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Sun Z, Shao X, Wu H, Zhao Y, Cao Y, Li D, Sun Y, Wang Q. Loss of Pten in Renal Tubular Cells Leads to Water Retention by Upregulating AQP2. KIDNEY DISEASES (BASEL, SWITZERLAND) 2022; 9:58-71. [PMID: 36756085 PMCID: PMC9900467 DOI: 10.1159/000528010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/12/2022] [Accepted: 10/26/2022] [Indexed: 12/02/2022]
Abstract
Introduction Phosphatase and tensin (PTEN) is a multifunctional gene associated with the normal development and physiological function of various tissues including the kidney. However, its role in renal tubular reabsorption function has not been well elucidated. Methods We generated a renal tubule-specific Pten knockout mouse model by crossing Ptenfl/fl mice with Ksp-Cre transgenic mice, evaluated the effect of Pten loss on renal tubular function, and investigated the underlying mechanisms. Results Pten loss resulted in abnormal renal structure and function and water retention in multiple organs. Our results also demonstrated that aquaporin-2 (AQP2), an important water channel protein, was upregulated and concentrated on the apical plasma membrane of collecting duct cells, which could be responsible for the impaired water balance in Pten loss mice. The regulation of Pten loss on AQP2 was mediated by protein kinase B (AKT) activation. Conclusions Our results reveal a connection between PTEN gene inactivation and water retention, suggesting the importance of PTEN in normal kidney development and function.
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Affiliation(s)
- Zhuo Sun
- Department of Pathology, Laboratory of Clinical and Experimental Pathology, Xuzhou Medical University, Xuzhou, China
| | - Xiaotong Shao
- Department of Pathology, Laboratory of Clinical and Experimental Pathology, Xuzhou Medical University, Xuzhou, China
| | - Haotian Wu
- Department of Pathology, Laboratory of Clinical and Experimental Pathology, Xuzhou Medical University, Xuzhou, China
| | - Yaxian Zhao
- Department of Pathology, Xuzhou Maternity and Child Health Care Hospital, Xuzhou, China
| | - Yidan Cao
- Department of Pathology, Wuxi No.2 People's Hospital, Wuxi, China
| | - Danhua Li
- Department of Pathology, Laboratory of Clinical and Experimental Pathology, Xuzhou Medical University, Xuzhou, China
| | - Ying Sun
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Xuzhou Medical University, Xuzhou, China
| | - Qingling Wang
- Department of Pathology, Laboratory of Clinical and Experimental Pathology, Xuzhou Medical University, Xuzhou, China,*Qingling Wang,
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Ribeiro JC, Bernardino RL, Carrageta DF, Soveral G, Calamita G, Alves MG, Oliveira PF. CFTR modulates aquaporin-mediated glycerol permeability in mouse Sertoli cells. Cell Mol Life Sci 2022; 79:592. [PMID: 36378343 DOI: 10.1007/s00018-022-04619-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Revised: 10/10/2022] [Accepted: 10/31/2022] [Indexed: 11/16/2022]
Abstract
The cystic fibrosis transmembrane conductance regulator (CFTR) is an anion channel that is crucial for fluid homeodynamics throughout the male reproductive tract. Previous evidence shed light on a potential molecular partnership between this channel and aquaporins (AQPs). Herein, we explore the role of CFTR on AQPs-mediated glycerol permeability in mouse Sertoli cells (mSCs). We were able to identify the expression of CFTR, AQP3, AQP7, and AQP9 in mSCs by RT-PCR, Western blot, and immunofluorescence techniques. Cells were then treated with CFTRinh-172, a specific CFTR inhibitor, and its glycerol permeability was evaluated by stopped-flow light scattering. We observed that CFTR inhibition decreased glycerol permeability in mSCs by 30.6% when compared to the control group. A DUOLINK proximity ligation assay was used to evaluate the endogenous protein-protein interactions between CFTR and the various aquaglyceroporins we identified. We positively detected that CFTR is in close proximity with AQP3, AQP7, and AQP9 and that, through a possible physical interaction, CFTR can modulate AQP-mediated glycerol permeability in mSCs. As glycerol is essential for the control of the blood-testis barrier and elevated concentration in testis results in the disruption of spermatogenesis, we suggest that the malfunction of CFTR and the consequent alteration in glycerol permeability is a potential link between male infertility and cystic fibrosis.
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Affiliation(s)
- João C Ribeiro
- Department of Anatomy, Unit for Multidisciplinary Research in Biomedicine (UMIB), Institute of Biomedical Sciences Abel Salazar (ICBAS), University of Porto, Porto, Portugal.,Laboratory for Integrative and Translational Research in Population Health (ITR), University of Porto, Porto, Portugal.,LAQV-REQUIMTE and Department of Chemistry, University of Aveiro, Aveiro, Portugal
| | - Raquel L Bernardino
- Department of Anatomy, Unit for Multidisciplinary Research in Biomedicine (UMIB), Institute of Biomedical Sciences Abel Salazar (ICBAS), University of Porto, Porto, Portugal.,Laboratory for Integrative and Translational Research in Population Health (ITR), University of Porto, Porto, Portugal
| | - David F Carrageta
- Department of Anatomy, Unit for Multidisciplinary Research in Biomedicine (UMIB), Institute of Biomedical Sciences Abel Salazar (ICBAS), University of Porto, Porto, Portugal.,Laboratory for Integrative and Translational Research in Population Health (ITR), University of Porto, Porto, Portugal
| | - Graça Soveral
- Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, Lisbon, Portugal
| | - Giuseppe Calamita
- Department of Biosciences, Biotechnologies and Environment, University of Bari "Aldo Moro", Bari, Italy
| | - Marco G Alves
- Department of Anatomy, Unit for Multidisciplinary Research in Biomedicine (UMIB), Institute of Biomedical Sciences Abel Salazar (ICBAS), University of Porto, Porto, Portugal.,Laboratory for Integrative and Translational Research in Population Health (ITR), University of Porto, Porto, Portugal.,Biotechnology of Animal and Human Reproduction (TechnoSperm), Institute of Food and Agricultural Technology, University of Girona, 17003, Girona, Spain.,Unit of Cell Biology, Department of Biology, Faculty of Sciences, University of Girona, 17003, Girona, Spain
| | - Pedro F Oliveira
- LAQV-REQUIMTE and Department of Chemistry, University of Aveiro, Aveiro, Portugal.
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Aquaporin Gating: A New Twist to Unravel Permeation through Water Channels. Int J Mol Sci 2022; 23:ijms232012317. [PMID: 36293170 PMCID: PMC9604103 DOI: 10.3390/ijms232012317] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2022] [Revised: 09/30/2022] [Accepted: 10/05/2022] [Indexed: 11/17/2022] Open
Abstract
Aquaporins (AQPs) are small transmembrane tetrameric proteins that facilitate water, solute and gas exchange. Their presence has been extensively reported in the biological membranes of almost all living organisms. Although their discovery is much more recent than ion transport systems, different biophysical approaches have contributed to confirm that permeation through each monomer is consistent with closed and open states, introducing the term gating mechanism into the field. The study of AQPs in their native membrane or overexpressed in heterologous systems have experimentally demonstrated that water membrane permeability can be reversibly modified in response to specific modulators. For some regulation mechanisms, such as pH changes, evidence for gating is also supported by high-resolution structures of the water channel in different configurations as well as molecular dynamics simulation. Both experimental and simulation approaches sustain that the rearrangement of conserved residues contributes to occlude the cavity of the channel restricting water permeation. Interestingly, specific charged and conserved residues are present in the environment of the pore and, thus, the tetrameric structure can be subjected to alter the positions of these charges to sustain gating. Thus, is it possible to explore whether the displacement of these charges (gating current) leads to conformational changes? To our knowledge, this question has not yet been addressed at all. In this review, we intend to analyze the suitability of this proposal for the first time.
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AQP2 trafficking in health and diseases: an updated overview. Int J Biochem Cell Biol 2022; 149:106261. [DOI: 10.1016/j.biocel.2022.106261] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Revised: 05/25/2022] [Accepted: 06/30/2022] [Indexed: 11/23/2022]
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A multiscale model of the regulation of aquaporin 2 recycling. NPJ Syst Biol Appl 2022; 8:16. [PMID: 35534498 PMCID: PMC9085758 DOI: 10.1038/s41540-022-00223-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Accepted: 03/24/2022] [Indexed: 11/08/2022] Open
Abstract
The response of cells to their environment is driven by a variety of proteins and messenger molecules. In eukaryotes, their distribution and location in the cell are regulated by the vesicular transport system. The transport of aquaporin 2 between membrane and storage region is a crucial part of the water reabsorption in renal principal cells, and its malfunction can lead to Diabetes insipidus. To understand the regulation of this system, we aggregated pathways and mechanisms from literature and derived three models in a hypothesis-driven approach. Furthermore, we combined the models to a single system to gain insight into key regulatory mechanisms of Aquaporin 2 recycling. To achieve this, we developed a multiscale computational framework for the modeling and simulation of cellular systems. The analysis of the system rationalizes that the compartmentalization of cAMP in renal principal cells is a result of the protein kinase A signalosome and can only occur if specific cellular components are observed in conjunction. Endocytotic and exocytotic processes are inherently connected and can be regulated by the same protein kinase A signal.
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Molecular mechanisms governing aquaporin relocalisation. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2022; 1864:183853. [PMID: 34973181 PMCID: PMC8825993 DOI: 10.1016/j.bbamem.2021.183853] [Citation(s) in RCA: 36] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 12/20/2021] [Accepted: 12/21/2021] [Indexed: 02/07/2023]
Abstract
The aquaporins (AQPs) form a family of integral membrane proteins that facilitate the movement of water across biological membrane by osmosis, as well as facilitating the diffusion of small polar solutes. AQPs have been recognised as drug targets for a variety of disorders associated with disrupted water or solute transport, including brain oedema following stroke or trauma, epilepsy, cancer cell migration and tumour angiogenesis, metabolic disorders, and inflammation. Despite this, drug discovery for AQPs has made little progress due to a lack of reproducible high-throughput assays and difficulties with the druggability of AQP proteins. However, recent studies have suggested that targetting the trafficking of AQP proteins to the plasma membrane is a viable alternative drug target to direct inhibition of the water-conducting pore. Here we review the literature on the trafficking of mammalian AQPs with a view to highlighting potential new drug targets for a variety of conditions associated with disrupted water and solute homeostasis. Aquaporins (AQPs) form water and solute permeable pores in biological membranes. AQPs represent attractive drug targets for disorders of water/solute homeostasis. Drug discovery efforts towards pore-blocking AQP inhibitors have made little progress. AQPs are dynamically relocalised between intracellular vesicles and plasma membrane. This relocalisation represents a new target for inhibition of AQP function.
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7
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Mu D, Ma C, Cheng J, Zou Y, Qiu L, Cheng X. Copeptin in fluid disorders and stress. Clin Chim Acta 2022; 529:46-60. [PMID: 35143773 DOI: 10.1016/j.cca.2022.02.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Revised: 01/30/2022] [Accepted: 02/02/2022] [Indexed: 12/16/2022]
Abstract
Copeptin, a glycosylated peptide of 39 amino acids, is the C-terminal segment of arginine vasopressin (AVP) precursor peptide, which is consisted of two other fragments, vasopressin and neurophysin Ⅱ. The main physiological functions of AVP are fluid and osmotic balance, cardiovascular homeostasis and regulation of the endocrine stress response. Numerous studies have demonstrated that the endogenous AVP in plasma is a meaningful biomarker to guide diagnosis and therapy of diseases associated with fluids disorders and stress. However, due to its instability, short half-time life in circulation and lack of readily available AVP assays, clinical measurement of AVP is restricted. In contrast to AVP, copeptin which is released in an equimolar mode with AVP from the pituitary, has emerged as a stable and simple-to-measure surrogate marker of AVP and displays excellent potential in diagnosis, differentiation and prognosis of various diseases. This review will discuss the studies on the clinical value of copeptin in different diseases, especially in AVP-dependent fluids disorders, as well as issues and prospects of the application of this potential biomarker.
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Affiliation(s)
- Danni Mu
- Department of Laboratory Medicine, Peking Union Medical College Hospital, Peking Union Medical College & Chinese Academy of Medical Science, Beijing 100730, China
| | - Chaochao Ma
- Department of Laboratory Medicine, Peking Union Medical College Hospital, Peking Union Medical College & Chinese Academy of Medical Science, Beijing 100730, China
| | - Jin Cheng
- Department of Laboratory Medicine, Peking Union Medical College Hospital, Peking Union Medical College & Chinese Academy of Medical Science, Beijing 100730, China
| | - Yutong Zou
- Department of Laboratory Medicine, Peking Union Medical College Hospital, Peking Union Medical College & Chinese Academy of Medical Science, Beijing 100730, China
| | - Ling Qiu
- Department of Laboratory Medicine, Peking Union Medical College Hospital, Peking Union Medical College & Chinese Academy of Medical Science, Beijing 100730, China; State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
| | - Xinqi Cheng
- Department of Laboratory Medicine, Peking Union Medical College Hospital, Peking Union Medical College & Chinese Academy of Medical Science, Beijing 100730, China.
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Shao L, Ma Y, Fang Q, Huang Z, Wan S, Wang J, Yang L. Role of protein phosphatase 2A in kidney disease (Review). Exp Ther Med 2021; 22:1236. [PMID: 34539832 PMCID: PMC8438693 DOI: 10.3892/etm.2021.10671] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Accepted: 01/06/2021] [Indexed: 12/12/2022] Open
Abstract
Kidney disease affects millions of people worldwide and is a financial burden on the healthcare system. Protein phosphatase 2A (PP2A), which is involved in renal development and the function of ion-transport proteins, aquaporin-2 and podocytes, is likely to serve an important role in renal processes. PP2A is associated with the pathogenesis of a variety of different kidney diseases including podocyte injury, inflammation, tumors and chronic kidney disease. The current review aimed to discuss the structure and function of PP2A subunits in the context of kidney diseases. How dysregulation of PP2A in the kidneys causes podocyte death and the inactivation of PP2A in renal carcinoma tissues is discussed. Inhibition of PP2A activity prevents epithelial-mesenchymal transition and attenuates renal fibrosis, creating a favorable inflammatory microenvironment and promoting the initiation and progression of tumor pathogenesis. The current review also indicates that PP2A serves an important role in protection against renal inflammation. Understanding the detailed mechanisms of PP2A provides information that can be utilized in the design and application of novel therapeutics for the treatment and prevention of renal diseases.
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Affiliation(s)
- Lishi Shao
- Department of Radiology, Kunming Medical University and The Second Affiliated Hospital, Kunming, Yunnan 650500, P.R. China
| | - Yiqun Ma
- Department of Radiology, Kunming Medical University and The Second Affiliated Hospital, Kunming, Yunnan 650500, P.R. China
| | - Qixiang Fang
- Department of Urology, The First Affiliated Hospital of the Medical College of Xi'an Jiaotong University, Xi'an, Shaanxi 710049, P.R. China
| | - Ziye Huang
- Department of Urology, Kunming Medical University and The Second Affiliated Hospital, Kunming, Yunnan 650500, P.R. China
| | - Shanshan Wan
- Department of Radiology, Yunnan Kun-Gang Hospital, Anning, Yunnan 650300, P.R. China
| | - Jiaping Wang
- Department of Radiology, Kunming Medical University and The Second Affiliated Hospital, Kunming, Yunnan 650500, P.R. China
| | - Li Yang
- Department of Anatomy, Histology and Embryology, Kunming Medical University, Kunming, Yunnan 650500, P.R. China
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9
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AQP3 and AQP5-Potential Regulators of Redox Status in Breast Cancer. Molecules 2021; 26:molecules26092613. [PMID: 33947079 PMCID: PMC8124745 DOI: 10.3390/molecules26092613] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 04/22/2021] [Accepted: 04/27/2021] [Indexed: 12/23/2022] Open
Abstract
Breast cancer is still one of the leading causes of mortality in the female population. Despite the campaigns for early detection, the improvement in procedures and treatment, drastic improvement in survival rate is omitted. Discovery of aquaporins, at first described as cellular plumbing system, opened new insights in processes which contribute to cancer cell motility and proliferation. As we discover new pathways activated by aquaporins, the more we realize the complexity of biological processes and the necessity to fully understand the pathways affected by specific aquaporin in order to gain the desired outcome-remission of the disease. Among the 13 human aquaporins, AQP3 and AQP5 were shown to be significantly upregulated in breast cancer indicating their role in the development of this malignancy. Therefore, these two aquaporins will be discussed for their involvement in breast cancer development, regulation of oxidative stress and redox signalling pathways leading to possibly targeting them for new therapies.
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10
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Fenton RA, Murali SK, Moeller HB. Advances in Aquaporin-2 trafficking mechanisms and their implications for treatment of water balance disorders. Am J Physiol Cell Physiol 2020; 319:C1-C10. [PMID: 32432927 DOI: 10.1152/ajpcell.00150.2020] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
In mammals, conservation of body water is critical for survival and is dependent on the kidneys ability to minimize water loss in the urine during periods of water deprivation. The collecting duct water channel aquaporin-2 (AQP2) plays an essential role in this homeostatic response by facilitating water reabsorption along osmotic gradients. The ability to increase the levels of AQP2 in the apical plasma membrane following an increase in plasma osmolality is a rate-limiting step in water reabsorption, a process that is tightly regulated by the antidiuretic hormone arginine vasopressin (AVP). In this review, the focus is on the role of the carboxyl-terminus of AQP2 as a key regulatory point for AQP2 trafficking. We provide an overview of AQP2 structure, disease-causing mutations in the AQP2 carboxyl-terminus, the role of post-translational modifications such as phosphorylation and ubiquitylation in the tail domain, and their implications for balanced trafficking of AQP2. Finally, we discuss how various modifications of the AQP2 tail facilitate selective protein:protein interactions that modulate the AQP2 trafficking mechanism.
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Affiliation(s)
- Robert A Fenton
- Department of Biomedicine, Aarhus University, Aarhus DK-8000, Denmark
| | - Sathish K Murali
- Department of Biomedicine, Aarhus University, Aarhus DK-8000, Denmark
| | - Hanne B Moeller
- Department of Biomedicine, Aarhus University, Aarhus DK-8000, Denmark
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Xu LH, Yang Y, Liu HX, Xiao SF, Qiu WX, Wang JX, Zhao CC, Gui YH, Liu GZ, Peng B, Li X, Wang GH, Zhou X, Jiang ZL. Inner Ear Arginine Vasopressin-Vasopressin Receptor 2-Aquaporin 2 Signaling Pathway Is Involved in the Induction of Motion Sickness. J Pharmacol Exp Ther 2020; 373:248-260. [PMID: 32165443 DOI: 10.1124/jpet.119.264390] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Accepted: 02/24/2020] [Indexed: 11/22/2022] Open
Abstract
It has been identified that arginine vasopressin (AVP), vasopressin receptor 2(V2R), and the aquaporin 2 (AQP2) signaling pathway in the inner ear play important roles in hearing and balance functions through regulating the endolymph equilibrium; however, the contributions of this signaling pathway to the development of motion sickness are unclear. The present study was designed to investigate whether the activation of the AVP-V2R-AQP2 signaling pathway in the inner ear is involved in the induction of motion sickness and whether mozavaptan, a V2R antagonist, could reduce motion sickness. We found that both rotatory stimulus and intraperitoneal AVP injection induced conditioned taste aversion (a confirmed behavioral index for motion sickness) in rats and activated the AVP-V2R-AQP2 signaling pathway with a responsive V2R downregulation in the inner ears, and AVP perfusion in cultured epithelial cells from rat endolymphatic sacs induced similar changes in this pathway signaling. Vestibular training, V2R antagonist mozavaptan, or PKA inhibitor H89 blunted these changes in the V2R-AQP2 pathway signaling while reducing rotatory stimulus- or DDAVP (a V2R agonist)-induced motion sickness in rats and dogs. Therefore, our results suggest that activation of the inner ear AVP-V2R-AQP2 signaling pathway is potentially involved in the development of motion sickness; thus, mozavaptan targeting AVP V2Rs in the inner ear may provide us with a new application option to reduce motion sickness. SIGNIFICANCE STATEMENT: Motion sickness affects many people traveling or working. In the present study our results showed that activation of the inner ear arginine vasopressin-vaspopressin receptor 2 (V2R)-aquaporin 2 signaling pathway was potentially involved in the development of motion sickness and that blocking V2R with mozavaptan, a V2R antagonist, was much more effective in reducing motion sickness in both rat and dog; therefore, we demonstrated a new mechanism to underlie motion sickness and a new candidate drug to reduce motion sickness.
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Affiliation(s)
- Li-Hua Xu
- Department of Neurophysiology and Neuropharmacology, Institute of Special Environmental Medicine, Institute of Nautical Medicine and Co-innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu, China
| | - Yao Yang
- Department of Neurophysiology and Neuropharmacology, Institute of Special Environmental Medicine, Institute of Nautical Medicine and Co-innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu, China
| | - Hong-Xia Liu
- Department of Neurophysiology and Neuropharmacology, Institute of Special Environmental Medicine, Institute of Nautical Medicine and Co-innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu, China
| | - Shui-Feng Xiao
- Department of Neurophysiology and Neuropharmacology, Institute of Special Environmental Medicine, Institute of Nautical Medicine and Co-innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu, China
| | - Wen-Xia Qiu
- Department of Neurophysiology and Neuropharmacology, Institute of Special Environmental Medicine, Institute of Nautical Medicine and Co-innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu, China
| | - Jin-Xing Wang
- Department of Neurophysiology and Neuropharmacology, Institute of Special Environmental Medicine, Institute of Nautical Medicine and Co-innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu, China
| | - Chen-Chen Zhao
- Department of Neurophysiology and Neuropharmacology, Institute of Special Environmental Medicine, Institute of Nautical Medicine and Co-innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu, China
| | - Yuan-Hong Gui
- Department of Neurophysiology and Neuropharmacology, Institute of Special Environmental Medicine, Institute of Nautical Medicine and Co-innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu, China
| | - Gui-Zhu Liu
- Department of Neurophysiology and Neuropharmacology, Institute of Special Environmental Medicine, Institute of Nautical Medicine and Co-innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu, China
| | - Bin Peng
- Department of Neurophysiology and Neuropharmacology, Institute of Special Environmental Medicine, Institute of Nautical Medicine and Co-innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu, China
| | - Xia Li
- Department of Neurophysiology and Neuropharmacology, Institute of Special Environmental Medicine, Institute of Nautical Medicine and Co-innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu, China
| | - Guo-Hua Wang
- Department of Neurophysiology and Neuropharmacology, Institute of Special Environmental Medicine, Institute of Nautical Medicine and Co-innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu, China
| | - Xin Zhou
- Department of Neurophysiology and Neuropharmacology, Institute of Special Environmental Medicine, Institute of Nautical Medicine and Co-innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu, China
| | - Zheng-Lin Jiang
- Department of Neurophysiology and Neuropharmacology, Institute of Special Environmental Medicine, Institute of Nautical Medicine and Co-innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu, China
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Dong SH, Kim SS, Kim SH, Yeo SG. Expression of aquaporins in inner ear disease. Laryngoscope 2019; 130:1532-1539. [PMID: 31593306 DOI: 10.1002/lary.28334] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Revised: 09/05/2019] [Accepted: 09/10/2019] [Indexed: 12/22/2022]
Abstract
The inner ear is responsible for hearing and balance and consists of a membranous labyrinth within a bony labyrinth. The balance structure is divided into the otolith organ that recognizes linear acceleration and the semicircular canal that is responsible for rotational movement. The cochlea is the hearing organ. The external and middle ear are covered with skin and mucosa, respectively, and the space is filled with air, whereas the inner ear is composed of endolymph and perilymph. The inner ear is a fluid-filled sensory organ composed of hair cells with cilia on the upper part of the cells that convert changes in sound energy and balance into electric energy through the hair cells to transmit signals to the auditory nerve through synapses. Aquaporins (AQPs) are a family of transmembrane proteins present in all species that can be roughly divided into three subfamilies according to structure and function: 1) classical AQP, 2) aquaglyceroporin, and 3) superaquaporin. Currently, the subfamily of mammalian species is known to include 13 AQP members (AQP0-AQP12). AQPs have a variety of functions depending on their structure and are related to inner ear diseases such as Meniere's disease, sensorineural hearing loss, and presbycusis. Additional studies on the relationship between the inner ear and AQPs may be helpful in the diagnosis and treatment of inner ear disease. Laryngoscope, 130:1532-1539, 2020.
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Affiliation(s)
- Sung Hwa Dong
- Department of Otorhinolaryngology-Head and Neck Surgery, Graduate School, Kyung Hee University, Seoul, South Korea
| | - Sung Su Kim
- Medical Research Center for Bioreaction to Reactive Oxygen Species and Biomedical Science Institute, School of Medicine, Graduate School, Kyung Hee University, Seoul, South Korea
| | - Sang Hoon Kim
- Department of Otorhinolaryngology-Head and Neck Surgery, Graduate School, Kyung Hee University, Seoul, South Korea
| | - Seung Geun Yeo
- Department of Otorhinolaryngology-Head and Neck Surgery, Graduate School, Kyung Hee University, Seoul, South Korea.,Medical Research Center for Bioreaction to Reactive Oxygen Species and Biomedical Science Institute, School of Medicine, Graduate School, Kyung Hee University, Seoul, South Korea
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Törnroth-Horsefield S. Phosphorylation of human AQP2 and its role in trafficking. VITAMINS AND HORMONES 2019; 112:95-117. [PMID: 32061351 DOI: 10.1016/bs.vh.2019.08.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Human Aquaporin 2 (AQP2) is a membrane-bound water channel found in the kidney collecting duct whose regulation by trafficking plays a key role in regulating urine volume. AQP2 trafficking is tightly controlled by the pituitary hormone arginine vasopressin (AVP), which stimulates translocation of AQP2 residing in storage vesicles to the apical membrane. The AVP-dependent translocation of AQP2 to and from the apical membrane is controlled by multiple phosphorylation sites in the AQP2 C-terminus, the phosphorylation of which alters its affinity to proteins within the cellular membrane protein trafficking machinery. The aim of this chapter is to provide a summary of what is currently known about AVP-mediated AQP2 trafficking, dissecting the roles of individual phosphorylation sites, kinases and phosphatases and interacting proteins. From this, the picture of an immensely complex process emerges, of which many structural and molecular details remains to be elucidated.
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14
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Holst MR, Nejsum LN. A versatile aquaporin-2 cell system for quantitative temporal expression and live cell imaging. Am J Physiol Renal Physiol 2019; 317:F124-F132. [PMID: 31091121 DOI: 10.1152/ajprenal.00150.2019] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Aquaporin-2 (AQP2) fine tunes urine concentration in response to the antidiuretic hormone vasopressin. In addition, AQP2 has been suggested to promote cell migration and epithelial morphogenesis. A cell system allowing temporal and quantitative control of expression levels of AQP2 and phospho-mimicking mutants has been missing, as has a system allowing expression of fluorescently tagged AQP2 for time-lapse imaging. In the present study, we generated and validated a Flp-In T-REx Madin-Darby canine kidney cell system for temporal and quantitative control of AQP2 and phospho-mimicking mutants. We verified that expression levels can be temporally and quantitatively controlled and that AQP2 translocated to the plasma membrane in response to elevated cAMP, which also induced S256 phosphorylation. The phospho-mimicking mutants AQP2-S256A and AQP2-S256D localized as previously described, primarily intracellular and to the plasma membrane, respectively. Induction of AQP2 expression in combination with transient, low expression of enhanced green fluorescent protein-tagged AQP2 enabled expression without aggregation and correct translocation in response to elevated cAMP. Interestingly, time-lapse imaging revealed AQP2-containing tubulating endosomes and that tubulation significantly decreased 30 min after cAMP elevation. This was mirrored by the phospho-mimicking mutants AQP2-S256A and AQP2-S256D, where AQP2-S256A-containing endosomes tubulated, whereas AQP2-S256D-containing endosomes did not. Thus, this cell system enables a multitude of cell-based assays warranted to provide deeper insights into the mechanisms of AQP2 regulation and effects on cell migration and epithelial morphogenesis.
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Affiliation(s)
- Mikkel R Holst
- Department of Clinical Medicine, Aarhus University , Aarhus , Denmark
| | - Lene N Nejsum
- Department of Clinical Medicine, Aarhus University , Aarhus , Denmark
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Michałek K, Grabowska M, Lepczyński A. Cellular localization and putative role of aquaporin-2 Ser-261 in the bovine kidney. JOURNAL OF ANIMAL AND FEED SCIENCES 2019. [DOI: 10.22358/jafs/103815/2019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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16
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The Expanding Role of Vesicles Containing Aquaporins. Cells 2018; 7:cells7100179. [PMID: 30360436 PMCID: PMC6210599 DOI: 10.3390/cells7100179] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Revised: 10/16/2018] [Accepted: 10/20/2018] [Indexed: 12/11/2022] Open
Abstract
In animals and plants, membrane vesicles containing proteins have been defined as key for biological systems involving different processes such as trafficking or intercellular communication. Docking and fusion of vesicles to the plasma membrane occur in living cells in response to different stimuli, such as environmental changes or hormones, and therefore play an important role in cell homeostasis as vehicles for certain proteins or other substances. Because aquaporins enhance the water permeability of membranes, their role as proteins immersed in vesicles formed of natural membranes is a recent topic of study. They regulate numerous physiological processes and could hence serve new biotechnological purposes. Thus, in this review, we have explored the physiological implications of the trafficking of aquaporins, the mechanisms that control their transit, and the proteins that coregulate the migration. In addition, the importance of exosomes containing aquaporins in the cell-to-cell communication processes in animals and plants have been analyzed, together with their potential uses in biomedicine or biotechnology. The properties of aquaporins make them suitable for use as biomarkers of different aquaporin-related diseases when they are included in exosomes. Finally, the fact that these proteins could be immersed in biomimetic membranes opens future perspectives for new biotechnological applications.
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Fotso Soh J, Torres-Platas SG, Beaulieu S, Mantere O, Platt R, Mucsi I, Saury S, Renaud S, Levinson A, Andreazza AC, Mulsant BH, Müller D, Schaffer A, Dols A, Cervantes P, Low NCP, Herrmann N, Christensen BM, Trepiccione F, Rajji T, Rej S. Atorvastatin in the treatment of Lithium-induced nephrogenic diabetes insipidus: the protocol of a randomized controlled trial. BMC Psychiatry 2018; 18:227. [PMID: 30012135 PMCID: PMC6048831 DOI: 10.1186/s12888-018-1793-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/21/2018] [Accepted: 06/14/2018] [Indexed: 01/17/2023] Open
Abstract
BACKGROUND Lithium is the gold-standard treatment for bipolar disorder, is highly effective in treating major depressive disorder, and has anti-suicidal properties. However, clinicians are increasingly avoiding lithium largely due to fears of renal toxicity. Nephrogenic Diabetes Insipidus (NDI) occurs in 15-20% of lithium users and predicts a 2-3 times increased risk of chronic kidney disease (CKD). We recently found that use of statins is associated with lower NDI risk in a cross-sectional study. In this current paper, we describe the methodology of a randomized controlled trial (RCT) to treat lithium-induced NDI using atorvastatin. METHODS We will conduct a 12-week, double-blind placebo-controlled RCT of atorvastatin for lithium-induced NDI at McGill University, Montreal, Canada. We will recruit 60 current lithium users, aged 18-85, who have indicators of NDI, which we defined as urine osmolality (UOsm) < 600 mOsm/kg after 10-h fluid restriction. We will randomize patients to atorvastatin (20 mg/day) or placebo for 12 weeks. We will examine whether this improves measures of NDI: UOsm and aquaporin (AQP2) excretion at 12-week follow-up, adjusted for baseline. RESULTS Not applicable. CONCLUSION The aim of this clinical trial is to provide preliminary data about the efficacy of atorvastatin in treating NDI. If successful, lithium could theoretically be used more safely in patients with a reduced subsequent risk of CKD, hypernatremia, and acute kidney injury (AKI). If future definitive trials confirm this, this could potentially allow more patients to benefit from lithium, while minimizing renal risk. TRIAL REGISTRATION ClinicalTrials.gov NCT02967653 . Registered in February 2017.
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Affiliation(s)
- Jocelyn Fotso Soh
- Geri-PARTy Research Group, Jewish General Hospital/Lady Davis Institute, McGill University, 4333 Cote Ste-Catherine, Montreal, QC, H3T, 1E4, Montreal, Canada.
| | - Susana G. Torres-Platas
- 0000 0004 1936 8649grid.14709.3bGeri-PARTy Research Group, Jewish General Hospital/Lady Davis Institute, McGill University, 4333 Cote Ste-Catherine, Montreal, QC, H3T, 1E4, Montreal, Canada
| | - Serge Beaulieu
- 0000 0004 1936 8649grid.14709.3bDouglas Mental Health University Institute and Department of Psychiatry, McGill University, Montreal, Canada
| | - Outi Mantere
- 0000 0004 1936 8649grid.14709.3bDouglas Mental Health University Institute and Department of Psychiatry, McGill University, Montreal, Canada
| | - Robert Platt
- 0000 0000 9064 4811grid.63984.30Department of Epidemiology, Biostatistics and Occupational Health, McGill University Health Centre, Montreal, Canada
| | - Istvan Mucsi
- 0000 0001 2157 2938grid.17063.33Division of Nephrology, University Health Network, University of Toronto (UofT), Toronto, Canada
| | - Sybille Saury
- 0000 0004 1936 8649grid.14709.3bDouglas Mental Health University Institute and Department of Psychiatry, McGill University, Montreal, Canada
| | - Suzane Renaud
- 0000 0004 1936 8649grid.14709.3bDouglas Mental Health University Institute and Department of Psychiatry, McGill University, Montreal, Canada
| | - Andrea Levinson
- 0000 0001 2157 2938grid.17063.33Department of Psychiatry, Centre for Addiction and Mental Health & Department of Psychiatry, University of Toronto, Toronto, Canada
| | - Ana C. Andreazza
- 0000 0001 2157 2938grid.17063.33Department of Psychiatry, Centre for Addiction and Mental Health & Department of Psychiatry, University of Toronto, Toronto, Canada
| | - Benoit H. Mulsant
- 0000 0001 2157 2938grid.17063.33Department of Psychiatry, Centre for Addiction and Mental Health & Department of Psychiatry, University of Toronto, Toronto, Canada
| | - Daniel Müller
- 0000 0001 2157 2938grid.17063.33Department of Psychiatry, Centre for Addiction and Mental Health & Department of Psychiatry, University of Toronto, Toronto, Canada
| | - Ayal Schaffer
- 0000 0001 2157 2938grid.17063.33Department of Psychiatry, Sunnybrook Research Institute, University of Toronto, Toronto, Canada
| | - Annemiek Dols
- Department of Psychiatry, GGZ, Geest, Amsterdam, the Netherlands
| | - Pablo Cervantes
- 0000 0000 9064 4811grid.63984.30Department of Psychiatry, McGill University Health Centre, Montreal, Canada
| | - Nancy CP Low
- 0000 0000 9064 4811grid.63984.30Department of Psychiatry, McGill University Health Centre, Montreal, Canada
| | - Nathan Herrmann
- 0000 0001 2157 2938grid.17063.33Department of Psychiatry, Sunnybrook Research Institute, University of Toronto, Toronto, Canada
| | - Birgitte M. Christensen
- 0000 0001 1956 2722grid.7048.bDepartment of Biomedicine, University of Aarhus, Aarhus, Denmark
| | - Francesco Trepiccione
- 0000 0001 0790 385Xgrid.4691.aDivision of Nephrology, University of Naples, Naples, Italy
| | - Tarek Rajji
- 0000 0001 2157 2938grid.17063.33Department of Psychiatry, Centre for Addiction and Mental Health & Department of Psychiatry, University of Toronto, Toronto, Canada
| | - Soham Rej
- 0000 0004 1936 8649grid.14709.3bGeri-PARTy Research Group, Jewish General Hospital/Lady Davis Institute, McGill University, 4333 Cote Ste-Catherine, Montreal, QC, H3T, 1E4, Montreal, Canada ,0000 0004 1936 8649grid.14709.3bDouglas Mental Health University Institute and Department of Psychiatry, McGill University, Montreal, Canada
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Umejiego EN, Wang Y, Knepper MA, Chou CL. Roflumilast and aquaporin-2 regulation in rat renal inner medullary collecting duct. Physiol Rep 2017; 5:5/2/e13121. [PMID: 28108651 PMCID: PMC5269416 DOI: 10.14814/phy2.13121] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Revised: 11/29/2016] [Accepted: 12/12/2016] [Indexed: 12/23/2022] Open
Abstract
Roflumilast is a cyclic nucleotide phosphodiesterase inhibitor that is FDA‐approved for treatment of chronic obstructive pulmonary disease. With a view toward possible use for treatment of patients with X‐linked nephrogenic diabetes insipidus (NDI) due to hemizygous mutations in the V2 vasopressin receptor, this study sought to determine the effect of roflumilast on aquaporin‐2 (AQP2) phosphorylation, AQP2 trafficking, and water permeability in the rat inner medullary collecting duct (IMCD). In the presence of the vasopressin analog dDAVP (0.1 nmol/L), both roflumilast and its active metabolite roflumilast N‐oxide (RNO) significantly increased phosphorylation at S256, S264, and S269, and decreased phosphorylation at S261 (immunoblotting) in IMCD suspensions in a dose‐dependent manner (3–3000 nmol/L). Another commonly used phosphodiesterase inhibitor, IBMX, affected phosphorylation only at the highest concentration in this range. However, neither roflumilast nor RNO had an effect on AQP2 phosphorylation in the absence of vasopressin. Furthermore, roflumilast alone did not increase AQP2 trafficking to the plasma membrane (immunofluorescence) or increase water permeability in freshly microdissected perfused IMCD segments. We conclude that roflumilast can be used to enhance vasopressin's action on AQP2 activity in the renal collecting duct, but has no detectable effect in the absence of vasopressin. These findings suggest that roflumilast may not have a beneficial effect in X‐linked NDI, but could find useful application in acquired NDI.
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Affiliation(s)
- Ezigbobiara N Umejiego
- Epithelial Systems Biology Laboratory, Systems Biology Center NHLBI National Institutes of Health, Bethesda, Maryland, 20892-1603
| | - Yanhua Wang
- Renal Division, Department of Medicine, Emory University, Atlanta, Georgia, 30322
| | - Mark A Knepper
- Epithelial Systems Biology Laboratory, Systems Biology Center NHLBI National Institutes of Health, Bethesda, Maryland, 20892-1603
| | - Chung-Lin Chou
- Epithelial Systems Biology Laboratory, Systems Biology Center NHLBI National Institutes of Health, Bethesda, Maryland, 20892-1603
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19
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Abstract
Diabetes insipidus is a disease characterized by polyuria and polydipsia due to inadequate release of arginine vasopressin from the posterior pituitary gland (neurohypophyseal diabetes insipidus) or due to arginine vasopressin insensitivity by the renal distal tubule, leading to a deficiency in tubular water reabsorption (nephrogenic diabetes insipidus). This article reviews the genetics of diabetes insipidus in the context of its diagnosis, clinical presentation, and therapy.
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Affiliation(s)
- Marie Helene Schernthaner-Reiter
- Clinical Division of Endocrinology and Metabolism, Department of Internal Medicine III, Medical University of Vienna, Waehringer Guertel 18-20, Vienna 1090, Austria; Section on Endocrinology and Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, 31 Center Drive, Bethesda, MD 20892, USA.
| | - Constantine A Stratakis
- Section on Endocrinology and Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, 31 Center Drive, Bethesda, MD 20892, USA
| | - Anton Luger
- Clinical Division of Endocrinology and Metabolism, Department of Internal Medicine III, Medical University of Vienna, Waehringer Guertel 18-20, Vienna 1090, Austria
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20
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Shimizu K, Sano M, Kita A, Sawai N, Iizuka-Kogo A, Kogo H, Aoki T, Takata K, Matsuzaki T. Phosphorylation and dephosphorylation of aquaporin-2 at serine 269 and its subcellular distribution during vasopressin-induced exocytosis and subsequent endocytosis in the rat kidney . ACTA ACUST UNITED AC 2017. [DOI: 10.1679/aohc.77.25] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | | | | | - Nobuhiko Sawai
- Present address: Department of Molecular Medicine and Anatomy, Nippon Medical School,
| | | | | | - Takeo Aoki
- Present address: School of Radiological Technology, Gunma Prefectural College of Health Sciences,
| | - Kuniaki Takata
- Present address: Gunma Prefectural College of Health Sciences,
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21
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Loop B serine of a plasma membrane aquaporin type PIP2 but not PIP1 plays a key role in pH sensing. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2016; 1858:2778-2787. [DOI: 10.1016/j.bbamem.2016.08.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Revised: 07/08/2016] [Accepted: 08/07/2016] [Indexed: 11/17/2022]
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22
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Arnspang EC, Login FH, Koffman JS, Sengupta P, Nejsum LN. AQP2 Plasma Membrane Diffusion Is Altered by the Degree of AQP2-S256 Phosphorylation. Int J Mol Sci 2016; 17:ijms17111804. [PMID: 27801846 PMCID: PMC5133805 DOI: 10.3390/ijms17111804] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Revised: 09/15/2016] [Accepted: 09/22/2016] [Indexed: 01/21/2023] Open
Abstract
Fine tuning of urine concentration occurs in the renal collecting duct in response to circulating levels of arginine vasopressin (AVP). AVP stimulates intracellular cAMP production, which mediates exocytosis of sub-apical vesicles containing the water channel aquaporin-2 (AQP2). Protein Kinase A (PKA) phosphorylates AQP2 on serine-256 (S256), which triggers plasma membrane accumulation of AQP2. This mediates insertion of AQP2 into the apical plasma membrane, increasing water permeability of the collecting duct. AQP2 is a homo-tetramer. When S256 on all four monomers is changed to the phosphomimic aspartic acid (S256D), AQP2-S256D localizes to the plasma membrane and internalization is decreased. In contrast, when S256 is mutated to alanine (S256A) to mimic non-phosphorylated AQP2, AQP2-S256A localizes to intracellular vesicles as well as the plasma membrane, with increased internalization from the plasma membrane. S256 phosphorylation is not necessary for exocytosis and dephosphorylation is not necessary for endocytosis, however, the degree of S256 phosphorylation is hypothesized to regulate the kinetics of AQP2 endocytosis and thus, retention time in the plasma membrane. Using k-space Image Correlation Spectroscopy (kICS), we determined how the number of phosphorylated to non-phosphorylated S256 monomers in the AQP2 tetramer affects diffusion speed of AQP2 in the plasma membrane. When all four monomers mimicked constitutive phosphorylation (AQP2-S256D), diffusion was faster than when all four were non-phosphorylated (AQP2-S256A). AQP2-WT diffused at a speed similar to that of AQP2-S256D. When an average of two or three monomers in the tetramer were constitutively phosphorylated, the average diffusion coefficients were not significantly different to that of AQP2-S256D. However, when only one monomer was phosphorylated, diffusion was slower and similar to AQP2-S256A. Thus, AQP2 with two to four phosphorylated monomers has faster plasma membrane kinetics, than the tetramer which contains just one or no phosphorylated monomers. This difference in diffusion rate may reflect behavior of AQP2 tetramers destined for either plasma membrane retention or endocytosis.
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Affiliation(s)
- Eva C Arnspang
- Department of Clinical Medicine, Aarhus University, DK-8000 Aarhus C, Denmark.
- The Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA.
| | - Frédéric H Login
- Department of Clinical Medicine, Aarhus University, DK-8000 Aarhus C, Denmark.
| | - Jennifer S Koffman
- Department of Interdisciplinary Nanoscience Center, Aarhus University, DK-8000 Aarhus C, Denmark.
| | - Prabuddha Sengupta
- The Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA.
| | - Lene N Nejsum
- Department of Clinical Medicine, Aarhus University, DK-8000 Aarhus C, Denmark.
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LeMaire SM, Raghuram V, Grady CR, Pickering CM, Chou CL, Umejiego EN, Knepper MA. Serine/threonine phosphatases and aquaporin-2 regulation in renal collecting duct. Am J Physiol Renal Physiol 2016; 312:F84-F95. [PMID: 27784696 DOI: 10.1152/ajprenal.00455.2016] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Revised: 10/05/2016] [Accepted: 10/19/2016] [Indexed: 11/22/2022] Open
Abstract
Phosphorylation of the aquaporin-2 (AQP2) water channel at four COOH-terminal serines plays a central role in the regulation of water permeability of the renal collecting duct. The level of phosphorylation at these sites is determined by a balance between phosphorylation by protein kinases and dephosphorylation by phosphatases. The phosphatases that dephosphorylate AQP2 have not been identified. Here, we use large-scale data integration techniques to identify serine-threonine phosphatases likely to interact with AQP2 in renal collecting duct principal cells. As a first step, we have created a comprehensive list of 38 S/T phosphatase catalytic subunits present in the mammalian genome. Then we used Bayes' theorem to integrate available information from large-scale data sets from proteomic and transcriptomic studies to rank the known S/T phosphatases with regard to the likelihood that they interact with AQP2 in renal collecting duct cells. To broaden the analysis, we have generated new proteomic data (LC-MS/MS) identifying 4538 distinct proteins including 22 S/T phosphatases in cytoplasmic fractions from native inner medullary collecting duct cells from rats. The official gene symbols corresponding to the top-ranked phosphatases (common names in parentheses) were: Ppp1cb (PP1-β), Ppm1g (PP2C), Ppp1ca (PP1-α), Ppp3ca (PP2-B or calcineurin), Ppp2ca (PP2A-α), Ppp1cc (PP1-γ), Ppp2cb (PP2A-β), Ppp6c (PP6C), and Ppp5c (PP5). This ranking correlates well with results of prior reductionist studies of ion and water channels in renal collecting duct cells.
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Affiliation(s)
- Sophia M LeMaire
- Epithelial Systems Biology Laboratory, Systems Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland; and.,Howard University College of Medicine, Washington, District of Columbia
| | - Viswanathan Raghuram
- Epithelial Systems Biology Laboratory, Systems Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland; and
| | - Cameron R Grady
- Epithelial Systems Biology Laboratory, Systems Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland; and
| | - Christina M Pickering
- Epithelial Systems Biology Laboratory, Systems Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland; and
| | - Chung-Lin Chou
- Epithelial Systems Biology Laboratory, Systems Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland; and
| | - Ezigbobiara N Umejiego
- Epithelial Systems Biology Laboratory, Systems Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland; and
| | - Mark A Knepper
- Epithelial Systems Biology Laboratory, Systems Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland; and
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Jung HJ, Kwon TH. Molecular mechanisms regulating aquaporin-2 in kidney collecting duct. Am J Physiol Renal Physiol 2016; 311:F1318-F1328. [PMID: 27760771 DOI: 10.1152/ajprenal.00485.2016] [Citation(s) in RCA: 82] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Revised: 10/11/2016] [Accepted: 10/11/2016] [Indexed: 01/04/2023] Open
Abstract
The kidney collecting duct is an important renal tubular segment for regulation of body water homeostasis and urine concentration. Water reabsorption in the collecting duct principal cells is controlled by vasopressin, a peptide hormone that induces the osmotic water transport across the collecting duct epithelia through regulation of water channel proteins aquaporin-2 (AQP2) and aquaporin-3 (AQP3). In particular, vasopressin induces both intracellular translocation of AQP2-bearing vesicles to the apical plasma membrane and transcription of the Aqp2 gene to increase AQP2 protein abundance. The signaling pathways, including AQP2 phosphorylation, RhoA phosphorylation, intracellular calcium mobilization, and actin depolymerization, play a key role in the translocation of AQP2. This review summarizes recent data demonstrating the regulation of AQP2 as the underlying molecular mechanism for the homeostasis of water balance in the body.
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Affiliation(s)
- Hyun Jun Jung
- Epithelial Systems Biology Laboratory, Systems Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland; and
| | - Tae-Hwan Kwon
- Department of Biochemistry and Cell Biology, School of Medicine, Kyungpook National University, Taegu, Korea
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25
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Cheung PW, Nomura N, Nair AV, Pathomthongtaweechai N, Ueberdiek L, Lu HAJ, Brown D, Bouley R. EGF Receptor Inhibition by Erlotinib Increases Aquaporin 2-Mediated Renal Water Reabsorption. J Am Soc Nephrol 2016; 27:3105-3116. [PMID: 27694161 PMCID: PMC5042667 DOI: 10.1681/asn.2015080903] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Accepted: 01/28/2016] [Indexed: 01/04/2023] Open
Abstract
Nephrogenic diabetes insipidus (NDI) is caused by impairment of vasopressin (VP) receptor type 2 signaling. Because potential therapies for NDI that target the canonical VP/cAMP/protein kinase A pathway have so far proven ineffective, alternative strategies for modulating aquaporin 2 (AQP2) trafficking have been sought. Successful identification of compounds by our high-throughput chemical screening assay prompted us to determine whether EGF receptor (EGFR) inhibitors stimulate AQP2 trafficking and reduce urine output. Erlotinib, a selective EGFR inhibitor, enhanced AQP2 apical membrane expression in collecting duct principal cells and reduced urine volume by 45% after 5 days of treatment in mice with lithium-induced NDI. Similar to VP, erlotinib increased exocytosis and decreased endocytosis in LLC-PK1 cells, resulting in a significant increase in AQP2 membrane accumulation. Erlotinib increased phosphorylation of AQP2 at Ser-256 and Ser-269 and decreased phosphorylation at Ser-261 in a dose-dependent manner. However, unlike VP, the effect of erlotinib was independent of cAMP, cGMP, and protein kinase A. Conversely, EGF reduced VP-induced AQP2 Ser-256 phosphorylation, suggesting crosstalk between VP and EGF in AQP2 trafficking and a role of EGF in water homeostasis. These results reveal a novel pathway that contributes to the regulation of AQP2-mediated water reabsorption and suggest new potential therapeutic strategies for NDI treatment.
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Affiliation(s)
- Pui W Cheung
- Center for Systems Biology, Program in Membrane Biology, Division of Nephrology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
| | - Naohiro Nomura
- Center for Systems Biology, Program in Membrane Biology, Division of Nephrology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
| | - Anil V Nair
- Center for Systems Biology, Program in Membrane Biology, Division of Nephrology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
| | - Nutthapoom Pathomthongtaweechai
- Center for Systems Biology, Program in Membrane Biology, Division of Nephrology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
| | - Lars Ueberdiek
- Center for Systems Biology, Program in Membrane Biology, Division of Nephrology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
| | - Hua A Jenny Lu
- Center for Systems Biology, Program in Membrane Biology, Division of Nephrology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
| | - Dennis Brown
- Center for Systems Biology, Program in Membrane Biology, Division of Nephrology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
| | - Richard Bouley
- Center for Systems Biology, Program in Membrane Biology, Division of Nephrology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
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Vukićević T, Schulz M, Faust D, Klussmann E. The Trafficking of the Water Channel Aquaporin-2 in Renal Principal Cells-a Potential Target for Pharmacological Intervention in Cardiovascular Diseases. Front Pharmacol 2016; 7:23. [PMID: 26903868 PMCID: PMC4749865 DOI: 10.3389/fphar.2016.00023] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Accepted: 01/25/2016] [Indexed: 01/13/2023] Open
Abstract
Arginine-vasopressin (AVP) stimulates the redistribution of water channels, aquaporin-2 (AQP2) from intracellular vesicles into the plasma membrane of renal collecting duct principal cells. By this AVP directs 10% of the water reabsorption from the 170 L of primary urine that the human kidneys produce each day. This review discusses molecular mechanisms underlying the AVP-induced redistribution of AQP2; in particular, it provides an overview over the proteins participating in the control of its localization. Defects preventing the insertion of AQP2 into the plasma membrane cause diabetes insipidus. The disease can be acquired or inherited, and is characterized by polyuria and polydipsia. Vice versa, up-regulation of the system causing a predominant localization of AQP2 in the plasma membrane leads to excessive water retention and hyponatremia as in the syndrome of inappropriate antidiuretic hormone secretion (SIADH), late stage heart failure or liver cirrhosis. This article briefly summarizes the currently available pharmacotherapies for the treatment of such water balance disorders, and discusses the value of newly identified mechanisms controlling AQP2 for developing novel pharmacological strategies. Innovative concepts for the therapy of water balance disorders are required as there is a medical need due to the lack of causal treatments.
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Affiliation(s)
- Tanja Vukićević
- Max Delbrück Center for Molecular Medicine (MDC) in the Helmholtz Association Berlin, Germany
| | - Maike Schulz
- Max Delbrück Center for Molecular Medicine (MDC) in the Helmholtz Association Berlin, Germany
| | - Dörte Faust
- Max Delbrück Center for Molecular Medicine (MDC) in the Helmholtz Association Berlin, Germany
| | - Enno Klussmann
- Max Delbrück Center for Molecular Medicine (MDC) in the Helmholtz AssociationBerlin, Germany; German Centre for Cardiovascular ResearchBerlin, Germany
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Dollerup P, Thomsen TM, Nejsum LN, Færch M, Österbrand M, Gregersen N, Rittig S, Christensen JH, Corydon TJ. Partial nephrogenic diabetes insipidus caused by a novel AQP2 variation impairing trafficking of the aquaporin-2 water channel. BMC Nephrol 2015; 16:217. [PMID: 26714855 PMCID: PMC4696136 DOI: 10.1186/s12882-015-0213-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Accepted: 12/21/2015] [Indexed: 01/16/2023] Open
Abstract
BACKGROUND Autosomal dominant inheritance of congenital nephrogenic diabetes insipidus (CNDI) is rare and usually caused by variations in the AQP2 gene. We have investigated the genetic and molecular background underlying symptoms of diabetes insipidus (DI) in a Swedish family with autosomal dominant inheritance of the condition. METHODS The proband and her father were subjected to water deprivation testing and direct DNA sequencing of the coding regions of the AQP2 and AVP genes. Madin-Darby canine kidney (MDCK) cells stably expressing AQP2 variant proteins were generated by lentiviral gene delivery. Localization of AQP2 variant proteins in the cells under stimulated and unstimulated conditions was analyzed by means of immunostaining and confocal laser scanning microscopy. Intracellular trafficking of AQP2 variant proteins was studied using transient expression of mutant dynamin2-K44A-GFP protein and AQP2 variant protein phosphorylation levels were assessed by Western blotting analysis. RESULTS Clinical and genetic data suggest that the proband and her father suffer from partial nephrogenic DI due to a variation (g.4807C > T) in the AQP2 gene. The variation results in substitution of arginine-254 to tryptophan (p.R254W) in AQP2. Analysis of MDCK cells stably expressing AQP2 variant proteins revealed disabled phosphorylation, impaired trafficking and intracellular accumulation of AQP2-R254W protein. Notably, blocking of the endocytic pathway demonstrated impairment of AQP2-R254W to reach the cell surface. CONCLUSIONS Partial CNDI in the Swedish family is caused by an AQP2 variation that seems to disable the encoded AQP2-R254W protein to reach the subapical vesicle population as well as impairing its phosphorylation at S256. The AQP2-R254W protein is thus unable to reach the plasma membrane to facilitate AVP mediated urine concentration.
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Affiliation(s)
- Pia Dollerup
- Department of Biomedicine, Aarhus University, Wilhelm Meyers Allé 4, 8000, Aarhus, Denmark.
| | - Troels Møller Thomsen
- Department of Biomedicine, Aarhus University, Wilhelm Meyers Allé 4, 8000, Aarhus, Denmark.
| | - Lene N Nejsum
- Department of Molecular Biology and Genetics and iNANO, Aarhus University, Aarhus, Denmark.
| | - Mia Færch
- Department of Pediatrics, Aarhus University Hospital, Aarhus, Denmark.
| | - Martin Österbrand
- Department of Pediatrics, Queen Silvia Children's Hospital, Gothenburg, Sweden.
| | - Niels Gregersen
- Research Unit for Molecular Medicine, Department of Clinical Medicine, Aarhus University Hospital, Aarhus, Denmark.
| | - Søren Rittig
- Department of Pediatrics, Aarhus University Hospital, Aarhus, Denmark.
| | - Jane H Christensen
- Department of Biomedicine, Aarhus University, Wilhelm Meyers Allé 4, 8000, Aarhus, Denmark.
| | - Thomas J Corydon
- Department of Biomedicine, Aarhus University, Wilhelm Meyers Allé 4, 8000, Aarhus, Denmark.
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Ren H, Yang B, Molina PA, Sands JM, Klein JD. NSAIDs Alter Phosphorylated Forms of AQP2 in the Inner Medullary Tip. PLoS One 2015; 10:e0141714. [PMID: 26517129 PMCID: PMC4627840 DOI: 10.1371/journal.pone.0141714] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Accepted: 10/12/2015] [Indexed: 11/18/2022] Open
Abstract
Vasopressin increases urine concentration through activation of aquaporin-2 (AQP2) in the collecting duct. Nonsteroidal anti-inflammatory drugs (NSAIDs) block prostaglandin E2 synthesis, and may suppress AQP2 producing a urine concentrating defect. There are four serines in AQP2 that are phosphorylated by vasopressin. To determine if chronic use of NSAIDs changes AQP2's phosphorylation at any of these residues, the effects of a non-selective NSAID, ibuprofen, and a COX-2-selective NSAID, meloxicam, were investigated. Daily ibuprofen or meloxicam increased the urine output and decreased the urine osmolality significantly by days 7 through 14. Concomitantly, meloxicam significantly reduced total AQP2 protein abundance in inner medulla (IM) tip to 64% of control and base to 63%, respectively. Ibuprofen significantly decreased total AQP2 in IM tip to 70% of control, with no change in base. Meloxicam significantly increased the ratios of p256-AQP2 and p261-AQP2 to total AQP2 in IM tip (to 44% and 40%, respectively). Ibuprofen increased the ratio of p256-AQP2 to total AQP2 in IM tip but did not affect p261-AQP2/total AQP2 in tip or base. Both ibuprofen and meloxicam increased p264-AQP2 and p269-AQP2 ratios in both tip and base. Ibuprofen increased UT-A1 levels in IM tip, but not in base. We conclude that NSAIDs reduce AQP2 abundance, contributing to decreased urine concentrating ability. They also increase some phosphorylated forms of AQP2. These changes may partially compensate for the decrease in AQP2 abundance, thereby lessening the decrease in urine osmolality.
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Affiliation(s)
- Huiwen Ren
- Department of Medicine, Renal Division, Emory University School of Medicine, Atlanta, Georgia, United States of America
- Department of Pharmacology, School of Basic Medical Sciences, Peking University, Beijing, China
| | - Baoxue Yang
- Department of Pharmacology, School of Basic Medical Sciences, Peking University, Beijing, China
| | - Patrick A. Molina
- Department of Medicine, Renal Division, Emory University School of Medicine, Atlanta, Georgia, United States of America
| | - Jeff M. Sands
- Department of Medicine, Renal Division, Emory University School of Medicine, Atlanta, Georgia, United States of America
- Department of Physiology, Emory University, Atlanta, Georgia, United States of America
| | - Janet D. Klein
- Department of Medicine, Renal Division, Emory University School of Medicine, Atlanta, Georgia, United States of America
- Department of Physiology, Emory University, Atlanta, Georgia, United States of America
- * E-mail:
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Klein N, Kümmerer N, Hobernik D, Schneider D. The AQP2 mutation V71M causes nephrogenic diabetes insipidus in humans but does not impair the function of a bacterial homolog. FEBS Open Bio 2015; 5:640-6. [PMID: 26442203 PMCID: PMC4552806 DOI: 10.1016/j.fob.2015.07.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Revised: 06/30/2015] [Accepted: 07/21/2015] [Indexed: 01/26/2023] Open
Abstract
The aquaporin 2 mutation V71M causes nephrogenic diabetes insipidus in humans. Val71 is highly conserved in aqua(glycero)porins and points into the translocation pore. The V71M mutation does not impair the activity and oligomerization of a bacterial homolog.
Several point mutations have been identified in human aquaporins, but their effects on the function of the respective aquaporins are mostly enigmatic. We analyzed the impact of the aquaporin 2 mutation V71M, which causes nephrogenic diabetes insipidus in humans, on aquaporin structure and activity, using the bacterial aquaglyceroporin GlpF as a model. Importantly, the sequence and structure around the V71M mutation is highly conserved between aquaporin 2 and GlpF. The V71M mutation neither impairs substrate flux nor oligomerization of the aquaglyceroporin. Therefore, the human aquaporin 2 mutant V71M is most likely active, but cellular trafficking is probably impaired.
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Key Words
- AQP ER, endoplasmic reticulum
- AQP, aquaporin
- AVP, arginine vasopressin
- AVPR2, V2 receptor
- Activity
- Aquaporin
- GlpF
- GlpF, glycerol facilitator
- GpA, glycophorin A
- HM, half-membrane-spanning
- NDI, nephrogenic diabetes insipidus
- Nephrogenic diabetes insipidus
- Protein oligomerization
- TM, transmembrane
- wt, wild-type
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Affiliation(s)
- Noreen Klein
- Institut für Pharmazie und Biochemie, Johannes Gutenberg-Universität Mainz, 55128 Mainz, Germany
| | - Nadine Kümmerer
- Institut für Pharmazie und Biochemie, Johannes Gutenberg-Universität Mainz, 55128 Mainz, Germany
| | - Dominika Hobernik
- Institut für Pharmazie und Biochemie, Johannes Gutenberg-Universität Mainz, 55128 Mainz, Germany
| | - Dirk Schneider
- Institut für Pharmazie und Biochemie, Johannes Gutenberg-Universität Mainz, 55128 Mainz, Germany
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Bockenhauer D, Bichet DG. Pathophysiology, diagnosis and management of nephrogenic diabetes insipidus. Nat Rev Nephrol 2015; 11:576-88. [PMID: 26077742 DOI: 10.1038/nrneph.2015.89] [Citation(s) in RCA: 162] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Healthy kidneys maintain fluid and electrolyte homoeostasis by adjusting urine volume and composition according to physiological needs. The final urine composition is determined in the last tubular segment: the collecting duct. Water permeability in the collecting duct is regulated by arginine vasopressin (AVP). Secretion of AVP from the neurohypophysis is regulated by a complex signalling network that involves osmosensors, barosensors and volume sensors. AVP facilitates aquaporin (AQP)-mediated water reabsorption via activation of the vasopressin V2 receptor (AVPR2) in the collecting duct, thus enabling concentration of urine. In nephrogenic diabetes insipidus (NDI), inability of the kidneys to respond to AVP results in functional AQP deficiency. Consequently, affected patients have constant diuresis, resulting in large volumes of dilute urine. Primary forms of NDI result from mutations in the genes that encode the key proteins AVPR2 and AQP2, whereas secondary forms are associated with biochemical abnormalities, obstructive uropathy or the use of certain medications, particularly lithium. Treatment of the disease is informed by identification of the underlying cause. Here we review the clinical aspects and diagnosis of NDI, the various aetiologies, current treatment options and potential future developments.
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Affiliation(s)
- Detlef Bockenhauer
- University College London Institute of Child Health, 30 Guilford Street, London WC1N 1EH, UK
| | - Daniel G Bichet
- Departments of Medicine and Molecular and Integrative Physiology, Université de Montréal Research Center, Hôpital du Sacré-Coeur de Montréal, 5400 Boulevard Gouin Ouest, Montréal, QC H4J 1C5 Canada
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AVP-induced increase in AQP2 and p-AQP2 is blunted in heart failure during cardiac remodeling and is associated with decreased AT1R abundance in rat kidney. PLoS One 2015; 10:e0116501. [PMID: 25658446 PMCID: PMC4319737 DOI: 10.1371/journal.pone.0116501] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Accepted: 12/10/2014] [Indexed: 01/02/2023] Open
Abstract
AIM The objective was to examine the renal effects of long-term increased angiotensin II and vasopressin plasma levels in early-stage heart failure (HF). We investigated the regulations of the V2 vasopressin receptor, the type 1A angiotensin II receptor, the (pro)renin receptor, and the water channels AQP2, AQP1, AQP3, and AQP4 in the inner medulla of rat kidney. METHODS HF was induced by coronary artery ligation. Sixty-eight rats were allocated to six groups: Sham (N = 11), HF (N = 11), sodium restricted sham (N = 11), sodium restricted HF (N = 11), sodium restricted sham + DDAVP (N = 12), and sodium restricted HF + DDAVP (N = 12). 1-desamino-8-D-arginine vasopressin (0.5 ng h-1 for 7 days) or vehicle was administered. Pre- and post-treatment echocardiographic evaluation was performed. The rats were sacrificed at day 17 after surgery, before cardiac remodeling in rat is known to be completed. RESULTS HF rats on standard sodium diet and sodium restriction displayed biochemical markers of HF. These rats developed hyponatremia, hypo-osmolality, and decreased fractional excretion of sodium. Increase of AQP2 and p(Ser256)-AQP2 abundance in all HF groups was blunted compared with control groups even when infused with DDAVP and despite increased vasopressin V2 receptor and Gsα abundance. This was associated with decreased protein abundance of the AT1A receptor in HF groups vs. controls. CONCLUSION Early-stage HF is associated with blunted increase in AQP2 and p(Ser256)-AQP2 despite of hyponatremia, hypo-osmolality, and increased inner medullary vasopressin V2 receptor expression. Decreased type 1A angiotensin II receptor abundance likely plays a role in the transduction of these effects.
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Moeller HB, Aroankins TS, Slengerik-Hansen J, Pisitkun T, Fenton RA. Phosphorylation and ubiquitylation are opposing processes that regulate endocytosis of the water channel aquaporin-2. J Cell Sci 2014; 127:3174-83. [PMID: 24876223 DOI: 10.1242/jcs.150680] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The post-translational modifications (PTMs) phosphorylation and ubiquitylation regulate plasma membrane protein function. Here, we examine the interplay between phosphorylation and ubiquitylation of the membrane protein aquaporin-2 (AQP2) and demonstrate that phosphorylation can override the previously suggested dominant endocytic signal of K63-linked polyubiquitylation. In polarized epithelial cells, although S256 is an important phosphorylation site for AQP2 membrane localization, the rate of AQP2 endocytosis was reduced by prolonging phosphorylation specifically at S269. Despite their close proximity, AQP2 phosphorylation at S269 and ubiquitylation at K270 can occur in parallel, with increased S269 phosphorylation and decreased AQP2 endocytosis occurring when K270 polyubiquitylation levels are maximal. In vivo studies support this data, with maximal levels of AQP2 ubiquitylation occurring in parallel to maximal S269 phosphorylation and enhanced AQP2 plasma membrane localization. In conclusion, we demonstrate for the first time that although K63-linked polyubiquitylation marks AQP2 for endocytosis, site-specific phosphorylation can counteract polyubiquitylation to determine its final localization. Similar mechanisms might exist for other plasma membrane proteins.
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Affiliation(s)
- Hanne B Moeller
- Department of Biomedicine, Center for Interactions of Proteins in Epithelial Transport (InterPrET), Aarhus University, Aarhus DK-8000, Denmark
| | - Takwa Shaiman Aroankins
- Department of Biomedicine, Center for Interactions of Proteins in Epithelial Transport (InterPrET), Aarhus University, Aarhus DK-8000, Denmark
| | - Joachim Slengerik-Hansen
- Department of Biomedicine, Center for Interactions of Proteins in Epithelial Transport (InterPrET), Aarhus University, Aarhus DK-8000, Denmark
| | - Trairak Pisitkun
- Department of Biomedicine, Center for Interactions of Proteins in Epithelial Transport (InterPrET), Aarhus University, Aarhus DK-8000, Denmark Faculty of Medicine, Chulalongkorn University, Bangkok 10330, Thailand
| | - Robert A Fenton
- Department of Biomedicine, Center for Interactions of Proteins in Epithelial Transport (InterPrET), Aarhus University, Aarhus DK-8000, Denmark
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Insights into structural mechanisms of gating induced regulation of aquaporins. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2014; 114:69-79. [DOI: 10.1016/j.pbiomolbio.2014.01.002] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2014] [Revised: 01/21/2014] [Accepted: 01/26/2014] [Indexed: 11/19/2022]
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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: 97] [Impact Index Per Article: 8.8] [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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Dynamic regulation and dysregulation of the water channel aquaporin-2: a common cause of and promising therapeutic target for water balance disorders. Clin Exp Nephrol 2013; 18:558-70. [DOI: 10.1007/s10157-013-0878-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2013] [Accepted: 09/24/2013] [Indexed: 12/11/2022]
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Nishimura H, Yang Y. Aquaporins in avian kidneys: function and perspectives. Am J Physiol Regul Integr Comp Physiol 2013; 305:R1201-14. [PMID: 24068044 DOI: 10.1152/ajpregu.00177.2013] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
For terrestrial vertebrates, water economy is a prerequisite for survival, and the kidney is their major osmoregulatory organ. Birds are the only vertebrates other than mammals that can concentrate urine in adaptation to terrestrial environments. Aquaporin (AQP) and glyceroporin (GLP) are phylogenetically old molecules and have been found in plants, microbial organisms, invertebrates, and vertebrates. Currently, 13 AQPs/aquaGLPs and isoforms are known to be present in mammals. AQPs 1, 2, 3, 4, 6, 7, 8, and 11 are expressed in the kidney; of these, AQPs 1, 2, 3, 4, and 7 are shown to be involved in fluid homeostasis. In avian kidneys, AQPs 1, 2, 3, and 4 have been identified and characterized. Also, gene and/or amino acid sequences of AQP5, AQP7, AQP8, AQP9, AQP11, and AQP12 have been reported in birds. AQPs 2 and 3 are expressed along cortical and medullary collecting ducts (CDs) and are responsible, respectively, for the water inflow and outflow of CD epithelial cells. While AQP4 plays an important role in water exit in the CD of mammalian kidneys, it is unlikely to participate in water outflow in avian CDs. This review summarizes current knowledge on structure and function of avian AQPs and compares them to those in mammalian and nonmammalian vertebrates. Also, we aim to provide input into, and perspectives on, the role of renal AQPs in body water homeostasis during ontogenic and phylogenetic advancement.
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Affiliation(s)
- Hiroko Nishimura
- Department of Physiology, University of Tennessee Health Science Center, Memphis, Tennessee
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Sasaki S, Yui N, Noda Y. Actin directly interacts with different membrane channel proteins and influences channel activities: AQP2 as a model. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2013; 1838:514-20. [PMID: 23770358 DOI: 10.1016/j.bbamem.2013.06.004] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Revised: 06/01/2013] [Accepted: 06/06/2013] [Indexed: 11/26/2022]
Abstract
The interplay between actin and 10 membrane channel proteins that have been shown to directly bind to actin are reviewed. The 10 membrane channel proteins covered in this review are aquaporin 2 (AQP2), cystic fibrosis transmembrane conductance regulator (CFTR), ClC2, short form of ClC3 (sClC3), chloride intracellular channel 1 (CLIC1), chloride intracellular channel 5 (CLIC5), epithelial sodium channel (ENaC), large-conductance calcium-activated potassium channel (Maxi-K), transient receptor potential vanilloid 4 (TRPV4), and voltage-dependent anion channel (VDAC), with particular attention to AQP2. In regard to AQP2, most reciprocal interactions between actin and AQP2 occur during intracellular trafficking, which are largely mediated through indirect binding. Actin and the actin cytoskeleton work as cables, barriers, stabilizers, and force generators for motility. However, as with ENaC, the effects of actin cytoskeleton on channel gating should be investigated further. This article is part of a Special Issue entitled: Reciprocal influences between cell cytoskeleton and membrane channels, receptors and transporters. Guest Editor: Jean Claude Hervé.
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Affiliation(s)
- Sei Sasaki
- Department of Nephrology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo 113-8519, Japan.
| | - Naofumi Yui
- Department of Nephrology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo 113-8519, Japan
| | - Yumi Noda
- Department of Nephrology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo 113-8519, Japan
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Moeller HB, Rittig S, Fenton RA. Nephrogenic diabetes insipidus: essential insights into the molecular background and potential therapies for treatment. Endocr Rev 2013; 34:278-301. [PMID: 23360744 PMCID: PMC3610677 DOI: 10.1210/er.2012-1044] [Citation(s) in RCA: 143] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The water channel aquaporin-2 (AQP2), expressed in the kidney collecting ducts, plays a pivotal role in maintaining body water balance. The channel is regulated by the peptide hormone arginine vasopressin (AVP), which exerts its effects through the type 2 vasopressin receptor (AVPR2). Disrupted function or regulation of AQP2 or the AVPR2 results in nephrogenic diabetes insipidus (NDI), a common clinical condition of renal origin characterized by polydipsia and polyuria. Over several years, major research efforts have advanced our understanding of NDI at the genetic, cellular, molecular, and biological levels. NDI is commonly characterized as hereditary (congenital) NDI, arising from genetic mutations in the AVPR2 or AQP2; or acquired NDI, due to for exmple medical treatment or electrolyte disturbances. In this article, we provide a comprehensive overview of the genetic, cell biological, and pathophysiological causes of NDI, with emphasis on the congenital forms and the acquired forms arising from lithium and other drug therapies, acute and chronic renal failure, and disturbed levels of calcium and potassium. Additionally, we provide an overview of the exciting new treatment strategies that have been recently proposed for alleviating the symptoms of some forms of the disease and for bypassing G protein-coupled receptor signaling.
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Affiliation(s)
- Hanne B Moeller
- Department of Biomedicine, Aarhus University, and Department of Pediatrics, Aarhus University Hospital, Wilhelm Meyers Alle 3, Building 1234, Aarhus 8000, Denmark.
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Wu H, Chen L, Zhang X, Zhou Q, Li JM, Berger S, Borok Z, Zhou B, Xiao Z, Yin H, Liu M, Wang Y, Jin J, Blackburn MR, Xia Y, Zhang W. Aqp5 is a new transcriptional target of Dot1a and a regulator of Aqp2. PLoS One 2013; 8:e53342. [PMID: 23326416 PMCID: PMC3542343 DOI: 10.1371/journal.pone.0053342] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2012] [Accepted: 11/27/2012] [Indexed: 12/02/2022] Open
Abstract
Dot1l encodes histone H3 K79 methyltransferase Dot1a. Mice with Dot1l deficiency in renal Aqp2-expressing cells (Dot1l(AC)) develop polyuria by unknown mechanisms. Here, we report that Aqp5 links Dot1l deletion to polyuria through Aqp2. cDNA array analysis revealed and real-time RT-qPCR validated Aqp5 as the most upregulated gene in Dot1l(AC) vs. control mice. Aqp5 protein is barely detectable in controls, but robustly expressed in the Dot1l(AC) kidneys, where it colocalizes with Aqp2. The upregulation of Aqp5 is coupled with reduced association of Dot1a and H3 dimethyl K79 with specific subregions in Aqp5 5' flanking region in Dot1l(AC) vs. control mice. In vitro studies in IMCD3, MLE-15 and 293Tcells using multiple approaches including real-time RT-qPCR, luciferase reporter assay, cell surface biotinylation assay, colocalization, and co-immunoprecipitation uncovered that Dot1a represses Aqp5. Human AQP5 interacts with AQP2 and impairs its cell surface localization. The AQP5/AQP2 complex partially resides in the ER/Golgi. Consistently, AQP5 is expressed in none of 15 normal controls, but in all of 17 kidney biopsies from patients with diabetic nephropathy. In the patients with diabetic nephropathy, AQP5 colocalizes with AQP2 in the perinuclear region and AQP5 expression is associated with impaired cellular H3 dimethyl K79. Taken together, these data for the first time identify Aqp5 as a Dot1a potential transcriptional target, and an Aqp2 binding partner and regulator, and suggest that the upregulated Aqp5 may contribute to polyuria, possibly by impairing Aqp2 membrane localization, in Dot1l(AC) mice and in patients with diabetic nephropathy.
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Affiliation(s)
- Hongyu Wu
- Department of Internal Medicine, The University of Texas Health Science Center at Houston, Houston, Texas, United States of America
| | - Lihe Chen
- Graduate School of Biomedical Sciences, The University of Texas Health Science Center at Houston, Houston, Texas, United States of America
| | - Xi Zhang
- Department of Internal Medicine, The University of Texas Health Science Center at Houston, Houston, Texas, United States of America
| | - Qiaoling Zhou
- Department of Internal Medicine, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Ju-Mei Li
- Department of Biochemistry and Molecular Biology, The University of Texas Health Science Center at Houston, Houston, Texas, United States of America
| | - Stefan Berger
- German Cancer Research Center, Division Molecular Biology of the Cell I, Heidelberg, Germany
| | - Zea Borok
- Will Rogers Institute Pulmonary Research Center, Division of Pulmonary and Critical Care Medicine, Department of Medicine, University of Southern California, Los Angeles, California, United States of America
| | - Beiyun Zhou
- Will Rogers Institute Pulmonary Research Center, Division of Pulmonary and Critical Care Medicine, Department of Medicine, University of Southern California, Los Angeles, California, United States of America
| | - Zhou Xiao
- Department of Internal Medicine, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Hongling Yin
- Department of Internal Medicine, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Mingyao Liu
- Graduate School of Biomedical Sciences, The University of Texas Health Science Center at Houston, Houston, Texas, United States of America
- Institute of Biosciences and Technology and Department of Molecular and Cellular Medicine, Texas A&M University System Health Science Center, Houston, Texas, United States of America
| | - Ying Wang
- Institute of Biosciences and Technology and Department of Molecular and Cellular Medicine, Texas A&M University System Health Science Center, Houston, Texas, United States of America
| | - Jianping Jin
- Graduate School of Biomedical Sciences, The University of Texas Health Science Center at Houston, Houston, Texas, United States of America
- Department of Biochemistry and Molecular Biology, The University of Texas Health Science Center at Houston, Houston, Texas, United States of America
| | - Michael R. Blackburn
- Graduate School of Biomedical Sciences, The University of Texas Health Science Center at Houston, Houston, Texas, United States of America
- Department of Biochemistry and Molecular Biology, The University of Texas Health Science Center at Houston, Houston, Texas, United States of America
| | - Yang Xia
- Graduate School of Biomedical Sciences, The University of Texas Health Science Center at Houston, Houston, Texas, United States of America
- Department of Biochemistry and Molecular Biology, The University of Texas Health Science Center at Houston, Houston, Texas, United States of America
| | - Wenzheng Zhang
- Department of Internal Medicine, The University of Texas Health Science Center at Houston, Houston, Texas, United States of America
- Graduate School of Biomedical Sciences, The University of Texas Health Science Center at Houston, Houston, Texas, United States of America
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41
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Congenital nephrogenic diabetes insipidus: the current state of affairs. Pediatr Nephrol 2012; 27:2183-204. [PMID: 22427315 DOI: 10.1007/s00467-012-2118-8] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2011] [Revised: 01/14/2012] [Accepted: 01/17/2012] [Indexed: 01/02/2023]
Abstract
The anti-diuretic hormone arginine vasopressin (AVP) is released from the pituitary upon hypovolemia or hypernatremia, and regulates water reabsorption in the renal collecting duct principal cells. Binding of AVP to the arginine vasopressin receptor type 2 (AVPR2) in the basolateral membrane leads to translocation of aquaporin 2 (AQP2) water channels to the apical membrane of the collecting duct principal cells, inducing water permeability of the membrane. This results in water reabsorption from the pro-urine into the medullary interstitium following an osmotic gradient. Congenital nephrogenic diabetes insipidus (NDI) is a disorder associated with mutations in either the AVPR2 or AQP2 gene, causing the inability of patients to concentrate their pro-urine, which leads to a high risk of dehydration. This review focuses on the current knowledge regarding the cell biological aspects of congenital X-linked, autosomal-recessive and autosomal-dominant NDI while specifically addressing the latest developments in the field. Based on deepened mechanistic understanding, new therapeutic strategies are currently being explored, which we also discuss here.
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42
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Sasaki S. Aquaporin 2: From its discovery to molecular structure and medical implications. Mol Aspects Med 2012; 33:535-46. [DOI: 10.1016/j.mam.2012.03.004] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2012] [Revised: 03/12/2012] [Accepted: 03/29/2012] [Indexed: 10/28/2022]
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Vasopressin increases S261 phosphorylation in AQP2-P262L, a mutant in recessive nephrogenic diabetes insipidus. Nephrol Dial Transplant 2012; 27:4389-97. [DOI: 10.1093/ndt/gfs292] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
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44
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Cell biology of vasopressin-regulated aquaporin-2 trafficking. Pflugers Arch 2012; 464:133-44. [DOI: 10.1007/s00424-012-1129-4] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2012] [Revised: 06/10/2012] [Accepted: 06/11/2012] [Indexed: 01/03/2023]
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Tamma G, Procino G, Svelto M, Valenti G. Cell culture models and animal models for studying the patho-physiological role of renal aquaporins. Cell Mol Life Sci 2012; 69:1931-46. [PMID: 22189994 PMCID: PMC11114724 DOI: 10.1007/s00018-011-0903-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2011] [Revised: 11/07/2011] [Accepted: 11/29/2011] [Indexed: 12/29/2022]
Abstract
Aquaporins (AQPs) are key players regulating urinary-concentrating ability. To date, eight aquaporins have been characterized and localized along the nephron, namely, AQP1 located in the proximal tubule, thin descending limb of Henle, and vasa recta; AQP2, AQP3 and AQP4 in collecting duct principal cells; AQP5 in intercalated cell type B; AQP6 in intercalated cells type A in the papilla; AQP7, AQP8 and AQP11 in the proximal tubule. AQP2, whose expression and cellular distribution is dependent on vasopressin stimulation, is involved in hereditary and acquired diseases affecting urine-concentrating mechanisms. Due to the lack of selective aquaporin inhibitors, the patho-physiological role of renal aquaporins has not yet been completely clarified, and despite extensive studies, several questions remain unanswered. Until the recent and large-scale development of genetic manipulation technology, which has led to the generation of transgenic mice models, our knowledge on renal aquaporin regulation was mainly based on in vitro studies with suitable renal cell models. Transgenic and knockout technology approaches are providing pivotal information on the role of aquaporins in health and disease. The main goal of this review is to update and summarize what we can learn from cell and animal models that will shed more light on our understanding of aquaporin-dependent renal water regulation.
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Affiliation(s)
- G Tamma
- Department of Biosciences, Biotechnologies and Pharmacological Sciences, University of Bari, Italy
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46
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Abstract
The central goal of this overview article is to summarize recent findings in renal epithelial transport,focusing chiefly on the connecting tubule (CNT) and the cortical collecting duct (CCD).Mammalian CCD and CNT are involved in fine-tuning of electrolyte and fluid balance through reabsorption and secretion. Specific transporters and channels mediate vectorial movements of water and solutes in these segments. Although only a small percent of the glomerular filtrate reaches the CNT and CCD, these segments are critical for water and electrolyte homeostasis since several hormones, for example, aldosterone and arginine vasopressin, exert their main effects in these nephron sites. Importantly, hormones regulate the function of the entire nephron and kidney by affecting channels and transporters in the CNT and CCD. Knowledge about the physiological and pathophysiological regulation of transport in the CNT and CCD and particular roles of specific channels/transporters has increased tremendously over the last two decades.Recent studies shed new light on several key questions concerning the regulation of renal transport.Precise distribution patterns of transport proteins in the CCD and CNT will be reviewed, and their physiological roles and mechanisms mediating ion transport in these segments will also be covered. Special emphasis will be given to pathophysiological conditions appearing as a result of abnormalities in renal transport in the CNT and CCD.
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Affiliation(s)
- Alexander Staruschenko
- Department of Physiology and Kidney Disease Center, Medical College of Wisconsin, Milwaukee, Wisconsin, USA.
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47
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Abstract
Targeted positioning of the water channel AQP2 (aquaporin-2) strictly regulates body water homoeostasis. Trafficking of AQP2 to the apical membrane is critical for the reabsorption of water in renal collecting ducts. In addition to the cAMP-mediated effect of vasopressin on AQP2 trafficking to the apical membrane, other signalling cascades can also induce this sorting. Recently, AQP2-binding proteins which could regulate this trafficking have been discovered; SPA-1 (signal-induced proliferation-associated gene-1), a GAP (GTPase-activating protein) for Rap1, and the cytoskeletal protein actin. This review summarizes recent advances related to the trafficking mechanisms of AQP2.
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Affiliation(s)
- Yumi Noda
- Department of Nephrology, Tokyo Medical and Dental University, Tokyo 113-8519, Japan
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48
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Hoffert JD, Pisitkun T, Knepper MA. Phosphoproteomics of vasopressin signaling in the kidney. Expert Rev Proteomics 2011; 8:157-63. [PMID: 21501009 DOI: 10.1586/epr.11.14] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Protein phosphorylation plays a critical role in the signaling pathways regulating water and solute transport in the distal renal tubule (i.e., renal collecting duct). A central mediator in this process is the antidiuretic peptide hormone arginine vasopressin, which regulates a number of transport proteins including water channel aquaporin-2 and urea transporters (UT-A1 and UT-A3). Within the past few years, tandem mass spectrometry-based proteomics has played a pivotal role in revealing global changes in the phosphoproteome in response to vasopressin signaling in the renal collecting duct. This type of large-scale 'shotgun' approach has resulted in an exponential increase in the number of phosphoproteins known to be regulated by vasopressin and has expanded on the established signaling mechanisms and kinase pathways regulating collecting duct physiology. This article will provide a brief background on vasopressin action, will highlight a number of recent quantitative phosphoproteomic studies in both native rat kidney and cultured collecting duct cells, and will conclude with a perspective focused on emerging trends in the field of phosphoproteomics.
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Affiliation(s)
- Jason D Hoffert
- Epithelial Systems Biology Laboratory, National Heart, Lung and Blood Institute, Bethesda, MD 20892, USA.
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Moeller HB, Olesen ETB, Fenton RA. Regulation of the water channel aquaporin-2 by posttranslational modification. Am J Physiol Renal Physiol 2011; 300:F1062-73. [DOI: 10.1152/ajprenal.00721.2010] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The cellular functions of many eukaryotic membrane proteins, including the vasopressin-regulated water channel aquaporin-2 (AQP2), are regulated by posttranslational modifications. In this article, we discuss the experimental discoveries that have advanced our understanding of how posttranslational modifications affect AQP2 function, especially as they relate to the role of AQP2 in the kidney. We review the most recent data demonstrating that glycosylation and, in particular, phosphorylation and ubiquitination are mechanisms that regulate AQP2 activity, subcellular sorting and distribution, degradation, and protein interactions. From a clinical perspective, posttranslational modification resulting in protein misrouting or degradation may explain certain forms of nephrogenic diabetes insipidus. In addition to providing major insight into the function and dynamics of renal AQP2 regulation, the analysis of AQP2 posttranslational modification may provide general clues as to the role of posttranslational modification for regulation of other membrane proteins.
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Affiliation(s)
- Hanne B. Moeller
- The Water and Salt Research Center, Department of Anatomy, Aarhus University, Aarhus, Denmark
| | - Emma T. B. Olesen
- The Water and Salt Research Center, Department of Anatomy, Aarhus University, Aarhus, Denmark
| | - Robert A. Fenton
- The Water and Salt Research Center, Department of Anatomy, Aarhus University, Aarhus, Denmark
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50
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Boone M, Kortenoeven MLA, Robben JH, Tamma G, Deen PMT. Counteracting vasopressin-mediated water reabsorption by ATP, dopamine, and phorbol esters: mechanisms of action. Am J Physiol Renal Physiol 2011; 300:F761-71. [PMID: 21209006 DOI: 10.1152/ajprenal.00247.2010] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Water homeostasis is regulated by a wide variety of hormones. When in need for water conservation, vasopressin, released from the brain, binds renal principal cells and initiates a signaling cascade resulting in the insertion of aquaporin-2 (AQP2) water channels in the apical membrane and water reabsorption. Conversely, hormones, including extracellular purines and dopamine, antagonize AVP-induced water permeability, but their mechanism of action is largely unknown, which was investigated here. Addition of these hormones to mpkCCD cells decreased total and plasma membrane abundance of AVP-induced AQP2, partly by increasing its internalization to vesicles and lysosomal degradation. This internalization was ubiquitin dependent, because the hormones increased AQP2 ubiquitination, and the plasma membrane localization of AQP2-K270R, which cannot be monoubiquitinated, was unaffected by these hormones. Both hormones also increased AQP2 phosphorylation at S261, which followed ubiquitination, but was not essential for hormone-induced AQP2 degradation. A similar process occurs in vivo, as incubation of dDAVP-treated kidney slices with both hormones also resulted in the internalization and S261 phosphorylation of AQP2. Both hormones also reduced cAMP and AQP2 mRNA levels, suggesting an additional effect on AQP2 gene transcription. Interestingly, phorbol esters only reduced AQP2 through the first pathway. Together, our results indicate that ATP and dopamine counteract AVP-induced water permeability by increasing AQP2 degradation in lysosomes, preceded by ubiquitin-dependent internalization, and by decreasing AQP2 gene transcription by reducing the AVP-induced cAMP levels.
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Affiliation(s)
- Michelle Boone
- Department of General and Environmental Physiology, University of Bari, Bari, Italy
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