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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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Xu YW, Yang JS, Kang DZ, Yao PS. RETRACTED ARTICLE: Astrocytes Regulate Differentiation and Glutamate Uptake of Glioma Stem Cells via Formyl Peptide Receptor. Cell Mol Neurobiol 2021; 41:1389. [PMID: 32474726 DOI: 10.1007/s10571-020-00886-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Accepted: 05/25/2020] [Indexed: 11/30/2022]
Affiliation(s)
- Ya-Wen Xu
- Department of Neurosurgery, First Affiliated Hospital of Fujian Medical University, NO. 20 Chazhong Road, Taijiang District, Fuzhou, 350004, Fujian, China
| | - Jin-Shan Yang
- Department of Neurology, First Affiliated Hospital of Fujian Medical University, Fuzhou, China
| | - De-Zhi Kang
- Department of Neurosurgery, First Affiliated Hospital of Fujian Medical University, NO. 20 Chazhong Road, Taijiang District, Fuzhou, 350004, Fujian, China.
| | - Pei-Sen Yao
- Department of Neurosurgery, First Affiliated Hospital of Fujian Medical University, NO. 20 Chazhong Road, Taijiang District, Fuzhou, 350004, Fujian, China.
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Regan JT, Mirczuk SM, Scudder CJ, Stacey E, Khan S, Worwood M, Powles T, Dennis-Beron JS, Ginley-Hidinger M, McGonnell IM, Volk HA, Strickland R, Tivers MS, Lawson C, Lipscomb VJ, Fowkes RC. Sensitivity of the Natriuretic Peptide/cGMP System to Hyperammonaemia in Rat C6 Glioma Cells and GPNT Brain Endothelial Cells. Cells 2021; 10:cells10020398. [PMID: 33672024 PMCID: PMC7919485 DOI: 10.3390/cells10020398] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Revised: 02/05/2021] [Accepted: 02/11/2021] [Indexed: 12/16/2022] Open
Abstract
C-type natriuretic peptide (CNP) is the major natriuretic peptide of the central nervous system and acts via its selective guanylyl cyclase-B (GC-B) receptor to regulate cGMP production in neurons, astrocytes and endothelial cells. CNP is implicated in the regulation of neurogenesis, axonal bifurcation, as well as learning and memory. Several neurological disorders result in toxic concentrations of ammonia (hyperammonaemia), which can adversely affect astrocyte function. However, the relationship between CNP and hyperammonaemia is poorly understood. Here, we examine the molecular and pharmacological control of CNP in rat C6 glioma cells and rat GPNT brain endothelial cells, under conditions of hyperammonaemia. Concentration-dependent inhibition of C6 glioma cell proliferation by hyperammonaemia was unaffected by CNP co-treatment. Furthermore, hyperammonaemia pre-treatment (for 1 h and 24 h) caused a significant inhibition in subsequent CNP-stimulated cGMP accumulation in both C6 and GPNT cells, whereas nitric-oxide-dependent cGMP accumulation was not affected. CNP-stimulated cGMP efflux from C6 glioma cells was significantly reduced under conditions of hyperammonaemia, potentially via a mechanism involving changed in phosphodiesterase expression. Hyperammonaemia-stimulated ROS production was unaffected by CNP but enhanced by a nitric oxide donor in C6 cells. Extracellular vesicle production from C6 cells was enhanced by hyperammonaemia, and these vesicles caused impaired CNP-stimulated cGMP signalling in GPNT cells. Collectively, these data demonstrate functional interaction between CNP signalling and hyperammonaemia in C6 glioma and GPNT cells, but the exact mechanisms remain to be established.
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Affiliation(s)
- Jacob T. Regan
- Endocrine Signalling Group, Department of Comparative Biomedical Sciences, The Royal Veterinary College, University of London, Royal College Street, London NW1 0TU, UK; (J.T.R.); (S.M.M.); (C.J.S.); (E.S.); (S.K.); (M.W.); (T.P.); (J.S.D.-B.); (M.G.-H.)
| | - Samantha M. Mirczuk
- Endocrine Signalling Group, Department of Comparative Biomedical Sciences, The Royal Veterinary College, University of London, Royal College Street, London NW1 0TU, UK; (J.T.R.); (S.M.M.); (C.J.S.); (E.S.); (S.K.); (M.W.); (T.P.); (J.S.D.-B.); (M.G.-H.)
- Department of Comparative Biomedical Sciences, The Royal Veterinary College, University of London, Royal College Street, London NW1 0TU, UK; (I.M.M.); (C.L.)
| | - Christopher J. Scudder
- Endocrine Signalling Group, Department of Comparative Biomedical Sciences, The Royal Veterinary College, University of London, Royal College Street, London NW1 0TU, UK; (J.T.R.); (S.M.M.); (C.J.S.); (E.S.); (S.K.); (M.W.); (T.P.); (J.S.D.-B.); (M.G.-H.)
- Department of Comparative Biomedical Sciences, The Royal Veterinary College, University of London, Royal College Street, London NW1 0TU, UK; (I.M.M.); (C.L.)
| | - Emily Stacey
- Endocrine Signalling Group, Department of Comparative Biomedical Sciences, The Royal Veterinary College, University of London, Royal College Street, London NW1 0TU, UK; (J.T.R.); (S.M.M.); (C.J.S.); (E.S.); (S.K.); (M.W.); (T.P.); (J.S.D.-B.); (M.G.-H.)
| | - Sabah Khan
- Endocrine Signalling Group, Department of Comparative Biomedical Sciences, The Royal Veterinary College, University of London, Royal College Street, London NW1 0TU, UK; (J.T.R.); (S.M.M.); (C.J.S.); (E.S.); (S.K.); (M.W.); (T.P.); (J.S.D.-B.); (M.G.-H.)
| | - Michael Worwood
- Endocrine Signalling Group, Department of Comparative Biomedical Sciences, The Royal Veterinary College, University of London, Royal College Street, London NW1 0TU, UK; (J.T.R.); (S.M.M.); (C.J.S.); (E.S.); (S.K.); (M.W.); (T.P.); (J.S.D.-B.); (M.G.-H.)
| | - Torinn Powles
- Endocrine Signalling Group, Department of Comparative Biomedical Sciences, The Royal Veterinary College, University of London, Royal College Street, London NW1 0TU, UK; (J.T.R.); (S.M.M.); (C.J.S.); (E.S.); (S.K.); (M.W.); (T.P.); (J.S.D.-B.); (M.G.-H.)
| | - J. Sebastian Dennis-Beron
- Endocrine Signalling Group, Department of Comparative Biomedical Sciences, The Royal Veterinary College, University of London, Royal College Street, London NW1 0TU, UK; (J.T.R.); (S.M.M.); (C.J.S.); (E.S.); (S.K.); (M.W.); (T.P.); (J.S.D.-B.); (M.G.-H.)
| | - Matthew Ginley-Hidinger
- Endocrine Signalling Group, Department of Comparative Biomedical Sciences, The Royal Veterinary College, University of London, Royal College Street, London NW1 0TU, UK; (J.T.R.); (S.M.M.); (C.J.S.); (E.S.); (S.K.); (M.W.); (T.P.); (J.S.D.-B.); (M.G.-H.)
| | - Imelda M. McGonnell
- Department of Comparative Biomedical Sciences, The Royal Veterinary College, University of London, Royal College Street, London NW1 0TU, UK; (I.M.M.); (C.L.)
| | - Holger A. Volk
- Stiftung Tierärztliche Hochschule Hannover, Klinik für Kleintiere, Bünteweg, 930559 Hannover, Germany;
| | - Rhiannon Strickland
- Clinical Sciences & Services, Hawkshead Lane, North Mymms, Hatfield, Hertfordshire AL9 7TA, UK; (R.S.); (V.J.L.)
| | - Michael S. Tivers
- Paragon Veterinary Referrals, Paragon Business Village Paragon Way, Red Hall Cres, Wakefield WF1 2DF, UK;
| | - Charlotte Lawson
- Department of Comparative Biomedical Sciences, The Royal Veterinary College, University of London, Royal College Street, London NW1 0TU, UK; (I.M.M.); (C.L.)
| | - Victoria J. Lipscomb
- Clinical Sciences & Services, Hawkshead Lane, North Mymms, Hatfield, Hertfordshire AL9 7TA, UK; (R.S.); (V.J.L.)
| | - Robert C. Fowkes
- Endocrine Signalling Group, Department of Comparative Biomedical Sciences, The Royal Veterinary College, University of London, Royal College Street, London NW1 0TU, UK; (J.T.R.); (S.M.M.); (C.J.S.); (E.S.); (S.K.); (M.W.); (T.P.); (J.S.D.-B.); (M.G.-H.)
- Department of Comparative Biomedical Sciences, The Royal Veterinary College, University of London, Royal College Street, London NW1 0TU, UK; (I.M.M.); (C.L.)
- Correspondence: ; Tel.: +44-207-468-1215
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Coutinho LG, de Oliveira AHS, Witwer M, Leib SL, Agnez-Lima LF. DNA repair protein APE1 is involved in host response during pneumococcal meningitis and its expression can be modulated by vitamin B6. J Neuroinflammation 2017; 14:243. [PMID: 29233148 PMCID: PMC5727666 DOI: 10.1186/s12974-017-1020-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Accepted: 12/04/2017] [Indexed: 01/01/2023] Open
Abstract
Background The production of reactive oxygen species (ROS) during pneumococcal meningitis (PM) leads to severe DNA damage in the neurons and is the major cause of cell death during infection. Hence, the use of antioxidants as adjuvant therapy has been investigated. Previous studies have demonstrated the possible participation of apurinic/apyrimidinic endonuclease (APE1) during PM. The aims of this study were to investigate the APE1 expression in the cortical and hippocampal tissues of infant Wistar rats infected with Streptococcus pneumoniae and its association with cell death and understand the role of vitamin B6 (vitB6) as a protective factor against cell death. Methods APE1 expression and oxidative stress markers were analyzed at two-time points, 20 and 24 h post infection (p.i.), in the cortex (CX) and hippocampus (HC) of rats supplemented with vitB6. Statistical analyses were performed by the nonparametric Kruskal–Wallis test using Dunn’s post test. Results Our results showed high protein levels of APE1 in CX and HC of infected rats. In the CX, at 20 h p.i., vitB6 supplementation led to the reduction of expression of APE1 and apoptosis-inducing factor, while no significant changes in the transcript levels of caspase-3 were observed. Furthermore, levels of carbonyl content and glutamate in the CX were reduced by vitB6 supplementation at the same time point of 20 h p.i.. Since our data showed a significant effect of vitB6 on the CX at 20 h p.i. rather than that at 24 h p.i., we evaluated the effect of administering a second dose of vitB6 at 18 h p.i. and sacrifice at 24 h p.i.. Reduction in the oxidative stress and APE1 levels were observed, although the latter was not significant. Although the levels of APE1 was not significantly changed in the HC with vitB6 adjuvant therapy, vitB6 supplementation prevented the formation of the truncated form of APE1 (34 kDa) that is associated with apoptosis. Conclusions Our data suggest that PM affects APE1 expression, which can be modulated by vitB6. Additionally, vitB6 contributes to the reduction of glutamate and ROS levels. Besides the potential to reduce cell death and oxidative stress during neuroinflammation, vitB6 showed enhanced effect on the CX than on the HC during PM.
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Affiliation(s)
- Leonam G Coutinho
- Departamento de Biologia Celular e Genética, Centro de Biociências, Universidade Federal do Rio Grande do Norte, UFRN, Campus Universitário, Lagoa Nova, Natal, RN, 59078-900, Brazil.,Instituto Federal de Educação Tecnológica do Rio Grande do Norte, IFRN, Natal, Brazil
| | | | - Matthias Witwer
- Institute for Infectious Diseases, University of Bern, Friedbuehlstrasse 51, CH-3010, Bern, Switzerland
| | - Stephen L Leib
- Institute for Infectious Diseases, University of Bern, Friedbuehlstrasse 51, CH-3010, Bern, Switzerland
| | - Lucymara F Agnez-Lima
- Departamento de Biologia Celular e Genética, Centro de Biociências, Universidade Federal do Rio Grande do Norte, UFRN, Campus Universitário, Lagoa Nova, Natal, RN, 59078-900, Brazil.
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Abusneina A, Gauthier ER. Ammonium ions improve the survival of glutamine-starved hybridoma cells. Cell Biosci 2016; 6:23. [PMID: 27087916 PMCID: PMC4832542 DOI: 10.1186/s13578-016-0092-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Accepted: 04/04/2016] [Indexed: 12/17/2022] Open
Abstract
Background As a consequence of a reprogrammed metabolism, cancer cells are dependent on the amino acid l-glutamine for their survival, a phenomenon that currently forms the basis for the generation of new, cancer-specific therapies. In this paper, we report on the role which ammonium ions, a product of glutaminolysis, play on the survival of l-glutamine-deprived Sp2/0-Ag14 mouse hybridoma cells. Results The supplementation of l-glutamine-starved Sp2/0-Ag14 cell cultures with either ammonium acetate or ammonium chloride resulted in a significant increase in viability. This effect did not depend on the ability of cells to synthesize l-glutamine, and was not affected by the co-supplementation with α-ketoglutarate. When we examined the effect of ammonium acetate and ammonium chloride on the induction of apoptosis by glutamine deprivation, we found that ammonium salts did not prevent caspase-3 activation or cytochrome c leakage, indicating that they did not act by modulating core apoptotic processes. However, both ammonium acetate and ammonium chloride caused a significant reduction in the number of l-glutamine-starved cells exhibiting apoptotic nuclear fragmentation and/or condensation. Conclusion All together, our results show that ammonium ions promote the survival of l-glutamine-deprived Sp2/0-Ag14 cells and modulate late-apoptotic events. These findings highlight the complexity of the modulation of cell survival by l-glutamine, and suggest that targeting survival-signaling pathways modulated by ammonium ions should be examined as a potential anti-cancer strategy.
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Affiliation(s)
| | - Eric R Gauthier
- Biomolecular Sciences, Laurentian University, Sudbury, ON P3E 2C6 Canada ; Department of Chemistry and Biochemistry, Laurentian University, Sudbury, ON P3E 2C6 Canada ; Department of Biology, Laurentian University, Sudbury, ON P3E 2C6 Canada
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Liang HJ, Chai RC, Li X, Kong JG, Jiang JH, Ma J, Vatcher G, Yu ACH. Astrocytic exportin-7 responds to ischemia through mediating LKB1 translocation from the nucleus to the cytoplasm. J Neurosci Res 2014; 93:253-67. [PMID: 25250856 DOI: 10.1002/jnr.23486] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2014] [Revised: 07/16/2014] [Accepted: 08/18/2014] [Indexed: 11/06/2022]
Abstract
The superfamily of importin-β-related proteins is the largest class of nuclear transport receptors and can be generally divided into importins and exportins according to their transport directions. Eleven importins and seven exportins have been identified, and the expression patterns of both classes are important for their functions in nucleocytoplasmic transport activities. This study demonstrates that all of the importins (importin-β; transportin-1, -2, and -3; and importin-4, -5, -7, -8, -9, -11, and -13) and all the exportins (exportin-1, -2, -4, -5, -6, -7, and -t) are differentially expressed in the cerebral cortex, cerebellum, hippocampus, and brainstem and in primary cultures of cerebral cortical astrocytes and neurons. For astrocytes, we observed that different importins and exportins displayed different expression changes during 0-6 hr of ischemia treatment, especially an increase of both the mRNA and the protein of exportin-7. Immunostaining showed that exportin-7 accumulated inside the nucleus and around the nuclear envelope. In addition, we noticed an increased cytoplasmic distribution of one of the cargo proteins of exportin-7, LKB1, an important element in maintaining energy homeostasis. This increased cytoplasmic distribution was accompanied by an increased expression of exportin-7 under ischemia in astrocytes. We demonstrate that exportin-7 responds to ischemia in astrocytes and that this response involves translocation of LKB1, a protein that plays important roles during metabolic stress, from the nucleus to the cytoplasm.
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Affiliation(s)
- Hai Jie Liang
- Neuroscience Research Institute and Department of Neurobiology, School of Basic Medical Sciences, Peking University, Beijing, China; Key Laboratory for Neuroscience of the Ministry of Education and Key Laboratory for Neuroscience of the National Health and Family Planning Commission, Peking University, Beijing, China
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Chai RC, Jiang JH, Wong AYK, Jiang F, Gao K, Vatcher G, Hoi Yu AC. AQP5 is differentially regulated in astrocytes during metabolic and traumatic injuries. Glia 2013; 61:1748-65. [PMID: 23922257 DOI: 10.1002/glia.22555] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2013] [Revised: 05/30/2013] [Accepted: 06/17/2013] [Indexed: 01/14/2023]
Abstract
Water movement plays vital roles in both physiological and pathological conditions in the brain. Astrocytes are responsible for regulating this water movement and are the major contributors to brain edema in pathological conditions. Aquaporins (AQPs) in astrocytes play critical roles in the regulation of water movement in the brain. AQP1, 3, 4, 5, 8, and 9 have been reported in the brain. Compared with AQP1, 4, and 9, AQP3, 5, and 8 are less studied. Among the lesser known AQPs, AQP5, which has multiple functions identified outside the central nervous system, is also indicated to be involved in hypoxia injury in astrocytes. In our study, AQP5 expression could be detected both in primary cultures of astrocytes and neurons, and AQP5 expression in astrocytes was confirmed in 1- to 4-week old primary cultures of astrocytes. AQP5 was localized on the cytoplasmic membrane and in the cytoplasm of astrocytes. AQP5 expression was downregulated during ischemia treatment and upregulated after scratch-wound injury, which was also confirmed in a middle cerebral artery occlusion model and a stab-wound injury model in vivo. The AQP5 increased after scratch injury was polarized to the migrating processes and cytoplasmic membrane of astrocytes in the leading edge of the scratch-wound, and AQP5 over-expression facilitated astrocyte process elongation after scratch injury. Taken together, these results indicate that AQP5 might be an important water channel in astrocytes that is differentially expressed during various brain injuries.
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Affiliation(s)
- Rui Chao Chai
- Neuroscience Research Institute & Department of Neurobiology, School of Basic Medical Sciences, Peking University, Beijing 100191, China
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