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Karagiannidis AG, Theodorakopoulou MP, Pella E, Sarafidis PA, Ortiz A. Uromodulin biology. Nephrol Dial Transplant 2024; 39:1073-1087. [PMID: 38211973 PMCID: PMC11210992 DOI: 10.1093/ndt/gfae008] [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: 08/30/2023] [Indexed: 01/13/2024] Open
Abstract
Uromodulin is a kidney-specific glycoprotein which is exclusively produced by the epithelial cells lining the thick ascending limb and early distal convoluted tubule. It is currently recognized as a multifaceted player in kidney physiology and disease, with discrete roles for intracellular, urinary, interstitial and serum uromodulin. Among these, uromodulin modulates renal sodium handling through the regulation of tubular sodium transporters that reabsorb sodium and are targeted by diuretics, such as the loop diuretic-sensitive Na+-K+-2Cl- cotransporter type 2 (NKCC2) and the thiazide-sensitive Na+/Cl- cotransporter (NCC). Given these roles, the contribution of uromodulin to sodium-sensitive hypertension has been proposed. However, recent studies in humans suggest a more complex interaction between dietary sodium intake, uromodulin and blood pressure. This review presents an updated overview of the uromodulin's biology and its various roles, and focuses on the interaction between uromodulin and sodium-sensitive hypertension.
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Affiliation(s)
- Artemios G Karagiannidis
- First Department of Nephrology, Hippokration Hospital, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Marieta P Theodorakopoulou
- First Department of Nephrology, Hippokration Hospital, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Eva Pella
- First Department of Nephrology, Hippokration Hospital, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Pantelis A Sarafidis
- First Department of Nephrology, Hippokration Hospital, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Alberto Ortiz
- Department of Nephrology and Hypertension, IIS-Fundacion Jimenez Diaz UAM, Madrid, Spain
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Thielemans R, Speeckaert R, Delrue C, De Bruyne S, Oyaert M, Speeckaert MM. Unveiling the Hidden Power of Uromodulin: A Promising Potential Biomarker for Kidney Diseases. Diagnostics (Basel) 2023; 13:3077. [PMID: 37835820 PMCID: PMC10572911 DOI: 10.3390/diagnostics13193077] [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: 07/31/2023] [Revised: 09/25/2023] [Accepted: 09/26/2023] [Indexed: 10/15/2023] Open
Abstract
Uromodulin, also known as Tamm-Horsfall protein, represents the predominant urinary protein in healthy individuals. Over the years, studies have revealed compelling associations between urinary and serum concentrations of uromodulin and various parameters, encompassing kidney function, graft survival, cardiovascular disease, glucose metabolism, and overall mortality. Consequently, there has been a growing interest in uromodulin as a novel and effective biomarker with potential applications in diverse clinical settings. Reduced urinary uromodulin levels have been linked to an elevated risk of acute kidney injury (AKI) following cardiac surgery. In the context of chronic kidney disease (CKD) of different etiologies, urinary uromodulin levels tend to decrease significantly and are strongly correlated with variations in estimated glomerular filtration rate. The presence of uromodulin in the serum, attributable to basolateral epithelial cell leakage in the thick ascending limb, has been observed. This serum uromodulin level is closely associated with kidney function and histological severity, suggesting its potential as a biomarker capable of reflecting disease severity across a spectrum of kidney disorders. The UMOD gene has emerged as a prominent locus linked to kidney function parameters and CKD risk within the general population. Extensive research in multiple disciplines has underscored the biological significance of the top UMOD gene variants, which have also been associated with hypertension and kidney stones, thus highlighting the diverse and significant impact of uromodulin on kidney-related conditions. UMOD gene mutations are implicated in uromodulin-associated kidney disease, while polymorphisms in the UMOD gene show a significant association with CKD. In conclusion, uromodulin holds great promise as an informative biomarker, providing valuable insights into kidney function and disease progression in various clinical scenarios. The identification of UMOD gene variants further strengthens its relevance as a potential target for better understanding kidney-related pathologies and devising novel therapeutic strategies. Future investigations into the roles of uromodulin and regulatory mechanisms are likely to yield even more profound implications for kidney disease diagnosis, risk assessment, and management.
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Affiliation(s)
- Raïsa Thielemans
- Department of Nephrology, Ghent University Hospital, 9000 Ghent, Belgium; (R.T.); (C.D.)
| | | | - Charlotte Delrue
- Department of Nephrology, Ghent University Hospital, 9000 Ghent, Belgium; (R.T.); (C.D.)
| | - Sander De Bruyne
- Department of Laboratory Medicine, Ghent University Hospital, 9000 Ghent, Belgium; (S.D.B.); (M.O.)
| | - Matthijs Oyaert
- Department of Laboratory Medicine, Ghent University Hospital, 9000 Ghent, Belgium; (S.D.B.); (M.O.)
| | - Marijn M. Speeckaert
- Department of Nephrology, Ghent University Hospital, 9000 Ghent, Belgium; (R.T.); (C.D.)
- Research Foundation Flanders, 1000 Brussels, Belgium
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Quintanova C, Himmerkus N, Svendsen SL, von Schwerdtner O, Merkel C, Pinckert L, Mutig K, Breiderhoff T, Müller D, Günzel D, Bleich M. Unrecognized role of claudin-10b in basolateral membrane infoldings of the thick ascending limb. Ann N Y Acad Sci 2022; 1517:266-278. [PMID: 35996827 DOI: 10.1111/nyas.14882] [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: 11/29/2022]
Abstract
Claudin-10b is an important component of the tight junction in the thick ascending limb (TAL) of Henle's loop and allows paracellular sodium transport. In immunofluorescence stainings, claudin-10b-positive cells exhibited extensive extra staining of basolateral, column-like structures. The precise localization and function have so far remained elusive. In isolated cortical TAL segments from C57BL/6J mice, kidney-specific claudin-10 knockout mice (cKO), and respective litter mates (WT), we investigated the localization and protein expression and function by fluorescence microscopy and electrophysiological measurements. Ultrastructural analysis of TAL in kidney sections was performed by electron microscopy. Claudin-10b colocalized with the basolateral Na+ -K+ ATPase and the Cl- channel subunit barttin, but the lack of claudin-10b did not influence the localization or abundance of these proteins. However, the accessibility of the basolateral infolded extracellular space to ouabain or fluorescein was increased by basolateral Ca2+ removal and in the absence of claudin-10b. Ultrastructural analysis by electron microscopy revealed a widening of basolateral membrane infoldings in cKO in comparison to WT. We hypothesize that claudin-10b shapes neighboring membrane invaginations by trans interaction to stabilize and facilitate high-flux salt transport in a water-tight epithelium.
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Affiliation(s)
| | - Nina Himmerkus
- Institute of Physiology, Christian-Albrechts-University, Kiel, Germany
| | - Samuel L Svendsen
- Department of Biomedicine, Physiology, Aarhus University, Aarhus, Denmark
| | | | - Cosima Merkel
- Institute of Physiology, Christian-Albrechts-University, Kiel, Germany
| | - Lennart Pinckert
- Institute of Physiology, Christian-Albrechts-University, Kiel, Germany
| | - Kerim Mutig
- Department of Anatomy, Charité-Universitätsmedizin, Berlin, Germany
| | - Tilman Breiderhoff
- Department of Pediatrics, Division of Gastroenterology, Nephrology, and Metabolic Medicine, Charité-Universitätsmedizin, Berlin, Germany
| | - Dominik Müller
- Department of Pediatrics, Division of Gastroenterology, Nephrology, and Metabolic Medicine, Charité-Universitätsmedizin, Berlin, Germany
| | - Dorothee Günzel
- Clinical Physiology/Nutritional Medicine, Charité-Universitätsmedizin, Berlin, Germany
| | - Markus Bleich
- Institute of Physiology, Christian-Albrechts-University, Kiel, Germany
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4
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Free Cholesterol Affects the Function and Localization of Human Na +/Taurocholate Cotransporting Polypeptide (NTCP) and Organic Cation Transporter 1 (OCT1). Int J Mol Sci 2022; 23:ijms23158457. [PMID: 35955590 PMCID: PMC9368832 DOI: 10.3390/ijms23158457] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2022] [Revised: 07/25/2022] [Accepted: 07/26/2022] [Indexed: 12/15/2022] Open
Abstract
Non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH) are associated with obesity. They are accompanied by increased levels of free cholesterol in the liver. Most free cholesterol resides within the plasma membrane. We assessed the impact of adding or removing free cholesterol on the function and localization of two hepatocellular uptake transporters: the Na+/taurocholate cotransporting polypeptide (NTCP) and the organic cation transporter 1 (OCT1). We used a cholesterol-MCD complex (cholesterol) to add cholesterol and methyl-β-cyclodextrin (MCD) to remove cholesterol. Our results demonstrate that adding cholesterol decreases NTCP capacity from 132 ± 20 to 69 ± 37 µL/mg/min and OCT1 capacity from 209 ± 66 to 125 ± 26 µL/mg/min. Removing cholesterol increased NTCP and OCT1 capacity to 224 ± 65 and 279 ± 20 µL/mg/min, respectively. In addition, adding cholesterol increased the localization of NTCP within lipid rafts, while adding or removing cholesterol increased OCT1 localization in lipid rafts. These results demonstrate that increased cholesterol levels can impair NTCP and OCT1 function, suggesting that the free cholesterol content of the liver can alter bile acid and drug uptake into the liver. This could explain the increased plasma bile acid levels in NAFLD and NASH patients and potentially lead to altered drug disposition.
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Loh D, Reiter RJ. Melatonin: Regulation of Viral Phase Separation and Epitranscriptomics in Post-Acute Sequelae of COVID-19. Int J Mol Sci 2022; 23:8122. [PMID: 35897696 PMCID: PMC9368024 DOI: 10.3390/ijms23158122] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Revised: 07/09/2022] [Accepted: 07/20/2022] [Indexed: 01/27/2023] Open
Abstract
The relentless, protracted evolution of the SARS-CoV-2 virus imposes tremendous pressure on herd immunity and demands versatile adaptations by the human host genome to counter transcriptomic and epitranscriptomic alterations associated with a wide range of short- and long-term manifestations during acute infection and post-acute recovery, respectively. To promote viral replication during active infection and viral persistence, the SARS-CoV-2 envelope protein regulates host cell microenvironment including pH and ion concentrations to maintain a high oxidative environment that supports template switching, causing extensive mitochondrial damage and activation of pro-inflammatory cytokine signaling cascades. Oxidative stress and mitochondrial distress induce dynamic changes to both the host and viral RNA m6A methylome, and can trigger the derepression of long interspersed nuclear element 1 (LINE1), resulting in global hypomethylation, epigenetic changes, and genomic instability. The timely application of melatonin during early infection enhances host innate antiviral immune responses by preventing the formation of "viral factories" by nucleocapsid liquid-liquid phase separation that effectively blockades viral genome transcription and packaging, the disassembly of stress granules, and the sequestration of DEAD-box RNA helicases, including DDX3X, vital to immune signaling. Melatonin prevents membrane depolarization and protects cristae morphology to suppress glycolysis via antioxidant-dependent and -independent mechanisms. By restraining the derepression of LINE1 via multifaceted strategies, and maintaining the balance in m6A RNA modifications, melatonin could be the quintessential ancient molecule that significantly influences the outcome of the constant struggle between virus and host to gain transcriptomic and epitranscriptomic dominance over the host genome during acute infection and PASC.
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Affiliation(s)
- Doris Loh
- Independent Researcher, Marble Falls, TX 78654, USA;
| | - Russel J. Reiter
- Department of Cell Systems and Anatomy, UT Health San Antonio, San Antonio, TX 78229, USA
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6
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The cellular prion protein interacts with and promotes the activity of Na,K-ATPases. PLoS One 2021; 16:e0258682. [PMID: 34847154 PMCID: PMC8631662 DOI: 10.1371/journal.pone.0258682] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Accepted: 10/02/2021] [Indexed: 12/23/2022] Open
Abstract
The prion protein (PrP) is best known for its ability to cause fatal neurodegenerative diseases in humans and animals. Here, we revisited its molecular environment in the brain using a well-developed affinity-capture mass spectrometry workflow that offers robust relative quantitation. The analysis confirmed many previously reported interactions. It also pointed toward a profound enrichment of Na,K-ATPases (NKAs) in proximity to cellular PrP (PrPC). Follow-on work validated the interaction, demonstrated partial co-localization of the ATP1A1 and PrPC, and revealed that cells exposed to cardiac glycoside (CG) inhibitors of NKAs exhibit correlated changes to the steady-state levels of both proteins. Moreover, the presence of PrPC was observed to promote the ion uptake activity of NKAs in a human co-culture paradigm of differentiated neurons and glia cells, and in mouse neuroblastoma cells. Consistent with this finding, changes in the expression of 5’-nucleotidase that manifest in wild-type cells in response to CG exposure can also be observed in untreated PrPC-deficient cells. Finally, the endoproteolytic cleavage of the glial fibrillary acidic protein, a hallmark of late-stage prion disease, can also be induced by CGs, raising the prospect that a loss of NKA activity may contribute to the pathobiology of prion diseases.
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Wang Q, Cao Z, Du B, Zhang Q, Chen L, Wang X, Yuan Z, Wang P, He R, Shan J, Zhao Y, Miao L. Membrane contact site-dependent cholesterol transport regulates Na +/K +-ATPase polarization and spermiogenesis in Caenorhabditis elegans. Dev Cell 2021; 56:1631-1645.e7. [PMID: 34051143 DOI: 10.1016/j.devcel.2021.05.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 03/08/2021] [Accepted: 05/06/2021] [Indexed: 10/21/2022]
Abstract
Spermiogenesis in nematodes is a process whereby round and quiescent spermatids differentiate into asymmetric and crawling spermatozoa. The molecular mechanism underlying this symmetry breaking remains uncharacterized. In this study, we revealed that sperm-specific Na+/K+-ATPase (NKA) is evenly distributed on the plasma membrane (PM) of Caenorhabditis elegans spermatids but is translocated to and subsequently enters the invaginated membrane of the spermatozoa cell body during sperm activation. The polarization of NKA depends on the transport of cholesterol from the PM to membranous organelles (MOs) via membrane contact sites (MCSs). The inositol 5-phosphatase CIL-1 and the MO-localized PI4P phosphatase SAC-1 may mediate PI4P metabolism to drive cholesterol countertransport via sterol/lipid transport proteins through MCSs. Furthermore, the NKA function is required for C. elegans sperm motility and reproductive success. Our data imply that the lipid dynamics mediated by MCSs might play crucial roles in the establishment of cell polarity. eGraphical abstract.
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Affiliation(s)
- Qiushi Wang
- Key Laboratory of RNA Biology, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zheng Cao
- Key Laboratory of RNA Biology, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China.
| | - Baochen Du
- Key Laboratory of RNA Biology, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Qi Zhang
- Key Laboratory of RNA Biology, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Lianwan Chen
- Key Laboratory of RNA Biology, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Xia Wang
- Key Laboratory of RNA Biology, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Zhiheng Yuan
- Key Laboratory of RNA Biology, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Peng Wang
- Key Laboratory of RNA Biology, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Ruijun He
- Key Laboratory of RNA Biology, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Jin Shan
- Key Laboratory of RNA Biology, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yanmei Zhao
- Key Laboratory of RNA Biology, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China.
| | - Long Miao
- Key Laboratory of RNA Biology, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China; Center for Biological Imaging, Core Facilities for Protein Science, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China.
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8
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Kumar SA, Albrecht T, Kauzál O, Tomášek O. No Evidence for Trade-Offs Between Lifespan, Fecundity, and Basal Metabolic Rate Mediated by Liver Fatty Acid Composition in Birds. Front Cell Dev Biol 2021; 9:638501. [PMID: 33869185 PMCID: PMC8045231 DOI: 10.3389/fcell.2021.638501] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2020] [Accepted: 02/23/2021] [Indexed: 01/03/2023] Open
Abstract
The fatty acid composition of biological membranes has been hypothesised to be a key molecular adaptation associated with the evolution of metabolic rates, ageing, and life span – the basis of the membrane pacemaker hypothesis (MPH). MPH proposes that highly unsaturated membranes enhance cellular metabolic processes while being more prone to oxidative damage, thereby increasing the rates of metabolism and ageing. MPH could, therefore, provide a mechanistic explanation for trade-offs between longevity, fecundity, and metabolic rates, predicting that short-lived species with fast metabolic rates and higher fecundity would have greater levels of membrane unsaturation. However, previous comparative studies testing MPH provide mixed evidence regarding the direction of covariation between fatty acid unsaturation and life span or metabolic rate. Moreover, some empirical studies suggest that an n-3/n-6 PUFA ratio or the fatty acid chain length, rather than the overall unsaturation, could be the key traits coevolving with life span. In this study, we tested the coevolution of liver fatty acid composition with maximum life span, annual fecundity, and basal metabolic rate (BMR), using a recently published data set comprising liver fatty acid composition of 106 avian species. While statistically controlling for the confounding effects of body mass and phylogeny, we found no support for long life span evolving with low fatty acid unsaturation and only very weak support for fatty acid unsaturation acting as a pacemaker of BMR. Moreover, our analysis provided no evidence for the previously reported links between life span and n-3 PUFA/total PUFA or MUFA proportion. Our results rather suggest that long life span evolves with long-chain fatty acids irrespective of their degree of unsaturation as life span was positively associated with at least one long-chain fatty acid of each type (i.e., SFA, MUFA, n-6 PUFA, and n-3 PUFA). Importantly, maximum life span, annual fecundity, and BMR were associated with different fatty acids or fatty acid indices, indicating that longevity, fecundity, and BMR coevolve with different aspects of fatty acid composition. Therefore, in addition to posing significant challenges to MPH, our results imply that fatty acid composition does not pose an evolutionary constraint underpinning life-history trade-offs at the molecular level.
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Affiliation(s)
- Sampath A Kumar
- Institute of Vertebrate Biology, Czech Academy of Sciences, Brno, Czechia.,Department of Botany and Zoology, Faculty of Science, Masaryk University, Brno, Czechia
| | - Tomáš Albrecht
- Institute of Vertebrate Biology, Czech Academy of Sciences, Brno, Czechia.,Department of Zoology, Faculty of Science, Charles University, Prague, Czechia
| | - Ondřej Kauzál
- Institute of Vertebrate Biology, Czech Academy of Sciences, Brno, Czechia.,Department of Ecology, Faculty of Science, Charles University, Prague, Czechia
| | - Oldřich Tomášek
- Institute of Vertebrate Biology, Czech Academy of Sciences, Brno, Czechia.,Department of Botany and Zoology, Faculty of Science, Masaryk University, Brno, Czechia
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Differential expression of two ATPases revealed by lipid raft isolation from gills of euryhaline teleosts with different salinity preferences. Comp Biochem Physiol B Biochem Mol Biol 2021; 253:110562. [PMID: 33453387 DOI: 10.1016/j.cbpb.2021.110562] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2020] [Revised: 12/29/2020] [Accepted: 01/10/2021] [Indexed: 12/12/2022]
Abstract
In euryhaline teleosts, Na+, K+-ATPase (NKA) and V-type H + -ATPase A (VHA A) are important ion-transporters located in cell membrane. Lipid rafts (LR) are plasma membrane microdomains enriched in cholesterol, sphingolipids, and proteins (e.g., flotillin). Flotillin is a LR-associated protein, commonly used as the LR marker. Previous mammalian studies showed that LR may play a crucial role in ion exchanges. Meanwhile, studies on mammals and rainbow trout showed that NKA were found to be present mainly in LR. However, little is known about LR in fish. Therefore, the present study aimed to investigate the involvement of branchial LR in osmoregulation of tilapia and milkfish, two euryhaline teleosts with different salinity preferences, by (i) extracting LR from the gills of euryhaline teleosts; (ii) detecting the abundance of LR marker protein (flotillin-2) and ion-transporters (NKA and VHA A) in branchial LR and non-LR of fresh water- and seawater-acclimated milkfish and tilapia. The results indicated that the protein abundance of LR marker, flotillin-2, changed with environmental salinities in branchial LR of tilapia. In addition, flotillin-2 and NKA were only found in LR in both tilapia and milkfish gills, while VHA A were mainly present in non-LR. Relative protein abundance of NKA was found to be significantly higher in gills of freshwater milkfish and seawater tilapia, while VHA A was significantly higher in gills of freshwater tilapia and milkfish. This study illustrated differential distribution and salinity-dependent expression of NKA and VHA A in cell membrane of gill tissues of euryhaline teleosts with different salinity preferences.
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Mu P, Liu Y, Jiang S, Gao J, Sun S, Li L, Gao D. Glial cell line-derived neurotrophic factor alters lipid composition and protein distribution in MPP+-injured differentiated SH-SY5Y cells. J Cell Physiol 2020; 235:9347-9360. [PMID: 32356318 DOI: 10.1002/jcp.29738] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Revised: 03/28/2020] [Accepted: 04/18/2020] [Indexed: 12/13/2022]
Abstract
Parkinson's disease (PD) is a neurodegenerative disease characterized by progressive loss of dopaminergic neurons in the substantia nigra and striatum. Glial cell line-derived neurotrophic factor (GDNF) can effectively promote the differentiation and survival of many types of neurons, especially dopaminergic neurons, suggesting it could be a treatment for PD. Lipid rafts are highly dynamic cell membrane domains that contain numerous signal protein receptors, providing an important platform for signal transduction. Compelling evidence indicates that alterations in lipid rafts are associated with PD, and some studies have reported that GDNF can regulate the expression of caveolin-1, a lipid raft-marker protein. However, the precise effects of GDNF on lipid rafts remain unknown. We developed a cellular PD model, purified detergent-resistant membranes (membrane rafts), and performed proteomic and lipid metabolomics analyses to examine changes in lipid rafts after GDNF treatment. The results showed considerable protein and lipid alterations in response to GDNF, especially altered levels of dopamine-β-hydroxylase, heat shock 70 kDa protein, neural cell adhesion molecule, cytoskeletal proteins, and long-chain polysaturated/unsaturated fatty acids. These findings reveal a new avenue to explore the relationships between GDNF, lipid rafts, and PD and support the hypothesis that GDNF may be a useful treatment for PD.
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Affiliation(s)
- Peipei Mu
- Jiangsu Key Laboratory of Brian Disease and Bioinformation, Research Center for Biochemistry and Molecular Biology, Xuzhou Medical University, Xuzhou, Jiangsu, China.,School of Nursing and Midwifery, Jiangsu College of Nursing, Huaian, Jiangsu, China.,Department of Neurobiology, Xuzhou Key Laboratory of Neurobiology, Xuzhou Medical University, Xuzhou, Jiangsu, China.,School of Nursing, Xuzhou Medical University, Xuzhou, Jiangsu, China
| | - Yuting Liu
- Laboratory of Clinical and Experimental Pathology, Xuzhou Medical University, Xuzhou, Jiangsu, China
| | - Shimin Jiang
- Laboratory of Clinical and Experimental Pathology, Xuzhou Medical University, Xuzhou, Jiangsu, China
| | - Jin Gao
- Department of Neurobiology, Xuzhou Key Laboratory of Neurobiology, Xuzhou Medical University, Xuzhou, Jiangsu, China
| | - Shen Sun
- Department of Histology and Embryology, Xuzhou Medical University, Xuzhou, Jiangsu, China
| | - Li Li
- Jiangsu Key Laboratory of Brian Disease and Bioinformation, Research Center for Biochemistry and Molecular Biology, Xuzhou Medical University, Xuzhou, Jiangsu, China.,Laboratory of Clinical and Experimental Pathology, Xuzhou Medical University, Xuzhou, Jiangsu, China.,Department of Pathophysiology, School of the Basic Medicine, Xuzhou Medical University, Xuzhou, Jiangsu, China
| | - Dianshuai Gao
- Department of Neurobiology, Xuzhou Key Laboratory of Neurobiology, Xuzhou Medical University, Xuzhou, Jiangsu, China
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11
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Tiu AC, Yang J, Asico LD, Konkalmatt P, Zheng X, Cuevas S, Wang X, Lee H, Mazhar M, Felder RA, Jose PA, Villar VAM. Lipid rafts are required for effective renal D 1 dopamine receptor function. FASEB J 2020; 34:6999-7017. [PMID: 32259353 DOI: 10.1096/fj.201902710rr] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Revised: 03/05/2020] [Accepted: 03/17/2020] [Indexed: 12/13/2022]
Abstract
Effective receptor signaling is anchored on the preferential localization of the receptor in lipid rafts, which are plasma membrane platforms replete with cholesterol and sphingolipids. We hypothesized that the dopamine D1 receptor (D1 R) contains structural features that allow it to reside in lipid rafts for its activity. Mutation of C347 palmitoylation site and Y218 of a newly identified Cholesterol Recognition Amino Acid Consensus motif resulted in the exclusion of D1 R from lipid rafts, blunted cAMP response, impaired sodium transport, and increased oxidative stress in renal proximal tubule cells (RPTCs). Kidney-restricted silencing of Drd1 in C57BL/6J mice increased blood pressure (BP) that was normalized by renal tubule-restricted rescue with D1 R-wild-type but not the mutant D1 R 347A that lacks a palmitoylation site. Kidney-restricted disruption of lipid rafts by β-MCD jettisoned the D1 R from the brush border, decreased sodium excretion, and increased oxidative stress and BP in C57BL/6J mice. Deletion of the PX domain of the novel D1 R-binding partner sorting nexin 19 (SNX19) resulted in D1 R partitioning solely to non-raft domains, while silencing of SNX19 impaired D1 R function in RPTCs. Kidney-restricted silencing of Snx19 resulted in hypertension in C57BL/6J mice. Our results highlight the essential role of lipid rafts for effective D1 R signaling.
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Affiliation(s)
- Andrew C Tiu
- Division of Renal Diseases & Hypertension, Department of Medicine, The George Washington University School of Medicine & Health Sciences, Washington, DC, USA.,Department of Medicine, Einstein Medical Center, Philadelphia, PA, USA
| | - Jian Yang
- Department of Clinical Nutrition, The Third Affiliated Hospital of Chongqing Medical University, Chongqing, P.R. China
| | - Laureano D Asico
- Division of Renal Diseases & Hypertension, Department of Medicine, The George Washington University School of Medicine & Health Sciences, Washington, DC, USA
| | - Prasad Konkalmatt
- Division of Renal Diseases & Hypertension, Department of Medicine, The George Washington University School of Medicine & Health Sciences, Washington, DC, USA
| | - Xiaoxu Zheng
- Division of Renal Diseases & Hypertension, Department of Medicine, The George Washington University School of Medicine & Health Sciences, Washington, DC, USA
| | - Santiago Cuevas
- Division of Renal Diseases & Hypertension, Department of Medicine, The George Washington University School of Medicine & Health Sciences, Washington, DC, USA
| | - Xiaoyan Wang
- Division of Renal Diseases & Hypertension, Department of Medicine, The George Washington University School of Medicine & Health Sciences, Washington, DC, USA
| | - Hewang Lee
- Kidney Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD, USA
| | - Momina Mazhar
- Division of Renal Diseases & Hypertension, Department of Medicine, The George Washington University School of Medicine & Health Sciences, Washington, DC, USA
| | - Robin A Felder
- Department of Pathology, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Pedro A Jose
- Division of Renal Diseases & Hypertension, Department of Medicine, The George Washington University School of Medicine & Health Sciences, Washington, DC, USA.,Department of Pharmacology/Physiology, The George Washington University School of Medicine & Health Sciences, Washington, DC, USA
| | - Van Anthony M Villar
- Division of Renal Diseases & Hypertension, Department of Medicine, The George Washington University School of Medicine & Health Sciences, Washington, DC, USA
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12
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da Silva Xavier A, da Silva FP, Vidigal PMP, Lima TTM, de Souza FO, Alfenas-Zerbini P. Genomic and biological characterization of a new member of the genus Phikmvvirus infecting phytopathogenic Ralstonia bacteria. Arch Virol 2018; 163:3275-3290. [DOI: 10.1007/s00705-018-4006-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Accepted: 08/10/2018] [Indexed: 02/07/2023]
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13
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Maruyama H, Taguchi A, Nishikawa Y, Guili C, Mikame M, Nameta M, Yamaguchi Y, Ueno M, Imai N, Ito Y, Nakagawa T, Narita I, Ishii S. Medullary thick ascending limb impairment in the Gla tmTg(CAG-A4GALT) Fabry model mice. FASEB J 2018; 32:4544-4559. [PMID: 29553830 PMCID: PMC6071062 DOI: 10.1096/fj.201701374r] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
A main feature of Fabry disease is nephropathy, with polyuria an early manifestation; however, the mechanism that underlies polyuria and affected tubules is unknown. To increase globotriaosylceramide (Gb3) levels, we previously crossbred asymptomatic Glatm mice with transgenic mice that expressed human Gb3 synthase (A4GALT) and generated the GlatmTg(CAG-A4GALT) symptomatic Fabry model mice. Additional analyses revealed that these mice exhibit polyuria and renal dysfunction without remarkable glomerular damage. In the present study, we investigated the mechanism of polyuria and renal dysfunction in these mice. Gb3 accumulation was mostly detected in the medulla; medullary thick ascending limbs (mTALs) were the most vacuolated tubules. mTAL cells contained lamellar bodies and had lost their characteristic structure (i.e., extensive infolding and numerous elongated mitochondria). Decreased expression of the major molecules—Na+-K+-ATPase, uromodulin, and Na+-K+-2Cl− cotransporter—that are involved in Na+ reabsorption in mTALs and the associated loss of urine-concentrating ability resulted in progressive water- and salt-loss phenotypes. GlatmTg(CAG-A4GALT) mice exhibited fibrosis around mTALs and renal dysfunction. These and other features were consistent with pathologic findings in patients with Fabry disease. Results demonstrate that mTAL dysfunction causes polyuria and renal impairment and contributes to the pathophysiology of Fabry nephropathy.—Maruyama, H., Taguchi, A., Nishikawa, Y., Guili, C., Mikame, M., Nameta, M., Yamaguchi, Y., Ueno, M., Imai, N., Ito, Y., Nakagawa, T., Narita, I., Ishii, S. Medullary thick ascending limb impairment in the GlatmTg(CAG-A4GALT) Fabry model mice.
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Affiliation(s)
- Hiroki Maruyama
- Department of Clinical Nephroscience, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Atsumi Taguchi
- Department of Clinical Nephroscience, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan.,Department of Matrix Medicine, Faculty of Medicine, Oita University, Yufu, Japan
| | - Yuji Nishikawa
- Division of Tumor Pathology, Department of Pathology, Asahikawa Medical University, Asahikawa, Japan
| | - Chu Guili
- Department of Clinical Nephroscience, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Mariko Mikame
- Department of Clinical Nephroscience, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Masaaki Nameta
- Electron Microscope Core Facility, Niigata University, Niigata, Japan
| | | | - Mitsuhiro Ueno
- University Health Center, Joetsu University of Education, Joetsu, Japan
| | - Naofumi Imai
- Division of Clinical Nephrology and Rheumatology, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Yumi Ito
- Department of Health Promotion Medicine, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | | | - Ichiei Narita
- Division of Clinical Nephrology and Rheumatology, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Satoshi Ishii
- Department of Matrix Medicine, Faculty of Medicine, Oita University, Yufu, Japan.,GlycoPharma Corporation, Oita, Japan
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Devuyst O, Olinger E, Rampoldi L. Uromodulin: from physiology to rare and complex kidney disorders. Nat Rev Nephrol 2017; 13:525-544. [PMID: 28781372 DOI: 10.1038/nrneph.2017.101] [Citation(s) in RCA: 192] [Impact Index Per Article: 27.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Uromodulin (also known as Tamm-Horsfall protein) is exclusively produced in the kidney and is the most abundant protein in normal urine. The function of uromodulin remains elusive, but the available data suggest that this protein might regulate salt transport, protect against urinary tract infection and kidney stones, and have roles in kidney injury and innate immunity. Interest in uromodulin was boosted by genetic studies that reported involvement of the UMOD gene, which encodes uromodulin, in a spectrum of rare and common kidney diseases. Rare mutations in UMOD cause autosomal dominant tubulointerstitial kidney disease (ADTKD), which leads to chronic kidney disease (CKD). Moreover, genome-wide association studies have identified common variants in UMOD that are strongly associated with risk of CKD and also with hypertension and kidney stones in the general population. These findings have opened up a new field of kidney research. In this Review we summarize biochemical, physiological, genetic and pathological insights into the roles of uromodulin; the mechanisms by which UMOD mutations cause ADTKD, and the association of common UMOD variants with complex disorders.
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Affiliation(s)
- Olivier Devuyst
- Institute of Physiology, University of Zurich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
| | - Eric Olinger
- Institute of Physiology, University of Zurich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
| | - Luca Rampoldi
- Division of Genetics and Cell Biology, IRCCS San Raffaele Scientific Institute, Via Olgettina 58, 20132 Milan, Italy
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15
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Yang CW, Chang HY, Hsu HY, Lee YZ, Chang HS, Chen IS, Lee SJ. Identification of anti-viral activity of the cardenolides, Na +/K +-ATPase inhibitors, against porcine transmissible gastroenteritis virus. Toxicol Appl Pharmacol 2017; 332:129-137. [PMID: 28438630 PMCID: PMC7103123 DOI: 10.1016/j.taap.2017.04.017] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Revised: 03/17/2017] [Accepted: 04/17/2017] [Indexed: 01/06/2023]
Abstract
A series of naturally occurring cardenolides that exhibit potent anti-transmissible gastroenteritis virus (TGEV) activity in swine testicular (ST) cells has been identified. In an immunofluorescence assay, these cardenolides were found to diminish the expressions of TGEV nucleocapsid and spike protein, which was used as an indication for viral replication; block TGEV infection induced apoptosis and cytopathic effects; and impart the same trend of inhibitory activity against Na+/K+-ATPase as for anti-TGEV activity. The viral titer inhibition was found to take place in a dose-dependent manner. Knocking down expression of Na+/K+-ATPase, the cellular receptor of cardenolides, in ST cells was found to significantly impair the susceptibility of ST cells to TGEV infectivity. Thus, we have identified Na+/K+-ATPase as an anti-viral drug target and its antagonists, cardenolides, a novel class of anti- TGEV agents.
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Affiliation(s)
- Cheng-Wei Yang
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Miaoli 35053, Taiwan, ROC
| | - Hsin-Yu Chang
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Miaoli 35053, Taiwan, ROC
| | - Hsing-Yu Hsu
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Miaoli 35053, Taiwan, ROC
| | - Yue-Zhi Lee
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Miaoli 35053, Taiwan, ROC
| | - Hsun-Shuo Chang
- School of Pharmacy, College of Pharmacy, Kaohsiung Medical University, Kaohsiung 807, Taiwan, ROC
| | - Ih-Sheng Chen
- School of Pharmacy, College of Pharmacy, Kaohsiung Medical University, Kaohsiung 807, Taiwan, ROC
| | - Shiow-Ju Lee
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Miaoli 35053, Taiwan, ROC.
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16
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Na+/K+-ATPase β1-subunit is recruited in Na-K-2Cl co-transporter isoform 2 multiprotein complexes in rat kidneys: possible role in blood pressure regulation. J Hypertens 2016; 32:1842-53. [PMID: 24927069 DOI: 10.1097/hjh.0000000000000258] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
OBJECTIVE The progression from prehypertensive to hypertensive state in spontaneous hypertensive rats (SHRs) is accompanied by a significant increase in membrane expression of Na-K-2Cl co-transporter isoform 2 (NKCC2), suggesting that the altered NKCC2 trafficking and activity are directly related with the development of hypertension in this strain. The aim of this work is to gain insights on the molecular mechanism that underlies this phenomenon. METHODS We performed a comparative analysis of NKCC2 multiprotein complexes (MPCs) in the kidney of SHRs versus Wistar Kyoto rats by Blue Native difference gel electrophoresis combined with mass spectrometry. RESULTS We found that the recruitment of the β-subunit isoform 1 of the Na(+)-K(+)-ATPase (β1NK) in NKCC2 MPCs was significantly increased in the kidneys of SHR compared with Wistar Kyoto rat control strain. Co-immunoprecipitation experiments showed that β1NK actually interacts with NKCC2 in the native tissue. The analysis of the physiological role of β1NK-NKCC2 interaction in human embryonic kidney cells showed that β1NK increased the steady-state membrane expression and activity of NKCC2 enhancing NKCC2 trafficking toward the plasma membrane. CONCLUSION We identify a new NKCC2-interacting partner involved in the modulation of NKCC2 intracellular trafficking and possibly involved in the regulation of blood pressure.
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17
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Perspectives on the membrane fatty acid unsaturation/pacemaker hypotheses of metabolism and aging. Chem Phys Lipids 2015; 191:48-60. [PMID: 26291495 DOI: 10.1016/j.chemphyslip.2015.08.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Revised: 08/10/2015] [Accepted: 08/12/2015] [Indexed: 12/27/2022]
Abstract
The membrane pacemaker hypotheses of metabolism and aging are distinct, but interrelated hypotheses positing that increases in unsaturation of lipids within membranes are correlated with increasing basal metabolic rate and decreasing longevity, respectively. The two hypotheses each have evidence that either supports or contradicts them, but consensus has failed to emerge. In this review, we identify sources of weakness of previous studies supporting and contradicting these hypotheses and suggest different methods and lines of inquiry. The link between fatty acyl composition of membranes and membrane-bound protein activity is a central tenet of the membrane pacemaker hypothesis of metabolism, but the mechanism by which unsaturation would change protein activity is not well defined and, whereas fatty acid desaturases have been put forward by some as the mechanism behind evolutionary differences in fatty acyl composition of phospholipids among organisms, there have been no studies to differentiate whether desaturases have been more affected by natural selection on aging and metabolic rate than have elongases or acyltransferases. Past analyses have been hampered by potentially incorrect estimates of the peroxidizability of lipids and longevity of study animals, and by the confounding effect of phylogeny. According to some authors, body mass may also be a confounding effect that should be taken into account, though this is not universally accepted. Further research on this subject should focus more on mechanisms and take weaknesses of past studies into account.
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18
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Investigation of membrane protein-protein interactions using correlative FRET-PLA. Biotechniques 2014; 57:188-91, 193-8. [PMID: 25312088 DOI: 10.2144/000114215] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2014] [Accepted: 09/05/2014] [Indexed: 11/23/2022] Open
Abstract
Fluorescence resonance energy transfer (FRET) analysis and the recently developed proximity ligation assay (PLA) are widely used to study protein-protein interactions in situ. We have developed correlative FRET-PLA to monitor interactions between membrane proteins that frequently cause problems in confirmatory co-immunoprecipitation assays. Correlative FRET-PLA is particularly aimed at delivering robust and reliable results and is useful for investigating protein-protein interactions.
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19
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Dathe C, Daigeler AL, Seifert W, Jankowski V, Mrowka R, Kalis R, Wanker E, Mutig K, Bachmann S, Paliege A. Annexin A2 mediates apical trafficking of renal Na⁺-K⁺-2Cl⁻ cotransporter. J Biol Chem 2014; 289:9983-97. [PMID: 24526686 DOI: 10.1074/jbc.m113.540948] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The furosemide-sensitive Na(+)-K(+)-2Cl(-) cotransporter (NKCC2) is responsible for urine concentration and helps maintain systemic salt homeostasis. Its activity depends on trafficking to, and insertion into, the apical membrane, as well as on phosphorylation of conserved N-terminal serine and threonine residues. Vasopressin (AVP) signaling via PKA and other kinases activates NKCC2. Association of NKCC2 with lipid rafts facilitates its AVP-induced apical translocation and activation at the surface. Lipid raft microdomains typically serve as platforms for membrane proteins to facilitate their interactions with other proteins, but little is known about partners that interact with NKCC2. Yeast two-hybrid screening identified an interaction between NKCC2 and the cytosolic protein, annexin A2 (AnxA2). Annexins mediate lipid raft-dependent trafficking of transmembrane proteins, including the AVP-regulated water channel, aquaporin 2. Here, we demonstrate that AnxA2, which binds to phospholipids in a Ca(2+)-dependent manner and may organize microdomains, is codistributed with NKCC2 to promote its apical translocation in response to AVP stimulation and low chloride hypotonic stress. NKCC2 and AnxA2 interact in a phosphorylation-dependent manner. Phosphomimetic AnxA2 carrying a mutant phosphoacceptor (AnxA2-Y24D-GFP) enhanced surface expression and raft association of NKCC2 by 5-fold upon low chloride hypotonic stimulation, whereas AnxA2-Y24A-GFP and PKC-dependent AnxA2-S26D-GFP did not. As the AnxA2 effect involved only nonphosphorylated NKCC2, it appears to affect NKCC2 trafficking. Overexpression or knockdown experiments further supported the role of AnxA2 in the apical translocation and surface expression of NKCC2. In summary, this study identifies AnxA2 as a lipid raft-associated trafficking factor for NKCC2 and provides mechanistic insight into the regulation of this essential cotransporter.
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Affiliation(s)
- Christin Dathe
- From the Department of Anatomy, Charité-Universitätsmedizin Berlin, 10115 Berlin
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20
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de Juan-Sanz J, Núñez E, Villarejo-López L, Pérez-Hernández D, Rodriguez-Fraticelli AE, López-Corcuera B, Vázquez J, Aragón C. Na+/K+-ATPase is a new interacting partner for the neuronal glycine transporter GlyT2 that downregulates its expression in vitro and in vivo. J Neurosci 2013; 33:14269-81. [PMID: 23986260 PMCID: PMC6618510 DOI: 10.1523/jneurosci.1532-13.2013] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2013] [Revised: 07/09/2013] [Accepted: 07/18/2013] [Indexed: 01/16/2023] Open
Abstract
The neuronal glycine transporter GlyT2 plays a fundamental role in the glycinergic neurotransmission by recycling the neurotransmitter to the presynaptic terminal. GlyT2 is the main supplier of glycine for vesicle refilling, a process that is absolutely necessary to preserve quantal glycine content in synaptic vesicles. Alterations in GlyT2 activity modify glycinergic neurotransmission and may underlie several neuromuscular disorders, such as hyperekplexia, myoclonus, dystonia, and epilepsy. Indeed, mutations in the gene encoding GlyT2 are the main presynaptic cause of hyperekplexia in humans and produce congenital muscular dystonia type 2 (CMD2) in Belgian Blue cattle. GlyT2 function is strictly coupled to the sodium electrochemical gradient actively generated by the Na+/K+-ATPase (NKA). GlyT2 cotransports 3Na+/Cl-/glycine generating large rises of Na+ inside the presynaptic terminal that must be efficiently reduced by the NKA to preserve Na+ homeostasis. In this work, we have used high-throughput mass spectrometry to identify proteins interacting with GlyT2 in the CNS. NKA was detected as a putative candidate and through reciprocal coimmunoprecipitations and immunocytochemistry analyses the association between GlyT2 and NKA was confirmed. NKA mainly interacts with the raft-associated active pool of GlyT2, and low and high levels of the specific NKA ligand ouabain modulate the endocytosis and total expression of GlyT2 in neurons. The ouabain-mediated downregulation of GlyT2 also occurs in vivo in two different systems: zebrafish embryos and adult rats, indicating that this NKA-mediated regulatory mechanism is evolutionarily conserved and may play a relevant role in the physiological control of inhibitory glycinergic neurotransmission.
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Affiliation(s)
- Jaime de Juan-Sanz
- Centro de Biología Molecular Severo Ochoa, Universidad Autónoma de Madrid, Consejo Superior de Investigaciones Científicas, 28049 Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Raras, ISCIII, 46010 Valencia, Spain
- IdiPAZ-Hospital Universitario La Paz, 28046 Madrid, Spain
| | - Enrique Núñez
- Centro de Biología Molecular Severo Ochoa, Universidad Autónoma de Madrid, Consejo Superior de Investigaciones Científicas, 28049 Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Raras, ISCIII, 46010 Valencia, Spain
- IdiPAZ-Hospital Universitario La Paz, 28046 Madrid, Spain
| | - Lucía Villarejo-López
- Centro de Biología Molecular Severo Ochoa, Universidad Autónoma de Madrid, Consejo Superior de Investigaciones Científicas, 28049 Madrid, Spain
| | | | - Alejo E. Rodriguez-Fraticelli
- Centro de Biología Molecular Severo Ochoa, Universidad Autónoma de Madrid, Consejo Superior de Investigaciones Científicas, 28049 Madrid, Spain
| | - Beatriz López-Corcuera
- Centro de Biología Molecular Severo Ochoa, Universidad Autónoma de Madrid, Consejo Superior de Investigaciones Científicas, 28049 Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Raras, ISCIII, 46010 Valencia, Spain
- IdiPAZ-Hospital Universitario La Paz, 28046 Madrid, Spain
| | - Jesús Vázquez
- Centro Nacional de Investigaciones Cardiovasculares, 28029 Madrid, Spain, and
| | - Carmen Aragón
- Centro de Biología Molecular Severo Ochoa, Universidad Autónoma de Madrid, Consejo Superior de Investigaciones Científicas, 28049 Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Raras, ISCIII, 46010 Valencia, Spain
- IdiPAZ-Hospital Universitario La Paz, 28046 Madrid, Spain
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Dietrich A, Mathia S, Kaminski H, Mutig K, Rosenberger C, Mrowka R, Bachmann S, Paliege A. Chronic activation of vasopressin V2 receptor signalling lowers renal medullary oxygen levels in rats. Acta Physiol (Oxf) 2013; 207:721-31. [PMID: 23347696 DOI: 10.1111/apha.12067] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2012] [Revised: 12/27/2012] [Accepted: 01/17/2013] [Indexed: 12/17/2022]
Abstract
AIM In the present study, we aimed to elucidate the effects of chronic vasopressin administration on renal medullary oxygen levels. METHODS Adult Sprague Dawley or vasopressin-deficient Brattleboro rats were treated with the vasopressin V2 receptor agonist, desmopressin (5 ng/h; 3d), or its vehicle via osmotic minipumps. Immunostaining for pimonidazole and the transcription factor HIF-1α (hypoxia-inducible factor-1α) were used to identify hypoxic areas. Activation of HIF-target gene expression following desmopressin treatment was studied by microarray analysis. RESULTS Pimonidazole staining was detected in the outer and inner medulla of desmopressin-treated rats, whereas staining in control animals was weak or absent. HIF-1α immunostaining demonstrated nuclear accumulation in the papilla of desmopressin-treated animals, whereas no staining was observed in the controls. Gene expression analysis revealed significant enrichment of HIF-target genes in the group of desmopressin-regulated gene products (P = 2.6*10(-21) ). Regulated products included insulin-like growth factor binding proteins 1 and 3, angiopoietin 2, fibronectin, cathepsin D, hexokinase 2 and cyclooxygenase 2. CONCLUSION Our results demonstrate that an activation of the renal urine concentrating mechanism by desmopressin causes renal medullary hypoxia and an upregulation of hypoxia-inducible gene expression.
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Affiliation(s)
- A. Dietrich
- Department of Anatomy; Charité-Universitätsmedizin Berlin; Berlin; Germany
| | - S. Mathia
- Department of Nephrology; Charité-Universitätsmedizin Berlin; Berlin; Germany
| | - H. Kaminski
- Department of Anatomy; Charité-Universitätsmedizin Berlin; Berlin; Germany
| | - K. Mutig
- Department of Anatomy; Charité-Universitätsmedizin Berlin; Berlin; Germany
| | - C. Rosenberger
- Department of Nephrology; Charité-Universitätsmedizin Berlin; Berlin; Germany
| | - R. Mrowka
- Experimentelle Nephrologie; KIM III; Universitästsklinikum Jena; Jena; Germany
| | - S. Bachmann
- Department of Anatomy; Charité-Universitätsmedizin Berlin; Berlin; Germany
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Oliveira FST, Vieira-Filho LD, Cabral EV, Sampaio LS, Silva PA, Carvalho VCO, Vieyra A, Einicker-Lamas M, Lima VLM, Paixão ADO. Reduced cholesterol levels in renal membranes of undernourished rats may account for urinary Na+ loss. Eur J Nutr 2012; 52:1233-42. [DOI: 10.1007/s00394-012-0434-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2012] [Accepted: 07/30/2012] [Indexed: 01/11/2023]
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Wani NA, Kaur J. Reduced levels of folate transporters (PCFT and RFC) in membrane lipid rafts result in colonic folate malabsorption in chronic alcoholism. J Cell Physiol 2011; 226:579-87. [PMID: 21069807 DOI: 10.1002/jcp.22525] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
We studied the effect of chronic ethanol ingestion on folate transport across the colonic apical membranes (CAM) in rats. Male Wistar rats were fed 1 g/kg body weight/day ethanol (20%) solution orally for 3 months and folate transport was studied in the isolated colon apical membrane vesicles. The folate transport was found to be carrier mediated, saturable, with pH optima at 5.0. Chronic ethanol ingestion reduced the folate transport across the CAM by decreasing the affinity of transporters (high Km) for the substrate and by decreasing the number of transporter molecules (low Vmax) on the colon luminal surface. The decreased transport activity at the CAM was associated with down-regulation of the proton-coupled folate transporter (PCFT) and the reduced folate carrier (RFC) which resulted in decreased PCFT and RFC protein levels in the colon of rats fed alcohol chronically. Moreover, the PCFT and the RFC were found to be distributed in detergent insoluble fraction of the CAM in rats. Floatation experiments on Optiprep density gradients demonstrated the association of the PCFT and the RFC protein with lipid rafts (LR). Chronic alcoholism decreased the PCFT and the RFC protein levels in the CAM LR in accordance with the decreased synthesis. Hence, we propose that downregulation in the expression of the PCFT and the RFC in colon results in reduced levels of these transporters in colon apical membrane LR as a mechanism of folate malabsorption during chronic alcoholism.
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Affiliation(s)
- Nissar Ahmad Wani
- Department of Biochemistry, Postgraduate Institute of Medical Education and Research, Chandigarh, India
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24
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Lipid bilayer composition affects transmembrane protein orientation and function. J Lipids 2011; 2011:208457. [PMID: 21490797 PMCID: PMC3068514 DOI: 10.1155/2011/208457] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2010] [Accepted: 12/21/2010] [Indexed: 11/20/2022] Open
Abstract
Sperm membranes change in structure and composition upon ejaculation to undergo capacitation, a molecular transformation which enables spermatozoa to undergo the acrosome reaction and be capable of fertilization. Changes to the membrane environment including lipid composition, specifically lipid microdomains, may be responsible for enabling capacitation. To study the effect of lipid environment on proteins, liposomes were created using lipids extracted from bull sperm membranes, with or without a protein (Na+ K+-ATPase or α-amylase). Protein incorporation, function, and orientation were determined. Fluorescence resonance energy transfer (FRET) confirmed protein inclusion in the lipid bilayer, and protein function was confirmed using a colourometric assay of phosphate production from ATP cleavage. In the native lipid liposomes, ATPase was oriented with the β subunit facing the outer leaflet, while changing the lipid composition to 50% native lipids and 50% exogenous lipids significantly altered this orientation of Na+ K+-ATPase within the membranes.
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Steensgaard M, Svenningsen P, Tinning AR, Nielsen TD, Jørgensen F, Kjaersgaard G, Madsen K, Jensen BL. Apical serine protease activity is necessary for assembly of a high-resistance renal collecting duct epithelium. Acta Physiol (Oxf) 2010; 200:347-59. [PMID: 20645929 DOI: 10.1111/j.1748-1716.2010.02170.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
AIM We hypothesized that the serine protease prostasin is necessary for differentiation of a high-resistance renal collecting duct epithelium governed by glucocorticoid. METHODS Postnatal rat kidney and adult human kidney was used to study the expression and localization of prostasin. The murine collecting duct cell line (M-1) was cultured in Snapwell inserts to investigate the significance of prostasin for the development of transepithelial electrical resistance (TER). RESULTS In the cortex and medulla of rat kidney, prostasin mRNA and protein increased significantly between birth and weaning (day 21) and was detected in collecting ducts. Immunoreactive prostasin was associated with collecting ducts and loops of Henle in human kidney. In rat, adrenalectomy at day 10 had no effect on prostasin mRNA level in kidney at day 20. Cultured M-1 cells exhibited parallel increases in prostasin mRNA, protein and TER 5 days after seeding. Apical addition of the serine protease inhibitor aprotinin to M-1 cell cultures inhibited development of TER and led to aberrant localization of E-cadherin. This effect was mimicked by the protease inhibitor nafamostat. Apical addition of phospholipase C to cleave glycosylphosphatidylinositol (GPI) anchors released prostasin to the medium and attenuated development of TER with time of culture. Disruption of lipid rafts by methyl-β-cyclodextrin attenuated development of TER in M-1 cells. Omission of dexamethasone impaired development of TER in M-1 cells, while prostasin protein abundance and E-cadherin distribution did not change. CONCLUSION Apical, GPI-anchored, lipid raft-associated serine protease activity, compatible with prostasin, is necessary for the development of a high-resistance collecting duct epithelium.
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Affiliation(s)
- M Steensgaard
- Department of Cardiovascular and Renal Research, Institute of Molecular Medicine, University of Southern Denmark, Odense C, Denmark
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Shear stress promotes nitric oxide production in endothelial cells by sub-cellular delocalization of eNOS: A basis for shear stress mediated angiogenesis. Nitric Oxide 2010; 22:304-15. [PMID: 20188204 DOI: 10.1016/j.niox.2010.02.004] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2009] [Revised: 01/25/2010] [Accepted: 02/16/2010] [Indexed: 11/23/2022]
Abstract
This study aims to investigate the role of shear stress in cellular remodeling and angiogenesis with relation to nitric oxide (NO). We observed a 2-fold increase in endothelial cell (EC) migration in relation to actin re-arrangements under 15 dyne/cm(2) shear stress. Blocking NO production inhibited the migration and ring formation of ECs by 6-fold and 5-fold, respectively under shear stress. eNOS-siRNA knockdown technique also ascertained a 3-fold reduction in shear stress mediated ring formation. In ovo artery ligation model with a half and complete flow block for 30 min showed a reduction of angiogenesis by 50% and 70%, respectively. External stimulation with NO donor showed a 2-fold recovery in angiogenesis under both half and complete flow block conditions. NO intensity clustering studies by using Diaminofluorescein diacetate (DAF-2DA) probed endothelial monolayer depicted pattern-changes in NO distribution and cluster formation of ECs under shear stress. Immunofluorescence and live cell studies revealed an altered sub-cellular localization pattern of eNOS and phospho-eNOS under shear stress. In conclusion, shear-induced angiogenesis is mediated by nitric oxide dependent EC migration.
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Neurochemical changes on oxidative stress in rat hippocampus during acute phase of pilocarpine-induced seizures. Pharmacol Biochem Behav 2010; 94:341-5. [DOI: 10.1016/j.pbb.2009.09.015] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/16/2009] [Revised: 09/13/2009] [Accepted: 09/21/2009] [Indexed: 11/19/2022]
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Majumder S, Gupta R, Reddy H, Sinha S, Muley A, Kolluru GK, Chatterjee S. Cadmium attenuates bradykinin-driven nitric oxide production by interplaying with the localization pattern of endothelial nitric oxide synthase. Biochem Cell Biol 2009; 87:605-20. [PMID: 19767824 DOI: 10.1139/o09-018] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Cadmium, a ubiquitous heavy metal, interferes with endothelial functions and angiogenesis. Bradykinin is a Ca-mobilizing soluble peptide that acts via nitric oxide to promote vasodilation and capillary permeability. The objective of the present study was to explore the Cd implications in bradykinin-dependent endothelial functions. An egg yolk angiogenesis model was employed to evaluate the effect of Cd on bradykinin-induced angiogenesis. The results demonstrate that 100 nmol/L Cd attenuated bradykinin-dependent angiogenesis. The results of the in vitro wound healing and tube formation assays by using EAhy 926, a transformed endothelial cell line, suggest that Cd blocked bradykinin-mediated endothelial migration and tube formation by 38% and 67%, respectively, while nitric oxide supplementation could reverse the effect of Cd on bradykinin-induced endothelial migration by 94%. The detection of nitric oxide by using a DAF-2DA fluorescent probe, Griess assay, and ultrasensitive electrode suggests that Cd blocked bradykinin-induced nitric oxide production. Fluorescence imaging of eNOS-GFP transfected endothelial cells, immunofluorescence, and Western blot studies of Cd and bradykinin-treated cells show that Cd interfered with the localization pattern of eNOS, which possibly attenuates nitric oxide production in part. Additionally, Ca imaging of Cd- and bradykinin-treated cells suggests that Cd blocked bradykinin-dependent Ca influx into the cells, thus partially blocking Ca-dependent nitric oxide production in endothelial cells. The results of this study conclude that Cd blunted the effect of bradykinin by interfering with the Ca-associated NOS activity specifically by impeding subcellular trafficking of eNOS.
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Affiliation(s)
- Syamantak Majumder
- Vascular Biology Lab, Life Sciences Division, AU-KBC Research Centre, MIT Campus, Anna University, Chennai 600044, Tamil Nadu, India
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Wang X, Armando I, Upadhyay K, Pascua A, Jose PA. The regulation of proximal tubular salt transport in hypertension: an update. Curr Opin Nephrol Hypertens 2009; 18:412-420. [PMID: 19654544 PMCID: PMC3722593 DOI: 10.1097/mnh.0b013e32832f5775] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
PURPOSE OF REVIEW Renal proximal tubular sodium reabsorption is regulated by sodium transporters, including the sodium glucose transporter, sodium amino acid transporter, sodium hydrogen exchanger isoform 3 and sodium phosphate cotransporter type 2 located at the luminal/apical membrane, and sodium bicarbonate cotransporter and Na+/K+ATPase located at the basolateral membrane. This review summarizes recent studies on sodium transporters that play a major role in the increase in blood pressure in essential/polygenic hypertension. RECENT FINDINGS Sodium transporters and Na+/K+ATPase are segregated in membrane lipid and nonlipid raft microdomains that regulate their activities and trafficking via cytoskeletal proteins. The increase in renal proximal tubule ion transport in polygenic hypertension is primarily due to increased activity of NHE3 and Cl/HCO3 exchanger at the luminal/apical membrane and a primary or secondary increase in Na+/K+ATPase activity. SUMMARY The increase in renal proximal tubule ion transport in hypertension is due to increased actions by prohypertensive factors that are unopposed by antihypertensive factors.
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Affiliation(s)
- Xiaoyan Wang
- Center for Molecular Physiology Research, Children's Research Institute, Children's National Medical Center, Washington, District of Columbia, USA
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30
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Abstract
Glomerulonephritis is characterized by hematuria, proteinuria, hypertension, and edema, but the mechanisms contributing to volume disorders are controversial. Here we used the rat anti-Thy1 model of mesangioproliferative glomerulonephritis to test the hypothesis that disturbed salt and water homeostasis is based on tubular epithelial changes that cause salt retention. In this model there was an early onset of pronounced proteinuria and lipiduria associated with reduced fractional sodium excretion and a lowering of the renin-angiotensin-aldosterone system. The glomerular filtration rate and creatinine clearance were decreased on day 6. There was a reduced abundance of the major salt and water transport proteins on the proximal tubular brush border membrane and which paralleled cellular protein overload, enhanced membrane cholesterol uptake and cytoskeletal changes. Alterations in thick ascending limb were moderate. Changes in the collecting ducts were characterized by an enhanced abundance and increased subunit cleavage of the epithelial sodium channel, both events consistent with increased sodium reabsorption. We suggest that irrespective of the proximal tubular changes, altered collecting duct sodium reabsorption may be crucial for volume retention in acute glomerulonephritis. We suggest that enhanced proteolytic cleavage of ion transporter subunits might be a novel mechanism of channel activation in glomerular diseases. Whether these proteases are filtered or locally secreted awaits determination.
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Kastner C, Pohl M, Sendeski M, Stange G, Wagner CA, Jensen B, Patzak A, Bachmann S, Theilig F. Effects of receptor-mediated endocytosis and tubular protein composition on volume retention in experimental glomerulonephritis. Am J Physiol Renal Physiol 2009; 296:F902-11. [PMID: 19193726 DOI: 10.1152/ajprenal.90451.2008] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Human glomerulonephritis (GN) is characterized by sustained proteinuria, sodium retention, hypertension, and edema formation. Increasing quantities of filtered protein enter the renal tubule, where they may alter epithelial transport functions. Exaggerated endocytosis and consequent protein overload may affect proximal tubules, but intrinsic malfunction of distal epithelia has also been reported. A straightforward assignment to a particular tubule segment causing salt retention in GN is still controversial. We hypothesized that 1) trafficking and surface expression of major transporters and channels involved in volume regulation were altered in GN, and 2) proximal tubular endocytosis may influence locally as well as downstream expressed tubular transporters and channels. Effects of anti-glomerular basement membrane GN were studied in controls and megalin-deficient mice with blunted proximal endocytosis. Mice displayed salt retention and elevated systolic blood pressure when proteinuria had reached 10-15 mg/24 h. Surface expression of proximal Na(+)-coupled transporters and water channels was in part [Na(+)-P(i) cotransporter IIa (NaPi-IIa) and aquaporin-1 (AQP1)] increased by megalin deficiency alone, but unchanged (Na(+)/H(+) exchanger 3) or reduced (NaPi-IIa and AQP1) in GN irrespective of the endocytosis defect. In distal epithelia, significant increases in proteolytic cleavage products of alpha-epithelial Na(+) channel (ENaC) and gamma-ENaC were observed, suggesting enhanced tubular sodium reabsorption. The effects of glomerular proteinuria dominated over those of blunted proximal endocytosis in contributing to ENaC cleavage. Our data indicate that ENaC-mediated sodium entry may be the rate-limiting step in proteinuric sodium retention. Enhanced proteolytic cleavage of ENaC points to a novel mechanism of channel activation which may involve the action of filtered plasma proteases.
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Affiliation(s)
- Christian Kastner
- Charité-Universitätsmedizin Berlin, Institut für Vegetative Anatomie, Philippstr. 12, 10115 Berlin, Germany
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32
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Welker P, Böhlick A, Mutig K, Salanova M, Kahl T, Schlüter H, Blottner D, Ponce-Coria J, Gamba G, Bachmann S. Renal Na+-K+-Cl- cotransporter activity and vasopressin-induced trafficking are lipid raft-dependent. Am J Physiol Renal Physiol 2008; 295:F789-802. [PMID: 18579701 PMCID: PMC2536870 DOI: 10.1152/ajprenal.90227.2008] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2008] [Accepted: 06/17/2008] [Indexed: 11/22/2022] Open
Abstract
Apical bumetanide-sensitive Na(+)-K(+)-2Cl(-) cotransporter (NKCC2), the kidney-specific member of a cation-chloride cotransporter superfamily, is an integral membrane protein responsible for the transepithelial reabsorption of NaCl. The role of NKCC2 is essential for renal volume regulation. Vasopressin (AVP) controls NKCC2 surface expression in cells of the thick ascending limb of the loop of Henle (TAL). We found that 40-70% of Triton X-100-insoluble NKCC2 was present in cholesterol-enriched lipid rafts (LR) in rat kidney and cultured TAL cells. The related Na(+)-Cl(-) cotransporter (NCC) from rat kidney was distributed in LR as well. NKCC2-containing LR were detected both intracellularly and in the plasma membrane. Bumetanide-sensitive transport of NKCC2 as analyzed by (86)Rb(+) influx in Xenopus laevis oocytes was markedly reduced by methyl-beta-cyclodextrin (MbetaCD)-induced cholesterol depletion. In TAL, short-term AVP application induced apical vesicular trafficking along with a shift of NKCC2 from non-raft to LR fractions. In parallel, increased colocalization of NKCC2 with the LR ganglioside GM1 and their polar translocation were assessed by confocal analysis. Apical biotinylation showed twofold increases in NKCC2 surface expression. These effects were blunted by mevalonate-lovastatin/MbetaCD-induced cholesterol deprivation. Collectively, these findings demonstrate that a pool of NKCC2 distributes in rafts. Results are consistent with a model in which LR mediate polar insertion, activity, and AVP-induced trafficking of NKCC2 in the control of transepithelial NaCl transport.
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Affiliation(s)
- Pia Welker
- Institute of Anatomy, Charité-Universitätsmedizin Berlin, Philippstrasse 12, Berlin, Germany
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Welker P, Böhlick A, Mutig K, Salanova M, Kahl T, Schlüter H, Blottner D, Ponce-Coria J, Gamba G, Bachmann S. Renal Na+-K+-Cl- cotransporter activity and vasopressin-induced trafficking are lipid raft-dependent. Am J Physiol Renal Physiol 2008. [PMID: 18579701 DOI: 10.1152/ajprenal.90227] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Apical bumetanide-sensitive Na(+)-K(+)-2Cl(-) cotransporter (NKCC2), the kidney-specific member of a cation-chloride cotransporter superfamily, is an integral membrane protein responsible for the transepithelial reabsorption of NaCl. The role of NKCC2 is essential for renal volume regulation. Vasopressin (AVP) controls NKCC2 surface expression in cells of the thick ascending limb of the loop of Henle (TAL). We found that 40-70% of Triton X-100-insoluble NKCC2 was present in cholesterol-enriched lipid rafts (LR) in rat kidney and cultured TAL cells. The related Na(+)-Cl(-) cotransporter (NCC) from rat kidney was distributed in LR as well. NKCC2-containing LR were detected both intracellularly and in the plasma membrane. Bumetanide-sensitive transport of NKCC2 as analyzed by (86)Rb(+) influx in Xenopus laevis oocytes was markedly reduced by methyl-beta-cyclodextrin (MbetaCD)-induced cholesterol depletion. In TAL, short-term AVP application induced apical vesicular trafficking along with a shift of NKCC2 from non-raft to LR fractions. In parallel, increased colocalization of NKCC2 with the LR ganglioside GM1 and their polar translocation were assessed by confocal analysis. Apical biotinylation showed twofold increases in NKCC2 surface expression. These effects were blunted by mevalonate-lovastatin/MbetaCD-induced cholesterol deprivation. Collectively, these findings demonstrate that a pool of NKCC2 distributes in rafts. Results are consistent with a model in which LR mediate polar insertion, activity, and AVP-induced trafficking of NKCC2 in the control of transepithelial NaCl transport.
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Affiliation(s)
- Pia Welker
- Institute of Anatomy, Charité-Universitätsmedizin Berlin, Philippstrasse 12, Berlin, Germany
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Abstract
Biological rafts were identified and isolated at 37 degrees C and neutral pH. The strategy for isolating rafts utilized membrane tension to generate large domains. For lipid compositions that led only to microscropically unresolvable rafts in lipid bilayers, membrane tension led to the appearance of large, observable rafts. The large rafts converted back to small ones when tension was relieved. Thus, tension reversibly controls raft enlargement. For cells, application of membrane tension resulted in several types of large domains; one class of the domains was identified as rafts. Tension was generated in several ways, and all yielded raft fractions that had essentially the same composition, validating the principle of tension as a means to merge small rafts into large rafts. It was demonstrated that sphingomyelin-rich vesicles do not rise during centrifugation in sucrose gradients because they resist lysis, necessitating that, contrary to current experimental practice, membrane material be placed toward the top of a gradient for raft fractionation. Isolated raft fractions were enriched in a GPI-linked protein, alkaline phosphatase, and were poor in Na(+)-K(+) ATPase. Sphingomyelin and gangliosides were concentrated in rafts, the expected lipid raft composition. Cholesterol, however, was distributed equally between raft and nonraft fractions, contrary to the conventional view.
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Stefanello FM, Kreutz F, Scherer EBS, Breier AC, Vianna LP, Trindade VMT, Wyse ATS. Reduction of gangliosides, phospholipids and cholesterol content in cerebral cortex of rats caused by chronic hypermethioninemia. Int J Dev Neurosci 2007; 25:473-7. [PMID: 17890041 DOI: 10.1016/j.ijdevneu.2007.08.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2007] [Revised: 08/10/2007] [Accepted: 08/14/2007] [Indexed: 10/22/2022] Open
Abstract
Neurological dysfunction is observed in patients with severe hypermethioninemia, whose physiopathology is still poorly understood. In the current study we investigated the effect of chronic administration of methionine on the content and species of gangliosides and phospholipids, as well as on the concentration of cholesterol in rat cerebral cortex. Wistar rats received subcutaneous injections of methionine (1.34-2.68 micromol/g of body weight), twice a day, from the 6th to the 28th day of age and controls received saline. Animals were killed 12h after the last injection. Results showed that methionine administration significantly decreased the total content of lipids in cerebral cortex of rats. We also observed that this amino acid significantly reduced the absolute quantity of the major brain gangliosides (GM1, GD1a, GD1b and GT1b) and phospholipids (sphingomyelin, phosphatidylcholine and phosphatidylethanolamine). We also showed that Na+,K+-ATPase activity and TBARS were changed in cerebral cortex of rats subjected to hypermethioninemia. If confirmed in human beings, these data could suggest that the alteration in lipid composition, Na+,K+-ATPase activity and TBARS caused by methionine might contribute to the neurophysiopathology observed in hypermethioninemic patients.
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Affiliation(s)
- Francieli M Stefanello
- Departamento de Bioquímica, ICBS, Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcelos, 2600-Anexo, CEP 90035-003, Porto Alegre, RS, Brazil
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36
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Mutig K, Paliege A, Kahl T, Jöns T, Müller-Esterl W, Bachmann S. Vasopressin V2 receptor expression along rat, mouse, and human renal epithelia with focus on TAL. Am J Physiol Renal Physiol 2007; 293:F1166-77. [PMID: 17626156 DOI: 10.1152/ajprenal.00196.2007] [Citation(s) in RCA: 118] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
In renal epithelia, vasopressin influences salt and water transport, chiefly via vasopressin V(2) receptors (V(2)Rs) linked to adenylyl cyclase. A combination of vasopressin-induced effects along several distinct portions of the nephron and collecting duct system may help balance the net effects of antidiuresis in cortex and medulla. Previous studies of the intrarenal distribution of V(2)Rs have been inconclusive with respect to segment- and cell-type-related V(2)R expression. Our study therefore aimed to present a high-resolution analysis of V(2)R mRNA expression in rat, mouse, and human kidney epithelia, supplemented with immunohistochemical data. Cell types of the renal tubule were identified histochemically using specific markers. Pronounced V(2)R signal in thick ascending limb (TAL) was corroborated functionally; phosphorylation of Na(+)-K(+)-2Cl(-) cotransporter type 2 (NKCC2) was established in cultured TAL cells from rabbit and in rats with diabetes insipidus that were treated with the V(2)R agonist desmopressin. We found solid expression of V(2)R mRNA in medullary TAL (MTAL), macula densa, connecting tubule, and cortical and medullary collecting duct and weaker expression in cortical TAL and distal convoluted tubule in all three species. Additional V(2)R immunostaining of kidneys and rabbit TAL cells confirmed our findings. In agreement with strong V(2)R expression in MTAL, kidneys from rats with diabetes insipidus and cultured TAL cells revealed sharp, selective increases in NKCC2 phosphorylation upon desmopressin treatment. Macula densa cells constitutively showed strong NKCC2 phosphorylation. Results suggest comparably significant effects of vasopressin-induced V(2)R signaling in MTAL and in connecting tubule/collecting duct principal cells across the three species. Strong V(2)R expression in macula densa may be related to tubulovascular signal transfer.
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Affiliation(s)
- K Mutig
- Department of Anatomy, Charité Universitätsmedizin, Berlin, Germany
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