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Amro Z, Collins-Praino LE, Yool AJ. Protective roles of peroxiporins AQP0 and AQP11 in human astrocyte and neuronal cell lines in response to oxidative and inflammatory stressors. Biosci Rep 2024; 44:BSR20231725. [PMID: 38451099 DOI: 10.1042/bsr20231725] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Revised: 03/03/2024] [Accepted: 03/06/2024] [Indexed: 03/08/2024] Open
Abstract
In addition to aquaporin (AQP) classes AQP1, AQP4 and AQP9 known to be expressed in mammalian brain, our recent transcriptomic analyses identified AQP0 and AQP11 in human cortex and hippocampus at levels correlated with age and Alzheimer's disease (AD) status; however, protein localization remained unknown. Roles of AQP0 and AQP11 in transporting hydrogen peroxide (H2O2) in lens and kidney prompted our hypothesis that up-regulation in brain might similarly be protective. Established cell lines for astroglia (1321N1) and neurons (SHSY5Y, differentiated with retinoic acid) were used to monitor changes in transcript levels for human AQPs (AQP0 to AQP12) in response to inflammation (simulated with 10-100 ng/ml lipopolysaccharide [LPS], 24 h), and hypoxia (5 min N2, followed by 0 to 24 h normoxia). AQP transcripts up-regulated in both 1321N1 and SHSY5Y included AQP0, AQP1 and AQP11. Immunocytochemistry in 1321N1 cells confirmed protein expression for AQP0 and AQP11 in plasma membrane and endoplasmic reticulum; AQP11 increased 10-fold after LPS and AQP0 increased 0.3-fold. In SHSY5Y cells, AQP0 expression increased 0.2-fold after 24 h LPS; AQP11 showed no appreciable change. Proposed peroxiporin roles were tested using melondialdehyde (MDA) assays to quantify lipid peroxidation levels after brief H2O2. Boosting peroxiporin expression by LPS pretreatment lowered subsequent H2O2-induced MDA responses (∼50%) compared with controls; conversely small interfering RNA knockdown of AQP0 in 1321N1 increased lipid peroxidation (∼17%) after H2O2, with a similar trend for AQP11 siRNA. Interventions that increase native brain peroxiporin activity are promising as new approaches to mitigate damage caused by aging and neurodegeneration.
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Affiliation(s)
- Zein Amro
- School of Biomedicine, University of Adelaide, Adelaide, SA 5005, Australia
| | | | - Andrea J Yool
- School of Biomedicine, University of Adelaide, Adelaide, SA 5005, Australia
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Silverglate B, Gao X, Lee HP, Maliha P, Grossberg GT. The aquaporin-4 water channel and updates on its potential as a drug target for Alzheimer's disease. Expert Opin Ther Targets 2023; 27:523-530. [PMID: 37475487 DOI: 10.1080/14728222.2023.2240017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Accepted: 07/19/2023] [Indexed: 07/22/2023]
Abstract
INTRODUCTION Although there are several FDA-approved treatments for Alzheimer's disease (AD), only recently have disease-modifying therapies received approval for use in patients. In this narrative review, we examine the history of aquaporin-4 (AQP4) as a therapeutic target for NMOSD (neuromyelitis optica spectrum disorder) and as a potential therapeutic target for AD. AREAS COVERED We review the basic science and discovery of AQP4, a transmembrane water-channel essential to regulating water balance in the central nervous system (CNS). We also review the pathogenesis of NMOSD, an autoimmune disease characterized by the destruction of cells that express AQP4. Then, we review how AQP4 is likely involved in the pathogenesis of Alzheimer's disease (AD). Finally, we discuss future challenges with drug design that would modulate AQP4 to potentially slow AD development. The literature search for this article consisted of searching Google Scholar and PubMed for permutations of the keywords 'Alzheimer's disease,' 'aquaporin-4,' 'neuromyelitis optica,' and their abbreviations. EXPERT OPINION We place research into AQP4 into context with other recent developments in AD research. A major difficulty with drug development for Alzheimer's is the lack of strategies to cleanly target the early pathogenesis of the disease. Targeting AQP4 may provide such a strategy.
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Affiliation(s)
- Bret Silverglate
- Division of Geriatric Psychiatry, St. Louis University School of Medicine, St. Louis, Missouri, USA
| | - Xiaoyi Gao
- Division of Geriatric Psychiatry, St. Louis University School of Medicine, St. Louis, Missouri, USA
| | - Hannah P Lee
- Division of Geriatric Psychiatry, St. Louis University School of Medicine, St. Louis, Missouri, USA
| | - Peter Maliha
- Carolyn Wells-Peterson Geriatric Psychiatry Research Fellow, St. Louis University School of Medicine, St. Louis, Missouri, USA
| | - George T Grossberg
- Division of Geriatric Psychiatry, St. Louis University School of Medicine, St. Louis, Missouri, USA
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Amro Z, Ryan M, Collins-Praino LE, Yool AJ. Unexpected Classes of Aquaporin Channels Detected by Transcriptomic Analysis in Human Brain Are Associated with Both Patient Age and Alzheimer’s Disease Status. Biomedicines 2023; 11:biomedicines11030770. [PMID: 36979749 PMCID: PMC10045580 DOI: 10.3390/biomedicines11030770] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Revised: 02/21/2023] [Accepted: 02/28/2023] [Indexed: 03/06/2023] Open
Abstract
The altered expression of known brain Aquaporin (AQP) channels 1, 4 and 9 has been correlated with neuropathological AD progression, but possible roles of other AQP classes in neurological disease remain understudied. The levels of transcripts of all thirteen human AQP subtypes were compared in healthy and Alzheimer’s disease (AD) brains by statistical analyses of microarray RNAseq expression data from the Allen Brain Atlas database. Previously unreported, AQPs 0, 6 and 10, are present in human brains at the transcript level. Three AD-affected brain regions, hippocampus (HIP), parietal cortex (PCx) and temporal cortex (TCx), were assessed in three subgroups: young controls (n = 6, aged 24–57); aged controls (n = 26, aged 78–99); and an AD cohort (n = 12, aged 79–99). A significant positive correlation (p < 10−10) was seen for AQP transcript levels as a function of the subject’s age in years. Differential expressions correlated with brain region, age, and AD diagnosis, particularly between the HIP and cortical regions. Interestingly, three classes of AQPs (0, 6 and 8) upregulated in AD compared to young controls are permeable to H2O2. Of these, AQPs 0 and 8 were increased in TCx and AQP6 in HIP, suggesting a role of AQPs in AD-related oxidative stress. The outcomes here are the first to demonstrate that the expression profile of AQP channels in the human brain is more diverse than previously thought, and transcript levels are influenced by both age and AD status. Associations between reactive oxygen stress and neurodegenerative disease risk highlight AQPs 0, 6, 8 and 10 as potential therapeutic targets.
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Affiliation(s)
- Zein Amro
- School of Biomedicine, University of Adelaide, Adelaide, SA 5005, Australia
| | - Matthew Ryan
- School of Mathematical Sciences, University of Adelaide, Adelaide, SA 5005, Australia
| | | | - Andrea J. Yool
- School of Biomedicine, University of Adelaide, Adelaide, SA 5005, Australia
- Correspondence:
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Xiao M, Hou J, Xu M, Li S, Yang B. Aquaporins in Nervous System. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1398:99-124. [PMID: 36717489 DOI: 10.1007/978-981-19-7415-1_7] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Aquaporins (AQPs) mediate water flux between the four distinct water compartments in the central nervous system (CNS). In the present chapter, we mainly focus on the expression and function of the nine AQPs expressed in the CNS, which include five members of aquaporin subfamily: AQP1, AQP4, AQP5, AQP6, and AQP8; three members of aquaglyceroporin subfamily: AQP3, AQP7, and AQP9; and one member of superaquaporin subfamily: AQP11. In addition, AQP1, AQP2, and AQP4 expressed in the peripheral nervous system are also reviewed. AQP4, the predominant water channel in the CNS, is involved both in the astrocyte swelling of cytotoxic edema and the resolution of vasogenic edema and is of pivotal importance in the pathology of brain disorders such as neuromyelitis optica, brain tumors, and neurodegenerative disorders. Moreover, AQP4 has been demonstrated as a functional regulator of recently discovered glymphatic system that is a main contributor to clearance of toxic macromolecule from the brain. Other AQPs are also involved in a variety of important physiological and pathological process in the brain. It has been suggested that AQPs could represent an important target in treatment of brain disorders like cerebral edema. Future investigations are necessary to elucidate the pathological significance of AQPs in the CNS.
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Affiliation(s)
- Ming Xiao
- Jiangsu Province, Key Laboratory of Neurodegeneration, Department of Pharmacology, Nanjing Medical University, Nanjing, China
| | - Jiaoyu Hou
- Department of Geriatrics, The First Hospital of Jilin University, Changchun, Jilin, China
| | - Mengmeng Xu
- Basic Medical College, Guizhou University of Traditional Chinese Medicine, Guiyang, China
| | - Shao Li
- Department of Physiology, Dalian Medical University, Dalian, China
| | - Baoxue Yang
- School of Basic Medical Sciences, Peking University, Beijing, China.
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The Water Transport System in Astrocytes–Aquaporins. Cells 2022; 11:cells11162564. [PMID: 36010640 PMCID: PMC9406552 DOI: 10.3390/cells11162564] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2022] [Revised: 07/26/2022] [Accepted: 08/08/2022] [Indexed: 11/16/2022] Open
Abstract
Highlights (AQPs) are transmembrane proteins responsible for fast water movement across cell membranes, including those of astrocytes. The expression and subcellular localization of AQPs in astrocytes are highly dynamic under physiological and pathological conditions. Besides their primary function in water homeostasis, AQPs participate in many ancillary functions including glutamate clearance in tripartite synapses and cell migration.
Abstract Astrocytes have distinctive morphological and functional characteristics, and are found throughout the central nervous system. Astrocytes are now known to be far more than just housekeeping cells in the brain. Their functions include contributing to the formation of the blood–brain barrier, physically and metabolically supporting and communicating with neurons, regulating the formation and functions of synapses, and maintaining water homeostasis and the microenvironment in the brain. Aquaporins (AQPs) are transmembrane proteins responsible for fast water movement across cell membranes. Various subtypes of AQPs (AQP1, AQP3, AQP4, AQP5, AQP8 and AQP9) have been reported to be expressed in astrocytes, and the expressions and subcellular localizations of AQPs in astrocytes are highly correlated with both their physiological and pathophysiological functions. This review describes and summarizes the recent advances in our understanding of astrocytes and AQPs in regard to controlling water homeostasis in the brain. Findings regarding the features of different AQP subtypes, such as their expression, subcellular localization, physiological functions, and the pathophysiological roles of astrocytes are presented, with brain edema and glioma serving as two representative AQP-associated pathological conditions. The aim is to provide a better insight into the elaborate “water distribution” system in cells, exemplified by astrocytes, under normal and pathological conditions.
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Antequera D, Carrero L, Cunha Alves V, Ferrer I, Hernández-Gallego J, Municio C, Carro E. Differentially Aquaporin 5 Expression in Submandibular Glands and Cerebral Cortex in Alzheimer’s Disease. Biomedicines 2022; 10:biomedicines10071645. [PMID: 35884950 PMCID: PMC9312791 DOI: 10.3390/biomedicines10071645] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 06/29/2022] [Accepted: 07/06/2022] [Indexed: 12/02/2022] Open
Abstract
Impaired brain clearance mechanisms may result in the accumulation of aberrant proteins that define Alzheimer’s disease (AD). The water channel protein astrocytic aquaporin 4 (AQP4) is essential for brain amyloid-β clearance, but it is known to be abnormally expressed in AD brains. The expression of AQPs is differentially regulated during diverse brain injuries, but, whereas AQP4 expression and function have been studied in AD, less is known about AQP5. AQP5 functions include not only water transport but also cell migration mediated by cytoskeleton regulation. Moreover, AQP5 has been reported to be expressed in astrocytes, which are regulated after ischemic and traumatic injury. Additionally, AQP5 is particularly abundant in the salivary glands suggesting that it may be a crucial factor in gland dysfunction associated with AD. Herein, we aim to determine whether AQP5 expression in submandibular glands and the brain was altered in AD. First, we demonstrated impaired AQP5 expression in submandibular glands in APP/PS1 mice and AD patients. Subsequently, we observed that AQP5 expression was upregulated in APP/PS1 cerebral cortex and confirmed its expression both in astrocytes and neurons. Our findings propose AQP5 as a significant role player in AD pathology, in addition to AQP4, representing a potential target for the treatment of AD.
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Affiliation(s)
- Desiree Antequera
- Group of Neurodegenerative Diseases, Hospital Universitario 12 de Octubre Research Institute (imas12), 28041 Madrid, Spain; (D.A.); (L.C.); (V.C.A.); (J.H.-G.)
- Network Center for Biomedical Research in Neurodegenerative Diseases (CIBERNED), ISCIII, 28031 Madrid, Spain;
| | - Laura Carrero
- Group of Neurodegenerative Diseases, Hospital Universitario 12 de Octubre Research Institute (imas12), 28041 Madrid, Spain; (D.A.); (L.C.); (V.C.A.); (J.H.-G.)
- Network Center for Biomedical Research in Neurodegenerative Diseases (CIBERNED), ISCIII, 28031 Madrid, Spain;
| | - Victoria Cunha Alves
- Group of Neurodegenerative Diseases, Hospital Universitario 12 de Octubre Research Institute (imas12), 28041 Madrid, Spain; (D.A.); (L.C.); (V.C.A.); (J.H.-G.)
- Network Center for Biomedical Research in Neurodegenerative Diseases (CIBERNED), ISCIII, 28031 Madrid, Spain;
| | - Isidro Ferrer
- Network Center for Biomedical Research in Neurodegenerative Diseases (CIBERNED), ISCIII, 28031 Madrid, Spain;
- Bellvitge Biomedical Research Institute (IDIBELL), 08908 Hospitalet de Llobregat, Spain
- Department of Pathology and Experimental Therapeutics, University of Barcelona, 08907 Hospitalet de Llobregat, Spain
- Institute of Neurosciences, University of Barcelona, 08035 Barcelona, Spain
| | - Jesús Hernández-Gallego
- Group of Neurodegenerative Diseases, Hospital Universitario 12 de Octubre Research Institute (imas12), 28041 Madrid, Spain; (D.A.); (L.C.); (V.C.A.); (J.H.-G.)
- Network Center for Biomedical Research in Neurodegenerative Diseases (CIBERNED), ISCIII, 28031 Madrid, Spain;
- Department of Neurology, Hospital Universitario 12 de Octubre, 28041 Madrid, Spain
- Department of Medicine, Faculty of Medicine, Complutense University of Madrid, 28040 Madrid, Spain
| | - Cristina Municio
- Group of Neurodegenerative Diseases, Hospital Universitario 12 de Octubre Research Institute (imas12), 28041 Madrid, Spain; (D.A.); (L.C.); (V.C.A.); (J.H.-G.)
- Network Center for Biomedical Research in Neurodegenerative Diseases (CIBERNED), ISCIII, 28031 Madrid, Spain;
- Correspondence: (C.M.); (E.C.); Tel.: +34-918223995 (C.M.); +34-918223995 (E.C.)
| | - Eva Carro
- Network Center for Biomedical Research in Neurodegenerative Diseases (CIBERNED), ISCIII, 28031 Madrid, Spain;
- Neurobiology of Alzheimer’s Disease Unit, Chronic Disease Programme, Instituto de Salud Carlos III, 28222 Majadahonda, Spain
- Correspondence: (C.M.); (E.C.); Tel.: +34-918223995 (C.M.); +34-918223995 (E.C.)
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Skauli N, Savchenko E, Ottersen OP, Roybon L, Amiry-Moghaddam M. Canonical Bone Morphogenetic Protein Signaling Regulates Expression of Aquaporin-4 and Its Anchoring Complex in Mouse Astrocytes. Front Cell Neurosci 2022; 16:878154. [PMID: 35518645 PMCID: PMC9067306 DOI: 10.3389/fncel.2022.878154] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Accepted: 03/22/2022] [Indexed: 11/13/2022] Open
Abstract
Aquaporin-4 (AQP4) is the predominant water channel in the brain; it is enriched in astrocytic foot processes abutting vessels where it is anchored through an interaction with the dystrophin-associated protein (DAP) complex. Enhanced expression with concomitant mislocalization of AQP4 along astrocyte plasma membranes is a hallmark of several neurological conditions. Thus, there is an urgent need to identify which signaling pathways dictate AQP4 microdistribution. Here we show that canonical bone morphogenetic proteins (BMPs), particularly BMP2 and 4, upregulate AQP4 expression in astrocytes and dysregulate the associated DAP complex by differentially affecting its individual members. We further demonstrate the presence of BMP receptors and Smad1/5/9 pathway activation in BMP treated astrocytes. Our analysis of adult mouse brain reveals BMP2 and 4 in neurons and in a subclass of endothelial cells and activated Smad1/5/9 in astrocytes. We conclude that the canonical BMP-signaling pathway might be responsible for regulating the expression of AQP4 and of DAP complex proteins that govern the subcellular compartmentation of this aquaporin.
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Affiliation(s)
- Nadia Skauli
- Division of Anatomy, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Ekaterina Savchenko
- Stem Cell Laboratory for CNS Disease Modeling, Department of Experimental Medical Science, BMC D10, Lund University, Lund, Sweden
| | - Ole Petter Ottersen
- Division of Anatomy, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway.,Karolinska Institutet, Stockholm, Sweden
| | - Laurent Roybon
- Stem Cell Laboratory for CNS Disease Modeling, Department of Experimental Medical Science, BMC D10, Lund University, Lund, Sweden
| | - Mahmood Amiry-Moghaddam
- Division of Anatomy, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
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Uchida Y, Kan H, Sakurai K, Horimoto Y, Hayashi E, Iida A, Okamura N, Oishi K, Matsukawa N. APOE ɛ4 dose associates with increased brain iron and β-amyloid via blood-brain barrier dysfunction. J Neurol Neurosurg Psychiatry 2022; 93:jnnp-2021-328519. [PMID: 35483916 DOI: 10.1136/jnnp-2021-328519] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Accepted: 03/23/2022] [Indexed: 01/09/2023]
Abstract
OBJECTIVE To examine the effect of apolipoprotein E (APOE) ɛ4 dose on blood-brain barrier (BBB) clearance function, evaluated using an advanced MRI technique and analyse its correlation with brain iron and β-amyloid accumulation in the early stages of the Alzheimer's continuum. METHODS In this single-centre observational prospective cohort study, 24 APOE ɛ4 non-carriers, 22 heterozygotes and 20 homozygotes in the early stages of the Alzheimer's continuum were scanned with diffusion-prepared arterial spin labelling, which estimates the water exchange rate across the BBB (kw). Participants also underwent quantitative susceptibility mapping, [11C]Pittsburgh compound B-positron emission tomography and neuropsychological testing. Using an atlas-based approach, we compared the regional kw of the whole brain among the groups and analysed its correlation with the neuroradiological and neuropsychological findings. RESULTS The BBB kw values in the neocortices differed significantly among the groups (APOE ɛ4 non-carriers>heterozygotes>homozygotes). These values correlated with brain iron levels (frontal lobe: r=-0.476, 95% CI=-0.644 to -0.264, p=0.011; medial temporal lobe: r=-0.455, 95% CI=-0.628 to -0.239, p=0.017), β-amyloid loads (frontal lobe: r=-0.504, 95% CI=-0.731 to -0.176, p=0.015; medial temporal lobe: r=-0.452, 95% CI=-0.699 to -0.110, p=0.036) and neuropsychological scores, after adjusting for age, sex and APOE ɛ4 dose. INTERPRETATION Our results suggest that an increased APOE ɛ4 dose is associated with decreased effective brain-waste clearance, such as iron and β-amyloid, through the BBB.
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Affiliation(s)
- Yuto Uchida
- Department of Neurology, Nagoya City University, Nagoya, Japan
- Department of Neurology, Toyokawa City Hospital, Toyokawa, Japan
| | - Hirohito Kan
- Department of Integrated Health Sciences, Nagoya University, Nagoya, Japan
| | - Keita Sakurai
- Department of Radiology, National Center for Geriatrics and Gerontology, Obu, Japan
| | - Yoshihiko Horimoto
- Department of Neurology, Nagoya City Rehabilitation Center Group, Nagoya, Japan
| | - Emi Hayashi
- Department of Radiology, Nagoya City Rehabilitation Center Group, Nagoya, Japan
| | - Akihiko Iida
- Department of Radiology, Nagoya City Rehabilitation Center Group, Nagoya, Japan
| | - Nobuyuki Okamura
- Division of Pharmacology, Faculty of Medicine, Tohoku Medical and Pharmaceutical University, Sendai, Japan
| | - Kenichi Oishi
- Department of Radiology and Radiological Science, Johns Hopkins University, Baltimore, Maryland, USA
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Liu Y, Hu PP, Zhai S, Feng WX, Zhang R, Li Q, Marshall C, Xiao M, Wu T. Aquaporin 4 deficiency eliminates the beneficial effects of voluntary exercise in a mouse model of Alzheimer's disease. Neural Regen Res 2022; 17:2079-2088. [PMID: 35142700 PMCID: PMC8848602 DOI: 10.4103/1673-5374.335169] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Regular exercise has been shown to reduce the risk of Alzheimer's disease (AD). Our previous study showed that the protein aquaporin 4 (AQP4), which is specifically expressed on the paravascular processes of astrocytes, is necessary for glymphatic clearance of extracellular amyloid beta (Aβ) from the brain, which can delay the progression of Alzheimer's disease. However, it is not known whether AQP4-regulated glymphatic clearance of extracellular Aβ is involved in beneficial effects of exercise in AD patients. Our results showed that after 2 months of voluntary wheel exercise, APP/PS1 mice that were 3 months old at the start of the intervention exhibited a decrease in Aβ burden, glial activation, perivascular AQP4 mislocalization, impaired glymphatic transport, synapse protein loss, and learning and memory defects compared with mice not subjected to the exercise intervention. In contrast, APP/PS1 mice that were 7 months old at the start of the intervention exhibited impaired AQP4 polarity and reduced glymphatic clearance of extracellular Aβ, and the above-mentioned impairments were not alleviated after the 2-month exercise intervention. Compared with age-matched APP/PS1 mice, AQP4 knockout APP/PS1 mice had more serious defects in glymphatic function, Aβ plaque deposition, and cognitive impairment, which could not be alleviated after the exercise intervention. These findings suggest that AQP4-dependent glymphatic transport is the neurobiological basis for the beneficial effects of voluntary exercises that protect against the onset of AD.
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Affiliation(s)
- Yun Liu
- Department of Neurology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu Province, China
| | - Pan-Pan Hu
- Jiangsu Province Key Laboratory of Neurodegeneration, Nanjing Medical University; Brain Institute, the Affiliated Nanjing Brain Hospital of Nanjing Medical University, Nanjing, Jiangsu Province, China
| | - Shuang Zhai
- Department of Neurology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu Province, China
| | - Wei-Xi Feng
- Jiangsu Province Key Laboratory of Neurodegeneration, Nanjing Medical University; Brain Institute, the Affiliated Nanjing Brain Hospital of Nanjing Medical University, Nanjing, Jiangsu Province, China
| | - Rui Zhang
- Department of Neurology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu Province, China
| | - Qian Li
- Department of Neurology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu Province, China
| | - Charles Marshall
- College of Health Sciences, University of Kentucky Center of Excellence in Rural Health, Hazard, KY, USA
| | - Ming Xiao
- Jiangsu Province Key Laboratory of Neurodegeneration, Nanjing Medical University; Brain Institute, the Affiliated Nanjing Brain Hospital of Nanjing Medical University, Nanjing, Jiangsu Province, China
| | - Ting Wu
- Department of Neurology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu Province, China
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Dutta A, Das M. Deciphering the Role of Aquaporins in Metabolic Diseases: A Mini Review. Am J Med Sci 2022; 364:148-162. [DOI: 10.1016/j.amjms.2021.10.029] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2020] [Revised: 06/16/2021] [Accepted: 10/21/2021] [Indexed: 12/23/2022]
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Tsiknia AA, Edland SD, Sundermann EE, Reas ET, Brewer JB, Galasko D, Banks SJ. Sex differences in plasma p-tau181 associations with Alzheimer's disease biomarkers, cognitive decline, and clinical progression. Mol Psychiatry 2022; 27:4314-4322. [PMID: 35768637 PMCID: PMC9718670 DOI: 10.1038/s41380-022-01675-8] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Revised: 05/27/2022] [Accepted: 06/10/2022] [Indexed: 02/07/2023]
Abstract
Studies have shown that women on the Alzheimer's disease (AD) continuum have more pathological tau in the brain and cerebrospinal fluid (CSF), than men. Some studies have found that higher levels of tau biomarkers are more strongly associated with clinical AD, cognitive decline and neurodegeneration in women than in men. Despite major developments in the use of plasma tau phosphorylated at threonine 181 (p-tau181) as an AD biomarker, it is unknown whether these sex differences apply to plasma p-tau181. In 1060 Alzheimer's Disease Neuroimaging Initiative (ADNI) participants (47% women, 73.8 ± 7.6 years old), we examined sex differences in plasma p-tau181 levels and their association with other biomarkers, cognitive decline and incident AD. Linear regressions tested for an effect of sex on plasma p-tau181 levels and for plasma p-tau181 × sex interactions on CSF p-tau181, as well as entorhinal cortex tau, cortical amyloid-β (Aβ) deposition, and brain glucose metabolism, quantified using PET imaging. Linear mixed effects models tested for a sex × baseline plasma p-tau181 interaction on change in cognition over time. Finally, Cox models tested for a sex × plasma p-tau181 interaction on the risk of AD dementia in participants who were free of dementia at baseline. Despite similar plasma p-tau181 levels between sexes, women had lower brain glucose metabolism, greater brain Aβ and entorhinal cortex tau deposition, higher CSF p-tau181 and faster cognitive decline in relation to higher baseline plasma p-tau181 levels compared with men. Among Aβ positive, dementia-free participants, women had higher rates of incident AD dementia associated with increasing baseline plasma p-tau181 levels, relative to men. Our results suggest that sex may impact the clinical interpretation of plasma p-tau181 concentrations. If replicated, these findings could have important implications for the use of plasma p-tau181 as an accessible AD biomarker and screening tool for preventive and therapeutic clinical trials.
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Affiliation(s)
- Amaryllis A. Tsiknia
- grid.266100.30000 0001 2107 4242Department of Neurosciences, University of California, San Diego, La Jolla, CA 92093 USA
| | - Steven D. Edland
- grid.266100.30000 0001 2107 4242Department of Neurosciences, University of California, San Diego, La Jolla, CA 92093 USA ,grid.266100.30000 0001 2107 4242Division of Biostatistics, School of Public Health and Human Longevity Science, University of California, San Diego, La Jolla, CA 92093 USA
| | - Erin E. Sundermann
- grid.266100.30000 0001 2107 4242Department of Psychiatry, University of California, San Diego, La Jolla, CA 92093 USA ,grid.410371.00000 0004 0419 2708Research Service, Veterans Affairs San Diego Healthcare System, San Diego, CA 92161 USA
| | - Emilie T. Reas
- grid.266100.30000 0001 2107 4242Department of Neurosciences, University of California, San Diego, La Jolla, CA 92093 USA
| | - James B. Brewer
- grid.266100.30000 0001 2107 4242Department of Neurosciences, University of California, San Diego, La Jolla, CA 92093 USA
| | - Douglas Galasko
- grid.266100.30000 0001 2107 4242Department of Neurosciences, University of California, San Diego, La Jolla, CA 92093 USA
| | - Sarah J. Banks
- grid.266100.30000 0001 2107 4242Department of Neurosciences, University of California, San Diego, La Jolla, CA 92093 USA ,grid.266100.30000 0001 2107 4242Department of Psychiatry, University of California, San Diego, La Jolla, CA 92093 USA
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12
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Gold BT, Shao X, Sudduth TL, Jicha GA, Wilcock DM, Seago ER, Wang DJ. Water exchange rate across the blood-brain barrier is associated with CSF amyloid-β 42 in healthy older adults. Alzheimers Dement 2021; 17:2020-2029. [PMID: 33949773 PMCID: PMC8717840 DOI: 10.1002/alz.12357] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 03/19/2021] [Accepted: 04/07/2021] [Indexed: 01/21/2023]
Abstract
INTRODUCTION We tested if water exchange across the blood-brain barrier (BBB), estimated with a noninvasive magnetic resonance imaging (MRI) technique, is associated with cerebrospinal fluid (CSF) biomarkers of Alzheimer's disease (AD) and neuropsychological function. METHODS Forty cognitively normal older adults (67-86 years old) were scanned with diffusion-prepared, arterial spin labeling (DP-ASL), which estimates water exchange rate across the BBB (kw ). Participants also underwent CSF draw and neuropsychological testing. Multiple linear regression models were run with kw as a predictor of CSF concentrations and neuropsychological scores. RESULTS In multiple brain regions, BBB kw was positively associated with CSF amyloid beta (Aβ)42 concentration levels. BBB kw was only moderately associated with neuropsychological performance. DISCUSSION Our results suggest that low water exchange rate across the BBB is associated with low CSF Aβ42 concentration. These findings suggest that kw may be a promising noninvasive indicator of BBB Aβ clearance functions, a possibility which should be further tested in future research.
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Affiliation(s)
- Brian T. Gold
- Department of NeuroscienceSanders‐Brown Center on AgingLexingtonKentuckyUSA
- Sanders‐Brown Center on AgingLexingtonKentuckyUSA
- Magnetic Resonance Imaging and Spectroscopy CenterCollege of MedicineUniversity of KentuckyLexingtonKentuckyUSA
| | - Xingfeng Shao
- Laboratory of FMRI Technology (LOFT)Mark & Mary Stevens Neuroimaging and Informatics InstituteKeck School of MedicineUniversity of Southern CaliforniaLos AngelesCaliforniaUSA
| | | | - Gregory A. Jicha
- Sanders‐Brown Center on AgingLexingtonKentuckyUSA
- Department of NeurologySanders‐Brown Center on AgingLexingtonKentuckyUSA
| | - Donna M. Wilcock
- Sanders‐Brown Center on AgingLexingtonKentuckyUSA
- Department of PhysiologySanders‐Brown Center on AgingLexingtonKentuckyUSA
| | - Elayna R. Seago
- Department of NeuroscienceSanders‐Brown Center on AgingLexingtonKentuckyUSA
| | - Danny J.J. Wang
- Laboratory of FMRI Technology (LOFT)Mark & Mary Stevens Neuroimaging and Informatics InstituteKeck School of MedicineUniversity of Southern CaliforniaLos AngelesCaliforniaUSA
- Department of NeurologyKeck School of MedicineUniversity of Southern CaliforniaLos AngelesCaliforniaUSA
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13
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Viejo L, Noori A, Merrill E, Das S, Hyman BT, Serrano-Pozo A. Systematic review of human post-mortem immunohistochemical studies and bioinformatics analyses unveil the complexity of astrocyte reaction in Alzheimer's disease. Neuropathol Appl Neurobiol 2021; 48:e12753. [PMID: 34297416 PMCID: PMC8766893 DOI: 10.1111/nan.12753] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Revised: 06/29/2021] [Accepted: 07/12/2021] [Indexed: 12/24/2022]
Abstract
AIMS Reactive astrocytes in Alzheimer's disease (AD) have traditionally been demonstrated by increased glial fibrillary acidic protein (GFAP) immunoreactivity; however, astrocyte reaction is a complex and heterogeneous phenomenon involving multiple astrocyte functions beyond cytoskeletal remodelling. To better understand astrocyte reaction in AD, we conducted a systematic review of astrocyte immunohistochemical studies in post-mortem AD brains followed by bioinformatics analyses on the extracted reactive astrocyte markers. METHODS NCBI PubMed, APA PsycInfo and WoS-SCIE databases were interrogated for original English research articles with the search terms 'Alzheimer's disease' AND 'astrocytes.' Bioinformatics analyses included protein-protein interaction network analysis, pathway enrichment, and transcription factor enrichment, as well as comparison with public human -omics datasets. RESULTS A total of 306 articles meeting eligibility criteria rendered 196 proteins, most of which were reported to be upregulated in AD vs control brains. Besides cytoskeletal remodelling (e.g., GFAP), bioinformatics analyses revealed a wide range of functional alterations including neuroinflammation (e.g., IL6, MAPK1/3/8 and TNF), oxidative stress and antioxidant defence (e.g., MT1A/2A, NFE2L2, NOS1/2/3, PRDX6 and SOD1/2), lipid metabolism (e.g., APOE, CLU and LRP1), proteostasis (e.g., cathepsins, CRYAB and HSPB1/2/6/8), extracellular matrix organisation (e.g., CD44, MMP1/3 and SERPINA3), and neurotransmission (e.g., CHRNA7, GABA, GLUL, GRM5, MAOB and SLC1A2), among others. CTCF and ESR1 emerged as potential transcription factors driving these changes. Comparison with published -omics datasets validated our results, demonstrating a significant overlap with reported transcriptomic and proteomic changes in AD brains and/or CSF. CONCLUSIONS Our systematic review of the neuropathological literature reveals the complexity of AD reactive astrogliosis. We have shared these findings as an online resource available at www.astrocyteatlas.org.
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Affiliation(s)
- Lucía Viejo
- Department of Neurology, Massachusetts General Hospital, Boston, MA, USA.,MassGeneral Institute for Neurodegenerative Disease (MIND), Charlestown, MA, USA.,Departamento de Farmacología y Terapéutica, Universidad Autónoma de Madrid, Madrid, Spain
| | - Ayush Noori
- Department of Neurology, Massachusetts General Hospital, Boston, MA, USA.,MassGeneral Institute for Neurodegenerative Disease (MIND), Charlestown, MA, USA.,Harvard College, Cambridge, MA, USA.,MIND Data Science Lab, Cambridge, MA, USA.,Massachusetts Alzheimer's Disease Research Center, Charlestown, MA, USA
| | - Emily Merrill
- Department of Neurology, Massachusetts General Hospital, Boston, MA, USA.,MassGeneral Institute for Neurodegenerative Disease (MIND), Charlestown, MA, USA.,MIND Data Science Lab, Cambridge, MA, USA
| | - Sudeshna Das
- Department of Neurology, Massachusetts General Hospital, Boston, MA, USA.,MassGeneral Institute for Neurodegenerative Disease (MIND), Charlestown, MA, USA.,MIND Data Science Lab, Cambridge, MA, USA.,Massachusetts Alzheimer's Disease Research Center, Charlestown, MA, USA.,Harvard Medical School, Harvard University, Boston, MA, USA
| | - Bradley T Hyman
- Department of Neurology, Massachusetts General Hospital, Boston, MA, USA.,MassGeneral Institute for Neurodegenerative Disease (MIND), Charlestown, MA, USA.,Massachusetts Alzheimer's Disease Research Center, Charlestown, MA, USA.,Harvard Medical School, Harvard University, Boston, MA, USA
| | - Alberto Serrano-Pozo
- Department of Neurology, Massachusetts General Hospital, Boston, MA, USA.,MassGeneral Institute for Neurodegenerative Disease (MIND), Charlestown, MA, USA.,Massachusetts Alzheimer's Disease Research Center, Charlestown, MA, USA.,Harvard Medical School, Harvard University, Boston, MA, USA
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14
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Park J, Madan M, Chigurupati S, Baek SH, Cho Y, Mughal MR, Yu A, Chan SL, Pattisapu JV, Mattson MP, Jo DG. Neuronal Aquaporin 1 Inhibits Amyloidogenesis by Suppressing the Interaction Between Beta-Secretase and Amyloid Precursor Protein. J Gerontol A Biol Sci Med Sci 2021; 76:23-31. [PMID: 32154567 DOI: 10.1093/gerona/glaa068] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Indexed: 12/15/2022] Open
Abstract
The accumulation of amyloid-β (Aβ) is a characteristic event in the pathogenesis of Alzheimer's disease (AD). Aquaporin 1 (AQP1) is a membrane water channel protein belonging to the AQP family. AQP1 levels are elevated in the cerebral cortex during the early stages of AD, but the role of AQP1 in AD pathogenesis is unclear. We first determined the expression and distribution of AQP1 in brain tissue samples of AD patients and two AD mouse models (3xTg-AD and 5xFAD). AQP1 accumulation was observed in vulnerable neurons in the cerebral cortex of AD patients, and in neurons affected by the Aβ or tau pathology in the 3xTg-AD and 5xFAD mice. AQP1 levels increased in neurons as aging progressed in the AD mouse models. Stress stimuli increased AQP1 in primary cortical neurons. In response to cellular stress, AQP1 appeared to translocate to endocytic compartments of β- and γ-secretase activities. Ectopic expression of AQP1 in human neuroblastoma cells overexpressing amyloid precussir protein (APP) with the Swedish mutations reduced β-secretase (BACE1)-mediated cleavage of APP and reduced Aβ production without altering the nonamyloidogenic pathway. Conversely, knockdown of AQP1 enhanced BACE1 activity and Aβ production. Immunoprecipitation experiments showed that AQP1 decreased the association of BACE1 with APP. Analysis of a human database showed that the amount of Aβ decreases as the expression of AQP1 increases. These results suggest that the upregulation of AQP1 is an adaptive response of neurons to stress that reduces Aβ production by inhibiting the binding between BACE1 and APP.
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Affiliation(s)
- Jinsu Park
- School of Pharmacy, Sungkyunkwan University, Suwon, Korea.,Department of Health Science and Technology, Sungkyunkwan University, Seoul, Korea
| | - Meenu Madan
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando
| | - Srinivasulu Chigurupati
- Bio-Imaging, Division of Neurotoxicology, National Center for Toxicological Research, Jefferson, Arkansas.,Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | | | - Yoonsuk Cho
- School of Pharmacy, Sungkyunkwan University, Suwon, Korea
| | - Mohamed R Mughal
- Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Amin Yu
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando
| | - Sic L Chan
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando
| | - Jogi V Pattisapu
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando
| | - Mark P Mattson
- Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Dong-Gyu Jo
- School of Pharmacy, Sungkyunkwan University, Suwon, Korea.,Department of Health Science and Technology, Sungkyunkwan University, Seoul, Korea.,Biomedical Institute for Convergence, Sungkyunkwan University, Suwon, Korea
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15
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Aquaporin-1 and aquaporin-9 gene variations in sudden infant death syndrome. Int J Legal Med 2021; 135:719-725. [PMID: 33462668 PMCID: PMC8036210 DOI: 10.1007/s00414-020-02493-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Accepted: 12/17/2020] [Indexed: 11/09/2022]
Abstract
Several studies have indicated that a vulnerability in the development and regulation of brain function is involved in sudden infant death syndrome (SIDS). The aim of this study was to investigate the genes encoding the brain aquaporins (AQPs) AQP1 and AQP9 in SIDS. The hypothesis was that specific variants of these genes are part of the genetic vulnerability predisposing infants to sudden unexpected death. The study included 168 SIDS cases with a median age of 15.5 (range 2–52) weeks and 372 adolescent/adult deceased controls with a median age of 44 (range 11–91) years. In the AQP1 gene, the rs17159702 CC/CT genotypes were found to be associated with SIDS (p = 0.02). In the AQP9 gene, the combination of a TT genotype of rs8042354, rs2292711 and rs13329178 was more frequent in SIDS cases than in controls (p = 0.03). In the SIDS group, an association was found between genetic variations in the AQP1 gene and maternal smoking and between the 3xTT combination in the AQP9 gene and being found lifeless in a prone position. In conclusion, this study adds further evidence to the involvement of brain aquaporins in SIDS, suggesting that specific variants of AQP genes constitute a genetic predisposition, making the infant vulnerable to sudden death together with external risk factors and probably other genetic factors.
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16
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Pro-Inflammatory Role of AQP4 in Mice Subjected to Intrastriatal Injections of the Parkinsonogenic Toxin MPP. Cells 2020; 9:cells9112418. [PMID: 33167342 PMCID: PMC7694382 DOI: 10.3390/cells9112418] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Revised: 11/01/2020] [Accepted: 11/02/2020] [Indexed: 12/28/2022] Open
Abstract
Aquaporin-4 (AQP4) is critically involved in brain water and volume homeostasis and has been implicated in a wide range of pathological conditions. Notably, evidence has been accrued to suggest that AQP4 plays a proinflammatory role by promoting release of astrocytic cytokines that activate microglia and other astrocytes. Neuroinflammation is a hallmark of Parkinson’s disease (PD), and we have previously shown that astrocytes in substantia nigra (SN) are enriched in AQP4 relative to cortical astrocytes, and that their complement of AQP4 is further increased following treatment with the parkinsonogenic toxin MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine). Here, we investigated the effect of Aqp4 deletion on microglial activation in mice subjected to unilateral intrastriatal injection of 1-methyl-4-phenylpyridinium (MPP+, the toxic metabolite of MPTP). Our results show that MPP+ injections lead to a pronounced increase in the expression level of microglial activating genes in the ventral mesencephalon of wild type (WT) mice, but not Aqp4−/− mice. We also show, in WT mice, that MPP+ injections cause an upregulation of nigral AQP4 and swelling of astrocytic endfeet. These findings are consistent with the idea that AQP4 plays a pro-inflammatory role in Parkinson’s disease, secondary to the dysregulation of astrocytic volume homeostasis.
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17
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Michalicova A, Majerova P, Kovac A. Tau Protein and Its Role in Blood-Brain Barrier Dysfunction. Front Mol Neurosci 2020; 13:570045. [PMID: 33100967 PMCID: PMC7554615 DOI: 10.3389/fnmol.2020.570045] [Citation(s) in RCA: 72] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Accepted: 08/25/2020] [Indexed: 12/22/2022] Open
Abstract
The blood-brain barrier (BBB) plays a crucial role in maintaining the specialized microenvironment of the central nervous system (CNS). In aging, the stability of the BBB declines and the permeability increases. The list of CNS pathologies involving BBB dysfunction is growing. The opening of the BBB and subsequent infiltration of serum components to the brain can lead to a host of processes resulting in progressive synaptic, neuronal dysfunction, and detrimental neuroinflammatory changes. Such processes have been implicated in different diseases, including vascular dementia, stroke, Alzheimer's disease (AD), Parkinson's disease, multiple sclerosis, amyotrophic lateral sclerosis, hypoxia, ischemia, and diabetes mellitus. The BBB damage is also observed in tauopathies that lack amyloid-β overproduction, suggesting a role for tau in BBB damage. Tauopathies represent a heterogeneous group of around 20 different neurodegenerative diseases characterized by abnormal deposition of the MAPT in cells of the nervous system. Neuropathology of tauopathies is defined as intracellular accumulation of neurofibrillary tangles (NFTs) consisting of aggregated hyper- and abnormal phosphorylation of tau protein and neuroinflammation. Disruption of the BBB found in tauopathies is driven by chronic neuroinflammation. Production of pro-inflammatory signaling molecules such as cytokines, chemokines, and adhesion molecules by glial cells, neurons, and endothelial cells determine the integrity of the BBB and migration of immune cells into the brain. The inflammatory processes promote structural changes in capillaries such as fragmentation, thickening, atrophy of pericytes, accumulation of laminin in the basement membrane, and increased permeability of blood vessels to plasma proteins. Here, we summarize the knowledge about the role of tau protein in BBB structural and functional changes.
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Affiliation(s)
- Alena Michalicova
- Institute of Neuroimmunology, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Petra Majerova
- Institute of Neuroimmunology, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Andrej Kovac
- Institute of Neuroimmunology, Slovak Academy of Sciences, Bratislava, Slovakia.,Department of Pharmacology and Toxicology, The University of Veterinary Medicine and Pharmacy, Kosice, Slovakia
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18
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Tice C, McDevitt J, Langford D. Astrocytes, HIV and the Glymphatic System: A Disease of Disrupted Waste Management? Front Cell Infect Microbiol 2020; 10:523379. [PMID: 33134185 PMCID: PMC7550659 DOI: 10.3389/fcimb.2020.523379] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2019] [Accepted: 08/19/2020] [Indexed: 12/17/2022] Open
Abstract
The discovery of the glial-lymphatic or glymphatic fluid clearance pathway in the rodent brain led researchers to search for a parallel system in humans and to question the implications of this pathway in neurodegenerative diseases. Magnetic resonance imaging studies revealed that several features of the glymphatic system may be present in humans. In both rodents and humans, this pathway promotes the exchange of interstitial fluid (ISF) and cerebrospinal fluid (CSF) through the arterial perivascular spaces into the brain parenchyma. This process is facilitated in part by aquaporin-4 (AQP4) water channels located primarily on astrocytic end feet that abut cerebral endothelial cells of the blood brain barrier. Decreased expression or mislocalization of AQP4 from astrocytic end feet results in decreased interstitial flow, thereby, promoting accumulation of extracellular waste products like hyperphosphorylated Tau (pTau). Accumulation of pTau is a neuropathological hallmark in Alzheimer's disease (AD) and is accompanied by mislocalization of APQ4 from astrocyte end feet to the cell body. HIV infection shares many neuropathological characteristics with AD. Similar to AD, HIV infection of the CNS contributes to abnormal aging with altered AQP4 localization, accumulation of pTau and chronic neuroinflammation. Up to 30% of people with HIV (PWH) suffer from HIV-associated neurocognitive disorders (HAND), and changes in AQP4 may be clinically important as a contributor to cognitive disturbances. In this review, we provide an overview and discussion of the potential contributions of NeuroHIV to glymphatic system functions by focusing on astrocytes and AQP4. Although HAND encompasses a wide range of neurocognitive impairments and levels of neuroinflammation vary among and within PWH, the potential contribution of disruption in AQP4 may be clinically important in some cases. In this review we discuss implications for possible AQP4 disruption on NeuroHIV disease trajectory and how HIV may influence AQP4 function.
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Affiliation(s)
- Caitlin Tice
- Department of Neuroscience, Lewis Katz School of Medicine, Philadelphia, PA, United States
| | - Jane McDevitt
- Department of Kinesiology, College of Public Health at Temple University, Philadelphia, PA, United States
| | - Dianne Langford
- Department of Neuroscience, Lewis Katz School of Medicine, Philadelphia, PA, United States
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19
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Nikpour M, Sharafi A, Hamidi M, Andalib S. Effect of Colloidal Aqueous Solution of Fullerene (C60) in the Presence of a P-Glycoprotein Inhibitor (Verapamil) on Spatial Memory and Hippocampal Expression of Sirtuin6, SELADIN1, and AQP1 Genes in a Rat Model of Alzheimer's Disease. ACS Chem Neurosci 2020; 11:2549-2565. [PMID: 32631043 DOI: 10.1021/acschemneuro.0c00213] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Alzheimer's disease (AD) is one of the most common types of neurodegenerative diseases which is accompanied by irreversible neuronal damage, learning difficulties, memory impairments, and cognitive disorders. The cholinergic system is destroyed during AD pathogenesis, leading to the major symptoms of the disease. Although in severe stages AD is life threatening, to date no absolute treatment has been found for this illness and some palliative options are available. The aim of this study was to investigate the effect of fullerene (C60) aqueous suspension (FAS) on improving spatial memory in amnesic male Wistar rats (weighing 200 ± 20 g) and to further compare the results with that of donepezil (DNPZL) as a standard drug. FAS was prepared via a solvent exchange method. The particle size was in the 119.14 ± 3.38 nm range with polydispersity index of 0.15 ± 0.02 and zeta potential of -12.22 ± 5.98 mV. A simple and high sensitive reversed phase high performance liquid chromatography (HPLC) method was developed to identify the C60 concentration in FAS (21 μg/mL). Efficiencies of drugs were examined in both pretreatment and post-treatment groups of animals to better understand how they participate in affecting AD symptoms. Seeing that previous studies have presented antithetical declarations about whether C60 is a P-glycoprotein (P-gp) substrate, we studied FAS effects in both conditions of the presence and absence of a P-gp inhibitor (verapamil HCl, 25 mg/kg). In order to clarify the molecular mechanisms of action of two drugs, their effects on the expression of three principal genes involved in AD, including Sirtuin6, SELADIN1, and AQP1, and as well as their total antioxidant capacities (TACs) were studied. In order to induce memory impairment, scopolamine HBr (SCOP) was administered for 10 days (2 mg/kg/i.p.). FAS and DNPZL administration regimens were 21 μg/mL, BID (i.p.) and 10 mg/kg (p.o.) for 10 days, respectively. Our results introduce FAS as a promising nanoformulation for improving AD symptoms, especially memory impairment, and further assert that more studies are needed to elucidate C60 and P-gp interaction type.
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Affiliation(s)
- Mehrnoosh Nikpour
- Department of Pharmaceutics, School of Pharmacy, Zanjan University of Medical Sciences, Zanjan, Iran
| | - Ali Sharafi
- Zanjan Pharmaceutical Biotechnology Research Center, Zanjan University of Medical Sciences, Zanjan, Iran
| | - Mehrdad Hamidi
- Zanjan Pharmaceutical Nanotechnology Research Center, Zanjan University of Medical Sciences, Zanjan, Iran
| | - Sina Andalib
- Department of Pharmacology, School of Pharmacy, Zanjan University of Medical Sciences, Zanjan, Iran
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20
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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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21
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Ferrer I, Andrés-Benito P. White matter alterations in Alzheimer's disease without concomitant pathologies. Neuropathol Appl Neurobiol 2020; 46:654-672. [PMID: 32255227 PMCID: PMC7754505 DOI: 10.1111/nan.12618] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Accepted: 03/23/2020] [Indexed: 12/14/2022]
Abstract
Aims Most individuals with AD neuropathological changes have co‐morbidities which have an impact on the integrity of the WM. This study analyses oligodendrocyte and myelin markers in the frontal WM in a series of AD cases without clinical or pathological co‐morbidities. Methods From a consecutive autopsy series, 206 cases had neuropathological changes of AD; among them, only 33 were AD without co‐morbidities. WM alterations were first evaluated in coronal sections of the frontal lobe in every case. Then, RT‐qPCR and immunohistochemistry were carried out in the frontal WM of AD cases without co‐morbidities to analyse the expression of selected oligodendrocyte and myelin markers. Results WM demyelination was more marked in AD with co‐morbidities when compared with AD cases without co‐morbidities. Regarding the later, mRNA expression levels of MBP, PLP1, CNP, MAG, MAL, MOG and MOBP were preserved at stages I–II/0–A when compared with middle‐aged (MA) individuals, but significantly decreased at stages III–IV/0–C. This was accompanied by reduced expression of NG2 and PDGFRA mRNA, reduced numbers of NG2‐, Olig2‐ and HDAC2‐immunoreactive cells and reduced glucose transporter immunoreactivity. Partial recovery of some of these markers occurred at stages V–VI/B–C. Conclusions The present observations demonstrate that co‐morbidities have an impact on WM integrity in the elderly and in AD, and that early alterations in oligodendrocytes and transcription of genes linked to myelin proteins in WM occur in AD cases without co‐morbidities. These are followed by partial recovery attempts at advanced stages. These observations suggest that oligodendrocytopathy is part of AD.
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Affiliation(s)
- I Ferrer
- Department of Pathology and Experimental Therapeutics, University of Barcelona, Barcelona, Spain.,Bellvitge University Hospital, Barcelona, Spain.,Ministry of Economy and Competitiveness, CIBERNED (Network Centre of Biomedical Research of Neurodegenerative Diseases), Institute of Health Carlos III, Barcelona, Spain.,Institute of Neurosciences, University of Barcelona, Barcelona, Spain.,Bellvitge Biomedical Research Institute (IDIBELL), Barcelona, Spain
| | - P Andrés-Benito
- Department of Pathology and Experimental Therapeutics, University of Barcelona, Barcelona, Spain.,Ministry of Economy and Competitiveness, CIBERNED (Network Centre of Biomedical Research of Neurodegenerative Diseases), Institute of Health Carlos III, Barcelona, Spain.,Bellvitge Biomedical Research Institute (IDIBELL), Barcelona, Spain
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22
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Shi Q, Wu YZ, Yang X, Xiao K, Maimaitiming A, Gao LP, Chen C, Gao C, Guo Y, Dong XP. Significant enhanced expressions of aquaporin-1, -4 and -9 in the brains of various prion diseases. Prion 2020; 13:173-184. [PMID: 31814527 PMCID: PMC6746548 DOI: 10.1080/19336896.2019.1660487] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Aquaporins (AQPs) are widely expressed in various types of tissues, among them AQP1, AQP4 and AQP9 are expressed predominately with relatively special distributing features in various brain regions. The aberrant changes of AQP1 and AQP4 have been observed in the brains of Alzheimer disease (AD). To evaluate the underlying alteration of brain AQPs in prion diseases, scrapie strains of 139A, ME7 and S15 infected mice were tested in this study. Western blots revealed markedly increased levels of AQP1, AQP4 and AQP9 in the brain tissues of all tested scrapie-infected mice collected at terminal stage. Analyses of the AQPs levels in the brain tissues collected at different time-points during incubation period showed time-dependent increased in 139A and ME7-infected mice, especially at the middle-late stage. The AQP1 levels also increased in the cortex regions of some human prion diseases, including the patients with sporadic Creutzfeldt-Jakob disease (CJD), fatal familial insomnia (FFI) and G114V genetic CJD (gCJD). Immunohistochemistry (IHC) assays verified that the AQPs-positive cells were astrocyte-like morphologically; meanwhile, numerous various sizes of AQPs-positive particles and dots were also observable in the brain sections of scrapie-infected mice. Immunofluorescent assays (IFAs) illustrated that the signals of AQPs colocalized with those of the GFAP positive proliferative astrocytes, and more interestingly, appeared to overlap also with the signals of PrP in the brains of scrapie-infected mice. Moreover, IHC assays with a commercial doublestain system revealed that distributing areas of AQPs overlapped not only with that of the activated large astrocytes, but also with that of abundantly deposited PrPSc in the brain tissues of scrapie murine models. Our data here propose the solid evidences that the expressions of brain AQP1, AQP4 and AQP9 are all aberrantly enhanced in various murine models of scrapie infection. The closely anatomical association between the accumulated AQPs and deposited PrPSc in the brain tissues indicates that the abnormally increased water channel proteins participate in the pathogenesis of prion diseases.
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Affiliation(s)
- Qi Shi
- State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases (Zhejiang University), National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Yue-Zhang Wu
- State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases (Zhejiang University), National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Xuehua Yang
- State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases (Zhejiang University), National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Kang Xiao
- State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases (Zhejiang University), National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Adalaiti Maimaitiming
- State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases (Zhejiang University), National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Li-Ping Gao
- State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases (Zhejiang University), National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Cao Chen
- State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases (Zhejiang University), National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Chen Gao
- State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases (Zhejiang University), National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Yanjun Guo
- Department of Neurology, Beijing Friendship Hospital, Capital Medical University, Beijing, China
| | - Xiao-Ping Dong
- State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases (Zhejiang University), National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China.,Center for Global Public Health, Chinese Center for Disease Control and Prevention, Beijing, China
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23
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Abbink MR, Kotah JM, Hoeijmakers L, Mak A, Yvon-Durocher G, van der Gaag B, Lucassen PJ, Korosi A. Characterization of astrocytes throughout life in wildtype and APP/PS1 mice after early-life stress exposure. J Neuroinflammation 2020; 17:91. [PMID: 32197653 PMCID: PMC7083036 DOI: 10.1186/s12974-020-01762-z] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Accepted: 02/27/2020] [Indexed: 02/07/2023] Open
Abstract
Background Early-life stress (ES) is an emerging risk factor for later life development of Alzheimer’s disease (AD). We have previously shown that ES modulates amyloid-beta pathology and the microglial response to it in the APPswe/PS1dE9 mouse model. Because astrocytes are key players in the pathogenesis of AD, we studied here if and how ES affects astrocytes in wildtype (WT) and APP/PS1 mice and how these relate to the previously reported amyloid pathology and microglial profile. Methods We induced ES by limiting nesting and bedding material from postnatal days (P) 2–9. We studied in WT mice (at P9, P30, and 6 months) and in APP/PS1 mice (at 4 and 10 months) (i) GFAP coverage, cell density, and complexity in hippocampus (HPC) and entorhinal cortex (EC); (ii) hippocampal gene expression of astrocyte markers; and (iii) the relationship between astrocyte, microglia, and amyloid markers. Results In WT mice, ES increased GFAP coverage in HPC subregions at P9 and decreased it at 10 months. APP/PS1 mice at 10 months exhibited both individual cell as well as clustered GFAP signals. APP/PS1 mice when compared to WT exhibited reduced total GFAP coverage in HPC, which is increased in the EC, while coverage of the clustered GFAP signal in the HPC was increased and accompanied by increased expression of several astrocytic genes. While measured astrocytic parameters in APP/PS1 mice appear not be further modulated by ES, analyzing these in the context of ES-induced alterations to amyloid pathology and microglial shows alterations at both 4 and 10 months of age. Conclusions Our data suggest that ES leads to alterations to the astrocytic response to amyloid-β pathology.
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Affiliation(s)
- Maralinde R Abbink
- Brain Plasticity Group, Center for Neuroscience, Swammerdam Institute for Life Sciences, University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, The Netherlands
| | - Janssen M Kotah
- Brain Plasticity Group, Center for Neuroscience, Swammerdam Institute for Life Sciences, University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, The Netherlands
| | - Lianne Hoeijmakers
- Brain Plasticity Group, Center for Neuroscience, Swammerdam Institute for Life Sciences, University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, The Netherlands
| | - Aline Mak
- Brain Plasticity Group, Center for Neuroscience, Swammerdam Institute for Life Sciences, University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, The Netherlands
| | - Genevieve Yvon-Durocher
- Brain Plasticity Group, Center for Neuroscience, Swammerdam Institute for Life Sciences, University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, The Netherlands
| | - Bram van der Gaag
- Brain Plasticity Group, Center for Neuroscience, Swammerdam Institute for Life Sciences, University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, The Netherlands
| | - Paul J Lucassen
- Brain Plasticity Group, Center for Neuroscience, Swammerdam Institute for Life Sciences, University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, The Netherlands
| | - Aniko Korosi
- Brain Plasticity Group, Center for Neuroscience, Swammerdam Institute for Life Sciences, University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, The Netherlands.
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24
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Transcriptomic and Network Analysis Identifies Shared and Unique Pathways across Dementia Spectrum Disorders. Int J Mol Sci 2020; 21:ijms21062050. [PMID: 32192109 PMCID: PMC7139711 DOI: 10.3390/ijms21062050] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Revised: 03/11/2020] [Accepted: 03/14/2020] [Indexed: 12/12/2022] Open
Abstract
Background: Dementia is a growing public health concern with an estimated prevalence of 50 million people worldwide. Alzheimer’s disease (AD) and vascular and frontotemporal dementias (VaD, FTD), share many clinical, genetical, and pathological features making the diagnosis difficult. Methods: In this study, we compared the transcriptome from the frontal cortex of patients with AD, VaD, and FTD to identify dysregulated pathways. Results: Upregulated genes in AD were enriched in adherens and tight junctions, mitogen-activated protein kinase, and phosphatidylinositol 3-kinase and protein kinase B/Akt signaling pathways, whereas downregulated genes associated with calcium signaling. Upregulated genes in VaD were centered on infectious diseases and nuclear factor kappa beta signaling, whereas downregulated genes are involved in biosynthesis of amino acids and the pentose phosphate pathway. Upregulated genes in FTD were associated with ECM receptor interactions and the lysosome, whereas downregulated genes were involved in glutamatergic synapse and MAPK signaling. The transcription factor KFL4 was shared among the 3 types of dementia. Conclusions: Collectively, we identified similarities and differences in dysregulated pathways and transcription factors among the dementias. The shared pathways and transcription factors may indicate a potential common etiology, whereas the differences may be useful for distinguishing dementias.
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25
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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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26
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Li Q, Aalling NN, Förstera B, Ertürk A, Nedergaard M, Møllgård K, Xavier ALR. Aquaporin 1 and the Na +/K +/2Cl - cotransporter 1 are present in the leptomeningeal vasculature of the adult rodent central nervous system. Fluids Barriers CNS 2020; 17:15. [PMID: 32046744 PMCID: PMC7014736 DOI: 10.1186/s12987-020-0176-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2019] [Accepted: 01/30/2020] [Indexed: 12/26/2022] Open
Abstract
Background The classical view of cerebrospinal fluid (CSF) production posits the choroid plexus as its major source. Although previous studies indicate that part of CSF production occurs in the subarachnoid space (SAS), the mechanisms underlying extra-choroidal CSF production remain elusive. We here investigated the distributions of aquaporin 1 (AQP1) and Na+/K+/2Cl− cotransporter 1 (NKCC1), key proteins for choroidal CSF production, in the adult rodent brain and spinal cord. Methods We have accessed AQP1 distribution in the intact brain using uDISCO tissue clearing technique and by Western blot. AQP1 and NKCC1 cellular localization were accessed by immunohistochemistry in brain and spinal cord obtained from adult rodents. Imaging was performed using light-sheet, confocal and bright field light microscopy. Results We determined that AQP1 is widely distributed in the leptomeningeal vasculature of the intact brain and that its glycosylated isoform is the most prominent in different brain regions. Moreover, AQP1 and NKCC1 show specific distributions in the smooth muscle cell layer of penetrating arterioles and veins in the brain and spinal cord, and in the endothelia of capillaries and venules, restricted to the SAS vasculature. Conclusions Our results shed light on the molecular framework that may underlie extra-choroidal CSF production and we propose that AQP1 and NKCC1 within the leptomeningeal vasculature, specifically at the capillary level, are poised to play a role in CSF production throughout the central nervous system.
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Affiliation(s)
- Qianliang Li
- Center for Translational Neuromedicine, Division of Glial Disease and Therapeutics, University of Copenhagen, 2200, Copenhagen, Denmark
| | - Nadia N Aalling
- Center for Translational Neuromedicine, Division of Glial Disease and Therapeutics, University of Copenhagen, 2200, Copenhagen, Denmark
| | - Benjamin Förstera
- Institute for Stroke and Dementia Research, Klinikum der Universität München, Ludwig Maximilians University of Munich (LMU), 81377, Munich, Germany
| | - Ali Ertürk
- Institute for Stroke and Dementia Research, Klinikum der Universität München, Ludwig Maximilians University of Munich (LMU), 81377, Munich, Germany
| | - Maiken Nedergaard
- Center for Translational Neuromedicine, Division of Glial Disease and Therapeutics, University of Copenhagen, 2200, Copenhagen, Denmark.,Center for Translational Neuromedicine, Division of Glial Disease and Therapeutics, University of Rochester Medical Center, Rochester, NY, 14642, USA
| | - Kjeld Møllgård
- Department of Cellular and Molecular Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, 2200, Copenhagen, Denmark
| | - Anna L R Xavier
- Center for Translational Neuromedicine, Division of Glial Disease and Therapeutics, University of Copenhagen, 2200, Copenhagen, Denmark.
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27
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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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28
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APOE Genotype Specific Effects on the Early Neurodegenerative Sequelae Following Chronic Repeated Mild Traumatic Brain Injury. Neuroscience 2019; 404:297-313. [DOI: 10.1016/j.neuroscience.2019.01.049] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Revised: 01/23/2019] [Accepted: 01/24/2019] [Indexed: 12/14/2022]
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29
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Halsey AM, Conner AC, Bill RM, Logan A, Ahmed Z. Aquaporins and Their Regulation after Spinal Cord Injury. Cells 2018; 7:E174. [PMID: 30340399 PMCID: PMC6210264 DOI: 10.3390/cells7100174] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Revised: 10/13/2018] [Accepted: 10/15/2018] [Indexed: 11/16/2022] Open
Abstract
After injury to the spinal cord, edema contributes to the underlying detrimental pathophysiological outcomes that lead to worsening of function. Several related membrane proteins called aquaporins (AQPs) regulate water movement in fluid transporting tissues including the spinal cord. Within the cord, AQP1, 4 and 9 contribute to spinal cord injury (SCI)-induced edema. AQP1, 4 and 9 are expressed in a variety of cells including astrocytes, neurons, ependymal cells, and endothelial cells. This review discusses some of the recent findings of the involvement of AQP in SCI and highlights the need for further study of these proteins to develop effective therapies to counteract the negative effects of SCI-induced edema.
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Affiliation(s)
- Andrea M Halsey
- Neuroscience and Ophthalmology, Institute of Inflammation and Ageing, University of Birmingham, Birmingham, B15 2TT, UK.
| | - Alex C Conner
- Institute of Clinical Sciences, University of Birmingham, Birmingham B15 2TT, UK.
| | - Roslyn M Bill
- School of Life and Health Sciences, Aston University, Birmingham B4 7ET, UK.
| | - Ann Logan
- Neuroscience and Ophthalmology, Institute of Inflammation and Ageing, University of Birmingham, Birmingham, B15 2TT, UK.
| | - Zubair Ahmed
- Neuroscience and Ophthalmology, Institute of Inflammation and Ageing, University of Birmingham, Birmingham, B15 2TT, UK.
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30
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Perez-Nievas BG, Serrano-Pozo A. Deciphering the Astrocyte Reaction in Alzheimer's Disease. Front Aging Neurosci 2018; 10:114. [PMID: 29922147 PMCID: PMC5996928 DOI: 10.3389/fnagi.2018.00114] [Citation(s) in RCA: 174] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2018] [Accepted: 04/03/2018] [Indexed: 12/24/2022] Open
Abstract
Reactive astrocytes were identified as a component of senile amyloid plaques in the cortex of Alzheimer's disease (AD) patients several decades ago. However, their role in AD pathophysiology has remained elusive ever since, in part owing to the extrapolation of the literature from primary astrocyte cultures and acute brain injury models to a chronic neurodegenerative scenario. Recent accumulating evidence supports the idea that reactive astrocytes in AD acquire neurotoxic properties, likely due to both a gain of toxic function and a loss of their neurotrophic effects. However, the diversity and complexity of this glial cell is only beginning to be unveiled, anticipating that astrocyte reaction might be heterogeneous as well. Herein we review the evidence from mouse models of AD and human neuropathological studies and attempt to decipher the main conundrums that astrocytes pose to our understanding of AD development and progression. We discuss the morphological features that characterize astrocyte reaction in the AD brain, the consequences of astrocyte reaction for both astrocyte biology and AD pathological hallmarks, and the molecular pathways that have been implicated in this reaction.
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Affiliation(s)
| | - Alberto Serrano-Pozo
- Alzheimer's Research Unit, MassGeneral Institute for Neurodegenerative Diseases (MIND), Department of Neurology, Massachusetts General Hospital, Boston, MA, United States
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31
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Yang J, Zhang R, Shi C, Mao C, Yang Z, Suo Z, Torp R, Xu Y. AQP4 Association with Amyloid Deposition and Astrocyte Pathology in the Tg-ArcSwe Mouse Model of Alzheimer's Disease. J Alzheimers Dis 2018; 57:157-169. [PMID: 28222512 DOI: 10.3233/jad-160957] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Amyloid-β deposition in senile plaques is one of the main pathological changes in Alzheimer's disease (AD). We previously reported that aquaporin-4 (AQP4) is redistributed within the astrocytes in cerebral amyloid angiopathy in the tg-ArcSwe mouse model of AD, suggesting that AQP4 may participate in amyloid-β deposition. However, the role of AQP4 in plaque formation is not currently clear. The objective of the current study was to explore the AQP4 distribution within plaques in the tg-ArcSwe mice in more depth by the combined application of immunofluorescence cytochemistry and immunogold electron microscopy. In addition, the astrocyte marker, glial fibrillary acidic protein (GFAP), was studied in association with AQP4. We demonstrated a robust upregulation of AQP4 expression in areas of plaques. Compared to GFAP, AQP4 appeared predominantly at later stages of plaque formation, in older mice, and within the processes of astrocytes. In combination with GFAP, AQP4 differentiated plaques into three progression stages under light microscopy. This suggests that AQP4 expression was associated with amyloid deposition and astrocyte pathology in the Tg-ArcSwe mouse model of AD. This provides novel proof for the involvement of AQP4 in the process of amyloid deposition in AD.
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Affiliation(s)
- Jing Yang
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Henan, China
| | - Rui Zhang
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Henan, China
| | - Changhe Shi
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Henan, China
| | - Chengyuan Mao
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Henan, China
| | - Zhihua Yang
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Henan, China
| | - Zhenhe Suo
- Department of Pathology, The Norwegian Radium Hospital, Oslo University Hospital, Oslo, Norway.,Department of Pathology, The Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Reidun Torp
- Department of Anatomy, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Yuming Xu
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Henan, China
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32
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Boespflug EL, Iliff JJ. The Emerging Relationship Between Interstitial Fluid-Cerebrospinal Fluid Exchange, Amyloid-β, and Sleep. Biol Psychiatry 2018; 83:328-336. [PMID: 29279202 PMCID: PMC5767516 DOI: 10.1016/j.biopsych.2017.11.031] [Citation(s) in RCA: 98] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Revised: 11/21/2017] [Accepted: 11/22/2017] [Indexed: 11/28/2022]
Abstract
Amyloid-β (Aβ) plaques are a key histopathological hallmark of Alzheimer's disease (AD), and soluble Aβ species are believed to play an important role in the clinical development of this disease. Emerging biomarker data demonstrate that Aβ plaque deposition begins decades before the onset of clinical symptoms, suggesting that understanding the biological determinants of the earliest steps in the development of AD pathology may provide key opportunities for AD treatment and prevention. Although a clinical association between sleep disruption and AD has long been appreciated, emerging clinical studies and insights from the basic neurosciences have shed important new light on how sleep and Aβ homeostasis may be connected in the setting of AD. Aβ, like many interstitial solutes, is cleared in part through the exchange of brain interstitial fluid and cerebrospinal fluid along a brain-wide network of perivascular pathways recently termed the glymphatic system. Glymphatic function is primarily a feature of the sleeping brain, rather than the waking brain, and is slowed in the aging and posttraumatic brain. These changes may underlie the diurnal fluctuations in interstitial and cerebrospinal fluid Aβ levels observed in both the rodent and the human. These and other emerging studies suggest that age-related sleep disruption may be one key factor that renders the aging brain vulnerable to Aβ deposition and the development of AD. If this is true, sleep may represent a key modifiable risk factor or therapeutic target in the preclinical phases of AD.
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Affiliation(s)
- Erin L Boespflug
- Department of Neurology, Oregon Health & Science University, Portland, Oregon; Advanced Imaging Research Center, Oregon Health & Science University, Portland, Oregon
| | - Jeffrey J Iliff
- Department of Anesthesiology and Perioperative Medicine, Oregon Health & Science University, Portland, Oregon; Knight Cardiovascular Institute, Oregon Health & Science University, Portland, Oregon.
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33
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Zhang J, Zhan Z, Li X, Xing A, Jiang C, Chen Y, Shi W, An L. Intermittent Fasting Protects against Alzheimer's Disease Possible through Restoring Aquaporin-4 Polarity. Front Mol Neurosci 2017; 10:395. [PMID: 29238290 PMCID: PMC5712566 DOI: 10.3389/fnmol.2017.00395] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Accepted: 11/10/2017] [Indexed: 12/21/2022] Open
Abstract
The impairment of amyloid-β (Aβ) clearance in the brain plays a causative role in Alzheimer's disease (AD). Polarity distribution of aquaporin-4 (AQP4) is important to remove Aβ from brain. AQP4 polarity can be influenced by the ratio of two AQP4 isoforms M1 and M23 (AQP4-M1/M23), however, it is unknown whether the ratio of AQP4-M1/M23 changes in AD. Histone deacetylase 3 has been reported to be significantly increased in AD brain. Moreover, evidence indicated that microRNA-130a (miR-130a) possibly mediates the regulation of histone deacetylase 3 on AQP4-M1/M23 ratio by repressing the transcriptional activity of AQP4-M1 in AD. This study aimed to investigate whether intermittent fasting (IF), increasing the level of an endogenous histone deacetylases inhibitor β-hydroxybutyrate, restores AQP4 polarity via miR-130a mediated reduction of AQP4-M1/M23 ratio in protection against AD. The results showed that IF ameliorated cognitive dysfunction, prevented brain from Aβ deposition, and restored the AQP4 polarity in a mouse model of AD (APP/PS1 double-transgenic mice). Additionally, IF down-regulated the expression of AQP4-M1 and histone deacetylase 3, reduced AQP4-M1/M23 ratio, and increased miR-130a expression in the cerebral cortex of APP/PS1 mice. In vitro, β-hydroxybutyrate was found to down-regulate the expression of AQP4-M1 and histone deacetylase 3, reduce AQP4-M1/M23 ratio, and increase AQP4-M23 and miR-130a expression in 2 μM Aβ-treated U251 cells. Interestingly, on the contrary to the result observed in 2 μM Aβ-treated cells, AQP4 expression was obviously decreased in cells exposed to 10 μM Aβ. miR-130a mimic decreased the expression of AQP4-M1 and the ratio of AQP4-M1/M23, as well as silencing histone deacetylase 3 caused the up-regulation of AQP4 and miR-130a, and the reduction of AQP4-M1/M23 ratio in U251 cells. In conclusion, IF exhibits beneficial effects against AD. The mechanism may be associated with recovery of AQP4 polarity, resulting from the reduction of AQP4-M1/M23 ratio. Furthermore, β-hydroxybutyrate may partly mediate the effect of IF on the reduction of AQP4-M1/M23 ratio in AD, in which miR-130a and histone deacetylase 3 may be implicated.
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Affiliation(s)
- Jingzhu Zhang
- Department of Nutrition and Food Hygiene, School of Public Health, China Medical University, Shenyang, China
| | - Zhipeng Zhan
- Department of Nutrition and Food Hygiene, School of Public Health, China Medical University, Shenyang, China.,Department of Nutrition and Food Hygiene, School of Public Health, Jinzhou Medical University, Jinzhou, China
| | - Xinhui Li
- Department of Nutrition and Food Hygiene, School of Public Health, China Medical University, Shenyang, China
| | - Aiping Xing
- Department of Nutrition and Food Hygiene, School of Public Health, China Medical University, Shenyang, China
| | - Congmin Jiang
- Department of Nutrition and Food Hygiene, School of Public Health, China Medical University, Shenyang, China
| | - Yanqiu Chen
- Department of Nutrition and Food Hygiene, School of Public Health, China Medical University, Shenyang, China
| | - Wanying Shi
- Department of Clinical Nutrition, First Affiliated Hospital, China Medical University, Shenyang, China
| | - Li An
- Department of Nutrition and Food Hygiene, School of Public Health, China Medical University, Shenyang, China
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34
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Hubbard JA, Szu JI, Binder DK. The role of aquaporin-4 in synaptic plasticity, memory and disease. Brain Res Bull 2017; 136:118-129. [PMID: 28274814 DOI: 10.1016/j.brainresbull.2017.02.011] [Citation(s) in RCA: 86] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Revised: 02/27/2017] [Accepted: 02/28/2017] [Indexed: 12/25/2022]
Abstract
Since the discovery of aquaporins, it has become clear that the various mammalian aquaporins play critical physiological roles in water and ion balance in multiple tissues. Aquaporin-4 (AQP4), the principal aquaporin expressed in the central nervous system (CNS, brain and spinal cord), has been shown to mediate CNS water homeostasis. In this review, we summarize new and exciting studies indicating that AQP4 also plays critical and unanticipated roles in synaptic plasticity and memory formation. Next, we consider the role of AQP4 in Alzheimer's disease (AD), amyotrophic lateral sclerosis (ALS), Parkinson's disease (PD), multiple sclerosis (MS), neuromyelitis optica (NMO), epilepsy, traumatic brain injury (TBI), and stroke. Each of these conditions involves changes in AQP4 expression and/or distribution that may be functionally relevant to disease physiology. Insofar as AQP4 is exclusively expressed on astrocytes, these data provide new evidence of "astrocytopathy" in the etiology of diverse neurological diseases.
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Affiliation(s)
- Jacqueline A Hubbard
- Center for Glial-Neuronal Interactions, Division of Biomedical Sciences, School of Medicine, University of California, Riverside, United States
| | - Jenny I Szu
- Center for Glial-Neuronal Interactions, Division of Biomedical Sciences, School of Medicine, University of California, Riverside, United States
| | - Devin K Binder
- Center for Glial-Neuronal Interactions, Division of Biomedical Sciences, School of Medicine, University of California, Riverside, United States.
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35
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Yang C, Huang X, Huang X, Mai H, Li J, Jiang T, Wang X, Lü T. Aquaporin-4 and Alzheimer's Disease. J Alzheimers Dis 2017; 52:391-402. [PMID: 27031475 DOI: 10.3233/jad-150949] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Alzheimer's disease (AD) is the most common form of dementia. Although the pathogenesis of AD remains unclear, AD is thought to result from an imbalance in the production and clearance of amyloid-β protein (Aβ). Aquaporin-4 (AQP4) is the major aquaporin in the mammalian brain, is mostly expressed on astrocytic endfeet, and functions as a water transporter. However, the distribution and expression of AQP4 are altered in both AD clinical populations and animal models. Recent studies have revealed that AQP4 is important to the clearance of Aβ in brain via lymphatic clearance, transcytotic delivery, and glial degradation, as well as to the synaptic function. Thus, AQP4 likely plays an important role in the pathogenesis of AD. Further studies would provide new targets for prevention, ultimately leading to improved treatment options for AD.
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Dossi E, Vasile F, Rouach N. Human astrocytes in the diseased brain. Brain Res Bull 2017; 136:139-156. [PMID: 28212850 PMCID: PMC5766741 DOI: 10.1016/j.brainresbull.2017.02.001] [Citation(s) in RCA: 154] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Revised: 02/08/2017] [Accepted: 02/09/2017] [Indexed: 12/23/2022]
Abstract
Astrocytes are key active elements of the brain that contribute to information processing. They not only provide neurons with metabolic and structural support, but also regulate neurogenesis and brain wiring. Furthermore, astrocytes modulate synaptic activity and plasticity in part by controlling the extracellular space volume, as well as ion and neurotransmitter homeostasis. These findings, together with the discovery that human astrocytes display contrasting characteristics with their rodent counterparts, point to a role for astrocytes in higher cognitive functions. Dysfunction of astrocytes can thereby induce major alterations in neuronal functions, contributing to the pathogenesis of several brain disorders. In this review we summarize the current knowledge on the structural and functional alterations occurring in astrocytes from the human brain in pathological conditions such as epilepsy, primary tumours, Alzheimer's disease, major depressive disorder and Down syndrome. Compelling evidence thus shows that dysregulations of astrocyte functions and interplay with neurons contribute to the development and progression of various neurological diseases. Targeting astrocytes is thus a promising alternative approach that could contribute to the development of novel and effective therapies to treat brain disorders.
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Affiliation(s)
- Elena Dossi
- Neuroglial Interactions in Cerebral Physiopathology, Center for Interdisciplinary Research in Biology, Collège de France, CNRS UMR 7241, INSERM U1050, Labex Memolife, PSL Research University, Paris, France.
| | - Flora Vasile
- Neuroglial Interactions in Cerebral Physiopathology, Center for Interdisciplinary Research in Biology, Collège de France, CNRS UMR 7241, INSERM U1050, Labex Memolife, PSL Research University, Paris, France.
| | - Nathalie Rouach
- Neuroglial Interactions in Cerebral Physiopathology, Center for Interdisciplinary Research in Biology, Collège de France, CNRS UMR 7241, INSERM U1050, Labex Memolife, PSL Research University, Paris, France.
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Abstract
Aquaporins (AQPs ) mediate water flux between the four distinct water compartments in the central nervous system (CNS). In the present chapter, we mainly focus on the expression and function of the 9 AQPs expressed in the CNS, which include five members of aquaporin subfamily: AQP1, AQP4, AQP5, AQP6, and AQP8; three members of aquaglyceroporin subfamily: AQP3, AQP7, and AQP9; and one member of superaquaporin subfamily: AQP11. In addition, AQP1, AQP2 and AQP4 expressed in the peripheral nervous system (PNS) are also reviewed. AQP4, the predominant water channel in the CNS, is involved both in the astrocyte swelling of cytotoxic edema and the resolution of vasogenic edema, and is of pivotal importance in the pathology of brain disorders such as neuromyelitis optica , brain tumors and Alzheimer's disease. Other AQPs are also involved in a variety of important physiological and pathological process in the brain. It has been suggested that AQPs could represent an important target in treatment of brain disorders like cerebral edema. Future investigations are necessary to elucidate the pathological significance of AQPs in the CNS.
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Astrocyte Aquaporin Dynamics in Health and Disease. Int J Mol Sci 2016; 17:ijms17071121. [PMID: 27420057 PMCID: PMC4964496 DOI: 10.3390/ijms17071121] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2016] [Revised: 07/07/2016] [Accepted: 07/07/2016] [Indexed: 02/01/2023] Open
Abstract
The family of aquaporins (AQPs), membrane water channels, consists of diverse types of proteins that are mainly permeable to water; some are also permeable to small solutes, such as glycerol and urea. They have been identified in a wide range of organisms, from microbes to vertebrates and plants, and are expressed in various tissues. Here, we focus on AQP types and their isoforms in astrocytes, a major glial cell type in the central nervous system (CNS). Astrocytes have anatomical contact with the microvasculature, pia, and neurons. Of the many roles that astrocytes have in the CNS, they are key in maintaining water homeostasis. The processes involved in this regulation have been investigated intensively, in particular regulation of the permeability and expression patterns of different AQP types in astrocytes. Three aquaporin types have been described in astrocytes: aquaporins AQP1 and AQP4 and aquaglyceroporin AQP9. The aim here is to review their isoforms, subcellular localization, permeability regulation, and expression patterns in the CNS. In the human CNS, AQP4 is expressed in normal physiological and pathological conditions, but astrocytic expression of AQP1 and AQP9 is mainly associated with a pathological state.
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Astrogliosis: An integral player in the pathogenesis of Alzheimer's disease. Prog Neurobiol 2016; 144:121-41. [PMID: 26797041 DOI: 10.1016/j.pneurobio.2016.01.001] [Citation(s) in RCA: 186] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Revised: 11/10/2015] [Accepted: 01/10/2016] [Indexed: 12/15/2022]
Abstract
Alzheimer's disease is the main cause of dementia in the elderly and begins with a subtle decline in episodic memory followed by a more general decline in overall cognitive abilities. Though the exact trigger for this cascade of events remains unknown the presence of the misfolded amyloid-beta protein triggers reactive gliosis, a prominent neuropathological feature in the brains of Alzheimer's patients. The cytoskeletal and morphological changes of astrogliosis are its evident features, while changes in oxidative stress defense, cholesterol metabolism, and gene transcription programs are less manifest. However, these latter molecular changes may underlie a disruption in homeostatic regulation that keeps the brain environment balanced. Astrocytes in Alzheimer's disease show changes in glutamate and GABA signaling and recycling, potassium buffering, and in cholinergic, purinergic, and calcium signaling. Ultimately the dysregulation of homeostasis maintained by astrocytes can have grave consequences for the stability of microcircuits within key brain regions. Specifically, altered inhibition influenced by astrocytes can lead to local circuit imbalance with farther reaching consequences for the functioning of larger neuronal networks. Healthy astrocytes have a role in maintaining and modulating normal neuronal communication, synaptic physiology and energy metabolism, astrogliosis interferes with these functions. This review considers the molecular and functional changes occurring during astrogliosis in Alzheimer's disease, and proposes that astrocytes are key players in the development of dementia.
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Burnett ME, Johnston HM, Green KN. Structural characterization of the aquaporin inhibitor 2-nicotinamido-1,3,4-thiadiazole. ACTA CRYSTALLOGRAPHICA SECTION C-STRUCTURAL CHEMISTRY 2015; 71:1074-9. [PMID: 26632834 DOI: 10.1107/s2053229615021130] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Accepted: 11/06/2015] [Indexed: 11/10/2022]
Abstract
Nicotinamides are a class of compounds with a wide variety of applications, from use as antimicrobial agents to inhibitors of biological processes. These compounds are also cofactors, which are necessary components of metabolic processes. Structural modification gives rise to the activities observed. Similarly, 1,3,4-thiadiazoles have been shown to possess antioxidant, antimicrobial, or anti-inflammatory biological activity. To take advantage of each of the inherent characteristics of the two aforementioned functional groups, 2-nicotinamido-1,3,4-thiadiazole, C8H6N4OS, was synthesized. Since defining chemical connectivity is paramount in understanding biological activity, in this report, the structural characterization of 2-nicotinamido-1,3,4-thiadiazole has been carried out using X-ray crystallographic methods. The NMR-derived assignments were made possible by utilizing one- (1D) and two-dimensional (2D) NMR techniques. In addition, UV-Visible and IR spectroscopies, and elemental analysis were used to fully characterize the product synthesized by the one-step reaction between nicotinoyl chloride hydrochloride and 2-amino-1,3,4-thiadiazole. Computational parameters related to blood-brain barrier permeability are also presented.
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Affiliation(s)
| | | | - Kayla N Green
- Texas Christian University, Box 299860, Fort Worth, TX 76129, USA
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Kimbrough IF, Robel S, Roberson ED, Sontheimer H. Vascular amyloidosis impairs the gliovascular unit in a mouse model of Alzheimer's disease. Brain 2015; 138:3716-33. [PMID: 26598495 PMCID: PMC5006220 DOI: 10.1093/brain/awv327] [Citation(s) in RCA: 96] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Revised: 08/21/2015] [Accepted: 08/24/2015] [Indexed: 01/08/2023] Open
Abstract
Reduced cerebral blood flow impairs cognitive function and ultimately causes irreparable damage to brain tissue. The gliovascular unit, composed of neural and vascular cells, assures sufficient blood supply to active brain regions. Astrocytes, vascular smooth muscle cells, and pericytes are important players within the gliovascular unit modulating vessel diameters. While the importance of the gliovascular unit and the signals involved in regulating local blood flow to match neuronal activity is now well recognized, surprisingly little is known about this interface in disease. Alzheimer's disease is associated with reduced cerebral blood flow. Here, we studied how the gliovascular unit is affected in a mouse model of Alzheimer's disease, using a combination of ex vivo and in vivo imaging approaches. We specifically labelled vascular amyloid in living mice using the dye methoxy-XO4. We elicited vessel responses ex vivo using either pharmacological stimuli or cell-specific calcium uncaging in vascular smooth muscle cells or astrocytes. Multi-photon in vivo imaging through a cranial window allowed us to complement our ex vivo data in the presence of blood flow after label-free optical activation of vascular smooth muscle cells in the intact brain. We found that vascular amyloid deposits separated astrocyte end-feet from the endothelial vessel wall. High-resolution 3D images demonstrated that vascular amyloid developed in ring-like structures around the vessel circumference, essentially forming a rigid cast. Where vascular amyloid was present, stimulation of astrocytes or vascular smooth muscle cells via ex vivo Ca(2+) uncaging or in vivo optical activation produced only poor vascular responses. Strikingly, vessel segments that were unaffected by vascular amyloid responded to the same extent as vessels from age-matched control animals. We conclude that while astrocytes can still release vasoactive substances, vascular amyloid deposits render blood vessels rigid and reduce the dynamic range of affected vessel segments. These results demonstrate a mechanism that could account in part for the reduction in cerebral blood flow in patients with Alzheimer's disease.media-1vid110.1093/brain/awv327_video_abstractawv327_video_abstract.
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Affiliation(s)
- Ian F Kimbrough
- 1 Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL, USA 2 Center for Glial Biology in Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Stefanie Robel
- 1 Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL, USA 2 Center for Glial Biology in Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Erik D Roberson
- 1 Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL, USA 3 Department of Neurology, University of Alabama at Birmingham, Birmingham, AL, USA 4 Center for Neurodegeneration and Experimental Therapeutics, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Harald Sontheimer
- 1 Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL, USA 2 Center for Glial Biology in Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
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Skjolding AD, Holst AV, Broholm H, Laursen H, Juhler M. Differences in distribution and regulation of astrocytic aquaporin-4 in human and rat hydrocephalic brain. Neuropathol Appl Neurobiol 2015; 39:179-91. [PMID: 22497211 DOI: 10.1111/j.1365-2990.2012.01275.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
AIMS Aquaporin-4 (AQP4) is the most abundant cellular water channel in brain and could be a molecular basis for a cerebrospinal fluid absorption route additional to the arachnoid villi. In the search for 'alternative' cerebrospinal fluid absorption pathways it is important to compare experimental findings with human pathophysiology. This study compares expression of AQP4 in hydrocephalic human brain with human controls and hydrocephalic rat brain. METHODS Cortical biopsies from patients with chronic hydrocephalus (n = 29) were sampled secondary to planned surgical intervention. AQP4 in human hydrocephalic cortex relative to controls was quantified by Western blotting (n = 28). A second biopsy (n = 13) was processed for immunohistochemistry [glial fibrillary acidic protein (GFAP), CD68, CD34 and AQP4] and double immunofluorescence (AQP4 + GFAP and AQP4 + CD34). Brain tissue from human controls and kaolin-induced hydrocephalic rats was processed in parallel. Immunohistochemistry and immunofluorescence were assessed qualitatively. RESULTS Western blotting showed that AQP4 abundance was significantly increased (P < 0.05) in hydrocephalic human brain compared with controls. AQP4 immunoreactivity was present in both white and grey matter. In human brain (hydrocephalic and controls) AQP4 immunoreactivity was found on the entire astrocyte membrane, unlike hydrocephalic rat brain where pronounced endfeet polarization was present. Endothelial AQP4 immunoreactivity was not observed. CONCLUSIONS This study shows a significant increase in astrocytic AQP4 in human hydrocephalic cortex compared with control. Cell type specific expression in astrocytes is conserved between rat and human, although differences of expression in specific membrane domains are seen. This study addresses direct translational aspects from rat to human, hereby emphasizing the relevance and use of models in hydrocephalus research.
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Affiliation(s)
- A D Skjolding
- University Clinic of NeurosurgeryLaboratory of Neuropathology, Copenhagen University Hospital, RigshopitaletDepartment of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - A V Holst
- University Clinic of NeurosurgeryLaboratory of Neuropathology, Copenhagen University Hospital, RigshopitaletDepartment of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - H Broholm
- University Clinic of NeurosurgeryLaboratory of Neuropathology, Copenhagen University Hospital, RigshopitaletDepartment of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - H Laursen
- University Clinic of NeurosurgeryLaboratory of Neuropathology, Copenhagen University Hospital, RigshopitaletDepartment of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - M Juhler
- University Clinic of NeurosurgeryLaboratory of Neuropathology, Copenhagen University Hospital, RigshopitaletDepartment of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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Xu Z, Xiao N, Chen Y, Huang H, Marshall C, Gao J, Cai Z, Wu T, Hu G, Xiao M. Deletion of aquaporin-4 in APP/PS1 mice exacerbates brain Aβ accumulation and memory deficits. Mol Neurodegener 2015; 10:58. [PMID: 26526066 PMCID: PMC4631089 DOI: 10.1186/s13024-015-0056-1] [Citation(s) in RCA: 298] [Impact Index Per Article: 33.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Accepted: 10/29/2015] [Indexed: 12/20/2022] Open
Abstract
Background Preventing or reducing amyloid-beta (Aβ) accumulation in the brain is an important therapeutic strategy for Alzheimer’s disease (AD). Recent studies showed that the water channel aquaporin-4 (AQP4) mediates soluble Aβ clearance from the brain parenchyma along the paravascular pathway. However the direct evidence for roles of AQP4 in the pathophysiology of AD remains absent. Results Here, we reported that the deletion of AQP4 exacerbated cognitive deficits of 12-moth old APP/PS1 mice, with increases in Aβ accumulation, cerebral amyloid angiopathy and loss of synaptic protein and brain-derived neurotrophic factor in the hippocampus and cortex. Furthermore, AQP4 deficiency increased atrophy of astrocytes with significant decreases in interleukin-1 beta and nonsignficant decreases in interleukin-6 and tumor necrosis factor-alpha in hippocampal and cerebral samples. Conclusions These results suggest that AQP4 attenuates Aβ pathogenesis despite its potentially inflammatory side-effects, thus serving as a promising target for treating AD. Electronic supplementary material The online version of this article (doi:10.1186/s13024-015-0056-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Zhiqiang Xu
- Jiangsu Key Laboratory of Neurodegeneration, Nanjing Medical University, 140 Hanzhong Road, Nanjing, Jiangsu, 210029, China
| | - Na Xiao
- Jiangsu Key Laboratory of Neurodegeneration, Nanjing Medical University, 140 Hanzhong Road, Nanjing, Jiangsu, 210029, China
| | - Yali Chen
- Jiangsu Key Laboratory of Neurodegeneration, Nanjing Medical University, 140 Hanzhong Road, Nanjing, Jiangsu, 210029, China
| | - Huang Huang
- Jiangsu Key Laboratory of Neurodegeneration, Nanjing Medical University, 140 Hanzhong Road, Nanjing, Jiangsu, 210029, China
| | - Charles Marshall
- Department of Rehabilitation Sciences, University of Kentucky Center of Excellence in Rural Health, Hazard, KY, USA
| | - Junying Gao
- Jiangsu Key Laboratory of Neurodegeneration, Nanjing Medical University, 140 Hanzhong Road, Nanjing, Jiangsu, 210029, China
| | - Zhiyou Cai
- Department of Neurology, Renmin Hospital, Hubei University of Medicine, Shiyan, Hubei, China
| | - Ting Wu
- Department of Neurology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, China
| | - Gang Hu
- Jiangsu Key Laboratory of Neurodegeneration, Nanjing Medical University, 140 Hanzhong Road, Nanjing, Jiangsu, 210029, China
| | - Ming Xiao
- Jiangsu Key Laboratory of Neurodegeneration, Nanjing Medical University, 140 Hanzhong Road, Nanjing, Jiangsu, 210029, China.
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The Potential Roles of Aquaporin 4 in Alzheimer's Disease. Mol Neurobiol 2015; 53:5300-9. [PMID: 26433375 DOI: 10.1007/s12035-015-9446-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2015] [Accepted: 09/16/2015] [Indexed: 01/28/2023]
Abstract
Aquaporin 4 (AQP4) is the major water channel expressed in the central nervous system (CNS), and it is primarily expressed in astrocytes. It has been studied in various brain pathological conditions. However, the potential for AQP4 to influence Alzheimer's disease (AD) is still unclear. Research regarding AQP4 functions related to AD can be traced back several years and has gradually progressed toward a better understanding of the potential mechanisms. Currently, it has been suggested that AQP4 influences synaptic plasticity, and AQP4 deficiency may impair learning and memory, in part, through glutamate transporter-1 (GLT-1). AQP4 may mediate the clearance of amyloid beta peptides (Aβ). In addition, AQP4 may influence potassium (K(+)) and calcium (Ca(2+)) ion transport, which could play decisive roles in the pathogenesis of AD. Furthermore, AQP4 knockout is involved in neuroinflammation and interferes with AD. To date, no specific therapeutic agents have been developed to inhibit or enhance AQP4. However, experimental results strongly emphasize the importance of this topic for future investigations.
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Erickson MA, Banks WA. Blood-brain barrier dysfunction as a cause and consequence of Alzheimer's disease. J Cereb Blood Flow Metab 2013; 33:1500-13. [PMID: 23921899 PMCID: PMC3790938 DOI: 10.1038/jcbfm.2013.135] [Citation(s) in RCA: 386] [Impact Index Per Article: 35.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Revised: 07/05/2013] [Accepted: 07/09/2013] [Indexed: 12/14/2022]
Abstract
The blood-brain barrier (BBB) plays critical roles in the maintenance of central nervous system (CNS) homeostasis. Dysfunction of the BBB occurs in a number of CNS diseases, including Alzheimer's disease (AD). A prevailing hypothesis in the AD field is the amyloid cascade hypothesis that states that amyloid-β (Aβ) deposition in the CNS initiates a cascade of molecular events that cause neurodegeneration, leading to AD onset and progression. In this review, the participation of the BBB in the amyloid cascade and in other mechanisms of AD neurodegeneration will be discussed. We will specifically focus on three aspects of BBB dysfunction: disruption, perturbation of transporters, and secretion of neurotoxic substances by the BBB. We will also discuss the interaction of the BBB with components of the neurovascular unit in relation to AD and the potential contribution of AD risk factors to aspects of BBB dysfunction. From the results discussed herein, we conclude that BBB dysfunction contributes to AD through a number of mechanisms that could be initiated in the presence or absence of Aβ pathology.
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Affiliation(s)
- Michelle A Erickson
- 1] GRECC, Veterans Affairs Puget Sound Health Care System, Seattle, Washington, USA [2] Division of Gerontology and Geriatric Medicine, Department of Internal Medicine, University of Washington School of Medicine, Seattle, Washington, USA [3] Department of Pathology, School of Dental Medicine, University of Pennsylvania, Seattle, Washington, USA
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Tzartos JS, Stergiou C, Kilidireas K, Zisimopoulou P, Thomaidis T, Tzartos SJ. Anti-aquaporin-1 autoantibodies in patients with neuromyelitis optica spectrum disorders. PLoS One 2013; 8:e74773. [PMID: 24086369 PMCID: PMC3781161 DOI: 10.1371/journal.pone.0074773] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2013] [Accepted: 08/07/2013] [Indexed: 12/02/2022] Open
Abstract
Autoantibodies against aquaporin-4 (AQP4), a water channel in CNS astrocytes, are detected in ∼50–80% of patients with neuromyelitis optica spectrum disorders (NMOsd), characterized by longitudinally extensive transverse myelitis (LETM) and/or optic neuritis. Although these autoantibodies present an invaluable biomarker for NMOsd and for the differential diagnosis of multiple sclerosis (MS), diagnosis of anti-AQP4-seronegative NMOsd remains challenging. We hypothesized that seronegative NMOsd patients might have autoantibodies against aquaporin-1 (AQP1), another water channel in CNS astrocytes. We initially developed a radioimmunoprecipitation assay to search for anti-AQP1 antibodies in sera from 632 individuals. Anti-AQP1 or anti-AQP4 autoantibodies were detected in 16.7% and 12%, respectively, of 348 patients with suspected NMOsd. Anti-AQP1 specificity was confirmed by competition, protein immunoblotting and ELISA assays, whereas epitope localization was studied by immunoadsorption on intact cells expressing AQP1 and peptide mapping experiments. Most anti-AQP1 autoantibodies were of the complement-activating IgG1 subclass and the majority bound to the extracellular domain of AQP1, suggesting a possible pathogenic role. Five out of 42 MS patients had anti-AQP1 antibodies, but 2 of them also had spinal cord lesions, while the anti-AQP1 antibodies in the other 3 bound to the cytoplasmic domain of AQP1. Anti-AQP1 antibodies were not detected in 100 healthy individuals or 142 patients with non-demyelinating neuroimmune diseases. Analysis of 17 anti-AQP1+/anti-AQP4- patients with suspected NMOsd showed that 5 had NMO and 11 had LETM. 12/17 of these sera bound predominantly to the extracellular AQP1 loop-Α. Overall, we found that anti-AQP1 autoantibodies are present in a subgroup of patients with chronic demyelination in the CNS and similarities with anti-AQP4-seronegative NMOsd, offering a novel potential biomarker for CNS demyelination disorders.
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Affiliation(s)
- John S. Tzartos
- Department of Biochemistry, Hellenic Pasteur Institute, Athens, Greece
- Department of Neurology, General Hospital “Red Cross", Athens, Greece
- * E-mail: (JST); (SJT)
| | - Christos Stergiou
- Department of Biochemistry, Hellenic Pasteur Institute, Athens, Greece
| | - Konstantinos Kilidireas
- Department of Neurology, Aeginition Hospital, School of Medicine, National and Kapodistrian University, Athens, Greece
| | | | - Thomas Thomaidis
- Department of Neurology, General Hospital “Red Cross", Athens, Greece
| | - Socrates J. Tzartos
- Department of Biochemistry, Hellenic Pasteur Institute, Athens, Greece
- Department of Pharmacy, University of Patras, Patras, Greece
- * E-mail: (JST); (SJT)
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Zanotto C, Abib RT, Batassini C, Tortorelli LS, Biasibetti R, Rodrigues L, Nardin P, Hansen F, Gottfried C, Leite MC, Gonçalves CA. Non-specific inhibitors of aquaporin-4 stimulate S100B secretion in acute hippocampal slices of rats. Brain Res 2013; 1491:14-22. [DOI: 10.1016/j.brainres.2012.10.065] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2012] [Revised: 10/29/2012] [Accepted: 10/31/2012] [Indexed: 10/27/2022]
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Characteristics of aquaporin expression surrounding senile plaques and cerebral amyloid angiopathy in Alzheimer disease. J Neuropathol Exp Neurol 2012; 71:750-9. [PMID: 22805778 DOI: 10.1097/nen.0b013e3182632566] [Citation(s) in RCA: 96] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Senile plaques (SPs) containing amyloid β peptide (Aβ) 1-42 are the major species present in Alzheimer disease (AD), whereas Aβ1-40 is the major constituent of arteriolar walls affected by cerebral amyloid angiopathy. The water channel proteins astrocytic aquaporin 1 (AQP1) and aquaporin 4 (AQP4) are known to be abnormally expressed in AD brains, but the expression of AQPs surrounding SPs and cerebral amyloid angiopathy has not been described in detail. Here, we investigated whether AQP expression is associated with each species of Aβ deposited in human brains affected by either sporadic or familial AD. Immunohistochemical analysis demonstrated more numerous AQP1-positive reactive astrocytes in the AD cerebral cortex than in controls, located close to Aβ42- or Aβ40-positive SPs. In AD cases, however, AQP1-positive astrocytes were not often observed in Aβ-rich areas, and there was a significant negative correlation between the levels of AQP1 and Aβ42 assessed semiquantitatively. We also found that Aβ plaque-like AQP4 was distributed in association with Aβ42- or Aβ40-positive SPs and that the degree of AQP4 expression around Aβ40-positive vessels was variable. These findings suggest that a defined population of AQP1-positive reactive astrocytes may modify Aβ deposition in the AD brain, whereas the Aβ deposition process might alter astrocytic expression of AQP4.
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Brain water channel proteins in health and disease. Mol Aspects Med 2012; 33:562-78. [DOI: 10.1016/j.mam.2012.03.008] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2012] [Revised: 03/28/2012] [Accepted: 03/31/2012] [Indexed: 02/07/2023]
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Cellular localization of aquaporin-1 in the human and mouse trigeminal systems. PLoS One 2012; 7:e46379. [PMID: 23029502 PMCID: PMC3460814 DOI: 10.1371/journal.pone.0046379] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2012] [Accepted: 08/29/2012] [Indexed: 02/01/2023] Open
Abstract
Previous studies reported that a subpopulation of mouse and rat trigeminal neurons express water channel aquaporin-1 (AQP1). In this study we make a comparative investigation of AQP1 localization in the human and mouse trigeminal systems. Immunohistochemistry and immunofluorescence results showed that AQP1 was localized to the cytoplasm and cell membrane of some medium and small-sized trigeminal neurons. Additionally, AQP1 was found in numerous peripheral trigeminal axons of humans and mice. In the central trigeminal root and brain stem, AQP1 was specifically expressed in astrocytes of humans, but was restricted to nerve fibers within the central trigeminal root and spinal trigeminal tract and nucleus in mice. Furthermore, AQP1 positive nerve fibers were present in the mucosal and submucosal layers of human and mouse oral tissues, but not in the muscular and subcutaneous layers. Fluorogold retrograde tracing demonstrated that AQP1 positive trigeminal neurons innervate the mucosa but not skin of cheek. These results reveal there are similarities and differences in the cellular localization of AQP1 between the human and mouse trigeminal systems. Selective expression of AQP1 in the trigeminal neurons innervating the oral mucosa indicates an involvement of AQP1 in oral sensory transduction.
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