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Gillard BT, Amor N, Iraizoz FA, Pauža AG, Campbell C, Greenwood MP, Alagaili AN, Murphy D. Mobilisation of jerboa kidney gene networks during dehydration and opportunistic rehydration. iScience 2023; 26:107574. [PMID: 37664605 PMCID: PMC10470305 DOI: 10.1016/j.isci.2023.107574] [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: 05/10/2023] [Revised: 06/30/2023] [Accepted: 08/04/2023] [Indexed: 09/05/2023] Open
Abstract
Desert animals have evolved systems that enable them to thrive under dry conditions. Focusing on the kidney, we have investigated the transcriptomic adaptations that enable a desert rodent, the Lesser Egyptian Jerboa (Jaculus jaculus), to withstand water deprivation and opportunistic rehydration. Analysis of the whole kidney transcriptome showed many differentially expressed genes in the Jerboa kidney, 6.4% of genes following dehydration and an even greater number (36.2%) following rehydration compared to control. Genes correlated with the rehydration condition included many ribosomal protein coding genes suggesting a concerted effort to accelerate protein synthesis when water is made available. We identify an increase in TGF-beta signaling antagonists in dehydration (e.g., GREM2). We also describe expression of multiple aquaporin and solute carrier transporters mapped to specific nephron segments. The desert adapted renal transcriptome presented here is a valuable resource to expand our understanding of osmoregulation beyond that derived from model organisms.
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Affiliation(s)
- Benjamin T. Gillard
- Molecular Neuroendocrinology Research Group, Bristol Medical School: Translational Health Sciences, Dorothy Hodgkin Building, University of Bristol, Bristol, England
| | - Nabil Amor
- LR18ES05, Laboratory of Biodiversity, Parasitology and Ecology of Aquatic Ecosystems, Department of Biology - Faculty of Sciences of Tunis, University of Tunis El Manar, Tunisia
| | - Fernando Alvira Iraizoz
- Molecular Neuroendocrinology Research Group, Bristol Medical School: Translational Health Sciences, Dorothy Hodgkin Building, University of Bristol, Bristol, England
| | - Audrys G. Pauža
- Molecular Neuroendocrinology Research Group, Bristol Medical School: Translational Health Sciences, Dorothy Hodgkin Building, University of Bristol, Bristol, England
| | - Colin Campbell
- Department of Engineering Mathematics, Ada Lovelace Building, University of Bristol, Bristol, England
| | - Michael P. Greenwood
- Molecular Neuroendocrinology Research Group, Bristol Medical School: Translational Health Sciences, Dorothy Hodgkin Building, University of Bristol, Bristol, England
| | | | - David Murphy
- Molecular Neuroendocrinology Research Group, Bristol Medical School: Translational Health Sciences, Dorothy Hodgkin Building, University of Bristol, Bristol, England
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2
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Zhang Y, Huang H, Kong Y, Xu C, Dai L, Geng X, Deng Y, Wang Y, Liu Y, Meng C, Zhang X, Li J, Qin J, Feng B, Mak KK, Wang L, Huang Y, Wang W, Lan HY, Yang B, Lu HAJ, Xia Y. Kidney tubular transcription co-activator, Yes-associated protein 1 (YAP), controls the expression of collecting duct aquaporins and water homeostasis. Kidney Int 2023; 103:501-513. [PMID: 36328098 DOI: 10.1016/j.kint.2022.10.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Revised: 09/14/2022] [Accepted: 10/18/2022] [Indexed: 11/16/2022]
Abstract
Final urine volume and concentration are defined by water reabsorption through the water channel proteins aquaporin (AQP)-2, -3 and -4 in the collecting duct. However, the transcriptional regulation of these AQPs is not well understood. The Hippo/Yes-associated protein 1 (YAP) pathway plays an important role in organ size control and tissue homeostasis. When the Hippo pathway including the Mst1/Mst2 kinases is inhibited, YAP is activated and functions as a transcription co-activator. Our previous work revealed a pathological role of tubular YAP activation in chronic kidney disease, but the physiological role of YAP in the kidney remains to be established. Here, we found that tubule-specific Yap knockout mice showed increased urine output and decreased urinary osmolality. Decreases in Aqp2, -3 and -4 mRNA and protein abundance in the kidney were evident in Yap knockout mice. Analysis of Mst1/Mst2 double knockout and Mst1/Mst2/Yap triple knockout mice showed that expression of Aqp2 and Aqp4 but not Aqp3 was dependent on YAP. Furthermore, YAP was recruited to the promoters of the Aqp2 and Aqp4 genes and stimulated their transcription. Interestingly, YAP was found to interact with transcription factors GATA2, GATA3 and NFATc1. These three factors promoted Aqp2 transcription in a YAP dependent manner in collecting duct cells. These three factors also promoted Aqp4 transcription whereas only GATA2 and GATA3 enhanced Aqp3 transcription. Thus, our results suggest that YAP promotes Aqp2 and Aqp4 transcription, interacts with GATA2, GATA3 and NFATc1 to control Aqp2 expression, while Aqp-2, -3 and -4 exploit overlapping mechanisms for their baseline transcriptional regulation.
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Affiliation(s)
- Yu Zhang
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, China
| | - Huihui Huang
- Division of Nephrology, Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts
| | - Yonglun Kong
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, China
| | - Chunhua Xu
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, China
| | - Liujiang Dai
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, China
| | - Xiaoqiang Geng
- Department of Pharmacology, School of Basic Medical Sciences, Peking University, Beijing, China
| | | | - Yang Wang
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, China
| | - Yang Liu
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, China; Department of Nephrology, Center of Nephrology and Urology, The Seventh Affiliated Hospital, Sun Yat-sen University, Shenzhen, China
| | - Chenling Meng
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, China
| | - Xiaoyi Zhang
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, China
| | - Jinhong Li
- Department of Nephrology, Center of Nephrology and Urology, The Seventh Affiliated Hospital, Sun Yat-sen University, Shenzhen, China
| | - Jinzhong Qin
- The Key Laboratory of Model Animal for Disease Study of Ministry of Education, Model Animal Research Center, Nanjing University, Nanjing, China
| | - Bo Feng
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, China
| | - Kingston Kinglun Mak
- Department of Biomedical Sciences, City University of Hong Kong, Hong Kong, China
| | - Li Wang
- Department of Biomedical Sciences, City University of Hong Kong, Hong Kong, China
| | - Yu Huang
- Department of Biomedical Sciences, City University of Hong Kong, Hong Kong, China
| | - Weidong Wang
- Department of Pathophysiology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China
| | - Hui-Yao Lan
- Department of Medicine and Therapeutics, Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Hong Kong, China; Guangdong-Hong Kong Joint Laboratory for Immune and Genetic Kidney Disease, Guangdong Provincial People's Hospital and Guangdong Academy of Medical Sciences, Guangzhou, and The Chinese University of Hong Kong, Hong Kong, China
| | - Baoxue Yang
- Department of Pharmacology, School of Basic Medical Sciences, Peking University, Beijing, China
| | - Hua A Jenny Lu
- Division of Nephrology, Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts
| | - Yin Xia
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, China; Guangdong-Hong Kong Joint Laboratory for Immune and Genetic Kidney Disease, Guangdong Provincial People's Hospital and Guangdong Academy of Medical Sciences, Guangzhou, and The Chinese University of Hong Kong, Hong Kong, China; Key Laboratory for Regenerative Medicine, Ministry of Education, School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, China.
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3
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Pisani F, Simone L, Mola MG, De Bellis M, Frigeri A, Nicchia GP, Svelto M. Regulation of aquaporin-4 expression in the central nervous system investigated using M23-AQP4 null mouse. Glia 2021; 69:2235-2251. [PMID: 34038017 PMCID: PMC8361696 DOI: 10.1002/glia.24032] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Revised: 04/15/2021] [Accepted: 05/17/2021] [Indexed: 12/22/2022]
Abstract
In astrocytes, unknown mechanisms regulate the expression of M1 and M23 isoforms of water channel aquaporin-4 (M1-AQP4 and M23-AQP4). The ratio between these two isoforms controls the AQP4 assembly state in the plasma membrane known as orthogonal arrays of particles (OAPs). To give new insights into these mechanisms, here, we explore the regulation of AQP4 expression in the spinal cord of a CRISPR/Cas9 M23-null mouse model (M23-null). In the M23-null spinal cord OAP assembly, the perivascular localization of AQP4 and M1-AQP4 protein were drastically reduced. In heterozygous, M1-AQP4 was proportionally reduced with M23-AQP4, maintaining the isoform ratio unaffected. We hypothesize a role of the M23-AQP4 in the regulation of M1-AQP4 expression. M1-AQP4 transcription, splicing and M1-AQP4 protein degradation were found to be unaffected in M23-null spinal cord and in M23-null astrocyte primary culture. The translational control was investigated by mRNA-protein pull down and quantitative mass spectrometry, to isolate and quantify AQP4 mRNA binding proteins (AQP4-RBPs). Compared to WT, in M23-null spinal cord, the interaction between AQP4 mRNA and polypyrimidine tract binding protein 1, a positive regulator of AQP4 translation, was higher, while interaction with the RNA helicase DDX17 was lower. In astrocyte primary cultures, DDX17 knockdown upregulated AQP4 protein expression and increased cell swelling, leaving AQP4 mRNA levels unchanged. Here, we identify AQP4-RBPs and provide evidence that in mouse spinal cord M23-AQP4 deletion changes the interaction between AQP4 mRNA and some RBPs involved in AQP4 translation. We describe for the first time the RNA helicase DDX17 as a regulator of AQP4 expression in astrocytes.
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Affiliation(s)
- Francesco Pisani
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari Aldo Moro, Bari, Italy
| | - Laura Simone
- Fondazione IRCCS Casa Sollievo della Sofferenza, Cancer Stem Cells Unit, San Giovanni Rotondo (FG), Italy
| | - Maria Grazia Mola
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari Aldo Moro, Bari, Italy
| | - Manuela De Bellis
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari Aldo Moro, Bari, Italy
| | - Antonio Frigeri
- School of Medicine, Department of Basic Medical Sciences, Neuroscience and Sense Organs, University of Bari Aldo Moro, Bari, Italy
| | - Grazia Paola Nicchia
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari Aldo Moro, Bari, Italy
| | - Maria Svelto
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari Aldo Moro, Bari, Italy.,Institute of Biomembranes and Bioenergetics, National Research Council, Bari, Italy.,National Institute of Biostructures and Biosystems (INBB), Rome, Italy
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4
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Kim WO, Kim SA, Jung YA, Suh SI, Ryoo YW. Ultraviolet B Downregulated Aquaporin 1 Expression via the MEK/ERK pathway in the Dermal Fibroblasts. Ann Dermatol 2020; 32:213-222. [PMID: 33911740 PMCID: PMC7992625 DOI: 10.5021/ad.2020.32.3.213] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Revised: 12/04/2019] [Accepted: 01/21/2020] [Indexed: 11/20/2022] Open
Abstract
Background Aquaporin 1 (AQP1) is a transmembrane channel protein that allows rapid transposition of water and gases, in recent discoveries of AQP1 function involve cell proliferation, differentiation, wound healing, inflammation and infection in different cell types, suggesting that AQP1 plays key roles in diverse biologic process. Until now, less is known about the function of AQP1 on ultraviolet radiation induced photoaged skin. Objective In this study we set out to examine whether AQP1 expression may be influenced by repeated irradiation of ultraviolet B (UVB) in cultured dermal fibroblasts. Methods To elucidate the function of AQP1 in skin photoaging, human dermal fibroblasts (HS68) were irradiated by a series of 4 sub-cytotoxic doses of UVB which are known as UV-induced cell premature senescence model. Reverse transcription polymerase chain reaction and Western blotting were conducted to detect AQP1 expression from different groups. Then, cells were transfected with AQP1-targeting small interfering RNA. The activities of signaling proteins upon UVB irradiation were investigated to determine which pathways are involved in AQP1 expression. Results AQP1 expression was increased by 100 mJ/cm2 of UVB irradiation, but decreased by 200 mJ/cm2. Depletion of the AQP1 increased the apoptotic sensitivity of cells to UVB, as judged by upregulation of the p53, p21, poly (adenosine diphosphate [ADP]-ribose) polymerase and Bax together with the increased Bax/Bcl2 ratio. UVB induced downregulation of AQP1 was significantly attenuated by pretreatment with the MEK/ERK inhibitor (PD98059). Conclusion We concluded that AQP1 expression was down-regulated by repeated exposure of UVB via MEK/ERK activation pathways. The AQP1 reduction by UVB lead to changes of physiological functions in dermal fibroblasts, which might be associated with the occurrence and development of UVB induced photoaging.
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Affiliation(s)
- Won-Oh Kim
- Department of Dermatology, Institute for Medical Science, School of Medicine, Keimyung University, Daegu, Korea
| | - Sung-Ae Kim
- Department of Dermatology, Institute for Medical Science, School of Medicine, Keimyung University, Daegu, Korea
| | - Yun-A Jung
- Department of Dermatology, Institute for Medical Science, School of Medicine, Keimyung University, Daegu, Korea
| | - Sung-Il Suh
- Department of Microbiology, Institute for Medical Science, School of Medicine, Keimyung University, Daegu, Korea
| | - Young-Wook Ryoo
- Department of Dermatology, Institute for Medical Science, School of Medicine, Keimyung University, Daegu, Korea
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5
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Zhang J, Li S, Deng F, Baikeli B, Huang S, Wang B, Liu G. Higher Expression Levels of Aquaporin Family of Proteins in the Kidneys of Arid-Desert Living Lepus yarkandensis. Front Physiol 2019; 10:1172. [PMID: 31572217 PMCID: PMC6751383 DOI: 10.3389/fphys.2019.01172] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Accepted: 08/29/2019] [Indexed: 12/20/2022] Open
Abstract
Lepus yarkandensis specifically lives in arid climate with rare precipitation of Tarim Basin in western China. Aquaporins (AQPs) are a family of channel proteins that facilitate water transportation across cell membranes. Kidney AQPs play vital roles in renal tubule water permeability and maintenance of body water homeostasis. This study aimed to investigate whether kidney AQPs exhibit higher expression in arid-desert living animals. Immunohistochemistry results revealed localization of AQP1 to the capillary endothelial cells in glomerulus and epithelial cells in proximal tubule and descending thin limbs, AQP2 to the apical plasma membrane of principal cells in the cortical collecting duct (CCD), outer medullary collecting duct (OMCD), and IMCD cells in the initial inner medullary collecting duct (IMCD1) and middle IMCD (IMCD2), and AQP3 and AQP4 to the basolateral plasma membrane of principal cells and IMCD cells in CCD, OMCD, IMCD1, and IMCD2 in L. yarkandensis kidneys. Quantitative real-time PCR analysis showed higher mRNA levels of AQP1, AQP2, AQP3, and AQP4 in L. yarkandensis kidneys compared with Oryctolagus cuniculus. Similar results were obtained by western blotting. Our results suggested that higher expression levels of AQP1, AQP2, AQP3, and AQP4 in L. yarkandensis kidneys favored for drawing more water from the tubular fluid.
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Affiliation(s)
- Jianping Zhang
- College of Life Science, Tarim University, Alar, China.,Department of Basic Veterinary Medicine, College of Animal Science and Veterinary Medicine, Huazhong Agricultural University, Wuhan, China.,Key Laboratory of Protection and Utilization of Biological Resources in Tarim Basin, Tarim University, Alar, China
| | - Shuwei Li
- College of Life Science, Tarim University, Alar, China.,Key Laboratory of Protection and Utilization of Biological Resources in Tarim Basin, Tarim University, Alar, China
| | - Fang Deng
- College of Life Science, Tarim University, Alar, China
| | | | - Shuguang Huang
- Department of Basic Veterinary Medicine, College of Animal Science and Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
| | - Binyu Wang
- Department of Basic Veterinary Medicine, College of Animal Science and Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
| | - Guoquan Liu
- Department of Basic Veterinary Medicine, College of Animal Science and Veterinary Medicine, Huazhong Agricultural University, Wuhan, China.,Anhui Province Key Laboratory of Translational Cancer Research, Department of Biochemistry, College of Laboratory Medicine, Bengbu Medical College, Bengbu, China
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6
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Giorello FM, Feijoo M, D'Elía G, Naya DE, Valdez L, Opazo JC, Lessa EP. An association between differential expression and genetic divergence in the Patagonian olive mouse (Abrothrix olivacea). Mol Ecol 2018; 27:3274-3286. [PMID: 29940092 DOI: 10.1111/mec.14778] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Revised: 05/30/2018] [Accepted: 05/31/2018] [Indexed: 12/19/2022]
Abstract
Recent molecular studies have found striking differences between desert-adapted species and model mammals regarding water conservation. In particular, aquaporin 4, a classical gene involved in water regulation of model species, is absent or not expressed in the kidneys of desert-adapted species. To further understand the molecular response to water availability, we studied the Patagonian olive mouse Abrothrix olivacea, a species with an unusually broad ecological tolerance that exhibits a great urine concentration capability. The species is able to occupy both the arid Patagonian steppe and the Valdivian and Magellanic forests. We sampled 95 olive mouse specimens from four localities (two in the steppe and two in the forests) and analysed both phenotypic variables and transcriptomic data to investigate the response of this species to the contrasting environmental conditions. The relative size of the kidney and the ratio of urine to plasma concentrations were, as expected, negatively correlated with annual rainfall. Expression analyses uncovered nearly 3,000 genes that were differentially expressed between steppe and forest samples and indicated that this species resorts to the "classical" gene pathways for water regulation. Differential expression across biomes also involves genes that involved in immune and detoxification functions. Overall, genes that were differentially expressed showed a slight tendency to be more divergent and to display an excess of intermediate allele frequencies, relative to the remaining loci. Our results indicate that both differential expression in pathways involved in water conservation and geographical allelic variation are important in the occupation of contrasting habitats by the Patagonian olive mouse.
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Affiliation(s)
- Facundo M Giorello
- Departamento de Ecología y Evolución, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay
- Espacio de Biología Vegetal del Noreste, Centro Universitario de Tacuarembó, Universidad de la República, Tacuarembó, Uruguay
| | - Matias Feijoo
- Departamento de Ecología y Evolución, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay
| | - Guillermo D'Elía
- Instituto de Ciencias Ambientales y Evolutivas, Universidad Austral de Chile, Valdivia, Chile
| | - Daniel E Naya
- Departamento de Ecología y Evolución, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay
| | - Lourdes Valdez
- Instituto de Ciencias Ambientales y Evolutivas, Universidad Austral de Chile, Valdivia, Chile
| | - Juan C Opazo
- Instituto de Ciencias Ambientales y Evolutivas, Universidad Austral de Chile, Valdivia, Chile
| | - Enrique P Lessa
- Departamento de Ecología y Evolución, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay
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Elgot A, El Hiba O, Belkouch M, Gamrani H. The underlying physiological basis of the desert rodent Meriones shawi's survival to prolonged water deprivation: Central vasopressin regulation on peripheral kidney water channels AQPs-2. Acta Histochem 2018; 120:65-72. [PMID: 29217107 DOI: 10.1016/j.acthis.2017.11.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Revised: 11/15/2017] [Accepted: 11/17/2017] [Indexed: 12/19/2022]
Abstract
Meriones shawi (M. shawi) is a particular semi-desert rodent known by its resistance to long periods of thirst. The aim of the present investigation is to clarify the underlying mechanisms allowing M. shawi to resist to hard conditions of dehydration. For this reason we used two different approaches: i) a morphometric study, which consists in measuring the effect of dehydration on body and kidneys weights as well as the report kidney weight/body weight, ii) By immunohistochemistry, we proceed to study the effect of dehydration on the immunoreactivity of central vasopressin (AVP) and the kidney aquaporin-2 (AQP-2) which is a channel protein that allows water to permeate across cell membranes. Our results showed both a body mass decrease accompanied by a remarkable kidneys hypertrophy. The immunohistochemical study showed a significant increase of AQP-2 immunoreactivity in the medullar part of Meriones kidneys allowing probably to Meriones a great ability to water retention. Consistently, we demonstrate that the increased AQP-2 expression occurred together with an increase in vasopressin (AVP) expression in both hypothalamic supraoptic (SON) and paraventricular nucleus (PVN), which are a major hub in the osmotic control circuitry. These various changes seen either in body weight and kidneys or at the cellular level might be the basis of peripheral control of body water homeostasis, providing to M. shawia strong resistance against chronic dehydration.
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Influence of sex on aquaporin1-4 and vasopressin V2 receptor expression in the pig kidney during development. Pediatr Res 2016; 80:452-9. [PMID: 27089501 DOI: 10.1038/pr.2016.94] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Accepted: 03/15/2016] [Indexed: 11/09/2022]
Abstract
BACKGROUND The ability of the immature kidney to concentrate urine is lower than in adults. The aquaporin (AQP) family and the vasopressin V2 receptor (V2R) play a critical role in the urinary concentrating capacity. Here we investigated a possible sex difference in AQP1, AQP2, AQP3, and AQP4 as well as V2R expression in the fetal pig kidney at different gestation stages. METHODS Pig fetuses were divided into three groups according to gestation age of 60, 80, and 100 d. Quantitative PCR and immunohistochemistry were used to determine the regulation of AQP1, AQP2, AQP3, and AQP4 as well as V2R in the fetal pig kidneys. RESULTS Renal AQP1, AQP2 and AQP3, and V2R expression was increased with gestation age in both sexes, whereas AQP4 expression was unchanged over time. We observed neither sex differences in the AQPs nor V2R expression in the fetal pig kidneys. CONCLUSION AQP1, AQP2, and AQP3, and V2R expression increased with gestation age in the fetal kidney, suggesting that this induction might contribute to the maturation of urinary concentrating capacity. However, no sex differences were observed indicating that sex might not play a role for the maturation of the urinary concentrating activity during kidney development in fetal pig.
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9
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Galán-Cobo A, Ramírez-Lorca R, Echevarría M. Role of aquaporins in cell proliferation: What else beyond water permeability? Channels (Austin) 2016; 10:185-201. [PMID: 26752515 PMCID: PMC4954585 DOI: 10.1080/19336950.2016.1139250] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Revised: 12/30/2015] [Accepted: 12/31/2015] [Indexed: 02/07/2023] Open
Abstract
In addition to the extensive data demonstrating the importance of mammalian AQPs for the movement of water and some small solutes across the cell membrane, there is now a growing body of evidence indicating the involvement of these proteins in numerous cellular processes seemingly unrelated, at least some of them in a direct way, to their canonical function of water permeation. Here, we have presented a broad range of evidence demonstrating that these proteins have a role in cell proliferation by various different mechanisms, namely, by allowing fast cell volume regulation during cell division; by affecting progression of cell cycle and helping maintain the balance between proliferation and apoptosis, and by crosstalk with other cell membrane proteins or transcription factors that, in turn, modulate progression of the cell cycle or regulate biosynthesis pathways of cell structural components. In the end, however, after discussing all these data that strongly support a role for AQPs in the cell proliferation process, it remains impossible to conclude that all these other functions attributed to AQPs occur completely independently of their water permeability, and there is a need for new experiments designed specifically to address this interesting issue.
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Affiliation(s)
- Ana Galán-Cobo
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla (Departamento de Fisiología Médica y Biofísica), Seville, Spain
| | - Reposo Ramírez-Lorca
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla (Departamento de Fisiología Médica y Biofísica), Seville, Spain
| | - Miriam Echevarría
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla (Departamento de Fisiología Médica y Biofísica), Seville, Spain
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10
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Kortenoeven MLA, Pedersen NB, Rosenbaek LL, Fenton RA. Vasopressin regulation of sodium transport in the distal nephron and collecting duct. Am J Physiol Renal Physiol 2015; 309:F280-99. [DOI: 10.1152/ajprenal.00093.2015] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Accepted: 05/27/2015] [Indexed: 12/22/2022] Open
Abstract
Arginine vasopressin (AVP) is released from the posterior pituitary gland during states of hyperosmolality or hypovolemia. AVP is a peptide hormone, with antidiuretic and antinatriuretic properties. It allows the kidneys to increase body water retention predominantly by increasing the cell surface expression of aquaporin water channels in the collecting duct alongside increasing the osmotic driving forces for water reabsorption. The antinatriuretic effects of AVP are mediated by the regulation of sodium transport throughout the distal nephron, from the thick ascending limb through to the collecting duct, which in turn partially facilitates osmotic movement of water. In this review, we will discuss the regulatory role of AVP in sodium transport and summarize the effects of AVP on various molecular targets, including the sodium-potassium-chloride cotransporter NKCC2, the thiazide-sensitive sodium-chloride cotransporter NCC, and the epithelial sodium channel ENaC.
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Affiliation(s)
- M. L. A. Kortenoeven
- Department of Biomedicine and Center for Interactions of Proteins in Epithelial Transport (InterPrET), Aarhus University, Aarhus, Denmark
| | - N. B. Pedersen
- Department of Biology, Faculty of Science, University of Copenhagen, Copenhagen, Denmark; and
| | - L. L. Rosenbaek
- Department of Cellular and Molecular Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - R. A. Fenton
- Department of Biomedicine and Center for Interactions of Proteins in Epithelial Transport (InterPrET), Aarhus University, Aarhus, Denmark
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Marlar S, Arnspang EC, Koffman JS, Løcke EM, Christensen BM, Nejsum LN. Elevated cAMP increases aquaporin-3 plasma membrane diffusion. Am J Physiol Cell Physiol 2014; 306:C598-606. [PMID: 24452376 DOI: 10.1152/ajpcell.00132.2013] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Regulated urine concentration takes place in the renal collecting duct upon arginine vasopressin (AVP) stimulation, where subapical vesicles containing aquaporin-2 (AQP2) are inserted into the apical membrane instantly increasing water reabsorption and urine concentration. The reabsorped water exits via basolateral AQP3 and AQP4. Upon long-term stimulation with AVP or during thirst, expression levels of both AQP2 and AQP3 are increased; however, there is so far no evidence for short-term AVP regulation of AQP3 or AQP4. To facilitate the increase in transepithelial water transport, AQP3 may be short-term regulated via changes in protein-protein interactions, incorporation into lipid rafts, and/or changes in steady-state turnover, which could result in changes in the diffusion behavior of AQP3. Thus we measured AQP3 diffusion coefficients upon stimulation with the AVP mimic forskolin to reveal if AQP3 could be short-term regulated by AVP. k-Space image correlation spectroscopy (kICS) analysis of time-lapse image sequences of basolateral enhanced green fluorescent protein-tagged AQP3 (AQP3-EGFP) revealed that the forskolin-mediated elevation of cAMP increased the diffusion coefficient by 58% from 0.0147 ± 0.0082 μm(2)/s (control) to 0.0232 ± 0.0085 μm(2)/s (forskolin, P < 0.05). Quantum dot-conjugated antibody labeling also revealed a significant increase in AQP3 diffusion upon forskolin treatment by 44% [0.0104 ± 0.0040 μm(2)/s (control) vs. 0.0150 ± 0.0016 μm(2)/s (forskolin, P < 0.05)]. Immunoelectron microscopy showed no obvious difference in AQP3-EGFP expression levels or localization in the plasma membrane upon forskolin stimulation. Thus AQP3-EGFP diffusion is altered upon increased cAMP, which may correspond to basolateral adaptations in response to the increased apical water readsorption.
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Affiliation(s)
- Saw Marlar
- Institute of Molecular Biology and Genetics and Interdisciplinary Nanoscience Center, Aarhus University, Aarhus, Denmark; and
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12
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Kortenoeven MLA, Fenton RA. Renal aquaporins and water balance disorders. Biochim Biophys Acta Gen Subj 2013; 1840:1533-49. [PMID: 24342488 DOI: 10.1016/j.bbagen.2013.12.002] [Citation(s) in RCA: 100] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2013] [Revised: 11/26/2013] [Accepted: 12/09/2013] [Indexed: 12/17/2022]
Abstract
BACKGROUND Aquaporins (AQPs) are a family of proteins that can act as water channels. Regulation of AQPs is critical to osmoregulation and the maintenance of body water homeostasis. Eight AQPs are expressed in the kidney of which five have been shown to play a role in body water balance; AQP1, AQP2, AQP3, AQP4 and AQP7. AQP2 in particular is regulated by vasopressin. SCOPE OF REVIEW This review summarizes our current knowledge of the underlying mechanisms of various water balance disorders and their treatment strategies. MAJOR CONCLUSIONS Dysfunctions of AQPs are involved in disorders associated with disturbed water homeostasis. Hyponatremia with increased AQP levels can be caused by diseases with low effective circulating blood volume, such as congestive heart failure, or osmoregulation disorders such as the syndrome of inappropriate secretion of antidiuretic hormone. Treatment consists of fluid restriction, demeclocycline and vasopressin type-2 receptor antagonists. Decreased AQP levels can lead to diabetes insipidus (DI), characterized by polyuria and polydipsia. In central DI, vasopressin production is impaired, while in gestational DI, levels of the vasopressin-degrading enzyme vasopressinase are abnormally increased. Treatment consists of the vasopressin analogue dDAVP. Nephrogenic DI is caused by the inability of the kidney to respond to vasopressin and can be congenital, but is most commonly acquired, usually due to lithium therapy. Treatment consists of sufficient fluid supply, low-solute diet and diuretics. GENERAL SIGNIFICANCE In recent years, our understanding of the underlying mechanisms of water balance disorders has increased enormously, which has opened up several possible new treatment strategies. This article is part of a Special Issue entitled Aquaporins.
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Affiliation(s)
- Marleen L A Kortenoeven
- Department of Biomedicine, Aarhus University, Aarhus, Denmark; Center for Interactions of Proteins in Epithelial Transport (InterPrET), Aarhus University, Aarhus, Denmark.
| | - Robert A Fenton
- Department of Biomedicine, Aarhus University, Aarhus, Denmark; Center for Interactions of Proteins in Epithelial Transport (InterPrET), Aarhus University, Aarhus, Denmark.
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Cellular overexpression of Aquaporins slows down the natural HIF-2α degradation during prolonged hypoxia. Gene 2013; 522:18-26. [DOI: 10.1016/j.gene.2013.03.075] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2012] [Revised: 02/19/2013] [Accepted: 03/16/2013] [Indexed: 10/27/2022]
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Poulsen SB, Kim YH, Frøkiær J, Nielsen S, Christensen BM. Long-term vasopressin-V2-receptor stimulation induces regulation of aquaporin 4 protein in renal inner medulla and cortex of Brattleboro rats. Nephrol Dial Transplant 2013; 28:2058-65. [DOI: 10.1093/ndt/gft088] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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15
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Fenton RA, Praetorius J. Molecular Physiology of the Medullary Collecting Duct. Compr Physiol 2011; 1:1031-56. [DOI: 10.1002/cphy.c100064] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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16
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García-Miranda P, Peral MJ, Ilundain AA. Rat small intestine expresses the reelin-Disabled-1 signalling pathway. Exp Physiol 2010; 95:498-507. [DOI: 10.1113/expphysiol.2009.050682] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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17
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Peral M, Vázquez-Carretero M, Ilundain A. Na+/Cl−/creatine transporter activity and expression in rat brain synaptosomes. Neuroscience 2010; 165:53-60. [DOI: 10.1016/j.neuroscience.2009.10.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2009] [Revised: 10/01/2009] [Accepted: 10/01/2009] [Indexed: 10/20/2022]
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Tchapyjnikov D, Li Y, Pisitkun T, Hoffert JD, Yu MJ, Knepper MA. Proteomic profiling of nuclei from native renal inner medullary collecting duct cells using LC-MS/MS. Physiol Genomics 2009; 40:167-83. [PMID: 19996160 DOI: 10.1152/physiolgenomics.00148.2009] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Vasopressin is a peptide hormone that regulates renal water excretion in part through its actions on the collecting duct. The regulation occurs in part via control of transcription of genes coding for the water channels aquaporin-2 (Aqp2) and aquaporin-3 (Aqp3). To identify transcription factors expressed in collecting duct cells, we have carried out LC-MS/MS-based proteomic profiling of nuclei isolated from native rat inner medullary collecting ducts (IMCDs). To maximize the number of proteins identified, we matched spectra to rat amino acid sequences using three different search algorithms (SEQUEST, InsPecT, and OMSSA). All searches were coupled to target-decoy methodology to limit false-discovery identifications to 2% of the total for single-peptide identifications. In addition, we developed a computational tool (ProMatch) to identify and eliminate ambiguous identifications. With this approach, we identified >3,500 proteins, including 154 proteins classified as "transcription factor" proteins (Panther Classification System). Among these, are members of CREB, ETS, RXR, NFAT, HOX, GATA, EBOX, EGR, MYT1, KLF, and CP2 families, which were found to have evolutionarily conserved putative binding sites in the 5'-flanking region or first intron of the Aqp2 gene, as well as members of EBOX, NR2, GRE, MAZ, KLF, and SP1 families corresponding to conserved sites in the 5'-flanking region of the Aqp3 gene. In addition, several novel phosphorylation sites in nuclear proteins were identified using the neutral loss-scanning LC-MS(3) technique. The newly identified proteins have been incorporated into the IMCD Proteome Database (http://dir.nhlbi.nih.gov/papers/lkem/imcd/).
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Affiliation(s)
- Dmitry Tchapyjnikov
- Epithelial Systems Biology Laboratory, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland 20892-1603, USA
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Hasler U, Leroy V, Martin PY, Féraille E. Aquaporin-2 abundance in the renal collecting duct: new insights from cultured cell models. Am J Physiol Renal Physiol 2009; 297:F10-8. [DOI: 10.1152/ajprenal.00053.2009] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
The renal cortico-papillary osmotic gradient is generated by sodium reabsorption in the thick ascending limb. The antidiuretic hormone arginine vasopressin (AVP) increases collecting duct water permeability by enhancing aquaporin-2 (AQP2) water channel insertion in the apical membrane of principal cells, allowing water to passively flow along the osmotic gradient from the tubule lumen to the interstitium. In addition to short-term AQP2 redistribution between intracellular compartments and the cell surface, AQP2 whole cell abundance is tightly regulated. AVP is a major transcriptional activator of the AQP2 gene, and stimulation of insulin- and calcium-sensing receptors respectively potentiate and reduce its action. Extracellular tonicity is another key factor that determines the levels of AQP2 abundance. Its effect is dependent on activation of the tonicity-responsive enhancer binding protein that reinforces AVP-induced AQP2 transcriptional activation. Conversely, activation of the NF-κB transcriptional factor by proinflammatory factors reduces AQP2 gene transcription. Aldosterone additionally regulates AQP2 whole cell abundance by simultaneously reducing AQP2 gene transcription and stimulating AQP2 mRNA translation. These examples illustrate how cross talk between various stimuli regulates AQP2 abundance in collecting duct principal cells and consequently contributes to maintenance of body water homeostasis.
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Expression patterns of the aquaporin gene family during renal development: influence of genetic variability. Pflugers Arch 2009; 458:745-59. [PMID: 19367412 PMCID: PMC2756349 DOI: 10.1007/s00424-009-0667-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2009] [Accepted: 03/23/2009] [Indexed: 12/25/2022]
Abstract
High-throughput analyses have shown that aquaporins (AQPs) belong to a cluster of genes that are differentially expressed during kidney organogenesis. However, the spatiotemporal expression patterns of the AQP gene family during tubular maturation and the potential influence of genetic variation on these patterns and on water handling remain unknown. We investigated the expression patterns of all AQP isoforms in fetal (E13.5 to E18.5), postnatal (P1 to P28), and adult (9 weeks) kidneys of inbred (C57BL/6J) and outbred (CD-1) mice. Using quantitative polymerase chain reaction (PCR), we evidenced two mRNA patterns during tubular maturation in C57 mice. The AQPs 1-7-11 showed an early (from E14.5) and progressive increase to adult levels, similar to the mRNA pattern observed for proximal tubule markers (Megalin, NaPi-IIa, OAT1) and reflecting the continuous increase in renal cortical structures during development. By contrast, AQPs 2-3-4 showed a later (E15.5) and more abrupt increase, with transient postnatal overexpression. Most AQP genes were expressed earlier and/or stronger in maturing CD-1 kidneys. Furthermore, adult CD-1 kidneys expressed more AQP2 in the collecting ducts, which was reflected by a significant delay in excreting a water load. The expression patterns of proximal vs. distal AQPs and the earlier expression in the CD-1 strain were confirmed by immunoblotting and immunostaining. These data (1) substantiate the clustering of important genes during tubular maturation and (2) demonstrate that genetic variability influences the regulation of the AQP gene family during tubular maturation and water handling by the mature kidney.
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García-Delgado M, Peral MJ, Durán JM, García-Miranda P, Calonge ML, Ilundáin AA. Ontogeny of Na+/l-carnitine transporter and of γ-trimethylaminobutyraldehyde dehydrogenase and γ-butyrobetaine hydroxylase genes expression in rat kidney. Mech Ageing Dev 2009; 130:227-33. [DOI: 10.1016/j.mad.2008.12.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2008] [Revised: 11/20/2008] [Accepted: 12/13/2008] [Indexed: 11/26/2022]
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22
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Affiliation(s)
- Tae-Hwan Kwon
- Water and Salt Research Center, Institute of Anatomy, University of Aarhus, 8000 Aarhus C, Denmark
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Combet S, Gouraud S, Gobin R, Berthonaud V, Geelen G, Corman B, Verbavatz JM. Aquaporin-2 downregulation in kidney medulla of aging rats is posttranscriptional and is abolished by water deprivation. Am J Physiol Renal Physiol 2008; 294:F1408-14. [PMID: 18367658 DOI: 10.1152/ajprenal.00437.2007] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Aging kidney is associated in humans and rodents with polyuria and reduced urine concentrating ability. In senescent female WAG/Rij rats, this defect is independent of arginine-vasopressin (AVP)/V(2) receptor/cAMP pathway. It has been attributed to underexpression and mistargeting of aquaporin-2 (AQP2) water channel in the inner medullary collecting duct (IMCD). We showed previously that dDAVP administration could partially correct this defect. Since AQP2 can also be regulated by AVP-independent pathways in water deprivation (WD), we investigated AQP2 and phosphorylated AQP2 (p-AQP2) regulation in thirsted adult (10 mo old) and senescent (30 mo old) female WAG/Rij rats. Following 2-day WD, urine flow rate decreased and urine osmolality increased in both groups. However, in agreement with significantly lower cortico-papillary osmotic gradient with aging, urine osmolality remained lower in senescent animals. WD induced sixfold increase of plasma AVP in all animals which, interestingly, did not result in higher papillary cAMP level. Following WD, AQP2 and p-AQP2 expression increased hugely in 10- and 30-mo-old rats and their mistargeting in old animals was corrected. Moreover, the age-related difference in AQP2 regulation was abolished after WD. To further investigate the mechanism of AQP2 underexpression with aging, AQP2 mRNA was quantified by real-time RT-PCR. In the outer medulla, preservation of AQP2 protein expression was achieved through increased AQP2 mRNA level in senescent rats. In the IMCD, no change in AQP2 mRNA was detected with aging but AQP2 protein expression was markedly lower in 30-mo-old animals. In conclusion, there is a posttranscriptional downregulation of AQP2 with aging, which is abolished by WD.
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Affiliation(s)
- S Combet
- CEA, Institut de Biologie et Technologies de Saclay and CNRS URA 2096, Orsay, France.
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Rojek A, Praetorius J, Frøkiaer J, Nielsen S, Fenton RA. A Current View of the Mammalian Aquaglyceroporins. Annu Rev Physiol 2008; 70:301-27. [DOI: 10.1146/annurev.physiol.70.113006.100452] [Citation(s) in RCA: 246] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Aleksandra Rojek
- The Water and Salt Research Center, Institute of Anatomy, University of Aarhus, 8000 Aarhus C, Denmark;
| | - Jeppe Praetorius
- The Water and Salt Research Center, Institute of Anatomy, University of Aarhus, 8000 Aarhus C, Denmark;
| | - Jørgen Frøkiaer
- The Water and Salt Research Center, Institute of Anatomy, University of Aarhus, 8000 Aarhus C, Denmark;
| | - Søren Nielsen
- The Water and Salt Research Center, Institute of Anatomy, University of Aarhus, 8000 Aarhus C, Denmark;
| | - Robert A. Fenton
- The Water and Salt Research Center, Institute of Anatomy, University of Aarhus, 8000 Aarhus C, Denmark;
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Fenton RA, Knepper MA. Mouse models and the urinary concentrating mechanism in the new millennium. Physiol Rev 2007; 87:1083-112. [PMID: 17928581 DOI: 10.1152/physrev.00053.2006] [Citation(s) in RCA: 152] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Our understanding of urinary concentrating and diluting mechanisms at the end of the 20th century was based largely on data from renal micropuncture studies, isolated perfused tubule studies, tissue analysis studies and anatomical studies, combined with mathematical modeling. Despite extensive data, several key questions remained to be answered. With the advent of the 21st century, a new approach, transgenic and knockout mouse technology, is providing critical new information about urinary concentrating processes. The central goal of this review is to summarize findings in transgenic and knockout mice pertinent to our understanding of the urinary concentrating mechanism, focusing chiefly on mice in which expression of specific renal transporters or receptors has been deleted. These include the major renal water channels (aquaporins), urea transporters, ion transporters and channels (NHE3, NKCC2, NCC, ENaC, ROMK, ClC-K1), G protein-coupled receptors (type 2 vasopressin receptor, prostaglandin receptors, endothelin receptors, angiotensin II receptors), and signaling molecules. These studies shed new light on several key questions concerning the urinary concentrating mechanism including: 1) elucidation of the role of water absorption from the descending limb of Henle in countercurrent multiplication, 2) an evaluation of the feasibility of the passive model of Kokko-Rector and Stephenson, 3) explication of the role of inner medullary collecting duct urea transport in water conservation, 4) an evaluation of the role of tubuloglomerular feedback in maintenance of appropriate distal delivery rates for effective regulation of urinary water excretion, and 5) elucidation of the importance of water reabsorption in the connecting tubule versus the collecting duct for maintenance of water balance.
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Affiliation(s)
- Robert A Fenton
- Water and Salt Research Center, Institute of Anatomy, University of Aarhus, Aarhus, Denmark.
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García-Delgado M, García-Miranda P, Peral MJ, Calonge ML, Ilundáin AA. Ontogeny up-regulates renal Na(+)/Cl(-)/creatine transporter in rat. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2007; 1768:2841-8. [PMID: 17916324 DOI: 10.1016/j.bbamem.2007.07.022] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2007] [Revised: 07/23/2007] [Accepted: 07/27/2007] [Indexed: 11/28/2022]
Abstract
Creatine plays a role in energy storage and transport/shuttle of high-energy phosphate in heart, brain, retina, testis and skeletal muscle. These tissues take creatine from the plasma via a 2Na(+)/1Cl(-)/1creatine cotransporter (CRT). We have previously demonstrated that renal apical membrane presents a 2Na(+)/1Cl(-)/1creatine cotransport activity. The goal of this study was to determine whether this transporter is ontogenically regulated. Na(+)/Cl(-)/creatine transport activity was evaluated by measuring [(14)C]-creatine uptake into renal brush-border membrane vesicles. CRT mRNA expression was measured by Northern and real-time PCR assays. E20 foetuses, newborn, suckling, weaning and adult (2- and 8-month-old) Wistar rats were used. The results revealed that neither the vesicular volume, the binding of creatine to the brush-border membrane vesicles, nor the purity of the brush-border membrane vesicle preparations was affected by maturation. Fetal and neonatal kidneys contained a creatine transporter that was qualitatively indistinguishable from that in the adult: it was concentrative, Na(+)- and Cl(-)-dependent, electrogenic and inhibited by guanidinopropionic acid. Maturation increased this transport activity by increasing the maximal rate of transport (V(max)) without significantly changing the apparent K(m). Northern analysis revealed two transcripts for CRT of 2.7 kb and 4.2 kb in all the ages tested. Northern and real-time PCR assays showed that, as seen with NaCl-dependent creatine transport activity, maturation increased CRT mRNA expression. This study reports for the first time that: (i) an apical renal Na(+)/Cl(-)/creatine cotransporter is already active in rat foetuses and (ii) development regulates Na(+)/Cl(-)/creatine cotransport activity by increasing the density and/or turnover of the transporters.
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Affiliation(s)
- M García-Delgado
- Departamento de Fisiología y Zoología, Facultad de Farmacia, Universidad de Sevilla, Sevilla, Spain
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Hadrup N, Petersen JS, Windfeld S, Risom L, Andersen CB, Nielsen S, Christensen S, Jonassen TEN. Differential Down-Regulation of Aquaporin-2 in Rat Kidney Zones by Peripheral Nociceptin/Orphanin FQ Receptor Agonism and Vasopressin Type-2 Receptor Antagonism. J Pharmacol Exp Ther 2007; 323:516-24. [PMID: 17693587 DOI: 10.1124/jpet.107.123588] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We previously showed that aquaresis induced by the peripherally acting nociceptin/orphanin FQ receptor agonist ZP120 is associated with a decreased protein level of aquaporin-2 (AQP2) in whole-kidney homogenates. We now examined the effects of Ac-RYYRWKKKKKKK-NH(2) (ZP120) (1 nmol/kg/min i.v. for 4 h) on renal regional expression (cortex/outer stripe of outer medulla, inner stripe of outer medulla, and inner medulla) and subcellular localization of aquaporin-2. Responses to ZP120 were compared to the effects of an equi-aquaretic dose ( approximately 40% inhibition of distal water reabsorption) of the vasopressin type-2 receptor antagonist 5-dimethylamine-1-[4-(2-methylbenzoylamino)benzoyl]-2,3,4,5-tetrahydro-1H-benzapine (OPC31260) (32 nmol/kg/min). ZP120 decreased the aquaporin-2 protein level in the rat cortex/outer stripe of outer medulla and decreased apical plasma membrane localization of aquaporin-2 in the cortex (P = 0.002) and in the inner medulla (P = 0.06). These effects were not accompanied by a decrease in the aquaporin-2 mRNA level. OPC31260-induced aquaresis was associated with a decreased aquaporin-2 protein level in both the cortex/outer stripe of outer medulla and in the inner stripe of outer medulla. Apical localization of aquaporin-2 was decreased throughout all kidney zones, and OPC31260 decreased the AQP2 mRNA level in the inner medulla. We conclude that equi-aquaretic doses of ZP120 and OPC31260 produce different patterns of aquaporin-2 down-regulation, suggesting different signaling pathways.
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Affiliation(s)
- Niels Hadrup
- Department of Pharmacology, University of Copenhagen, Blegdamsvej 3, 2200 Copenhagen N, Denmark.
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Echevarría M, Muñoz-Cabello AM, Sánchez-Silva R, Toledo-Aral JJ, López-Barneo J. Development of cytosolic hypoxia and hypoxia-inducible factor stabilization are facilitated by aquaporin-1 expression. J Biol Chem 2007; 282:30207-15. [PMID: 17673462 DOI: 10.1074/jbc.m702639200] [Citation(s) in RCA: 98] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
O(2) is essential for aerobic life, and the classic view is that it diffuses freely across the plasma membrane. However, measurements of O(2) permeability of lipid bilayers have indicated that it is much lower than previously thought, and therefore, the existence of membrane O(2) channels has been suggested. We hypothesized that, besides its role as a water channel, aquaporin-1 (AQP-1) could also work as an O(2) transporter, because this transmembrane protein appears to be CO(2)-permeable and is highly expressed in cells with rapid O(2) turnover (erythrocytes and microvessel endothelium). Here we show that in mammalian cells overexpressing AQP-1 and exposed to hypoxia, the loss of cytosolic O(2), as well as stabilization of the O(2)-dependent hypoxia-inducible transcription factor and expression of its target genes, is accelerated. In normoxic endothelial cells, knocking down AQP-1 produces induction of hypoxia-inducible genes. Moreover, lung AQP-1 is markedly up-regulated in animals exposed to hypoxia. These data suggest that AQP-1 has O(2) permeability and thus could facilitate O(2) diffusion across the cell membrane.
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Affiliation(s)
- Miriam Echevarría
- Laboratorio de Investigaciones Biomédicas, Departamento de Fisiología Médica y Biofísica, Hospital Universitario Virgen del Rocío, Universidad de Sevilla, Sevilla, 41013 Spain
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Kennedy CRJ, Xiong H, Rahal S, Vanderluit J, Slack RS, Zhang Y, Guan Y, Breyer MD, Hébert RL. Urine concentrating defect in prostaglandin EP1-deficient mice. Am J Physiol Renal Physiol 2007; 292:F868-75. [PMID: 16885154 DOI: 10.1152/ajprenal.00183.2005] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We investigated the role of the prostaglandin E2(PGE2) EP1receptor in modulating urine concentration as it is expressed along the renal collecting duct where arginine-vasopressin (AVP) exerts its anti-diuretic activity, and in the paraventricular and supraoptic nuclei of the hypothalamus where AVP is synthesized. The urine osmolality of EP1-null mice (EP1−/−) failed to match levels achieved by wild-type (WT) counterparts upon water deprivation (WD) for 24 h. This difference was reflected by higher plasma osmolality in WD EP1−/−mice. Along the collecting duct, the induction and subapical to plasma membrane translocation of the aquaporin-2 water channel in WD EP1−/−mice appeared equivalent to that of WD WT mice as determined by quantitative RT-PCR and immunohistochemistry. However, medullary interstitial osmolalities dropped significantly in EP1−/−mice following WD. Furthermore, urinary AVP levels of WD EP1−/−mice were significantly lower than those of WD WT mice. This deficit could be traced back to a blunted induction of hypothalamic AVP mRNA expression in WD EP1−/−mice as determined by quantitative RT-PCR. Administration of the AVP mimetic [deamino-Cys1,d-Arg8]-vasopressin restored a significant proportion of the urine concentrating ability of WD EP1−/−mice. When mice were water loaded to suppress endogenous AVP production, urine osmolalities increased equally for WT and EP1−/−mice. These data suggest that PGE2modulates urine concentration by acting at EP1receptors, not in the collecting duct, but within the hypothalamus to promote AVP synthesis in response to acute WD.
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Lee J, Kim S, Kim J, Jeong MH, Oh Y, Choi KC. Increased Expression of Renal Aquaporin Water Channels in Spontaneously Hypertensive Rats. Kidney Blood Press Res 2006; 29:18-23. [PMID: 16582573 DOI: 10.1159/000092483] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2005] [Accepted: 12/22/2005] [Indexed: 11/19/2022] Open
Abstract
AIMS The present study was aimed to determine whether there exists an altered regulation of aquaporin (AQP) water channels in hypertension. METHODS Male spontaneously hypertensive rats (SHR) aged 10-12 weeks were used. Age-matched Wistar-Kyoto (WKY) rats served as control. The abundance of AQP1-4 proteins in the kidney was determined by Western blot analysis. The protein expression and activity of adenylyl cyclase were also determined. RESULTS The medullary expression of AQP2 and AQP3 proteins was increased in SHR compared with that in WKY rats. The expression of AQP1 protein was also significantly increased in the inner medulla, while that of AQP4 was not. Immunohistochemistry of AQP2 revealed that principal cells of the collecting duct have strong immunoreactivity, the degree of which was augmented with prominent apical labeling in SHR. The plasma level of arginine vasopressin (AVP) was higher in SHR; the adenylyl cyclase activity stimulated by AVP was augmented, along with increased expression of type VI adenylyl cyclase. The urine was more concentrated with its volume decreased in SHR. CONCLUSION The expression of AQP1-3 channels is increased in the kidney, in association with enhanced activity of the AVP/cAMP pathway, in SHR.
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Affiliation(s)
- JongUn Lee
- Department of Physiology, Chonnam National University Medical School, Gwangju, Korea.
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Lee J, Yoo K, Kim SW, Jung KH, Ma SK, Lee YK, Kim WY, Kim J, Choi KC. Decreased expression of aquaporin water channels in denervated rat kidney. Nephron Clin Pract 2006; 103:p170-8. [PMID: 16636595 DOI: 10.1159/000092918] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2005] [Accepted: 01/01/2006] [Indexed: 11/19/2022] Open
Abstract
AIMS A neural mechanism regulating aquaporin (AQP) water channels in the kidney was investigated. METHODS Male Sprague-Dawley rats were used. Renal denervation was induced by painting the renal vessels with 10% phenol. The expression of AQP1-4 proteins was determined in the denervated and contralateral kidneys. The expression was also examined in rats which were renally denervated and subjected to water restriction or deoxycorticosterone acetate (DOCA)-salt treatment. RESULTS Following the unilateral denervation, tissue contents of norepinephrine were significantly decreased in the denervated kidney, while increased in the contralateral kidney. Accordingly, the expression of AQP1-4 proteins was decreased by 15-40% in the denervated kidney, and increased by 30-50% in the contralateral kidney. Immunohistochemistry of AQP2 confirmed its decreases in the denervated kidney and increases in the contralateral kidney. In bilaterally denervated rats, the urine flow increased along with decreased osmolarity. The water restriction increased the expression of AQP channels, however, the magnitude of which was lower in the denervated than in the contralateral kidney. Renal denervation decreased the degree of DOCA-salt hypertension, along with lower expression of AQP channels. CONCLUSION It is suggested that the sympathetic nerve should play a specific excitatory role in the regulation of AQP channels in the kidney.
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Affiliation(s)
- JongUn Lee
- Department of Physiology, Chonnam National University Medical School, Gwangju, Korea.
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Llamas B, Contesse V, Guyonnet-Duperat V, Vaudry H, Mormède P, Moisan MP. QTL mapping for traits associated with stress neuroendocrine reactivity in rats. Mamm Genome 2006; 16:505-15. [PMID: 16151695 DOI: 10.1007/s00335-005-0022-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2005] [Accepted: 04/06/2005] [Indexed: 12/15/2022]
Abstract
In the present study we searched for quantitative trait loci (QTLs) that affect neuroendocrine stress responses in a 20-min restraint stress paradigm using Brown-Norway (BN) and Wistar-Kyoto-Hyperactive (WKHA) rats. These strains differed in their hypothalamic-pituitary-adrenal axis (plasma ACTH and corticosterone levels, thymus, and adrenal weights) and in their renin-angiotensin-aldosterone system reactivity (plasma renin activity, aldosterone concentration). We performed a whole-genome scan on a F2 progeny derived from a WKHA x BN intercross, which led to the identification of several QTLs linked to plasma renin activity (Sr6, Sr8, Sr11, and Sr12 on chromosomes RNO2, 3, 19, and 8, respectively), plasma aldosterone concentration (Sr7 and Sr9 on RNO2 and 5, respectively), and thymus weight (Sr10, Sr13, and Srl4 on RNO5, 10, and 16, respectively). The type 1b angiotensin II receptor gene (Agtrlb) maps within the confidence intervals of QTLs on RNO2 linked to plasma renin activity (Sr6, highly significant; LOD = 5.0) and to plasma aldosterone level (Sr7, suggestive; LOD = 2.0). In vitro studies of angiotensin II-induced release of aldosterone by adrenal glomerulosa cells revealed a lower receptor potency (log EC50 = -8.16 +/- 0.11 M) and efficiency (Emax = 453.3 +/- 25.9 pg/3 x 10(4) cells/24 h) in BN than in WKHA (log EC50 = -10.66 +/- 0.18 M; Emax = 573.1 +/- 15.3 pg/3 x 10(4) cells/24 h). Moreover, differences in Agtr1b mRNA abundance and sequence reinforce the putative role of the Agtr1b gene in the differential plasma renin stress reactivity between the two rat strains.
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Affiliation(s)
- Bastien Llamas
- Laboratoire Neurogénétique et Stress, INSERM U471/INRA UMR1243, Université Victor Segalen Bordeaux 2, Institut François Magendie, Rue Camille Saint Saens, 33077 Bordeaux cedex, France
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Yang B, Zhao D, Qian L, Verkman AS. Mouse model of inducible nephrogenic diabetes insipidus produced by floxed aquaporin-2 gene deletion. Am J Physiol Renal Physiol 2006; 291:F465-72. [PMID: 16434568 DOI: 10.1152/ajprenal.00494.2005] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Transgenic mouse models of defective urinary concentrating ability produced by deletion of various membrane transport or receptor proteins, including aquaporin-2 (AQP2), are associated with neonatal mortality from polyuria. Here, we report an inducible mouse model of AQP2 gene deletion with severe polyuria in adult mice. LoxP sequences were inserted into introns 1 and 2 in the mouse AQP2 gene by homologous recombination in embryonic stem cells. Mating of germ-line AQP2-loxP mice with tamoxifen-inducible Cre-expressing mice produced offspring with inducible homozygous Cre-AQP2-loxP, which had a normal phenotype. Tamoxifen injections over 10 days resulted in AQP2 gene excision, with undetectable full-length AQP2 transcript in kidney and a >95% reduction in immunoreactive AQP2 protein. Urine osmolality decreased from approximately 2,000 to <500 mosmol/kgH(2)O after 4-5 days, with urine output increasing from 2 to 25 ml/day. Urine osmolality did not increase after water deprivation. Interestingly, AQP3 protein expression in the collecting duct was increased by about fivefold after AQP2 gene excision. Mild renal damage was seen after 6 wk of polyuria, with collecting duct dilatation, yet normal creatinine clearance and serum chemistries. These results establish the first adult model of nephrogenic diabetes insipidus (NDI) caused by AQP2 deficiency, with daily urine output comparable to body weight, although remarkable preservation of renal function compared with non-inducible NDI models.
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Affiliation(s)
- Baoxue Yang
- Department of Medicine, Cardiovascular Research Institute, University of California, San Francisco, California 94143-0521, USA.
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Hasler U, Nielsen S, Féraille E, Martin PY. Posttranscriptional control of aquaporin-2 abundance by vasopressin in renal collecting duct principal cells. Am J Physiol Renal Physiol 2005; 290:F177-87. [PMID: 15985652 DOI: 10.1152/ajprenal.00056.2005] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Prevailing expression levels of aquaporin-2 (AQP2) mRNA play a major role in regulating AQP2 protein abundance. Here, we investigated whether AQP2 protein abundance is regulated at a posttranscriptional level as well. The expression levels of both AQP2 mRNA and protein increase in response to arginine vasopressin (AVP) in a concentration- and time-dependent manner in cultured immortalized mouse collecting duct principal cells (mpkCCD(cl4) cells). AVP washout from the medium of AVP-pretreated cells revealed that AQP2 mRNA expression progressively decreased over time, whereas AQP2 protein abundance first increased immediately after AVP washout and then gradually decreased over time. Inversely, increasing AVP concentration led to a time-dependent increase of AQP2 mRNA, whereas AQP2 protein abundance first decreased immediately after AVP supplementation and then gradually increased over time. These transient effects arose from altered V2-receptor activity because they could be abolished by SR-121463B, a specific V2-receptor antagonist. Although cycloheximide administration had no effect on transient alterations of AQP2 protein content, these effects were attenuated by administration of chloroquine, a lysosomal inhibitor, or lactacystin, a proteasomal inhibitor. Short-term inhibition of PKA activity significantly increased AQP2 protein abundance and blunted the transient alterations of AQP2 protein content induced by AVP washout and supplementation. In addition, phosphorylated AQP2 abundance increased immediately after AVP supplementation. These results indicate that in response to AVP AQP2 protein abundance in collecting duct principal cells is principally influenced by AQP2 mRNA content but is additionally regulated by PKA-dependent negative feedback acting on AQP2 protein degradation.
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Affiliation(s)
- Udo Hasler
- Service de Néphrologie, Fondation pour Recherches Médicales, 64 Ave. de la Roseraie, CH-1211, Genève 4, Switzerland
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Leung JC, Chan LY, Tsang AW, Tang SC, Lai KN. Differential expression of aquaporins in the kidneys of streptozotocin-induced diabetic mice. Nephrology (Carlton) 2005; 10:63-72. [PMID: 15705184 DOI: 10.1111/j.1440-1797.2005.00359.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND AND AIM Aquaporins (AQPs) are members of the water channel family and are important in renal physiology as it affects urinary concentration. The downregulation of aquaporins is often observed in polyuria associated with acquired nephrogenic diabetes insipidus. In this study, we examined the expression of AQP1, AQP2, AQP3 and AQP4 in streptozotocin (STZ)-induced diabetic mice. RESULTS By semiquantitative reverse transcription-polymerase chain reaction, we detected no change in the gene expression of AQP1 or AQP4 in whole kidney among STZ-induced diabetic mice (STZ mice) and sham (control group that received citrate buffer injection only). In contrast, we found less AQP2 or AQP3 mRNA expression in the whole kidney from STZ mice. Immunoblotting studies confirmed no difference in AQP1 or AQP4 protein expression of whole kidney between STZ mice and sham. However, there was less AQP2 or AQP3 protein expression in the whole kidney from STZ mice as compared to sham. By immunochemical staining, the reduction of AQP2 protein was localized to the principle cells of the collecting ducts. The expression of cortical AQP3 (especially the outer cortex, the S1 and S2 segments of the proximal tubules) was downregulated in STZ mice whereas the expression of AQP3 protein in medullary collecting ducts was similar to that of sham. CONCLUSION Our results reveal that the water transport in urinary concentration involves the downregulation of AQP2 and AQP3 expression in STZ mice.
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Affiliation(s)
- Joseph Ck Leung
- Division of Nephrology, Department of Medicine, Queen Mary Hospital, The University of Hong Kong, Pokfulam, Hong Kong
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Tian Y, Serino R, Verbalis JG. Downregulation of renal vasopressin V2 receptor and aquaporin-2 expression parallels age-associated defects in urine concentration. Am J Physiol Renal Physiol 2004; 287:F797-805. [PMID: 15213068 DOI: 10.1152/ajprenal.00403.2003] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Renal concentrating ability is known to be impaired with aging. The antidiuretic hormone AVP plays an important role in renal water excretion by regulating the membrane insertion and abundance of the water channel aquaporin-2 (AQP2); this effect is primarily mediated via the V2 subtype of the AVP receptor (V2R). This study evaluated the hypothesis that decreased renal sensitivity to AVP, with subsequent altered renal AQP2 expression, contributes to the reduced urinary concentrating ability with aging. Our results show that under baseline conditions, urine osmolality is significantly lower in aged Fischer 344 and Brown-Norway F1 hybrid (F344BN) rats despite equivalent plasma AVP concentrations as in young rats. Levels of kidney V2R mRNA expression and AQP2 abundances were also significantly decreased in aged F344BN rats, as was AQP2 immunostaining in collecting duct cells. In response to moderate water restriction, urine osmolality increased by significantly lesser amounts in aged F344BN rats compared with young rats despite similar increases in plasma AVP levels. Moderate water restriction induced equivalent relative increases in renal AQP2 abundances in all age groups but resulted in significantly lower abundances in total kidney AQP2 protein in aged compared with young F344BN rats. These results therefore demonstrate a functional impairment of renal concentrating ability in aged F344BN rats that is not due to impaired secretion of AVP but rather appears to be related to impaired responsiveness of the kidney to AVP that is secondary, at least in part, to a downregulation of renal V2R expression and AQP2 abundance.
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Affiliation(s)
- Ying Tian
- Division of Endocrinology and Metabolism, Department of Medicine, Georgetown University, Washington, DC 20007, USA.
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Bouby N, Fernandes S. Mild dehydration, vasopressin and the kidney: animal and human studies. Eur J Clin Nutr 2003; 57 Suppl 2:S39-46. [PMID: 14681712 DOI: 10.1038/sj.ejcn.1601900] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Water balance depends essentially on fluid intake and urine excretion. Mild dehydration and the consequent hypertonicity of the extracellular fluid induce an increase in vasopressin secretion, thus stimulating urine concentrating processes and the feeling of thirst. The osmotic threshold for the release of vasopressin is lower than that for thirst and also shows appreciable individual variation. Sustained high levels of vasopressin and low hydration induce morphological and functional changes in the kidney. However, they could also be risk factors in several renal disorders, such as chronic renal failure, diabetic nephropathy and salt-sensitive hypertension.
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Affiliation(s)
- N Bouby
- INSERM U 367, Paris, France.
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Trinh-Trang-Tan MM, Geelen G, Teillet L, Corman B. Urea transporter expression in aging kidney and brain during dehydration. Am J Physiol Regul Integr Comp Physiol 2003; 285:R1355-65. [PMID: 12933359 DOI: 10.1152/ajpregu.00207.2003] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Aging is commonly associated with defective urine-concentrating ability. The present study examined how the kidney and the brain of senescent (30-mo-old) female WAG/Rij rats respond to dehydration induced by 2 days of water deprivation in terms of urea transporter (UT) regulation. In euhydrated situation, senescent rats exhibited similar vasopressin plasma level but lower urine osmolality and papillary urea concentration and markedly reduced kidney UT-A1, UT-A3, and UT-B1 abundances compared with adult (10-mo-old) rats. Senescent rats responded to dehydration similarly to adult rats by a sixfold increase in vasopressin plasma level. Their papillary urea concentration was doubled, without, however, attaining that of dehydrated adult rats. Such an enhanced papillary urea sequestration occurred with a great fall of both UT-A1 and UT-A3 abundances in the tip of inner medulla and an increased UT-A1 abundance in the base of inner medulla. UT-A2 and UT-B1 were unchanged. These data suggest that the inability of control and thirsted senescent rats to concentrate urine as much as their younger counterparts derives from lower papillary urea concentration. In aging brain, UT-B1 abundance was increased twofold together with a fourfold increase in aquaporin-4 abundance. Dehydration did not alter the abundance of these transporters.
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Affiliation(s)
- M-M Trinh-Trang-Tan
- Institut National de la Santé et de la Recherche Médicale U76, Institut National de Transfusion Sanguine, 6, rue Alexandre Cabanel, F-75015 Paris, France.
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Solenov EI, Nesterov VV, Baturina GS, Khodus GR, Ivanova LN. Effect of dDAVP on basolateral cell surface water permeability in the outer medullary collecting duct. EUROPEAN BIOPHYSICS JOURNAL : EBJ 2003; 32:614-9. [PMID: 12783226 DOI: 10.1007/s00249-003-0308-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2002] [Revised: 04/06/2003] [Accepted: 04/16/2003] [Indexed: 10/26/2022]
Abstract
We report a novel approach for assessing the volume of living cells which allows quantitative, high-resolution characterization of dynamic changes in cell volume while retaining the cell functionality. The aim of this study was to evaluate the short-term effect of vasopressin on basolateral cell surface water permeability in the outer medullary collecting duct (OMCD). The permeability of the basolateral cell membrane was determined in the tubules where the apical membrane was blocked with oil injected into the lumen. The apparent coefficient of water permeability (Pf) was evaluated by measuring the cell swelling after the step from hypertonic to isotonic medium (600 mosm to 300 mosm). Desmopressin (dDAVP) induced an increase of the basolateral Pf from 113.7+/-8.5 microm/s in control cells to 186.6+/-11.4 mum/s in micro-dissected fragments of the OMCD incubated in vitro (10(-7) M dDAVP, 30 min at 37 degrees C) (P<0.05). Mercury caused pronounced inhibition of basolateral water permeability (26.0+/-6.9 microm/s; P<0.05). The effect of mercury (1.0 mM HgCl2) was reversible: after washing the fragments with PBS for 20 min, Pf values were restored to the control levels (125.0+/-9.5 microm/s). The results of the study indicate the existence of a mechanism controlling the osmotic water permeability of the basolateral cell membrane in the OMCD epithelium.
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Affiliation(s)
- E I Solenov
- Institute of Cytology and Genetics, Academy of Sciences of Russia, 630090 Novosibirsk, Russia.
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Tsujikawa T, Itoh A, Fukunaga T, Satoh J, Yasuoka T, Fujiyama Y. Alteration of aquaporin mRNA expression after small bowel resection in the rat residual ileum and colon. J Gastroenterol Hepatol 2003; 18:803-8. [PMID: 12795752 DOI: 10.1046/j.1440-1746.2003.03033.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/09/2022]
Abstract
BACKGROUND Diarrhea occurring after small bowel resection gradually improves due to intestinal adaptation. It is known that several water channels, termed aquaporins (AQP), are expressed in the gastrointestinal tract and facilitate water transport. However, the changes of AQP after bowel resection remain unclear. In the present paper, the alterations in AQP mRNA expression were investigated after a massive small bowel resection in the rat residual ileum and colon. METHODS The 6-week-old male Sprague-Dawley rats (n = 15) underwent an 80% distal small bowel resection. The residual ileum and colon were dissected on postoperative day 1, 3, 5 or 7 (n= 3 on each day). Total RNA was purified from each mucosa, and the expressions of AQP and sodium-dependent glucose transporter (SGLT1) mRNA were analyzed by northern blot. The plasma vasoactive intestinal polypeptide (VIP) concentrations on the preoperative day and postoperative day 1 were assayed. RESULTS In the residual small intestine, the expression of AQP-1 and AQP-3 mRNA increased significantly on postoperative day 1. The AQP-7 mRNA increased on postoperative day 3, but the AQP-4 mRNA did not change after the bowel resection. The SGLT1 mRNA gradually decreased after the bowel resection. In the colon, the expression of AQP-3 increased on postoperative day 1 and 7, but AQP-4 mRNA did not change after surgery. The AQP-8 mRNA levels increased slightly on postoperative day 7. Plasma VIP concentration did not change between preoperative day and postoperative day 1. CONCLUSIONS These results indicate that several AQP, except for AQP-4, were up-regulated after a massive small bowel resection, and that AQP might play important roles during adaptation.
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Affiliation(s)
- Tomoyuki Tsujikawa
- Division of Gastroenterology, Shiga University of Medical Science, Seta, Shiga, Japan
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Peral MJ, García-Delgado M, Calonge ML, Durán JM, De La Horra MC, Wallimann T, Speer O, Ilundáin A. Human, rat and chicken small intestinal Na+ - Cl- -creatine transporter: functional, molecular characterization and localization. J Physiol 2002; 545:133-44. [PMID: 12433955 PMCID: PMC2290665 DOI: 10.1113/jphysiol.2002.026377] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
In spite of all the fascinating properties of oral creatine supplementation, the mechanism(s) mediating its intestinal absorption has(have) not been investigated. The purpose of this study was to characterize intestinal creatine transport. [(14)C] creatine uptake was measured in chicken enterocytes and rat ileum, and expression of the creatine transporter CRT was examined in human, rat and chicken small intestine by reverse transcription-polymerase chain reaction, Northern blot, in situ hybridization, immunoblotting and immunohistochemistry. Results show that enterocytes accumulate creatine against its concentration gradient. This accumulation was electrogenic, Na(+)- and Cl(-)-dependent, with a probable stoichiometry of 2 Na(+): 1 Cl(-): 1 creatine, and inhibited by ouabain and iodoacetic acid. The kinetic study revealed a K(m) for creatine of 29 microM. [(14)C] creatine uptake was efficiently antagonized by non-labelled creatine, guanidinopropionic acid and cyclocreatine. More distant structural analogues of creatine, such as GABA, choline, glycine, beta-alanine, taurine and betaine, had no effect on intestinal creatine uptake, indicating a high substrate specificity of the creatine transporter. Consistent with these functional data, messenger RNA for CRT was detected only in the cells lining the intestinal villus. The sequences of partial clones, and of the full-length cDNA clone, isolated from human and rat small intestine were identical to previously cloned CRT cDNAs. Immunological analysis revealed that CRT protein was mainly associated with the apical membrane of the enterocytes. This study reports for the first time that mammalian and avian enterocytes express CRT along the villus, where it mediates high-affinity, Na(+)- and Cl(-)-dependent, apical creatine uptake.
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Affiliation(s)
- M J Peral
- Depto. Fisiología y Biología Animal, Facultad de Farmacia, Universidad de Sevilla, 41012 Seville, Spain
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Nielsen S, Frøkiaer J, Marples D, Kwon TH, Agre P, Knepper MA. Aquaporins in the kidney: from molecules to medicine. Physiol Rev 2002; 82:205-44. [PMID: 11773613 DOI: 10.1152/physrev.00024.2001] [Citation(s) in RCA: 853] [Impact Index Per Article: 38.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The discovery of aquaporin-1 (AQP1) answered the long-standing biophysical question of how water specifically crosses biological membranes. In the kidney, at least seven aquaporins are expressed at distinct sites. AQP1 is extremely abundant in the proximal tubule and descending thin limb and is essential for urinary concentration. AQP2 is exclusively expressed in the principal cells of the connecting tubule and collecting duct and is the predominant vasopressin-regulated water channel. AQP3 and AQP4 are both present in the basolateral plasma membrane of collecting duct principal cells and represent exit pathways for water reabsorbed apically via AQP2. Studies in patients and transgenic mice have demonstrated that both AQP2 and AQP3 are essential for urinary concentration. Three additional aquaporins are present in the kidney. AQP6 is present in intracellular vesicles in collecting duct intercalated cells, and AQP8 is present intracellularly at low abundance in proximal tubules and collecting duct principal cells, but the physiological function of these two channels remains undefined. AQP7 is abundant in the brush border of proximal tubule cells and is likely to be involved in proximal tubule water reabsorption. Body water balance is tightly regulated by vasopressin, and multiple studies now have underscored the essential roles of AQP2 in this. Vasopressin regulates acutely the water permeability of the kidney collecting duct by trafficking of AQP2 from intracellular vesicles to the apical plasma membrane. The long-term adaptational changes in body water balance are controlled in part by regulated changes in AQP2 and AQP3 expression levels. Lack of functional AQP2 is seen in primary forms of diabetes insipidus, and reduced expression and targeting are seen in several diseases associated with urinary concentrating defects such as acquired nephrogenic diabetes insipidus, postobstructive polyuria, as well as acute and chronic renal failure. In contrast, in conditions with water retention such as severe congestive heart failure, pregnancy, and syndrome of inappropriate antidiuretic hormone secretion, both AQP2 expression levels and apical plasma membrane targetting are increased, suggesting a role for AQP2 in the development of water retention. Continued analysis of the aquaporins is providing detailed molecular insight into the fundamental physiology and pathophysiology of water balance and water balance disorders.
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Affiliation(s)
- Søren Nielsen
- The Water and Salt Research Center, Institute of Anatomy, and Institute of Experimental Clinical Research, University of Aarhus, Aarhus, Denmark.
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Gallardo P, Cid LP, Vio CP, Sepúlveda FV. Aquaporin-2, a regulated water channel, is expressed in apical membranes of rat distal colon epithelium. Am J Physiol Gastrointest Liver Physiol 2001; 281:G856-63. [PMID: 11518698 DOI: 10.1152/ajpgi.2001.281.3.g856] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Aquaporin-2 (AQP-2) is the vasopressin-regulated water channel expressed in the apical membrane of principal cells in the collecting duct and is involved in the urinary concentrating mechanism. In the rat distal colon, vasopressin stimulates water absorption through an unknown mechanism. With the hypothesis that AQP-2 could contribute to this vasopressin effect, we studied its presence in rat colonic epithelium. We used RT-PCR, in situ hybridization, immunoblotting, and immunocytochemistry to probe for AQP-2 expression. An AQP-2 amplicon was obtained through RT-PCR of colon epithelium RNA, and in situ hybridization revealed AQP-2 mRNA in colonic crypts and, to a lesser extent, in surface absorptive epithelial cells. AQP-2 protein was localized to the apical membrane of surface absorptive epithelial cells, where it colocalized with H(+)-K(+)-ATPase but not with Na(+)-K(+)-ATPase. AQP-2 was absent from the small intestine, stomach, and liver. Water deprivation increased the hybridization signal and the protein level (assessed by Western blot analysis) for AQP-2 in distal colon. This was accompanied by increased p-chloromercuriphenylsulfonic acid-sensitive water absorption. These results indicate that AQP-2 is present in the rat distal colon, where it might be involved in a water-sparing mechanism. In addition, these results support the idea that AQP-2, and probably other aquaporins, are involved in water absorption in the colon.
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Affiliation(s)
- P Gallardo
- Centro de Estudios Científicos, Valdivia, Chile.
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Schnuelle P, Berger S, de Boer J, Persijn G, van der Woude FJ. Effects of catecholamine application to brain-dead donors on graft survival in solid organ transplantation. Transplantation 2001; 72:455-63. [PMID: 11502976 DOI: 10.1097/00007890-200108150-00017] [Citation(s) in RCA: 140] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
BACKGROUND In a recent single-center study, donor use of catecholamines was identified to reduce kidney allograft rejection. This study investigates the effects of donor employment of adrenergic agents on graft survival in a large data base, including liver and heart transplants. METHODS The study was based on the registry of the Eurotransplant International Foundation including 2415 kidney, 755 liver, and 720 heart transplants performed between January 1 and December 31, 1993. A total of 1742 donor record forms referring to the cadaveric donor activities in 1993 were systematically reviewed with regard to employment of adrenergic agents. Catecholamine use was simply coded dichotomously and divided into three strata according to zero, single, and combined application. Multivariate Cox regression including age, gender, cause of brain death, cold ischemia, HLA-mismatching, number of previous transplants, and urgency in liver transplants was applied for statistical analysis. RESULTS Donor employment of catecholamines was associated with increased 4-year graft survival after kidney transplantation (hazard ratio [HR], 0.85; 95% confidence interval [95% CI], 0.74-0.98). The benefit is conferred in a dose-dependent manner and compares in quantitative terms with prospective HLA matching on class I and class II antigens (HR, 0.90; 95% CI, 0.84-0.97). Use of norepinephrine was predictive of initial nonfunction after heart transplantation (HR, 1.66; 95% CI, 1.14-2.43), but did not compromise liver grafts (HR, 0.94; 95% CI, 0.67-1.32). CONCLUSIONS Optimizing the management of brain-dead organ donors, including the possibility of selective administration of adrenergic agents, may provide a major benefit on graft survival without adverse side effects for the recipients. Further investigation on best use of adrenergic drugs, optimum dosage, and duration is warranted.
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Affiliation(s)
- P Schnuelle
- University Hospital Mannheim, Theodor Kutzer Ufer 1-3, 68167 Mannheim, Germany.
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Pedersen RS, Bentzen H, Bech JN, Pedersen EB. Effect of water deprivation and hypertonic saline infusion on urinary AQP2 excretion in healthy humans. Am J Physiol Renal Physiol 2001; 280:F860-7. [PMID: 11292629 DOI: 10.1152/ajprenal.2001.280.5.f860] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Arginine vasopressin (AVP) mediates water transport in the renal collecting ducts by forming water channels of aquaporin-2 (AQP2) in the apical plasma membrane. AQP2 is excreted in human urine. We wanted to test the hypothesis that urinary excretion of AQP2 (u-AQP2) reflects the effect of AVP on the renal collecting ducts during water deprivation and hypertonic saline infusion in healthy subjects. Fifteen healthy subjects underwent a 24-h period of fluid restriction. Urine and blood samples were collected at timed intervals. Fifteen healthy subjects were given 7 ml/kg 3% hypertonic saline infusion for 30 min. Urine and blood samples were collected at timed intervals. During fluid restriction, the u-AQP2 rate increased from 3.9 (25th percentile: 3.1; 75th percentile: 5.2) to 7.6 (5.9-9.1; P < 0.001) ng/min, and the plasma AVP (p-AVP) level increased from 0.5 (0.4-0.6) to 3 (1.7-3.3) pmol/l. There was a positive correlation between the maximum change in u-AQP2 rate and the maximum change in p-AVP (r = 0.57, P < 0.03). During the infusion study, u-AQP2 rate was at maximum 90 min after the infusion [baseline: 4.5 ng/min (3.5-4.8); 90 min: 5 ng/min (4.5-6.0) P < 0.02]. p-AVP increased from 1.0 (0.9-1.1) to 1.5 (1.2-1.8; P < 0.002) pmol/l. There was a positive correlation between the maximum change in u-AQP2 rate and the maximum change in p-AVP (r = 0.83; P < 0.0001). It can be concluded that p-AVP and u-AQP2 are increased during thirst and hypertonic saline infusion and that u-AQP2 reflects the action of AVP on the collecting ducts.
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Affiliation(s)
- R S Pedersen
- Department of Medicine, Holstebro Hospital, DK-7500 Holstebro, Denmark.
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