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de Los Heros P, Pacheco-Alvarez D, Gamba G. Role of WNK Kinases in the Modulation of Cell Volume. CURRENT TOPICS IN MEMBRANES 2018; 81:207-235. [PMID: 30243433 DOI: 10.1016/bs.ctm.2018.08.002] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Ion Transport across the cell membrane is required to maintain cell volume homeostasis. In response to changes in extracellular osmolarity, most cells activate specific metabolic or membrane-transport pathways to respond to cell swelling or shrinkage and return their volume to its normal resting state. This process involves the rapid adjustment of the activities of channels and transporters that mediate flux of K+, Na+, Cl-, and small organic osmolytes. Cation chloride cotransporters (CCCs) NKCCs and KCCs are a family of membrane proteins modulated by changes in cell volume and/or in the intracellular chloride concentration ([Cl-]i). Cell swelling triggers regulatory volume decrease (RVD), promoting solute and water efflux to restore normal cell volume. Swelling-activated KCCs mediate RVD in most cell types. In contrast, cell shrinkage triggers regulatory volume increase (RVI), which involves the activation of the NKCC1 cotransporter of the CCC family. Regulation of the CCCs during RVI and RVD by protein phosphorylation is a well-characterized mechanism, where WNK kinases and their downstream kinase substrates, SPAK and OSR1 constitute the essential phospho-regulators. WNKs-SPAK/OSR1-CCCs complex is required to regulate cell shrinkage-induced RVI or cell swelling-induced RVD via activating or inhibitory phosphorylation of NKCCs or KCCs, respectively. WNK1 and WNK4 kinases have been established as [Cl-]i sensors/regulators, while a role for WNK3 kinase as a cell volume-sensing kinase has emerged and is proposed in this chapter.
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Affiliation(s)
- Paola de Los Heros
- División de Investigación, Facultad de Medicina, Universidad Nacional Autónoma de México, Coyoacán, Mexico City, Mexico
| | | | - Gerardo Gamba
- Molecular Physiology Unit, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Tlalpan, Mexico City, Mexico; Department of Nephrology and Mineral Metabolism, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Tlalpan, Mexico City, Mexico
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AlAmri MA, Kadri H, Alderwick LJ, Jeeves M, Mehellou Y. The Photosensitising Clinical Agent Verteporfin Is an Inhibitor of SPAK and OSR1 Kinases. Chembiochem 2018; 19:2072-2080. [PMID: 29999233 DOI: 10.1002/cbic.201800272] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Indexed: 12/27/2022]
Abstract
STE20/SPS1-related proline/alanine-rich kinase (SPAK) and oxidative-stress-responsive kinase 1 (OSR1) are two serine/threonine protein kinases that play key roles in regulating ion homeostasis. Various SPAK and OSR1 mouse models exhibited reduced blood pressure. Herein, the discovery of verteporfin, a photosensitising agent used in photodynamic therapy, as a potent inhibitor of SPAK and OSR1 kinases is reported. It is shown that verteporfin binds the kinase domains of SPAK and OSR1 and inhibits their catalytic activity in an adenosine triphosphate (ATP)-independent manner. In cells, verteporfin was able to suppress the phosphorylation of the ion co-transporter NKCC1; a downstream physiological substrate of SPAK and OSR1 kinases. Kinase panel screening indicated that verteporfin inhibited a further eight protein kinases more potently than that of SPAK and OSR1. Although verteporfin has largely been studied as a modifier of the Hippo signalling pathway, this work indicates that the WNK-SPAK/OSR1 signalling cascade is also a target of this clinical agent. This finding could explain the fluctuation in blood pressure noted in patients and animals treated with this drug.
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Affiliation(s)
- Mubarak A AlAmri
- School of Pharmacy, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Hachemi Kadri
- School of Pharmacy and Pharmaceutical Sciences, Cardiff University, King Edward VII Avenue, Cardiff, CF10 3NB, UK
| | - Luke J Alderwick
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Mark Jeeves
- School of Cancer Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Youcef Mehellou
- School of Pharmacy and Pharmaceutical Sciences, Cardiff University, King Edward VII Avenue, Cardiff, CF10 3NB, UK
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Rodan AR. WNK-SPAK/OSR1 signaling: lessons learned from an insect renal epithelium. Am J Physiol Renal Physiol 2018; 315:F903-F907. [PMID: 29923766 DOI: 10.1152/ajprenal.00176.2018] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
WNK [with no lysine (K)] kinases regulate renal epithelial ion transport to maintain homeostasis of electrolyte concentrations, extracellular volume, and blood pressure. The SLC12 cation-chloride cotransporters, including the sodium-potassium-2-chloride (NKCC) and sodium chloride cotransporters (NCC), are targets of WNK regulation via the intermediary kinases SPAK (Ste20-related proline/alanine-rich kinase) and OSR1 (oxidative stress response). The pathway is activated by low dietary potassium intake, resulting in increased phosphorylation and activity of NCC. Chloride regulates WNK kinases in vitro by binding to the active site and inhibiting autophosphorylation and has been proposed to modulate WNK activity in the distal convoluted tubule in response to low dietary potassium. WNK-SPAK/OSR1 regulation of NKCC-dependent ion transport is evolutionarily ancient, and it occurs in the Drosophila Malpighian (renal) tubule. Here, we review recent studies from the Drosophila tubule demonstrating cooperative roles for chloride and the scaffold protein Mo25 (mouse protein-25, also known as calcium-binding protein-39) in the regulation of WNK-SPAK/OSR1 signaling in a transporting renal epithelium. Insights gained from this genetically manipulable and physiologically accessible epithelium shed light on molecular mechanisms of regulation of the WNK-SPAK/OSR1 pathway, which is important in human health and disease.
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Affiliation(s)
- Aylin R Rodan
- Department of Internal Medicine, Division of Nephrology and Hypertension, Molecular Medicine Program, University of Utah , Salt Lake City, Utah
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Dimke H, Schnermann J. Axial and cellular heterogeneity in electrolyte transport pathways along the thick ascending limb. Acta Physiol (Oxf) 2018; 223:e13057. [PMID: 29476644 DOI: 10.1111/apha.13057] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Revised: 01/27/2018] [Accepted: 02/17/2018] [Indexed: 12/21/2022]
Abstract
The thick ascending limb (TAL) extends from the border of the inner medulla to the renal cortex, thus ascending through regions with wide differences in tissue solute and electrolyte concentrations. Structural and functional differences between TAL cells in the medulla (mTAL) and the cortex (cTAL) would therefore be useful to adapt TAL transport function to a changing external fluid composition. While mechanisms common to all TAL cells play a central role in the reclamation of about 25% of the NaCl filtered by the kidney, morphological features, Na+ / K+ -ATPase activity, NKCC2 splicing and phosphorylation do vary between segments and cells. The TAL contributes to K+ homeostasis and TAL cells with high or low basolateral K+ conductances have been identified which may be involved in K+ reabsorption and secretion respectively. Although transport rates for HCO3- do not differ between mTAL and cTAL, divergent axial and cellular expression of H+ transport proteins in TAL have been documented. The reabsorption of the divalent cations Ca2+ and Mg2+ is highest in cTAL and paralleled by differences in divalent cation permeability and the expression of select claudins. Morphologically, two cell types with different cell surface phenotypes have been described that still need to be linked to specific functional characteristics. The unique external environment and its change along the longitudinal axis require an axial functional heterogeneity for the TAL to optimally participate in conserving electrolyte homeostasis. Despite substantial progress in understanding TAL function, there are still considerable knowledge gaps that are just beginning to become bridged.
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Affiliation(s)
- H. Dimke
- Department of Cardiovascular and Renal Research; Institute of Molecular Medicine; University of Southern Denmark; Odense Denmark
| | - J. Schnermann
- National Institute of Diabetes and Digestive and Kidney Diseases; Bethesda MD USA
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Trafficking and regulation of the NKCC2 cotransporter in the thick ascending limb. Curr Opin Nephrol Hypertens 2018; 26:392-397. [PMID: 28614115 DOI: 10.1097/mnh.0000000000000351] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
PURPOSE OF REVIEW The kidney Na-K-2Cl cotransporter (NKCC2) is essential for urinary concentration and renal electrolyte handling. Loss of function mutations in the NKCC2 gene cause urinary salt and potassium wasting, whereas excessive NKCC2 function has been linked to high blood pressure. Loop diuretics, targeting the transporter, are instrumental for relieving edema or hypertension. This review focuses on intrinsic mechanisms regulating NKCC2 activity at the posttranslational level, namely its trafficking and phosphorylation. RECENT FINDINGS Protein networks mediating cellular turnover of NKCC2 have recently received major attention. Several key components of its apical trafficking were identified, including respective chaperones, SNARE protein family members and raft-associated proteins. NKCC2 internalization has been characterized qualitatively and quantitatively. Kinase and phosphatase pathways regulating NKCC2 activity have been clarified and links between NKCC2 phosphorylation and trafficking proposed. Constitutive and inducible NKCC2 trafficking and phosphorylation mechanisms have been specified with focus on endocrine control of thick ascending limb (TAL) function by vasopressin. SUMMARY Proper NKCC2 trafficking and phosphorylation are critical to the TAL function in the physiological context of urinary concentration and extracellular volume regulation. Clarification of the underlying mechanisms and respective protein networks may open new therapeutic perspectives for better management of renal electrolyte disorders and blood pressure control.
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Sun Q, Wu Y, Jonusaite S, Pleinis JM, Humphreys JM, He H, Schellinger JN, Akella R, Stenesen D, Krämer H, Goldsmith EJ, Rodan AR. Intracellular Chloride and Scaffold Protein Mo25 Cooperatively Regulate Transepithelial Ion Transport through WNK Signaling in the Malpighian Tubule. J Am Soc Nephrol 2018; 29:1449-1461. [PMID: 29602832 DOI: 10.1681/asn.2017101091] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Accepted: 02/07/2018] [Indexed: 12/17/2022] Open
Abstract
Background With No Lysine kinase (WNK) signaling regulates mammalian renal epithelial ion transport to maintain electrolyte and BP homeostasis. Our previous studies showed a conserved role for WNK in the regulation of transepithelial ion transport in the Drosophila Malpighian tubule.Methods Using in vitro assays and transgenic Drosophila lines, we examined two potential WNK regulators, chloride ion and the scaffold protein mouse protein 25 (Mo25), in the stimulation of transepithelial ion flux.ResultsIn vitro, autophosphorylation of purified Drosophila WNK decreased as chloride concentration increased. In conditions in which tubule intracellular chloride concentration decreased from 30 to 15 mM as measured using a transgenic sensor, Drosophila WNK activity acutely increased. Drosophila WNK activity in tubules also increased or decreased when bath potassium concentration decreased or increased, respectively. However, a mutation that reduces chloride sensitivity of Drosophila WNK failed to alter transepithelial ion transport in 30 mM chloride. We, therefore, examined a role for Mo25. In in vitro kinase assays, Drosophila Mo25 enhanced the activity of the Drosophila WNK downstream kinase Fray, the fly homolog of mammalian Ste20-related proline/alanine-rich kinase (SPAK), and oxidative stress-responsive 1 protein (OSR1). Knockdown of Drosophila Mo25 in the Malpighian tubule decreased transepithelial ion flux under stimulated but not basal conditions. Finally, whereas overexpression of wild-type Drosophila WNK, with or without Drosophila Mo25, did not affect transepithelial ion transport, Drosophila Mo25 overexpressed with chloride-insensitive Drosophila WNK increased ion flux.Conclusions Cooperative interactions between chloride and Mo25 regulate WNK signaling in a transporting renal epithelium.
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Affiliation(s)
- Qifei Sun
- Division of Nephrology, Department of Internal Medicine and
| | - Yipin Wu
- Division of Nephrology, Department of Internal Medicine and
| | - Sima Jonusaite
- Division of Nephrology and Hypertension, Department of Internal Medicine, Molecular Medicine Program, University of Utah, Salt Lake City, Utah
| | - John M Pleinis
- Division of Nephrology and Hypertension, Department of Internal Medicine, Molecular Medicine Program, University of Utah, Salt Lake City, Utah
| | | | | | | | | | - Drew Stenesen
- Neuroscience, University of Texas Southwestern Medical Center, Dallas, Texas; and
| | - Helmut Krämer
- Neuroscience, University of Texas Southwestern Medical Center, Dallas, Texas; and
| | | | - Aylin R Rodan
- Division of Nephrology, Department of Internal Medicine and .,Division of Nephrology and Hypertension, Department of Internal Medicine, Molecular Medicine Program, University of Utah, Salt Lake City, Utah
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57
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Terker AS, Castañeda-Bueno M, Ferdaus MZ, Cornelius RJ, Erspamer KJ, Su XT, Miller LN, McCormick JA, Wang WH, Gamba G, Yang CL, Ellison DH. With no lysine kinase 4 modulates sodium potassium 2 chloride cotransporter activity in vivo. Am J Physiol Renal Physiol 2018; 315:F781-F790. [PMID: 29412704 DOI: 10.1152/ajprenal.00485.2017] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
With no lysine kinase 4 (WNK4) is essential to activate the thiazide-sensitive NaCl cotransporter (NCC) along the distal convoluted tubule, an effect central to the phenotype of familial hyperkalemic hypertension. Although effects on potassium and sodium channels along the connecting and collecting tubules have also been documented, WNK4 is typically believed to have little role in modulating sodium chloride reabsorption along the thick ascending limb of the loop of Henle. Yet wnk4-/- mice (knockout mice lacking WNK4) do not demonstrate the hypocalciuria typical of pure distal convoluted tubule dysfunction. Here, we tested the hypothesis that WNK4 also modulates bumetanide-sensitive Na-K-2Cl cotransporter (NKCC2) function along the thick ascending limb. We confirmed that w nk4-/- mice are hypokalemic and waste sodium chloride, but are also normocalciuric. Results from Western blots suggested that the phosphorylated forms of both NCC and NKCC2 were in lower abundance in wnk4-/- mice than in controls. This finding was confirmed by immunofluorescence microscopy. Although the initial response to furosemide was similar in wnk4-/- mice and controls, the response was lower in the knockout mice when reabsorption along the distal convoluted tubule was inhibited. Using HEK293 cells, we showed that WNK4 increases the abundance of phosphorylated NKCC2. More supporting evidence that WNK4 may modulate NKCC2 emerges from a mouse model of WNK4-mediated familial hyperkalemic hypertension in which more phosphorylated NKCC2 is present than in controls. These data indicate that WNK4, in addition to modulating NCC, also modulates NKCC2, contributing to its physiological function in vivo.
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Affiliation(s)
- Andrew S Terker
- Division of Nephrology & Hypertension, Department of Medicine, Oregon Health & Science University , Portland, Oregon
| | - Maria Castañeda-Bueno
- Department of Nephrology and Mineral Metabolism, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán , Mexico City, Mexico
| | - Mohammed Z Ferdaus
- Division of Nephrology & Hypertension, Department of Medicine, Oregon Health & Science University , Portland, Oregon
| | - Ryan J Cornelius
- Division of Nephrology & Hypertension, Department of Medicine, Oregon Health & Science University , Portland, Oregon
| | - Kayla J Erspamer
- Division of Nephrology & Hypertension, Department of Medicine, Oregon Health & Science University , Portland, Oregon
| | - Xiao-Tong Su
- Department of Pharmacology, New York Medical College, Valhalla, New York
| | - Lauren N Miller
- Division of Nephrology & Hypertension, Department of Medicine, Oregon Health & Science University , Portland, Oregon
| | - James A McCormick
- Division of Nephrology & Hypertension, Department of Medicine, Oregon Health & Science University , Portland, Oregon
| | - Wen-Hui Wang
- Department of Pharmacology, New York Medical College, Valhalla, New York
| | - Gerardo Gamba
- Department of Nephrology and Mineral Metabolism, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán , Mexico City, Mexico.,Molecular Physiology Unit, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma University de México , Mexico City, Mexico.,Tecnológico de Monterrey, Escuela de Medicina y de Ciencias de la Salud, Monterrey, México
| | - Chao-Ling Yang
- Division of Nephrology & Hypertension, Department of Medicine, Oregon Health & Science University , Portland, Oregon
| | - David H Ellison
- Division of Nephrology & Hypertension, Department of Medicine, Oregon Health & Science University , Portland, Oregon
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Ferdaus MZ, Miller LN, Agbor LN, Saritas T, Singer JD, Sigmund CD, McCormick JA. Mutant Cullin 3 causes familial hyperkalemic hypertension via dominant effects. JCI Insight 2017; 2:96700. [PMID: 29263298 DOI: 10.1172/jci.insight.96700] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Accepted: 11/15/2017] [Indexed: 11/17/2022] Open
Abstract
Mutations in the ubiquitin ligase scaffold protein Cullin 3 (CUL3) cause the disease familial hyperkalemic hypertension (FHHt). In the kidney, mutant CUL3 (CUL3-Δ9) increases abundance of With-No-Lysine [K] Kinase 4 (WNK4), with excessive activation of the downstream Sterile 20 (STE20)/SPS-1-related proline/alanine-rich kinase (SPAK) increasing phosphorylation of the Na+-Cl- cotransporter (NCC). CUL3-Δ9 promotes its own degradation via autoubiquitination, leading to the hypothesis that Cul3 haploinsufficiency causes FHHt. To directly test this, we generated Cul3 heterozygous mice (CUL3-Het), and Cul3 heterozygotes also expressing CUL3-Δ9 (CUL3-Het/Δ9), using an inducible renal epithelial-specific system. Endogenous CUL3 was reduced to 50% in both models, and consistent with autoubiquitination, CUL3-Δ9 protein was undetectable in CUL3-Het/Δ9 kidneys unless primary renal epithelia cells were cultured. Abundances of WNK4 and phosphorylated NCC did not differ between control and CUL3-Het mice, but they were elevated in CUL3-Het/Δ9 mice, which also displayed higher plasma [K+] and blood pressure. Abundance of phosphorylated Na+-K+-2Cl- cotransporter (NKCC2) was also increased, which may contribute to the severity of CUL3-Δ9-mediated FHHt. WNK4 and SPAK localized to puncta in NCC-positive segments but not in NKCC2-positive segments, suggesting differential effects of CUL3-Δ9. These results indicate that Cul3 haploinsufficiency does not cause FHHt, but dominant effects of CUL3-Δ9 are required.
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Affiliation(s)
- Mohammed Z Ferdaus
- Division of Nephrology & Hypertension, Department of Medicine, Oregon Health & Science University, Portland, Oregon, USA
| | - Lauren N Miller
- Division of Nephrology & Hypertension, Department of Medicine, Oregon Health & Science University, Portland, Oregon, USA
| | - Larry N Agbor
- Department of Pharmacology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Turgay Saritas
- Division of Nephrology & Hypertension, Department of Medicine, Oregon Health & Science University, Portland, Oregon, USA
| | - Jeffrey D Singer
- Department of Biology, Portland State University, Portland, Oregon, USA
| | - Curt D Sigmund
- Department of Pharmacology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA.,UIHC Center for Hypertension Research, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - James A McCormick
- Division of Nephrology & Hypertension, Department of Medicine, Oregon Health & Science University, Portland, Oregon, USA
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60
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Association between Cullin-3 Single-Nucleotide Polymorphism rs17479770 and Essential Hypertension in the Male Chinese Han Population. DISEASE MARKERS 2017; 2017:3062759. [PMID: 28804198 PMCID: PMC5540270 DOI: 10.1155/2017/3062759] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 03/25/2017] [Revised: 05/23/2017] [Accepted: 05/25/2017] [Indexed: 01/11/2023]
Abstract
Background Hypertension, including essential and secondary hypertension, is a multifactorial disease, affecting more than one billion people worldwide. Secondary hypertension can result from mutations of cullin-3 (CUL3); however, whether polymorphisms of CUL3 are associated with essential hypertension (EH) has not been reported. Here, we investigated the association between CUL3 SNPs rs17479770 and rs3738952 and EH in the Chinese Han population. Methods This case-control study investigated 520 representatives, including 259 patients with EH and 261 normotensive controls matched for age, gender, BMI, TG, TC, and HbA1c for the distribution of functional rs17479770 and rs3738952 within the CUL3 gene by using PCR and RFLP. Results Our results showed that there was no significant difference in allele and genotype distribution of rs3738952 and haplotype distribution of rs17479770 and rs3738952 between the EH group and normotensive group, whereas the rs17479770 TT genotype in male and the full data set were significantly associated with the decreased risk of EH (P = 0.050, P = 0.042), and rs17479770 allele T in male was shown to have the correlation tendency of the decreased risk of EH (P = 0.064). Conclusion Our data suggest that the CUL3 rs17479770 variant could be a protective factor in the pathogenesis of EH.
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Yamada K, Levell J, Yoon T, Kohls D, Yowe D, Rigel DF, Imase H, Yuan J, Yasoshima K, DiPetrillo K, Monovich L, Xu L, Zhu M, Kato M, Jain M, Idamakanti N, Taslimi P, Kawanami T, Argikar UA, Kunjathoor V, Xie X, Yagi YI, Iwaki Y, Robinson Z, Park HM. Optimization of Allosteric With-No-Lysine (WNK) Kinase Inhibitors and Efficacy in Rodent Hypertension Models. J Med Chem 2017; 60:7099-7107. [PMID: 28771350 DOI: 10.1021/acs.jmedchem.7b00708] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The observed structure-activity relationship of three distinct ATP noncompetitive With-No-Lysine (WNK) kinase inhibitor series, together with a crystal structure of a previously disclosed allosteric inhibitor bound to WNK1, led to an overlay hypothesis defining core and side-chain relationships across the different series. This in turn enabled an efficient optimization through scaffold morphing, resulting in compounds with a good balance of selectivity, cellular potency, and pharmacokinetic profile, which were suitable for in vivo proof-of-concept studies. When dosed orally, the optimized compound reduced blood pressure in mice overexpressing human WNK1, and induced diuresis, natriuresis and kaliuresis in spontaneously hypertensive rats (SHR), confirming that this mechanism of inhibition of WNK kinase activity is effective at regulating cardiovascular homeostasis.
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Affiliation(s)
- Ken Yamada
- Novartis Institutes for BioMedical Research, Inc. , Cambridge, Massachusetts 02139-4133, United States.,Novartis Institutes for BioMedical Research, Novartis Pharma K.K. , Tsukuba, Ibaraki 300-2611, Japan
| | - Julian Levell
- Novartis Institutes for BioMedical Research, Inc. , Cambridge, Massachusetts 02139-4133, United States
| | - Taeyong Yoon
- Novartis Institutes for BioMedical Research, Inc. , Cambridge, Massachusetts 02139-4133, United States
| | - Darcy Kohls
- Novartis Institutes for BioMedical Research, Inc. , Cambridge, Massachusetts 02139-4133, United States
| | - David Yowe
- Novartis Institutes for BioMedical Research, Inc. , Cambridge, Massachusetts 02139-4133, United States
| | - Dean F Rigel
- Novartis Institutes for BioMedical Research, Novartis Pharmaceuticals Corporation , East Hanover, New Jersey 07936-1080, United States
| | - Hidetomo Imase
- Novartis Institutes for BioMedical Research, Inc. , Cambridge, Massachusetts 02139-4133, United States
| | - Jun Yuan
- Novartis Institutes for BioMedical Research, Inc. , Cambridge, Massachusetts 02139-4133, United States
| | - Kayo Yasoshima
- Novartis Institutes for BioMedical Research, Inc. , Cambridge, Massachusetts 02139-4133, United States.,Novartis Institutes for BioMedical Research, Novartis Pharma K.K. , Tsukuba, Ibaraki 300-2611, Japan
| | - Keith DiPetrillo
- Novartis Institutes for BioMedical Research, Novartis Pharmaceuticals Corporation , East Hanover, New Jersey 07936-1080, United States
| | - Lauren Monovich
- Novartis Institutes for BioMedical Research, Inc. , Cambridge, Massachusetts 02139-4133, United States
| | - Lingfei Xu
- Novartis Institutes for BioMedical Research, Novartis Pharmaceuticals Corporation , East Hanover, New Jersey 07936-1080, United States
| | - Meicheng Zhu
- Novartis Institutes for BioMedical Research, Inc. , Cambridge, Massachusetts 02139-4133, United States
| | - Mitsunori Kato
- Novartis Institutes for BioMedical Research, Inc. , Cambridge, Massachusetts 02139-4133, United States.,Novartis Institutes for BioMedical Research, Novartis Pharma K.K. , Tsukuba, Ibaraki 300-2611, Japan
| | - Monish Jain
- Novartis Institutes for BioMedical Research, Inc. , Cambridge, Massachusetts 02139-4133, United States
| | - Neeraja Idamakanti
- Novartis Institutes for BioMedical Research, Inc. , Cambridge, Massachusetts 02139-4133, United States
| | - Paul Taslimi
- Novartis Institutes for BioMedical Research, Inc. , Cambridge, Massachusetts 02139-4133, United States
| | - Toshio Kawanami
- Novartis Institutes for BioMedical Research, Inc. , Cambridge, Massachusetts 02139-4133, United States.,Novartis Institutes for BioMedical Research, Novartis Pharma K.K. , Tsukuba, Ibaraki 300-2611, Japan
| | - Upendra A Argikar
- Novartis Institutes for BioMedical Research, Inc. , Cambridge, Massachusetts 02139-4133, United States
| | - Vidya Kunjathoor
- Novartis Institutes for BioMedical Research, Inc. , Cambridge, Massachusetts 02139-4133, United States
| | - Xiaoling Xie
- Novartis Institutes for BioMedical Research, Inc. , Cambridge, Massachusetts 02139-4133, United States
| | - Yukiko I Yagi
- Novartis Institutes for BioMedical Research, Novartis Pharma K.K. , Tsukuba, Ibaraki 300-2611, Japan
| | - Yuki Iwaki
- Novartis Institutes for BioMedical Research, Inc. , Cambridge, Massachusetts 02139-4133, United States
| | - Zachary Robinson
- Novartis Institutes for BioMedical Research, Inc. , Cambridge, Massachusetts 02139-4133, United States
| | - Hyi-Man Park
- Novartis Institutes for BioMedical Research, Inc. , Cambridge, Massachusetts 02139-4133, United States.,Novartis Institutes for BioMedical Research, Novartis Pharma K.K. , Tsukuba, Ibaraki 300-2611, Japan
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Zhang J, Karimy JK, Delpire E, Kahle KT. Pharmacological targeting of SPAK kinase in disorders of impaired epithelial transport. Expert Opin Ther Targets 2017; 21:795-804. [PMID: 28679296 PMCID: PMC6081737 DOI: 10.1080/14728222.2017.1351949] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The mammalian SPS1-related proline/alanine-rich serine-threonine kinase SPAK (STK39) modulates ion transport across and between epithelial cells in response to environmental stimuli such osmotic stress and inflammation. Research over the last decade has established a central role for SPAK in the regulation of ion and water transport in the distal nephron, colonic crypts, and pancreatic ducts, and has implicated deregulated SPAK signaling in NaCl-sensitive hypertension, ulcerative colitis and Crohn's disease, and cystic fibrosis. Areas covered: We review recent advances in our understanding of the role of SPAK kinase in the regulation of epithelial transport. We highlight how SPAK signaling - including its upstream Cl- sensitive activators, the WNK kinases, and its downstream ion transport targets, the cation- Cl- cotransporters contribute to human disease. We discuss prospects for the pharmacotherapeutic targeting of SPAK kinase in specific human disorders that feature impaired epithelial homeostasis. Expert opinion: The development of novel drugs that antagonize the SPAK-WNK interaction, inhibit SPAK kinase activity, or disrupt SPAK kinase activation by interfering with its binding to MO25α/β could be useful adjuncts in essential hypertension, inflammatory colitis, and cystic fibrosis.
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Affiliation(s)
- Jinwei Zhang
- Institute of Biomedical and Clinical Sciences, University of Exeter Medical School, Hatherly Laboratory, Exeter, EX4 4PS, UK
| | - Jason K. Karimy
- Department of Neurosurgery, Yale School of Medicine, New Haven, CT 06510, USA
| | - Eric Delpire
- Department of Anesthesiolgy, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Kristopher T. Kahle
- Departments of Neurosurgery, Pediatrics, and Cellular & Molecular Physiology; and Centers for Mendelian Genomics, Yale School of Medicine, New Haven, CT 06510, USA
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63
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Bachmann S, Mutig K. Regulation of renal Na-(K)-Cl cotransporters by vasopressin. Pflugers Arch 2017; 469:889-897. [DOI: 10.1007/s00424-017-2002-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Revised: 05/16/2017] [Accepted: 05/17/2017] [Indexed: 10/19/2022]
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64
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Abstract
WNK kinases, along with their upstream regulators (CUL3/KLHL3) and downstream targets (the SPAK/OSR1 kinases and the cation-Cl- cotransporters [CCCs]), comprise a signaling cascade essential for ion homeostasis in the kidney and nervous system. Recent work has furthered our understanding of the WNKs in epithelial transport, cell volume homeostasis, and GABA signaling, and uncovered novel roles for this pathway in immune cell function and cell proliferation.
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Affiliation(s)
- Masoud Shekarabi
- Department of Neuroscience, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA
| | - Jinwei Zhang
- Departments of Neurosurgery, Centers for Mendelian Genomics, Yale School of Medicine, New Haven, CT 06477, USA; MRC Protein Phosphorylation and Ubiquitylation Unit, College of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland, UK
| | - Arjun R Khanna
- Department of Neurosurgery, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Neurosurgery, Harvard Medical School, Boston, MA 02115, USA
| | - David H Ellison
- Division of Nephrology & Hypertension, Department of Medicine, Oregon Health & Science University, Portland, Oregon 97239, USA; VA Portland Health Care System, Portland, OR 97239, USA
| | - Eric Delpire
- Department of Anesthesiology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Kristopher T Kahle
- Departments of Neurosurgery, Pediatrics, and Cellular & Molecular Physiology, Centers for Mendelian Genomics, Yale School of Medicine, New Haven, CT 06477, USA.
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65
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Himmerkus N, Plain A, Marques RD, Sonntag SR, Paliege A, Leipziger J, Bleich M. AVP dynamically increases paracellular Na+ permeability and transcellular NaCl transport in the medullary thick ascending limb of Henle’s loop. Pflugers Arch 2016; 469:149-158. [DOI: 10.1007/s00424-016-1915-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Revised: 11/21/2016] [Accepted: 11/22/2016] [Indexed: 01/08/2023]
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66
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Lazo-Fernández Y, Baile G, Meade P, Torcal P, Martínez L, Ibañez C, Bernal ML, Viollet B, Giménez I. Kidney-specific genetic deletion of both AMPK α-subunits causes salt and water wasting. Am J Physiol Renal Physiol 2016; 312:F352-F365. [PMID: 28179232 DOI: 10.1152/ajprenal.00169.2016] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Revised: 11/07/2016] [Accepted: 11/07/2016] [Indexed: 11/22/2022] Open
Abstract
AMP-activated kinase (AMPK) controls cell energy homeostasis by modulating ATP synthesis and expenditure. In vitro studies have suggested AMPK may also control key elements of renal epithelial electrolyte transport but in vivo physiological confirmation is still insufficient. We studied sodium renal handling and extracellular volume regulation in mice with genetic deletion of AMPK catalytic subunits. AMPKα1 knockout (KO) mice exhibit normal renal sodium handling and a moderate antidiuretic state. This is accompanied by higher urinary aldosterone excretion rates and reduced blood pressure. Plasma volume, however, was found to be increased compared with wild-type mice. Thus blood volume is preserved despite a significantly lower hematocrit. The lack of a defect in renal function in AMPKα1 KO mice could be explained by a compensatory upregulation in AMPK α2-subunit. Therefore, we used the Cre-loxP system to knock down AMPKα2 expression in renal epithelial cells. Combining this approach with the systemic deletion of AMPKα1 we achieved reduced renal AMPK activity, accompanied by a shift to a moderate water- and salt-wasting phenotype. Thus we confirm the physiologically relevant role of AMPK in the kidney. Furthermore, our results indicate that in vivo AMPK activity stimulates renal sodium and water reabsorption.
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Affiliation(s)
| | - Goretti Baile
- Department of Pharmacology and Physiology, University of Zaragoza, Zaragoza, Spain
| | - Patricia Meade
- Department of Cellular Biology and Biochemistry University of Zaragoza, Zaragoza, Spain.,IIS Aragón. Instituto Aragonés de Ciencias de la Salud, Zaragoza, Spain
| | - Pilar Torcal
- IIS Aragón. Instituto Aragonés de Ciencias de la Salud, Zaragoza, Spain
| | - Laura Martínez
- IIS Aragón. Instituto Aragonés de Ciencias de la Salud, Zaragoza, Spain
| | - Carmen Ibañez
- Department of Pharmacology and Physiology, University of Zaragoza, Zaragoza, Spain
| | - Maria Luisa Bernal
- Department of Pharmacology and Physiology, University of Zaragoza, Zaragoza, Spain
| | - Benoit Viollet
- INSERM, U1016, Institut Cochin, Paris, France.,CNRS (UMR 8104), Paris, France; and.,Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Ignacio Giménez
- Department of Pharmacology and Physiology, University of Zaragoza, Zaragoza, Spain; .,IIS Aragón. Instituto Aragonés de Ciencias de la Salud, Zaragoza, Spain
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67
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Abstract
WNK (With-No-Lysine (K)) kinases are serine-threonine kinases characterized by an atypical placement of a catalytic lysine within the kinase domain. Mutations in human WNK1 or WNK4 cause an autosomal dominant syndrome of hypertension and hyperkalemia, reflecting the fact that WNK kinases are critical regulators of renal ion transport processes. Here, the role of WNKs in the regulation of ion transport processes in vertebrate and invertebrate renal function, cellular and organismal osmoregulation, and cell migration and cerebral edema will be reviewed, along with emerging literature demonstrating roles for WNKs in cardiovascular and neural development, Wnt signaling, and cancer. Conserved roles for these kinases across phyla are emphasized.
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Affiliation(s)
| | - Andreas Jenny
- Albert Einstein College of Medicine, New York, NY, United States.
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68
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Murthy M, Kurz T, O'Shaughnessy KM. ROMK expression remains unaltered in a mouse model of familial hyperkalemic hypertension caused by the CUL3Δ403-459 mutation. Physiol Rep 2016; 4:4/13/e12850. [PMID: 27378813 PMCID: PMC4945836 DOI: 10.14814/phy2.12850] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Accepted: 06/09/2016] [Indexed: 01/18/2023] Open
Abstract
Familial hyperkalemic hypertension (FHHt) is a rare inherited form of salt‐dependent hypertension caused by mutations in proteins that regulate the renal Na+‐Cl‐ cotransporter NCC. Mutations in four genes have been reported to cause FHHt including CUL3 (Cullin3) that encodes a component of a RING E3 ligase. Cullin‐3 binds to WNK kinase‐bound KLHL3 (the substrate recognition subunit of the ubiquitin ligase complex) to promote ubiquitination and proteasomal degradation of WNK kinases. Deletion of exon 9 from CUL3 (affecting residues 403‐459, CUL3Δ403‐459) causes a severe form of FHHt (PHA2E) that is recapitulated closely in a knock‐in mouse model. The loss of functionality of CUL3Δ403‐459 and secondary accumulation of WNK kinases causes substantial NCC activation. This accounts for the hypertension in FHHt but the origin of the hyperkalemia is less clear. Hence, we explored the impact of CUL3Δ403‐459 on expression of the distal secretory K channel, ROMK, both in vitro and in vivo. We found that expressing wild‐type but not the CUL3Δ403‐459 mutant form of CUL3 prevented the suppression of ROMK currents by WNK4 expressed in Xenopus oocytes. The mutant CUL3 protein was also unable to affect ROMK‐EGFP protein expression at the surface of mouse M‐1 cortical collecting duct (CCD) cells. The effects of CUL3 on ROMK expression in both oocytes and M‐1 CCD cells was reduced by addition of the neddylation inhibitor, MLN4924. This confirms that neddylation is important for CUL3 activity. Nevertheless, in our knock‐in mouse model expressing CUL3Δ403‐459 we could not show any alteration in ROMK expression by either western blotting whole kidney lysates or confocal microscopy of kidney sections. This suggests that the hyperkalemia in our knock‐in mouse and human PHA2E subjects with the CUL3Δ403‐459 mutation is not caused by reduced ROMK expression in the distal nephron.
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Affiliation(s)
- Meena Murthy
- Division of Experimental Medicine and Immunotherapeutics, Department of Medicine, University of Cambridge, Cambridge, CB2 2QQ, United Kingdom
| | - Thimo Kurz
- MRC Protein Phosphorylation and Ubiquitylation Unit, College of Life Sciences University of Dundee, Dow Street, Dundee DD15EH, Scotland, United Kingdom
| | - Kevin M O'Shaughnessy
- Division of Experimental Medicine and Immunotherapeutics, Department of Medicine, University of Cambridge, Cambridge, CB2 2QQ, United Kingdom
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69
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Bazúa-Valenti S, Castañeda-Bueno M, Gamba G. Physiological role of SLC12 family members in the kidney. Am J Physiol Renal Physiol 2016; 311:F131-44. [DOI: 10.1152/ajprenal.00071.2016] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Accepted: 04/12/2016] [Indexed: 12/30/2022] Open
Abstract
The solute carrier family 12, as numbered according to Human Genome Organisation (HUGO) nomenclature, encodes the electroneutral cation-coupled chloride cotransporters that are expressed in many cells and tissues; they play key roles in important physiological events, such as cell volume regulation, modulation of the intracellular chloride concentration, and transepithelial ion transport. Most of these family members are expressed in specific regions of the nephron. The Na-K-2Cl cotransporter NKCC2, which is located in the thick ascending limb, and the Na-Cl cotransporter, which is located in the distal convoluted tubule, play important roles in salt reabsorption and serve as the receptors for loop and thiazide diuretics, respectively (Thiazide diuretics are among the most commonly prescribed drugs in the world.). The activity of these transporters correlates with blood pressure levels; thus, their regulation has been a subject of intense research for more than a decade. The K-Cl cotransporters KCC1, KCC3, and KCC4 are expressed in several nephron segments, and their role in renal physiology is less understood but nevertheless important. Evidence suggests that they are involved in modulating proximal tubule glucose reabsorption, thick ascending limb salt reabsorption and collecting duct proton secretion. In this work, we present an overview of the physiological roles of these transporters in the kidney, with particular emphasis on the knowledge gained in the past few years.
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Affiliation(s)
- Silvana Bazúa-Valenti
- Molecular Physiology Unit, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán and Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Tlalpan, Mexico City, Mexico
| | - María Castañeda-Bueno
- Molecular Physiology Unit, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán and Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Tlalpan, Mexico City, Mexico
| | - Gerardo Gamba
- Molecular Physiology Unit, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán and Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Tlalpan, Mexico City, Mexico
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70
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Gamba G. The evolving field of salt transport regulation in the Steve Hebert Lecture. Am J Physiol Renal Physiol 2016; 311:F68-70. [PMID: 27147671 DOI: 10.1152/ajprenal.00229.2016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Affiliation(s)
- Gerardo Gamba
- Molecular Physiology Unit, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México and Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico
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71
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Mutig K, Borowski T, Boldt C, Borschewski A, Paliege A, Popova E, Bader M, Bachmann S. Demonstration of the functional impact of vasopressin signaling in the thick ascending limb by a targeted transgenic rat approach. Am J Physiol Renal Physiol 2016; 311:F411-23. [PMID: 27306979 DOI: 10.1152/ajprenal.00126.2016] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Accepted: 06/09/2016] [Indexed: 11/22/2022] Open
Abstract
The antidiuretic hormone vasopressin (AVP) regulates renal salt and water reabsorption along the distal nephron and collecting duct system. These effects are mediated by vasopressin 2 receptors (V2R) and release of intracellular Gs-mediated cAMP to activate epithelial transport proteins. Inactivating mutations in the V2R gene lead to the X-linked form of nephrogenic diabetes insipidus (NDI), which has chiefly been related with impaired aquaporin 2-mediated water reabsorption in the collecting ducts. Previous work also suggested the AVP-V2R-mediated activation of Na(+)-K(+)-2Cl(-)-cotransporters (NKCC2) along the thick ascending limb (TAL) in the context of urine concentration, but its individual contribution to NDI or, more generally, to overall renal function was unclear. We hypothesized that V2R-mediated effects in TAL essentially determine its reabsorptive function. To test this, we reevaluated V2R expression. Basolateral membranes of medullary and cortical TAL were clearly stained, whereas cells of the macula densa were unreactive. A dominant-negative, NDI-causing truncated V2R mutant (Ni3-Glu242stop) was then introduced into the rat genome under control of the Tamm-Horsfall protein promoter to cause a tissue-specific AVP-signaling defect exclusively in TAL. Resulting Ni3-V2R transgenic rats revealed decreased basolateral but increased intracellular V2R signal in TAL epithelia, suggesting impaired trafficking of the receptor. Rats displayed significant baseline polyuria, failure to concentrate the urine in response to water deprivation, and hypercalciuria. NKCC2 abundance, phosphorylation, and surface expression were markedly decreased. In summary, these data indicate that suppression of AVP-V2R signaling in TAL causes major impairment in renal fluid and electrolyte handling. Our results may have clinical implications.
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Affiliation(s)
- Kerim Mutig
- Department of Anatomy, Charité Universitätsmedizin, Berlin, Germany; and
| | - Tordis Borowski
- Department of Anatomy, Charité Universitätsmedizin, Berlin, Germany; and
| | - Christin Boldt
- Department of Anatomy, Charité Universitätsmedizin, Berlin, Germany; and
| | - Aljona Borschewski
- Department of Anatomy, Charité Universitätsmedizin, Berlin, Germany; and
| | - Alexander Paliege
- Department of Anatomy, Charité Universitätsmedizin, Berlin, Germany; and
| | - Elena Popova
- Max-Delbrück-Center for Molecular Medicine, Berlin, Germany
| | - Michael Bader
- Max-Delbrück-Center for Molecular Medicine, Berlin, Germany
| | - Sebastian Bachmann
- Department of Anatomy, Charité Universitätsmedizin, Berlin, Germany; and
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72
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Ferdaus MZ, Barber KW, López-Cayuqueo KI, Terker AS, Argaiz ER, Gassaway BM, Chambrey R, Gamba G, Rinehart J, McCormick JA. SPAK and OSR1 play essential roles in potassium homeostasis through actions on the distal convoluted tubule. J Physiol 2016; 594:4945-66. [PMID: 27068441 DOI: 10.1113/jp272311] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Accepted: 04/07/2016] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS STE20 (Sterile 20)/SPS-1 related proline/alanine-rich kinase (SPAK) and oxidative stress-response kinase-1 (OSR1) phosphorylate and activate the renal Na(+) -K(+) -2Cl(-) cotransporter 2 (NKCC2) and Na(+) Cl(-) cotransporter (NCC). Mouse models suggest that OSR1 mainly activates NKCC2-mediated sodium transport along the thick ascending limb, while SPAK mainly activates NCC along the distal convoluted tubule, but the kinases may compensate for each other. We hypothesized that disruption of both kinases would lead to polyuria and severe salt-wasting, and generated SPAK/OSR1 double knockout mice to test this. Despite a lack of SPAK and OSR1, phosphorylated NKCC2 abundance was still high, suggesting the existence of an alternative activating kinase. Compensatory changes in SPAK/OSR1-independent phosphorylation sites on both NKCC2 and NCC and changes in sodium transport along the collecting duct were also observed. Potassium restriction revealed that SPAK and OSR1 play essential roles in the emerging model that NCC activation is central to sensing changes in plasma [K(+) ]. ABSTRACT STE20 (Sterile 20)/SPS-1 related proline/alanine-rich kinase (SPAK) and oxidative stress-response kinase-1 (OSR1) activate the renal cation cotransporters Na(+) -K(+) -2Cl(-) cotransporter (NKCC2) and Na(+) -Cl(-) cotransporter (NCC) via phosphorylation. Knockout mouse models suggest that OSR1 mainly activates NKCC2, while SPAK mainly activates NCC, with possible cross-compensation. We tested the hypothesis that disrupting both kinases causes severe polyuria and salt-wasting by generating SPAK/OSR1 double knockout (DKO) mice. DKO mice displayed lower systolic blood pressure compared with SPAK knockout (SPAK-KO) mice, but displayed no severe phenotype even after dietary salt restriction. Phosphorylation of NKCC2 at SPAK/OSR1-dependent sites was lower than in SPAK-KO mice, but still significantly greater than in wild type mice. In the renal medulla, there was significant phosphorylation of NKCC2 at SPAK/OSR1-dependent sites despite a complete absence of SPAK and OSR1, suggesting the existence of an alternative activating kinase. The distal convoluted tubule has been proposed to sense plasma [K(+) ], with NCC activation serving as the primary effector pathway that modulates K(+) secretion, by metering sodium delivery to the collecting duct. Abundance of phosphorylated NCC (pNCC) is dramatically lower in SPAK-KO mice than in wild type mice, and the additional disruption of OSR1 further reduced pNCC. SPAK-KO and kidney-specific OSR1 single knockout mice maintained plasma [K(+) ] following dietary potassium restriction, but DKO mice developed severe hypokalaemia. Unlike mice lacking SPAK or OSR1 alone, DKO mice displayed an inability to phosphorylate NCC under these conditions. These data suggest that SPAK and OSR1 are essential components of the effector pathway that maintains plasma [K(+) ].
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Affiliation(s)
- Mohammed Z Ferdaus
- Division of Nephrology & Hypertension, Department of Medicine, Oregon Health & Science University, Portland, OR, 97239, USA
| | - Karl W Barber
- Department of Cellular & Molecular Physiology, Yale University, New Haven, CT, 06520, USA.,Systems Biology Institute, Yale University, Orange, CT, 06477, USA
| | - Karen I López-Cayuqueo
- INSERM U970, Paris Cardiovascular Research Center, Université Paris-Descartes, Paris, France
| | - Andrew S Terker
- Division of Nephrology & Hypertension, Department of Medicine, Oregon Health & Science University, Portland, OR, 97239, USA
| | - Eduardo R Argaiz
- Molecular Physiology Unit, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México and Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico
| | - Brandon M Gassaway
- Department of Cellular & Molecular Physiology, Yale University, New Haven, CT, 06520, USA.,Systems Biology Institute, Yale University, Orange, CT, 06477, USA
| | - Régine Chambrey
- INSERM U970, Paris Cardiovascular Research Center, Université Paris-Descartes, Paris, France
| | - Gerardo Gamba
- Molecular Physiology Unit, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México and Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico
| | - Jesse Rinehart
- Department of Cellular & Molecular Physiology, Yale University, New Haven, CT, 06520, USA.,Systems Biology Institute, Yale University, Orange, CT, 06477, USA
| | - James A McCormick
- Division of Nephrology & Hypertension, Department of Medicine, Oregon Health & Science University, Portland, OR, 97239, USA
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73
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Abstract
PURPOSE OF REVIEW Transepithelial salt transport in the thick ascending limb of Henle's loop (TAL) crucially depends on the activity of the Na/K/2Cl cotransporter NKCC2. The pharmacologic blockade of NKCC2 leads to pronounced natriuresis and diuresis, which indicate key roles for NKCC2 in renal salt retrieval. The inadequate regulation of NKCC2 and the loss of NKCC2 function are associated with the disruption of salt and water homoeostasis. This review provides a specific overview of our current knowledge with respect to the regulation of NKCC2 by differential splicing and phosphorylation. RECENT FINDINGS Several mechanisms have evolved to adapt NKCC2 transport to reabsorptive needs. These mechanisms include the regulation of NKCC2 gene expression, the differential splicing of the NKCC2 pre-mRNA, the membrane trafficking, and the modulation of the specific transport activity. Substantial progress has been made over the past few years in deciphering the function of kinases in the regulatory network controlling NKCC2 activity and in elucidating the underlying mechanism and the functional consequences of the regulated differential splicing of the NKCC2 pre-mRNA. SUMMARY NKCC2 differential splicing and phosphorylation are critically involved in the modulation of the thick ascending limb of Henle's loop reabsorptive capacity and, consequently, in salt homoeostasis, volume regulation, and blood pressure control.
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74
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Ferdaus MZ, McCormick JA. The CUL3/KLHL3-WNK-SPAK/OSR1 pathway as a target for antihypertensive therapy. Am J Physiol Renal Physiol 2016; 310:F1389-96. [PMID: 27076645 DOI: 10.1152/ajprenal.00132.2016] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Accepted: 04/07/2016] [Indexed: 01/11/2023] Open
Abstract
Chronic high blood pressure (hypertension) is the most common disease in the Unites States. While several classes of drugs exist to treat it, many patients (up to 10 million Americans) respond poorly to therapy, even when multiple classes are used. Recent evidence suggests that a significant portion of patients will always remain hypertensive despite maximum therapy with the drugs currently available. Therefore, there is a pressing need to develop novel antihypertensive agents. One limitation has been the identification of new targets, a limitation that has been overcome by recent insights into the mechanisms underlying monogenic forms of hypertension. The disease familial hyperkalemic hypertension is caused by mutations in with-no-lysine (WNK) kinases 1 and 4 and in cullin-3 and kelch-like 3, components of an E3 ubiquitin ligase complex that promotes WNK kinase degradation. The study of the mechanisms by which this pathway regulates blood pressure has identified several candidates for the development of new antihypertensive agents. This pathway is particularly attractive since its inhibition may not only reduce renal sodium reabsorption along multiple segments but may also reduce vascular tone. Here, we will describe the mechanisms by which this pathway regulate blood pressure and discuss the potential of targeting it to develop new antihypertensive drugs.
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Affiliation(s)
- Mohammed Z Ferdaus
- Division of Nephrology and Hypertension, Department of Medicine, Oregon Health and Science University, Portland, Oregon
| | - James A McCormick
- Division of Nephrology and Hypertension, Department of Medicine, Oregon Health and Science University, Portland, Oregon
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75
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Salomon JJ, Spahn S, Wang X, Füllekrug J, Bertrand CA, Mall MA. Generation and functional characterization of epithelial cells with stable expression of SLC26A9 Cl- channels. Am J Physiol Lung Cell Mol Physiol 2016; 310:L593-602. [PMID: 26801567 DOI: 10.1152/ajplung.00321.2015] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Accepted: 01/16/2016] [Indexed: 01/01/2023] Open
Abstract
Recent studies identified the SLC26A9 Cl(-) channel as a modifier and potential therapeutic target in cystic fibrosis (CF). However, understanding of the regulation of SLC26A9 in epithelia remains limited and cellular models with stable expression for biochemical and functional studies are missing. We, therefore, generated Fisher rat thyroid (FRT) epithelial cells with stable expression of HA-tagged SLC26A9 via retroviral transfection and characterized SLC26A9 expression and function using Western blotting, immunolocalization, whole cell patch-clamp, and transepithelial bioelectric studies in Ussing chambers. We demonstrate stable expression of SLC26A9 in transfected FRT (SLC26A9-FRT) cells on the mRNA and protein level. Immunolocalization and Western blotting detected SLC26A9 in different intracellular compartments and to a lesser extent at the cell surface. Whole cell patch-clamp recordings demonstrated significantly increased constitutive Cl(-) currents in SLC26A9-FRT compared with control-transduced FRT (Control-FRT) cells (P < 0.01). Similar, transepithelial measurements showed that the basal short circuit current was significantly increased in SLC26A9-FRT vs. Control-FRT cell monolayers (P < 0.01). SLC26A9-mediated Cl(-) currents were increased by cAMP-dependent stimulation (IBMX and forskolin) and inhibited by GlyH-101, niflumic acid, DIDS, and 5-nitro-2-(3-phenylpropylamino) benzoic acid (NPPB), as well as RNAi knockdown of WNK1 implicated in epithelial osmoregulation. Our results support that these novel epithelial cells with stable expression of SLC26A9 will be a useful model for studies of pharmacological regulation including the identification of activators of SLC26A9 Cl(-) channels that may compensate deficient cystic fibrosis transmembrane regulator (CFTR)-mediated Cl(-) secretion and serve as an alternative therapeutic target in patients with CF and potentially other muco-obstructive lung diseases.
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Affiliation(s)
- Johanna J Salomon
- Department of Translational Pulmonology, Translational Lung Research Center Heidelberg (TLRC), Member of the German Center for Lung Research (DZL), University of Heidelberg, Heidelberg, Germany
| | - Stephan Spahn
- Department of Translational Pulmonology, Translational Lung Research Center Heidelberg (TLRC), Member of the German Center for Lung Research (DZL), University of Heidelberg, Heidelberg, Germany
| | - Xiaohui Wang
- Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania; and
| | - Joachim Füllekrug
- Molecular Cell Biology Laboratory, Department of Internal Medicine IV, University of Heidelberg, Heidelberg, Germany
| | - Carol A Bertrand
- Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania; and
| | - Marcus A Mall
- Department of Translational Pulmonology, Translational Lung Research Center Heidelberg (TLRC), Member of the German Center for Lung Research (DZL), University of Heidelberg, Heidelberg, Germany;
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76
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Osmotic stress induces the phosphorylation of WNK4 Ser575 via the p38MAPK-MK pathway. Sci Rep 2016; 6:18710. [PMID: 26732173 PMCID: PMC4702109 DOI: 10.1038/srep18710] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2015] [Accepted: 11/23/2015] [Indexed: 12/24/2022] Open
Abstract
The With No lysine [K] (WNK)-Ste20-related proline/alanine-rich kinase (SPAK)/oxidative stress-responsive kinase 1 (OSR1) pathway has been reported to be a crucial signaling pathway for triggering pseudohypoaldosteronism type II (PHAII), an autosomal dominant hereditary disease that is characterized by hypertension. However, the molecular mechanism(s) by which the WNK-SPAK/OSR1 pathway is regulated remain unclear. In this report, we identified WNK4 as an interacting partner of a recently identified MAP3K, apoptosis signal-regulating kinase 3 (ASK3). We found that WNK4 is phosphorylated in an ASK3 kinase activity-dependent manner. By exploring the ASK3-dependent phosphorylation sites, we identified Ser575 as a novel phosphorylation site in WNK4 by LC-MS/MS analysis. ASK3-dependent WNK4 Ser575 phosphorylation was mediated by the p38MAPK-MAPK-activated protein kinase (MK) pathway. Osmotic stress, as well as hypotonic low-chloride stimulation, increased WNK4 Ser575 phosphorylation via the p38MAPK-MK pathway. ASK3 was required for the p38MAPK activation induced by hypotonic stimulation but was not required for that induced by hypertonic stimulation or hypotonic low-chloride stimulation. Our results suggest that the p38MAPK-MK pathway might regulate WNK4 in an osmotic stress-dependent manner but its upstream regulators might be divergent depending on the types of osmotic stimuli.
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Li C, Zhou X, Han W, Jiang X, Liu J, Fang L, Wang H, Guan Q, Gao L, Zhao J, Xu J, Xu C. Identification of two novel mutations in SLC12A3 gene in two Chinese pedigrees with Gitelman syndrome and review of literature. Clin Endocrinol (Oxf) 2015; 83:985-93. [PMID: 25990047 DOI: 10.1111/cen.12820] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Revised: 03/19/2015] [Accepted: 05/13/2015] [Indexed: 12/13/2022]
Abstract
OBJECTIVE Gitelman syndrome (GS) is one of the most common causes of inherited hypokalaemia. As it was caused by mutations in the SLC12A3 gene, GS is a highly heterogeneous disease. Here, we aimed to investigate the clinical and genetic characteristics of two Chinese pedigrees and summarize the advance in GS genetics, diagnosis and management. SUBJECTS AND METHODS Two three-generation families with GS were identified and screened for mutations in the SLC12A3 gene. Genotype-phenotype correlations were analysed. RESULTS The two probands (A and B) were characterized by hypokalaemia, hypomagnesaemia and hypocalciuria without hypertension. Complete DNA sequencing of the SLC12A3 gene revealed two novel compound heterozygous mutations (c.179C>T and c.234delG; c.486-490delTACGGinsA and c.1925G>A), which are predicted to drastically affect normal protein structure. The female members of the pedigrees showed mild-to-no phenotype, although they carried the same mutations as the probands. Moreover, proband B presented with more severe symptoms than did proband A, which might be related to a lower serum magnesium level. During the 1-year follow-up, both probands showed satisfactory symptom improvement following the use of potassium and magnesium supplements. CONCLUSION Our findings strongly suggested that the two novel mutations in the SLC12A3 gene are the causative agents of GS, which may provide further insights into the function of this gene and help clinicians better understand this disorder.
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Affiliation(s)
- Congcong Li
- Department of Endocrinology, Shandong Provincial Hospital affiliated to Shandong University, Jinan, Shandong, China
- Institute of Endocrinology and Metabolism, Shandong Academy of Clinical Medicine, Jinan, Shandong, China
- Shandong Clinical Medical Center of Endocrinology and Metabolism, Jinan, Shandong, China
| | - Xinli Zhou
- Department of Endocrinology, Shandong Provincial Hospital affiliated to Shandong University, Jinan, Shandong, China
- Institute of Endocrinology and Metabolism, Shandong Academy of Clinical Medicine, Jinan, Shandong, China
- Shandong Clinical Medical Center of Endocrinology and Metabolism, Jinan, Shandong, China
| | - Wenxia Han
- Department of Endocrinology, Shandong Provincial Hospital affiliated to Shandong University, Jinan, Shandong, China
- Institute of Endocrinology and Metabolism, Shandong Academy of Clinical Medicine, Jinan, Shandong, China
- Shandong Clinical Medical Center of Endocrinology and Metabolism, Jinan, Shandong, China
| | - Xiuyun Jiang
- Department of Endocrinology, Shandong Provincial Hospital affiliated to Shandong University, Jinan, Shandong, China
- Institute of Endocrinology and Metabolism, Shandong Academy of Clinical Medicine, Jinan, Shandong, China
- Shandong Clinical Medical Center of Endocrinology and Metabolism, Jinan, Shandong, China
| | - Jia Liu
- Department of Endocrinology, Shandong Provincial Hospital affiliated to Shandong University, Jinan, Shandong, China
- Institute of Endocrinology and Metabolism, Shandong Academy of Clinical Medicine, Jinan, Shandong, China
- Shandong Clinical Medical Center of Endocrinology and Metabolism, Jinan, Shandong, China
| | - Li Fang
- Department of Endocrinology, Shandong Provincial Hospital affiliated to Shandong University, Jinan, Shandong, China
- Institute of Endocrinology and Metabolism, Shandong Academy of Clinical Medicine, Jinan, Shandong, China
- Shandong Clinical Medical Center of Endocrinology and Metabolism, Jinan, Shandong, China
| | - Hai Wang
- Department of Endocrinology, Shandong Provincial Hospital affiliated to Shandong University, Jinan, Shandong, China
- Institute of Endocrinology and Metabolism, Shandong Academy of Clinical Medicine, Jinan, Shandong, China
- Shandong Clinical Medical Center of Endocrinology and Metabolism, Jinan, Shandong, China
| | - Qingbo Guan
- Department of Endocrinology, Shandong Provincial Hospital affiliated to Shandong University, Jinan, Shandong, China
- Institute of Endocrinology and Metabolism, Shandong Academy of Clinical Medicine, Jinan, Shandong, China
- Shandong Clinical Medical Center of Endocrinology and Metabolism, Jinan, Shandong, China
| | - Ling Gao
- Institute of Endocrinology and Metabolism, Shandong Academy of Clinical Medicine, Jinan, Shandong, China
- Shandong Clinical Medical Center of Endocrinology and Metabolism, Jinan, Shandong, China
- Scientific Center, Shandong Provincial Hospital affiliated to Shandong University, Jinan, Shandong, China
| | - Jiajun Zhao
- Department of Endocrinology, Shandong Provincial Hospital affiliated to Shandong University, Jinan, Shandong, China
- Institute of Endocrinology and Metabolism, Shandong Academy of Clinical Medicine, Jinan, Shandong, China
- Shandong Clinical Medical Center of Endocrinology and Metabolism, Jinan, Shandong, China
| | - Jin Xu
- Department of Endocrinology, Shandong Provincial Hospital affiliated to Shandong University, Jinan, Shandong, China
- Institute of Endocrinology and Metabolism, Shandong Academy of Clinical Medicine, Jinan, Shandong, China
- Shandong Clinical Medical Center of Endocrinology and Metabolism, Jinan, Shandong, China
| | - Chao Xu
- Department of Endocrinology, Shandong Provincial Hospital affiliated to Shandong University, Jinan, Shandong, China
- Institute of Endocrinology and Metabolism, Shandong Academy of Clinical Medicine, Jinan, Shandong, China
- Shandong Clinical Medical Center of Endocrinology and Metabolism, Jinan, Shandong, China
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Fezai M, Elvira B, Warsi J, Ben-Attia M, Hosseinzadeh Z, Lang F. Up-Regulation of Intestinal Phosphate Transporter NaPi-IIb (SLC34A2) by the Kinases SPAK and OSR1. Kidney Blood Press Res 2015; 40:555-64. [PMID: 26506223 DOI: 10.1159/000368531] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/30/2015] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND/AIMS SPAK (SPS1-related proline/alanine-rich kinase) and OSR1 (oxidative stress-responsive kinase 1), kinases controlled by WNK (with-no-K[Lys] kinase), are powerful regulators of cellular ion transport and blood pressure. Observations in gene-targeted mice disclosed an impact of SPAK/OSR1 on phosphate metabolism. The present study thus tested whether SPAK and/or OSR1 contributes to the regulation of the intestinal Na(+)-coupled phosphate co-transporter NaPi-IIb (SLC34A2). METHODS cRNA encoding NaPi-IIb was injected into Xenopus laevis oocytes without or with additional injection of cRNA encoding wild-type SPAK, constitutively active (T233E)SPAK, WNK insensitive (T233A)SPAK, catalytically inactive (D212A)SPAK, wild-type OSR1, constitutively active (T185E)OSR1, WNK insensitive (T185A)OSR1 or catalytically inactive (D164A)OSR1. The phosphate (1 mM)-induced inward current (I(Pi)) was taken as measure of phosphate transport. RESULTS I(Pi) was observed in NaPi-IIb expressing oocytes but not in water injected oocytes, and was significantly increased by co-expression of SPAK, (T233E)SPAK, OSR1, (T185E)OSR1 or SPAK+OSR1, but not by co-expression of (T233A)SPAK, (D212A)SPAK, (T185A)OSR1, or (D164A)OSR1. SPAK and OSR1 both increased the maximal transport rate of the carrier. CONCLUSIONS SPAK and OSR1 are powerful stimulators of the intestinal Na+-coupled phosphate co-transporter NaPi-IIb.
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Affiliation(s)
- Myriam Fezai
- Department of Physiology I, University of Tx00FC;bingen, Tx00FC;bingen, Germany
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79
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Schumacher FR, Siew K, Zhang J, Johnson C, Wood N, Cleary SE, Al Maskari RS, Ferryman JT, Hardege I, Yasmin, Figg NL, Enchev R, Knebel A, O'Shaughnessy KM, Kurz T. Characterisation of the Cullin-3 mutation that causes a severe form of familial hypertension and hyperkalaemia. EMBO Mol Med 2015; 7:1285-306. [PMID: 26286618 PMCID: PMC4604684 DOI: 10.15252/emmm.201505444] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Deletion of exon 9 from Cullin-3 (CUL3, residues 403-459: CUL3(Δ403-459)) causes pseudohypoaldosteronism type IIE (PHA2E), a severe form of familial hyperkalaemia and hypertension (FHHt). CUL3 binds the RING protein RBX1 and various substrate adaptors to form Cullin-RING-ubiquitin-ligase complexes. Bound to KLHL3, CUL3-RBX1 ubiquitylates WNK kinases, promoting their ubiquitin-mediated proteasomal degradation. Since WNK kinases activate Na/Cl co-transporters to promote salt retention, CUL3 regulates blood pressure. Mutations in both KLHL3 and WNK kinases cause PHA2 by disrupting Cullin-RING-ligase formation. We report here that the PHA2E mutant, CUL3(Δ403-459), is severely compromised in its ability to ubiquitylate WNKs, possibly due to altered structural flexibility. Instead, CUL3(Δ403-459) auto-ubiquitylates and loses interaction with two important Cullin regulators: the COP9-signalosome and CAND1. A novel knock-in mouse model of CUL3(WT) (/Δ403-459) closely recapitulates the human PHA2E phenotype. These mice also show changes in the arterial pulse waveform, suggesting a vascular contribution to their hypertension not reported in previous FHHt models. These findings may explain the severity of the FHHt phenotype caused by CUL3 mutations compared to those reported in KLHL3 or WNK kinases.
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Affiliation(s)
- Frances-Rose Schumacher
- MRC Protein Phosphorylation and Ubiquitylation Unit, College of Life Sciences, University of Dundee, Dundee, UK
| | - Keith Siew
- Division of Experimental Medicine and Immunotherapeutics, University of Cambridge, Cambridge, UK
| | - Jinwei Zhang
- MRC Protein Phosphorylation and Ubiquitylation Unit, College of Life Sciences, University of Dundee, Dundee, UK
| | - Clare Johnson
- MRC Protein Phosphorylation and Ubiquitylation Unit, College of Life Sciences, University of Dundee, Dundee, UK
| | - Nicola Wood
- MRC Protein Phosphorylation and Ubiquitylation Unit, College of Life Sciences, University of Dundee, Dundee, UK
| | - Sarah E Cleary
- Division of Experimental Medicine and Immunotherapeutics, University of Cambridge, Cambridge, UK
| | - Raya S Al Maskari
- Division of Experimental Medicine and Immunotherapeutics, University of Cambridge, Cambridge, UK
| | - James T Ferryman
- Division of Experimental Medicine and Immunotherapeutics, University of Cambridge, Cambridge, UK
| | - Iris Hardege
- Division of Experimental Medicine and Immunotherapeutics, University of Cambridge, Cambridge, UK
| | - Yasmin
- Division of Experimental Medicine and Immunotherapeutics, University of Cambridge, Cambridge, UK
| | - Nichola L Figg
- Division of Cardiovascular Medicine, Department of Medicine, University of Cambridge, Cambridge, UK
| | | | - Axel Knebel
- MRC Protein Phosphorylation and Ubiquitylation Unit, College of Life Sciences, University of Dundee, Dundee, UK
| | - Kevin M O'Shaughnessy
- Division of Experimental Medicine and Immunotherapeutics, University of Cambridge, Cambridge, UK
| | - Thimo Kurz
- MRC Protein Phosphorylation and Ubiquitylation Unit, College of Life Sciences, University of Dundee, Dundee, UK
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80
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Nguyen MTX, Han J, Ralph DL, Veiras LC, McDonough AA. Short-term nonpressor angiotensin II infusion stimulates sodium transporters in proximal tubule and distal nephron. Physiol Rep 2015; 3:3/9/e12496. [PMID: 26347505 PMCID: PMC4600373 DOI: 10.14814/phy2.12496] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
In Sprague Dawley rats, 2-week angiotensin II (AngII) infusion increases Na+ transporter abundance and activation from cortical thick ascending loop of Henle (TALH) to medullary collecting duct (CD) and raises blood pressure associated with a pressure natriuresis, accompanied by depressed Na+ transporter abundance and activation from proximal tubule (PT) through medullary TALH. This study tests the hypothesis that early during AngII infusion, before blood pressure raises, Na+ transporters’ abundance and activation increase all along the nephron. Male Sprague Dawley rats were infused via osmotic minipumps with a subpressor dose of AngII (200 ng/kg/min) or vehicle for 3 days. Overnight urine was collected in metabolic cages and sodium transporters’ abundance and phosphorylation were determined by immunoblotting homogenates of renal cortex and medulla. There were no significant differences in body weight gain, overnight urine volume, urinary Na+ and K+ excretion, or rate of excretion of a saline challenge between AngII and vehicle infused rats. The 3-day nonpressor AngII infusion significantly increased the abundance of PT Na+/H+ exchanger 3 (NHE3), cortical TALH Na-K-2Cl cotransporter 2 (NKCC2), distal convoluted tubule (DCT) Na-Cl cotransporter (NCC), and cortical CD ENaC subunits. Additionally, phosphorylation of cortical NKCC2, NCC, and STE20/SPS1-related proline–alanine-rich kinase (SPAK) were increased; medullary NKCC2 and SPAK were not altered. In conclusion, 3-day AngII infusion provokes PT NHE3 accumulation as well as NKCC2, NCC, and SPAK accumulation and activation in a prehypertensive phase before evidence for intrarenal angiotensinogen accumulation.
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Affiliation(s)
- Mien T X Nguyen
- Department of Cell and Neurobiology, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
| | - Jiyang Han
- Department of Cell and Neurobiology, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
| | - Donna L Ralph
- Department of Cell and Neurobiology, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
| | - Luciana C Veiras
- Department of Cell and Neurobiology, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
| | - Alicia A McDonough
- Department of Cell and Neurobiology, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
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81
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Zhang J, Siew K, Macartney T, O'Shaughnessy KM, Alessi DR. Critical role of the SPAK protein kinase CCT domain in controlling blood pressure. Hum Mol Genet 2015; 24:4545-58. [PMID: 25994507 PMCID: PMC4512625 DOI: 10.1093/hmg/ddv185] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2015] [Accepted: 05/14/2015] [Indexed: 02/05/2023] Open
Abstract
The STE20/SPS1-related proline/alanine-rich kinase (SPAK) controls blood pressure (BP) by phosphorylating and stimulating the Na-Cl (NCC) and Na-K-2Cl (NKCC2) co-transporters, which regulate salt reabsorption in the kidney. SPAK possesses a conserved carboxy-terminal (CCT) domain, which recognises RFXV/I motifs present in its upstream activator [isoforms of the With-No-lysine (K) kinases (WNKs)] as well as its substrates (NCC and NKCC2). To define the physiological importance of the CCT domain, we generated knock-in mice in which the critical CCT domain Leu502 residue required for high affinity recognition of the RFXI/V motif was mutated to Alanine. The SPAK CCT domain defective knock-in animals are viable, and the Leu502Ala mutation abolished co-immunoprecipitation of SPAK with WNK1, NCC and NKCC2. The CCT domain defective animals displayed markedly reduced SPAK activity and phosphorylation of NCC and NKCC2 co-transporters at the residues phosphorylated by SPAK. This was also accompanied by a reduction in the expression of NCC and NKCC2 protein without changes in mRNA levels. The SPAK CCT domain knock-in mice showed typical features of Gitelman Syndrome with mild hypokalaemia, hypomagnesaemia, hypocalciuria and displayed salt wasting on switching to a low-Na diet. These observations establish that the CCT domain plays a crucial role in controlling SPAK activity and BP. Our results indicate that CCT domain inhibitors would be effective at reducing BP by lowering phosphorylation as well as expression of NCC and NKCC2.
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Affiliation(s)
- Jinwei Zhang
- MRC Protein Phosphorylation and Ubiquitylation Unit, College of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, Scotland and
| | - Keith Siew
- Experimental Medicine and Immunotherapeutics, Department of Medicine, University of Cambridge, Cambridge, UK
| | - Thomas Macartney
- MRC Protein Phosphorylation and Ubiquitylation Unit, College of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, Scotland and
| | - Kevin M O'Shaughnessy
- Experimental Medicine and Immunotherapeutics, Department of Medicine, University of Cambridge, Cambridge, UK
| | - Dario R Alessi
- MRC Protein Phosphorylation and Ubiquitylation Unit, College of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, Scotland and
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Kortenoeven MLA, Pedersen NB, Rosenbaek LL, Fenton RA. Vasopressin regulation of sodium transport in the distal nephron and collecting duct. Am J Physiol Renal Physiol 2015; 309:F280-99. [DOI: 10.1152/ajprenal.00093.2015] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Accepted: 05/27/2015] [Indexed: 12/22/2022] Open
Abstract
Arginine vasopressin (AVP) is released from the posterior pituitary gland during states of hyperosmolality or hypovolemia. AVP is a peptide hormone, with antidiuretic and antinatriuretic properties. It allows the kidneys to increase body water retention predominantly by increasing the cell surface expression of aquaporin water channels in the collecting duct alongside increasing the osmotic driving forces for water reabsorption. The antinatriuretic effects of AVP are mediated by the regulation of sodium transport throughout the distal nephron, from the thick ascending limb through to the collecting duct, which in turn partially facilitates osmotic movement of water. In this review, we will discuss the regulatory role of AVP in sodium transport and summarize the effects of AVP on various molecular targets, including the sodium-potassium-chloride cotransporter NKCC2, the thiazide-sensitive sodium-chloride cotransporter NCC, and the epithelial sodium channel ENaC.
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Affiliation(s)
- M. L. A. Kortenoeven
- Department of Biomedicine and Center for Interactions of Proteins in Epithelial Transport (InterPrET), Aarhus University, Aarhus, Denmark
| | - N. B. Pedersen
- Department of Biology, Faculty of Science, University of Copenhagen, Copenhagen, Denmark; and
| | - L. L. Rosenbaek
- Department of Cellular and Molecular Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - R. A. Fenton
- Department of Biomedicine and Center for Interactions of Proteins in Epithelial Transport (InterPrET), Aarhus University, Aarhus, Denmark
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Abousaab A, Warsi J, Elvira B, Alesutan I, Hoseinzadeh Z, Lang F. Down-Regulation of Excitatory Amino Acid Transporters EAAT1 and EAAT2 by the Kinases SPAK and OSR1. J Membr Biol 2015; 248:1107-19. [PMID: 26233565 DOI: 10.1007/s00232-015-9826-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Accepted: 07/24/2015] [Indexed: 11/27/2022]
Abstract
SPAK (SPS1-related proline/alanine-rich kinase) and OSR1 (oxidative stress-responsive kinase 1) are cell volume-sensitive kinases regulated by WNK (with-no-K[Lys]) kinases. SPAK/OSR1 regulate several channels and carriers. SPAK/OSR1 sensitive functions include neuronal excitability. Orchestration of neuronal excitation involves the excitatory glutamate transporters EAAT1 and EAAT2. Sensitivity of those carriers to SPAK/OSR1 has never been shown. The present study thus explored whether SPAK and/or OSR1 contribute to the regulation of EAAT1 and/or EAAT2. To this end, cRNA encoding EAAT1 or EAAT2 was injected into Xenopus oocytes without or with additional injection of cRNA encoding wild-type SPAK or wild-type OSR1, constitutively active (T233E)SPAK, WNK insensitive (T233A)SPAK, catalytically inactive (D212A)SPAK, constitutively active (T185E)OSR1, WNK insensitive (T185A)OSR1 or catalytically inactive (D164A)OSR1. The glutamate (2 mM)-induced inward current (I Glu) was taken as a measure of glutamate transport. As a result, I Glu was observed in EAAT1- and in EAAT2-expressing oocytes but not in water-injected oocytes, and was significantly decreased by coexpression of SPAK and OSR1. As shown for EAAT2, SPAK, and OSR1 decreased significantly the maximal transport rate but significantly enhanced the affinity of the carrier. The effect of wild-type SPAK/OSR1 on EAAT1 and EAAT2 was mimicked by (T233E)SPAK and (T185E)OSR1, but not by (T233A)SPAK, (D212A)SPAK, (T185A)OSR1, or (D164A)OSR1. Coexpression of either SPAK or OSR1 decreased the EAAT2 protein abundance in the cell membrane of EAAT2-expressing oocytes. In conclusion, SPAK and OSR1 are powerful negative regulators of the excitatory glutamate transporters EAAT1 and EAAT2.
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Affiliation(s)
- Abeer Abousaab
- Department of Physiology, University of Tübingen, Gmelinstr. 5, 72076, Tübingen, Germany
| | - Jamshed Warsi
- Department of Physiology, University of Tübingen, Gmelinstr. 5, 72076, Tübingen, Germany
| | - Bernat Elvira
- Department of Physiology, University of Tübingen, Gmelinstr. 5, 72076, Tübingen, Germany
| | - Ioana Alesutan
- Department of Physiology, University of Tübingen, Gmelinstr. 5, 72076, Tübingen, Germany
| | - Zohreh Hoseinzadeh
- Department of Physiology, University of Tübingen, Gmelinstr. 5, 72076, Tübingen, Germany
| | - Florian Lang
- Department of Physiology, University of Tübingen, Gmelinstr. 5, 72076, Tübingen, Germany.
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Borrás J, Salker MS, Elvira B, Warsi J, Fezai M, Hoseinzadeh Z, Lang F. SPAK and OSR1 Sensitivity of Excitatory Amino Acid Transporter EAAT3. Nephron Clin Pract 2015; 130:221-8. [PMID: 26112741 DOI: 10.1159/000433567] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2015] [Accepted: 05/20/2015] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND/AIMS Kinases involved in the regulation of epithelial transport include SPAK (SPS1-related proline/alanine-rich kinase) and OSR1 (oxidative stress-responsive kinase 1). SPAK and OSR1 are both regulated by WNK (with-no-K(Lys)) kinases. The present study explored whether SPAK and/or OSR1 influence the excitatory amino acid transporter EAAT3, which accomplishes glutamate and aspartate transport in kidney, intestine and brain. METHODS cRNA encoding EAAT3 was injected into Xenopus laevis oocytes with or without additional injection of cRNA encoding wild-type SPAK, constitutively active (T233E)SPAK, WNK insensitive (T233A)SPAK, catalytically inactive (D212A)SPAK, wild-type OSR1, constitutively active (T185E)OSR1, WNK insensitive (T185A)OSR1 and catalytically inactive (D164A)OSR1. Glutamate-induced current was taken as measure of electrogenic glutamate transport and was quantified utilizing dual electrode voltage clamp. Furthermore, Ussing chamber was employed to determine glutamate transport in the intestine from gene-targeted mice carrying WNK insensitive SPAK (spak(tg/tg)) and from corresponding wild-type mice (spak(+/+)). RESULTS EAAT3 activity was significantly decreased by wild-type SPAK and (T233E)SPAK, but not by (T233A)SPAK and (D212A)SPAK. SPAK decreased maximal transport rate without affecting significantly affinity of the carrier. Similarly, EAAT3 activity was significantly downregulated by wild-type OSR1 and (T185E)OSR1, but not by (T185A)OSR1 and (D164A)OSR1. Again OSR1 decreased maximal transport rate without affecting significantly affinity of the carrier. Intestinal electrogenic glutamate transport was significantly lower in spak(+/+) than in spak(tg/tg) mice. CONCLUSION Both, SPAK and OSR1 are negative regulators of EAAT3 activity.
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Affiliation(s)
- José Borrás
- Department of Physiology I, University of Tübingen, Tubingen, Germany
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85
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Borschewski A, Himmerkus N, Boldt C, Blankenstein KI, McCormick JA, Lazelle R, Willnow TE, Jankowski V, Plain A, Bleich M, Ellison DH, Bachmann S, Mutig K. Calcineurin and Sorting-Related Receptor with A-Type Repeats Interact to Regulate the Renal Na⁺-K⁺-2Cl⁻ Cotransporter. J Am Soc Nephrol 2015; 27:107-19. [PMID: 25967121 DOI: 10.1681/asn.2014070728] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Accepted: 03/16/2015] [Indexed: 01/08/2023] Open
Abstract
The furosemide-sensitive Na(+)-K(+)-2Cl(-)-cotransporter (NKCC2) is crucial for NaCl reabsorption in kidney thick ascending limb (TAL) and drives the urine concentrating mechanism. NKCC2 activity is modulated by N-terminal phosphorylation and dephosphorylation. Serine-threonine kinases that activate NKCC2 have been identified, but less is known about phosphatases that deactivate NKCC2. Inhibition of calcineurin phosphatase has been shown to stimulate transport in the TAL and the distal convoluted tubule. Here, we identified NKCC2 as a target of the calcineurin Aβ isoform. Short-term cyclosporine administration in mice augmented the abundance of phospho-NKCC2, and treatment of isolated TAL with cyclosporine increased the chloride affinity and transport activity of NKCC2. Because sorting-related receptor with A-type repeats (SORLA) may affect NKCC2 phosphoregulation, we used SORLA-knockout mice to test whether SORLA is involved in calcineurin-dependent modulation of NKCC2. SORLA-deficient mice showed more calcineurin Aβ in the apical region of TAL cells and less NKCC2 phosphorylation and activity compared with littermate controls. In contrast, overexpression of SORLA in cultured cells reduced the abundance of endogenous calcineurin Aβ. Cyclosporine administration rapidly normalized the abundance of phospho-NKCC2 in SORLA-deficient mice, and a functional interaction between calcineurin Aβ and SORLA was further corroborated by binding assays in rat kidney extracts. In summary, we have shown that calcineurin Aβ and SORLA are key components in the phosphoregulation of NKCC2. These results may have clinical implications for immunosuppressive therapy using calcineurin inhibitors.
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Affiliation(s)
- Aljona Borschewski
- Department of Anatomy, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | | | - Christin Boldt
- Department of Anatomy, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | | | - James A McCormick
- Division of Nephrology and Hypertension, Oregon Health & Science University and VA Medical Center, Portland, Oregon
| | - Rebecca Lazelle
- Division of Nephrology and Hypertension, Oregon Health & Science University and VA Medical Center, Portland, Oregon
| | - Thomas E Willnow
- Max Delbrueck Center for Molecular Medicine, Berlin, Germany; and
| | - Vera Jankowski
- Medizinische Klinik IV, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Allein Plain
- Institute of Physiology, Kiel University, Kiel, Germany
| | - Markus Bleich
- Institute of Physiology, Kiel University, Kiel, Germany
| | - David H Ellison
- Division of Nephrology and Hypertension, Oregon Health & Science University and VA Medical Center, Portland, Oregon
| | - Sebastian Bachmann
- Department of Anatomy, Charité-Universitätsmedizin Berlin, Berlin, Germany;
| | - Kerim Mutig
- Department of Anatomy, Charité-Universitätsmedizin Berlin, Berlin, Germany;
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Huang CL, Cheng CJ. A unifying mechanism for WNK kinase regulation of sodium-chloride cotransporter. Pflugers Arch 2015; 467:2235-41. [PMID: 25904388 DOI: 10.1007/s00424-015-1708-2] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2015] [Revised: 04/14/2015] [Accepted: 04/15/2015] [Indexed: 12/21/2022]
Abstract
Mammalian with-no-lysine [K] (WNK) kinases are a family of four serine-threonine protein kinases, WNK1-4. Mutations of WNK1 and WNK4 in humans cause pseudohypoaldosteronism type II (PHA2), an autosomal-dominant disease characterized by hypertension and hyperkalemia. Increased Na(+) reabsorption through Na(+)-Cl(-) cotransporter (NCC) in the distal convoluted tubule plays an important role in the pathogenesis of hypertension in patients with PHA2. However, how WNK1 and WNK4 regulate NCC and how mutations of WNKs cause activation of NCC have been controversial. Here, we review current state of literature supporting a compelling model that WNK1 and WNK4 both contribute to stimulation of NCC. The precise combined effects of WNK1 and WNK4 on NCC remain unclear but likely are positive rather than antagonistic. The recent discovery that WNK kinases may function as an intracellular chloride sensor adds a new dimension to the physiological role of WNK kinases. Intracellular chloride-dependent regulation of WNK's may underlie the mechanism of regulation of NCC by extracellular K(+). Definite answer yet will require future investigation by tubular perfusion in mice with altered WNK kinase expression.
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Affiliation(s)
- Chou-Long Huang
- Department of Internal Medicine, Division of Nephrology, UT Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX, 75390-8856, USA.
| | - Chih-Jen Cheng
- Department of Medicine, Division of Nephrology, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan
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87
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Wade JB, Liu J, Coleman R, Grimm PR, Delpire E, Welling PA. SPAK-mediated NCC regulation in response to low-K+ diet. Am J Physiol Renal Physiol 2015; 308:F923-31. [PMID: 25651563 DOI: 10.1152/ajprenal.00388.2014] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2014] [Accepted: 01/24/2015] [Indexed: 01/09/2023] Open
Abstract
The NaCl cotransporter (NCC) of the renal distal convoluted tubule is stimulated by low-K(+) diet by an unknown mechanism. Since recent work has shown that the STE20/SPS-1-related proline-alanine-rich protein kinase (SPAK) can function to stimulate NCC by phosphorylation of specific N-terminal sites, we investigated whether the NCC response to low-K(+) diet is mediated by SPAK. Using phospho-specific antibodies in Western blot and immunolocalization studies of wild-type and SPAK knockout (SPAK(-/-)) mice fed a low-K(+) or control diet for 4 days, we found that low-K(+) diet strongly increased total NCC expression and phosphorylation of NCC. This was associated with an increase in total SPAK expression in cortical homogenates and an increase in phosphorylation of SPAK at the S383 activation site. The increased pNCC in response to low-K(+) diet was blunted but not completely inhibited in SPAK(-/-) mice. These findings reveal that SPAK is an important mediator of the increased NCC activation by phosphorylation that occurs in the distal convoluted tubule in response to a low-K(+) diet, but other low-potassium-activated kinases are likely to be involved.
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Affiliation(s)
- James B Wade
- Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland; and
| | - Jie Liu
- Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland; and
| | - Richard Coleman
- Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland; and
| | - P Richard Grimm
- Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland; and
| | - Eric Delpire
- Department of Anesthesiology, Vanderbilt University School of Medicine, Nashville, Tennessee
| | - Paul A Welling
- Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland; and
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88
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Abstract
The distal convoluted tubule (DCT) is a short nephron segment, interposed between the macula densa and collecting duct. Even though it is short, it plays a key role in regulating extracellular fluid volume and electrolyte homeostasis. DCT cells are rich in mitochondria, and possess the highest density of Na+/K+-ATPase along the nephron, where it is expressed on the highly amplified basolateral membranes. DCT cells are largely water impermeable, and reabsorb sodium and chloride across the apical membrane via electroneurtral pathways. Prominent among this is the thiazide-sensitive sodium chloride cotransporter, target of widely used diuretic drugs. These cells also play a key role in magnesium reabsorption, which occurs predominantly, via a transient receptor potential channel (TRPM6). Human genetic diseases in which DCT function is perturbed have provided critical insights into the physiological role of the DCT, and how transport is regulated. These include Familial Hyperkalemic Hypertension, the salt-wasting diseases Gitelman syndrome and EAST syndrome, and hereditary hypomagnesemias. The DCT is also established as an important target for the hormones angiotensin II and aldosterone; it also appears to respond to sympathetic-nerve stimulation and changes in plasma potassium. Here, we discuss what is currently known about DCT physiology. Early studies that determined transport rates of ions by the DCT are described, as are the channels and transporters expressed along the DCT with the advent of molecular cloning. Regulation of expression and activity of these channels and transporters is also described; particular emphasis is placed on the contribution of genetic forms of DCT dysregulation to our understanding.
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Affiliation(s)
- James A McCormick
- Division of Nephrology & Hypertension, Oregon Health & Science University, & VA Medical Center, Portland, Oregon, United States
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89
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Vorontsova I, Lam L, Delpire E, Lim J, Donaldson P. Identification of the WNK-SPAK/OSR1 signaling pathway in rodent and human lenses. Invest Ophthalmol Vis Sci 2014; 56:310-21. [PMID: 25515571 DOI: 10.1167/iovs.14-15911] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To identify whether the kinases that regulate the activity of cation chloride cotransporters (CCC) in other tissues are also expressed in rat and human lenses. METHODS The expression of with-no-lysine kinase (WNK 1, 3, 4), oxidative stress response kinase 1 (OSR1), and Ste20-like proline alanine rich kinase (SPAK) were determined at either the transcript or protein levels in the rat and human lenses by reverse-transcriptase PCR and/or Western blotting, respectively. Selected kinases were regionally and subcellularly characterized in rat and human lenses. The transparency, wet weight, and tissue morphology of lenses extracted from SPAK knock-out animals was compared with wild-type lenses. RESULTS WNK 1, 3, 4, SPAK, and OSR1 were identified at the transcript level in rat lenses and WNK1, 4, SPAK, and OSR1 expression confirmed at the protein level in both rat and human lenses. SPAK and OSR1 were found to associate with membranes as peripheral proteins and exhibited distinct subcellular and region-specific expression profiles throughout the lens. No significant difference in the wet weight of SPAK knock-out lenses was detected relative to wild-type lenses. However, SPAK knock-out lenses showed an increased susceptibility to opacification. CONCLUSIONS Our results show that the WNK 1, 3, 4, OSR1, and SPAK signaling system known to play a role in regulating the phosphorylation status, and hence activity of the CCCs in other tissues, is also present in the rat and human lenses. The increased susceptibility of SPAK lenses to opacification suggests that disruption of this signaling pathway may compromise the ability of the lens to control its volume, and its ability to maintain its transparency.
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Affiliation(s)
- Irene Vorontsova
- Department of Optometry and Vision Science, University of Auckland, New Zealand The New Zealand National Eye Centre, University of Auckland, New Zealand
| | - Leo Lam
- Department of Optometry and Vision Science, University of Auckland, New Zealand The New Zealand National Eye Centre, University of Auckland, New Zealand
| | - Eric Delpire
- Department of Anesthesiology, Vanderbilt University School of Medicine, Nashville, Tennessee, United States
| | - Julie Lim
- Department of Optometry and Vision Science, University of Auckland, New Zealand The New Zealand National Eye Centre, University of Auckland, New Zealand
| | - Paul Donaldson
- Department of Optometry and Vision Science, University of Auckland, New Zealand The New Zealand National Eye Centre, University of Auckland, New Zealand School of Medical Sciences, University of Auckland, New Zealand
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90
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Warsi J, Elvira B, Bissinger R, Shumilina E, Hosseinzadeh Z, Lang F. Downregulation of peptide transporters PEPT1 and PEPT2 by oxidative stress responsive kinase OSR1. Kidney Blood Press Res 2014; 39:591-9. [PMID: 25531100 DOI: 10.1159/000368469] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/27/2014] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND/AIMS OSR1 (oxidative-stress-responsive kinase 1) participates in the regulation of renal tubular ion transport, cell volume and blood pressure. Whether OSR1 contributes to the regulation of organic solute transport remained; however, elusive. The present study thus explored the OSR1 sensitivity of the peptide transporters PEPT1 and PEPT2. METHODS cRNA encoding PEPT1 or PEPT2 were injected into Xenopus oocytes without or with additional injection of cRNA encoding wild-type OSR1, WNK1 insensitive inactive (T185A)OSR1, constitutively active (T185E)OSR1, and catalytically inactive (D164A)OSR1. Electrogenic peptide (glycine-glycine) transport was determined by dual electrode voltage clamp, the abundance of hemagglutinin-tagged PEPT2 (PEPT2-HA) by chemiluminescence. RESULTS In Xenopus oocytes injected with cRNA encoding PEPT1 or PEPT2, but not in oocytes injected with water, the dipeptide gly-gly (2 mM) generated an appreciable inward current (I(gly-gly)). Coexpression of OSR1 significantly decreased Igly-gly in both PEPT1 and PEPT2 expressing oocytes. The effect of OSR1 coexpression on Igly-gly in PEPT1 expressing oocytes was mimicked by coexpression of (T185E)OSR1, but not of (D164A)OSR1 or (T185A)OSR1. Kinetic analysis revealed that coexpression of OSR1 decreased maximal Igly-gly. OSR1 further decreased the PEPT2-HA protein abundance in the cell membrane. CONCLUSION OSR1 has the capacity to downregulate the peptide transporters PEPT1 and PEPT2 by decreasing the carrier protein abundance in the cell membrane.
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Affiliation(s)
- Jamshed Warsi
- Department of Physiology I, University of Tübingen, Tübingen, Germany
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91
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Fezai M, Elvira B, Borras J, Ben-Attia M, Hoseinzadeh Z, Lang F. Negative regulation of the creatine transporter SLC6A8 by SPAK and OSR1. Kidney Blood Press Res 2014; 39:546-54. [PMID: 25531585 DOI: 10.1159/000368465] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/06/2014] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND/AIMS Transport regulation involves several kinases including SPAK (SPS1-related proline/alanine-rich kinase) and OSR1 (oxidative stress-responsive kinase 1), which are under control of WNK (with-no-K[Lys]) kinases. The present study explored whether SPAK and/or OSR1 participate in the regulation of the creatine transporter CreaT (SLC6A8), which accomplishes Na+ coupled cellular uptake of creatine in several tissues including kidney, intestine, heart, skeletal muscle and brain. METHODS cRNA encoding SLC6A8 was injected into Xenopus laevis oocytes with or without additional injection of cRNA encoding wild-type SPAK, constitutively active (T233E)SPAK, WNK insensitive (T233A)SPAK, catalytically inactive (D212A)SPAK, wild-type OSR1, constitutively active (T185E)OSR1, WNK insensitive (T185A)OSR1 and catalytically inactive (D164A)OSR1. Transporter activity was determined from creatine (1 mM) induced current utilizing dual electrode voltage clamp. RESULTS Coexpression of wild-type SPAK and of (T233E)SPAK, but not of (T233A)SPAK or of (D212A)SPAK was followed by a significant decrease of creatine induced current in SLC6A8 expressing oocytes. Coexpression of SPAK significantly decreased maximal transport rate. Coexpression of wild-type OSR1, (T185E)OSR1 and (T185A)OSR1 but not of (D164A)OSR1 significantly negatively regulated SLC6A8 activity. OSR1 again decreased significantly maximal transport rate. CONCLUSIONS Both, SPAK and OSR1, are negative regulators of the creatine transporter SLC6A8.
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Affiliation(s)
- Myriam Fezai
- Department of Physiology I, University of Tübingen, Tübingen, Germany
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92
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Cheng CJ, Yoon J, Baum M, Huang CL. STE20/SPS1-related proline/alanine-rich kinase (SPAK) is critical for sodium reabsorption in isolated, perfused thick ascending limb. Am J Physiol Renal Physiol 2014; 308:F437-43. [PMID: 25477470 DOI: 10.1152/ajprenal.00493.2013] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
SPAK [STE20 (sterile 20)/SPS1-related proline/alanine-rich kinase] kinase consists of a full-length (FL-) and an alternatively spliced kidney-specific (KS-) isoform. SPAK regulates the NaCl cotransporter (NCC) in the distal convoluted tubule (DCT). The relative abundance and role of FL- vs. KS-SPAK in regulating Na(+)-K(+)-2Cl(-) cotransporter (NKCC2) in thick ascending limb (TAL) are not completely understood. Here, we report that FL-SPAK mRNA was the most abundant in medullary TAL (mTAL), followed by cortical TAL (cTAL) and DCT. KS-SPAK mRNA abundance was relatively lower than FL-SPAK. The ratios of FL-SPAK to KS-SPAK in mTAL, cTAL, and DCT were 12.3, 12.5, and 10.2, respectively. To examine the role of SPAK in the regulation of sodium transport in TAL, we used in vitro microperfusion of mTAL and cTAL isolated from wild-type (WT) and SPAK knockout mice (SPAK-KO) that lack both FL- and KS-SPAK. The rates of sodium absorption in cTAL and mTAL of SPAK-KO mice were 34.5 and 12.5% of WT tubules, respectively. The mRNA levels of related OSR1 kinase and SPAK protease Dnpep in SPAK-KO tubules were not significantly different from WT tubules. We next examined the role of SPAK in the regulation of sodium reabsorption by vasopressin in TAL. Vasopressin increased sodium reabsorption by ∼80% in both mTAL and cTAL from WT mice. While baseline sodium reabsorption was lower in SPAK-KO tubules, vasopressin increased sodium reabsorption over twofold. In conclusion, the combined net effect of SPAK isoforms on sodium reabsorption in TAL is stimulatory. SPAK is not essential for vasopressin stimulation of sodium reabsorption in TAL.
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Affiliation(s)
- Chih-Jen Cheng
- Department of Medicine, Division of Nephrology, UT Southwestern Medical Center, Dallas, Texas; Department of Medicine, Division of Nephrology, Tri-Service General Hospital, National Defense Medical Center, Taipei 114, Taiwan
| | - Joonho Yoon
- Department of Medicine, Division of Nephrology, UT Southwestern Medical Center, Dallas, Texas
| | - Michel Baum
- Department of Medicine, Division of Nephrology, UT Southwestern Medical Center, Dallas, Texas; Department of Pediatrics, UT Southwestern Medical Center, Dallas, Texas; and
| | - Chou-Long Huang
- Department of Medicine, Division of Nephrology, UT Southwestern Medical Center, Dallas, Texas
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93
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Li C, Feng M, Shi Z, Hao Q, Song X, Wang W, Zhao Y, Jiao S, Zhou Z. Structural and biochemical insights into the activation mechanisms of germinal center kinase OSR1. J Biol Chem 2014; 289:35969-78. [PMID: 25389294 DOI: 10.1074/jbc.m114.592097] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The oxidative stress-responsive 1 (OSR1) kinase belongs to the mammalian STE20-like kinase family. OSR1 is activated by with no lysine [K] (WNKs) kinases, and then it phosphorylates cation-coupled Cl-cotransporters, regulating ion homeostasis and cell volume in mammalian cells. However, the specific mechanisms of OSR1 activation remains poorly defined, largely due to its extremely low basal activity. Here, we dissect in detail the regulatory mechanisms of OSR1 activation from the aspects of autoinhibition, upstream kinase WNK, and the newly identified master regulator mouse protein-25 (MO25). Based on our structural and biochemical studies, we propose a "double lock" model, accounting for the tight autoinhibition of OSR1, an effect that has to be removed by WNK before MO25 further activates OSR1. Particularly, the conserved C-terminal (CCT) domain and αAL helix act together to strongly suppress OSR1 basal activity. WNKs bind to the CCT and trigger its conformational rearrangement to release the kinase domain of OSR1, allowing for MO25 binding and full activation. Finally, the regulatory mechanisms of OSR1 activation were further corroborated by cellular studies of OSR1-regulated cell volume control through WNK-OSR1 signaling pathway. Collectively, these results provide insights into the OSR1 kinase activation to facilitate further functional study.
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Affiliation(s)
- Chuanchuan Li
- From the National Center for Protein Science Shanghai, State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China and
| | - Miao Feng
- From the National Center for Protein Science Shanghai, State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China and
| | - Zhubing Shi
- From the National Center for Protein Science Shanghai, State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China and School of Life Sciences and Technology, Tongji University, Shanghai 200092, China
| | - Qian Hao
- From the National Center for Protein Science Shanghai, State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China and
| | - Xiaomin Song
- From the National Center for Protein Science Shanghai, State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China and
| | - Wenjia Wang
- From the National Center for Protein Science Shanghai, State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China and
| | - Yun Zhao
- From the National Center for Protein Science Shanghai, State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China and
| | - Shi Jiao
- From the National Center for Protein Science Shanghai, State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China and
| | - Zhaocai Zhou
- From the National Center for Protein Science Shanghai, State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China and
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94
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Kikuchi E, Mori T, Zeniya M, Isobe K, Ishigami-Yuasa M, Fujii S, Kagechika H, Ishihara T, Mizushima T, Sasaki S, Sohara E, Rai T, Uchida S. Discovery of Novel SPAK Inhibitors That Block WNK Kinase Signaling to Cation Chloride Transporters. J Am Soc Nephrol 2014; 26:1525-36. [PMID: 25377078 DOI: 10.1681/asn.2014060560] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2014] [Accepted: 09/20/2014] [Indexed: 12/21/2022] Open
Abstract
Upon activation by with-no-lysine kinases, STE20/SPS1-related proline-alanine-rich protein kinase (SPAK) phosphorylates and activates SLC12A transporters such as the Na(+)-Cl(-) cotransporter (NCC) and Na(+)-K(+)-2Cl(-) cotransporter type 1 (NKCC1) and type 2 (NKCC2); these transporters have important roles in regulating BP through NaCl reabsorption and vasoconstriction. SPAK knockout mice are viable and display hypotension with decreased activity (phosphorylation) of NCC and NKCC1 in the kidneys and aorta, respectively. Therefore, agents that inhibit SPAK activity could be a new class of antihypertensive drugs with dual actions (i.e., NaCl diuresis and vasodilation). In this study, we developed a new ELISA-based screening system to find novel SPAK inhibitors and screened >20,000 small-molecule compounds. Furthermore, we used a drug repositioning strategy to identify existing drugs that inhibit SPAK activity. As a result, we discovered one small-molecule compound (Stock 1S-14279) and an antiparasitic agent (Closantel) that inhibited SPAK-regulated phosphorylation and activation of NCC and NKCC1 in vitro and in mice. Notably, these compounds had structural similarity and inhibited SPAK in an ATP-insensitive manner. We propose that the two compounds found in this study may have great potential as novel antihypertensive drugs.
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Affiliation(s)
- Eriko Kikuchi
- Department of Nephrology, Graduate School of Medical and Dental Sciences
| | - Takayasu Mori
- Department of Nephrology, Graduate School of Medical and Dental Sciences
| | - Moko Zeniya
- Department of Nephrology, Graduate School of Medical and Dental Sciences
| | - Kiyoshi Isobe
- Department of Nephrology, Graduate School of Medical and Dental Sciences
| | | | - Shinya Fujii
- Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University, Tokyo, Japan; and
| | - Hiroyuki Kagechika
- Chemical Biology Screening Center, and Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University, Tokyo, Japan; and
| | - Tomoaki Ishihara
- Department of Analytical Chemistry, Faculty of Pharmacy, Keio University, Tokyo, Japan
| | - Tohru Mizushima
- Department of Analytical Chemistry, Faculty of Pharmacy, Keio University, Tokyo, Japan
| | - Sei Sasaki
- Department of Nephrology, Graduate School of Medical and Dental Sciences
| | - Eisei Sohara
- Department of Nephrology, Graduate School of Medical and Dental Sciences
| | - Tatemitsu Rai
- Department of Nephrology, Graduate School of Medical and Dental Sciences
| | - Shinichi Uchida
- Department of Nephrology, Graduate School of Medical and Dental Sciences,
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95
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Castrop H, Schießl IM. Physiology and pathophysiology of the renal Na-K-2Cl cotransporter (NKCC2). Am J Physiol Renal Physiol 2014; 307:F991-F1002. [PMID: 25186299 DOI: 10.1152/ajprenal.00432.2014] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The Na-K-2Cl cotransporter (NKCC2; BSC1) is located in the apical membrane of the epithelial cells of the thick ascending limb of the loop of Henle (TAL). NKCC2 facilitates ∼20–25% of the reuptake of the total filtered NaCl load. NKCC2 is therefore one of the transport proteins with the highest overall reabsorptive capacity in the kidney. Consequently, even subtle changes in NKCC2 transport activity considerably alter the renal reabsorptive capacity for NaCl and eventually lead to perturbations of the salt and water homoeostasis. In addition to facilitating the bulk reabsorption of NaCl in the TAL, NKCC2 transport activity in the macula densa cells of the TAL constitutes the initial step of the tubular-vascular communication within the juxtaglomerular apparatus (JGA); this communications allows the TAL to modulate the preglomerular resistance of the afferent arteriole and the renin secretion from the granular cells of the JGA. This review provides an overview of our current knowledge with respect to the general functions of NKCC2, the modulation of its transport activity by different regulatory mechanisms, and new developments in the pathophysiology of NKCC2-dependent renal NaCl transport.
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Affiliation(s)
- Hayo Castrop
- Institute of Physiology, University of Regensburg, Regensburg, Germany
| | - Ina Maria Schießl
- Institute of Physiology, University of Regensburg, Regensburg, Germany
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96
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Warsi J, Dong L, Elvira B, Salker MS, Shumilina E, Hosseinzadeh Z, Lang F. SPAK dependent regulation of peptide transporters PEPT1 and PEPT2. Kidney Blood Press Res 2014; 39:388-98. [PMID: 25376088 DOI: 10.1159/000368451] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/25/2014] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND/AIMS SPAK (STE20-related proline/alanine-rich kinase) is a powerful regulator of renal tubular ion transport and blood pressure. Moreover, SPAK contributes to the regulation of cell volume. Little is known, however, about a role of SPAK in the regulation or organic solutes. The present study thus addressed the influence of SPAK on the peptide transporters PEPT1 and PEPT2. METHODS To this end, cRNA encoding PEPT1 or PEPT2 were injected into Xenopus laevis oocytes without or with additional injection of cRNA encoding wild-type, SPAK, WNK1 insensitive inactive (T233A)SPAK, constitutively active (T233E)SPAK, and catalytically inactive (D212A)SPAK. Electrogenic peptide (glycine-glycine) transport was determined by dual electrode voltage clamp and PEPT2 protein abundance in the cell membrane by chemiluminescence. Intestinal electrogenic peptide transport was estimated from peptide induced current in Ussing chamber experiments of jejunal segments isolated from gene targeted mice expressing SPAK resistant to WNK-dependent activation (spak(tg/tg)) and respective wild-type mice (spak(+/+)). RESULTS In PEPT1 and in PEPT2 expressing oocytes, but not in oocytes injected with water, the dipeptide gly-gly (2 mM) generated an inward current, which was significantly decreased following coexpression of SPAK. The effect of SPAK on PEPT1 was mimicked by (T233E)SPAK, but not by (D212A)SPAK or (T233A)SPAK. SPAK decreased maximal peptide induced current of PEPT1. Moreover, SPAK decreased carrier protein abundance in the cell membrane of PEPT2 expressing oocytes. In intestinal segments gly-gly generated a current, which was significantly higher in spak(tg/tg) than in spak(+/+) mice. CONCLUSION SPAK is a powerful regulator of peptide transporters PEPT1 and PEPT2.
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Affiliation(s)
- Jamshed Warsi
- Department of Physiology I, University of Tübingen, Gmelinstr. 5, 70276 Tübingen, Germany
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97
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Elvira B, Warsi J, Munoz C, Lang F. SPAK and OSR1 sensitivity of voltage-gated K+ channel Kv1.5. J Membr Biol 2014; 248:59-66. [PMID: 25315612 DOI: 10.1007/s00232-014-9741-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2014] [Accepted: 09/30/2014] [Indexed: 12/11/2022]
Abstract
SPS1-related proline/alanine-rich kinase (SPAK) and oxidative stress-responsive kinase 1 (OSR1) are potent regulators of several transporters and ion channels. The kinases are under regulation of with-no-K(Lys) (WNK) kinases. The present study explored whether SPAK and/or OSR1 modify the expression and/or activity of the voltage-gated K(+) channel Kv1.5, which participates in the regulation of diverse functions including atrial cardiac action potential and tumor cell proliferation. cRNA encoding Kv1.5 was injected into Xenopus oocytes with or without additional injection of cRNA encoding wild-type SPAK, constitutively active (T233E)SPAK, WNK insensitive (T233A)SPAK, catalytically inactive (D212A)SPAK, wild-type OSR1, constitutively active (T185E)OSR1, WNK insensitive (T185A)OSR1, and catalytically inactive (D164A)OSR1. Voltage-gated K(+) channel activity was quantified utilizing dual electrode voltage clamp and Kv1.5 channel protein abundance in the cell membrane utilizing chemiluminescence of Kv1.5 containing an extracellular hemagglutinin epitope (Kv1.5-HA). Kv1.5 activity and Kv1.5-HA protein abundance were significantly decreased by wild-type SPAK and (T233E)SPAK, but not by (T233A)SPAK and (D212A)SPAK. Similarly, Kv1.5 activity and Kv1.5-HA protein abundance were significantly down-regulated by wild-type OSR1 and (T185E)OSR1, but not by (T185A)OSR1 and (D164A)OSR1. Both, SPAK and OSR1 decrease cell membrane Kv1.5 protein abundance and activity.
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Affiliation(s)
- Bernat Elvira
- Department of Physiology, University of Tübingen, Gmelinstr. 5, 72076, Tübingen, Germany
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Warsi J, Hosseinzadeh Z, Elvira B, Bissinger R, Shumilina E, Lang F. Regulation of ClC-2 Activity by SPAK and OSR1. Kidney Blood Press Res 2014; 39:378-87. [DOI: 10.1159/000355816] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/23/2014] [Indexed: 11/19/2022] Open
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Elvira B, Munoz C, Borras J, Chen H, Warsi J, Ajay SS, Shumilina E, Lang F. SPAK and OSR1 dependent down-regulation of murine renal outer medullary K channel ROMK1. Kidney Blood Press Res 2014; 39:353-60. [PMID: 25322850 DOI: 10.1159/000355812] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/17/2014] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND/AIMS The kinases SPAK (SPS1-related proline/alanine-rich kinase) and OSR1 (oxidative stress-responsive kinase 1) participate in the regulation of the NaCl cotransporter NCC and the Na+, K+, 2Cl- cotransporter NKCC2. The kinases are regulated by WNK (with-no-K[Lys]) kinases. Mutations of genes encoding WNK kinases underly Gordon's syndrome, a monogenic disease leading to hypertension and hyperkalemia. WNK kinases further regulate the renal outer medullary K+ channel ROMK1. The present study explored, whether SPAK and/or OSR1 have similarly the potential to modify the activity of ROMK1. METHODS ROMK1 was expressed in Xenopus oocytes with or without additional expression of wild-type SPAK, constitutively active (T233E)SPAK, catalytically inactive (D212A)SPAK, wild-type OSR1, constitutively active (T185E)OSR1 and catalytically inactive (D164A)OSR1. Channel activity was determined utilizing dual electrode voltage clamp and ROMK1 protein abundance in the cell membrane utilizing chemiluminescence of ROMK1 containing an extracellular hemagglutinin epitope (ROMK1-HA). RESULTS ROMK1 activity and ROMK1-HA protein abundance were significantly down-regulated by wild-type SPAK and (T233E)SPAK, but not by (D212A)SPAK. Similarly, ROMK1 activity and ROMK1-HA protein abundance were significantly down-regulated by wild-type OSR1 and (T185E)OSR1, but not by (D164A)OSR1. CONCLUSION ROMK1 protein abundance and activity are down-regulated by SPAK and OSR1.
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Affiliation(s)
- Bernat Elvira
- Department of Physiology I, University of Tübingen, Tübingen, Germany
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Posttranslational regulation of the cation–chloride symporter Na+–K+–2Cl− cotransporter-2 in spontaneously hypertensive rat kidneys. J Hypertens 2014; 32:1778-9. [DOI: 10.1097/hjh.0000000000000303] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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