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Zhao Y, Hu ZY, Lou M, Jiang FW, Huang YF, Chen MS, Wang JX, Liu S, Shi YS, Zhu HM, Li JL. AQP1 Deficiency Drives Phthalate-Induced Epithelial Barrier Disruption through Intestinal Inflammation. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2024; 72:15334-15344. [PMID: 38916549 DOI: 10.1021/acs.jafc.4c03764] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/26/2024]
Abstract
Di-2-ethylhexyl phthalate (DEHP) is frequently used as a plasticizer to enhance the plasticity and durability of agricultural products, which pose adverse effects to human health and the environment. Aquaporin 1 (AQP1) is a main water transport channel protein and is involved in the maintenance of intestinal integrity. However, the impact of DEHP exposure on gut health and its potential mechanisms remain elusive. Here, we determined that DEHP exposure induced a compromised duodenum structure, which was concomitant with mitochondrial structural injury of epithelial cells. Importantly, DEHP exposure caused duodenum inflammatory epithelial cell damage and strong inflammatory response accompanied by activating the TLR4/MyD88/NF-κB signaling pathway. Mechanistically, DEHP exposure directly inhibits the expression of AQP1 and thus leads to an inflammatory response, ultimately disrupting duodenum integrity and barrier function. Collectively, our findings uncover the role of AQP1 in phthalate-induced intestinal disorders, and AQP1 could be a promising therapeutic approach for treating patients with intestinal disorders or inflammatory diseases.
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Affiliation(s)
- Yi Zhao
- College of Veterinary Medicine, Northeast Agricultural University, Harbin 150030, P.R. China
- Key Laboratory of the Provincial Education Department of Heilongjiang for Common Animal Disease Prevention and Treatment, Northeast Agricultural University, Harbin 150030, P.R. China
- Heilongjiang Key Laboratory for Laboratory Animals and Comparative Medicine, Northeast Agricultural University, Harbin 150030, P.R. China
| | - Zi-Yan Hu
- College of Veterinary Medicine, Northeast Agricultural University, Harbin 150030, P.R. China
| | - Ming Lou
- College of Veterinary Medicine, Northeast Agricultural University, Harbin 150030, P.R. China
| | - Fu-Wei Jiang
- College of Veterinary Medicine, Northeast Agricultural University, Harbin 150030, P.R. China
| | - Yi-Feng Huang
- College of Veterinary Medicine, Northeast Agricultural University, Harbin 150030, P.R. China
| | - Ming-Shan Chen
- College of Veterinary Medicine, Northeast Agricultural University, Harbin 150030, P.R. China
| | - Jia-Xin Wang
- College of Veterinary Medicine, Northeast Agricultural University, Harbin 150030, P.R. China
| | - Shuo Liu
- College of Veterinary Medicine, Northeast Agricultural University, Harbin 150030, P.R. China
| | - Yu-Sheng Shi
- College of Veterinary Medicine, Northeast Agricultural University, Harbin 150030, P.R. China
| | - Hong-Mei Zhu
- College of Veterinary Medicine, Northeast Agricultural University, Harbin 150030, P.R. China
| | - Jin-Long Li
- College of Veterinary Medicine, Northeast Agricultural University, Harbin 150030, P.R. China
- Key Laboratory of the Provincial Education Department of Heilongjiang for Common Animal Disease Prevention and Treatment, Northeast Agricultural University, Harbin 150030, P.R. China
- Heilongjiang Key Laboratory for Laboratory Animals and Comparative Medicine, Northeast Agricultural University, Harbin 150030, P.R. China
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Castro-Arnau J, Chauvigné F, Toft-Bertelsen TL, Finn RN, MacAulay N, Cerdà J. Aqp4a and Trpv4 mediate regulatory cell volume increase for swimming maintenance of marine fish spermatozoa. Cell Mol Life Sci 2024; 81:285. [PMID: 38969941 DOI: 10.1007/s00018-024-05341-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2024] [Revised: 06/19/2024] [Accepted: 06/28/2024] [Indexed: 07/07/2024]
Abstract
Volume regulation is essential for cell homeostasis and physiological function. Amongst the sensory molecules that have been associated with volume regulation is the transient receptor potential vanilloid 4 (TRPV4), which is a non-selective cation channel that in conjunction with aquaporins, typically controls regulatory volume decrease (RVD). Here we show that the interaction between orthologous AQP4 (Aqp4a) and TRPV4 (Trpv4) is important for regulatory volume increase (RVI) in post-activated marine fish spermatozoa under high osmotic stress. Based upon electrophysiological, volumetric, and in vivo and ex vivo functional experiments using the pharmacological and immunological inhibition of Aqp4a and Trpv4 our model suggests that upon ejaculation and exposure to the hypertonic seawater, spermatozoon shrinkage is initially mediated by water efflux through Aqp1aa in the flagellar tail. The shrinkage results in an increase in intracellular Ca2+ concentration, and the activation of sperm motility and a Na+/K+/2Cl- (NKCC1) cotransporter. The activity of NKCC1 is required for the initiation of cell swelling, which secondarily activates the Aqp4a-Trpv4 complex to facilitate the influx of water via Aqp4a-M43 and Ca2+ via Trpv4 and L-type channels for the mediation of RVI. The inhibitory experiments show that blocking of each of these events prevents either shrinkage or RVI. Our data thus reveal that post-activated marine fish spermatozoa are capable of initiating RVI under a high hypertonic stress, which is essential for the maintenance of sperm motility.
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Affiliation(s)
- Júlia Castro-Arnau
- Institute of Marine Sciences, Spanish National Research Council (CSIC), Barcelona, 08003, Spain
- Institute of Biotechnology and Biomedicine (IBB), Universitat Autònoma de Barcelona, Bellaterra (Barcelona), 08193, Spain
- Department of Cell Biology & Physiology, Washington University in St. Louis School of Medicine, St. Louis, MO, 63110, USA
| | - François Chauvigné
- Institute of Marine Sciences, Spanish National Research Council (CSIC), Barcelona, 08003, Spain
- Institute of Biotechnology and Biomedicine (IBB), Universitat Autònoma de Barcelona, Bellaterra (Barcelona), 08193, Spain
| | | | - Roderick Nigel Finn
- Institute of Biotechnology and Biomedicine (IBB), Universitat Autònoma de Barcelona, Bellaterra (Barcelona), 08193, Spain
- Department of Biological Sciences, University of Bergen, Bergen, 5020, Norway
| | - Nanna MacAulay
- Department of Neuroscience, University of Copenhagen, Copenhagen N, 2200, Denmark
| | - Joan Cerdà
- Institute of Marine Sciences, Spanish National Research Council (CSIC), Barcelona, 08003, Spain.
- Institute of Biotechnology and Biomedicine (IBB), Universitat Autònoma de Barcelona, Bellaterra (Barcelona), 08193, Spain.
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Thormann M, Traube N, Yehia N, Koestler R, Galabova G, MacAulay N, Toft-Bertelsen TL. Toward New AQP4 Inhibitors: ORI-TRN-002. Int J Mol Sci 2024; 25:924. [PMID: 38255997 PMCID: PMC10815436 DOI: 10.3390/ijms25020924] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2023] [Revised: 01/04/2024] [Accepted: 01/09/2024] [Indexed: 01/24/2024] Open
Abstract
Cerebral edema is a life-threatening condition that can cause permanent brain damage or death if left untreated. Existing therapies aim at mitigating the associated elevated intracranial pressure, yet they primarily alleviate pressure rather than prevent edema formation. Prophylactic anti-edema therapy necessitates novel drugs targeting edema formation. Aquaporin 4 (AQP4), an abundantly expressed water pore in mammalian glia and ependymal cells, has been proposed to be involved in cerebral edema formation. A series of novel compounds have been tested for their potential inhibitory effects on AQP4. However, selectivity, toxicity, functional inhibition, sustained therapeutic concentration, and delivery into the central nervous system are major challenges. Employing extensive density-functional theory (DFT) calculations, we identified a previously unreported thermodynamically stable tautomer of the recently identified AQP4-specific inhibitor TGN-020 (2-(nicotinamide)-1,3,4-thiadiazol). This novel form, featuring a distinct hydrogen-bonding pattern, served as a template for a COSMOsim-3D-based virtual screen of proprietary compounds from Origenis™. The screening identified ORI-TRN-002, an electronic homologue of TGN-020, demonstrating high solubility and low protein binding. Evaluating ORI-TRN-002 on AQP4-expressing Xenopus laevis oocytes using a high-resolution volume recording system revealed an IC50 of 2.9 ± 0.6 µM, establishing it as a novel AQP4 inhibitor. ORI-TRN-002 exhibits superior solubility and overcomes free fraction limitations compared to other reported AQP4 inhibitors, suggesting its potential as a promising anti-edema therapy for treating cerebral edema in the future.
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Affiliation(s)
| | - Nadine Traube
- Origenis GmbH, Am Klopferspitz 19A, 82152 Martinsried, Germany
| | - Nasser Yehia
- Origenis GmbH, Am Klopferspitz 19A, 82152 Martinsried, Germany
| | - Roland Koestler
- Origenis GmbH, Am Klopferspitz 19A, 82152 Martinsried, Germany
| | | | - Nanna MacAulay
- Department of Neuroscience, University of Copenhagen, Blegdamsvej 3, 2200 Copenhagen, Denmark
| | - Trine L. Toft-Bertelsen
- Department of Neuroscience, University of Copenhagen, Blegdamsvej 3, 2200 Copenhagen, Denmark
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Abstract
Aquaporins (AQP) working as membrane channels facilitated water transport, play vital roles in various physiological progress including cell migration, energy metabolism, inflammation, etc. They are quite important drug targets, but elusive for discovery due to their undruggable properties. In this chapter, we summarized most fluently used methods for screening AQP inhibitors, including cell swelling assay, cell shrinking assay, and stopped-flow assay. And three classes of AQP inhibitors have been discussed, including metal-related inhibitors, quaternary ammonium salts, and small molecule inhibitors which further divided into four parts, sulfanilamide analogies, TGN-020, antiepileptic drugs, and others. It has been suggested that although they showed inhibition effects on AQP1, AQP3, AQP4, AQP7, or AQP9 in some researches, none of them could be asserted as AQP inhibitors to some extent. Discovering AQP inhibitors is a big challenge, but if successful, it will be a great contribution for human health.
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Affiliation(s)
- Shuyuan Wang
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Pharmacology, School of Basic Medical Sciences, Peking University, Beijing, China
| | | | - Baoxue Yang
- School of Basic Medical Sciences, Peking University, Beijing, China.
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Theologou M, Natsis K, Kouskouras K, Chatzinikolaou F, Varoutis P, Skoulios N, Tsitouras V, Tsonidis C. Cerebrospinal Fluid Homeostasis and Hydrodynamics: A Review of Facts and Theories. Eur Neurol 2022; 85:313-325. [PMID: 35405679 DOI: 10.1159/000523709] [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: 12/03/2021] [Accepted: 02/04/2022] [Indexed: 12/13/2022]
Abstract
BACKGROUND AND PURPOSE According to the classical hypothesis, the cerebrospinal fluid (CSF) is actively secreted inside the brain's ventricular system, predominantly by the choroid plexuses, before flowing unidirectionally in a cranio-caudal orientation toward the arachnoid granulations (AGs), where it is reabsorbed into the dural venous sinuses. This concept has been accepted as a doctrine for more than 100 years and was subjected only to minor modifications. Its inability to provide an adequate explanation to questions arising from the everyday clinical practice, in addition to the ever growing pool of experimental data contradicting it, has led to the identification of its limitations. Literature includes an increasing number of studies suggesting a more complex mechanism than that previously described. This review article summarizes the proposed mechanisms of CSF regulation, referring to the key clinical and experimental developments supporting or defying them. METHODS A non-systematical literature search of the major databases was performed for studies on the mechanisms of CSF homeostasis. Gray literature was additionally assessed employing a hand-search technique. No restrictions were imposed regarding the time, language, or type of publication. CONCLUSION CSF secretion and absorption are expected to take place throughout the entire brain's capillaries network under the regulation of hydrostatic and osmotic gradients. The unidirectional flow is defied, highlighting the possibility of its complete absence. The importance of AGs is brought into question, potentiating the significance of the lymphatic system as the primary site of reabsorption. However, the definition of hydrocephalus and its treatment strategies remain strongly associated with the classical hypothesis.
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Affiliation(s)
- Marios Theologou
- Second Department of Neurosurgery, Aristotle University of Thessaloniki, General Hospital of Thessaloniki Hippokratio, Thessaloniki, Greece
| | - Konstantinos Natsis
- Department of Anatomy and Surgical Anatomy, School of Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Konstantinos Kouskouras
- Department of Radiology, AHEPA University Hospital, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Fotios Chatzinikolaou
- Department of Forensic Medicine and Toxicology, Medical School, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Panagiotis Varoutis
- Second Department of Neurosurgery, Aristotle University of Thessaloniki, General Hospital of Thessaloniki Hippokratio, Thessaloniki, Greece
| | - Nikolaos Skoulios
- Second Department of Neurosurgery, Aristotle University of Thessaloniki, General Hospital of Thessaloniki Hippokratio, Thessaloniki, Greece
| | - Vassilios Tsitouras
- Second Department of Neurosurgery, Aristotle University of Thessaloniki, General Hospital of Thessaloniki Hippokratio, Thessaloniki, Greece
| | - Christos Tsonidis
- Second Department of Neurosurgery, Aristotle University of Thessaloniki, General Hospital of Thessaloniki Hippokratio, Thessaloniki, Greece
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Oztopuz O, Coskun O, Buyuk B. Alterations in aquaporin gene expression level on cyclophosphamide-induced cardiac injury and possible protective role of Ganoderma lucidum. Biologia (Bratisl) 2021. [DOI: 10.1007/s11756-021-00817-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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Rossino G, Rui M, Pozzetti L, Schepmann D, Wünsch B, Zampieri D, Pellavio G, Laforenza U, Rinaldi S, Colombo G, Morelli L, Linciano P, Rossi D, Collina S. Setup and Validation of a Reliable Docking Protocol for the Development of Neuroprotective Agents by Targeting the Sigma-1 Receptor (S1R). Int J Mol Sci 2020; 21:E7708. [PMID: 33081037 PMCID: PMC7589021 DOI: 10.3390/ijms21207708] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 10/06/2020] [Accepted: 10/14/2020] [Indexed: 12/16/2022] Open
Abstract
Sigma-1 receptor (S1R) is a promising molecular target for the development of novel effective therapies against neurodegenerative diseases. To speed up the discovery of new S1R modulators, herein we report the development of a reliable in silico protocol suitable to predict the affinity of small molecules against S1R. The docking method was validated by comparing the computational calculated Ki values of a test set of new aryl-aminoalkyl-ketone with experimental determined binding affinity. The druggability profile of the new compounds, with particular reference to the ability to cross the blood-brain barrier (BBB) was further predicted in silico. Moreover, the selectivity over Sigma-2 receptor (S2R) and N-methyl-D-aspartate (NMDA) receptor, another protein involved in neurodegeneration, was evaluated. 1-([1,1'-biphenyl]-4-yl)-4-(piperidin-1-yl)butan-1-one (12) performed as the best compound and was further investigated for acetylcholinesterase (AchE) inhibitor activity and determination of antioxidant activity mediated by aquaporins (AQPs). With a good affinity against both S1R and NMDA receptor, good selectivity over S2R and favorable BBB penetration potential together with its AChE inhibitory activity and its ability to exert antioxidant effects through modulation of AQPs, 12 represents a viable candidate for further development as a neuroprotective agent.
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Affiliation(s)
- Giacomo Rossino
- Department of Drug Sciences, Medicinal Chemistry and Pharmaceutical Technology Section, University of Pavia, V.le Taramelli 12, 27100 Pavia, Italy; (G.R.); (M.R.); (L.P.); (P.L.); (D.R.)
| | - Marta Rui
- Department of Drug Sciences, Medicinal Chemistry and Pharmaceutical Technology Section, University of Pavia, V.le Taramelli 12, 27100 Pavia, Italy; (G.R.); (M.R.); (L.P.); (P.L.); (D.R.)
| | - Luca Pozzetti
- Department of Drug Sciences, Medicinal Chemistry and Pharmaceutical Technology Section, University of Pavia, V.le Taramelli 12, 27100 Pavia, Italy; (G.R.); (M.R.); (L.P.); (P.L.); (D.R.)
| | - Dirk Schepmann
- Institute of Pharmaceutical and Medicinal Chemistry, University of Münster, Corrensstraße 48, 48149 Münster, Germany; (D.S.); (B.W.)
| | - Bernhard Wünsch
- Institute of Pharmaceutical and Medicinal Chemistry, University of Münster, Corrensstraße 48, 48149 Münster, Germany; (D.S.); (B.W.)
| | - Daniele Zampieri
- Department of Chemical and Pharmaceutical Sciences, University of Trieste, 30126 Trieste, Italy;
| | - Giorgia Pellavio
- Department of Molecular Medicine, Human Physiology Unit, University of Pavia, via Forlanini 6, 27100 Pavia, Italy; (G.P.); (U.L.)
| | - Umberto Laforenza
- Department of Molecular Medicine, Human Physiology Unit, University of Pavia, via Forlanini 6, 27100 Pavia, Italy; (G.P.); (U.L.)
| | | | - Giorgio Colombo
- Dipartimento di Chimica, Università di Pavia, V.le Taramelli 12, 27100 Pavia, Italy;
| | - Laura Morelli
- Department of Medical Biotechnology and Translational Medicine, University of Milan, Via Saldini 50, 20133 Milan, Italy;
| | - Pasquale Linciano
- Department of Drug Sciences, Medicinal Chemistry and Pharmaceutical Technology Section, University of Pavia, V.le Taramelli 12, 27100 Pavia, Italy; (G.R.); (M.R.); (L.P.); (P.L.); (D.R.)
| | - Daniela Rossi
- Department of Drug Sciences, Medicinal Chemistry and Pharmaceutical Technology Section, University of Pavia, V.le Taramelli 12, 27100 Pavia, Italy; (G.R.); (M.R.); (L.P.); (P.L.); (D.R.)
| | - Simona Collina
- Department of Drug Sciences, Medicinal Chemistry and Pharmaceutical Technology Section, University of Pavia, V.le Taramelli 12, 27100 Pavia, Italy; (G.R.); (M.R.); (L.P.); (P.L.); (D.R.)
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8
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Toft-Bertelsen TL, Larsen BR, Christensen SK, Khandelia H, Waagepetersen HS, MacAulay N. Clearance of activity-evoked K + transients and associated glia cell swelling occur independently of AQP4: A study with an isoform-selective AQP4 inhibitor. Glia 2020; 69:28-41. [PMID: 32506554 DOI: 10.1002/glia.23851] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Revised: 05/11/2020] [Accepted: 05/13/2020] [Indexed: 12/29/2022]
Abstract
The mammalian brain consists of 80% water, which is continuously shifted between different compartments and cellular structures by mechanisms that are, to a large extent, unresolved. Aquaporin 4 (AQP4) is abundantly expressed in glia and ependymal cells of the mammalian brain and has been proposed to act as a gatekeeper for brain water dynamics, predominantly based on studies utilizing AQP4-deficient mice. However, these mice have a range of secondary effects due to the gene deletion. An efficient and selective AQP4 inhibitor has thus been sorely needed to validate the results obtained in the AQP4-/- mice to quantify the contribution of AQP4 to brain fluid dynamics. In AQP4-expressing Xenopus laevis oocytes monitored by a high-resolution volume recording system, we here demonstrate that the compound TGN-020 is such a selective AQP4 inhibitor. TGN-020 targets the tested species of AQP4 with an IC50 of ~3.5 μM, but displays no inhibitory effect on the other AQPs (AQP1-AQP9). With this tool, we employed rat hippocampal slices and ion-sensitive microelectrodes to determine the role of AQP4 in glia cell swelling following neuronal activity. TGN-020-mediated inhibition of AQP4 did not prevent stimulus-induced extracellular space shrinkage, nor did it slow clearance of the activity-evoked K+ transient. These data, obtained with a verified isoform-selective AQP4 inhibitor, indicate that AQP4 is not required for the astrocytic contribution to the K+ clearance or the associated extracellular space shrinkage.
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Affiliation(s)
- Trine Lisberg Toft-Bertelsen
- Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Brian Roland Larsen
- Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Sofie Kjellerup Christensen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Himanshu Khandelia
- Department of Physics, Chemistry and Pharmacy, Faculty of Science, University of Southern Denmark, Odense, Denmark
| | - Helle S Waagepetersen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Nanna MacAulay
- Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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Chow PH, Kourghi M, Pei JV, Nourmohammadi S, Yool AJ. 5-Hydroxymethyl-Furfural and Structurally Related Compounds Block the Ion Conductance in Human Aquaporin-1 Channels and Slow Cancer Cell Migration and Invasion. Mol Pharmacol 2020; 98:38-48. [PMID: 32434851 DOI: 10.1124/mol.119.119172] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Accepted: 04/20/2020] [Indexed: 12/18/2022] Open
Abstract
Aquaporin-1 (AQP1) dual water and ion channels enhance migration and invasion when upregulated in leading edges of certain classes of cancer cells. Work here identifies structurally related furan compounds as novel inhibitors of AQP1 ion channels. 5-Hydroxymethyl-2-furfural (5HMF), a component of natural medicinal honeys, and three structurally related compounds, 5-nitro-2-furoic acid (5NFA), 5-acetoxymethyl-2-furaldehyde (5AMF), and methyl-5-nitro-2-furoate (M5NF), were analyzed for effects on water and ion channel activities of human AQP1 channels expressed in Xenopus oocytes. Two-electrode voltage clamp showed dose-dependent block of the AQP1 ion current by 5HMF (IC50 0.43 mM), 5NFA (IC50 1.2 mM), and 5AMF (IC50 ∼3 mM) but no inhibition by M5NF. In silico docking predicted the active ligands interacted with glycine 165, located in loop D gating domains surrounding the intracellular vestibule of the tetrameric central pore. Water fluxes through separate intrasubunit pores were unaltered by the furan compounds (at concentrations up to 5 mM). Effects on cell migration, invasion, and cytoskeletal organization in vitro were tested in high-AQP1-expressing cancer lines, colon cancer (HT29) and AQP1-expressing breast cancer (MDA), and low-AQP1-expressing SW480. 5HMF, 5NFA, and 5AMF selectively impaired cell motility in the AQP1-enriched cell lines. In contrast, M5NF immobilized all the cancer lines by disrupting actin cytoskeleton. No reduction in cell viability was observed at doses that were effective in blocking motility. These results define furans as a new class of AQP1 ion channel inhibitors for basic research and potential lead compounds for development of therapeutic agents targeting aquaporin channel activity. SIGNIFICANCE STATEMENT: 5-Hydroxymethyl-2-furfural (5HMF), a component of natural medicinal honeys, blocks the ion conductance but not the water flux through human Aquaporin-1 (AQP1) channels and impairs AQP1-dependent cell migration and invasiveness in cancer cell lines. Analyses of 5HMT and structural analogs demonstrate a structure-activity relationship for furan compounds, supported by in silico docking modeling. This work identifies new low-cost pharmacological antagonists for AQP1 available to researchers internationally. Furans merit consideration as a new class of therapeutic agents for controlling cancer metastasis.
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Affiliation(s)
- Pak Hin Chow
- Adelaide Medical School, University of Adelaide, Adelaide, Australia (P.H.C., M.K., J.V.P., S.N., A.J.Y.) and College of Science, The Australian National University, Canberra, Australia (J.V.P.)
| | - Mohamad Kourghi
- Adelaide Medical School, University of Adelaide, Adelaide, Australia (P.H.C., M.K., J.V.P., S.N., A.J.Y.) and College of Science, The Australian National University, Canberra, Australia (J.V.P.)
| | - Jinxin V Pei
- Adelaide Medical School, University of Adelaide, Adelaide, Australia (P.H.C., M.K., J.V.P., S.N., A.J.Y.) and College of Science, The Australian National University, Canberra, Australia (J.V.P.)
| | - Saeed Nourmohammadi
- Adelaide Medical School, University of Adelaide, Adelaide, Australia (P.H.C., M.K., J.V.P., S.N., A.J.Y.) and College of Science, The Australian National University, Canberra, Australia (J.V.P.)
| | - Andrea J Yool
- Adelaide Medical School, University of Adelaide, Adelaide, Australia (P.H.C., M.K., J.V.P., S.N., A.J.Y.) and College of Science, The Australian National University, Canberra, Australia (J.V.P.)
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10
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Kannan A, Panneerselvam A, Mariajoseph-Antony LF, Loganathan C, Prahalathan C. Role of Aquaporins in Spermatogenesis and Testicular Steroidogenesis. J Membr Biol 2020; 253:109-114. [DOI: 10.1007/s00232-020-00114-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Accepted: 03/14/2020] [Indexed: 01/25/2023]
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11
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Bumetanide Suppression of Angiogenesis in a Rat Model of Oxygen-Induced Retinopathy. Int J Mol Sci 2020; 21:ijms21030987. [PMID: 32024231 PMCID: PMC7037744 DOI: 10.3390/ijms21030987] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 01/24/2020] [Accepted: 01/29/2020] [Indexed: 12/18/2022] Open
Abstract
Aquaporins (AQPs) are involved in hypoxia-induced angiogenesis and retinal damage. Bumetanide is a diuretic agent, Na+/K+/Cl− cotransporter (NKCC1), and AQP 1–4 inhibitor. We tested the hypothesis that early postnatal treatment with bumetanide suppresses biomarkers of angiogenesis and decreases severe retinopathy oxygen-induced retinopathy (OIR). Neonatal rats were exposed at birth (P0) to either (1) room air (RA); (2) hyperoxia (50% O2); or (3) intermittent hypoxia (IH) consisting of 50% O2 with brief, clustered episodes of 12% O2 from P0 to postnatal day 14 (P14), during which they were treated intraperitoneally (IP) with bumetanide (0.1 mg/kg/day) or an equivalent volume of saline, on P0–P2. Pups were examined at P14 or allowed to recover in RA from P14–P21. Retinal angiogenesis, morphometry, pathology, AQPs, and angiogenesis biomarkers were determined at P14 and P21. Bumetanide reduced vascular abnormalities associated with severe OIR. This was associated with reductions in AQP-4 and VEGF. Bumetanide suppressed sVEGFR-1 in the serum and vitreous fluid, but levels were increased in the ocular tissues during recovery. Similar responses were noted for IGF-I. In this model, early systemic bumetanide administration reduces severe OIR, the benefits of which appear to be mediated via suppression of AQP-4 and VEGF. Further studies are needed to determine whether bumetanide at the right doses may be considered a potential pharmacologic agent to treat retinal neovascularization.
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12
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Suzuki Y, Kitaura H, Nakamura Y, Kakita A, Huber VJ, Capozzoli N, Kwee IL, Nakada T. Skull diploë is rich in aquaporin-4. Heliyon 2020; 6:e03259. [PMID: 32042979 PMCID: PMC7002819 DOI: 10.1016/j.heliyon.2020.e03259] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2019] [Revised: 10/10/2019] [Accepted: 01/15/2020] [Indexed: 12/03/2022] Open
Abstract
Aquaporin-4 (AQP4) is a water conducting membrane integral protein channel which is widely expressed in the astrocyte system of the brain. During the development of the AQP4 positron emission tomography (PET) imaging agent [11C]TGN-020 (N-(1,3,4-thiadiazol-2-yl)pyridine-3-[11C]-carboxamide), significant radioligand uptake was observed in the skull, where there was no known distribution of any aquaporin family proteins. Herein we confirmed via a newly developed method for bone-tissue immunohistology, a hitherto unrecognized distribution of AQP4, and not AQP1, in the skull. Other bony structures, by contrast, showed virtually no uptake of [11C]TGN-020, and likewise, do not express either AQP4 or AQP1. Immunohistological analysis demonstrated that the AQP4 expression in the skull is restricted to the diploë. Consequently, we suspect AQP4 plays a pivotal role in the formation and maintenance of yellow marrow and the diploë. However, elucidating the exact nature of that role will require further studies.
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Affiliation(s)
- Yuji Suzuki
- Center for Integrated Human Brain Science, Brain Research Institute, University of Niigata, Japan
| | - Hiroki Kitaura
- Center for Integrated Human Brain Science, Brain Research Institute, University of Niigata, Japan.,Department of Pathology, Brain Research Institute, University of Niigata, Japan
| | - Yukimi Nakamura
- Center for Integrated Human Brain Science, Brain Research Institute, University of Niigata, Japan
| | - Akiyoshi Kakita
- Department of Pathology, Brain Research Institute, University of Niigata, Japan
| | - Vincent J Huber
- Center for Integrated Human Brain Science, Brain Research Institute, University of Niigata, Japan
| | | | - Ingrid L Kwee
- Center for Integrated Human Brain Science, Brain Research Institute, University of Niigata, Japan.,Department of Neurology, University of California, Davis, USA
| | - Tsutomu Nakada
- Center for Integrated Human Brain Science, Brain Research Institute, University of Niigata, Japan.,Department of Neurology, University of California, Davis, USA
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Oliveira Pinho J, Matias M, Gaspar MM. Emergent Nanotechnological Strategies for Systemic Chemotherapy against Melanoma. NANOMATERIALS (BASEL, SWITZERLAND) 2019; 9:E1455. [PMID: 31614947 PMCID: PMC6836019 DOI: 10.3390/nano9101455] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/15/2019] [Revised: 10/04/2019] [Accepted: 10/10/2019] [Indexed: 12/24/2022]
Abstract
Melanoma is an aggressive form of skin cancer, being one of the deadliest cancers in the world. The current treatment options involve surgery, radiotherapy, targeted therapy, immunotherapy and the use of chemotherapeutic agents. Although the last approach is the most used, the high toxicity and the lack of efficacy in advanced stages of the disease have demanded the search for novel bioactive molecules and/or efficient drug delivery systems. The current review aims to discuss the most recent advances on the elucidation of potential targets for melanoma treatment, such as aquaporin-3 and tyrosinase. In addition, the role of nanotechnology as a valuable strategy to effectively deliver selective drugs is emphasized, either incorporating/encapsulating synthetic molecules or natural-derived compounds in lipid-based nanosystems such as liposomes. Nanoformulated compounds have been explored for their improved anticancer activity against melanoma and promising results have been obtained. Indeed, they displayed improved physicochemical properties and higher accumulation in tumoral tissues, which potentiated the efficacy of the compounds in pre-clinical experiments. Overall, these experiments opened new doors for the discovery and development of more effective drug formulations for melanoma treatment.
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Affiliation(s)
- Jacinta Oliveira Pinho
- Research Institute for Medicines, iMed.ULisboa, Faculty of Pharmacy, Universidade de Lisboa, Av. Prof. Gama Pinto, 1649-003 Lisboa, Portugal.
| | - Mariana Matias
- Research Institute for Medicines, iMed.ULisboa, Faculty of Pharmacy, Universidade de Lisboa, Av. Prof. Gama Pinto, 1649-003 Lisboa, Portugal.
| | - Maria Manuela Gaspar
- Research Institute for Medicines, iMed.ULisboa, Faculty of Pharmacy, Universidade de Lisboa, Av. Prof. Gama Pinto, 1649-003 Lisboa, Portugal.
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Suzuki Y, Nakamura Y, Yamada K, Kurabe S, Okamoto K, Aoki H, Kitaura H, Kakita A, Fujii Y, Huber VJ, Igarashi H, Kwee IL, Nakada T. Aquaporin Positron Emission Tomography Differentiates Between Grade III and IV Human Astrocytoma. Neurosurgery 2019. [PMID: 28645205 PMCID: PMC5952963 DOI: 10.1093/neuros/nyx314] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
BACKGROUND Aquaporin (AQP) water channels play a significant role in mesenchymal microvascular proliferation and infiltrative growth. AQPs are highly expressed in malignant astrocytomas, and a positive correlation is observed between their expression levels and histological tumor grade. OBJECTIVE To examine the utility of aquaporin positron emission tomography (PET) for differentiating between astrocytoma grade III and grade IV using the AQP radioligand [11C]TGN-020. METHODS Fifteen astrocytoma patients, grade III (n = 7) and grade IV (n = 8), and 10 healthy volunteers underwent [11C]TGN-020 aquaporin PET imaging. Surgical tissues of astrocytoma patients were examined for histopathological grading using the WHO classification standard and expression of AQP1 and AQP4 immunohistochemically. RESULTS Mean standardized uptake values of astrocytoma grade III and IV (0.51 ± 0.11 vs 1.50 ± 0.44, respectively) were higher than normal white matter (0.17 ± 0.02, P < .001) for both tumor grades. Importantly, mean standardized uptake values of astrocytoma grade IV were significantly higher than grade III (P < .01). CONCLUSION Our study demonstrated that [11C]TGN-020 aquaporin PET imaging differentiated between astrocytoma grades III and IV. We suggest its clinical application as a noninvasive diagnostic tool would lead to advancements in the management of these malignant brain tumors.
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Affiliation(s)
- Yuji Suzuki
- Center for Integrated Human Brain Sci-ence, Brain Research Institute, University of Niigata, Niigata, Japan
| | - Yukihiro Nakamura
- Center for Integrated Human Brain Sci-ence, Brain Research Institute, University of Niigata, Niigata, Japan
| | - Kenichi Yamada
- Center for Integrated Human Brain Sci-ence, Brain Research Institute, University of Niigata, Niigata, Japan
| | - Satoshi Kurabe
- Center for Integrated Human Brain Sci-ence, Brain Research Institute, University of Niigata, Niigata, Japan.,Department of Neurosurgery, Brain Research Ins-titute, University of Niigata, Niigata, Japan
| | - Kouichirou Okamoto
- Department of Neurosurgery, Brain Research Ins-titute, University of Niigata, Niigata, Japan
| | - Hiroshi Aoki
- Department of Neurosurgery, Brain Research Ins-titute, University of Niigata, Niigata, Japan
| | - Hiroki Kitaura
- Center for Integrated Human Brain Sci-ence, Brain Research Institute, University of Niigata, Niigata, Japan.,Department of Pathology, Brain Research Institute, University of Niigata, Niigata, Japan
| | - Akiyoshi Kakita
- Department of Pathology, Brain Research Institute, University of Niigata, Niigata, Japan
| | - Yukihiko Fujii
- Department of Neurosurgery, Brain Research Ins-titute, University of Niigata, Niigata, Japan
| | - Vincent J Huber
- Center for Integrated Human Brain Sci-ence, Brain Research Institute, University of Niigata, Niigata, Japan
| | - Hironaka Igarashi
- Center for Integrated Human Brain Sci-ence, Brain Research Institute, University of Niigata, Niigata, Japan
| | - Ingrid L Kwee
- Department of Neurology, University of California, Davis, Davis, California
| | - Tsutomu Nakada
- Center for Integrated Human Brain Sci-ence, Brain Research Institute, University of Niigata, Niigata, Japan
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Abir-Awan M, Kitchen P, Salman MM, Conner MT, Conner AC, Bill RM. Inhibitors of Mammalian Aquaporin Water Channels. Int J Mol Sci 2019; 20:ijms20071589. [PMID: 30934923 PMCID: PMC6480248 DOI: 10.3390/ijms20071589] [Citation(s) in RCA: 80] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Revised: 03/25/2019] [Accepted: 03/26/2019] [Indexed: 01/29/2023] Open
Abstract
Aquaporins (AQPs) are water channel proteins that are essential to life, being expressed in all kingdoms. In humans, there are 13 AQPs, at least one of which is found in every organ system. The structural biology of the AQP family is well-established and many functions for AQPs have been reported in health and disease. AQP expression is linked to numerous pathologies including tumor metastasis, fluid dysregulation, and traumatic injury. The targeted modulation of AQPs therefore presents an opportunity to develop novel treatments for diverse conditions. Various techniques such as video microscopy, light scattering and fluorescence quenching have been used to test putative AQP inhibitors in both AQP-expressing mammalian cells and heterologous expression systems. The inherent variability within these methods has caused discrepancy and many molecules that are inhibitory in one experimental system (such as tetraethylammonium, acetazolamide, and anti-epileptic drugs) have no activity in others. Some heavy metal ions (that would not be suitable for therapeutic use) and the compound, TGN-020, have been shown to inhibit some AQPs. Clinical trials for neuromyelitis optica treatments using anti-AQP4 IgG are in progress. However, these antibodies have no effect on water transport. More research to standardize high-throughput assays is required to identify AQP modulators for which there is an urgent and unmet clinical need.
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Affiliation(s)
- Mohammed Abir-Awan
- School of Life & Health Sciences, Aston University, Aston Triangle, Birmingham B4 7ET, UK.
| | - Philip Kitchen
- School of Life & Health Sciences, Aston University, Aston Triangle, Birmingham B4 7ET, UK.
| | - Mootaz M Salman
- Department of Cell Biology, Harvard Medical School, 200 Longwood Avenue, Boston, MA 02115, USA.
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, 200 Longwood Avenue, Boston, MA 02115, USA.
| | - Matthew T Conner
- Research Institute of Health Sciences, School of Sciences, University of Wolverhampton, Wolverhampton WV1 1LY, UK.
| | - Alex C Conner
- Institute of Clinical Sciences, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK.
| | - Roslyn M Bill
- School of Life & Health Sciences, Aston University, Aston Triangle, Birmingham B4 7ET, UK.
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De Simone G. Targeted treatment of anaerobic cancer. Patent evaluation of US2016279084 and US2017056350. Expert Opin Ther Pat 2018; 29:1-6. [PMID: 30556445 DOI: 10.1080/13543776.2019.1558210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
INTRODUCTION Based on the initial studies of J. Folkman in 1970s, which led to the proposal of the antiangiogenic therapy, many drugs targeting VEGF or its receptors have been developed with some of them approved for cancer treatment. However, these molecules so far have shown only a limited effect on survival benefits in patients. Thus, new approaches are needed to treat this disease. Considering that cancer utilizes both aerobic and anaerobic glycolytic pathway, authors of patents US2016279084 and US2017056350 propose a method to eradicate the disease, able to affect both metabolic pathways. Areas covered: Patent US2016279084 describes a method consisting of the utilization of either a pharmaceutical cocktail containing antiglycolytic agents (a lactate transporter inhibitor and a NKCC inhibitor) and an angiogenesis inhibitor or a pharmaceutical cocktail containing a lactate transporter inhibitor and an angiogenesis inhibitor in combination with blood vessel occlusion. Patent US2017056350 is strictly related to US2016279084; indeed, it proposes a method consisting of blood vessel occlusion and treatment with a pharmaceutical cocktail, containing the carbonic anhydrase inhibitor bumetanide in presence or absence of an angiogenesis inhibitor. Expert opinion: Although the proposed methodology is very interesting and promising, further studies are necessary to assess the clinical applicability of the inventions.
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Er Shen Wan extract alleviates polyuria and regulates AQP 2 and AVPR 2 in a rat model of spleen-kidney Yang deficiency-induced diarrhea. Biomed Pharmacother 2018; 110:302-311. [PMID: 30522016 DOI: 10.1016/j.biopha.2018.11.147] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Revised: 11/27/2018] [Accepted: 11/28/2018] [Indexed: 02/08/2023] Open
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Er Shen Wan (ESW), has been empirically used for treating spleen-kidney Yang deficiency (SKYD) syndrome in Traditional Chinese medicine (TCM) for centuries and shows a variety of activities. The medicinal formula is a mixture of two component herbs, Psoraleae Fructus (PF, Bu-Gu-Zhi in Chinese) and Myristicae Semen (MS, Rou-Dou-Kou in Chinese). The current study was designed to evaluate ESWP antidiuretic treatment of polyuria and to explore potential mechanisms of renal water metabolism in the rat model of SKYD-induced diarrhea. MATERIALS AND METHODS An animal model of 'SKYD-induced diarrhea syndrome' has been established to evaluate the therapeutic effect and action mechanism according to the clinical syndrome and symptoms. The optimal dose (3.5 g/kg) of ESWP was given to rats by gavage for two weeks. Urinary volumes after 24 h were recorded. After the end of the trial, macroscopic morphological and histological examination of the kidney were conducted. Serum levels of Arginine vasopressin (AVP) and aldosterone (ALD) were also measured. Additionally, quantitative real-time RT-PCR (RT-qPCR) and immunohistochemistry (IHC) analyses were performed to clarify the regulation of aquaporin 2 (AQP 2) and arginine vasopressin type 2 receptor (AVPR 2) in the kidney at the gene and tissue expression levels respectively. RESULTS After the administration of ESWP, urinary output volume after 24 h was found to be significantly decreased in rats. Elevated plasma levels of AVP and ALD were detected. Histological kidney damage appeared to be impeded, and histological disease scores were reduced. In addition, the expression levels of AQP 2 and AVPR 2 were significantly increased. CONCLUSION This study suggests that ESWP may elicit significant effects on the treatment of polyuria. Potential mechanisms at least partially involve hormone regulation, and alleviating renal pathological damage. Simultaneously, ESWP may alter renal water absorption by increasing AQP 2 and AVPR 2 expression levels. Thus, the in vivo experimental evidence indicates that ESWP has a therapeutic effect on the SKYD syndrome, which is consistent with its traditional usage.
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Brandt C, Seja P, Töllner K, Römermann K, Hampel P, Kalesse M, Kipper A, Feit PW, Lykke K, Toft-Bertelsen TL, Paavilainen P, Spoljaric I, Puskarjov M, MacAulay N, Kaila K, Löscher W. Bumepamine, a brain-permeant benzylamine derivative of bumetanide, does not inhibit NKCC1 but is more potent to enhance phenobarbital's anti-seizure efficacy. Neuropharmacology 2018; 143:186-204. [DOI: 10.1016/j.neuropharm.2018.09.025] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Revised: 08/30/2018] [Accepted: 09/16/2018] [Indexed: 01/01/2023]
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Systemic Hypertension Effects on the Ciliary Body and Iris. An Immunofluorescence Study with Aquaporin 1, Aquaporin 4, and Na⁺, K⁺ ATPase in Hypertensive Rats. Cells 2018; 7:cells7110210. [PMID: 30428541 PMCID: PMC6262422 DOI: 10.3390/cells7110210] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Revised: 11/08/2018] [Accepted: 11/09/2018] [Indexed: 11/16/2022] Open
Abstract
Aquaporin 1 (AQP1) and aquaporin 4 (AQP4) have been identified in the eye as playing an essential role in the formation of the aqueous humor along with the Na+/K+ ATPase pump. Different authors have described the relationship between blood pressure, aqueous humor production, and intraocular pressure with different conclusions, with some authors supporting a positive correlation between blood pressure and intraocular pressure while others disagree. The aim of this work was to study the effect of high blood pressure on the proteins involved in the production of aqueous humor in the ciliary body (CB) and iris. For this purpose, we used the eyes of spontaneously hypertensive rats (SHR) and their control Wistar-Kyoto rats (WKY). Immunofluorescence was performed in different eye structures to analyze the effects of hypertension in the expression of AQP1, AQP4, and the Na+/K+ ATPase α1 and α2 subunits. The results showed an increase in AQP1 and Na+/K+ ATPase α1 and a decrease in AQP4 and Na+/K+ ATPase α2 in the CB of SHR, while an increase in AQP4 and no significant differences in AQP1 were found in the iris. Therefore, systemic hypertension produced changes in the proteins implicated in the movement of water in the CB and iris that could influence the production rate of aqueous humor, which would be affected depending on the duration of systemic hypertension.
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Nakada T, Kwee IL. Fluid Dynamics Inside the Brain Barrier: Current Concept of Interstitial Flow, Glymphatic Flow, and Cerebrospinal Fluid Circulation in the Brain. Neuroscientist 2018; 25:155-166. [PMID: 29799313 PMCID: PMC6416706 DOI: 10.1177/1073858418775027] [Citation(s) in RCA: 80] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The discovery of the water specific channel, aquaporin, and abundant expression
of its isoform, aquaporin-4 (AQP-4), on astrocyte endfeet brought about
significant advancements in the understanding of brain fluid dynamics. The brain
is protected by barriers preventing free access of systemic fluid. The same
barrier system, however, also isolates brain interstitial fluid from the
hydro-dynamic effect of the systemic circulation. The systolic force of the
heart, an essential factor for proper systemic interstitial fluid circulation,
cannot be propagated to the interstitial fluid compartment of the brain. Without
a proper alternative mechanism, brain interstitial fluid would stay stagnant.
Water influx into the peri-capillary Virchow-Robin space (VRS) through the
astrocyte AQP-4 system compensates for this hydrodynamic shortage essential for
interstitial flow, introducing the condition virtually identical to systemic
circulation, which by virtue of its fenestrated capillaries creates appropriate
interstitial fluid motion. Interstitial flow in peri-arterial VRS constitutes an
essential part of the clearance system for β-amyloid, whereas interstitial flow
in peri-venous VRS creates bulk interstitial fluid flow, which, together with
the choroid plexus, creates the necessary ventricular cerebrospinal fluid (CSF)
volume for proper CSF circulation.
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Affiliation(s)
- Tsutomu Nakada
- 1 Center for Integrated Human Brain Science, Brain Research Institute, University of Niigata, Niigata, Japan
| | - Ingrid L Kwee
- 2 Department of Neurology, University of California Davis, Sacramento, CA, USA
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Kourghi M, De Ieso ML, Nourmohammadi S, Pei JV, Yool AJ. Identification of Loop D Domain Amino Acids in the Human Aquaporin-1 Channel Involved in Activation of the Ionic Conductance and Inhibition by AqB011. Front Chem 2018; 6:142. [PMID: 29755973 PMCID: PMC5934433 DOI: 10.3389/fchem.2018.00142] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Accepted: 04/12/2018] [Indexed: 01/08/2023] Open
Abstract
Aquaporins are integral proteins that facilitate the transmembrane transport of water and small solutes. In addition to enabling water flux, mammalian Aquaporin-1 (AQP1) channels activated by cyclic GMP can carry non-selective monovalent cation currents, selectively blocked by arylsulfonamide compounds AqB007 (IC50 170 μM) and AqB011 (IC50 14 μM). In silico models suggested that ligand docking might involve the cytoplasmic loop D (between AQP1 transmembrane domains 4 and 5), but the predicted site of interaction remained to be tested. Work here shows that mutagenesis of two conserved arginine residues in loop D slowed the activation of the AQP1 ion conductance and impaired the sensitivity of the channel to block by AqB011. Substitution of residues in loop D with proline showed effects on ion conductance amplitude that varied with position, suggesting that the structural conformation of loop D is important for AQP1 channel gating. Human AQP1 wild type, AQP1 mutant channels with alanines substituted for two arginines (R159A+R160A), and mutants with proline substituted for single residues threonine (T157P), aspartate (D158P), arginine (R159P, R160P), or glycine (G165P) were expressed in Xenopus laevis oocytes. Conductance responses were analyzed by two-electrode voltage clamp. Optical osmotic swelling assays and confocal microscopy were used to confirm mutant and wild type AQP1-expressing oocytes were expressed in the plasma membrane. After application of membrane-permeable cGMP, R159A+R160A channels had a significantly slower rate of activation as compared with wild type, consistent with impaired gating. AQP1 R159A+R160A channels showed no significant block by AqB011 at 50 μM, in contrast to the wild type channel which was blocked effectively. T157P, D158P, and R160P mutations had impaired activation compared to wild type; R159P showed no significant effect; and G165P appeared to augment the conductance amplitude. These findings provide evidence for the role of the loop D as a gating domain for AQP1 ion channels, and identify the likely site of interaction of AqB011 in the proximal loop D sequence.
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Affiliation(s)
- Mohamad Kourghi
- Aquaporin Physiology and Drug Discovery Program, Adelaide Medical School, University of Adelaide, Adelaide, SA, Australia
| | - Michael L De Ieso
- Aquaporin Physiology and Drug Discovery Program, Adelaide Medical School, University of Adelaide, Adelaide, SA, Australia
| | - Saeed Nourmohammadi
- Aquaporin Physiology and Drug Discovery Program, Adelaide Medical School, University of Adelaide, Adelaide, SA, Australia
| | - Jinxin V Pei
- Aquaporin Physiology and Drug Discovery Program, Adelaide Medical School, University of Adelaide, Adelaide, SA, Australia
| | - Andrea J Yool
- Aquaporin Physiology and Drug Discovery Program, Adelaide Medical School, University of Adelaide, Adelaide, SA, Australia
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Role of choroid plexus in cerebrospinal fluid hydrodynamics. Neuroscience 2017; 354:69-87. [DOI: 10.1016/j.neuroscience.2017.04.025] [Citation(s) in RCA: 75] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Revised: 04/19/2017] [Accepted: 04/19/2017] [Indexed: 12/24/2022]
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Ni ZX, Cui JM, Zhang NZ, Fu BQ. Structural and evolutionary divergence of aquaporins in parasites (Review). Mol Med Rep 2017; 15:3943-3948. [PMID: 28440467 PMCID: PMC5436202 DOI: 10.3892/mmr.2017.6505] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Accepted: 02/28/2017] [Indexed: 11/05/2022] Open
Abstract
Aquaporins are ubiquitous proteins that belong to the major intrinsic protein family. Previous studies have indicated that aquaporins are involved in multiple physiological processes in parasites, such as nutrient absorption and end product efflux, and thus, would be promising pharmacological agents in the fight against parasite infection. In the present paper, the authors analyzed the evolutionary relationship of parasitic aquaporins by re‑constructing of a phylogenic tree using neighbor‑joining and maximum likelihood methods. In addition, the authors discussed the variation of the conserved functional sites impacting on the transportation of water molecules. The protein was concluded to be a potential drug target in parasites.
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Affiliation(s)
- Zi-Xin Ni
- College of Veterinary Medicine, China Agricultural University, Beijing 100083, P.R. China
| | - Jian-Min Cui
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu 730046, P.R. China
| | - Nian-Zhang Zhang
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu 730046, P.R. China
| | - Bao-Quan Fu
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu 730046, P.R. China
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Li D, Shi X, Zhao L, Liang Z, Xie S, Wang G. Overexpression of Aquaporin 1 on cysts of patients with polycystic liver disease. REVISTA ESPANOLA DE ENFERMEDADES DIGESTIVAS 2017; 108:71-8. [PMID: 26838488 DOI: 10.17235/reed.2015.3960/2015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND AND OBJECTIVE Polycystic liver disease (PCLD) represents a group of genetic disorders that include autosomal dominant polycystic kidney disease (ADPKD) and isolated polycystic liver disease (iPCLD). There is currently no definitive treatment except for liver transplantation. The aim of this study was to assess the expression level of aquaporin 1 (AQP1) on the PCLD cysts with different sizes and provide the potential therapeutic target. METHODS We collected 3 normal bile ducts, and recruited 8 patients with simple liver cyst disease, 24 patients with ADPKD, and 17 patients with iPCLD. AQP1 expression in different types of cyst walls and in normal bile ducts was detected using real time quantitative PCR, western blot and immunofluorescence staining. We also compared AQP1 expression levels in cysts of different sizes. Besides, ionic concentrations, pH and osmolality of cyst fluid were analyzed. RESULTS The results showed that AQP1 expression in PCLD cysts was significantly higher than that in simple liver cysts and the normal bile ducts. In addition, a comparable increasing trend was found in cysts of smaller sizes to cysts of larger sizes. pH values, the sodium and chloride concentrations were higher in cyst fluid than that in the serum. CONCLUSIONS AQP1 was overexpressed in cystic cholangiocytes. A tendency of increased AQP1 protein expression in correlation with the cyst size was also found. These observations offered a direction into the molecular mechanisms of cyst expansion and maybe provide new treatment strategies to reduce fluid secretion into liver cysts.
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Affiliation(s)
- Dingyang Li
- Department of Hepatobiliary and Pancreatic Surgery, the First Norman Bethune Hospital Affiliated to J, China
| | - Xiaoju Shi
- Department of Hepatobiliary and Pancreatic Surgery, the First Norman Bethune Hospital Affiliated to J, China
| | - Lijing Zhao
- Prostate Diseases Prevention and Treatment Researc, the First Norman Bethune Hospital Affiliated to J, China
| | - Zuowen Liang
- Andrology Laboratory, the First Norman Bethune Hospital Affiliated to J, China
| | - Shuli Xie
- Department of Hepatobiliary and Pancreatic Surgery, the First Norman Bethune Hospital Affiliated to J, China
| | - Guangyi Wang
- Department of Hepatobiliary and Pancreatic Surgery, the First Norman Bethune Hospital Affiliated to J, China
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Tomita Y, Dorward H, Yool AJ, Smith E, Townsend AR, Price TJ, Hardingham JE. Role of Aquaporin 1 Signalling in Cancer Development and Progression. Int J Mol Sci 2017; 18:ijms18020299. [PMID: 28146084 PMCID: PMC5343835 DOI: 10.3390/ijms18020299] [Citation(s) in RCA: 75] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Revised: 01/19/2017] [Accepted: 01/23/2017] [Indexed: 02/07/2023] Open
Abstract
Cancer is a major health burden worldwide. Despite the advances in our understanding of its pathogenesis and continued improvement in cancer management and outcomes, there remains a strong clinical demand for more accurate and reliable biomarkers of metastatic progression and novel therapeutic targets to abrogate angiogenesis and tumour progression. Aquaporin 1 (AQP1) is a small hydrophobic integral transmembrane protein with a predominant role in trans-cellular water transport. Recently, over-expression of AQP1 has been associated with many types of cancer as a distinctive clinical prognostic factor. This has prompted researchers to evaluate the link between AQP1 and cancer biological functions. Available literature implicates the role of AQP1 in tumour cell migration, invasion and angiogenesis. This article reviews the current understanding of AQP1-facilitated tumour development and progression with a focus on regulatory mechanisms and downstream signalling pathways.
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Affiliation(s)
- Yoko Tomita
- Molecular Oncology, Basil Hetzel Institute, The Queen Elizabeth Hospital & Discipline of Physiology, School of Medicine, University of Adelaide, Adelaide, SA 5000, Australia.
| | - Hilary Dorward
- Molecular Oncology, Basil Hetzel Institute, The Queen Elizabeth Hospital, Woodville South, SA 5011, Australia.
| | - Andrea J Yool
- Discipline of Physiology, School of Medicine, University of Adelaide, Adelaide, SA 5000, Australia.
| | - Eric Smith
- Molecular Oncology, Basil Hetzel Institute, The Queen Elizabeth Hospital, Woodville South, SA 5011, Australia.
| | - Amanda R Townsend
- Medical Oncology, The Queen Elizabeth Hospital & School of Medicine, University of Adelaide, Adelaide, SA 5000, Australia.
| | - Timothy J Price
- Medical Oncology, The Queen Elizabeth Hospital & School of Medicine, University of Adelaide, Adelaide, SA 5000, Australia.
| | - Jennifer E Hardingham
- Molecular Oncology, Basil Hetzel Institute, The Queen Elizabeth Hospital & Discipline of Physiology, School of Medicine, University of Adelaide, Adelaide, SA 5000, Australia.
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Abstract
Aquaporins (AQPs ) are a family of membrane water channels that basically function as regulators of intracellular and intercellular water flow. To date, thirteen AQPs , which are distributed widely in specific cell types in various organs and tissues, have been characterized in humans. Four AQP monomers, each of which consists of six membrane-spanning alpha-helices that have a central water-transporting pore, assemble to form tetramers, forming the functional units in the membrane. AQP facilitates osmotic water transport across plasma membranes and thus transcellular fluid movement. The cellular functions of aquaporins are regulated by posttranslational modifications , e.g. phosphorylation, ubiquitination, glycosylation, subcellular distribution, degradation, and protein interactions. Insight into the molecular mechanisms responsible for regulated aquaporin trafficking and synthesis is proving to be fundamental for development of novel therapeutic targets or reliable diagnostic and prognostic biomarkers.
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Affiliation(s)
- Chunling Li
- Institute of Hypertension, Zhongshan School of Medicine, Sun Yat-sen University, 74# Zhongshan Er Road, Guangzhou, 510080, China
| | - Weidong Wang
- Institute of Hypertension, Zhongshan School of Medicine, Sun Yat-sen University, 74# Zhongshan Er Road, Guangzhou, 510080, China.
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Nuclear Receptor Regulation of Aquaporin-2 in the Kidney. Int J Mol Sci 2016; 17:ijms17071105. [PMID: 27409611 PMCID: PMC4964481 DOI: 10.3390/ijms17071105] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Revised: 07/04/2016] [Accepted: 07/04/2016] [Indexed: 01/07/2023] Open
Abstract
Aquaporin-2 (AQP2) is a vasopressin-regulated water channel responsible for regulating water reabsorption through the apical plasma membrane of the principal cells of renal collecting ducts. It has been found that dysregulation and dysfunction of AQP2 cause many disorders related to water balance in people and animals, including polyuria and dilutional hyponatremia. Classically, AQP2 mRNA and protein expression and its membrane translocation are regulated by systemic vasopressin involving short-term regulation of AQP2 trafficking to and from the apical plasma membrane and long-term regulation of the total amount of the AQP2 protein in the cell. Recently, increasing evidence has demonstrated that collecting duct AQP2 expression and membrane translocation are also under the control of many other local factors, especially nuclear receptors. Here, we briefly review the progress of studies in this area and discuss the role of nuclear receptors in the regulation of water reabsorption via affecting AQP2 expression and function.
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Fragment Screening of Human Aquaporin 1. Int J Mol Sci 2016; 17:449. [PMID: 27023529 PMCID: PMC4848905 DOI: 10.3390/ijms17040449] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Revised: 03/14/2016] [Accepted: 03/18/2016] [Indexed: 11/17/2022] Open
Abstract
Aquaporins (AQPs) are membrane proteins that enable water transport across cellular plasma membranes in response to osmotic gradients. Phenotypic analyses have revealed important physiological roles for AQPs, and the potential for AQP water channel modulators in various disease states has been proposed. For example, AQP1 is overexpressed in tumor microvessels, and this correlates with higher metastatic potential and aggressiveness of the malignancy. Chemical modulators would help in identifying the precise contribution of water channel activity in these disease states. These inhibitors would also be important therapeutically, e.g., in anti-cancer treatment. This perceived importance contrasts with the lack of success of high-throughput screens (HTS) to identify effective and specific inhibitors of aquaporins. In this paper, we have screened a library of 1500 "fragments", i.e., smaller than molecules used in HTS, against human aquaporin (hAQP1) using a thermal shift assay and surface plasmon resonance. Although these fragments may not inhibit their protein target, they bound to and stabilized hAQP1 (sub mM binding affinities (KD), with an temperature of aggregation shift ΔTagg of +4 to +50 °C) in a concentration-dependent fashion. Chemically expanded versions of these fragments should follow the determination of their binding site on the aquaporin surface.
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Nakada T. The Molecular Mechanisms of Neural Flow Coupling: A New Concept. J Neuroimaging 2015; 25:861-5. [PMID: 25704766 PMCID: PMC5023998 DOI: 10.1111/jon.12219] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2014] [Accepted: 12/10/2014] [Indexed: 11/29/2022] Open
Abstract
The phenomenon known as neural flow coupling (NFC) occurs at the capillary level where there are no known pressure controlling structures. Recent developments in advanced magnetic resonance imaging technologies have made possible in vivo direct investigations of water physiology that have shed new insight on the water dynamics of the cortical pericapillary space and their complex functionality in relation to NFC. Neural activities initiate a chain of events that ultimately affect NFC. First, neural activities generate extracellular acidification. Extracellular acidosis in turn produces inhibition of aquaporin-4 (AQP-4) located at the end feet of pericapillary astrocytes, the water channel which regulates water influx into the pericapillary space and, hence, interstitial flow. Reduction of pericapillary water pressure results in a negative balance between pericapillary and intraluminal capillary pressure, allowing for capillary caliber expansion. Proton permeability through the tight junctions of the blood brain barrier is significantly high owing to the Grotthuss proton "tunneling" mechanism and, therefore, carbonic anhydrase (CA) type IV (CA-IV) anchored to the luminal surface of brain capillaries functions as scavenger of extracellular protons. CA-IV inhibition by acetazolamide or carbon dioxide results in the accumulation of extracellular protons, causing AQP-4 inhibition and a secondary increase in rCBF.
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Affiliation(s)
- Tsutomu Nakada
- Center for Integrated Human Brain Science, Brain Research InstituteUniversity of NiigataNiigataJapan
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Kreida S, Törnroth-Horsefield S. Structural insights into aquaporin selectivity and regulation. Curr Opin Struct Biol 2015; 33:126-34. [PMID: 26342685 DOI: 10.1016/j.sbi.2015.08.004] [Citation(s) in RCA: 82] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Revised: 08/05/2015] [Accepted: 08/07/2015] [Indexed: 11/26/2022]
Abstract
Aquaporins have emerged as one of the structurally best-characterized membrane protein families, with fourteen different structures available from a diverse range of organisms. While all aquaporins share the same fold and passive mechanism for water permeation, structural details allow for differences in selectivity and modes of regulation. These details are now the emphasis of aquaporin structural biology. Recent structural studies of eukaryotic aquaporins have revealed reoccurring structural themes in both gating and trafficking, implying a limited number of structural solutions to aquaporin regulation. Moreover, the groundbreaking subangstrom resolution structure of a yeast aquaporin allows hydrogens to be visualized in the water-conducting channel, providing exclusive new insights into the proton exclusion mechanism.
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Affiliation(s)
- Stefan Kreida
- Department of Biochemistry and Structural Biology, Centre for Protein Molecular Science, Lund University, Lund, Sweden
| | - Susanna Törnroth-Horsefield
- Department of Biochemistry and Structural Biology, Centre for Protein Molecular Science, Lund University, Lund, Sweden.
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Beitz E, Golldack A, Rothert M, von Bülow J. Challenges and achievements in the therapeutic modulation of aquaporin functionality. Pharmacol Ther 2015; 155:22-35. [PMID: 26277280 DOI: 10.1016/j.pharmthera.2015.08.002] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Aquaporin (AQP) water and solute channels have basic physiological functions throughout the human body. AQP-facilitated water permeability across cell membranes is required for rapid reabsorption of water from pre-urine in the kidneys and for sustained near isosmolar water fluxes e.g. in the brain, eyes, inner ear, and lungs. Cellular water permeability is further connected to cell motility. AQPs of the aquaglyceroporin subfamily are necessary for lipid degradation in adipocytes and glycerol uptake into the liver, as well as for skin moistening. Modulation of AQP function is desirable in several pathophysiological situations, such as nephrogenic diabetes insipidus, Sjögren's syndrome, Menière's disease, heart failure, or tumors to name a few. Attempts to design or to find effective small molecule AQP inhibitors have yielded only a few hits. Challenges reside in the high copy number of AQP proteins in the cell membranes, and spatial restrictions in the protein structure. This review gives an overview on selected physiological and pathophysiological conditions in which modulation of AQP functions appears beneficial and discusses first achievements in the search of drug-like AQP inhibitors.
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Affiliation(s)
- Eric Beitz
- Pharmaceutical and Medicinal Chemistry, University of Kiel, Germany.
| | - André Golldack
- Pharmaceutical and Medicinal Chemistry, University of Kiel, Germany
| | - Monja Rothert
- Pharmaceutical and Medicinal Chemistry, University of Kiel, Germany
| | - Julia von Bülow
- Pharmaceutical and Medicinal Chemistry, University of Kiel, Germany
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Suzuki Y, Nakamura Y, Yamada K, Igarashi H, Kasuga K, Yokoyama Y, Ikeuchi T, Nishizawa M, Kwee IL, Nakada T. Reduced CSF Water Influx in Alzheimer's Disease Supporting the β-Amyloid Clearance Hypothesis. PLoS One 2015; 10:e0123708. [PMID: 25946191 PMCID: PMC4422624 DOI: 10.1371/journal.pone.0123708] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2014] [Accepted: 03/05/2015] [Indexed: 11/19/2022] Open
Abstract
OBJECTIVE To investigate whether water influx into cerebrospinal fluid (CSF) space is reduced in Alzheimer's patients as previously shown in the transgenic mouse model for Alzheimer's disease. METHODS Ten normal young volunteers (young control, 21-30 years old), ten normal senior volunteers (senior control, 60-78 years old, MMSE ≥ 29), and ten Alzheimer's disease (AD) patients (study group, 59-84 years old, MMSE: 13-19) participated in this study. All AD patients were diagnosed by neurologists specializing in dementia based on DSM-IV criteria. CSF dynamics were analyzed using positron emission tomography (PET) following an intravenous injection of 1,000 MBq [15O]H2O synthesized on-line. RESULTS Water influx into CSF space in AD patients, expressed as influx ratio, (0.755 ± 0.089) was significantly reduced compared to young controls (1.357 ± 0.185; p < 0.001) and also compared to normal senior controls (0.981 ± 0.253, p < 0.05). Influx ratio in normal senior controls was significantly reduced compared to young controls (p < 0.01). CONCLUSION Water influx into the CSF is significantly reduced in AD patients. β-amyloid clearance has been shown to be dependent on interstitial flow and CSF production. The current study indicates that reduction in water influx into the CSF may disturb the clearance rate of β-amyloid, and therefore be linked to the pathogenesis of AD. TRIAL REGISTRATION UMIN Clinical Trials Registry UMIN000011939.
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Affiliation(s)
- Yuji Suzuki
- Center for Integrated Human Brain Science, Brain Research Institute, University of Niigata, Niigata, Japan
| | - Yukihiro Nakamura
- Center for Integrated Human Brain Science, Brain Research Institute, University of Niigata, Niigata, Japan
| | - Kenichi Yamada
- Center for Integrated Human Brain Science, Brain Research Institute, University of Niigata, Niigata, Japan
| | - Hironaka Igarashi
- Center for Integrated Human Brain Science, Brain Research Institute, University of Niigata, Niigata, Japan
| | - Kensaku Kasuga
- Department of Molecular Genetics, Brain Research Institute, University of Niigata, Niigata, Japan
| | - Yuichi Yokoyama
- Department of Psychiatry, Faculty of Medicine, University of Niigata, Niigata, Japan
| | - Takeshi Ikeuchi
- Department of Molecular Genetics, Brain Research Institute, University of Niigata, Niigata, Japan
| | - Masatoyo Nishizawa
- Department of Neurology, Brain Research Institute, University of Niigata, Niigata, Japan
| | - Ingrid L. Kwee
- Department of Neurology, University of California Davis, Davis, California, United States of America
| | - Tsutomu Nakada
- Center for Integrated Human Brain Science, Brain Research Institute, University of Niigata, Niigata, Japan
- Department of Neurology, University of California Davis, Davis, California, United States of America
- * E-mail:
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Vella J, Zammit C, Di Giovanni G, Muscat R, Valentino M. The central role of aquaporins in the pathophysiology of ischemic stroke. Front Cell Neurosci 2015; 9:108. [PMID: 25904843 PMCID: PMC4389728 DOI: 10.3389/fncel.2015.00108] [Citation(s) in RCA: 84] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Accepted: 04/10/2015] [Indexed: 11/16/2022] Open
Abstract
Stroke is a complex and devastating neurological condition with limited treatment options. Brain edema is a serious complication of stroke. Early edema formation can significantly contribute to infarct formation and thus represents a promising target. Aquaporin (AQP) water channels contribute to water homeostasis by regulating water transport and are implicated in several disease pathways. At least 7 AQP subtypes have been identified in the rodent brain and the use of transgenic mice has greatly aided our understanding of their functions. AQP4, the most abundant channel in the brain, is up-regulated around the peri-infarct border in transient cerebral ischemia and AQP4 knockout mice demonstrate significantly reduced cerebral edema and improved neurological outcome. In models of vasogenic edema, brain swelling is more pronounced in AQP4-null mice than wild-type providing strong evidence of the dual role of AQP4 in the formation and resolution of both vasogenic and cytotoxic edema. AQP4 is co-localized with inwardly rectifying K(+)-channels (Kir4.1) and glial K(+) uptake is attenuated in AQP4 knockout mice compared to wild-type, indicating some form of functional interaction. AQP4-null mice also exhibit a reduction in calcium signaling, suggesting that this channel may also be involved in triggering pathological downstream signaling events. Associations with the gap junction protein Cx43 possibly recapitulate its role in edema dissipation within the astroglial syncytium. Other roles ascribed to AQP4 include facilitation of astrocyte migration, glial scar formation, modulation of inflammation and signaling functions. Treatment of ischemic cerebral edema is based on the various mechanisms in which fluid content in different brain compartments can be modified. The identification of modulators and inhibitors of AQP4 offer new therapeutic avenues in the hope of reducing the extent of morbidity and mortality in stroke.
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Affiliation(s)
| | | | | | | | - Mario Valentino
- Department of Physiology and Biochemistry, University of MaltaMsida, Malta
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Ruiz Carrillo D, To Yiu Ying J, Darwis D, Soon CH, Cornvik T, Torres J, Lescar J. Crystallization and preliminary crystallographic analysis of human aquaporin 1 at a resolution of 3.28 Å. Acta Crystallogr F Struct Biol Commun 2014; 70:1657-63. [PMID: 25484221 PMCID: PMC4259235 DOI: 10.1107/s2053230x14024558] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2014] [Accepted: 11/08/2014] [Indexed: 02/03/2023] Open
Abstract
Aquaporin water channels (AQPs) are found in almost every organism from humans to bacteria. In humans, 13 classes of AQPs control water and glycerol homeostasis. Knockout studies have suggested that modulating the activity of AQPs could be beneficial for the treatment of several pathologies. In particular, aquaporin 1 is a key factor in cell migration and angiogenesis, and constitutes a possible target for anticancer compounds and also for the treatment of glaucoma. Here, a preliminary crystallographic analysis at 3.28 Å resolution of crystals of human aquaporin 1 (hAQP1) obtained from protein expressed in Sf9 insect cells is reported. The crystals belonged to the tetragonal space group I422, with unit-cell parameters a = b = 89.28, c = 174.9 Å, and contained one monomer per asymmetric unit. The hAQP1 biological tetramer is generated via the crystallographic fourfold axis. This work extends previous electron crystallographic studies that used material extracted from human red blood cells, in which the resolution was limited to approximately 3.8 Å. It will inform efforts to improve lattice contacts and the diffraction limit for the future structure-based discovery of specific hAQP1 inhibitors.
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Affiliation(s)
- David Ruiz Carrillo
- School of Biological Sciences, Nanyang Technological University, 61 Biopolis Drive, Singapore 138673, Singapore
| | - Janet To Yiu Ying
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore
| | - Dina Darwis
- School of Biological Sciences, Nanyang Technological University, 61 Biopolis Drive, Singapore 138673, Singapore
| | - Cin Huang Soon
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore
| | - Tobias Cornvik
- School of Biological Sciences, Nanyang Technological University, 61 Biopolis Drive, Singapore 138673, Singapore
| | - Jaume Torres
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore
| | - Julien Lescar
- School of Biological Sciences, Nanyang Technological University, 61 Biopolis Drive, Singapore 138673, Singapore
- Centre d’Immunologie et des Maladies Infectieuses, Inserm U1135, Centre Hospitalier Universitaire Pitié-Salpêtrière–UPMC CR7–CNRS ERL 8255, Paris 75013, France
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Zhang H, Li H, Liu E, Guang Y, Yang L, Mao J, Zhu L, Chen L, Wang L. The AQP-3 water channel and the ClC-3 chloride channel coordinate the hypotonicity-induced swelling volume in nasopharyngeal carcinoma cells. Int J Biochem Cell Biol 2014; 57:96-107. [DOI: 10.1016/j.biocel.2014.10.014] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Revised: 10/06/2014] [Accepted: 10/08/2014] [Indexed: 11/25/2022]
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Temporal and spatial distribution of the aquaporin 1 in spinal cord and dorsal root ganglia after traumatic injuries of the sciatic nerve. Childs Nerv Syst 2014; 30:1679-86. [PMID: 25119150 DOI: 10.1007/s00381-014-2472-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/07/2014] [Accepted: 06/12/2014] [Indexed: 10/24/2022]
Abstract
PURPOSE The aquaporin family comprises a large family of integral membrane proteins that enable the movement of water and other small, neutral solutes across plasma membranes. Although function and mechanism of aquaporins in central nervous system injury have been reported, the pathophysiologic role of aquaporin 1 (AQP1) in peripheral nerve has not been extensively documented. In the present study, we aimed to study the temporal and spatial distribution of AQP1 in spinal cord and dorsal root ganglia after sciatic nerve injury. METHODS Forty-eight adult female mice were randomly divided into four groups (intact controls, sham operated, cut injury, and crush injury). Animals receiving cut or crush injuries were sacrificed at the 2nd, 24th, and 48th postoperative hours. Spinal cord samples at the level of lumbosacral intumescences and corresponding dorsal root ganglia on the experimental and contralateral side were dissected free and proceeded to AQP1 immunohistochemistry. RESULTS Our quantitative estimations revealed that a sharp increase in AQP1 immunoreactivity at the 24th postoperative hour was observed. This sharp increase was no more evident at 48 h after sciatic nerve injury. Identical peak was observed after both cut and crush injuries. CONCLUSIONS We demonstrated that there was a temporal relationship with an increased expression of AQP1 following injury sustained to the sciatic nerve that was significantly observed in dorsal root ganglia and spinal cord. Those expressions were also subsided over time.
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Papadopoulos MC, Saadoun S. Key roles of aquaporins in tumor biology. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2014; 1848:2576-83. [PMID: 25204262 DOI: 10.1016/j.bbamem.2014.09.001] [Citation(s) in RCA: 148] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2014] [Revised: 08/25/2014] [Accepted: 09/01/2014] [Indexed: 12/13/2022]
Abstract
Aquaporins are protein channels that facilitate the flow of water across plasma cell membranes in response to osmotic gradients. This review summarizes the evidence that aquaporins play key roles in tumor biology including tumor-associated edema, tumor cell migration, tumor proliferation and tumor angiogenesis. Aquaporin inhibitors may thus be a novel class of anti-tumor agents. However, attempts to produce small molecule aquaporin inhibitors have been largely unsuccessful. Recently, monoclonal human IgG antibodies against extracellular aquaporin-4 domains have become available and could be engineered to kill aquaporin-4 over-expressing cells in the malignant brain tumor glioblastoma. We conclude this review by discussing future directions in aquaporin tumor research. This article is part of a Special Issue entitled: Membrane channels and transporters in cancers.
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Affiliation(s)
| | - Samira Saadoun
- Academic Neurosurgery Unit, St. George's, University of London, London SW17 0RE, UK.
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Nakada T. Virchow-Robin space and aquaporin-4: new insights on an old friend. Croat Med J 2014; 55:328-36. [PMID: 25165047 PMCID: PMC4157385 DOI: 10.3325/cmj.2014.55.328] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Accepted: 07/09/2014] [Indexed: 11/18/2022] Open
Abstract
Recent studies have strongly indicated that the classic circulation model of cerebrospinal fluid (CSF) is no longer valid. The production of CSF is not only dependent on the choroid plexus but also on water flux in the peri-capillary (Virchow Robin) space. Historically, CSF flow through the Virchow Robin space is known as interstitial flow, the physiological significance of which is now fully understood. This article briefly reviews the modern concept of CSF physiology and the Virchow-Robin space, in particular its functionalities critical for central nervous system neural activities. Water influx into the Virchow Robin space and, hence, interstitial flow is regulated by aquaporin-4 (AQP-4) localized in the endfeet of astrocytes, connecting the intracellular cytosolic fluid space of astrocytes and the Virchow Robin space. Interstitial flow has a functionality equivalent to systemic lymphatics, on which clearance of β-amyloid is strongly dependent. Autoregulation of brain blood flow serves to maintain a constant inner capillary fluid pressure, allowing fluid pressure of the Virchow Robin space to regulate regional cerebral blood flow (rCBF) based on AQP-4 gating. Excess heat produced by neural activities is effectively removed from the area of activation by increased rCBF by closing AQP-4 channels. This neural flow coupling (NFC) is likely mediated by heat generated proton channels.
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Affiliation(s)
- Tsutomu Nakada
- Tsutomu Nakada, Center for Integrated Human Brain Science, Brain Research Institute, University of Niigata, 1-757 Asahimachi, Niigata, 951-8585, Japan,
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Yan C, Zhu Y, Zhang X, Chen X, Zheng W, Yang J. Down-regulated aquaporin 5 inhibits proliferation and migration of human epithelial ovarian cancer 3AO cells. J Ovarian Res 2014; 7:78. [PMID: 25298246 PMCID: PMC4164796 DOI: 10.1186/s13048-014-0078-2] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2014] [Accepted: 07/28/2014] [Indexed: 01/22/2023] Open
Abstract
Background Recent studies suggested that aquaporins 5 (AQP5) was associated with many kinds of cancers and regulated many processes of various kinds of cancer cells. Our previous studies also demonstrated that AQP5 was highly expressed in epithelial ovarian cancer and contributed to the progress of ovarian cancer. Methods Lentivirus for knocking-down the expression of AQP5 was prepared and verified by qPCR and Western blotting. Cell counting kit-8 (CCK8) assay and transwell assay were performed to investigate the role of AQP5 on proliferation and migration of 3AO cells. The effects of down-regulating AQP5 on tumorigenesis were tested by tumor xenografts experiments. Results An effective lentivirus silencing AQP5 expression was obtained and used in this study. Down-regulating AQP5 inhibited proliferation and migration of cultured human epithelial ovarian cancer 3AO Cell. Furthermore, interfering of AQP5 during tumorigenesis could efficiently decrease the tumor growth in athymic mice. Conclusions These findings altogether suggest that AQP5 regulated multi processes in ovarian carcinogenesis and may be an attractive therapeutic target.
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Igarashi H, Suzuki Y, Kwee IL, Nakada T. Water influx into cerebrospinal fluid is significantly reduced in senile plaque bearing transgenic mice, supporting beta-amyloid clearance hypothesis of Alzheimer's disease. Neurol Res 2014; 36:1094-8. [PMID: 25082552 PMCID: PMC4188033 DOI: 10.1179/1743132814y.0000000434] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
Recent studies on cerebrospinal fluid (CSF) homeostasis emphasize the importance of water influx into the peri-capillary (Virchow-Robin) space through aquaporin 4 (AQP-4). This water flow is believed to have the functionality equivalent to the systemic lymphatic system and plays a critical role in beta-amyloid clearance. Using a newly developed molecular imaging technique capable of tracing water molecules, in vivo, water influx into the CSF was quantitatively analyzed in senile plaque (SP) bearing transgenic Alzheimer's disease (AD) model mice. The results unequivocally demonstrated that water influx into CSF is significantly impaired in SP-bearing transgenic mice, the degree of which being virtually identical to that previously observed in AQP-4 knockout mice. The study strongly indicates that disturbance in AQP-4-based water flow and, hence, impairment in beta-amyloid clearance play a significant role in SP formation.
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Affiliation(s)
- Hironaka Igarashi
- Center for Integrated Human Brain Science, Brain Research Institute, University of Niigata, Chuo-ku, Niigata, Japan
| | - Yuji Suzuki
- Center for Integrated Human Brain Science, Brain Research Institute, University of Niigata, Chuo-ku, Niigata, Japan
| | - Ingrid L Kwee
- Department of Neurology, University of California, Davis, Martinez, CA, USA
| | - Tsutomu Nakada
- Center for Integrated Human Brain Science, Brain Research Institute, University of Niigata, Chuo-ku, Niigata, Japan
- Department of Neurology, University of California, Davis, Martinez, CA, USA
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Water influx into cerebrospinal fluid is primarily controlled by aquaporin-4, not by aquaporin-1: 17O JJVCPE MRI study in knockout mice. Neuroreport 2014; 25:39-43. [PMID: 24231830 PMCID: PMC4235386 DOI: 10.1097/wnr.0000000000000042] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Recent studies on cerebrospinal fluid (CSF) homeostasis emphasize the importance of water flux through the pericapillary (Virchow-Robin) space for both CSF production and reabsorption (Oreskovic and Klarica hypothesis), and challenge the classic CSF circulation theory, which proposes that CSF is primarily produced by the choroid plexus and reabsorbed by the arachnoid villi. Active suppression of aquaporin-1 (AQP-1) expression within brain capillaries and preservation of AQP-1 within the choroid plexus together with pericapillary water regulation by AQP-4 provide a unique opportunity for testing this recent hypothesis. We investigated water flux into three representative regions of the brain, namely, the cortex, basal ganglia, and third ventricle using a newly developed water molecular MRI technique based on JJ vicinal coupling between O and adjacent protons and water molecule proton exchanges (JJVCPE imaging) in AQP-1 and AQP-4 knockout mice in vivo. The results clearly indicate that water influx into the CSF is regulated by AQP-4, and not by AQP-1, strongly supporting the Oreskovic and Klarica hypothesis.
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Abstract
Cerebral oedema (CO) after brain injury can occur from different ways. The vasogenic and cytotoxic oedema are usually described but osmotic and hydrostatic CO, respectively secondary to plasmatic hypotonia or increase in blood pressure, can also be encountered. Addition of these several mechanisms can worsen injuries. Consequences are major, leading quickly to death secondary to intracerebral hypertension and later to neuropsychic sequelae. So therapeutic care to control this phenomenon is essential and osmotherapy is actually the only way. A better understanding of physiopathological disorders, particularly energetic ways (lactate), aquaporine function, inflammation lead to new therapeutic hopes. The promising experimental results need now to be confirmed by clinical data.
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de Almeida A, Soveral G, Casini A. Gold compounds as aquaporin inhibitors: new opportunities for therapy and imaging. MEDCHEMCOMM 2014. [DOI: 10.1039/c4md00265b] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A review on the development of gold-based compounds as aquaglyceroporin inhibitors with potential as therapeutic agents or as chemical probes.
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Affiliation(s)
- Andreia de Almeida
- Dept. of Pharmacokinetics, Toxicology and Targeting
- Research Institute of Pharmacy
- University of Groningen
- 9713 AV Groningen, The Netherlands
| | - Graça Soveral
- Instituto de Investigação do Medicamento (iMed.ULisboa)
- Faculdade de Farmácia
- Universidade de Lisboa Av. Prof Gama Pinto
- 1649-003 Lisbon, Portugal
| | - Angela Casini
- Dept. of Pharmacokinetics, Toxicology and Targeting
- Research Institute of Pharmacy
- University of Groningen
- 9713 AV Groningen, The Netherlands
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Abstract
Aquaporins (AQPs) are a family of membrane water channels that basically function as regulators of intracellular and intercellular water flow. To date, thirteen aquaporins have been characterized. They are distributed wildly in specific cell types in multiple organs and tissues. Each AQP channel consists of six membrane-spanning alpha-helices that have a central water-transporting pore. Four AQP monomers assemble to form tetramers, which are the functional units in the membrane. Some of AQPs also transport urea, glycerol, ammonia, hydrogen peroxide, and gas molecules. AQP-mediated osmotic water transport across epithelial plasma membranes facilitates transcellular fluid transport and thus water reabsorption. AQP-mediated urea and glycerol transport is involved in energy metabolism and epidermal hydration. AQP-mediated CO2 and NH3 transport across membrane maintains intracellular acid-base homeostasis. AQPs are also involved in the pathophysiology of a wide range of human diseases (including water disbalance in kidney and brain, neuroinflammatory disease, obesity, and cancer). Further work is required to determine whether aquaporins are viable therapeutic targets or reliable diagnostic and prognostic biomarkers.
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Munday JC, Eze AA, Baker N, Glover L, Clucas C, Aguinaga Andrés D, Natto MJ, Teka IA, McDonald J, Lee RS, Graf FE, Ludin P, Burchmore RJS, Turner CMR, Tait A, MacLeod A, Mäser P, Barrett MP, Horn D, De Koning HP. Trypanosoma brucei aquaglyceroporin 2 is a high-affinity transporter for pentamidine and melaminophenyl arsenic drugs and the main genetic determinant of resistance to these drugs. J Antimicrob Chemother 2013; 69:651-63. [PMID: 24235095 PMCID: PMC3922157 DOI: 10.1093/jac/dkt442] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Objectives Trypanosoma brucei drug transporters include the TbAT1/P2 aminopurine transporter and the high-affinity pentamidine transporter (HAPT1), but the genetic identity of HAPT1 is unknown. We recently reported that loss of T. brucei aquaglyceroporin 2 (TbAQP2) caused melarsoprol/pentamidine cross-resistance (MPXR) in these parasites and the current study aims to delineate the mechanism by which this occurs. Methods The TbAQP2 loci of isogenic pairs of drug-susceptible and MPXR strains of T. brucei subspecies were sequenced. Drug susceptibility profiles of trypanosome strains were correlated with expression of mutated TbAQP2 alleles. Pentamidine transport was studied in T. brucei subspecies expressing TbAQP2 variants. Results All MPXR strains examined contained TbAQP2 deletions or rearrangements, regardless of whether the strains were originally adapted in vitro or in vivo to arsenicals or to pentamidine. The MPXR strains and AQP2 knockout strains had lost HAPT1 activity. Reintroduction of TbAQP2 in MPXR trypanosomes restored susceptibility to the drugs and reinstated HAPT1 activity, but did not change the activity of TbAT1/P2. Expression of TbAQP2 sensitized Leishmania mexicana promastigotes 40-fold to pentamidine and >1000-fold to melaminophenyl arsenicals and induced a high-affinity pentamidine transport activity indistinguishable from HAPT1 by Km and inhibitor profile. Grafting the TbAQP2 selectivity filter amino acid residues onto a chimeric allele of AQP2 and AQP3 partly restored susceptibility to pentamidine and an arsenical. Conclusions TbAQP2 mediates high-affinity uptake of pentamidine and melaminophenyl arsenicals in trypanosomes and TbAQP2 encodes the previously reported HAPT1 activity. This finding establishes TbAQP2 as an important drug transporter.
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Affiliation(s)
- Jane C Munday
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
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Schey KL, Wang Z, L Wenke J, Qi Y. Aquaporins in the eye: expression, function, and roles in ocular disease. Biochim Biophys Acta Gen Subj 2013; 1840:1513-23. [PMID: 24184915 DOI: 10.1016/j.bbagen.2013.10.037] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2013] [Revised: 10/22/2013] [Accepted: 10/23/2013] [Indexed: 12/13/2022]
Abstract
BACKGROUND All thirteen known mammalian aquaporins have been detected in the eye. Moreover, aquaporins have been identified as playing essential roles in ocular functions ranging from maintenance of lens and corneal transparency to production of aqueous humor to maintenance of cellular homeostasis and regulation of signal transduction in the retina. SCOPE OF REVIEW This review summarizes the expression and known functions of ocular aquaporins and discusses their known and potential roles in ocular diseases. MAJOR CONCLUSIONS Aquaporins play essential roles in all ocular tissues. Remarkably, not all aquaporin function as a water permeable channel and the functions of many aquaporins in ocular tissues remain unknown. Given their vital roles in maintaining ocular function and their roles in disease, aquaporins represent potential targets for future therapeutic development. GENERAL SIGNIFICANCE Since aquaporins play key roles in ocular physiology, an understanding of these functions is important to improving ocular health and treating diseases of the eye. It is likely that future therapies for ocular diseases will rely on modulation of aquaporin expression and/or function. This article is part of a Special Issue entitled Aquaporins.
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Affiliation(s)
- Kevin L Schey
- Department of Biochemistry, Vanderbilt School of Medicine, Vanderbilt University, Nashville, TN 37232, USA.
| | - Zhen Wang
- Department of Biochemistry, Vanderbilt School of Medicine, Vanderbilt University, Nashville, TN 37232, USA
| | - Jamie L Wenke
- Department of Biochemistry, Vanderbilt School of Medicine, Vanderbilt University, Nashville, TN 37232, USA
| | - Ying Qi
- Department of Biochemistry, Vanderbilt School of Medicine, Vanderbilt University, Nashville, TN 37232, USA
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Prognostic value of combined aquaporin 3 and aquaporin 5 overexpression in hepatocellular carcinoma. BIOMED RESEARCH INTERNATIONAL 2013; 2013:206525. [PMID: 24224160 PMCID: PMC3810059 DOI: 10.1155/2013/206525] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/11/2013] [Revised: 08/29/2013] [Accepted: 09/02/2013] [Indexed: 12/12/2022]
Abstract
Background. Aquaporin (AQP) 3 and AQP 5 are involved in tumorigenesis and tumor progression of several tumor types. Aim. To investigate expression patterns and clinical significance of AQP3 and AQP5 in hepatocellular carcinoma (HCC). Methods. Immunohistochemistry was performed to detect the expression of AQP3 and AQP5 in HCC tissues. Results. Immunohistochemistry analysis showed the increased expression of AQP3 and AQP5 protein levels in HCC tissues compared with their adjacent nonneoplastic tissues (both P < 0.001). In addition, combined AQP3 and AQP5 protein expression was significantly associated with serum AFP (P = 0.008), tumor stage (P = 0.006), and tumor grade (P = 0.006). Moreover, HCC patients highly expressing both AQP3 and AQP5 proteins had worse 5-year disease-free survival and 5-year overall survival (P = 0.002 and 0.005, resp.). Furthermore, the Cox proportional hazards model showed that combined AQP3 and AQP5 protein expression was an independent poor prognostic factor for both 5-year disease-free survival (P = 0.009) and 5-year overall survival (P = 0.01) in HCC. Conclusion. Our data suggest for the first time that the aberrant expression of AQP3 and AQP5 proteins may be strongly related to tumor progression and prognosis in patients with HCC. The overexpression of AQP3 in combination with upregulation of AQP5 may be an unfavorable prognostic factor for HCC.
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Liu S, Zhang S, Jiang H, Yang Y, Jiang Y. Co-expression of AQP3 and AQP5 in esophageal squamous cell carcinoma correlates with aggressive tumor progression and poor prognosis. Med Oncol 2013; 30:636. [DOI: 10.1007/s12032-013-0636-2] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2013] [Accepted: 06/10/2013] [Indexed: 11/27/2022]
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