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Effects of Nitric Oxide on Renal Proximal Tubular Na + Transport. BIOMED RESEARCH INTERNATIONAL 2017; 2017:6871081. [PMID: 29181400 PMCID: PMC5664255 DOI: 10.1155/2017/6871081] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Accepted: 09/14/2017] [Indexed: 12/28/2022]
Abstract
Nitric oxide (NO) has a wide variety of physiological functions in the kidney. Besides the regulatory effects in intrarenal haemodynamics and glomerular microcirculation, in vivo studies reported the diuretic and natriuretic effects of NO. However, opposite results showing the stimulatory effect of NO on Na+ reabsorption in the proximal tubule led to an intense debate on its physiological roles. Animal studies have showed the biphasic effect of angiotensin II (Ang II) and the overall inhibitory effect of NO on the activity of proximal tubular Na+ transporters, the apical Na+/H+ exchanger isoform 3, basolateral Na+/K+ ATPase, and the Na+/HCO3− cotransporter. However, whether these effects could be reproduced in humans remained unclear. Notably, our recent functional analysis of isolated proximal tubules demonstrated that Ang II dose-dependently stimulated human proximal tubular Na+ transport through the NO/guanosine 3′,5′-cyclic monophosphate (cGMP) pathway, confirming the human-specific regulation of proximal tubular transport via NO and Ang II. Of particular importance for this newly identified pathway is its possibility of being a human-specific therapeutic target for hypertension. In this review, we focus on NO-mediated regulation of proximal tubular Na+ transport, with emphasis on the interaction with individual Na+ transporters and the crosstalk with Ang II signalling.
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Boldt C, Röschel T, Himmerkus N, Plain A, Bleich M, Labes R, Blum M, Krause H, Magheli A, Giesecke T, Mutig K, Rothe M, Weldon SM, Dragun D, Schunck WH, Bachmann S, Paliege A. Vasopressin lowers renal epoxyeicosatrienoic acid levels by activating soluble epoxide hydrolase. Am J Physiol Renal Physiol 2016; 311:F1198-F1210. [PMID: 27681558 DOI: 10.1152/ajprenal.00062.2016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Accepted: 09/19/2016] [Indexed: 11/22/2022] Open
Abstract
Activation of the thick ascending limb (TAL) Na+-K+-2Cl- cotransporter (NKCC2) by the antidiuretic hormone arginine vasopressin (AVP) is an essential mechanism of renal urine concentration and contributes to extracellular fluid and electrolyte homeostasis. AVP effects in the kidney are modulated by locally and/or by systemically produced epoxyeicosatrienoic acid derivates (EET). The relation between AVP and EET metabolism has not been determined. Here, we show that chronic treatment of AVP-deficient Brattleboro rats with the AVP V2 receptor analog desmopressin (dDAVP; 5 ng/h, 3 days) significantly lowered renal EET levels (-56 ± 3% for 5,6-EET, -50 ± 3.4% for 11,12-EET, and -60 ± 3.7% for 14,15-EET). The abundance of the principal EET-degrading enzyme soluble epoxide hydrolase (sEH) was increased at the mRNA (+160 ± 37%) and protein levels (+120 ± 26%). Immunohistochemistry revealed dDAVP-mediated induction of sEH in connecting tubules and cortical and medullary collecting ducts, suggesting a role of these segments in the regulation of local interstitial EET signals. Incubation of murine kidney cell suspensions with 1 μM 14,15-EET for 30 min reduced phosphorylation of NKCC2 at the AVP-sensitive threonine residues T96 and T101 (-66 ± 5%; P < 0.05), while 14,15-DHET had no effect. Concomitantly, isolated perfused cortical thick ascending limb pretreated with 14,15-EET showed a 30% lower transport current under high and a 70% lower transport current under low symmetric chloride concentrations. In summary, we have shown that activation of AVP signaling stimulates renal sEH biosynthesis and enzyme activity. The resulting reduction of EET tissue levels may be instrumental for increased NKCC2 transport activity during AVP-induced antidiuresis.
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Affiliation(s)
- Christin Boldt
- Department of Anatomy, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Tom Röschel
- Department of Anatomy, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Nina Himmerkus
- Department of Physiology, Christian-Albrechts-University, Kiel, Germany
| | - Allein Plain
- Department of Physiology, Christian-Albrechts-University, Kiel, Germany
| | - Markus Bleich
- Department of Physiology, Christian-Albrechts-University, Kiel, Germany
| | - Robert Labes
- Department of Anatomy, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Maximilian Blum
- Max Delbrueck Center for Molecular Medicine, Berlin, Germany
| | - Hans Krause
- Department of Urology, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Ahmed Magheli
- Department of Urology, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Torsten Giesecke
- Department of Anatomy, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Kerim Mutig
- Department of Anatomy, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | | | - Steven M Weldon
- Boehringer Ingelheim Pharmaceuticals, Ridgefield, Connecticut
| | - Duska Dragun
- Department of Nephrology, Charité-Universitätsmedizin Berlin, Berlin, Germany; and.,Berlin Institute of Health, Berlin, Germany
| | | | - Sebastian Bachmann
- Department of Anatomy, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Alexander Paliege
- Department of Nephrology, Charité-Universitätsmedizin Berlin, Berlin, Germany; and .,Berlin Institute of Health, Berlin, Germany
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Montford JR, Lehman AMB, Scobey MS, Weiser-Evans MCM, Nemenoff RA, Furgeson SB. Cytosolic phospholipase A 2α increases proliferation and de-differentiation of human renal tubular epithelial cells. Prostaglandins Other Lipid Mediat 2016; 126:1-8. [PMID: 27554058 DOI: 10.1016/j.prostaglandins.2016.08.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Revised: 07/14/2016] [Accepted: 08/19/2016] [Indexed: 01/03/2023]
Abstract
The group IVA calcium-dependent cytosolic phospholipase A2 (cPLA2α) enzyme controls the release of arachidonic acid from membrane bound phospholipids and is the rate-limiting step in production of eicosanoids. A variety of different kidney injuries activate cPLA2α, therefore we hypothesized that cPLA2α activity would regulate pathologic processes in HK-2 cells, a human renal tubular epithelial cell line, by regulating cell phenotype and proliferation. In two lentiviral cPLA2α-silenced knockdowns, we observed decreased proliferation and increased apoptosis compared to control HK-2 cells. cPLA2α-silenced cells also demonstrated an altered morphology, had increased expression E-cadherin, and decreased expression of Ncadherin. Increased levels of E-cadherin were associated with increased promoter activity and decreased levels of SNAIL1, SNAIL2, and ZEB1, transcriptional repressors of E-cadherin expression. Addition of exogenous arachidonic acid, but not PGE2, reversed the phenotypic changes in cPLA2α-silenced cells. These data suggest that cPLA2α may play a key role in renal repair after injury through a PGE2-independent mechanism.
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Affiliation(s)
- John R Montford
- Division of Renal Diseases and Hypertension, Department of Medicine, University of Colorado-Anschutz Medical Campus, Aurora, CO, United States.
| | - Allison M B Lehman
- Division of Renal Diseases and Hypertension, Department of Medicine, University of Colorado-Anschutz Medical Campus, Aurora, CO, United States
| | - Micah S Scobey
- Division of Renal Diseases and Hypertension, Department of Medicine, University of Colorado-Anschutz Medical Campus, Aurora, CO, United States
| | - Mary C M Weiser-Evans
- Division of Renal Diseases and Hypertension, Department of Medicine, University of Colorado-Anschutz Medical Campus, Aurora, CO, United States
| | - Raphael A Nemenoff
- Division of Renal Diseases and Hypertension, Department of Medicine, University of Colorado-Anschutz Medical Campus, Aurora, CO, United States
| | - Seth B Furgeson
- Division of Renal Diseases and Hypertension, Department of Medicine, University of Colorado-Anschutz Medical Campus, Aurora, CO, United States; Denver Health and Hospitals, Denver, CO, United States
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Shirai A, Yamazaki O, Horita S, Nakamura M, Satoh N, Yamada H, Suzuki M, Kudo A, Kawakami H, Hofmann F, Nishiyama A, Kume H, Enomoto Y, Homma Y, Seki G. Angiotensin II dose-dependently stimulates human renal proximal tubule transport by the nitric oxide/guanosine 3',5'-cyclic monophosphate pathway. J Am Soc Nephrol 2014; 25:1523-32. [PMID: 24511122 DOI: 10.1681/asn.2013060596] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Stimulation of renal proximal tubule (PT) transport by angiotensin II (Ang II) is critical for regulation of BP. Notably, in rats, mice, and rabbits, the regulation of PT sodium transport by Ang II is biphasic: transport is stimulated by picomolar to nanomolar concentrations of Ang II but inhibited by nanomolar to micromolar concentrations of Ang II. However, little is known about the effects of Ang II on human PT transport. By functional analysis with isolated PTs obtained from nephrectomy surgery, we found that Ang II induces a dose-dependent profound stimulation of human PT transport by type 1 Ang II receptor (AT1)-dependent phosphorylation of extracellular signal-regulated kinase (ERK). In PTs of wild-type mice, the nitric oxide (NO) /cGMP/cGMP-dependent kinase II (cGKII) pathway mediated the inhibitory effect of Ang II. In PTs of cGKII-deficient mice, the inhibitory effect of Ang II was lost, but activation of the NO/cGMP pathway failed to phosphorylate ERK. Conversely, in human PTs, the NO/cGMP pathway mediated the stimulatory effect of Ang II by phosphorylating ERK independently of cGKII. These contrasting responses to the NO/cGMP pathway may largely explain the different modes of PT transport regulation by Ang II, and the unopposed marked stimulation of PT transport by high intrarenal concentrations of Ang II may be an important factor in the pathogenesis of human hypertension. Additionally, the previously unrecognized stimulatory effect of the NO/cGMP pathway on PT transport may represent a human-specific therapeutic target in hypertension.
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Affiliation(s)
| | | | | | | | | | | | | | - Akihiko Kudo
- Department of Anatomy, Kyorin University School of Medicine, Tokyo, Japan
| | - Hayato Kawakami
- Department of Anatomy, Kyorin University School of Medicine, Tokyo, Japan
| | - Franz Hofmann
- Forschergruppe 923, Institut für Pharmakologie und Toxikologie der Technischen Universität München, München, Germany; and
| | - Akira Nishiyama
- Department of Pharmacology, Kagawa University, Kagawa, Japan
| | - Haruki Kume
- Urology, Faculty of Medicine, The University of Tokyo, Tokyo, Japan
| | - Yutaka Enomoto
- Urology, Faculty of Medicine, The University of Tokyo, Tokyo, Japan
| | - Yukio Homma
- Urology, Faculty of Medicine, The University of Tokyo, Tokyo, Japan
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Aiello EA, De Giusti VC. Regulation of the cardiac sodium/bicarbonate cotransporter by angiotensin II: potential Contribution to structural, ionic and electrophysiological myocardial remodelling. Curr Cardiol Rev 2013; 9:24-32. [PMID: 23116057 PMCID: PMC3584305 DOI: 10.2174/157340313805076340] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2012] [Revised: 08/15/2012] [Accepted: 09/13/2012] [Indexed: 12/15/2022] Open
Abstract
The sodium/ bicarbonate cotransporter (NBC) is, with the Na+/H+ exchanger (NHE), an important alkalinizing mechanism that maintains cellular intracellular pH (pHi). In the heart exists at least three isoforms of NBC, one that promotes the co-influx of 1 molecule of Na+ per 1molecule of HCO3-(electroneutral isoform; nNBC) and two others that generates the co-influx of 1 molecule of Na+ per 2 molecules of HCO3- (electrogenic isoforms; eNBC). In addition, the eNBC generates an anionic repolarizing current that modulate the cardiac action potential (CAP), adding to such isoforms the relevance to modulate the electrophysiological function of the heart. Angiotensin II (Ang II) is one of the main hormones that regulate cardiac physiology. The alkalinizing mechanisms (NHE and NBC) are stimulated by Ang II, increasing pHi and intracellular Na+ concentration, which indirectly, due to the stimulation of the Na+/Ca2+ exchanger (NCX) operating in the reverse form, leads to an increase in the intracellular Ca2+ concentration. Interestingly, it has been shown that Ang II exhibits an opposite effect on NBC isoforms: it activates the nNBC and inhibits the eNBC. This inhibition generates a CAP prolongation, which could directly increase the intracellular Ca2+ concentration. The regulation of the intracellular Na+ and Ca2+ concentrations is crucial for the cardiac cellular physiology, but these ions are also involved in the development of cardiac hypertrophy and the damage produced by ischemia-reperfusion, suggesting a potential role of NBC in cardiac diseases.
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Affiliation(s)
- Ernesto Alejandro Aiello
- Centro de Investigaciones Cardiovasculares, Facultad de Ciencias Médicas, Universidad Nacional de La Plata, Calle 60 y 120, 1900, La Plata, Argentina.
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