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Saleh MA, Shaaban AA, Talaat IM, Elmougy A, Adra SF, Ahmad F, Qaisar R, Elmoselhi AB, Abu-Gharbieh E, El-Huneidi W, Eladl MA, Shehatou G, Kafl HE. RhoA/ROCK inhibition attenuates endothelin-1-induced elevated glomerular permeability to albumin, inflammation, and fibrosis. Life Sci 2023; 323:121687. [PMID: 37030613 DOI: 10.1016/j.lfs.2023.121687] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Revised: 03/25/2023] [Accepted: 04/05/2023] [Indexed: 04/10/2023]
Abstract
Endothelin-1 (ET-1) contributes to the development of kidney diseases. However, the underlying molecular mechanism is largely undefined. Here we sought to investigate the potential role of ET-1 receptors, ETA and ETB in the regulation of increased glomerular permeability and underlying signaling pathways post-ET-1 infusion. Male Sprague-Dawley rats were infused with ET-1 (2 pmol/kg per minute, i.v.) for four weeks, and the effect on glomerular permeability to albumin (Palb) and albuminuria was measured. The selective ROCK-1/2 inhibitor, Y-27632, was administered to a separate group of rats to determine its effect on ET-1-induced Palb and albuminuria. The role of ETA and ETB receptors in regulating RhoA/ROCK activity was determined by incubating isolated glomeruli from normal rats with ET-1 and with selective ETA and ETB receptor antagonists. ET-1 infusion for four weeks significantly elevated Palb and albuminuria. Y-27632 significantly reduced the elevation of Palb and albuminuria. The activities of both RhoA and ROCK-1/2 were increased by ET-1 infusion. Selective ETB receptor antagonism had no effect on the elevated activity of both RhoA and ROCK-1/2 enzymes. Selective ETA receptor and combined ETA/ETB receptors blockade restored the activity of RhoA and ROCK-1/2 to normal levels. In addition, chronic ET-1 infusion increased the levels of glomerular inflammatory and fibrotic markers. These effects were all attenuated in rats following ROCK-1/2 inhibition. These observations suggest that ET-1 contributes to increased albuminuria, inflammation, and fibrosis by modulating the activity of the ETA-RhoA/ROCK-1/2 pathway. Selective ETA receptor blockade may represent a potential therapeutic strategy to limit glomerular injury and albuminuria in kidney disease.
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Affiliation(s)
- Mohamed A Saleh
- Department of Clinical Sciences, College of Medicine, University of Sharjah, Sharjah 27272, United Arab Emirates; Sharjah Institute for Medical Research, University of Sharjah, Sharjah 27272, United Arab Emirates; Department of Pharmacology and Toxicology, Faculty of Pharmacy, Mansoura University, Mansoura 35516, Egypt.
| | - Ahmed A Shaaban
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Mansoura University, Mansoura 35516, Egypt; Department of Pharmacology and Biochemistry, Faculty of Pharmacy, Delta University for Science and Technology, Gamasa City 35712, Egypt
| | - Iman M Talaat
- Department of Clinical Sciences, College of Medicine, University of Sharjah, Sharjah 27272, United Arab Emirates; Sharjah Institute for Medical Research, University of Sharjah, Sharjah 27272, United Arab Emirates; Pathology Department, Faculty of Medicine, Alexandria University, Alexandria 21526, Egypt
| | - Atef Elmougy
- Pediatric Nephrology Unit, Mansoura University Children's Hospital, Mansoura University, Mansoura 35516, Egypt
| | - Saryia F Adra
- Department of Clinical Sciences, College of Medicine, University of Sharjah, Sharjah 27272, United Arab Emirates
| | - Firdos Ahmad
- Department of Basic Medical Sciences, College of Medicine, University of Sharjah, Sharjah 27272, United Arab Emirates; Department of Biomedical Sciences, College of Health Sciences, Abu Dhabi University, Abu Dhabi 59911, United Arab Emirates
| | - Rizwan Qaisar
- Department of Basic Medical Sciences, College of Medicine, University of Sharjah, Sharjah 27272, United Arab Emirates
| | - Adel B Elmoselhi
- Department of Basic Medical Sciences, College of Medicine, University of Sharjah, Sharjah 27272, United Arab Emirates
| | - Eman Abu-Gharbieh
- Department of Clinical Sciences, College of Medicine, University of Sharjah, Sharjah 27272, United Arab Emirates; Sharjah Institute for Medical Research, University of Sharjah, Sharjah 27272, United Arab Emirates
| | - Waseem El-Huneidi
- Sharjah Institute for Medical Research, University of Sharjah, Sharjah 27272, United Arab Emirates; Department of Basic Medical Sciences, College of Medicine, University of Sharjah, Sharjah 27272, United Arab Emirates
| | - Mohamed A Eladl
- Department of Basic Medical Sciences, College of Medicine, University of Sharjah, Sharjah 27272, United Arab Emirates
| | - George Shehatou
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Mansoura University, Mansoura 35516, Egypt; Department of Pharmacology and Biochemistry, Faculty of Pharmacy, Delta University for Science and Technology, Gamasa City 35712, Egypt
| | - Hoda E Kafl
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Mansoura University, Mansoura 35516, Egypt
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Influence of Trace Elements on Neurodegenerative Diseases of The Eye-The Glaucoma Model. Int J Mol Sci 2021; 22:ijms22094323. [PMID: 33919241 PMCID: PMC8122456 DOI: 10.3390/ijms22094323] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Revised: 04/16/2021] [Accepted: 04/18/2021] [Indexed: 02/07/2023] Open
Abstract
Glaucoma is a heterogeneous group of chronic neurodegenerative disorders characterized by a relatively selective, progressive damage to the retinal ganglion cells (RGCs) and their axons, which leads to axon loss and visual field alterations. To date, many studies have shown the role of various elements, mainly metals, in maintaining the balance of prooxidative and antioxidative processes, regulation of fluid and ion flow through cell membranes of the ocular tissues. Based on the earlier and current research results, their relationship with the development and progression of glaucoma seems obvious and is increasingly appreciated. In this review, we aimed to summarize the current evidence on the role of trace elements in the pathogenesis and prevention of glaucomatous diseases. Special attention is also paid to the genetic background associated with glaucoma-related abnormalities of physiological processes that regulate or involve the ions of elements considered as trace elements necessary for the functioning of the cells.
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Inhibition of microRNA-429 in the renal medulla increased salt sensitivity of blood pressure in Sprague Dawley rats. J Hypertens 2018; 35:1872-1880. [PMID: 28445205 DOI: 10.1097/hjh.0000000000001373] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
BACKGROUND We have previously shown that high salt intake suppresses the expression of prolyl hydroxylase domain-containing protein 2 (PHD2), an enzyme promoting the degradation of hypoxia-inducible factor (HIF)-1α, and increases HIF-1α along with its target genes in the renal medulla, which promotes sodium excretion and regulates salt sensitivity of blood pressure. However, it remains unknown how high salt inhibits the expression of PHD2. METHOD AND RESULTS The current study first revealed that high-salt-induced PHD2 inhibition was due to the enhanced decay of mRNA. We then found that high salt significantly increased the expression of miR-429, which was subsequently proven to target the 3'-untranslated region of PHD2 and reduce PHD2 levels, in the renal medulla. To define the functional role of renal medullary miR-429 in the regulation of PHD2/HIF-1α-mediated renal adaptation to high salt intake and salt sensitivity of blood pressure, we locally inhibited miR-429 in the renal medulla by locked nucleic acid anti-miR-429 in uninephrectomized rats. Our results demonstrated that inhibition of miR-429 remarkably increased the levels of PHD2, which disrupted PHD2-associated adaptive activation of HIF-1α-mediated gene expression in response to high salt in the renal medulla and consequently inhibited urinary sodium excretion, enhanced sodium retention in response to chronic sodium overloading, and as a result, produced a salt-sensitive hypertension. CONCLUSION It is concluded that miR-429 is an important upstream mediator in PHD2/HIF-1α-associated renal adaptation to high salt intake and that deficiency in miR-429-mediated PHD2 inhibition in response to high salt in the renal medulla may represent a pathogenic mechanism for salt-sensitive hypertension.
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Endothelin-1, α-Klotho, 25(OH) Vit D levels and severity of disease in scleroderma patients. Rheumatol Int 2017; 37:1651-1657. [PMID: 28831601 DOI: 10.1007/s00296-017-3797-z] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Accepted: 08/17/2017] [Indexed: 10/19/2022]
Abstract
Considering the role of endothelin-1 (ET-1) in tissue remodeling and fibrosis during the development of scleroderma as well as the effect of α-Klotho in pathogenesis of calcinosis and/or endothelial cell injury and its correlation with severity of disease, this study aimed to evaluate serum ET-1, α-Klotho and 25(OH) vitamin D levels in patients with limited and diffuse scleroderma compared to healthy subjects. In this cross-sectional study, 60 scleroderma patients according to the ACR/EULAR 2013 criteria and 60 age- and sex-matched healthy controls were included. In patients, clinical examination was performed and Medsger severity scale was assessed. Serum ET-1, soluble α-Klotho and 25(OH)D3 levels were measured using ELISA kits. The mean ± SD age of patients and controls was 46.2 ± 9.6 and 47.2 ± 7.0 years, respectively. Compared to healthy controls, serum ET-1 was significantly higher in SSc patients (p = 0.001); whilst serum α-Klotho and 25(OH)D3 were significantly lower in patients (p = 0.001). The most common organs involved in patients were skin, lung, peripheral vascular and gastrointestinal system and the severity of involvement was mainly mild and/or moderate. There were no significant differences in serum ET-1 and α-Klotho levels according to the severity of different organ involvement (p > 0.05). There was no significant correlation between presence or absence of calcinosis and negative or positivity of auto-antibodies with ET-1, α-Klotho and 25(OH)D3 levels. Although our study revealed higher serum ET-1 and lower serum α-Klotho levels in SSc patients compared to healthy controls, there were not any significant correlations between their serum levels with severity of organ involvement.
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Azzam ZS, Kinaneh S, Bahouth F, Ismael-Badarneh R, Khoury E, Abassi Z. Involvement of Cytokines in the Pathogenesis of Salt and Water Imbalance in Congestive Heart Failure. Front Immunol 2017; 8:716. [PMID: 28674538 PMCID: PMC5474564 DOI: 10.3389/fimmu.2017.00716] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Accepted: 06/02/2017] [Indexed: 12/28/2022] Open
Abstract
Congestive heart failure (CHF) has become a major medical problem in the western world with high morbidity and mortality rates. CHF adversely affects several systems, mainly the kidneys and the lungs. While the involvement of the renin-angiotensin-aldosterone system and the sympathetic nervous system in the progression of cardiovascular, pulmonary, and renal dysfunction in experimental and clinical CHF is well established, the importance of pro-inflammatory mediators in the pathogenesis of this clinical setting is still evolving. In this context, CHF is associated with overexpression of pro-inflammatory cytokines, such as tumor necrosis factor-α, interleukin (IL)-1, and IL-6, which are activated in response to environmental injury. This family of cytokines has been implicated in the deterioration of CHF, where it plays an important role in initiating and integrating homeostatic responses both at the myocardium and circulatory levels. We and others showed that angiotensin II decreased the ability of the lungs to clear edema and enhanced the fibrosis process via phosphorylation of the mitogen-activated protein kinases p38 and p42/44, which are generally involved in cellular responses to pro-inflammatory cytokines. Literature data also indicate the involvement of these effectors in modulating ion channel activity. It has been reported that in heart failure due to mitral stenosis; there were varying degrees of vascular and other associated parenchymal changes such as edema and fibrosis. In this review, we will discuss the effects of cytokines and other inflammatory mediators on the kidneys and the lungs in heart failure; especially their role in renal and alveolar ion channels activity and fluid balance.
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Affiliation(s)
- Zaher S. Azzam
- Department of Physiology and Biophysics, Technion, Israel Institute of Technology, Haifa, Israel
- Internal Medicine “B”, Rambam Health Care Campus, Haifa, Israel
| | - Safa Kinaneh
- Department of Physiology and Biophysics, Technion, Israel Institute of Technology, Haifa, Israel
| | - Fadel Bahouth
- Department of Physiology and Biophysics, Technion, Israel Institute of Technology, Haifa, Israel
| | - Reem Ismael-Badarneh
- Department of Physiology and Biophysics, Technion, Israel Institute of Technology, Haifa, Israel
| | - Emad Khoury
- Department of Physiology and Biophysics, Technion, Israel Institute of Technology, Haifa, Israel
| | - Zaid Abassi
- Department of Physiology and Biophysics, Technion, Israel Institute of Technology, Haifa, Israel
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Fellner RC, Guan Z, Cook AK, Pollock DM, Inscho EW. Endothelin contributes to blunted renal autoregulation observed with a high-salt diet. Am J Physiol Renal Physiol 2015; 309:F687-96. [PMID: 26246513 DOI: 10.1152/ajprenal.00641.2014] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Accepted: 07/29/2015] [Indexed: 01/03/2023] Open
Abstract
Autoregulation of renal blood flow (RBF) is an essential function of the renal microcirculation that has been previously shown to be blunted by excessive dietary salt. Endogenous endothelin 1 (ET-1) is increased following a high-salt (HS) diet and contributes to the control of RBF but the differential effects of ET-1 on renal microvessel autoregulation in response to HS remain to be established. We hypothesized that a HS diet increases endothelin receptor activation in normal Sprague-Dawley rats and blunts autoregulation of RBF. The role of ET-1 in the blunted autoregulation produced by a HS diet was assessed in vitro and in vivo using the blood-perfused juxtamedullary nephron preparation and anesthetized rats, respectively. Using highly selective antagonists, we observed that blockade of either ETA or ETB receptors was sufficient to restore normal autoregulatory behavior in afferent arterioles from HS-fed rats. Additionally, normal autoregulatory behavior was restored in vivo in HS-fed rats by simultaneous ETA and ETB receptor blockade, whereas blockade of ETB receptors alone showed significant improvement of normal autoregulation of RBF. Consistent with this observation, autoregulation of RBF in ETB receptor-deficient rats fed HS was similar to both ETB-deficient rats and transgenic control rats on normal-salt diets. These data support the hypothesis that endogenous ET-1, working through ETB and possibly ETA receptors, contributes to the blunted renal autoregulatory behavior in rats fed a HS diet.
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Affiliation(s)
- Robert C Fellner
- Department of Physiology, Medical College of Georgia, Georgia Regents University, Augusta, Georgia
| | - Zhengrong Guan
- Department of Physiology, Medical College of Georgia, Georgia Regents University, Augusta, Georgia; Division of Nephrology, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama
| | - Anthony K Cook
- Department of Physiology, Medical College of Georgia, Georgia Regents University, Augusta, Georgia; Division of Nephrology, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama
| | - David M Pollock
- Section of Experimental Medicine, Department of Medicine, Medical College of Georgia, Georgia Regents University, Augusta, Georgia; and Division of Nephrology, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama
| | - Edward W Inscho
- Department of Physiology, Medical College of Georgia, Georgia Regents University, Augusta, Georgia; Division of Nephrology, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama
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Natarajan AR, Eisner GM, Armando I, Browning S, Pezzullo JC, Rhee L, Dajani M, Carey RM, Jose PA. The Renin-Angiotensin and Renal Dopaminergic Systems Interact in Normotensive Humans. J Am Soc Nephrol 2015; 27:265-79. [PMID: 25977313 DOI: 10.1681/asn.2014100958] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2014] [Accepted: 03/26/2015] [Indexed: 12/22/2022] Open
Abstract
The renin-angiotensin-aldosterone (RAAS) and renal dopaminergic systems interact to maintain sodium balance. High NaCl intake increases renal synthesis of dopamine and dopaminergic receptor activity, decreasing epithelial sodium transport, whereas sodium deficit activates the RAAS, increasing epithelial sodium transport. We tested the hypothesis that attenuation of the natriuretic effect of dopamine D1-like receptors during salt restriction results in part from increased RAAS activity in seven salt-resistant normotensive adults using a double-blind placebo-controlled balanced crossover design. All subjects attained sodium balance on low (50 mmol Na(+)/day) and high (300 mmol Na(+)/day) NaCl diets, administered 4 weeks apart. Sodium, potassium, lithium, para-aminohippurate, and creatinine clearances were measured before, during, and after a 3-hour infusion of fenoldopam, a D1-like receptor agonist, with and without pretreatment with enalapril, an angiotensin converting enzyme inhibitor. On the high NaCl diet, fenoldopam-induced natriuresis was associated with the inhibition of renal proximal and distal tubule sodium transport. On the low NaCl diet, fenoldopam decreased renal distal tubule sodium transport but did not cause natriuresis. The addition of enalapril to fenoldopam restored the natriuretic effect of fenoldopam and its inhibitory effect on proximal tubule sodium transport. Thus, on a high NaCl diet fenoldopam causes natriuresis by inhibiting renal proximal and distal tubule transport, but on a low NaCl diet the increased RAAS activity prevents the D1-like receptor from inhibiting renal proximal tubule sodium transport, neutralizing the natriuretic effect of fenoldopam. These results demonstrate an interaction between the renin-angiotensin and renal dopaminergic systems in humans and highlight the influence of dietary NaCl on these interactions.
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Affiliation(s)
| | - Gilbert M Eisner
- Internal Medicine, MedStar-Georgetown University Hospital, Washington, DC
| | - Ines Armando
- Department of Medicine, Division of Nephrology, and
| | - Shaunagh Browning
- Clinical Research Unit, Georgetown University Medical Center, Washington, DC; and
| | - John C Pezzullo
- Clinical Research Unit, Georgetown University Medical Center, Washington, DC; and
| | - Lauren Rhee
- Clinical Research Unit, Georgetown University Medical Center, Washington, DC; and
| | | | - Robert M Carey
- Department of Internal Medicine, The University of Virginia, Charlottesville, Virginia
| | - Pedro A Jose
- Department of Medicine, Division of Nephrology, and Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland
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Wang Y, Sun Z. Antiaging gene Klotho regulates endothelin-1 levels and endothelin receptor subtype B expression in kidneys of spontaneously hypertensive rats. J Hypertens 2015; 32:1629-36; discussion 1636. [PMID: 24979306 DOI: 10.1097/hjh.0000000000000233] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
OBJECTIVE Klotho is an antiaging gene and is predominately expressed in kidneys. The endothelin system is critical in the regulation of kidney function. The objective of this study is to assess whether klotho affects the renal endothelin system in spontaneously hypertensive rats (SHRs). METHOD Four groups of male SHRs and one group of male Wistar-Kyoto (WKY) rats were used. In-vivo expression of klotho was achieved by AAV2 delivery of mouse klotho full-length cDNA (AAV.mKL). Four groups of SHRs were given (intravenously) AAV.mKL, AAV.LacZ, AAV.GFP, and phosphate-buffered saline, respectively. The WKY group was given phosphate-buffered saline and served as a control. At the end of week 12 after gene delivery, all animals were euthanized. RESULTS Plasma endothelin-1 (ET-1) and renal ET-1 levels were increased in SHRs vs. WKY rats. In-vivo expression of klotho reversed the elevated ET-1 levels in SHRs. ETB receptor protein expression was decreased in both kidney cortex and medulla of SHRs. Interestingly, in-vivo expression of klotho abolished the downregulation of ETB protein expression in SHRs, suggesting that klotho regulates ETB receptor expression. Klotho gene delivery also eliminated the increase in the ratio of ETA/ETB in SHRs. Mitochondrial superoxide dismutase (Mn-SOD) protein expression was decreased in kidneys of SHRs, which was rescued by in-vivo expression of klotho. CONCLUSION Klotho gene delivery abolished the upregulation of ET-1 levels and the downregulation of ETB and Mn-SOD expression in kidneys of SHRs. These findings revealed a previously unidentified role of klotho in the regulation of the renal ET system and Mn-SOD in SHRs.
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Affiliation(s)
- Yuhong Wang
- Department of Physiology, College of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
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Speed JS, D'Angelo G, Wach PA, Sullivan JC, Pollock JS, Pollock DM. High salt diet increases the pressor response to stress in female, but not male ETB-receptor-deficient rats. Physiol Rep 2015; 3:3/3/e12326. [PMID: 25802361 PMCID: PMC4393160 DOI: 10.14814/phy2.12326] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Acute stress in both rodents and humans causes a transient rise in blood pressure associated with an increase in plasma endothelin-1 (ET-1). High salt (HS) intake also increases ET-1 production, and interestingly, blunts the pressor response to acute air jet stress in rats. We previously reported that female rats lacking functional ETB receptors everywhere except sympathetic nerves (ETB def) had a greater degree of hypertension in response to a HS diet compared to their male counterparts when measured by the tail cuff method. However, we now report that salt-induced hypertension is not different between sexes when measured by telemetry. Therefore, additional experiments were designed to test the hypothesis that female ETB def rats are more sensitive to acute stress when on a HS diet. The pressor response, measured by telemetry, to acute air jet stress was similar between male transgenic control (Tg control) and ETB def rats following chronic HS intake. In contrast, female ETB def rats had a significantly greater pressor response (about twofold higher) than female or male Tg control or male ETB def rats maintained on HS, a finding that cannot be explained by increased vascular reactivity to ET-1 in female rats as we observed that male ETB def rats had a greater pressor response to i.v. infusion of ET-1 compared to females. Furthermore, HS feeding exacerbated the pressor response to ET-1 in both male and female ETB def rats. Given our previous studies demonstrating that the ETA receptor functions to reduce the pressor response to acute stress, these findings further support a role for the ET receptor system in the pressor response to acute stress and that female rats have reduced ETA receptor activity when on a HS diet compared to males.
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Affiliation(s)
- Joshua S Speed
- Division of Nephrology, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Gerard D'Angelo
- Division of Nephrology, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Paul A Wach
- Division of Nephrology, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Jennifer C Sullivan
- Division of Nephrology, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Jennifer S Pollock
- Division of Nephrology, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - David M Pollock
- Division of Nephrology, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA
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Khamaisi M, Toukan H, Axelrod JH, Rosenberger C, Skarzinski G, Shina A, Meidan R, Koesters R, Rosen S, Walkinshaw G, Mimura I, Nangaku M, Heyman SN. Endothelin-converting enzyme is a plausible target gene for hypoxia-inducible factor. Kidney Int 2014; 87:761-70. [PMID: 25469848 DOI: 10.1038/ki.2014.362] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2014] [Revised: 09/05/2014] [Accepted: 09/11/2014] [Indexed: 11/09/2022]
Abstract
Renal endothelin-converting enzyme (ECE)-1 is induced in experimental diabetes and following radiocontrast administration, conditions characterized by renal hypoxia, hypoxia-inducible factor (HIF) stabilization, and enhanced endothelin synthesis. Here we tested whether ECE-1 might be a HIF-target gene in vitro and in vivo. ECE-1 transcription and expression increased in cultured vascular endothelial and proximal tubular cell lines, subject to hypoxia, to mimosine or cobalt chloride. These interventions are known to stabilize HIF signaling by inhibition of HIF-prolyl hydroxylases. In rats, HIF-prolyl-hydroxylase inhibition by mimosine or FG-4497 increased HIF-1α immunostaining in renal tubules, principally in distal nephron segments. This was associated with markedly enhanced ECE-1 protein expression, predominantly in the renal medulla. A progressive and dramatic increase in ECE-1 immunostaining over time, in parallel with enhanced HIF expression, was also noted in conditional von Hippel-Lindau knockout mice. Since HIF and STAT3 are cross-stimulated, we triggered HIF expression by STAT3 activation in mice, transfected by or injected with a chimeric IL-6/IL-6-receptor protein, and found a similar pattern of enhanced ECE-1 expression. Chromatin immunoprecipitation sequence (ChIP-seq) and PCR analysis in hypoxic endothelial cells identified HIF binding at the ECE-1 promoter and intron regions. Thus, our findings suggest that ECE-1 may be a novel HIF-target gene.
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Affiliation(s)
- Mogher Khamaisi
- Institute of Endocrinology, Diabetes & Metabolism, Rambam Medical Center & RB Rappaport Faculty of Medicine-Technion, Haifa, Israel
| | - Hala Toukan
- Institute of Endocrinology, Diabetes & Metabolism, Rambam Medical Center & RB Rappaport Faculty of Medicine-Technion, Haifa, Israel
| | - Jonathan H Axelrod
- Goldyne Savad Institute of Gene Therapy, Hebrew University, Hadassah Hospitals, Jerusalem, Israel
| | | | - Galia Skarzinski
- Department of Medicine, Hebrew University, Hadassah Hospitals, Jerusalem, Israel
| | - Ahuva Shina
- Department of Medicine, Hebrew University, Hadassah Hospitals, Jerusalem, Israel
| | - Rina Meidan
- Department of Animal Sciences, The Robert H Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Robert Koesters
- Department of Nephrology, Tenon Hospital, University Pierre et Marie Curie, Paris, France
| | - Seymour Rosen
- Department of Pathology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA
| | | | - Imari Mimura
- Divisions of Nephrology and Endocrinology, University of Tokyo School of Medicine, Tokyo, Japan
| | - Masaomi Nangaku
- Divisions of Nephrology and Endocrinology, University of Tokyo School of Medicine, Tokyo, Japan
| | - Samuel N Heyman
- Department of Medicine, Hebrew University, Hadassah Hospitals, Jerusalem, Israel
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Brochu I, Houde M, Desbiens L, Simard E, Gobeil F, Semaan W, Bkaily G, D'Orléans-Juste P. High salt-induced hypertension in B2 knockout mice is corrected by the ETA antagonist, A127722. Br J Pharmacol 2014; 170:266-77. [PMID: 23713522 DOI: 10.1111/bph.12259] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2012] [Revised: 05/12/2013] [Accepted: 05/17/2013] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND AND PURPOSE The contribution of endothelin-1 (ET-1) in a B2KO mouse model of a high salt-induced arterial hypertension was investigated. EXPERIMENTAL APPROACH Wild-type (WT) or B2KO mice receiving a normal diet (ND) or a high-salt diet (HSD) were monitored by radiotelemetry up to a maximum of 18 weeks. At the 12th week of diet, subgroups under ND or HSD received by gavage the ETA antagonist A127722 during 5 days. In addition, blood samples were collected and, following euthanasia, the lungs, heart and kidneys were extracted, homogenized and assayed for ET-1 by RIA. In a separate series of experiments, the ETA antagonist, BQ123 was tested against the pressor responses to a NOS inhibitor L-N(G)-nitroarginine methyl ester (L-NAME) in anaesthetized WT and B2KO mice. KEY RESULTS In B2KO, but not WT mice, 12 weeks of HSD triggered a maximal increase of the mean arterial pressure (MAP) of 19.1 ± 2.8 mmHg, which was corrected by A127722 to MAP levels found in B2KO mice under ND. Significant increases in immunoreactive ET-1 were detected only in the lungs of B2KO mice under HSD. On the other hand, metabolic studies showed that sodium urinary excretion was markedly reduced in B2KO compared with WT mice under ND. Finally, BQ123 (2 mg·kg(-1)) reduced by 50% the pressor response to L-NAME (2 mg·kg(-1)) in B2KO, but not WT mice under anaesthesia. CONCLUSIONS AND IMPLICATIONS Our results support the concept that functional B2 receptors oppose high salt-induced increments in MAP, which are corrected by an ETA receptor antagonist in this mouse model of experimental hypertension.
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Affiliation(s)
- I Brochu
- Department of Pharmacology, Medical School, Université de Sherbrooke, Sherbrooke, QC, Canada
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Guh YJ, Tseng YC, Yang CY, Hwang PP. Endothelin-1 regulates H⁺-ATPase-dependent transepithelial H⁺ secretion in zebrafish. Endocrinology 2014; 155:1728-37. [PMID: 24424055 DOI: 10.1210/en.2013-1775] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Endothelin-1 (EDN1) is an important regulator of H⁺ secretion in the mammalian kidney. EDN1 enhances renal tubule H⁺-ATPase activity, but the underlying mechanism remains unclear. To further elucidate the role of EDN1 in vertebrates' acid-base regulation, the present study used zebrafish as the model to examine the effects of EDN1 and its receptors on transepithelial H⁺ secretion. Expression of EDN1 and one of its receptors, EDNRAa, was stimulated in zebrafish acclimated to acidic water. A noninvasive scanning ion-selective electrode technique was used to show that edn1 overexpression enhances H⁺ secretion in embryonic skin at 3 days post fertilization. EDNRAa loss of function significantly decreased EDN1- and acid-induced H⁺ secretion. Abrogation of EDN1-enhanced H⁺ secretion by a vacuolar H⁺-ATPase inhibitor (bafilomycin A1) suggests that EDN1 exerts its action by regulating the H⁺-ATPase-mediated H⁺ secretion. EDN1 does not appear to affect H⁺ secretion through either altering the abundance of H⁺-ATPase or affecting the cell differentiation of H⁺-ATPase-rich ionocytes, because the reduction in secretion upon ednraa knockdown was not accompanied by decreased expression of H⁺-ATPase or reduced H⁺-ATPase-rich cell density. These findings provide evidence that EDN1 signaling is involved in acid-base regulation in zebrafish and enhance our understanding of EDN1 regulation of transepithelial H⁺ secretion in vertebrates.
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Affiliation(s)
- Ying-Jey Guh
- Graduate Institute of Life Sciences (Y.-J.G., P.-P.H.), National Defense Medical Center, Taipei, Taiwan; Institute of Cellular and Organismic Biology (Y.-J.G., C.-Y.Y., P.-P.H.), Academia Sinica, Taipei, Taiwan; Department of Life Science (Y.-C.T.), National Taiwan Normal University and Institute of Fisheries Science (C.-Y.Y.), National Taiwan University, Taipei, Taiwan
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Zhu Q, Hu J, Han WQ, Zhang F, Li PL, Wang Z, Li N. Silencing of HIF prolyl-hydroxylase 2 gene in the renal medulla attenuates salt-sensitive hypertension in Dahl S rats. Am J Hypertens 2014; 27:107-13. [PMID: 24190904 DOI: 10.1093/ajh/hpt207] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND In response to high salt intake, transcription factor hypoxia-inducible factor (HIF) 1α activates many antihypertensive genes, such as heme oxygenase 1 (HO-1) 1 and cyclooxygenase 2 (COX-2) in the renal medulla, which is an important molecular adaptation to promote extra sodium excretion. We recently showed that high salt inhibited the expression of HIF prolyl-hydroxylase 2 (PHD2), an enzyme that promotes the degradation of HIF-1α, thereby upregulating HIF-1α, and that high salt-induced inhibition in PHD2 and subsequent activation of HIF-1α in the renal medulla was blunted in Dahl salt-sensitive hypertensive rats. This study tested the hypothesis that silencing the PHD2 gene to increase HIF-1α levels in the renal medulla attenuates salt-sensitive hypertension in Dahl S rats. METHODS PHD2 short hairpin RNA (shRNA) plasmids were transfected into the renal medulla in uninephrectomized Dahl S rats. Renal function and blood pressure were then measured. RESULTS PHD2 shRNA reduced PHD2 levels by >60% and significantly increased HIF-1α protein levels and the expression of HIF-1α target genes HO-1 and COX-2 by >3-fold in the renal medulla. Functionally, pressure natriuresis was remarkably enhanced, urinary sodium excretion was doubled after acute intravenous sodium loading, and chronic high salt-induced sodium retention was remarkably decreased, and as a result, salt-sensitive hypertension was significantly attenuated in PHD2 shRNA rats compared with control rats. CONCLUSIONS Impaired PHD2 response to high salt intake in the renal medulla may represent a novel mechanism for hypertension in Dahl S rats, and inhibition of PHD2 in the renal medulla could be a therapeutic approach for salt-sensitive hypertension.
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Affiliation(s)
- Qing Zhu
- Department of Pharmacology & Toxicology, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, VA
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Lynch IJ, Welch AK, Kohan DE, Cain BD, Wingo CS. Endothelin-1 inhibits sodium reabsorption by ET(A) and ET(B) receptors in the mouse cortical collecting duct. Am J Physiol Renal Physiol 2013; 305:F568-73. [PMID: 23698114 DOI: 10.1152/ajprenal.00613.2012] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The collecting duct (CD) is a major renal site for the hormonal regulation of Na homeostasis and is critical for systemic arterial blood pressure control. Our previous studies demonstrated that the endothelin-1 gene (edn1) is an early response gene to the action of aldosterone. Because aldosterone and endothelin-1 (ET-1) have opposing actions on Na reabsorption (JNa) in the kidney, we postulated that stimulation of ET-1 by aldosterone acts as a negative feedback mechanism, acting locally within the CD. Aldosterone is known to increase JNa in the CD, in part, by stimulating the epithelial Na channel (ENaC). In contrast, ET-1 increases Na and water excretion through its binding to receptors in the CD. To date, direct measurement of the quantitative effect of ET-1 on transepithelial JNa in the isolated in vitro microperfused mouse CD has not been determined. We observed that the CD exhibits substantial JNa in male and female mice that is regulated, in part, by a benzamil-sensitive pathway, presumably ENaC. ENaC-mediated JNa is greater in the cortical CD (CCD) than in the outer medullary CD (OMCD); however, benzamil-insensitive JNa is present in the CCD and not in the OMCD. In the presence of ET-1, ENaC-mediated JNa is significantly inhibited. Blockade of either ETA or ETB receptor restored JNa to control rates; however, only ETA receptor blockade restored a benzamil-sensitive component of JNa. We conclude 1) Na reabsorption is mediated by ENaC in the CCD and OMCD and also by an ENaC-independent mechanism in the CCD; and 2) ET-1 inhibits JNa in the CCD through both ETA and ETB receptor-mediated pathways.
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Affiliation(s)
- I Jeanette Lynch
- Research Service, North Florida/South Georgia Veterans Health System, 1601 SW Archer Road, Gainesville, FL 32608.
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Fox B, Langleben D, Hirsch AM, Schlesinger RD, Eisenberg MJ, Joyal D, Blenkhorn F, Lesenko L. Hemodynamic stability after transitioning between endothelin receptor antagonists in patients with pulmonary arterial hypertension. Can J Cardiol 2012; 29:672-7. [PMID: 22819360 DOI: 10.1016/j.cjca.2012.05.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2012] [Revised: 05/09/2012] [Accepted: 05/23/2012] [Indexed: 10/28/2022] Open
Abstract
BACKGROUND Maintenance of a favourable hemodynamic profile is central to therapeutic success in pulmonary arterial hypertension (PAH). There is little information about the safety of transitioning patients between oral therapies for PAH. Endothelin receptor antagonists (ERAs) have been a therapeutic mainstay in PAH, providing benefit to many patients. Three ERAs, bosentan, sitaxsentan, and ambrisentan have been approved for clinical use. Sitaxsentan was voluntarily withdrawn from the market in late 2010 resulting in the need to quickly transition a large number of stable patients. METHODS We transitioned 30 clinically stable patients to either ambrisentan or bosentan. Patients underwent a right heart catheterization, measurement of serum N-terminal pro-brain natriuretic peptide (NT-proBNP), and assessment of functional class before changing ERA and again 4 months later. We present a retrospective analysis of those data. RESULTS Of the 30 patients transitioned (15 to ambrisentan, 15 to bosentan), 23 had complete hemodynamic data. No significant change was observed in the groups in right atrial, mean pulmonary artery, and pulmonary artery wedge pressures, or in cardiac output, pulmonary vascular resistance, or NT-proBNP levels. There was no change in World Health Organization functional class. Four ambrisentan and 2 bosentan-treated patients reported fluid retention, and 3 bosentan-treated patients had elevation of hepatic transaminases. Two of the patients had a right atrial pressure increase of ≥5 mm Hg, and 4 had pulmonary artery wedge pressure increase of ≥5 mm Hg. CONCLUSIONS Transitioning between ERAs in stable PAH patients does not result in hemodynamic or clinical deterioration during the first 4 months posttransition. A minority of patients have developed increased cardiac filling pressures.
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Affiliation(s)
- Benjamin Fox
- Center for Pulmonary Vascular Disease, Jewish General Hospital and McGill University, Montreal, Québec, Canada
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Abstract
Despite its apparently simple molecular aetiology, sickle cell disease (SCD) has long been known to have a remarkably variable clinical course, with complications involving many organs including the kidneys. Whilst many affected individuals show no evidence of renal involvement into late adulthood, others develop renal dysfunction in childhood or early adult life with a significant proportion eventually requiring renal replacement therapy. This review explores the pathophysiology and clinical manifestations of sickle cell nephropathy (SCN) and discusses how each complication can be investigated, monitored and managed in the outpatient setting. We summarize current knowledge of genetic modulation of sickle-related renal dysfunction. We outline the evidence for various treatment options and discuss others for which little evidence currently exists.
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