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Gao Y, Cao F, Tian X, Zhang Q, Xu C, Ji B, Zhang YA, Du L, Han J, Li L, Zhou S, Gong Y, Ying B, Gao-Smith F, Jin S. Inhibition the ubiquitination of ENaC and Na,K-ATPase with erythropoietin promotes alveolar fluid clearance in sepsis-induced acute respiratory distress syndrome. Biomed Pharmacother 2024; 174:116447. [PMID: 38518606 DOI: 10.1016/j.biopha.2024.116447] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2024] [Revised: 03/08/2024] [Accepted: 03/15/2024] [Indexed: 03/24/2024] Open
Abstract
Sepsis-induced acute respiratory distress syndrome (ARDS) causes significant fatalities worldwide and lacks pharmacological intervention. Alveolar fluid clearance (AFC) plays a pivotal role in the remission of ARDS and is markedly impaired in the pathogenesis of ARDS. Here, we demonstrated that erythropoietin could effectively ameliorate lung injury manifestations and lethality, restore lung function and promote AFC in a rat model of lipopolysaccharide (LPS)-induced ARDS. Moreover, it was proven that EPO-induced restoration of AFC occurs through triggering the total protein expression of ENaC and Na,K-ATPase channels, enhancing their protein abundance in the membrane, and suppressing their ubiquitination for degeneration. Mechanistically, the data indicated the possible involvement of EPOR/JAK2/STAT3/SGK1/Nedd4-2 signaling in this process, and the pharmacological inhibition of the pathway markedly eliminated the stimulating effects of EPO on ENaC and Na,K-ATPase, and subsequently reversed the augmentation of AFC by EPO. Consistently, in vitro studies of alveolar epithelial cells paralleled with that EPO upregulated the expression of ENaC and Na,K-ATPase, and patch-clamp studies further demonstrated that EPO substantially strengthened sodium ion currents. Collectively, EPO could effectively promote AFC by improving ENaC and Na,K-ATPase protein expression and abundance in the membrane, dependent on inhibition of ENaC and Na,K-ATPase ubiquitination, and resulting in diminishing LPS-associated lung injuries.
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Affiliation(s)
- Ye Gao
- Department of Anaesthesia, Pain and Critical Care, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China; Key Laboratory of Pediatric Anesthesiology, Ministry of Education, Wenzhou Medical University, Zhejiang, China; Laboratory of Anesthesiology of Zhejiang Province, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Zhejiang, China
| | - Fei Cao
- Department of Anaesthesia, Pain and Critical Care, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China; Key Laboratory of Pediatric Anesthesiology, Ministry of Education, Wenzhou Medical University, Zhejiang, China; Laboratory of Anesthesiology of Zhejiang Province, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Zhejiang, China; Department of Anesthesiology, Sun Yat-sen University Cancer Center, Guangzhou, China
| | - Xinyi Tian
- Department of Anaesthesia, Pain and Critical Care, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China; Key Laboratory of Pediatric Anesthesiology, Ministry of Education, Wenzhou Medical University, Zhejiang, China; Laboratory of Anesthesiology of Zhejiang Province, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Zhejiang, China
| | - Qianping Zhang
- Department of Anaesthesia, Pain and Critical Care, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Congcong Xu
- Department of Anaesthesia, Pain and Critical Care, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China; Key Laboratory of Pediatric Anesthesiology, Ministry of Education, Wenzhou Medical University, Zhejiang, China; Laboratory of Anesthesiology of Zhejiang Province, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Zhejiang, China
| | - Bowen Ji
- Department of Anaesthesia, Pain and Critical Care, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China; Key Laboratory of Pediatric Anesthesiology, Ministry of Education, Wenzhou Medical University, Zhejiang, China; Laboratory of Anesthesiology of Zhejiang Province, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Zhejiang, China
| | - Ye-An Zhang
- Department of Anaesthesia, Pain and Critical Care, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China; Key Laboratory of Pediatric Anesthesiology, Ministry of Education, Wenzhou Medical University, Zhejiang, China; Laboratory of Anesthesiology of Zhejiang Province, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Zhejiang, China
| | - Linan Du
- Department of Anaesthesia, Pain and Critical Care, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China; Key Laboratory of Pediatric Anesthesiology, Ministry of Education, Wenzhou Medical University, Zhejiang, China; Laboratory of Anesthesiology of Zhejiang Province, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Zhejiang, China
| | - Jun Han
- Department of Anaesthesia, Pain and Critical Care, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China; Key Laboratory of Pediatric Anesthesiology, Ministry of Education, Wenzhou Medical University, Zhejiang, China; Laboratory of Anesthesiology of Zhejiang Province, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Zhejiang, China
| | - Li Li
- Department of Anaesthesia, Pain and Critical Care, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China; Key Laboratory of Pediatric Anesthesiology, Ministry of Education, Wenzhou Medical University, Zhejiang, China; Laboratory of Anesthesiology of Zhejiang Province, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Zhejiang, China
| | - Siyu Zhou
- Department of Anaesthesia, Pain and Critical Care, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China; Key Laboratory of Pediatric Anesthesiology, Ministry of Education, Wenzhou Medical University, Zhejiang, China; Laboratory of Anesthesiology of Zhejiang Province, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Zhejiang, China
| | - Yuqiang Gong
- Department of Anaesthesia, Pain and Critical Care, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China; Key Laboratory of Pediatric Anesthesiology, Ministry of Education, Wenzhou Medical University, Zhejiang, China; Laboratory of Anesthesiology of Zhejiang Province, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Zhejiang, China
| | - Binyu Ying
- Department of Anaesthesia, Pain and Critical Care, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China; Key Laboratory of Pediatric Anesthesiology, Ministry of Education, Wenzhou Medical University, Zhejiang, China; Laboratory of Anesthesiology of Zhejiang Province, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Zhejiang, China
| | - Fang Gao-Smith
- Department of Anaesthesia, Pain and Critical Care, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China; Key Laboratory of Pediatric Anesthesiology, Ministry of Education, Wenzhou Medical University, Zhejiang, China; Laboratory of Anesthesiology of Zhejiang Province, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Zhejiang, China; Centre for Translational Inflammation Research, Institute of Inflammation and Aging, University of Birmingham, Birmingham, United Kingdom.
| | - Shengwei Jin
- Department of Anaesthesia, Pain and Critical Care, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China; Key Laboratory of Pediatric Anesthesiology, Ministry of Education, Wenzhou Medical University, Zhejiang, China; Laboratory of Anesthesiology of Zhejiang Province, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Zhejiang, China.
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Liu Y, Yang H, Zeng R, He L, Xiao T, Peng X, Kuang Z, Wu L. NEDD4-2 and the CLC-2 channel regulate neuronal excitability in the pathogenesis of mesial temporal lobe epilepsy. Sci Rep 2024; 14:4835. [PMID: 38418461 PMCID: PMC10902323 DOI: 10.1038/s41598-024-52399-4] [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: 10/06/2023] [Accepted: 01/18/2024] [Indexed: 03/01/2024] Open
Abstract
An increasing number of studies have focused on the role of NEDD4-2 in regulating neuronal excitability and the mechanism of epilepsy. However, the exact mechanism has not yet been elucidated. Here, we explored the roles of NEDD4-2 and the CLC-2 channel in regulating neuronal excitability and mesial temporal lobe epilepsy (MTLE) pathogenesis. First, chronic MTLE models were induced by lithium-pilocarpine in developmental rats. Coimmunoprecipitation analysis revealed that the interaction between CLC-2 and NEDD4-2. Western blot analyses indicated that NEDD4-2 expression was downregulated, while phosphorylated (P-) NEDD4-2 and CLC-2 expression was upregulated in adult MTLE rats. Then, the primary hippocampal neuronal cells were isolated and cultured, and the NEDD4-2 was knocked down by shRNA vector, resulting in decreased protein levels of CLC-2. While CLC-2 absence caused increased NEDD4-2 in cells. Next, in an epileptic cell model induced by a Mg2+-free culture, whole-cell current-clamp recording demonstrated that NEDD4-2 deficiency inhibited the spontaneous action potentials of cells, and CLC-2 absence caused more significant decrease in the spontaneous action potentials of cells. In conclusion, we herein revealed that NEDD4-2 regulates the expression of CLC-2, which is involved in neuronal excitability, and participates in the pathogenesis of MTLE.
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Affiliation(s)
- Yuting Liu
- Pediatrics Research Institute of Hunan Province, Hunan Children's Hospital, Changsha, Hunan, China
| | - Haiyan Yang
- Department of Neurology, Hunan Children's Hospital, Changsha, 410008, Hunan, China
| | - Rongrong Zeng
- Department of Neurology, Hunan Children's Hospital, Changsha, 410008, Hunan, China
| | - Lu He
- Department of Neurology, Hunan Children's Hospital, Changsha, 410008, Hunan, China
| | - Ting Xiao
- Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Xiaomei Peng
- Department of Neurology, Hunan Children's Hospital, Changsha, 410008, Hunan, China
| | - Zhuo Kuang
- Department of Neurology, Hunan Children's Hospital, Changsha, 410008, Hunan, China
| | - Liwen Wu
- Department of Neurology, Hunan Children's Hospital, Changsha, 410008, Hunan, China.
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Teafatiller T, Perez O, Kitazawa M, Agrawal A, Subramanian VS. Nedd4-1 regulates human sodium-dependent vitamin C transporter-2 functional expression in neuronal and epithelial cells. J Nutr Biochem 2023; 120:109413. [PMID: 37423323 DOI: 10.1016/j.jnutbio.2023.109413] [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: 05/12/2023] [Revised: 06/12/2023] [Accepted: 07/05/2023] [Indexed: 07/11/2023]
Abstract
The ubiquitin-proteasomal pathway regulates the functional expression of many membrane transporters in a variety of cellular systems. Nothing is currently known about the role of ubiquitin E3 ligase, neural precursor cell-expressed developmentally down-regulated gene 4 (Nedd4-1) and the proteasomal degradation pathway in regulating human vitamin C transporter-2 (hSVCT2) in neuronal cells. hSVCT2 mediates the uptake of ascorbic acid (AA) and is the predominantly expressed vitamin C transporter isoform in neuronal systems. Therefore, we addressed this knowledge gap in our study. Analysis of mRNA revealed markedly higher expression of Nedd4-1 in neuronal samples than that of Nedd4-2. Interestingly, Nedd4-1 expression in the hippocampus was higher in patients with Alzheimer's disease (AD) and age-dependently increased in the J20 mouse model of AD. The interaction of Nedd4-1 and hSVCT2 was confirmed by coimmunoprecipitation and colocalization. While the coexpression of Nedd4-1 with hSVCT2 displayed a significant decrease in AA uptake, siRNA-mediated knockdown of Nedd4-1 expression up-regulated the AA uptake. Further, we mutated a classical Nedd4 protein interacting motif ("PPXY") within the hSVCT2 polypeptide and observed markedly decreased AA uptake due to the intracellular localization of the mutated hSVCT2. Also, we determined the role of the proteasomal degradation pathway in hSVCT2 functional expression in SH-SY5Y cells and the results indicated that the proteasomal inhibitor (MG132) significantly up-regulated the AA uptake and hSVCT2 protein expression level. Taken together, our findings show that the regulation of hSVCT2 functional expression is at least partly mediated by the Nedd4-1 dependent ubiquitination and proteasomal pathways.
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Affiliation(s)
- Trevor Teafatiller
- Department of Medicine, University of California, Irvine, California, USA
| | - Oasis Perez
- Department of Medicine, University of California, Irvine, California, USA
| | - Masashi Kitazawa
- Department of Environmental and Occupational Health, University of California, Irvine, California, USA
| | - Anshu Agrawal
- Department of Medicine, University of California, Irvine, California, USA
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Weldemariam MM, Woo J, Zhang Q. Pancreatic INS-1 β-Cell Response to Thapsigargin and Rotenone: A Comparative Proteomics Analysis Uncovers Key Pathways of β-Cell Dysfunction. Chem Res Toxicol 2022; 35:1080-1094. [PMID: 35544339 DOI: 10.1021/acs.chemrestox.2c00058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Insulin-secreting β-cells in the pancreatic islets are exposed to various endogenous and exogenous stressing conditions, which may lead to β-cell dysfunction or apoptosis and ultimately to diabetes mellitus. However, the detailed molecular mechanisms underlying β-cell's inability to survive under severe stresses remain to be explored. This study used two common chemical stressors, thapsigargin and rotenone, to induce endoplasmic reticulum (ER) and mitochondria stress in a rat insuloma INS-1 832/13 β-cell line, mimicking the conditions experienced by dysfunctional β-cells. Proteomic changes of cells upon treatment with stressors at IC50 were profiled with TMT-based quantitative proteomics and further verified using label-free quantitive proteomics. The differentially expressed proteins under stress conditions were selected for in-depth bioinformatic analysis. Thapsigargin treatment specifically perturbed unfolded protein response (UPR) related pathways; in addition, 58 proteins not previously linked to the UPR related pathways were identified with consistent upregulation under stress induced by thapsigargin. Conversely, rotenone treatment resulted in significant proteome changes in key mitochondria regulatory pathways such as fatty acid β-oxidation, cellular respiration, citric acid cycle, and respiratory electron transport. Our data also demonstrated that both stressors increased reactive oxygen species production and depleted adenosine triphosphate synthesis, resulting in significant dysregulation of oxidative phosphorylation signaling pathways. These novel dysregulated proteins may suggest an alternative mechanism of action in β-cell dysfunction and provide potential targets for probing ER- and mitochondria stress-induced β-cell death.
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Affiliation(s)
- Mehari Muuz Weldemariam
- Center for Translational Biomedical Research, University of North Carolina at Greensboro, North Carolina Research Campus, Kannapolis, North Carolina 28081, United States
| | - Jongmin Woo
- Center for Translational Biomedical Research, University of North Carolina at Greensboro, North Carolina Research Campus, Kannapolis, North Carolina 28081, United States
| | - Qibin Zhang
- Center for Translational Biomedical Research, University of North Carolina at Greensboro, North Carolina Research Campus, Kannapolis, North Carolina 28081, United States.,Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro, North Carolina 27402, United States
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5
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Pearce D, Manis AD, Nesterov V, Korbmacher C. Regulation of distal tubule sodium transport: mechanisms and roles in homeostasis and pathophysiology. Pflugers Arch 2022; 474:869-884. [PMID: 35895103 PMCID: PMC9338908 DOI: 10.1007/s00424-022-02732-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Revised: 07/09/2022] [Accepted: 07/11/2022] [Indexed: 02/03/2023]
Abstract
Regulated Na+ transport in the distal nephron is of fundamental importance to fluid and electrolyte homeostasis. Further upstream, Na+ is the principal driver of secondary active transport of numerous organic and inorganic solutes. In the distal nephron, Na+ continues to play a central role in controlling the body levels and concentrations of a more select group of ions, including K+, Ca++, Mg++, Cl-, and HCO3-, as well as water. Also, of paramount importance are transport mechanisms aimed at controlling the total level of Na+ itself in the body, as well as its concentrations in intracellular and extracellular compartments. Over the last several decades, the transporters involved in moving Na+ in the distal nephron, and directly or indirectly coupling its movement to that of other ions have been identified, and their interrelationships brought into focus. Just as importantly, the signaling systems and their components-kinases, ubiquitin ligases, phosphatases, transcription factors, and others-have also been identified and many of their actions elucidated. This review will touch on selected aspects of ion transport regulation, and its impact on fluid and electrolyte homeostasis. A particular focus will be on emerging evidence for site-specific regulation of the epithelial sodium channel (ENaC) and its role in both Na+ and K+ homeostasis. In this context, the critical regulatory roles of aldosterone, the mineralocorticoid receptor (MR), and the kinases SGK1 and mTORC2 will be highlighted. This includes a discussion of the newly established concept that local K+ concentrations are involved in the reciprocal regulation of Na+-Cl- cotransporter (NCC) and ENaC activity to adjust renal K+ secretion to dietary intake.
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Affiliation(s)
- David Pearce
- Department of Medicine, Division of Nephrology, and Department of Cellular and Molecular Pharmacology, University of California San Francisco, San Francisco, CA USA
| | - Anna D. Manis
- Department of Medicine, Division of Nephrology, and Department of Cellular and Molecular Pharmacology, University of California San Francisco, San Francisco, CA USA
| | - Viatcheslav Nesterov
- Institut für Zelluläre und Molekulare Physiologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany, Erlangen, Germany
| | - Christoph Korbmacher
- Institut für Zelluläre und Molekulare Physiologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany, Erlangen, Germany
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Shi S, Buck TM, Nickerson AJ, Brodsky JL, Kleyman TR. Paraoxonase 2 is an ER chaperone that regulates the epithelial Na + channel. Am J Physiol Cell Physiol 2022; 322:C111-C121. [PMID: 34852210 PMCID: PMC8759969 DOI: 10.1152/ajpcell.00335.2021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The mammalian paraoxonases (PONs) have been linked to protection against oxidative stress. However, the physiological roles of members in this family (PON1, PON2, and PON3) are still being characterized. PON2 and PON3 are expressed in the aldosterone-sensitive distal nephron of the kidney and have been shown to negatively regulate expression of the epithelial sodium channel (ENaC), a trimeric ion channel that orchestrates salt and water homeostasis. To date, the nature of this phenomenon has not been explored. Therefore, to investigate the mechanism by which PON2 regulates ENaC, we expressed PON2 along with the ENaC subunits in fisher rat thyroid (FRT) cells, a system that is amenable to biochemical analyses of ENaC assembly and trafficking. We found that PON2 primarily resides in the endoplasmic reticulum (ER) in FRT cells, and its expression reduces the abundance of each ENaC subunit, reflecting enhanced subunit turnover. In contrast, no effect on the levels of mRNAs encoding the ENaC subunits was evident. Inhibition of lysosome function with chloroquine or NH4Cl did not alter the inhibitory effect of PON2 on ENaC expression. In contrast, PON2 accelerates ENaC degradation in a proteasome-dependent manner and acts before ENaC subunit ubiquitination. As a result of enhanced ENaC subunit ubiquitination and degradation, both channel surface expression and ENaC-mediated Na+ transport in FRT cells were reduced by PON2. Together, our data suggest that PON2 functions as an ER chaperone to monitor ENaC biogenesis and redirects the channel for ER-associated degradation.
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Affiliation(s)
- Shujie Shi
- 1Renal-Electrolyte Division, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Teresa M. Buck
- 2Deparment of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Andrew J. Nickerson
- 1Renal-Electrolyte Division, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Jeffrey L. Brodsky
- 2Deparment of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Thomas R. Kleyman
- 1Renal-Electrolyte Division, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania,3Department of Cell Biology, University of Pittsburgh, Pittsburgh, Pennsylvania,4Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, Pennsylvania
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Glaeser AB, Diniz BL, Santos AS, Guaraná BB, Muniz VF, Carlotto BS, Everling EM, Noguchi PY, Garcia AR, Miola J, Riegel M, Mergener R, Gazzola Zen PR, Machado Rosa RF. A child with cat-eye syndrome and oculo-auriculo-vertebral spectrum phenotype: A discussion around molecular cytogenetic findings. Eur J Med Genet 2021; 64:104319. [PMID: 34474176 DOI: 10.1016/j.ejmg.2021.104319] [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: 11/23/2020] [Revised: 06/23/2021] [Accepted: 08/22/2021] [Indexed: 10/20/2022]
Abstract
Cat eye syndrome (CES) is a rare chromosomal disorder that may be evident at birth. A small supernumerary chromosome is present, frequently has 2 centromeres, is bisatellited, and represents an inv dup(22)(q11) in those affected. It's known that the 22q11 region is associated with disorders involving higher and lower gene dosages. Conditions such as CES, 22q11 microduplication syndrome (Dup22q11) and oculoauriculovertebral spectrum phenotype (OAVS) may share genes belonging to this same region, which is known to have a predisposition to chromosomal rearrangements. The conditions, besides being related to chromosome 22, also share similar phenotypes. Here we have added a molecular evaluation update and results found of the first patient described with CES and OAVS phenotype, trying to explain the potential mechanism involved in the occurrence of this association.
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Affiliation(s)
- Andressa Barreto Glaeser
- Graduate Program in Pathology, Universidade Federal de Ciências da Saúde de Porto Alegre (UFCSPA), Porto Alegre, RS, Brazil
| | - Bruna Lixinski Diniz
- Graduate Program in Pathology, Universidade Federal de Ciências da Saúde de Porto Alegre (UFCSPA), Porto Alegre, RS, Brazil
| | | | | | | | - Bianca Soares Carlotto
- Graduate Program in Pathology, Universidade Federal de Ciências da Saúde de Porto Alegre (UFCSPA), Porto Alegre, RS, Brazil
| | | | | | | | - Juliana Miola
- Graduation in Medicine, UFCSPA, Porto Alegre, RS, Brazil
| | - Mariluce Riegel
- Graduate Program in Genetics and Molecular Biology, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil; Medical Genetics Service, Hospital de Clínicas de Porto Alegre (HCPA), Porto Alegre, RS, Brazil
| | - Rafaella Mergener
- Graduate Program in Genetics and Molecular Biology, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil
| | - Paulo Ricardo Gazzola Zen
- Graduate Program in Pathology, Universidade Federal de Ciências da Saúde de Porto Alegre (UFCSPA), Porto Alegre, RS, Brazil; Department of Internal Medicine, Clinical Genetics, UFCSPA and Irmandade da Santa Casa de Misericórdia de Porto Alegre (ISCMPA), Porto Alegre, RS, Brazil
| | - Rafael Fabiano Machado Rosa
- Graduate Program in Pathology, Universidade Federal de Ciências da Saúde de Porto Alegre (UFCSPA), Porto Alegre, RS, Brazil; Department of Internal Medicine, Clinical Genetics, UFCSPA and Irmandade da Santa Casa de Misericórdia de Porto Alegre (ISCMPA), Porto Alegre, RS, Brazil.
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8
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Zhang J, Yuan HK, Chen S, Zhang ZR. Detrimental or beneficial: Role of endothelial ENaC in vascular function. J Cell Physiol 2021; 237:29-48. [PMID: 34279047 DOI: 10.1002/jcp.30505] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 06/29/2021] [Accepted: 07/01/2021] [Indexed: 12/19/2022]
Abstract
In the past, it was believed that the expression of the epithelial sodium channel (ENaC) was restricted to epithelial tissues, such as the distal nephron, airway, sweat glands, and colon, where it is critical for sodium homeostasis. Over the past two decades, this paradigm has shifted due to the finding that ENaC is also expressed in various nonepithelial tissues, notably in vascular endothelial cells. In this review, the recent findings of the expression, regulation, and function of the endothelial ENaC (EnNaC) are discussed. The expression of EnNaC subunits is reported in a variety of endothelial cell lines and vasculatures, but this is controversial across different species and vessels and is not a universal finding in all vascular beds. The expression density of EnNaC is very faint compared to ENaC in the epithelium. To date, little is known about the regulatory mechanism of EnNaC. Through it can be regulated by aldosterone, the detailed downstream signaling remains elusive. EnNaC responds to increased extracellular sodium with the feedforward activation mechanism, which is quite different from the Na+ self-inhibition mechanism of ENaC. Functionally, EnNaC was shown to be a determinant of cellular mechanics and vascular tone as it can sense shear stress, and its activation or insertion into plasma membrane causes endothelial stiffness and reduced nitric oxide production. However, in some blood vessels, EnNaC is essential for maintaining the integrity of endothelial barrier function. In this context, we discuss the possible reasons for the distinct role of EnNaC in vasculatures.
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Affiliation(s)
- Jun Zhang
- School of Biomedical Sciences and Li Ka Shing Institute of Health Science, The Chinese University of Hong Kong, Hong Kong, China
| | - Hui-Kai Yuan
- Department of General Surgery, The First Affiliated Hospital of Harbin Medical University, Harbin, China
| | - Shuo Chen
- Department of Biopharmaceutical Sciences, School of Pharmacy, Harbin Medical University (Daqing), Daqing, China
| | - Zhi-Ren Zhang
- Departments of Pharmacy and Cardiology, Harbin Medical University Cancer Hospital, Institute of Metabolic Disease, Heilongjiang Academy of Medical Science, Heilongjiang Key Laboratory for Metabolic Disorder & Cancer Related Cardiovascular Diseases, NHC Key Laboratory of Cell Transplantation, Harbin Medical University & Key Laboratories of Education Ministry for Myocardial Ischemia Mechanism and Treatment, Harbin, China
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Mareš Š, Filipovský J, Vlková K, Pešta M, Černá V, Hrabák J, Mlíková Seidlerová J, Mayer O. A novel nonsense mutation in the β-subunit of the epithelial sodium channel causing Liddle syndrome. Blood Press 2021; 30:291-299. [PMID: 34223773 DOI: 10.1080/08037051.2021.1942785] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
PURPOSE Liddle syndrome is a hereditary form of arterial hypertension caused by mutations in the genes coding of the epithelial sodium channel - SCNN1A, SCNN1B and SCNN1G. It is characterised by early onset of hypertension and variable biochemical features such as hypokalaemia and low plasma concentrations of renin and aldosterone. Phenotypic variability is large and, therefore, LS is probably underdiagnosed. Our objective was to examine a family suspected from Liddle syndrome including genetic testing and evaluate clinical and biochemical features of affected family members. MATERIALS AND METHODS Thirteen probands from the Czech family, related by blood, underwent physical examination, laboratory tests, and genetic testing. Alleles of SCNN1B and SCNN1G genes were examined by PCR amplification and Sanger sequencing of amplicons. RESULTS We identified a novel mutation in the β-subunit of an epithelial sodium channel coded by the SCNN1B gene, causing the nonsense mutation in the protein sequence p.Tyr604*. This mutation was detected in 7 members of the family. The mutation carriers differed in the severity of hypertension and hypokalaemia which appeared only after diuretics in most of them; low aldosterone level (< 0.12 nmol/l) was, however, present in all. CONCLUSIONS This finding expands the spectrum of known mutations causing Liddle syndrome. Hypoaldosteronemia was 100% sensitive sign in the mutation carriers. Low levels are observed especially in the Caucasian population reaching 96% sensitivity. Assessment of plasma aldosterone concentration is helpful for differential diagnosis of arterial hypertension. CONDENSED ABSTRACT Liddle syndrome is a hereditary form of arterial hypertension caused by mutations in the genes encoding the epithelial sodium channel's α-, β- and γ-subunit. It is usually manifested by early onset of hypertension accompanied by low potassium and aldosterone levels. We performed a physical examination, laboratory tests and genetic screening in 13 members of a Czech family. We found a new mutation of the SCNN1B gene which encodes the β-subunit of the epithelial sodium channel. We describe the variability of each family member phenotype and point out the relevance of using aldosterone levels as a high sensitivity marker of Liddle syndrome in Caucasians.
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Affiliation(s)
- Štěpán Mareš
- Second Department of Internal Medicine, University Hospital, Pilsen, Czech Republic.,Biomedical Center, Faculty of Medicine in Pilsen, Charles University, Pilsen, Czech Republic
| | - Jan Filipovský
- Second Department of Internal Medicine, University Hospital, Pilsen, Czech Republic.,Biomedical Center, Faculty of Medicine in Pilsen, Charles University, Pilsen, Czech Republic
| | - Kateřina Vlková
- Biomedical Center, Faculty of Medicine in Pilsen, Charles University, Pilsen, Czech Republic.,Department of Microbiology, Faculty of Medicine in Pilsen, Charles University, Pilsen, Czech Republic
| | - Martin Pešta
- Biomedical Center, Faculty of Medicine in Pilsen, Charles University, Pilsen, Czech Republic.,Institute of Biology, Faculty of Medicine in Pilsen, Charles University, Pilsen, Czech Republic
| | - Václava Černá
- Institute of Biology, Faculty of Medicine in Pilsen, Charles University, Pilsen, Czech Republic
| | - Jaroslav Hrabák
- Biomedical Center, Faculty of Medicine in Pilsen, Charles University, Pilsen, Czech Republic.,Department of Microbiology, Faculty of Medicine in Pilsen, Charles University, Pilsen, Czech Republic
| | - Jitka Mlíková Seidlerová
- Second Department of Internal Medicine, University Hospital, Pilsen, Czech Republic.,Biomedical Center, Faculty of Medicine in Pilsen, Charles University, Pilsen, Czech Republic
| | - Otto Mayer
- Second Department of Internal Medicine, University Hospital, Pilsen, Czech Republic.,Biomedical Center, Faculty of Medicine in Pilsen, Charles University, Pilsen, Czech Republic
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10
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Cao Y, Yang Z, Chen Y, Jiang S, Wu Z, Ding B, Yang Y, Jin Z, Tang H. An Overview of the Posttranslational Modifications and Related Molecular Mechanisms in Diabetic Nephropathy. Front Cell Dev Biol 2021; 9:630401. [PMID: 34124032 PMCID: PMC8193943 DOI: 10.3389/fcell.2021.630401] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Accepted: 04/12/2021] [Indexed: 01/14/2023] Open
Abstract
Diabetic nephropathy (DN), a common diabetic microvascular complication, is characterized by its complex pathogenesis, higher risk of mortality, and the lack of effective diagnosis and treatment methods. Many studies focus on the diagnosis and treatment of diabetes mellitus (DM) and have reported that the pathophysiology of DN is very complex, involving many molecules and abnormal cellular activities. Given the respective pivotal roles of NF-κB, Nrf2, and TGF-β in inflammation, oxidative stress, and fibrosis during DN, we first review the effect of posttranslational modifications on these vital molecules in DN. Then, we describe the relationship between these molecules and related abnormal cellular activities in DN. Finally, we discuss some potential directions for DN treatment and diagnosis. The information reviewed here may be significant in the design of further studies to identify valuable therapeutic targets for DN.
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Affiliation(s)
- Yu Cao
- Department of Chinese Materia Medica and Natural Medicines, School of Pharmacy, The Air Force Medical University, Xi'an, China
| | - Zhao Yang
- Department of Gynaecology and Obstetrics, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China
| | - Ying Chen
- Department of Hematology, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China
| | - Shuai Jiang
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, Faculty of Life Sciences, Northwest University, Xi'an, China
| | - Zhen Wu
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, Faculty of Life Sciences, Northwest University, Xi'an, China
| | - Baoping Ding
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, Faculty of Life Sciences, Northwest University, Xi'an, China
| | - Yang Yang
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, Faculty of Life Sciences, Northwest University, Xi'an, China
| | - Zhenxiao Jin
- Department of Cardiovascular Surgery, Xijing Hospital, The Air Force Medical University, Xi'an, China
| | - Haifeng Tang
- Department of Chinese Materia Medica and Natural Medicines, School of Pharmacy, The Air Force Medical University, Xi'an, China
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11
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Cao X, Zhou Z, Tian Y, Liu Z, Cheng KO, Chen X, Hu W, Wong YM, Li X, Zhang H, Hu R, Huang P. Opposing roles of E3 ligases TRIM23 and TRIM21 in regulation of ion channel ANO1 protein levels. J Biol Chem 2021; 296:100738. [PMID: 33957127 PMCID: PMC8191318 DOI: 10.1016/j.jbc.2021.100738] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Revised: 04/19/2021] [Accepted: 04/29/2021] [Indexed: 02/06/2023] Open
Abstract
Anoctamin-1 (ANO1) (TMEM16A) is a calcium-activated chloride channel that plays critical roles in diverse physiological processes, such as sensory transduction and epithelial secretion. ANO1 levels have been shown to be altered under physiological and pathological conditions, although the molecular mechanisms that control ANO1 protein levels remain unclear. The ubiquitin–proteasome system is known to regulate the levels of numerous ion channels, but little information is available regarding whether and how ubiquitination regulates levels of ANO1. Here, we showed that two E3 ligases, TRIM23 and TRIM21, physically interact with the C terminus of ANO1. In vitro and in vivo assays demonstrated that whereas TRIM23 ubiquitinated ANO1 leading to its stabilization, TRIM21 ubiquitinated ANO1 and induced its degradation. Notably, ANO1 regulation by TRIM23 and TRIM21 is involved in chemical-induced pain sensation, salivary secretion, and heart-rate control in mice, and TRIM23 also mediates ANO1 upregulation induced by epidermal growth factor treatment. Our results suggest that these two antagonistic E3 ligases act together to control ANO1 expression and function. Our findings reveal a previously unrecognized mechanism for regulating ANO1 protein levels and identify a potential molecular link between ANO1 regulation, epidermal growth factor, and other signaling pathways.
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Affiliation(s)
- Xu Cao
- Division of Life Science, Hong Kong University of Science and Technology, Hong Kong, People's Republic of China
| | - Zijing Zhou
- Division of Life Science, Hong Kong University of Science and Technology, Hong Kong, People's Republic of China
| | - Ye Tian
- Division of Life Science, Hong Kong University of Science and Technology, Hong Kong, People's Republic of China
| | - Zhengzhao Liu
- Division of Life Science, Hong Kong University of Science and Technology, Hong Kong, People's Republic of China; State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai, China; Xiangya Hospital, Central South University, Changsha, China
| | - Kar On Cheng
- Division of Life Science, Hong Kong University of Science and Technology, Hong Kong, People's Republic of China
| | - Xibing Chen
- Division of Life Science, Hong Kong University of Science and Technology, Hong Kong, People's Republic of China
| | - Wenbao Hu
- Division of Life Science, Hong Kong University of Science and Technology, Hong Kong, People's Republic of China
| | - Yuk Ming Wong
- Division of Life Science, Hong Kong University of Science and Technology, Hong Kong, People's Republic of China
| | - Xiaofen Li
- Division of Life Science, Hong Kong University of Science and Technology, Hong Kong, People's Republic of China
| | - Hailin Zhang
- Department of Pharmacology, Hebei Medical University, Shijiazhuang, People's Republic of China
| | - Ronggui Hu
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai, China; Cancer Center, Shanghai Tenth People's Hospital, School of Medicine, Tongji University, Shanghai, China; School of Life Science, Hangzhou Institute for Advance Study, University of Chinese Academy of Sciences, Hangzhou, China
| | - Pingbo Huang
- Division of Life Science, Hong Kong University of Science and Technology, Hong Kong, People's Republic of China; Department of Chemical and Biological Engineering, Hong Kong University of Science and Technology, Hong Kong, People's Republic of China; State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, People's Republic of China; HKUST Shenzhen Research Institute, Hong Kong University of Science and Technology, Hong Kong, People's Republic of China; Hong Kong Branch of Guangdong Southern Marine Science and Engineering Laboratory (Guangzhou), Hong Kong University of Science and Technology, Hong Kong, People's Republic of China.
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12
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FAT10 protects against ischemia-induced ventricular arrhythmia by decreasing Nedd4-2/Nav1.5 complex formation. Cell Death Dis 2021; 12:25. [PMID: 33414395 PMCID: PMC7790828 DOI: 10.1038/s41419-020-03290-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2020] [Revised: 10/19/2020] [Accepted: 10/21/2020] [Indexed: 01/29/2023]
Abstract
The human leukocyte antigen F-associated transcript 10 (FAT10) is a member of the small ubiquitin-like protein family that binds to its target proteins and subjects them to degradation by the ubiquitin-proteasome system (UPS). In the heart, FAT10 plays a cardioprotective role and affects predisposition to cardiac arrhythmias after myocardial ischemia (MI). However, whether and how FAT10 influences cardiac arrhythmias is unknown. We investigated the role of FAT10 in regulating the sodium channel Nav1.5, a major regulator of cardiac arrhythmias. Fat10 was conditionally deleted in cardiac myocytes using Myh6-Cre and Fat10F/F mice (cFat10-/-). Compared with their wild-type littermates, cFat10-/- mice showed prolonged RR, PR, and corrected QT (QTc) intervals, were more likely to develop ventricular arrhythmia, and had increased mortality after MI. Patch-clamp studies showed that the peak Na+ current was reduced, and the late Na+ current was significantly augmented, resulting in a decreased action potential amplitude and delayed depolarization. Immunoblot and immunofluorescence analyses showed that the expression of the membrane protein Nav1.5 was decreased. Coimmunoprecipitation experiments demonstrated that FAT10 stabilized Nav1.5 expression by antagonizing Nav1.5 ubiquitination and degradation. Specifically, FAT10 bound to the lysine residues in the C-terminal fragments of Nav1.5 and decreased the binding of Nav1.5 to the Nedd4-2 protein, a ubiquitin E3 ligase, preventing degradation of the Nav1.5 protein. Collectively, our findings showed that deletion of the Fat10 in cardiac myocytes led to increased cardiac arrhythmias and increased mortality after MI. Thus, FAT10 protects against ischemia-induced ventricular arrhythmia by binding to Nav1.5 and preventing its Neddylation and degradation by the UPS after MI.
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13
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Fan P, Pan XC, Zhang D, Yang KQ, Zhang Y, Tian T, Luo F, Ma WJ, Liu YX, Wang LP, Zhang HM, Song L, Cai J, Zhou XL. Pediatric Liddle Syndrome Caused by a Novel SCNN1G Variant in a Chinese Family and Characterized by Early-Onset Hypertension. Am J Hypertens 2020; 33:670-675. [PMID: 32161960 PMCID: PMC7368168 DOI: 10.1093/ajh/hpaa037] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 03/02/2020] [Accepted: 03/06/2020] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Liddle syndrome (LS), an autosomal dominant disorder, is a common monogenic hypertension in pediatrics. In this study, we reported a novel SCNN1G variant in a Chinese family with pediatric LS, and conduct a systematic review of epithelial sodium channel (ENaC)-gene-positive LS cases to conclude the clinical genetic features of LS in childhood. METHODS Next-generation sequencing and in silico analysis were performed in the proband to discover candidate variants. Sanger sequencing was used to identify the predicted likely pathogenic variant. LS patients in this family were treated with amiloride. The Medline database was searched to summarize clinical features of pediatric LS cases whose age at genetic diagnosis was not more than 18 years. RESULTS Genetic analysis identified a novel SCNN1G missense variant (c.1874C>T, p.Pro625Leu) in the proband with LS in childhood. In silico analysis revealed this heterozygous variant was highly conserved and deleterious. A total of 38 publications described pediatric LS associated with 25 pathogenic variants in SCNN1B and SCNN1G in 54 children. Despite the phenotypic heterogeneity, early-onset hypertension is the most common feature. All LS patients in this family or the reviewed cases showed significantly improvements in hypertension and hypokalemia after treatment with ENaC inhibitors. CONCLUSIONS This study identified a novel SCNN1G missense variant in a patient with pediatric LS, expanding the genetic spectrum of SCNN1G and demonstrating the PY motif of γ-ENaC as a potential mutant region. Early identification and specific management of LS in children and adolescents are important to prevent the development of hypertensive end-organ disease.
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Affiliation(s)
- Peng Fan
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Xiao-Cheng Pan
- Department of Graduate School, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China
| | - Di Zhang
- Department of Emergency and Critical Care, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Kun-Qi Yang
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Ying Zhang
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Tao Tian
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Fang Luo
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Wen-Jun Ma
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Ya-Xin Liu
- Department of Emergency and Critical Care, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Lin-Ping Wang
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Hui-Min Zhang
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Lei Song
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Jun Cai
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Xian-Liang Zhou
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
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14
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Marunaka R, Marunaka Y. Interactive Actions of Aldosterone and Insulin on Epithelial Na + Channel Trafficking. Int J Mol Sci 2020; 21:ijms21103407. [PMID: 32408487 PMCID: PMC7279156 DOI: 10.3390/ijms21103407] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 05/08/2020] [Accepted: 05/09/2020] [Indexed: 11/29/2022] Open
Abstract
Epithelial Na+ channel (ENaC) participates in renal epithelial Na+ reabsorption, controlling blood pressure. Aldosterone and insulin elevate blood pressure by increasing the ENaC-mediated Na+ reabsorption. However, little information is available on the interactive action of aldosterone and insulin on the ENaC-mediated Na+ reabsorption. In the present study, we tried to clarify if insulin would modify the aldosterone action on the ENaC-mediated Na+ reabsorption from a viewpoint of intracellular ENaC trafficking. We measured the ENaC-mediated Na+ transport as short-circuit currents using a four-state mathematical ENaC trafficking model in renal A6 epithelial cells with or without aldosterone treatment under the insulin-stimulated and -unstimulated conditions. We found that: (A) under the insulin-stimulated condition, aldosterone treatment (1 µM for 20 h) significantly elevated the ENaC insertion rate to the apical membrane (kI) 3.3-fold and the ENaC recycling rate (kR) 2.0-fold, but diminished the ENaC degradation rate (kD) 0.7-fold without any significant effect on the ENaC endocytotic rate (kE); (B) under the insulin-unstimulated condition, aldosterone treatment decreased kE 0.5-fold and increased kR 1.4-fold, without any significant effect on kI or kD. Thus, the present study indicates that: (1) insulin masks the well-known inhibitory action of aldosterone on the ENaC endocytotic rate; (2) insulin induces a stimulatory action of aldosterone on ENaC apical insertion and an inhibitory action of aldosterone on ENaC degradation; (3) insulin enhances the aldosterone action on ENaC recycling; (4) insulin has a more effective action on diminution of ENaC endocytosis than aldosterone.
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Affiliation(s)
- Rie Marunaka
- Research Institute for Clinical Physiology, Kyoto Industrial Health Association, Kyoto 604-8472, Japan;
- Okamura Dental Clinic, Chuo-ku, Osaka 541-0041, Japan
| | - Yoshinori Marunaka
- Research Institute for Clinical Physiology, Kyoto Industrial Health Association, Kyoto 604-8472, Japan;
- Research Center for Drug Discovery and Pharmaceutical Development Science, Research Organization of Science and Technology, Ritsumeikan University, Kusatsu 525-8577, Japan
- Department of Molecular Cell Physiology, Kyoto Prefectural University of Medicine Graduate School of Medical Science, Kyoto 602-8566, Japan
- Correspondence: ; Tel.: +81-75-802-0135
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15
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Zhu J, Tsai NP. Ubiquitination and E3 Ubiquitin Ligases in Rare Neurological Diseases with Comorbid Epilepsy. Neuroscience 2020; 428:90-99. [DOI: 10.1016/j.neuroscience.2019.12.030] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Revised: 12/16/2019] [Accepted: 12/17/2019] [Indexed: 12/19/2022]
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16
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Kozina AA, Trofimova TA, Okuneva EG, Baryshnikova NV, Obuhova VA, Krasnenko AY, Tsukanov KY, Klimchuk OI, Surkova EI, Shatalov PA, Ilinsky VV. Liddle syndrome due to a novel mutation in the γ subunit of the epithelial sodium channel (ENaC) in family from Russia: a case report. BMC Nephrol 2019; 20:389. [PMID: 31655555 PMCID: PMC6815463 DOI: 10.1186/s12882-019-1579-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Accepted: 10/03/2019] [Indexed: 12/16/2022] Open
Abstract
Background Liddle syndrome is a monogenic disease with autosomal dominant inheritance. Basic characteristics of this disease are hypertension, reduced concentration of aldosterone and renin activity, as well as increased excretion of potassium leading to low level of potassium in serum and metabolic alkalosis. The cause of Liddle syndrome is missense or frameshift mutations in SCNN1A, SCNN1B, or SCNN1G genes that encode epithelial sodium channel subunits. Case presentation We describe a family with Liddle syndrome from Russia. 15-year-old proband has arterial hypertension, hypokalemia, hyporeninemia, metabolic alkalosis, but aldosterone level is within the normal range. At 12 years of age, arterial hypertension was noticed for the first time. We identified novel frameshift mutation c.1769delG (p.Gly590Alafs) in SCNN1G, which encodes the γ subunit of ENaC in vertebrates. The father and younger sister also harbor this heterozygous deletion. Treatment with amiloride of proband and his sister did not normalize the blood pressure, but normalized level of plasma renin activity. Conclusions Our results expand the mutational spectrum of Liddle syndrome and provide further proof that the conserved PY motif is crucial to control of ENaC activity. Genetic analysis has implications for the management of hypertension, specific treatment with amiloride and counselling in families with Liddle syndrome.
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Affiliation(s)
- Anastasiya A Kozina
- Institute of Biomedical Chemistry, Pogodinskaya street 10 building 8, 119121, Moscow, Russia.,Pirogov Russian National Research Medical University, Ostrovitianova street 1, 117997, Moscow, Russia
| | - Tatiana A Trofimova
- Veltischev Research and Clinical Institute for Pediatrics of the Pirogov Russian National Research Medical University, Taldomskaya str 2, 125412, Moscow, Russia
| | - Elena G Okuneva
- Genotek Ltd., Nastavnicheskii pereulok 17/1, 105120, Moscow, Russia
| | - Natalia V Baryshnikova
- Pirogov Russian National Research Medical University, Ostrovitianova street 1, 117997, Moscow, Russia.,Genotek Ltd., Nastavnicheskii pereulok 17/1, 105120, Moscow, Russia
| | - Varvara A Obuhova
- Veltischev Research and Clinical Institute for Pediatrics of the Pirogov Russian National Research Medical University, Taldomskaya str 2, 125412, Moscow, Russia
| | - Anna Yu Krasnenko
- Pirogov Russian National Research Medical University, Ostrovitianova street 1, 117997, Moscow, Russia.,Genotek Ltd., Nastavnicheskii pereulok 17/1, 105120, Moscow, Russia
| | | | | | | | - Peter A Shatalov
- Veltischev Research and Clinical Institute for Pediatrics of the Pirogov Russian National Research Medical University, Taldomskaya str 2, 125412, Moscow, Russia.,Genotek Ltd., Nastavnicheskii pereulok 17/1, 105120, Moscow, Russia
| | - Valery V Ilinsky
- Institute of Biomedical Chemistry, Pogodinskaya street 10 building 8, 119121, Moscow, Russia.,Pirogov Russian National Research Medical University, Ostrovitianova street 1, 117997, Moscow, Russia.,Genotek Ltd., Nastavnicheskii pereulok 17/1, 105120, Moscow, Russia.,Vavilov Institute of General Genetics, Gubkina street 3, 119333, Moscow, Russia
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Fan P, Zhao YM, Zhang D, Liao Y, Yang KQ, Tian T, Lou Y, Luo F, Ma WJ, Zhang HM, Song L, Cai J, Liu YX, Zhou XL. A Novel Frameshift Mutation of SCNN1G Causing Liddle Syndrome with Normokalemia. Am J Hypertens 2019; 32:752-758. [PMID: 30977777 PMCID: PMC6636789 DOI: 10.1093/ajh/hpz053] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Revised: 03/13/2019] [Accepted: 04/09/2019] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Liddle syndrome (LS) is an autosomal dominant disorder caused by single-gene mutations of the epithelial sodium channel (ENaC). It is characterized by early-onset hypertension, spontaneous hypokalemia and low plasma renin and aldosterone concentrations. In this study, we reported an LS pedigree with normokalemia resulting from a novel SCNN1G frameshift mutation. METHODS Peripheral blood samples were collected from the proband and eight family members for DNA extraction. Next-generation sequencing and Sanger sequencing were performed to identify the SCNN1G mutation. Clinical examinations were used to comprehensively evaluate the phenotypes of two patients. RESULTS Genetic analysis identified a novel SCNN1G frameshift mutation, p.Arg586Valfs*598, in the proband with LS. This heterozygous frameshift mutation generated a premature stop codon and deleted the vital PY motif of ENaC. The same mutation was present in his elder brother with LS, and his mother without any LS symptoms. Biochemical examination showed normokalemia in the three mutation carriers. The mutation identified was not found in any other family members, 100 hypertensives, or 100 healthy controls. CONCLUSIONS Our study identified a novel SCNN1G frameshift mutation in a Chinese family with LS, expanding the genetic spectrum of SCNN1G. Genetic testing helped us identify LS with a pathogenic mutation when the genotypes and phenotype were not completely consistent because of the hypokalemia. This case emphasizes that once a proband is diagnosed with LS by genetic testing, family genetic sequencing is necessary for early diagnosis and intervention for other family members, to protect against severe cardiovascular complications.
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Affiliation(s)
- Peng Fan
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Yu-Mo Zhao
- Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China
| | - Di Zhang
- Department of Emergency and Critical Care Center, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Ying Liao
- Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China
| | - Kun-Qi Yang
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Tao Tian
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Ying Lou
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Fang Luo
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Wen-Jun Ma
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Hui-Min Zhang
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Lei Song
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Jun Cai
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Ya-Xin Liu
- Department of Emergency and Critical Care Center, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Xian-Liang Zhou
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
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18
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Park M, Jung HG, Kweon HJ, Kim YE, Park JY, Hwang EM. The E3 ubiquitin ligase, NEDD4L (NEDD4-2) regulates bestrophin-1 (BEST1) by ubiquitin-dependent proteolysis. Biochem Biophys Res Commun 2019; 514:344-350. [PMID: 31036321 DOI: 10.1016/j.bbrc.2019.04.078] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Accepted: 04/11/2019] [Indexed: 11/26/2022]
Abstract
The bestrophin family comprises well-known Ca2+-activated chloride channels (CaCC) that are expressed in a variety tissues including the brain, eye, gastrointestinal tract, and muscle tissues. Among the family members, bestrophin-1 (BEST1) is known to exist mainly in retinal pigment epithelium cells, but we recently reported that BEST1 mediates Ca2+-activated Cl- currents in hippocampal astrocytes. Despite its critical roles in physiological processes, including tonic γ-aminobutyric acid release and glutamate transport, the mechanisms that regulate BEST1 are poorly understood. In this study, we identified NEDD4L (NEDD4-2), an E3 ubiquitin ligase, as a binding partner of BEST1. A series of deletion constructs revealed that the WW3-4 domains of NEDD4L were important for interaction with BEST1. We observed that BEST1 underwent ubiquitin-dependent proteolysis and found that the conserved lysine370 residue in the C-terminus of BEST1 was important for its ubiquitination. Finally, we demonstrated that NEDD4L inhibited whole cell currents mediated by BEST1 but not by the BEST1(K370R) mutant. Collectively, our data demonstrated that NEDD4L played a critical role in regulating the surface expression of BEST1 by promoting its internalization and degradation.
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Affiliation(s)
- Myeongki Park
- Center for Functional Connectomics, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea; Neuroscience Program, University of Science and Technology (UST), Daejeon, 305-350, Republic of Korea
| | - Hyun-Gug Jung
- Center for Functional Connectomics, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea; School of Biosystem and Biomedical Science, College of Health Science, Korea University, Seoul, 02841, Republic of Korea
| | - Hae-Jin Kweon
- Neuroscience Discovery, Janssen Pharmaceutical Companies of Johnson & Johnson, 3210 Merryfield Row, San Diego, CA, 92121, USA
| | - Yeong-Eun Kim
- Center for Functional Connectomics, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea; Neuroscience Program, University of Science and Technology (UST), Daejeon, 305-350, Republic of Korea
| | - Jae-Yong Park
- School of Biosystem and Biomedical Science, College of Health Science, Korea University, Seoul, 02841, Republic of Korea.
| | - Eun Mi Hwang
- Center for Functional Connectomics, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea; Neuroscience Program, University of Science and Technology (UST), Daejeon, 305-350, Republic of Korea.
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Abstract
PURPOSE OF REVIEW The review describes studies investigating the role of microRNAs in the signaling pathway of the mineralocorticoid hormone, aldosterone. RECENT FINDINGS Emerging evidence indicates that aldosterone alters the expression of microRNAs in target tissues thereby modulating the expression of key regulatory proteins. SUMMARY The mineralocorticoid hormone aldosterone is released by the adrenal glands in a homeostatic mechanism to regulate blood volume. The long-term renal action of aldosterone is to increase the retrieval of sodium from filtered plasma to restore blood pressure. Emerging evidence indicates aldosterone may alter noncoding RNAs (ncRNAs) to integrate this hormonal response in target tissue. Expression of the best characterized small ncRNAs, microRNAs, is regulated by aldosterone stimulation. MicroRNAs modulate protein expression at all steps in the renin-angiotensin-aldosterone-signaling (RAAS) system. In addition to acting as a rheostat to fine-tune protein levels in aldosterone-responsive cells, there is evidence that microRNAs down-regulate components of the signaling cascade as a feedback mechanism. The role of microRNAs is, therefore, as signal integrator, and damper in aldosterone signaling, which has implications in understating the RAAS system from both a physiological and pathophysiological perspective. Recent evidence for microRNA's role in RAAS signaling will be discussed.
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20
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Fan P, Lu CX, Zhang D, Yang KQ, Lu PP, Zhang Y, Meng X, Hao SF, Luo F, Liu YX, Zhang HM, Song L, Cai J, Zhang X, Zhou XL. Liddle syndrome misdiagnosed as primary aldosteronism resulting from a novel frameshift mutation of SCNN1B. Endocr Connect 2018; 7:1528-1534. [PMID: 30496127 PMCID: PMC6311463 DOI: 10.1530/ec-18-0484] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Accepted: 11/28/2018] [Indexed: 12/18/2022]
Abstract
Liddle syndrome (LS), a monogenetic autosomal dominant disorder, is mainly characterized by early-onset hypertension and hypokalemia. Clinically, misdiagnosis or missing diagnosis is common, since clinical phenotypes of LS are variable and nonspecific. We report a family with misdiagnosis of primary aldosteronism (PA), but identify as LS with a pathogenic frameshift mutation of the epithelial sodium channel (ENaC) β subunit. DNA samples were collected from a 32-year-old proband and 31 other relatives in the same family. A designed panel including 41 genes associated with monogenic hypertension was screened using next-generation sequencing. The best candidate disease-causing variants were verified by Sanger sequencing. Genetic analysis of the proband revealed a novel frameshift mutation c.1838delC (p.Pro613Glnfs*675) in exon 13 of SCNN1B. This heterozygous mutation involved the deletion of a cytosine from a string of three consecutive cytosines located at codons 612 to 613 and resulted in deletion of the crucial PY motif and elongation of the β-ENaC protein. The identical mutation was also found in 12 affected family members. Amiloride was effective in alleviating LS for patients. There were no SCNN1A or SCNN1G mutations in this family. Our study emphasizes the importance of considering LS in the differential diagnosis of early-onset hypertension. The identification of a novel frameshift mutation of SCNN1B enriches the genetic spectrum of LS and has allowed treatment of this affected family to prevent severe complications.
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Affiliation(s)
- Peng Fan
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Chao-Xia Lu
- McKusick-Zhang Center for Genetic Medicine, State Key Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Di Zhang
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Kun-Qi Yang
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Pei-Pei Lu
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Ying Zhang
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Xu Meng
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Su-Fang Hao
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Fang Luo
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Ya-Xin Liu
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Hui-Min Zhang
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Lei Song
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Jun Cai
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Xue Zhang
- McKusick-Zhang Center for Genetic Medicine, State Key Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
- Correspondence should be addressed to X Zhang or X-L Zhou: or
| | - Xian-Liang Zhou
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
- Correspondence should be addressed to X Zhang or X-L Zhou: or
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21
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Nanami M, Pham TD, Kim YH, Yang B, Sutliff RL, Staub O, Klein JD, Lopez-Cayuqueo KI, Chambrey R, Park AY, Wang X, Pech V, Verlander JW, Wall SM. The Role of Intercalated Cell Nedd4-2 in BP Regulation, Ion Transport, and Transporter Expression. J Am Soc Nephrol 2018; 29:1706-1719. [PMID: 29773687 DOI: 10.1681/asn.2017080826] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Accepted: 03/29/2018] [Indexed: 12/23/2022] Open
Abstract
BackgroundNedd4-2 is an E3 ubiquitin-protein ligase that associates with transport proteins, causing their ubiquitylation, and then internalization and degradation. Previous research has suggested a correlation between Nedd4-2 and BP. In this study, we explored the effect of intercalated cell (IC) Nedd4-2 gene ablation on IC transporter abundance and function and on BP.Methods We generated IC Nedd4-2 knockout mice using Cre-lox technology and produced global pendrin/Nedd4-2 null mice by breeding global Nedd4-2 null (Nedd4-2-/- ) mice with global pendrin null (Slc26a4-/- ) mice. Mice ate a diet with 1%-4% NaCl; BP was measured by tail cuff and radiotelemetry. We measured transepithelial transport of Cl- and total CO2 and transepithelial voltage in cortical collecting ducts perfused in vitro Transporter abundance was detected with immunoblots, immunohistochemistry, and immunogold cytochemistry.Results IC Nedd4-2 gene ablation markedly increased electroneutral Cl-/HCO3- exchange in the cortical collecting duct, although benzamil-, thiazide-, and bafilomycin-sensitive ion flux changed very little. IC Nedd4-2 gene ablation did not increase the abundance of type B IC transporters, such as AE4 (Slc4a9), H+-ATPase, barttin, or the Na+-dependent Cl-/HCO3- exchanger (Slc4a8). However, IC Nedd4-2 gene ablation increased CIC-5 total protein abundance, apical plasma membrane pendrin abundance, and the ratio of pendrin expression on the apical membrane to the cytoplasm. IC Nedd4-2 gene ablation increased BP by approximately 10 mm Hg. Moreover, pendrin gene ablation eliminated the increase in BP observed in global Nedd4-2 knockout mice.Conclusions IC Nedd4-2 regulates Cl-/HCO3- exchange in ICs., Nedd4-2 gene ablation increases BP in part through its action in these cells.
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Affiliation(s)
| | | | | | - Baoli Yang
- Department of Obstetrics and Gynecology, University of Iowa, Iowa City, Iowa
| | | | - Olivier Staub
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland.,National Centre of Competence in Research "Kidney.ch," Zurich, Switzerland
| | | | - Karen I Lopez-Cayuqueo
- Centro de Estudios Cientificos, Valdivia, Chile.,Institut National de la Santé et de la Recherche Médicale U970, Paris Cardiovascular Research Center, Université Paris-Descartes, Paris, France
| | - Regine Chambrey
- Institut National de la Santé et de la Recherche Médicale U1188, Universite de la Reunion, Plateforme Cyclotron Réunion Océan Indien, St. Denis, Ile de la Reunion, France; and
| | | | | | | | - Jill W Verlander
- Renal Division, Department of Medicine, University of Florida at Gainesville, Gainesville, Florida
| | - Susan M Wall
- Renal and .,Department of Physiology, Emory University School of Medicine, Atlanta, Georgia
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22
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Olesen CW, Vogensen J, Axholm I, Severin M, Schnipper J, Pedersen IS, von Stemann JH, Schrøder JM, Christensen DP, Pedersen SF. Trafficking, localization and degradation of the Na +,HCO 3- co-transporter NBCn1 in kidney and breast epithelial cells. Sci Rep 2018; 8:7435. [PMID: 29743600 PMCID: PMC5943355 DOI: 10.1038/s41598-018-25059-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Accepted: 04/13/2018] [Indexed: 01/28/2023] Open
Abstract
The Na+;HCO3− co-transporter NBCn1 (SLC4A7) is a major regulator of intracellular pH yet its trafficking and turnover are essentially unstudied. Here, we used MDCK-II and MCF-7 cells to investigate these processes in epithelial cells. GFP-NBCn1 membrane localization was abolished by truncation of the full NBCn1 C-terminal tail (C-tail) yet did not require the C-terminal PDZ-binding motif (ETSL). Glutathione-S-Transferase-pulldown of the C-tail followed by mass spectrometry analysis revealed putative interactions with multiple sorting-, degradation- and retention factors, including the scaffolding protein RACK1. Pulldown of FLAG-tagged deletion constructs mapped the RACK1 interaction to the proximal NBCn1 C-tail. Proximity Ligation Assay and co-immunoprecipitation confirmed that native NBCn1 interacts with RACK1 in a cellular context. Consistent with a functional role of this complex, RACK1 knockdown reduced NBCn1 membrane localization without affecting total NBCn1 expression. Notably, only non-confluent cells exhibited detectable NBCn1-RACK1 plasma membrane co-localization, suggesting that RACK1 regulates the trafficking of NBCn1 to the membrane. Whereas total NBCn1 degradation was slow, with a half-life of more than 24 h, one-third of surface NBCn1 was constitutively endocytosed from the basolateral membrane within 60 min. This suggests that a fraction of NBCn1 exhibits recycling between the basolateral membrane and intracellular compartment(s). Our findings have important implications for understanding NBCn1 regulation as well as its dysregulation in disease.
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Affiliation(s)
- Christina Wilkens Olesen
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen, Universitetsparken 13, DK-2100, Copenhagen Ø, Denmark
| | - Jens Vogensen
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen, Universitetsparken 13, DK-2100, Copenhagen Ø, Denmark
| | - Ida Axholm
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen, Universitetsparken 13, DK-2100, Copenhagen Ø, Denmark
| | - Marc Severin
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen, Universitetsparken 13, DK-2100, Copenhagen Ø, Denmark
| | - Julie Schnipper
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen, Universitetsparken 13, DK-2100, Copenhagen Ø, Denmark
| | - Isabella Skandorff Pedersen
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen, Universitetsparken 13, DK-2100, Copenhagen Ø, Denmark
| | - Jakob Hjorth von Stemann
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen, Universitetsparken 13, DK-2100, Copenhagen Ø, Denmark
| | - Jacob Morville Schrøder
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen, Universitetsparken 13, DK-2100, Copenhagen Ø, Denmark
| | - Dan Ploug Christensen
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen, Universitetsparken 13, DK-2100, Copenhagen Ø, Denmark.
| | - Stine Falsig Pedersen
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen, Universitetsparken 13, DK-2100, Copenhagen Ø, Denmark.
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23
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Abstract
Liddle syndrome is an inherited form of low-renin hypertension, transmitted with an autosomal dominant pattern. The molecular basis of Liddle syndrome resides in germline mutations of the SCNN1A, SCNN1B and SCNN1G genes, encoding the α, β, and γ-subunits of the epithelial Na+ channel (ENaC), respectively. To date, 31 different causative mutations have been reported in 72 families from four continents. The majority of the substitutions cause an increased expression of the channel at the distal nephron apical membrane, with subsequent enhanced renal sodium reabsorption. The most common clinical presentation of the disease is early onset hypertension, hypokalemia, metabolic alkalosis, suppressed plasma renin activity and low plasma aldosterone. Consequently, treatment of Liddle syndrome is based on the administration of ENaC blockers, amiloride and triamterene. Herein, we discuss the genetic basis, clinical presentation, diagnosis and treatment of Liddle syndrome. Finally, we report a new case in an Italian family, caused by a SCNN1B p.Pro618Leu substitution.
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24
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Ronchi VP, Kim ED, Summa CM, Klein JM, Haas AL. In silico modeling of the cryptic E2∼ubiquitin-binding site of E6-associated protein (E6AP)/UBE3A reveals the mechanism of polyubiquitin chain assembly. J Biol Chem 2017; 292:18006-18023. [PMID: 28924046 DOI: 10.1074/jbc.m117.813477] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Indexed: 12/13/2022] Open
Abstract
To understand the mechanism for assembly of Lys48-linked polyubiquitin degradation signals, we previously demonstrated that the E6AP/UBE3A ligase harbors two functionally distinct E2∼ubiquitin-binding sites: a high-affinity Site 1 required for E6AP Cys820∼ubiquitin thioester formation and a canonical Site 2 responsible for subsequent chain elongation. Ordered binding to Sites 1 and 2 is here revealed by observation of UbcH7∼ubiquitin-dependent substrate inhibition of chain formation at micromolar concentrations. To understand substrate inhibition, we exploited the PatchDock algorithm to model in silico UbcH7∼ubiquitin bound to Site 1, validated by chain assembly kinetics of selected point mutants. The predicted structure buries an extensive solvent-excluded surface bringing the UbcH7∼ubiquitin thioester bond within 6 Å of the Cys820 nucleophile. Modeling onto the active E6AP trimer suggests that substrate inhibition arises from steric hindrance between Sites 1 and 2 of adjacent subunits. Confirmation that Sites 1 and 2 function in trans was demonstrated by examining the effect of E6APC820A on wild-type activity and single-turnover pulse-chase kinetics. A cyclic proximal indexation model proposes that Sites 1 and 2 function in tandem to assemble thioester-linked polyubiquitin chains from the proximal end attached to Cys820 before stochastic en bloc transfer to the target protein. Non-reducing SDS-PAGE confirms assembly of the predicted Cys820-linked 125I-polyubiquitin thioester intermediate. Other studies suggest that Glu550 serves as a general base to generate the Cys820 thiolate within the low dielectric binding interface and Arg506 functions to orient Glu550 and to stabilize the incipient anionic transition state during thioester exchange.
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Affiliation(s)
| | - Elizabeth D Kim
- From the Department of Biochemistry and Molecular Biology and
| | - Christopher M Summa
- the Department of Computer Science, University of New Orleans, New Orleans, Louisiana 70148
| | | | - Arthur L Haas
- From the Department of Biochemistry and Molecular Biology and .,the Stanley S. Scott Cancer Center, Louisiana State University Health Sciences Center, New Orleans, Louisiana 70112 and
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25
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Lee BSL, Devor DC, Hamilton KL. Modulation of Retrograde Trafficking of KCa3.1 in a Polarized Epithelium. Front Physiol 2017; 8:489. [PMID: 28769813 PMCID: PMC5513911 DOI: 10.3389/fphys.2017.00489] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Accepted: 06/26/2017] [Indexed: 12/14/2022] Open
Abstract
In epithelia, the intermediate conductance, Ca2+-activated K+ channel (KCa3.1) is targeted to the basolateral membrane (BLM) where this channel plays numerous roles in absorption and secretion. A growing body of research suggests that the membrane resident population of KCa3.1 may be critical in clinical manifestation of diseases. In this study, we investigated the key molecular components that regulate the degradation of KCa3.1 using a Fisher rat thyroid cell line stably expressing KCa3.1. Using immunoblot, Ussing chamber, and pharmacological approaches, we demonstrated that KCa3.1 is targeted exclusively to the BLM, provided a complete time course of degradation of KCa3.1 and degradation time courses of the channel in the presence of pharmacological inhibitors of ubiquitylation and deubiquitylation to advance our understanding of the retrograde trafficking of KCa3.1. We provide a complete degradation profile of KCa3.1 and that the degradation is via an ubiquitin-dependent pathway. Inhibition of E1 ubiquitin activating enzyme by UBEI-41 crippled the ability of the cells to internalize the channel, shown by the increased BLM surface expression resulting in an increased function of the channel as measured by a DCEBIO sensitive K+ current. Additionally, the involvement of deubiquitylases and degradation by the lysosome were also confirmed by treating the cells with PR-619 or leupeptin/pepstatin, respectively; which significantly decreased the degradation rate of membrane KCa3.1. Additionally, we provided the first evidence that KCa3.1 channels were not deubiquitylated at the BLM. These data further define the retrograde trafficking of KCa3.1, and may provide an avenue for therapeutic approach for treatment of disease.
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Affiliation(s)
- Bob Shih-Liang Lee
- Department of Physiology, School of Biomedical Sciences, University of OtagoDunedin, New Zealand
| | - Daniel C Devor
- Department of Cell Biology, University of Pittsburgh School of MedicinePittsburgh, PA, United States
| | - Kirk L Hamilton
- Department of Physiology, School of Biomedical Sciences, University of OtagoDunedin, New Zealand
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26
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Vinaiphat A, Aluksanasuwan S, Manissorn J, Sutthimethakorn S, Thongboonkerd V. Response of renal tubular cells to differential types and doses of calcium oxalate crystals: Integrative proteome network analysis and functional investigations. Proteomics 2017. [DOI: 10.1002/pmic.201700192] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Arada Vinaiphat
- Medical Proteomics Unit, Office for Research and Development, Faculty of Medicine Siriraj Hospital; and Center for Research in Complex Systems Science; Mahidol University; Bangkok Thailand
| | - Siripat Aluksanasuwan
- Medical Proteomics Unit, Office for Research and Development, Faculty of Medicine Siriraj Hospital; and Center for Research in Complex Systems Science; Mahidol University; Bangkok Thailand
| | - Juthatip Manissorn
- Medical Proteomics Unit, Office for Research and Development, Faculty of Medicine Siriraj Hospital; and Center for Research in Complex Systems Science; Mahidol University; Bangkok Thailand
| | - Suchitra Sutthimethakorn
- Medical Proteomics Unit, Office for Research and Development, Faculty of Medicine Siriraj Hospital; and Center for Research in Complex Systems Science; Mahidol University; Bangkok Thailand
| | - Visith Thongboonkerd
- Medical Proteomics Unit, Office for Research and Development, Faculty of Medicine Siriraj Hospital; and Center for Research in Complex Systems Science; Mahidol University; Bangkok Thailand
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27
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Yang KQ, Lu CX, Fan P, Zhang Y, Meng X, Dong XQ, Luo F, Liu YX, Zhang HM, Wu HY, Cai J, Zhang X, Zhou XL. Genetic screening of SCNN1B and SCNN1G genes in early-onset hypertensive patients helps to identify Liddle syndrome. Clin Exp Hypertens 2017; 40:107-111. [PMID: 28718682 DOI: 10.1080/10641963.2017.1334799] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Kun-Qi Yang
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Chao-Xia Lu
- McKusick-Zhang Center for Genetic Medicine, State Key Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Peng Fan
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Ying Zhang
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Xu Meng
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Xue-Qi Dong
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Fang Luo
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Ya-Xin Liu
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Hui-Min Zhang
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Hai-Ying Wu
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Jun Cai
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Xue Zhang
- McKusick-Zhang Center for Genetic Medicine, State Key Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Xian-Liang Zhou
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
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28
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Vadász I, Sznajder JI. Gas Exchange Disturbances Regulate Alveolar Fluid Clearance during Acute Lung Injury. Front Immunol 2017; 8:757. [PMID: 28725223 PMCID: PMC5495863 DOI: 10.3389/fimmu.2017.00757] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Accepted: 06/15/2017] [Indexed: 01/07/2023] Open
Abstract
Disruption of the alveolar-capillary barrier and accumulation of pulmonary edema, if not resolved, result in poor alveolar gas exchange leading to hypoxia and hypercapnia, which are hallmarks of acute lung injury and the acute respiratory distress syndrome (ARDS). Alveolar fluid clearance (AFC) is a major function of the alveolar epithelium and is mediated by the concerted action of apically-located Na+ channels [epithelial Na+ channel (ENaC)] and the basolateral Na,K-ATPase driving vectorial Na+ transport. Importantly, those patients with ARDS who cannot clear alveolar edema efficiently have worse outcomes. While hypoxia can be improved in most cases by O2 supplementation and mechanical ventilation, the use of lung protective ventilation settings can lead to further CO2 retention. Whether the increase in CO2 concentrations has deleterious or beneficial effects have been a topic of significant controversy. Of note, both low O2 and elevated CO2 levels are sensed by the alveolar epithelium and by distinct and specific molecular mechanisms impair the function of the Na,K-ATPase and ENaC thereby inhibiting AFC and leading to persistence of alveolar edema. This review discusses recent discoveries on the sensing and signaling events initiated by hypoxia and hypercapnia and the relevance of these results in identification of potential novel therapeutic targets in the treatment of ARDS.
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Affiliation(s)
- István Vadász
- Department of Internal Medicine, Justus Liebig University, Universities of Giessen and Marburg Lung Center, Giessen, Germany
| | - Jacob I Sznajder
- Division of Pulmonary and Critical Care Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
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29
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Gwoździńska P, Buchbinder BA, Mayer K, Herold S, Morty RE, Seeger W, Vadász I. Hypercapnia Impairs ENaC Cell Surface Stability by Promoting Phosphorylation, Polyubiquitination and Endocytosis of β-ENaC in a Human Alveolar Epithelial Cell Line. Front Immunol 2017; 8:591. [PMID: 28588583 PMCID: PMC5440515 DOI: 10.3389/fimmu.2017.00591] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2017] [Accepted: 05/04/2017] [Indexed: 01/11/2023] Open
Abstract
Acute lung injury is associated with formation of pulmonary edema leading to impaired gas exchange. Patients with acute respiratory distress syndrome (ARDS) require mechanical ventilation to improve oxygenation; however, the use of relatively low tidal volumes (to minimize further injury of the lung) often leads to further accumulation of carbon dioxide (hypercapnia). Hypercapnia has been shown to impair alveolar fluid clearance (AFC), thereby causing retention of pulmonary edema, and may lead to worse outcomes; however, the underlying molecular mechanisms remain incompletely understood. AFC is critically dependent on the epithelial sodium channel (ENaC), which drives the vectorial transport of Na+ across the alveolar epithelium. Thus, in the current study, we investigated the mechanisms by which hypercapnia effects ENaC cell surface stability in alveolar epithelial cells (AECs). Elevated CO2 levels led to polyubiquitination of β-ENaC and subsequent endocytosis of the α/β-ENaC complex in AECs, which were prevented by silencing the E3 ubiquitin ligase, Nedd4-2. Hypercapnia-induced ubiquitination and cell surface retrieval of ENaC were critically dependent on phosphorylation of the Thr615 residue of β-ENaC, which was mediated by the extracellular signal-regulated kinase (ERK)1/2. Furthermore, activation of ERK1/2 led to subsequent activation of AMP-activated protein kinase (AMPK) and c-Jun N-terminal kinase (JNK)1/2 that in turn phosphorylated Nedd4-2 at the Thr899 residue. Importantly, mutation of Thr899 to Ala markedly inhibited the CO2-induced polyubiquitination of β-ENaC and restored cell surface stability of the ENaC complex, highlighting the critical role of Nedd4-2 phosphorylation status in targeting ENaC. Collectively, our data suggest that elevated CO2 levels promote activation of the ERK/AMPK/JNK axis in a human AEC line, in which ERK1/2 phosphorylates β-ENaC whereas JNK mediates phosphorylation of Nedd4-2, thereby facilitating the channel-ligase interaction. The hypercapnia-induced ENaC dysfunction may contribute to impaired alveolar edema clearance and thus, interfering with these molecular mechanisms may improve alveolar fluid balance and lead to better outcomes in patients with ARDS.
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Affiliation(s)
- Paulina Gwoździńska
- Department of Internal Medicine, Justus Liebig University, Universities of Giessen and Marburg Lung Center, German Center for Lung Research, Giessen, Germany
| | - Benno A Buchbinder
- Department of Internal Medicine, Justus Liebig University, Universities of Giessen and Marburg Lung Center, German Center for Lung Research, Giessen, Germany
| | - Konstantin Mayer
- Department of Internal Medicine, Justus Liebig University, Universities of Giessen and Marburg Lung Center, German Center for Lung Research, Giessen, Germany
| | - Susanne Herold
- Department of Internal Medicine, Justus Liebig University, Universities of Giessen and Marburg Lung Center, German Center for Lung Research, Giessen, Germany
| | - Rory E Morty
- Department of Internal Medicine, Justus Liebig University, Universities of Giessen and Marburg Lung Center, German Center for Lung Research, Giessen, Germany.,Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Werner Seeger
- Department of Internal Medicine, Justus Liebig University, Universities of Giessen and Marburg Lung Center, German Center for Lung Research, Giessen, Germany.,Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - István Vadász
- Department of Internal Medicine, Justus Liebig University, Universities of Giessen and Marburg Lung Center, German Center for Lung Research, Giessen, Germany
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30
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Buck TM, Jordahl AS, Yates ME, Preston GM, Cook E, Kleyman TR, Brodsky JL. Interactions between intersubunit transmembrane domains regulate the chaperone-dependent degradation of an oligomeric membrane protein. Biochem J 2017; 474:357-376. [PMID: 27903760 PMCID: PMC5423784 DOI: 10.1042/bcj20160760] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Revised: 11/28/2016] [Accepted: 11/30/2016] [Indexed: 12/22/2022]
Abstract
In the kidney, the epithelial sodium channel (ENaC) regulates blood pressure through control of sodium and volume homeostasis, and in the lung, ENaC regulates the volume of airway and alveolar fluids. ENaC is a heterotrimer of homologous α-, β- and γ-subunits, and assembles in the endoplasmic reticulum (ER) before it traffics to and functions at the plasma membrane. Improperly folded or orphaned ENaC subunits are subject to ER quality control and targeted for ER-associated degradation (ERAD). We previously established that a conserved, ER lumenal, molecular chaperone, Lhs1/GRP170, selects αENaC, but not β- or γ-ENaC, for degradation when the ENaC subunits were individually expressed. We now find that when all three subunits are co-expressed, Lhs1-facilitated ERAD was blocked. To determine which domain-domain interactions between the ENaC subunits are critical for chaperone-dependent quality control, we employed a yeast model and expressed chimeric α/βENaC constructs in the context of the ENaC heterotrimer. We discovered that the βENaC transmembrane domain was sufficient to prevent the Lhs1-dependent degradation of the α-subunit in the context of the ENaC heterotrimer. Our work also found that Lhs1 delivers αENaC for proteasome-mediated degradation after the protein has become polyubiquitinated. These data indicate that the Lhs1 chaperone selectively recognizes an immature form of αENaC, one which has failed to correctly assemble with the other channel subunits via its transmembrane domain.
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Affiliation(s)
- Teresa M Buck
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA, U.S.A
| | - Alexa S Jordahl
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA, U.S.A
| | - Megan E Yates
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA, U.S.A
| | - G Michael Preston
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA, U.S.A
| | - Emily Cook
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA, U.S.A
| | - Thomas R Kleyman
- Department of Medicine, Renal-Electrolyte Division, University of Pittsburgh, Pittsburgh, PA, U.S.A
| | - Jeffrey L Brodsky
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA, U.S.A
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31
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You H, Ge Y, Zhang J, Cao Y, Xing J, Su D, Huang Y, Li M, Qu S, Sun F, Liang X. Derlin-1 promotes ubiquitylation and degradation of the epithelial Na + channel, ENaC. J Cell Sci 2017; 130:1027-1036. [PMID: 28137758 DOI: 10.1242/jcs.198242] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Accepted: 01/24/2017] [Indexed: 11/20/2022] Open
Abstract
Ubiquitylation of the epithelial Na+ channel (ENaC) plays a critical role in cellular functions, including transmembrane transport of Na+, Na+ and water balance, and blood pressure stabilization. Published studies have suggested that ENaC subunits are targets of ER-related degradation (ERAD) in yeast systems. However, the molecular mechanism underlying proteasome-mediated degradation of ENaC subunits remains to be established. Derlin-1, an E3 ligase mediator, links recognized target proteins to ubiquitin-mediated proteasomal degradation in the cytosol. In the present study, we found that derlin-1 suppressed the expression of ENaC at the protein level and that the subunit α-ENaC (also known as SCNN1A) physically interacted with derlin-1 at the membrane-anchored domains or the loop regions, and that derlin-1 initiated α-ENaC retrotranslocation. In addition, HUWE1, an endoplasmic reticulum (ER)-resident E3 ubiquitin ligase, was recruited and promoted K11-linked polyubiquitylation of α-ENaC and, hence, formation of an α-ENaC ubiquitin-mediated degradation complex. These findings suggest that derlin-1 promotes ENaC ubiquitylation and enhances ENaC ubiquitin- mediated proteasome degradation. The derlin-1 pathway therefore may represent a significant early checkpoint in the recognition and degradation of ENaC in mammalian cells.
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Affiliation(s)
- Hui You
- Renal Division, Sir Run Run Hospital, Department of Pathophysiology, Nanjing Medical University, Nanjing, Jiangsu Province, 211166, China.,Department of Endocrinology and Metabolism, Shanghai Tenth People's Hospital, Tong-Ji University, Shanghai, 200072, China
| | - Yamei Ge
- Renal Division, Sir Run Run Hospital, Department of Pathophysiology, Nanjing Medical University, Nanjing, Jiangsu Province, 211166, China
| | - Jian Zhang
- Renal Division, Sir Run Run Hospital, Department of Pathophysiology, Nanjing Medical University, Nanjing, Jiangsu Province, 211166, China
| | - Yizhi Cao
- Renal Division, Sir Run Run Hospital, Department of Pathophysiology, Nanjing Medical University, Nanjing, Jiangsu Province, 211166, China
| | - Jing Xing
- Renal Division, Sir Run Run Hospital, Department of Pathophysiology, Nanjing Medical University, Nanjing, Jiangsu Province, 211166, China
| | - Dongming Su
- Center of Pathology and Clinical Laboratory, Sir Run Run Hospital, Nanjing Medical University, Nanjing, Jiangsu Province, 211166, China
| | - Yujie Huang
- Renal Division, Sir Run Run Hospital, Department of Pathophysiology, Nanjing Medical University, Nanjing, Jiangsu Province, 211166, China
| | - Min Li
- Renal Division, Sir Run Run Hospital, Department of Pathophysiology, Nanjing Medical University, Nanjing, Jiangsu Province, 211166, China
| | - Shen Qu
- Department of Endocrinology and Metabolism, Shanghai Tenth People's Hospital, Tong-Ji University, Shanghai, 200072, China
| | - Fei Sun
- Department of Physiology, School of Medicine, Wayne State University, Detroit, MI 48201, USA
| | - Xiubin Liang
- Renal Division, Sir Run Run Hospital, Department of Pathophysiology, Nanjing Medical University, Nanjing, Jiangsu Province, 211166, China
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Cullin 7 mediates proteasomal and lysosomal degradations of rat Eag1 potassium channels. Sci Rep 2017; 7:40825. [PMID: 28098200 PMCID: PMC5241692 DOI: 10.1038/srep40825] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Accepted: 12/12/2016] [Indexed: 11/08/2022] Open
Abstract
Mammalian Eag1 (Kv10.1) potassium (K+) channels are widely expressed in the brain. Several mutations in the gene encoding human Eag1 K+ channel have been associated with congenital neurodevelopmental anomalies. Currently very little is known about the molecules mediating protein synthesis and degradation of Eag1 channels. Herein we aim to ascertain the protein degradation mechanism of rat Eag1 (rEag1). We identified cullin 7 (Cul7), a member of the cullin-based E3 ubiquitin ligase family, as a novel rEag1 binding partner. Immunoprecipitation analyses confirmed the interaction between Cul7 and rEag1 in heterologous cells and neuronal tissues. Cul7 and rEag1 also exhibited significant co-localization at synaptic regions in neurons. Over-expression of Cul7 led to reduced protein level, enhanced ubiquitination, accelerated protein turn-over, and decreased current density of rEag1 channels. We provided further biochemical and morphological evidence suggesting that Cul7 targeted endoplasmic reticulum (ER)- and plasma membrane-localized rEag1 to the proteasome and the lysosome, respectively, for protein degradation. Cul7 also contributed to protein degradation of a disease-associated rEag1 mutant. Together, these results indicate that Cul7 mediates both proteasomal and lysosomal degradations of rEag1. Our findings provide a novel insight to the mechanisms underlying ER and peripheral protein quality controls of Eag1 channels.
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33
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Lou Y, Zhang F, Luo Y, Wang L, Huang S, Jin F. Serum and Glucocorticoid Regulated Kinase 1 in Sodium Homeostasis. Int J Mol Sci 2016; 17:ijms17081307. [PMID: 27517916 PMCID: PMC5000704 DOI: 10.3390/ijms17081307] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Revised: 08/02/2016] [Accepted: 08/03/2016] [Indexed: 12/13/2022] Open
Abstract
The ubiquitously expressed serum and glucocorticoid regulated kinase 1 (SGK1) is tightly regulated by osmotic and hormonal signals, including glucocorticoids and mineralocorticoids. Recently, SGK1 has been implicated as a signal hub for the regulation of sodium transport. SGK1 modulates the activities of multiple ion channels and carriers, such as epithelial sodium channel (ENaC), voltage-gated sodium channel (Nav1.5), sodium hydrogen exchangers 1 and 3 (NHE1 and NHE3), sodium-chloride symporter (NCC), and sodium-potassium-chloride cotransporter 2 (NKCC2); as well as the sodium-potassium adenosine triphosphatase (Na+/K+-ATPase) and type A natriuretic peptide receptor (NPR-A). Accordingly, SGK1 is implicated in the physiology and pathophysiology of Na+ homeostasis. Here, we focus particularly on recent findings of SGK1’s involvement in Na+ transport in renal sodium reabsorption, hormone-stimulated salt appetite and fluid balance and discuss the abnormal SGK1-mediated Na+ reabsorption in hypertension, heart disease, edema with diabetes, and embryo implantation failure.
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Affiliation(s)
- Yiyun Lou
- Department of Reproductive Endocrinology, Women's Hospital, School of Medicine, Zhejiang University, Hangzhou 310006, Zhejiang, China.
- Department of Gynaecology, Hangzhou Hospital of Traditional Chinese Medicine, Hangzhou 310007, Zhejiang, China.
| | - Fan Zhang
- Department of Reproductive Endocrinology, Women's Hospital, School of Medicine, Zhejiang University, Hangzhou 310006, Zhejiang, China.
| | - Yuqin Luo
- Department of Reproductive Endocrinology, Women's Hospital, School of Medicine, Zhejiang University, Hangzhou 310006, Zhejiang, China.
| | - Liya Wang
- Department of Reproductive Endocrinology, Women's Hospital, School of Medicine, Zhejiang University, Hangzhou 310006, Zhejiang, China.
| | - Shisi Huang
- Department of Reproductive Endocrinology, Women's Hospital, School of Medicine, Zhejiang University, Hangzhou 310006, Zhejiang, China.
| | - Fan Jin
- Department of Reproductive Endocrinology, Women's Hospital, School of Medicine, Zhejiang University, Hangzhou 310006, Zhejiang, China.
- Key Laboratory of Reproductive Genetics, National Ministry of Education (Zhejiang University), Women's Reproductive Healthy Laboratory of Zhejiang Province, Hangzhou 310058, Zhejiang, China.
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34
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Vélez P, Schwartz AB, Iyer SR, Warrington A, Fadool DA. Ubiquitin ligase Nedd4-2 modulates Kv1.3 current amplitude and ion channel protein targeting. J Neurophysiol 2016; 116:671-85. [PMID: 27146988 DOI: 10.1152/jn.00874.2015] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Accepted: 05/04/2016] [Indexed: 11/22/2022] Open
Abstract
Voltage-dependent potassium channels (Kv) go beyond the stabilization of the resting potential and regulate biochemical pathways, regulate intracellular signaling, and detect energy homeostasis. Because targeted deletion and pharmacological block of the Kv1.3 channel protein produce marked changes in metabolism, resistance to diet-induced obesity, and changes in olfactory structure and function, this investigation explored Nedd4-2-mediated ubiquitination and degradation to regulate Kv1.3 channel density. Heterologous coexpression of Nedd4-2 ligase and Kv1.3 in HEK 293 cells reduced Kv1.3 current density without modulation of kinetic properties as measured by patch-clamp electrophysiology. Modulation of current density was dependent on ligase activity and was lost through point mutation of cysteine 938 in the catalytic site of the ligase (Nedd4-2CS). Incorporation of adaptor protein Grb10 relieved Nedd4-2-induced current suppression as did application of the proteasome inhibitor Mg-132. SDS-PAGE and immunoprecipitation strategies demonstrated a channel/adaptor/ligase signalplex. Pixel immunodensity was reduced for Kv1.3 in the presence of Nedd4-2, which was eliminated upon additional incorporation of Grb10. We confirmed Nedd4-2/Grb10 coimmunoprecipitation and observed an increased immunodensity for Nedd4-2 in the presence of Kv1.3 plus Grb10, regardless of whether the catalytic site was active. Kv1.3/Nedd4-2 were reciprocally coimmunoprecipated, whereby mutation of the COOH-terminal, SH3-recognition (493-498), or ubiquitination sites on Kv1.3 (lysines 467, 476, 498) retained coimmunoprecipitation, while the latter prevented the reduction in channel density. A model is presented for which an atypical interaction outside the canonical PY motif may permit channel/ligase interaction to lead to protein degradation and reduced current density, which can involve Nedd4-2/Grb10 interactions to disrupt Kv1.3 loss of current density.
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Affiliation(s)
- Patricio Vélez
- Program in Neuroscience, Florida State University, Tallahassee, Florida
| | - Austin B Schwartz
- Institute of Molecular Biophysics, Florida State University, Tallahassee, Florida; and
| | - Subashini R Iyer
- Program in Neuroscience, Florida State University, Tallahassee, Florida
| | - Anthony Warrington
- Department of Biological Sciences, Florida State University, Tallahassee, Florida
| | - Debra Ann Fadool
- Program in Neuroscience, Florida State University, Tallahassee, Florida; Institute of Molecular Biophysics, Florida State University, Tallahassee, Florida; and Department of Biological Sciences, Florida State University, Tallahassee, Florida
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Hanukoglu I, Hanukoglu A. Epithelial sodium channel (ENaC) family: Phylogeny, structure-function, tissue distribution, and associated inherited diseases. Gene 2016; 579:95-132. [PMID: 26772908 PMCID: PMC4756657 DOI: 10.1016/j.gene.2015.12.061] [Citation(s) in RCA: 238] [Impact Index Per Article: 29.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2015] [Revised: 12/20/2015] [Accepted: 12/22/2015] [Indexed: 01/24/2023]
Abstract
The epithelial sodium channel (ENaC) is composed of three homologous subunits and allows the flow of Na(+) ions across high resistance epithelia, maintaining body salt and water homeostasis. ENaC dependent reabsorption of Na(+) in the kidney tubules regulates extracellular fluid (ECF) volume and blood pressure by modulating osmolarity. In multi-ciliated cells, ENaC is located in cilia and plays an essential role in the regulation of epithelial surface liquid volume necessary for cilial transport of mucus and gametes in the respiratory and reproductive tracts respectively. The subunits that form ENaC (named as alpha, beta, gamma and delta, encoded by genes SCNN1A, SCNN1B, SCNN1G, and SCNN1D) are members of the ENaC/Degenerin superfamily. The earliest appearance of ENaC orthologs is in the genomes of the most ancient vertebrate taxon, Cyclostomata (jawless vertebrates) including lampreys, followed by earliest representatives of Gnathostomata (jawed vertebrates) including cartilaginous sharks. Among Euteleostomi (bony vertebrates), Actinopterygii (ray finned-fishes) branch has lost ENaC genes. Yet, most animals in the Sarcopterygii (lobe-finned fish) branch including Tetrapoda, amphibians and amniotes (lizards, crocodiles, birds, and mammals), have four ENaC paralogs. We compared the sequences of ENaC orthologs from 20 species and established criteria for the identification of ENaC orthologs and paralogs, and their distinction from other members of the ENaC/Degenerin superfamily, especially ASIC family. Differences between ENaCs and ASICs are summarized in view of their physiological functions and tissue distributions. Structural motifs that are conserved throughout vertebrate ENaCs are highlighted. We also present a comparative overview of the genotype-phenotype relationships in inherited diseases associated with ENaC mutations, including multisystem pseudohypoaldosteronism (PHA1B), Liddle syndrome, cystic fibrosis-like disease and essential hypertension.
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Affiliation(s)
- Israel Hanukoglu
- Laboratory of Cell Biology, Faculty of Natural Sciences, Ariel University, Ariel, Israel.
| | - Aaron Hanukoglu
- Division of Pediatric Endocrinology, E. Wolfson Medical Center, Holon, Israel; Sackler School of Medicine, Tel-Aviv University, Tel Aviv, Israel
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Evangelinos M, Martzoukou O, Chorozian K, Amillis S, Diallinas G. BsdA(Bsd2) -dependent vacuolar turnover of a misfolded version of the UapA transporter along the secretory pathway: prominent role of selective autophagy. Mol Microbiol 2016; 100:893-911. [PMID: 26917498 DOI: 10.1111/mmi.13358] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/19/2016] [Indexed: 12/13/2022]
Abstract
Transmembrane proteins translocate cotranslationally in the endoplasmic reticulum (ER) membrane and traffic as vesicular cargoes, via the Golgi, in their final membrane destination. Misfolding in the ER leads to protein degradation basically through the ERAD/proteasome system. Here, we use a mutant version of the purine transporter UapA (ΔR481) to show that specific misfolded versions of plasma membrane cargoes undergo vacuolar turnover prior to localization in the plasma membrane. We show that non-endocytic vacuolar turnover of ΔR481 is dependent on BsdA(Bsd2) , an ER transmembrane adaptor of HulA(Rsp5) ubiquitin ligase. We obtain in vivo evidence that BsdA(Bsd2) interacts with HulA(Rsp5) and ΔR481, primarily in the ER. Importantly, accumulation of ΔR481 in the ER triggers delivery of the selective autophagy marker Atg8 in vacuoles along with ΔR481. Genetic block of autophagy (atg9Δ, rabO(ts) ) reduces, but does not abolish, sorting of ΔR481 in the vacuoles, suggesting that a fraction of the misfolded transporter might be redirected for vacuolar degradation via the Golgi. Our results support that multiple routes along the secretory pathway operate for the detoxification of Aspergillus nidulans cells from misfolded membrane proteins and that BsdA is a key factor for marking specific misfolded cargoes.
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Affiliation(s)
- Minoas Evangelinos
- Faculty of Biology, University of Athens, Panepistimioupolis, 15784, Athens, Greece
| | - Olga Martzoukou
- Faculty of Biology, University of Athens, Panepistimioupolis, 15784, Athens, Greece
| | - Koar Chorozian
- Faculty of Biology, University of Athens, Panepistimioupolis, 15784, Athens, Greece
| | - Sotiris Amillis
- Faculty of Biology, University of Athens, Panepistimioupolis, 15784, Athens, Greece
| | - George Diallinas
- Faculty of Biology, University of Athens, Panepistimioupolis, 15784, Athens, Greece
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Palma AG, Galizia L, Kotsias BA, Marino GI. CFTR channel in oocytes from Xenopus laevis and its regulation by xShroom1 protein. Pflugers Arch 2016; 468:871-80. [PMID: 26888038 DOI: 10.1007/s00424-016-1800-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Revised: 01/18/2016] [Accepted: 02/10/2016] [Indexed: 01/24/2023]
Abstract
Shroom is a family of related proteins linked to the actin cytoskeleton. xShroom1 is constitutively expressed in Xenopus laevis oocytes, and it is required for the expression of the epithelial sodium channel (ENaC). As there is a close relationship between ENaC and the cystic fibrosis transmembrane regulator (CFTR), we examined the action of xShroom1 on CFTR expression and activity. Biotinylation was used to measure CFTR surface expression, and currents were registered with voltage clamp when stimulated with forskolin and 3-isobutyl-1-methylxanthine. Oocytes were coinjected with CFTR complementary RNAs (cRNAs) and xShroom1 sense or antisense oligonucleotides. We observed an increment in CFTR currents and CFTR surface expression in oocytes coinjected with CFTR and xShroom1 antisense oligonucleotides. MG-132, a proteasome inhibitor, did not prevent the increment in currents when xShroom1 was suppressed by antisense oligonucleotides. In addition, we inhibited the delivery of newly synthesized proteins to the plasma membrane with BFA and we found that the half-life of plasma membrane CFTR was prolonged when coinjected with the xShroom1 antisense oligonucleotides. Chloroquine, an inhibitor of the late endosome/lysosome, did not significantly increase CFTR currents when xShroom1 expression was inhibited. The higher expression of CFTR when xShroom1 is suppressed is in concordance with the functional studies suggesting that the suppression of the xShroom1 protein resulted in an increment in CFTR currents by promoting the increase of the half-life of CFTR in the plasma membrane. The role of xShroom1 in regulating CFTR expression could be relevant in the understanding of the channel malfunction in several diseases.
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Affiliation(s)
- Alejandra G Palma
- Laboratorio de Canales Iónicos, Instituto de Investigaciones Médicas Alfredo Lanari, Universidad de Buenos Aires, IDIM-CONICET, C. de Malvinas 3150, 1427, Buenos Aires, Argentina
| | - Luciano Galizia
- Laboratorio de Canales Iónicos, Instituto de Investigaciones Médicas Alfredo Lanari, Universidad de Buenos Aires, IDIM-CONICET, C. de Malvinas 3150, 1427, Buenos Aires, Argentina
| | - Basilio A Kotsias
- Laboratorio de Canales Iónicos, Instituto de Investigaciones Médicas Alfredo Lanari, Universidad de Buenos Aires, IDIM-CONICET, C. de Malvinas 3150, 1427, Buenos Aires, Argentina
| | - Gabriela I Marino
- Laboratorio de Canales Iónicos, Instituto de Investigaciones Médicas Alfredo Lanari, Universidad de Buenos Aires, IDIM-CONICET, C. de Malvinas 3150, 1427, Buenos Aires, Argentina.
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38
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Sodium-Proton (Na+/H+) Antiporters: Properties and Roles in Health and Disease. Met Ions Life Sci 2016; 16:391-458. [DOI: 10.1007/978-3-319-21756-7_12] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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39
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Andersen MN, Hefting LL, Steffensen AB, Schmitt N, Olesen SP, Olsen JV, Lundby A, Rasmussen HB. Protein kinase A stimulates Kv7.1 surface expression by regulating Nedd4-2-dependent endocytic trafficking. Am J Physiol Cell Physiol 2015; 309:C693-706. [PMID: 26405101 DOI: 10.1152/ajpcell.00383.2014] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Accepted: 09/15/2015] [Indexed: 11/22/2022]
Abstract
The potassium channel Kv7.1 plays critical physiological roles in both heart and epithelial tissues. In heart, Kv7.1 and the accessory subunit KCNE1 forms the slowly activating delayed-rectifier potassium current current, which is enhanced by protein kinase A (PKA)-mediated phosphorylation. The observed current increase requires both phosphorylation of Kv7.1 and the presence of KCNE1. However, PKA also stimulates Kv7.1 currents in epithelial tissues, such as colon, where the channel does not coassemble with KCNE1. Here, we demonstrate that PKA activity significantly impacts the subcellular localization of Kv7.1 in Madin-Darby canine kidney cells. While PKA inhibition reduced the fraction of channels at the cell surface, PKA activation increased it. We show that PKA inhibition led to intracellular accumulation of Kv7.1 in late endosomes/lysosomes. By mass spectroscopy we identified eight phosphorylated residues on Kv7.1, however, none appeared to play a role in the observed response. Instead, we found that PKA acted by regulating endocytic trafficking involving the ubiquitin ligase Nedd4-2. We show that a Nedd4-2-resistant Kv7.1-mutant displayed significantly reduced intracellular accumulation upon PKA inhibition. Similar effects were observed upon siRNA knockdown of Nedd4-2. However, although Nedd4-2 is known to regulate Kv7.1 by ubiquitylation, biochemical analyses demonstrated that PKA did not influence the amount of Nedd4-2 bound to Kv7.1 or the ubiquitylation level of the channel. This suggests that PKA influences Nedd4-2-dependent Kv7.1 transport though a different molecular mechanism. In summary, we identify a novel mechanism whereby PKA can increase Kv7.1 current levels, namely by regulating Nedd4-2-dependent Kv7.1 transport.
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Affiliation(s)
- Martin N Andersen
- The Danish National Research Foundation Center for Cardiac Arrhythmia and The Faculty of Health and Medical Sciences, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark; and
| | - Louise L Hefting
- The Danish National Research Foundation Center for Cardiac Arrhythmia and The Faculty of Health and Medical Sciences, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark; and
| | - Annette B Steffensen
- The Danish National Research Foundation Center for Cardiac Arrhythmia and The Faculty of Health and Medical Sciences, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark; and
| | - Nicole Schmitt
- The Danish National Research Foundation Center for Cardiac Arrhythmia and The Faculty of Health and Medical Sciences, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark; and
| | - Søren-Peter Olesen
- The Danish National Research Foundation Center for Cardiac Arrhythmia and The Faculty of Health and Medical Sciences, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark; and
| | - Jesper V Olsen
- Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Alicia Lundby
- The Danish National Research Foundation Center for Cardiac Arrhythmia and The Faculty of Health and Medical Sciences, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark; and Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Hanne B Rasmussen
- The Danish National Research Foundation Center for Cardiac Arrhythmia and The Faculty of Health and Medical Sciences, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark; and
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Abriel H, Rougier JS, Jalife J. Ion channel macromolecular complexes in cardiomyocytes: roles in sudden cardiac death. Circ Res 2015; 116:1971-88. [PMID: 26044251 DOI: 10.1161/circresaha.116.305017] [Citation(s) in RCA: 92] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The movement of ions across specific channels embedded on the membrane of individual cardiomyocytes is crucial for the generation and propagation of the cardiac electric impulse. Emerging evidence over the past 20 years strongly suggests that the normal electric function of the heart is the result of dynamic interactions of membrane ion channels working in an orchestrated fashion as part of complex molecular networks. Such networks work together with exquisite temporal precision to generate each action potential and contraction. Macromolecular complexes play crucial roles in transcription, translation, oligomerization, trafficking, membrane retention, glycosylation, post-translational modification, turnover, function, and degradation of all cardiac ion channels known to date. In addition, the accurate timing of each cardiac beat and contraction demands, a comparable precision on the assembly and organizations of sodium, calcium, and potassium channel complexes within specific subcellular microdomains, where physical proximity allows for prompt and efficient interaction. This review article, part of the Compendium on Sudden Cardiac Death, discusses the major issues related to the role of ion channel macromolecular assemblies in normal cardiac electric function and the mechanisms of arrhythmias leading to sudden cardiac death. It provides an idea of how these issues are being addressed in the laboratory and in the clinic, which important questions remain unanswered, and what future research will be needed to improve knowledge and advance therapy.
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Affiliation(s)
- Hugues Abriel
- From the Department of Clinical Research, University of Bern, Bern, Switzerland (H.A., J.-S.R.); Center for Arrhythmia Research, Department of Internal Medicine, University of Michigan, Ann Arbor (J.J.); and Area of Myocardial Pathophysiology, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain (J.J.)
| | - Jean-Sébastien Rougier
- From the Department of Clinical Research, University of Bern, Bern, Switzerland (H.A., J.-S.R.); Center for Arrhythmia Research, Department of Internal Medicine, University of Michigan, Ann Arbor (J.J.); and Area of Myocardial Pathophysiology, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain (J.J.)
| | - José Jalife
- From the Department of Clinical Research, University of Bern, Bern, Switzerland (H.A., J.-S.R.); Center for Arrhythmia Research, Department of Internal Medicine, University of Michigan, Ann Arbor (J.J.); and Area of Myocardial Pathophysiology, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain (J.J.).
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41
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USP18 Sensitivity of Peptide Transporters PEPT1 and PEPT2. PLoS One 2015; 10:e0129365. [PMID: 26046984 PMCID: PMC4457862 DOI: 10.1371/journal.pone.0129365] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2014] [Accepted: 05/07/2015] [Indexed: 11/20/2022] Open
Abstract
USP18 (Ubiquitin-like specific protease 18) is an enzyme cleaving ubiquitin from target proteins. USP18 plays a pivotal role in antiviral and antibacterial immune responses. On the other hand, ubiquitination participates in the regulation of several ion channels and transporters. USP18 sensitivity of transporters has, however, never been reported. The present study thus explored, whether USP18 modifies the activity of the peptide transporters PEPT1 and PEPT2, and whether the peptide transporters are sensitive to the ubiquitin ligase Nedd4-2. To this end, cRNA encoding PEPT1 or PEPT2 was injected into Xenopus laevis oocytes without or with additional injection of cRNA encoding USP18. Electrogenic peptide (glycine-glycine) transport was determined by dual electrode voltage clamp. As a result, in Xenopus laevis oocytes injected with cRNA encoding PEPT1 or PEPT2, but not in oocytes injected with water or with USP18 alone, application of the dipeptide gly-gly (2 mM) was followed by the appearance of an inward current (Igly-gly). Coexpression of USP18 significantly increased Igly-gly in both PEPT1 and PEPT2 expressing oocytes. Kinetic analysis revealed that coexpression of USP18 increased maximal Igly-gly. Conversely, overexpression of the ubiquitin ligase Nedd4-2 decreased Igly-gly. Coexpression of USP30 similarly increased Igly-gly in PEPT1 expressing oocytes. In conclusion, USP18 sensitive cellular functions include activity of the peptide transporters PEPT1 and PEPT2.
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Pech V, Wall SM, Nanami M, Bao HF, Kim YH, Lazo-Fernandez Y, Yue Q, Pham TD, Eaton DC, Verlander JW. Pendrin gene ablation alters ENaC subcellular distribution and open probability. Am J Physiol Renal Physiol 2015; 309:F154-63. [PMID: 25972513 DOI: 10.1152/ajprenal.00564.2014] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2014] [Accepted: 05/04/2015] [Indexed: 01/15/2023] Open
Abstract
The present study explored whether the intercalated cell Cl(-)/HCO3(-) exchanger pendrin modulates epithelial Na(+) channel (ENaC) function by changing channel open probability and/or channel density. To do so, we measured ENaC subunit subcellular distribution by immunohistochemistry, single channel recordings in split open cortical collecting ducts (CCDs), as well as transepithelial voltage and Na(+) absorption in CCDs from aldosterone-treated wild-type and pendrin-null mice. Because pendrin gene ablation reduced 70-kDa more than 85-kDa γ-ENaC band density, we asked if pendrin gene ablation interferes with ENaC cleavage. We observed that ENaC-cleaving protease application (trypsin) increased the lumen-negative transepithelial voltage in pendrin-null mice but not in wild-type mice, which raised the possibility that pendrin gene ablation blunts ENaC cleavage, thereby reducing open probability. In mice harboring wild-type ENaC, pendrin gene ablation reduced ENaC-mediated Na(+) absorption by reducing channel open probability as well as by reducing channel density through changes in subunit total protein abundance and subcellular distribution. Further experiments used mice with blunted ENaC endocytosis and degradation (Liddle's syndrome) to explore the significance of pendrin-dependent changes in ENaC open probability. In mouse models of Liddle's syndrome, pendrin gene ablation did not change ENaC subunit total protein abundance, subcellular distribution, or channel density, but markedly reduced channel open probability. We conclude that in mice harboring wild-type ENaC, pendrin modulates ENaC function through changes in subunit abundance, subcellular distribution, and channel open probability. In a mouse model of Liddle's syndrome, however, pendrin gene ablation reduces channel activity mainly through changes in open probability.
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Affiliation(s)
- Vladimir Pech
- Department of Medicine, Emory University School of Medicine, Atlanta, Georgia
| | - Susan M Wall
- Department of Medicine, Emory University School of Medicine, Atlanta, Georgia; Department of Physiology, Emory University School of Medicine, Atlanta, Georgia; and
| | - Masayoshi Nanami
- Department of Medicine, Emory University School of Medicine, Atlanta, Georgia
| | - Hui-Fang Bao
- Department of Physiology, Emory University School of Medicine, Atlanta, Georgia; and
| | - Young Hee Kim
- Department of Medicine, Emory University School of Medicine, Atlanta, Georgia
| | | | - Qiang Yue
- Department of Physiology, Emory University School of Medicine, Atlanta, Georgia; and
| | - Truyen D Pham
- Department of Medicine, Emory University School of Medicine, Atlanta, Georgia
| | - Douglas C Eaton
- Department of Physiology, Emory University School of Medicine, Atlanta, Georgia; and
| | - Jill W Verlander
- Department of Medicine, University of Florida, Gainesville, Florida
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Marqués MC, Zamarbide-Forés S, Pedelini L, Llopis-Torregrosa V, Yenush L. A functional Rim101 complex is required for proper accumulation of the Ena1 Na+-ATPase protein in response to salt stress in Saccharomyces cerevisiae. FEMS Yeast Res 2015; 15:fov017. [PMID: 25934176 DOI: 10.1093/femsyr/fov017] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/07/2015] [Indexed: 12/14/2022] Open
Abstract
The maintenance of ionic homeostasis is essential for cell viability, thus the activity of plasma membrane ion transporters must be tightly controlled. Previous studies in Saccharomyces cerevisiae revealed that the proper trafficking of several nutrient permeases requires the E3 ubiquitin ligase Rsp5 and, in many cases, the presence of specific adaptor proteins needed for Rsp5 substrate recognition. Among these adaptor proteins are nine members of the arrestin-related trafficking adaptor (ART) family. We studied the possible role of the ART family in the regulation of monovalent cation transporters. We show here that the salt sensitivity phenotype of the rim8/art9 mutant is due to severe defects in Ena1 protein accumulation, which is not attributable to transcriptional defects. Many components of the Rim pathway are required for correct Ena1 accumulation, but not for the accumulation of other nutrient permeases. Moreover, we observe that strains lacking components of the endosomal sorting complexes required for transport (ESCRT) pathway previously described to play a role in Rim complex formation present similar defects in Ena1 accumulation. Our results show that, in response to salt stress, a functional Rim complex via specific ESCRT interactions is required for the proper accumulation of the Ena1 protein, but not induction of the ENA1 gene.
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Affiliation(s)
- M Carmen Marqués
- Instituto de Biología Molecular y Celular de Plantas (IBMCP), Universitat Politècnica de València-Consejo Superior de Investigaciones Científicas, Avd. de los Naranjos s/n, Valencia 46022, Spain
| | - Sara Zamarbide-Forés
- Instituto de Biología Molecular y Celular de Plantas (IBMCP), Universitat Politècnica de València-Consejo Superior de Investigaciones Científicas, Avd. de los Naranjos s/n, Valencia 46022, Spain
| | - Leda Pedelini
- Instituto de Biología Molecular y Celular de Plantas (IBMCP), Universitat Politècnica de València-Consejo Superior de Investigaciones Científicas, Avd. de los Naranjos s/n, Valencia 46022, Spain
| | - Vicent Llopis-Torregrosa
- Instituto de Biología Molecular y Celular de Plantas (IBMCP), Universitat Politècnica de València-Consejo Superior de Investigaciones Científicas, Avd. de los Naranjos s/n, Valencia 46022, Spain
| | - Lynne Yenush
- Instituto de Biología Molecular y Celular de Plantas (IBMCP), Universitat Politècnica de València-Consejo Superior de Investigaciones Científicas, Avd. de los Naranjos s/n, Valencia 46022, Spain
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The role of ubiquitin/Nedd4-2 in the pathogenesis of mesial temporal lobe epilepsy. Physiol Behav 2015; 143:104-12. [PMID: 25700894 DOI: 10.1016/j.physbeh.2015.02.026] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2014] [Revised: 02/13/2015] [Accepted: 02/16/2015] [Indexed: 11/27/2022]
Abstract
Although the pathogenesis and epileptogenesis of mesial temporal lobe epilepsy (MTLE) have been studied for years, many questions remain. The ubiquitin-proteasome system (UPS) is one factor that might regulate ion channels, inflammation and neuron excitability. Nedd4-2 is an E3 ubiquitin ligase linked with ion channels and synaptic vesicle recycling. Here, we explore the role of the UPS and its E3 ligase Nedd4-2 in the pathogenesis of MTLE. Our western blot results revealed that ubiquitin and Nedd4-2 were expressed differentially in different stages of MTLE. Co-immunoprecipitation and double immunostaining results indicated that Nedd4-2 was the substrate protein of ubiquitin both in vivo and in vitro. Inhibition of the UPS aggravated the epileptogenesis of MTLE, causing early and frequent spontaneous seizures, more obvious neuron loss and aberrant mossy fiber sprouting. Inhibition of ubiquitin also enhanced the activation of Nedd4-2, and switched ion channel α-ENaC downstream. Our study is the first to report that the UPS participates in the pathogenesis of MTLE, inhibition of UPS could aggravate the epileptogenesis, and that Nedd4-2 is a critical E3 ligase involved in this process.
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Kusche-Vihrog K, Schmitz B, Brand E. Salt controls endothelial and vascular phenotype. Pflugers Arch 2014; 467:499-512. [DOI: 10.1007/s00424-014-1657-1] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2014] [Revised: 11/11/2014] [Accepted: 11/14/2014] [Indexed: 01/11/2023]
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Fu Y, Vallon V. Mineralocorticoid-induced sodium appetite and renal salt retention: evidence for common signaling and effector mechanisms. Nephron Clin Pract 2014; 128:8-16. [PMID: 25376899 DOI: 10.1159/000368264] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
An increase in renal sodium chloride (salt) retention and an increase in sodium appetite are the body's responses to salt restriction or depletion in order to restore salt balance. Renal salt retention and increased sodium appetite can also be maladaptive and sustain the pathophysiology in conditions like salt-sensitive hypertension and chronic heart failure. Here we review the central role of the mineralocorticoid aldosterone in both the increase in renal salt reabsorption and sodium appetite. We discuss the working hypothesis that aldosterone activates similar signaling and effector mechanisms in the kidney and brain, including the mineralocorticoid receptor, the serum- and glucocorticoid-induced kinase SGK1, the ubiquitin ligase NEDD4-2, and the epithelial sodium channel ENaC. The latter also mediates the gustatory salt sensing in the tongue, which is required for the manifestation of increased salt intake. Effects of aldosterone on both the brain and kidney synergize with the effects of angiotensin II. Thus, mineralocorticoids appear to induce similar molecular pathways in the kidney, brain, and possibly tongue, which could provide opportunities for more effective therapeutic interventions. Inhibition of renal salt reabsorption is compensated by stimulation of salt appetite and vice versa; targeting both mechanisms should be more effective. Inhibiting the arousal to consume salty food may improve a patient's compliance to reducing salt intake. While a better understanding of the molecular mechanisms is needed and will provide new therapeutic options, current pharmacological interventions that target both salt retention and sodium appetite include mineralocorticoid receptor antagonists and potentially inhibitors of angiotensin II and ENaC.
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Affiliation(s)
- Yiling Fu
- Department of Medicine, University of California San Diego, La Jolla, Calif., USA
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Ubiquitin-specific protease USP2-45 acts as a molecular switch to promote α2δ-1-induced downregulation of Cav1.2 channels. Pflugers Arch 2014; 467:1919-29. [PMID: 25366495 PMCID: PMC4537497 DOI: 10.1007/s00424-014-1636-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2014] [Revised: 09/26/2014] [Accepted: 09/30/2014] [Indexed: 12/20/2022]
Abstract
Availability of voltage-gated calcium channels (Cav) at the plasma membrane is paramount to maintaining the calcium homeostasis of the cell. It is proposed that the ubiquitylation/de-ubiquitylation balance regulates the density of ion channels at the cell surface. Voltage-gated calcium channels Cav1.2 have been found to be ubiquitylated under basal conditions both in vitro and in vivo. In a previous study, we have shown that Cav1.2 channels are ubiquitylated by neuronal precursor cell-expressed developmentally downregulated 4 (Nedd4-1) ubiquitin ligases, but the identity of the counterpart de-ubiquitylating enzyme remained to be elucidated. Regarding sodium and potassium channels, it has been reported that the action of the related isoform Nedd4-2 is counteracted by the ubiquitin-specific protease (USP) 2-45. In this study, we show that USP 2-45 also de-ubiquitylates Cav channels. We co-expressed USPs and Cav1.2 channels together with the accessory subunits β2 and α2δ-1, in tsA-201 and HEK-293 mammalian cell lines. Using whole-cell current recordings and surface biotinylation assays, we show that USP2-45 specifically decreases both the amplitude of Cav currents and the amount of Cav1.2 subunits inserted at the plasma membrane. Importantly, co-expression of the α2δ-1 accessory subunit is necessary to support the effect of USP2-45. We further show that USP2-45 promotes the de-ubiquitylation of both Cav1.2 and α2δ-1 subunits. Remarkably, α2δ-1, but not Cav1.2 nor β2, co-precipitated with USP2-45. These results suggest that USP2-45 binding to α2δ-1 promotes the de-ubiquitylation of both Cav1.2 and α2δ-1 subunits, in order to regulate the expression of Cav1.2 channels at the plasma membrane.
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Edinger RS, Coronnello C, Bodnar AJ, Labarca M, Bhalla V, LaFramboise WA, Benos PV, Ho J, Johnson JP, Butterworth MB. Aldosterone regulates microRNAs in the cortical collecting duct to alter sodium transport. J Am Soc Nephrol 2014; 25:2445-57. [PMID: 24744440 PMCID: PMC4214524 DOI: 10.1681/asn.2013090931] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2013] [Accepted: 02/05/2014] [Indexed: 12/26/2022] Open
Abstract
A role for microRNAs (miRs) in the physiologic regulation of sodium transport in the kidney has not been established. In this study, we investigated the potential of aldosterone to alter miR expression in mouse cortical collecting duct (mCCD) epithelial cells. Microarray studies demonstrated the regulation of miR expression by aldosterone in both cultured mCCD and isolated primary distal nephron principal cells. Aldosterone regulation of the most significantly downregulated miRs, mmu-miR-335-3p, mmu-miR-290-5p, and mmu-miR-1983 was confirmed by quantitative RT-PCR. Reducing the expression of these miRs separately or in combination increased epithelial sodium channel (ENaC)-mediated sodium transport in mCCD cells, without mineralocorticoid supplementation. Artificially increasing the expression of these miRs by transfection with plasmid precursors or miR mimic constructs blunted aldosterone stimulation of ENaC transport. Using a newly developed computational approach, termed ComiR, we predicted potential gene targets for the aldosterone-regulated miRs and confirmed ankyrin 3 (Ank3) as a novel aldosterone and miR-regulated protein. A dual-luciferase assay demonstrated direct binding of the miRs with the Ank3-3' untranslated region. Overexpression of Ank3 increased and depletion of Ank3 decreased ENaC-mediated sodium transport in mCCD cells. These findings implicate miRs as intermediaries in aldosterone signaling in principal cells of the distal kidney nephron.
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Affiliation(s)
| | | | | | | | | | | | | | | | - John P Johnson
- Renal-Electrolyte Division, Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Michael B Butterworth
- Renal-Electrolyte Division, Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
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The role of ubiquitination and sumoylation in diabetic nephropathy. BIOMED RESEARCH INTERNATIONAL 2014; 2014:160692. [PMID: 24991536 PMCID: PMC4065738 DOI: 10.1155/2014/160692] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Accepted: 05/19/2014] [Indexed: 01/14/2023]
Abstract
Diabetic nephropathy (DN) is a common and characteristic microvascular complication of diabetes; the mechanisms that cause DN have not been clarified, and the epigenetic mechanism was promised in the pathology of DN. Furthermore, ubiquitination and small ubiquitin-like modifier (SUMO) were involved in the progression of DN. MG132, as a ubiquitin proteasome, could improve renal injury by regulating several signaling pathways, such as NF-κB, TGF-β, Nrf2-oxidative stress, and MAPK. In this review, we summarize how ubiquitination and sumoylation may contribute to the pathology of DN, which may be a potential treatment strategy of DN.
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Molecular genetics of Liddle's syndrome. Clin Chim Acta 2014; 436:202-6. [PMID: 24882431 DOI: 10.1016/j.cca.2014.05.015] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2014] [Revised: 05/11/2014] [Accepted: 05/15/2014] [Indexed: 01/04/2023]
Abstract
Liddle's syndrome, an autosomal dominant form of monogenic hypertension, is characterized by salt-sensitive hypertension with early penetrance, hypokalemia, metabolic alkalosis, suppression of plasma rennin activity and aldosterone secretion, and a clear-cut response to epithelial sodium channel (ENaC) blockers but not spironolactone therapy. Our understanding of ENaCs and Na(+) transport defects has expanded greatly over the past two decades and provides detailed insight into the molecular basis of Liddle's syndrome. In this review, we offer an overview of recent advances in understanding the molecular genetics of Liddle's syndrome, involving mutation analysis, molecular mechanisms and genetic testing. The ENaC in the distal nephron is composed of α, β and γ subunits that share similar structures. Mutations associated with Liddle's syndrome are positioned in either β or γ subunits and disturb or truncate a conserved proline-rich sequence (i.e., PY motif), leading to constitutive activation of the ENaC. Genetic testing has made it possible to make accurate diagnoses and develop tailored therapies for mutation carriers.
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