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Han F, Wu S, Dong Y, Liu Y, Sun B, Chen L. Aberrant expression of NEDD4L disrupts mitochondrial homeostasis by downregulating CaMKKβ in diabetic kidney disease. J Transl Med 2024; 22:465. [PMID: 38755664 PMCID: PMC11100153 DOI: 10.1186/s12967-024-05207-6] [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: 02/15/2024] [Accepted: 04/15/2024] [Indexed: 05/18/2024] Open
Abstract
Disturbance in mitochondrial homeostasis within proximal tubules is a critical characteristic associated with diabetic kidney disease (DKD). CaMKKβ/AMPK signaling plays an important role in regulating mitochondrial homeostasis. Despite the downregulation of CaMKKβ in DKD pathology, the underlying mechanism remains elusive. The expression of NEDD4L, which is primarily localized to renal proximal tubules, is significantly upregulated in the renal tubules of mice with DKD. Coimmunoprecipitation (Co-IP) assays revealed a physical interaction between NEDD4L and CaMKKβ. Moreover, deletion of NEDD4L under high glucose conditions prevented rapid CaMKKβ protein degradation. In vitro studies revealed that the aberrant expression of NEDD4L negatively influences the protein stability of CaMKKβ. This study also explored the role of NEDD4L in DKD by using AAV-shNedd4L in db/db mice. These findings confirmed that NEDD4L inhibition leads to a decrease in urine protein excretion, tubulointerstitial fibrosis, and oxidative stress, and mitochondrial dysfunction. Further in vitro studies demonstrated that si-Nedd4L suppressed mitochondrial fission and reactive oxygen species (ROS) production, effects antagonized by si-CaMKKβ. In summary, the findings provided herein provide strong evidence that dysregulated NEDD4L disturbs mitochondrial homeostasis by negatively modulating CaMKKβ in the context of DKD. This evidence underscores the potential of therapeutic interventions targeting NEDD4L and CaMKKβ to safeguard renal tubular function in the management of DKD.
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Affiliation(s)
- Fei Han
- NHC Key Laboratory of Hormones and Development, Tianjin Key Laboratory of Metabolic Diseases, Chu Hsien-I Memorial Hospital Tianjin and Institute of Endocrinology, Tianjin Medical University, Tianjin, 300134, China
| | - Shi Wu
- NHC Key Laboratory of Hormones and Development, Tianjin Key Laboratory of Metabolic Diseases, Chu Hsien-I Memorial Hospital Tianjin and Institute of Endocrinology, Tianjin Medical University, Tianjin, 300134, China
| | - Ya Dong
- NHC Key Laboratory of Hormones and Development, Tianjin Key Laboratory of Metabolic Diseases, Chu Hsien-I Memorial Hospital Tianjin and Institute of Endocrinology, Tianjin Medical University, Tianjin, 300134, China
| | - Yanjie Liu
- NHC Key Laboratory of Hormones and Development, Tianjin Key Laboratory of Metabolic Diseases, Chu Hsien-I Memorial Hospital Tianjin and Institute of Endocrinology, Tianjin Medical University, Tianjin, 300134, China
| | - Bei Sun
- NHC Key Laboratory of Hormones and Development, Tianjin Key Laboratory of Metabolic Diseases, Chu Hsien-I Memorial Hospital Tianjin and Institute of Endocrinology, Tianjin Medical University, Tianjin, 300134, China
| | - Liming Chen
- NHC Key Laboratory of Hormones and Development, Tianjin Key Laboratory of Metabolic Diseases, Chu Hsien-I Memorial Hospital Tianjin and Institute of Endocrinology, Tianjin Medical University, Tianjin, 300134, China.
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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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3
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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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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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5
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Meng XX, Zhang H, Meng GL, Jiang SP, Duan XP, Wang WH, Wang MX. The effect of high-dietary K + (HK) on Kir4.1/Kir5.1 and ROMK in the distal convoluted tubule (DCT) is not affected by gender and Cl - content of the diet. Front Physiol 2022; 13:1039029. [PMID: 36439248 PMCID: PMC9682262 DOI: 10.3389/fphys.2022.1039029] [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: 09/07/2022] [Accepted: 10/27/2022] [Indexed: 11/11/2022] Open
Abstract
Basolateral potassium channels in the distal convoluted tubule (DCT) are composed of inwardly-rectifying potassium channel 4.1 (Kir4.1) and Kir5.1. Kir4.1 interacts with Kir5.1 to form a 40 pS K+ channel which is the only type K+ channel expressed in the basolateral membrane of the DCT. Moreover, Kir4.1/Kir5.1 heterotetramer plays a key role in determining the expression and activity of thiazide-sensitive Na-Cl cotransport (NCC). In addition to Kir4.1/Kir5.1, Kir1.1 (ROMK) is expressed in the apical membrane of the late DCT (DCT2) and plays a key role in mediating epithelial Na+ channel (ENaC)-dependent K+ excretion. High dietary-K+-intake (HK) stimulates ROMK and inhibits Kir4.1/Kir5.1 in the DCT. Inhibition of Kir4.1/Kir5.1 is essential for HK-induced suppression of NCC whereas the stimulation of ROMK is important for increasing ENaC-dependent K+ excretion during HK. We have now used the patch-clamp-technique to examine whether gender and Cl- content of K+-diet affect HK-induced inhibition of basolateral Kir4.1/Kir5.1 and HK-induced stimulation of ROMK. Single-channel-recording shows that basolateral 40 pS K+ channel (Kir4.1/Kir5.1) activity of the DCT defined by NPo was 1.34 (1% KCl, normal K, NK), 0.95 (5% KCl) and 1.03 (5% K+-citrate) in male mice while it was 1.47, 1.02 and 1.05 in female mice. The whole-cell recording shows that Kir4.1/Kir5.1-mediated-K+ current of the early-DCT (DCT1) was 1,170 pA (NK), 725 pA (5% KCl) and 700 pA (5% K+-citrate) in male mice whereas it was 1,125 pA, 674 pA and 700 pA in female mice. Moreover, K+-currents (IK) reversal potential of DCT (an index of membrane potential) was -63 mV (NK), -49 mV (5% KCl) and -49 mV (5% K-citrate) in the male mice whereas it was -63 mV, -50 mV and -50 mV in female mice. Finally, TPNQ-sensitive whole-cell ROMK-currents in the DCT2 /initial-connecting tubule (CNT) were 910 pA (NK), 1,520 pA (5% KCl) and 1,540 pA (5% K+-citrate) in male mice whereas the ROMK-mediated K+ currents were 1,005 pA, 1,590 pA and 1,570 pA in female mice. We conclude that the effect of HK intake on Kir4.1/Kir5.1 of the DCT and ROMK of DCT2/CNT is similar between male and female mice. Also, Cl- content in HK diets has no effect on HK-induced inhibition of Kir4.1/Kir5.1 of the DCT and HK-induced stimulation of ROMK in DCT2/CNT.
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Affiliation(s)
- Xin-Xin Meng
- Department of Physiology, Zhuhai Campus of Zunyi Medical University, Zhuhai, China
| | - Hao Zhang
- Department of Physiology, Zhuhai Campus of Zunyi Medical University, Zhuhai, China
| | - Gui-Lin Meng
- Department of Physiology, Zhuhai Campus of Zunyi Medical University, Zhuhai, China
| | - Shao-Peng Jiang
- Department of Physiology, Zhuhai Campus of Zunyi Medical University, Zhuhai, China
| | - Xin-Peng Duan
- Department of Pharmacology, New York Medical College, Valhalla, NY, United States
| | - Wen-Hui Wang
- Department of Pharmacology, New York Medical College, Valhalla, NY, United States,*Correspondence: Ming-Xiao Wang, ; Wen-Hui Wang,
| | - Ming-Xiao Wang
- Department of Physiology, Zhuhai Campus of Zunyi Medical University, Zhuhai, China,*Correspondence: Ming-Xiao Wang, ; Wen-Hui Wang,
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6
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Rosenbaek LL, Petrillo F, van Bemmelen MX, Staub O, Murali SK, Fenton RA. The E3 ubiquitin-protein ligase Nedd4-2 regulates the sodium chloride cotransporter NCC but is not required for a potassium-induced reduction of NCC expression. Front Physiol 2022; 13:971251. [PMID: 36160843 PMCID: PMC9490057 DOI: 10.3389/fphys.2022.971251] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Accepted: 08/18/2022] [Indexed: 11/21/2022] Open
Abstract
Na+ and K+ balance is influenced by the activity of the sodium chloride cotransporter NCC in the distal convoluted tubule. NCC activity and abundance are reduced by high extracellular K+. The E3 ubiquitin ligase neural precursor cell expressed developmentally downregulated 4–2 (Nedd4-2) has been proposed as a modulator of NCC abundance. Here, we examined the functional role of Nedd4-2 on NCC regulation and whether Nedd4-2 is important for the effects of high extracellular K+ on NCC. Total and plasma membrane levels of ubiquitylated NCC were lower in NCC-expressing MDCKI cells after Nedd4-2 deletion. NCC and phosphorylated NCC (pT58-NCC) levels were higher after Nedd4-2 deletion, and NCC levels on the plasma membrane were elevated. No significant changes were seen after Nedd4-2 knockdown in the levels of SPAK and phosphorylated SPAK (pS373-SPAK), the major NCC regulatory kinase. Nedd4-2 deficiency had no effect on the internalization rate of NCC from the plasma membrane, but NCC protein half-life was increased. In ex vivo experiments with kidney tubule suspensions from Nedd4-2 knockout (KO) mice, high K+ reduced total and pT58-NCC regardless of genotype. We conclude that Nedd4-2 is involved in ubiquitylation of NCC and modulating its plasma membrane levels and degradation. However, Nedd4-2 does not appear to be important for K+ induced reductions in NCC abundance.
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Affiliation(s)
- Lena L. Rosenbaek
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
- Leducq Foundation Potassium in Hypertension International Network, Massachusetts, United States
| | | | - Miguel X. van Bemmelen
- Leducq Foundation Potassium in Hypertension International Network, Massachusetts, United States
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland
| | - Olivier Staub
- Leducq Foundation Potassium in Hypertension International Network, Massachusetts, United States
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland
| | - Sathish K. Murali
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
- Leducq Foundation Potassium in Hypertension International Network, Massachusetts, United States
- Department of Biomedical Sciences, University of Veterinary Medicine, Vienna, Austria
| | - Robert A. Fenton
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
- Leducq Foundation Potassium in Hypertension International Network, Massachusetts, United States
- *Correspondence: Robert A. Fenton,
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7
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McDonough AA, Fenton RA. Potassium homeostasis: sensors, mediators, and targets. Pflugers Arch 2022; 474:853-867. [PMID: 35727363 PMCID: PMC10163916 DOI: 10.1007/s00424-022-02718-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2022] [Revised: 06/08/2022] [Accepted: 06/12/2022] [Indexed: 12/16/2022]
Abstract
Transmembrane potassium (K) gradients are key determinants of membrane potential that can modulate action potentials, control muscle contractility, and influence ion channel and transporter activity. Daily K intake is normally equal to the amount of K in the entire extracellular fluid (ECF) creating a critical challenge - how to maintain ECF [K] and membrane potential in a narrow range during feast and famine. Adaptations to maintain ECF [K] include sensing the K intake, sensing ECF [K] vs. desired set-point and activating mediators that regulate K distribution between ECF and ICF, and regulate renal K excretion. In this focused review, we discuss the basis of these adaptions, including (1) potential mechanisms for rapid feedforward signaling to kidney and muscle after a meal (before a rise in ECF [K]), (2) how skeletal muscles sense and respond to changes in ECF [K], (3) effects of K on aldosterone biosynthesis, and (4) how the kidney responds to changes in ECF [K] to modify K excretion. The concepts of sexual dimorphisms in renal K handling adaptation are introduced, and the molecular mechanisms that can account for the benefits of a K-rich diet to maintain cardiovascular health are discussed. Although the big picture of K homeostasis is becoming more clear, we also highlight significant pieces of the puzzle that remain to be solved, including knowledge gaps in our understanding of initiating signals, sensors and their connection to homeostatic adjustments of ECF [K].
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Affiliation(s)
- Alicia A McDonough
- Department of Physiology and Neuroscience, University of Southern California Keck School of Medicine, Los Angeles, CA, USA.
| | - Robert A Fenton
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
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8
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Veiras LC, Bernstein EA, Cao D, Okwan-Duodu D, Khan Z, Gibb DR, Roach A, Skelton R, Williams RM, Bernstein KE, Giani JF. Tubular IL-1β Induces Salt Sensitivity in Diabetes by Activating Renal Macrophages. Circ Res 2022; 131:59-73. [PMID: 35574842 PMCID: PMC9233055 DOI: 10.1161/circresaha.121.320239] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Chronic renal inflammation has been widely recognized as a major promoter of several forms of high blood pressure including salt-sensitive hypertension. In diabetes, IL (interleukin)-6 induces salt sensitivity through a dysregulation of the epithelial sodium channel. However, the origin of this inflammatory process and the molecular events that culminates with an abnormal regulation of epithelial sodium channel and salt sensitivity in diabetes are largely unknown. METHODS Both in vitro and in vivo approaches were used to investigate the molecular and cellular contributors to the renal inflammation associated with diabetic kidney disease and how these inflammatory components interact to develop salt sensitivity in db/db mice. RESULTS Thirty-four-week-old db/db mice display significantly higher levels of IL-1β in renal tubules compared with nondiabetic db/+ mice. Specific suppression of IL-1β in renal tubules prevented salt sensitivity in db/db mice. A primary culture of renal tubular epithelial cells from wild-type mice releases significant levels of IL-1β when exposed to a high glucose environment. Coculture of tubular epithelial cells and bone marrow-derived macrophages revealed that tubular epithelial cell-derived IL-1β promotes the polarization of macrophages towards a proinflammatory phenotype resulting in IL-6 secretion. To evaluate whether macrophages are the cellular target of IL-1β in vivo, diabetic db/db mice were transplanted with the bone marrow of IL-1R1 (IL-1 receptor type 1) knockout mice. db/db mice harboring an IL-1 receptor type 1 knockout bone marrow remained salt resistant, display lower renal inflammation and lower expression and activity of epithelial sodium channel compared with db/db transplanted with a wild-type bone marrow. CONCLUSIONS Renal tubular epithelial cell-derived IL-1β polarizes renal macrophages towards a proinflammatory phenotype that promotes salt sensitivity through the accumulation of renal IL-6. When tubular IL-1β synthesis is suppressed or in db/db mice in which immune cells lack the IL-1R1, macrophage polarization is blunted resulting in no salt-sensitive hypertension.
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Affiliation(s)
- Luciana C Veiras
- Department of Biomedical Sciences (L.C.V., E.A.B., D.C., Z.K., K.E.B., J.F.G.), Cedars-Sinai Medical Center, Los Angeles, CA
| | - Ellen A Bernstein
- Department of Biomedical Sciences (L.C.V., E.A.B., D.C., Z.K., K.E.B., J.F.G.), Cedars-Sinai Medical Center, Los Angeles, CA
| | - DuoYao Cao
- Department of Biomedical Sciences (L.C.V., E.A.B., D.C., Z.K., K.E.B., J.F.G.), Cedars-Sinai Medical Center, Los Angeles, CA
| | | | - Zakir Khan
- Department of Biomedical Sciences (L.C.V., E.A.B., D.C., Z.K., K.E.B., J.F.G.), Cedars-Sinai Medical Center, Los Angeles, CA
- Department of Pathology and Laboratory Medicine (Z.K., D.R.G., K.E.B., J.F.G.), Cedars-Sinai Medical Center, Los Angeles, CA
| | - David R Gibb
- Department of Pathology and Laboratory Medicine (Z.K., D.R.G., K.E.B., J.F.G.), Cedars-Sinai Medical Center, Los Angeles, CA
| | - Arantxa Roach
- Department of Biomedical Engineering, The City College of New York' New York' NY (A.R., R.S., R.M.W.)
| | - Rachel Skelton
- Department of Biomedical Engineering, The City College of New York' New York' NY (A.R., R.S., R.M.W.)
| | - Ryan M Williams
- Department of Biomedical Engineering, The City College of New York' New York' NY (A.R., R.S., R.M.W.)
| | - Kenneth E Bernstein
- Department of Biomedical Sciences (L.C.V., E.A.B., D.C., Z.K., K.E.B., J.F.G.), Cedars-Sinai Medical Center, Los Angeles, CA
- Department of Pathology and Laboratory Medicine (Z.K., D.R.G., K.E.B., J.F.G.), Cedars-Sinai Medical Center, Los Angeles, CA
| | - Jorge F Giani
- Department of Biomedical Sciences (L.C.V., E.A.B., D.C., Z.K., K.E.B., J.F.G.), Cedars-Sinai Medical Center, Los Angeles, CA
- Department of Pathology and Laboratory Medicine (Z.K., D.R.G., K.E.B., J.F.G.), Cedars-Sinai Medical Center, Los Angeles, CA
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9
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Al‐Qusairi L, Basquin D, Stifanelli M, Welling PA, Staub O. Does the early aldosterone-induced SGK1 play a role in early Kaliuresis? Physiol Rep 2022; 10:e15188. [PMID: 35224872 PMCID: PMC8883148 DOI: 10.14814/phy2.15188] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Revised: 12/30/2021] [Accepted: 12/30/2021] [Indexed: 06/14/2023] Open
Abstract
Urinary K+ potassium excretion rapidly increases after a potassium-rich meal. The early aldosterone-induced sgk1 gene (encoding serum and glucocorticoid-induced kinase 1), activates potassium clearance, but the role of this kinase in the early activation of K+ secretion has not been clearly defined. Here, we challenged inducible renal-tubule-specific Sgk1Pax8 / LC1 knockout mice with an acute high-potassium load (HK:5%K+ ) and compared the physiological and molecular responses to control mice. We observe that urinary excretion after a K+ load over the first 3 h is not dependent on SGK1 but is coincident with the rapid dephosphorylation of the Na+ ,Cl- -cotransporter (NCC) to increase distal salt delivery. Molecular analyses indicate that whereas SGK1-mediated phosphorylation of the ubiquitin-protein ligase NEDD4-2 begins to increase by 3h, SGK1-dependent proteolytic activation of ENaC only becomes detectable after 6 h of HK intake. Consistent with SGK1-dependent ENaC activation via inhibition of NEDD4-2-mediated ubiquitylation, Sgk1Pax8 / LC1 mice are unable to efficiently inhibit NEDD4-2 or increase ENaC cleavage after 6 h of HK. Nevertheless, no defect in acute K+ balance was detected in the mutant mice after 6 h of HK. Moreover, we found that Sgk1Pax8 / LC1 mice reduce NCC phosphorylation and NCC-mediated salt absorption to a greater extent than control mice after a K+ load, promoting increased amiloride-sensitive Na+ -reabsorption via ENaC to maintain adequate kaliuresis. Together, these data indicate that: (a) during the early 3 h of HK intake, K+ excretion is SGK1-independent even under an extreme K+ challenge, (b) shortly after, SGK1 inhibits NEDD4-2 and activates ENaC to stimulate K+ -secretion, (c) SGK1-dependent phosphorylation of NCC occurs, acting more likely as a brake pedal to prevent excessive K+ loss.
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Affiliation(s)
- Lama Al‐Qusairi
- Division of NephrologyJohns Hopkins University School of MedicineBaltimoreUSA
- Department of Biomedical SciencesUniversity of LausanneLausanneSwitzerland
| | - Denis Basquin
- Department of PhysiologyUniversity of MarylandBaltimoreUSA
- Department of Biomedical SciencesUniversity of LausanneLausanneSwitzerland
| | - Matteo Stifanelli
- Department of Biomedical SciencesUniversity of LausanneLausanneSwitzerland
| | - Paul A. Welling
- Division of NephrologyJohns Hopkins University School of MedicineBaltimoreUSA
| | - Olivier Staub
- Department of Biomedical SciencesUniversity of LausanneLausanneSwitzerland
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10
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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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11
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Zhang DD, Zheng JY, Duan XP, Lin DH, Wang WH. ROMK channels are inhibited in the aldosterone-sensitive distal nephron of renal tubule Nedd4-2-deficient mice. Am J Physiol Renal Physiol 2022; 322:F55-F67. [PMID: 34843409 PMCID: PMC8714254 DOI: 10.1152/ajprenal.00306.2021] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 11/18/2021] [Accepted: 11/27/2021] [Indexed: 01/03/2023] Open
Abstract
We used whole cell recording to examine the renal outer medullary K+ channel (ROMK or Kir1.1) and epithelial Na+ channel (ENaC) in the late distal convoluted tubule (DCT2)/initial connecting tubule (iCNT) and in the cortical collecting duct (CCD) of kidney tubule-specific neural precursor cell-expressed developmentally downregulated protein 4-2 (Nedd4-2) knockout mice (Ks-Nedd4-2 KO) and floxed neural precursor cell-expressed developmentally downregulated 4-like (Nedd4l) mice (control). Tertiapin Q (TPNQ)-sensitive K+ currents (ROMK) were smaller in both the DCT2/iCNT and CCD of Ks-Nedd4-2 KO mice on a normal diet than in control mice. Neither high dietary salt intake nor low dietary salt intake had a significant effect on ROMK activity in the DCT2/iCNT and CCD of control and Ks-Nedd4-2 KO mice. In contrast, high dietary K+ intake (HK) increased, whereas low dietary K+ intake (LK) decreased TPNQ-sensitive K+ currents in floxed Nedd4l mice. However, the effects of dietary K+ intake on ROMK channel activity were absent in Ks-Nedd4-2 KO mice since neither HK nor LK significantly affected TPNQ-sensitive K+ currents in the DCT2/iCNT and CCD. Moreover, TPNQ-sensitive K+ currents in the DCT2/iCNT and CCD of Ks-Nedd4-2 KO mice on HK were similar to those of control mice on LK. Amiloride-sensitive Na+ currents in the DCT2/iCNT and CCD were significantly higher in Ks-Nedd4-2 KO mice than in floxed Nedd4l mice on a normal K+ diet. HK increased ENaC activity of the DCT2/iCNT only in control mice, but HK stimulated ENaC of the CCD in both control and Ks-Nedd4-2 KO mice. Moreover, the HK-induced increase in amiloride-sensitive Na+ currents was larger in Ks-Nedd4-2 KO mice than in control mice. Deletion of Nedd4-2 increased with no lysine kinase 1 expression and abolished HK-induced inhibition of with no lysine kinase 1. We conclude that deletion of Nedd4-2 increases ENaC activity but decreases ROMK activity in the aldosterone-sensitive distal nephron and that HK fails to stimulate ROMK, but robustly increases ENaC activity in the CCD of Nedd4-2-deficient mice.NEW & NOTEWORTHY We demonstrate that renal outer medullary K+ (ROMK) channel activity is inhibited in the late distal convoluted tubule/initial connecting tubule and cortical collecting duct of neural precursor cell-expressed developmentally downregulated protein 4-2 (Nedd4-2)-deficient mice. Also, deletion of Nedd4-2 abolishes the stimulatory effect of dietary K+ intake on ROMK. The lack of high K+-induced stimulation of ROMK is associated with the absence of high K+-induced inhibition of with no lysine kinase 1.
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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, Guangdong, China
- Department of Pharmacology, New York Medical College, Valhalla, New York
| | - Jun-Ya Zheng
- Department of Endocrinology, First Affiliated Hospital of Harbin Medical University, Harbin, 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
| | - Dao-Hong Lin
- 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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12
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Isaeva E, Bohovyk R, Fedoriuk M, Shalygin A, Klemens CA, Zietara A, Levchenko V, Denton JS, Staruschenko A, Palygin O. Crosstalk between ENaC and basolateral K ir 4.1/K ir 5.1 channels in the cortical collecting duct. Br J Pharmacol 2021; 179:2953-2968. [PMID: 34904226 DOI: 10.1111/bph.15779] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Revised: 10/06/2021] [Accepted: 12/06/2021] [Indexed: 11/02/2022] Open
Abstract
BACKGROUND AND PURPOSE Inwardly rectifying K+ (Kir ) channels located on the basolateral membrane of epithelial cells of the distal nephron play a crucial role in K+ handling and blood pressure control, making these channels an attractive target for the treatment of hypertension. The purpose of the present study was to determine how the inhibition of basolateral Kir 4.1/Kir 5.1 heteromeric K+ channel affects epithelial sodium channel (ENaC)-mediated Na+ transport in the principal cells of cortical collecting duct (CCD). EXPERIMENTAL APPROACH The effect of fluoxetine, amitriptyline, and recently developed Kir inhibitor, VU0134992, on the activity of Kir 4.1, Kir 4.1/Kir 5.1, and ENaC were tested using electrophysiological approaches in Chinese hamster ovary (CHO) cells transfected with respective channel subunits, cultured polarized epithelial mCCDcl1 cells, and freshly isolated rat and human CCD tubules. To test the effect of pharmacological Kir 4.1/Kir 5.1 inhibition on electrolyte homeostasis in vivo and corresponding changes in distal tubule transport, Dahl salt-sensitive rats were injected with amitriptyline (15 mg kg-1 day-1 ) for three days. KEY RESULTS We found that inhibition of Kir 4.1/Kir 5.1, but not Kir 4.1 channel, depolarizes cell membrane, induces the elevation of intracellular Ca2+ concentration, and suppresses ENaC activity. Furthermore, we demonstrate that amitriptyline administration leads to a significant drop in plasma K+ level, triggering sodium excretion and diuresis. CONCLUSION AND IMPLICATIONS Present data uncovers a specific role of the Kir 4.1/Kir 5.1 channel in the modulation of ENaC activity and emphasizes the potential for using Kir 4.1/Kir 5.1 inhibitors to regulate electrolyte homeostasis and blood pressure.
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Affiliation(s)
- Elena Isaeva
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, USA.,Department of Cellular Membranology, Bogomoletz Institute of Physiology, Kyiv, Ukraine
| | - Ruslan Bohovyk
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, USA.,Department of Cellular Membranology, Bogomoletz Institute of Physiology, Kyiv, Ukraine.,Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, FL, USA
| | - Mykhailo Fedoriuk
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, USA.,Department of Cellular Membranology, Bogomoletz Institute of Physiology, Kyiv, Ukraine
| | - Alexey Shalygin
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, USA.,Institute of Cytology of the Russian Academy of Sciences, St. Petersburg, Russia
| | - Christine A Klemens
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, USA.,Cardiovascular Center, Medical College of Wisconsin, Milwaukee, WI, USA.,Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, FL, USA
| | - Adrian Zietara
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, USA.,Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, FL, USA
| | - Vladislav Levchenko
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, USA.,Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, FL, USA
| | - Jerod S Denton
- Department of Anesthesiology and Pharmacology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Alexander Staruschenko
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, USA.,Cardiovascular Center, Medical College of Wisconsin, Milwaukee, WI, USA.,Clement J. Zablocki VA Medical Center, Milwaukee, WI, USA.,Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, FL, USA
| | - Oleg Palygin
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, USA.,Department of Medicine, Division of Nephrology, Medical University of South Carolina, Charleston, SC, USA
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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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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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15
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Franken GAC, Adella A, Bindels RJM, de Baaij JHF. Mechanisms coupling sodium and magnesium reabsorption in the distal convoluted tubule of the kidney. Acta Physiol (Oxf) 2021; 231:e13528. [PMID: 32603001 PMCID: PMC7816272 DOI: 10.1111/apha.13528] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Revised: 05/29/2020] [Accepted: 06/22/2020] [Indexed: 02/06/2023]
Abstract
Hypomagnesaemia is a common feature of renal Na+ wasting disorders such as Gitelman and EAST/SeSAME syndrome. These genetic defects specifically affect Na+ reabsorption in the distal convoluted tubule, where Mg2+ reabsorption is tightly regulated. Apical uptake via TRPM6 Mg2+ channels and basolateral Mg2+ extrusion via a putative Na+ -Mg2+ exchanger determines Mg2+ reabsorption in the distal convoluted tubule. However, the mechanisms that explain the high incidence of hypomagnesaemia in patients with Na+ wasting disorders of the distal convoluted tubule are largely unknown. In this review, we describe three potential mechanisms by which Mg2+ reabsorption in the distal convoluted tubule is linked to Na+ reabsorption. First, decreased activity of the thiazide-sensitive Na+ /Cl- cotransporter (NCC) results in shortening of the segment, reducing the Mg2+ reabsorption capacity. Second, the activity of TRPM6 and NCC are determined by common regulatory pathways. Secondary effects of NCC dysregulation such as hormonal imbalance, therefore, might disturb TRPM6 expression. Third, the basolateral membrane potential, maintained by the K+ permeability and Na+ -K+ -ATPase activity, provides the driving force for Na+ and Mg2+ extrusion. Depolarisation of the basolateral membrane potential in Na+ wasting disorders of the distal convoluted tubule may therefore lead to reduced activity of the putative Na+ -Mg2+ exchanger SLC41A1. Elucidating the interconnections between Mg2+ and Na+ transport in the distal convoluted tubule is hampered by the currently available models. Our analysis indicates that the coupling of Na+ and Mg2+ reabsorption may be multifactorial and that advanced experimental models are required to study the molecular mechanisms.
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Affiliation(s)
- Gijs A. C. Franken
- Department of PhysiologyRadboud Institute for Molecular Life SciencesRadboud University Medical CenterNijmegenthe Netherlands
| | - Anastasia Adella
- Department of PhysiologyRadboud Institute for Molecular Life SciencesRadboud University Medical CenterNijmegenthe Netherlands
| | - René J. M. Bindels
- Department of PhysiologyRadboud Institute for Molecular Life SciencesRadboud University Medical CenterNijmegenthe Netherlands
| | - Jeroen H. F. de Baaij
- Department of PhysiologyRadboud Institute for Molecular Life SciencesRadboud University Medical CenterNijmegenthe Netherlands
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16
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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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Yamazaki O, Hirohama D, Ishizawa K, Shibata S. Role of the Ubiquitin Proteasome System in the Regulation of Blood Pressure: A Review. Int J Mol Sci 2020; 21:E5358. [PMID: 32731518 PMCID: PMC7432568 DOI: 10.3390/ijms21155358] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 07/24/2020] [Accepted: 07/24/2020] [Indexed: 12/18/2022] Open
Abstract
The kidney and the vasculature play crucial roles in regulating blood pressure. The ubiquitin proteasome system (UPS), a multienzyme process mediating covalent conjugation of the 76-amino acid polypeptide ubiquitin to a substrate protein followed by proteasomal degradation, is involved in multiple cellular processes by regulating protein turnover in various tissues. Increasing evidence demonstrates the roles of UPS in blood pressure regulation. In the kidney, filtered sodium is reabsorbed through diverse sodium transporters and channels along renal tubules, and studies conducted till date have provided insights into the complex molecular network through which ubiquitin ligases modulate sodium transport in different segments. Components of these pathways include ubiquitin ligase neuronal precursor cell-expressed developmentally downregulated 4-2, Cullin-3, and Kelch-like 3. Moreover, accumulating data indicate the roles of UPS in blood vessels, where it modulates nitric oxide bioavailability and vasoconstriction. Cullin-3 not only regulates renal salt reabsorption but also controls vascular tone using different adaptor proteins that target distinct substrates in vascular smooth muscle cells. In endothelial cells, UPS can also contribute to blood pressure regulation by modulating endothelial nitric oxide synthase. In this review, we summarize current knowledge regarding the role of UPS in blood pressure regulation, focusing on renal sodium reabsorption and vascular function.
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Affiliation(s)
| | | | | | - Shigeru Shibata
- Division of Nephrology, Department of Internal Medicine, Teikyo University School of Medicine, Tokyo 173-8605, Japan; (O.Y.); (D.H.); (K.I.)
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