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Elekes G, Csapó V, Szarka D, Szalay L, Korsós MM, Tálosi D, Török D, Tóth-Molnár E. The Role of Aquaporin 4 in Lacrimal Gland Ductal Fluid Secretion in Mice. Invest Ophthalmol Vis Sci 2024; 65:30. [PMID: 38771571 PMCID: PMC11114615 DOI: 10.1167/iovs.65.5.30] [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: 12/12/2023] [Accepted: 05/04/2024] [Indexed: 05/22/2024] Open
Abstract
Purpose Earlier reports highlighted the predominant presence of aquaporin 4 (AQP4) in the duct cells of rabbit lacrimal glands (LGs). Whereas significant alterations in AQP4 mRNA levels have been observed in experimental dry eye and during pregnancy, the impact of AQP4 in LG ductal fluid production remains unclear. In our recent work, the role of AQP4 in LG ductal fluid secretion was investigated utilizing wild type (WT) and AQP4 knock out (KO) mice. Methods Tear production was assessed in both WT and KO animals. Immunostaining was used to identify AQP4 protein. Duct segments were harvested from LGs of WT and KO mice. Fluid secretion and filtration permeability (Pf) were quantified using video-microscopy. Ductal tear production, elicited by a cell-permeable cAMP analogue (8-bromo cAMP), carbachol, vasoactive intestinal peptide (VIP), and phenylephrine (PHE), were assessed in both WT and KO ducts. Results A higher expression of AQP4 protein was noted in the duct cells from WT mice when compared to acinar cells. Pf did not show notable alterations between WT and AQP4 KO ducts. Carbachol elicited comparable secretory responses in ducts from both WT and KO animals. However, 8-bromo cAMP, VIP, and PHE stimulation resulted in decreased secretion in ducts from AQP4 KO LGs. Conclusions Our findings underscore the functional relevance of AQP4 in the fluid production of mouse LG ducts. AQP4 seems to play different roles in fluid secretions elicited by different secretagogues. Specifically, cAMP-mediated, and adrenergic agonist-related secretions were reduced in AQP4 KO ducts.
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Affiliation(s)
- Gréta Elekes
- Department of Ophthalmology, University of Szeged, Szeged, Hungary
| | - Virág Csapó
- Department of Ophthalmology, University of Szeged, Szeged, Hungary
| | - Dóra Szarka
- Department of Ophthalmology, University of Szeged, Szeged, Hungary
| | - László Szalay
- Department of Ophthalmology, University of Szeged, Szeged, Hungary
| | | | - Dorottya Tálosi
- Albert Szent-Gyorgyi Medical School, University of Szeged, Szeged, Hungary
| | - Dénes Török
- Department of Anatomy, University of Szeged, Szeged, Hungary
| | - Edit Tóth-Molnár
- Department of Ophthalmology, University of Szeged, Szeged, Hungary
- Faculty of Health Sciences and Social Studies, University of Szeged, Szeged, Hungary
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The Water Transport System in Astrocytes–Aquaporins. Cells 2022; 11:cells11162564. [PMID: 36010640 PMCID: PMC9406552 DOI: 10.3390/cells11162564] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2022] [Revised: 07/26/2022] [Accepted: 08/08/2022] [Indexed: 11/16/2022] Open
Abstract
Highlights (AQPs) are transmembrane proteins responsible for fast water movement across cell membranes, including those of astrocytes. The expression and subcellular localization of AQPs in astrocytes are highly dynamic under physiological and pathological conditions. Besides their primary function in water homeostasis, AQPs participate in many ancillary functions including glutamate clearance in tripartite synapses and cell migration.
Abstract Astrocytes have distinctive morphological and functional characteristics, and are found throughout the central nervous system. Astrocytes are now known to be far more than just housekeeping cells in the brain. Their functions include contributing to the formation of the blood–brain barrier, physically and metabolically supporting and communicating with neurons, regulating the formation and functions of synapses, and maintaining water homeostasis and the microenvironment in the brain. Aquaporins (AQPs) are transmembrane proteins responsible for fast water movement across cell membranes. Various subtypes of AQPs (AQP1, AQP3, AQP4, AQP5, AQP8 and AQP9) have been reported to be expressed in astrocytes, and the expressions and subcellular localizations of AQPs in astrocytes are highly correlated with both their physiological and pathophysiological functions. This review describes and summarizes the recent advances in our understanding of astrocytes and AQPs in regard to controlling water homeostasis in the brain. Findings regarding the features of different AQP subtypes, such as their expression, subcellular localization, physiological functions, and the pathophysiological roles of astrocytes are presented, with brain edema and glioma serving as two representative AQP-associated pathological conditions. The aim is to provide a better insight into the elaborate “water distribution” system in cells, exemplified by astrocytes, under normal and pathological conditions.
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Chen Y, Chen H, Wang C, Yu J, Tao J, Mao J, Shen L. The Correlation between the Increased Expression of Aquaporins on the Inner Limiting Membrane and the Occurrence of Diabetic Macular Edema. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2022; 2022:7412208. [PMID: 35528520 PMCID: PMC9071982 DOI: 10.1155/2022/7412208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Revised: 03/23/2022] [Accepted: 04/01/2022] [Indexed: 11/18/2022]
Abstract
Purpose Diabetic macular edema (DME) is a major cause of vision loss in patients with diabetic retinopathy; this study is aimed at comparing the expression of aquaporins (AQPs) on the inner limiting membranes (ILMs) of various vitreoretinal diseases and investigating the role of aquaporins expressed on the ILMs in mediating the occurrence of DME. Methods The whole-mounted ILM specimens surgically excised from patients with various vitreoretinal diseases (idiopathic macular hole, myopic traction maculopathy, and diabetic retinopathy) were analyzed by immunohistochemistry (IHC). The distribution and morphology of AQP4, AQP7, and AQP11 on the ILMs were correlated with immunohistochemical staining characteristics. Moreover, immunofluorescence of AQP4 was performed on the ILM specimens of the patient in four groups: the control group, negative control group, no DME group, and DME group. The immunofluorescence intensity value of AQP4 was measured using ImageJ. The difference between the four groups and the correction between the immunofluorescence value and central foveal thickness (CFT) were analyzed. Results In IHC sections, the expression of AQP4, AQP7, and AQP11 on ILMs of diabetic retinopathy (DR) with macular edema, respectively, seemed to be more abundant than in the idiopathic macular hole (iMH) and myopic traction maculopathy (MTM). Moreover, markedly higher fluorescence intensity of AQP4 of ILMs was determined in the DME group (51.05 ± 5.67) versus the other three groups (P < 0.001). A marked positive association was identified between the fluorescence intensity of AQP4 and CFT (r = 0.758; P = 0.011). Conclusions AQP4, AQP7, and AQP11 can be expressed on human ILM in vivo. The increased expression of AQPs on the ILMs of DR may be associated with the occurrence of DME. Moreover, the degree of DME may be positively correlated with the expression of AQP4 on the ILMs.
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Affiliation(s)
- Yiqi Chen
- Center for Rehabilitation Medicine, Department of Ophthalmology, Zhejiang Provincial People's Hospital (Affiliated People's Hospital, Hangzhou Medical College), Hangzhou, Zhejiang, China
| | - Huan Chen
- Department of Retina Center, Affiliated Eye Hospital of Wenzhou Medical University, Hangzhou, 310000 Zhejiang Province, China
| | - Chenxi Wang
- Center for Rehabilitation Medicine, Department of Ophthalmology, Zhejiang Provincial People's Hospital (Affiliated People's Hospital, Hangzhou Medical College), Hangzhou, Zhejiang, China
| | - Jiafeng Yu
- Center for Rehabilitation Medicine, Department of Ophthalmology, Zhejiang Provincial People's Hospital (Affiliated People's Hospital, Hangzhou Medical College), Hangzhou, Zhejiang, China
| | - Jiwei Tao
- Department of Retina Center, Affiliated Eye Hospital of Wenzhou Medical University, Hangzhou, 310000 Zhejiang Province, China
| | - Jianbo Mao
- Center for Rehabilitation Medicine, Department of Ophthalmology, Zhejiang Provincial People's Hospital (Affiliated People's Hospital, Hangzhou Medical College), Hangzhou, Zhejiang, China
| | - Lijun Shen
- Center for Rehabilitation Medicine, Department of Ophthalmology, Zhejiang Provincial People's Hospital (Affiliated People's Hospital, Hangzhou Medical College), Hangzhou, Zhejiang, China
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Szczygielski J, Kopańska M, Wysocka A, Oertel J. Cerebral Microcirculation, Perivascular Unit, and Glymphatic System: Role of Aquaporin-4 as the Gatekeeper for Water Homeostasis. Front Neurol 2021; 12:767470. [PMID: 34966347 PMCID: PMC8710539 DOI: 10.3389/fneur.2021.767470] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Accepted: 11/12/2021] [Indexed: 12/13/2022] Open
Abstract
In the past, water homeostasis of the brain was understood as a certain quantitative equilibrium of water content between intravascular, interstitial, and intracellular spaces governed mostly by hydrostatic effects i.e., strictly by physical laws. The recent achievements in molecular bioscience have led to substantial changes in this regard. Some new concepts elaborate the idea that all compartments involved in cerebral fluid homeostasis create a functional continuum with an active and precise regulation of fluid exchange between them rather than only serving as separate fluid receptacles with mere passive diffusion mechanisms, based on hydrostatic pressure. According to these concepts, aquaporin-4 (AQP4) plays the central role in cerebral fluid homeostasis, acting as a water channel protein. The AQP4 not only enables water permeability through the blood-brain barrier but also regulates water exchange between perivascular spaces and the rest of the glymphatic system, described as pan-cerebral fluid pathway interlacing macroscopic cerebrospinal fluid (CSF) spaces with the interstitial fluid of brain tissue. With regards to this, AQP4 makes water shift strongly dependent on active processes including changes in cerebral microcirculation and autoregulation of brain vessels capacity. In this paper, the role of the AQP4 as the gatekeeper, regulating the water exchange between intracellular space, glymphatic system (including the so-called neurovascular units), and intravascular compartment is reviewed. In addition, the new concepts of brain edema as a misbalance in water homeostasis are critically appraised based on the newly described role of AQP4 for fluid permeation. Finally, the relevance of these hypotheses for clinical conditions (including brain trauma and stroke) and for both new and old therapy concepts are analyzed.
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Affiliation(s)
- Jacek Szczygielski
- Department of Neurosurgery, Institute of Medical Sciences, University of Rzeszów, Rzeszów, Poland.,Department of Neurosurgery, Faculty of Medicine and Saarland University Medical Center, Saarland University, Homburg, Germany
| | - Marta Kopańska
- Department of Pathophysiology, Institute of Medical Sciences, University of Rzeszów, Rzeszów, Poland
| | - Anna Wysocka
- Chair of Internal Medicine and Department of Internal Medicine in Nursing, Faculty of Health Sciences, Medical University of Lublin, Lublin, Poland
| | - Joachim Oertel
- Department of Neurosurgery, Faculty of Medicine and Saarland University Medical Center, Saarland University, Homburg, Germany
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Filchenko I, Blochet C, Buscemi L, Price M, Badaut J, Hirt L. Caveolin-1 Regulates Perivascular Aquaporin-4 Expression After Cerebral Ischemia. Front Cell Dev Biol 2020; 8:371. [PMID: 32523952 PMCID: PMC7261922 DOI: 10.3389/fcell.2020.00371] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Accepted: 04/27/2020] [Indexed: 01/25/2023] Open
Abstract
Edema is a hallmark of many brain disorders including stroke. During vasogenic edema, blood-brain barrier (BBB) permeability increases, contributing to the entry of plasma proteins followed by water. Caveolae and caveolin-1 (Cav-1) are involved in these BBB permeability changes. The expression of the aquaporin-4 (AQP4) water channel relates to brain swelling, however, its regulation is poorly understood. Here we tested whether Cav-1 regulates AQP4 expression in the perivascular region after brain ischemia in mice. We showed that Cav-1 knockout mice had enhanced hemispheric swelling and decreased perivascular AQP4 expression in perilesional and contralateral cortical regions compared to wild-type. Glial fibrillary acidic protein-positive astrocytes displayed less branching and ramification in Cav-1 knockout mice compared to wild-type animals. There was a positive correlation between the area of perivascular AQP4-immunolabelling and branch length of Glial fibrillary acidic protein-positive astrocytes in wild-type mice, not seen in Cav-1 knockout mice. In summary, we show for the first time that loss of Cav-1 results in decreased AQP4 expression and impaired perivascular AQP4 covering after cerebral ischemia associated with altered reactive astrocyte morphology and enhanced brain swelling. Therapeutic approaches targeting Cav-1 may provide new opportunities for improving stroke outcome.
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Affiliation(s)
- Irina Filchenko
- Service of Neurology, Department of Clinical Neurosciences, CHUV, Lausanne, Switzerland.,North-Western State Medical University named after I.I. Mechnikov, Saint-Petersburg, Russia.,Department of Fundamental Neurosciences, University of Lausanne, Lausanne, Switzerland
| | - Camille Blochet
- Service of Neurology, Department of Clinical Neurosciences, CHUV, Lausanne, Switzerland.,Department of Fundamental Neurosciences, University of Lausanne, Lausanne, Switzerland
| | - Lara Buscemi
- Service of Neurology, Department of Clinical Neurosciences, CHUV, Lausanne, Switzerland.,Department of Fundamental Neurosciences, University of Lausanne, Lausanne, Switzerland
| | - Melanie Price
- Service of Neurology, Department of Clinical Neurosciences, CHUV, Lausanne, Switzerland.,Department of Fundamental Neurosciences, University of Lausanne, Lausanne, Switzerland
| | - Jerome Badaut
- Brain Molecular Imaging Lab, CNRS UMR 5287, INCIA, University of Bordeaux, Bordeaux, France.,Basic Science Department, Loma Linda University School of Medicine, Loma Linda, CA, United States
| | - Lorenz Hirt
- Service of Neurology, Department of Clinical Neurosciences, CHUV, Lausanne, Switzerland.,Department of Fundamental Neurosciences, University of Lausanne, Lausanne, Switzerland
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Shivaraj SM, Vats S, Bhat JA, Dhakte P, Goyal V, Khatri P, Kumawat S, Singh A, Prasad M, Sonah H, Sharma TR, Deshmukh R. Nitric oxide and hydrogen sulfide crosstalk during heavy metal stress in plants. PHYSIOLOGIA PLANTARUM 2020; 168:437-455. [PMID: 31587278 DOI: 10.1111/ppl.13028] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2019] [Revised: 09/10/2019] [Accepted: 09/23/2019] [Indexed: 06/10/2023]
Abstract
Gases such as ethylene, hydrogen peroxide (H2 O2 ), nitric oxide (NO), carbon monoxide (CO) and hydrogen sulfide (H2 S) have been recognized as vital signaling molecules in plants and animals. Of these gasotransmitters, NO and H2 S have recently gained momentum mainly because of their involvement in numerous cellular processes. It is therefore important to study their various attributes including their biosynthetic and signaling pathways. The present review provides an insight into various routes for the biosynthesis of NO and H2 S as well as their signaling role in plant cells under different conditions, more particularly under heavy metal stress. Their beneficial roles in the plant's protection against abiotic and biotic stresses as well as their adverse effects have been addressed. This review describes how H2 S and NO, being very small-sized molecules, can quickly pass through the cell membranes and trigger a multitude of responses to various factors, notably to various stress conditions such as drought, heat, osmotic, heavy metal and multiple biotic stresses. The versatile interactions between H2 S and NO involved in the different molecular pathways have been discussed. In addition to the signaling role of H2 S and NO, their direct role in posttranslational modifications is also considered. The information provided here will be helpful to better understand the multifaceted roles of H2 S and NO in plants, particularly under stress conditions.
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Affiliation(s)
- Sheelavanta M Shivaraj
- Département de phytologie, University Laval, Quebec City, QC, Canada
- National Institute for Plant Biotechnology, New Delhi, India
| | - Sanskriti Vats
- National Agri-Food Biotechnology Institute, Mohali, India
| | - Javaid A Bhat
- Soybean Research Institution, Nanjing Agricultural University, Jiangsu Sheng, China
| | - Priyanka Dhakte
- National Institute of Plant Genome Research, New Delhi, India
| | - Vinod Goyal
- Department of Botany and Plant Physiology, Chaudhary Charan Singh Haryana Agricultural University, Haryana, India
| | - Praveen Khatri
- National Agri-Food Biotechnology Institute, Mohali, India
| | - Surbhi Kumawat
- National Agri-Food Biotechnology Institute, Mohali, India
| | - Akshay Singh
- National Agri-Food Biotechnology Institute, Mohali, India
| | - Manoj Prasad
- National Institute of Plant Genome Research, New Delhi, India
| | - Humira Sonah
- National Agri-Food Biotechnology Institute, Mohali, India
| | - Tilak R Sharma
- National Agri-Food Biotechnology Institute, Mohali, India
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Chu H, Yang X, Huang C, Gao Z, Tang Y, Dong Q. Apelin-13 Protects against Ischemic Blood-Brain Barrier Damage through the Effects of Aquaporin-4. Cerebrovasc Dis 2017; 44:10-25. [PMID: 28402976 DOI: 10.1159/000460261] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2016] [Accepted: 01/30/2017] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND Apelin-13 has been found to have protective effects on many neurological diseases, including cerebral ischemia. However, whether Apelin-13 acts on blood-brain barrier (BBB) disruption following cerebral ischemia is largely unknown. Aquaporin-4 (AQP4) has a close link with BBB due to the high concentration in astrocyte foot processes and regulation of astrocytes function. Here, we aimed to test Apelin-13's effects on ischemic BBB injury and examine whether the effects were dependent on AQP4. METHODS We detected the expression of AQP4 induced by Apelin-13 injection at 1, 3, and 7 days after middle cerebral artery occlusion. Meanwhile, we examined the effects of Apelin-13 on neurological function, infarct volume, and BBB disruption owing to cerebral ischemia in wild type mice, and tested whether such effects were AQP4 dependent by using AQP4 knock-out mice. Furthermore, we assessed the possible signal transduction pathways activated by Apelin-13 to regulate AQP4 expression via astrocyte cultures. RESULTS It was found that Apelin-13 highly increased AQP4 expression as well as reduced neurological scores and infarct volume. Importantly, Apelin-13 played a role of BBB protection in both types of mice by reducing BBB permeability, increased vascular endothelial growth factor, upregulated endothelial nitric oxide synthase, and downregulated inducible NOS. In morphology, we demonstrated Apelin-13 suppressed tight junction opening and endothelial cell swelling via electron microscopy detection. Meanwhile, Apelin-13 also alleviated apoptosis of astrocytes and promoted angiogenesis. Interestingly, effects of AQP4 on neurological function and infarct volume varied with time course, while AQP4 elicited protective effects on BBB at all time points. Statistical analysis of 2-way analysis of variance with replication indicated that AQP4 was required for these effects. In addition, Apelin-13 upregulated phosphorylation of extracellular signal-regulated kinase (ERK) and Akt as well as AQP4 protein in cultured astrocytes. The latter was inhibited by ERK and phosphatidylinositol 3'-kinase (PI3K) inhibitors. CONCLUSION Our data suggest that Apelin-13 protects BBB from disruption after cerebral ischemia both morphologically and functionally, which is highly associated with the increased levels of AQP4, possibly through the activation of ERK and PI3K/Akt pathways. This study provides double targets to protection of ischemic BBB damage, which can present new insights to drugs development.
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Affiliation(s)
- Heling Chu
- Department of Neurology, Huashan Hospital, State Key Laboratory of Medical Neurobiology, Shanghai, China
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Onoda A, Kawasaki T, Tsukiyama K, Takeda K, Umezawa M. Perivascular Accumulation of β-Sheet-Rich Proteins in Offspring Brain following Maternal Exposure to Carbon Black Nanoparticles. Front Cell Neurosci 2017; 11:92. [PMID: 28408868 PMCID: PMC5374146 DOI: 10.3389/fncel.2017.00092] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Accepted: 03/16/2017] [Indexed: 11/13/2022] Open
Abstract
Environmental stimulation during brain development is an important risk factor for the development of neurodegenerative disease. Clinical evidence indicates that prenatal exposure to particulate air pollutants leads to diffuse damage to the neurovascular unit in the developing brain and accelerates neurodegeneration. Maternal exposure to carbon black nanoparticles (CB-NPs), used as a model for particulate air pollution, induces long-lasting diffuse perivascular abnormalities. We aimed to comprehensively characterize the perivascular abnormalities related to maternal NPs exposure using Fourier transform infrared microspectroscopy (in situ FT-IR) and classical staining analysis. Pregnant ICR mice were intranasally treated with a CB-NPs suspension (95 μg/kg at a time) on gestational days 5 and 9. Brains were collected 6 weeks after birth and sliced to prepare 10-μm-thick serial sections. Reflective spectra of in situ FT-IR were acquired using lattice measurements (x-axis: 7, y-axis: 7, 30-μm apertures) around a centered blood vessel. We also performed mapping analysis of protein secondary structures. Serial sections were stained with using periodic acid-Schiff or immunofluorescence to examine the phenotypes of the perivascular areas. Peaks of amide I bands in spectra from perivascular areas were shifted by maternal NPs exposure. However, there were two types of peak-shift in one mouse in the exposure group. Some vessels had a large peak-shift and others had a small peak-shift. In situ FT-IR combined with traditional staining revealed that the large peak-shift was induced around blood vessel adjacent to astrocytes with glial fibrillary acidic protein and aquaporin-4 over-expression and perivascular macrophages (PVMs) with enlarged lysosome granules. Furthermore, protein secondary structural analysis indicated that maternal NPs exposure led to increases in β-sheet content and decreases in α-helix content in areas that are mostly close to the centered blood vessel displaying histopathological changes. These results suggest that β-sheet-rich waste proteins, which are denatured by maternal NPs exposure, likely accumulate in the perivascular space as they are processed by the clearance systems in the brain. This may in turn lead the denaturation of PVMs and astrocyte activation. The risk of neurodegeneration may be enhanced by exposure to particulate air pollutants during brain development following the perivascular accumulation of β-sheet-rich waste proteins.
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Affiliation(s)
- Atsuto Onoda
- Department of Hygienic Chemistry, Graduate School of Pharmaceutical Sciences, Tokyo University of ScienceNoda, Japan.,The Center for Environmental Health Science for the Next Generation, Research Institute for Science and Technology, Organization for Research Advancement, Tokyo University of ScienceNoda, Japan.,Research Fellow of Japan Society for the Promotion of ScienceTokyo, Japan
| | - Takayasu Kawasaki
- Infrared Free Electron Laser Research Center, Research Institute for Science and Technology, Organization for Research Advancement, Tokyo University of ScienceNoda, Japan
| | - Koichi Tsukiyama
- Infrared Free Electron Laser Research Center, Research Institute for Science and Technology, Organization for Research Advancement, Tokyo University of ScienceNoda, Japan.,Department of Chemistry, Faculty of Science, Tokyo University of ScienceTokyo, Japan
| | - Ken Takeda
- The Center for Environmental Health Science for the Next Generation, Research Institute for Science and Technology, Organization for Research Advancement, Tokyo University of ScienceNoda, Japan
| | - Masakazu Umezawa
- The Center for Environmental Health Science for the Next Generation, Research Institute for Science and Technology, Organization for Research Advancement, Tokyo University of ScienceNoda, Japan.,Department of Materials Science and Technology, Faculty of Industrial Science and Technology, Tokyo University of ScienceTokyo, Japan
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Kida T, Oku H, Horie T, Fukumoto M, Okuda Y, Morishita S, Ikeda T. Implication of VEGF and aquaporin 4 mediating Müller cell swelling to diabetic retinal edema. Graefes Arch Clin Exp Ophthalmol 2017; 255:1149-1157. [PMID: 28303331 DOI: 10.1007/s00417-017-3631-z] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Revised: 02/13/2017] [Accepted: 03/06/2017] [Indexed: 12/14/2022] Open
Abstract
PURPOSE Aquaporin 4 (AQP4), a water channel protein, is known to be expressed in retinal Müller cells. The purpose of this study was to determine the effects of VEGF and AQP4 channels on the volumetric changes in Müller cells. METHODS Retinas from diabetic rats and a cultured Müller cell line, TR-MUL5, were used in this study. Intravitreal injections of VEGF or PBS were performed on either streptozotocin (STZ)-induced diabetic or normoglycemic rats. Retinal sections were immunostained for anti-glial fibrillary acidic protein (GFAP), anti-AQP4, and anti-VEGF. VEGF protein levels from collected retinas were determined by western blot analysis. Volumetric changes and nitric oxide (NO) levels in cultured Müller cells were determined using flow cytometry (FACS), in the presence or absence of VEGF and TGN-020, a selective AQP4 inhibitor. RESULTS In the diabetic rat retina, VEGF immunoreactivity was concentrated in the internal retinal layers, and AQP4 immunoreactivity was higher than controls. The expressions of AQP4 were colocalized with GFAP. Protein levels of VEGF in the hyperglycemic rat retina were significantly higher than controls. FACS analyses showed that exposure to VEGF enlarged Müller cells, while exposure to TGN-020 suppressed the enlargement. Intracellular levels of NO were increased after exposure to VEGF, which was suppressed following the addition of TGN-020. CONCLUSION The observed Müller cell swelling is mediated by VEGF and AQP4.
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Affiliation(s)
- Teruyo Kida
- Department of Ophthalmology, Osaka Medical College, 2-7 Daigaku-machi, Takatsuki, Osaka, 569-8686, Japan.
| | - Hidehiro Oku
- Department of Ophthalmology, Osaka Medical College, 2-7 Daigaku-machi, Takatsuki, Osaka, 569-8686, Japan
| | - Taeko Horie
- Department of Ophthalmology, Osaka Medical College, 2-7 Daigaku-machi, Takatsuki, Osaka, 569-8686, Japan
| | - Masanori Fukumoto
- Department of Ophthalmology, Osaka Medical College, 2-7 Daigaku-machi, Takatsuki, Osaka, 569-8686, Japan
| | - Yoshitaka Okuda
- Department of Ophthalmology, Osaka Medical College, 2-7 Daigaku-machi, Takatsuki, Osaka, 569-8686, Japan
| | - Seita Morishita
- Department of Ophthalmology, Osaka Medical College, 2-7 Daigaku-machi, Takatsuki, Osaka, 569-8686, Japan
| | - Tsunehiko Ikeda
- Department of Ophthalmology, Osaka Medical College, 2-7 Daigaku-machi, Takatsuki, Osaka, 569-8686, Japan
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Desai B, Hsu Y, Schneller B, Hobbs JG, Mehta AI, Linninger A. Hydrocephalus: the role of cerebral aquaporin-4 channels and computational modeling considerations of cerebrospinal fluid. Neurosurg Focus 2016; 41:E8. [DOI: 10.3171/2016.7.focus16191] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Aquaporin-4 (AQP4) channels play an important role in brain water homeostasis. Water transport across plasma membranes has a critical role in brain water exchange of the normal and the diseased brain. AQP4 channels are implicated in the pathophysiology of hydrocephalus, a disease of water imbalance that leads to CSF accumulation in the ventricular system. Many molecular aspects of fluid exchange during hydrocephalus have yet to be firmly elucidated, but review of the literature suggests that modulation of AQP4 channel activity is a potentially attractive future pharmaceutical therapy. Drug therapy targeting AQP channels may enable control over water exchange to remove excess CSF through a molecular intervention instead of by mechanical shunting. This article is a review of a vast body of literature on the current understanding of AQP4 channels in relation to hydrocephalus, details regarding molecular aspects of AQP4 channels, possible drug development strategies, and limitations. Advances in medical imaging and computational modeling of CSF dynamics in the setting of hydrocephalus are summarized. Algorithmic developments in computational modeling continue to deepen the understanding of the hydrocephalus disease process and display promising potential benefit as a tool for physicians to evaluate patients with hydrocephalus.
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Affiliation(s)
| | - Ying Hsu
- 2Bioengineering, University of Illinois at Chicago; and
| | | | | | | | - Andreas Linninger
- Departments of 1Neurosurgery and
- 2Bioengineering, University of Illinois at Chicago; and
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Li J, Liu CN, Wei N, Li XD, Liu YY, Yang R, Jia YJ. Protective effects of BAY 73-6691, a selective inhibitor of phosphodiesterase 9, on amyloid-β peptides-induced oxidative stress in in-vivo and in-vitro models of Alzheimer's disease. Brain Res 2016; 1642:327-335. [DOI: 10.1016/j.brainres.2016.04.011] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2015] [Revised: 03/06/2016] [Accepted: 04/05/2016] [Indexed: 12/11/2022]
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