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Ishizawa K, Wang Q, Li J, Xu N, Nemoto Y, Morimoto C, Fujii W, Tamura Y, Fujigaki Y, Tsukamoto K, Fujita T, Uchida S, Shibata S. Inhibition of Sodium Glucose Cotransporter 2 Attenuates the Dysregulation of Kelch-Like 3 and NaCl Cotransporter in Obese Diabetic Mice. J Am Soc Nephrol 2019; 30:782-794. [PMID: 30914436 DOI: 10.1681/asn.2018070703] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Accepted: 02/08/2019] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND Mechanisms underlying the frequent association between salt-sensitive hypertension and type 2 diabetes remain obscure. We previously found that protein kinase C (PKC) activation phosphorylates Kelch-like 3 (KLHL3), an E3 ubiquitin ligase component, at serine 433. We investigated whether impaired KLHL3 activity results in increased renal salt reabsorption via NaCl cotransporter (NCC). METHODS We used the db/db diabetes mouse model to explore KLHL3's role in renal salt handling in type 2 diabetes and evaluated mechanisms of KLHL3 dysregulation in cultured cells. RESULTS We observed PKC activity in the db/db mouse kidney and phosphorylation of serine 433 in KLHL3 (KLHL3S433-P). This modification prevents binding of with-no-lysine (WNK) kinases; however, total KLHL3 levels were decreased, indicating severely impaired KLHL3 activity. This resulted in WNK accumulation, activating NCC in distal convoluted tubules. Ipragliflozin, a sodium glucose cotransporter 2 (SGLT2) inhibitor, lowered PKC activity in distal convoluted tubule cells and reduced KLHL3S433-P and NCC levels, whereas the thiazolidinedione pioglitazone did not, although the two agents similarly reduced in blood glucose levels. We found that, in human embryonic kidney cells expressing KLHL3 and distal convoluted tubule cells, cellular glucose accumulation increased KLHL3S433-P levels through PKC. Finally, the effect of PKC inhibition in the kidney of db/db mice confirmed PKC's causal role in KLHL3S433-P and NCC induction. CONCLUSIONS Dysregulation of KLHL3 is involved in the pathophysiology of type 2 diabetes. These data offer a rationale for use of thiazide in individuals with diabetes and provide insights into the mechanism for cardiorenal protective effects of SGLT2 inhibitors.
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Affiliation(s)
- Kenichi Ishizawa
- Division of Nephrology, Department of Internal Medicine, Teikyo University School of Medicine, Tokyo, Japan
| | - Qin Wang
- Division of Nephrology, Department of Internal Medicine, Teikyo University School of Medicine, Tokyo, Japan.,Department of Nephrology, Second Affiliated Hospital of Harbin Medical University, Harbin, China; and
| | - Jinping Li
- Division of Nephrology, Department of Internal Medicine, Teikyo University School of Medicine, Tokyo, Japan
| | - Ning Xu
- Division of Nephrology, Department of Internal Medicine, Teikyo University School of Medicine, Tokyo, Japan
| | - Yoshikazu Nemoto
- Division of Nephrology, Department of Internal Medicine, Teikyo University School of Medicine, Tokyo, Japan
| | - Chikayuki Morimoto
- Division of Nephrology, Department of Internal Medicine, Teikyo University School of Medicine, Tokyo, Japan
| | - Wataru Fujii
- Division of Nephrology, Department of Internal Medicine, Teikyo University School of Medicine, Tokyo, Japan
| | - Yoshifuru Tamura
- Division of Nephrology, Department of Internal Medicine, Teikyo University School of Medicine, Tokyo, Japan
| | - Yoshihide Fujigaki
- Division of Nephrology, Department of Internal Medicine, Teikyo University School of Medicine, Tokyo, Japan
| | - Kazuhisa Tsukamoto
- Division of Nephrology, Department of Internal Medicine, Teikyo University School of Medicine, Tokyo, Japan
| | - Toshiro Fujita
- Division of Clinical Epigenetics, Research Center for Advanced Science and Technology, The University of Tokyo, Tokyo, Japan
| | - Shunya Uchida
- Division of Nephrology, Department of Internal Medicine, Teikyo University School of Medicine, Tokyo, Japan
| | - Shigeru Shibata
- Division of Nephrology, Department of Internal Medicine, Teikyo University School of Medicine, Tokyo, Japan; .,Division of Clinical Epigenetics, Research Center for Advanced Science and Technology, The University of Tokyo, Tokyo, Japan
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202
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Penton D, Moser S, Wengi A, Czogalla J, Rosenbaek LL, Rigendinger F, Faresse N, Martins JR, Fenton RA, Loffing-Cueni D, Loffing J. Protein Phosphatase 1 Inhibitor-1 Mediates the cAMP-Dependent Stimulation of the Renal NaCl Cotransporter. J Am Soc Nephrol 2019; 30:737-750. [PMID: 30902838 DOI: 10.1681/asn.2018050540] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Accepted: 02/06/2019] [Indexed: 11/03/2022] Open
Abstract
BACKGROUND A number of cAMP-elevating hormones stimulate phosphorylation (and hence activity) of the NaCl cotransporter (NCC) in the distal convoluted tubule (DCT). Evidence suggests that protein phosphatase 1 (PP1) and other protein phosphatases modulate NCC phosphorylation, but little is known about PP1's role and the mechanism regulating its function in the DCT. METHODS We used ex vivo mouse kidney preparations to test whether a DCT-enriched inhibitor of PP1, protein phosphatase 1 inhibitor-1 (I1), mediates cAMP's effects on NCC, and conducted yeast two-hybrid and coimmunoprecipitation experiments in NCC-expressing MDCK cells to explore protein interactions. RESULTS Treating isolated DCTs with forskolin and IBMX increased NCC phosphorylation via a protein kinase A (PKA)-dependent pathway. Ex vivo incubation of mouse kidney slices with isoproterenol, norepinephrine, and parathyroid hormone similarly increased NCC phosphorylation. The cAMP-induced stimulation of NCC phosphorylation strongly correlated with the phosphorylation of I1 at its PKA consensus phosphorylation site (a threonine residue in position 35). We also found an interaction between NCC and the I1-target PP1. Moreover, PP1 dephosphorylated NCC in vitro, and the PP1 inhibitor calyculin A increased NCC phosphorylation. Studies in kidney slices and isolated perfused kidneys of control and I1-KO mice demonstrated that I1 participates in the cAMP-induced stimulation of NCC. CONCLUSIONS Our data suggest a complete signal transduction pathway by which cAMP increases NCC phosphorylation via a PKA-dependent phosphorylation of I1 and subsequent inhibition of PP1. This pathway might be relevant for the physiologic regulation of renal sodium handling by cAMP-elevating hormones, and may contribute to salt-sensitive hypertension in patients with endocrine disorders or sympathetic hyperactivity.
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Affiliation(s)
- David Penton
- Institute of Anatomy, University of Zurich, Zurich, Switzerland.,Swiss National Centre for Competence in Research "Kidney Control of Homeostasis," Zurich, Switzerland
| | - Sandra Moser
- Institute of Anatomy, University of Zurich, Zurich, Switzerland
| | - Agnieszka Wengi
- Institute of Anatomy, University of Zurich, Zurich, Switzerland
| | - Jan Czogalla
- Institute of Anatomy, University of Zurich, Zurich, Switzerland.,Swiss National Centre for Competence in Research "Kidney Control of Homeostasis," Zurich, Switzerland
| | - Lena Lindtoft Rosenbaek
- Department of Biomedicine, Aarhus University, Aarhus, Denmark; and.,Department of Neuroscience, University of Copenhagen, Copenhagen, Denmark
| | | | - Nourdine Faresse
- Institute of Anatomy, University of Zurich, Zurich, Switzerland.,Swiss National Centre for Competence in Research "Kidney Control of Homeostasis," Zurich, Switzerland
| | - Joana R Martins
- Institute of Anatomy, University of Zurich, Zurich, Switzerland.,Swiss National Centre for Competence in Research "Kidney Control of Homeostasis," Zurich, Switzerland
| | - Robert A Fenton
- Department of Biomedicine, Aarhus University, Aarhus, Denmark; and
| | | | - Johannes Loffing
- Institute of Anatomy, University of Zurich, Zurich, Switzerland; .,Swiss National Centre for Competence in Research "Kidney Control of Homeostasis," Zurich, Switzerland
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203
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Effects of High Salt-Low Potassium Diet on Blood Pressure and Vascular Reactivity in Male Sprague Dawley Rats. J Cardiovasc Pharmacol 2019; 71:340-346. [PMID: 29554004 DOI: 10.1097/fjc.0000000000000578] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Sodium (Na) intake increases vascular reactivity. Whether low potassium (K) intake affects vascular reactivity-associated blood pressure (BP) changes is uncertain. This study aimed to determine whether Na-induced increases in BP and vascular reactivity are altered by low K intake. Male Sprague Dawley rats were assigned to 3 dietary groups for 6 weeks: a standard Na-K diet (control, n = 12), a high Na-normal K diet (HS-NormK, n = 12), and a high Na-low K diet (HS-LowK, n = 12). BP was measured at baseline and after the dietary intervention. Na and K excretions and vascular reactivity were measured after the dietary intervention. The Na/K ratio was significantly higher in the HS-LowK compared with the other groups. Systolic and diastolic BPs increased significantly in the HS-NormK and HS-LowK groups. In mesenteric arteries, the dose-response curves for phenylephrine-induced contractions shifted to the left and the EC50 (mean ± SD) was significantly lower in the HS-NormK (0.51 ± 0.17 μM, P = 0.003) and HS-LowK (0.69 ± 0.14 μM, P = 0.005) groups compared with the control (3.24 ± 0.79 μM). Systolic (r = -0.58 P = 0.002) and diastolic (r = -0.61 P = 0.001) BPs were associated with the EC50 of phenylephrine-induced contraction in mesenteric arteries. High Na intake induces increased alpha-1 receptor responsiveness in mesenteric arteries, which may be responsible for the increase in BP and is not affected by low dietary K intake.
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204
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Tomilin V, Mamenko M, Zaika O, Wingo CS, Pochynyuk O. TRPV4 deletion protects against hypokalemia during systemic K + deficiency. Am J Physiol Renal Physiol 2019; 316:F948-F956. [PMID: 30838874 DOI: 10.1152/ajprenal.00043.2019] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Tight regulation of K+ balance is fundamental for normal physiology. Reduced dietary K+ intake, which is common in Western diets, often leads to hypokalemia and associated cardiovascular- and kidney-related pathologies. The distal nephron, and, specifically, the collecting duct (CD), is the major site of controlled K+ reabsorption via H+-K+-ATPase in the state of dietary K+ deficiency. We (Mamenko MV, Boukelmoune N, Tomilin VN, Zaika OL, Jensen VB, O'Neil RG, Pochynyuk OM. Kidney Int 91: 1398-1409, 2017) have previously demonstrated that the transient receptor potential vanilloid type 4 (TRPV4) Ca2+ channel, abundantly expressed in the CD, contributes to renal K+ handling by promoting flow-induced K+ secretion. Here, we investigated a potential role of TRPV4 in controlling H+-K+-ATPase-dependent K+ reabsorption in the CD. Treatment with a K+-deficient diet (<0.01% K+) for 7 days reduced serum K+ levels in wild-type (WT) mice from 4.3 ± 0.2 to 3.3 ± 0.2 mM but not in TRPV4-/- mice (4.3 ± 0.1 and 4.2 ± 0.3 mM, respectively). Furthermore, we detected a significant reduction in 24-h urinary K+ levels in TRPV4-/- compared with WT mice upon switching to K+-deficient diet. TRPV4-/- animals also had significantly more acidic urine on a low-K+ diet, but not on a regular (0.9% K+) or high-K+ (5% K+) diet, which is consistent with increased H+-K+-ATPase activity. Moreover, we detected a greatly accelerated H+-K+-ATPase-dependent intracellular pH extrusion in freshly isolated CDs from TRPV4-/- compared with WT mice fed a K+-deficient diet. Overall, our results demonstrate a novel kaliuretic role of TRPV4 by inhibiting H+-K+-ATPase-dependent K+ reabsorption in the CD. We propose that TRPV4 inhibition could be a novel strategy to manage certain hypokalemic states in clinical settings.
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Affiliation(s)
- Viktor Tomilin
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center at Houston , Houston, Texas
| | - Mykola Mamenko
- Department of Physiology, Medical College of Georgia, Augusta University , Augusta, Georgia
| | - Oleg Zaika
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center at Houston , Houston, Texas
| | - Charles S Wingo
- Division of Nephrology, Hypertension and Transplantation, Department of Medicine, University of Florida , Gainesville, Florida.,North Florida/South Georgia Veterans Health System, Gainesville, Florida
| | - Oleh Pochynyuk
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center at Houston , Houston, Texas
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205
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Su XT, Ellison DH, Wang WH. Kir4.1/Kir5.1 in the DCT plays a role in the regulation of renal K + excretion. Am J Physiol Renal Physiol 2019; 316:F582-F586. [PMID: 30623727 PMCID: PMC6459306 DOI: 10.1152/ajprenal.00412.2018] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Revised: 12/31/2018] [Accepted: 01/02/2019] [Indexed: 02/03/2023] Open
Abstract
The aim of this mini review is to provide an overview regarding the role of inwardly rectifying potassium channel 4.1 (Kir4.1)/Kir5.1 in regulating renal K+ excretion. Deletion of Kir4.1 in the kidney inhibited thiazide-sensitive NaCl cotransporter (NCC) activity in the distal convoluted tubule (DCT) and slightly suppressed Na-K-2Cl cotransporter (NKCC2) function in the thick ascending limb (TAL). Moreover, increased dietary K+ intake inhibited, whereas decreased dietary K+ intake stimulated, the basolateral potassium channel (a Kir4.1/Kir5.1 heterotetramer) in the DCT. The alteration of basolateral potassium conductance is essential for the effect of dietary K+ intake on NCC because deletion of Kir4.1 in the DCT abolished the effect of dietary K+ intake on NCC. Since potassium intake-mediated regulation of NCC plays a key role in regulating renal K+ excretion and potassium homeostasis, the deletion of Kir4.1 caused severe hypokalemia and metabolic alkalosis under control conditions and even during increased dietary K+ intake. Finally, recent studies have suggested that the angiotensin II type 2 receptor (AT2R) and bradykinin-B2 receptor (BK2R) are involved in mediating the effect of high dietary K+ intake on Kir4.1/Kir5.1 in the DCT.
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Affiliation(s)
- Xiao-Tong Su
- Department of Pharmacology, New York Medical College, Valhalla, New York
| | - David H Ellison
- Division of Nephrology and Hypertension, School of Medicine, Oregon Health and Science University , Portland, Oregon
- Renal Section, Veterans Administration Portland Health Care System , Portland, Oregon
| | - Wen-Hui Wang
- Department of Pharmacology, New York Medical College, Valhalla, New York
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206
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Molecular mechanisms for the regulation of blood pressure by potassium. CURRENT TOPICS IN MEMBRANES 2019; 83:285-313. [PMID: 31196607 DOI: 10.1016/bs.ctm.2019.01.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
It has been well documented that the amount of potassium in the diet is associated with blood pressure levels in the population: the higher the potassium consumption, the lower the blood pressure and the cardiovascular mortality. In the last few years certain mechanisms for potassium regulation of salt reabsorption in the kidney have been elucidated at the molecular level. In this work we discuss the evidence demonstrating the relationship between potassium intake and blood pressure levels in human populations and in animal models, as well as the experimental data that reveal the effects of potassium on transepithelial Na+ reabsorption in different nephron segments. We also discuss the physiological relevance of K+-induced natriuresis, and finally, we focus on the molecular mechanisms by which extracellular potassium modulates the activity of the renal NaCl cotransporter, which is the mechanism that has been best dissected so far.
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207
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Abstract
With-no-lysine (WNK) kinases regulate renal sodium-chloride cotransporter (NCC) to maintain body sodium and potassium homeostasis. Gain-of-function mutations of WNK1 and WNK4 in humans lead to a Mendelian hypertensive and hyperkalemic disease pseudohypoaldosteronism type II (PHAII). X-ray crystal structure and in vitro studies reveal chloride ion (Cl-) binds to a hydrophobic pocket within the kinase domain of WNKs to inhibit its activity. The mechanism is thought to be important for physiological regulation of NCC by extracellular potassium. To test the hypothesis that WNK4 senses the intracellular concentration of Cl- physiologically, we generated knockin mice carrying Cl--insensitive mutant WNK4. These mice displayed hypertension, hyperkalemia, hyperactive NCC, and other features fully recapitulating human and mouse models of PHAII caused by gain-of-function WNK4. Lowering plasma potassium levels by dietary potassium restriction increased NCC activity in wild-type, but not in knockin, mice. NCC activity in knockin mice can be further enhanced by the administration of norepinephrine, a known activator of NCC. Raising plasma potassium by oral gavage of potassium inactivated NCC within 1 hour in wild-type mice, but had no effect in knockin mice. The results provide compelling support for the notion that WNK4 is a bona fide physiological intracellular Cl- sensor and that Cl- regulation of WNK4 underlies the mechanism of regulation of NCC by extracellular potassium.
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208
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The interplay of renal potassium and sodium handling in blood pressure regulation: critical role of the WNK-SPAK-NCC pathway. J Hum Hypertens 2019; 33:508-523. [DOI: 10.1038/s41371-019-0170-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2018] [Revised: 12/18/2018] [Accepted: 01/03/2019] [Indexed: 12/19/2022]
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209
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Calcineurin dephosphorylates Kelch-like 3, reversing phosphorylation by angiotensin II and regulating renal electrolyte handling. Proc Natl Acad Sci U S A 2019; 116:3155-3160. [PMID: 30718414 PMCID: PMC6386661 DOI: 10.1073/pnas.1817281116] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Calcineurin inhibitors (CNIs) are potent immunosuppressants; hypertension and hyperkalemia are common adverse effects. Activation of the renal Na-Cl cotransporter (NCC) is implicated in this toxicity; however, the mechanism is unknown. CNIs’ renal effects mimic the hypertension and hyperkalemia resulting from mutations in WNK kinases or in KLHL3-CUL3 ubiquitin ligase. WNKs activate NCC and are degraded by ubiquitylation upon their binding to KLHL3. The binding of WNKs to KLHL3 is prevented by KLHL3 mutations or by PKC-mediated KLHL3 phosphorylation at serine 433. This work shows that calcineurin dephosphorylates KLHL3S433, promoting WNK4 degradation. Conversely, CNIs inhibit KLHL3S433 dephosphorylation, preventing WNK degradation. These findings implicate calcineurin in the normal regulation of KLHL3’s binding of WNK4 and identify a direct target causing CNI-induced pathology. Calcineurin is a calcium/calmodulin-regulated phosphatase known for its role in activation of T cells following engagement of the T cell receptor. Calcineurin inhibitors (CNIs) are widely used as immunosuppressive agents; common adverse effects of CNIs are hypertension and hyperkalemia. While previous studies have implicated activation of the Na-Cl cotransporter (NCC) in the renal distal convoluted tubule (DCT) in this toxicity, the molecular mechanism of this effect is unknown. The renal effects of CNIs mimic the hypertension and hyperkalemia that result from germ-line mutations in with-no-lysine (WNK) kinases and the Kelch-like 3 (KLHL3)–CUL3 ubiquitin ligase complex. WNK4 is an activator of NCC and is degraded by binding to KLHL3 followed by WNK4’s ubiquitylation and proteasomal degradation. This binding is prevented by phosphorylation of KLHL3 at serine 433 (KLHL3S433-P) via protein kinase C, resulting in increased WNK4 levels and increased NCC activity. Mechanisms mediating KLHL3S433-P dephosphorylation have heretofore been unknown. We now demonstrate that calcineurin expressed in DCT is a potent KLHL3S433-P phosphatase. In mammalian cells, the calcium ionophore ionomycin, a calcineurin activator, reduces KLHL3S433-P levels, and this effect is reversed by the calcineurin inhibitor tacrolimus and by siRNA-mediated knockdown of calcineurin. In vivo, tacrolimus increases levels of KLHL3S433-P, resulting in increased levels of WNK4, phosphorylated SPAK, and NCC. Moreover, tacrolimus attenuates KLHL3-mediated WNK4 ubiquitylation and degradation, while this effect is absent in KLHL3 with S433A substitution. Additionally, increased extracellular K+ induced calcineurin-dependent dephosphorylation of KLHL3S433-P. These findings demonstrate that KLHL3S433-P is a calcineurin substrate and implicate increased KLHL3 phosphorylation in tacrolimus-induced pathologies.
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210
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Duan XP, Gu L, Xiao Y, Gao ZX, Wu P, Zhang YH, Meng XX, Wang JL, Zhang DD, Lin DH, Wang WH, Gu R. Norepinephrine-Induced Stimulation of Kir4.1/Kir5.1 Is Required for the Activation of NaCl Transporter in Distal Convoluted Tubule. Hypertension 2019; 73:112-120. [PMID: 30571558 PMCID: PMC6319266 DOI: 10.1161/hypertensionaha.118.11621] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Accepted: 08/10/2018] [Indexed: 01/10/2023]
Abstract
The stimulation of β-adrenergic receptor increases thiazide-sensitive NaCl cotransporter (NCC), an effect contributing to salt-sensitive hypertension by sympathetic stimulation. We now test whether the stimulation of β-adrenergic receptor-induced activation of NCC is achieved through activating basolateral Kir4.1 in the distal convoluted tubule (DCT). Application of norepinephrine increased the basolateral 40 pS K+ channel (Kir4.1/Kir5.1 heterotetramer) in the DCT. The stimulatory effect of norepinephrine on the K+ channel was mimicked by cAMP analogue but abolished by inhibiting PKA (protein kinase A). Also, the effect of norepinephrine on the K+ channel in the DCT was recapitulated by isoproterenol but not by α-adrenergic agonist and blocked by propranolol, suggesting that norepinephrine effect on the K+ channel was mediated by β-adrenergic receptor. The whole-cell recording shows that norepinephrine and isoproterenol increased DCT K+ currents and shifted the K+ current ( IK) reversal potential to negative range (hyperpolarization). Continuous norepinephrine perfusion (7 days) increased DCT K+ currents, hyperpolarized IK reversal potential, and increased the expression of total NCC/phosphorylated NCC, but it had no significant effect on the expression of NKCC2 (type 2 Na-Cl-K cotransporter) and ENaC-α (epithelial Na channel-α subunit). Renal clearance study demonstrated that norepinephrine perfusion augmented thiazide-induced urinary Na+ excretion only in wild-type but not in kidney-specific Kir4.1 knockout mice, suggesting that Kir4.1 is required for mediating the effect of norepinephrine on NCC. However, norepinephrine perfusion did not affect urinary K+ excretion. We conclude that the stimulation of β-adrenergic receptor activates the basolateral Kir4.1 in the DCT and that the activation of Kir4.1 is required for norepinephrine-induced stimulation of NCC.
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Affiliation(s)
- Xin-Peng Duan
- Department of Physiology, Harbin Medical University, Harbin, China
| | - Li Gu
- Department of Physiology, Harbin Medical University, Harbin, China
| | - Yu Xiao
- Department of Physiology, Harbin Medical University, Harbin, China
| | - Zhong-Xiuzi Gao
- Department of Pharmacology, New York Medical College, Valhalla, NY
| | - Peng Wu
- Department of Pharmacology, New York Medical College, Valhalla, NY
| | - Yun-Hong Zhang
- Department of Physiology, Harbin Medical University, Harbin, China
| | - Xin-Xin Meng
- Department of Physiology, Harbin Medical University, Harbin, China
| | - Jun-Lin Wang
- Department of Physiology, Harbin Medical University, Harbin, China
| | - Dan-dan Zhang
- Department of Physiology, Harbin Medical University, Harbin, China
| | - Dao-Hong Lin
- Department of Pharmacology, New York Medical College, Valhalla, NY
| | - Wen-Hui Wang
- Department of Physiology, Harbin Medical University, Harbin, China
- Department of Pharmacology, New York Medical College, Valhalla, NY
| | - Ruimin Gu
- Department of Physiology, Harbin Medical University, Harbin, China
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211
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Wu P, Gao ZX, Su XT, Wang MX, Wang WH, Lin DH. Kir4.1/Kir5.1 Activity Is Essential for Dietary Sodium Intake-Induced Modulation of Na-Cl Cotransporter. J Am Soc Nephrol 2018; 30:216-227. [PMID: 30559144 DOI: 10.1681/asn.2018080799] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Accepted: 11/13/2018] [Indexed: 01/03/2023] Open
Abstract
BACKGROUND Dietary sodium intake regulates the thiazide-sensitive Na-Cl cotransporter (NCC) in the distal convoluted tubule (DCT). Whether the basolateral, inwardly rectifying potassium channel Kir4.1/Kir5.1 (a heterotetramer of Kir4.1/Kir5.1) in the DCT is essential for mediating the effect of dietary sodium intake on NCC activity is unknown. METHODS We used electrophysiology, renal clearance techniques, and immunoblotting to examine effects of Kir4.1/Kir5.1 in the DCT and NCC in wild-type and kidney-specific Kir4.1 knockout mice. RESULTS Low sodium intake stimulated basolateral Kir4.1/Kir5.1 activity, increased basolateral K+ conductance, and hyperpolarized the membrane. Conversely, high sodium intake inhibited the potassium channel, decreased basolateral K+ currents, and depolarized the membrane. Low sodium intake increased total and phosphorylated NCC expression and augmented hydrochlorothiazide-induced natriuresis; high sodium intake had opposite effects. Thus, elevated NCC activity induced by low sodium intake was associated with upregulation of Kir4.1/Kir5.1 activity in the DCT, whereas inhibition of NCC activity by high sodium intake was associated with diminished Kir4.1/Kir5.1 activity. In contrast, dietary sodium intake did not affect NCC activity in knockout mice. Further, Kir4.1 deletion not only abolished basolateral K+ conductance and depolarized the DCT membrane, but also abrogated the stimulating effects induced by low sodium intake on basolateral K+ conductance and hyperpolarization. Finally, dietary sodium intake did not alter urinary potassium excretion rate in hypokalemic knockout and wild-type mice. CONCLUSIONS Stimulation of Kir4.1/Kir5.1 by low intake of dietary sodium is essential for NCC upregulation, and inhibition of Kir4.1/Kir5.1 induced by high sodium intake is a key step for downregulation of NCC.
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Affiliation(s)
- Peng Wu
- Department of Pharmacology, New York Medical College, Valhalla, New York
| | - Zhong-Xiuzi Gao
- Department of Pharmacology, New York Medical College, Valhalla, New York
| | - Xiao-Tong Su
- Department of Pharmacology, New York Medical College, Valhalla, New York
| | - Ming-Xiao Wang
- Department of Pharmacology, New York Medical College, Valhalla, New York
| | - Wen-Hui Wang
- Department of Pharmacology, New York Medical College, Valhalla, New York
| | - Dao-Hong Lin
- Department of Pharmacology, New York Medical College, Valhalla, New York
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212
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Teulon J, Planelles G, Sepúlveda FV, Andrini O, Lourdel S, Paulais M. Renal Chloride Channels in Relation to Sodium Chloride Transport. Compr Physiol 2018; 9:301-342. [DOI: 10.1002/cphy.c180024] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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213
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Rein JL, Coca SG. "I don't get no respect": the role of chloride in acute kidney injury. Am J Physiol Renal Physiol 2018; 316:F587-F605. [PMID: 30539650 DOI: 10.1152/ajprenal.00130.2018] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Acute kidney injury (AKI) is a major public health problem that complicates 10-40% of hospital admissions. Importantly, AKI is independently associated with increased risk of progression to chronic kidney disease, end-stage renal disease, cardiovascular events, and increased risk of in-hospital and long-term mortality. The chloride content of intravenous fluid has garnered much attention over the last decade, as well as its association with excess use and adverse outcomes, including AKI. Numerous studies show that changes in serum chloride concentration, independent of serum sodium and bicarbonate, are associated with increased risk of AKI, morbidity, and mortality. This comprehensive review details the complex renal physiology regarding the role of chloride in regulating renal blood flow, glomerular filtration rate, tubuloglomerular feedback, and tubular injury, as well as the findings of clinical research related to the chloride content of intravenous fluids, changes in serum chloride concentration, and AKI. Chloride is underappreciated in both physiology and pathophysiology. Although the exact mechanism is debated, avoidance of excessive chloride administration is a reasonable treatment option for all patients and especially in those at risk for AKI. Therefore, high-risk patients and those with "incipient" AKI should receive balanced solutions rather than normal saline to minimize the risk of AKI.
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Affiliation(s)
- Joshua L Rein
- Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai , New York, New York
| | - Steven G Coca
- Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai , New York, New York
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214
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Kamel KS, Schreiber M, Halperin ML. Renal potassium physiology: integration of the renal response to dietary potassium depletion. Kidney Int 2018; 93:41-53. [PMID: 29102372 DOI: 10.1016/j.kint.2017.08.018] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Revised: 07/31/2017] [Accepted: 08/03/2017] [Indexed: 01/30/2023]
Abstract
We summarize the current understanding of the physiology of the renal handling of potassium (K+), and present an integrative view of the renal response to K+ depletion caused by dietary K+ restriction. This renal response involves contributions from different nephron segments, and aims to diminish the rate of excretion of K+ as a result of: decreasing the rate of electrogenic (and increasing the rate of electroneutral) reabsorption of sodium in the aldosterone-sensitive distal nephron (ASDN), decreasing the abundance of renal outer medullary K+ channels in the luminal membrane of principal cells in the ASDN, decreasing the flow rate in the ASDN, and increasing the reabsorption of K+ in the cortical and medullary collecting ducts. The implications of this physiology for the association between K+ depletion and hypertension, and K+ depletion and formation of calcium kidney stones are discussed.
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Affiliation(s)
- Kamel S Kamel
- Renal Division, St. Michael's Hospital, University of Toronto, Toronto, Ontario, Canada; Keenan Research Center, Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, Ontario, Canada.
| | - Martin Schreiber
- Renal Division, St. Michael's Hospital, University of Toronto, Toronto, Ontario, Canada
| | - Mitchell L Halperin
- Renal Division, St. Michael's Hospital, University of Toronto, Toronto, Ontario, Canada; Keenan Research Center, Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, Ontario, Canada
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215
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Saritas T, Puelles VG, Su XT, McCormick JA, Welling PA, Ellison DH. Optical Clearing in the Kidney Reveals Potassium-Mediated Tubule Remodeling. Cell Rep 2018; 25:2668-2675.e3. [PMID: 30517856 PMCID: PMC6339512 DOI: 10.1016/j.celrep.2018.11.021] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Revised: 10/08/2018] [Accepted: 11/01/2018] [Indexed: 02/07/2023] Open
Abstract
Distal nephron remodeling contributes to the pathophysiology of many clinically relevant scenarios, including diuretic resistance and certain Mendelian disorders of blood pressure. However, constitutive genetic disruptions are likely to have substantial developmental effects in this segment, and whether tubule remodeling upon physiological stimuli is a normal homeostatic mechanism is not known. Since the distal nephron acts as a potassium sensor, we assessed proliferation and tubule length in three dimensions upon dietary or inducible genetic manipulation by using optical clearing of adult mouse kidneys, whole-mount immunolabeling, and advanced light microscopy. We show that dietary potassium restriction leads promptly to proliferation of various nephron segments, including the distal convoluted tubule, whereas disruption of the potassium sensor Kir4.1 causes atrophy, despite ambient hypokalemia. These results provide proof that kidney tubules adapt rapidly to diet and indicate the power of clearing approaches to assess cell number and tubule length in healthy and diseased kidney.
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Affiliation(s)
- Turgay Saritas
- Division of Nephrology and Hypertension, Oregon Health & Science University, Portland, OR 97239, USA; Division of Nephrology and Clinical Immunology, University Hospital RWTH Aachen, Aachen 52074, Germany.
| | - Victor G Puelles
- Division of Nephrology and Clinical Immunology, University Hospital RWTH Aachen, Aachen 52074, Germany; III. Department of Medicine, University Medical Center, Hamburg-Eppendorf, Hamburg 20246, Germany; Department of Nephrology, Monash Health, Melbourne, VIC 3168, Australia
| | - Xiao-Tong Su
- Division of Nephrology and Hypertension, Oregon Health & Science University, Portland, OR 97239, USA
| | - James A McCormick
- Division of Nephrology and Hypertension, Oregon Health & Science University, Portland, OR 97239, USA
| | - Paul A Welling
- Department of Physiology, University of Maryland, Baltimore, MD 21201, USA; Fondation LeDucq Transatlantic Networks of Excellence, Paris 75116, France
| | - David H Ellison
- Division of Nephrology and Hypertension, Oregon Health & Science University, Portland, OR 97239, USA; Fondation LeDucq Transatlantic Networks of Excellence, Paris 75116, France; Renal Section, Veterans Affairs Portland Health Care System, Portland, OR 97239, USA
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216
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Thomson MN, Schneider W, Mutig K, Ellison DH, Kettritz R, Bachmann S. Patients with hypokalemia develop WNK bodies in the distal convoluted tubule of the kidney. Am J Physiol Renal Physiol 2018; 316:F292-F300. [PMID: 30484345 DOI: 10.1152/ajprenal.00464.2018] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Hypokalemia contributes to the progression of chronic kidney disease, although a definitive pathophysiological theory to explain this remains to be established. K+ deficiency results in profound alterations in renal epithelial transport. These include an increase in salt reabsorption via the Na+-Cl- cotransporter (NCC) of the distal convoluted tubule (DCT), which minimizes electroneutral K+ loss in downstream nephron segments. In experimental conditions of dietary K+ depletion, punctate structures in the DCT containing crucial NCC-regulating kinases have been discovered in the murine DCT and termed "WNK bodies," referring to their component, with no K (lysine) kinases (WNKs). We hypothesized that in humans, WNK bodies occur in hypokalemia as well. Renal needle biopsies of patients with chronic hypokalemic nephropathy and appropriate controls were examined by histological stains and immunofluorescence. Segment- and organelle-specific marker proteins were used to characterize the intrarenal and subcellular distribution of established WNK body constituents, namely, WNKs and Ste20-related proline-alanine-rich kinase (SPAK). In both patients with hypokalemia, WNKs and SPAK concentrated in non-membrane-bound cytoplasmic regions in the DCT, consistent with prior descriptions of WNK bodies. The putative WNK bodies were located in the perinuclear region close to, but not within, the endoplasmic reticulum. They were closely adjacent to microtubules but not clustered in aggresomes. Notably, we provide the first report of WNK bodies, which are functionally challenging structures associated with K+ deficiency, in human patients.
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Affiliation(s)
- Martin N Thomson
- Department of Anatomy, Charité-Universitätsmedizin Berlin, Berlin , Germany
| | - Wolfgang Schneider
- Department of Pathology, Charité-Universitätsmedizin Berlin, Berlin , Germany
| | - Kerim Mutig
- Department of Anatomy, Charité-Universitätsmedizin Berlin, Berlin , Germany
| | - David H Ellison
- Division of Nephrology and Hypertension, Department of Medicine, Oregon Health & Science University , Portland, Oregon
| | - Ralph Kettritz
- Nephrology and Medical Intensive Care Medicine, Charité-Universitätsmedizin Berlin, Berlin , Germany.,Experimental and Clinical Research Center, Charité-Universitätsmedizin Berlin and Max Delbrück Center for Molecular Medicine , Berlin , Germany
| | - Sebastian Bachmann
- Department of Anatomy, Charité-Universitätsmedizin Berlin, Berlin , Germany
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217
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Yeung SMH, Vogt L, Rotmans JI, Hoorn EJ, de Borst MH. Potassium: poison or panacea in chronic kidney disease? Nephrol Dial Transplant 2018; 34:175-180. [DOI: 10.1093/ndt/gfy329] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Accepted: 09/20/2018] [Indexed: 11/15/2022] Open
Affiliation(s)
- Stanley M H Yeung
- Department of Internal Medicine, Division of Nephrology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Liffert Vogt
- Department of Internal Medicine, Section of Nephrology, Amsterdam University Medical Center, Amsterdam, The Netherlands
| | - Joris I Rotmans
- Department of Internal Medicine (Nephrology), Leiden University Medical Center, Leiden, The Netherlands
| | - Ewout J Hoorn
- Department of Internal Medicine, Division of Nephrology and Transplantation, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Martin H de Borst
- Department of Internal Medicine, Division of Nephrology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
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218
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Cornelius RJ, Si J, Cuevas CA, Nelson JW, Gratreak BDK, Pardi R, Yang CL, Ellison DH. Renal COP9 Signalosome Deficiency Alters CUL3-KLHL3-WNK Signaling Pathway. J Am Soc Nephrol 2018; 29:2627-2640. [PMID: 30301860 PMCID: PMC6218864 DOI: 10.1681/asn.2018030333] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Accepted: 09/07/2018] [Indexed: 11/03/2022] Open
Abstract
BACKGROUND The familial hyperkalemic hypertension (FHHt) cullin 3 (CUL3) mutant does not degrade WNK kinases normally, thereby leading to thiazide-sensitive Na-Cl cotransporter (NCC) activation. CUL3 mutant (CUL3Δ9) does not bind normally to the COP9 signalosome (CSN), a deneddylase involved in regulating cullin-RING ligases. CUL3Δ9 also caused increased degradation of the CUL3-WNK substrate adaptor kelch-like 3 (KLHL3). Here, we sought to determine how defective CSN action contributes to the CUL3Δ9 phenotype. METHODS The Pax8/LC1 mouse system was used to generate mice in which the catalytically active CSN subunit, Jab1, was deleted only along the nephron, after full development (KS-Jab1-/-). RESULTS Western blot analysis demonstrated that Jab1 deletion increased the abundance of neddylated CUL3. Moreover, total CUL3 expression was reduced, suggesting decreased CUL3 stability. KLHL3 was almost completely absent in KS-Jab1-/- mice. Conversely, the protein abundances of WNK1, WNK4, and SPAK kinases were substantially higher. Activation of WNK4, SPAK, and OSR1 was indicated by higher phosphorylated protein levels and translocation of the proteins into puncta, as observed by immunofluorescence. The ratio of phosphorylated NCC to total NCC was also higher. Surprisingly, NCC protein abundance was low, likely contributing to hypokalemia and Na+ and K+ wasting. Additionally, long-term Jab1 deletion resulted in kidney damage. CONCLUSIONS Together, the results indicate that deficient CSN binding contributes importantly to the FHHt phenotype. Although defective CUL3Δ9-faciliated WNK4 degradation likely contributes, dominant effects on KLHL3 may be a second factor that is necessary for the phenotype.
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Affiliation(s)
- Ryan J Cornelius
- Division of Nephrology and Hypertension, Department of Medicine, Oregon Health and Science University, Portland, Oregon
| | - Jinge Si
- Division of Nephrology and Hypertension, Department of Medicine, Oregon Health and Science University, Portland, Oregon
| | - Catherina A Cuevas
- Division of Nephrology and Hypertension, Department of Medicine, Oregon Health and Science University, Portland, Oregon
| | - Jonathan W Nelson
- Division of Nephrology and Hypertension, Department of Medicine, Oregon Health and Science University, Portland, Oregon
| | - Brittany D K Gratreak
- Division of Nephrology and Hypertension, Department of Medicine, Oregon Health and Science University, Portland, Oregon
| | - Ruggero Pardi
- School of Medicine and Scientific Institute, San Raffaele University, Milan, Italy; and
| | - Chao-Ling Yang
- Division of Nephrology and Hypertension, Department of Medicine, Oregon Health and Science University, Portland, Oregon
| | - David H Ellison
- Division of Nephrology and Hypertension, Department of Medicine, Oregon Health and Science University, Portland, Oregon;
- Renal Section, Veterans Affairs Portland Health Care System, Portland, Oregon
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219
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Velentzas PD, Zhang L, Das G, Chang TK, Nelson C, Kobertz WR, Baehrecke EH. The Proton-Coupled Monocarboxylate Transporter Hermes Is Necessary for Autophagy during Cell Death. Dev Cell 2018; 47:281-293.e4. [PMID: 30318245 DOI: 10.1016/j.devcel.2018.09.015] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Revised: 07/25/2018] [Accepted: 09/14/2018] [Indexed: 02/06/2023]
Abstract
Nutrient availability influences the production and degradation of materials that are required for cell growth and survival. Autophagy is a nutrient-regulated process that is used to degrade cytoplasmic materials and has been associated with human diseases. Solute transporters influence nutrient availability and sensing, yet we know little about how transporters influence autophagy. Here, we screen for solute transporters that are required for autophagy-dependent cell death and identify CG11665/hermes. We show that hermes is required for both autophagy during steroid-triggered salivary gland cell death and TNF-induced non-apoptotic eye cell death. hermes encodes a proton-coupled monocarboxylate transporter that preferentially transports pyruvate over lactate. mTOR signaling is elevated in hermes mutant cells, and decreased mTOR function suppresses the hermes salivary gland cell death phenotype. Hermes is most similar to human SLC16A11, a protein that was recently implicated in type 2 diabetes, thus providing a link between pyruvate, mTOR, autophagy, and possibly metabolic disorders.
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Affiliation(s)
- Panagiotis D Velentzas
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Lejie Zhang
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Gautam Das
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Tsun-Kai Chang
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Medical School, Worcester, MA 01605, USA; Cancer Immunology, Genentech Inc, South San Francisco, CA 94080, USA
| | - Charles Nelson
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Medical School, Worcester, MA 01605, USA; Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - William R Kobertz
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Eric H Baehrecke
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Medical School, Worcester, MA 01605, USA.
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220
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Wang MX, Su XT, Wu P, Gao ZX, Wang WH, Staub O, Lin DH. Kir5.1 regulates Nedd4-2-mediated ubiquitination of Kir4.1 in distal nephron. Am J Physiol Renal Physiol 2018; 315:F986-F996. [PMID: 29897283 PMCID: PMC6230743 DOI: 10.1152/ajprenal.00059.2018] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Revised: 05/11/2018] [Accepted: 05/29/2018] [Indexed: 11/22/2022] Open
Abstract
Kir4.1/5.1 heterotetramer participates in generating the negative cell membrane potential in distal convoluted tubule (DCT) and plays a critical role in determining the activity of Na-Cl cotransporter (NCC). Kir5.1 contains a phosphothreonine motif at its COOH terminus (AA249-252). Coimmunoprecipitation showed that Nedd4-2 was associated with Kir5.1 in HEK293 cells cotransfected with Kir5.1 or Kir4.1/Kir5.1. GST pull-down further confirmed the association between Nedd4-2 and Kir5.1. Ubiquitination assay showed that Nedd4-2 increased the ubiquitination of Kir4.1/Kir5.1 heterotetramer in the cells cotransfected with Kir4.1/Kir5.1, but it has no effect on Kir4.1 or Kir5.1 alone. Patch-clamp and Western blot also demonstrated that coexpression of Nedd4-2 but not Nedd4-1 decreased K currents and Kir4.1 expression in the cells cotransfected with Kir4.1 and Kir5.1. In contrast, Nedd4-2 fails to inhibit Kir4.1 in the absence of Kir5.1 or in the cells transfected with the inactivated form of Nedd4-2 (Nedd4-2C821A). Moreover, the mutation of TPVT motif in the COOH terminus of Kir5.1 largely abolished the association of Nedd4-2 with Kir5.1 and abolished the inhibitory effect of Nedd4-2 on K currents in HEK293 cells transfected with Kir4.1 and Kir5.1 mutant (Kir5.1T249A). Finally, the basolateral K conductance in the DCT and Kir4.1 expression is significantly increased in the kidney-specific Nedd4-2 knockout or in Kir5.1 knockout mice in comparison to their corresponding wild-type littermates. We conclude that Nedd4-2 binds to Kir5.1 at the phosphothreonine motif of the COOH terminus, and the association of Nedd4-2 with Kir5.1 facilitates the ubiquitination of Kir4.1, thereby regulating its plasma expression in the DCT.
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Affiliation(s)
- Ming-Xiao Wang
- Department of Physiology, Zunyi Medical College, Zunyi, China
- Department of Pharmacology, New York Medical College, Valhalla, New York
| | - Xiao-Tong Su
- Department of Pharmacology, New York Medical College, Valhalla, New York
| | - Peng Wu
- Department of Pharmacology, New York Medical College, Valhalla, New York
| | - Zhong-Xiuzi Gao
- Department of Pharmacology, New York Medical College, Valhalla, New York
| | - Wen-Hui Wang
- Department of Pharmacology, New York Medical College, Valhalla, New York
| | - Olivier Staub
- Department of Pharmacology and Toxicology, University of Lausanne , Lausanne , Switzerland
| | - Dao-Hong Lin
- Department of Pharmacology, New York Medical College, Valhalla, New York
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221
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Wardak H, Tutakhel OAZ, Van Der Wijst J. Role of the alternative splice variant of NCC in blood pressure control. Channels (Austin) 2018; 12:346-355. [PMID: 30264650 PMCID: PMC6207291 DOI: 10.1080/19336950.2018.1528820] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The renal thiazide-sensitive sodium-chloride cotransporter (NCC), located in the distal convoluted tubule (DCT) of the kidney, plays an important role in blood pressure regulation by fine-tuning sodium excretion. The human SLC12A3 gene, encoding NCC, gives rise to three isoforms, of which only the third isoform (NCC3) has been extensively investigated so far. However, recent studies unraveled the importance of the isoforms 1 and 2, collectively referred to as NCC splice variant (NCCSV), in several (patho)physiological conditions. In the human kidney, NCCSV localizes to the apical membrane of the DCT and could constitute a functional route for renal sodium-chloride reabsorption. Analysis of urinary extracellular vesicles (uEVs), a non-invasive method for measuring renal responses, demonstrated that NCCSV abundance changes in response to acute water loading and correlates with patients’ thiazide responsiveness. Furthermore, a novel phosphorylation site at serine 811 (S811), exclusively present in NCCSV, was shown to play an instrumental role in NCCSV as well as NCC3 function. This review aims to summarize these new insights of NCCSV function in humans that broadens the understanding on NCC regulation in blood pressure control.
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Affiliation(s)
- Hila Wardak
- a Department of Physiology , Radboud Institute for Molecular Life Sciences, Radboud university medical center , Nijmegen , The Netherland
| | - Omar A Z Tutakhel
- a Department of Physiology , Radboud Institute for Molecular Life Sciences, Radboud university medical center , Nijmegen , The Netherland.,b Department of Translational Metabolic Laboratory , Radboud university medical center , Nijmegen , The Netherlands
| | - Jenny Van Der Wijst
- a Department of Physiology , Radboud Institute for Molecular Life Sciences, Radboud university medical center , Nijmegen , The Netherland
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222
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Chitturi C, Novak JE. Diuretics in the Management of Cardiorenal Syndrome. Adv Chronic Kidney Dis 2018; 25:425-433. [PMID: 30309460 DOI: 10.1053/j.ackd.2018.08.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Revised: 08/13/2018] [Accepted: 08/14/2018] [Indexed: 12/21/2022]
Abstract
The leading cause of death worldwide is cardiovascular disease. The heart and the kidneys are functionally interdependent, such that dysfunction in one organ may cause dysfunction in the other. By one estimate, more than 60% of patients with congestive heart failure develop chronic kidney disease. Volume overload and congestion are hallmarks of heart failure, and these findings are associated with severe symptoms and poor outcomes. Given the importance of congestion, diuretics remain a cornerstone of heart failure management. However, diuretic treatment remains largely empirical, with little evidence currently available to guide decisions. In this review, we discuss the pathophysiology of cardiorenal syndrome, the pharmacology of loop diuretics, mechanisms of diuretic resistance, and evidence-based treatment paradigms.
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223
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Palygin O, Pochynyuk O, Staruschenko A. Distal tubule basolateral potassium channels: cellular and molecular mechanisms of regulation. Curr Opin Nephrol Hypertens 2018; 27:373-378. [PMID: 29894319 PMCID: PMC6217967 DOI: 10.1097/mnh.0000000000000437] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
PURPOSE OF REVIEW Multiple clinical and translational evidence support benefits of high potassium diet; however, there many uncertainties underlying the molecular and cellular mechanisms determining effects of dietary potassium. Kir4.1 and Kir5.1 proteins form a functional heteromer (Kir4.1/Kir5.1), which is the primary inwardly rectifying potassium channel on the basolateral membrane of both distal convoluted tubule (DCT) and the collecting duct principal cells. The purpose of this mini-review is to summarize latest advances in our understanding of the evolution, physiological relevance and mechanisms controlling these channels. RECENT FINDINGS Kir4.1 and Kir5.1 channels play a critical role in determining electrolyte homeostasis in the kidney and blood pressure, respectively. It was reported that Kir4.1/Kir5.1 serves as potassium sensors in the distal nephron responding to variations in dietary intake and hormonal stimuli. Global and kidney specific knockouts of either channel resulted in hypokalemia and severe cardiorenal phenotypes. Furthermore, knock out of Kir5.1 in Dahl salt-sensitive rat background revealed the crucial role of the Kir4.1/Kir5.1 channel in salt-induced hypertension. SUMMARY Here, we focus on reviewing novel experimental evidence of the physiological function, expression and hormonal regulation of renal basolateral inwardly rectifying potassium channels. Further investigation of molecular and cellular mechanisms controlling Kir4.1 and Kir4.1/Kir5.1-mediating pathways and development of specific compounds targeting these channels function is essential for proper control of electrolyte homeostasis and blood pressure.
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Affiliation(s)
- Oleg Palygin
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI 53226
| | - Oleh Pochynyuk
- Department of Integrative Biology, University of Texas Health Science Center, Houston, TX 77030
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224
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Malik S, Lambert E, Zhang J, Wang T, Clark HL, Cypress M, Goldman BI, Porter GA, Pena S, Nino W, Gray DA. Potassium conservation is impaired in mice with reduced renal expression of Kir4.1. Am J Physiol Renal Physiol 2018; 315:F1271-F1282. [PMID: 30110571 DOI: 10.1152/ajprenal.00022.2018] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
To better understand the role of the inward-rectifying K channel Kir4.1 (KCNJ10) in the distal nephron, we initially studied a global Kir4.1 knockout mouse (gKO), which demonstrated the hypokalemia and hypomagnesemia seen in SeSAME/EAST syndrome and was associated with reduced Na/Cl cotransporter (NCC) expression. Lethality by ~3 wk, however, limits the usefulness of this model, so we developed a kidney-specific Kir4.1 "knockdown" mouse (ksKD) using a cadherin 16 promoter and Cre-loxP methodology. These mice appeared normal and survived to adulthood. Kir4.1 protein expression was decreased ~50% vs. wild-type (WT) mice by immunoblotting, and immunofluorescence showed moderately reduced Kir4.1 staining in distal convoluted tubule that was minimal or absent in connecting tubule and cortical collecting duct. Under control conditions, the ksKD mice showed metabolic alkalosis and relative hypercalcemia but were normokalemic and mildly hypermagnesemic despite decreased NCC expression. In addition, the mice had a severe urinary concentrating defect associated with hypernatremia, enlarged kidneys with tubulocystic dilations, and reduced aquaporin-3 expression. On a K/Mg-free diet for 1 wk, however, ksKD mice showed marked hypokalemia (serum K: 1.5 ± 0.1 vs. 3.0 ± 0.1 mEq/l for WT), which was associated with renal K wasting (transtubular K gradient: 11.4 ± 0.8 vs. 1.6 ± 0.4 in WT). Phosphorylated-NCC expression increased in WT but not ksKD mice on the K/Mg-free diet, suggesting that loss of NCC adaptation underlies the hypokalemia. In conclusion, even modest reduction in Kir4.1 expression results in impaired K conservation, which appears to be mediated by reduced expression of activated NCC.
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Affiliation(s)
- Sundeep Malik
- Department of Pharmacology and Physiology, School of Medicine, University of Rochester , Rochester, New York
| | - Emily Lambert
- Nephrology Division, Department of Medicine, University of Rochester , Rochester, New York
| | - Junhui Zhang
- Department of Cellular and Molecular Physiology, Yale University School of Medicine , New Haven, Connecticut
| | - Tong Wang
- Department of Cellular and Molecular Physiology, Yale University School of Medicine , New Haven, Connecticut
| | - Heather L Clark
- Nephrology Division, Department of Medicine, University of Rochester , Rochester, New York
| | - Michael Cypress
- Nephrology Division, Department of Medicine, University of Rochester , Rochester, New York
| | - Bruce I Goldman
- Pathology and Laboratory Medicine, University of Rochester , Rochester, New York
| | - George A Porter
- Cardiology Division, Department of Pediatrics, University of Rochester , Rochester, New York
| | - Salvador Pena
- Nephrology Division, Department of Medicine, University of Rochester , Rochester, New York
| | - Wilson Nino
- Nephrology Division, Department of Medicine, University of Rochester , Rochester, New York
| | - Daniel A Gray
- Nephrology Division, Department of Medicine, University of Rochester , Rochester, New York
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225
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Ostrosky-Frid M, Castañeda-Bueno M, Gamba G. Regulation of the renal NaCl cotransporter by the WNK/SPAK pathway: lessons learned from genetically altered animals. Am J Physiol Renal Physiol 2018; 316:F146-F158. [PMID: 30089030 DOI: 10.1152/ajprenal.00288.2018] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The renal thiazide-sensitive NaCl cotransporter (NCC) is the major salt transport pathway in the distal convoluted tubule of the mammalian nephron. NCC activity is critical for modulation of arterial blood pressure and serum potassium levels. Reduced activity of NCC in genetic diseases results in arterial hypotension and hypokalemia, while increased activity results in genetic diseases featuring hypertension and hyperkalemia. Several hormones and physiological conditions modulate NCC activity through a final intracellular complex pathway involving kinases and ubiquitin ligases. A substantial amount of work has been conducted to understand this pathway in the last 15 yr, but advances over the last 3 yr have helped to begin to understand how these regulatory proteins interact with each other and modulate the activity of this important cotransporter. In this review, we present the current model of NCC regulation by the Cullin 3 protein/Kelch-like 3 protein/with no lysine kinase/STE20-serine-proline alanine-rich kinase (CUL3/KELCH3-WNK-SPAK) pathway. We present a review of all genetically altered mice that have been used to translate most of the proposals made from in vitro experiments into in vivo observations that have helped to elucidate the model at the physiological level. Many questions have been resolved, but some others will require further models to be constructed. In addition, unexpected observations in mice have raised new questions and identified regulatory pathways that were previously unknown.
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Affiliation(s)
- Mauricio Ostrosky-Frid
- Molecular Physiology Unit, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México , Mexico City, Mexico.,PECEM, Facultad de Medicina, Universidad Nacional Autónoma de México , Mexico City, Mexico
| | - María Castañeda-Bueno
- Department of Nephrology and Mineral Metabolism, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán , Mexico City, Mexico
| | - Gerardo Gamba
- Molecular Physiology Unit, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México , Mexico City, Mexico.,Department of Nephrology and Mineral Metabolism, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán , Mexico City, Mexico.,Tecnológico de Monterrey, Escuela de Medicina y Ciencias de la Salud, Monterrey, Mexico
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226
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Zhang DD, Gao ZX, Vio CP, Xiao Y, Wu P, Zhang H, Guo XW, Meng XX, Gu L, Wang JL, Duan XP, Lin DH, Wang WH, Gu R. Bradykinin Stimulates Renal Na + and K + Excretion by Inhibiting the K + Channel (Kir4.1) in the Distal Convoluted Tubule. Hypertension 2018; 72:361-369. [PMID: 29915013 PMCID: PMC6043363 DOI: 10.1161/hypertensionaha.118.11070] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Revised: 03/11/2018] [Accepted: 05/10/2018] [Indexed: 12/31/2022]
Abstract
Stimulation of BK2R (bradykinin [BK] B2 receptor) has been shown to increase renal Na+ excretion. The aim of the present study is to explore the role of BK2R in regulating Kir4.1 and NCC (NaCl cotransporter) in the distal convoluted tubule (DCT). Immunohistochemical studies demonstrated that BK2R was highly expressed in both apical and lateral membrane of Kir4.1-positive tubules, such as DCT. Patch-clamp experiments demonstrated that BK inhibited the basolateral 40-pS K+ channel (a Kir4.1/5.1 heterotetramer) in the DCT, and this effect was blocked by BK2R antagonist but not by BK1R (BK B1 receptor) antagonist. Whole-cell recordings also demonstrated that BK decreased the basolateral K+ conductance of the DCT and depolarized the membrane. Renal clearance experiments showed that BK increased urinary Na+ and K+ excretion. However, the BK-induced natriuretic effect was completely abolished in KS-Kir4.1 KO (kidney-specific conditional Kir4.1 knockout) mice, suggesting that Kir4.1 activity is required for BK-induced natriuresis. The continuous infusion of BK with osmotic pump for 3 days decreased the basolateral K+ conductance and the negativity of the DCT membrane. Western blot showed that infusion of BK decreased the expression of total NCC and phosphorylated NCC. Renal clearance experiments demonstrated that thiazide-induced natriuresis was blunted in the mice receiving BK infusion, suggesting that BK inhibited NCC function. Consequently, mice receiving BK infusion for 3 days were hypokalemic. We conclude that stimulation of BK2R inhibits NCC activity, increases urinary K+ excretion, and causes mice hypokalemia and that Kir4.1 is required for BK2R-mediated stimulation of urinary Na+ and K+ excretion.
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Affiliation(s)
- Dan-Dan Zhang
- Department of Physiology, Harbin Medical University, Harbin, China
| | - Zhong-Xiuzi Gao
- Department of Pharmacology, New York Medical College, Valhalla, NY
| | - Carlos P Vio
- Center for Ageing and Regeneration Care-UC, Department of Physiology, Pontificia Universidad Catolica de Chile, Santiago, Chile
| | - Yu Xiao
- Department of Physiology, Harbin Medical University, Harbin, China
| | - Peng Wu
- Department of Pharmacology, New York Medical College, Valhalla, NY
| | - Hao Zhang
- Department of Physiology, Harbin Medical University, Harbin, China
| | - Xi-Wen Guo
- Department of Physiology, Harbin Medical University, Harbin, China
| | - Xin-Xin Meng
- Department of Physiology, Harbin Medical University, Harbin, China
| | - Li Gu
- Department of Physiology, Harbin Medical University, Harbin, China
| | - Jun-Lin Wang
- Department of Physiology, Harbin Medical University, Harbin, China
| | - Xin-Peng Duan
- Department of Physiology, Harbin Medical University, Harbin, China
| | - Dao-Hong Lin
- Department of Pharmacology, New York Medical College, Valhalla, NY
| | - Wen-Hui Wang
- Department of Pharmacology, New York Medical College, Valhalla, NY
| | - Ruimin Gu
- Department of Physiology, Harbin Medical University, Harbin, China
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227
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Yamauchi T, Doi S, Nakashima A, Doi T, Sohara E, Uchida S, Masaki T. Na +-Cl - cotransporter-mediated chloride uptake contributes to hypertension and renal damage in aldosterone-infused rats. Am J Physiol Renal Physiol 2018; 315:F300-F312. [PMID: 29631358 DOI: 10.1152/ajprenal.00504.2016] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Recently, in addition to epithelial sodium channel alpha-subunit (αENaC), the thiazide-sensitive sodium-chloride cotransporter (NCC) and pendrin, also known as sodium-independent chloride/iodide transporter, were reported to be activated by aldosterone. Here, we investigated whether chloride (Cl-) is responsible for hypertension, inflammation, and renal damage in aldosterone-infused rats. Following left nephrectomy, 8-wk-old male Sprague-Dawley rats were allocated into four groups: 1) drinking 1.0% sodium chloride solution with aldosterone infusion (Aldo/NaCl rats); 2) drinking 1.44% sodium bicarbonate solution with aldosterone infusion (Aldo/NaHCO3 rats); 3) drinking distilled water with aldosterone infusion (Aldo/water rats); and 4) drinking distilled water without aldosterone infusion (sham rats). Additionally, heminephrectomized rats with aldosterone infusion were fed a 0.26% NaCl diet (control); 8.0% NaCl diet (high-Na/high-Cl); or a 4.0% NaCl 6.67% sodium citrate diet (high-Na/half-Cl). Last, Aldo/NaCl rats were treated with or without hydrochlorothiazide. Blood pressure in the Aldo/NaCl rats was significantly higher than in the Aldo/NaHCO3 rats, which was associated with the increased expression of NCC. Expression of markers of inflammation (CD3, CD68, interleukin-17A) and fibrosis (α-smooth muscle actin, collagen 1) were also increased in Aldo/NaCl rats. Similarly, aldosterone-infused rats fed a high-Na/half-Cl diet had lower blood pressure than those fed a high-Na/high-Cl diet, with a reduction of phosphorylated NCC, but not αENaC and pendrin. NCC inhibition with hydrochlorothiazide attenuated interleukin-17A protein expression along with the phosphorylation of NCC in Aldo/NaCl rats. These findings suggest that NCC-mediated Cl- uptake plays important roles in the development of aldosterone-induced hypertension and renal injury.
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Affiliation(s)
- Takahiro Yamauchi
- Department of Nephrology, Hiroshima University Hospital , Hiroshima , Japan
| | - Shigehiro Doi
- Department of Nephrology, Hiroshima University Hospital , Hiroshima , Japan
| | - Ayumu Nakashima
- Department of Nephrology, Hiroshima University Hospital , Hiroshima , Japan
| | - Toshiki Doi
- Department of Nephrology, Hiroshima University Hospital , Hiroshima , Japan
| | - Eisei Sohara
- Department of Nephrology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University , Tokyo , Japan
| | - Shinichi Uchida
- Department of Nephrology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University , Tokyo , Japan
| | - Takao Masaki
- Department of Nephrology, Hiroshima University Hospital , Hiroshima , Japan
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228
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López-Cayuqueo KI, Chavez-Canales M, Pillot A, Houillier P, Jayat M, Baraka-Vidot J, Trepiccione F, Baudrie V, Büsst C, Soukaseum C, Kumai Y, Jeunemaître X, Hadchouel J, Eladari D, Chambrey R. A mouse model of pseudohypoaldosteronism type II reveals a novel mechanism of renal tubular acidosis. Kidney Int 2018; 94:514-523. [PMID: 30146013 DOI: 10.1016/j.kint.2018.05.001] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Revised: 04/26/2018] [Accepted: 05/03/2018] [Indexed: 02/04/2023]
Abstract
Pseudohypoaldosteronism type II (PHAII) is a genetic disease characterized by association of hyperkalemia, hyperchloremic metabolic acidosis, hypertension, low renin, and high sensitivity to thiazide diuretics. It is caused by mutations in the WNK1, WNK4, KLHL3 or CUL3 gene. There is strong evidence that excessive sodium chloride reabsorption by the sodium chloride cotransporter NCC in the distal convoluted tubule is involved. WNK4 is expressed not only in distal convoluted tubule cells but also in β-intercalated cells of the cortical collecting duct. These latter cells exchange intracellular bicarbonate for external chloride through pendrin, and therefore, account for renal base excretion. However, these cells can also mediate thiazide-sensitive sodium chloride absorption when the pendrin-dependent apical chloride influx is coupled to apical sodium influx by the sodium-driven chloride/bicarbonate exchanger. Here we determine whether this system is involved in the pathogenesis of PHAII. Renal pendrin activity was markedly increased in a mouse model carrying a WNK4 missense mutation (Q562E) previously identified in patients with PHAII. The upregulation of pendrin led to an increase in thiazide-sensitive sodium chloride absorption by the cortical collecting duct, and it caused metabolic acidosis. The function of apical potassium channels was altered in this model, and hyperkalemia was fully corrected by pendrin genetic ablation. Thus, we demonstrate an important contribution of pendrin in renal regulation of sodium chloride, potassium and acid-base homeostasis and in the pathophysiology of PHAII. Furthermore, we identify renal distal bicarbonate secretion as a novel mechanism of renal tubular acidosis.
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Affiliation(s)
- Karen I López-Cayuqueo
- Institut National de la Santé et de la Recherche Médicale, Unité Mixte de Recherche 970, Paris, France; Centro de Estudios Científicos, Valdivia, Chile
| | - Maria Chavez-Canales
- Institut National de la Santé et de la Recherche Médicale, Unité Mixte de Recherche 970, Paris, France
| | - Alexia Pillot
- Centre National de la Recherche Scientifique Equipe de Recherche Labelisée 8228, Institut National de la Santé et de la Recherche Médicale, Unité Mixte de Recherche_S1138, Centre de Recherche des Cordeliers, Paris, France
| | - Pascal Houillier
- Centre National de la Recherche Scientifique Equipe de Recherche Labelisée 8228, Institut National de la Santé et de la Recherche Médicale, Unité Mixte de Recherche_S1138, Centre de Recherche des Cordeliers, Paris, France; Genetics, Assistance Publique-Hôpitaux de Paris, Hôpital Européen Georges Pompidou, Paris, France
| | - Maximilien Jayat
- Institut National de la Santé et de la Recherche Médicale, Unité Mixte de Recherche 970, Paris, France
| | - Jennifer Baraka-Vidot
- Institut National de la Santé et de la Recherche Médicale, Unité Mixte de Recherche 1188, CYROI, Sainte Clotilde, La Réunion, France
| | - Francesco Trepiccione
- Institut National de la Santé et de la Recherche Médicale, Unité Mixte de Recherche 970, Paris, France
| | - Véronique Baudrie
- Institut National de la Santé et de la Recherche Médicale, Unité Mixte de Recherche 970, Paris, France; Genetics, Assistance Publique-Hôpitaux de Paris, Hôpital Européen Georges Pompidou, Paris, France
| | - Cara Büsst
- Institut National de la Santé et de la Recherche Médicale, Unité Mixte de Recherche 970, Paris, France
| | - Christelle Soukaseum
- Institut National de la Santé et de la Recherche Médicale, Unité Mixte de Recherche 970, Paris, France
| | - Yusuke Kumai
- Institut National de la Santé et de la Recherche Médicale, Unité Mixte de Recherche 970, Paris, France
| | - Xavier Jeunemaître
- Institut National de la Santé et de la Recherche Médicale, Unité Mixte de Recherche 970, Paris, France; Genetics, Assistance Publique-Hôpitaux de Paris, Hôpital Européen Georges Pompidou, Paris, France
| | - Juliette Hadchouel
- Institut National de la Santé et de la Recherche Médicale, Unité Mixte de Recherche 970, Paris, France
| | - Dominique Eladari
- Institut National de la Santé et de la Recherche Médicale, Unité Mixte de Recherche 970, Paris, France; Service d'Explorations Fonctionnelles Rénales, Hôpital Felix Guyon, CHU de la Réunion, Saint Denis, La Réunion, France; Institut National de la Santé et de la Recherche Médicale, Unité Mixte de Recherche 1188, CYROI, Sainte Clotilde, La Réunion, France.
| | - Régine Chambrey
- Institut National de la Santé et de la Recherche Médicale, Unité Mixte de Recherche 970, Paris, France; Institut National de la Santé et de la Recherche Médicale, Unité Mixte de Recherche 1188, CYROI, Sainte Clotilde, La Réunion, France; Centre National de la Recherche Scientifique, Délégation Paris Michel-Ange, Paris, France.
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229
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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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230
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Murillo-de-Ozores AR, Rodríguez-Gama A, Bazúa-Valenti S, Leyva-Ríos K, Vázquez N, Pacheco-Álvarez D, De La Rosa-Velázquez IA, Wengi A, Stone KL, Zhang J, Loffing J, Lifton RP, Yang CL, Ellison DH, Gamba G, Castañeda-Bueno M. C-terminally truncated, kidney-specific variants of the WNK4 kinase lack several sites that regulate its activity. J Biol Chem 2018; 293:12209-12221. [PMID: 29921588 DOI: 10.1074/jbc.ra118.003037] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Revised: 06/14/2018] [Indexed: 12/13/2022] Open
Abstract
WNK lysine-deficient protein kinase 4 (WNK4) is an important regulator of renal salt handling. Mutations in its gene cause pseudohypoaldosteronism type II, mainly arising from overactivation of the renal Na+/Cl- cotransporter (NCC). In addition to full-length WNK4, we have observed faster migrating bands (between 95 and 130 kDa) in Western blots of kidney lysates. Therefore, we hypothesized that these could correspond to uncharacterized WNK4 variants. Here, using several WNK4 antibodies and WNK4-/- mice as controls, we showed that these bands indeed correspond to short WNK4 variants that are not observed in other tissue lysates. LC-MS/MS confirmed these bands as WNK4 variants that lack C-terminal segments. In HEK293 cells, truncation of WNK4's C terminus at several positions increased its kinase activity toward Ste20-related proline/alanine-rich kinase (SPAK), unless the truncated segment included the SPAK-binding site. Of note, this gain-of-function effect was due to the loss of a protein phosphatase 1 (PP1)-binding site in WNK4. Cotransfection with PP1 resulted in WNK4 dephosphorylation, an activity that was abrogated in the PP1-binding site WNK4 mutant. The electrophoretic mobility of the in vivo short variants of renal WNK4 suggested that they lack the SPAK-binding site and thus may not behave as constitutively active kinases toward SPAK. Finally, we show that at least one of the WNK4 short variants may be produced by proteolysis involving a Zn2+-dependent metalloprotease, as recombinant full-length WNK4 was cleaved when incubated with kidney lysate.
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Affiliation(s)
| | - Alejandro Rodríguez-Gama
- Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Mexico City 14080, Mexico
| | - Silvana Bazúa-Valenti
- Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Mexico City 14080, Mexico
| | - Karla Leyva-Ríos
- Escuela de Medicina, Universidad Panamericana, Mexico City 03920, Mexico
| | - Norma Vázquez
- Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Mexico City 14080, Mexico
| | | | - Inti A De La Rosa-Velázquez
- Genomics Laboratory, RAI, Universidad Nacional Autónoma de México-Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City 14080, Mexico
| | - Agnieszka Wengi
- Institute of Anatomy and Swiss National Centre of Competence in Research "Kidney Control of Homeostasis," University of Zurich, Zurich 8057, Switzerland
| | - Kathryn L Stone
- MS and Proteomics Resource, W. M. Keck Biotechnology Resource Laboratory, Yale University School of Medicine, New Haven 06510, Connecticut
| | - Junhui Zhang
- Department of Genetics, Yale University School of Medicine, New Haven 06510, Connecticut
| | - Johannes Loffing
- Institute of Anatomy and Swiss National Centre of Competence in Research "Kidney Control of Homeostasis," University of Zurich, Zurich 8057, Switzerland
| | - Richard P Lifton
- Department of Genetics, Yale University School of Medicine, New Haven 06510, Connecticut; Laboratory of Human Genetics and Genomics, Rockefeller University, New York, New York 10065
| | - Chao-Ling Yang
- Division of Nephrology and Hypertension, Department of Medicine, Oregon Health and Science University, Portland, Oregon 97239; Veterans Affairs Portland Health Care System, Portland, Oregon 97239
| | - David H Ellison
- Division of Nephrology and Hypertension, Department of Medicine, Oregon Health and Science University, Portland, Oregon 97239; Veterans Affairs Portland Health Care System, Portland, Oregon 97239
| | - Gerardo Gamba
- Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Mexico City 14080, Mexico; Department of Nephrology and Mineral Metabolism, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City 14080, Mexico; Tecnológico de Monterrey, Escuela de Medicina y Ciencias de la Salud, Monterrey 64710, Nuevo León, Mexico
| | - Maria Castañeda-Bueno
- Department of Nephrology and Mineral Metabolism, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City 14080, Mexico.
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231
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232
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Argaiz ER, Chavez-Canales M, Ostrosky-Frid M, Rodríguez-Gama A, Vázquez N, Gonzalez-Rodriguez X, Garcia-Valdes J, Hadchouel J, Ellison D, Gamba G. Kidney-specific WNK1 isoform (KS-WNK1) is a potent activator of WNK4 and NCC. Am J Physiol Renal Physiol 2018; 315:F734-F745. [PMID: 29846116 DOI: 10.1152/ajprenal.00145.2018] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Familial hyperkalemic hypertension (FHHt) can be mainly attributed to increased activity of the renal Na+:Cl- cotransporter (NCC), which is caused by altered expression and regulation of the with-no-lysine (K) 1 (WNK1) or WNK4 kinases. The WNK1 gene gives rise to a kidney-specific isoform that lacks the kinase domain (KS-WNK1), the expression of which occurs primarily in the distal convoluted tubule. The role played by KS-WNK1 in the modulation of the WNK/STE20-proline-alanine rich kinase (SPAK)/NCC pathway remains elusive. In the present study, we assessed the effect of human KS-WNK1 on NCC activity and on the WNK4-SPAK pathway. Microinjection of oocytes with human KS-WNK1 cRNA induces remarkable activation and phosphorylation of SPAK and NCC. The effect of KS-WNK1 was abrogated by eliminating a WNK-WNK-interacting domain and by a specific WNK inhibitor, WNK463, indicating that the activation of SPAK/NCC by KS-WNK1 is due to interaction with another WNK kinase. Under control conditions in oocytes, the activating serine 335 of the WNK4 T loop is not phosphorylated. In contrast, this serine becomes phosphorylated when the intracellular chloride concentration ([Cl-]i) is reduced or when KS-WNK1 is coexpressed with WNK4. KS-WNK1-mediated activation of WNK4 is not due to a decrease of the [Cl-]i. Coimmunoprecipitation analysis revealed that KS-WNK1 and WNK4 interact with each other and that WNK4 becomes autophosphorylated at serine 335 when it is associated with KS-WNK1. Together, these observations suggest that WNK4 becomes active in the presence of KS-WNK1, despite a constant [Cl-]i.
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Affiliation(s)
- Eduardo R Argaiz
- 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.,Tecnológico de Monterrey, Escuela de Medicina y Ciencias de la Salud, Monterrey, Nuevo León , Mexico
| | - Maria Chavez-Canales
- INSERM UMRS1155, University Pierre and Marie Curie, Faculty of Medicine , Paris , France.,Translational Medicine Unit, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México and Instituto Nacional de Cardiología Ignacio Chávez, Tlalpan, México City, Mexico
| | - Mauricio Ostrosky-Frid
- Department of Nephrology and Mineral Metabolism, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Tlalpan Mexico City, Mexico.,PECEM, Facultad de Medicina, Universidad Nacional Autónoma de México, Coyoacan, Mexico City, Mexico
| | - Alejandro Rodríguez-Gama
- Molecular Physiology Unit, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Tlalpan, Mexico City, Mexico
| | - Norma Vázquez
- 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
| | - Xochiquetzal Gonzalez-Rodriguez
- Departamento de Química Analítica, Facultad de Química, Universidad Nacional Autónoma de México, Coyoacan, Mexico City, Mexico
| | - Jesus Garcia-Valdes
- Departamento de Química Analítica, Facultad de Química, Universidad Nacional Autónoma de México, Coyoacan, Mexico City, Mexico
| | - Juliette Hadchouel
- INSERM UMRS1155, University Pierre and Marie Curie, Faculty of Medicine , Paris , France
| | - David Ellison
- Division of Nephrology and Hypertension, Department of Medicine, Oregon Health and Science University , Portland, Oregon.,Veterans Affairs Portland Health Care System, Portland, Oregon
| | - 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.,Tecnológico de Monterrey, Escuela de Medicina y Ciencias de la Salud, Monterrey, Nuevo León , Mexico
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233
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Yang YS, Xie J, Yang SS, Lin SH, Huang CL. Differential roles of WNK4 in regulation of NCC in vivo. Am J Physiol Renal Physiol 2018; 314:F999-F1007. [PMID: 29384416 PMCID: PMC6031911 DOI: 10.1152/ajprenal.00177.2017] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Revised: 01/08/2018] [Accepted: 01/17/2018] [Indexed: 11/22/2022] Open
Abstract
The Na+-Cl- cotransporter (NCC) in distal convoluted tubule (DCT) plays important roles in renal NaCl reabsorption. The current hypothesis for the mechanism of regulation of NCC focuses on WNK4 and intracellular Cl- concentration ([Cl-]i). WNK kinases bind Cl-, and Cl- binding decreases the catalytic activity. It is believed that hypokalemia under low K+ intake decreases [Cl-]i to activate WNK4, which thereby phosphorylates and stimulates NCC through activation of SPAK. However, increased NCC activity and apical NaCl entry would mitigate the fall in [Cl-]i. Whether [Cl-]i in DCT under low-K+ diet is sufficiently low to activate WNK4 is unknown. Furthermore, increased luminal NaCl delivery also stimulates NCC and causes upregulation of the transporter. Unlike low K+ intake, increased luminal NaCl delivery would tend to increase [Cl-]i. Thus we investigated the role of WNK4 and [Cl-]i in regulating NCC. We generated Wnk4-knockout mice and examined regulation of NCC by low K+ intake and by increased luminal NaCl delivery in knockout (KO) and wild-type mice. Wnk4-KO mice have marked reduction in the abundance, phosphorylation, and functional activity of NCC vs. wild type. Low K+ intake increases NCC phosphorylation and functional activity in wild-type mice, but not in Wnk4-KO mice. Increased luminal NaCl delivery similarly upregulates NCC, which, contrary to low K+ intake, is not abolished in Wnk4-KO mice. The results reveal that modulation of WNK4 activity by [Cl-]i is not the sole mechanism for regulating NCC. Increased luminal NaCl delivery upregulates NCC via yet unknown mechanism(s) that may override inhibition of WNK4 by high [Cl-]i.
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MESH Headings
- Animals
- Biological Transport
- Gene Expression Regulation, Enzymologic
- Injections, Subcutaneous
- Kidney Tubules, Distal/drug effects
- Kidney Tubules, Distal/enzymology
- Mice, Inbred C57BL
- Mice, Knockout
- Phosphorylation
- Potassium, Dietary/metabolism
- Protein Serine-Threonine Kinases/deficiency
- Protein Serine-Threonine Kinases/genetics
- Protein Serine-Threonine Kinases/metabolism
- Renal Elimination
- Renal Reabsorption
- Sodium Chloride/administration & dosage
- Sodium Chloride/metabolism
- Sodium Chloride Symporter Inhibitors/pharmacology
- Solute Carrier Family 12, Member 3/deficiency
- Solute Carrier Family 12, Member 3/genetics
- Solute Carrier Family 12, Member 3/metabolism
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Affiliation(s)
- Yih-Sheng Yang
- Division of Nephrology, Department of Medicine, University of Texas Southwestern Medical Center , Dallas, Texas
| | - Jian Xie
- Division of Nephrology, Department of Medicine, University of Texas Southwestern Medical Center , Dallas, Texas
| | - Sung-Sen Yang
- Division of Nephrology, Department of Medicine, Tri-Service General Hospital, and Graduate Institute of Medical Sciences, National Defense Medical Center , Taipei , Taiwan
- Graduate Institute of Biomedical Sciences, Academia Sinica, Taipei , Taiwan
| | - Shih-Hua Lin
- Division of Nephrology, Department of Medicine, Tri-Service General Hospital, and Graduate Institute of Medical Sciences, National Defense Medical Center , Taipei , Taiwan
| | - Chou-Long Huang
- Division of Nephrology, Department of Medicine, University of Texas Southwestern Medical Center , Dallas, Texas
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234
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Affiliation(s)
- Paul A Welling
- Department of Physiology, Maryland Center for Kidney Discovery, University of Maryland Medical School, Baltimore, Maryland
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235
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Wang MX, Cuevas CA, Su XT, Wu P, Gao ZX, Lin DH, McCormick JA, Yang CL, Wang WH, Ellison DH. Potassium intake modulates the thiazide-sensitive sodium-chloride cotransporter (NCC) activity via the Kir4.1 potassium channel. Kidney Int 2018; 93:893-902. [PMID: 29310825 PMCID: PMC6481177 DOI: 10.1016/j.kint.2017.10.023] [Citation(s) in RCA: 105] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Revised: 10/04/2017] [Accepted: 10/12/2017] [Indexed: 12/14/2022]
Abstract
Kir4.1 in the distal convoluted tubule plays a key role in sensing plasma potassium and in modulating the thiazide-sensitive sodium-chloride cotransporter (NCC). Here we tested whether dietary potassium intake modulates Kir4.1 and whether this is essential for mediating the effect of potassium diet on NCC. High potassium intake inhibited the basolateral 40 pS potassium channel (a Kir4.1/5.1 heterotetramer) in the distal convoluted tubule, decreased basolateral potassium conductance, and depolarized the distal convoluted tubule membrane in Kcnj10flox/flox mice, herein referred to as control mice. In contrast, low potassium intake activated Kir4.1, increased potassium currents, and hyperpolarized the distal convoluted tubule membrane. These effects of dietary potassium intake on the basolateral potassium conductance and membrane potential in the distal convoluted tubule were completely absent in inducible kidney-specific Kir4.1 knockout mice. Furthermore, high potassium intake decreased, whereas low potassium intake increased the abundance of NCC expression only in the control but not in kidney-specific Kir4.1 knockout mice. Renal clearance studies demonstrated that low potassium augmented, while high potassium diminished, hydrochlorothiazide-induced natriuresis in control mice. Disruption of Kir4.1 significantly increased basal urinary sodium excretion but it abolished the natriuretic effect of hydrochlorothiazide. Finally, hypokalemia and metabolic alkalosis in kidney-specific Kir4.1 knockout mice were exacerbated by potassium restriction and only partially corrected by a high-potassium diet. Thus, Kir4.1 plays an essential role in mediating the effect of dietary potassium intake on NCC activity and potassium homeostasis.
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MESH Headings
- Alkalosis/genetics
- Alkalosis/metabolism
- Alkalosis/physiopathology
- Animals
- Disease Models, Animal
- Female
- Homeostasis
- Hydrochlorothiazide/pharmacology
- Hypokalemia/genetics
- Hypokalemia/metabolism
- Hypokalemia/physiopathology
- Kidney Tubules, Distal/drug effects
- Kidney Tubules, Distal/metabolism
- Kidney Tubules, Distal/physiopathology
- Male
- Membrane Potentials
- Mice, Knockout
- Natriuresis
- Potassium Channels, Inwardly Rectifying/deficiency
- Potassium Channels, Inwardly Rectifying/genetics
- Potassium Channels, Inwardly Rectifying/metabolism
- Potassium, Dietary/metabolism
- Renal Elimination
- Sodium/urine
- Sodium Chloride Symporter Inhibitors/pharmacology
- Solute Carrier Family 12, Member 3/genetics
- Solute Carrier Family 12, Member 3/metabolism
- Kir5.1 Channel
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Affiliation(s)
- Ming-Xiao Wang
- Department of Physiology, Zunyi Medical College, Zunyi, China; Department of Pharmacology, New York Medical College, Valhalla, New York, USA
| | - Catherina A Cuevas
- Department of Medicine, Oregon Health & Science University, Portland, Oregon, USA
| | - Xiao-Tong Su
- Department of Pharmacology, New York Medical College, Valhalla, New York, USA
| | - Peng Wu
- Department of Pharmacology, New York Medical College, Valhalla, New York, USA
| | - Zhong-Xiuzi Gao
- Department of Pharmacology, New York Medical College, Valhalla, New York, USA
| | - Dao-Hong Lin
- Department of Pharmacology, New York Medical College, Valhalla, New York, USA
| | - James A McCormick
- Department of Medicine, Oregon Health & Science University, Portland, Oregon, USA
| | - Chao-Ling Yang
- Department of Pharmacology, New York Medical College, Valhalla, New York, USA
| | - Wen-Hui Wang
- Department of Pharmacology, New York Medical College, Valhalla, New York, USA.
| | - David H Ellison
- Department of Medicine, Oregon Health & Science University, Portland, Oregon, USA.
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236
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Wu P, Gao ZX, Duan XP, Su XT, Wang MX, Lin DH, Gu R, Wang WH. AT2R (Angiotensin II Type 2 Receptor)-Mediated Regulation of NCC (Na-Cl Cotransporter) and Renal K Excretion Depends on the K Channel, Kir4.1. Hypertension 2018; 71:622-630. [PMID: 29483225 PMCID: PMC5843543 DOI: 10.1161/hypertensionaha.117.10471] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Revised: 10/26/2017] [Accepted: 12/21/2017] [Indexed: 02/02/2023]
Abstract
AT2R (AngII [angiotensin II] type 2 receptor) is expressed in the distal nephrons. The aim of the present study is to examine whether AT2R regulates NCC (Na-Cl cotransporter) and Kir4.1 of the distal convoluted tubule. AngII inhibited the basolateral 40 pS K channel (a Kir4.1/5.1 heterotetramer) in the distal convoluted tubule treated with losartan but not with PD123319. AT2R agonist also inhibits the K channel, indicating that AT2R was involved in tonic regulation of Kir4.1. The infusion of PD123319 stimulated the expression of tNCC (total NCC) and pNCC (phosphorylated NCC; Thr53) by a time-dependent way with the peak at 4 days. PD123319 treatment (4 days) stimulated the basolateral 40 pS K channel activity, augmented the basolateral K conductance, and increased the negativity of distal convoluted tubule membrane. The stimulation of Kir4.1 was essential for PD123319-induced increase in NCC because inhibiting AT2R increased the expression of tNCC and pNCC only in wild-type but not in the kidney-specific Kir4.1 knockout mice. Renal clearance study showed that thiazide-induced natriuretic effect was larger in PD123319-treated mice for 4 days than untreated mice. However, this effect was absent in kidney-specific Kir4.1 knockout mice which were also Na wasting under basal conditions. Finally, application of AT2R antagonist decreased the renal ability of K excretion and caused hyperkalemia in wild-type but not in kidney-specific Kir4.1 knockout mice. We conclude that AT2R-dependent regulation of NCC requires Kir4.1 in the distal convoluted tubule and that AT2R plays a role in stimulating K excretion by inhibiting Kir4.1 and NCC.
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Affiliation(s)
- Peng Wu
- From the Department of Pharmacology, New York Medical College, Valhalla (P.W., Z.-X.G., X.-T.S., M.-X.W., D.-H.L., W.-H.W.); and Department of Physiology, Harbin Medical University, China (X.-P.D., R.G.)
| | - Zhong-Xiuzi Gao
- From the Department of Pharmacology, New York Medical College, Valhalla (P.W., Z.-X.G., X.-T.S., M.-X.W., D.-H.L., W.-H.W.); and Department of Physiology, Harbin Medical University, China (X.-P.D., R.G.)
| | - Xin-Peng Duan
- From the Department of Pharmacology, New York Medical College, Valhalla (P.W., Z.-X.G., X.-T.S., M.-X.W., D.-H.L., W.-H.W.); and Department of Physiology, Harbin Medical University, China (X.-P.D., R.G.)
| | - Xiao-Tong Su
- From the Department of Pharmacology, New York Medical College, Valhalla (P.W., Z.-X.G., X.-T.S., M.-X.W., D.-H.L., W.-H.W.); and Department of Physiology, Harbin Medical University, China (X.-P.D., R.G.)
| | - Ming-Xiao Wang
- From the Department of Pharmacology, New York Medical College, Valhalla (P.W., Z.-X.G., X.-T.S., M.-X.W., D.-H.L., W.-H.W.); and Department of Physiology, Harbin Medical University, China (X.-P.D., R.G.)
| | - Dao-Hong Lin
- From the Department of Pharmacology, New York Medical College, Valhalla (P.W., Z.-X.G., X.-T.S., M.-X.W., D.-H.L., W.-H.W.); and Department of Physiology, Harbin Medical University, China (X.-P.D., R.G.)
| | - Ruimin Gu
- From the Department of Pharmacology, New York Medical College, Valhalla (P.W., Z.-X.G., X.-T.S., M.-X.W., D.-H.L., W.-H.W.); and Department of Physiology, Harbin Medical University, China (X.-P.D., R.G.)
| | - Wen-Hui Wang
- From the Department of Pharmacology, New York Medical College, Valhalla (P.W., Z.-X.G., X.-T.S., M.-X.W., D.-H.L., W.-H.W.); and Department of Physiology, Harbin Medical University, China (X.-P.D., R.G.).
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237
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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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238
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Palmer BF, Clegg DJ. Renal Considerations in the Treatment of Hypertension. Am J Hypertens 2018; 31:394-401. [PMID: 29373638 DOI: 10.1093/ajh/hpy013] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
There are renal implications when employing intensive blood pressure control strategies. While this approach provides cardiovascular benefit in patients with and without chronic kidney disease, the impact on renal disease progression differs according to the pattern of underlying renal injury. In the setting of proteinuria, stringent blood pressure control has generally conferred a protective effect on renal disease progression, but in the absence of proteinuria, this benefit tends to be much less impressive. Thiazide diuretics are frequently part of the regimen to achieve intensive blood pressure control. These drugs can cause hyponatremia and present with biochemical evidence mimicking the syndrome of inappropriate antidiuretic hormone secretion. Altered prostaglandin transport may explain the unique susceptibility to this complication observed in some patients. Hyperkalemia is also a complication of intensive blood pressure lowering particularly in the setting of renin-angiotensin-aldosterone blockade. There are strategies and new drugs now available that can allow use of these blockers and at the same time ensure a normal plasma potassium concentration.
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Affiliation(s)
- Biff F Palmer
- Department of Medicine, Division of Nephrology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Deborah J Clegg
- Biomedical Research Department, Diabetes and Obesity Research Division, Cedars-Sinai Medical Center, Los Angeles, California
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239
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Deletion of claudin-10 rescues claudin-16–deficient mice from hypomagnesemia and hypercalciuria. Kidney Int 2018; 93:580-588. [DOI: 10.1016/j.kint.2017.08.029] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Revised: 08/13/2017] [Accepted: 08/24/2017] [Indexed: 11/24/2022]
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240
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Anti-inflammatory, anti-rheumatic and analgesic activities of 2-(5-mercapto-1,3,4-oxadiazol-2-yl)-N-propylbenzenesulphonamide (MOPBS) in rodents. Inflammopharmacology 2018; 26:1037-1049. [DOI: 10.1007/s10787-018-0446-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Accepted: 01/29/2018] [Indexed: 01/08/2023]
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241
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Rafael C, Soukaseum C, Baudrie V, Frère P, Hadchouel J. Consequences of SPAK inactivation on Hyperkalemic Hypertension caused by WNK1 mutations: evidence for differential roles of WNK1 and WNK4. Sci Rep 2018; 8:3249. [PMID: 29459793 PMCID: PMC5818654 DOI: 10.1038/s41598-018-21405-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2017] [Accepted: 01/10/2018] [Indexed: 12/16/2022] Open
Abstract
Mutations of the gene encoding WNK1 [With No lysine (K) kinase 1] or WNK4 cause Familial Hyperkalemic Hypertension (FHHt). Previous studies have shown that the activation of SPAK (Ste20-related Proline/Alanine-rich Kinase) plays a dominant role in the development of FHHt caused by WNK4 mutations. The implication of SPAK in FHHt caused by WNK1 mutation has never been investigated. To clarify this issue, we crossed WNK1+/FHHt mice with SPAK knock-in mice in which the T-loop Thr243 residue was mutated to alanine to prevent activation by WNK kinases. We show that WNK1+/FHHT:SPAK243A/243A mice display an intermediate phenotype, between that of control and SPAK243A/243A mice, with normal blood pressure but hypochloremic metabolic alkalosis. NCC abundance and phosphorylation levels also decrease below the wild-type level in the double-mutant mice but remain higher than in SPAK243A/243A mice. This is different from what was observed in WNK4-FHHt mice in which SPAK inactivation completely restored the phenotype and NCC expression to wild-type levels. Although these results confirm that FHHt caused by WNK1 mutations is dependent on the activation of SPAK, they suggest that WNK1 and WNK4 play different roles in the distal nephron.
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Affiliation(s)
- Chloé Rafael
- Institut National de la Santé et de la Recherche Médicale (INSERM), Unit 970, Paris Cardiovascular Research Center, Paris, France.,Universités Paris-Descartes et Paris-Diderot, Sorbonne Paris Cité, Paris, France.,Sorbonne Université, Paris, France.,INSERM UMR_S1155, Tenon Hospital, Paris, France
| | - Christelle Soukaseum
- Institut National de la Santé et de la Recherche Médicale (INSERM), Unit 970, Paris Cardiovascular Research Center, Paris, France.,Universités Paris-Descartes et Paris-Diderot, Sorbonne Paris Cité, Paris, France.,INSERM UMR_S1176, CHU de Bicêtre, Le Kremlin-Bicêtre, France
| | - Véronique Baudrie
- Institut National de la Santé et de la Recherche Médicale (INSERM), Unit 970, Paris Cardiovascular Research Center, Paris, France.,Universités Paris-Descartes et Paris-Diderot, Sorbonne Paris Cité, Paris, France.,Assistance Publique - Hôpitaux de Paris (AP-HP), Paris, France
| | - Perrine Frère
- Sorbonne Université, Paris, France.,INSERM UMR_S1155, Tenon Hospital, Paris, France
| | - Juliette Hadchouel
- Institut National de la Santé et de la Recherche Médicale (INSERM), Unit 970, Paris Cardiovascular Research Center, Paris, France. .,Universités Paris-Descartes et Paris-Diderot, Sorbonne Paris Cité, Paris, France. .,Sorbonne Université, Paris, France. .,INSERM UMR_S1155, Tenon Hospital, Paris, France.
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242
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243
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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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244
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Role of ClC-K and barttin in low potassium-induced sodium chloride cotransporter activation and hypertension in mouse kidney. Biosci Rep 2018; 38:BSR20171243. [PMID: 29326302 PMCID: PMC5789154 DOI: 10.1042/bsr20171243] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Revised: 01/04/2018] [Accepted: 01/08/2018] [Indexed: 12/22/2022] Open
Abstract
The sodium chloride cotransporter (NCC) has been identified as a key molecule regulating potassium balance. The mechanisms of NCC regulation during low extracellular potassium concentrations have been studied in vitro. These studies have shown that hyperpolarization increased chloride efflux, leading to the activation of chloride-sensitive with-no-lysine kinase (WNK) kinases and their downstream molecules, including STE20/SPS1-related proline/alanine-rich kinase (SPAK) and NCC. However, this mechanism was not studied in vivo. Previously, we developed the barttin hypomorphic mouse (Bsndneo/neo mice), expressing very low levels of barttin and ClC-K channels, because barttin is an essential β-subunit of ClC-K. In contrast with Bsnd−/− mice, Bsndneo/neo mice survived to adulthood. In Bsndneo/neo mice, SPAK and NCC activation after consuming a low-potassium diet was clearly impaired compared with that in wild-type (WT) mice. In ex vivo kidney slice experiment, the increase in pNCC and SPAK in low-potassium medium was also impaired in Bsndneo/neo mice. Furthermore, increased blood pressure was observed in WT mice fed a high-salt and low-potassium diet, which was not evident in Bsndneo/neo mice. Thus, our study provides in vivo evidence that, in response to a low-potassium diet, ClC-K and barttin play important roles in the activation of the WNK4-SPAK-NCC cascade and blood pressure regulation.
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245
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Abstract
PURPOSE OF REVIEW The paracellular pathway through the tight junction provides an important route for chloride reabsorption in the collecting duct of the kidney. This review describes recent findings of how defects in paracellular chloride permeation pathway may cause kidney diseases and how such a pathway may be regulated to maintain normal chloride homeostasis. RECENT FINDINGS The tight junction in the collecting duct expresses two important claudin genes - claudin-4 and claudin-8. Transgenic knockout of either claudin gene causes hypotension, hypochloremia, and metabolic alkalosis in experimental animals. The claudin-4 mediated chloride permeability can be regulated by a protease endogenously expressed by the collecting duct cell - channel-activating protease 1. Channel-activating protease 1 regulates the intercellular interaction of claudin-4 and its membrane stability. Kelch-like 3, previously identified as a causal gene for Gordon's syndrome, also known as pseudohypoaldosteronism II, directly interacts with claudin-8 and regulates its ubiquitination and degradation. The dominant pseudohypoaldosteronism-II mutation (R528H) in Kelch-like 3 abolishes claudin-8 binding, ubiquitination, and degradation. SUMMARY The paracellular chloride permeation pathway in the kidney is an important but understudied area in nephrology. It plays vital roles in renal salt handling and regulation of extracellular fluid volume and blood pressure. Two claudin proteins, claudin-4 and claudin-8, contribute to the function of this paracellular pathway. Deletion of either claudin protein from the collecting duct causes renal chloride reabsorption defects and low blood pressure. Claudins can be regulated on posttranslational levels by several mechanisms involving protease and ubiquitin ligase. Deregulation of claudins may cause human hypertension as exemplified in the Gordon's syndrome.
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246
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Abstract
PURPOSE OF REVIEW Abundant evidence supports that the NaCl cotransporter (NCC) activity is tightly regulated by the with-no-lysine (WNK) kinases. Here, we summarize the data regarding NCC regulation by WNKs, with a particular emphasis on WNK4. RECENT FINDINGS Several studies involving in-vivo and in-vitro models have provided paradoxical data regarding WNK4 regulation of the NCC. Although some studies show that WNK4 can activate the NCC, other equally compelling studies show that WNK4 inhibits the NCC. Recent studies have shown that WNK4 is regulated by the intracellular chloride concentration ([Cl]i), which could account for these paradoxical results. In conditions of high [Cl]i, WNK4 could act as an inhibitor via heterodimer formation with other WNKs. In contrast, when [Cl]i is low, WNK4 can activate Ste20-related, proline-alanine-rich kinase (SPAK)/oxidative stress responsive kinase 1 (OSR1) and thus the NCC. Modulation of WNK4 by [Cl]i has been shown to account for the potassium-sensing properties of the distal convoluted tubule. Other regulators of WNK4 include hormones and ubiquitination. SUMMARY Modulation of WNK4 activity by [Cl]i can account for its dual role on the NCC, and this has important physiological implications regarding the regulation of extracellular potassium concentration. Defective regulation of WNKs by ubiquitination explains most cases of familial hyperkalemic hypertension.
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247
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Freitas SRS. Molecular Genetics of Salt-Sensitivity and Hypertension: Role of Renal Epithelial Sodium Channel Genes. Am J Hypertens 2018; 31:172-174. [PMID: 29045522 DOI: 10.1093/ajh/hpx184] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Accepted: 10/06/2017] [Indexed: 12/24/2022] Open
Affiliation(s)
- Silvia R S Freitas
- Department of Biology, Center of Higher Education in Tefé, Amazonas State University, Amazonas, Brazil
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248
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Abstract
Caveolin-1 (Cav1) is essential for the formation of caveolae. Little is known about their functional role in the kidney. We tested the hypothesis that caveolae modulate renal salt and water reabsorption. Wild-type (WT) and Cav1-deficient (Cav1−/−) mice were studied. Cav1 expression and caveolae formation were present in vascular cells, late distal convoluted tubule and principal connecting tubule and collecting duct cells of WT but not Cav1−/− kidneys. Urinary sodium excretion was increased by 94% and urine flow by 126% in Cav1−/− mice (p < 0.05). A decrease in activating phosphorylation of the Na-Cl cotransporter (NCC) of the distal convoluted tubule was recorded in Cav1−/− compared to WT kidneys (−40%; p < 0.05). Isolated intrarenal arteries from Cav1−/− mice revealed a fourfold reduction in sensitivity to phenylephrine (p < 0.05). A significantly diminished maximal contractile response (−13%; p < 0.05) was suggestive of enhanced nitric oxide (NO) availability. In line with this, the abundance of endothelial NO synthase (eNOS) was increased in Cav1−/− kidneys +213%; p < 0.05) and cultured caveolae-deprived cells showed intracellular accumulation of eNOS, compared to caveolae-intact controls. Our results suggest that renal caveolae help to conserve water and electrolytes via modulation of NCC function and regulation of vascular eNOS.
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van der Wijst J, Tutakhel OAZ, Bos C, Danser AHJ, Hoorn EJ, Hoenderop JGJ, Bindels RJM. Effects of a high-sodium/low-potassium diet on renal calcium, magnesium, and phosphate handling. Am J Physiol Renal Physiol 2018; 315:F110-F122. [PMID: 29357414 DOI: 10.1152/ajprenal.00379.2017] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The distal convoluted tubule (DCT) of the kidney plays an important role in blood pressure regulation by modulating Na+ reabsorption via the Na+-Cl- cotransporter (NCC). A diet containing high salt (NaCl) and low K+ activates NCC, thereby causing Na+ retention and a rise in blood pressure. Since high blood pressure, hypertension, is associated with changes in serum calcium (Ca2+) and magnesium (Mg2+) levels, we hypothesized that dietary Na+ and K+ intake affects Ca2+ and Mg2+ transport in the DCT. Therefore, the present study aimed to investigate the effect of a high-Na+/low-K+ diet on renal Ca2+ and Mg2+ handling. Mice were divided in four groups and fed a normal-Na+/normal-K+, normal-Na+/low-K+, high-Na+/normal-K+, or high-Na+/low-K+ diet for 4 days. Serum and urine were collected for electrolyte and hormone analysis. Gene and protein expression of electrolyte transporters were assessed in kidney and intestine by qPCR and immunoblotting. Whereas Mg2+ homeostasis was not affected, the mice had elevated urinary Ca2+ and phosphate (Pi) excretion upon high Na+ intake, as well as significantly lower serum Ca2+ levels in the high-Na+/low-K+ group. Alterations in the gene and protein expression of players involved in Ca2+ and Pi transport indicate that reabsorption in the proximal tubular and TAL is affected, while inducing a compensatory response in the DCT. These effects may contribute to the negative health impact of a high-salt diet, including kidney stone formation, chronic kidney disease, and loss of bone mineral density.
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Affiliation(s)
- Jenny van der Wijst
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center , Nijmegen , The Netherlands
| | - Omar A Z Tutakhel
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center , Nijmegen , The Netherlands
| | - Caro Bos
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center , Nijmegen , The Netherlands
| | - Alexander H J Danser
- Division of Pharmacology and Vascular Medicine, Department of Internal Medicine, Erasmus MC, Rotterdam , The Netherlands
| | - Ewout J Hoorn
- Division of Nephrology and Transplantation, Department of Internal Medicine, Erasmus University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Joost G J Hoenderop
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center , Nijmegen , The Netherlands
| | - René J M Bindels
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center , Nijmegen , The Netherlands
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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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