Sciences Center, 533 Bolivar Street, New Orleans, LA 70112, USA
- Department of Physiology, Louisiana State University Health Sciences Center, New Orleans, LA 70112, USA
| | - Eric Lazartigues
- Southeast Louisiana Veterans Health Care System, 2400 Canal Street, New Orleans, LA 70119, USA
- Department of Pharmacology & Experimental Therapeutics, Louisiana State University Health Sciences Center, 1900 Perdido Street New Orleans, LA 70112, USA
- Cardiovascular Center of Excellence, Louisiana State University Health Sciences Center, 533 Bolivar Street, New Orleans, LA 70112, USA
- Neuroscience Center of Excellence, Louisiana State University Health Sciences Center, 2020 Gravier Street, New Orleans LA 70112, USA
| | - Catalin M Filipeanu
- Department of Pharmacology, School of Medicine, Howard University, 520 W St, NW, Washington, DC 20059, USA
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Vinaiphat A, Pazhanchamy K, JebaMercy G, Ngan SC, Leow MKS, Ho HH, Gao YG, Lim KL, Richards AM, de Kleijn DPV, Chen CP, Kalaria RN, Liu J, O'Leary DD, McCarthy NE, Sze SK. Endothelial Damage Arising From High Salt Hypertension Is Elucidated by Vascular Bed Systematic Profiling. Arterioscler Thromb Vasc Biol 2023; 43:427-442. [PMID: 36700429 DOI: 10.1161/atvbaha.122.318439] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Accepted: 01/12/2023] [Indexed: 01/27/2023]
Abstract
BACKGROUND Considerable evidence links dietary salt intake with the development of hypertension, left ventricular hypertrophy, and increased risk of stroke and coronary heart disease. Despite extensive epidemiological and basic science interrogation of the relationship between high salt (HS) intake and blood pressure, it remains unclear how HS impacts endothelial cell (EC) and vascular structure in vivo. This study aims to elucidate HS-induced vascular pathology using a differential systemic decellularization in vivo approach. METHODS We performed systematic molecular characterization of the endothelial glycocalyx and EC proteomes in mice with HS (8%) diet-induced hypertension versus healthy control animals. Isolation of eGC and EC compartments was achieved using differential systemic decellularization in vivo methodology. Altered protein expression in hypertensive compared to normal mice was characterized by liquid chromatography tandem mass spectrometry. Proteomic results were validated using functional assays, microscopic imaging, and histopathologic evaluation. RESULTS Proteomic analysis revealed a significant downregulation of eGC and associated proteins in HS diet-induced hypertensive mice (among 1696 proteins identified in this group, 723 were markedly decreased in abundance, while only 168 were increased in abundance. Bioinformatic analysis indicated substantial derangement of the eGC layer, which was subsequently confirmed by fluorescent and electron microscopy assessment of vessel damage ex vivo. In the EC fraction, HS-induced hypertension significantly altered protein mediators of contractility, metabolism, mechanotransduction, renal function, and the coagulation cascade. In particular, we observed dysregulation of integrin subunits α2, α2b, and α5, which was associated with arterial wall inflammation and substantial infiltration of CD68+ monocyte-macrophages. Consequently, HS-induced hypertensive mice also displayed reduced vascular integrity of multiple organs including lungs, kidneys, and heart. CONCLUSIONS These findings provide novel molecular insight into HS-induced structural changes in eGC and EC composition that may increase cardiovascular risk and potentially guide the development of new diagnostics and therapeutic interventions.
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Affiliation(s)
- Arada Vinaiphat
- School of Biological Sciences (A.V., K.P., G.J., S.C.N., Y.-G.G., S.K.S.), Nanyang Technological University, Singapore
| | - Kalailingam Pazhanchamy
- School of Biological Sciences (A.V., K.P., G.J., S.C.N., Y.-G.G., S.K.S.), Nanyang Technological University, Singapore
| | - Gnanasekaran JebaMercy
- School of Biological Sciences (A.V., K.P., G.J., S.C.N., Y.-G.G., S.K.S.), Nanyang Technological University, Singapore
| | - SoFong Cam Ngan
- School of Biological Sciences (A.V., K.P., G.J., S.C.N., Y.-G.G., S.K.S.), Nanyang Technological University, Singapore
- Department of Health Sciences, Faculty of Applied Health Sciences, Brock University, St. Catharines, ON, Canada (S.C.N., J.L., D.D.O., S.K.S.)
| | - Melvin Khee-Shing Leow
- Lee Kong Chian School of Medicine (M.K.-S.L., K.L.L.), Nanyang Technological University, Singapore
- Tan Tock Seng Hospital, Singapore (M.K.-S.L., H.H.H.)
| | - Hee Hwa Ho
- Tan Tock Seng Hospital, Singapore (M.K.-S.L., H.H.H.)
| | - Yong-Gui Gao
- School of Biological Sciences (A.V., K.P., G.J., S.C.N., Y.-G.G., S.K.S.), Nanyang Technological University, Singapore
| | - Kah Leong Lim
- Lee Kong Chian School of Medicine (M.K.-S.L., K.L.L.), Nanyang Technological University, Singapore
| | - A Mark Richards
- Department of Cardiology, National University Heart Centre, Singapore (A.M.R.)
- Department of Cardiology, University of Otago, Christchurch, New Zealand (A.M.R.)
| | | | - Christopher P Chen
- Memory Aging and Cognition Centre, Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore (C.P.C.)
| | - Raj N Kalaria
- Translational and Clinical Research Institute, Campus for Ageing and Vitality, Newcastle University, Newcastle upon Tyne, United Kingdom (R.N.K.)
| | - Jian Liu
- Department of Health Sciences, Faculty of Applied Health Sciences, Brock University, St. Catharines, ON, Canada (S.C.N., J.L., D.D.O., S.K.S.)
| | - Deborah D O'Leary
- Department of Health Sciences, Faculty of Applied Health Sciences, Brock University, St. Catharines, ON, Canada (S.C.N., J.L., D.D.O., S.K.S.)
| | - Neil E McCarthy
- Centre for Immunobiology, The Blizard Institute, Bart's and The London School of Medicine and Dentistry, Queen Mary University of London, United Kingdom (N.E.M.)
| | - Siu Kwan Sze
- School of Biological Sciences (A.V., K.P., G.J., S.C.N., Y.-G.G., S.K.S.), Nanyang Technological University, Singapore
- Department of Health Sciences, Faculty of Applied Health Sciences, Brock University, St. Catharines, ON, Canada (S.C.N., J.L., D.D.O., S.K.S.)
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Blaustein MP, Gottlieb SS, Hamlyn JM, Leenen FHH. Whither digitalis? What we can still learn from cardiotonic steroids about heart failure and hypertension. Am J Physiol Heart Circ Physiol 2022; 323:H1281-H1295. [PMID: 36367691 DOI: 10.1152/ajpheart.00362.2022] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Cloning of the "Na+ pump" (Na+,K+-ATPase or NKA) and identification of a circulating ligand, endogenous ouabain (EO), a cardiotonic steroid (CTS), triggered seminal discoveries regarding EO and its NKA receptor in cardiovascular function and the pathophysiology of heart failure (HF) and hypertension. Cardiotonic digitalis preparations were a preferred treatment for HF for two centuries, but digoxin was only marginally effective in a large clinical trial (1997). This led to diminished digoxin use. Missing from the trial, however, was any consideration that endogenous CTS might influence digitalis' efficacy. Digoxin, at therapeutic concentrations, acutely inhibits NKA but, remarkably, antagonizes ouabain's action. Prolonged treatment with ouabain, but not digoxin, causes hypertension in rodents; in this model, digoxin lowers blood pressure (BP). Furthermore, NKA-bound ouabain and digoxin modulate different protein kinase signaling pathways and have disparate long-term cardiovascular effects. Reports of "brain ouabain" led to the elucidation of a new, slow neuromodulatory pathway in the brain; locally generated EO and the α2 NKA isoform help regulate sympathetic drive to the heart and vasculature. The roles of EO and α2 NKA have been studied by EO assay, ouabain-resistant mutation of α2 NKA, and immunoneutralization of EO with ouabain-binding Fab fragments. The NKA α2 CTS binding site and its endogenous ligand are required for BP elevation in many common hypertension models and full expression of cardiac remodeling and dysfunction following pressure overload or myocardial infarction. Understanding how endogenous CTS impact hypertension and HF pathophysiology and therapy should foster reconsideration of digoxin's therapeutic utility.
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Affiliation(s)
- Mordecai P Blaustein
- Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland.,Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland
| | - Stephen S Gottlieb
- Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland
| | - John M Hamlyn
- Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland
| | - Frans H H Leenen
- Brain and Heart Research Group, University of Ottawa Heart Institute, Ottawa, Ontario, Canada
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Ehret E, Hummler E. Lessons learned about epithelial sodium channels from transgenic mouse models. Curr Opin Nephrol Hypertens 2022; 31:493-501. [PMID: 35894285 PMCID: PMC10022670 DOI: 10.1097/mnh.0000000000000821] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE OF REVIEW This review provides an up-to-date understanding about the regulation of epithelial sodium channel (ENaC) expression and function. In particular, we will focus on its implication in renal Na+ and K+ handling and control of blood pressure using transgenic animal models. RECENT FINDINGS In kidney, the highly amiloride-sensitive ENaC maintains whole body Na+ homeostasis by modulating Na+ transport via epithelia. This classical role is mostly confirmed using genetically engineered animal models. Recently identified key signaling pathways that regulate ENaC expression and function unveiled some nonclassical and unexpected channel regulatory processes. If aberrant, these dysregulated mechanisms may also result in the development of salt-dependent hypertension.The purpose of this review is to highlight the most recent findings in renal ENaC regulation and function, in considering data obtained from animal models. SUMMARY Increased ENaC-mediated Na+ transport is a prerequisite for salt-dependent forms of hypertension. To treat salt-sensitive hypertension it is crucial to fully understand the function and regulation of ENaC.
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Affiliation(s)
- Elodie Ehret
- Department of Biomedical Sciences, Faculty of Biology and Medicine, University of Lausanne, Lausanne
| | - Edith Hummler
- Department of Biomedical Sciences, Faculty of Biology and Medicine, University of Lausanne, Lausanne
- National Center of Competence in Research, Kidney.CH, Zurich, Switzerland
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The NEDD4 ubiquitin E3 ligase: a snapshot view of its functional activity and regulation. Biochem Soc Trans 2022; 50:473-485. [PMID: 35129615 DOI: 10.1042/bst20210731] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Revised: 01/18/2022] [Accepted: 01/18/2022] [Indexed: 11/17/2022]
Abstract
Due to its fundamental role in all eukaryotic cells, a deeper understanding of the molecular mechanisms underlying ubiquitination is of central importance. Being responsible for chain specificity and substrate recognition, E3 ligases are the selective elements of the ubiquitination process. In this review, we discuss different cellular pathways regulated by one of the first identified E3 ligase, NEDD4, focusing on its pathophysiological role, its known targets and modulators. In addition, we highlight small molecule inhibitors that act on NEDD4 and discuss new strategies to effectively target this E3 enzyme.
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10
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Zhang J, Yuan HK, Chen S, Zhang ZR. Detrimental or beneficial: Role of endothelial ENaC in vascular function. J Cell Physiol 2021; 237:29-48. [PMID: 34279047 DOI: 10.1002/jcp.30505] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 06/29/2021] [Accepted: 07/01/2021] [Indexed: 12/19/2022]
Abstract
In the past, it was believed that the expression of the epithelial sodium channel (ENaC) was restricted to epithelial tissues, such as the distal nephron, airway, sweat glands, and colon, where it is critical for sodium homeostasis. Over the past two decades, this paradigm has shifted due to the finding that ENaC is also expressed in various nonepithelial tissues, notably in vascular endothelial cells. In this review, the recent findings of the expression, regulation, and function of the endothelial ENaC (EnNaC) are discussed. The expression of EnNaC subunits is reported in a variety of endothelial cell lines and vasculatures, but this is controversial across different species and vessels and is not a universal finding in all vascular beds. The expression density of EnNaC is very faint compared to ENaC in the epithelium. To date, little is known about the regulatory mechanism of EnNaC. Through it can be regulated by aldosterone, the detailed downstream signaling remains elusive. EnNaC responds to increased extracellular sodium with the feedforward activation mechanism, which is quite different from the Na+ self-inhibition mechanism of ENaC. Functionally, EnNaC was shown to be a determinant of cellular mechanics and vascular tone as it can sense shear stress, and its activation or insertion into plasma membrane causes endothelial stiffness and reduced nitric oxide production. However, in some blood vessels, EnNaC is essential for maintaining the integrity of endothelial barrier function. In this context, we discuss the possible reasons for the distinct role of EnNaC in vasculatures.
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Affiliation(s)
- Jun Zhang
- School of Biomedical Sciences and Li Ka Shing Institute of Health Science, The Chinese University of Hong Kong, Hong Kong, China
| | - Hui-Kai Yuan
- Department of General Surgery, The First Affiliated Hospital of Harbin Medical University, Harbin, China
| | - Shuo Chen
- Department of Biopharmaceutical Sciences, School of Pharmacy, Harbin Medical University (Daqing), Daqing, China
| | - Zhi-Ren Zhang
- Departments of Pharmacy and Cardiology, Harbin Medical University Cancer Hospital, Institute of Metabolic Disease, Heilongjiang Academy of Medical Science, Heilongjiang Key Laboratory for Metabolic Disorder & Cancer Related Cardiovascular Diseases, NHC Key Laboratory of Cell Transplantation, Harbin Medical University & Key Laboratories of Education Ministry for Myocardial Ischemia Mechanism and Treatment, Harbin, China
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11
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de Souza JA, Becker LK, Batista MAC, de Assis Braga DC, Gomes PM, Alzamora AC, Vieira MAR, de Lima WG, Andrade MGC, de Lima Sanches B, Totou NL, de Assis Dias Martins Júnior F, de Oliveira LB, Antunes VR, Cardoso LM. Swimming training improves cardiovascular autonomic dysfunctions and prevents renal damage in rats fed a high-sodium diet from weaning. Exp Physiol 2020; 106:412-426. [PMID: 33347659 DOI: 10.1113/ep088892] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Accepted: 12/03/2020] [Indexed: 01/03/2023]
Abstract
NEW FINDINGS What is the central question of this study? How does swimming exercise training impact hydro-electrolytic balance, renal function, sympathetic contribution to resting blood pressure and cerebrospinal fluid (CSF) [Na+ ] in rats fed a high-sodium diet from weaning? What is the main finding and its importance? An exercise-dependent reduction in blood pressure was associated with decreased CSF [Na+ ], sympathetically driven vasomotor tonus and renal fibrosis indicating that the anti-hypertensive effects of swimming training in rats fed a high-sodium diet might involve neurogenic mechanisms regulated by sodium levels in the CSF rather than changes in blood volume. ABSTRACT High sodium intake is an important factor associated with hypertension. High-sodium intake with exercise training can modify homeostatic hydro-electrolytic balance, but the effects of this association are mostly unknown. In this study, we sought to investigate the effects of swimming training (ST) on cerebrospinal fluid (CSF) Na+ concentration, sympathetic drive, blood pressure (BP) and renal function of rats fed a 0.9% Na+ (equivalent to 2% NaCl) diet with free access to water for 22 weeks after weaning. Male Wistar rats were assigned to two cohorts: (1) fed standard diet (SD) and (2) fed high-sodium (HS) diet. Each cohort was further divided into trained and sedentary groups. ST normalised BP levels of HS rats as well as the higher sympathetically related pressor activity assessed by pharmacological blockade of ganglionic transmission (hexamethonium). ST preserved the renal function and attenuated the glomerular shrinkage elicited by HS. No change in blood volume was found among the groups. CSF [Na+ ] levels were higher in sedentary HS rats but were reduced by ST. Our findings showed that ST effectively normalised BP of HS rats, independent of its effects on hydro-electrolytic balance, which might involve neurogenic mechanisms regulated by Na+ levels in the CSF as well as renal protection.
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Affiliation(s)
| | - Lenice Kappes Becker
- Physical Education School at the Federal University of Ouro Preto, Ouro Preto, MG, Brazil
| | | | | | - Paula Magalhães Gomes
- Deptartment of Physiology and Biophysics, ICB; University of São Paulo, São Paulo, SP, Brazil
| | - Andréia Carvalho Alzamora
- Department of Biological Sciences, ICEB at the Federal University of Ouro Preto, Ouro Preto, MG, Brazil
| | | | - Wanderson Geraldo de Lima
- Department of Biological Sciences, ICEB at the Federal University of Ouro Preto, Ouro Preto, MG, Brazil
| | | | - Bruno de Lima Sanches
- Department of Physiology and Biophysics, ICB; Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
| | - Nádia Lúcia Totou
- Department of Biological Sciences, ICEB at the Federal University of Ouro Preto, Ouro Preto, MG, Brazil
| | | | | | - Vagner Roberto Antunes
- Deptartment of Physiology and Biophysics, ICB; University of São Paulo, São Paulo, SP, Brazil
| | - Leonardo Máximo Cardoso
- Department of Biological Sciences, ICEB at the Federal University of Ouro Preto, Ouro Preto, MG, Brazil
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12
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Salt-dependent hypertension and inflammation: targeting the gut-brain axis and the immune system with Brazilian green propolis. Inflammopharmacology 2020; 28:1163-1182. [PMID: 32785827 PMCID: PMC8826348 DOI: 10.1007/s10787-020-00742-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Accepted: 07/30/2020] [Indexed: 01/22/2023]
Abstract
Systemic arterial hypertension (SAH) is a major health problem around the world and its development has been associated with exceeding salt consumption by the modern society. The mechanisms by which salt consumption increase blood pressure (BP) involve several homeostatic systems but many details have not yet been fully elucidated. Evidences accumulated over the last 60 decades raised the involvement of the immune system in the hypertension development and opened a range of possibilities for new therapeutic targets. Green propolis is a promising natural product with potent anti-inflammatory properties acting on specific targets, most of them participating in the gut-brain axis of the sodium-dependent hypertension. New anti-hypertensive products reinforce the therapeutic arsenal improving the corollary of choices, especially in those cases where patients are resistant or refractory to conventional therapy. This review sought to bring the newest advances in the field articulating evidences that show a cross-talking between inflammation and the central mechanisms involved with the sodium-dependent hypertension as well as the stablished actions of green propolis and some of its biologically active compounds on the immune cells and cytokines that would be involved with its anti-hypertensive properties.
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13
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Wang S, Liu J, Cai H, Liu K, He Y, Liu S, Guo Y, Guo L. High salt diet elevates the mean arterial pressure of SLC14α1 gene depletion mice. Life Sci 2020; 254:117751. [PMID: 32387413 DOI: 10.1016/j.lfs.2020.117751] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2020] [Revised: 04/30/2020] [Accepted: 05/02/2020] [Indexed: 01/01/2023]
Abstract
AIMS Urea transporter B (UTB) is encoded by the SLC14α1 gene, and exerts its activity in the choroid plexus (CP) by regulating [Na+] in the cerebrospinal fluid (CSF) and maintaining normal blood pressure in mice fed on high salt diet. The aim of this study is to investigate the effect of high salt diet on the mean arterial pressure (MAP) in SLC14α1 depletion mice and its possible molecular mechanism. MAIN METHODS Adult male mice were divided into four groups: 1) UTB+/+(wild type) mice + normal salt diet (0.3% NaCl, NS); 2) UTB+/+ mice + high salt diet (8% NaCl, HS); 3) UTB-/- (SLC14α1 knockout) mice + NS; 4) UTB-/- mice + HS, each group consisted of 6 mice. The MAP of mice was measured by non-invasive detection method after HS diet for 4 weeks, followed by euthanization for brain and blood collection. KEY FINDINGS HS significantly elevated the MAP and CSF [Na+] in UTB-/- mice in comparison with wild type mice; however, NS didn't alter the MAP and CSF [Na+] in either wild type mice or UTB-/- mice. HS also induced the expression of ENaC-α and α1-Na+-K+-ATPase in UTB-/- mice as confirmed by RT-PCR and Western blot. SIGNIFICANCE These results suggest that the depletion of SLC14α1 gene in mice may contribute to the HS-induced abnormality of sodium transportation in the CSF, and lead to the elevation of MAP, which eventually promote the development of salt-sensitive hypertension.
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Affiliation(s)
- Song Wang
- Nursing School of Jilin University, Changchun, Jilin 130021, China; Liao Cheng People's Hospital, Liaocheng, Shandong 252000, China
| | - Jinshu Liu
- Nursing School of Jilin University, Changchun, Jilin 130021, China
| | - Hongwei Cai
- Nursing School of Jilin University, Changchun, Jilin 130021, China
| | - Keyuan Liu
- Department of Pathophysiology, Basic College of Medicine, Jilin University, Changchun, Jilin 130021, China
| | - Yayu He
- Nursing School of Jilin University, Changchun, Jilin 130021, China
| | - Shuxiang Liu
- Nursing School of Jilin University, Changchun, Jilin 130021, China
| | - Yingze Guo
- Nursing School of Jilin University, Changchun, Jilin 130021, China
| | - Lirong Guo
- Nursing School of Jilin University, Changchun, Jilin 130021, China.
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14
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Ghaffari H, Grant SC, Petzold LR, Harrington MG. Regulation of CSF and Brain Tissue Sodium Levels by the Blood-CSF and Blood-Brain Barriers During Migraine. Front Comput Neurosci 2020; 14:4. [PMID: 32116618 PMCID: PMC7010722 DOI: 10.3389/fncom.2020.00004] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Accepted: 01/10/2020] [Indexed: 11/13/2022] Open
Abstract
Cerebrospinal fluid (CSF) and brain tissue sodium levels increase during migraine. However, little is known regarding the underlying mechanisms of sodium homeostasis disturbance in the brain during the onset and propagation of migraine. Exploring the cause of sodium dysregulation in the brain is important, since correction of the altered sodium homeostasis could potentially treat migraine. Under the hypothesis that disturbances in sodium transport mechanisms at the blood-CSF barrier (BCSFB) and/or the blood-brain barrier (BBB) are the underlying cause of the elevated CSF and brain tissue sodium levels during migraines, we developed a mechanistic, differential equation model of a rat's brain to compare the significance of the BCSFB and the BBB in controlling CSF and brain tissue sodium levels. The model includes the ventricular system, subarachnoid space, brain tissue and blood. Sodium transport from blood to CSF across the BCSFB, and from blood to brain tissue across the BBB were modeled by influx permeability coefficients PBCSFB and PBBB, respectively, while sodium movement from CSF into blood across the BCSFB, and from brain tissue to blood across the BBB were modeled by efflux permeability coefficients PBCSFB′ and PBBB′, respectively. We then performed a global sensitivity analysis to investigate the sensitivity of the ventricular CSF, subarachnoid CSF and brain tissue sodium concentrations to pathophysiological variations in PBCSFB, PBBB, PBCSFB′ and PBBB′. Our results show that the ventricular CSF sodium concentration is highly influenced by perturbations of PBCSFB, and to a much lesser extent by perturbations of PBCSFB′. Brain tissue and subarachnoid CSF sodium concentrations are more sensitive to pathophysiological variations of PBBB and PBBB′ than variations of PBCSFB and PBCSFB′ within 30 min of the onset of the perturbations. However, PBCSFB is the most sensitive model parameter, followed by PBBB and PBBB′, in controlling brain tissue and subarachnoid CSF sodium levels within 3 h of the perturbation onset.
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Affiliation(s)
- Hamed Ghaffari
- Department of Mechanical Engineering, University of California, Santa Barbara, Santa Barbara, CA, United States
| | - Samuel C Grant
- Department of Chemical and Biomedical Engineering, FAMU-FSU College of Engineering, Tallahassee, FL, United States
| | - Linda R Petzold
- Department of Mechanical Engineering, University of California, Santa Barbara, Santa Barbara, CA, United States
| | - Michael G Harrington
- Neuroscience, Huntington Medical Research Institutes, Pasadena, CA, United States
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15
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Souza LAC, Trebak F, Kumar V, Satou R, Kehoe PG, Yang W, Wharton W, Feng Earley Y. Elevated cerebrospinal fluid sodium in hypertensive human subjects with a family history of Alzheimer's disease. Physiol Genomics 2020; 52:133-142. [PMID: 31961762 DOI: 10.1152/physiolgenomics.00093.2019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
High salt (sodium) intake leads to the development of hypertension despite the fact that plasma sodium concentration ([Na+]) is usually normal in hypertensive human patients. Increased cerebrospinal fluid (CSF) sodium contributes to elevated sympathetic activity and high blood pressure (BP) in rodent models of hypertension. However, whether there is an increased accumulation of sodium in the CSF of humans with chronic hypertension is not well defined. Here, we investigated CSF [Na+] from hypertensive and normotensive human subjects with family histories of Alzheimer's disease in samples collected in a clinical trial, as spinal tap is not a routine clinical procedure for hypertensive patients. The [Na+] and osmolality in plasma and CSF were measured by flame photometry. Daytime ambulatory BP was monitored while individuals were awake. Participants were deidentified and data were analyzed in conjunction with a retrospective analysis of patient history and diagnosis. We found that CSF [Na+] was significantly higher in participants with high BP compared with normotensive participants; there was no difference in plasma [Na+], or plasma and CSF osmolality between groups. Subsequent multiple linear regression analyses controlling for age, sex, race, and body mass index revealed a significant positive correlation between CSF [Na+] and BP but showed no correlation between plasma [Na+] and BP. In sum, CSF [Na+] was higher in chronic hypertensive individuals and may play a key role in the pathogenesis of human hypertension. Collectively, our findings provide evidence for the clinical significance of CSF [Na+] in chronic hypertension in humans.
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Affiliation(s)
- Lucas A C Souza
- Departments of Pharmacology and Physiology & Cell Biology, University of Nevada, Reno, School of Medicine, Reno, Nevada.,Center for Molecular and Cellular Signaling in the Cardiovascular System, University of Nevada, Reno, Reno, Nevada
| | - Fatima Trebak
- Departments of Pharmacology and Physiology & Cell Biology, University of Nevada, Reno, School of Medicine, Reno, Nevada.,Center for Molecular and Cellular Signaling in the Cardiovascular System, University of Nevada, Reno, Reno, Nevada
| | - Veena Kumar
- Department of Neurology, Emory University School of Nursing, Atlanta, Georgia
| | - Ryousuke Satou
- Department of Physiology, Tulane University School of Medicine, New Orleans, Louisiana
| | - Patrick G Kehoe
- Institute of Clinical Neurosciences, University of Bristol, Bristol, United Kingdom
| | - Wei Yang
- University of Nevada, Reno, School of Community Health Sciences, Reno, Nevada
| | - Whitney Wharton
- Department of Neurology, Emory University School of Nursing, Atlanta, Georgia
| | - Yumei Feng Earley
- Departments of Pharmacology and Physiology & Cell Biology, University of Nevada, Reno, School of Medicine, Reno, Nevada.,Center for Molecular and Cellular Signaling in the Cardiovascular System, University of Nevada, Reno, Reno, Nevada
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16
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Bukhari AAS, Zhang X, Li M, Zhao A, Dong H, Liang X. Cofilin participates in regulating alpha-epithelial sodium channel by interaction with 14-3-3 isoforms. J Biomed Res 2020; 34:351-360. [PMID: 32981895 PMCID: PMC7540242 DOI: 10.7555/jbr.34.20190155] [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] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Renal epithelial sodium channel (ENaC) plays a crucial role in maintaining homeostasis and sodium absorption. While insulin participates in controlling sodium transport across the renal epithelium, the underlying molecular mechanism remain unclear. In this study, we found that insulin increased the expression and function of alpha-epithelial sodium channel (α-ENaC) as well as phosphorylation of cofilin, a family of actin-binding proteins which disassembles actin filaments, in mouse cortical collecting duct (mpkCCDc14) cells. The wild-type (WT) cofilin and its constitutively phosphorylated form (S3D), but not its constitutively non-phosphorylable form (S3A), contributed to the elevated expression on α-ENaC. Overexpression of 14-3-3ε, β, or γ increased the expression of α-ENaC and cofilin phosphorylation, which was blunted by knockdown of 14-3-3ε, β, or γ. Moreover, it was found that insulin increased the interaction between cofilin and 14-3-3 isoforms, which indicated relevance of 14-3-3 isoforms with cofilin. Furthermore, LIMK1/SSH1 pathway was involved in regulation of cofilin and α-ENaC expression by insulin. The results from this work indicate that cofilin participates in the regulation of α-ENaC by interaction with 14-3-3 isoforms.
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Affiliation(s)
| | | | | | | | | | - Xiubin Liang
- Department of Pathophysiology;Department of Nephrology, the Affiliated Sir Run Run Hospital of Nanjing Medical University, Nanjing, Jiangsu 211166, China
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17
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Dietary sodium modulates nephropathy in Nedd4-2-deficient mice. Cell Death Differ 2019; 27:1832-1843. [PMID: 31802037 PMCID: PMC7244563 DOI: 10.1038/s41418-019-0468-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Revised: 11/20/2019] [Accepted: 11/21/2019] [Indexed: 12/05/2022] Open
Abstract
Salt homeostasis is maintained by tight control of Na+ filtration and reabsorption. In the distal part of the nephron the ubiquitin protein ligase Nedd4-2 regulates membrane abundance and thus activity of the epithelial Na+ channel (ENaC), which is rate-limiting for Na+ reabsorption. Nedd4-2 deficiency in mouse results in elevated ENaC and nephropathy, however the contribution of dietary salt to this has not been characterized. In this study we show that high dietary Na+ exacerbated kidney injury in Nedd4-2-deficient mice, significantly perturbing normal postnatal nephrogenesis and resulting in multifocal areas of renal dysplasia, increased markers of kidney injury and a decline in renal function. In control mice, high dietary Na+ resulted in reduced levels of ENaC. However, Nedd4-2-deficient kidneys maintained elevated ENaC even after high dietary Na+, suggesting that the inability to efficiently downregulate ENaC is responsible for the salt-sensitivity of disease. Importantly, low dietary Na+ significantly ameliorated nephropathy in Nedd4-2-deficient mice. Our results demonstrate that due to dysregulation of ENaC, kidney injury in Nedd4-2-deficient mice is sensitive to dietary Na+, which may have implications in the management of disease in patients with kidney disease.
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18
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Li Q, Fung E. Multifaceted Functions of Epithelial Na + Channel in Modulating Blood Pressure. Hypertension 2019; 73:273-281. [PMID: 30580685 DOI: 10.1161/hypertensionaha.118.12330] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Qi Li
- From the Division of Cardiology, Department of Medicine and Therapeutics, Faculty of Medicine, The Chinese University of Hong Kong (Q.L., E.F.).,Laboratory for Heart Failure and Circulation Research, Li Ka Shing Institute of Health Sciences, Prince of Wales Hospital, Hong Kong SAR (Q.L., E.F.)
| | - Erik Fung
- From the Division of Cardiology, Department of Medicine and Therapeutics, Faculty of Medicine, The Chinese University of Hong Kong (Q.L., E.F.).,Gerald Choa Cardiac Research Centre, Faculty of Medicine, The Chinese University of Hong Kong (E.F.).,Lui Che Woo Institute of Innovative Medicine, Faculty of Medicine, The Chinese University of Hong Kong (E.F.).,Laboratory for Heart Failure and Circulation Research, Li Ka Shing Institute of Health Sciences, Prince of Wales Hospital, Hong Kong SAR (Q.L., E.F.)
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19
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Tuday E, Nomura Y, Ruhela D, Nakano M, Fu X, Shah A, Roman B, Yamaguchi A, An SS, Steenbergen C, Baraban JM, Berkowitz DE, Das S. Deletion of the microRNA-degrading nuclease, translin/trax, prevents pathogenic vascular stiffness. Am J Physiol Heart Circ Physiol 2019; 317:H1116-H1124. [PMID: 31625778 DOI: 10.1152/ajpheart.00153.2019] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Vascular stiffness plays a key role in the pathogenesis of hypertension. Recent studies indicate that the age-associated reduction in miR-181b levels in vascular smooth muscle cells (VSMCs) contributes to increased vascular stiffness. As these findings suggest that inhibiting degradation of miR-181b might prevent vascular stiffening, we have assessed whether the microRNA-degrading translin/trax (TN/TX) complex mediates degradation of miR-181b in the aorta.We found that TN-/- mice display elevated levels of miR-181b expression in the aorta. Therefore, we tested whether TN deletion prevents vascular stiffening in a mouse model of hypertension, induced by chronic high-salt intake (4%NaCl in drinking water for 3 wk; HSW). TN-/- mice subjected to HSW stress do not show increased vascular stiffness, as monitored by pulse wave velocity and tensile testing. The protective effect of TN deletion in the HSW paradigm appears to be mediated by its ability to increase miR-181b in the aorta since HSW decreases levels of miR-181b in WT mice, but not in TN KO mice. We demonstrate for the first time that interfering with microRNA degradation can have a beneficial impact on the vascular system and identify the microRNA-degrading TN/TX RNase complex as a potential therapeutic target in combatting vascular stiffness.NEW & NOTEWORTHY While the biogenesis and mechanism of action of mature microRNA are well understood, much less is known about the regulation of microRNA via degradation. Recent studies have identified the protein complex, translin(TN)/trax(TX), as a microRNA-degrading enzyme. Here, we demonstrate that TN/TX is expressed in vascular smooth muscle cells. Additionally, deletion of the TN/TX complex selectively increases aortic miR-181b and prevents increased vascular stiffness caused by ingestion of high-salt water. To our knowledge, this is first report describing the role of a microRNA RNAse in cardiovascular biology or pathobiology.
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Affiliation(s)
- Eric Tuday
- Division of Cardiology, Department of Medicine, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Yohei Nomura
- Division of Cardiac Surgery, Department of Surgery, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Deepa Ruhela
- Department of Pathology, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Mitsunori Nakano
- Division of Cardiac Surgery, Department of Surgery, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Xiuping Fu
- Solomon H. Snyder Department of Neuroscience and Department of Psychiatry and Behavioral Sciences, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Aparna Shah
- Solomon H. Snyder Department of Neuroscience and Department of Psychiatry and Behavioral Sciences, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Barbara Roman
- Department of Pathology, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Atsushi Yamaguchi
- Department of Cardiovascular Surgery, Saitama Medical Center, Jichi Medical University, Saitama, Japan
| | - Steven S An
- Department of Environmental Health and Engineering, Jichi Medical University, Saitama, Japan.,Department of Biochemistry and Molecular Biology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Charles Steenbergen
- Department of Pathology, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Jay M Baraban
- Solomon H. Snyder Department of Neuroscience and Department of Psychiatry and Behavioral Sciences, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Dan E Berkowitz
- Department of Anesthesiology and Perioperative Medicine, University of Alabama, Birmingham, Alabama
| | - Samarjit Das
- Department of Pathology, Johns Hopkins School of Medicine, Baltimore, Maryland.,Department of Anesthesiology and Critical Care Medicine, Johns Hopkins School of Medicine, Baltimore, Maryland
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20
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Lashhab R, Ullah AS, Cordat E. Renal collecting duct physiology and pathophysiology. Biochem Cell Biol 2019; 97:234-242. [DOI: 10.1139/bcb-2018-0192] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Affiliation(s)
- Rawad Lashhab
- Department of Physiology and Membrane Protein and Disease Research Group, University of Alberta, Edmonton, AB T6G 2H7, Canada
- Department of Physiology and Membrane Protein and Disease Research Group, University of Alberta, Edmonton, AB T6G 2H7, Canada
| | - A.K.M. Shahid Ullah
- Department of Physiology and Membrane Protein and Disease Research Group, University of Alberta, Edmonton, AB T6G 2H7, Canada
- Department of Physiology and Membrane Protein and Disease Research Group, University of Alberta, Edmonton, AB T6G 2H7, Canada
| | - Emmanuelle Cordat
- Department of Physiology and Membrane Protein and Disease Research Group, University of Alberta, Edmonton, AB T6G 2H7, Canada
- Department of Physiology and Membrane Protein and Disease Research Group, University of Alberta, Edmonton, AB T6G 2H7, Canada
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21
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Nomura K, Hiyama TY, Sakuta H, Matsuda T, Lin CH, Kobayashi K, Kobayashi K, Kuwaki T, Takahashi K, Matsui S, Noda M. [Na +] Increases in Body Fluids Sensed by Central Na x Induce Sympathetically Mediated Blood Pressure Elevations via H +-Dependent Activation of ASIC1a. Neuron 2018; 101:60-75.e6. [PMID: 30503172 DOI: 10.1016/j.neuron.2018.11.017] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Revised: 10/08/2018] [Accepted: 11/08/2018] [Indexed: 02/07/2023]
Abstract
Increases in sodium concentrations ([Na+]) in body fluids elevate blood pressure (BP) by enhancing sympathetic nerve activity (SNA). However, the mechanisms by which information on increased [Na+] is translated to SNA have not yet been elucidated. We herein reveal that sympathetic activation leading to BP increases is not induced by mandatory high salt intakes or the intraperitoneal/intracerebroventricular infusions of hypertonic NaCl solutions in Nax-knockout mice in contrast to wild-type mice. We identify Nax channels expressed in specific glial cells in the organum vasculosum lamina terminalis (OVLT) as the sensors detecting increases in [Na+] in body fluids and show that OVLT neurons projecting to the paraventricular nucleus (PVN) are activated via acid-sensing ion channel 1a (ASIC1a) by H+ ions exported from Nax-positive glial cells. The present results provide an insight into the neurogenic mechanisms responsible for salt-induced BP elevations.
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Affiliation(s)
- Kengo Nomura
- Division of Molecular Neurobiology, National Institute for Basic Biology, Okazaki, Aichi 444-8787, Japan
| | - Takeshi Y Hiyama
- Division of Molecular Neurobiology, National Institute for Basic Biology, Okazaki, Aichi 444-8787, Japan; School of Life Science, SOKENDAI (The Graduate University for Advanced Studies), Okazaki, Aichi 444-8787, Japan
| | - Hiraki Sakuta
- Division of Molecular Neurobiology, National Institute for Basic Biology, Okazaki, Aichi 444-8787, Japan; School of Life Science, SOKENDAI (The Graduate University for Advanced Studies), Okazaki, Aichi 444-8787, Japan
| | - Takashi Matsuda
- Division of Molecular Neurobiology, National Institute for Basic Biology, Okazaki, Aichi 444-8787, Japan
| | - Chia-Hao Lin
- Division of Molecular Neurobiology, National Institute for Basic Biology, Okazaki, Aichi 444-8787, Japan
| | - Kenta Kobayashi
- Section of Viral Vector Development, National Institute for Physiological Sciences, Okazaki, Aichi 444-8585, Japan
| | - Kazuto Kobayashi
- Department of Molecular Genetics, Institute of Biomedical Sciences, Fukushima Medical University School of Medicine, Fukushima 960-1295, Japan
| | - Tomoyuki Kuwaki
- Department of Physiology, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima 890-8544, Japan
| | - Kunihiko Takahashi
- Department of Biostatistics, Nagoya University Graduate School of Medicine, Nagoya, Aichi 466-8550, Japan
| | - Shigeyuki Matsui
- Department of Biostatistics, Nagoya University Graduate School of Medicine, Nagoya, Aichi 466-8550, Japan
| | - Masaharu Noda
- Division of Molecular Neurobiology, National Institute for Basic Biology, Okazaki, Aichi 444-8787, Japan; School of Life Science, SOKENDAI (The Graduate University for Advanced Studies), Okazaki, Aichi 444-8787, Japan; Research Center for Cell Biology, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Kanagawa 226-8503, Japan.
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22
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Kurtz TW, DiCarlo SE, Pravenec M, Morris RC. Changing views on the common physiologic abnormality that mediates salt sensitivity and initiation of salt-induced hypertension: Japanese research underpinning the vasodysfunction theory of salt sensitivity. Hypertens Res 2018; 42:6-18. [DOI: 10.1038/s41440-018-0122-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Revised: 07/26/2018] [Accepted: 07/27/2018] [Indexed: 12/24/2022]
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23
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Feetham CH, O'Brien F, Barrett-Jolley R. Ion Channels in the Paraventricular Hypothalamic Nucleus (PVN); Emerging Diversity and Functional Roles. Front Physiol 2018; 9:760. [PMID: 30034342 PMCID: PMC6043726 DOI: 10.3389/fphys.2018.00760] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2018] [Accepted: 05/30/2018] [Indexed: 12/11/2022] Open
Abstract
The paraventricular nucleus of the hypothalamus (PVN) is critical for the regulation of homeostatic function. Although also important for endocrine regulation, it has been referred to as the "autonomic master controller." The emerging consensus is that the PVN is a multifunctional nucleus, with autonomic roles including (but not limited to) coordination of cardiovascular, thermoregulatory, metabolic, circadian and stress responses. However, the cellular mechanisms underlying these multifunctional roles remain poorly understood. Neurones from the PVN project to and can alter the function of sympathetic control regions in the medulla and spinal cord. Dysfunction of sympathetic pre-autonomic neurones (typically hyperactivity) is linked to several diseases including hypertension and heart failure and targeting this region with specific pharmacological or biological agents is a promising area of medical research. However, to facilitate future medical exploitation of the PVN, more detailed models of its neuronal control are required; populated by a greater compliment of constituent ion channels. Whilst the cytoarchitecture, projections and neurotransmitters present in the PVN are reasonably well documented, there have been fewer studies on the expression and interplay of ion channels. In this review we bring together an up to date analysis of PVN ion channel studies and discuss how these channels may interact to control, in particular, the activity of the sympathetic system.
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Affiliation(s)
- Claire H Feetham
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Fiona O'Brien
- Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, United Kingdom
| | - Richard Barrett-Jolley
- Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, United Kingdom
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Manning JA, Kumar S. Physiological Functions of Nedd4-2: Lessons from Knockout Mouse Models. Trends Biochem Sci 2018; 43:635-647. [PMID: 30056838 DOI: 10.1016/j.tibs.2018.06.004] [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] [Received: 04/05/2018] [Revised: 05/11/2018] [Accepted: 06/04/2018] [Indexed: 01/10/2023]
Abstract
Protein modification by ubiquitination plays a key evolutionarily conserved role in regulating membrane proteins. Nedd4-2, a ubiquitin ligase, targets membrane proteins such as ion channels and transporters for ubiquitination. This Nedd4-2-mediated ubiquitination provides a crucial step in controlling the membrane availability of these proteins, thus affecting their signaling and physiological outcomes. In one well-studied example, Nedd4-2 fine-tunes the physiological function of the epithelial sodium channel (ENaC), thus modulating Na+ reabsorption by epithelia to maintain whole-body Na+ homeostasis. This review summarizes the key signaling pathways regulated by Nedd4-2 and the possible implications of such regulation in various pathologies.
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Affiliation(s)
- Jantina A Manning
- Centre for Cancer Biology, University of South Australia and SA Pathology, GPO Box 2471, Adelaide, SA 5001, Australia
| | - Sharad Kumar
- Centre for Cancer Biology, University of South Australia and SA Pathology, GPO Box 2471, Adelaide, SA 5001, Australia.
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25
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Petrik D, Myoga MH, Grade S, Gerkau NJ, Pusch M, Rose CR, Grothe B, Götz M. Epithelial Sodium Channel Regulates Adult Neural Stem Cell Proliferation in a Flow-Dependent Manner. Cell Stem Cell 2018; 22:865-878.e8. [DOI: 10.1016/j.stem.2018.04.016] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Revised: 02/16/2018] [Accepted: 04/17/2018] [Indexed: 12/22/2022]
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26
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Abstract
Liddle syndrome is an inherited form of low-renin hypertension, transmitted with an autosomal dominant pattern. The molecular basis of Liddle syndrome resides in germline mutations of the SCNN1A, SCNN1B and SCNN1G genes, encoding the α, β, and γ-subunits of the epithelial Na+ channel (ENaC), respectively. To date, 31 different causative mutations have been reported in 72 families from four continents. The majority of the substitutions cause an increased expression of the channel at the distal nephron apical membrane, with subsequent enhanced renal sodium reabsorption. The most common clinical presentation of the disease is early onset hypertension, hypokalemia, metabolic alkalosis, suppressed plasma renin activity and low plasma aldosterone. Consequently, treatment of Liddle syndrome is based on the administration of ENaC blockers, amiloride and triamterene. Herein, we discuss the genetic basis, clinical presentation, diagnosis and treatment of Liddle syndrome. Finally, we report a new case in an Italian family, caused by a SCNN1B p.Pro618Leu substitution.
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Chen S, Zhang Y, Wang H, Zeng YY, Li Z, Li ML, Li FF, You J, Zhang ZM, Tzeng CM. WW domain-binding protein 2 acts as an oncogene by modulating the activity of the glycolytic enzyme ENO1 in glioma. Cell Death Dis 2018; 9:347. [PMID: 29497031 PMCID: PMC5832848 DOI: 10.1038/s41419-018-0376-5] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Revised: 01/31/2018] [Accepted: 02/01/2018] [Indexed: 01/09/2023]
Abstract
WW domain-binding protein 2 (WBP2) has been demonstrated as oncogenic in breast cancer. Many studies have revealed the WBP2 gene as a high-risk gene for leukoariaosis and cerebral white matter lesions is important in the pathologic stage of glioma development. This study aimed to illustrate the underlying mechanism by which WBP2 regulates the process of glioma development. The expression pattern of WBP2 in several tumor cells was determined, clarifying the carcinogenic action of WBP2 in glioma cells. Overexpression of WBP2 in glioma cells promoted cell proliferation and migration, and the number of S-phase cells, whereas the depletion of WBP2 by RNAi-mediated knockdown restrained cell growth and cell cycle progression. Upregulation of WBP2 significantly enhanced the tumorigenic ability of U251 cells in vivo. MS/GST pulldown assay identified α-enolase (ENO1) and Homer protein homolog 3 (Homer3) as novel potent interaction partners of WBP2. Knockdown of ENO1 or Homer3 allowed cell growth and migration to return to normal levels. Furthermore, in vitro and in vivo experiments indicated that the oncogenic role of WBP2 in glioma was through modulating ENO1 and glycolysis activity via the ENO1-PI3K/Akt signaling pathway. Collectively, these results reveal that WBP2 plays a vital role in the occurrence and development of glioma, indicating a target gene for glioblastoma treatment.
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Affiliation(s)
- Shuai Chen
- Translational Medicine Research Center (TMRC), School of Pharmaceutical Science, Xiamen University, Xiamen, Fujian, 361005, P.R. China.,Department of Breast Surgery, The First Affiliated Hospital of Xiamen University, Xiamen, Fujian, 361005, P.R. China.,Key Laboratory for Cancer T-Cell Therapeutics and Clinical Translation (CTCTCT), Xiamen, Fujian, 361005, P.R. China
| | - Ya Zhang
- Translational Medicine Research Center (TMRC), School of Pharmaceutical Science, Xiamen University, Xiamen, Fujian, 361005, P.R. China.,Key Laboratory for Cancer T-Cell Therapeutics and Clinical Translation (CTCTCT), Xiamen, Fujian, 361005, P.R. China
| | - Han Wang
- Translational Medicine Research Center (TMRC), School of Pharmaceutical Science, Xiamen University, Xiamen, Fujian, 361005, P.R. China.,Key Laboratory for Cancer T-Cell Therapeutics and Clinical Translation (CTCTCT), Xiamen, Fujian, 361005, P.R. China
| | - Yu-Ying Zeng
- Department of Breast Surgery, The First Affiliated Hospital of Xiamen University, Xiamen, Fujian, 361005, P.R. China
| | - Zhi Li
- Translational Medicine Research Center (TMRC), School of Pharmaceutical Science, Xiamen University, Xiamen, Fujian, 361005, P.R. China.,Key Laboratory for Cancer T-Cell Therapeutics and Clinical Translation (CTCTCT), Xiamen, Fujian, 361005, P.R. China
| | - Ming-Li Li
- Translational Medicine Research Center (TMRC), School of Pharmaceutical Science, Xiamen University, Xiamen, Fujian, 361005, P.R. China.,Key Laboratory for Cancer T-Cell Therapeutics and Clinical Translation (CTCTCT), Xiamen, Fujian, 361005, P.R. China
| | - Fang-Fang Li
- Translational Medicine Research Center (TMRC), School of Pharmaceutical Science, Xiamen University, Xiamen, Fujian, 361005, P.R. China.,INNOVA Cell Theranostics/Clinics and TRANSLA Health Group, Yangzhou, Jiangsu, P.R. China.,Key Laboratory for Cancer T-Cell Therapeutics and Clinical Translation (CTCTCT), Xiamen, Fujian, 361005, P.R. China
| | - Jun You
- Department of Breast Surgery, The First Affiliated Hospital of Xiamen University, Xiamen, Fujian, 361005, P.R. China
| | - Zhi-Ming Zhang
- Department of Breast Surgery, The First Affiliated Hospital of Xiamen University, Xiamen, Fujian, 361005, P.R. China. .,Teaching Hospital of Fujian Medical University, Fuzhou, Fujian, 350004, P.R. China.
| | - Chi-Meng Tzeng
- Translational Medicine Research Center (TMRC), School of Pharmaceutical Science, Xiamen University, Xiamen, Fujian, 361005, P.R. China. .,INNOVA Cell Theranostics/Clinics and TRANSLA Health Group, Yangzhou, Jiangsu, P.R. China. .,Key Laboratory for Cancer T-Cell Therapeutics and Clinical Translation (CTCTCT), Xiamen, Fujian, 361005, P.R. China. .,College of Pharmaceutical Sciences, Nanjing Tech University, Nanjing, 211816, China. .,Jiansu Provincial Institute of Translation Medicine and Women-Child Health Care Hospital Affiliated to Nanjing Medical University, Nanjing, 210029, China.
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Abstract
Fierce debate has developed whether low-sodium intake, like high-sodium intake, could be associated with adverse outcome. The debate originates in earlier epidemiological studies associating high-sodium intake with high blood pressure and more recent studies demonstrating a higher cardiovascular event rate with both low- and high-sodium intake. This brings into question whether we entirely understand the consequences of high- and (very) low-sodium intake for the systemic hemodynamics, the kidney function, the vascular wall, the immune system, and the brain. Evolutionarily, sodium retention mechanisms in the context of low dietary sodium provided a survival advantage and are highly conserved, exemplified by the renin-angiotensin system. What is the potential for this sodium-retaining mechanism to cause harm? In this paper, we will consider current views on how a sodium load is handled, visiting aspects including the effect of sodium on the vessel wall, the sympathetic nervous system, the brain renin-angiotensin system, the skin as "third compartment" coupling to vascular endothelial growth factor C, and the kidneys. From these perspectives, several mechanisms can be envisioned whereby a low-sodium diet could potentially cause harm, including the renin-angiotensin system and the sympathetic nervous system. Altogether, the uncertainties preclude a unifying model or practical clinical guidance regarding the effects of a low-sodium diet for an individual. There is a very strong need for fundamental and translational studies to enhance the understanding of the potential adverse consequences of low-salt intake as an initial step to facilitate better clinical guidance.
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Affiliation(s)
- Branko Braam
- Department of Medicine, University of Alberta, Edmonton, AB, Canada. .,Department of Physiology, University of Alberta, Edmonton, AB, Canada. .,Department of Medicine / Division of Nephrology and Immunology, University of Alberta Hospital, 11-132 CSB Clinical Sciences Building, Edmonton, AB, T6G 2G3, Canada.
| | - Xiaohua Huang
- Department of Medicine, University of Alberta, Edmonton, AB, Canada
| | - William A Cupples
- Biomedical Physiology & Kinesiology, Simon Fraser University, Burnaby, BC, Canada
| | - Shereen M Hamza
- Department of Medicine, University of Alberta, Edmonton, AB, Canada.,Department of Physiology, University of Alberta, Edmonton, AB, Canada
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29
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Chronic high-sodium diet intake after weaning lead to neurogenic hypertension in adult Wistar rats. Sci Rep 2017; 7:5655. [PMID: 28720883 PMCID: PMC5515999 DOI: 10.1038/s41598-017-05984-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Accepted: 06/06/2017] [Indexed: 02/07/2023] Open
Abstract
In this study, we investigated some mechanisms involved in sodium-dependent hypertension of rats exposed to chronic salt (NaCl) intake from weaning until adult age. Weaned male Wistar rats were placed under high (0.90% w/w, HS) or regular (0.27% w/w, Cont) sodium diets for 12 weeks. Water consumption, urine output and sodium excretion were higher in HS rats compared to control. Blood pressure (BP) was directly measured by the arterial catheter and found 13.8% higher in HS vs Cont rats. Ganglionic blockade with hexamethonium caused greater fall in the BP of HS rats (33%), and central antagonism of AT1 receptors (losartan) microinjected into the lateral ventricle reduced BP level of HS, but not of Cont group. Heart rate variability analysis revealed sympathetic prevalence on modulation of the systolic interval. HS diet did not affect creatinine clearance. Kidney histological analysis revealed no significant change in renal corpuscle structure. Sodium and potassium concentrations in CSF were found higher in HS rats despite no change in plasma concentration of these ions. Taken together, data suggest that animals exposed to chronic salt intake to a level close to that reported for human' diet since weaning lead to hypertension, which appears to rely on sodium-driven neurogenic mechanisms.
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30
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Wang ZR, Liu HB, Sun YY, Hu QQ, Li YX, Zheng WW, Yu CJ, Li XY, Wu MM, Song BL, Mu JJ, Yuan ZY, Zhang ZR, Ma HP. Dietary salt blunts vasodilation by stimulating epithelial sodium channels in endothelial cells from salt-sensitive Dahl rats. Br J Pharmacol 2017; 175:1305-1317. [PMID: 28409833 DOI: 10.1111/bph.13817] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Revised: 03/26/2017] [Accepted: 04/04/2017] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND AND PURPOSE Our recent studies show that the reduced activity of epithelial sodium channels (ENaC) in endothelial cells accounts for the adaptation of vasculature to salt in Sprague-Dawley rats. The present study examines a hypothesis that enhanced ENaC activity mediates the loss of vasorelaxation in Dahl salt-sensitive (SS) rats. EXPERIMENTAL APPROACH We used the cell-attached patch-clamp technique to record ENaC activity in split-open mesenteric arteries. Western blot and immunofluorescence staining were used to evaluate the levels of aldosterone, ENaC, eNOS and NO. Blood pressure was measured with the tail-cuff method and the artery relaxation was measured with the wire myograph assay. KEY RESULTS High-salt (HS) diet significantly increased plasma aldosterone and ENaC activity in the endothelial cells of Dahl SS rats. The endothelium-dependent artery relaxation was blunted by HS challenge in these rats. Amiloride, a potent blocker of ENaC, increased both phosphorylated eNOS and NO and therefore prevented the HS-induced loss of vasorelaxation. As, in SS rats, endogenous aldosterone was already elevated by HS challenge, exogenous aldosterone did not further elevate ENaC activity in the rats fed with HS. Eplerenone, a mineralocorticoid receptor antagonist, attenuated the effects of HS on both ENaC activity and artery relaxation. CONCLUSIONS AND IMPLICATIONS These data suggest that HS diet blunts artery relaxation and causes hypertension via a pathway associated with aldosterone-dependent activation of ENaC in endothelial cells. This pathway provides one of the mechanisms by which HS causes hypertension in Dahl SS rats. LINKED ARTICLES This article is part of a themed section on Spotlight on Small Molecules in Cardiovascular Diseases. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v175.8/issuetoc.
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Affiliation(s)
- Zi-Rui Wang
- Departments of Cardiology and Clinical Pharmacy, Harbin Medical University Cancer Hospital, Institute of Metabolic Disease, Heilongjiang Academy of Medical Science, Key Laboratories of Education Ministry for Myocardial Ischemia Mechanism and Treatment, Harbin, China
| | - Hui-Bin Liu
- Department of Clinical Pharmacy, Institute of Clinical Pharmacy, the 2nd Affiliated Hospital, Harbin Medical University, Harbin, China
| | - Ying-Ying Sun
- State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Qing-Qing Hu
- Departments of Cardiology and Clinical Pharmacy, Harbin Medical University Cancer Hospital, Institute of Metabolic Disease, Heilongjiang Academy of Medical Science, Key Laboratories of Education Ministry for Myocardial Ischemia Mechanism and Treatment, Harbin, China
| | - Yu-Xia Li
- Departments of Cardiology and Clinical Pharmacy, Harbin Medical University Cancer Hospital, Institute of Metabolic Disease, Heilongjiang Academy of Medical Science, Key Laboratories of Education Ministry for Myocardial Ischemia Mechanism and Treatment, Harbin, China
| | - Wei-Wan Zheng
- Departments of Cardiology and Clinical Pharmacy, Harbin Medical University Cancer Hospital, Institute of Metabolic Disease, Heilongjiang Academy of Medical Science, Key Laboratories of Education Ministry for Myocardial Ischemia Mechanism and Treatment, Harbin, China
| | - Chang-Jiang Yu
- Departments of Cardiology and Clinical Pharmacy, Harbin Medical University Cancer Hospital, Institute of Metabolic Disease, Heilongjiang Academy of Medical Science, Key Laboratories of Education Ministry for Myocardial Ischemia Mechanism and Treatment, Harbin, China
| | - Xin-Yuan Li
- Departments of Cardiology and Clinical Pharmacy, Harbin Medical University Cancer Hospital, Institute of Metabolic Disease, Heilongjiang Academy of Medical Science, Key Laboratories of Education Ministry for Myocardial Ischemia Mechanism and Treatment, Harbin, China
| | - Ming-Ming Wu
- Departments of Cardiology and Clinical Pharmacy, Harbin Medical University Cancer Hospital, Institute of Metabolic Disease, Heilongjiang Academy of Medical Science, Key Laboratories of Education Ministry for Myocardial Ischemia Mechanism and Treatment, Harbin, China
| | - Bin-Lin Song
- Departments of Cardiology and Clinical Pharmacy, Harbin Medical University Cancer Hospital, Institute of Metabolic Disease, Heilongjiang Academy of Medical Science, Key Laboratories of Education Ministry for Myocardial Ischemia Mechanism and Treatment, Harbin, China
| | - Jian-Jun Mu
- Department of Cardiovascular Medicine, First Affiliated Hospital of Medical College of Xi'an Jiaotong University, Key Laboratory of Molecular Cardiology, Xi'an, China
| | - Zu-Yi Yuan
- Department of Cardiovascular Medicine, First Affiliated Hospital of Medical College of Xi'an Jiaotong University, Key Laboratory of Molecular Cardiology, Xi'an, China
| | - Zhi-Ren Zhang
- Departments of Cardiology and Clinical Pharmacy, Harbin Medical University Cancer Hospital, Institute of Metabolic Disease, Heilongjiang Academy of Medical Science, Key Laboratories of Education Ministry for Myocardial Ischemia Mechanism and Treatment, Harbin, China.,Department of Clinical Pharmacy, Institute of Clinical Pharmacy, the 2nd Affiliated Hospital, Harbin Medical University, Harbin, China
| | - He-Ping Ma
- Department of Physiology, Emory University School of Medicine, Atlanta, GA, USA
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31
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Praetorius J, Damkier HH. Transport across the choroid plexus epithelium. Am J Physiol Cell Physiol 2017; 312:C673-C686. [PMID: 28330845 DOI: 10.1152/ajpcell.00041.2017] [Citation(s) in RCA: 74] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Revised: 03/17/2017] [Accepted: 03/17/2017] [Indexed: 11/22/2022]
Abstract
The choroid plexus epithelium is a secretory epithelium par excellence. However, this is perhaps not the most prominent reason for the massive interest in this modest-sized tissue residing inside the brain ventricles. Most likely, the dominant reason for extensive studies of the choroid plexus is the identification of this epithelium as the source of the majority of intraventricular cerebrospinal fluid. This finding has direct relevance for studies of diseases and conditions with deranged central fluid volume or ionic balance. While the concept is supported by the vast majority of the literature, the implication of the choroid plexus in secretion of the cerebrospinal fluid was recently challenged once again. Three newer and promising areas of current choroid plexus-related investigations are as follows: 1) the choroid plexus epithelium as the source of mediators necessary for central nervous system development, 2) the choroid plexus as a route for microorganisms and immune cells into the central nervous system, and 3) the choroid plexus as a potential route for drug delivery into the central nervous system, bypassing the blood-brain barrier. Thus, the purpose of this review is to highlight current active areas of research in the choroid plexus physiology and a few matters of continuous controversy.
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Affiliation(s)
- Jeppe Praetorius
- Department of Biomedicine, Health, Aarhus University, Aarhus, Denmark; and
| | - Helle Hasager Damkier
- Department of Biomedicine, Health, Aarhus University, Aarhus, Denmark; and.,Department of Cellular and Molecular Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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32
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Nedd4-2 haploinsufficiency causes hyperactivity and increased sensitivity to inflammatory stimuli. Sci Rep 2016; 6:32957. [PMID: 27604420 PMCID: PMC5015076 DOI: 10.1038/srep32957] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Accepted: 08/16/2016] [Indexed: 01/01/2023] Open
Abstract
Nedd4-2 (NEDD4L in humans) is a ubiquitin protein ligase best known for its role in regulating ion channel internalization and turnover. Nedd4-2 deletion in mice causes perinatal lethality associated with increased epithelial sodium channel (ENaC) expression in lung and kidney. Abundant data suggest that Nedd4-2 plays a role in neuronal functions and may be linked to epilepsy and dyslexia in humans. We used a mouse model of Nedd4-2 haploinsufficiency to investigate whether an alteration in Nedd4-2 levels of expression affects general nervous system functions. We found that Nedd4-2 heterozygous mice are hyperactive, have increased basal synaptic transmission and have enhanced sensitivity to inflammatory pain. Thus, Nedd4-2 heterozygous mice provide a new genetic model to study inflammatory pain. These data also suggest that in human, SNPs affecting NEDD4L levels may be involved in the development of neuropsychological deficits and peripheral neuropathies and may help unveil the genetic basis of comorbidities.
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33
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Mansley MK, Ivy JR, Bailey MA. ISN Forefronts Symposium 2015: The Evolution of Hypertension-Old Genes, New Concepts. Kidney Int Rep 2016; 1:197-203. [PMID: 27722209 PMCID: PMC5044930 DOI: 10.1016/j.ekir.2016.08.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Revised: 07/26/2016] [Accepted: 08/02/2016] [Indexed: 12/17/2022] Open
Abstract
Hypertension is known as the “silent killer,” driving the global public health burden of cardiovascular and renal disease. Blood pressure homeostasis is intimately associated with sodium balance and the distribution of sodium between fluid compartments and within tissues. On a population level, most societies consume 10 times more salt that the 0.5 g required by physiological need. This high salt intake is strongly linked to hypertension and to the World Health Organization targeting a ∼30% relative reduction in mean population salt intake to arrest the global mortality due to cardiovascular disease. But how does a habitually high-salt diet cause blood pressure to rise? In this focused review, we discuss 2 “evolutionary medicine” concepts, presented at the ISN Forefront Meeting “Immunomodulation of Cardio-renal Function.” We first examine how ancestral variants in genes that conferred a selection advantage during early human development are now maladaptive. We then discuss the conservation of “renal” sodium transport processes across multiple organ systems, including the brain. These systems influence sodium appetite and can exert an often-overlooked effect on long-term blood pressure control.
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Affiliation(s)
- Morag K Mansley
- The British Heart Foundation Centre for Cardiovascular Science, The University of Edinburgh, Edinburgh, UK
| | - Jessica R Ivy
- The British Heart Foundation Centre for Cardiovascular Science, The University of Edinburgh, Edinburgh, UK
| | - Matthew A Bailey
- The British Heart Foundation Centre for Cardiovascular Science, The University of Edinburgh, Edinburgh, UK
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34
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Blaustein MP, Chen L, Hamlyn JM, Leenen FHH, Lingrel JB, Wier WG, Zhang J. Pivotal role of α2 Na + pumps and their high affinity ouabain binding site in cardiovascular health and disease. J Physiol 2016; 594:6079-6103. [PMID: 27350568 DOI: 10.1113/jp272419] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Accepted: 06/18/2016] [Indexed: 12/13/2022] Open
Abstract
Reduced smooth muscle (SM)-specific α2 Na+ pump expression elevates basal blood pressure (BP) and increases BP sensitivity to angiotensin II (Ang II) and dietary NaCl, whilst SM-α2 overexpression lowers basal BP and decreases Ang II/salt sensitivity. Prolonged ouabain infusion induces hypertension in rodents, and ouabain-resistant mutation of the α2 ouabain binding site (α2R/R mice) confers resistance to several forms of hypertension. Pressure overload-induced heart hypertrophy and failure are attenuated in cardio-specific α2 knockout, cardio-specific α2 overexpression and α2R/R mice. We propose a unifying hypothesis that reconciles these apparently disparate findings: brain mechanisms, activated by Ang II and high NaCl, regulate sympathetic drive and a novel neurohumoral pathway mediated by both brain and circulating endogenous ouabain (EO). Circulating EO modulates ouabain-sensitive α2 Na+ pump activity and Ca2+ transporter expression and, via Na+ /Ca2+ exchange, Ca2+ homeostasis. This regulates sensitivity to sympathetic activity, Ca2+ signalling and arterial and cardiac contraction.
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Affiliation(s)
- Mordecai P Blaustein
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA. .,Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, 21201, USA.
| | - Ling Chen
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA.,Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - John M Hamlyn
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - Frans H H Leenen
- Hypertension Unit, University of Ottawa Heart Institute, Ottawa, ON, Canada, K1Y 4W7
| | - Jerry B Lingrel
- Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati College of Medicine, Cincinnati, OH, 45267-0524, USA
| | - W Gil Wier
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - Jin Zhang
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
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35
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Affiliation(s)
- John M Hamlyn
- From the Departments of Physiology (J.M.H., M.P.B.) and Medicine (M.P.B.), University of Maryland School of Medicine, Baltimore.
| | - Mordecai P Blaustein
- From the Departments of Physiology (J.M.H., M.P.B.) and Medicine (M.P.B.), University of Maryland School of Medicine, Baltimore.
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36
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Elijovich F, Weinberger MH, Anderson CAM, Appel LJ, Bursztyn M, Cook NR, Dart RA, Newton-Cheh CH, Sacks FM, Laffer CL. Salt Sensitivity of Blood Pressure: A Scientific Statement From the American Heart Association. Hypertension 2016; 68:e7-e46. [PMID: 27443572 DOI: 10.1161/hyp.0000000000000047] [Citation(s) in RCA: 326] [Impact Index Per Article: 40.8] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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37
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Morris RC, Schmidlin O, Sebastian A, Tanaka M, Kurtz TW. Vasodysfunction That Involves Renal Vasodysfunction, Not Abnormally Increased Renal Retention of Sodium, Accounts for the Initiation of Salt-Induced Hypertension. Circulation 2016; 133:881-93. [PMID: 26927006 DOI: 10.1161/circulationaha.115.017923] [Citation(s) in RCA: 86] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- R Curtis Morris
- From the Departments of Medicine (R.C.M., O.S., A.S., M.T.) and Laboratory Medicine (T.W.K.), University of California, San Francisco.
| | - Olga Schmidlin
- From the Departments of Medicine (R.C.M., O.S., A.S., M.T.) and Laboratory Medicine (T.W.K.), University of California, San Francisco
| | - Anthony Sebastian
- From the Departments of Medicine (R.C.M., O.S., A.S., M.T.) and Laboratory Medicine (T.W.K.), University of California, San Francisco
| | - Masae Tanaka
- From the Departments of Medicine (R.C.M., O.S., A.S., M.T.) and Laboratory Medicine (T.W.K.), University of California, San Francisco
| | - Theodore W Kurtz
- From the Departments of Medicine (R.C.M., O.S., A.S., M.T.) and Laboratory Medicine (T.W.K.), University of California, San Francisco.
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38
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Abstract
Sympathetic nerve activity is involved in the pathogenesis of salt-sensitive hypertension. The central nervous system, which regulates sympathetic nerve activity and blood pressure, plays a pivotal role. Central sympathoexcitation is deeply involved in the pathogenesis of salt-sensitive hypertension, although the precise mechanisms have not been fully elucidated because of their complexity. The role of brain oxidative stress in sympathoexcitation has been suggested in some types of hypertensive animal models. We have shown that increased brain oxidative stress may elevate arterial pressure through central sympathoexcitation in salt-sensitive hypertension. Several other factors such as mineralocorticoid receptors, aldosterone, corticosterone, epithelial sodium channels, and angiotensin II also play important roles in central sympathetic activation, some of which can be associated with brain oxidative stress. Furthermore, brain paraventricular nucleus Gαi2-protein-mediated transduction has been recently reported as a candidate for the molecular mechanism countering the development of salt-sensitive hypertension.
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Minegishi S, Ishigami T, Kino T, Chen L, Nakashima-Sasaki R, Araki N, Yatsu K, Fujita M, Umemura S. An isoform of Nedd4-2 is critically involved in the renal adaptation to high salt intake in mice. Sci Rep 2016; 6:27137. [PMID: 27256588 PMCID: PMC4891730 DOI: 10.1038/srep27137] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2015] [Accepted: 05/13/2016] [Indexed: 11/14/2022] Open
Abstract
Epithelial sodium channels (ENaCs) play critical roles in the maintenance of fluid and electrolyte homeostasis, and their genetic abnormalities cause one type of hereditary salt-sensitive hypertension, Liddle syndrome. As we reported previously, both human and rodent Nedd4L/Nedd4-2 showed molecular diversity, with and without a C2 domain in their N-terminal. Nedd4L/Nedd4-2 isoforms with a C2 domain are hypothesized to be related closely to ubiquitination of ENaCs. We generated Nedd4-2 C2 domain knockout mice. We demonstrate here that loss of Nedd4-2 C2 isoform causes salt-sensitive hypertension under conditions of a high dietary salt intake in vivo. The knockout mice had reduced urinary sodium excretion, osmotic pressure and increased water intake and urine volume with marked dilatation of cortical tubules while receiving a high salt diet. To the contrary, there was no difference in metabolic data between wild-type and knockout mice receiving a normal control diet. In the absence of Nedd4-2 C2 domain, a high salt intake accelerated ENaC expression. Coimmunoprecipitation studies revealed suppressed ubiquitination for ENaC with a high salt intake. Taken together, our findings demonstrate that during a high oral salt intake the Nedd4-2 C2 protein plays a pivotal role in maintaining adaptive salt handling in the kidney.
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Affiliation(s)
- Shintaro Minegishi
- Yokohama City University Graduate School of Medicine, Department of Medical Science and Cardio-Renal Medicine
| | - Tomoaki Ishigami
- Yokohama City University Graduate School of Medicine, Department of Medical Science and Cardio-Renal Medicine
| | - Tabito Kino
- Yokohama City University Graduate School of Medicine, Department of Medical Science and Cardio-Renal Medicine
| | - Lin Chen
- Yokohama City University Graduate School of Medicine, Department of Medical Science and Cardio-Renal Medicine
| | - Rie Nakashima-Sasaki
- Yokohama City University Graduate School of Medicine, Department of Medical Science and Cardio-Renal Medicine
| | - Naomi Araki
- Yokohama City University Graduate School of Medicine, Department of Medical Science and Cardio-Renal Medicine
| | - Keisuke Yatsu
- Yokohama City University Graduate School of Medicine, Department of Medical Science and Cardio-Renal Medicine
| | - Megumi Fujita
- Yokohama City University Graduate School of Medicine, Department of Medical Science and Cardio-Renal Medicine
| | - Satoshi Umemura
- Yokohama City University Graduate School of Medicine, Department of Medical Science and Cardio-Renal Medicine
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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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Evans LC, Ivy JR, Wyrwoll C, McNairn JA, Menzies RI, Christensen TH, Al-Dujaili EAS, Kenyon CJ, Mullins JJ, Seckl JR, Holmes MC, Bailey MA. Conditional Deletion of Hsd11b2 in the Brain Causes Salt Appetite and Hypertension. Circulation 2016; 133:1360-70. [PMID: 26951843 PMCID: PMC4819772 DOI: 10.1161/circulationaha.115.019341] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Accepted: 02/12/2016] [Indexed: 11/30/2022]
Abstract
Supplemental Digital Content is available in the text. Background— The hypertensive syndrome of Apparent Mineralocorticoid Excess is caused by loss-of-function mutations in the gene encoding 11β-hydroxysteroid dehydrogenase type 2 (11βHSD2), allowing inappropriate activation of the mineralocorticoid receptor by endogenous glucocorticoid. Hypertension is attributed to sodium retention in the distal nephron, but 11βHSD2 is also expressed in the brain. However, the central contribution to Apparent Mineralocorticoid Excess and other hypertensive states is often overlooked and is unresolved. We therefore used a Cre-Lox strategy to generate 11βHSD2 brain-specific knockout (Hsd11b2.BKO) mice, measuring blood pressure and salt appetite in adults. Methods and Results— Basal blood pressure, electrolytes, and circulating corticosteroids were unaffected in Hsd11b2.BKO mice. When offered saline to drink, Hsd11b2.BKO mice consumed 3 times more sodium than controls and became hypertensive. Salt appetite was inhibited by spironolactone. Control mice fed the same daily sodium intake remained normotensive, showing the intrinsic salt resistance of the background strain. Dexamethasone suppressed endogenous glucocorticoid and abolished the salt-induced blood pressure differential between genotypes. Salt sensitivity in Hsd11b2.BKO mice was not caused by impaired renal sodium excretion or volume expansion; pressor responses to phenylephrine were enhanced and baroreflexes impaired in these animals. Conclusions— Reduced 11βHSD2 activity in the brain does not intrinsically cause hypertension, but it promotes a hunger for salt and a transition from salt resistance to salt sensitivity. Our data suggest that 11βHSD2-positive neurons integrate salt appetite and the blood pressure response to dietary sodium through a mineralocorticoid receptor–dependent pathway. Therefore, central mineralocorticoid receptor antagonism could increase compliance to low-sodium regimens and help blood pressure management in cardiovascular disease.
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Affiliation(s)
- Louise C Evans
- From British Heart Foundation Centre for Cardiovascular Science, The University of Edinburgh, United Kingdom (L.C.E., J.R.I., C.W., J.A.M., R.I.M., T.H.C., C.J.K., J.J.M., J.R.S., M.C.H., M.A.B.); and Dietetics, Nutrition and Biological Sciences Department, Queen Margaret University, Edinburgh, United Kingdom (E.A.S.Al-D.). The current address for Dr Evans is Department of Physiology, Cardiovascular Center, Medical College of Wisconsin, Milwaukee; the current address for Dr Wyrwoll is School of Anatomy, Physiology & Human Biology, The University of Western Australia, Crawley, Australia; and the current address for Dr Christensen is Department of Cardiovascular and Renal Research, University of Southern Denmark, Odense
| | - Jessica R Ivy
- From British Heart Foundation Centre for Cardiovascular Science, The University of Edinburgh, United Kingdom (L.C.E., J.R.I., C.W., J.A.M., R.I.M., T.H.C., C.J.K., J.J.M., J.R.S., M.C.H., M.A.B.); and Dietetics, Nutrition and Biological Sciences Department, Queen Margaret University, Edinburgh, United Kingdom (E.A.S.Al-D.). The current address for Dr Evans is Department of Physiology, Cardiovascular Center, Medical College of Wisconsin, Milwaukee; the current address for Dr Wyrwoll is School of Anatomy, Physiology & Human Biology, The University of Western Australia, Crawley, Australia; and the current address for Dr Christensen is Department of Cardiovascular and Renal Research, University of Southern Denmark, Odense
| | - Caitlin Wyrwoll
- From British Heart Foundation Centre for Cardiovascular Science, The University of Edinburgh, United Kingdom (L.C.E., J.R.I., C.W., J.A.M., R.I.M., T.H.C., C.J.K., J.J.M., J.R.S., M.C.H., M.A.B.); and Dietetics, Nutrition and Biological Sciences Department, Queen Margaret University, Edinburgh, United Kingdom (E.A.S.Al-D.). The current address for Dr Evans is Department of Physiology, Cardiovascular Center, Medical College of Wisconsin, Milwaukee; the current address for Dr Wyrwoll is School of Anatomy, Physiology & Human Biology, The University of Western Australia, Crawley, Australia; and the current address for Dr Christensen is Department of Cardiovascular and Renal Research, University of Southern Denmark, Odense
| | - Julie A McNairn
- From British Heart Foundation Centre for Cardiovascular Science, The University of Edinburgh, United Kingdom (L.C.E., J.R.I., C.W., J.A.M., R.I.M., T.H.C., C.J.K., J.J.M., J.R.S., M.C.H., M.A.B.); and Dietetics, Nutrition and Biological Sciences Department, Queen Margaret University, Edinburgh, United Kingdom (E.A.S.Al-D.). The current address for Dr Evans is Department of Physiology, Cardiovascular Center, Medical College of Wisconsin, Milwaukee; the current address for Dr Wyrwoll is School of Anatomy, Physiology & Human Biology, The University of Western Australia, Crawley, Australia; and the current address for Dr Christensen is Department of Cardiovascular and Renal Research, University of Southern Denmark, Odense
| | - Robert I Menzies
- From British Heart Foundation Centre for Cardiovascular Science, The University of Edinburgh, United Kingdom (L.C.E., J.R.I., C.W., J.A.M., R.I.M., T.H.C., C.J.K., J.J.M., J.R.S., M.C.H., M.A.B.); and Dietetics, Nutrition and Biological Sciences Department, Queen Margaret University, Edinburgh, United Kingdom (E.A.S.Al-D.). The current address for Dr Evans is Department of Physiology, Cardiovascular Center, Medical College of Wisconsin, Milwaukee; the current address for Dr Wyrwoll is School of Anatomy, Physiology & Human Biology, The University of Western Australia, Crawley, Australia; and the current address for Dr Christensen is Department of Cardiovascular and Renal Research, University of Southern Denmark, Odense
| | - Thorbjørn H Christensen
- From British Heart Foundation Centre for Cardiovascular Science, The University of Edinburgh, United Kingdom (L.C.E., J.R.I., C.W., J.A.M., R.I.M., T.H.C., C.J.K., J.J.M., J.R.S., M.C.H., M.A.B.); and Dietetics, Nutrition and Biological Sciences Department, Queen Margaret University, Edinburgh, United Kingdom (E.A.S.Al-D.). The current address for Dr Evans is Department of Physiology, Cardiovascular Center, Medical College of Wisconsin, Milwaukee; the current address for Dr Wyrwoll is School of Anatomy, Physiology & Human Biology, The University of Western Australia, Crawley, Australia; and the current address for Dr Christensen is Department of Cardiovascular and Renal Research, University of Southern Denmark, Odense
| | - Emad A S Al-Dujaili
- From British Heart Foundation Centre for Cardiovascular Science, The University of Edinburgh, United Kingdom (L.C.E., J.R.I., C.W., J.A.M., R.I.M., T.H.C., C.J.K., J.J.M., J.R.S., M.C.H., M.A.B.); and Dietetics, Nutrition and Biological Sciences Department, Queen Margaret University, Edinburgh, United Kingdom (E.A.S.Al-D.). The current address for Dr Evans is Department of Physiology, Cardiovascular Center, Medical College of Wisconsin, Milwaukee; the current address for Dr Wyrwoll is School of Anatomy, Physiology & Human Biology, The University of Western Australia, Crawley, Australia; and the current address for Dr Christensen is Department of Cardiovascular and Renal Research, University of Southern Denmark, Odense
| | - Christopher J Kenyon
- From British Heart Foundation Centre for Cardiovascular Science, The University of Edinburgh, United Kingdom (L.C.E., J.R.I., C.W., J.A.M., R.I.M., T.H.C., C.J.K., J.J.M., J.R.S., M.C.H., M.A.B.); and Dietetics, Nutrition and Biological Sciences Department, Queen Margaret University, Edinburgh, United Kingdom (E.A.S.Al-D.). The current address for Dr Evans is Department of Physiology, Cardiovascular Center, Medical College of Wisconsin, Milwaukee; the current address for Dr Wyrwoll is School of Anatomy, Physiology & Human Biology, The University of Western Australia, Crawley, Australia; and the current address for Dr Christensen is Department of Cardiovascular and Renal Research, University of Southern Denmark, Odense
| | - John J Mullins
- From British Heart Foundation Centre for Cardiovascular Science, The University of Edinburgh, United Kingdom (L.C.E., J.R.I., C.W., J.A.M., R.I.M., T.H.C., C.J.K., J.J.M., J.R.S., M.C.H., M.A.B.); and Dietetics, Nutrition and Biological Sciences Department, Queen Margaret University, Edinburgh, United Kingdom (E.A.S.Al-D.). The current address for Dr Evans is Department of Physiology, Cardiovascular Center, Medical College of Wisconsin, Milwaukee; the current address for Dr Wyrwoll is School of Anatomy, Physiology & Human Biology, The University of Western Australia, Crawley, Australia; and the current address for Dr Christensen is Department of Cardiovascular and Renal Research, University of Southern Denmark, Odense
| | - Jonathan R Seckl
- From British Heart Foundation Centre for Cardiovascular Science, The University of Edinburgh, United Kingdom (L.C.E., J.R.I., C.W., J.A.M., R.I.M., T.H.C., C.J.K., J.J.M., J.R.S., M.C.H., M.A.B.); and Dietetics, Nutrition and Biological Sciences Department, Queen Margaret University, Edinburgh, United Kingdom (E.A.S.Al-D.). The current address for Dr Evans is Department of Physiology, Cardiovascular Center, Medical College of Wisconsin, Milwaukee; the current address for Dr Wyrwoll is School of Anatomy, Physiology & Human Biology, The University of Western Australia, Crawley, Australia; and the current address for Dr Christensen is Department of Cardiovascular and Renal Research, University of Southern Denmark, Odense
| | - Megan C Holmes
- From British Heart Foundation Centre for Cardiovascular Science, The University of Edinburgh, United Kingdom (L.C.E., J.R.I., C.W., J.A.M., R.I.M., T.H.C., C.J.K., J.J.M., J.R.S., M.C.H., M.A.B.); and Dietetics, Nutrition and Biological Sciences Department, Queen Margaret University, Edinburgh, United Kingdom (E.A.S.Al-D.). The current address for Dr Evans is Department of Physiology, Cardiovascular Center, Medical College of Wisconsin, Milwaukee; the current address for Dr Wyrwoll is School of Anatomy, Physiology & Human Biology, The University of Western Australia, Crawley, Australia; and the current address for Dr Christensen is Department of Cardiovascular and Renal Research, University of Southern Denmark, Odense
| | - Matthew A Bailey
- From British Heart Foundation Centre for Cardiovascular Science, The University of Edinburgh, United Kingdom (L.C.E., J.R.I., C.W., J.A.M., R.I.M., T.H.C., C.J.K., J.J.M., J.R.S., M.C.H., M.A.B.); and Dietetics, Nutrition and Biological Sciences Department, Queen Margaret University, Edinburgh, United Kingdom (E.A.S.Al-D.). The current address for Dr Evans is Department of Physiology, Cardiovascular Center, Medical College of Wisconsin, Milwaukee; the current address for Dr Wyrwoll is School of Anatomy, Physiology & Human Biology, The University of Western Australia, Crawley, Australia; and the current address for Dr Christensen is Department of Cardiovascular and Renal Research, University of Southern Denmark, Odense.
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Role of brain aldosterone and mineralocorticoid receptors in aldosterone-salt hypertension in rats. Neuroscience 2016; 314:90-105. [DOI: 10.1016/j.neuroscience.2015.11.055] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Revised: 11/09/2015] [Accepted: 11/23/2015] [Indexed: 11/23/2022]
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Mizuno M, Mitchell JH, Smith SA. The exercise pressor reflex in hypertension. THE JOURNAL OF PHYSICAL FITNESS AND SPORTS MEDICINE 2016. [DOI: 10.7600/jpfsm.5.339] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Masaki Mizuno
- Department of Health Care Sciences, University of Texas Southwestern Medical Center
- Internal Medicine, University of Texas Southwestern Medical Center
| | - Jere H. Mitchell
- Internal Medicine, University of Texas Southwestern Medical Center
| | - Scott A. Smith
- Department of Health Care Sciences, University of Texas Southwestern Medical Center
- Internal Medicine, University of Texas Southwestern Medical Center
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Mizuno M, Downey RM, Mitchell JH, Auchus RJ, Smith SA, Vongpatanasin W. Aldosterone and Salt Loading Independently Exacerbate the Exercise Pressor Reflex in Rats. Hypertension 2015. [PMID: 26195483 DOI: 10.1161/hypertensionaha.115.05810] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The sympathetic and pressor responses to exercise are exaggerated in hypertension. Evidence suggests that an overactive exercise pressor reflex (EPR) contributes to this abnormal responsiveness. The mechanisms underlying this EPR overactivity are poorly understood. An increasing body of evidence suggests that aldosterone and excessive salt intake play a role in regulating resting sympathetic activity and blood pressure in hypertension. Therefore, each is a good candidate for the generation of EPR dysfunction in this disease. The purpose of this study was to examine whether excessive salt intake and chronic administration of aldosterone potentiate EPR function. Changes in mean arterial pressure and renal sympathetic nerve activity induced by EPR stimulation were examined in vehicle and aldosterone-treated (4 weeks via osmotic mini-pump) Sprague-Dawley rats given either water or saline (elevated salt load) to drink. When compared with vehicle/water-treated rats, stimulation of the EPR by muscle contraction evoked significantly greater increases in mean arterial pressure in vehicle/saline, aldosterone/water, and aldosterone/saline-treated animals (14±3, 29±3, 37±6, and 44±7 mm Hg/kg, respectively; P<0.01). A similar renal sympathetic nerve activity response profile was likewise produced (39±11%, 87±15%, 110±20%, and 151±25%/kg, respectively; P<0.01). The pressor and sympathetic responses to the individual activation of the mechanically and chemically sensitive components of the EPR were also augmented by both saline and aldosterone. These data provide the first direct evidence that both aldosterone and high salt intake elicit EPR overactivity. As such, each represents a potential mechanism by which sympathetic activity and blood pressure are augmented during exercise in hypertension.
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Affiliation(s)
- Masaki Mizuno
- From the Departments of Health Care Sciences (M.M., S.A.S.) and Internal Medicine (M.M., R.M.D., J.H.M., S.A.S., W.V.) and Hypertension Section, Cardiology Division (W.V.), University of Texas Southwestern Medical Center, Dallas; and Department of Internal Medicine, University of Michigan Medical School, Ann Arbor (R.J.A.)
| | - Ryan M Downey
- From the Departments of Health Care Sciences (M.M., S.A.S.) and Internal Medicine (M.M., R.M.D., J.H.M., S.A.S., W.V.) and Hypertension Section, Cardiology Division (W.V.), University of Texas Southwestern Medical Center, Dallas; and Department of Internal Medicine, University of Michigan Medical School, Ann Arbor (R.J.A.)
| | - Jere H Mitchell
- From the Departments of Health Care Sciences (M.M., S.A.S.) and Internal Medicine (M.M., R.M.D., J.H.M., S.A.S., W.V.) and Hypertension Section, Cardiology Division (W.V.), University of Texas Southwestern Medical Center, Dallas; and Department of Internal Medicine, University of Michigan Medical School, Ann Arbor (R.J.A.)
| | - Richard J Auchus
- From the Departments of Health Care Sciences (M.M., S.A.S.) and Internal Medicine (M.M., R.M.D., J.H.M., S.A.S., W.V.) and Hypertension Section, Cardiology Division (W.V.), University of Texas Southwestern Medical Center, Dallas; and Department of Internal Medicine, University of Michigan Medical School, Ann Arbor (R.J.A.)
| | - Scott A Smith
- From the Departments of Health Care Sciences (M.M., S.A.S.) and Internal Medicine (M.M., R.M.D., J.H.M., S.A.S., W.V.) and Hypertension Section, Cardiology Division (W.V.), University of Texas Southwestern Medical Center, Dallas; and Department of Internal Medicine, University of Michigan Medical School, Ann Arbor (R.J.A.)
| | - Wanpen Vongpatanasin
- From the Departments of Health Care Sciences (M.M., S.A.S.) and Internal Medicine (M.M., R.M.D., J.H.M., S.A.S., W.V.) and Hypertension Section, Cardiology Division (W.V.), University of Texas Southwestern Medical Center, Dallas; and Department of Internal Medicine, University of Michigan Medical School, Ann Arbor (R.J.A.).
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Wang LP, Yang KQ, Jiang XJ, Wu HY, Zhang HM, Zou YB, Song L, Bian J, Hui RT, Liu YX, Zhou XL. Prevalence of Liddle Syndrome Among Young Hypertension Patients of Undetermined Cause in a Chinese Population. J Clin Hypertens (Greenwich) 2015; 17:902-7. [PMID: 26075967 DOI: 10.1111/jch.12598] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2015] [Revised: 04/14/2015] [Accepted: 04/19/2015] [Indexed: 11/28/2022]
Affiliation(s)
- Lin-Ping Wang
- Department of Cardiology; Fuwai Hospital; National Center for Cardiovascular Disease; Chinese Academy of Medical Sciences and Peking Union Medical College; Beijing China
| | - Kun-Qi Yang
- Department of Cardiology; Fuwai Hospital; National Center for Cardiovascular Disease; Chinese Academy of Medical Sciences and Peking Union Medical College; Beijing China
| | - Xiong-Jing Jiang
- Department of Cardiology; Fuwai Hospital; National Center for Cardiovascular Disease; Chinese Academy of Medical Sciences and Peking Union Medical College; Beijing China
| | - Hai-Ying Wu
- Department of Cardiology; Fuwai Hospital; National Center for Cardiovascular Disease; Chinese Academy of Medical Sciences and Peking Union Medical College; Beijing China
| | - Hui-Min Zhang
- Department of Cardiology; Fuwai Hospital; National Center for Cardiovascular Disease; Chinese Academy of Medical Sciences and Peking Union Medical College; Beijing China
| | - Yu-Bao Zou
- Department of Cardiology; Fuwai Hospital; National Center for Cardiovascular Disease; Chinese Academy of Medical Sciences and Peking Union Medical College; Beijing China
| | - Lei Song
- Department of Cardiology; Fuwai Hospital; National Center for Cardiovascular Disease; Chinese Academy of Medical Sciences and Peking Union Medical College; Beijing China
| | - Jin Bian
- Department of Cardiology; Fuwai Hospital; National Center for Cardiovascular Disease; Chinese Academy of Medical Sciences and Peking Union Medical College; Beijing China
| | - Ru-Tai Hui
- Department of Cardiology; Fuwai Hospital; National Center for Cardiovascular Disease; Chinese Academy of Medical Sciences and Peking Union Medical College; Beijing China
- State Key Laboratory of Cardiovascular Disease; Sino-German Laboratory for Molecular Medicine; Fuwai Hospital; National Center for Cardiovascular Diseases; Chinese Academy of Medical Sciences and Peking Union Medical College; Beijing China
| | - Ya-Xin Liu
- Department of Cardiology; Fuwai Hospital; National Center for Cardiovascular Disease; Chinese Academy of Medical Sciences and Peking Union Medical College; Beijing China
| | - Xian-Liang Zhou
- Department of Cardiology; Fuwai Hospital; National Center for Cardiovascular Disease; Chinese Academy of Medical Sciences and Peking Union Medical College; Beijing China
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Leenen FHH, Hou X, Wang HW, Ahmad M. Enhanced expression of epithelial sodium channels causes salt-induced hypertension in mice through inhibition of the α2-isoform of Na+, K+-ATPase. Physiol Rep 2015; 3:3/5/e12383. [PMID: 25991719 PMCID: PMC4463818 DOI: 10.14814/phy2.12383] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Knockout of the Nedd4-2 gene in mice results in overexpression of epithelial sodium channels (ENaC) on the plasma membrane in the kidney, choroid plexus and brain nuclei. These mice exhibit enhanced pressor responses to CSF [Na(+)] as well as dietary salt-induced hypertension which both can be blocked by central infusion of the ENaC blocker benzamil. Functional studies suggest that ENaC activation in the CNS results in release of endogenous ouabain (EO) and inhibition of the α2-isoform of Na(+), K(+)-ATPase. To test this concept more specifically, we studied Nedd4-2(-/-) mice expressing the ouabain-resistant α2R/R-isoform of Na(+), K(+)-ATPase. Intracerebroventricular (icv) infusion of Na(+)-rich aCSF (225 mmol/L Na(+) at 0.4 μL/min) increased MAP by 10-15 mmHg in wild-type mice and by 25-30 mmHg in Nedd4-2(-/-) mice, but by only ~5 mmHg in α2R/R and in α2R/R/Nedd4-2(-/-) mice. Icv infusion of EO-binding Fab fragments also blocked the BP response in Nedd4-2(-/-) mice. In Nedd4-2(-/-) mice, 8% high-salt diet increased MAP by 25-30 mmHg, but in α2R/R/Nedd4-2(-/-) mice, it increased by only 5-10 mmHg. In contrast, Nedd4-2(-/-) or α2R/R did not affect the hypertension caused by sc infusion of Ang II. These findings substantiate the concept that enhanced ENaC activity causes salt-induced pressor responses mainly through EO inhibiting the α2-isoform of Na(+), K(+)-ATPase in the brain.
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Affiliation(s)
| | - Xiaohong Hou
- University of Ottawa Heart Institute, Ottawa, Ontario, Canada
| | - Hong-Wei Wang
- University of Ottawa Heart Institute, Ottawa, Ontario, Canada
| | - Monir Ahmad
- University of Ottawa Heart Institute, Ottawa, Ontario, Canada
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Kurtz TW, Dominiczak AF, DiCarlo SE, Pravenec M, Morris RC. Molecular-based mechanisms of Mendelian forms of salt-dependent hypertension: questioning the prevailing theory. Hypertension 2015; 65:932-41. [PMID: 25753977 DOI: 10.1161/hypertensionaha.114.05092] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2014] [Accepted: 02/11/2015] [Indexed: 12/20/2022]
Abstract
This critical review directly challenges the prevailing theory that a transient increase in cardiac output caused by genetically mediated increases in activity of the ENaC in the aldosterone sensitive distal nephron, or of the NCC in the distal convoluted tubule, accounts entirely for the hemodynamic initiation of all Mendelian forms of salt-dependent hypertension (Figure 1). The prevailing theory of how genetic mutations enable salt to hemodynamically initiate Mendelian forms of salt-dependent hypertension in humans (Figure 1) depends on the results of salt-loading studies of cardiac output and systemic vascular resistance in nongenetic models of hypertension that lack appropriate normal controls. The theory is inconsistent with the results of studies that include measurements of the initial hemodynamic changes induced by salt loading in normal, salt-resistant controls. The present analysis, which takes into account the results of salt-loading studies that include the requisite normal controls, indicates that mutation-induced increases in the renal tubular activity of ENaC or NCC that lead to transient increases in cardiac output will generally not be sufficient to enable increases in salt intake to initiate the increased BP that characterizes Mendelian forms of salt-dependent hypertension (Table). The present analysis also raises questions about whether mutation-dependent increases in renal tubular activity of ENaC or NCC are even necessary to account for increased risk for salt-dependent hypertension in most patients with such mutations. We propose that for the genetic alterations underlying Mendelian forms of salt-dependent hypertension to enable increases in salt intake to initiate the increased BP, they must often cause vasodysfunction, ie, an inability to normally vasodilate and decrease systemic vascular resistance in response to increases in salt intake within dietary ranges typically observed in most modern societies. A subnormal ability to vasodilate in response to salt loading could be caused by mutation-related disturbances originating in the vasculature itself or in sites outside the vasculature (eg, brain or adrenal glands) that have the capacity to affect vascular function.
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Affiliation(s)
- Theodore W Kurtz
- From the Department of Laboratory Medicine, University of California, San Francisco (T.W.K.); Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, United Kingdom (A.F.D.); Department of Physiology, Wayne State University, Detroit, MI (S.E.D.); Institute of Physiology, Czech Academy of Sciences, Prague, Czech Republic (M.P.); and Department of Medicine, University of California, San Francisco (R.C.M.).
| | - Anna F Dominiczak
- From the Department of Laboratory Medicine, University of California, San Francisco (T.W.K.); Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, United Kingdom (A.F.D.); Department of Physiology, Wayne State University, Detroit, MI (S.E.D.); Institute of Physiology, Czech Academy of Sciences, Prague, Czech Republic (M.P.); and Department of Medicine, University of California, San Francisco (R.C.M.)
| | - Stephen E DiCarlo
- From the Department of Laboratory Medicine, University of California, San Francisco (T.W.K.); Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, United Kingdom (A.F.D.); Department of Physiology, Wayne State University, Detroit, MI (S.E.D.); Institute of Physiology, Czech Academy of Sciences, Prague, Czech Republic (M.P.); and Department of Medicine, University of California, San Francisco (R.C.M.)
| | - Michal Pravenec
- From the Department of Laboratory Medicine, University of California, San Francisco (T.W.K.); Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, United Kingdom (A.F.D.); Department of Physiology, Wayne State University, Detroit, MI (S.E.D.); Institute of Physiology, Czech Academy of Sciences, Prague, Czech Republic (M.P.); and Department of Medicine, University of California, San Francisco (R.C.M.)
| | - R Curtis Morris
- From the Department of Laboratory Medicine, University of California, San Francisco (T.W.K.); Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, United Kingdom (A.F.D.); Department of Physiology, Wayne State University, Detroit, MI (S.E.D.); Institute of Physiology, Czech Academy of Sciences, Prague, Czech Republic (M.P.); and Department of Medicine, University of California, San Francisco (R.C.M.)
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Verouti SN, Boscardin E, Hummler E, Frateschi S. Regulation of blood pressure and renal function by NCC and ENaC: lessons from genetically engineered mice. Curr Opin Pharmacol 2015; 21:60-72. [PMID: 25613995 DOI: 10.1016/j.coph.2014.12.012] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2014] [Revised: 12/22/2014] [Accepted: 12/22/2014] [Indexed: 01/01/2023]
Abstract
The activity of the thiazide-sensitive Na(+)/Cl(-) cotransporter (NCC) and of the amiloride-sensitive epithelial Na(+) channel (ENaC) is pivotal for blood pressure regulation. NCC is responsible for Na(+) reabsorption in the distal convoluted tubule (DCT) of the nephron, while ENaC reabsorbs the filtered Na(+) in the late DCT and in the cortical collecting ducts (CCD) providing the final renal adjustment to Na(+) balance. Here, we aim to highlight the recent advances made using transgenic mouse models towards the understanding of the regulation of NCC and ENaC function relevant to the control of sodium balance and blood pressure. We thus like to pave the way for common mechanisms regulating these two sodium-transporting proteins and their potential implication in structural remodeling of the nephron segments and Na(+) and Cl(-) reabsorption.
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Affiliation(s)
- Sophia N Verouti
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland
| | - Emilie Boscardin
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland
| | - Edith Hummler
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland.
| | - Simona Frateschi
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland.
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Ito K, Hirooka Y, Sunagawa K. Cardiac sympathetic afferent stimulation induces salt-sensitive sympathoexcitation through hypothalamic epithelial Na+ channel activation. Am J Physiol Heart Circ Physiol 2014; 308:H530-9. [PMID: 25527778 DOI: 10.1152/ajpheart.00586.2014] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The cardiac sympathetic afferent (CSA), which plays an important role in heart-brain communication for sympathoexcitation, is stimulated in heart failure. Additionally, high salt intake leads to further sympathoexcitation due to activation of hypothalamic epithelial Na(+) channels (ENaCs) in heart failure. In the present study, we stimulated the CSA in adult male mice by epicardial application of capsaicin and using ethanol as a control to determine whether CSA stimulation led to activation of hypothalamic ENaCs, resulting in salt-induced sympathoexcitation. Three days after capsaicin treatment, an upregulation of hypothalamic α-ENaCs, without activation of mineralocorticoid receptors, was observed. We also examined expression levels of the known ENaC activator TNF-α. Hypothalamic TNF-α increased in capsaicin-treated mice, whereas intracerebroventricular infusion of the TNF-α blocker etanercept prevented capsaicin-induced upregulation of α-ENaCs. To examine brain arterial pressure (AP) sensitivity toward Na(+), we performed an intracerebroventricular infusion of high Na(+)-containing (0.2 M) artificial cerebrospinal fluid. AP and heart rate were significantly increased in capsaicin-treated mice compared with control mice. CSA stimulation also caused excitatory responses with high salt intake. Compared with a regular salt diet, the high-salt diet augmented AP, heart rate, and 24-h urinary norepinephrine excretion, which is an indirect marker of sympathetic activity with mineralocorticoid receptor activation, in capsaicin-treated mice but not in ethanol-treated mice. Treatment with etanercept or the ENaC blocker benzamil prevented these salt-induced excitatory responses. In summary, we show that CSA stimulation leads to an upregulation of hypothalamic α-ENaCs mediated via an increase in TNF-α and results in increased salt sensitivity.
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Affiliation(s)
- Koji Ito
- Department of Cardiovascular Medicine, Kyushu University Graduate School of Medical Sciences, Fukuoka, Japan; and
| | - Yoshitaka Hirooka
- Department of Advanced Cardiovascular Regulation and Therapeutics, Kyushu University Graduate School of Medical Sciences, Fukuoka, Japan
| | - Kenji Sunagawa
- Department of Cardiovascular Medicine, Kyushu University Graduate School of Medical Sciences, Fukuoka, Japan; and
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Fu Y, Vallon V. Mineralocorticoid-induced sodium appetite and renal salt retention: evidence for common signaling and effector mechanisms. Nephron Clin Pract 2014; 128:8-16. [PMID: 25376899 DOI: 10.1159/000368264] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
An increase in renal sodium chloride (salt) retention and an increase in sodium appetite are the body's responses to salt restriction or depletion in order to restore salt balance. Renal salt retention and increased sodium appetite can also be maladaptive and sustain the pathophysiology in conditions like salt-sensitive hypertension and chronic heart failure. Here we review the central role of the mineralocorticoid aldosterone in both the increase in renal salt reabsorption and sodium appetite. We discuss the working hypothesis that aldosterone activates similar signaling and effector mechanisms in the kidney and brain, including the mineralocorticoid receptor, the serum- and glucocorticoid-induced kinase SGK1, the ubiquitin ligase NEDD4-2, and the epithelial sodium channel ENaC. The latter also mediates the gustatory salt sensing in the tongue, which is required for the manifestation of increased salt intake. Effects of aldosterone on both the brain and kidney synergize with the effects of angiotensin II. Thus, mineralocorticoids appear to induce similar molecular pathways in the kidney, brain, and possibly tongue, which could provide opportunities for more effective therapeutic interventions. Inhibition of renal salt reabsorption is compensated by stimulation of salt appetite and vice versa; targeting both mechanisms should be more effective. Inhibiting the arousal to consume salty food may improve a patient's compliance to reducing salt intake. While a better understanding of the molecular mechanisms is needed and will provide new therapeutic options, current pharmacological interventions that target both salt retention and sodium appetite include mineralocorticoid receptor antagonists and potentially inhibitors of angiotensin II and ENaC.
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Affiliation(s)
- Yiling Fu
- Department of Medicine, University of California San Diego, La Jolla, Calif., USA
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