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Majid DSA, Castillo A, Prieto MC, Navar LG. High salt induced augmentation of angiotensin II mediated hypertension is associated with differential expression of tumor necrosis factor-alpha receptors in the kidney. EXPLORATION OF MEDICINE 2022. [DOI: 10.37349/emed.2022.00086] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Aim: Chronic high salt (HS) intake causes minimal changes in blood pressure (BP) but it induces augmented hypertensive response to angiotensin II (AngII) administration in rodents. The mechanism of this augmentation is not clearly understood. As tumor necrosis factor-alpha (TNF-α) induces natriuresis by activating TNF-α receptor type 1 (TNFR1) but not type 2 (TNFR2), we hypothesize that TNFR1 activity is reduced when HS is given in combination of AngII that leads to enhanced sodium retention and thus, causing augmented hypertension. The aim of this study is to examine the responses to chronic HS intake and AngII administration on the renal tissue protein expressions of TNFR1 and TNFR2 in mice.
Methods: Different groups of mice (n = 6–7 in each group) chronically treated with or without AngII (25 ng/min; implanted minipump) for 4 weeks which were fed either normal salt (NS; 0.4% NaCl) or high salt (HS; 4% NaCl) diets. Systemic BP was measured by tail-cuff plethysmography. At the end of treatment period, kidneys were harvested after sacrificing the mice with euthanasia. Immuno-histochemical analysis of TNFR1 and TNFR2 proteins in renal tissues was performed by measuring the staining area and the intensity of receptors’ immunoreactivities using NIS-Elements software. The results were expressed in percent area of positive staining and the relative intensity.
Results: HS intake alone did not alter mean BP (HS; 77 ± 1 vs. NS; 76 ± 3 vs. mmHg; tail-cuff plethysmography) but AngII induced increases in BP were augmented in HS group (104 ± 2 vs. 95 ± 2 mmHg; P < 0.05). The area of TNFR1 staining was higher in HS than NS group (6.0 ± 0.9% vs. 3.2 ± 0.7%; P < 0.05) but it was lower in AngII + HS than in AngII + NS group (5.0 ± 0.7% vs. 6.3 ± 0.7%; P = 0.068). TNFR2 immunoreactivity was minimal in NS and HS groups but it was high in AngII + NS and even higher in AngII + HS group.
Conclusions: These data suggest that the HS induced increased TNFR1 activity that facilitates enhanced sodium excretion is compromised in elevated AngII condition leading to salt retention and augmented hypertension.
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Affiliation(s)
- Dewan S. A. Majid
- Department of Physiology, Hypertension and Renal Center of Excellence, Tulane University School of Medicine, New Orleans, LA 70112, USA
| | - Alexander Castillo
- Department of Physiology, Hypertension and Renal Center of Excellence, Tulane University School of Medicine, New Orleans, LA 70112, USA
| | - Minolfa C. Prieto
- Department of Physiology, Hypertension and Renal Center of Excellence, Tulane University School of Medicine, New Orleans, LA 70112, USA
| | - L. Gabriel Navar
- Department of Physiology, Hypertension and Renal Center of Excellence, Tulane University School of Medicine, New Orleans, LA 70112, USA
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Lee H, Jiang X, Perwaiz I, Yu P, Wang J, Wang Y, Hüttemann M, Felder RA, Sibley DR, Polster BM, Rozyyev S, Armando I, Yang Z, Qu P, Jose PA. Dopamine D 5 receptor-mediated decreases in mitochondrial reactive oxygen species production are cAMP and autophagy dependent. Hypertens Res 2021; 44:628-641. [PMID: 33820956 PMCID: PMC8369611 DOI: 10.1038/s41440-021-00646-w] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2019] [Revised: 11/10/2019] [Accepted: 12/03/2019] [Indexed: 01/31/2023]
Abstract
Overproduction of reactive oxygen species (ROS) plays an important role in the pathogenesis of hypertension. The dopamine D5 receptor (D5R) is known to decrease ROS production, but the mechanism is not completely understood. In HEK293 cells overexpressing D5R, fenoldopam, an agonist of the two D1-like receptors, D1R and D5R, decreased the production of mitochondria-derived ROS (mito-ROS). The fenoldopam-mediated decrease in mito-ROS production was mimicked by Sp-cAMPS but blocked by Rp-cAMPS. In human renal proximal tubule cells with DRD1 gene silencing to eliminate the confounding effect of D1R, fenoldopam still decreased mito-ROS production. By contrast, Sch23390, a D1R and D5R antagonist, increased mito-ROS production in the absence of D1R, D5R is constitutively active. The fenoldopam-mediated inhibition of mito-ROS production may have been related to autophagy because fenoldopam increased the expression of the autophagy hallmark proteins, autophagy protein 5 (ATG5), and the microtubule-associated protein 1 light chain (LC)3-II. In the presence of chloroquine or spautin-1, inhibitors of autophagy, fenoldopam further increased ATG5 and LC3-II expression, indicating an important role of D5R in the positive regulation of autophagy. However, when autophagy was inhibited, fenoldopam was unable to inhibit ROS production. Indeed, the levels of these autophagy hallmark proteins were decreased in the kidney cortices of Drd5-/- mice. Moreover, ROS production was increased in mitochondria isolated from the kidney cortices of Drd5-/- mice, relative to Drd5+/+ littermates. In conclusion, D5R-mediated activation of autophagy plays a role in the D5R-mediated inhibition of mito-ROS production in the kidneys.
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Affiliation(s)
- Hewang Lee
- Department of Medicine, School of Medicine & Health Sciences, George Washington University, Washington, DC, USA,Institute of Heart and Vessel Diseases, Affiliated Second Hospital, Dalian Medical University, Dalian, China,Division of Nephrology, Department of Medicine, School of Medicine, University of Maryland, Baltimore, MD, USA,Center for Molecular Physiology Research, Children’s Research Institute, Children’s National Medical Center, Washington, DC, USA,Department of Pediatrics, Georgetown University Medical Center, Washington, DC, USA,Kidney Disease Section, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD, USA
| | - Xiaoliang Jiang
- Institute of Laboratory Animal Science, Chinese Academy of Medical Sciences & Comparative Medicine Center, Peking Union Medical College, Beijing, China
| | - Imran Perwaiz
- Institute of Heart and Vessel Diseases, Affiliated Second Hospital, Dalian Medical University, Dalian, China
| | - Peiying Yu
- Division of Nephrology, Department of Medicine, School of Medicine, University of Maryland, Baltimore, MD, USA,Center for Molecular Physiology Research, Children’s Research Institute, Children’s National Medical Center, Washington, DC, USA,Department of Pediatrics, Georgetown University Medical Center, Washington, DC, USA
| | - Jin Wang
- Institute of Heart and Vessel Diseases, Affiliated Second Hospital, Dalian Medical University, Dalian, China
| | - Ying Wang
- Institute of Heart and Vessel Diseases, Affiliated Second Hospital, Dalian Medical University, Dalian, China
| | - Maik Hüttemann
- Center for Molecular Medicine and Genetics and Cardiovascular Research Institute, School of Medicine, Wayne State University, Detroit, MI, USA
| | - Robin A. Felder
- Department of Pathology, University of Virginia Health Sciences Center, Charlottesville, VA, USA
| | - David R. Sibley
- Molecular Neuropharmacology Section, National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA
| | - Brian M. Polster
- Department of Anesthesiology, School of Medicine, University of Maryland, Baltimore, MD, USA
| | - Selim Rozyyev
- Department of Medicine, School of Medicine & Health Sciences, George Washington University, Washington, DC, USA
| | - Ines Armando
- Department of Medicine, School of Medicine & Health Sciences, George Washington University, Washington, DC, USA,Division of Nephrology, Department of Medicine, School of Medicine, University of Maryland, Baltimore, MD, USA,Center for Molecular Physiology Research, Children’s Research Institute, Children’s National Medical Center, Washington, DC, USA,Department of Pediatrics, Georgetown University Medical Center, Washington, DC, USA
| | - Zhiwei Yang
- Institute of Laboratory Animal Science, Chinese Academy of Medical Sciences & Comparative Medicine Center, Peking Union Medical College, Beijing, China
| | - Peng Qu
- Institute of Heart and Vessel Diseases, Affiliated Second Hospital, Dalian Medical University, Dalian, China
| | - Pedro A. Jose
- Department of Medicine, School of Medicine & Health Sciences, George Washington University, Washington, DC, USA,Division of Nephrology, Department of Medicine, School of Medicine, University of Maryland, Baltimore, MD, USA,Center for Molecular Physiology Research, Children’s Research Institute, Children’s National Medical Center, Washington, DC, USA,Department of Pediatrics, Georgetown University Medical Center, Washington, DC, USA,Department of Pharmacology and Physiology, School of Medicine & Health Sciences, George Washington University, Washington, DC, USA
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Majid DSA, Prieto MC, Navar LG. Salt-Sensitive Hypertension: Perspectives on Intrarenal Mechanisms. Curr Hypertens Rev 2015; 11:38-48. [PMID: 26028244 DOI: 10.2174/1573402111666150530203858] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Revised: 04/22/2015] [Accepted: 04/24/2015] [Indexed: 12/12/2022]
Abstract
Salt sensitive hypertension is characterized by increases in blood pressure in response to increases in dietary salt intake and is associated with an enhanced risk of cardiovascular and renal morbidity. Although researchers have sought for decades to understand how salt sensitivity develops in humans, the mechanisms responsible for the increases in blood pressure in response to high salt intake are complex and only partially understood. Until now, scientists have been unable to explain why some individuals are salt sensitive and others are salt resistant. Although a central role for the kidneys in the development of salt sensitivity and hypertension has been generally accepted, it is also recognized that hypertension is of multifactorial origin and a variety of factors can induce, or prevent, blood pressure responsiveness to the manipulation of salt intake. Excess salt intake in susceptible persons may also induce inappropriate central and sympathetic nervous system responses and increase the production of intrarenal angiotensin II, catecholamines and other factors such as oxidative stress and inflammatory cytokines. One key factor is the concomitant inappropriate or paradoxical activation of the intrarenal renin-angiotensin system, by high salt intake. This is reflected by the increases in urinary angiotensinogen during high salt intake in salt sensitive models. A complex interaction between neuroendocrine factors and the kidney may underlie the propensity for some individuals to retain salt and develop salt-dependent hypertension. In this review, we focus mainly on the renal contributions that provide the mechanistic links between chronic salt intake and the development of hypertension.
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Affiliation(s)
- Dewan S A Majid
- Department of Physiology, SL39, Tulane University School of Medicine, 1430 Tulane Avenue, New Orleans, LA 70112, USA.
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Gauthier KM, Campbell WB, McNeish AJ. Regulation of KCa2.3 and endothelium-dependent hyperpolarization (EDH) in the rat middle cerebral artery: the role of lipoxygenase metabolites and isoprostanes. PeerJ 2014; 2:e414. [PMID: 24949235 PMCID: PMC4060036 DOI: 10.7717/peerj.414] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Accepted: 05/15/2014] [Indexed: 01/21/2023] Open
Abstract
Background and Purpose. In rat middle cerebral arteries, endothelium-dependent hyperpolarization (EDH) is mediated by activation of calcium-activated potassium (KCa) channels specifically KCa2.3 and KCa3.1. Lipoxygenase (LOX) products function as endothelium-derived hyperpolarizing factors (EDHFs) in rabbit arteries by stimulating KCa2.3. We investigated if LOX products contribute to EDH in rat cerebral arteries. Methods. Arachidonic acid (AA) metabolites produced in middle cerebral arteries were measured using HPLC and LC/MS. Vascular tension and membrane potential responses to SLIGRL were simultaneously recorded using wire myography and intracellular microelectrodes. Results. SLIGRL, an agonist at PAR2 receptors, caused EDH that was inhibited by a combination of KCa2.3 and KCa3.1 blockade. Non-selective LOX-inhibition reduced EDH, whereas inhibition of 12-LOX had no effect. Soluble epoxide hydrolase (sEH) inhibition enhanced the KCa2.3 component of EDH. Following NO synthase (NOS) inhibition, the KCa2.3 component of EDH was absent. Using HPLC, middle cerebral arteries metabolized 14C-AA to 15- and 12-LOX products under control conditions. With NOS inhibition, there was little change in LOX metabolites, but increased F-type isoprostanes. 8-iso-PGF2α inhibited the KCa2.3 component of EDH. Conclusions. LOX metabolites mediate EDH in rat middle cerebral arteries. Inhibition of sEH increases the KCa2.3 component of EDH. Following NOS inhibition, loss of KCa2.3 function is independent of changes in LOX production or sEH inhibition but due to increased isoprostane production and subsequent stimulation of TP receptors. These findings have important implications in diseases associated with loss of NO signaling such as stroke; where inhibition of sEH and/or isoprostane formation may of benefit.
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Affiliation(s)
- Kathryn M Gauthier
- Department of Pharmacology and Toxicology, Medical College of Wisconsin , Milwaukee, WI , USA
| | - William B Campbell
- Department of Pharmacology and Toxicology, Medical College of Wisconsin , Milwaukee, WI , USA
| | - Alister J McNeish
- Reading School of Pharmacy, University of Reading , Reading, Berkshire , UK
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Epithelial-to-mesenchymal transition in podocytes mediated by activation of NADPH oxidase in hyperhomocysteinemia. Pflugers Arch 2011; 462:455-67. [PMID: 21647593 DOI: 10.1007/s00424-011-0981-y] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2011] [Revised: 04/20/2011] [Accepted: 05/23/2011] [Indexed: 02/07/2023]
Abstract
The present study tested the hypothesis that hyperhomocysteinemia (hHcys) induces podocytes to undergo epithelial-to-mesenchymal transition (EMT) through the activation of NADPH oxidase (Nox). It was found that increased homocysteine (Hcys) level suppressed the expression of slit diaphragm-associated proteins, P-cadherin and zonula occludens-1 (ZO-1), in conditionally immortalized mouse podocytes, indicating the loss of their epithelial features. Meanwhile, Hcys remarkably increased the abundance of mesenchymal markers, such as fibroblast specific protein-1 (FSP-1) and α-smooth muscle actin (α-SMA). These phenotype changes in podocytes induced by Hcys were accompanied by enhanced superoxide (O⁻₂) production, which was substantially suppressed by inhibition of Nox activity. Functionally, Hcys significantly enhanced the permeability of the podocyte monolayer coupled with increased EMT, and this EMT-related increase in cell permeability could be restored by Nox inhibitors. In mice lacking gp91( phox ) (gp91(-/-)), an essential Nox subunit gene, hHcys-enhanced podocyte EMT and consequent glomerular injury were examined. In wild-type (gp91(+/+)) mice, hHcys induced by a folate-free diet markedly enhanced expression of mesenchymal markers (FSP-1 and α-SMA) but decreased expression of epithelial markers of podocytes in glomeruli, which were not observed in gp91(-/-) mouse glomeruli. Podocyte injury, glomerular sclerotic pathology, and marked albuminuria observed in gp91(+/+) mice with hHcys were all significantly attenuated in gp91(-/-) mice. These results suggest that hHcys induces EMT of podocytes through activation of Nox, which represents a novel mechanism of hHcys-associated podocyte injury.
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Abstract
Increased vascular production of reactive oxygen species (ROS; termed oxidative stress) has been implicated in various chronic diseases, including hypertension. Oxidative stress is both a cause and a consequence of hypertension. Although oxidative injury may not be the sole etiology, it amplifies blood pressure elevation in the presence of other pro-hypertensive factors. Oxidative stress is a multisystem phenomenon in hypertension and involves the heart, kidneys, nervous system, vessels and possibly the immune system. Compelling experimental and clinical evidence indicates the importance of the vasculature in the pathophysiology of hypertension and as such much emphasis has been placed on the (patho)biology of ROS in the vascular system. A major source for cardiovascular, renal and neural ROS is a family of non-phagocytic nicotinamide adenine dinucleotide phosphate (NADPH) oxidases (Nox), including the prototypic Nox2 homolog-based NADPH oxidase, as well as other Noxes, such as Nox1 and Nox4. Nox-derived ROS is important in regulating endothelial function and vascular tone. Oxidative stress is implicated in endothelial dysfunction, inflammation, hypertrophy, apoptosis, migration, fibrosis, angiogenesis and rarefaction, important processes involved in vascular remodeling in hypertension. Despite a plethora of data implicating oxidative stress as a causative factor in experimental hypertension, findings in human hypertension are less conclusive. This review highlights the importance of ROS in vascular biology and focuses on the potential role of oxidative stress in human hypertension.
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Shahid M, Francis J, Matrougui K, Majid DSA. Involvement of tumor necrosis factor-alpha in natriuretic response to systemic infusion of nitric oxide synthase inhibitor in anesthetized mice. Am J Physiol Renal Physiol 2010; 299:F217-24. [PMID: 20410217 DOI: 10.1152/ajprenal.00611.2009] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Systemic infusion of TNF-alpha exerts renal vasoconstriction but caused marked natriuresis in mice. Similar renal responses were also observed during systemic infusion of nitric oxide (NO) synthase inhibitors as opposed to their usual antinatriuretic responses when administered intrarenally. In the present study, we examined the hypothesis that acute NO blockade systemically induces TNF-alpha generation. which induces this natriuretic response. Renal responses to intravenous infusion of the NO synthase inhibitor nitro-L-arginine methyl ester (L-NAME; 0.2 microg x min(-1) x g body wt(-1) for 85 min) and its impact on the plasma level of TNF-alpha were evaluated in anesthetized mice. Plasma TNF-alpha was undetected in untreated mice (n = 7) but was elevated in L-NAME-treated mice (109 +/- 22 pg/ml; P < 0.01 vs. untreated group; n = 7) along with an increase in TNF-alpha protein expression in kidney tissue. L-NAME infusion caused a usual increase in mean arterial pressure (MAP; 98 +/- 3 to 122 +/- 3 mmHg; P < 0.01) and decreases in renal blood flow (RBF; 8.6 +/- 0.3 to 4.4 +/- 0.2 ml x min(-1) x g(-1); P < 0.01) and glomerular filtration rate (GFR; 1.14 +/- 0.07 to 0.77 +/- 0.04 ml x min(-1) x g(-1); P < 0.01) with a marked increase in sodium excretion (U(Na)V; 0.48 +/- 0.10 to 3.52 +/- 0.85 micromol x min(-1) x g(-1); P < 0.01). Interestingly, in mice (n = 7) pretreated with the TNF-alpha blocker etanercept (5 mg/kg sc), the U(Na)V response to l-NAME infusion was markedly blunted (0.58 +/- 0.08 to 1.22 +/- 0.28 micromol x min(-1) x g(-1); P = NS) although responses for MAP, RBF, and GFR were mostly unchanged. However, pretreatment with the superoxide scavenger tempol in mice (n = 7) did not alter the U(Na)V response to L-NAME. These data demonstrate that L-NAME-induced natriuresis is mediated, at least in part, by concomitant generation of TNF-alpha during NO blockade.
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Affiliation(s)
- Mohd Shahid
- Department of Physiology and Tulane Hypertension and Renal Center of Excellence, Tulane University Health Sciences Center, New Orleans, LA 70112, USA
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