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Van Beusecum J, Inscho EW. Regulation of renal function and blood pressure control by P2 purinoceptors in the kidney. Curr Opin Pharmacol 2015; 21:82-8. [PMID: 25616035 PMCID: PMC5515225 DOI: 10.1016/j.coph.2015.01.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Revised: 12/24/2014] [Accepted: 01/05/2015] [Indexed: 12/11/2022]
Abstract
Kidneys are important regulators of extracellular fluid volume (ECFV) homeostasis. ECFV is a key regulatory component of long-term blood pressure control influenced by controlling tubular sodium transport. In recent decades, renal P2 purinoceptors (P2 receptors) have come to the forefront as a mechanism for regulating ECFV. P2 receptors are broadly distributed in renal tubular and vascular elements where they confer segmental control of renal vascular resistance, autoregulation, and tubular reabsorption. Activation or impairment of renal P2 purinoceptors is implicated in the regulating blood pressure or causing renal pathologies including hypertension. In this brief review, we discuss the role of renal vascular and tubular P2 purinoceptors in the regulation of renal hemodynamics, maintenance of ECFV, regulation of sodium reabsorption and the control of blood pressure.
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Affiliation(s)
- Justin Van Beusecum
- Division of Nephrology, Department of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Edward W Inscho
- Division of Nephrology, Department of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, 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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Horita S, Nakamura M, Shirai A, Yamazaki O, Satoh N, Suzuki M, Seki G. Regulatory roles of nitric oxide and angiotensin II on renal tubular transport. World J Nephrol 2014; 3:295-301. [PMID: 25374825 PMCID: PMC4220364 DOI: 10.5527/wjn.v3.i4.295] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/28/2014] [Revised: 09/05/2014] [Accepted: 10/10/2014] [Indexed: 02/06/2023] Open
Abstract
Renal tubules regulate blood pressure and humoral homeostasis. Mediators that play a significant role in regulating the transport of solutes and water include angiotensin II (AngII) and nitric oxide (NO). AngIIcan significantly raise blood pressure via effects on the heart, vasculature, and renal tubules. AngII generally stimulates sodium reabsorption by triggering sodium and fluid retention in almost all segments of renal tubules. Stimulation of renal proximal tubule (PT) transport is thought to be essential for AngII-mediated hypertension. However, AngII has a biphasic effect on in vitro PT transport in mice, rats, and rabbits: stimulation at low concentrations and inhibition at high concentrations. On the other hand, NO is generally thought to inhibit renal tubular transport. In PTs, NO seems to be involved in the inhibitory effect of AngII. A recent study reports a surprising finding: AngII has a monophasic stimulatory effect on human PT transport. Detailed analysis of signalling mechanisms indicates that in contrast to other species, the human NO/guanosine 3’,5’-cyclic monophosphate/extracellular signal-regulated kinase pathway seems to mediate this effect of Ang II on PT transport. In this review we will discuss recent progress in understanding the effects of AngII and NO on renal tubular transport.
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Dautzenberg M, Kahnert A, Stasch JP, Just A. Role of soluble guanylate cyclase in renal hemodynamics and autoregulation in the rat. Am J Physiol Renal Physiol 2014; 307:F1003-12. [DOI: 10.1152/ajprenal.00229.2014] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
We studied the influence of soluble guanylate (sGC) on renal blood flow (RBF), glomerular filtration rate (GFR), and RBF autoregulation and its role in mediating the hemodynamic effects of endogenous nitric oxide (NO). Arterial pressure (AP), heart rate (HR), RBF, GFR, urine flow (UV), and the efficiency and mechanisms of RBF autoregulation were studied in anesthetized rats during intravenous infusion of sGC activator cinaciguat before and (except GFR) also after inhibition of NO synthase (NOS) by Nω-nitro-l-arginine methyl ester. Cinaciguat (0.1, 0.3, 1, 3, 10 μg·kg−1·min−1, n = 7) reduced AP and increased HR, but did not significantly alter RBF. In clearance experiments (FITC-sinistrin, n = 7) GFR was not significantly altered by cinaciguat (0.1 and 1 μg·kg−1·min−1), but RBF slightly rose (+12%) and filtration fraction (FF) fell (−23%). RBF autoregulatory efficiency (67 vs. 104%) and myogenic response (33 vs. 44 units) were slightly depressed ( n = 9). NOS inhibition ( n = 7) increased AP (+38 mmHg), reduced RBF (−53%), and greatly augmented the myogenic response in RBF autoregulation (97 vs. 35 units), attenuating the other regulatory mechanisms. These changes were reversed by 77, 78, and 90% by 1 μg·kg−1·min−1 cinaciguat. In vehicle controls ( n = 3), in which cinaciguat-induced hypotension was mimicked by aortic compression, the NOS inhibition-induced changes were not affected. We conclude that sGC activation leaves RBF and GFR well maintained despite hypotension and only slightly impairs autoregulation. The ability to largely normalize AP, RBF, RBF autoregulation, and renovascular myogenic response after NOS inhibition indicates that these hemodynamic effects of NO are predominantly mediated via sGC.
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Affiliation(s)
- Marcel Dautzenberg
- Physiologisches Institut, Albert-Ludwigs-Universität, Freiburg, Germany; and
| | - Antje Kahnert
- Bayer HealthCare Pharmaceuticals, Cardiology/Hematology Research, Wuppertal, Germany
| | - Johannes-Peter Stasch
- Bayer HealthCare Pharmaceuticals, Cardiology/Hematology Research, Wuppertal, Germany
| | - Armin Just
- Physiologisches Institut, Albert-Ludwigs-Universität, Freiburg, Germany; and
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Cowley AW, Abe M, Mori T, O'Connor PM, Ohsaki Y, Zheleznova NN. Reactive oxygen species as important determinants of medullary flow, sodium excretion, and hypertension. Am J Physiol Renal Physiol 2014; 308:F179-97. [PMID: 25354941 DOI: 10.1152/ajprenal.00455.2014] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The physiological evidence linking the production of superoxide, hydrogen peroxide, and nitric oxide in the renal medullary thick ascending limb of Henle (mTAL) to regulation of medullary blood flow, sodium homeostasis, and long-term control of blood pressure is summarized in this review. Data obtained largely from rats indicate that experimentally induced elevations of either superoxide or hydrogen peroxide in the renal medulla result in reduction of medullary blood flow, enhanced Na(+) reabsorption, and hypertension. A shift in the redox balance between nitric oxide and reactive oxygen species (ROS) is found to occur naturally in the Dahl salt-sensitive (SS) rat model, where selective reduction of ROS production in the renal medulla reduces salt-induced hypertension. Excess medullary production of ROS in SS rats emanates from the medullary thick ascending limbs of Henle [from both the mitochondria and membrane NAD(P)H oxidases] in response to increased delivery and reabsorption of excess sodium and water. There is evidence that ROS and perhaps other mediators such as ATP diffuse from the mTAL to surrounding vasa recta capillaries, resulting in medullary ischemia, which thereby contributes to hypertension.
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Affiliation(s)
- Allen W Cowley
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Michiaki Abe
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Takefumi Mori
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Paul M O'Connor
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Yusuke Ohsaki
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
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Ortiz MC, Albertoni Borghese MF, Balonga SE, Lavagna A, Filipuzzi AL, Elesgaray R, Costa MA, Majowicz MP. Renal response to L-arginine in diabetic rats. A possible link between nitric oxide system and aquaporin-2. PLoS One 2014; 9:e104923. [PMID: 25111608 PMCID: PMC4128736 DOI: 10.1371/journal.pone.0104923] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2014] [Accepted: 07/15/2014] [Indexed: 11/18/2022] Open
Abstract
The aim of this study was to evaluate whether L-Arginine (L-Arg) supplementation modifies nitric oxide (NO) system and consequently aquaporin-2 (AQP2) expression in the renal outer medulla of streptozotocin-diabetic rats at an early time point after induction of diabetes. Male Wistar rats were divided in four groups: Control, Diabetic, Diabetic treated with L-Arginine and Control treated with L-Arginine. Nitric oxide synthase (NOS) activity was estimated by [14C] L-citrulline production in homogenates of the renal outer medulla and by NADPH-diaphorase staining in renal outer medullary tubules. Western blot was used to detect the expression of AQP2 and NOS types I and III; real time PCR was used to quantify AQP2 mRNA. The expression of both NOS isoforms, NOS I and NOS III, was decreased in the renal outer medulla of diabetic rats and L-Arg failed to prevent these decreases. However, L-Arg improved NO production, NADPH-diaphorase activity in collecting ducts and other tubular structures, and NOS activity in renal homogenates from diabetic rats. AQP2 protein and mRNA were decreased in the renal outer medulla of diabetic rats and L-Arg administration prevented these decreases. These results suggest that the decreased NOS activity in collecting ducts of the renal outer medulla may cause, at least in part, the decreased expression of AQP2 in this model of diabetes and constitute additional evidence supporting a role for NO in contributing to renal water reabsorption through the modulation of AQP2 expression in this pathological condition. However, we cannot discard that another pathway different from NOS also exists that links L-Arg to AQP2 expression.
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Affiliation(s)
- María C Ortiz
- Cátedra de Biología Celular y Molecular, Departamento de Ciencias Biológicas, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires. Buenos Aires, Argentina
| | - María F Albertoni Borghese
- Cátedra de Biología Celular y Molecular, Departamento de Ciencias Biológicas, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires. Buenos Aires, Argentina
| | - Sabrina E Balonga
- Cátedra de Biología Celular y Molecular, Departamento de Ciencias Biológicas, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires. Buenos Aires, Argentina
| | - Agustina Lavagna
- Cátedra de Biología Celular y Molecular, Departamento de Ciencias Biológicas, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires. Buenos Aires, Argentina
| | - Ana L Filipuzzi
- Cátedra de Biología Celular y Molecular, Departamento de Ciencias Biológicas, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires. Buenos Aires, Argentina
| | - Rosana Elesgaray
- Cátedra de Fisiología, Departamento de Ciencias Biológicas, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires. Buenos Aires, Argentina
| | - María A Costa
- Cátedra de Fisiología, Departamento de Ciencias Biológicas, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires. Buenos Aires, Argentina
| | - Mónica P Majowicz
- Cátedra de Biología Celular y Molecular, Departamento de Ciencias Biológicas, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires. Buenos Aires, Argentina
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Ivy JR, Bailey MA. Pressure natriuresis and the renal control of arterial blood pressure. J Physiol 2014; 592:3955-67. [PMID: 25107929 DOI: 10.1113/jphysiol.2014.271676] [Citation(s) in RCA: 98] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
The regulation of extracellular fluid volume by renal sodium excretion lies at the centre of blood pressure homeostasis. Renal perfusion pressure can directly regulate sodium reabsorption in the proximal tubule. This acute pressure natriuresis response is a uniquely powerful means of stabilizing long-term blood pressure around a set point. By logical extension, deviation from the set point can only be sustained if the pressure natriuresis mechanism is impaired, suggesting that hypertension is caused or sustained by a defect in the relationship between renal perfusion pressure and sodium excretion. Here we describe the role of pressure natriuresis in blood pressure control and outline the cascade of biophysical and paracrine events in the renal medulla that integrate the vascular and tubular response to altered perfusion pressure. Pressure natriuresis is impaired in hypertension and mechanistic insight into dysfunction comes from genetic analysis of blood pressure disorders. Transplantation studies in rats show that blood pressure is determined by the genotype of the kidney and Mendelian hypertension indicates that the distal nephron influences the overall natriuretic efficiency. These approaches and the outcomes of genome-wide-association studies broaden our view of blood pressure control, suggesting that renal sympathetic nerve activity and local inflammation can impair pressure natriuresis to cause hypertension. Understanding how these systems interact is necessary to tackle the global burden of hypertension.
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Affiliation(s)
- Jessica R Ivy
- British Heart Foundation Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, UK
| | - Matthew A Bailey
- British Heart Foundation Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, UK
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Ito D, Ito O, Mori N, Cao P, Suda C, Muroya Y, Hao K, Shimokawa H, Kohzuki M. Exercise training upregulates nitric oxide synthases in the kidney of rats with chronic heart failure. Clin Exp Pharmacol Physiol 2014; 40:617-25. [PMID: 23735016 DOI: 10.1111/1440-1681.12130] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2013] [Revised: 05/28/2013] [Accepted: 05/30/2013] [Indexed: 11/30/2022]
Abstract
There is an interaction between heart and kidney diseases, which is a condition termed cardiorenal syndrome. Exercise training has cardioprotective effects, involving upregulation of endothelial (e) nitric oxide synthase (NOS) in the cardiovascular system. However, the effects of exercise training on NOS in the kidney with heart disease are unknown. The aim of the present study was to investigate whether exercise training upregulates NOS in the kidney, left ventricle and aorta of rats with chronic heart failure (CHF). Male Sprague-Dawley rats underwent left coronary artery ligation (LCAL) to induce CHF and were randomly assigned to sedentary or treadmill exercise groups 4 weeks after LCAL. Three days after exercising for 4 weeks, urine samples were collected for 24 h and blood samples were collected following decapitation. Nitric oxide synthase activity and protein expression were examined. Significant interactions between CHF and exercise training were observed on parameters of cardiac and renal function. Exercise training improved cardiac function, decreased plasma B-type natriuretic peptide levels, decreased urinary albumin excretion and increased creatinine clearance in CHF rats. Nitric oxide synthase activity, eNOS expression and neuronal (n) NOS expression were significantly decreased in the left ventricle and kidney of CHF rats. Exercise training significantly increased NOS activity and eNOS and nNOS expression. Upregulation of NOS in the kidney and left ventricle may contribute, in part, to the renal and cardiac protective effects of exercise training in cardiorenal syndrome in CHF rats.
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Affiliation(s)
- Daisuke Ito
- Department of Internal Medicine and Rehabilitation Science, Tohoku University Graduate School of Medicine, Sendai, Japan.
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Burnstock G, Evans LC, Bailey MA. Purinergic signalling in the kidney in health and disease. Purinergic Signal 2014; 10:71-101. [PMID: 24265071 PMCID: PMC3944043 DOI: 10.1007/s11302-013-9400-5] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2013] [Accepted: 10/24/2013] [Indexed: 12/21/2022] Open
Abstract
The involvement of purinergic signalling in kidney physiology and pathophysiology is rapidly gaining recognition and this is a comprehensive review of early and recent publications in the field. Purinergic signalling involvement is described in several important intrarenal regulatory mechanisms, including tuboglomerular feedback, the autoregulatory response of the glomerular and extraglomerular microcirculation and the control of renin release. Furthermore, purinergic signalling influences water and electrolyte transport in all segments of the renal tubule. Reports about purine- and pyrimidine-mediated actions in diseases of the kidney, including polycystic kidney disease, nephritis, diabetes, hypertension and nephrotoxicant injury are covered and possible purinergic therapeutic strategies discussed.
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Affiliation(s)
- Geoffrey Burnstock
- Autonomic Neuroscience Centre, University College Medical School, Rowland Hill Street, London, NW3 2PF, UK,
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60
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Abstract
SIGNIFICANCE Renal oxidative stress can be a cause, a consequence, or more often a potentiating factor for hypertension. Increased reactive oxygen species (ROS) in the kidney have been reported in multiple models of hypertension and related to renal vasoconstriction and alterations of renal function. Nicotinamide adenine dinucleotide phosphate oxidase is the central source of ROS in the hypertensive kidney, but a defective antioxidant system also can contribute. RECENT ADVANCES Superoxide has been identified as the principal ROS implicated for vascular and tubular dysfunction, but hydrogen peroxide (H2O2) has been implicated in diminishing preglomerular vascular reactivity, and promoting medullary blood flow and pressure natriuresis in hypertensive animals. CRITICAL ISSUES AND FUTURE DIRECTIONS Increased renal ROS have been implicated in renal vasoconstriction, renin release, activation of renal afferent nerves, augmented contraction, and myogenic responses of afferent arterioles, enhanced tubuloglomerular feedback, dysfunction of glomerular cells, and proteinuria. Inhibition of ROS with antioxidants, superoxide dismutase mimetics, or blockers of the renin-angiotensin-aldosterone system or genetic deletion of one of the components of the signaling cascade often attenuates or delays the onset of hypertension and preserves the renal structure and function. Novel approaches are required to dampen the renal oxidative stress pathways to reduced O2(-•) rather than H2O2 selectivity and/or to enhance the endogenous antioxidant pathways to susceptible subjects to prevent the development and renal-damaging effects of hypertension.
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Affiliation(s)
- Magali Araujo
- Hypertension, Kidney and Vascular Research Center, Georgetown University , Washington, District of Columbia
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61
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Hoffman A, Okun-Gurevich M, Ovcharenko E, Goltsman I, Karram T, Cain C, Abassi Z, Winaver J. Renal effects of a novel endogenous natriuretic agent xanthurenic acid 8-o-β-d-glucoside in rats. Physiol Rep 2013; 1:e00155. [PMID: 24400157 PMCID: PMC3871470 DOI: 10.1002/phy2.155] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2013] [Revised: 10/18/2013] [Accepted: 10/21/2013] [Indexed: 12/28/2022] Open
Abstract
Xanthurenic acid 8-o-β-d-glucoside is an endogenous derivative of tryptophan metabolism, isolated from urine of patients with chronic renal disease. This compound was suggested previously to act as a natriuretic hormone based on its ability to block short circuit currents in a frog skin assay and to induce a sustained natriuresis when injected into rats (C. D. Cain et al., Proc. Natl. Acad. Sci. USA 2007: 17873-17878). The present communication describes the effects of the compound on renal clearance and hemodynamic parameters in male Sprague-Dawley rats maintained on a normal salt (0.4-0.5%) diet. Intravenous administration of synthetic xanthurenic acid 8-o-β-d-glucoside in two consecutive incremental doses (6.3 and 31.5 nmol) resulted in a significant increase (P < 0.05), in urine flow (43.91 ± 6.31 μL/min vs. 10.54 ± 2.21 μL/min), absolute rate of sodium excretion (3.99 ± 0.95 μEq/min vs. 1.15 ± μEq/min), and percentage sodium excretion (1.63 ± 0.46% vs. 0.37 ± 0.12%, peak response vs. baseline, respectively). The natriuretic/diuretic effect was associated also with a significant increase in potassium excretion. These effects were not related to changes in renal hemodynamics or in arterial blood pressure. Pretreatment with the sodium channel blocker, amiloride, completely abolished the natriuretic and kaluretic actions of the compound. Administration of the xanthurenic acid derivative caused a dose-related increase in urinary nitrite/nitrate excretion. Moreover, under chronic nitric oxide blockade by l-NG-Nitro-Arginine-Methyl-Esther (l-NAME) sodium excretion was similar in rats treated or untreated with the compound. Our data demonstrate that xanthurenic acid 8-o-β-d-glucoside has significant diuretic/natriuretic and kaluretic properties. An intact amiloride-sensitive sodium channel is required for the renal effects of the compound. The data further suggest that the natriuretic effect is mediated in part by a nitric oxide-dependent mechanism.
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Affiliation(s)
- Aaron Hoffman
- Department of Vascular Surgery and Transplantation, Technion Haifa, Israel ; Department of Physiology and Biophysics, Faculty of Medicine, Rambam Medical Center and the Rappaport Research Institute, Technion Haifa, Israel
| | - Marina Okun-Gurevich
- Department of Physiology and Biophysics, Faculty of Medicine, Rambam Medical Center and the Rappaport Research Institute, Technion Haifa, Israel
| | - Elena Ovcharenko
- Department of Physiology and Biophysics, Faculty of Medicine, Rambam Medical Center and the Rappaport Research Institute, Technion Haifa, Israel
| | - Ilia Goltsman
- Department of Physiology and Biophysics, Faculty of Medicine, Rambam Medical Center and the Rappaport Research Institute, Technion Haifa, Israel
| | - Tony Karram
- Department of Vascular Surgery and Transplantation, Technion Haifa, Israel
| | | | - Zaid Abassi
- Department of Physiology and Biophysics, Faculty of Medicine, Rambam Medical Center and the Rappaport Research Institute, Technion Haifa, Israel
| | - Joseph Winaver
- Department of Physiology and Biophysics, Faculty of Medicine, Rambam Medical Center and the Rappaport Research Institute, Technion Haifa, Israel
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Menzies RI, Zammit-Mangion A, Hollis LM, Lennen RJ, Jansen MA, Webb DJ, Mullins JJ, Dear JW, Sanguinetti G, Bailey MA. An anatomically unbiased approach for analysis of renal BOLD magnetic resonance images. Am J Physiol Renal Physiol 2013; 305:F845-52. [DOI: 10.1152/ajprenal.00113.2013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Oxygenation defects may contribute to renal disease progression, but the chronology of events is difficult to define in vivo without recourse to invasive methodologies. Blood oxygen level-dependent magnetic resonance imaging (BOLD MRI) provides an attractive alternative, but the R2* signal is physiologically complex. Postacquisition data analysis often relies on manual selection of region(s) of interest. This approach excludes from analysis significant quantities of biological information and is subject to selection bias. We present a semiautomated, anatomically unbiased approach to compartmentalize voxels into two quantitatively related clusters. In control F344 rats, low R2* clustering was located predominantly within the cortex and higher R2* clustering within the medulla (70.96 ± 1.48 vs. 79.00 ± 1.50; 3 scans per rat; n = 6; P < 0.01) consistent anatomically with a cortico-medullary oxygen gradient. An intravenous bolus of acetylcholine caused a transient reduction of the R2* signal in both clustered segments ( P < 0.01). This was nitric oxide dependent and temporally distinct from the hemodynamic effects of acetylcholine. Rats were then chronically infused with angiotensin II (60 ng/min) and rescanned 3 days later. Clustering demonstrated a disruption of the cortico-medullary gradient, producing less distinctly segmented mean R2* clusters (71.30 ± 2.00 vs. 72.48 ± 1.27; n = 6; NS). The acetylcholine-induced attenuation of the R2* signal was abolished by chronic angiotensin II infusion, consistent with reduced nitric oxide bioavailability. This global map of oxygenation, defined by clustering individual voxels on the basis of quantitative nearness, might be more robust in defining deficits in renal oxygenation than the absolute magnitude of R2* in small, manually selected regions of interest defined exclusively by anatomical nearness.
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Affiliation(s)
- Robert I. Menzies
- University/British Heart Foundation Centre for Cardiovascular Science, The University of Edinburgh, Edinburgh, United Kingdom; and
| | | | - Lyam M. Hollis
- University/British Heart Foundation Centre for Cardiovascular Science, The University of Edinburgh, Edinburgh, United Kingdom; and
| | - Ross J. Lennen
- University/British Heart Foundation Centre for Cardiovascular Science, The University of Edinburgh, Edinburgh, United Kingdom; and
| | - Maurits A. Jansen
- University/British Heart Foundation Centre for Cardiovascular Science, The University of Edinburgh, Edinburgh, United Kingdom; and
| | - David J. Webb
- University/British Heart Foundation Centre for Cardiovascular Science, The University of Edinburgh, Edinburgh, United Kingdom; and
| | - John J. Mullins
- University/British Heart Foundation Centre for Cardiovascular Science, The University of Edinburgh, Edinburgh, United Kingdom; and
| | - James W. Dear
- University/British Heart Foundation Centre for Cardiovascular Science, The University of Edinburgh, Edinburgh, United Kingdom; and
| | - Guido Sanguinetti
- School of Informatics, The University of Edinburgh, Edinburgh, United Kingdom
| | - Matthew A. Bailey
- University/British Heart Foundation Centre for Cardiovascular Science, The University of Edinburgh, Edinburgh, United Kingdom; and
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Hultström M. Neurohormonal interactions on the renal oxygen delivery and consumption in haemorrhagic shock-induced acute kidney injury. Acta Physiol (Oxf) 2013; 209:11-25. [PMID: 23837642 DOI: 10.1111/apha.12147] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2013] [Revised: 07/02/2013] [Accepted: 07/04/2013] [Indexed: 12/14/2022]
Abstract
Haemorrhagic shock is a common cause of acute kidney injury (AKI), which is a major risk factor for developing chronic kidney disease. The mechanism is superficially straightforward. An arterial pressure below the kidney's autoregulatory region leads to a direct reduction in filtration pressure and perfusion, which in turn cause renal failure with reduced glomerular filtration rate and AKI because of hypoxia. However, the kidney's situation is further worsened by the hormonal and neural reactions to reduced perfusion pressure. There are three major systems working to maintain arterial pressure in shock: sympathetic signalling, the renin-angiotensin system and vasopressin. These work to retain electrolytes and water and to increase peripheral resistance and cardiac output. In the kidney, the increased electrolyte reabsorption consumes oxygen. At the same time, at the signalling level seen in shock, all of these hormones reduce renal perfusion and thereby oxygen delivery. This creates an exaggerated hypoxic situation that is liable to worsen the AKI. The present review will examine this mechanistic background and identify a number of areas that require further studies. At this time, the ideal treatment of haemorrhagic shock appears to be slow fluid resuscitation, possibly with hyperosmolar sodium, low chloride and no artificial colloids. From the standpoint of the kidney, renin-angiotensin system inhibitors appear fruitful for further study.
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Affiliation(s)
- M Hultström
- Unit for Integrative Physiology, Department of Medical Cellbiology, Uppsala University, Uppsala, Sweden; Anaesthesiology and Intensive Care, Department of Surgical Sciences, Uppsala University, Uppsala, Sweden
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Abstract
PURPOSE OF REVIEW Endogenous cardiotonic steroids (CTS) exert long-term effects on salt and blood pressure homeostasis. Here we discuss recent observations on mechanisms of salt sensitivity that involve endogenous ouabain and novel pathways in the brain and discuss their possible relationship to arterial and renal function in hypertension. RECENT FINDINGS Chronic elevation of brain sodium promotes sustained hypertension mediated by central endogenous ouabain and the Na(+) pump α-2 catalytic subunit. The intermediary pressor mechanism in the brain involves aldosterone biosynthesis, activation of mineralocorticoid receptors and increased epithelial sodium channel activity. In the periphery, elevated plasma CTS raise contractility and blood pressure by augmentation of sympathetic nerve responses, increasing arterial Ca(2+) signaling and blunting nitric oxide production in the renal medulla and collecting ducts. SUMMARY Endogenous ouabain in the brain appears to play a critical role in salt sensitivity and hypertension. In the periphery, the J-shaped relationship of plasma endogenous ouabain in response to short-term changes in salt balance in humans raises the possibility that endogenous ouabain contributes to the increased risk of adverse cardiovascular events associated with both low and high salt intakes.
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Ren Y, D'Ambrosio MA, Garvin JL, Wang H, Carretero OA. Mechanism of inhibition of tubuloglomerular feedback by CO and cGMP. Hypertension 2013; 62:99-104. [PMID: 23648700 DOI: 10.1161/hypertensionaha.113.01164] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Tubuloglomerular feedback (TGF) is a mechanism that senses NaCl in the macula densa (MD) and causes constriction of the afferent arteriole. CO, either endogenous or exogenous, inhibits TGF at least in part via cGMP. We hypothesize that CO in the MD, acting via both cGMP-dependent and -independent mechanisms, attenuates TGF by acting downstream from depolarization and calcium entry into the MD cells. In vitro, microdissected rabbit afferent arterioles and their MD were simultaneously perfused and TGF was measured as the decrease in afferent arteriole diameter. MD depolarization was induced with ionophores, while adding the CO-releasing molecule-3 to the MD perfusate at nontoxic concentrations. CO-releasing molecule-3 blunted depolarization-induced TGF at 50 μmol/L, from 3.6±0.4 to 2.5±0.4 µm (P<0.01), and abolished it at 100 μmol/L, to 0.1±0.1 μm (P<0.001; n=6). When cGMP generation was blocked by guanylyl cyclase inhibitor LY83583 added to the MD, CO-releasing molecule-3 no longer affected depolarization-induced TGF at 50 μmol/L (2.9±0.4 versus 3.0±0.4 µm) but partially inhibited TGF at 100 μmol/L (to 1.3±0.2 μm; P<0.05; n=9). Experiments using eicosatetraynoic acid and indomethacin suggest arachidonic acid metabolites do not mediate the cGMP-independent effect of CO. We then added the calcium ionophore A23187 to the MD, which caused TGF (4.1±0.6 μmol/L); A23187-induced TGF was inhibited by CO-releasing molecule-3 at 50 μmol/L (1.9±0.6 μmol/L; P<0.01) and 100 μmol/L (0.2±0.5 μmol/L; P<0.001; n=6). We conclude that CO inhibits TGF acting downstream from depolarization and calcium entry, acting via cGMP at low concentrations, but additional mechanisms of action may be involved at higher concentrations.
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Affiliation(s)
- Yilin Ren
- Hypertension and Vascular Research Division, Department of Internal Medicine, Henry Ford Hospital, Detroit, MI 48202, USA
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66
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Althaus M, Clauss WG. Gasotransmitters: novel regulators of ion channels and transporters. Front Physiol 2013; 4:27. [PMID: 23437016 PMCID: PMC3578291 DOI: 10.3389/fphys.2013.00027] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2013] [Accepted: 02/05/2013] [Indexed: 11/13/2022] Open
Affiliation(s)
- Mike Althaus
- Department of Molecular Cell Physiology, Institute of Animal Physiology, Justus-Liebig University of Giessen Giessen, Germany
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67
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Ito D, Ito O, Cao P, Mori N, Suda C, Muroya Y, Takashima K, Ito S, Kohzuki M. Effects of exercise training on nitric oxide synthase in the kidney of spontaneously hypertensive rats. Clin Exp Pharmacol Physiol 2013; 40:74-82. [DOI: 10.1111/1440-1681.12040] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2012] [Revised: 11/30/2013] [Accepted: 12/03/2012] [Indexed: 02/06/2023]
Affiliation(s)
- Daisuke Ito
- Department of Internal Medicine and Rehabilitation Science; Tohoku University Graduate School of Medicine; Sendai; Japan
| | | | - Pengyu Cao
- Department of Internal Medicine and Rehabilitation Science; Tohoku University Graduate School of Medicine; Sendai; Japan
| | | | - Chihiro Suda
- Department of Internal Medicine and Rehabilitation Science; Tohoku University Graduate School of Medicine; Sendai; Japan
| | - Yoshikazu Muroya
- Department of Internal Medicine and Rehabilitation Science; Tohoku University Graduate School of Medicine; Sendai; Japan
| | - Kenta Takashima
- Department of Internal Medicine and Rehabilitation Science; Tohoku University Graduate School of Medicine; Sendai; Japan
| | - Sadayoshi Ito
- Center for Advanced Integrated Renal Science; Tohoku University Graduate School of Medicine; Sendai; Japan
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68
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Nauli SM, Jin X, AbouAlaiwi WA, El-Jouni W, Su X, Zhou J. Non-motile primary cilia as fluid shear stress mechanosensors. Methods Enzymol 2013; 525:1-20. [PMID: 23522462 PMCID: PMC4096622 DOI: 10.1016/b978-0-12-397944-5.00001-8] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Primary cilia are sensory organelles that transmit extracellular signals into intracellular biochemical responses. Structural and functional defects in primary cilia are associated with a group of human diseases, known as ciliopathies, with phenotypes ranging from cystic kidney and obesity to blindness and mental retardation. Primary cilia mediate mechano- and chemosensation in many cell types. The mechanosensory function of the primary cilia requires the atypical G-protein-coupled receptor polycystin-1 and the calcium-permeable nonselective cation channel polycystin-2. Mechanical stimulations such as fluid-shear stress of the primary cilia initiate intracellular calcium rise, nitric oxide release, and protein modifications. In this review, we describe a set of protocols for cell culture to promote ciliation, mechanical stimulations of the primary cilia, and measurements of calcium rise and nitric oxide release induced by fluid shear stress.
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Affiliation(s)
- Surya M. Nauli
- Department of Pharmacology, The University of Toledo, Toledo, Ohio, USA
| | - Xingjian Jin
- Department of Pharmacology, The University of Toledo, Toledo, Ohio, USA
| | | | - Wassim El-Jouni
- Renal Division, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Xuefeng Su
- Renal Division, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Jing Zhou
- Renal Division, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, USA
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Montanari A, Biggi A, Cabassi A, Pelloni I, Pigazzani F, Pinelli S, Pelà G, Musiari L, Cherney DZ. Renal hemodynamic response to L-arginine in uncomplicated, type 1 diabetes mellitus: the role of buffering anions and tubuloglomerular feedback. Am J Physiol Renal Physiol 2012; 303:F648-58. [PMID: 22739534 DOI: 10.1152/ajprenal.00149.2012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
According to the "tubulocentric" hypothesis of the glomerular hyperfiltration of diabetes mellitus (DM), tubuloglomerular feedback (TGF) is the critical determinant of the related renal hemodynamic dysfunction. To examine the role of TGF in human type 1 DM, 12 salt-replete healthy (C) and 11 uncomplicated DM individuals underwent measurements of glomerular filtration rate (GFR), renal blood flow (RBF), and lithium-derived absolute "distal" sodium delivery (DDNa). Measurements were made during two 3-h infusions of 0.012 mmol·kg(-1)·min(-1) l-arginine (ARG) buffered with either equimolar HCl (ARG.HCl) or citric acid (ARG.CITR). Our hypothesis was that changes in TGF signaling would be directionally opposite ARG.HCl vs. ARG.CITR according to the effects of the ARG-buffering anion on DDNa. Similar changes in C and DM followed ARG.CITR, with declines in DDNa (-0.26 ± 0.07 mmol/min C vs. -0.31 ± 0.07 mmol/min DM) and increases in RBF (+299 ± 25 vs. +319 ± 29 ml·min(-1)·1.73 m(-2)) and GFR (+6.6 ± 0.8 vs. +11.6 ± 1.2 ml·min(-1)·1.73 m(-2)). In contrast, with ARG.HCl, DDNa rose in both groups (P = 0.001), but the response was 73% greater in DM (+1.50 ± 0.15 mmol/min C vs. +2.59 ± 0.22 mmol/min DM, P = 0.001). RBF also increased (P = 0.001, +219 ± 20 ml·min(-1)·1.73 m(-2) C, +105 ± 14 DM), but ΔRBF after ARG.HCl was lower vs. ARG.CITR in both groups (P = 0.001). After ARG.HCl, ΔRBF also was 50% lower in DM vs. C (P = 0.001) and GFR, unchanged in C, declined in DM (-7.4 ± 0.9 ml·min(-1)·1.73 m(-2), P = 0.02 vs. C). After ARG.HCl, unlike ARG.CITR, DDNa increased in C and DM, associated with less ΔRBF and ΔGFR vs. ARG.CITR. This suggests that the renal hemodynamic response to ARG is influenced substantially by the opposite actions of HCl vs. CITR on DDNa and TGF. In DM, the association of ARG.HCl-induced exaggerated ΔDDNa, blunted ΔRBF, and the decline in GFR vs. C shows an enhanced TGF dependence of renal vasodilatation to ARG, in agreement with a critical role of TGF in DM-related renal hemodynamic dysfunction.
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Affiliation(s)
- Alberto Montanari
- Dipartimento di Medicina Clinica e Sperimentale, Università di Parma and Azienda Ospedaliero-Universitaria di Parma, Via Gramsci 14, Parma, Italy.
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70
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Liao YC, Lee YH, Chuang LY, Guh JY, Shi MD, Huang JS. Advanced glycation end products-mediated hypertrophy is negatively regulated by tetrahydrobiopterin in renal tubular cells. Mol Cell Endocrinol 2012; 355:71-7. [PMID: 22326994 DOI: 10.1016/j.mce.2012.01.018] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/21/2011] [Revised: 12/30/2011] [Accepted: 01/20/2012] [Indexed: 01/10/2023]
Abstract
Diabetic nephropathy (DN) is the most common cause of end-stage renal disease worldwide. The accumulation of advanced glycation end products (AGE) is a key mediator of renal tubular hypertrophy in DN. Elimination of tetrahydrobiopterin (BH(4)) and nitric oxide (NO) bioavailability may contribute to the aggravation of DN. The present study aims to explore any possible beneficial effect of exogenous BH(4) in alleviating the AGE-induced renal tubular hypertrophy in DN. Thus, renal tubular cells were treated with BH(4), BH(2), sepiapterin, or DAHP in the presence of AGE. We found that AGE (but not non-glycated BSA) markedly reduced NO production and increased hypertrophy index in these cells. Exogenous BH(4)/BH(2) and sepiapterin treatments attenuated AGE-inhibited the iNOS/NO/GTPCH I protein synthesis. Moreover, BH(4) and BH(2) significantly reversed AGE-enhanced the JAK2-STAT1/STAT3 activation. The abilities of BH(4) and BH(2) to inhibit AGE-induced renal cellular hypertrophy were verified by the observation that BH(4) and BH(2) inhibited hypertrophic growth and the protein synthesis of p27(Kip1) and α-SMA. These findings indicate for the first time that exogenous BH(4) and BH(2) attenuate AGE-induced hypertrophic effect at least partly by increasing the iNOS/GTPCH I synthesis and NO generation in renal tubular cells.
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Affiliation(s)
- Yi-Chen Liao
- Department of Dermatology, Chi Mei Medical Center, Tainan, Taiwan, ROC
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71
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Althaus M. Gasotransmitters: novel regulators of epithelial na(+) transport? Front Physiol 2012; 3:83. [PMID: 22509167 PMCID: PMC3321473 DOI: 10.3389/fphys.2012.00083] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2012] [Accepted: 03/20/2012] [Indexed: 11/13/2022] Open
Abstract
The vectorial transport of Na(+) across epithelia is crucial for the maintenance of Na(+) and water homeostasis in organs such as the kidneys, lung, or intestine. Dysregulated Na(+) transport processes are associated with various human diseases such as hypertension, the salt-wasting syndrome pseudohypoaldosteronism type 1, pulmonary edema, cystic fibrosis, or intestinal disorders, which indicate that a precise regulation of epithelial Na(+) transport is essential. Novel regulatory signaling molecules are gasotransmitters. There are currently three known gasotransmitters: nitric oxide (NO), carbon monoxide (CO), and hydrogen sulfide (H(2)S). These molecules are endogenously produced in mammalian cells by specific enzymes and have been shown to regulate various physiological processes. There is a growing body of evidence which indicates that gasotransmitters may also regulate Na(+) transport across epithelia. This review will summarize the available data concerning NO, CO, and H(2)S dependent regulation of epithelial Na(+) transport processes and will discuss whether or not these mediators can be considered as true physiological regulators of epithelial Na(+) transport biology.
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Affiliation(s)
- Mike Althaus
- Institute of Animal Physiology, Justus Liebig University of Giessen Giessen, Germany
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73
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Ferreri NR, Hao S, Pedraza PL, Escalante B, Vio CP. Eicosanoids and tumor necrosis factor-alpha in the kidney. Prostaglandins Other Lipid Mediat 2011; 98:101-6. [PMID: 22101002 DOI: 10.1016/j.prostaglandins.2011.11.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2011] [Revised: 10/31/2011] [Accepted: 11/03/2011] [Indexed: 12/14/2022]
Abstract
The thick ascending limb of Henle's loop (TAL) is capable of metabolizing arachidonic acid (AA) by cytochrome P450 (CYP450) and cyclooxygenase (COX) pathways and has been identified as a nephron segment that contributes to salt-sensitive hypertension. Previous studies demonstrated a prominent role for CYP450-dependent metabolism of AA to products that inhibited ion transport pathways in the TAL. However, COX-2 is constitutively expressed along all segments of the TAL and is increased in response to diverse stimuli. The ability of Tamm-Horsfall glycoprotein, a selective marker of cortical TAL (cTAL) and medullary (mTAL), to bind TNF and localize it to this nephron segment prompted studies to determine the capacity of mTAL cells to produce TNF and determine its effects on mTAL function. The colocalization of calcium-sensing receptor (CaR) and COX-2 in the TAL supports the notion that activation of CaR induces TNF-dependent COX-2 expression and PGE₂ synthesis in mTAL cells. Additional studies showed that TNF produced by mTAL cells inhibits ⁸⁶Rb uptake, an in vitro correlate of natriuresis, in an autocrine- and COX-2-dependent manner. The molecular mechanism for these effects likely includes inhibition of Na⁺-K⁺-2Cl⁻ cotransporter (NKCC2) expression and trafficking.
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Affiliation(s)
- Nicholas R Ferreri
- Department of Pharmacology, New York Medical College, Valhalla, NY 10595, USA.
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74
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Abstract
The distal nephron plays a critical role in the renal control of homeostasis. Until very recently most studies focused on the control of Na(+), K(+), and water balance by principal cells of the collecting duct and the regulation of solute and water by hormones from the renin-angiotensin-aldosterone system and by antidiuretic hormone. However, recent studies have revealed the unexpected importance of renal intercalated cells, a subtype of cells present in the connecting tubule and collecting ducts. Such cells were thought initially to be involved exclusively in acid-base regulation. However, it is clear now that intercalated cells absorb NaCl and K(+) and hence may participate in the regulation of blood pressure and potassium balance. The second paradigm-challenging concept we highlight is the emerging importance of local paracrine factors that play a critical role in the renal control of water and electrolyte balance.
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Affiliation(s)
- Dominique Eladari
- Centre de Recherche des Cordeliers, Université Paris Descartes, INSERM UMRS 872, Equipe 3, F-75006, Paris, France; ,
- Université Pierre et Marie Curie, CNRS ERL7226, F-75006, Paris, France
- Département de Physiologie, Hôpital Européen Georges Pompidou, Assistance Publique-Hôpitaux de Paris, F-75015, Paris, France
| | - Régine Chambrey
- Centre de Recherche des Cordeliers, Université Paris Descartes, INSERM UMRS 872, Equipe 3, F-75006, Paris, France; ,
- Université Pierre et Marie Curie, CNRS ERL7226, F-75006, Paris, France
| | - Janos Peti-Peterdi
- Department of Physiology and Biophysics, Keck School of Medicine, Zilkha Neurogenetic Institute, University of Southern California, Los Angeles, California 90033;
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75
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Zhang Y, Jose PA, Zeng C. Regulation of sodium transport in the proximal tubule by endothelin. CONTRIBUTIONS TO NEPHROLOGY 2011; 172:63-75. [PMID: 21893989 DOI: 10.1159/000328684] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Human essential hypertension and rodent genetic hypertension are associated with increased sodium transport in the renal proximal tubule and medullary thick ascending limb of Henle. The proximal tubule, which secretes endothelin (ET), expresses the ET(B) receptor. Low (nM) concentrations of ET, via the ET(B) receptor, inhibit sodium and water transport and ATP-driven drug secretion in the proximal tubule. In contrast, very low (pM) and high nM concentrations of ET increase renal proximal sodium transport, but the receptor involved remains to be determined. The natriuretic effect of ET(B) receptor stimulation is impaired in spontaneously hypertensive rats, due in part to a defective interaction with D(3) dopamine and angiotensin II type 1 receptors. Impaired ET(B) receptor function in the renal proximal tubule may be important in the pathogenesis of genetic hypertension.
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76
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Wesseling S, Essers PB, Koeners MP, Pereboom TC, Braam B, van Faassen EE, Macinnes AW, Joles JA. Perinatal exogenous nitric oxide in fawn-hooded hypertensive rats reduces renal ribosomal biogenesis in early life. Front Genet 2011; 2:52. [PMID: 22303348 PMCID: PMC3268605 DOI: 10.3389/fgene.2011.00052] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2011] [Accepted: 08/02/2011] [Indexed: 01/21/2023] Open
Abstract
Nitric oxide (NO) is known to depress ribosome biogenesis in vitro. In this study we analyzed the influence of exogenous NO on ribosome biogenesis in vivo using a proven antihypertensive model of perinatal NO administration in genetically hypertensive rats. Fawn-hooded hypertensive rat (FHH) dams were supplied with the NO-donor molsidomine in drinking water from 2 weeks before to 4 weeks after birth, and the kidneys were subsequently collected from 2 day, 2 week, and 9 to 10-month-old adult offspring. Although the NO-donor increased maternal NO metabolite excretion, the NO status of juvenile renal (and liver) tissue was unchanged as assayed by EPR spectroscopy of NO trapped with iron-dithiocarbamate complexes. Nevertheless, microarray analysis revealed marked differential up-regulation of renal ribosomal protein genes at 2 days and down-regulation at 2 weeks and in adult males. Such differential regulation of renal ribosomal protein genes was not observed in females. These changes were confirmed in males at 2 weeks by expression analysis of renal ribosomal protein L36a and by polysome profiling, which also revealed a down-regulation of ribosomes in females at that age. However, renal polysome profiles returned to normal in adults after early exposure to molsidomine. No direct effects of molsidomine were observed on cellular proliferation in kidneys at any age, and the changes induced by molsidomine in renal polysome profiles at 2 weeks were absent in the livers of the same rats. Our results suggest that the previously found prolonged antihypertensive effects of perinatal NO administration may be due to epigenetically programmed alterations in renal ribosome biogenesis during a critical fetal period of renal development, and provide a salient example of a drug-induced reduction of ribosome biogenesis that is accompanied by a beneficial long-term health effect in both males and females.
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Affiliation(s)
- Sebastiaan Wesseling
- Department of Nephrology and Hypertension, University Medical Center Utrecht, Netherlands
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77
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Gomes GN, Gil FZ. Prenatally programmed hypertension: role of maternal diabetes. Braz J Med Biol Res 2011; 44:899-904. [PMID: 21876875 DOI: 10.1590/s0100-879x2011007500109] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2011] [Accepted: 08/05/2011] [Indexed: 01/08/2023] Open
Abstract
Epidemiological and experimental studies have led to the hypothesis of the fetal origin of adult diseases, suggesting that some adult diseases might be determined before birth by altered fetal development. Maternal diabetes subjects the fetus to an adverse environment that has been demonstrated to result in metabolic, cardiovascular and renal impairment in the offspring. The growing amount of obesity in young females in developed and some developing countries should contribute to increasing the incidence of diabetes among pregnant women. In this review, we discuss how renal and extrarenal mechanisms participate in the genesis of hypertension induced by a diabetic status during fetal development.
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Affiliation(s)
- G N Gomes
- Disciplina Fisiologia Renal e Termometabologia, Departamento de Fisiologia, Universidade Federal de São Paulo, Brasil.
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78
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Guanine-induced inhibition of renal Na(+)-ATPase activity: evidence for the involvement of the Gi protein-coupled receptor. Arch Biochem Biophys 2011; 513:126-30. [PMID: 21784058 DOI: 10.1016/j.abb.2011.07.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2011] [Revised: 06/29/2011] [Accepted: 07/07/2011] [Indexed: 01/13/2023]
Abstract
There is some evidence to show a possible role of guanosine in the modulation of cellular function, in particular, in the neuronal system. However, nothing is known about the role of guanine in renal function. The aim of the present work was to investigate the role of guanine on modulation of Na+-ATPase activity in isolated basolateral membrane (BLM) of the renal cortex. Guanine inhibited the enzyme activity in a dose-dependent manner with maximal effect (56%) obtained at 10⁻⁶ M. This effect was reversed by DPCPX (8-cyclopentyl-1,3-dipropylxanthine), an antagonist of A₁ receptors, but it was not changed by 10⁻⁸ M DMPX (3,7-dimethyl-1-propargylxanthine) or 10⁻⁸ M MRS (2,3-diethyl-4,5-dipropyl-6-phenylpyridine-3-thiocarboxylate-5-carboxylate), antagonists of A₂ and A₃ receptors, respectively. Furthermore, it was observed that guanine increased [γ-³⁵S]GTP-specific binding with the maximal effect observed at 10⁻⁶ M and this effect was abolished by 10⁻⁶ M GDPβS. The inhibitory effect of 10⁻⁶ M guanine on Na+-ATPase activity was reversed by 10⁻⁶ M GDPβS, 10⁻⁶ M forskolin, 10⁻⁶ M pertussis toxin and 10⁻⁸ M cholera toxin. These results indicate that guanine binds to a DPCPX-sensitive receptor promoting the activation of Gi protein and leading to a decrease in cAMP level and, consequently, inhibition of BLM Na+-ATPase activity.
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Jung J, Basile DP, Pratt JH. Sodium reabsorption in the thick ascending limb in relation to blood pressure: a clinical perspective. Hypertension 2011; 57:873-9. [PMID: 21403087 DOI: 10.1161/hypertensionaha.108.120246] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Jeesun Jung
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN, USA
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