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Ying S, Guo Q, Zhang C. KLHL3-dependent WNK4 degradation affected by potassium through the neddylation and autophagy pathway. BMC Nephrol 2023; 24:217. [PMID: 37481568 PMCID: PMC10362690 DOI: 10.1186/s12882-023-03257-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Accepted: 06/29/2023] [Indexed: 07/24/2023] Open
Abstract
BACKGROUND Studies reported that kelch-like protein 3 (KLHL3)-Cullin3(CUL3) E3 ligase ubiquitinated with-no-lysine kinase 4 (WNK4). Impaired WNK4 ubiquitination plays a key role in Familial hyperkalemic hypertension (FHHt, also called pseudohypoaldosteronism type II) which results from overaction of thiazide-sensitive sodium chloride cotransport (NCC). In addition, researchers have also found that dietary potassium deficiency activates NCC along the renal distal convoluted tubule (DCT). However, the underlying mechanism remains unclear about the relationship between potassium and WNK4. METHODS In the present study, we conducted in vitro and in vivo experiments to confirm that KLHL3-dependent WNK4 degradation is affected by potassium through the neddylation and autophagy pathway. In vitro, the WNK4 and KLHL3 plasmids were cotransfected into HEK293 cell lines by lipofectamine 2000, and then incubated with different potassium concentrations (1mmol/L and 10mmol/L) for 24 h, and further treated with MLN4924 or the autophagy inhibitor or both of MLN4924 and the autophagy inhibitor for another 24 h respectively. In vivo, we created mice that were fed with low or high potassium diets and then were injected MLN4924 in the experimental groups. The expression of WNK4, pWNK4, KLHL3, NEDD8, LC3 ,and P62 was detected by western blotting in vitro and vivo experiments. RESULTS We found that the abundance and phosphorylation of WNK4 increase when neddylation is inhibited both in vitro and vivo. Furthermore, the abundance of pWNK4, WNK4, NEDD8, and KLHL3 was increased in the low potassium (LK) group. Inhibiting autophagy can ameliorate the effect of potassium on the abundance and activity of WNK4 to some extent. CONCLUSION These findings suggest a complex regulation of potassium in the degradation of WNK4. Low potassium can activate WNK4, which may be related to neddylation and autophagy, but the mechanism needs to be further studied.
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Affiliation(s)
- Siqi Ying
- Department of Nephrology, Jing'an District Center Hospital of Shanghai, Fudan University, Shanghai, 200040, China
| | - Qin Guo
- Department of Nephrology, Xin Hua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai Shi, China
| | - Chong Zhang
- Department of Nephrology, Xin Hua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai Shi, China.
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2
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Ferreira G, Santander A, Cardozo R, Chavarría L, Domínguez L, Mujica N, Benítez M, Sastre S, Sobrevia L, Nicolson GL. Nutrigenomics of inward rectifier potassium channels. Biochim Biophys Acta Mol Basis Dis 2023:166803. [PMID: 37406972 DOI: 10.1016/j.bbadis.2023.166803] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Revised: 06/27/2023] [Accepted: 06/30/2023] [Indexed: 07/07/2023]
Abstract
Inwardly rectifying potassium (Kir) channels play a key role in maintaining the resting membrane potential and supporting potassium homeostasis. There are many variants of Kir channels, which are usually tetramers in which the main subunit has two trans-membrane helices attached to two N- and C-terminal cytoplasmic tails with a pore-forming loop in between that contains the selectivity filter. These channels have domains that are strongly modulated by molecules present in nutrients found in different diets, such as phosphoinositols, polyamines and Mg2+. These molecules can impact these channels directly or indirectly, either allosterically by modulation of enzymes or via the regulation of channel expression. A particular type of these channels is coupled to cell metabolism and inhibited by ATP (KATP channels, essential for insulin release and for the pathogenesis of metabolic diseases like diabetes mellitus). Genomic changes in Kir channels have a significant impact on metabolism, such as conditioning the nutrients and electrolytes that an individual can take. Thus, the nutrigenomics of ion channels is an important emerging field in which we are attempting to understand how nutrients and diets can affect the activity and expression of ion channels and how genomic changes in such channels may be the basis for pathological conditions that limit nutrition and electrolyte intake. In this contribution we briefly review Kir channels, discuss their nutrigenomics, characterize how different components in the diet affect their function and expression, and suggest how their genomic changes lead to pathological phenotypes that affect diet and electrolyte intake.
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Affiliation(s)
- Gonzalo Ferreira
- Laboratory of Ion Channels, Biological Membranes and Cell Signaling, Dept. of Biophysics, Facultad de Medicina, CP 11800, Universidad de la Republica, Montevideo, Uruguay.
| | - Axel Santander
- Laboratory of Ion Channels, Biological Membranes and Cell Signaling, Dept. of Biophysics, Facultad de Medicina, CP 11800, Universidad de la Republica, Montevideo, Uruguay
| | - Romina Cardozo
- Laboratory of Ion Channels, Biological Membranes and Cell Signaling, Dept. of Biophysics, Facultad de Medicina, CP 11800, Universidad de la Republica, Montevideo, Uruguay
| | - Luisina Chavarría
- Laboratory of Ion Channels, Biological Membranes and Cell Signaling, Dept. of Biophysics, Facultad de Medicina, CP 11800, Universidad de la Republica, Montevideo, Uruguay
| | - Lucía Domínguez
- Laboratory of Ion Channels, Biological Membranes and Cell Signaling, Dept. of Biophysics, Facultad de Medicina, CP 11800, Universidad de la Republica, Montevideo, Uruguay
| | - Nicolás Mujica
- Laboratory of Ion Channels, Biological Membranes and Cell Signaling, Dept. of Biophysics, Facultad de Medicina, CP 11800, Universidad de la Republica, Montevideo, Uruguay
| | - Milagros Benítez
- Laboratory of Ion Channels, Biological Membranes and Cell Signaling, Dept. of Biophysics, Facultad de Medicina, CP 11800, Universidad de la Republica, Montevideo, Uruguay
| | - Santiago Sastre
- Laboratory of Ion Channels, Biological Membranes and Cell Signaling, Dept. of Biophysics, Facultad de Medicina, CP 11800, Universidad de la Republica, Montevideo, Uruguay; Centro de Investigaciones Biomédicas (CEINBIO), Universidad de la República, Montevideo CP 11800, Uruguay
| | - Luis Sobrevia
- Cellular and Molecular Physiology Laboratory (CMPL), Department of Obstetrics, Division of Obstetrics and Gynaecology, School of Medicine, Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago 8330024, Chile; Department of Physiology, Faculty of Pharmacy, Universidad de Sevilla, Seville E-41012, Spain; Medical School (Faculty of Medicine), Sao Paulo State University (UNESP), Brazil; University of Queensland, Centre for Clinical Research (UQCCR), Faculty of Medicine and Biomedical Sciences, University of Queensland, Herston, 4029, Queensland, Australia; Tecnologico de Monterrey, Eutra, The Institute for Obesity Research (IOR), School of Medicine and Health Sciences, Monterrey, Nuevo León, Mexico
| | - Garth L Nicolson
- Department of Molecular Pathology, The Institute for Molecular Medicine, Huntington Beach, CA, USA
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Gao ZX, Wei QC, Shu TT, Li ST, Zhou R, Li MY, Mao ZH, Liu DW, Liu ZS, Wu P. Kir4.1 deletion prevents salt-sensitive hypertension in early streptozotocin-induced diabetic mice via Na + -Cl - cotransporter in the distal convoluted tubule. J Hypertens 2023; 41:958-970. [PMID: 37016934 DOI: 10.1097/hjh.0000000000003419] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/06/2023]
Abstract
OBJECTIVES Functional impairment of renal sodium handling and blood pressure (BP) homeostasis is an early characteristic manifestation of type 1 diabetes. However, the underlying mechanisms remain unclear. METHODS Metabolic cages, radio-telemetry, immunoblotting, and electrophysiology were utilized to examine effects of high salt (8% NaCl, HS) intake on Na + /K + balance, BP, Na + -Cl - cotransporter (NCC) function, and basolateral K + channel activity in the distal convoluted tubule (DCT) under diabetic conditions. RESULTS Improper Na + balance, hypernatremia, and a mild but significant increase in BP were found in streptozotocin (STZ)-induced diabetic mice in response to HS intake for 7 days. Compared to the vehicle, STZ mice showed increased Kir4.1 expression and activity in the DCT, a more negative membrane potential, higher NCC abundance, and enhanced hydrochlorothiazide-induced natriuretic effect. However, HS had no significant effect on basolateral Kir4.1 expression/activity and DCT membrane potential, or NCC activity under diabetic conditions, despite a downregulation in phosphorylated NCC abundance. In contrast, HS significantly downregulated the expression of Na + -H + exchanger 3 (NHE3) and cleaved epithelial sodium channel-γ in STZ mice, despite an increase in NHE3 abundance after STZ treatment. Kir4.1 deletion largely abolished STZ-induced upregulation of NCC expression and prevented BP elevation during HS intake. Interestingly, HS causes severe hypokalemia in STZ-treated kidney-specific Kir4.1 knockout (Ks-Kir4.1 KO) mice and lead to death within a few days, which could be attributed to a higher circulating aldosterone level. CONCLUSIONS We concluded that Kir4.1 is required for upregulating NCC activity and may be essential for developing salt-sensitive hypertension in early STZ-induced diabetes.
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Affiliation(s)
- Zhong-Xiuzi Gao
- Traditional Chinese Medicine Integrated Department of Nephrology, The First Affiliated Hospital of Zhengzhou University
- Institute of Nephrology, Zhengzhou University
- Henan Province Clinical Research Center for Kidney Disease
- Key Laboratory of Precision Diagnosis and Treatment for Chronic Kidney Disease in Henan Province, Zhengzhou, China
| | - Qi-Chao Wei
- Traditional Chinese Medicine Integrated Department of Nephrology, The First Affiliated Hospital of Zhengzhou University
- Institute of Nephrology, Zhengzhou University
- Henan Province Clinical Research Center for Kidney Disease
- Key Laboratory of Precision Diagnosis and Treatment for Chronic Kidney Disease in Henan Province, Zhengzhou, China
| | - Ting-Ting Shu
- Traditional Chinese Medicine Integrated Department of Nephrology, The First Affiliated Hospital of Zhengzhou University
- Institute of Nephrology, Zhengzhou University
- Henan Province Clinical Research Center for Kidney Disease
- Key Laboratory of Precision Diagnosis and Treatment for Chronic Kidney Disease in Henan Province, Zhengzhou, China
| | - Shu-Ting Li
- Traditional Chinese Medicine Integrated Department of Nephrology, The First Affiliated Hospital of Zhengzhou University
- Institute of Nephrology, Zhengzhou University
- Henan Province Clinical Research Center for Kidney Disease
- Key Laboratory of Precision Diagnosis and Treatment for Chronic Kidney Disease in Henan Province, Zhengzhou, China
| | - Rui Zhou
- Traditional Chinese Medicine Integrated Department of Nephrology, The First Affiliated Hospital of Zhengzhou University
- Institute of Nephrology, Zhengzhou University
- Henan Province Clinical Research Center for Kidney Disease
- Key Laboratory of Precision Diagnosis and Treatment for Chronic Kidney Disease in Henan Province, Zhengzhou, China
| | - Ming-Yan Li
- Traditional Chinese Medicine Integrated Department of Nephrology, The First Affiliated Hospital of Zhengzhou University
- Institute of Nephrology, Zhengzhou University
- Henan Province Clinical Research Center for Kidney Disease
- Key Laboratory of Precision Diagnosis and Treatment for Chronic Kidney Disease in Henan Province, Zhengzhou, China
| | - Zi-Hui Mao
- Traditional Chinese Medicine Integrated Department of Nephrology, The First Affiliated Hospital of Zhengzhou University
- Institute of Nephrology, Zhengzhou University
- Henan Province Clinical Research Center for Kidney Disease
- Key Laboratory of Precision Diagnosis and Treatment for Chronic Kidney Disease in Henan Province, Zhengzhou, China
| | - Dong-Wei Liu
- Traditional Chinese Medicine Integrated Department of Nephrology, The First Affiliated Hospital of Zhengzhou University
- Institute of Nephrology, Zhengzhou University
- Henan Province Clinical Research Center for Kidney Disease
- Key Laboratory of Precision Diagnosis and Treatment for Chronic Kidney Disease in Henan Province, Zhengzhou, China
| | - Zhang-Suo Liu
- Traditional Chinese Medicine Integrated Department of Nephrology, The First Affiliated Hospital of Zhengzhou University
- Institute of Nephrology, Zhengzhou University
- Henan Province Clinical Research Center for Kidney Disease
- Key Laboratory of Precision Diagnosis and Treatment for Chronic Kidney Disease in Henan Province, Zhengzhou, China
| | - Peng Wu
- Traditional Chinese Medicine Integrated Department of Nephrology, The First Affiliated Hospital of Zhengzhou University
- Institute of Nephrology, Zhengzhou University
- Henan Province Clinical Research Center for Kidney Disease
- Key Laboratory of Precision Diagnosis and Treatment for Chronic Kidney Disease in Henan Province, Zhengzhou, China
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4
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Johnston JG, Welch AK, Cain BD, Sayeski PP, Gumz ML, Wingo CS. Aldosterone: Renal Action and Physiological Effects. Compr Physiol 2023; 13:4409-4491. [PMID: 36994769 DOI: 10.1002/cphy.c190043] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/31/2023]
Abstract
Aldosterone exerts profound effects on renal and cardiovascular physiology. In the kidney, aldosterone acts to preserve electrolyte and acid-base balance in response to changes in dietary sodium (Na+ ) or potassium (K+ ) intake. These physiological actions, principally through activation of mineralocorticoid receptors (MRs), have important effects particularly in patients with renal and cardiovascular disease as demonstrated by multiple clinical trials. Multiple factors, be they genetic, humoral, dietary, or otherwise, can play a role in influencing the rate of aldosterone synthesis and secretion from the adrenal cortex. Normally, aldosterone secretion and action respond to dietary Na+ intake. In the kidney, the distal nephron and collecting duct are the main targets of aldosterone and MR action, which stimulates Na+ absorption in part via the epithelial Na+ channel (ENaC), the principal channel responsible for the fine-tuning of Na+ balance. Our understanding of the regulatory factors that allow aldosterone, via multiple signaling pathways, to function properly clearly implicates this hormone as central to many pathophysiological effects that become dysfunctional in disease states. Numerous pathologies that affect blood pressure (BP), electrolyte balance, and overall cardiovascular health are due to abnormal secretion of aldosterone, mutations in MR, ENaC, or effectors and modulators of their action. Study of the mechanisms of these pathologies has allowed researchers and clinicians to create novel dietary and pharmacological targets to improve human health. This article covers the regulation of aldosterone synthesis and secretion, receptors, effector molecules, and signaling pathways that modulate its action in the kidney. We also consider the role of aldosterone in disease and the benefit of mineralocorticoid antagonists. © 2023 American Physiological Society. Compr Physiol 13:4409-4491, 2023.
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Affiliation(s)
- Jermaine G Johnston
- Division of Nephrology, Hypertension and Renal Transplantation, Department of Medicine, University of Florida, Gainesville, Florida, USA
- Department of Physiology and Functional Genomics, University of Florida, Gainesville, Florida, USA
- Nephrology Section, Veteran Administration Medical Center, North Florida/South Georgia Malcom Randall Department of Veterans Affairs Medical Center, Gainesville, Florida, USA
| | - Amanda K Welch
- Division of Nephrology, Hypertension and Renal Transplantation, Department of Medicine, University of Florida, Gainesville, Florida, USA
- Nephrology Section, Veteran Administration Medical Center, North Florida/South Georgia Malcom Randall Department of Veterans Affairs Medical Center, Gainesville, Florida, USA
| | - Brian D Cain
- Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, Florida, USA
| | - Peter P Sayeski
- Department of Physiology and Functional Genomics, University of Florida, Gainesville, Florida, USA
| | - Michelle L Gumz
- Division of Nephrology, Hypertension and Renal Transplantation, Department of Medicine, University of Florida, Gainesville, Florida, USA
- Department of Physiology and Functional Genomics, University of Florida, Gainesville, Florida, USA
- Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, Florida, USA
- Nephrology Section, Veteran Administration Medical Center, North Florida/South Georgia Malcom Randall Department of Veterans Affairs Medical Center, Gainesville, Florida, USA
| | - Charles S Wingo
- Division of Nephrology, Hypertension and Renal Transplantation, Department of Medicine, University of Florida, Gainesville, Florida, USA
- Department of Physiology and Functional Genomics, University of Florida, Gainesville, Florida, USA
- Nephrology Section, Veteran Administration Medical Center, North Florida/South Georgia Malcom Randall Department of Veterans Affairs Medical Center, Gainesville, Florida, USA
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5
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Gallafassi E, Bezerra M, Rebouças N. Control of sodium and potassium homeostasis by renal distal convoluted tubules. Braz J Med Biol Res 2023; 56:e12392. [PMID: 36790288 PMCID: PMC9925193 DOI: 10.1590/1414-431x2023e12392] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Accepted: 12/17/2022] [Indexed: 02/12/2023] Open
Abstract
Distal convoluted tubules (DCT), which contain the Na-Cl cotransporter (NCC) inhibited by thiazide diuretics, undergo complex modulation to preserve Na+ and K+ homeostasis. The lysine kinases 1 and 4 (WNK1 and WNK4), identified as hyperactive in the hereditary disease pseudohypoaldosteronism type 2, are responsible for activation of NCC and consequent hypokalemia and hypertension. WNK4, highly expressed in DCT, activates the SPAK/OSR1 kinases, which phosphorylate NCC and other regulatory proteins and transporters in the distal nephron. WNK4 works as a chloride sensor through a Cl- binding site, which acts as an on/off switch at this kinase in response to changes of basolateral membrane electrical potential, the driving force of cellular Cl- efflux. High intracellular Cl- in hyperkalemia decreases NCC phosphorylation and low intracellular Cl- in hypokalemia increases NCC phosphorylation and activity, which makes plasma K+ concentration a central modulator of NCC and of K+ secretion. The WNK4 phosphorylation by cSrc or SGK1, activated by angiotensin II or aldosterone, respectively, is another relevant mechanism of NCC, ENaC, and ROMK modulation in states such as volume reduction, hyperkalemia, and hypokalemia. Loss of NCC function induces upregulation of electroneutral NaCl reabsorption by type B intercalated cells through the combined activity of pendrin and NDCBE, as demonstrated in double knockout mice (KO) animal models, Ncc/pendrin or Ncc/NDCBE. The analysis of ks-Nedd-4-2 KO animal models introduced the modulation of NEDD4-2 by intracellular Mg2+ activity as an important regulator of NCC, explaining the thiazide-induced persistent hypokalemia.
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Affiliation(s)
- E.A. Gallafassi
- Faculdade Israelita de Ciências da Saúde Albert Einstein, São Paulo, SP, Brasil
| | - M.B. Bezerra
- Faculdade Israelita de Ciências da Saúde Albert Einstein, São Paulo, SP, Brasil
| | - N.A. Rebouças
- Faculdade Israelita de Ciências da Saúde Albert Einstein, São Paulo, SP, Brasil
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6
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Gao ZX, Zhou R, Li MY, Li ST, Mao ZH, Shu TT, Liu DW, Liu ZS, Wu P. Activation of Kir4.1/Kir5.1 contributes to the cyclosporin A-induced stimulation of the renal NaCl cotransporter and hyperkalemic hypertension. Acta Physiol (Oxf) 2023; 238:e13948. [PMID: 36764674 DOI: 10.1111/apha.13948] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Revised: 01/16/2023] [Accepted: 02/07/2023] [Indexed: 02/12/2023]
Abstract
AIM Cyclosporin A (CsA) is a widely used immunosuppressive drug that causes hypertension and hyperkalemia. Moreover, CsA-induced stimulation of the thiazide-sensitive NaCl cotransporter (NCC) in the kidney has been shown to be responsible for the development of hyperkalemic hypertension. In this study, we tested whether CsA induces the activation of NCC by stimulating the basolateral Kir4.1/Kir5.1 channel in the distal convoluted tubule (DCT). METHODS Electrophysiology, immunoblotting, metabolic cages, and radio-telemetry methods were used to examine the effects of CsA on Kir4.1/Kir5.1 activity in the DCT, NCC function, and blood pressure in wild-type (WT) and kidney-specific Kir4.1 knockout (KS-Kir4.1 KO) mice. RESULTS The single-channel patch clamp experiment demonstrated that CsA stimulated the basolateral 40 pS K+ channel in the DCT. Whole-cell recording showed that short-term CsA administration (2 h) not only increased DCT K+ currents but also shifted the K+ current (IK ) reversal potential to the negative range (hyperpolarization). Furthermore, CsA administration increased phosphorylated NCC (pNCC) levels and inhibited renal Na+ and K+ excretions in WT mice but not in KS-Kir4.1 KO mice, suggesting that Kir4.1 is required to mediate CsA effects on NCC function. Finally, long-term CsA infusion (14 days) increased blood pressure, plasma K+ concentration, and total NCC or pNCC abundance in WT mice, but these effects were blunted in KS-Kir4.1 KO mice. CONCLUSION We conclude that CsA stimulates basolateral K+ channel activity in the DCT and that Kir4.1 is essential for CsA-induced NCC activation and hyperkalemic hypertension.
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Affiliation(s)
- Zhong-Xiuzi Gao
- Traditional Chinese Medicine Integrated Department of Nephrology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China.,Institute of Nephrology, Zhengzhou University, Zhengzhou, China.,Henan Province Research Center for Kidney Disease, Zhengzhou, China.,Key Laboratory of Precision Diagnosis and Treatment for Chronic Kidney Disease in Henan Province, Zhengzhou, China
| | - Rui Zhou
- Traditional Chinese Medicine Integrated Department of Nephrology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China.,Institute of Nephrology, Zhengzhou University, Zhengzhou, China.,Henan Province Research Center for Kidney Disease, Zhengzhou, China.,Key Laboratory of Precision Diagnosis and Treatment for Chronic Kidney Disease in Henan Province, Zhengzhou, China
| | - Ming-Yan Li
- Traditional Chinese Medicine Integrated Department of Nephrology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China.,Institute of Nephrology, Zhengzhou University, Zhengzhou, China.,Henan Province Research Center for Kidney Disease, Zhengzhou, China.,Key Laboratory of Precision Diagnosis and Treatment for Chronic Kidney Disease in Henan Province, Zhengzhou, China
| | - Shu-Ting Li
- Traditional Chinese Medicine Integrated Department of Nephrology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China.,Institute of Nephrology, Zhengzhou University, Zhengzhou, China.,Henan Province Research Center for Kidney Disease, Zhengzhou, China.,Key Laboratory of Precision Diagnosis and Treatment for Chronic Kidney Disease in Henan Province, Zhengzhou, China
| | - Zi-Hui Mao
- Traditional Chinese Medicine Integrated Department of Nephrology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China.,Institute of Nephrology, Zhengzhou University, Zhengzhou, China.,Henan Province Research Center for Kidney Disease, Zhengzhou, China.,Key Laboratory of Precision Diagnosis and Treatment for Chronic Kidney Disease in Henan Province, Zhengzhou, China
| | - Ting-Ting Shu
- Traditional Chinese Medicine Integrated Department of Nephrology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China.,Institute of Nephrology, Zhengzhou University, Zhengzhou, China.,Henan Province Research Center for Kidney Disease, Zhengzhou, China.,Key Laboratory of Precision Diagnosis and Treatment for Chronic Kidney Disease in Henan Province, Zhengzhou, China
| | - Dong-Wei Liu
- Traditional Chinese Medicine Integrated Department of Nephrology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China.,Institute of Nephrology, Zhengzhou University, Zhengzhou, China.,Henan Province Research Center for Kidney Disease, Zhengzhou, China.,Key Laboratory of Precision Diagnosis and Treatment for Chronic Kidney Disease in Henan Province, Zhengzhou, China
| | - Zhang-Suo Liu
- Traditional Chinese Medicine Integrated Department of Nephrology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China.,Institute of Nephrology, Zhengzhou University, Zhengzhou, China.,Henan Province Research Center for Kidney Disease, Zhengzhou, China.,Key Laboratory of Precision Diagnosis and Treatment for Chronic Kidney Disease in Henan Province, Zhengzhou, China
| | - Peng Wu
- Traditional Chinese Medicine Integrated Department of Nephrology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China.,Institute of Nephrology, Zhengzhou University, Zhengzhou, China.,Henan Province Research Center for Kidney Disease, Zhengzhou, China.,Key Laboratory of Precision Diagnosis and Treatment for Chronic Kidney Disease in Henan Province, Zhengzhou, China
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7
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Viering DH, Hureaux M, Neveling K, Latta F, Kwint M, Blanchard A, Konrad M, Bindels RJ, Schlingmann KP, Vargas-Poussou R, de Baaij JH. Long-Read Sequencing Identifies Novel Pathogenic Intronic Variants in Gitelman Syndrome. J Am Soc Nephrol 2023; 34:333-345. [PMID: 36302598 PMCID: PMC10103101 DOI: 10.1681/asn.2022050627] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Accepted: 10/17/2022] [Indexed: 02/04/2023] Open
Abstract
BACKGROUND Gitelman syndrome is a salt-losing tubulopathy characterized by hypokalemic alkalosis and hypomagnesemia. It is caused by homozygous recessive or compound heterozygous pathogenic variants in SLC12A3 , which encodes the Na + -Cl - cotransporter (NCC). In up to 10% of patients with Gitelman syndrome, current genetic techniques detect only one specific pathogenic variant. This study aimed to identify a second pathogenic variant in introns, splice sites, or promoters to increase the diagnostic yield. METHODS Long-read sequencing of SLC12A3 was performed in 67 DNA samples from individuals with suspected Gitelman syndrome in whom a single likely pathogenic or pathogenic variant was previously detected. In addition, we sequenced DNA samples from 28 individuals with one variant of uncertain significance or no candidate variant. Midigene splice assays assessed the pathogenicity of novel intronic variants. RESULTS A second likely pathogenic/pathogenic variant was identified in 45 (67%) patients. Those with two likely pathogenic/pathogenic variants had a more severe electrolyte phenotype than other patients. Of the 45 patients, 16 had intronic variants outside of canonic splice sites (nine variants, mostly deep intronic, six novel), whereas 29 patients had an exonic variant or canonic splice site variant. Midigene splice assays of the previously known c.1670-191C>T variant and intronic candidate variants demonstrated aberrant splicing patterns. CONCLUSION Intronic pathogenic variants explain an important part of the missing heritability in Gitelman syndrome. Long-read sequencing should be considered in diagnostic workflows for Gitelman syndrome.
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Affiliation(s)
- Daan H.H.M. Viering
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Marguerite Hureaux
- Reference Center for Hereditary Kidney and Childhood Diseases (Maladies Rénales Héréditaires de l’Enfant et de l’Adulte, MARHEA), Paris, France
- Department of Genetics, Hôpital Européen Georges-Pompidou, Assistance Publique Hôpitaux de Paris, Paris, France
- Paris CardioVascular Research Center, Institut National de la Santé et de Recherche Médicale (INSERM) U970, Paris City University, Paris, France
| | - Kornelia Neveling
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Femke Latta
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Michael Kwint
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Anne Blanchard
- Reference Center for Hereditary Kidney and Childhood Diseases (Maladies Rénales Héréditaires de l’Enfant et de l’Adulte, MARHEA), Paris, France
- Clinical Investigations Center, Hôpital Européen Georges-Pompidou, Assistance Publique Hôpitaux de Paris, Paris, France
- Centre de Recherche des Cordeliers, Sorbonne Université, INSERM, University of Paris, Centre National de la Recherche Scientifique (CNRS), Paris, France
| | - Martin Konrad
- Department of General Pediatrics, University Children’s Hospital, Münster, Germany
| | - René J.M. Bindels
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, the Netherlands
| | | | - Rosa Vargas-Poussou
- Reference Center for Hereditary Kidney and Childhood Diseases (Maladies Rénales Héréditaires de l’Enfant et de l’Adulte, MARHEA), Paris, France
- Department of Genetics, Hôpital Européen Georges-Pompidou, Assistance Publique Hôpitaux de Paris, Paris, France
- Clinical Investigations Center, Hôpital Européen Georges-Pompidou, Assistance Publique Hôpitaux de Paris, Paris, France
| | - Jeroen H.F. de Baaij
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, the Netherlands
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8
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Role of inwardly rectifying K+ channel 5.1 (Kir5.1) in the regulation of renal membrane transport. Curr Opin Nephrol Hypertens 2022; 31:479-485. [PMID: 35894283 DOI: 10.1097/mnh.0000000000000817] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE OF REVIEW Kir5.1 interacts with Kir4.2 in proximal tubule and with Kir4.1 in distal convoluted tubule (DCT), connecting tubule (CNT) and cortical collecting duct (CCD) to form basolateral-K+-channels. Kir4.2/Kir5.1 and Kir4.1/Kir5.1 play an important role in regulating Na+/HCO3--transport of the proximal tubule and Na+/K+ -transport in the DCT/CNT/CCD. The main focus of this review is to provide an overview of the recent development in the field regarding the role of Kir5.1 regulating renal electrolyte transport in the proximal tubule and DCT. RECENT FINDINGS Loss-of-function-mutations of KCNJ16 cause a new form of tubulopathy, characterized by hypokalaemia, Na+-wasting, acid-base-imbalance and metabolic-acidosis. Abnormal bicarbonate transport induced by loss-of-function of KCNJ16-mutants is recapitulated in Kir4.2-knockout-(Kir4.2 KO) mice. Deletion of Kir5.1 also abolishes the effect of dietary Na+ and K+-intakes on the basolateral membrane voltage and NCC expression/activity. Long-term high-salt intake or high-K+-intake causes hyperkalaemic in Kir5.1-deficient mice. SUMMARY Kir4.2/Kir5.1 activity in the proximal tubule plays a key role in regulating Na+, K+ and bicarbonate-transport through regulating electrogenic-Na+-bicarbonate-cotransporter-(NBCe1) and type 3-Na+/H+-exchanger-(NHE3). Kir4.1/Kir5.1 activity of the DCT plays a critical role in mediating the effect of dietary-K+ and Na+-intakes on NCC activity/expression. As NCC determines the Na+ delivery rate to the aldosterone-sensitive distal nephron (ASDN), defective regulation of NCC during high-salt and high-K+ compromises renal K+ excretion and K+ homeostasis.
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9
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Wang WH, Lin DH. Inwardly rectifying K + channels 4.1 and 5.1 (Kir4.1/Kir5.1) in the renal distal nephron. Am J Physiol Cell Physiol 2022; 323:C277-C288. [PMID: 35759440 PMCID: PMC9291425 DOI: 10.1152/ajpcell.00096.2022] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The inwardly rectifying potassium channel (Kir) 4.1 (encoded by KCNJ10) interacts with Kir5.1 (encoded by KCNJ16) to form a major basolateral K+ channel in the renal distal convoluted tubule (DCT), connecting tubule (CNT), and the cortical collecting duct (CCD). Kir4.1/Kir5.1 heterotetramer plays an important role in regulating Na+ and K+ transport in the DCT, CNT, and CCD. A recent development in the field has firmly established the role of Kir4.1/Kir5.1 heterotetramer of the DCT in the regulation of thiazide-sensitive Na-Cl cotransporter (NCC). Changes in Kir4.1/Kir5.1 activity of the DCT are an essential step for the regulation of NCC expression/activity induced by dietary K+ and Na+ intakes and play a role in modulating NCC by type 2 angiotensin II receptor (AT2R), bradykinin type II receptor (BK2R), and β-adrenergic receptor. Since NCC activity determines the Na+ delivery rate to the aldosterone-sensitive distal nephron (ASDN), a distal nephron segment from late DCT to CCD, Kir4.1/Kir5.1 activity plays a critical role not only in the regulation of renal Na+ absorption but also in modulating renal K+ excretion and maintaining K+ homeostasis. Thus, Kir4.1/Kir5.1 activity serves as an important component of renal K+ sensing mechanism. The main focus of this review is to provide an overview regarding the role of Kir4.1 and Kir5.1 of the DCT and CCD in the regulation of renal K+ excretion and Na+ absorption.
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Affiliation(s)
- Wen-Hui Wang
- Department of Pharmacology, New York Medical College, Valhalla, New York
| | - Dao-Hong Lin
- Department of Pharmacology, New York Medical College, Valhalla, New York
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10
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Lo J, Forst AL, Warth R, Zdebik AA. EAST/SeSAME Syndrome and Beyond: The Spectrum of Kir4.1- and Kir5.1-Associated Channelopathies. Front Physiol 2022; 13:852674. [PMID: 35370765 PMCID: PMC8965613 DOI: 10.3389/fphys.2022.852674] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Accepted: 02/08/2022] [Indexed: 12/13/2022] Open
Abstract
In 2009, two groups independently linked human mutations in the inwardly rectifying K+ channel Kir4.1 (gene name KCNJ10) to a syndrome affecting the central nervous system (CNS), hearing, and renal tubular salt reabsorption. The autosomal recessive syndrome has been named EAST (epilepsy, ataxia, sensorineural deafness, and renal tubulopathy) or SeSAME syndrome (seizures, sensorineural deafness, ataxia, intellectual disability, and electrolyte imbalance), accordingly. Renal dysfunction in EAST/SeSAME patients results in loss of Na+, K+, and Mg2+ with urine, activation of the renin-angiotensin-aldosterone system, and hypokalemic metabolic alkalosis. Kir4.1 is highly expressed in affected organs: the CNS, inner ear, and kidney. In the kidney, it mostly forms heteromeric channels with Kir5.1 (KCNJ16). Biallelic loss-of-function mutations of Kir5.1 can also have disease significance, but the clinical symptoms differ substantially from those of EAST/SeSAME syndrome: although sensorineural hearing loss and hypokalemia are replicated, there is no alkalosis, but rather acidosis of variable severity; in contrast to EAST/SeSAME syndrome, the CNS is unaffected. This review provides a framework for understanding some of these differences and will guide the reader through the growing literature on Kir4.1 and Kir5.1, discussing the complex disease mechanisms and the variable expression of disease symptoms from a molecular and systems physiology perspective. Knowledge of the pathophysiology of these diseases and their multifaceted clinical spectrum is an important prerequisite for making the correct diagnosis and forms the basis for personalized therapies.
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Affiliation(s)
- Jacky Lo
- Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom
| | - Anna-Lena Forst
- Medical Cell Biology, Institute of Physiology, University of Regensburg, Regensburg, Germany
| | - Richard Warth
- Medical Cell Biology, Institute of Physiology, University of Regensburg, Regensburg, Germany
| | - Anselm A. Zdebik
- Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom
- Centre for Nephrology, University College London, London, United Kingdom
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11
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Reyes JV, Medina PMB. Renal calcium and magnesium handling in Gitelman syndrome. Am J Transl Res 2022; 14:1-19. [PMID: 35173827 PMCID: PMC8829599] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Accepted: 11/24/2021] [Indexed: 06/14/2023]
Abstract
Gitelman syndrome (GS) is an autosomal recessive salt-losing tubulopathy caused by biallelic inactivating mutations in the SLC12A3 gene. This gene encodes the thiazide-sensitive sodium-chloride cotransporter (NCC) which is exclusively expressed in the distal convoluted tubules (DCT). GS patients classically present with hypokalemic metabolic alkalosis with hypocalciuria and hypomagnesemia. While hypokalemia and metabolic alkalosis are easily explained by effects of the genotypic defect in GS, the mechanisms by which hypomagnesemia and hypocalciuria develop in GS are poorly understood. In this review, we aim to achieve three major objectives. First, present a concise discussion about current understanding on physiologic calcium and magnesium handling in the DCT. Second, integrate expression data from studies on calciotropic and magnesiotropic proteins relevant to the GS disease state. Lastly, provide insights into the possible mechanisms of calcium-magnesium crosstalk relating to the co-occurrence of hypocalciuria and hypomagnesemia in GS models. Our analyses highlight specific areas of study that are valuable in elucidating possible molecular pathways of hypocalciuria and hypomagnesemia in GS.
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Affiliation(s)
- Jeremiah V Reyes
- Biological Models Laboratory, Department of Biochemistry and Molecular Biology, College of Medicine, University of the Philippines Manila Ermita, Manila 1000, Philippines
| | - Paul Mark B Medina
- Biological Models Laboratory, Department of Biochemistry and Molecular Biology, College of Medicine, University of the Philippines Manila Ermita, Manila 1000, Philippines
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12
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Grahammer F, Huber TB, Artunc F. Role of mTOR Signaling for Tubular Function and Disease. Physiology (Bethesda) 2021; 36:350-358. [PMID: 34514872 DOI: 10.1152/physiol.00021.2021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The mechanistic target of rapamycin (mTOR) forms two distinct intracellular multiprotein complexes that control a multitude of intracellular processes linked to metabolism, proliferation, actin cytoskeleton, and survival. Recent studies have identified the importance of these complexes for transport regulation of ions and nutrients along the entire nephron. First reports could link altered activity of these complexes to certain disease entities, i.e. diabetic nephropathy, acute kidney injury or hyperkalemia.
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Affiliation(s)
- Florian Grahammer
- Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Tobias B Huber
- Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Ferruh Artunc
- Department of Internal Medicine, Division of Endocrinology, Diabetology, and Nephrology, University Hospital Tübingen, Tübingen, Germany.,Institute of Diabetes Research and Metabolic Diseases, Helmholtz Center Munich, University Tübingen, Tübingen, Germany.,German Center for Diabetes Research, University Tübingen, Tübingen, Germany
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13
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Xiao Y, Duan XP, Zhang DD, Wang WH, Lin DH. Deletion of renal Nedd4-2 abolishes the effect of high K + intake on Kir4.1/Kir5.1 and NCC activity in the distal convoluted tubule. Am J Physiol Renal Physiol 2021; 321:F1-F11. [PMID: 34029145 DOI: 10.1152/ajprenal.00072.2021] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
High-dietary K+ (HK) intake inhibits basolateral Kir4.1/Kir5.1 activity in the distal convoluted tubule (DCT), and HK-induced inhibition of Kir4.1/Kir5.1 is essential for HK-induced inhibition of NaCl cotransporter (NCC). Here, we examined whether neural precursor cell expressed developmentally downregulated 4-2 (Nedd4-2) deletion compromises the effect of HK on basolateral Kir4.1/Kir5.1 and NCC in the DCT. Single-channel recording and whole cell recording showed that neither HK decreased nor low-dietary K+ (LK) increased basolateral Kir4.1/Kir5.1 activity of the DCT in kidney tubule-specific Nedd4-2 knockout (Ks-Nedd4-2 KO) mice. In contrast, HK inhibited and LK increased Kir4.1/Kir5.1 activity in control mice [neural precursor cell expressed developmentally downregulated 4-like (Nedd4l)flox/flox]. Also, HK intake decreased the negativity of K+ current reversal potential in the DCT (depolarization) only in control mice but not in Ks-Nedd4-2 KO mice. Renal clearance experiments showed that HK intake decreased, whereas LK intake increased, hydrochlorothiazide-induced renal Na+ excretion only in control mice, but this effect was absent in Ks-Nedd4-2 KO mice. Western blot analysis also demonstrated that HK-induced inhibition of phosphorylated NCC (Thr53) and total NCC was observed only in control mice but not in Ks-Nedd4-2 KO mice. Furthermore, expression of all three subunits of the epithelial Na+ channel in Ks-Nedd4-2 KO mice on HK was higher than in control mice. Thus, plasma K+ concentrations were similar between Nedd4lflox/flox and Ks-Nedd4-2 KO mice on HK for 7 days despite high NCC expression. We conclude that Nedd4-2 plays a role in regulating HK-induced inhibition of Kir4.1/Kir5.1 and NCC in the DCT.NEW & NOTEWORTHY Basolateral Kir4.1/Kir5.1 in the distal convoluted tubule plays an important role as a "K+ sensor" in the regulation of renal K+ excretion after high K+ intake. We found that neural precursor cell expressed developmentally downregulated 4-2 (Nedd4-2) a role in mediating the effect of K+ diet on Kir4.1/Kir5.1 and NaCl cotransporter because high K+ intake failed to inhibit basolateral Kir4.1/Kir5.1 and NaCl cotransporter in kidney tubule-specific Nedd4-2 knockout mice.
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Affiliation(s)
- Yu Xiao
- Department of Physiology, Qiqihar Medical College, Heilongjiang, China.,Department of Pharmacology, New York Medical College, Valhalla, New York
| | - Xin-Peng Duan
- Department of Pharmacology, New York Medical College, Valhalla, New York
| | - Dan-Dan Zhang
- Department of Pharmacology, New York Medical College, Valhalla, New York
| | - Wen-Hui Wang
- Department of Pharmacology, New York Medical College, Valhalla, New York
| | - Dao-Hong Lin
- Department of Pharmacology, New York Medical College, Valhalla, New York
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14
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Duan XP, Wu P, Zhang DD, Gao ZX, Xiao Y, Ray EC, Wang WH, Lin DH. Deletion of Kir5.1 abolishes the effect of high Na + intake on Kir4.1 and Na +-Cl - cotransporter. Am J Physiol Renal Physiol 2021; 320:F1045-F1058. [PMID: 33900854 DOI: 10.1152/ajprenal.00004.2021] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
High sodium (HS) intake inhibited epithelial Na+ channel (ENaC) in the aldosterone-sensitive distal nephron and Na+-Cl- cotransporter (NCC) by suppressing basolateral Kir4.1/Kir5.1 in the distal convoluted tubule (DCT), thereby increasing renal Na+ excretion but not affecting K+ excretion. The aim of the present study was to explore whether deletion of Kir5.1 compromises the inhibitory effect of HS on NCC expression/activity and renal K+ excretion. Patch-clamp experiments demonstrated that HS failed to inhibit DCT basolateral K+ channels and did not depolarize K+ current reversal potential of the DCT in Kir5.1 knockout (KO) mice. Moreover, deletion of Kir5.1 not only increased the expression of Kir4.1, phospho-NCC, and total NCC but also abolished the inhibitory effect of HS on the expression of Kir4.1, phospho-NCC, and total NCC and thiazide-induced natriuresis. Also, low sodium-induced stimulation of NCC expression/activity and basolateral K+ channels in the DCT were absent in Kir5.1 KO mice. Deletion of Kir5.1 decreased ENaC currents in the late DCT, and HS further inhibited ENaC activity in Kir5.1 KO mice. Finally, measurement of the basal renal K+ excretion rate with the modified renal clearance method demonstrated that long-term HS inhibited the renal K+ excretion rate and steadily increased plasma K+ levels in Kir5.1 KO mice but not in wild-type mice. We conclude that Kir5.1 plays an important role in mediating the effect of HS intake on basolateral K+ channels in the DCT and NCC activity/expression. Kir5.1 is involved in maintaining renal ability of K+ excretion during HS intake. NEW & NOTEWORTHY Kir5.1 plays an important role in mediating the effect of high sodium intake on basolateral K+ channels in the distal convoluted tubule and Na+-Cl- cotransporter activity/expression.
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Affiliation(s)
- Xin-Peng Duan
- Department of Pharmacology, New York Medical College, Valhalla, New York.,Department of Histology and Embryology, Xuzhou Medical University, Xuzhou, People's Republic of China
| | - Peng Wu
- Department of Pharmacology, New York Medical College, Valhalla, New York.,Institute of Hypertension and Kidney Disease, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, People's Republic of China
| | - Dan-Dan Zhang
- Department of Pharmacology, New York Medical College, Valhalla, New York.,Guangdong-Hong Kong Joint Laboratory on Immunological and Genetic Kidney Diseases, Guangdong Academy of Medical Sciences, Guangdong Provincial People's Hospital, Guangzhou, People's Republic of China
| | - Zhong-Xiuzi Gao
- Department of Pharmacology, New York Medical College, Valhalla, New York.,Institute of Hypertension and Kidney Disease, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, People's Republic of China
| | - Yu Xiao
- Department of Pharmacology, New York Medical College, Valhalla, New York.,Department of Physiology, Qiqihar Medical University, Qiqihar, People's Republic of China
| | - Evan C Ray
- Renal-Electrolyte Division, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Wen-Hui Wang
- Department of Pharmacology, New York Medical College, Valhalla, New York
| | - Dao-Hong Lin
- Department of Pharmacology, New York Medical College, Valhalla, New York
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15
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Weaver CD, Denton JS. Next-generation inward rectifier potassium channel modulators: discovery and molecular pharmacology. Am J Physiol Cell Physiol 2021; 320:C1125-C1140. [PMID: 33826405 DOI: 10.1152/ajpcell.00548.2020] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Inward rectifying potassium (Kir) channels play important roles in both excitable and nonexcitable cells of various organ systems and could represent valuable new drug targets for cardiovascular, metabolic, immune, and neurological diseases. In nonexcitable epithelial cells of the kidney tubule, for example, Kir1.1 (KCNJ1) and Kir4.1 (KCNJ10) are linked to sodium reabsorption in the thick ascending limb of Henle's loop and distal convoluted tubule, respectively, and have been explored as novel-mechanism diuretic targets for managing hypertension and edema. G protein-coupled Kir channels (Kir3) channels expressed in the central nervous system are critical effectors of numerous signal transduction pathways underlying analgesia, addiction, and respiratory-depressive effects of opioids. The historical dearth of pharmacological tool compounds for exploring the therapeutic potential of Kir channels has led to a molecular target-based approach using high-throughput screen (HTS) of small-molecule libraries and medicinal chemistry to develop "next-generation" Kir channel modulators that are both potent and specific for their targets. In this article, we review recent efforts focused specifically on discovery and improvement of target-selective molecular probes. The reader is introduced to fluorescence-based thallium flux assays that have enabled much of this work and then provided with an overview of progress made toward developing modulators of Kir1.1 (VU590, VU591), Kir2.x (ML133), Kir3.X (ML297, GAT1508, GiGA1, VU059331), Kir4.1 (VU0134992), and Kir7.1 (ML418). We discuss what is known about the small molecules' molecular mechanisms of action, in vitro and in vivo pharmacology, and then close with our view of what critical work remains to be done.
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Affiliation(s)
- C David Weaver
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee.,Department of Chemistry, Vanderbilt University, Nashville, Tennessee.,Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee
| | - Jerod S Denton
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee.,Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee.,Department of Anesthesiology, Vanderbilt University Medical Center, Nashville, Tennessee
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16
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Zhang DD, Duan XP, Xiao Y, Wu P, Gao ZX, Wang WH, Lin DH. Deletion of renal Nedd4-2 abolishes the effect of high sodium intake (HS) on Kir4.1, ENaC, and NCC and causes hypokalemia during high HS. Am J Physiol Renal Physiol 2021; 320:F883-F896. [PMID: 33818128 DOI: 10.1152/ajprenal.00555.2020] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Neural precursor cell expressed developmentally downregulated protein 4-2 (Nedd4-2) regulates the expression of Kir4.1, thiazide-sensitive NaCl cotransporter (NCC), and epithelial Na+ channel (ENaC) in the aldosterone-sensitive distal nephron (ASDN), and Nedd4-2 deletion causes salt-sensitive hypertension. We now examined whether Nedd4-2 deletion compromises the effect of high-salt (HS) diet on Kir4.1, NCC, ENaC, and renal K+ excretion. Immunoblot analysis showed that HS diet decreased the expression of Kir4.1, Ca2+-activated large-conductance K+ channel subunit-α (BKα), ENaCβ, ENaCγ, total NCC, and phospho-NCC (at Thr53) in floxed neural precursor cell expressed developmentally downregulated gene 4-like (Nedd4lfl/fl) mice, whereas these effects were absent in kidney-specific Nedd4-2 knockout (Ks-Nedd4-2 KO) mice. Renal clearance experiments also demonstrated that Nedd4-2 deletion abolished the inhibitory effect of HS diet on hydrochlorothiazide-induced natriuresis. Patch-clamp experiments showed that neither HS diet nor low-salt diet had an effect on Kir4.1/Kir5.1 currents of the distal convoluted tubule in Nedd4-2-deficient mice, whereas we confirmed that HS diet inhibited and low-salt diet increased Kir4.1/Kir5.1 activity in Nedd4lflox/flox mice. Nedd4-2 deletion increased ENaC currents in the ASDN, and this increase was more robust in the cortical collecting duct than in the distal convoluted tubule. Also, HS-induced inhibition of ENaC currents in the ASDN was absent in Nedd4-2-deficient mice. Renal clearance experiments showed that HS intake for 2 wk increased the basal level of renal K+ excretion and caused hypokalemia in Ks-Nedd4-2-KO mice but not in Nedd4lflox/flox mice. In contrast, plasma Na+ concentrations were similar in Nedd4lflox/flox and Ks-Nedd4-2 KO mice on HS diet. We conclude that Nedd4-2 plays an important role in mediating the inhibitory effect of HS diet on Kir4.1, ENaC, and NCC and is essential for maintaining normal renal K+ excretion and plasma K+ ranges during long-term HS diet.NEW & NOTEWORTHY The present study suggests that Nedd4-2 is involved in mediating the inhibitory effect of high salt (HS) diet on Kir4.1/kir5.1 in the distal convoluted tubule, NaCl cotransporter function, and epithelial Na+ channel activity and that Nedd4-2 plays an essential role in maintaining K+ homeostasis in response to a long-term HS diet. This suggests the possibility that HS intake could lead to hypokalemia in subjects lacking proper Nedd4-2 E3 ubiquitin ligase activity in aldosterone-sensitive distal nephron.
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Affiliation(s)
- Dan-Dan Zhang
- Guangdong-Hong Kong Joint Laboratory on Immunological and Genetic Kidney Diseases, Guangdong Academy of Medical Sciences, Guangdong Provincial People's Hospital, Guangzhou, China.,Department of Pharmacology, New York Medical College, Valhalla, New York
| | - Xin-Peng Duan
- Department of Pharmacology, New York Medical College, Valhalla, New York
| | - Yu Xiao
- Department of Physiology, Qiqihar Medical College, Heilongjiang, China.,Department of Pharmacology, New York Medical College, Valhalla, New York
| | - Peng Wu
- Department of Pharmacology, New York Medical College, Valhalla, New York
| | - Zhong-Xiuzi Gao
- Department of Pharmacology, New York Medical College, Valhalla, New York
| | - Wen-Hui Wang
- Department of Pharmacology, New York Medical College, Valhalla, New York
| | - Dao-Hong Lin
- Department of Pharmacology, New York Medical College, Valhalla, New York
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Bovée DM, Cuevas CA, Zietse R, Danser AHJ, Mirabito Colafella KM, Hoorn EJ. Salt-sensitive hypertension in chronic kidney disease: distal tubular mechanisms. Am J Physiol Renal Physiol 2020; 319:F729-F745. [DOI: 10.1152/ajprenal.00407.2020] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Chronic kidney disease (CKD) causes salt-sensitive hypertension that is often resistant to treatment and contributes to the progression of kidney injury and cardiovascular disease. A better understanding of the mechanisms contributing to salt-sensitive hypertension in CKD is essential to improve these outcomes. This review critically explores these mechanisms by focusing on how CKD affects distal nephron Na+ reabsorption. CKD causes glomerulotubular imbalance with reduced proximal Na+ reabsorption and increased distal Na+ delivery and reabsorption. Aldosterone secretion further contributes to distal Na+ reabsorption in CKD and is not only mediated by renin and K+ but also by metabolic acidosis, endothelin-1, and vasopressin. CKD also activates the intrarenal renin-angiotensin system, generating intratubular angiotensin II to promote distal Na+ reabsorption. High dietary Na+ intake in CKD contributes to Na+ retention by aldosterone-independent activation of the mineralocorticoid receptor mediated through Rac1. High dietary Na+ also produces an inflammatory response mediated by T helper 17 cells and cytokines increasing distal Na+ transport. CKD is often accompanied by proteinuria, which contains plasmin capable of activating the epithelial Na+ channel. Thus, CKD causes both local and systemic changes that together promote distal nephron Na+ reabsorption and salt-sensitive hypertension. Future studies should address remaining knowledge gaps, including the relative contribution of each mechanism, the influence of sex, differences between stages and etiologies of CKD, and the clinical relevance of experimentally identified mechanisms. Several pathways offer opportunities for intervention, including with dietary Na+ reduction, distal diuretics, renin-angiotensin system inhibitors, mineralocorticoid receptor antagonists, and K+ or H+ binders.
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Affiliation(s)
- Dominique M. Bovée
- Division of Nephrology and Transplantation, Department of Internal Medicine, Erasmus MC, Erasmus University Medical Center, Rotterdam, The Netherlands
- Division of Vascular Medicine, Department of Internal Medicine, Erasmus MC, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Catharina A. Cuevas
- Division of Nephrology and Transplantation, Department of Internal Medicine, Erasmus MC, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Robert Zietse
- Division of Nephrology and Transplantation, Department of Internal Medicine, Erasmus MC, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - A. H. Jan Danser
- Division of Vascular Medicine, Department of Internal Medicine, Erasmus MC, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Katrina M. Mirabito Colafella
- Cardiovascular Disease Program, Monash Biomedicine Discovery Institute, Monash University, Melbourne, Victoria, Australia
- Department of Physiology, Monash University, Melbourne, Victoria, Australia
| | - Ewout J. Hoorn
- Division of Nephrology and Transplantation, Department of Internal Medicine, Erasmus MC, Erasmus University Medical Center, Rotterdam, The Netherlands
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18
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Wang LJ, Xiao Y, Fang J, Wang JL, Zhang H, Meng XX, Gong RL, Gu R. PGF2α stimulates the 10-pS Cl− channel and thiazide-sensitive Na+-Cl− cotransporter in the distal convoluted tubule. Am J Physiol Renal Physiol 2020; 319:F414-F422. [DOI: 10.1152/ajprenal.00287.2020] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
We used patch-clamp and Western blot analysis to test whether PGF2α stimulates the basolateral 10-pS Cl− channel and thiazide-sensitive Na+-Cl− cotransporter (NCC) in the distal convoluted tubule (DCT) via a prostaglandin F receptor (FP-R). Single channel and whole cell recordings demonstrated that PGF2α stimulated the 10-pS Cl− channel in the DCT. The stimulatory effect of PGF2α on the Cl− channel was mimicked by a FP-R agonist, latanoprost, but was abrogated by blocking FP-R with AL8810. Also, the effect of PGF2α on the Cl− channel in the DCT was recapitulated by stimulating PKC but was blocked by inhibiting PKC. Furthermore, inhibition of p38 MAPK but not ERK blocked the effect of PGF2α on the 10-pS Cl− channel. Inhibition of NADPH oxidase also abrogated the stimulatory effect of PGF2α on the 10-pS Cl− channel, while the addition of 10 μM H2O2 mimicked the stimulatory effect of PGF2α on the 10-pS Cl− channel. Moreover, superoxide-related species may mediate the stimulatory effect of PGF2α on the 10-pS Cl− channel because the stimulatory effect of PGF2α and H2O2 was not additive. Western blot analysis showed that infusion of PGF2α in vivo not only increased the expression of FP-R but also increased the expression of total NCC and phosphorylated NCC. We conclude that PGF2α stimulates the basolateral 10-pS Cl− channel in the DCT by activating FP-R through PKC/p38 MAPK and NADPH oxidase-dependent pathways. The stimulatory effects of PGF2α on the Cl− channel and NCC may contribute to PGF2α-induced increases in NaCl reabsorption in the DCT.
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Affiliation(s)
- Li-Jun Wang
- Department of Physiology, Harbin Medical University, Harbin, China
| | - Yu Xiao
- Department of Physiology, Harbin Medical University, Harbin, China
| | - Jing Fang
- Department of Physiology, Harbin Medical University, Harbin, China
| | - Jun-Lin Wang
- Department of Physiology, Harbin Medical University, Harbin, China
| | - Hao Zhang
- Department of Physiology, Harbin Medical University, Harbin, China
| | - Xin-Xin Meng
- Department of Physiology, Harbin Medical University, Harbin, China
| | - Rui-Lan Gong
- Department of Physiology, Harbin Medical University, Harbin, China
| | - Ruimin Gu
- Department of Physiology, Harbin Medical University, Harbin, China
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Vio CP, Gallardo P, Cespedes C, Salas D, Diaz-Elizondo J, Mendez N. Dietary Potassium Downregulates Angiotensin-I Converting Enzyme, Renin, and Angiotensin Converting Enzyme 2. Front Pharmacol 2020; 11:920. [PMID: 32625100 PMCID: PMC7314933 DOI: 10.3389/fphar.2020.00920] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2019] [Accepted: 06/05/2020] [Indexed: 12/16/2022] Open
Abstract
Background The importance of dietary potassium in health and disease has been underestimated compared with that placed on dietary sodium. Larger effort has been made on reduction of sodium intake and less on the adequate dietary potassium intake, although natural food contains much more potassium than sodium. The benefits of a potassium-rich diet are known, however, the mechanism by which it exerts its preventive action, remains to be elucidated. With the hypothesis that dietary potassium reduces renal vasoconstrictor components of the renin-angiotensin system in the long-term, we studied the effect of high potassium diet on angiotensin-I converting enzyme, renin, and angiotensin converting enzyme 2. Methods Sprague Dawley male rats on a normal sodium diet received normal potassium (0.9%, NK) or high potassium diet (3%, HK) for 4 weeks. Urine was collected in metabolic cages for electrolytes and urinary volume measurement. Renal tissue was used to analyze angiotensin-I converting enzyme, renin, and angiotensin converting enzyme 2 expression. Protein abundance analysis was done by Western blot; gene expression by mRNA levels by RT-qPCR. Renal distribution of angiotensin-I converting enzyme and renin was done by immunohistochemistry and morphometric analysis in coded samples. Results High potassium diet (4 weeks) reduced the levels of renin, angiotensin-I converting enzyme, and angiotensin converting enzyme 2. Angiotensin-I converting enzyme was located in the brush border of proximal tubules and with HK diet decreased the immunostaining intensity (P < 0.05), decreased the mRNA (P < 0.01) and the protein levels (P < 0.01). Renin localization was restricted to granular cells of the afferent arteriole and HK diet decreased the number of renin positive cells (P < 0.01) and renin mRNA levels (P < 0.01). High potassium intake decreased angiotensin converting enzyme 2 gene expression and protein levels (P < 0.01).No morphological abnormalities were observed in renal tissue during high potassium diet.The reduced expression of angiotensin-I converting enzyme, renin, and angiotensin converting enzyme 2 during potassium supplementation suggest that high dietary potassium intake could modulate these vasoactive enzymes and this effects can contribute to the preventive and antihypertensive effect of potassium.
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Affiliation(s)
- Carlos P Vio
- Center for Aging and Regeneration CARE UC, Department of Physiology, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile.,Facultad de Medicina y Ciencia, Universidad San Sebastian, Santiago, Chile
| | - Pedro Gallardo
- Facultad de Medicina, Escuela de Medicina, Universidad Finis Terrae, Santiago, Chile
| | - Carlos Cespedes
- Center for Aging and Regeneration CARE UC, Department of Physiology, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile.,Facultad de Medicina y Ciencia, Universidad San Sebastian, Santiago, Chile
| | - Daniela Salas
- Center for Aging and Regeneration CARE UC, Department of Physiology, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Jessica Diaz-Elizondo
- Center for Aging and Regeneration CARE UC, Department of Physiology, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Natalia Mendez
- Facultad de Medicina, Institute of Anatomy, Histology and Pathology, Universidad Austral de Chile, Valdivia, Chile
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20
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Wang MX, Wang LJ, Xiao Y, Zhang DD, Duan XP, Wang WH. Epoxyeicosatrienoic acid metabolites inhibit Kir4.1/Kir5.1 in the distal convoluted tubule. Am J Physiol Renal Physiol 2020; 318:F1369-F1376. [PMID: 32308018 PMCID: PMC7311705 DOI: 10.1152/ajprenal.00018.2020] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Revised: 03/12/2020] [Accepted: 04/13/2020] [Indexed: 11/22/2022] Open
Abstract
Cytochrome P-450 (Cyp) epoxygenase-dependent metabolites of arachidonic acid (AA) have been shown to inhibit renal Na+ transport, and inhibition of Cyp-epoxygenase is associated with salt-sensitive hypertension. We used the patch-clamp technique to examine whether Cyp-epoxygenase-dependent AA metabolites inhibited the basolateral 40-pS K+ channel (Kir4.1/Kir5.1) in the distal convoluted tubule (DCT). Application of AA inhibited the basolateral 40-pS K+ channel in the DCT. The inhibitory effect of AA on the 40-pS K+ channel was specific because neither linoleic nor oleic acid was able to mimic the effect of AA on the K+ channel. Inhibition of Cyp-monooxygenase with N-methylsulfonyl-12,12-dibromododec-11-enamide or inhibition of cyclooxygenase with indomethacin failed to abolish the inhibitory effect of AA on the 40-pS K+ channel. However, the inhibition of Cyp-epoxygenase with N-methylsulfonyl-6-(propargyloxyphenyl)hexanamide abolished the effect of AA on the 40-pS K+ channel in the DCT. Moreover, addition of either 11,12-epoxyeicosatrienoic acid (EET) or 14,15-EET also inhibited the 40-pS K+ channel in the DCT. Whole cell recording demonstrated that application of AA decreased, whereas N-methylsulfonyl-6-(propargyloxyphenyl)hexanamide treatment increased, Ba2+-sensitive K+ currents in the DCT. Finally, application of 14,15-EET but not AA was able to inhibit the basolateral 40-pS K+ channel in the DCT of Cyp2c44-/- mice. We conclude that Cyp-epoxygenase-dependent AA metabolites inhibit the basolateral Kir4.1/Kir5.1 in the DCT and that Cyp2c44-epoxygenase plays a role in the regulation of the basolateral K+ channel in the mouse DCT.
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MESH Headings
- 8,11,14-Eicosatrienoic Acid/analogs & derivatives
- 8,11,14-Eicosatrienoic Acid/metabolism
- 8,11,14-Eicosatrienoic Acid/pharmacology
- Amides/pharmacology
- Animals
- Arachidonic Acid/metabolism
- Arachidonic Acid/pharmacology
- Cytochrome P450 Family 2/antagonists & inhibitors
- Cytochrome P450 Family 2/genetics
- Cytochrome P450 Family 2/metabolism
- Enzyme Inhibitors/pharmacology
- Kidney Tubules, Distal/drug effects
- Kidney Tubules, Distal/metabolism
- Male
- Membrane Potentials
- Mice, 129 Strain
- Mice, Knockout
- Potassium Channel Blockers/metabolism
- Potassium Channel Blockers/pharmacology
- Potassium Channels, Inwardly Rectifying/antagonists & inhibitors
- Potassium Channels, Inwardly Rectifying/metabolism
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Affiliation(s)
- Ming-Xiao Wang
- Department of Physiology, Zhuhai Campus of Zunyi Medical University, Zunyi, Guizhou, China
| | - Li-Jun Wang
- Department of Physiology, Harbin Medical University, Harbin, China
| | - Yu Xiao
- Department of Physiology, Qiqihar Medical College, Heilongjiang, China
| | - Dan-Dan Zhang
- Department of Pharmacology, New York Medical College, Valhalla, New York
| | - Xin-Peng Duan
- Department of Pharmacology, New York Medical College, Valhalla, New York
| | - Wen-Hui Wang
- Department of Pharmacology, New York Medical College, Valhalla, New York
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21
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Wu P, Su XT, Gao ZX, Zhang DD, Duan XP, Xiao Y, Staub O, Wang WH, Lin DH. Renal Tubule Nedd4-2 Deficiency Stimulates Kir4.1/Kir5.1 and Thiazide-Sensitive NaCl Cotransporter in Distal Convoluted Tubule. J Am Soc Nephrol 2020; 31:1226-1242. [PMID: 32295826 DOI: 10.1681/asn.2019090923] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Accepted: 03/07/2020] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND The potassium channel Kir4.1 forms the Kir4.1/Kir5.1 heterotetramer in the basolateral membrane of the distal convoluted tubule (DCT) and plays an important role in the regulation of the thiazide-sensitive NaCl cotransporter (NCC). Kidney-specific deletion of the ubiquitin ligase Nedd4-2 increases expression of NCC, and coexpression of Nedd4-2 inhibits Kir4.1/Kir5.1 in vitro. Whether Nedd4-2 regulates NCC expression in part by regulating Kir4.1/Kir5.1 channel activity in the DCT is unknown. METHODS We used electrophysiology studies, immunoblotting, immunostaining, and renal clearance to examine Kir4.1/Kir5.1 activity in the DCT and NCC expression/activity in wild-type mice and mice with kidney-specific knockout of Nedd4-2, Kir4.1, or both. RESULTS Deletion of Nedd4-2 increased the activity/expression of Kir4.1 in the DCT and also, hyperpolarized the DCT membrane. Expression of phosphorylated NCC/total NCC and thiazide-induced natriuresis were significantly increased in the Nedd4-2 knockout mice, but these mice were normokalemic. Double-knockout mice lacking both Kir4.1/Kir5.1 and Nedd4-2 in the kidney exhibited increased expression of the epithelial sodium channel α-subunit, largely abolished basolateral potassium ion conductance (to a degree similar to that of kidney-specific Kir4.1 knockout mice), and depolarization of the DCT membrane. Compared with wild-type mice, the double-knockout mice displayed inhibited expression of phosphorylated NCC and total NCC and had significantly blunted thiazide-induced natriuresis as well as renal potassium wasting and hypokalemia. However, NCC expression/activity was higher in the double-knockout mice than in Kir4.1 knockout mice. CONCLUSIONS Nedd4-2 regulates Kir4.1/Kir5.1 expression/activity in the DCT and modulates NCC expression by Kir4.1-dependent and Kir4.1-independent mechanisms. Basolateral Kir4.1/Kir5.1 activity in the DCT partially accounts for the stimulation of NCC activity/expression induced by deletion of Nedd4-2.
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Affiliation(s)
- Peng Wu
- Department of Pharmacology, New York Medical College, Valhalla, New York
| | - Xiao-Tong Su
- Department of Pharmacology, New York Medical College, Valhalla, New York
| | - Zhong-Xiuzi Gao
- Department of Pharmacology, New York Medical College, Valhalla, New York
| | - Dan-Dan Zhang
- Department of Pharmacology, New York Medical College, Valhalla, New York
| | - Xin-Peng Duan
- Department of Pharmacology, New York Medical College, Valhalla, New York
| | - Yu Xiao
- Department of Pharmacology, New York Medical College, Valhalla, New York
| | - Olivier Staub
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland
| | - Wen-Hui Wang
- Department of Pharmacology, New York Medical College, Valhalla, New York
| | - Dao-Hong Lin
- Department of Pharmacology, New York Medical College, Valhalla, New York
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22
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Penton D, Vohra T, Banki E, Wengi A, Weigert M, Forst AL, Bandulik S, Warth R, Loffing J. Collecting system-specific deletion of Kcnj10 predisposes for thiazide- and low-potassium diet-induced hypokalemia. Kidney Int 2020; 97:1208-1218. [PMID: 32299681 DOI: 10.1016/j.kint.2019.12.016] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2019] [Revised: 12/20/2019] [Accepted: 12/20/2019] [Indexed: 12/17/2022]
Abstract
The basolateral potassium channel KCNJ10 (Kir4.1), is expressed in the renal distal convoluted tubule and controls the activity of the thiazide-sensitive sodium chloride cotransporter. Loss-of-function mutations of KCNJ10 cause EAST/SeSAME syndrome with salt wasting and severe hypokalemia. KCNJ10 is also expressed in the principal cells of the collecting system. However, its pathophysiological role in this segment has not been studied in detail. To address this, we generated the mouse model AQP2cre:Kcnj10flox/flox with a deletion of Kcnj10 specifically in the collecting system (collecting system-Kcnj10-knockout). Collecting system-Kcnj10-knockout mice responded normally to standard and high potassium diet. However, this knockout exhibited a higher kaliuresis and lower plasma potassium than control mice when treated with thiazide diuretics. Likewise, collecting systemKcnj10-knockout displayed an inadequately high kaliuresis and renal sodium retention upon dietary potassium restriction. In this condition, these knockout mice became hypokalemic due to insufficient downregulation of the epithelial sodium channel (ENaC) and the renal outer medullary potassium channel (ROMK) in the collecting system. Consistently, the phenotype of collecting system-Kcnj10-knockout was fully abrogated by ENaC inhibition with amiloride and ameliorated by genetic inactivation of ROMK in the collecting system. Thus, KCNJ10 in the collecting system contributes to the renal control of potassium homeostasis by regulating ENaC and ROMK. Hence, impaired KCNJ10 function in the collecting system predisposes for thiazide and low potassium diet-induced hypokalemia and likely contributes to the pathophysiology of renal potassium loss in EAST/SeSAME syndrome.
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Affiliation(s)
- David Penton
- Institute of Anatomy, University of Zurich, Zurich, Switzerland; Swiss National Centre of Competence in Research (NCCR) Kidney Control of Homeostasis (Kidney.CH), Zurich, Switzerland
| | - Twinkle Vohra
- Institute of Anatomy, University of Zurich, Zurich, Switzerland
| | - Eszter Banki
- Institute of Anatomy, University of Zurich, Zurich, Switzerland; Swiss National Centre of Competence in Research (NCCR) Kidney Control of Homeostasis (Kidney.CH), Zurich, Switzerland
| | - Agnieszka Wengi
- Institute of Anatomy, University of Zurich, Zurich, Switzerland
| | - Maria Weigert
- Medical Cell Biology, University of Regensburg, Regensburg, Germany
| | - Anna-Lena Forst
- Medical Cell Biology, University of Regensburg, Regensburg, Germany
| | - Sascha Bandulik
- Medical Cell Biology, University of Regensburg, Regensburg, Germany
| | - Richard Warth
- Medical Cell Biology, University of Regensburg, Regensburg, Germany
| | - Johannes Loffing
- Institute of Anatomy, University of Zurich, Zurich, Switzerland; Swiss National Centre of Competence in Research (NCCR) Kidney Control of Homeostasis (Kidney.CH), Zurich, Switzerland.
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23
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Recent insights into sodium and potassium handling by the aldosterone-sensitive distal nephron: a review of the relevant physiology. J Nephrol 2020; 33:431-445. [DOI: 10.1007/s40620-019-00684-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2019] [Accepted: 12/02/2019] [Indexed: 02/07/2023]
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24
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Hoorn EJ, Gritter M, Cuevas CA, Fenton RA. Regulation of the Renal NaCl Cotransporter and Its Role in Potassium Homeostasis. Physiol Rev 2020; 100:321-356. [DOI: 10.1152/physrev.00044.2018] [Citation(s) in RCA: 56] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Daily dietary potassium (K+) intake may be as large as the extracellular K+ pool. To avoid acute hyperkalemia, rapid removal of K+ from the extracellular space is essential. This is achieved by translocating K+ into cells and increasing urinary K+ excretion. Emerging data now indicate that the renal thiazide-sensitive NaCl cotransporter (NCC) is critically involved in this homeostatic kaliuretic response. This suggests that the early distal convoluted tubule (DCT) is a K+ sensor that can modify sodium (Na+) delivery to downstream segments to promote or limit K+ secretion. K+ sensing is mediated by the basolateral K+ channels Kir4.1/5.1, a capacity that the DCT likely shares with other nephron segments. Thus, next to K+-induced aldosterone secretion, K+ sensing by renal epithelial cells represents a second feedback mechanism to control K+ balance. NCC’s role in K+ homeostasis has both physiological and pathophysiological implications. During hypovolemia, NCC activation by the renin-angiotensin system stimulates Na+ reabsorption while preventing K+ secretion. Conversely, NCC inactivation by high dietary K+ intake maximizes kaliuresis and limits Na+ retention, despite high aldosterone levels. NCC activation by a low-K+ diet contributes to salt-sensitive hypertension. K+-induced natriuresis through NCC offers a novel explanation for the antihypertensive effects of a high-K+ diet. A possible role for K+ in chronic kidney disease is also emerging, as epidemiological data reveal associations between higher urinary K+ excretion and improved renal outcomes. This comprehensive review will embed these novel insights on NCC regulation into existing concepts of K+ homeostasis in health and disease.
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Affiliation(s)
- Ewout J. Hoorn
- Department of Internal Medicine, Division of Nephrology and Transplantation, Erasmus Medical Center, University Medical Center Rotterdam, Rotterdam, The Netherlands; and Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Martin Gritter
- Department of Internal Medicine, Division of Nephrology and Transplantation, Erasmus Medical Center, University Medical Center Rotterdam, Rotterdam, The Netherlands; and Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Catherina A. Cuevas
- Department of Internal Medicine, Division of Nephrology and Transplantation, Erasmus Medical Center, University Medical Center Rotterdam, Rotterdam, The Netherlands; and Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Robert A. Fenton
- Department of Internal Medicine, Division of Nephrology and Transplantation, Erasmus Medical Center, University Medical Center Rotterdam, Rotterdam, The Netherlands; and Department of Biomedicine, Aarhus University, Aarhus, Denmark
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25
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Manis AD, Palygin O, Khedr S, Levchenko V, Hodges MR, Staruschenko A. Relationship between the renin-angiotensin-aldosterone system and renal Kir5.1 channels. Clin Sci (Lond) 2019; 133:2449-2461. [PMID: 31799617 PMCID: PMC8474144 DOI: 10.1042/cs20190876] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Revised: 11/13/2019] [Accepted: 12/03/2019] [Indexed: 02/07/2023]
Abstract
Kir5.1 (encoded by the Kcnj16 gene) is an inwardly rectifying K+ (Kir) channel highly expressed in the aldosterone-sensitive distal nephron of the kidney, where it forms a functional channel with Kir4.1. Kir4.1/Kir5.1 channels are responsible for setting the transepithelial voltage in the distal nephron and collecting ducts and are thereby major determinants of fluid and electrolyte distribution. These channels contribute to renal blood pressure control and have been implicated in salt-sensitive hypertension. However, mechanisms pertaining to the impact of K ir4.1/Kir5.1-mediated K+ transport on the renin-angiotensin-aldosterone system (RAAS) remain unclear. Herein, we utilized a knockout of Kcnj16 in the Dahl salt-sensitive rat (SSKcnj16-/-) to investigate the relationship between Kir5.1 and RAAS balance and function in the sensitivity of blood pressure to the dietary Na+/K+ ratio. The knockout of Kcnj16 caused substantial elevations in plasma RAAS hormones (aldosterone and angiotensin peptides) and altered the RAAS response to changing the dietary Na+/K+ ratio. Blocking aldosterone with spironolactone caused rapid mortality in SSKcnj16-/- rats. Supplementation of the diet with high K+ was protective against mortality resulting from aldosterone-mediated mechanisms. Captopril and losartan treatment had no effect on the survival of SSKcnj16-/- rats. However, neither of these drugs prevented mortality of SSKcnj16-/- rats when switched to high Na+ diet. These studies revealed that the knockout of Kcnj16 markedly altered RAAS regulation and function, suggesting Kir5.1 as a key regulator of the RAAS, particularly when exposed to changes in dietary sodium and potassium content.
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Affiliation(s)
- Anna D. Manis
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Oleg Palygin
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI 53226, USA
- Cardiovascular Center, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Sherif Khedr
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI 53226, USA
- Physiology Department, Faculty of Medicine, Ain Shams University, Cairo, Egypt
| | - Vladislav Levchenko
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Matthew R. Hodges
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Alexander Staruschenko
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI 53226, USA
- Cardiovascular Center, Medical College of Wisconsin, Milwaukee, WI 53226, USA
- Clement J. Zablocki VA Medical Center, Milwaukee, WI 53295, USA
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26
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Wu P, Gao ZX, Zhang DD, Su XT, Wang WH, Lin DH. Deletion of Kir5.1 Impairs Renal Ability to Excrete Potassium during Increased Dietary Potassium Intake. J Am Soc Nephrol 2019; 30:1425-1438. [PMID: 31239388 PMCID: PMC6683724 DOI: 10.1681/asn.2019010025] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Accepted: 04/24/2019] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND The basolateral potassium channel in the distal convoluted tubule (DCT), comprising the inwardly rectifying potassium channel Kir4.1/Kir5.1 heterotetramer, plays a key role in mediating the effect of dietary potassium intake on the thiazide-sensitive NaCl cotransporter (NCC). The role of Kir5.1 (encoded by Kcnj16) in mediating effects of dietary potassium intake on the NCC and renal potassium excretion is unknown. METHODS We used electrophysiology, renal clearance, and immunoblotting to study Kir4.1 in the DCT and NCC in Kir5.1 knockout (Kcnj16-/- ) and wild-type (Kcnj16+/+ ) mice fed with normal, high, or low potassium diets. RESULTS We detected a 40-pS and 20-pS potassium channel in the basolateral membrane of the DCT in wild-type and knockout mice, respectively. Compared with wild-type, Kcnj16-/- mice fed a normal potassium diet had higher basolateral potassium conductance, a more negative DCT membrane potential, higher expression of phosphorylated NCC (pNCC) and total NCC (tNCC), and augmented thiazide-induced natriuresis. Neither high- nor low-potassium diets affected the basolateral DCT's potassium conductance and membrane potential in Kcnj16-/- mice. Although high potassium reduced and low potassium increased the expression of pNCC and tNCC in wild-type mice, these effects were absent in Kcnj16-/- mice. High potassium intake inhibited and low intake augmented thiazide-induced natriuresis in wild-type but not in Kcnj16-/- mice. Compared with wild-type, Kcnj16-/- mice with normal potassium intake had slightly lower plasma potassium but were more hyperkalemic with prolonged high potassium intake and more hypokalemic during potassium restriction. CONCLUSIONS Kir5.1 is essential for dietary potassium's effect on NCC and for maintaining potassium homeostasis.
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Affiliation(s)
- Peng Wu
- Department of Pharmacology, New York Medical College, Valhalla, New York
| | - Zhong-Xiuzi Gao
- Department of Pharmacology, New York Medical College, Valhalla, New York
| | - Dan-Dan Zhang
- Department of Pharmacology, New York Medical College, Valhalla, New York
| | - Xiao-Tong Su
- Department of Pharmacology, New York Medical College, Valhalla, New York
| | - Wen-Hui Wang
- Department of Pharmacology, New York Medical College, Valhalla, New York
| | - Dao-Hong Lin
- Department of Pharmacology, New York Medical College, Valhalla, New York
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27
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Poulsen SB, Fenton RA. K
+
and the renin–angiotensin–aldosterone system: new insights into their role in blood pressure control and hypertension treatment. J Physiol 2019; 597:4451-4464. [DOI: 10.1113/jp276844] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Accepted: 05/17/2019] [Indexed: 12/11/2022] Open
Affiliation(s)
- Søren B. Poulsen
- Department of BiomedicineAarhus University Aarhus DK‐8000 Denmark
| | - Robert A. Fenton
- Department of BiomedicineAarhus University Aarhus DK‐8000 Denmark
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