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Lou Y, Zhang F, Luo Y, Wang L, Huang S, Jin F. Serum and Glucocorticoid Regulated Kinase 1 in Sodium Homeostasis. Int J Mol Sci 2016; 17:ijms17081307. [PMID: 27517916 PMCID: PMC5000704 DOI: 10.3390/ijms17081307] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Revised: 08/02/2016] [Accepted: 08/03/2016] [Indexed: 12/13/2022] Open
Abstract
The ubiquitously expressed serum and glucocorticoid regulated kinase 1 (SGK1) is tightly regulated by osmotic and hormonal signals, including glucocorticoids and mineralocorticoids. Recently, SGK1 has been implicated as a signal hub for the regulation of sodium transport. SGK1 modulates the activities of multiple ion channels and carriers, such as epithelial sodium channel (ENaC), voltage-gated sodium channel (Nav1.5), sodium hydrogen exchangers 1 and 3 (NHE1 and NHE3), sodium-chloride symporter (NCC), and sodium-potassium-chloride cotransporter 2 (NKCC2); as well as the sodium-potassium adenosine triphosphatase (Na+/K+-ATPase) and type A natriuretic peptide receptor (NPR-A). Accordingly, SGK1 is implicated in the physiology and pathophysiology of Na+ homeostasis. Here, we focus particularly on recent findings of SGK1’s involvement in Na+ transport in renal sodium reabsorption, hormone-stimulated salt appetite and fluid balance and discuss the abnormal SGK1-mediated Na+ reabsorption in hypertension, heart disease, edema with diabetes, and embryo implantation failure.
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Affiliation(s)
- Yiyun Lou
- Department of Reproductive Endocrinology, Women's Hospital, School of Medicine, Zhejiang University, Hangzhou 310006, Zhejiang, China.
- Department of Gynaecology, Hangzhou Hospital of Traditional Chinese Medicine, Hangzhou 310007, Zhejiang, China.
| | - Fan Zhang
- Department of Reproductive Endocrinology, Women's Hospital, School of Medicine, Zhejiang University, Hangzhou 310006, Zhejiang, China.
| | - Yuqin Luo
- Department of Reproductive Endocrinology, Women's Hospital, School of Medicine, Zhejiang University, Hangzhou 310006, Zhejiang, China.
| | - Liya Wang
- Department of Reproductive Endocrinology, Women's Hospital, School of Medicine, Zhejiang University, Hangzhou 310006, Zhejiang, China.
| | - Shisi Huang
- Department of Reproductive Endocrinology, Women's Hospital, School of Medicine, Zhejiang University, Hangzhou 310006, Zhejiang, China.
| | - Fan Jin
- Department of Reproductive Endocrinology, Women's Hospital, School of Medicine, Zhejiang University, Hangzhou 310006, Zhejiang, China.
- Key Laboratory of Reproductive Genetics, National Ministry of Education (Zhejiang University), Women's Reproductive Healthy Laboratory of Zhejiang Province, Hangzhou 310058, Zhejiang, China.
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Hughes AD. How do thiazide and thiazide-like diuretics lower blood pressure? J Renin Angiotensin Aldosterone Syst 2016; 5:155-60. [PMID: 15803433 DOI: 10.3317/jraas.2004.034] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Thiazide diuretics are widely used for the treatment of hypertension, but the mechanism by which these drugs lower blood pressure in the long term remains unknown. This article reviews current knowledge about the hypotensive actions of thiazides and thiazide-like diuretics and discusses possible mechanisms of action.
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Affiliation(s)
- Alun D Hughes
- Clinical Pharmacology, Faculty of Medicine, Imperial College London, London W21NY, UK.
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53
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The sodium chloride cotransporter (NCC) and epithelial sodium channel (ENaC) associate. Biochem J 2016; 473:3237-52. [PMID: 27422782 DOI: 10.1042/bcj20160312] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Accepted: 07/11/2016] [Indexed: 11/17/2022]
Abstract
The thiazide-sensitive sodium chloride cotransporter (NCC) and the epithelial sodium channel (ENaC) are two of the most important determinants of salt balance and thus systemic blood pressure. Abnormalities in either result in profound changes in blood pressure. There is one segment of the nephron where these two sodium transporters are coexpressed, the second part of the distal convoluted tubule. This is a key part of the aldosterone-sensitive distal nephron, the final regulator of salt handling in the kidney. Aldosterone is the key hormonal regulator for both of these proteins. Despite these shared regulators and coexpression in a key nephron segment, associations between these proteins have not been investigated. After confirming apical localization of these proteins, we demonstrated the presence of functional transport proteins and native association by blue native PAGE. Extensive coimmunoprecipitation experiments demonstrated a consistent interaction of NCC with α- and γ-ENaC. Mammalian two-hybrid studies demonstrated direct binding of NCC to ENaC subunits. Fluorescence resonance energy transfer and immunogold EM studies confirmed that these transport proteins are within appropriate proximity for direct binding. Additionally, we demonstrate that there are functional consequences of this interaction, with inhibition of NCC affecting the function of ENaC. This novel finding of an association between ENaC and NCC could alter our understanding of salt transport in the distal tubule.
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Wolley MJ, Wu A, Xu S, Gordon RD, Fenton RA, Stowasser M. In Primary Aldosteronism, Mineralocorticoids Influence Exosomal Sodium-Chloride Cotransporter Abundance. J Am Soc Nephrol 2016; 28:56-63. [PMID: 27381844 DOI: 10.1681/asn.2015111221] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2015] [Accepted: 05/31/2016] [Indexed: 01/21/2023] Open
Abstract
Distal tubular sodium retention is a potent driver of hypertension, and the thiazide-sensitive sodium-chloride cotransporter (NCC) has a key role in this process. In humans, factors regulating NCC are unclear, but in animal models, aldosterone is a potent regulator, possibly via effects on plasma potassium. We studied the effects of the mineralocorticoid fludrocortisone on the abundance of NCC and its phosphorylated form (pNCC) as well as WNK lysine deficient protein kinase 4 (WNK4) and STE20/SPS1-related, proline alanine-rich kinase (SPAK) in human urinary exosomes. We isolated exosomes from daily urine samples in 25 patients undergoing fludrocortisone suppression testing (100 μg every 6 hours for 4 days) to diagnose or exclude primary aldosteronism. Over the course of the test, NCC levels increased 3.68-fold (P<0.01) and pNCC levels increased 2.73-fold (P<0.01) relative to baseline. The ratio of pNCC/NCC dropped by 48% (P<0.01). The abundance of WNK4 increased 3.23-fold (P<0.01), but SPAK abundance did not change significantly (P=0.14). Plasma potassium concentration strongly and negatively correlated with pNCC, NCC, and WNK4 abundance (P<0.001 for all). This study shows that, in humans, mineralocorticoid administration is associated with a rapid increase in abundance of NCC and pNCC, possibly via the WNK pathway. These effects may be driven by changes in plasma potassium.
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Affiliation(s)
- Martin J Wolley
- Endocrine Hypertension Research Centre, University of Queensland School of Medicine, Greenslopes and Princess Alexandra Hospitals, Brisbane, Australia.,Department of Nephrology, Royal Brisbane and Women's Hospital, Brisbane, Australia; and
| | - Aihua Wu
- Endocrine Hypertension Research Centre, University of Queensland School of Medicine, Greenslopes and Princess Alexandra Hospitals, Brisbane, Australia
| | - Shengxin Xu
- Endocrine Hypertension Research Centre, University of Queensland School of Medicine, Greenslopes and Princess Alexandra Hospitals, Brisbane, Australia
| | - Richard D Gordon
- Endocrine Hypertension Research Centre, University of Queensland School of Medicine, Greenslopes and Princess Alexandra Hospitals, Brisbane, Australia
| | - Robert A Fenton
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Michael Stowasser
- Endocrine Hypertension Research Centre, University of Queensland School of Medicine, Greenslopes and Princess Alexandra Hospitals, Brisbane, Australia;
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55
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[Gordon syndrome: The importance of measuring blood pressure in children]. Arch Pediatr 2016; 23:827-31. [PMID: 27369102 DOI: 10.1016/j.arcped.2016.05.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2015] [Revised: 01/10/2016] [Accepted: 05/12/2016] [Indexed: 11/21/2022]
Abstract
Gordon's syndrome, or type II pseudo-hypoaldosteronism, is a rare cause of arterial hypertension in children. However, it is important to diagnose this syndrome because of the spectacular efficacy of thiazide diuretics. The typical clinical picture of Gordon syndrome includes, apart from arterial hypertension and dyskaliemia, hyperchloremia metabolic acidosis, hypercalciuria, a low rate of renin, and most frequently, a normal or high rate of aldosterone. Dental abnormalities and growth retardation can also be associated. In most cases, it is inherited in an autosomal dominant pattern. We report on a 7-year-old girl who was discovered with arterial hypertension during a consultation for chronic diarrhea. The association of growth retardation, hyperkaliemia, and metabolic acidosis oriented the diagnosis. Starting a thiazide diuretic helped control the arterial hypertension and the kaliemia in a spectacular manner. The genetic analysis proved the existence of a splice mutation on exon 9 of the CUL3 gene coding for cullin 3. This mutation is de novo.
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Mercado A, de Los Heros P, Melo Z, Chávez-Canales M, Murillo-de-Ozores AR, Moreno E, Bazúa-Valenti S, Vázquez N, Hadchouel J, Gamba G. With no lysine L-WNK1 isoforms are negative regulators of the K+-Cl- cotransporters. Am J Physiol Cell Physiol 2016; 311:C54-66. [PMID: 27170636 PMCID: PMC4967140 DOI: 10.1152/ajpcell.00193.2015] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Accepted: 05/02/2016] [Indexed: 12/11/2022]
Abstract
The K(+)-Cl(-) cotransporters (KCC1-KCC4) encompass a branch of the SLC12 family of electroneutral cation-coupled chloride cotransporters that translocate ions out of the cell to regulate various factors, including cell volume and intracellular chloride concentration, among others. L-WNK1 is an ubiquitously expressed kinase that is activated in response to osmotic stress and intracellular chloride depletion, and it is implicated in two distinct hereditary syndromes: the renal disease pseudohypoaldosteronism type II (PHAII) and the neurological disease hereditary sensory neuropathy 2 (HSN2). The effect of L-WNK1 on KCC activity is unknown. Using Xenopus laevis oocytes and HEK-293 cells, we show that the activation of KCCs by cell swelling was prevented by L-WNK1 coexpression. In contrast, the activity of the Na(+)-K(+)-2Cl(-) cotransporter NKCC1 was remarkably increased with L-WNK1 coexpression. The negative effect of L-WNK1 on the KCCs is kinase dependent. Elimination of the STE20 proline-alanine rich kinase (SPAK)/oxidative stress-responsive kinase (OSR1) binding site or the HQ motif required for the WNK-WNK interaction prevented the effect of L-WNK1 on KCCs, suggesting a required interaction between L-WNK1 molecules and SPAK. Together, our data support that NKCC1 and KCCs are coordinately regulated by L-WNK1 isoforms.
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Affiliation(s)
- Adriana Mercado
- Department of Nephrology, Instituto Nacional de Cardiología Ignacio Chávez, Tlalpan, Mexico City, Mexico
| | - Paola de Los Heros
- División de Investigación, Facultad de Medicina, Universidad Nacional Autónoma de México, Coyoacán, Mexico City, Mexico
| | - Zesergio Melo
- Molecular Physiology Unit, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Tlalpan, Mexico City, Mexico
| | - María Chávez-Canales
- 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; INSERM UMR970-Paris Cardiovascular Research Center, Paris, France; and University Paris-Descartes, Sorbonne Paris Cité, Faculty of Medicine, Paris, France
| | - Adrián R Murillo-de-Ozores
- Molecular Physiology Unit, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Tlalpan, Mexico City, Mexico
| | - Erika Moreno
- Department of Nephrology and Mineral Metabolism, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán. Tlalpan, Mexico City, Mexico
| | - Silvana Bazúa-Valenti
- 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
| | - 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
| | - Juliette Hadchouel
- INSERM UMR970-Paris Cardiovascular Research Center, Paris, France; and University Paris-Descartes, Sorbonne Paris Cité, Faculty of Medicine, Paris, France
| | - Gerardo Gamba
- Molecular Physiology Unit, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Tlalpan, Mexico City, Mexico; Department of Nephrology and Mineral Metabolism, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán. Tlalpan, Mexico City, Mexico;
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57
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Dbouk HA, Huang CL, Cobb MH. Hypertension: the missing WNKs. Am J Physiol Renal Physiol 2016; 311:F16-27. [PMID: 27009339 PMCID: PMC4967160 DOI: 10.1152/ajprenal.00358.2015] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Accepted: 03/16/2016] [Indexed: 12/23/2022] Open
Abstract
The With no Lysine [K] (WNK) family of enzymes are central in the regulation of blood pressure. WNKs have been implicated in hereditary hypertension disorders, mainly through control of the activity and levels of ion cotransporters and channels. Actions of WNKs in the kidney have been heavily investigated, and recent studies have provided insight into not only the regulation of these enzymes but also how mutations in WNKs and their interacting partners contribute to hypertensive disorders. Defining the roles of WNKs in the cardiovascular system will provide clues about additional mechanisms by which WNKs can regulate blood pressure. This review summarizes recent developments in the regulation of the WNK signaling cascade and its role in regulation of blood pressure.
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Affiliation(s)
- Hashem A Dbouk
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, Texas; and
| | - Chou-Long Huang
- Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Melanie H Cobb
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, Texas; and
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58
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Singh M, Singh AK, Pandey P, Chandra S, Singh KA, Gambhir IS. Molecular genetics of essential hypertension. Clin Exp Hypertens 2016; 38:268-77. [PMID: 27028574 DOI: 10.3109/10641963.2015.1116543] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Hypertension is a major public health problem in the developing as well as in developed countries due to its high prevalence and its association with coronary heart disease, renal disease, stroke, peripheral vascular disease, and related disorders. Essential hypertension (EH) is the most common diagnosis in this disease, suggesting that a monocausal etiology has not been identified. However, a number of risk factors associated with EH have also been identified such as age, sex, demographic, environmental, genetic, and vascular factors. Recent advances in molecular biological research had achieved clarifying the molecular basis of Mendelian hypertensive disorders. Molecular genetic studies have now identified mutations in several genes that cause Mendelian forms of hypertension in humans. However, none of the single genetic variants has emerged from linkage or association analyses as consistently related to the blood pressure level in every sample and in all populations. Besides, a number of polymorphisms in candidate genes have been associated with differences in blood pressure. The most prominent candidate has been the polymorphisms in the renin-angiotensin-aldosterone system. In total, EH is likely to be a polygenic disorder that results from inheritance of a number of susceptibility genes and involves multiple environmental determinants. These determinants complicate the study of blood pressure variations in the general population. The complex nature of the hypertension phenotype makes large-scale studies indispensable, when screening of familial and genetic factors was intended. In this review, recent genetic studies exploring the molecular basis of EH, including different molecular pathways, are highlighted.
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Affiliation(s)
- M Singh
- a Department of Medicine, Faculty of Medicine , Institute of Medical Sciences, Banaras Hindu University , Varanasi , India
| | - A K Singh
- b Department of Surgical Oncology, Faculty of Medicine , Institute of Medical Sciences, Banaras Hindu University , Varanasi , India
| | - P Pandey
- a Department of Medicine, Faculty of Medicine , Institute of Medical Sciences, Banaras Hindu University , Varanasi , India
| | - S Chandra
- c Department of Nephrology, Faculty of Medicine , Institute of Medical Sciences, Banaras Hindu University , Varanasi , India
| | - K A Singh
- d Department of Pharmaceutics , Indian Institute of Technology, Banaras Hindu University , Varanasi , India
| | - I S Gambhir
- a Department of Medicine, Faculty of Medicine , Institute of Medical Sciences, Banaras Hindu University , Varanasi , India
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59
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Rafael C, Chavez-Canales M, Hadchouel J. Réabsorption du sel et sécrétion du potassium par le néphron distal. Med Sci (Paris) 2016; 32:274-80. [DOI: 10.1051/medsci/20163203012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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60
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Unique chloride-sensing properties of WNK4 permit the distal nephron to modulate potassium homeostasis. Kidney Int 2016; 89:127-34. [PMID: 26422504 PMCID: PMC4814375 DOI: 10.1038/ki.2015.289] [Citation(s) in RCA: 183] [Impact Index Per Article: 22.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2015] [Revised: 07/13/2015] [Accepted: 07/31/2015] [Indexed: 11/09/2022]
Abstract
Dietary potassium deficiency activates thiazide-sensitive sodium chloride cotransport along the distal nephron. This may explain, in part, the hypertension and cardiovascular mortality observed in individuals who consume a low-potassium diet. Recent data suggest that plasma potassium affects the distal nephron directly by influencing intracellular chloride, an inhibitor of the with-no-lysine kinase (WNK)-Ste20p-related proline- and alanine-rich kinase (SPAK) pathway. As previous studies used extreme dietary manipulations, we sought to determine whether the relationship between potassium and NaCl cotransporter (NCC) is physiologically relevant and clarify the mechanisms involved. We report that modest changes in both dietary and plasma potassium affect NCC in vivo. Kinase assay studies showed that chloride inhibits WNK4 kinase activity at lower concentrations than it inhibits activity of WNK1 or WNK3. Also, chloride inhibited WNK4 within the range of distal cell chloride concentration. Mutation of a previously identified WNK chloride-binding motif converted WNK4 effects on SPAK from inhibitory to stimulatory in mammalian cells. Disruption of this motif in WNKs 1, 3, and 4 had different effects on NCC, consistent with the three WNKs having different chloride sensitivities. Thus, potassium effects on NCC are graded within the physiological range, which explains how unique chloride-sensing properties of WNK4 enable it to mediate effects of potassium on NCC in vivo.
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61
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Webb TN, Carrisoza-Gaytan R, Montalbetti N, Rued A, Roy A, Socovich AM, Subramanya AR, Satlin LM, Kleyman TR, Carattino MD. Cell-specific regulation of L-WNK1 by dietary K. Am J Physiol Renal Physiol 2016; 310:F15-26. [PMID: 26662201 PMCID: PMC4675801 DOI: 10.1152/ajprenal.00226.2015] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Accepted: 10/11/2015] [Indexed: 12/31/2022] Open
Abstract
Flow-induced K(+) secretion in the aldosterone-sensitive distal nephron is mediated by high-conductance Ca(2+)-activated K(+) (BK) channels. Familial hyperkalemic hypertension (pseudohypoaldosteronism type II) is an inherited form of hypertension with decreased K(+) secretion and increased Na(+) reabsorption. This disorder is linked to mutations in genes encoding with-no-lysine kinase 1 (WNK1), WNK4, and Kelch-like 3/Cullin 3, two components of an E3 ubiquitin ligase complex that degrades WNKs. We examined whether the full-length (or "long") form of WNK1 (L-WNK1) affected the expression of BK α-subunits in HEK cells. Overexpression of L-WNK1 promoted a significant increase in BK α-subunit whole cell abundance and functional channel expression. BK α-subunit abundance also increased with coexpression of a kinase dead L-WNK1 mutant (K233M) and with kidney-specific WNK1 (KS-WNK1), suggesting that the catalytic activity of L-WNK1 was not required to increase BK expression. We examined whether dietary K(+) intake affected L-WNK1 expression in the aldosterone-sensitive distal nephron. We found a paucity of L-WNK1 labeling in cortical collecting ducts (CCDs) from rabbits on a low-K(+) diet but observed robust staining for L-WNK1 primarily in intercalated cells when rabbits were fed a high-K(+) diet. Our results and previous findings suggest that L-WNK1 exerts different effects on renal K(+) secretory channels, inhibiting renal outer medullary K(+) channels and activating BK channels. A high-K(+) diet induced an increase in L-WNK1 expression selectively in intercalated cells and may contribute to enhanced BK channel expression and K(+) secretion in CCDs.
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Affiliation(s)
- Tennille N Webb
- Department of Pediatrics, University of Pittsburgh, Pittsburgh, Pennsylvania
| | | | | | - Anna Rued
- Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Ankita Roy
- Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
| | | | - Arohan R Subramanya
- Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania; Department of Cell Biology, University of Pittsburgh, Pittsburgh, Pennsylvania; Veterans Affairs Pittsburgh Healthcare System, Pittsburgh, Pennsylvania
| | - Lisa M Satlin
- Department of Pediatrics, The Icahn School of Medicine at Mount Sinai, New York, New York; and
| | - Thomas R Kleyman
- Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania; Department of Cell Biology, University of Pittsburgh, Pittsburgh, Pennsylvania; Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, Pennsylvania;
| | - Marcelo D Carattino
- Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania; Department of Cell Biology, University of Pittsburgh, Pittsburgh, Pennsylvania
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Carrisoza-Gaytan R, Carattino MD, Kleyman TR, Satlin LM. An unexpected journey: conceptual evolution of mechanoregulated potassium transport in the distal nephron. Am J Physiol Cell Physiol 2015; 310:C243-59. [PMID: 26632600 DOI: 10.1152/ajpcell.00328.2015] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Flow-induced K secretion (FIKS) in the aldosterone-sensitive distal nephron (ASDN) is mediated by large-conductance, Ca(2+)/stretch-activated BK channels composed of pore-forming α-subunits (BKα) and accessory β-subunits. This channel also plays a critical role in the renal adaptation to dietary K loading. Within the ASDN, the cortical collecting duct (CCD) is a major site for the final renal regulation of K homeostasis. Principal cells in the ASDN possess a single apical cilium whereas the surfaces of adjacent intercalated cells, devoid of cilia, are decorated with abundant microvilli and microplicae. Increases in tubular (urinary) flow rate, induced by volume expansion, diuretics, or a high K diet, subject CCD cells to hydrodynamic forces (fluid shear stress, circumferential stretch, and drag/torque on apical cilia and presumably microvilli/microplicae) that are transduced into increases in principal (PC) and intercalated (IC) cell cytoplasmic Ca(2+) concentration that activate apical voltage-, stretch- and Ca(2+)-activated BK channels, which mediate FIKS. This review summarizes studies by ourselves and others that have led to the evolving picture that the BK channel is localized in a macromolecular complex at the apical membrane, composed of mechanosensitive apical Ca(2+) channels and a variety of kinases/phosphatases as well as other signaling molecules anchored to the cytoskeleton, and that an increase in tubular fluid flow rate leads to IC- and PC-specific responses determined, in large part, by the cell-specific composition of the BK channels.
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Affiliation(s)
| | - Marcelo D Carattino
- Renal-Electrolyte Division, Department of Medicine, Pittsburgh, Pennsylvania
| | - Thomas R Kleyman
- Renal-Electrolyte Division, Department of Medicine, Pittsburgh, Pennsylvania
| | - Lisa M Satlin
- Department of Pediatrics, Icahn School of Medicine at Mount Sinai, New York, New York; and
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63
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Hoover RS, Tomilin V, Hanson L, Pochynyuk O, Ko B. PTH modulation of NCC activity regulates TRPV5 Ca2+ reabsorption. Am J Physiol Renal Physiol 2015; 310:F144-51. [PMID: 26608788 DOI: 10.1152/ajprenal.00323.2015] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Accepted: 11/24/2015] [Indexed: 02/02/2023] Open
Abstract
Since parathyroid hormone (PTH) is known to increase transient receptor potential vanilloid (TRPV)5 activity and decrease Na(+)-Cl(-) cotransporter (NCC) activity, we hypothesized that decreased NCC-mediated Na(+) reabsorption contributes to the enhanced TRPV5 Ca(2+) reabsorption seen with PTH. To test this, we used mDCT15 cells expressing functional TRPV5 and ruthenium red-sensitive (45)Ca(2+) uptake. PTH increased (45)Ca(2+) uptake to 8.8 ± 0.7 nmol·mg(-1)·min(-1) (n = 4, P < 0.01) and decreased NCC activity from 75.4 ± 2.7 to 20.3 ± 1.3 nmol·mg(-1)·min(-1) (n = 4, P < 0.01). Knockdown of Ras guanyl-releasing protein (RasGRP)1 had no baseline effect on (45)Ca(2+) uptake but significantly attenuated the response to PTH from a 45% increase (6.0 ± 0.2 to 8.7 ± 0.4 nmol·mg(-1)·min(-1)) in control cells to only 20% in knockdown cells (6.1 ± 0.1 to 7.3 ± 0.2 nmol·mg(-1)·min(-1), n = 4, P < 0.01). Inhibition of PKC and PKA resulted in further attenuation of the PTH effect. RasGRP1 knockdown decreased the magnitude of the TRPV5 response to PTH (7.9 ± 0.1 nmol·mg(-1)·min(-1) for knockdown compared with 9.1 ± 0.1 nmol·mg(-1)·min(-1) in control), and the addition of thiazide eliminated this effect (a nearly identical 9.0 ± 0.1 nmol·mg(-1)·min(-1)). This indicates that functionally active NCC is required for RasGRP1 knockdown to impact the PTH effect on TRPV5 activity. Knockdown of with no lysine kinase (WNK)4 resulted in an attenuation of the increase in PTH-mediated TRPV5 activity. TRPV5 activity increased by 36% compared with 45% in control (n = 4, P < 0.01 between PTH-treated groups). PKC blockade further attenuated the PTH effect, whereas combined PKC and PKA blockade in WNK4KD cells abolished the effect. We conclude that modulation of NCC activity contributes to the response to PTH, implying a role for hormonal modulation of NCC activity in distal Ca(2+) handling.
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Affiliation(s)
- Robert S Hoover
- Division of Nephrology, Department of Medicine, Emory University, Atlanta, Georgia; Atlanta Veteran's Administration Medical Center, Decatur, Georgia
| | - Viktor Tomilin
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center, Houston, Texas; Institute of Cytology, Russian Academy of Sciences, St. Petersburg, Russian Federation; and
| | - Lauren Hanson
- Department of Medicine, University of Chicago, Chicago, Illinois
| | - Oleh Pochynyuk
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center, Houston, Texas
| | - Benjamin Ko
- Department of Medicine, University of Chicago, Chicago, Illinois
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O'Shaughnessy KM. Gordon Syndrome: a continuing story. Pediatr Nephrol 2015; 30:1903-8. [PMID: 25503323 DOI: 10.1007/s00467-014-2956-7] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2014] [Revised: 08/28/2014] [Accepted: 08/29/2014] [Indexed: 01/01/2023]
Abstract
Gordon Syndrome (GS) is a rare familial hypertension syndrome with a characteristic hyperkalaemia which distinguishes it from other syndromic forms of hypertension that typically cause hypokalaemia. Patients with GS respond to aggressive salt-restriction or relatively small doses of thiazide diuretics, which suggests that activation of the thiazide-sensitive Na/Cl cotransporter (NCC) in the distal nephron is to blame. However, the mechanism has proved to be complex. In 2001, mutations in genes encoding two serine/threonine kinases, WNK1 and WNK4, were identified as causing GS. However, it took several years to appreciate that these kinases operated in a cascade with downstream serine/threonine kinases (SPAK and OSR1) actually phosphorylating and activating NCC and the closely related cotransporters NKCC1 and NKCC2. The hyperkalaemia in GS arises from an independent action of WNK1/WNK4 to reduce cell-surface expression of ROMK, the secretory K-channel in the collecting ducts. However, mutations in WNK1/4 are present in a small minority of GS families, and further genes have emerged (CUL3 and KLHL3) that code for Cullin-3 (a scaffold protein in an ubiquitin-E3 ligase) and an adaptor protein, Kelch3, respectively. These new players regulate the ubiquitination and proteasomal degradation of WNK kinases, thereby adding to the complex picture we now have of NCC regulation in the distal nephron.
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Affiliation(s)
- Kevin M O'Shaughnessy
- Division of Experimental Medicine and Immunotherapeutics, Department of Medicine, Addenbrooke's Hospital-University of Cambridge, Cambridge, CB2 2QQ UK.
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Seki G, Nakamura M, Suzuki M, Satoh N, Horita S. Species differences in regulation of renal proximal tubule transport by certain molecules. World J Nephrol 2015; 4:307-312. [PMID: 25949945 PMCID: PMC4419141 DOI: 10.5527/wjn.v4.i2.307] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/25/2014] [Revised: 12/24/2014] [Accepted: 01/20/2015] [Indexed: 02/06/2023] Open
Abstract
Renal proximal tubules (PTs) play important roles in the regulation of acid/base, plasma volume and blood pressure. Recent studies suggest that there are substantial species differences in the regulation of PT transport. For example, thiazolidinediones (TZDs) are widely used for the treatment of type 2 diabetes mellitus, but the use of TZDs is associated with fluid overload. In addition to the transcriptional enhancement of sodium transport in distal nephrons, TZDs rapidly stimulate PT sodium transport via a non-genomic mechanism depending on peroxisome proliferator activated receptor γ/Src/epidermal growth factor receptor (EGFR)/MEK/ERK. In mouse PTs, however, TZDs fail to stimulate PT transport probably due to constitutive activation of Src/EGFR/ERK pathway. This unique activation of Src/ERK may also affect the effect of high concentrations of insulin on mouse PT transport. On the other hand, the effect of angiotensin II (Ang II) on PT transport is known to be biphasic in rabbits, rats, and mice. However, Ang II induces a concentration-dependent, monophasic transport stimulation in human PTs. The contrasting responses to nitric oxide/guanosine 3’,5’-cyclic monophosphate pathway may largely explain these different effects of Ang II on PT transport. In this review, we focus on the recent findings on the species differences in the regulation of PT transport, which may help understand the species-specific mechanisms underlying edema formation and/or hypertension occurrence.
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Huang CL, Cheng CJ. A unifying mechanism for WNK kinase regulation of sodium-chloride cotransporter. Pflugers Arch 2015; 467:2235-41. [PMID: 25904388 DOI: 10.1007/s00424-015-1708-2] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2015] [Revised: 04/14/2015] [Accepted: 04/15/2015] [Indexed: 12/21/2022]
Abstract
Mammalian with-no-lysine [K] (WNK) kinases are a family of four serine-threonine protein kinases, WNK1-4. Mutations of WNK1 and WNK4 in humans cause pseudohypoaldosteronism type II (PHA2), an autosomal-dominant disease characterized by hypertension and hyperkalemia. Increased Na(+) reabsorption through Na(+)-Cl(-) cotransporter (NCC) in the distal convoluted tubule plays an important role in the pathogenesis of hypertension in patients with PHA2. However, how WNK1 and WNK4 regulate NCC and how mutations of WNKs cause activation of NCC have been controversial. Here, we review current state of literature supporting a compelling model that WNK1 and WNK4 both contribute to stimulation of NCC. The precise combined effects of WNK1 and WNK4 on NCC remain unclear but likely are positive rather than antagonistic. The recent discovery that WNK kinases may function as an intracellular chloride sensor adds a new dimension to the physiological role of WNK kinases. Intracellular chloride-dependent regulation of WNK's may underlie the mechanism of regulation of NCC by extracellular K(+). Definite answer yet will require future investigation by tubular perfusion in mice with altered WNK kinase expression.
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Affiliation(s)
- Chou-Long Huang
- Department of Internal Medicine, Division of Nephrology, UT Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX, 75390-8856, USA.
| | - Chih-Jen Cheng
- Department of Medicine, Division of Nephrology, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan
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Mayan H, Carmon V, Oleinikov K, London S, Halevy R, Holtzman EJ, Tenenbaum-Rakover Y, Farfel Z, Hanukoglu A. Hypercalciuria in familial hyperkalemia and hypertension with KLHL3 mutations. Nephron Clin Pract 2015; 130:59-65. [PMID: 25925082 DOI: 10.1159/000381563] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2014] [Accepted: 03/10/2015] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Familial hyperkalemia and hypertension (FHHt) is a rare genetic disorder manifested by hyperkalemia and early hypertension. Hypercalciuria is another accompanying feature. Mutations in WNK4 and WNK1 were found initially, and recently additional mutations were found in two genes, KLHL3 and CUL3, which are components of the Ubiquitin system. It was not reported whether these latter mutations are accompanied by hypercalciuria. METHODS We compared urinary calcium excretion (UCa) in affected subjects with FHHt and KLHL3 mutations, and in their unaffected family members, and in affected subjects with FHHt and WNK4 Q565E mutation. RESULTS Two new families with FHHt including a total number of 23 subjects, 10 of them affected, in whom previously described mutations in KLHL3 (Q309R and R528H) were identified. Presenting features were short stature in the first family, and transient tachypnea of the newborn (TTN) in the second. Affected subjects had hypercalciuria. UCa levels in affected subjects in the two families were significantly higher than in unaffected subjects (0.608 ± 0.196 vs. 0.236 ± 0.053 mmol Ca per mmol creatinine, respectively (p < 0.0001)). Hypercalciuria in FHHt with KLHL3 mutations is less severe than that observed in FHHt with the Q565E WNK4 mutation (0.608 ± 0.196 (n = 10) mmol Ca per mmol creatinine versus 0.860 ± 0.295 (n = 29), respectively (p = 0.0168)). CONCLUSIONS FHHt caused by KLHL3 mutations is accompanied by hypercalciuria as well as hyperkalemia and hypertension. The similar phenomena observed for FHHt caused by WNK4 mutations fits the other evidence that WNK4 mutations are activating, and the aberrant mechanism of calcium handling by the kidney in FHHt.
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Affiliation(s)
- Haim Mayan
- Department of Medicine E, Sheba Medical Center, Tel Hashomer, Israel
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Regulation of blood pressure and renal electrolyte balance by Cullin-RING ligases. Curr Opin Nephrol Hypertens 2015; 23:487-93. [PMID: 24992566 DOI: 10.1097/mnh.0000000000000049] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
PURPOSE OF REVIEW Efforts to explore the pathogenic mechanisms underlying hereditary hypertension caused by a single gene mutation have brought about conceptual advances in our understanding of blood pressure regulation. We here discuss a novel pathogenic mechanism underlying the hereditary hypertensive disease pseudohypoaldosteronism type II (PHAII), caused by mutations in three different genes encoding for Cullin-3, Kelch-like protein 3 (KLHL3), and with-no-lysine kinases (WNKs). RECENT FINDINGS In 2001, mutations in genes encoding for WNKs were identified as being responsible for PHAII. Recent advancements in genetics, in particular whole-exome sequencing, have revealed that mutations in two additional genes encoding for KLHL3 and Cyllin3 also cause PHAII. This discovery contributed to the clarification of the previously unknown regulatory mechanism of WNKs, namely WNK ubiquitination by the KLHL3-Cullin-3 E3 ligase complex. SUMMARY Levels of WNKs within cells are regulated via ubiquitination by the KLHL3-Cullin-3 E3 ligase complex and are important determinants of the activity of the WNK-oxidative stress-responsive gene 1 and Ste20-related proline-alanine-rich kinase-SLC12A transporter signaling cascade. The PHAII-causing mutations in WNK4, KLHL3, and Cullin-3 result in the decreased ubiquitination and increased abundance of WNK4 in the kidney, thereby activating the thiazide-sensitive NaCl cotransporter and causing PHAII.
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KLHL3 regulates paracellular chloride transport in the kidney by ubiquitination of claudin-8. Proc Natl Acad Sci U S A 2015; 112:4340-5. [PMID: 25831548 DOI: 10.1073/pnas.1421441112] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
A rare Mendelian syndrome--pseudohypoaldosteronism type II (PHA-II)--features hypertension, hyperkalemia, and metabolic acidosis. Genetic linkage studies and exome sequencing have identified four genes--with no lysine kinase 1 (wnk1), wnk4, Kelch-like 3 (KLHL3), and Cullin 3 (Cul3)--mutations of which all caused PHA-II phenotypes. The previous hypothesis was that the KLHL3-Cul3 ubiquitin complex acted on the wnk4-wnk1 kinase complex to regulate Na(+)/Cl(-) cotransporter (NCC) mediated salt reabsorption in the distal tubules of the kidney. Here, we report the identification of claudin-8 as a previously unidentified physiologic target for KLHL3 and provide an alternative explanation for the collecting duct's role in PHA-II. Using a tissue-specific KO approach, we have found that deletion of claudin-8 in the collecting duct of mouse kidney caused hypotension, hypokalemia, and metabolic alkalosis, an exact mirror image of PHA-II. Mechanistically, the phenotypes in claudin-8 KO animals were caused by disruption of the claudin-8 interaction with claudin-4, the paracellular chloride channel, and delocalization of claudin-4 from the tight junction. In mouse collecting duct cells, knockdown of KLHL3 profoundly increased the paracellular chloride permeability. Mechanistically, KLHL3 was directly bound to claudin-8, and this binding led to the ubiquitination and degradation of claudin-8. The dominant PHA-II mutation in KLHL3 impaired claudin-8 binding, ubiquitination, and degradation. These findings have attested to the concept that the paracellular pathway is physiologically regulated through the ubiquitination pathway, and its deregulation may lead to diseases of electrolyte and blood pressure imbalances.
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Bazúa-Valenti S, Gamba G. Revisiting the NaCl cotransporter regulation by with-no-lysine kinases. Am J Physiol Cell Physiol 2015; 308:C779-91. [PMID: 25788573 DOI: 10.1152/ajpcell.00065.2015] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Accepted: 03/13/2015] [Indexed: 01/26/2023]
Abstract
The renal thiazide-sensitive Na(+)-Cl(-) cotransporter (NCC) is the salt transporter in the distal convoluted tubule. Its activity is fundamental for defining blood pressure levels. Decreased NCC activity is associated with salt-remediable arterial hypotension with hypokalemia (Gitelman disease), while increased activity results in salt-sensitive arterial hypertension with hyperkalemia (pseudohypoaldosteronism type II; PHAII). The discovery of four different genes causing PHAII revealed a complex multiprotein system that regulates the activity of NCC. Two genes encode for with-no-lysine (K) kinases WNK1 and WNK4, while two encode for kelch-like 3 (KLHL3) and cullin 3 (CUL3) proteins that form a RING type E3 ubiquitin ligase complex. Extensive research has shown that WNK1 and WNK4 are the targets for the KLHL3-CUL3 complex and that WNKs modulate the activity of NCC by means of intermediary Ste20-type kinases known as SPAK or OSR1. The understanding of the effect of WNKs on NCC is a complex issue, but recent evidence discussed in this review suggests that we could be reaching the end of the dark ages regarding this matter.
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Affiliation(s)
- Silvana Bazúa-Valenti
- Molecular Physiology Unit, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán and Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Gerardo Gamba
- Molecular Physiology Unit, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán and Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Mexico City, Mexico
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Nishimoto M, Fujita T. Renal mechanisms of salt-sensitive hypertension: contribution of two steroid receptor-associated pathways. Am J Physiol Renal Physiol 2015; 308:F377-87. [DOI: 10.1152/ajprenal.00477.2013] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Although salt is a major environmental factor in the development of hypertension, the degree of salt sensitivity varies widely among individuals. The mechanisms responsible for this variation remain to be elucidated. Recent studies have revealed the involvement of two important signaling pathways in renal tubules that play key roles in electrolyte balance and the maintenance of normal blood pressure: the β2-adrenergic stimulant-glucocorticoid receptor (GR)-with-no-lysine kinase (WNK)4-Na+-Cl− cotransporter pathway, which is active in distal convoluted tubule (DCT)1, and the Ras-related C3 botulinum toxin substrate (Rac)1-mineralocorticoid receptor (MR) pathway, which is active in DCT2, connecting tubules, and collecting ducts. β2-Adrenergic stimulation due to increased renal sympathetic activity in obesity- and salt-induced hypertension suppresses histone deacetylase 8 activity via cAMP/PKA signaling, increasing the accessibility of GRs to the negative GR response element in the WNK4 promoter. This results in the suppression of WNK4 transcription followed by the activation of Na+-Cl− cotransporters in the DCT and elevated Na+ retention and blood pressure upon salt loading. Rac1 activates MRs, even in the absence of ligand binding, with this activity increased in the presence of ligand. In salt-sensitive animals, Rac1 activation due to salt loading activates MRs in DCT2, connecting tubules, and collecting ducts. Thus, GRs and MRs are independently involved in two pathways responsible for renal Na+ handling and salt-sensitive hypertension. These findings suggest novel therapeutic targets and may lead to the development of diagnostic tools to determine salt sensitivity in hypertensive patients.
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Affiliation(s)
- Mitsuhiro Nishimoto
- Division of Clinical Epigenetics, Research Center for Advanced Science and Technology, The University of Tokyo, Tokyo, Japan
| | - Toshiro Fujita
- Division of Clinical Epigenetics, Research Center for Advanced Science and Technology, The University of Tokyo, Tokyo, Japan
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Ko B, Mistry A, Hanson L, Mallick R, Hoover RS. Mechanisms of angiotensin II stimulation of NCC are time-dependent in mDCT15 cells. Am J Physiol Renal Physiol 2015; 308:F720-7. [PMID: 25651566 DOI: 10.1152/ajprenal.00465.2014] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2014] [Accepted: 01/26/2015] [Indexed: 12/17/2022] Open
Abstract
Angiotensin II (ANG II) increases thiazide-sensitive sodium-chloride cotransporter (NCC) activity both acutely and chronically. ANG II has been implicated as a switch that turns WNK4 from an inhibitor of NCC into an activator of NCC, and ANG II's effect on NCC appears to require WNK4. Chronically, ANG II stimulation of NCC results in an increase in total and phosphorylated NCC, but the role of NCC phosphorylation in acute ANG II actions is unclear. Here, using a mammalian cell model with robust native NCC activity, we corroborate the role that ANG II plays in WNK4 regulation and clarify the role of Ste20-related proline alanine-rich kinase (SPAK)-induced NCC phosphorylation in ANG II action. ANG II was noted to have a biphasic effect on NCC, with a peak increase in NCC activity in the physiologic range of 10(-11) M ANG II. This effect was apparent as early as 15 min and remained sustained through 120 min. These changes correlated with significant increases in NCC surface protein expression. Knockdown of WNK4 expression sharply attenuated the effect of ANG II. SPAK knockdown did not affect ANG II action at early time points (15 and 30 min), but it did attenuate the response at 60 min. Correspondingly, NCC phosphorylation did not increase at 15 or 30 min, but increased significantly at 60 min. We therefore conclude that within minutes of an increase in ANG II, NCC is rapidly trafficked to the cell surface in a phosphorylation-independent but WNK4-dependent manner. Then, after 60 min, ANG II induces SPAK-dependent phosphorylation of NCC.
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Affiliation(s)
- Benjamin Ko
- Department of Medicine, University of Chicago, Chicago, Illinois;
| | - Abinash Mistry
- Division of Nephrology, Department of Medicine, Emory University, Atlanta, Georgia; and
| | - Lauren Hanson
- Department of Medicine, University of Chicago, Chicago, Illinois
| | - Rickta Mallick
- Division of Nephrology, Department of Medicine, Emory University, Atlanta, Georgia; and
| | - Robert S Hoover
- Division of Nephrology, Department of Medicine, Emory University, Atlanta, Georgia; and Atlanta Veteran's Administration Medical Center, Decatur, Georgia
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Penton D, Czogalla J, Loffing J. Dietary potassium and the renal control of salt balance and blood pressure. Pflugers Arch 2015; 467:513-30. [PMID: 25559844 DOI: 10.1007/s00424-014-1673-1] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2014] [Revised: 12/10/2014] [Accepted: 12/11/2014] [Indexed: 01/09/2023]
Abstract
Dietary potassium (K(+)) intake has antihypertensive effects, prevents strokes, and improves cardiovascular outcomes. The underlying mechanism for these beneficial effects of high K(+) diets may include vasodilation, enhanced urine flow, reduced renal renin release, and negative sodium (Na(+)) balance. Indeed, several studies demonstrate that dietary K(+) intake induces renal Na(+) loss despite elevated plasma aldosterone. This review briefly highlights the epidemiological and experimental evidences for the effects of dietary K(+) on arterial blood pressure. It discusses the pivotal role of the renal distal tubule for the regulation of urinary K(+) and Na(+) excretion and blood pressure and highlights that it depends on the coordinated interaction of different nephron portions, epithelial cell types, and various ion channels, transporters, and ATPases. Moreover, we discuss the relevance of aldosterone and aldosterone-independent factors in mediating the effects of an altered K(+) intake on renal K(+) and Na(+) handling. Particular focus is given to findings suggesting that an aldosterone-independent downregulation of the thiazide-sensitive NaCl cotransporter significantly contributes to the natriuretic and antihypertensive effect of a K(+)-rich diet. Last but not least, we refer to the complex signaling pathways enabling the kidney to adapt its function to the homeostatic needs in response to an altered K(+) intake. Future work will have to further address the underlying cellular and molecular mechanism and to elucidate, among others, how an altered dietary K(+) intake is sensed and how this signal is transmitted to the different epithelial cells lining the distal tubule.
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Affiliation(s)
- David Penton
- Institute of Anatomy, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland
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Abstract
The distal convoluted tubule (DCT) is a short nephron segment, interposed between the macula densa and collecting duct. Even though it is short, it plays a key role in regulating extracellular fluid volume and electrolyte homeostasis. DCT cells are rich in mitochondria, and possess the highest density of Na+/K+-ATPase along the nephron, where it is expressed on the highly amplified basolateral membranes. DCT cells are largely water impermeable, and reabsorb sodium and chloride across the apical membrane via electroneurtral pathways. Prominent among this is the thiazide-sensitive sodium chloride cotransporter, target of widely used diuretic drugs. These cells also play a key role in magnesium reabsorption, which occurs predominantly, via a transient receptor potential channel (TRPM6). Human genetic diseases in which DCT function is perturbed have provided critical insights into the physiological role of the DCT, and how transport is regulated. These include Familial Hyperkalemic Hypertension, the salt-wasting diseases Gitelman syndrome and EAST syndrome, and hereditary hypomagnesemias. The DCT is also established as an important target for the hormones angiotensin II and aldosterone; it also appears to respond to sympathetic-nerve stimulation and changes in plasma potassium. Here, we discuss what is currently known about DCT physiology. Early studies that determined transport rates of ions by the DCT are described, as are the channels and transporters expressed along the DCT with the advent of molecular cloning. Regulation of expression and activity of these channels and transporters is also described; particular emphasis is placed on the contribution of genetic forms of DCT dysregulation to our understanding.
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Affiliation(s)
- James A McCormick
- Division of Nephrology & Hypertension, Oregon Health & Science University, & VA Medical Center, Portland, Oregon, United States
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Abstract
Gitelman syndrome (GS) is a salt-wasting tubulointerstitial disease of autosomal recessive inheritance (OMIM613395) caused by genic mutation of SLC12A3, which codes thiazide-sensitive Na-Cl cotransporter (NCCT) gene. The gene mutation of the majority of GS patients is compound heterozygous. This study analyzes two cases of GS gene mutation and the clinical phenotype. Twenty patients of two GS pedigrees underwent direct sequence alignment of 26 exons of SLC12A3 to spot and locate mutant site. Proband A of Pedigree I had three mutant sites: Arg928Cys, a homozygote, missense mutation, and two homozygous silent mutations, Ala122Ala and Thr465Thr, and 8 members of Pedigree I carried Arg928Cy heterozygous mutation. Proband B of Pedigree II had a homozygote, Ser710X, and a termination codon was spotted, which would inevitably be translated into abridged and defective protein, and 7 members had Ser710X heterozygous mutation. The heterozygous mutation carriers of the two pedigrees often have stimulus-controlled hypokalemia after strenuous exercise. The parents of Proband A are cousins, a case of intermarriage. Both probands show hypokalemia, hypochloraemia, hypocalcinuria, hyperreninemia, and hyperaldosteronemia; Proband A has normal serum magnesium and increased urinary sodium excretion, while Proband B has hypomagnesemia and increased urinary magnesium ion excretion. Both probands have normal or lower blood pressure, weakness and numbness of lower extremities, muscular soreness, and occasional palpitations and chest discomfort. Proband A wearies easily and Proband B has occasional joint numbness and pain. These two homozygous mutations are responsible for the morbidity of two GS families and they show heterogenicity of clinical phenotype.
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Affiliation(s)
- Jiewei Luo
- Department of Traditional Chinese Medicine, Fujian Provincial Hospital, Fujian Medical University, Fuzhou 350001, China
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Goodwin JE. Glucocorticoids and the Cardiovascular System. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2015. [DOI: 10.1007/978-1-4939-2895-8_13] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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Bazúa-Valenti S, Chávez-Canales M, Rojas-Vega L, González-Rodríguez X, Vázquez N, Rodríguez-Gama A, Argaiz ER, Melo Z, Plata C, Ellison DH, García-Valdés J, Hadchouel J, Gamba G. The Effect of WNK4 on the Na+-Cl- Cotransporter Is Modulated by Intracellular Chloride. J Am Soc Nephrol 2014; 26:1781-6. [PMID: 25542968 DOI: 10.1681/asn.2014050470] [Citation(s) in RCA: 122] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Accepted: 10/30/2014] [Indexed: 11/03/2022] Open
Abstract
It is widely recognized that the phenotype of familial hyperkalemic hypertension is mainly a consequence of increased activity of the renal Na(+)-Cl(-) cotransporter (NCC) because of altered regulation by with no-lysine-kinase 1 (WNK1) or WNK4. The effect of WNK4 on NCC, however, has been controversial because both inhibition and activation have been reported. It has been recently shown that the long isoform of WNK1 (L-WNK1) is a chloride-sensitive kinase activated by a low Cl(-) concentration. Therefore, we hypothesized that WNK4 effects on NCC could be modulated by intracellular chloride concentration ([Cl(-)]i), and we tested this hypothesis in oocytes injected with NCC cRNA with or without WNK4 cRNA. At baseline in oocytes, [Cl(-)]i was near 50 mM, autophosphorylation of WNK4 was undetectable, and NCC activity was either decreased or unaffected by WNK4. A reduction of [Cl(-)]i, either by low chloride hypotonic stress or coinjection of oocytes with the solute carrier family 26 (anion exchanger)-member 9 (SLC26A9) cRNA, promoted WNK4 autophosphorylation and increased NCC-dependent Na(+) transport in a WNK4-dependent manner. Substitution of the leucine with phenylalanine at residue 322 of WNK4, homologous to the chloride-binding pocket in L-WNK1, converted WNK4 into a constitutively autophosphorylated kinase that activated NCC, even without chloride depletion. Elimination of the catalytic activity (D321A or D321K-K186D) or the autophosphorylation site (S335A) in mutant WNK4-L322F abrogated the positive effect on NCC. These observations suggest that WNK4 can exert differential effects on NCC, depending on the intracellular chloride concentration.
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Affiliation(s)
- Silvana Bazúa-Valenti
- Molecular Physiology Unit, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México and Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Tlalpan, Mexico City, Mexico
| | - María Chávez-Canales
- Molecular Physiology Unit, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México and Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Tlalpan, Mexico City, Mexico
| | - Lorena Rojas-Vega
- Molecular Physiology Unit, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México and Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Tlalpan, Mexico City, Mexico
| | | | - Norma Vázquez
- Molecular Physiology Unit, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México and Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Tlalpan, Mexico City, Mexico
| | - Alejandro Rodríguez-Gama
- Molecular Physiology Unit, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México and Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Tlalpan, Mexico City, Mexico
| | - Eduardo R Argaiz
- Molecular Physiology Unit, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México and Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Tlalpan, Mexico City, Mexico
| | - Zesergio Melo
- Molecular Physiology Unit, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México and Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Tlalpan, Mexico City, Mexico
| | - Consuelo Plata
- Molecular Physiology Unit, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México and Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Tlalpan, Mexico City, Mexico
| | - David H Ellison
- Division of Nephrology and Hypertension, Department of Medicine, Oregon Health and Science University, Portland, OR
| | - Jesús García-Valdés
- Analytical Chemistry Department, Facultad de Química, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Juliette Hadchouel
- INSERM UMR970, Paris Cardiovascular Research Center, Paris, France; and Faculty of Medicine, University Paris-Descartes, Sorbonne Paris City, Paris, France
| | - Gerardo Gamba
- Molecular Physiology Unit, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México and Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Tlalpan, Mexico City, Mexico;
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Johnson RJ, Lanaspa MA, Gabriela Sánchez-Lozada L, Rodriguez-Iturbe B. The discovery of hypertension: evolving views on the role of the kidneys, and current hot topics. Am J Physiol Renal Physiol 2014; 308:F167-78. [PMID: 25377913 DOI: 10.1152/ajprenal.00503.2014] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Primary hypertension is increasingly common and is associated with significant morbidity. Here, we review the history of its discovery and rise during the last century with an emphasis on studies trying to identify its cause. Early studies identified a defect in sodium excretion by the kidney as being central to the pathogenesis. Recent studies have focused on a variety of genetic, congenital (fetal programming), and acquired mechanisms for causing the defect in natriuresis. Certain risk factors are apparent, including genetic polymorphisms that regulate sodium excretion, a congenital reduction in nephron number, obesity and hyperleptinemia, an elevated sympathetic nervous system, diet (salt and fructose), and metabolic (hyperuricemia) mechanisms. The kidney shows evidence for renal arteriolar vasoconstriction, an intrarenal inflammatory response, local oxidative stress, and intrarenal activation of the renin-angiotensin system. Recent studies suggest that intrarenal T cells have an important role in causing hypertension to be persistent, likely due to the induction of a local autoimmune response to neoantigens such as heat shock protein 70 and protein aggregates formed by isoketals resulting from lipid peroxidation. Salt retention due to impairment in pressure-diuresis leads to the release of cardiotonic steroids and central nervous system effects that cause systemic vasoconstriction and a rise in blood pressure. Some recent studies suggest that salt may increase blood pressure not simply by effects on extracellular volume but rather as a consequence of hyperosmolarity. These new insights could lead to new approaches for the prevention and treatment of this important disease.
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Affiliation(s)
- Richard J Johnson
- Division of Renal Diseases and Hypertension, University of Colorado, Denver, Colorado;
| | - Miguel A Lanaspa
- Division of Renal Diseases and Hypertension, University of Colorado, Denver, Colorado
| | - L Gabriela Sánchez-Lozada
- Laboratory of Renal Physiopathology, Instituto Nacional de Cardiología Ignacio Chávez, Mexico City, Mexico; and
| | - Bernardo Rodriguez-Iturbe
- Hospital Universitario y Universidad del Zulia; and Instituto Venezolano de Investigaciones Científicas (IVIC)-Zulia, Maracaibo, Venezuela
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79
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Angiotensin II signaling via protein kinase C phosphorylates Kelch-like 3, preventing WNK4 degradation. Proc Natl Acad Sci U S A 2014; 111:15556-61. [PMID: 25313067 DOI: 10.1073/pnas.1418342111] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Hypertension contributes to the global burden of cardiovascular disease. Increased dietary K(+) reduces blood pressure; however, the mechanism has been obscure. Human genetic studies have suggested that the mechanism is an obligatory inverse relationship between renal salt reabsorption and K(+) secretion. Mutations in the kinases with-no-lysine 4 (WNK4) or WNK1, or in either Cullin 3 (CUL3) or Kelch-like 3 (KLHL3)--components of an E3 ubiquitin ligase complex that targets WNKs for degradation--cause constitutively increased renal salt reabsorption and impaired K(+) secretion, resulting in hypertension and hyperkalemia. The normal mechanisms that regulate the activity of this ubiquitin ligase and levels of WNKs have been unknown. We posited that missense mutations in KLHL3 that impair binding of WNK4 might represent a phenocopy of the normal physiologic response to volume depletion in which salt reabsorption is maximized. We show that KLHL3 is phosphorylated at serine 433 in the Kelch domain (a site frequently mutated in hypertension with hyperkalemia) by protein kinase C in cultured cells and that this phosphorylation prevents WNK4 binding and degradation. This phosphorylation can be induced by angiotensin II (AII) signaling. Consistent with these in vitro observations, AII administration to mice, even in the absence of volume depletion, induces renal KLHL3(S433) phosphorylation and increased levels of both WNK4 and the NaCl cotransporter. Thus, AII, which is selectively induced in volume depletion, provides the signal that prevents CUL3/KLHL3-mediated degradation of WNK4, directing the kidney to maximize renal salt reabsorption while inhibiting K(+) secretion in the setting of volume depletion.
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Guo XG, Ding J, Xu H, Xuan TM, Jin WQ, Yin X, Shang YP, Zhang FR, Zhu JH, Zheng LR. Comprehensive assessment of the association of WNK4 polymorphisms with hypertension: evidence from a meta-analysis. Sci Rep 2014; 4:6507. [PMID: 25266424 PMCID: PMC4195396 DOI: 10.1038/srep06507] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2014] [Accepted: 09/15/2014] [Indexed: 01/01/2023] Open
Abstract
The relationship between with-no-lysine [K] kinase 4 (WNK4) gene polymorphisms and hypertension has been widely investigated, However, the studies yielded contradictory results. To evaluate these inconclusive findings comprehensively, we therefore performed a meta-analysis. Ten articles encompassing 16 independent case-control studies with 6089 hypertensive cases and 4881 normotensive controls were selected for this meta-analysis. Four WNK4 gene polymorphisms were identified (G1155942T, G1156666A, T1155547C, and C6749T). The results showed statistically significant associations of G1155942T polymorphism (allelic genetic model: odds ration or OR = 1.62, 95% confidence interval or CI: 1.11–2.38, P = 0.01; dominant model: OR = 1.85, 95% CI: 1.07–3.19, P = 0.03) and C6749T polymorphism (allele contrast: OR = 2.04, 95% CI: 1.60–2.59, P<0.01; dominant model: OR = 2.04, 95%CI: 1.59–2.62, P<0.01; and homozygous model: OR = 5.01, 95% CI: 1.29–19.54, P = 0.02) with hypertension risk. However, neither C1155547T nor G1156666A was associated significantly with hypertension susceptibility. In conclusion, this meta-analysis suggested that WNK4 G1155942T and C6749T gene polymorphisms may contribute to the susceptibility and development of hypertension. Further well-designed studies with larger sample size are required to elucidate the association of WNK4 gene multiple polymorphisms with hypertension risk.
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Affiliation(s)
- Xiao-gang Guo
- Department of Cardiology, the First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310003, China
| | - Jie Ding
- Department of Cardiology, the First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310003, China
| | - Hui Xu
- 1] Department of Cardiology, the First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310003, China [2] Xiuzhou District, Gaozhao Street Community Health Service Center, Jiaxing 314031, China
| | - Tian-ming Xuan
- Department of Cardiology, the First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310003, China
| | - Wei-quan Jin
- Department of Cardiology, the First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310003, China
| | - Xiang Yin
- Department of Cardiology, the First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310003, China
| | - Yun-peng Shang
- Department of Cardiology, the First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310003, China
| | - Fu-rong Zhang
- Department of Cardiology, the First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310003, China
| | - Jian-hua Zhu
- Department of Cardiology, the First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310003, China
| | - Liang-rong Zheng
- Department of Cardiology, the First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310003, China
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81
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Ronzaud C, Staub O. Ubiquitylation and control of renal Na+ balance and blood pressure. Physiology (Bethesda) 2014; 29:16-26. [PMID: 24382868 DOI: 10.1152/physiol.00021.2013] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Ubiquitylation is crucial for regulating numerous cellular functions. In the kidney, ubiquitylation regulates the epithelial Na(+) channel ENaC. The importance of this process is highlighted in Liddle's syndrome, where mutations interfere with ENaC ubiquitylation, resulting in constitutive Na(+) reabsorption and hypertension. There is emerging evidence that NCC, involved in hypertensive diseases, is also regulated by ubiquitylation. Here, we discuss the current knowledge and recent findings in this field.
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Affiliation(s)
- Caroline Ronzaud
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland
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82
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Zhang C, Wang L, Zhang J, Su XT, Lin DH, Scholl UI, Giebisch G, Lifton RP, Wang WH. KCNJ10 determines the expression of the apical Na-Cl cotransporter (NCC) in the early distal convoluted tubule (DCT1). Proc Natl Acad Sci U S A 2014; 111:11864-9. [PMID: 25071208 PMCID: PMC4136599 DOI: 10.1073/pnas.1411705111] [Citation(s) in RCA: 120] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The renal phenotype induced by loss-of-function mutations of inwardly rectifying potassium channel (Kir), Kcnj10 (Kir4.1), includes salt wasting, hypomagnesemia, metabolic alkalosis and hypokalemia. However, the mechanism by which Kir.4.1 mutations cause the tubulopathy is not completely understood. Here we demonstrate that Kcnj10 is a main contributor to the basolateral K conductance in the early distal convoluted tubule (DCT1) and determines the expression of the apical Na-Cl cotransporter (NCC) in the DCT. Immunostaining demonstrated Kcnj10 and Kcnj16 were expressed in the basolateral membrane of DCT, and patch-clamp studies detected a 40-pS K channel in the basolateral membrane of the DCT1 of p8/p10 wild-type Kcnj10(+/+) mice (WT). This 40-pS K channel is absent in homozygous Kcnj10(-/-) (knockout) mice. The disruption of Kcnj10 almost completely eliminated the basolateral K conductance and decreased the negativity of the cell membrane potential in DCT1. Moreover, the lack of Kcnj10 decreased the basolateral Cl conductance, inhibited the expression of Ste20-related proline-alanine-rich kinase and diminished the apical NCC expression in DCT. We conclude that Kcnj10 plays a dominant role in determining the basolateral K conductance and membrane potential of DCT1 and that the basolateral K channel activity in the DCT determines the apical NCC expression possibly through a Ste20-related proline-alanine-rich kinase-dependent mechanism.
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Affiliation(s)
- Chengbiao Zhang
- Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical College, Xuzhou 221002, China;Department of Pharmacology, New York Medical College, Valhalla, NY 10595; and
| | - Lijun Wang
- Department of Pharmacology, New York Medical College, Valhalla, NY 10595; and
| | - Junhui Zhang
- Department of Genetics, Howard Hughes Medical Institute, and
| | - Xiao-Tong Su
- Department of Pharmacology, New York Medical College, Valhalla, NY 10595; and
| | - Dao-Hong Lin
- Department of Pharmacology, New York Medical College, Valhalla, NY 10595; and
| | - Ute I Scholl
- Department of Genetics, Howard Hughes Medical Institute, and
| | - Gerhard Giebisch
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT 06510
| | | | - Wen-Hui Wang
- Department of Pharmacology, New York Medical College, Valhalla, NY 10595; and
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83
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Chávez-Canales M, Zhang C, Soukaseum C, Moreno E, Pacheco-Alvarez D, Vidal-Petiot E, Castañeda-Bueno M, Vázquez N, Rojas-Vega L, Meermeier NP, Rogers S, Jeunemaitre X, Yang CL, Ellison DH, Gamba G, Hadchouel J. WNK-SPAK-NCC cascade revisited: WNK1 stimulates the activity of the Na-Cl cotransporter via SPAK, an effect antagonized by WNK4. Hypertension 2014; 64:1047-53. [PMID: 25113964 DOI: 10.1161/hypertensionaha.114.04036] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The with-no-lysine (K) kinases, WNK1 and WNK4, are key regulators of blood pressure. Their mutations lead to familial hyperkalemic hypertension (FHHt), associated with an activation of the Na-Cl cotransporter (NCC). Although it is clear that WNK4 mutants activate NCC via Ste20 proline-alanine-rich kinase, the mechanisms responsible for WNK1-related FHHt and alterations in NCC activity are not as clear. We tested whether WNK1 modulates NCC through WNK4, as predicted by some models, by crossing our recently developed WNK1-FHHt mice (WNK1(+/FHHt)) with WNK4(-/-) mice. Surprisingly, the activated NCC, hypertension, and hyperkalemia of WNK1(+/FHHt) mice remain in the absence of WNK4. We demonstrate that WNK1 powerfully stimulates NCC in a WNK4-independent and Ste20 proline-alanine-rich kinase-dependent manner. Moreover, WNK4 decreases the WNK1 and WNK3-mediated activation of NCC. Finally, the formation of oligomers of WNK kinases through their C-terminal coiled-coil domain is essential for their activity toward NCC. In conclusion, WNK kinases form a network in which WNK4 associates with WNK1 and WNK3 to regulate NCC.
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Affiliation(s)
- María Chávez-Canales
- From the Molecular Physiology Unit, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, México City, Mexico (M.C.-C., M.C.-B., N.V., L.R.-V., G.G.); Department of Nephrology and Mineral Metabolism, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico (M.C.-C., E.M., M.C.-B., N.V., L.R.-V., G.G.); Division of Nephrology and Hypertension, Oregon Health and Science University, Portland (C.Z., N.P.M., S.R., X.J., C.-L.Y., D.H.E.); INSERM UMR970-Paris Cardiovascular Research Center, Paris, France (C.S., E.V.-P., X.J., J.H.); Faculty of Medicine, University Paris-Descartes, Sorbonne Paris Cité, Paris, France (C.S., E.V.-P., J.H.); Escuela de Medicina, Universidad Panamericana, Mexico City, Mexico (D.P.-A.); AP-HP, Department of Genetics, Hôpital Européen Georges Pompidou, Paris, France (X.J.); and Veterans Affairs Medical Center, Portland, OR (D.H.E.)
| | - Chong Zhang
- From the Molecular Physiology Unit, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, México City, Mexico (M.C.-C., M.C.-B., N.V., L.R.-V., G.G.); Department of Nephrology and Mineral Metabolism, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico (M.C.-C., E.M., M.C.-B., N.V., L.R.-V., G.G.); Division of Nephrology and Hypertension, Oregon Health and Science University, Portland (C.Z., N.P.M., S.R., X.J., C.-L.Y., D.H.E.); INSERM UMR970-Paris Cardiovascular Research Center, Paris, France (C.S., E.V.-P., X.J., J.H.); Faculty of Medicine, University Paris-Descartes, Sorbonne Paris Cité, Paris, France (C.S., E.V.-P., J.H.); Escuela de Medicina, Universidad Panamericana, Mexico City, Mexico (D.P.-A.); AP-HP, Department of Genetics, Hôpital Européen Georges Pompidou, Paris, France (X.J.); and Veterans Affairs Medical Center, Portland, OR (D.H.E.)
| | - Christelle Soukaseum
- From the Molecular Physiology Unit, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, México City, Mexico (M.C.-C., M.C.-B., N.V., L.R.-V., G.G.); Department of Nephrology and Mineral Metabolism, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico (M.C.-C., E.M., M.C.-B., N.V., L.R.-V., G.G.); Division of Nephrology and Hypertension, Oregon Health and Science University, Portland (C.Z., N.P.M., S.R., X.J., C.-L.Y., D.H.E.); INSERM UMR970-Paris Cardiovascular Research Center, Paris, France (C.S., E.V.-P., X.J., J.H.); Faculty of Medicine, University Paris-Descartes, Sorbonne Paris Cité, Paris, France (C.S., E.V.-P., J.H.); Escuela de Medicina, Universidad Panamericana, Mexico City, Mexico (D.P.-A.); AP-HP, Department of Genetics, Hôpital Européen Georges Pompidou, Paris, France (X.J.); and Veterans Affairs Medical Center, Portland, OR (D.H.E.)
| | - Erika Moreno
- From the Molecular Physiology Unit, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, México City, Mexico (M.C.-C., M.C.-B., N.V., L.R.-V., G.G.); Department of Nephrology and Mineral Metabolism, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico (M.C.-C., E.M., M.C.-B., N.V., L.R.-V., G.G.); Division of Nephrology and Hypertension, Oregon Health and Science University, Portland (C.Z., N.P.M., S.R., X.J., C.-L.Y., D.H.E.); INSERM UMR970-Paris Cardiovascular Research Center, Paris, France (C.S., E.V.-P., X.J., J.H.); Faculty of Medicine, University Paris-Descartes, Sorbonne Paris Cité, Paris, France (C.S., E.V.-P., J.H.); Escuela de Medicina, Universidad Panamericana, Mexico City, Mexico (D.P.-A.); AP-HP, Department of Genetics, Hôpital Européen Georges Pompidou, Paris, France (X.J.); and Veterans Affairs Medical Center, Portland, OR (D.H.E.)
| | - Diana Pacheco-Alvarez
- From the Molecular Physiology Unit, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, México City, Mexico (M.C.-C., M.C.-B., N.V., L.R.-V., G.G.); Department of Nephrology and Mineral Metabolism, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico (M.C.-C., E.M., M.C.-B., N.V., L.R.-V., G.G.); Division of Nephrology and Hypertension, Oregon Health and Science University, Portland (C.Z., N.P.M., S.R., X.J., C.-L.Y., D.H.E.); INSERM UMR970-Paris Cardiovascular Research Center, Paris, France (C.S., E.V.-P., X.J., J.H.); Faculty of Medicine, University Paris-Descartes, Sorbonne Paris Cité, Paris, France (C.S., E.V.-P., J.H.); Escuela de Medicina, Universidad Panamericana, Mexico City, Mexico (D.P.-A.); AP-HP, Department of Genetics, Hôpital Européen Georges Pompidou, Paris, France (X.J.); and Veterans Affairs Medical Center, Portland, OR (D.H.E.)
| | - Emmanuelle Vidal-Petiot
- From the Molecular Physiology Unit, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, México City, Mexico (M.C.-C., M.C.-B., N.V., L.R.-V., G.G.); Department of Nephrology and Mineral Metabolism, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico (M.C.-C., E.M., M.C.-B., N.V., L.R.-V., G.G.); Division of Nephrology and Hypertension, Oregon Health and Science University, Portland (C.Z., N.P.M., S.R., X.J., C.-L.Y., D.H.E.); INSERM UMR970-Paris Cardiovascular Research Center, Paris, France (C.S., E.V.-P., X.J., J.H.); Faculty of Medicine, University Paris-Descartes, Sorbonne Paris Cité, Paris, France (C.S., E.V.-P., J.H.); Escuela de Medicina, Universidad Panamericana, Mexico City, Mexico (D.P.-A.); AP-HP, Department of Genetics, Hôpital Européen Georges Pompidou, Paris, France (X.J.); and Veterans Affairs Medical Center, Portland, OR (D.H.E.)
| | - María Castañeda-Bueno
- From the Molecular Physiology Unit, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, México City, Mexico (M.C.-C., M.C.-B., N.V., L.R.-V., G.G.); Department of Nephrology and Mineral Metabolism, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico (M.C.-C., E.M., M.C.-B., N.V., L.R.-V., G.G.); Division of Nephrology and Hypertension, Oregon Health and Science University, Portland (C.Z., N.P.M., S.R., X.J., C.-L.Y., D.H.E.); INSERM UMR970-Paris Cardiovascular Research Center, Paris, France (C.S., E.V.-P., X.J., J.H.); Faculty of Medicine, University Paris-Descartes, Sorbonne Paris Cité, Paris, France (C.S., E.V.-P., J.H.); Escuela de Medicina, Universidad Panamericana, Mexico City, Mexico (D.P.-A.); AP-HP, Department of Genetics, Hôpital Européen Georges Pompidou, Paris, France (X.J.); and Veterans Affairs Medical Center, Portland, OR (D.H.E.)
| | - Norma Vázquez
- From the Molecular Physiology Unit, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, México City, Mexico (M.C.-C., M.C.-B., N.V., L.R.-V., G.G.); Department of Nephrology and Mineral Metabolism, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico (M.C.-C., E.M., M.C.-B., N.V., L.R.-V., G.G.); Division of Nephrology and Hypertension, Oregon Health and Science University, Portland (C.Z., N.P.M., S.R., X.J., C.-L.Y., D.H.E.); INSERM UMR970-Paris Cardiovascular Research Center, Paris, France (C.S., E.V.-P., X.J., J.H.); Faculty of Medicine, University Paris-Descartes, Sorbonne Paris Cité, Paris, France (C.S., E.V.-P., J.H.); Escuela de Medicina, Universidad Panamericana, Mexico City, Mexico (D.P.-A.); AP-HP, Department of Genetics, Hôpital Européen Georges Pompidou, Paris, France (X.J.); and Veterans Affairs Medical Center, Portland, OR (D.H.E.)
| | - Lorena Rojas-Vega
- From the Molecular Physiology Unit, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, México City, Mexico (M.C.-C., M.C.-B., N.V., L.R.-V., G.G.); Department of Nephrology and Mineral Metabolism, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico (M.C.-C., E.M., M.C.-B., N.V., L.R.-V., G.G.); Division of Nephrology and Hypertension, Oregon Health and Science University, Portland (C.Z., N.P.M., S.R., X.J., C.-L.Y., D.H.E.); INSERM UMR970-Paris Cardiovascular Research Center, Paris, France (C.S., E.V.-P., X.J., J.H.); Faculty of Medicine, University Paris-Descartes, Sorbonne Paris Cité, Paris, France (C.S., E.V.-P., J.H.); Escuela de Medicina, Universidad Panamericana, Mexico City, Mexico (D.P.-A.); AP-HP, Department of Genetics, Hôpital Européen Georges Pompidou, Paris, France (X.J.); and Veterans Affairs Medical Center, Portland, OR (D.H.E.)
| | - Nicholas P Meermeier
- From the Molecular Physiology Unit, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, México City, Mexico (M.C.-C., M.C.-B., N.V., L.R.-V., G.G.); Department of Nephrology and Mineral Metabolism, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico (M.C.-C., E.M., M.C.-B., N.V., L.R.-V., G.G.); Division of Nephrology and Hypertension, Oregon Health and Science University, Portland (C.Z., N.P.M., S.R., X.J., C.-L.Y., D.H.E.); INSERM UMR970-Paris Cardiovascular Research Center, Paris, France (C.S., E.V.-P., X.J., J.H.); Faculty of Medicine, University Paris-Descartes, Sorbonne Paris Cité, Paris, France (C.S., E.V.-P., J.H.); Escuela de Medicina, Universidad Panamericana, Mexico City, Mexico (D.P.-A.); AP-HP, Department of Genetics, Hôpital Européen Georges Pompidou, Paris, France (X.J.); and Veterans Affairs Medical Center, Portland, OR (D.H.E.)
| | - Shaunessy Rogers
- From the Molecular Physiology Unit, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, México City, Mexico (M.C.-C., M.C.-B., N.V., L.R.-V., G.G.); Department of Nephrology and Mineral Metabolism, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico (M.C.-C., E.M., M.C.-B., N.V., L.R.-V., G.G.); Division of Nephrology and Hypertension, Oregon Health and Science University, Portland (C.Z., N.P.M., S.R., X.J., C.-L.Y., D.H.E.); INSERM UMR970-Paris Cardiovascular Research Center, Paris, France (C.S., E.V.-P., X.J., J.H.); Faculty of Medicine, University Paris-Descartes, Sorbonne Paris Cité, Paris, France (C.S., E.V.-P., J.H.); Escuela de Medicina, Universidad Panamericana, Mexico City, Mexico (D.P.-A.); AP-HP, Department of Genetics, Hôpital Européen Georges Pompidou, Paris, France (X.J.); and Veterans Affairs Medical Center, Portland, OR (D.H.E.)
| | - Xavier Jeunemaitre
- From the Molecular Physiology Unit, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, México City, Mexico (M.C.-C., M.C.-B., N.V., L.R.-V., G.G.); Department of Nephrology and Mineral Metabolism, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico (M.C.-C., E.M., M.C.-B., N.V., L.R.-V., G.G.); Division of Nephrology and Hypertension, Oregon Health and Science University, Portland (C.Z., N.P.M., S.R., X.J., C.-L.Y., D.H.E.); INSERM UMR970-Paris Cardiovascular Research Center, Paris, France (C.S., E.V.-P., X.J., J.H.); Faculty of Medicine, University Paris-Descartes, Sorbonne Paris Cité, Paris, France (C.S., E.V.-P., J.H.); Escuela de Medicina, Universidad Panamericana, Mexico City, Mexico (D.P.-A.); AP-HP, Department of Genetics, Hôpital Européen Georges Pompidou, Paris, France (X.J.); and Veterans Affairs Medical Center, Portland, OR (D.H.E.)
| | - Chao-Ling Yang
- From the Molecular Physiology Unit, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, México City, Mexico (M.C.-C., M.C.-B., N.V., L.R.-V., G.G.); Department of Nephrology and Mineral Metabolism, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico (M.C.-C., E.M., M.C.-B., N.V., L.R.-V., G.G.); Division of Nephrology and Hypertension, Oregon Health and Science University, Portland (C.Z., N.P.M., S.R., X.J., C.-L.Y., D.H.E.); INSERM UMR970-Paris Cardiovascular Research Center, Paris, France (C.S., E.V.-P., X.J., J.H.); Faculty of Medicine, University Paris-Descartes, Sorbonne Paris Cité, Paris, France (C.S., E.V.-P., J.H.); Escuela de Medicina, Universidad Panamericana, Mexico City, Mexico (D.P.-A.); AP-HP, Department of Genetics, Hôpital Européen Georges Pompidou, Paris, France (X.J.); and Veterans Affairs Medical Center, Portland, OR (D.H.E.)
| | - David H Ellison
- From the Molecular Physiology Unit, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, México City, Mexico (M.C.-C., M.C.-B., N.V., L.R.-V., G.G.); Department of Nephrology and Mineral Metabolism, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico (M.C.-C., E.M., M.C.-B., N.V., L.R.-V., G.G.); Division of Nephrology and Hypertension, Oregon Health and Science University, Portland (C.Z., N.P.M., S.R., X.J., C.-L.Y., D.H.E.); INSERM UMR970-Paris Cardiovascular Research Center, Paris, France (C.S., E.V.-P., X.J., J.H.); Faculty of Medicine, University Paris-Descartes, Sorbonne Paris Cité, Paris, France (C.S., E.V.-P., J.H.); Escuela de Medicina, Universidad Panamericana, Mexico City, Mexico (D.P.-A.); AP-HP, Department of Genetics, Hôpital Européen Georges Pompidou, Paris, France (X.J.); and Veterans Affairs Medical Center, Portland, OR (D.H.E.)
| | - Gerardo Gamba
- From the Molecular Physiology Unit, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, México City, Mexico (M.C.-C., M.C.-B., N.V., L.R.-V., G.G.); Department of Nephrology and Mineral Metabolism, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico (M.C.-C., E.M., M.C.-B., N.V., L.R.-V., G.G.); Division of Nephrology and Hypertension, Oregon Health and Science University, Portland (C.Z., N.P.M., S.R., X.J., C.-L.Y., D.H.E.); INSERM UMR970-Paris Cardiovascular Research Center, Paris, France (C.S., E.V.-P., X.J., J.H.); Faculty of Medicine, University Paris-Descartes, Sorbonne Paris Cité, Paris, France (C.S., E.V.-P., J.H.); Escuela de Medicina, Universidad Panamericana, Mexico City, Mexico (D.P.-A.); AP-HP, Department of Genetics, Hôpital Européen Georges Pompidou, Paris, France (X.J.); and Veterans Affairs Medical Center, Portland, OR (D.H.E.).
| | - Juliette Hadchouel
- From the Molecular Physiology Unit, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, México City, Mexico (M.C.-C., M.C.-B., N.V., L.R.-V., G.G.); Department of Nephrology and Mineral Metabolism, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico (M.C.-C., E.M., M.C.-B., N.V., L.R.-V., G.G.); Division of Nephrology and Hypertension, Oregon Health and Science University, Portland (C.Z., N.P.M., S.R., X.J., C.-L.Y., D.H.E.); INSERM UMR970-Paris Cardiovascular Research Center, Paris, France (C.S., E.V.-P., X.J., J.H.); Faculty of Medicine, University Paris-Descartes, Sorbonne Paris Cité, Paris, France (C.S., E.V.-P., J.H.); Escuela de Medicina, Universidad Panamericana, Mexico City, Mexico (D.P.-A.); AP-HP, Department of Genetics, Hôpital Européen Georges Pompidou, Paris, France (X.J.); and Veterans Affairs Medical Center, Portland, OR (D.H.E.).
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84
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Wu Y, Schellinger JN, Huang CL, Rodan AR. Hypotonicity stimulates potassium flux through the WNK-SPAK/OSR1 kinase cascade and the Ncc69 sodium-potassium-2-chloride cotransporter in the Drosophila renal tubule. J Biol Chem 2014; 289:26131-26142. [PMID: 25086033 DOI: 10.1074/jbc.m114.577767] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The ability to osmoregulate is fundamental to life. Adult Drosophila melanogaster maintain hemolymph osmolarity within a narrow range. Osmolarity modulates transepithelial ion and water flux in the Malpighian (renal) tubules of the fly, which are in direct contact with hemolymph in vivo, but the mechanisms causing increased transepithelial flux in response to hypotonicity are unknown. Fly renal tubules secrete a KCl-rich fluid. We have previously demonstrated a requirement for Ncc69, the fly sodium-potassium-2-chloride cotransporter (NKCC), in tubule K(+) secretion. Mammalian NKCCs are regulated by a kinase cascade consisting of the with-no-lysine (WNK) and Ste20-related proline/alanine-rich (SPAK)/oxidative stress response (OSR1) kinases. Here, we show that decreasing Drosophila WNK activity causes a reduction in K(+) flux. Similarly, knocking down the SPAK/OSR1 homolog fray also decreases K(+) flux. We demonstrate that a hierarchical WNK-Fray signaling cascade regulates K(+) flux through Ncc69, because (i) a constitutively active Fray mutant rescues the wnk knockdown phenotype, (ii) Fray directly phosphorylates Ncc69 in vitro, and (iii) the effect of wnk and fray knockdown is abolished in Ncc69 mutants. The stimulatory effect of hypotonicity on K(+) flux is absent in wnk, fray, or Ncc69 mutant tubules, suggesting that the Drosophila WNK-SPAK/OSR1-NKCC cascade is an essential molecular pathway for osmoregulation, through its effect on transepithelial ion flux and fluid generation by the renal tubule.
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Affiliation(s)
- Yipin Wu
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas 75390-8856
| | - Jeffrey N Schellinger
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas 75390-8856
| | - Chou-Long Huang
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas 75390-8856
| | - Aylin R Rodan
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas 75390-8856.
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85
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Eladari D, Chambrey R, Picard N, Hadchouel J. Electroneutral absorption of NaCl by the aldosterone-sensitive distal nephron: implication for normal electrolytes homeostasis and blood pressure regulation. Cell Mol Life Sci 2014; 71:2879-95. [PMID: 24556999 PMCID: PMC11113337 DOI: 10.1007/s00018-014-1585-4] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2013] [Revised: 01/28/2014] [Accepted: 02/05/2014] [Indexed: 01/10/2023]
Abstract
Sodium absorption by the distal part of the nephron, i.e., the distal convoluted tubule, the connecting tubule, and the collecting duct, plays a major role in the control of homeostasis by the kidney. In this part of the nephron, sodium transport can either be electroneutral or electrogenic. The study of electrogenic Na(+) absorption, which is mediated by the epithelial sodium channel (ENaC), has been the focus of considerable interest because of its implication in sodium, potassium, and acid-base homeostasis. However, recent studies have highlighted the crucial role played by electroneutral NaCl absorption in the regulation of the body content of sodium chloride, which in turn controls extracellular fluid volume and blood pressure. Here, we review the identification and characterization of the NaCl cotransporter (NCC), the molecule accounting for the main part of electroneutral NaCl absorption in the distal nephron, and its regulators. We also discuss recent work describing the identification of a novel "NCC-like" transport system mediated by pendrin and the sodium-driven chloride/bicarbonate exchanger (NDCBE) in the β-intercalated cells of the collecting system.
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Affiliation(s)
- Dominique Eladari
- Department of Physiology, Hopital Européen Georges Pompidou, AP-HP, 56 rue Leblanc, 75015, Paris, France,
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86
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Alessi DR, Zhang J, Khanna A, Hochdörfer T, Shang Y, Kahle KT. The WNK-SPAK/OSR1 pathway: master regulator of cation-chloride cotransporters. Sci Signal 2014; 7:re3. [PMID: 25028718 DOI: 10.1126/scisignal.2005365] [Citation(s) in RCA: 189] [Impact Index Per Article: 18.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The WNK-SPAK/OSR1 kinase complex is composed of the kinases WNK (with no lysine) and SPAK (SPS1-related proline/alanine-rich kinase) or the SPAK homolog OSR1 (oxidative stress-responsive kinase 1). The WNK family senses changes in intracellular Cl(-) concentration, extracellular osmolarity, and cell volume and transduces this information to sodium (Na(+)), potassium (K(+)), and chloride (Cl(-)) cotransporters [collectively referred to as CCCs (cation-chloride cotransporters)] and ion channels to maintain cellular and organismal homeostasis and affect cellular morphology and behavior. Several genes encoding proteins in this pathway are mutated in human disease, and the cotransporters are targets of commonly used drugs. WNKs stimulate the kinases SPAK and OSR1, which directly phosphorylate and stimulate Cl(-)-importing, Na(+)-driven CCCs or inhibit the Cl(-)-extruding, K(+)-driven CCCs. These coordinated and reciprocal actions on the CCCs are triggered by an interaction between RFXV/I motifs within the WNKs and CCCs and a conserved carboxyl-terminal docking domain in SPAK and OSR1. This interaction site represents a potentially druggable node that could be more effective than targeting the cotransporters directly. In the kidney, WNK-SPAK/OSR1 inhibition decreases epithelial NaCl reabsorption and K(+) secretion to lower blood pressure while maintaining serum K(+). In neurons, WNK-SPAK/OSR1 inhibition could facilitate Cl(-) extrusion and promote γ-aminobutyric acidergic (GABAergic) inhibition. Such drugs could have efficacy as K(+)-sparing blood pressure-lowering agents in essential hypertension, nonaddictive analgesics in neuropathic pain, and promoters of GABAergic inhibition in diseases associated with neuronal hyperactivity, such as epilepsy, spasticity, neuropathic pain, schizophrenia, and autism.
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Affiliation(s)
- Dario R Alessi
- MRC Protein Phosphorylation and Ubiquitylation Unit, College of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland
| | - Jinwei Zhang
- MRC Protein Phosphorylation and Ubiquitylation Unit, College of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland
| | - Arjun Khanna
- Department of Neurosurgery, Massachusetts General Hospital, and Harvard Medical School, Boston, MA 02115, USA
| | - Thomas Hochdörfer
- MRC Protein Phosphorylation and Ubiquitylation Unit, College of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland
| | - Yuze Shang
- Manton Center for Orphan Disease Research, Boston Children's Hospital, Boston, MA 02115, USA
| | - Kristopher T Kahle
- Department of Neurosurgery, Massachusetts General Hospital, and Harvard Medical School, Boston, MA 02115, USA. Manton Center for Orphan Disease Research, Boston Children's Hospital, Boston, MA 02115, USA.
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87
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Lagnaz D, Arroyo JP, Chávez-Canales M, Vázquez N, Rizzo F, Spirlí A, Debonneville A, Staub O, Gamba G. WNK3 abrogates the NEDD4-2-mediated inhibition of the renal Na+-Cl- cotransporter. Am J Physiol Renal Physiol 2014; 307:F275-86. [PMID: 24920754 DOI: 10.1152/ajprenal.00574.2013] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The serine/threonine kinase WNK3 and the ubiquitin-protein ligase NEDD4-2 are key regulators of the thiazide-sensitive Na+-Cl- cotransporter (NCC), WNK3 as an activator and NEDD2-4 as an inhibitor. Nedd4-2 was identified as an interacting partner of WNK3 through a glutathione-S-transferase pull-down assay using the N-terminal domain of WNK3, combined with LC-MS/MS analysis. This was validated by coimmunoprecipitation of WNK3 and NEDD4-2 expressed in HEK293 cells. Our data also revealed that the interaction between Nedd4-2 and WNK3 does not involve the PY-like motif found in WNK3. The level of WNK3 ubiquitylation did not change when NEDD4-2 was expressed in HEK293 cells. Moreover, in contrast to SGK1, WNK3 did not phosphorylate NEDD4-2 on S222 or S328. Coimmunoprecipitation assays showed that WNK3 does not regulate the interaction between NCC and NEDD4-2. Interestingly, in Xenopus laevis oocytes, WNK3 was able to recover the SGK1-resistant NEDD4-2 S222A/S328A-mediated inhibition of NCC and further activate NCC. Furthermore, elimination of the SPAK binding site in the kinase domain of WNK3 (WNK3-F242A, which lacks the capacity to bind the serine/threonine kinase SPAK) prevented the WNK3 NCC-activating effect, but not the Nedd4-2-inhibitory effect. Together, these results suggest that a novel role for WNK3 on NCC expression at the plasma membrane, an effect apparently independent of the SPAK kinase and the aldosterone-SGK1 pathway.
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Affiliation(s)
- Dagmara Lagnaz
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland; and
| | - Juan Pablo Arroyo
- Molecular Physiology Unit, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán and Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - María Chávez-Canales
- Molecular Physiology Unit, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán and Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Norma Vázquez
- Molecular Physiology Unit, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán and Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Federica Rizzo
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland; and
| | - Alessia Spirlí
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland; and
| | - Anne Debonneville
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland; and
| | - Olivier Staub
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland; and
| | - Gerardo Gamba
- Molecular Physiology Unit, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán and Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Mexico City, Mexico
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88
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Insights in cullin 3/WNK4 and its relationship to blood pressure regulation and electrolyte homeostasis. Cell Signal 2014; 26:1166-72. [DOI: 10.1016/j.cellsig.2014.01.032] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2014] [Accepted: 01/31/2014] [Indexed: 11/18/2022]
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89
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Abstract
The distal convoluted tubule is the nephron segment that lies immediately downstream of the macula densa. Although short in length, the distal convoluted tubule plays a critical role in sodium, potassium, and divalent cation homeostasis. Recent genetic and physiologic studies have greatly expanded our understanding of how the distal convoluted tubule regulates these processes at the molecular level. This article provides an update on the distal convoluted tubule, highlighting concepts and pathophysiology relevant to clinical practice.
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Affiliation(s)
- Arohan R Subramanya
- Departments of Medicine and Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania; Veterans Affairs Pittsburgh Healthcare System, Pittsburgh, Pennsylvania;
| | - David H Ellison
- Departments of Medicine and Physiology and Pharmacology, Oregon Health and Science University, Portland, Oregon; and Portland Veterans Affairs Medical Center, Portland, Oregon
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90
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Abstract
By analysing the pathogenesis of a hereditary hypertensive disease, PHAII (pseudohypoaldosteronism type II), we previously discovered that WNK (with-no-lysine kinase)–OSR1/SPAK (oxidative stress-responsive 1/Ste20-like proline/alanine-rich kinase) cascade regulates NCC (Na–Cl co-transporter) in the DCT (distal convoluted tubules) of the kidney. However, the role of WNK4 in the regulation of NCC remains controversial. To address this, we generated and analysed WNK4−/− mice. Although a moderate decrease in SPAK phosphorylation and a marked increase in WNK1 expression were evident in the kidneys of WNK4−/− mice, the amount of phosphorylated and total NCC decreased to almost undetectable levels, indicating that WNK4 is the major WNK positively regulating NCC, and that WNK1 cannot compensate for WNK4 deficiency in the DCT. Insulin- and low-potassium diet-induced NCC phosphorylation were abolished in WNK4−/− mice, establishing that both signals to NCC were mediated by WNK4. As shown previously, a high-salt diet decreases phosphorylated and total NCC in WNK4+/+ mice via AngII (angiotensin II) and aldosterone suppression. This was not ameliorated by WNK4 knock out, excluding the negative regulation of WNK4 on NCC postulated to be active in the absence of AngII stimulation. Thus, WNK4 is the major positive regulator of NCC in the kidneys. The analyses of WNK4 (with-no-lysine kinase 4) knockout mice help to end a long-standing controversy about the role of WNK4 on NCC (Na–Cl co-transporter) regulations in the kidney. WNK4 is a strong positive regulator of NCC.
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91
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Andrukhova O, Slavic S, Smorodchenko A, Zeitz U, Shalhoub V, Lanske B, Pohl EE, Erben RG. FGF23 regulates renal sodium handling and blood pressure. EMBO Mol Med 2014; 6:744-59. [PMID: 24797667 PMCID: PMC4203353 DOI: 10.1002/emmm.201303716] [Citation(s) in RCA: 239] [Impact Index Per Article: 23.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Fibroblast growth factor-23 (FGF23) is a bone-derived hormone regulating renal phosphate reabsorption and vitamin D synthesis in renal proximal tubules. Here, we show that FGF23 directly regulates the membrane abundance of the Na(+):Cl(-) co-transporter NCC in distal renal tubules by a signaling mechanism involving the FGF receptor/αKlotho complex, extracellular signal-regulated kinase 1/2 (ERK1/2), serum/glucocorticoid-regulated kinase 1 (SGK1), and with-no lysine kinase-4 (WNK4). Renal sodium (Na(+)) reabsorption and distal tubular membrane expression of NCC are reduced in mouse models of Fgf23 and αKlotho deficiency. Conversely, gain of FGF23 function by injection of wild-type mice with recombinant FGF23 or by elevated circulating levels of endogenous Fgf23 in Hyp mice increases distal tubular Na(+) uptake and membrane abundance of NCC, leading to volume expansion, hypertension, and heart hypertrophy in a αKlotho and dietary Na(+)-dependent fashion. The NCC inhibitor chlorothiazide abrogates FGF23-induced volume expansion and heart hypertrophy. Our findings suggest that FGF23 is a key regulator of renal Na(+) reabsorption and plasma volume, and may explain the association of FGF23 with cardiovascular risk in chronic kidney disease patients.
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Affiliation(s)
| | | | | | - Ute Zeitz
- University of Veterinary Medicine Vienna, Vienna, Austria
| | | | - Beate Lanske
- Harvard School of Dental Medicine, Boston, MA, USA
| | - Elena E Pohl
- University of Veterinary Medicine Vienna, Vienna, Austria
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92
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Abstract
Hereditary disorders of potassium homeostasis are an interesting group of disorders, affecting people from the newborn period to adults of all ages. The clinical presentation varies from severe hypotension at birth to uncontrolled hypertension in adults, often associated with abnormal potassium values, although many patients may have a normal serum potassium concentration despite being affected by the genetic disorder. A basic understanding of these disorders and their underlying mechanisms has significant clinical implications, especially in the few patients with subtle clinical signs and symptoms. We present a summary of these disorders, with emphasis on the clinical presentation and genetic mechanisms of these disorders.
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Affiliation(s)
- Gaurav Jain
- Division of Nephrology, University of Alabama at Birmingham, Birmingham, Alabama, USA
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93
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Fujita T. Mechanism of salt-sensitive hypertension: focus on adrenal and sympathetic nervous systems. J Am Soc Nephrol 2014; 25:1148-55. [PMID: 24578129 DOI: 10.1681/asn.2013121258] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
A central role for the kidney among the systems contributing to BP regulation and the development of hypertension has been proposed. Both the aldosterone/mineralocorticoid receptor pathway and the renal sympathetic nervous system have important roles in the regulation of renal excretory function and BP control, but the mechanisms underlying these processes have remained unclear. However, recent studies revealed the activation of two pathways in salt-sensitive hypertension. Notably, Rac1, a member of the Rho-family of small GTP binding proteins, was identified as a novel ligand-independent modulator of mineralocorticoid receptor activity. Furthermore, these studies point to crucial roles for the Rac1-mineralocorticoid receptor-NCC/ENaC and the renal β-adrenergic stimulant-glucocorticoid receptor-WNK4-NCC pathways in certain rodent models of salt-sensitive hypertension. The nuclear mineralocorticoid and glucocorticoid receptors may contribute to impaired renal excretory function and the resulting salt-sensitive hypertension by increasing sodium reabsorption at different tubular segments. This review provides an in-depth discussion of the evidence supporting these conclusions and considers the significance with regard to treating salt-sensitive hypertension and salt-induced cardiorenal injury.
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Affiliation(s)
- Toshiro Fujita
- Department of Clinical Epigenetics, Research Center for Advanced Science and Technology, The University of Tokyo, Tokyo, Japan; and CREST, Tokyo, Japan
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94
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Uchida S, Sohara E, Rai T, Sasaki S. Regulation of with-no-lysine kinase signaling by Kelch-like proteins. Biol Cell 2014; 106:45-56. [PMID: 24313290 PMCID: PMC4162998 DOI: 10.1111/boc.201300069] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2013] [Accepted: 12/03/2013] [Indexed: 12/17/2022]
Abstract
In 2001, with-no-lysine (WNK) kinases were identified as the genes responsible for the human hereditary hypertensive disease pseudohypoaldosteronism type II (PHAII). It took a further 6 years to clarify that WNK kinases participate in a signaling cascade with oxidative stress-responsive gene 1 (OSR1), Ste20-related proline-alanine-rich kinase (SPAK), and thiazide-sensitive NaCl cotransporter (NCC) in the kidney and the constitutive activation of this signaling cascade is the molecular basis of PHAII. Since this discovery, the WNK-OSR1/SPAK-NCC signaling cascade has been shown to be involved not only in PHAII but also in the regulation of blood pressure under normal and pathogenic conditions, such as hyperinsulinemia. However, the molecular mechanisms of WNK kinase regulation by dietary and hormonal factors and by PHAII-causing mutations remain poorly understood. In 2012, two additional genes responsible for PHAII, Kelch-like 3 (KLHL3) and Cullin3, were identified. At the time of their discovery, the molecular mechanisms underlying the interaction between these genes and their involvement in PHAII were unknown. Here we review the pathophysiological roles of the WNK signaling cascade clarified to date and introduce a new mechanism of WNK kinase regulation by KLHL3 and Cullin3, which provides insight on previously unknown mechanisms of WNK kinase regulation.
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Affiliation(s)
- Shinichi Uchida
- Department of Nephrology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8519, Japan
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95
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Katori M, Majima M. Renal (tissue) kallikrein-kinin system in the kidney and novel potential drugs for salt-sensitive hypertension. PROGRESS IN DRUG RESEARCH. FORTSCHRITTE DER ARZNEIMITTELFORSCHUNG. PROGRES DES RECHERCHES PHARMACEUTIQUES 2014; 69:59-109. [PMID: 25130040 DOI: 10.1007/978-3-319-06683-7_4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
A large variety of antihypertensive drugs, such as angiotensin converting enzyme inhibitors, diuretics, and others, are prescribed to hypertensive patients, with good control of the condition. In addition, all individuals are generally believed to be salt sensitive and, thus, severe restriction of salt intake is recommended to all. Nevertheless, the physiological defense mechanisms in the kidney against excess salt intake have not been well clarified. The present review article demonstrated that the renal (tissue) kallikrein-kinin system (KKS) is ideally situated within the nephrons of the kidney, where it functions to inhibit the reabsorption of NaCl through the activation of bradykinin (BK)-B2 receptors localized along the epithelial cells of the collecting ducts (CD). Kinins generated in the CD are immediately inactivated by two kidney-specific kinin-inactivating enzymes (kininases), carboxypeptidase Y-like exopeptidase (CPY), and neutral endopeptidase (NEP). Our work demonstrated that ebelactone B and poststatin are selective inhibitors of these kininases. The reduced secretion of the urinary kallikrein is linked to the development of salt-sensitive hypertension, whereas potassium ions and ATP-sensitive potassium channel blockers ameliorate salt-sensitive hypertension by accelerating the release of renal kallikrein. On the other hand, ebelactone B and poststatin prolong the life of kinins in the CD after excess salt intake, thereby leading to the augmentation of natriuresis and diuresis, and the ensuing suppression of salt-sensitive hypertension. In conclusion, accelerators of the renal kallikrein release and selective renal kininase inhibitors are both novel types of antihypertensive agents that may be useful for treatment of salt-sensitive hypertension.
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96
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Matsuki K, Hathaway CK, Lawrence MG, Smithies O, Kakoki M. The role of transforming growth factor β1 in the regulation of blood pressure. Curr Hypertens Rev 2014; 10:223-38. [PMID: 25801626 PMCID: PMC4842018 DOI: 10.2174/157340211004150319123313] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2014] [Revised: 02/19/2015] [Accepted: 02/23/2015] [Indexed: 01/21/2023]
Abstract
Although human association studies suggest a link between polymorphisms in the gene encoding transforming growth factor (TGF) β1 and differing blood pressure levels, a causative mechanism for this correlation remains elusive. Recently we have generated a series of mice with graded expression of TGFβ1, ranging from approximately 10% to 300% compared to normal. We have found that blood pressure and plasma volume are negatively regulated by TGFβ1. Of note, the 10% hypomorph exhibits primary aldosteronism and markedly impaired urinary excretion of water and electrolytes. We here review previous literature highlighting the importance of TGFβ signaling as a natriuretic system, which we postulate is a causative mechanism explaining how polymorphisms in TGFβ1 could influence blood pressure levels.
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Affiliation(s)
| | | | | | | | - Masao Kakoki
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, CB #7525, 701 Brinkhous-Bullitt Building, Chapel Hill, NC 27599-7525, USA.
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97
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Moes AD, van der Lubbe N, Zietse R, Loffing J, Hoorn EJ. The sodium chloride cotransporter SLC12A3: new roles in sodium, potassium, and blood pressure regulation. Pflugers Arch 2013; 466:107-18. [PMID: 24310820 DOI: 10.1007/s00424-013-1407-9] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2013] [Revised: 11/19/2013] [Accepted: 11/20/2013] [Indexed: 12/14/2022]
Abstract
SLC12A3 encodes the thiazide-sensitive sodium chloride cotransporter (NCC), which is primarily expressed in the kidney, but also in intestine and bone. In the kidney, NCC is located in the apical plasma membrane of epithelial cells in the distal convoluted tubule. Although NCC reabsorbs only 5 to 10% of filtered sodium, it is important for the fine-tuning of renal sodium excretion in response to various hormonal and non-hormonal stimuli. Several new roles for NCC in the regulation of sodium, potassium, and blood pressure have been unraveled recently. For example, the recent discoveries that NCC is activated by angiotensin II but inhibited by dietary potassium shed light on how the kidney handles sodium during hypovolemia (high angiotensin II) and hyperkalemia. The additive effect of angiotensin II and aldosterone maximizes sodium reabsorption during hypovolemia, whereas the inhibitory effect of potassium on NCC increases delivery of sodium to the potassium-secreting portion of the nephron. In addition, great steps have been made in unraveling the molecular machinery that controls NCC. This complex network consists of kinases and ubiquitinases, including WNKs, SGK1, SPAK, Nedd4-2, Cullin-3, and Kelch-like 3. The pathophysiological significance of this network is illustrated by the fact that modification of each individual protein in the network changes NCC activity and results in salt-dependent hypotension or hypertension. This review aims to summarize these new insights in an integrated manner while identifying unanswered questions.
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Affiliation(s)
- Arthur D Moes
- Department of Internal Medicine, Erasmus Medical Center, PO Box 2040, Room H-438, 3000 CA, Rotterdam, The Netherlands
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Hong JH, Park S, Shcheynikov N, Muallem S. Mechanism and synergism in epithelial fluid and electrolyte secretion. Pflugers Arch 2013; 466:1487-99. [PMID: 24240699 DOI: 10.1007/s00424-013-1390-1] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2013] [Revised: 10/16/2013] [Accepted: 10/17/2013] [Indexed: 01/04/2023]
Abstract
A central function of epithelia is the control of the volume and electrolyte composition of bodily fluids through vectorial transport of electrolytes and the obligatory H2O. In exocrine glands, fluid and electrolyte secretion is carried out by both acinar and duct cells, with the portion of fluid secreted by each cell type varying among glands. All acinar cells secrete isotonic, plasma-like fluid, while the duct determines the final electrolyte composition of the fluid by absorbing most of the Cl(-) and secreting HCO3 (-). The key transporters mediating acinar fluid and electrolyte secretion are the basolateral Na(+)/K(+) /2Cl(-) cotransporter, the luminal Ca(2+)-activated Cl(-) channel ANO1 and basolateral and luminal Ca(2+)-activated K(+) channels. Ductal fluid and HCO3 (-) secretion are mediated by the basolateral membrane Na(+)-HCO3 (-) cotransporter NBCe1-B and the luminal membrane Cl(-)/HCO3 (-) exchanger slc26a6 and the Cl(-) channel CFTR. The function of the transporters is regulated by multiple inputs, which in the duct include major regulation by the WNK/SPAK pathway that inhibit secretion and the IRBIT/PP1 pathway that antagonize the effects of the WNK/SPAK pathway to both stimulate and coordinate the secretion. The function of these regulatory pathways in secretory glands acinar cells is yet to be examined. An important concept in biology is synergism among signaling pathways to generate the final physiological response that ensures regulation with high fidelity and guards against cell toxicity. While synergism is observed in all epithelial functions, the molecular mechanism mediating the synergism is not known. Recent work reveals a central role for IRBIT as a third messenger that integrates and synergizes the function of the Ca(2+) and cAMP signaling pathways in activation of epithelial fluid and electrolyte secretion. These concepts are discussed in this review using secretion by the pancreatic and salivary gland ducts as model systems.
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Affiliation(s)
- Jeong Hee Hong
- Epithelial Signaling and Transport Section, Molecular Physiology and Therapeutics Branch, National Institute of Dental and Craniofacial Research, National Institute of Health, Bethesda, MD, 20892, USA
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Picard N, Trompf K, Yang CL, Miller RL, Carrel M, Loffing-Cueni D, Fenton RA, Ellison DH, Loffing J. Protein phosphatase 1 inhibitor-1 deficiency reduces phosphorylation of renal NaCl cotransporter and causes arterial hypotension. J Am Soc Nephrol 2013; 25:511-22. [PMID: 24231659 DOI: 10.1681/asn.2012121202] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The thiazide-sensitive NaCl cotransporter (NCC) of the renal distal convoluted tubule (DCT) controls ion homeostasis and arterial BP. Loss-of-function mutations of NCC cause renal salt wasting with arterial hypotension (Gitelman syndrome). Conversely, mutations in the NCC-regulating WNK kinases or kelch-like 3 protein cause familial hyperkalemic hypertension. Here, we performed automated sorting of mouse DCTs and microarray analysis for comprehensive identification of novel DCT-enriched gene products, which may potentially regulate DCT and NCC function. This approach identified protein phosphatase 1 inhibitor-1 (I-1) as a DCT-enriched transcript, and immunohistochemistry revealed I-1 expression in mouse and human DCTs and thick ascending limbs. In heterologous expression systems, coexpression of NCC with I-1 increased thiazide-dependent Na(+) uptake, whereas RNAi-mediated knockdown of endogenous I-1 reduced NCC phosphorylation. Likewise, levels of phosphorylated NCC decreased by approximately 50% in I-1 (I-1(-/-)) knockout mice without changes in total NCC expression. The abundance and phosphorylation of other renal sodium-transporting proteins, including NaPi-IIa, NKCC2, and ENaC, did not change, although the abundance of pendrin increased in these mice. The abundance, phosphorylation, and subcellular localization of SPAK were similar in wild-type (WT) and I-1(-/-) mice. Compared with WT mice, I-1(-/-) mice exhibited significantly lower arterial BP but did not display other metabolic features of NCC dysregulation. Thus, I-1 is a DCT-enriched gene product that controls arterial BP, possibly through regulation of NCC activity.
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Affiliation(s)
- Nicolas Picard
- Institute of Anatomy, University of Zurich, Zurich, Switzerland
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Christensen EI, Wagner CA, Kaissling B. Uriniferous tubule: structural and functional organization. Compr Physiol 2013; 2:805-61. [PMID: 23961562 DOI: 10.1002/cphy.c100073] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The uriniferous tubule is divided into the proximal tubule, the intermediate (thin) tubule, the distal tubule and the collecting duct. The present chapter is based on the chapters by Maunsbach and Christensen on the proximal tubule, and by Kaissling and Kriz on the distal tubule and collecting duct in the 1992 edition of the Handbook of Physiology, Renal Physiology. It describes the fine structure (light and electron microscopy) of the entire mammalian uriniferous tubule, mainly in rats, mice, and rabbits. The structural data are complemented by recent data on the location of the major transport- and transport-regulating proteins, revealed by morphological means(immunohistochemistry, immunofluorescence, and/or mRNA in situ hybridization). The structural differences along the uriniferous tubule strictly coincide with the distribution of the major luminal and basolateral transport proteins and receptors and both together provide the basis for the subdivision of the uriniferous tubule into functional subunits. Data on structural adaptation to defined functional changes in vivo and to genetical alterations of specified proteins involved in transepithelial transport importantly deepen our comprehension of the correlation of structure and function in the kidney, of the role of each segment or cell type in the overall renal function,and our understanding of renal pathophysiology.
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