201
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Hasan-Olive MM, Hansson HA, Enger R, Nagelhus EA, Eide PK. Blood-Brain Barrier Dysfunction in Idiopathic Intracranial Hypertension. J Neuropathol Exp Neurol 2020; 78:808-818. [PMID: 31393574 DOI: 10.1093/jnen/nlz063] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2019] [Revised: 06/01/2019] [Accepted: 06/27/2019] [Indexed: 12/18/2022] Open
Abstract
Idiopathic intracranial hypertension (IIH) is traditionally considered benign and characterized by symptoms related to increased intracranial pressure, including headache and impaired vision. We have previously demonstrated that brains of IIH patients exhibit patchy astrogliosis, increased perivascular expression of the water channel aquaporin-4 (AQP4) as well as degenerating pericyte processes and capillary basement membranes. Given the established association between pericyte degeneration and blood-brain barrier (BBB) dysfunction, we investigated blood protein leakage by light microscopic immunohistochemistry. We also assessed perivascular AQP4 expression by immunogold transmission electron microscopy. The study included 14 IIH patients and 14 reference (REF) subjects undergoing neurosurgery for epilepsy, aneurysm, or tumor. Evidence of BBB dysfunction, measured as area extravasated fibrinogen/fibrin, was significantly more pronounced in IIH than REF individuals. The extent of extravasated fibrinogen was positively correlated with increasing degree of astrogliosis and vascular AQP4 immunoreactivity, determined by light microscopy. Immunogold transmission electron microscopy revealed no overall changes in AQP4 expression at astrocytic vascular endfeet in IIH (n = 8) compared to REF (n = 11) individuals. Our results provide evidence of BBB leakage in IIH, signifying that IIH is a more serious neurodegenerative disease than previously considered.
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Affiliation(s)
- Md Mahdi Hasan-Olive
- Department of Neurosurgery, Oslo University Hospital - Rikshospitalet.,Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Hans-Arne Hansson
- Institute of Biomedicine, University of Gothenburg, Göteborg, Sweden
| | - Rune Enger
- GliaLab and Letten Centre, Division of Physiology, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo.,Department of Neurology, Oslo University Hospital - Rikshospitalet, Oslo, Norway
| | - Erlend A Nagelhus
- GliaLab and Letten Centre, Division of Physiology, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo.,Department of Neurology, Oslo University Hospital - Rikshospitalet, Oslo, Norway
| | - Per Kristian Eide
- Department of Neurosurgery, Oslo University Hospital - Rikshospitalet.,Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway
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202
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Wander CM, Tseng JH, Song S, Al Housseiny HA, Tart DS, Ajit A, Ian Shih YY, Lobrovich R, Song J, Meeker RB, Irwin DJ, Cohen TJ. The Accumulation of Tau-Immunoreactive Hippocampal Granules and Corpora Amylacea Implicates Reactive Glia in Tau Pathogenesis during Aging. iScience 2020; 23:101255. [PMID: 32585593 PMCID: PMC7322077 DOI: 10.1016/j.isci.2020.101255] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Revised: 05/19/2020] [Accepted: 06/05/2020] [Indexed: 01/26/2023] Open
Abstract
The microtubule-associated tau protein forms pathological inclusions that accumulate in an age-dependent manner in tauopathies including Alzheimer's disease (AD). Since age is the major risk factor for AD, we examined endogenous tau species that evolve during aging in physiological and diseased conditions. In aged mouse brain, we found tau-immunoreactive clusters embedded within structures that are reminiscent of periodic acid-Schiff (PAS) granules. We showed that PAS granules harbor distinct tau species that are more prominent in 3xTg-AD mice. Epitope profiling revealed hypo-phosphorylated rather than hyper-phosphorylated tau commonly observed in tauopathies. High-resolution imaging and 3D reconstruction suggest a link between tau clusters, reactive astrocytes, and microglia, indicating that early tau accumulation may promote neuroinflammation during aging. Using postmortem human brain, we identified tau as a component of corpora amylacea (CA), age-related structures that are functionally analogous to PAS granules. Overall, our study supports neuroimmune dysfunction as a precipitating event in tau pathogenesis. Tau is present in mouse hippocampal granules and human corpora amylacea Tau accumulates with age in hippocampal granules and is accelerated in 3xTg-AD mice Tau immunoreactive corpora amylacea are present in Alzheimer's disease brain Age-related tau deposits are associated with reactive astrocytes
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Affiliation(s)
- Connor M Wander
- Department of Pharmacology, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Jui-Heng Tseng
- Department of Neurology, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Sheng Song
- Department of Neurology, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Heba A Al Housseiny
- Department of Pharmacology, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Dalton S Tart
- Department of Pharmacology, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Aditi Ajit
- Department of Neurology, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Yen-Yu Ian Shih
- Department of Neurology, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Rebecca Lobrovich
- Penn Digital Neuropathology Laboratory, Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-4283, USA
| | - Juan Song
- Department of Pharmacology, University of North Carolina, Chapel Hill, NC 27599, USA; UNC Neuroscience Center, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Rick B Meeker
- Department of Neurology, University of North Carolina, Chapel Hill, NC 27599, USA
| | - David J Irwin
- Penn Digital Neuropathology Laboratory, Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-4283, USA
| | - Todd J Cohen
- Department of Neurology, University of North Carolina, Chapel Hill, NC 27599, USA; UNC Neuroscience Center, University of North Carolina, Chapel Hill, NC 27599, USA; Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, NC 27599, USA.
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203
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Channels that Cooperate with TRPV4 in the Brain. J Mol Neurosci 2020; 70:1812-1820. [PMID: 32524421 DOI: 10.1007/s12031-020-01574-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2020] [Accepted: 04/27/2020] [Indexed: 12/26/2022]
Abstract
Transient receptor potential vanilloid 4 (TRPV4) is a nonselective Ca2+-permeable cation channel that is a member of the TRP channel family. It is clear that TRPV4 channels are broadly expressed in the brain. As they are expressed on the plasma membrane, they interact with other channels and play a crucial role in nervous system activity. Under some pathological conditions, TRPV4 channels are upregulated and sensitized via cellular signaling pathways, and this can cause nervous system diseases. In this review, we focus on receptors that cooperate with TRPV4, including large-conductance Ca2+-activated K+(BKca) channels, N-methyl-D-aspartate receptors (NMDARs), α-amino-3-hydroxy-5-methyl-4-isoxazole-propionate receptors (AMPARs), inositol 1,4,5-trisphosphate receptors (IP3Rs), ryanodine receptors (RyRs), aquaporin 4 (AQP4), and other potential cooperative receptors in the brain. The data demonstrate how these channels work together to cause nervous system diseases under pathological conditions. The aim of this review was to discuss the receptors and signaling pathways related to TRPV4 based on recent data on the important physiological functions of TRPV4 channels to provide new clues for future studies and prospective therapeutic targets for related brain diseases.
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204
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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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205
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Jurisch-Yaksi N, Yaksi E, Kizil C. Radial glia in the zebrafish brain: Functional, structural, and physiological comparison with the mammalian glia. Glia 2020; 68:2451-2470. [PMID: 32476207 DOI: 10.1002/glia.23849] [Citation(s) in RCA: 80] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Revised: 05/07/2020] [Accepted: 05/13/2020] [Indexed: 02/01/2023]
Abstract
The neuroscience community has witnessed a tremendous expansion of glia research. Glial cells are now on center stage with leading roles in the development, maturation, and physiology of brain circuits. Over the course of evolution, glia have highly diversified and include the radial glia, astroglia or astrocytes, microglia, oligodendrocytes, and ependymal cells, each having dedicated functions in the brain. The zebrafish, a small teleost fish, is no exception to this and recent evidences point to evolutionarily conserved roles for glia in the development and physiology of its nervous system. Due to its small size, transparency, and genetic amenability, the zebrafish has become an increasingly prominent animal model for brain research. It has enabled the study of neural circuits from individual cells to entire brains, with a precision unmatched in other vertebrate models. Moreover, its high neurogenic and regenerative potential has attracted a lot of attention from the research community focusing on neural stem cells and neurodegenerative diseases. Hence, studies using zebrafish have the potential to provide fundamental insights about brain development and function, and also elucidate neural and molecular mechanisms of neurological diseases. We will discuss here recent discoveries on the diverse roles of radial glia and astroglia in neurogenesis, in modulating neuronal activity and in regulating brain homeostasis at the brain barriers. By comparing insights made in various animal models, particularly mammals and zebrafish, our goal is to highlight the similarities and differences in glia biology among species, which could set new paradigms relevant to humans.
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Affiliation(s)
- Nathalie Jurisch-Yaksi
- Kavli Institute for Systems Neuroscience and Centre for Neural Computation, Norwegian University of Science and Technology, Trondheim, Norway.,Department of Clinical and Molecular Medicine, Norwegian University of Science and Technology, Trondheim, Norway.,Department of Neurology and Clinical Neurophysiology, St Olav University Hospital, Trondheim, Norway
| | - Emre Yaksi
- Kavli Institute for Systems Neuroscience and Centre for Neural Computation, Norwegian University of Science and Technology, Trondheim, Norway
| | - Caghan Kizil
- German Center for Neurodegenerative Diseases (DZNE), Helmholtz Association, Dresden, Germany.,Center for Molecular and Cellular Bioengineering (CMCB), TU Dresden, Dresden, Germany
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206
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Dasdelen D, Mogulkoc R, Baltaci AK. Aquaporins and Roles in Brain Health and Brain Injury. Mini Rev Med Chem 2020; 20:498-512. [DOI: 10.2174/1389557519666191018142007] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Revised: 05/07/2019] [Accepted: 10/03/2019] [Indexed: 02/08/2023]
Abstract
In the literature screening, aquaporins were found in the cerebral structures including the pia mater, choroid plexus, ependyma, piriform cortex, hippocampus, dorsal thalamus, supraoptic and suprachiasmatic nuclei, white matter and subcortical organ. Among these, the most common are AQP1, AQP4, and AQP9. The roles of aquaporins have been demonstrated in several diseases such as cerebral edema, various central nervous system tumors, Alzheimer’s Disease and epilepsy. In this review, the relationship between brain/brain-injury and aquaporin, has been reviewed.
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Affiliation(s)
- Dervis Dasdelen
- Department of Physiology, Medical Faculty, Selcuk University, Konya, Turkey
| | - Rasim Mogulkoc
- Department of Physiology, Medical Faculty, Selcuk University, Konya, Turkey
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207
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Cash A, Theus MH. Mechanisms of Blood-Brain Barrier Dysfunction in Traumatic Brain Injury. Int J Mol Sci 2020; 21:ijms21093344. [PMID: 32397302 PMCID: PMC7246537 DOI: 10.3390/ijms21093344] [Citation(s) in RCA: 121] [Impact Index Per Article: 30.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 05/02/2020] [Accepted: 05/04/2020] [Indexed: 12/16/2022] Open
Abstract
Traumatic brain injuries (TBIs) account for the majority of injury-related deaths in the United States with roughly two million TBIs occurring annually. Due to the spectrum of severity and heterogeneity in TBIs, investigation into the secondary injury is necessary in order to formulate an effective treatment. A mechanical consequence of trauma involves dysregulation of the blood–brain barrier (BBB) which contributes to secondary injury and exposure of peripheral components to the brain parenchyma. Recent studies have shed light on the mechanisms of BBB breakdown in TBI including novel intracellular signaling and cell–cell interactions within the BBB niche. The current review provides an overview of the BBB, novel detection methods for disruption, and the cellular and molecular mechanisms implicated in regulating its stability following TBI.
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Affiliation(s)
- Alison Cash
- The Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Blacksburg, VA 24061, USA;
| | - Michelle H. Theus
- The Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Blacksburg, VA 24061, USA;
- The Center for Regenerative Medicine, Virginia-Maryland College of Veterinary Medicine, Blacksburg, VA 24061, USA
- Correspondence: ; Tel.: 1-540-231-0909; Fax: 1-540-231-7425
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208
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Alquisiras-Burgos I, Ortiz-Plata A, Franco-Pérez J, Millán A, Aguilera P. Resveratrol reduces cerebral edema through inhibition of de novo SUR1 expression induced after focal ischemia. Exp Neurol 2020; 330:113353. [PMID: 32380020 DOI: 10.1016/j.expneurol.2020.113353] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Revised: 04/26/2020] [Accepted: 05/01/2020] [Indexed: 12/21/2022]
Abstract
Cerebral edema is a clinical problem that frequently follows ischemic infarcts. Sulfonylurea receptor 1 (SUR1) is an inducible protein that can form a heteromultimeric complex with aquaporin 4 (AQP4) that mediate the ion/water transport involved in brain tissue swelling. Transcription of the Abcc8 gene coding for SUR1 depends on the activity of transcriptional factor SP1, which is modulated by the cellular redox environment. Since oxidative stress is implicated in the induced neuronal damage in ischemia and edema formation, the present study aimed to evaluate if the antioxidant resveratrol (RSV) prevents the damage by reducing the de novo expression of SUR1 in the ischemic brain. Male Wistar rats were subjected to 2 h of middle cerebral artery occlusion followed by different times of reperfusion. RSV (1.9 mg/kg; i.v.) was administered at the onset of reperfusion. Brain damage and edema formation were recognized by neurological evaluation, time of survival, TTC (2,3,5-Triphenyltetrazolium chloride) staining, Evans blue extravasation, and water content. RSV mechanism of action was studied by SP1 binding activity measured through the Electrophoretic Mobility Shift Assay, and Abcc8 and Aqp4 gene expression evaluated by qPCR, immunofluorescence, and Western blot. We found that RSV reduced the infarct area and cerebral edema, prevented blood-brain barrier damage, improved neurological performance, and increased survival. Additionally, our findings suggest that the antioxidant activity of RSV targeted SP transcription factors and inhibited SUR1 and AQP4 expression. Thus, RSV by decreasing SUR1 expression could contribute to reducing edema formation, constituting a therapeutic alternative for edema reduction in stroke.
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Affiliation(s)
- Iván Alquisiras-Burgos
- Laboratorio de Patología Vascular Cerebral, Instituto Nacional de Neurología y Neurocirugía "Manuel Velasco Suárez", Insurgentes Sur #3877, CDMX 14269, México
| | - Alma Ortiz-Plata
- Laboratorio de Neuropatología Experimental, Instituto Nacional de Neurología y Neurocirugía "Manuel Velasco Suárez", Insurgentes Sur #3877, CDMX 14269, México.
| | - Javier Franco-Pérez
- Laboratorio de Formación Reticular, Instituto Nacional de Neurología y Neurocirugía "Manuel Velasco Suárez", Insurgentes Sur #3877, CDMX 14269, México.
| | - Alejandro Millán
- Posgrado en Ciencias Biomédicas, Facultad de Ciencias Químico-Biológicas, Universidad Autónoma de Guerrero, Lázaro Cárdenas s/n Ciudad Universitaria, Chilpancingo, Guerrero, 39070, México
| | - Penélope Aguilera
- Laboratorio de Patología Vascular Cerebral, Instituto Nacional de Neurología y Neurocirugía "Manuel Velasco Suárez", Insurgentes Sur #3877, CDMX 14269, México.
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209
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Gollihue J, Norris C. Astrocyte mitochondria: Central players and potential therapeutic targets for neurodegenerative diseases and injury. Ageing Res Rev 2020; 59:101039. [PMID: 32105849 DOI: 10.1016/j.arr.2020.101039] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Revised: 01/23/2020] [Accepted: 02/23/2020] [Indexed: 01/16/2023]
Abstract
Mitochondrial function has long been the focus of many therapeutic strategies for ameliorating age-related neurodegeneration and cognitive decline. Historically, the role of mitochondria in non-neuronal cell types has been overshadowed by neuronal mitochondria, which are responsible for the bulk of oxidative metabolism in the brain. Despite this neuronal bias, mitochondrial function in glial cells, particularly astrocytes, is increasingly recognized to play crucial roles in overall brain metabolism, synaptic transmission, and neuronal protection. Changes in astrocytic mitochondrial function appear to be intimately linked to astrocyte activation/reactivity found in most all age-related neurodegenerative diseases. Here, we address the importance of mitochondrial function to astrocyte signaling and consider how mitochondria could contribute to both the detrimental and protective properties of activated astrocytes. Strategies for protecting astrocytic mitochondrial function, promoting bidirectional transfer of mitochondria between astrocytes and neurons, and transplanting healthy mitochondria to diseased nervous tissue are also discussed.
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210
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Troili F, Cipollini V, Moci M, Morena E, Palotai M, Rinaldi V, Romano C, Ristori G, Giubilei F, Salvetti M, Orzi F, Guttmann CRG, Cavallari M. Perivascular Unit: This Must Be the Place. The Anatomical Crossroad Between the Immune, Vascular and Nervous System. Front Neuroanat 2020; 14:17. [PMID: 32372921 PMCID: PMC7177187 DOI: 10.3389/fnana.2020.00017] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Accepted: 03/23/2020] [Indexed: 12/25/2022] Open
Abstract
Most neurological disorders seemingly have heterogenous pathogenesis, with overlapping contribution of neuronal, immune and vascular mechanisms of brain injury. The perivascular space in the brain represents a crossroad where those mechanisms interact, as well as a key anatomical component of the recently discovered glymphatic pathway, which is considered to play a crucial role in the clearance of brain waste linked to neurodegenerative diseases. The pathological interplay between neuronal, immune and vascular factors can create an environment that promotes self-perpetration of mechanisms of brain injury across different neurological diseases, including those that are primarily thought of as neurodegenerative, neuroinflammatory or cerebrovascular. Changes of the perivascular space can be monitored in humans in vivo using magnetic resonance imaging (MRI). In the context of glymphatic clearance, MRI-visible enlarged perivascular spaces (EPVS) are considered to reflect glymphatic stasis secondary to the perivascular accumulation of brain debris, although they may also represent an adaptive mechanism of the glymphatic system to clear them. EPVS are also established correlates of dementia and cerebral small vessel disease (SVD) and are considered to reflect brain inflammatory activity. In this review, we describe the “perivascular unit” as a key anatomical and functional substrate for the interaction between neuronal, immune and vascular mechanisms of brain injury, which are shared across different neurological diseases. We will describe the main anatomical, physiological and pathological features of the perivascular unit, highlight potential substrates for the interplay between different noxae and summarize MRI studies of EPVS in cerebrovascular, neuroinflammatory and neurodegenerative disorders.
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Affiliation(s)
- Fernanda Troili
- Department of Neurosciences Mental Health and Sensory Organs, Faculty of Medicine and Psychology, Sapienza University of Rome, Rome, Italy
| | - Virginia Cipollini
- Department of Neurosciences Mental Health and Sensory Organs, Faculty of Medicine and Psychology, Sapienza University of Rome, Rome, Italy
| | - Marco Moci
- Department of Medicine, Surgery and Dentistry, "Scuola Medica Salernitana", Neuroscience Section, University of Salerno, Baronissi, Italy
| | - Emanuele Morena
- Department of Neurosciences Mental Health and Sensory Organs, Faculty of Medicine and Psychology, Sapienza University of Rome, Rome, Italy
| | - Miklos Palotai
- Harvard Medical School, Center for Neurological Imaging, Brigham and Women's Hospital, Boston, MA, United States
| | - Virginia Rinaldi
- Department of Neurosciences Mental Health and Sensory Organs, Faculty of Medicine and Psychology, Sapienza University of Rome, Rome, Italy
| | - Carmela Romano
- Department of Neurosciences Mental Health and Sensory Organs, Faculty of Medicine and Psychology, Sapienza University of Rome, Rome, Italy
| | - Giovanni Ristori
- Department of Neurosciences Mental Health and Sensory Organs, Faculty of Medicine and Psychology, Sapienza University of Rome, Rome, Italy
| | - Franco Giubilei
- Department of Neurosciences Mental Health and Sensory Organs, Faculty of Medicine and Psychology, Sapienza University of Rome, Rome, Italy
| | - Marco Salvetti
- Department of Neurosciences Mental Health and Sensory Organs, Faculty of Medicine and Psychology, Sapienza University of Rome, Rome, Italy
| | - Francesco Orzi
- Department of Neurosciences Mental Health and Sensory Organs, Faculty of Medicine and Psychology, Sapienza University of Rome, Rome, Italy
| | - Charles R G Guttmann
- Harvard Medical School, Center for Neurological Imaging, Brigham and Women's Hospital, Boston, MA, United States
| | - Michele Cavallari
- Harvard Medical School, Center for Neurological Imaging, Brigham and Women's Hospital, Boston, MA, United States
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211
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Montgomery MK, Kim SH, Dovas A, Zhao HT, Goldberg AR, Xu W, Yagielski AJ, Cambareri MK, Patel KB, Mela A, Humala N, Thibodeaux DN, Shaik MA, Ma Y, Grinband J, Chow DS, Schevon C, Canoll P, Hillman EMC. Glioma-Induced Alterations in Neuronal Activity and Neurovascular Coupling during Disease Progression. Cell Rep 2020; 31:107500. [PMID: 32294436 PMCID: PMC7443283 DOI: 10.1016/j.celrep.2020.03.064] [Citation(s) in RCA: 55] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Revised: 02/10/2020] [Accepted: 03/18/2020] [Indexed: 12/14/2022] Open
Abstract
Diffusely infiltrating gliomas are known to cause alterations in cortical function, vascular disruption, and seizures. These neurological complications present major clinical challenges, yet their underlying mechanisms and causal relationships to disease progression are poorly characterized. Here, we follow glioma progression in awake Thy1-GCaMP6f mice using in vivo wide-field optical mapping to monitor alterations in both neuronal activity and functional hemodynamics. The bilateral synchrony of spontaneous neuronal activity gradually decreases in glioma-infiltrated cortical regions, while neurovascular coupling becomes progressively disrupted compared to uninvolved cortex. Over time, mice develop diverse patterns of high amplitude discharges and eventually generalized seizures that appear to originate at the tumors' infiltrative margins. Interictal and seizure events exhibit positive neurovascular coupling in uninfiltrated cortex; however, glioma-infiltrated regions exhibit disrupted hemodynamic responses driving seizure-evoked hypoxia. These results reveal a landscape of complex physiological interactions occurring during glioma progression and present new opportunities for exploring novel biomarkers and therapeutic targets.
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Affiliation(s)
- Mary Katherine Montgomery
- Laboratory for Functional Optical Imaging, Zuckerman Mind Brain Behavior Institute, Departments of Biomedical Engineering and Radiology, Columbia University, New York, NY 10027, USA
| | - Sharon H Kim
- Laboratory for Functional Optical Imaging, Zuckerman Mind Brain Behavior Institute, Departments of Biomedical Engineering and Radiology, Columbia University, New York, NY 10027, USA
| | - Athanassios Dovas
- Department of Pathology and Cell Biology, Irving Cancer Research Center, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Hanzhi T Zhao
- Laboratory for Functional Optical Imaging, Zuckerman Mind Brain Behavior Institute, Departments of Biomedical Engineering and Radiology, Columbia University, New York, NY 10027, USA
| | - Alexander R Goldberg
- Department of Pathology and Cell Biology, Irving Cancer Research Center, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Weihao Xu
- Laboratory for Functional Optical Imaging, Zuckerman Mind Brain Behavior Institute, Departments of Biomedical Engineering and Radiology, Columbia University, New York, NY 10027, USA
| | - Alexis J Yagielski
- Laboratory for Functional Optical Imaging, Zuckerman Mind Brain Behavior Institute, Departments of Biomedical Engineering and Radiology, Columbia University, New York, NY 10027, USA
| | - Morgan K Cambareri
- Laboratory for Functional Optical Imaging, Zuckerman Mind Brain Behavior Institute, Departments of Biomedical Engineering and Radiology, Columbia University, New York, NY 10027, USA
| | - Kripa B Patel
- Laboratory for Functional Optical Imaging, Zuckerman Mind Brain Behavior Institute, Departments of Biomedical Engineering and Radiology, Columbia University, New York, NY 10027, USA
| | - Angeliki Mela
- Department of Pathology and Cell Biology, Irving Cancer Research Center, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Nelson Humala
- Department of Pathology and Cell Biology, Irving Cancer Research Center, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - David N Thibodeaux
- Laboratory for Functional Optical Imaging, Zuckerman Mind Brain Behavior Institute, Departments of Biomedical Engineering and Radiology, Columbia University, New York, NY 10027, USA
| | - Mohammed A Shaik
- Laboratory for Functional Optical Imaging, Zuckerman Mind Brain Behavior Institute, Departments of Biomedical Engineering and Radiology, Columbia University, New York, NY 10027, USA
| | - Ying Ma
- Laboratory for Functional Optical Imaging, Zuckerman Mind Brain Behavior Institute, Departments of Biomedical Engineering and Radiology, Columbia University, New York, NY 10027, USA
| | - Jack Grinband
- Department of Psychiatry, New York State Psychiatric Institute, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Daniel S Chow
- Department of Radiological Sciences, University of California, Irvine, Orange, CA 92868, USA
| | - Catherine Schevon
- Department of Neurology, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Peter Canoll
- Department of Pathology and Cell Biology, Irving Cancer Research Center, Columbia University Irving Medical Center, New York, NY 10032, USA.
| | - Elizabeth M C Hillman
- Laboratory for Functional Optical Imaging, Zuckerman Mind Brain Behavior Institute, Departments of Biomedical Engineering and Radiology, Columbia University, New York, NY 10027, USA.
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212
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Early AN, Gorman AA, Van Eldik LJ, Bachstetter AD, Morganti JM. Effects of advanced age upon astrocyte-specific responses to acute traumatic brain injury in mice. J Neuroinflammation 2020; 17:115. [PMID: 32290848 PMCID: PMC7158022 DOI: 10.1186/s12974-020-01800-w] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Accepted: 04/01/2020] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND Older-age individuals are at the highest risk for disability from a traumatic brain injury (TBI). Astrocytes are the most numerous glia in the brain, necessary for brain function, yet there is little known about unique responses of astrocytes in the aged-brain following TBI. METHODS Our approach examined astrocytes in young adult, 4-month-old, versus aged, 18-month-old mice, at 1, 3, and 7 days post-TBI. We selected these time points to span the critical period in the transition from acute injury to presumably irreversible tissue damage and disability. Two approaches were used to define the astrocyte contribution to TBI by age interaction: (1) tissue histology and morphological phenotyping, and (2) transcriptomics on enriched astrocytes from the injured brain. RESULTS Aging was found to have a profound effect on the TBI-induced loss of astrocyte function needed for maintaining water transport and edema-namely, aquaporin-4. The aged brain also demonstrated a progressive exacerbation of astrogliosis as a function of time after injury. Moreover, clasmatodendrosis, an underrecognized astrogliopathy, was found to be significantly increased in the aged brain, but not in the young brain. As a function of TBI, we observed a transitory refraction in the number of these astrocytes, which rebounded by 7 days post-injury in the aged brain. Transcriptomic data demonstrated disproportionate changes in genes attributed to reactive astrocytes, inflammatory response, complement pathway, and synaptic support in aged mice following TBI compared to young mice. Additionally, our data highlight that TBI did not evoke a clear alignment with the previously defined "A1/A2" dichotomy of reactive astrogliosis. CONCLUSIONS Overall, our findings point toward a progressive phenotype of aged astrocytes following TBI that we hypothesize to be maladaptive, shedding new insights into potentially modifiable astrocyte-specific mechanisms that may underlie increased fragility of the aged brain to trauma.
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Affiliation(s)
- Alexandria N Early
- Sanders-Brown Center on Aging, University of Kentucky, Room 433, Sanders-Brown Bldg., 800 S. Limestone Street, Lexington, KY, 40536, USA.,Department of Neuroscience, University of Kentucky, Lexington, KY, 40536, USA
| | - Amy A Gorman
- Sanders-Brown Center on Aging, University of Kentucky, Room 433, Sanders-Brown Bldg., 800 S. Limestone Street, Lexington, KY, 40536, USA
| | - Linda J Van Eldik
- Sanders-Brown Center on Aging, University of Kentucky, Room 433, Sanders-Brown Bldg., 800 S. Limestone Street, Lexington, KY, 40536, USA.,Department of Neuroscience, University of Kentucky, Lexington, KY, 40536, USA.,Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, KY, 40536, USA
| | - Adam D Bachstetter
- Sanders-Brown Center on Aging, University of Kentucky, Room 433, Sanders-Brown Bldg., 800 S. Limestone Street, Lexington, KY, 40536, USA.,Department of Neuroscience, University of Kentucky, Lexington, KY, 40536, USA.,Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, KY, 40536, USA
| | - Josh M Morganti
- Sanders-Brown Center on Aging, University of Kentucky, Room 433, Sanders-Brown Bldg., 800 S. Limestone Street, Lexington, KY, 40536, USA. .,Department of Neuroscience, University of Kentucky, Lexington, KY, 40536, USA. .,Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, KY, 40536, USA.
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213
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MacAulay N. Molecular mechanisms of K + clearance and extracellular space shrinkage-Glia cells as the stars. Glia 2020; 68:2192-2211. [PMID: 32181522 DOI: 10.1002/glia.23824] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Revised: 02/28/2020] [Accepted: 03/04/2020] [Indexed: 12/17/2022]
Abstract
Neuronal signaling in the central nervous system (CNS) associates with release of K+ into the extracellular space resulting in transient increases in [K+ ]o . This elevated K+ is swiftly removed, in part, via uptake by neighboring glia cells. This process occurs in parallel to the [K+ ]o elevation and glia cells thus act as K+ sinks during the neuronal activity, while releasing it at the termination of the pulse. The molecular transport mechanisms governing this glial K+ absorption remain a point of debate. Passive distribution of K+ via Kir4.1-mediated spatial buffering of K+ has become a favorite within the glial field, although evidence for a quantitatively significant contribution from this ion channel to K+ clearance from the extracellular space is sparse. The Na+ /K+ -ATPase, but not the Na+ /K+ /Cl- cotransporter, NKCC1, shapes the activity-evoked K+ transient. The different isoform combinations of the Na+ /K+ -ATPase expressed in glia cells and neurons display different kinetic characteristics and are thereby distinctly geared toward their temporal and quantitative contribution to K+ clearance. The glia cell swelling occurring with the K+ transient was long assumed to be directly associated with K+ uptake and/or AQP4, although accumulating evidence suggests that they are not. Rather, activation of bicarbonate- and lactate transporters appear to lead to glial cell swelling via the activity-evoked alkaline transient, K+ -mediated glial depolarization, and metabolic demand. This review covers evidence, or lack thereof, accumulated over the last half century on the molecular mechanisms supporting activity-evoked K+ and extracellular space dynamics.
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Affiliation(s)
- Nanna MacAulay
- Department of Neuroscience, University of Copenhagen, Copenhagen, Denmark
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214
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Lisjak M, Potokar M, Zorec R, Jorgačevski J. Indirect Role of AQP4b and AQP4d Isoforms in Dynamics of Astrocyte Volume and Orthogonal Arrays of Particles. Cells 2020; 9:cells9030735. [PMID: 32192013 PMCID: PMC7140617 DOI: 10.3390/cells9030735] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Revised: 03/10/2020] [Accepted: 03/13/2020] [Indexed: 01/10/2023] Open
Abstract
Water channel aquaporin 4 (AQP4) plays a key role in the regulation of water homeostasis in the central nervous system (CNS). It is predominantly expressed in astrocytes lining blood–brain and blood–liquor boundaries. AQP4a (M1), AQP4c (M23), and AQP4e, present in the plasma membrane, participate in the cell volume regulation of astrocytes. The function of their splicing variants, AQP4b and AQP4d, predicted to be present in the cytoplasm, is unknown. We examined the cellular distribution of AQP4b and AQP4d in primary rat astrocytes and their role in cell volume regulation. The AQP4b and AQP4d isoforms exhibited extensive cytoplasmic localization in early and late endosomes/lysosomes and in the Golgi apparatus. Neither isoform localized to orthogonal arrays of particles (OAPs) in the plasma membrane. The overexpression of AQP4b and AQP4d isoforms in isoosmotic conditions reduced the density of OAPs; in hypoosmotic conditions, they remained absent from OAPs. In hypoosmotic conditions, the AQP4d isoform was significantly redistributed to early endosomes, which correlated with the increased trafficking of AQP4-laden vesicles. The overexpression of AQP4d facilitated the kinetics of cell swelling, without affecting the regulatory volume decrease. Therefore, although they reside in the cytoplasm, AQP4b and AQP4d isoforms may play an indirect role in astrocyte volume changes.
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Affiliation(s)
- Marjeta Lisjak
- Laboratory of Neuroendocrinology–Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloška 4, 1000 Ljubljana, Slovenia; (M.L.); (M.P.); (R.Z.)
| | - Maja Potokar
- Laboratory of Neuroendocrinology–Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloška 4, 1000 Ljubljana, Slovenia; (M.L.); (M.P.); (R.Z.)
- Celica Biomedical, Tehnološki park 24, 1000 Ljubljana, Slovenia
| | - Robert Zorec
- Laboratory of Neuroendocrinology–Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloška 4, 1000 Ljubljana, Slovenia; (M.L.); (M.P.); (R.Z.)
- Celica Biomedical, Tehnološki park 24, 1000 Ljubljana, Slovenia
| | - Jernej Jorgačevski
- Laboratory of Neuroendocrinology–Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloška 4, 1000 Ljubljana, Slovenia; (M.L.); (M.P.); (R.Z.)
- Celica Biomedical, Tehnološki park 24, 1000 Ljubljana, Slovenia
- Correspondence: ; Tel.: +38615437081
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215
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Wang C, Wu Q, Wang Z, Hu L, Marshall C, Xiao M. Aquaporin 4 knockout increases complete freund's adjuvant-induced spinal central sensitization. Brain Res Bull 2020; 156:58-66. [DOI: 10.1016/j.brainresbull.2020.01.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2019] [Revised: 12/30/2019] [Accepted: 01/03/2020] [Indexed: 01/07/2023]
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216
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Vandebroek A, Yasui M. Regulation of AQP4 in the Central Nervous System. Int J Mol Sci 2020; 21:E1603. [PMID: 32111087 PMCID: PMC7084855 DOI: 10.3390/ijms21051603] [Citation(s) in RCA: 86] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 02/21/2020] [Accepted: 02/21/2020] [Indexed: 12/26/2022] Open
Abstract
Aquaporin-4 (AQP4) is the main water channel protein expressed in the central nervous system (CNS). AQP4 is densely expressed in astrocyte end-feet, and is an important factor in CNS water and potassium homeostasis. Changes in AQP4 activity and expression have been implicated in several CNS disorders, including (but not limited to) epilepsy, edema, stroke, and glioblastoma. For this reason, many studies have been done to understand the various ways in which AQP4 is regulated endogenously, and could be regulated pharmaceutically. In particular, four regulatory methods have been thoroughly studied; regulation of gene expression via microRNAs, regulation of AQP4 channel gating/trafficking via phosphorylation, regulation of water permeability using heavy metal ions, and regulation of water permeability using small molecule inhibitors. A major challenge when studying AQP4 regulation is inter-method variability. A compound or phosphorylation which shows an inhibitory effect in vitro may show no effect in a different in vitro method, or even show an increase in AQP4 expression in vivo. Although a large amount of variability exists between in vitro methods, some microRNAs, heavy metal ions, and two small molecule inhibitors, acetazolamide and TGN-020, have shown promise in the field of AQP4 regulation.
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Affiliation(s)
- Arno Vandebroek
- Department of Pharmacology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku, Tokyo 160-8582, Japan;
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217
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Palazzo C, Abbrescia P, Valente O, Nicchia GP, Banitalebi S, Amiry-Moghaddam M, Trojano M, Frigeri A. Tissue Distribution of the Readthrough Isoform of AQP4 Reveals a Dual Role of AQP4ex Limited to CNS. Int J Mol Sci 2020; 21:ijms21041531. [PMID: 32102323 PMCID: PMC7073200 DOI: 10.3390/ijms21041531] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Revised: 02/14/2020] [Accepted: 02/19/2020] [Indexed: 02/06/2023] Open
Abstract
Translational readthrough (TRT) of aquaporin-4 (AQP4) has remarkably expanded the importance of this new post-transcriptional mechanism, as well as the regulation potential of AQP4. The TRT isoform of AQP4, named AQP4ex, is central for both AQP4 polarization and water channel activity in the central nervous system (CNS). Here we evaluate the relevance of the TRT mechanism by analyzing whether AQP4ex is also expressed in peripheral tissues and whether the expression of AQP4ex is necessary for its polarized expression as it occurs in perivascular astrocyte processes. To this purpose, AQP4ex null mice were used, and analysis was performed by immunolocalization and immunoblot. The results demonstrate that AQP4ex is expressed in kidney, stomach, trachea and skeletal muscle with the same localization pattern as the canonical AQP4 isoforms. AQP4ex protein levels vary from 6% to about 13% of the total AQP4 protein levels in peripheral tissues. Immunogold electron microscopy experiments demonstrated the localization of AQP4ex at the astrocytic endfeet, and experiments conducted on AQP4ex null mice CNS confirmed that the expression of AQP4ex is necessary for anchoring of the perivascular AQP4. Without the readthrough isoform, AQP4 assemblies are mis-localized, being uniformly distributed on the astrocyte processes facing the neuropile. No alteration of AQP4 polarization was found in AQP4ex null kidney, stomach, trachea or skeletal muscle, suggesting that AQP4ex does not have a role for proper membrane localization of AQP4 in peripheral tissues. We conclude that a dual role for AQP4ex is limited to the CNS.
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Affiliation(s)
- Claudia Palazzo
- Department of Basic Medical Sciences, Neurosciences and Sense Organs, School of Medicine, University of Bari Aldo Moro, 70124 Bari, Italy; (C.P.); (O.V.); (M.T.)
| | - Pasqua Abbrescia
- Department of Basic Medical Sciences, Neurosciences and Sense Organs, School of Medicine, University of Bari Aldo Moro, 70124 Bari, Italy; (C.P.); (O.V.); (M.T.)
| | - Onofrio Valente
- Department of Basic Medical Sciences, Neurosciences and Sense Organs, School of Medicine, University of Bari Aldo Moro, 70124 Bari, Italy; (C.P.); (O.V.); (M.T.)
| | - Grazia Paola Nicchia
- Department of Bioscience, Biotechnology and Biopharmaceutics, University of Bari Aldo Moro, 70125 Bari, Italy;
| | - Shervin Banitalebi
- Division of Anatomy, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, 0317 Oslo, Norway; (S.B.); (M.A.-M.)
| | - Mahmood Amiry-Moghaddam
- Division of Anatomy, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, 0317 Oslo, Norway; (S.B.); (M.A.-M.)
| | - Maria Trojano
- Department of Basic Medical Sciences, Neurosciences and Sense Organs, School of Medicine, University of Bari Aldo Moro, 70124 Bari, Italy; (C.P.); (O.V.); (M.T.)
| | - Antonio Frigeri
- Department of Basic Medical Sciences, Neurosciences and Sense Organs, School of Medicine, University of Bari Aldo Moro, 70124 Bari, Italy; (C.P.); (O.V.); (M.T.)
- Correspondence:
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218
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The Pattern of AQP4 Expression in the Ageing Human Brain and in Cerebral Amyloid Angiopathy. Int J Mol Sci 2020; 21:ijms21041225. [PMID: 32059400 PMCID: PMC7072949 DOI: 10.3390/ijms21041225] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2019] [Revised: 02/03/2020] [Accepted: 02/10/2020] [Indexed: 02/06/2023] Open
Abstract
In the absence of lymphatics, fluid and solutes such as amyloid-β (Aβ) are eliminated from the brain along basement membranes in the walls of cerebral capillaries and arteries—the Intramural Peri-Arterial Drainage (IPAD) pathway. IPAD fails with age and insoluble Aβ is deposited as plaques in the brain and in IPAD pathways as cerebral amyloid angiopathy (CAA); fluid accumulates in the white matter as reflected by hyperintensities (WMH) on MRI. Within the brain, fluid uptake by astrocytes is regulated by aquaporin 4 (AQP4). We test the hypothesis that expression of astrocytic AQP4 increases in grey matter and decreases in white matter with onset of CAA. AQP4 expression was quantitated by immunocytochemistry and confocal microscopy in post-mortem occipital grey and white matter from young and old non-demented human brains, in CAA and in WMH. Results: AQP4 expression tended to increase with normal ageing but AQP4 expression in severe CAA was significantly reduced when compared to moderate CAA (p = 0.018). AQP4 expression tended to decline in the white matter with CAA and WMH, both of which are associated with impaired IPAD. Adjusting the level of AQP4 activity may be a valid therapeutic target for restoring homoeostasis in the brain as IPAD fails with age and CAA.
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219
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Uncoupling of the Astrocyte Syncytium Differentially Affects AQP4 Isoforms. Cells 2020; 9:cells9020382. [PMID: 32046059 PMCID: PMC7072498 DOI: 10.3390/cells9020382] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Revised: 01/29/2020] [Accepted: 02/04/2020] [Indexed: 11/25/2022] Open
Abstract
The water channel protein aquaporin-4 (AQP4) and the gap junction forming proteins connexin-43 (Cx43) and connexin-30 (Cx30) are astrocytic proteins critically involved in brain water and ion homeostasis. While AQP4 is mainly involved in water flux across the astrocytic endfeet membranes, astrocytic gap junctions provide syncytial coupling allowing intercellular exchange of water, ions, and other molecules. We have previously shown that mice with targeted deletion of Aqp4 display enhanced gap junctional coupling between astrocytes. Here, we investigate whether uncoupling of the astrocytic syncytium by deletion of the astrocytic connexins Cx43 and Cx30 affects AQP4 membrane localization and expression. By using quantitative immunogold cytochemistry, we show that deletion of astrocytic connexins leads to a substantial reduction of perivascular AQP4, concomitant with a down-regulation of total AQP4 protein and mRNA. Isoform expression analysis shows that while the level of the predominant AQP4 M23 isoform is reduced in Cx43/Cx30 double deficient hippocampal astrocytes, the levels of M1, and the alternative translation AQP4ex isoform protein levels are increased. These findings reveal a complex interdependence between AQP4 and connexins, which are both significantly involved in homeostatic functions and astrogliopathologies.
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220
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Zhang W, Dong M, Dong H, Wang W, Sun W, Hao Y, Jiao Y, Cui L, Jiao J. Reduced sarcolemmal aquaporin 4 expression can support the differential diagnosis of neuromyelitis optica spectrum disorders. J Neuroimmunol 2020; 339:577121. [DOI: 10.1016/j.jneuroim.2019.577121] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2019] [Revised: 10/31/2019] [Accepted: 11/25/2019] [Indexed: 11/28/2022]
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221
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Valenza M, Facchinetti R, Steardo L, Scuderi C. Altered Waste Disposal System in Aging and Alzheimer's Disease: Focus on Astrocytic Aquaporin-4. Front Pharmacol 2020; 10:1656. [PMID: 32063858 PMCID: PMC7000422 DOI: 10.3389/fphar.2019.01656] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Accepted: 12/17/2019] [Indexed: 12/15/2022] Open
Abstract
Among the diverse cell types included in the general population named glia, astrocytes emerge as being the focus of a growing body of research aimed at characterizing their heterogeneous and complex functions. Alterations of both their morphology and activities have been linked to a variety of neurological diseases. One crucial physiological need satisfied by astrocytes is the cleansing of the cerebral tissue from waste molecules. Several data demonstrate that aquaporin-4 (AQP-4), a protein expressed by astrocytes, is crucially important for facilitating the removal of waste products from the brain. Aquaporins are water channels found in all district of the human organism and the most abundant isoform in the brain is AQP-4. This protein is involved in a myriad of astrocytic activities, including calcium signal transduction, potassium buffering, synaptic plasticity, astrocyte migration, glial scar formation and neuroinflammation. The highest density of AQP-4 is found at the astrocytic domains closest to blood vessels, the endfeet that envelop brain vessels, with low to zero expression in other astrocytic membrane regions. Increased AQP-4 expression and loss of polarization have recently been documented in altered physiological conditions. Here we review the latest findings related to aging and Alzheimer’s disease (AD) on this topic, as well as the available knowledge on pharmacological tools to target AQP-4.
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Affiliation(s)
- Marta Valenza
- Department Physiology and Pharmacology "V. Erspamer", Sapienza University of Rome, Rome, Italy.,Epitech Group SpA, Saccolongo, Italy
| | - Roberta Facchinetti
- Department Physiology and Pharmacology "V. Erspamer", Sapienza University of Rome, Rome, Italy
| | - Luca Steardo
- Università Telematica Giustino Fortunato, Benevento, Italy
| | - Caterina Scuderi
- Department Physiology and Pharmacology "V. Erspamer", Sapienza University of Rome, Rome, Italy
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222
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Cavallo S. Immune-mediated genesis of multiple sclerosis. J Transl Autoimmun 2020; 3:100039. [PMID: 32743522 PMCID: PMC7388381 DOI: 10.1016/j.jtauto.2020.100039] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Revised: 01/03/2020] [Accepted: 01/05/2020] [Indexed: 12/14/2022] Open
Abstract
Multiple sclerosis (MS) is widely acknowledged to be an autoimmune disease affecting the neuronal myelin structure of the CNS. Autoantigens recognized as the target of this autoimmune process are: myelin basal protein, anti-proteolipid protein, antimyelin-associated glycoprotein and antimyelin-based oligodendrocytic basic protein. Ample evidence supports the idea of a dysregulation of immunological tolerance towards self-antigens of neuronal myelin structure triggered by one or more viral or bacterial microbial agents in predisposed HLA gene subjects. Genetic predisposition to MS has been highlighted by numerous studies associating the disease to specific HLA haplotypes. Moreover, a wide range of evidence supports the fact that MS may be consequence of one or more viral or bacterial infections such as measles virus, EBV, HHV6, HZV, Chlamydia pneumoniae, Helicobacter Pylori, and other microbial agents. Microbiota elements also seems to have a role on the determinism of the disease as a pathogenic or protective factor. The autoimmune pathogenetic process could arise when a molecular mimicry between a foreign microbial antigen and an auto-antigen occurs in an HLA gene subject competent for that particular antigen. The antigen-presenting cells in this case would induce the activation of a specific Th clone causing a cross-reaction between a foreign antigen and an autoantigen resulting in an autoimmune response. A multifactorial ethiopathogenetic model based on immunomediation is a reliable hypothesis for multiple sclerosis. Evidence found in the scientific literature makes it possible to reconstruct this etiopathogenetic hypothesis for MS. HLA gene predisposition, correlation with infections, molecular mimicry and other immunological data are reported.
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Affiliation(s)
- Salvatore Cavallo
- Expert Doctor in Non-Conventional Medicine, Professor and Member of the Board of the MMS, MMS (Medicina di Modulazione Dei Sistemi) Roma, Salvatore Cavallo Via G.B. Pergolesi, 28, 75100, Matera, Italy
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223
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Hindeya Gebreyesus H, Gebrehiwot Gebremichael T. The Potential Role of Astrocytes in Parkinson's Disease (PD). Med Sci (Basel) 2020; 8:E7. [PMID: 32012713 PMCID: PMC7151567 DOI: 10.3390/medsci8010007] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Revised: 08/08/2019] [Accepted: 08/09/2019] [Indexed: 12/11/2022] Open
Abstract
Astrocytes are multi-functional cells, now recognized as critical participants in many brain functions. They play a critical physiological role in the clearance of neurotransmitters, such as glutamate and gamma-aminobutyric acid (GABA), and in the regulation of K+ from the space of synaptic clefts. Astrocytes also express the excitatory amino acid transporters (EAATs) and aquaporin-4 (AQP4) water channel, which are involved in both physiological functions and neurodegenerative diseases (ND). Some of the ND are the Alzheimer's (AD), Huntington's (HD), Parkinson's diseases (PD), Cerebral edema, amyotrophic lateral sclerosis (ALS), and epilepsy pathological conditions in specific regions of the CNS. Parkinson's disease is the second most common age-related neurodegenerative disorder, characterized by degeneration of dopaminergic neurons of the substantia nigra pars compacta (SNpc). These project to the striatum, forming an important pathway within the basal ganglia. Mostly, PD has no clear etiology, and the mechanism of dopaminergic (DA) neuron loss is not well illustrated. The results of various studies suggest that astrocytes are involved in the pathophysiology of PD. Evidence has shown that the down-regulation of EAAT-2/GLT-1 and AQP4 expression is associated with PD pathogenesis. However, controversial results were reported in different experimental studies about the expression and function of EAAT-2/GLT-1 and AQP4, as well as their colocalization in different brain regions, and their involvement in PD development. Therefore, under neurological disorders, Parkinson's disease is related to the genetic and phenotypic change of astrocytes' biology. In this review, the authors summarized recent their research findings, which revealed the involvement of EAAT-2/GLT-1 and AQP4 expression, the physical interaction between EAAT-2/GLT-1 and AQP4 in astrocyte function, and their potential role in the development of PD in SNpc and Subthalamic nucleus (STN) of the basal ganglia nuclei.
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Affiliation(s)
- Hiluf Hindeya Gebreyesus
- School of Medicine, Biomedical Sciences, College of Health Sciences, Mekelle University, P.O. Box: 1871 Mekelle, Tigray, Ethiopia
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224
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Yan J, Wang Y, Miao H, Kwapong WR, Lu Y, Ma Q, Chen W, Tu Y, Liu X. Alterations in the Brain Structure and Functional Connectivity in Aquaporin-4 Antibody-Positive Neuromyelitis Optica Spectrum Disorder. Front Neurosci 2020; 13:1362. [PMID: 32009872 PMCID: PMC6971221 DOI: 10.3389/fnins.2019.01362] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Accepted: 12/02/2019] [Indexed: 11/13/2022] Open
Abstract
Purpose To investigate the mechanisms underlying the gray matter volume (GMV) and functional connectivity (FC) changes in aquaporin-4 antibody-positive neuromyelitis optica spectrum disorder (NMOSD) patients. Methods This cross-sectional study consisted of 21 patients with aquaporin-4 antibody-positive NMOSD and 22 age- and sex-matched healthy controls. All participants underwent cerebral magnetic resonance imaging and testing each individual’s visual acuity was done. Results Neuromyelitis optica spectrum disorder patients showed significantly reduced GMV in the left calcarine, left thalamus and right lingual gyrus of the NMOSD patients when compared to HC (P < 0.05). NMOSD patients showed significantly decreased FC values (P < 0.05) in both the left and right calcarine, right lingual gyrus and left thalamus, respectively, when compared to HC. We also observed a positive correlation between the FC values of the left thalamus, bilateral calcarine gyrus and the visual acuity, respectively (P < 0.05). Furthermore, a negative association was seen between the duration of the disease, frequency of optic neuritis, and the FC values in the lingual gyrus, bilateral calcarine gyrus, and right lingual gyrus, respectively (P < 0.05). Conclusion Reduced visual acuity and frequency of optic neuritis are associated with alterations in the GMV and FC in NMOSD. Our current study, which provides imaging evidence on the impairment involved in NMOSD, sheds light on pathophysiological responses of optic neuritis attack on the brain especially on the visual network.
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Affiliation(s)
- Jueyue Yan
- Department of Neurology, The Second Affiliated Hospital & Yuying Children's Hospital, Wenzhou Medical University, Wenzhou, China
| | - Yu Wang
- China-USA Neuroimaging Research Institute, Department of Radiology, The Second Affiliated Hospital & Yuying Children's Hospital, Wenzhou Medical University, Wenzhou, China
| | - Hanpei Miao
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, China
| | | | - Yi Lu
- China-USA Neuroimaging Research Institute, Department of Radiology, The Second Affiliated Hospital & Yuying Children's Hospital, Wenzhou Medical University, Wenzhou, China
| | - Qingkai Ma
- Department of Opthalmology, The First Affiliated Hospital of Anhui Medical University, Hefei, China
| | - Wei Chen
- Department of Psychiatry, Sir Run Run Shaw Hospital, Collaborative Innovation Center for Brain Science, Zhejiang University School of Medicine, Hangzhou, China
| | - Yunhai Tu
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, China
| | - Xiaozheng Liu
- China-USA Neuroimaging Research Institute, Department of Radiology, The Second Affiliated Hospital & Yuying Children's Hospital, Wenzhou Medical University, Wenzhou, China
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Shan W, Chen W, Zhao X, Pei A, Chen M, Yu Y, Zheng Y, Zhu S. Long noncoding RNA TUG1 contributes to cerebral ischaemia/reperfusion injury by sponging mir-145 to up-regulate AQP4 expression. J Cell Mol Med 2020; 24:250-259. [PMID: 31709761 PMCID: PMC6933375 DOI: 10.1111/jcmm.14712] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Revised: 07/26/2019] [Accepted: 08/29/2019] [Indexed: 12/17/2022] Open
Abstract
Emerging studies have shown that long noncoding RNA (lncRNA) TUG1 (taurine-up-regulated gene 1) plays critical roles in multiple biological processes. However, the expression and function of lncRNA TUG1 in cerebral ischaemia/reperfusion injury have not been reported yet. In this study, we found that LncRNA TUG1 expression was significantly up-regulated in cultured MA-C cells exposed to OGD/R injury, while similar results were also observed in MCAO model. Mechanistically, knockdown of TUG1 decreased lactate dehydrogenase levels and the ratio of apoptotic cells and promoted cell survival in vitro. Moreover, knockdown of TUG1 decreased AQP4 (encoding aquaporin 4) expression to attenuate OGD/R injury. TUG1 could interact directly with miR-145, and down-regulation of miR-145 could efficiently reverse the function of TUG1 siRNA on AQP4 expression. Finally, the TUG1 shRNA reduced the infarction area and cell apoptosis in I/R mouse brains in vivo. In summary, our results suggested that lncRNA TUG1 may function as a competing endogenous RNA (ceRNA) for miR-145 to induce cell damage, possibly providing a new therapeutic target in cerebral ischaemia/reperfusion injury.
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Affiliation(s)
- Weifeng Shan
- Department of AnesthesiologyThe 1st Affiliated HospitalSchool of MedicineZhejiang UniversityHangzhouChina
| | - Wei Chen
- Cancer Institute of Integrated traditional Chinese and Western MedicineZhejiang Academy of Traditional Chinese MedicineTongde hospital of Zhejiang ProvinceHangzhouChina
| | - Xian Zhao
- Department of AnesthesiologyThe 1st Affiliated HospitalSchool of MedicineZhejiang UniversityHangzhouChina
| | - Aijie Pei
- Department of AnesthesiologyThe 1st Affiliated HospitalSchool of MedicineZhejiang UniversityHangzhouChina
| | - Manli Chen
- Department of AnesthesiologyThe 1st Affiliated HospitalSchool of MedicineZhejiang UniversityHangzhouChina
| | - Yang Yu
- Department of AnesthesiologyThe 1st Affiliated HospitalSchool of MedicineZhejiang UniversityHangzhouChina
| | - Yueying Zheng
- Department of AnesthesiologyThe 1st Affiliated HospitalSchool of MedicineZhejiang UniversityHangzhouChina
| | - Shengmei Zhu
- Department of AnesthesiologyThe 1st Affiliated HospitalSchool of MedicineZhejiang UniversityHangzhouChina
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226
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Walch E, Murphy TR, Cuvelier N, Aldoghmi M, Morozova C, Donohue J, Young G, Samant A, Garcia S, Alvarez C, Bilas A, Davila D, Binder DK, Fiacco TA. Astrocyte-Selective Volume Increase in Elevated Extracellular Potassium Conditions Is Mediated by the Na +/K + ATPase and Occurs Independently of Aquaporin 4. ASN Neuro 2020; 12:1759091420967152. [PMID: 33092407 PMCID: PMC7586494 DOI: 10.1177/1759091420967152] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Accepted: 09/23/2020] [Indexed: 12/26/2022] Open
Abstract
Astrocytes and neurons have been shown to swell across a variety of different conditions, including increases in extracellular potassium concentration (^[K+]o). The mechanisms involved in the coupling of K+ influx to water movement into cells leading to cell swelling are not well understood and remain controversial. Here, we set out to determine the effects of ^[K+]o on rapid volume responses of hippocampal CA1 pyramidal neurons and stratum radiatum astrocytes using real-time confocal volume imaging. First, we found that elevating [K+]o within a physiological range (to 6.5 mM and 10.5 mM from a baseline of 2.5 mM), and even up to pathological levels (26 mM), produced dose-dependent increases in astrocyte volume, with absolutely no effect on neuronal volume. In the absence of compensating for addition of KCl by removal of an equal amount of NaCl, neurons actually shrank in ^[K+]o, while astrocytes continued to exhibit rapid volume increases. Astrocyte swelling in ^[K+]o was not dependent on neuronal firing, aquaporin 4, the inwardly rectifying potassium channel Kir 4.1, the sodium bicarbonate cotransporter NBCe1, , or the electroneutral cotransporter, sodium-potassium-chloride cotransporter type 1 (NKCC1), but was significantly attenuated in 1 mM barium chloride (BaCl2) and by the Na+/K+ ATPase inhibitor ouabain. Effects of 1 mM BaCl2 and ouabain applied together were not additive and, together with reports that BaCl2 can inhibit the NKA at high concentrations, suggests a prominent role for the astrocyte NKA in rapid astrocyte volume increases occurring in ^[K+]o. These findings carry important implications for understanding mechanisms of cellular edema, regulation of the brain extracellular space, and brain tissue excitability.
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Affiliation(s)
- Erin Walch
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, Riverside, United States
- Center for Glial-Neuronal Interactions, University of California, Riverside, Riverside, United States
| | - Thomas R. Murphy
- Department of Molecular, Cell and Systems Biology, University of California, Riverside, Riverside, United States
| | - Nicholas Cuvelier
- Department of Molecular, Cell and Systems Biology, University of California, Riverside, Riverside, United States
- Interdepartmental Graduate Program in Neuroscience, University of California, Riverside, Riverside, United States
| | - Murad Aldoghmi
- Department of Molecular, Cell and Systems Biology, University of California, Riverside, Riverside, United States
| | - Cristine Morozova
- Department of Molecular, Cell and Systems Biology, University of California, Riverside, Riverside, United States
- Undergraduate Major in Neuroscience, University of California, Riverside, Riverside, United States
| | - Jordan Donohue
- Department of Molecular, Cell and Systems Biology, University of California, Riverside, Riverside, United States
- Interdepartmental Graduate Program in Neuroscience, University of California, Riverside, Riverside, United States
| | - Gaby Young
- Department of Molecular, Cell and Systems Biology, University of California, Riverside, Riverside, United States
- Undergraduate Major in Neuroscience, University of California, Riverside, Riverside, United States
| | - Anuja Samant
- Department of Molecular, Cell and Systems Biology, University of California, Riverside, Riverside, United States
- Undergraduate Major in Neuroscience, University of California, Riverside, Riverside, United States
| | - Stacy Garcia
- Department of Molecular, Cell and Systems Biology, University of California, Riverside, Riverside, United States
- Undergraduate Major in Neuroscience, University of California, Riverside, Riverside, United States
| | - Camila Alvarez
- Department of Molecular, Cell and Systems Biology, University of California, Riverside, Riverside, United States
- Undergraduate Major in Neuroscience, University of California, Riverside, Riverside, United States
| | - Alex Bilas
- Department of Molecular, Cell and Systems Biology, University of California, Riverside, Riverside, United States
- Interdepartmental Graduate Program in Neuroscience, University of California, Riverside, Riverside, United States
| | - David Davila
- Department of Molecular, Cell and Systems Biology, University of California, Riverside, Riverside, United States
| | - Devin K. Binder
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, Riverside, United States
- Center for Glial-Neuronal Interactions, University of California, Riverside, Riverside, United States
- Interdepartmental Graduate Program in Neuroscience, University of California, Riverside, Riverside, United States
| | - Todd A. Fiacco
- Center for Glial-Neuronal Interactions, University of California, Riverside, Riverside, United States
- Department of Molecular, Cell and Systems Biology, University of California, Riverside, Riverside, United States
- Interdepartmental Graduate Program in Neuroscience, University of California, Riverside, Riverside, United States
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227
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Jaeger V, DeMorrow S, McMillin M. The Direct Contribution of Astrocytes and Microglia to the Pathogenesis of Hepatic Encephalopathy. J Clin Transl Hepatol 2019; 7:352-361. [PMID: 31915605 PMCID: PMC6943208 DOI: 10.14218/jcth.2019.00025] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Revised: 10/07/2019] [Accepted: 10/24/2019] [Indexed: 02/06/2023] Open
Abstract
Hepatic encephalopathy is a neurological complication resulting from loss of hepatic function and is associated with poor clinical outcomes. During acute liver failure over 20% of mortality can be associated with the development of hepatic encephalopathy. In patients with liver cirrhosis, 1-year survival for those that develop overt hepatic encephalopathy is under 50%. The pathogenesis of hepatic encephalopathy is complicated due to the multiple disruptions in homeostasis that occur following a reduction in liver function. Of these, elevations of ammonia and neuroinflammation have been shown to play a significant contributing role to the development of hepatic encephalopathy. Disruption of the urea cycle following liver dysfunction leads to elevations of circulating ammonia, which enter the brain and disrupt the functioning of astrocytes. This results in dysregulation of metabolic pathways in astrocytes, oxidative stress and cerebral edema. Besides ammonia, circulating chemokines and cytokines are increased following liver injury, leading to activation of microglia and a subsequent neuroinflammatory response. The combination of astrocyte dysfunction and microglia activation are significant contributing factors to the pathogenesis of hepatic encephalopathy.
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Affiliation(s)
- Victoria Jaeger
- Baylor Scott & White Health, Department of Internal Medicine, Temple, TX, USA
| | - Sharon DeMorrow
- Texas A&M University Health Science Center, Department of Medical Physiology, Temple, TX, USA
- Central Texas Veterans Health Care System, Temple, TX, USA
- University of Texas at Austin, Dell Medical School, Department of Internal Medicine, Austin, TX, USA
- University of Texas at Austin, College of Pharmacy, Austin, TX, USA
| | - Matthew McMillin
- Texas A&M University Health Science Center, Department of Medical Physiology, Temple, TX, USA
- Central Texas Veterans Health Care System, Temple, TX, USA
- University of Texas at Austin, Dell Medical School, Department of Internal Medicine, Austin, TX, USA
- Correspondence to: Matthew McMillin, University of Texas at Austin Dell Medical School, 1601 Trinity Street, Building B, Austin, TX 78701, USA. Tel: +1-512-495-5037, Fax: +1-512-495-5839, E-mail:
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228
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Hausburg MA, Banton KL, Roman PE, Salgado F, Baek P, Waxman MJ, Tanner A, Yoder J, Bar-Or D. Effects of propofol on ischemia-reperfusion and traumatic brain injury. J Crit Care 2019; 56:281-287. [PMID: 32001426 DOI: 10.1016/j.jcrc.2019.12.021] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Revised: 12/07/2019] [Accepted: 12/24/2019] [Indexed: 12/14/2022]
Abstract
Oxidative stress exacerbates brain damage following ischemia-reperfusion and traumatic brain injury (TBI). Management of TBI and critically ill patients commonly involves use of propofol, a sedation medication that acts as a general anesthetic with inherent antioxidant properties. Here we review available evidence from animal model systems and clinical studies that propofol protects against ischemia-reperfusion injury. However, evidence of propofol toxicity in humans exists and manifests as a rare complication, "propofol infusion syndrome" (PRIS). Evidence in animal models suggests that brain injury induces expression of the p75 neurotrophin receptor (p75NTR), which is associated with proapoptotic signaling. p75NTR-mediated apoptosis of neurons is further exacerbated by propofol's superinduction of p75NTR and concomitant inhibition of neurotrophin processing. Propofol is toxic to neurons but not astrocytes, a type of glial cell. Evidence suggests that propofol protects astrocytes from oxidative stress and stimulates astroglial-mediated protection of neurons. One may speculate that in brain injury patients under sedation/anesthesia, propofol provides brain tissue protection or aids in recovery by enhancing astrocyte function. Nevertheless, our understanding of neurologic recovery versus long-term neurological sequelae leading to neurodegeneration is poor, and it is also conceivable that propofol plays a partial as yet unrecognized role in long-term impairment of the injured brain.
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Affiliation(s)
- Melissa A Hausburg
- Trauma Research Department, Swedish Medical Center, 501 E Hampden, Englewood, CO 80113, USA; Trauma Research Department, St. Anthony Hospital, 11600 W 2nd Pl, Lakewood, CO 80228, USA; Trauma Research Department, Medical City Plano, 3901 W 15th St, Plano, TX 75075, USA; Trauma Research Department, Penrose Hospital, 2222 N Nevada Ave, Colorado Springs, CO 80907, USA; Trauma Research Department, Research Medical Center, 2316 E Meyer Blvd, Kansas City, MO 64132, USA; Trauma Research Department, Wesley Medical Center, 550 N Hillside St, Wichita, KS 67214, USA
| | - Kaysie L Banton
- Trauma Research Department, Swedish Medical Center, 501 E Hampden, Englewood, CO 80113, USA
| | - Phillip E Roman
- Trauma Research Department, St. Anthony Hospital, 11600 W 2nd Pl, Lakewood, CO 80228, USA; Department of Anesthesiology, St. Anthony Hospital, Lakewood, CO 80228, USA
| | - Fernando Salgado
- Trauma Research Department, Wesley Medical Center, 550 N Hillside St, Wichita, KS 67214, USA; Department of Anesthesiology, Wesley Medical Center, Wichita, KS 67214, USA
| | - Peter Baek
- Trauma Research Department, Medical City Plano, 3901 W 15th St, Plano, TX 75075, USA; Department of Anesthesiology, Medical City Plano, Plano, TX 75075, USA
| | - Michael J Waxman
- Department of Critical Care, Research Medical Center, Kansas City, MO 64132, USA
| | - Allen Tanner
- Trauma Research Department, Penrose Hospital, 2222 N Nevada Ave, Colorado Springs, CO 80907, USA
| | - Jeffrey Yoder
- Trauma Research Department, St. Anthony Hospital, 11600 W 2nd Pl, Lakewood, CO 80228, USA; Department of Anesthesiology, St. Anthony Hospital, Lakewood, CO 80228, USA
| | - David Bar-Or
- Trauma Research Department, Swedish Medical Center, 501 E Hampden, Englewood, CO 80113, USA; Trauma Research Department, St. Anthony Hospital, 11600 W 2nd Pl, Lakewood, CO 80228, USA; Trauma Research Department, Medical City Plano, 3901 W 15th St, Plano, TX 75075, USA; Trauma Research Department, Penrose Hospital, 2222 N Nevada Ave, Colorado Springs, CO 80907, USA; Trauma Research Department, Research Medical Center, 2316 E Meyer Blvd, Kansas City, MO 64132, USA; Trauma Research Department, Wesley Medical Center, 550 N Hillside St, Wichita, KS 67214, USA; Department of Molecular Biology, Rocky Vista University, 8401 S Chambers Rd, Parker, CO 80134, USA.
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229
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Kálmán M, Oszwald E, Pócsai K. Three-plane description of astroglial populations of OVLT subdivisions in rat: Tanycyte connections to distant parts of third ventricle. J Comp Neurol 2019; 527:2793-2812. [PMID: 31045238 DOI: 10.1002/cne.24707] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Revised: 04/22/2019] [Accepted: 04/23/2019] [Indexed: 11/07/2022]
Abstract
This study demonstrates glial and gliovascular markers of organon vasculosum laminae terminalis (OVLT) in three planes. The distribution of glial markers displayed similarities to the subfornical organ. There was an inner part with vimentin- and nestin-immunopositive glia whereas GFAP and the water-channel aquaporin 4 were found at the periphery. This separation indicates different functions of the two regions. The presence of nestin may indicate stem cell-capabilities whereas aquaporin 4 has been reported to promote the osmoreceptor function. Glutamine synthetase immunoreactivity was sparse like in the area postrema and subfornical organ. The laminin and β-dystroglycan immunolabelings altered along the vessels such as in the subfornical organ indicating altering gliovascular relations. The different subdivisions of OVLT received glial processes of different origins. The posterior periventricular zone contained short vimentin-immunopositive processes from the ependyma of the adjacent surface of the third ventricle. The lateral periventricular zone received forceps-like process systems from the anterolateral part of the third ventricle. Most interestingly, the "dorsal cap" received a mixed group of long GFAP- and vimentin-immunopositive processes from a distant part of the third ventricle. The processes may have two functions: a guidance for newly produced cells like radial glia in immature brain and/or a connection between distant parts of the third ventricle and OVLT.
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Affiliation(s)
- Mihály Kálmán
- Department of Anatomy, Histology and Embryology, Semmelweis University, Budapest, Hungary
| | - Erzsébet Oszwald
- Department of Anatomy, Histology and Embryology, Semmelweis University, Budapest, Hungary
| | - Károly Pócsai
- Department of Anatomy, Histology and Embryology, Semmelweis University, Budapest, Hungary
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230
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Abstract
Despite its small size, the brain consumes 25% of the body’s energy, generating its own weight in potentially toxic proteins and biological debris each year. The brain is also the only organ lacking lymph vessels to assist in removal of interstitial waste. Over the past 50 years, a picture has been developing of the brain’s unique waste removal system. Experimental observations show cerebrospinal fluid, which surrounds the brain, enters the brain along discrete pathways, crosses a barrier into the spaces between brain cells, and flushes the tissue, carrying wastes to routes exiting the brain. Dysfunction of this cerebral waste clearance system has been demonstrated in Alzheimer’s disease, traumatic brain injury, diabetes, and stroke. The activity of the system is observed to increase during sleep. In addition to waste clearance, this circuit of flow may also deliver nutrients and neurotransmitters. Here, we review the relevant literature with a focus on transport processes, especially the potential role of diffusion and advective flows.
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231
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Xu S, Sun Q, Fan J, Jiang Y, Yang W, Cui Y, Yu Z, Jiang H, Li B. Role of Astrocytes in Post-traumatic Epilepsy. Front Neurol 2019; 10:1149. [PMID: 31798512 PMCID: PMC6863807 DOI: 10.3389/fneur.2019.01149] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2019] [Accepted: 10/14/2019] [Indexed: 12/25/2022] Open
Abstract
Traumatic brain injury, a common cause of acquired epilepsy, is typical to find necrotic cell death within the injury core. The dynamic changes in astrocytes surrounding the injury core contribute to epileptic seizures associated with intense neuronal firing. However, little is known about the molecular mechanisms that activate astrocytes during traumatic brain injury or the effect of functional changes of astrocytes on seizures. In this comprehensive review, we present our cumulated understanding of the complex neurological affection in astrocytes after traumatic brain injury. We approached the problem through describing the changes of cell morphology, neurotransmitters, biochemistry, and cytokines in astrocytes during post-traumatic epilepsy. In addition, we also discussed the relationship between dynamic changes in astrocytes and seizures and the current pharmacologic agents used for treatment. Hopefully, this review will provide a more detailed knowledge from which better therapeutic strategies can be developed to treat post-traumatic epilepsy.
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Affiliation(s)
- Songbai Xu
- Department of Neurosurgery, the First Hospital of Jilin University, Changchun, China
| | - Qihan Sun
- School of Pharmaceutical Sciences, Jilin University, Changchun, China
| | - Jie Fan
- Jilin Provincial Key Laboratory on Molecular and Chemical Genetic, The Second Hospital of Jilin University, Changchun, China
| | - Yuanyuan Jiang
- School of Pharmaceutical Sciences, Jilin University, Changchun, China
| | - Wei Yang
- Jilin Provincial Key Laboratory on Molecular and Chemical Genetic, The Second Hospital of Jilin University, Changchun, China
| | - Yifeng Cui
- Department of Pediatrics, Yanbian Maternal and Child Health Hospital, Yanji, China
| | - Zhenxiang Yu
- Department of Neurosurgery, the First Hospital of Jilin University, Changchun, China
| | - Huiyi Jiang
- Department of Neurosurgery, the First Hospital of Jilin University, Changchun, China
| | - Bingjin Li
- Jilin Provincial Key Laboratory on Molecular and Chemical Genetic, The Second Hospital of Jilin University, Changchun, China
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232
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A characterization of Gaucher iPS-derived astrocytes: Potential implications for Parkinson's disease. Neurobiol Dis 2019; 134:104647. [PMID: 31669751 DOI: 10.1016/j.nbd.2019.104647] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Revised: 10/14/2019] [Accepted: 10/23/2019] [Indexed: 12/20/2022] Open
Abstract
While astrocytes, the most abundant cells found in the brain, have many diverse functions, their role in the lysosomal storage disorder Gaucher disease (GD) has not been explored. GD, resulting from the inherited deficiency of the enzyme glucocerebrosidase and subsequent accumulation of glucosylceramide and its acylated derivative glucosylsphingosine, has both non-neuronopathic (GD1) and neuronopathic forms (GD2 and 3). Furthermore, mutations in GBA1, the gene mutated in GD, are an important risk factor for Parkinson's disease (PD). To elucidate the role of astrocytes in the disease pathogenesis, we generated iAstrocytes from induced pluripotent stem cells made from fibroblasts taken from controls and patients with GD1, with and without PD. We also made iAstrocytes from an infant with GD2, the most severe and progressive form, manifesting in infancy. Gaucher iAstrocytes appropriately showed deficient glucocerebrosidase activity and levels and substrate accumulation. These cells exhibited varying degrees of astrogliosis, Glial Fibrillary Acidic Protein (GFAP) up-regulation and cellular proliferation, depending on the level of residual glucocerebrosidase activity. Glutamte uptake assays demonstrated that the cells were functionally active, although the glutamine transporter EEAT2 was upregulated and EEAT1 downregulated in the GD2 samples. GD2 iAstrocytes were morphologically different, with severe cytoskeletal hypertrophy, overlapping of astrocyte processes, pronounced up-regulation of GFAP and S100β, and significant astrocyte proliferation, recapitulating the neuropathology observed in patients with GD2. Although astrocytes do not express α-synuclein, when the iAstrocytes were co-cultured with dopaminergic neurons generated from the same iPSC lines, excessive α-synuclein released from neurons was endocytosed by astrocytes, translocating into lysosomes. Levels of aggregated α-synuclein increased significantly when cells were treated with monomeric or fibrillar α-synuclein. GD1-PD and GD2 iAstrocytes also exhibited impaired Cathepsin D activity, leading to further α-synuclein accumulation. Cytokine and chemokine profiling of the iAstrocytes demonstrated an inflammatory response. Thus, in patients with GBA1-associated parkinsonism, astrocytes appear to play a role in α-synuclein accumulation and processing, contributing to neuroinflammation.
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233
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Neuroinflammation in Post-Traumatic Epilepsy: Pathophysiology and Tractable Therapeutic Targets. Brain Sci 2019; 9:brainsci9110318. [PMID: 31717556 PMCID: PMC6895909 DOI: 10.3390/brainsci9110318] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Revised: 10/31/2019] [Accepted: 11/08/2019] [Indexed: 02/06/2023] Open
Abstract
Epilepsy is a common chronic consequence of traumatic brain injury (TBI), contributing to increased morbidity and mortality for survivors. As post-traumatic epilepsy (PTE) is drug-resistant in at least one-third of patients, there is a clear need for novel therapeutic strategies to prevent epilepsy from developing after TBI, or to mitigate its severity. It has long been recognized that seizure activity is associated with a local immune response, characterized by the activation of microglia and astrocytes and the release of a plethora of pro-inflammatory cytokines and chemokines. More recently, increasing evidence also supports a causal role for neuroinflammation in seizure induction and propagation, acting both directly and indirectly on neurons to promote regional hyperexcitability. In this narrative review, we focus on key aspects of the neuroinflammatory response that have been implicated in epilepsy, with a particular focus on PTE. The contributions of glial cells, blood-derived leukocytes, and the blood–brain barrier will be explored, as well as pro- and anti-inflammatory mediators. While the neuroinflammatory response to TBI appears to be largely pro-epileptogenic, further research is needed to clearly demonstrate causal relationships. This research has the potential to unveil new drug targets for PTE, and identify immune-based biomarkers for improved epilepsy prediction.
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234
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Beiersdorfer A, Wolburg H, Grawe J, Scheller A, Kirchhoff F, Lohr C. Sublamina-specific organization of the blood brain barrier in the mouse olfactory nerve layer. Glia 2019; 68:631-645. [PMID: 31696993 DOI: 10.1002/glia.23744] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Revised: 10/17/2019] [Accepted: 10/18/2019] [Indexed: 01/19/2023]
Abstract
Astrocytes constitute the main glial component of the mammalian blood brain barrier (BBB). However, in the olfactory bulb (OB), the olfactory nerve layer (ONL) is almost devoid of astrocytes, raising the question which glial cells are part of the BBB. We used mice expressing EGFP in astrocytes and tdTomato in olfactory ensheathing cells (OECs), a specialized type of glial cells in the ONL, to unequivocally identify both glial cell types and investigate their contribution to the BBB in the olfactory bulb. OECs were located exclusively in the ONL, while somata of astrocytes were located in deeper layers and extended processes in the inner sublamina of the ONL. These processes surrounded blood vessels and contained aquaporin-4, an astrocytic protein enriched at the BBB. In the outer sublamina of the ONL, in contrast, blood vessels were surrounded by aquaporin-4-negative processes of OECs. Transcardial perfusion of blood vessels with lanthanum and subsequent visualization by electron microscopy showed that blood vessels enwrapped by OECs possessed intact tight junctions. In acute olfactory bulb preparations, injection of fluorescent glucose 6-NBDG into blood vessels resulted in labeling of OECs, indicating glucose transport from the perivascular space into OECs. In addition, Ca2+ transients in OECs in the outer sublamina evoked vasoconstriction, whereas Ca2+ signaling in OECs of the inner sublamina had no effect on adjacent blood vessels. Our results demonstrate that the BBB in the inner sublamina of the ONL contains astrocytes, while in the outer ONL OECs are part of the BBB.
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Affiliation(s)
| | - Hartwig Wolburg
- Institute of Pathology and Neuropathology, University of Tübingen, Tübingen, Germany
| | - Janine Grawe
- Division of Neurophysiology, University of Hamburg, Hamburg, Germany
| | - Anja Scheller
- Molecular Physiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), University of Saarland, Homburg, Germany
| | - Frank Kirchhoff
- Molecular Physiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), University of Saarland, Homburg, Germany
| | - Christian Lohr
- Division of Neurophysiology, University of Hamburg, Hamburg, Germany
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235
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Katayama K, Matsuda N, Kakuta K, Naraoka M, Takemura A, Hasegawa S, Akasaka K, Shimamura N, Itoh K, Asano K, Konno H, Ohkuma H. The Effect of Goreisan on the Prevention of Chronic Subdural Hematoma Recurrence: Multi-Center Randomized Controlled Study. J Neurotrauma 2019; 35:1537-1542. [PMID: 29444611 DOI: 10.1089/neu.2017.5407] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The relatively high rate of post-operative recurrence in the treatment of chronic subdural hematoma (CSDH) is a significant problem. Goreisan is an herbal medicine that exhibits a hydragogue effect by inhibiting the expression of aquaporins, and its efficacy in preventing post-operative CSDH recurrence has been suggested by several case trials. This multi-center prospective randomized controlled trial was performed to investigate the preventative effect of goreisan on post-operative CSDH recurrence. Patients with symptomatic CSDH over 60 years old undergoing burr hole surgery were enrolled in this study. The patients were randomly allocated to the control group or the goreisan group, in which oral administration of goreisan (7.5 g daily) was continued for 12 weeks. The primary end-point was the post-operative recurrence rate at 12 weeks and the secondary end-point was hematoma volume reduction rates on computed tomography scan at 12 weeks. The analyses were performed not only on patients of all ages older than 60 years, but also on patients divided into those over or under 75 years old. One hundred and eighty patients were followed and analyzed (the control group, n = 88; the goreisan group, n = 92). The recurrence rates considering patients of all ages and patients under 75 years old were relatively low in the goreisan group but without a significant difference. The hematoma volume reduction rates showed no significant difference. Based on the results of the present study, a larger-scale study including more cases is necessary in future to confirm the efficacy of goreisan.
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Affiliation(s)
- Kosuke Katayama
- 1 Department of Neurosurgery, Hirosaki University Graduate School of Medicine , Aomori, Japan
| | - Naoya Matsuda
- 1 Department of Neurosurgery, Hirosaki University Graduate School of Medicine , Aomori, Japan
| | - Kiyohide Kakuta
- 1 Department of Neurosurgery, Hirosaki University Graduate School of Medicine , Aomori, Japan
| | - Masato Naraoka
- 1 Department of Neurosurgery, Hirosaki University Graduate School of Medicine , Aomori, Japan
| | | | - Seiko Hasegawa
- 3 Department of Neurosurgery, Kuroishi Hopital , Aomori, Japan
| | - Kenichi Akasaka
- 4 Department of Neurosurgery, Towada Central Hopital , Aomori, Japan
| | - Norihito Shimamura
- 1 Department of Neurosurgery, Hirosaki University Graduate School of Medicine , Aomori, Japan
| | - Katsuhiro Itoh
- 1 Department of Neurosurgery, Hirosaki University Graduate School of Medicine , Aomori, Japan
| | - Kenichiro Asano
- 1 Department of Neurosurgery, Hirosaki University Graduate School of Medicine , Aomori, Japan
| | - Hiromu Konno
- 5 Department of Neurosurgery, Hachinohe Japanese Red Cross Hospital , Aomori, Japan
| | - Hiroki Ohkuma
- 1 Department of Neurosurgery, Hirosaki University Graduate School of Medicine , Aomori, Japan
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Halstead MR, Geocadin RG. The Medical Management of Cerebral Edema: Past, Present, and Future Therapies. Neurotherapeutics 2019; 16:1133-1148. [PMID: 31512062 PMCID: PMC6985348 DOI: 10.1007/s13311-019-00779-4] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Cerebral edema is commonly associated with cerebral pathology, and the clinical manifestation is largely related to the underlying lesioned tissue. Brain edema usually amplifies the dysfunction of the lesioned tissue and the burden of cerebral edema correlates with increased morbidity and mortality across diseases. Our modern-day approach to the medical management of cerebral edema has largely revolved around, an increasingly artificial distinction between cytotoxic and vasogenic cerebral edema. These nontargeted interventions such as hyperosmolar agents and sedation have been the mainstay in clinical practice and offer noneloquent solutions to a dire problem. Our current understanding of the underlying molecular mechanisms driving cerebral edema is becoming much more advanced, with differences being identified across diseases and populations. As our understanding of the underlying molecular mechanisms in neuronal injury continues to expand, so too is the list of targeted therapies in the pipeline. Here we present a brief review of the molecular mechanisms driving cerebral edema and a current overview of our understanding of the molecular targets being investigated.
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Affiliation(s)
- Michael R Halstead
- Neurosciences Critical Care Division, Departments of Neurology, Anesthesiology-Critical Care Medicine and Neurosurgery, Johns Hopkins University School of Medicine, Baltimore, Maryland, 21287, USA.
| | - Romergryko G Geocadin
- Neurosciences Critical Care Division, Departments of Neurology, Anesthesiology-Critical Care Medicine and Neurosurgery, Johns Hopkins University School of Medicine, Baltimore, Maryland, 21287, USA
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237
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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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238
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Wang Y, Wang Y, Du X, Yan S, Zhang P, Chen HY, Huang S. Electrode-free nanopore sensing by DiffusiOptoPhysiology. SCIENCE ADVANCES 2019; 5:eaar3309. [PMID: 31523706 PMCID: PMC6731070 DOI: 10.1126/sciadv.aar3309] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Accepted: 08/02/2019] [Indexed: 05/24/2023]
Abstract
A wide variety of single molecules can be identified by nanopore sensing. However, all reported nanopore sensing applications result from the same measurement configuration adapted from electrophysiology. Although urgently needed in commercial nanopore sequencing, parallel electrophysiology recording is limited in its cost and its throughput due to the introduced complexities from electronic integration. We present the first electrode-free nanopore sensing method defined as DiffusiOptoPhysiology (DOP), in which single-molecule events are monitored optically without any electrical connections. Single-molecule sensing of small molecules, macromolecules, and biomacromolecules was subsequently demonstrated. As a further extension, a fingertip-sized, multiplexed chip with single-molecule sensing capabilities has been introduced, which suggests a new concept of clinical diagnosis using disposable nanopore sensors. DOP, which is universally compatible with all types of channels and a variety of fluorescence imaging platforms, may benefit diverse areas such as nanopore sequencing, drug screening, and channel protein investigations.
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Affiliation(s)
- Yuqin Wang
- State Key Laboratory of Analytical Chemistry for Life Sciences, Nanjing University, 210023 Nanjing, China
- School of Chemistry and Chemical Engineering, Nanjing University, 210023 Nanjing, China
| | - Yu Wang
- State Key Laboratory of Analytical Chemistry for Life Sciences, Nanjing University, 210023 Nanjing, China
- School of Chemistry and Chemical Engineering, Nanjing University, 210023 Nanjing, China
| | - Xiaoyu Du
- State Key Laboratory of Analytical Chemistry for Life Sciences, Nanjing University, 210023 Nanjing, China
- School of Chemistry and Chemical Engineering, Nanjing University, 210023 Nanjing, China
| | - Shuanghong Yan
- State Key Laboratory of Analytical Chemistry for Life Sciences, Nanjing University, 210023 Nanjing, China
- School of Chemistry and Chemical Engineering, Nanjing University, 210023 Nanjing, China
| | - Panke Zhang
- State Key Laboratory of Analytical Chemistry for Life Sciences, Nanjing University, 210023 Nanjing, China
- School of Chemistry and Chemical Engineering, Nanjing University, 210023 Nanjing, China
- Collaborative Innovation Center of Chemistry for Life Sciences, Nanjing University, 210023 Nanjing, China
| | - Hong-Yuan Chen
- State Key Laboratory of Analytical Chemistry for Life Sciences, Nanjing University, 210023 Nanjing, China
- School of Chemistry and Chemical Engineering, Nanjing University, 210023 Nanjing, China
- Collaborative Innovation Center of Chemistry for Life Sciences, Nanjing University, 210023 Nanjing, China
| | - Shuo Huang
- State Key Laboratory of Analytical Chemistry for Life Sciences, Nanjing University, 210023 Nanjing, China
- School of Chemistry and Chemical Engineering, Nanjing University, 210023 Nanjing, China
- Collaborative Innovation Center of Chemistry for Life Sciences, Nanjing University, 210023 Nanjing, China
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239
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Chang VTW, Chang HM. Review: Recent advances in the understanding of the pathophysiology of neuromyelitis optica spectrum disorder. Neuropathol Appl Neurobiol 2019; 46:199-218. [PMID: 31353503 DOI: 10.1111/nan.12574] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Revised: 07/17/2019] [Accepted: 07/24/2019] [Indexed: 12/11/2022]
Abstract
Neuromyelitis optica is an autoimmune inflammatory disorder of the central nervous system that preferentially targets the spinal cord and optic nerve. Following the discovery of circulating antibodies against the astrocytic aquaporin 4 (AQP4) water channel protein, recent studies have expanded our knowledge of the unique complexities of the pathogenesis of neuromyelitis optica and its relationship with the immune response. This review describes and summarizes the recent advances in our understanding of the molecular mechanisms underlying neuromyelitis optica disease pathology and examines their potential as therapeutic targets. Additionally, we update the most recent research by proposing major unanswered questions regarding how peripheral AQP4 antibodies are produced and their entry into the central nervous system, the causes of AQP4-IgG-seronegative disease, why peripheral AQP4-expressing organs are spared from damage, and the impact of this disease on pregnancy.
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Affiliation(s)
- V T W Chang
- St George's, University of London, London, UK
| | - H-M Chang
- Department of Obstetrics and Gynaecology, University of British Columbia and BC Children's Hospital Research Institute, Vancouver, BC, Canada
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240
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Abstract
Two third of our body is composed of water molecules. Regulation of water and electrolytes is indeed the most important homeostatic functions. Many diseases, such as heart failure, are associated with disturbance in fluid homeostasis. Surprisingly, water dynamics inside the brain is still largely unknown. In 2012, a new concept referred as "glymphatic system" was proposed by Nedergaard's group, where aquaporin4 (AQP4) may play an important role as well as sleep. AQP4 is mainly expressed in the central nervous system, especially in the foot processes of astrocytes; surrounding the capillary, beneath pia matter and lining the ventricles. The unique distribution of AQP4 suggest that AQP4 might play a role in brain water homeostasis. The concept of "glymphatic system" is still controversial, and needs to be clarified with new experimental data. This approach will lead to the better understanding of roles of astrocytes in neurodegenerative diseases and pharmacokinetics inside the brain, and eventually will facilitate the development of new drugs for sleep or mental disorders. It has been accumulating evidence that sleep disturbance is related to several kinds of chronic diseases such as hypertension and diabetes. In addition, the number of patients with dementia are significantly increasing. It is therefore critical to understand the physiological and pathological mechanisms of brain lymphatic system from the medical and social point of views. Here I will discuss about the roles of AQP4 in neurodegenerative diseases and introduce new knowledge regarding to "glymphatic system".
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Affiliation(s)
- Masato Yasui
- Department of Pharmacology, Keio University School of Medicine
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241
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Bruscolini A, La Cava M, Mallone F, Marcelli M, Ralli M, Sagnelli P, Greco A, Lambiase A. Controversies in the management of neuromyelitis optica spectrum disorder. Expert Rev Neurother 2019; 19:1127-1133. [DOI: 10.1080/14737175.2019.1648210] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Alice Bruscolini
- Department of Sense Organs, University Sapienza of Rome, Rome, Italy
| | - Maurizio La Cava
- Department of Sense Organs, University Sapienza of Rome, Rome, Italy
| | - Fabiana Mallone
- Department of Sense Organs, University Sapienza of Rome, Rome, Italy
| | - Michela Marcelli
- Department of Sense Organs, University Sapienza of Rome, Rome, Italy
| | - Massimo Ralli
- Department of Sense Organs, University Sapienza of Rome, Rome, Italy
| | - Paolo Sagnelli
- Department of Sense Organs, University Sapienza of Rome, Rome, Italy
| | - Antonio Greco
- Department of Sense Organs, University Sapienza of Rome, Rome, Italy
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242
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Thebault S, R Tessier D, Lee H, Bowman M, Bar-Or A, Arnold DL, L Atkins H, Tabard-Cossa V, Freedman MS. High serum neurofilament light chain normalizes after hematopoietic stem cell transplantation for MS. NEUROLOGY-NEUROIMMUNOLOGY & NEUROINFLAMMATION 2019; 6:e598. [PMID: 31516913 PMCID: PMC6715458 DOI: 10.1212/nxi.0000000000000598] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Accepted: 04/29/2019] [Indexed: 12/02/2022]
Abstract
Objective To evaluate neurofilament light chain (NfL) levels in serum and CSF of patients with aggressive MS pre- and post-treatment with immunoablation followed by autologous hematopoietic stem cell transplantation (IAHSCT) and examine associations with clinical and MRI outcomes. Methods Paired serum and CSF in addition to MRI and clinical measures were collected on 23 patients with MS at baseline and 1 and 3 years post-IAHSCT. An additional 33 sera and CSF pairs were taken from noninflammatory neurologic controls. NfL levels were quantitated using the Simoa platform (Quanterix). Results Baseline MS NfL levels were significantly elevated relative to controls in serum (p = 0.001) and CSF (p = 0.001). Following IAHSCT, high pretreatment NfL levels significantly reduced in serum (p = 0.0023) and CSF (p = 0.0068) and were not significantly different from controls. Serum and CSF NfL levels highly correlated (r = 0.81, p < 0.0001). Baseline NfL levels were associated with worse pretreatment disease measures (Expanded Disability Status Scale [EDSS], relapses, MRI lesions, and MR spectroscopy (MRS) N-acetylaspartate/creatine). Elevated baseline NfL levels were associated with persistently worse indices of disease burden post-IAHSCT (sustained EDSS progression, cognition, quality of life, T1 and T2 lesion volumes, MRS, and brain atrophy). Conclusion These data substantiate that serum and CSF NfL levels reflect disease severity and treatment response in patients with MS and may therefore be a useful biomarker. Baseline serum levels associated with markers of pretreatment disease severity and post-treatment outcomes. Classification of evidence This study provides Class II evidence that for patients with aggressive MS, serum NfL levels are associated with disease severity.
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Affiliation(s)
- Simon Thebault
- The University of Ottawa and Ottawa Hospital Research Institute (S.T., M.B., H.L.A., M.S.F.); Department of Physics (D.R.T., V.T.-C.), University of Ottawa; Montreal Neurological Institute (H.L., D.L.A.); and Perelman School of Medicine and University of Pennsylvania (A.B.-O.)
| | - Daniel R Tessier
- The University of Ottawa and Ottawa Hospital Research Institute (S.T., M.B., H.L.A., M.S.F.); Department of Physics (D.R.T., V.T.-C.), University of Ottawa; Montreal Neurological Institute (H.L., D.L.A.); and Perelman School of Medicine and University of Pennsylvania (A.B.-O.)
| | - Hyunwoo Lee
- The University of Ottawa and Ottawa Hospital Research Institute (S.T., M.B., H.L.A., M.S.F.); Department of Physics (D.R.T., V.T.-C.), University of Ottawa; Montreal Neurological Institute (H.L., D.L.A.); and Perelman School of Medicine and University of Pennsylvania (A.B.-O.)
| | - Marjorie Bowman
- The University of Ottawa and Ottawa Hospital Research Institute (S.T., M.B., H.L.A., M.S.F.); Department of Physics (D.R.T., V.T.-C.), University of Ottawa; Montreal Neurological Institute (H.L., D.L.A.); and Perelman School of Medicine and University of Pennsylvania (A.B.-O.)
| | - Amit Bar-Or
- The University of Ottawa and Ottawa Hospital Research Institute (S.T., M.B., H.L.A., M.S.F.); Department of Physics (D.R.T., V.T.-C.), University of Ottawa; Montreal Neurological Institute (H.L., D.L.A.); and Perelman School of Medicine and University of Pennsylvania (A.B.-O.)
| | - Douglas L Arnold
- The University of Ottawa and Ottawa Hospital Research Institute (S.T., M.B., H.L.A., M.S.F.); Department of Physics (D.R.T., V.T.-C.), University of Ottawa; Montreal Neurological Institute (H.L., D.L.A.); and Perelman School of Medicine and University of Pennsylvania (A.B.-O.)
| | - Harold L Atkins
- The University of Ottawa and Ottawa Hospital Research Institute (S.T., M.B., H.L.A., M.S.F.); Department of Physics (D.R.T., V.T.-C.), University of Ottawa; Montreal Neurological Institute (H.L., D.L.A.); and Perelman School of Medicine and University of Pennsylvania (A.B.-O.)
| | - Vincent Tabard-Cossa
- The University of Ottawa and Ottawa Hospital Research Institute (S.T., M.B., H.L.A., M.S.F.); Department of Physics (D.R.T., V.T.-C.), University of Ottawa; Montreal Neurological Institute (H.L., D.L.A.); and Perelman School of Medicine and University of Pennsylvania (A.B.-O.)
| | - Mark S Freedman
- The University of Ottawa and Ottawa Hospital Research Institute (S.T., M.B., H.L.A., M.S.F.); Department of Physics (D.R.T., V.T.-C.), University of Ottawa; Montreal Neurological Institute (H.L., D.L.A.); and Perelman School of Medicine and University of Pennsylvania (A.B.-O.)
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243
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Retinal and optic nerve degeneration in liver X receptor β knockout mice. Proc Natl Acad Sci U S A 2019; 116:16507-16512. [PMID: 31371497 DOI: 10.1073/pnas.1904719116] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The retina is an extension of the brain. Like the brain, neurodegeneration of the retina occurs with age and is the cause of several retinal diseases including optic neuritis, macular degeneration, and glaucoma. Liver X receptors (LXRs) are expressed in the brain where they play a key role in maintenance of cerebrospinal fluid and the health of dopaminergic neurons. Herein, we report that LXRs are expressed in the retina and optic nerve and that loss of LXRβ, but not LXRα, leads to loss of ganglion cells in the retina. In the retina of LXRβ-/- mice, there is an increase in amyloid A4 and deposition of beta-amyloid (Aβ) aggregates but no change in the level of apoptosis or autophagy in the ganglion cells and no activation of microglia or astrocytes. However, in the optic nerve there is a loss of aquaporin 4 (AQP4) in astrocytes and an increase in activation of microglia. Since loss of AQP4 and microglial activation in the optic nerve precedes the loss of ganglion cells, and accumulation of Aβ in the retina, the cause of the neuronal loss appears to be optic nerve degeneration. In patients with optic neuritis there are frequently AQP4 autoantibodies which block the function of AQP4. LXRβ-/- mouse is another model of optic neuritis in which AQP4 antibodies are not detectable, but AQP4 function is lost because of reduction in its expression.
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244
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Demirgan S, Akyol O, Temel Z, Şengelen A, Pekmez M, Demirgan R, Sevdi MS, Erkalp K, Selcan A. Isoflurane exposure in infant rats acutely increases aquaporin 4 and does not cause neurocognitive impairment. Bosn J Basic Med Sci 2019; 19. [PMID: 30821219 PMCID: PMC6716098 DOI: 10.17305/bjbms.2018.4116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Isoflurane is commonly used in pediatric population, but its mechanism of action in cognition is unclear. Aquaporin 4 (AQP4) regulates water content in blood, brain, and cerebrospinal fluid. Various studies have provided evidence for the role of AQP4 in synaptic plasticity and neurocognition. In this study, we aimed to determine whether a prolonged exposure to isoflurane in infant rats is associated with cognition and what effect this exposure has on AQP4 expression. Ten-day-old [postnatal day (P) 10] Wistar albino rats were randomly allocated to isoflurane group (n = 32; 1.5% isoflurane in 50% oxygen for 6 hours) or control group (n = 32; only 50% oxygen for 6 hours). Acute (P11) and long-term (P33) effects of 6-hour anesthetic isoflurane exposure on AQP4 expression were analyzed in whole brains of P11 and P33 rats by RT-qPCR and Western blot. Spatial learning and memory were assessed on P28 to P33 days by Morris Water Maze (MWM) test. The analysis revealed that isoflurane increased acutely both mRNA (~4.5 fold) and protein (~90%) levels of AQP4 in P11 rats compared with control group. The increasing levels of AQP4 in P11 were not observed in P33 rats. Also, no statistically significant change between isoflurane and control groups was observed in the latency to find the platform during MWM training and probe trial. Our results indicate that a single exposure to isoflurane anesthesia does not influence cognition in infant rats. In this case, acutely increased AQP4 after isoflurane anesthesia may have a protective role in neurocognition.
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Affiliation(s)
- Serdar Demirgan
- T.C. Health Ministry, Health Sciences University, Bagcilar Training and Research Hospital, Anesthesiology and Reanimation Clinic, Istanbul, Turkey,Department of Molecular Biology and Genetics, Institute of Graduate Studies in Sciences, Istanbul University, Istanbul, Turkey,Corresponding author: Serdar Demirgan, T.C. Health Ministry, Health Sciences University, Bagcilar Training and Research Hospital, Anesthesiology and Reanimation Clinic, Dr. Sadık Ahmet Road, 34100 Bagcilar/Istanbul, Turkey. Phone: +90 5058099616; Fax: +90 212 440 42 42. E-mail: .
| | - Onat Akyol
- T.C. Health Ministry, Health Sciences University, Bagcilar Training and Research Hospital, Anesthesiology and Reanimation Clinic, Istanbul, Turkey
| | - Zeynep Temel
- Department of Neuroscience Institute of Health Sciences, Istanbul Medipol University, Istanbul, Turkey
| | - Aslıhan Şengelen
- Department of Molecular Biology and Genetics, Institute of Graduate Studies in Sciences, Istanbul University, Istanbul, Turkey
| | - Murat Pekmez
- Department of Molecular Biology and Genetics, Faculty of Science, Istanbul University, Istanbul, Turkey
| | - Recep Demirgan
- Department of Molecular Biology and Genetics, Institute of Graduate Studies in Sciences, Istanbul University, Istanbul, Turkey
| | - Mehmet Salih Sevdi
- T.C. Health Ministry, Health Sciences University, Bagcilar Training and Research Hospital, Anesthesiology and Reanimation Clinic, Istanbul, Turkey
| | - Kerem Erkalp
- T.C. Health Ministry, Health Sciences University, Bagcilar Training and Research Hospital, Anesthesiology and Reanimation Clinic, Istanbul, Turkey
| | - Ayşin Selcan
- T.C. Health Ministry, Health Sciences University, Bagcilar Training and Research Hospital, Anesthesiology and Reanimation Clinic, Istanbul, Turkey
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245
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Zhang R, Liu Y, Chen Y, Li Q, Marshall C, Wu T, Hu G, Xiao M. Aquaporin 4 deletion exacerbates brain impairments in a mouse model of chronic sleep disruption. CNS Neurosci Ther 2019; 26:228-239. [PMID: 31364823 PMCID: PMC6978250 DOI: 10.1111/cns.13194] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Revised: 06/20/2019] [Accepted: 06/26/2019] [Indexed: 12/24/2022] Open
Abstract
AIMS As a normal physiological process, sleep has recently been shown to facilitate clearance of macromolecular metabolic wastes from the brain via the glymphatic system. The aim of the present study was to investigate pathophysiological roles of astroglial aquaporin 4 (AQP4), a functional regulator of glymphatic clearance, in a mouse model of chronic sleep disruption (SD). METHODS Adult AQP4 null mice and wild-type (WT) mice were given 7 days of SD using the improved rotating rod method, and then received behavioral, neuropathological, and neurochemical analyses. RESULTS Aquaporin 4 deletion resulted in an impairment of glymphatic transport and accumulation of β-amyloid and Tau proteins in the brain following SD. AQP4 null SD mice exhibited severe activation of microglia, neuroinflammation, and synaptic protein loss in the hippocampus, as well as decreased working memory, compared with WT-SD mice. CONCLUSION These results demonstrate that AQP4-mediated glymphatic clearance ameliorates brain impairments caused by abnormal accumulation of metabolic wastes following chronic SD, thus serving as a potential target for sleep-related disorders.
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Affiliation(s)
- Rui Zhang
- Department of Neurology, the First Affiliated Hospital of Nanjing Medical University, Nanjing, China.,Jiangsu Province, Key Laboratory of Neurodegeneration, Nanjing Medical University, Nanjing, China
| | - Yun Liu
- Department of Neurology, the First Affiliated Hospital of Nanjing Medical University, Nanjing, China.,Jiangsu Province, Key Laboratory of Neurodegeneration, Nanjing Medical University, Nanjing, China
| | - Yan Chen
- Jiangsu Province, Key Laboratory of Neurodegeneration, Nanjing Medical University, Nanjing, China.,Brain Institute, the Affiliated Nanjing Brain Hospital of Nanjing Medical University, Nanjing, China
| | - Qian Li
- Jiangsu Province, Key Laboratory of Neurodegeneration, Nanjing Medical University, Nanjing, China.,Brain Institute, the Affiliated Nanjing Brain Hospital of Nanjing Medical University, Nanjing, China
| | - Charles Marshall
- Department of Rehabilitation Sciences, University of Kentucky Center of Excellence in Rural Health, Hazard, KY, USA
| | - Ting Wu
- Department of Neurology, the First Affiliated Hospital of Nanjing Medical University, Nanjing, China.,Jiangsu Province, Key Laboratory of Neurodegeneration, Nanjing Medical University, Nanjing, China
| | - Gang Hu
- Jiangsu Province, Key Laboratory of Neurodegeneration, Nanjing Medical University, Nanjing, China
| | - Ming Xiao
- Jiangsu Province, Key Laboratory of Neurodegeneration, Nanjing Medical University, Nanjing, China.,Brain Institute, the Affiliated Nanjing Brain Hospital of Nanjing Medical University, Nanjing, China
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Eilert-Olsen M, Hjukse JB, Thoren AE, Tang W, Enger R, Jensen V, Pettersen KH, Nagelhus EA. Astroglial endfeet exhibit distinct Ca 2+ signals during hypoosmotic conditions. Glia 2019; 67:2399-2409. [PMID: 31350866 DOI: 10.1002/glia.23692] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2019] [Revised: 07/12/2019] [Accepted: 07/16/2019] [Indexed: 11/09/2022]
Abstract
Astrocytic endfeet cover the brain surface and form a sheath around the cerebral vasculature. An emerging concept is that endfeet control blood-brain water transport and drainage of interstitial fluid and waste along paravascular pathways. Little is known about the signaling mechanisms that regulate endfoot volume and hence the width of these drainage pathways. Here, we used the genetically encoded fluorescent Ca2+ indicator GCaMP6f to study Ca2+ signaling within astrocytic somata, processes, and endfeet in response to an osmotic challenge known to induce cell swelling. Acute cortical slices were subjected to artificial cerebrospinal fluid with 20% reduction in osmolarity while GCaMP6f fluorescence was imaged with two-photon microscopy. Ca2+ signals induced by hypoosmotic conditions were observed in all astrocytic compartments except the soma. The Ca2+ response was most prominent in subpial and perivascular endfeet and included spikes with single peaks, plateau-type elevations, and rapid oscillations, the latter restricted to subpial endfeet. Genetic removal of the type 2 inositol 1,4,5-triphosphate receptor (IP3R2) severely suppressed the Ca2+ responses in endfeet but failed to affect brain water accumulation in vivo after water intoxication. Furthermore, the increase in endfoot Ca2+ spike rate during hypoosmotic conditions was attenuated in mutant mice lacking the aquaporin-4 anchoring molecule dystrophin and after blockage of transient receptor potential vanilloid 4 channels. We conclude that the characteristics and underpinning of Ca2+ responses to hypoosmotic stress differ within the astrocytic territory and that IP3R2 is essential for the Ca2+ signals only in subpial and perivascular endfeet.
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Affiliation(s)
- Martine Eilert-Olsen
- Division of Physiology, Department of Molecular Medicine, GliaLab and Letten Centre, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Jarand B Hjukse
- Division of Physiology, Department of Molecular Medicine, GliaLab and Letten Centre, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Anna E Thoren
- Division of Physiology, Department of Molecular Medicine, GliaLab and Letten Centre, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Wannan Tang
- Division of Physiology, Department of Molecular Medicine, GliaLab and Letten Centre, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Rune Enger
- Division of Physiology, Department of Molecular Medicine, GliaLab and Letten Centre, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway.,Department of Neurology, Oslo University Hospital, Oslo, Norway
| | - Vidar Jensen
- Division of Physiology, Department of Molecular Medicine, GliaLab and Letten Centre, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Klas H Pettersen
- Division of Physiology, Department of Molecular Medicine, GliaLab and Letten Centre, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Erlend A Nagelhus
- Division of Physiology, Department of Molecular Medicine, GliaLab and Letten Centre, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway.,Department of Neurology, Oslo University Hospital, Oslo, Norway
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247
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Papanikolaou M, Lewis A, Butt AM. Glial and neuronal expression of the Inward Rectifying Potassium Channel Kir7.1 in the adult mouse brain. J Anat 2019; 235:984-996. [PMID: 31309576 PMCID: PMC6794205 DOI: 10.1111/joa.13048] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/29/2019] [Indexed: 01/01/2023] Open
Abstract
Inward Rectifying Potassium channels (Kir) are a large family of ion channels that play key roles in ion homeostasis and neuronal excitability. The most recently described Kir subtype is Kir7.1, which is known as a K+ transporting subtype. Earlier studies localised Kir7.1 to subpopulations of neurones in the brain. However, the pattern of Kir7.1 expression across the brain has not previously been examined. Here, we have determined neuronal and glial expression of Kir7.1 in the adult mouse brain, using immunohistochemistry and transgenic mouse lines expressing reporters specific for astrocytes [glial fibrillary acidic protein‐enhanced green fluorescent protein (GFAP‐EGFP], myelinating oligodendrocytes (PLP‐DsRed), oligodendrocyte progenitor cells (OPC, Pdgfra‐creERT2/Rosa26‐YFP double‐transgenic mice) and all oligodendrocyte lineage cells (SOX10‐EGFP). The results demonstrate significant neuronal Kir7.1 immunostaining in the cortex, hippocampus, cerebellum and pons, as well as the striatum and hypothalamus. In addition, astrocytes are shown to be immunopositive for Kir7.1 throughout grey and white matter, with dense immunostaining on cell somata, primary processes and perivascular end‐feet. Immunostaining for Kir7.1 was observed in oligodendrocytes, myelin and OPCs throughout the brain, although immunostaining was heterogeneous. Neuronal and glial expression of Kir7.1 is confirmed using neurone‐glial cortical cultures and optic nerve glial cultures. Notably, Kir7.1 have been shown to regulate the excitability of thalamic neurones and our results indicate this may be a widespread function of Kir7.1 in neurones throughout the brain. Moreover, based on the function of Kir7.1 in multiple transporting epithelia, Kir7.1 are likely to play an equivalent role in the primary glial function of K+ homeostasis. Our results indicate Kir7.1 are far more pervasive in the brain than previously recognised and have potential importance in regulating neuronal and glial function.
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Affiliation(s)
- Maria Papanikolaou
- Institute of Biomedical and Biomolecular Sciences, School of Pharmacy and Biomedical Science, University of Portsmouth, Portsmouth, UK
| | - Anthony Lewis
- Institute of Biomedical and Biomolecular Sciences, School of Pharmacy and Biomedical Science, University of Portsmouth, Portsmouth, UK
| | - Arthur M Butt
- Institute of Biomedical and Biomolecular Sciences, School of Pharmacy and Biomedical Science, University of Portsmouth, Portsmouth, UK
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248
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Duan T, Smith AJ, Verkman AS. Complement-independent bystander injury in AQP4-IgG seropositive neuromyelitis optica produced by antibody-dependent cellular cytotoxicity. Acta Neuropathol Commun 2019; 7:112. [PMID: 31296268 PMCID: PMC6621951 DOI: 10.1186/s40478-019-0766-7] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Accepted: 07/01/2019] [Indexed: 12/25/2022] Open
Abstract
Cellular injury in AQP4-IgG seropositive neuromyelitis spectrum disorder (herein called NMO) involves AQP4-IgG binding to astrocytes, resulting in astrocyte injury by complement-dependent cytotoxicity (CDC) and antibody-dependent cellular cytotoxicity (ADCC) mechanisms. The rapid disease progression, severe tissue damage, and abundant leukocyte infiltration seen in some NMO patients suggest a more direct mechanism for demyelination and neurologic deficit than secondary injury from astrocyte loss. Here, we report evidence for an ‘ADCC bystander mechanism’ in NMO involving injury to nearby cells by leukocytes following their activation by AQP4-bound AQP4-IgG on astrocytes. In model cocultures containing AQP4-expressing and null CHO cells, AQP4-IgG and complement killed bystander null cells to ~ 100 μm away from AQP4-expressing cells; AQP4-IgG and NK cells produced bystander killing to ~ 300 μm, with perforin deposition seen on injured null cells. Bystander cytotoxicity was also seen with neutrophil-mediated ADCC and in astrocyte-neuron cocultures. Mechanistic studies, including real-time imaging, suggested that leukocytes activated by an AQP4-dependent ADCC mechanism injure bystander cells by direct targeted exocytosis on neighboring cells and not by diffusion of soluble granule contents. In support of this conclusion, ADCC bystander injury was preferentially reduced by an RGDS peptide that inhibits integrin adhesion. Evidence for ADCC bystander injury to oligodendrocytes and neurons was also found in mice following intracerebral injection of AQP4-IgG and NK cells, which was inhibited by RGDS peptide. These results establish a novel cellular pathogenesis mechanism in AQP4-IgG seropositive NMO and provide evidence that inflammatory mechanisms can cause widespread tissue damage in NMO independently of the secondary effects from astrocyte loss.
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249
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Amiry-Moghaddam M. AQP4 and the Fate of Gliomas. Cancer Res 2019; 79:2810-2811. [PMID: 31160309 DOI: 10.1158/0008-5472.can-19-1185] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Revised: 04/12/2019] [Accepted: 04/16/2019] [Indexed: 11/16/2022]
Abstract
High-grade glioma is the most common primary brain cancer type and is characterized by invasive and fast growth. In a previous issue of Cancer Research, Simone and colleagues show that the two isoforms of the aquaporin-4 (AQP4) water channel may determine the fate of gliomas. Glioma cell lines expressing the M23-AQP4 isoform, which forms large aggregates of orthogonal arrays of particles, shrink and undergo apoptosis, whereas cell lines expressing the tetramer-forming M1-AQP4 isoform display higher activity of matrix metalloproteinases, making them more invasive. This study provides new insight on the role of AQP4 isoforms in the biology of gliomas.See related article by Simone and colleagues; Cancer Res 79(9):2182-94.
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250
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Kobylarek D, Iwanowski P, Lewandowska Z, Limphaibool N, Szafranek S, Labrzycka A, Kozubski W. Advances in the Potential Biomarkers of Epilepsy. Front Neurol 2019; 10:685. [PMID: 31312171 PMCID: PMC6614180 DOI: 10.3389/fneur.2019.00685] [Citation(s) in RCA: 75] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2019] [Accepted: 06/12/2019] [Indexed: 12/11/2022] Open
Abstract
Epilepsy is a group of chronic neurological disorders characterized by recurrent, spontaneous, and unpredictable seizures. It is one of the most common neurological disorders, affecting tens of millions of people worldwide. Comprehensive studies on epilepsy in recent decades have revealed the complexity of epileptogenesis, in which immunological processes, epigenetic modifications, and structural changes in neuronal tissues have been identified as playing a crucial role. This review discusses the recent advances in the biomarkers of epilepsy. We evaluate the possible molecular background underlying the clinical changes observed in recent studies, focusing on therapeutic investigations, and the evidence of their safety and efficacy in the human population. This article reviews the pathophysiology of epilepsy, including recent reports on the effects of oxidative stress and hypoxia, and focuses on specific biomarkers and their clinical implications, along with further perspectives in epilepsy research.
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Affiliation(s)
- Dominik Kobylarek
- Department of Neurology, Poznan University of Medical Sciences, Poznan, Poland
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