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Huber RE, Babbitt C, Peyton SR. Heterogeneity of brain extracellular matrix and astrocyte activation. J Neurosci Res 2024; 102:e25356. [PMID: 38773875 DOI: 10.1002/jnr.25356] [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: 08/30/2023] [Revised: 04/01/2024] [Accepted: 05/05/2024] [Indexed: 05/24/2024]
Abstract
From the blood brain barrier to the synaptic space, astrocytes provide structural, metabolic, ionic, and extracellular matrix (ECM) support across the brain. Astrocytes include a vast array of subtypes, their phenotypes and functions varying both regionally and temporally. Astrocytes' metabolic and regulatory functions poise them to be quick and sensitive responders to injury and disease in the brain as revealed by single cell sequencing. Far less is known about the influence of the local healthy and aging microenvironments on these astrocyte activation states. In this forward-looking review, we describe the known relationship between astrocytes and their local microenvironment, the remodeling of the microenvironment during disease and injury, and postulate how they may drive astrocyte activation. We suggest technology development to better understand the dynamic diversity of astrocyte activation states, and how basal and activation states depend on the ECM microenvironment. A deeper understanding of astrocyte response to stimuli in ECM-specific contexts (brain region, age, and sex of individual), paves the way to revolutionize how the field considers astrocyte-ECM interactions in brain injury and disease and opens routes to return astrocytes to a healthy quiescent state.
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Affiliation(s)
- Rebecca E Huber
- Department of Chemical Engineering, University of Massachusetts Amherst, Amherst, Massachusetts, USA
| | - Courtney Babbitt
- Department of Biology, University of Massachusetts Amherst, Amherst, Massachusetts, USA
| | - Shelly R Peyton
- Department of Chemical Engineering, University of Massachusetts Amherst, Amherst, Massachusetts, USA
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2
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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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Song J, Li Z, Xue X, Meng J, Zhu W, Hu S, Xu G, Wang L. Neonatal stress disrupts the glymphatic system development and increases the susceptibility to Parkinson's disease in later life. CNS Neurosci Ther 2024; 30:e14587. [PMID: 38421142 PMCID: PMC10851323 DOI: 10.1111/cns.14587] [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: 07/07/2023] [Revised: 12/12/2023] [Accepted: 12/20/2023] [Indexed: 03/02/2024] Open
Abstract
INTRODUCTION Neonatal stress disrupts brain development and increases the risk of neurological disorders later in life. However, the impact of neonatal stress on the development of the glymphatic system and susceptibility to Parkinson's disease (PD) remains largely unknown. METHODS Neonatal maternal deprivation (NMD) was performed on mice for 14 consecutive days to model chronic neonatal stress. Adeno-associated virus expressing A53T-α-synuclein (α-syn) was injected into the substantia nigra to establish PD model mice. Glymphatic activity was determined using in vivo magnetic resonance imaging, ex vivo fluorescence imaging and microplate assay. The transcription and expression of aquaporin-4 (AQP4) and other molecules were evaluated by qPCR, western blotting, and immunofluorescence. Animal's responses to NMD and α-syn overexpression were observed using behavioral tests. RESULTS Glymphatic activity was impaired in adult NMD mice. AQP4 polarization and platelet-derived growth factor B (PDGF-B) signaling were reduced in the frontal cortex and hippocampus of both young and adult NMD mice. Furthermore, exogenous α-syn accumulation was increased and PD-like symptoms were aggravated in adult NMD mice. CONCLUSION The results demonstrated that NMD could disrupt the development of the glymphatic system through PDGF-B signaling and increase the risk of PD later in life, indicating that alleviating neonatal stress could be beneficial in protecting the glymphatic system and reducing susceptibility to neurodegeneration.
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Affiliation(s)
- Jian Song
- Department of Physiology and NeurobiologySuzhou Medical College of Soochow UniversitySuzhouChina
| | - Zhen‐Hua Li
- Department of Physiology and NeurobiologySuzhou Medical College of Soochow UniversitySuzhouChina
| | - Xin‐Yu Xue
- Department of Physiology and NeurobiologySuzhou Medical College of Soochow UniversitySuzhouChina
| | - Jing‐Cai Meng
- Department of Physiology and NeurobiologySuzhou Medical College of Soochow UniversitySuzhouChina
| | - Wen‐Xin Zhu
- Department of Physiology and NeurobiologySuzhou Medical College of Soochow UniversitySuzhouChina
| | - Shufen Hu
- Jiangsu Key Laboratory of Neuropsychiatric Diseases, Institute of NeuroscienceSoochow UniversitySuzhouChina
| | - Guang‐Yin Xu
- Jiangsu Key Laboratory of Neuropsychiatric Diseases, Institute of NeuroscienceSoochow UniversitySuzhouChina
| | - Lin‐Hui Wang
- Department of Physiology and NeurobiologySuzhou Medical College of Soochow UniversitySuzhouChina
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Huang H, Lin L, Wu T, Wu C, Zhou L, Li G, Su F, Liang F, Guo W, Chen W, Jiang Q, Guan Y, Li X, Xu P, Zhang Y, Smith W, Pei Z. Phosphorylation of AQP4 by LRRK2 R1441G impairs glymphatic clearance of IFNγ and aggravates dopaminergic neurodegeneration. NPJ Parkinsons Dis 2024; 10:31. [PMID: 38296953 PMCID: PMC10831045 DOI: 10.1038/s41531-024-00643-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Accepted: 01/16/2024] [Indexed: 02/02/2024] Open
Abstract
Aquaporin-4 (AQP4) is essential for normal functioning of the brain's glymphatic system. Impaired glymphatic function is associated with neuroinflammation. Recent clinical evidence suggests the involvement of glymphatic dysfunction in LRRK2-associated Parkinson's disease (PD); however, the precise mechanism remains unclear. The pro-inflammatory cytokine interferon (IFN) γ interacts with LRRK2 to induce neuroinflammation. Therefore, we examined the AQP4-dependent glymphatic system's role in IFNγ-mediated neuroinflammation in LRRK2-associated PD. We found that LRRK2 interacts with and phosphorylates AQP4 in vitro and in vivo. AQP4 phosphorylation by LRRK2 R1441G induced AQP4 depolarization and disrupted glymphatic IFNγ clearance. Exogeneous IFNγ significantly increased astrocyte expression of IFNγ receptor, amplified AQP4 depolarization, and exacerbated neuroinflammation in R1441G transgenic mice. Conversely, inhibiting LRRK2 restored AQP4 polarity, improved glymphatic function, and reduced IFNγ-mediated neuroinflammation and dopaminergic neurodegeneration. Our findings establish a link between LRRK2-mediated AQP4 phosphorylation and IFNγ-mediated neuroinflammation in LRRK2-associated PD, guiding the development of LRRK2 targeting therapy.
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Affiliation(s)
- Heng Huang
- Department of Neurology, The First Affiliated Hospital, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Diagnosis and Treatment of Major Neurological Diseases, National Key Clinical Department and Key Discipline of Neurology, Guangzhou, China
| | - Lishan Lin
- Department of Neurology, The First Affiliated Hospital, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Diagnosis and Treatment of Major Neurological Diseases, National Key Clinical Department and Key Discipline of Neurology, Guangzhou, China
| | - Tengteng Wu
- Department of Neurology, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
| | - Cheng Wu
- Guangdong Cardiovascular Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Leping Zhou
- Department of Neurology, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
| | - Ge Li
- Guangdong Provincial Key Laboratory of Laboratory Animals, Guangdong Laboratory Animals Monitoring Institute, Guangzhou, China
| | - Fengjuan Su
- Department of Neurology, The First Affiliated Hospital, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Diagnosis and Treatment of Major Neurological Diseases, National Key Clinical Department and Key Discipline of Neurology, Guangzhou, China
| | - Fengyin Liang
- Department of Neurology, The First Affiliated Hospital, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Diagnosis and Treatment of Major Neurological Diseases, National Key Clinical Department and Key Discipline of Neurology, Guangzhou, China
| | - Wenyuan Guo
- Department of Neurology, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
| | - Weineng Chen
- Department of Neurology, The First Affiliated Hospital, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Diagnosis and Treatment of Major Neurological Diseases, National Key Clinical Department and Key Discipline of Neurology, Guangzhou, China
| | - Qiuhong Jiang
- Department of Neurology, The First Affiliated Hospital, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Diagnosis and Treatment of Major Neurological Diseases, National Key Clinical Department and Key Discipline of Neurology, Guangzhou, China
| | - Yalun Guan
- Guangdong Provincial Key Laboratory of Laboratory Animals, Guangdong Laboratory Animals Monitoring Institute, Guangzhou, China
| | - Xuejiao Li
- Guangdong Provincial Key Laboratory of Laboratory Animals, Guangdong Laboratory Animals Monitoring Institute, Guangzhou, China
| | - Pingyi Xu
- Department of Neurology, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
| | - Yu Zhang
- Guangdong Provincial Key Laboratory of Laboratory Animals, Guangdong Laboratory Animals Monitoring Institute, Guangzhou, China
| | - Wanli Smith
- Department of Psychiatry, Division of Neurobiology, Johns Hopkins University School of Medicine, Baltimore, MD, 21287, USA
| | - Zhong Pei
- Department of Neurology, The First Affiliated Hospital, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Diagnosis and Treatment of Major Neurological Diseases, National Key Clinical Department and Key Discipline of Neurology, Guangzhou, China.
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Mueller SM, McFarland White K, Fass SB, Chen S, Shi Z, Ge X, Engelbach JA, Gaines SH, Bice AR, Vasek MJ, Garbow JR, Culver JP, Martinez-Lozada Z, Cohen-Salmon M, Dougherty JD, Sapkota D. Evaluation of gliovascular functions of AQP4 readthrough isoforms. Front Cell Neurosci 2023; 17:1272391. [PMID: 38077948 PMCID: PMC10701521 DOI: 10.3389/fncel.2023.1272391] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Accepted: 10/06/2023] [Indexed: 12/20/2023] Open
Abstract
Aquaporin-4 (AQP4) is a water channel protein that links the astrocytic endfeet to the blood-brain barrier (BBB) and regulates water and potassium homeostasis in the brain, as well as the glymphatic clearance of waste products that would otherwise potentiate neurological diseases. Recently, translational readthrough was shown to generate a C-terminally extended variant of AQP4, known as AQP4x, which preferentially localizes around the BBB through interaction with the scaffolding protein α-syntrophin, and loss of AQP4x disrupts waste clearance from the brain. To investigate the function of AQP4x, we generated a novel AQP4 mouse line (AllX) to increase relative levels of the readthrough variant above the ~15% of AQP4 in the brain of wild-type (WT) mice. We validated the line and assessed characteristics that are affected by the presence of AQP4x, including AQP4 and α-syntrophin localization, integrity of the BBB, and neurovascular coupling. We compared AllXHom and AllXHet mice to WT and to previously characterized AQP4 NoXHet and NoXHom mice, which cannot produce AQP4x. An increased dose of AQP4x enhanced perivascular localization of α-syntrophin and AQP4, while total protein expression of the two was unchanged. However, at 100% readthrough, AQP4x localization and the formation of higher order complexes were disrupted. Electron microscopy showed that overall blood vessel morphology was unchanged except for an increased proportion of endothelial cells with budding vesicles in NoXHom mice, which may correspond to a leakier BBB or altered efflux that was identified in NoX mice using MRI. These data demonstrate that AQP4x plays a small but measurable role in maintaining BBB integrity as well as recruiting structural and functional support proteins to the blood vessel. This also establishes a new set of genetic tools for quantitatively modulating AQP4x levels.
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Affiliation(s)
- Shayna M. Mueller
- Department of Genetics, Washington University School of Medicine, Saint Louis, MO, United States
- Department of Psychiatry, Washington University School of Medicine, Saint Louis, MO, United States
| | - Kelli McFarland White
- Department of Genetics, Washington University School of Medicine, Saint Louis, MO, United States
- Department of Psychiatry, Washington University School of Medicine, Saint Louis, MO, United States
| | - Stuart B. Fass
- Department of Genetics, Washington University School of Medicine, Saint Louis, MO, United States
- Department of Psychiatry, Washington University School of Medicine, Saint Louis, MO, United States
| | - Siyu Chen
- Department of Genetics, Washington University School of Medicine, Saint Louis, MO, United States
- Department of Psychiatry, Washington University School of Medicine, Saint Louis, MO, United States
- Department of Radiology, Washington University School of Medicine, Saint Louis, MO, United States
| | - Zhan Shi
- Department of Biological Sciences, University of Texas at Dallas, Richardson, TX, United States
| | - Xia Ge
- Department of Radiology, Washington University School of Medicine, Saint Louis, MO, United States
- Intellectual and Developmental Disabilities Research Center, Washington University School of Medicine, Saint Louis, MO, United States
| | - John A. Engelbach
- Department of Radiology, Washington University School of Medicine, Saint Louis, MO, United States
- Intellectual and Developmental Disabilities Research Center, Washington University School of Medicine, Saint Louis, MO, United States
| | - Seana H. Gaines
- Department of Radiology, Washington University School of Medicine, Saint Louis, MO, United States
| | - Annie R. Bice
- Department of Radiology, Washington University School of Medicine, Saint Louis, MO, United States
| | - Michael J. Vasek
- Department of Genetics, Washington University School of Medicine, Saint Louis, MO, United States
- Department of Psychiatry, Washington University School of Medicine, Saint Louis, MO, United States
| | - Joel R. Garbow
- Department of Radiology, Washington University School of Medicine, Saint Louis, MO, United States
- Intellectual and Developmental Disabilities Research Center, Washington University School of Medicine, Saint Louis, MO, United States
| | - Joseph P. Culver
- Department of Radiology, Washington University School of Medicine, Saint Louis, MO, United States
- Department of Physics, Washington University in St. Louis, Saint Louis, MO, United States
- Department of Biomedical Engineering, Washington University in St. Louis, Saint Louis, MO, United States
- Department of Neuroscience, Washington University School of Medicine, Saint Louis, MO, United States
- Imaging Science PhD Program, Washington University in St. Louis, Saint Louis, MO, United States
| | - Zila Martinez-Lozada
- Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA, United States
| | - Martine Cohen-Salmon
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, The National Centre for Scientific Research (CNRS), National Institute of Health and Medical Research (INSERM), Université PSL, Paris, France
| | - Joseph D. Dougherty
- Department of Genetics, Washington University School of Medicine, Saint Louis, MO, United States
- Department of Psychiatry, Washington University School of Medicine, Saint Louis, MO, United States
- Intellectual and Developmental Disabilities Research Center, Washington University School of Medicine, Saint Louis, MO, United States
| | - Darshan Sapkota
- Department of Biological Sciences, University of Texas at Dallas, Richardson, TX, United States
- Department of Neuroscience, University of Texas at Dallas, Richardson, TX, United States
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Martinez-Lozada Z, Todd FW, Schober AL, Krizman E, Robinson MB, Murai KK. Cooperative and competitive regulation of the astrocytic transcriptome by neurons and endothelial cells: Impact on astrocyte maturation. J Neurochem 2023; 167:52-75. [PMID: 37525469 PMCID: PMC10543513 DOI: 10.1111/jnc.15908] [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: 03/01/2023] [Revised: 06/19/2023] [Accepted: 06/20/2023] [Indexed: 08/02/2023]
Abstract
Astrocytes have essential roles in central nervous system (CNS) health and disease. During development, immature astrocytes show complex interactions with neurons, endothelial cells, and other glial cell types. Our work and that of others have shown that these interactions are important for astrocytic maturation. However, whether and how these cells work together to control this process remains poorly understood. Here, we test the hypothesis that cooperative interactions of astrocytes with neurons and endothelial cells promote astrocytic maturation. Astrocytes were cultured alone, with neurons, endothelial cells, or a combination of both. This was followed by astrocyte sorting, RNA sequencing, and bioinformatic analysis to detect transcriptional changes. Across culture configurations, 7302 genes were differentially expressed by 4 or more fold and organized into 8 groups that demonstrate cooperative and antagonist effects of neurons and endothelia on astrocytes. We also discovered that neurons and endothelial cells caused splicing of 200 and 781 mRNAs, respectively. Changes in gene expression were validated using quantitative PCR, western blot (WB), and immunofluorescence analysis. We found that the transcriptomic data from the three-culture configurations correlated with protein expression of three representative targets (FAM107A, GAT3, and GLT1) in vivo. Alternative splicing results also correlated with cortical tissue isoform representation of a target (Fibronectin 1) at different developmental stages. By comparing our results to published transcriptomes of immature and mature astrocytes, we found that neurons or endothelia shift the astrocytic transcriptome toward a mature state and that the presence of both cell types has a greater effect on maturation than either cell alone. These results increase our understanding of cellular interactions/pathways that contribute to astrocytic maturation. They also provide insight into how alterations to neurons and/or endothelial cells may alter astrocytes with implications for astrocytic changes in CNS disorders and diseases.
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Affiliation(s)
- Zila Martinez-Lozada
- Departments of Pediatrics and Systems Pharmacology & Translational Therapeutics, The Children’s Hospital of Philadelphia, University of Pennsylvania, Philadelphia, PA, USA, 19104-4318
| | - Farmer W. Todd
- Centre for Research in Neuroscience, Department of Neurology & Neurosurgery, Brain Repair and Integrative Neuroscience Program, The Research Institute of the McGill University Health Centre, Montreal General Hospital, Montreal, Quebec, Canada H3G 1A4
| | - Alexandra L. Schober
- Centre for Research in Neuroscience, Department of Neurology & Neurosurgery, Brain Repair and Integrative Neuroscience Program, The Research Institute of the McGill University Health Centre, Montreal General Hospital, Montreal, Quebec, Canada H3G 1A4
| | - Elizabeth Krizman
- Departments of Pediatrics and Systems Pharmacology & Translational Therapeutics, The Children’s Hospital of Philadelphia, University of Pennsylvania, Philadelphia, PA, USA, 19104-4318
| | - Michael B. Robinson
- Departments of Pediatrics and Systems Pharmacology & Translational Therapeutics, The Children’s Hospital of Philadelphia, University of Pennsylvania, Philadelphia, PA, USA, 19104-4318
| | - Keith K. Murai
- Centre for Research in Neuroscience, Department of Neurology & Neurosurgery, Brain Repair and Integrative Neuroscience Program, The Research Institute of the McGill University Health Centre, Montreal General Hospital, Montreal, Quebec, Canada H3G 1A4
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Tapp ZM, Ren C, Palmer K, Kumar J, Atluri RR, Fitzgerald J, Velasquez J, Godbout J, Sheridan J, Kokiko-Cochran ON. Divergent Spatial Learning, Enhanced Neuronal Transcription, and Blood-Brain Barrier Disruption Develop During Recovery from Post-Injury Sleep Fragmentation. Neurotrauma Rep 2023; 4:613-626. [PMID: 37752925 PMCID: PMC10518692 DOI: 10.1089/neur.2023.0018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/28/2023] Open
Abstract
Traumatic brain injury (TBI) causes pathophysiology that may significantly decrease quality of life over time. A major propagator of this response is chronic, maladaptive neuroinflammation, which can be exacerbated by stressors such as sleep fragmentation (SF). This study determined whether post-TBI SF had lasting behavioral and inflammatory effects even with a period of recovery. To test this, male and female mice received a moderate lateral fluid percussion TBI or sham surgery. Half the mice were left undisturbed, and half were exposed to daily SF for 30 days. All mice were then undisturbed between 30 and 60 days post-injury (DPI), allowing mice to recover from SF (SF-R). SF-R did not impair global Barnes maze performance. Nonetheless, TBI SF-R mice displayed retrogression in latency to reach the goal box within testing days. These nuanced behavioral changes in TBI SF-R mice were associated with enhanced expression of neuronal processing/signaling genes and indicators of blood-brain barrier (BBB) dysfunction. Aquaporin-4 (AQP4) expression, a marker of BBB integrity, was differentially altered by TBI and TBI SF-R. For example, TBI enhanced cortical AQP4 whereas TBI SF-R mice had the lowest cortical expression of perivascular AQP4, dysregulated AQP4 polarization, and the highest number of CD45+ cells in the ipsilateral cortex. Altogether, post-TBI SF caused lasting, divergent behavioral responses associated with enhanced expression of neuronal transcription and BBB disruption even after a period of recovery from SF. Understanding lasting impacts from post-TBI stressors can better inform both acute and chronic post-injury care to improve long-term outcome post-TBI.
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Affiliation(s)
- Zoe M. Tapp
- Department of Neuroscience, College of Medicine, College of Dentistry, The Ohio State University, Columbus, Ohio, USA
| | - Cindy Ren
- Department of Neuroscience, College of Medicine, College of Dentistry, The Ohio State University, Columbus, Ohio, USA
| | - Kelsey Palmer
- Department of Neuroscience, College of Medicine, College of Dentistry, The Ohio State University, Columbus, Ohio, USA
| | - Julia Kumar
- Department of Neuroscience, College of Medicine, College of Dentistry, The Ohio State University, Columbus, Ohio, USA
| | - Ravitej R. Atluri
- Department of Neuroscience, College of Medicine, College of Dentistry, The Ohio State University, Columbus, Ohio, USA
| | - Julie Fitzgerald
- Department of Neuroscience, College of Medicine, College of Dentistry, The Ohio State University, Columbus, Ohio, USA
| | - John Velasquez
- Department of Neuroscience, College of Medicine, College of Dentistry, The Ohio State University, Columbus, Ohio, USA
| | - Jonathan Godbout
- Department of Neuroscience, College of Medicine, College of Dentistry, The Ohio State University, Columbus, Ohio, USA
- Chronic Brain Injury Program, College of Dentistry, The Ohio State University, Columbus, Ohio, USA
- Institute for Behavioral Medicine Research, Neurological Institute, College of Dentistry, The Ohio State University, Columbus, Ohio, USA
| | - John Sheridan
- Department of Neuroscience, College of Medicine, College of Dentistry, The Ohio State University, Columbus, Ohio, USA
- Chronic Brain Injury Program, College of Dentistry, The Ohio State University, Columbus, Ohio, USA
- Division of Biosciences, College of Dentistry, The Ohio State University, Columbus, Ohio, USA
| | - Olga N. Kokiko-Cochran
- Department of Neuroscience, College of Medicine, College of Dentistry, The Ohio State University, Columbus, Ohio, USA
- Chronic Brain Injury Program, College of Dentistry, The Ohio State University, Columbus, Ohio, USA
- Institute for Behavioral Medicine Research, Neurological Institute, College of Dentistry, The Ohio State University, Columbus, Ohio, USA
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8
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Maroli N. Aquaporin-4 Mediated Aggregation of Alzheimer's Amyloid β-Peptide. ACS Chem Neurosci 2023; 14:2683-2698. [PMID: 37486638 DOI: 10.1021/acschemneuro.3c00233] [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] [Indexed: 07/25/2023] Open
Abstract
Clearance of Alzheimer's amyloid oligomers from the brain is crucial for preventing cell toxicity. Dementia complications arise as a result of apoptosis, which is caused by peptide plaques on the lipid surface of cells. Here, we employed all-atom and coarse-grained molecular dynamics simulations to investigate the aggregation of amyloid peptides at the lipid surface and the role of aquaporin-4 (AQP4) in facilitating peptide clearance from astrocytes. The network of protein-protein interactions through text mining revealed that the expression of AQP4 and amyloid aggregation were strongly correlated. It has also been revealed that the role of aquaporins in the etiology of Alzheimer's disease involves several interconnected proteins and pathways. The nature of aggregation at the surface of the 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) lipid bilayer was revealed by the interaction of amyloid oligomers. The membrane-bound pore region of AQP4 interacts with the peptide and slows its aggregation. This interaction maintains the helical content of the peptide while lowering its toxicity at the lipid surface. The hydrophobicity of the peptide also decreased because of these interactions, which may help in the removal of the peptide from astrocytes. Long-term coarse-grained MD simulations demonstrated different features of oligomer aggregation at the surface and strong oligomer attraction to AQP4, which inhibited aggregation. Additionally, the water dynamics of aquaporins demonstrate how the selectivity filter is broken to disrupt water flow. Our findings also provide insight into the physiological alterations in brain tissue associated with Alzheimer's disease, including water retention and increased water flow in the CSF. Furthermore, in vitro thioflavin fluorescence spectroscopy revealed a slower aggregation of the peptide in the presence of AQP4.
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Affiliation(s)
- Nikhil Maroli
- Computational Biology Division, DRDO Center for Life Science, Bharathiar University Campus, Coimbatore 641046, Tamil Nadu, India
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9
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Mueller SM, White KM, Fass SB, Chen S, Shi Z, Ge X, Engelbach JA, Gaines SH, Bice AR, Vasek MJ, Garbow JR, Culver JP, Zila Martinez-Lozada, Cohen-Salmon M, Dougherty JD, Sapkota D. Evaluation of gliovascular functions of Aqp4 readthrough isoforms. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.21.549379. [PMID: 37546949 PMCID: PMC10401933 DOI: 10.1101/2023.07.21.549379] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/08/2023]
Abstract
Aquaporin-4 (AQP4) is a water channel protein that links astrocytic endfeet to the blood-brain barrier (BBB) and regulates water and potassium homeostasis in the brain, as well as the glymphatic clearance of waste products that would otherwise potentiate neurological diseases. Recently, translational readthrough was shown to generate a C-terminally extended variant of AQP4, known as AQP4x, that preferentially localizes around the BBB through interaction with the scaffolding protein α-syntrophin, and loss of AQP4x disrupts waste clearance from the brain. To investigate the function of AQP4x, we generated a novel mouse AQP4 line (AllX) to increase relative levels of the readthrough variant above the ~15% of AQP4 in the brain of wildtype (WT) mice. We validated the line and assessed characteristics that are affected by the presence of AQP4x, including AQP4 and α-syntrophin localization, integrity of the BBB, and neurovascular coupling. We compared AllXHom and AllXHet mice to wildtype, and to previously characterized AQP4 NoXHet and NoXHom mice, which cannot produce AQP4x. Increased dose of AQP4x enhanced perivascular localization of α-syntrophin and AQP4, while total protein expression of the two were unchanged. However, at 100% readthrough, AQP4x localization and formation of higher-order complexes was disrupted. Electron microscopy showed that overall blood vessel morphology was unchanged except for increased endothelial cell vesicles in NoXHom mice, which may correspond to a leakier BBB or altered efflux that was identified in NoX mice using MRI. These data demonstrate that AQP4x plays a small but measurable role in maintaining BBB integrity as well as recruiting structural and functional support proteins to the blood vessel. This also establishes a new set of genetic tools for quantitatively modulating AQP4x levels.
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Affiliation(s)
- Shayna M. Mueller
- Department of Genetics, Washington University School of Medicine, Saint Louis, MO 63110, USA
- Department of Psychiatry, Washington University School of Medicine, Saint Louis, MO 63110, USA
| | - Kelli McFarland White
- Department of Genetics, Washington University School of Medicine, Saint Louis, MO 63110, USA
- Department of Psychiatry, Washington University School of Medicine, Saint Louis, MO 63110, USA
| | - Stuart B. Fass
- Department of Genetics, Washington University School of Medicine, Saint Louis, MO 63110, USA
- Department of Psychiatry, Washington University School of Medicine, Saint Louis, MO 63110, USA
| | - Siyu Chen
- Department of Genetics, Washington University School of Medicine, Saint Louis, MO 63110, USA
- Department of Psychiatry, Washington University School of Medicine, Saint Louis, MO 63110, USA
- Department of Radiology, Washington University School of Medicine, Saint Louis, MO 63110, USA
| | - Zhan Shi
- Department of Biological Sciences, University of Texas at Dallas, Richardson, Texas 75080, USA
| | - Xia Ge
- Department of Radiology, Washington University School of Medicine, Saint Louis, MO 63110, USA
- Intellectual and Development Developmental Disabilities Research Center, Washington University School of Medicine, Saint Louis, MO 63110, USA
| | - John A. Engelbach
- Department of Radiology, Washington University School of Medicine, Saint Louis, MO 63110, USA
- Intellectual and Development Developmental Disabilities Research Center, Washington University School of Medicine, Saint Louis, MO 63110, USA
| | - Seana H Gaines
- Department of Radiology, Washington University School of Medicine, Saint Louis, MO 63110, USA
| | - Annie R Bice
- Department of Radiology, Washington University School of Medicine, Saint Louis, MO 63110, USA
| | - Michael J. Vasek
- Department of Genetics, Washington University School of Medicine, Saint Louis, MO 63110, USA
- Department of Psychiatry, Washington University School of Medicine, Saint Louis, MO 63110, USA
| | - Joel R. Garbow
- Department of Radiology, Washington University School of Medicine, Saint Louis, MO 63110, USA
- Intellectual and Development Developmental Disabilities Research Center, Washington University School of Medicine, Saint Louis, MO 63110, USA
| | - Joseph P. Culver
- Department of Radiology, Washington University School of Medicine, Saint Louis, MO 63110, USA
- Department of Physics, Washington University in St. Louis, Saint Louis, MO 63110, USA
- Department of Biomedical Engineering, Washington University in St. Louis, Saint Louis, MO 63110, USA
- Department of Neuroscience, Washington University School of Medicine, Saint Louis, MO 63110, USA
- Imaging Science PhD Program, Washington University in St. Louis, Saint Louis, MO 63110, USA
| | - Zila Martinez-Lozada
- Department of Pediatrics, The Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Martine Cohen-Salmon
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS, INSERM, Université PSL, Paris, France
| | - Joseph D. Dougherty
- Department of Genetics, Washington University School of Medicine, Saint Louis, MO 63110, USA
- Department of Psychiatry, Washington University School of Medicine, Saint Louis, MO 63110, USA
- Intellectual and Development Developmental Disabilities Research Center, Washington University School of Medicine, Saint Louis, MO 63110, USA
| | - Darshan Sapkota
- Department of Biological Sciences, University of Texas at Dallas, Richardson, Texas 75080, USA
- Department of Neuroscience, University of Texas at Dallas, Richardson, Texas 75080, USA
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10
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Bonosi L, Benigno UE, Musso S, Giardina K, Gerardi RM, Brunasso L, Costanzo R, Paolini F, Buscemi F, Avallone C, Gulino V, Iacopino DG, Maugeri R. The Role of Aquaporins in Epileptogenesis-A Systematic Review. Int J Mol Sci 2023; 24:11923. [PMID: 37569297 PMCID: PMC10418736 DOI: 10.3390/ijms241511923] [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: 05/25/2023] [Revised: 07/20/2023] [Accepted: 07/23/2023] [Indexed: 08/13/2023] Open
Abstract
Aquaporins (AQPs) are a family of membrane proteins involved in the transport of water and ions across cell membranes. AQPs have been shown to be implicated in various physiological and pathological processes in the brain, including water homeostasis, cell migration, and inflammation, among others. Epileptogenesis is a complex and multifactorial process that involves alterations in the structure and function of neuronal networks. Recent evidence suggests that AQPs may also play a role in the pathogenesis of epilepsy. In animal models of epilepsy, AQPs have been shown to be upregulated in regions of the brain that are involved in seizure generation, suggesting that they may contribute to the hyperexcitability of neuronal networks. Moreover, genetic studies have identified mutations in AQP genes associated with an increased risk of developing epilepsy. Our review aims to investigate the role of AQPs in epilepsy and seizure onset from a pathophysiological point of view, pointing out the potential molecular mechanism and their clinical implications.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | - Rosario Maugeri
- Neurosurgical Clinic, AOUP “Paolo Giaccone”, Post Graduate Residency Program in Neurologic Surgery, Department of Biomedicine Neurosciences and Advanced Diagnostics, School of Medicine, University of Palermo, 90127 Palermo, Italy; (L.B.); (U.E.B.); (S.M.); (K.G.); (R.M.G.); (L.B.); (R.C.); (F.P.); (F.B.); (C.A.); (V.G.); (D.G.I.)
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11
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Liu M, Huang J, Liu T, Yuan J, Lv C, Sha Z, Wu C, Jiang W, Liu X, Nie M, Chen Y, Dong S, Qian Y, Gao C, Fan Y, Wu D, Jiang R. Exogenous interleukin 33 enhances the brain's lymphatic drainage and toxic protein clearance in acute traumatic brain injury mice. Acta Neuropathol Commun 2023; 11:61. [PMID: 37024941 PMCID: PMC10080777 DOI: 10.1186/s40478-023-01555-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Accepted: 03/21/2023] [Indexed: 04/08/2023] Open
Abstract
The persistent dysregulation and accumulation of poisonous proteins from destructive neural tissues and cells activate pathological mechanisms after traumatic brain injury (TBI). The lymphatic drainage system of the brain, composed of the glymphatic system and meningeal lymphatic vessels (MLVs), plays an essential role in the clearance of toxic waste after brain injury. The neuroprotective effect of interleukin 33 (IL-33) in TBI mice has been demonstrated; however, its impact on brain lymphatic drainage is unclear. Here, we established a fluid percussion injury model to examine the IL-33 administration effects on neurological function and lymphatic drainage in the acute brain of TBI mice. We verified that exogenous IL-33 could improve the motor and memory skills of TBI mice and demonstrated that in the acute phase, it increased the exchange of cerebrospinal and interstitial fluid, reversed the dysregulation and depolarization of aquaporin-4 in the cortex and hippocampus, improved the drainage of MLVs to deep cervical lymph nodes, and reduced tau accumulation and glial activation. We speculate that the protective effect of exogenous IL-33 on TBI mice's motor and cognitive functions is related to the enhancement of brain lymphatic drainage and toxic metabolite clearance from the cortex and hippocampus in the acute stage. These data further support the notion that IL-33 therapy may be an effective treatment strategy for alleviating acute brain injury after TBI.
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Affiliation(s)
- Mingqi Liu
- Department of Neurosurgery, Tianjin Medical University General Hospital, 154 Anshan Road, Tianjin, 300052, China
- Tianjin Neurological Institute, Key Laboratory of Post Neuro-Injury Neuro-Repair and Regeneration in Central Nervous System, Ministry of Education and Tianjin City, Tianjin, 300052, China
| | - Jinhao Huang
- Department of Neurosurgery, Tianjin Medical University General Hospital, 154 Anshan Road, Tianjin, 300052, China.
- Tianjin Neurological Institute, Key Laboratory of Post Neuro-Injury Neuro-Repair and Regeneration in Central Nervous System, Ministry of Education and Tianjin City, Tianjin, 300052, China.
| | - Tao Liu
- Department of Neurosurgery, Tianjin Medical University General Hospital, 154 Anshan Road, Tianjin, 300052, China
- Tianjin Neurological Institute, Key Laboratory of Post Neuro-Injury Neuro-Repair and Regeneration in Central Nervous System, Ministry of Education and Tianjin City, Tianjin, 300052, China
| | - Jiangyuan Yuan
- Department of Neurosurgery, Tianjin Medical University General Hospital, 154 Anshan Road, Tianjin, 300052, China
- Tianjin Neurological Institute, Key Laboratory of Post Neuro-Injury Neuro-Repair and Regeneration in Central Nervous System, Ministry of Education and Tianjin City, Tianjin, 300052, China
| | - Chuanxiang Lv
- Department of Neurosurgery, The First Clinical Hospital, Jilin University, Changchun, China
| | - Zhuang Sha
- Department of Neurosurgery, Tianjin Medical University General Hospital, 154 Anshan Road, Tianjin, 300052, China
- Tianjin Neurological Institute, Key Laboratory of Post Neuro-Injury Neuro-Repair and Regeneration in Central Nervous System, Ministry of Education and Tianjin City, Tianjin, 300052, China
| | - Chenrui Wu
- Department of Neurosurgery, Tianjin Medical University General Hospital, 154 Anshan Road, Tianjin, 300052, China
- Tianjin Neurological Institute, Key Laboratory of Post Neuro-Injury Neuro-Repair and Regeneration in Central Nervous System, Ministry of Education and Tianjin City, Tianjin, 300052, China
| | - Weiwei Jiang
- Department of Neurosurgery, Tianjin Medical University General Hospital, 154 Anshan Road, Tianjin, 300052, China
- Tianjin Neurological Institute, Key Laboratory of Post Neuro-Injury Neuro-Repair and Regeneration in Central Nervous System, Ministry of Education and Tianjin City, Tianjin, 300052, China
| | - Xuanhui Liu
- Department of Neurosurgery, Tianjin Medical University General Hospital, 154 Anshan Road, Tianjin, 300052, China
- Tianjin Neurological Institute, Key Laboratory of Post Neuro-Injury Neuro-Repair and Regeneration in Central Nervous System, Ministry of Education and Tianjin City, Tianjin, 300052, China
| | - Meng Nie
- Department of Neurosurgery, Tianjin Medical University General Hospital, 154 Anshan Road, Tianjin, 300052, China
- Tianjin Neurological Institute, Key Laboratory of Post Neuro-Injury Neuro-Repair and Regeneration in Central Nervous System, Ministry of Education and Tianjin City, Tianjin, 300052, China
| | - Yupeng Chen
- Department of Neurosurgery, Tianjin Medical University General Hospital, 154 Anshan Road, Tianjin, 300052, China
- Tianjin Neurological Institute, Key Laboratory of Post Neuro-Injury Neuro-Repair and Regeneration in Central Nervous System, Ministry of Education and Tianjin City, Tianjin, 300052, China
| | - Shiying Dong
- Department of Neurosurgery, Tianjin Medical University General Hospital, 154 Anshan Road, Tianjin, 300052, China
- Tianjin Neurological Institute, Key Laboratory of Post Neuro-Injury Neuro-Repair and Regeneration in Central Nervous System, Ministry of Education and Tianjin City, Tianjin, 300052, China
| | - Yu Qian
- Department of Neurosurgery, Tianjin Medical University General Hospital, 154 Anshan Road, Tianjin, 300052, China
- Tianjin Neurological Institute, Key Laboratory of Post Neuro-Injury Neuro-Repair and Regeneration in Central Nervous System, Ministry of Education and Tianjin City, Tianjin, 300052, China
| | - Chuang Gao
- Department of Neurosurgery, Tianjin Medical University General Hospital, 154 Anshan Road, Tianjin, 300052, China
- Tianjin Neurological Institute, Key Laboratory of Post Neuro-Injury Neuro-Repair and Regeneration in Central Nervous System, Ministry of Education and Tianjin City, Tianjin, 300052, China
| | - Yibing Fan
- Department of Neurosurgery, Tianjin First Central Hospital, Tianjin, China
| | - Di Wu
- Department of Neurosurgery, Tianjin Medical University General Hospital, 154 Anshan Road, Tianjin, 300052, China
- Tianjin Neurological Institute, Key Laboratory of Post Neuro-Injury Neuro-Repair and Regeneration in Central Nervous System, Ministry of Education and Tianjin City, Tianjin, 300052, China
| | - Rongcai Jiang
- Department of Neurosurgery, Tianjin Medical University General Hospital, 154 Anshan Road, Tianjin, 300052, China.
- Tianjin Neurological Institute, Key Laboratory of Post Neuro-Injury Neuro-Repair and Regeneration in Central Nervous System, Ministry of Education and Tianjin City, Tianjin, 300052, China.
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12
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Zhang Y, Zhang C, He XZ, Li ZH, Meng JC, Mao RT, Li X, Xue R, Gui Q, Zhang GX, Wang LH. Interaction Between the Glymphatic System and α-Synuclein in Parkinson's Disease. Mol Neurobiol 2023; 60:2209-2222. [PMID: 36637746 DOI: 10.1007/s12035-023-03212-2] [Citation(s) in RCA: 23] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Accepted: 01/04/2023] [Indexed: 01/14/2023]
Abstract
The glymphatic system contributes to the clearance of amyloid-β from the brain and is disrupted in Alzheimer's disease. However, whether the system is involved in the removal of α-synuclein (α-syn) and whether it is suppressed in Parkinson's disease (PD) remain largely unknown. In mice receiving the intranigral injection of recombinant human α-syn, we found that the glymphatic suppression via aquaporin-4 (AQP4) gene deletion or acetazolamide treatment reduced the clearance of injected α-syn from the brain. In mice overexpressing the human A53T-α-syn, we revealed that AQP4 deficiency accelerated the accumulation of α-syn, facilitated the loss of dopaminergic neurons, and accelerated PD-like symptoms. We also found that the overexpression of A53T-α-syn reduced the expression/polarization of AQP4 and suppressed the glymphatic activity of mice. The study demonstrates a close interaction between the AQP4-mediated glymphatic system and parenchymal α-syn, indicating that restoring the glymphatic activity is a potential therapeutic target to delay PD progression.
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Affiliation(s)
- Yu Zhang
- Department of Physiology and Neurobiology, Suzhou Medical College of Soochow University, 199 Ren-Ai Road, Suzhou, 215123, People's Republic of China
| | - Cui Zhang
- Department of Physiology and Neurobiology, Suzhou Medical College of Soochow University, 199 Ren-Ai Road, Suzhou, 215123, People's Republic of China
| | - Xu-Zhong He
- Department of Physiology and Neurobiology, Suzhou Medical College of Soochow University, 199 Ren-Ai Road, Suzhou, 215123, People's Republic of China
| | - Zhen-Hua Li
- Department of Physiology and Neurobiology, Suzhou Medical College of Soochow University, 199 Ren-Ai Road, Suzhou, 215123, People's Republic of China
| | - Jing-Cai Meng
- Department of Physiology and Neurobiology, Suzhou Medical College of Soochow University, 199 Ren-Ai Road, Suzhou, 215123, People's Republic of China
| | - Rui-Ting Mao
- Department of Physiology and Neurobiology, Suzhou Medical College of Soochow University, 199 Ren-Ai Road, Suzhou, 215123, People's Republic of China
| | - Xin Li
- Department of Physiology and Neurobiology, Suzhou Medical College of Soochow University, 199 Ren-Ai Road, Suzhou, 215123, People's Republic of China
| | - Rong Xue
- Department of Physiology and Neurobiology, Suzhou Medical College of Soochow University, 199 Ren-Ai Road, Suzhou, 215123, People's Republic of China
| | - Qian Gui
- Department of Neurology, Suzhou Municipal Hospital, 26 Dao-Qian Street, Suzhou, 215002, People's Republic of China
| | - Guo-Xing Zhang
- Department of Physiology and Neurobiology, Suzhou Medical College of Soochow University, 199 Ren-Ai Road, Suzhou, 215123, People's Republic of China
| | - Lin-Hui Wang
- Department of Physiology and Neurobiology, Suzhou Medical College of Soochow University, 199 Ren-Ai Road, Suzhou, 215123, People's Republic of China.
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13
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Sepehrinezhad A, Stolze Larsen F, Ashayeri Ahmadabad R, Shahbazi A, Sahab Negah S. The Glymphatic System May Play a Vital Role in the Pathogenesis of Hepatic Encephalopathy: A Narrative Review. Cells 2023; 12:cells12070979. [PMID: 37048052 PMCID: PMC10093707 DOI: 10.3390/cells12070979] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Revised: 02/20/2023] [Accepted: 03/21/2023] [Indexed: 04/14/2023] Open
Abstract
Hepatic encephalopathy (HE) is a neurological complication of liver disease resulting in cognitive, psychiatric, and motor symptoms. Although hyperammonemia is a key factor in the pathogenesis of HE, several other factors have recently been discovered. Among these, the impairment of a highly organized perivascular network known as the glymphatic pathway seems to be involved in the progression of some neurological complications due to the accumulation of misfolded proteins and waste substances in the brain interstitial fluids (ISF). The glymphatic system plays an important role in the clearance of brain metabolic derivatives and prevents aggregation of neurotoxic agents in the brain ISF. Impairment of it will result in aggravated accumulation of neurotoxic agents in the brain ISF. This could also be the case in patients with liver failure complicated by HE. Indeed, accumulation of some metabolic by-products and agents such as ammonia, glutamine, glutamate, and aromatic amino acids has been reported in the human brain ISF using microdialysis technique is attributed to worsening of HE and correlates with brain edema. Furthermore, it has been reported that the glymphatic system is impaired in the olfactory bulb, prefrontal cortex, and hippocampus in an experimental model of HE. In this review, we discuss different factors that may affect the function of the glymphatic pathways and how these changes may be involved in HE.
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Affiliation(s)
- Ali Sepehrinezhad
- Department of Neuroscience, Faculty of Advanced Technologies in Medicine, Iran University of Medical Sciences, Tehran 1449614535, Iran
- Neuroscience Research Center, Mashhad University of Medical Sciences, Mashhad 9919191778, Iran
| | - Fin Stolze Larsen
- Department of Gastroenterology and Hepatology, Rigshospitalet, Copenhagen University Hospital, 999017 Copenhagen, Denmark
| | | | - Ali Shahbazi
- Department of Neuroscience, Faculty of Advanced Technologies in Medicine, Iran University of Medical Sciences, Tehran 1449614535, Iran
- Cellular and Molecular Research Center, Iran University of Medical Sciences, Tehran 1449614535, Iran
| | - Sajad Sahab Negah
- Neuroscience Research Center, Mashhad University of Medical Sciences, Mashhad 9919191778, Iran
- Shefa Neuroscience Research Center, Khatam Alanbia Hospital, Tehran 1449614535, Iran
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14
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Chierzi S, Kacerovsky JB, Fok AHK, Lahaie S, Shibi Rosen A, Farmer WT, Murai KK. Astrocytes Transplanted during Early Postnatal Development Integrate, Mature, and Survive Long Term in Mouse Cortex. J Neurosci 2023; 43:1509-1529. [PMID: 36669885 PMCID: PMC10008063 DOI: 10.1523/jneurosci.0544-22.2023] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Revised: 12/15/2022] [Accepted: 01/06/2023] [Indexed: 01/21/2023] Open
Abstract
Astrocytes have complex structural, molecular, and physiological properties and form specialized microenvironments that support circuit-specific functions in the CNS. To better understand how astrocytes acquire their unique features, we transplanted immature mouse cortical astrocytes into the developing cortex of male and female mice and assessed their integration, maturation, and survival. Within days, transplanted astrocytes developed morphologies and acquired territories and tiling behavior typical of cortical astrocytes. At 35-47 d post-transplantation, astrocytes appeared morphologically mature and expressed levels of EAAT2/GLT1 similar to nontransplanted astrocytes. Transplanted astrocytes also supported excitatory/inhibitory (E/I) presynaptic terminals within their territories, and displayed normal Ca2+ events. Transplanted astrocytes showed initially reduced expression of aquaporin 4 (AQP4) at endfeet and elevated expression of EAAT1/GLAST, with both proteins showing normalized expression by 110 d and one year post-transplantation, respectively. To understand how specific brain regions support astrocytic integration and maturation, we transplanted cortical astrocytes into the developing cerebellum. Cortical astrocytes interlaced with Bergmann glia (BG) in the cerebellar molecular layer to establish discrete territories. However, transplanted astrocytes retained many cortical astrocytic features including higher levels of EAAT2/GLT1, lower levels of EAAT1/GLAST, and the absence of expression of the AMPAR subunit GluA1. Collectively, our findings demonstrate that immature cortical astrocytes integrate, mature, and survive (more than one year) following transplantation and retain cortical astrocytic properties. Astrocytic transplantation can be useful for investigating cell-autonomous (intrinsic) and non-cell-autonomous (environmental) mechanisms contributing to astrocytic development/diversity, and for determining the optimal timing for transplanting astrocytes for cellular delivery or replacement in regenerative medicine.SIGNIFICANCE STATEMENT The mechanisms that enable astrocytes to acquire diverse molecular and structural properties remain to be better understood. In this study, we systematically analyzed the properties of cortical astrocytes following their transplantation to the early postnatal brain. We found that immature cortical astrocytes transplanted into cerebral cortex during early postnatal mouse development integrate and establish normal astrocytic properties, and show long-term survival in vivo (more than one year). In contrast, transplanted cortical astrocytes display reduced or altered ability to integrate into the more mature cerebral cortex or developing cerebellum, respectively. This study demonstrates the developmental potential of transplanted cortical astrocytes and provides an approach to tease apart cell-autonomous (intrinsic) and non-cell-autonomous (environmental) mechanisms that determine the structural, molecular, and physiological phenotype of astrocytes.
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Affiliation(s)
- Sabrina Chierzi
- Centre for Research in Neuroscience, Department of Neurology and Neurosurgery, Brain Repair and Integrative Neuroscience Program, Research Institute of the McGill University Health Centre, Montreal General Hospital, Montreal, Quebec H3G 1A4, Canada
| | - J Benjamin Kacerovsky
- Centre for Research in Neuroscience, Department of Neurology and Neurosurgery, Brain Repair and Integrative Neuroscience Program, Research Institute of the McGill University Health Centre, Montreal General Hospital, Montreal, Quebec H3G 1A4, Canada
| | - Albert H K Fok
- Centre for Research in Neuroscience, Department of Neurology and Neurosurgery, Brain Repair and Integrative Neuroscience Program, Research Institute of the McGill University Health Centre, Montreal General Hospital, Montreal, Quebec H3G 1A4, Canada
| | - Sylvie Lahaie
- Centre for Research in Neuroscience, Department of Neurology and Neurosurgery, Brain Repair and Integrative Neuroscience Program, Research Institute of the McGill University Health Centre, Montreal General Hospital, Montreal, Quebec H3G 1A4, Canada
| | - Arielle Shibi Rosen
- Centre for Research in Neuroscience, Department of Neurology and Neurosurgery, Brain Repair and Integrative Neuroscience Program, Research Institute of the McGill University Health Centre, Montreal General Hospital, Montreal, Quebec H3G 1A4, Canada
| | - W Todd Farmer
- Centre for Research in Neuroscience, Department of Neurology and Neurosurgery, Brain Repair and Integrative Neuroscience Program, Research Institute of the McGill University Health Centre, Montreal General Hospital, Montreal, Quebec H3G 1A4, Canada
| | - Keith K Murai
- Centre for Research in Neuroscience, Department of Neurology and Neurosurgery, Brain Repair and Integrative Neuroscience Program, Research Institute of the McGill University Health Centre, Montreal General Hospital, Montreal, Quebec H3G 1A4, Canada
- Quantitative Life Sciences Graduate Program, McGill University, Montreal, Quebec H3A 2A7, Canada
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15
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Soden PA, Henderson AR, Lee E. A Microfluidic Model of AQP4 Polarization Dynamics and Fluid Transport in the Healthy and Inflamed Human Brain: The First Step Towards Glymphatics-on-a-Chip. Adv Biol (Weinh) 2022; 6:e2200027. [PMID: 35922370 PMCID: PMC9771879 DOI: 10.1002/adbi.202200027] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Revised: 07/01/2022] [Indexed: 01/28/2023]
Abstract
Dysfunction of the aquaporin-4 (AQP4)-dependent glymphatic waste clearance pathway has recently been implicated in the pathogenesis of several neurodegenerative diseases. However, it is difficult to unravel the causative relationship between glymphatic dysfunction, AQP4 depolarization, protein aggregation, and inflammation in neurodegeneration using animal models alone. There is currently a clear, unmet need for in vitro models of the brain's waterscape, and the first steps towards a bona fide "glymphatics-on-a-chip" are taken in the present study. It is demonstrated that chronic exposure to lipopolysaccharide (LPS), amyloid-β(1-42) oligomers, and an AQP4 inhibitor impairs the drainage of fluid and amyloid-β(1-40) tracer in a gliovascular unit (GVU)-on-a-chip model containing human astrocytes and brain microvascular endothelial cells. The LPS-induced drainage impairment is partially retained following cell lysis, indicating that neuroinflammation induces parallel changes in cell-dependent and matrisome-dependent fluid transport pathways in GVU-on-a-chip. Additionally, AQP4 depolarization is observed following LPS treatment, suggesting that LPS-induced drainage impairments on-chip may be driven in part by changes in AQP4-dependent fluid dynamics.
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Affiliation(s)
- Paul A Soden
- College of Human Ecology, Cornell University, Ithaca, NY, 14853, USA
| | - Aria R Henderson
- Nancy E. and Peter C. Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY, 14853, USA
| | - Esak Lee
- Nancy E. and Peter C. Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY, 14853, USA
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16
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Zhao Z, He J, Chen Y, Wang Y, Wang C, Tan C, Liao J, Xiao G. The pathogenesis of idiopathic normal pressure hydrocephalus based on the understanding of AQP1 and AQP4. Front Mol Neurosci 2022; 15:952036. [PMID: 36204139 PMCID: PMC9530743 DOI: 10.3389/fnmol.2022.952036] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Accepted: 08/12/2022] [Indexed: 11/21/2022] Open
Abstract
Idiopathic normal pressure hydrocephalus (iNPH) is a neurological disorder without a recognized cause. Aquaporins (AQPs) are transmembrane channels that carry water through cell membranes and are critical for cerebrospinal fluid circulation and cerebral water balance. The function of AQPs in developing and maintaining hydrocephalus should be studied in greater detail as a possible diagnostic and therapeutic tool. Recent research indicates that patients with iNPH exhibited high levels of aquaporin 1 and low levels of aquaporin 4 expression, suggesting that these AQPs are essential in iNPH pathogenesis. To determine the source of iNPH and diagnose and treat it, it is necessary to examine and appreciate their function in the genesis and maintenance of hydrocephalus. The expression, function, and regulation of AQPs in iNPH are reviewed in this article, in order to provide fresh targets and suggestions for future research.
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Affiliation(s)
- Zitong Zhao
- Department of Neurosurgery, Xiangya Hospital, Central South University, Changsha, China
- Diagnosis and Treatment Center for Hydrocephalus, Xiangya Hospital, Central South University, Changsha, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
| | - Jian He
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China
| | - Yibing Chen
- Department of Neurosurgery, Xiangya Hospital, Central South University, Changsha, China
- Diagnosis and Treatment Center for Hydrocephalus, Xiangya Hospital, Central South University, Changsha, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
| | - Yuchang Wang
- Department of Neurosurgery, Xiangya Hospital, Central South University, Changsha, China
- Diagnosis and Treatment Center for Hydrocephalus, Xiangya Hospital, Central South University, Changsha, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
| | - Chuansen Wang
- Department of Neurosurgery, Xiangya Hospital, Central South University, Changsha, China
- Diagnosis and Treatment Center for Hydrocephalus, Xiangya Hospital, Central South University, Changsha, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
| | - Changwu Tan
- Department of Neurosurgery, Xiangya Hospital, Central South University, Changsha, China
- Diagnosis and Treatment Center for Hydrocephalus, Xiangya Hospital, Central South University, Changsha, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
| | - Junbo Liao
- Department of Neurosurgery, Xiangya Hospital, Central South University, Changsha, China
- Diagnosis and Treatment Center for Hydrocephalus, Xiangya Hospital, Central South University, Changsha, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
| | - Gelei Xiao
- Department of Neurosurgery, Xiangya Hospital, Central South University, Changsha, China
- Diagnosis and Treatment Center for Hydrocephalus, Xiangya Hospital, Central South University, Changsha, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
- *Correspondence: Gelei Xiao
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17
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Sulforaphane Upregulates Cultured Mouse Astrocytic Aquaporin-4 Expression through p38 MAPK Pathway. JOURNAL OF HEALTHCARE ENGINEERING 2022; 2022:1144124. [PMID: 35991296 PMCID: PMC9385362 DOI: 10.1155/2022/1144124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Revised: 12/31/2021] [Accepted: 06/22/2022] [Indexed: 11/18/2022]
Abstract
Protein misfolding and/or aggregation are common pathological features associated with a number of neurodegenerative diseases, including Alzheimer's disease (AD) and Parkinson disease (PD). Abnormal protein aggregation may be caused by misfolding of the protein and/or dysfunction of the protein clearance system. Recent studies have demonstrated that the specific water channel protein, aquaporin-4 (AQP4), plays a role in the pathogenesis of neurodegenerative diseases involving protein clearance system. In this study, we aimed to investigate the role of sulforaphane (SFN) in the upregulation of AQP4 expression, along with its underlying mechanism using cultured mouse astrocytes as a model system. At low concentrations, SFN was found to increase cell proliferation and result in the activation of astrocytes. However, high SFN concentrations were found to suppress cell proliferation of astrocytes. In addition, our study found that a 1 μM concentration of SFN resulted in the upregulation of AQP4 expression and p38 MAPK phosphorylation in cultured mouse astrocytes. Moreover, we demonstrated that the upregulation of AQP4 expression was significantly attenuated when cells were pretreated with SB203580, a p38 MAPK inhibitor. In conclusion, our findings from this study revealed that SFN exerts hormesis effect on cultured mouse astrocytes and can upregulate astrocytic AQP4 expression by targeting the p38 MAPK pathway.
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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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19
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Yan L, Moriarty RA, Stroka KM. Recent progress and new challenges in modeling of human pluripotent stem cell-derived blood-brain barrier. Theranostics 2021; 11:10148-10170. [PMID: 34815809 PMCID: PMC8581424 DOI: 10.7150/thno.63195] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Accepted: 10/05/2021] [Indexed: 12/13/2022] Open
Abstract
The blood-brain barrier (BBB) is a semipermeable unit that serves to vascularize the central nervous system (CNS) while tightly regulating the movement of molecules, ions, and cells between the blood and the brain. The BBB precisely controls brain homeostasis and protects the neural tissue from toxins and pathogens. The BBB is coordinated by a tight monolayer of brain microvascular endothelial cells, which is subsequently supported by mural cells, astrocytes, and surrounding neuronal cells that regulate the barrier function with a series of specialized properties. Dysfunction of barrier properties is an important pathological feature in the progression of various neurological diseases. In vitro BBB models recapitulating the physiological and diseased states are important tools to understand the pathological mechanism and to serve as a platform to screen potential drugs. Recent advances in this field have stemmed from the use of pluripotent stem cells (PSCs). Various cell types of the BBB such as brain microvascular endothelial cells (BMECs), pericytes, and astrocytes have been derived from PSCs and synergistically incorporated to model the complex BBB structure in vitro. In this review, we summarize the most recent protocols and techniques for the differentiation of major cell types of the BBB. We also discuss the progress of BBB modeling by using PSC-derived cells and perspectives on how to reproduce more natural BBBs in vitro.
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Affiliation(s)
- Li Yan
- Fischell Department of Bioengineering, University of Maryland, College Park, MD 20742, USA
| | - Rebecca A. Moriarty
- Fischell Department of Bioengineering, University of Maryland, College Park, MD 20742, USA
| | - Kimberly M. Stroka
- Fischell Department of Bioengineering, University of Maryland, College Park, MD 20742, USA
- Biophysics Program, University of Maryland, College Park, MD 20742, USA
- Center for Stem Cell Biology and Regenerative Medicine, University of Maryland, Baltimore, MD 21201, USA
- Marlene and Stewart Greenebaum Comprehensive Cancer Center, University of Maryland, Baltimore, MD 21201, USA
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20
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Hart CG, Karimi-Abdolrezaee S. Recent insights on astrocyte mechanisms in CNS homeostasis, pathology, and repair. J Neurosci Res 2021; 99:2427-2462. [PMID: 34259342 DOI: 10.1002/jnr.24922] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2021] [Revised: 06/06/2021] [Accepted: 06/24/2021] [Indexed: 12/20/2022]
Abstract
Astrocytes play essential roles in development, homeostasis, injury, and repair of the central nervous system (CNS). Their development is tightly regulated by distinct spatial and temporal cues during embryogenesis and into adulthood throughout the CNS. Astrocytes have several important responsibilities such as regulating blood flow and permeability of the blood-CNS barrier, glucose metabolism and storage, synapse formation and function, and axon myelination. In CNS pathologies, astrocytes also play critical parts in both injury and repair mechanisms. Upon injury, they undergo a robust phenotypic shift known as "reactive astrogliosis," which results in both constructive and deleterious outcomes. Astrocyte activation and migration at the site of injury provides an early defense mechanism to minimize the extent of injury by enveloping the lesion area. However, astrogliosis also contributes to the inhibitory microenvironment of CNS injury and potentiate secondary injury mechanisms, such as inflammation, oxidative stress, and glutamate excitotoxicity, which facilitate neurodegeneration in CNS pathologies. Intriguingly, reactive astrocytes are increasingly a focus in current therapeutic strategies as their activation can be modulated toward a neuroprotective and reparative phenotype. This review will discuss recent advancements in knowledge regarding the development and role of astrocytes in the healthy and pathological CNS. We will also review how astrocytes have been genetically modified to optimize their reparative potential after injury, and how they may be transdifferentiated into neurons and oligodendrocytes to promote repair after CNS injury and neurodegeneration.
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Affiliation(s)
- Christopher G Hart
- Department of Physiology and Pathophysiology, Spinal Cord Research Centre, Children's Hospital Research Institute of Manitoba, University of Manitoba, Winnipeg, MB, Canada
| | - Soheila Karimi-Abdolrezaee
- Department of Physiology and Pathophysiology, Spinal Cord Research Centre, Children's Hospital Research Institute of Manitoba, University of Manitoba, Winnipeg, MB, Canada
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21
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Price BR, Johnson LA, Norris CM. Reactive astrocytes: The nexus of pathological and clinical hallmarks of Alzheimer's disease. Ageing Res Rev 2021; 68:101335. [PMID: 33812051 PMCID: PMC8168445 DOI: 10.1016/j.arr.2021.101335] [Citation(s) in RCA: 62] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Revised: 01/21/2021] [Accepted: 03/20/2021] [Indexed: 02/06/2023]
Abstract
Astrocyte reactivity is a hallmark of neuroinflammation that arises with Alzheimer’s disease (AD) and nearly every other neurodegenerative condition. While astrocytes certainly contribute to classic inflammatory processes (e.g. cytokine release, waste clearance, and tissue repair), newly emerging technologies for measuring and targeting cell specific activities in the brain have uncovered essential roles for astrocytes in synapse function, brain metabolism, neurovascular coupling, and sleep/wake patterns. In this review, we use a holistic approach to incorporate, and expand upon, classic neuroinflammatory concepts to consider how astrocyte dysfunction/reactivity modulates multiple pathological and clinical hallmarks of AD. Our ever-evolving understanding of astrocyte signaling in neurodegeneration is not only revealing new drug targets and treatments for dementia but is suggesting we reimagine AD pathophysiological mechanisms.
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Affiliation(s)
- Brittani R Price
- Department of Neuroscience, Tufts University School of Medicine, 136 Harrison Ave., Boston, MA, 02111, USA
| | - Lance A Johnson
- Sanders-Brown Center on Aging, University of Kentucky, 800 S. Limestone St., Lexington, KY, 40356, USA; Department of Physiology, University of Kentucky, College of Medicine, UK Medical Center MN 150, Lexington, KY, 40536, USA
| | - Christopher M Norris
- Sanders-Brown Center on Aging, University of Kentucky, 800 S. Limestone St., Lexington, KY, 40356, USA; Department of Pharmacology and Nutritional Sciences, University of Kentucky, College of Medicine, UK Medical Center MN 150, Lexington, KY, 40536, USA.
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22
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Cohen-Salmon M, Slaoui L, Mazaré N, Gilbert A, Oudart M, Alvear-Perez R, Elorza-Vidal X, Chever O, Boulay AC. Astrocytes in the regulation of cerebrovascular functions. Glia 2020; 69:817-841. [PMID: 33058289 DOI: 10.1002/glia.23924] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 09/18/2020] [Accepted: 09/21/2020] [Indexed: 12/18/2022]
Abstract
Astrocytes are the most numerous type of neuroglia in the brain and have a predominant influence on the cerebrovascular system; they control perivascular homeostasis, the integrity of the blood-brain barrier, the dialogue with the peripheral immune system, the transfer of metabolites from the blood, and blood vessel contractility in response to neuronal activity. These regulatory processes occur in a specialized interface composed of perivascular astrocyte extensions that almost completely cover the cerebral blood vessels. Scientists have only recently started to study how this interface is formed and how it influences cerebrovascular functions. Here, we review the literature on the astrocytes' role in the regulation of the cerebrovascular system. We cover the anatomy and development of the gliovascular interface, the known gliovascular functions, and molecular factors, the latter's implication in certain pathophysiological situations, and recent cutting-edge experimental tools developed to examine the astrocytes' role at the vascular interface. Finally, we highlight some open questions in this field of research.
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Affiliation(s)
- Martine Cohen-Salmon
- Physiology and Physiopathology of the Gliovascular Unit Research Group, Center for Interdisciplinary Research in Biology (CIRB), College de France, CNRS Unité Mixte de Recherche 724, INSERM Unité 1050, Labex Memolife, PSL Research University, Paris, France
| | - Leila Slaoui
- Physiology and Physiopathology of the Gliovascular Unit Research Group, Center for Interdisciplinary Research in Biology (CIRB), College de France, CNRS Unité Mixte de Recherche 724, INSERM Unité 1050, Labex Memolife, PSL Research University, Paris, France
| | - Noémie Mazaré
- Physiology and Physiopathology of the Gliovascular Unit Research Group, Center for Interdisciplinary Research in Biology (CIRB), College de France, CNRS Unité Mixte de Recherche 724, INSERM Unité 1050, Labex Memolife, PSL Research University, Paris, France
| | - Alice Gilbert
- Physiology and Physiopathology of the Gliovascular Unit Research Group, Center for Interdisciplinary Research in Biology (CIRB), College de France, CNRS Unité Mixte de Recherche 724, INSERM Unité 1050, Labex Memolife, PSL Research University, Paris, France
| | - Marc Oudart
- Physiology and Physiopathology of the Gliovascular Unit Research Group, Center for Interdisciplinary Research in Biology (CIRB), College de France, CNRS Unité Mixte de Recherche 724, INSERM Unité 1050, Labex Memolife, PSL Research University, Paris, France
| | - Rodrigo Alvear-Perez
- Physiology and Physiopathology of the Gliovascular Unit Research Group, Center for Interdisciplinary Research in Biology (CIRB), College de France, CNRS Unité Mixte de Recherche 724, INSERM Unité 1050, Labex Memolife, PSL Research University, Paris, France
| | - Xabier Elorza-Vidal
- Physiology and Physiopathology of the Gliovascular Unit Research Group, Center for Interdisciplinary Research in Biology (CIRB), College de France, CNRS Unité Mixte de Recherche 724, INSERM Unité 1050, Labex Memolife, PSL Research University, Paris, France
| | - Oana Chever
- Normandie University, UNIROUEN, INSERM, DC2N, IRIB, Rouen, France
| | - Anne-Cécile Boulay
- Physiology and Physiopathology of the Gliovascular Unit Research Group, Center for Interdisciplinary Research in Biology (CIRB), College de France, CNRS Unité Mixte de Recherche 724, INSERM Unité 1050, Labex Memolife, PSL Research University, Paris, France
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23
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Harrison IF, Ismail O, Machhada A, Colgan N, Ohene Y, Nahavandi P, Ahmed Z, Fisher A, Meftah S, Murray TK, Ottersen OP, Nagelhus EA, O’Neill MJ, Wells JA, Lythgoe MF. Impaired glymphatic function and clearance of tau in an Alzheimer's disease model. Brain 2020; 143:2576-2593. [PMID: 32705145 PMCID: PMC7447521 DOI: 10.1093/brain/awaa179] [Citation(s) in RCA: 216] [Impact Index Per Article: 54.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Revised: 03/28/2020] [Accepted: 04/13/2020] [Indexed: 01/09/2023] Open
Abstract
The glymphatic system, that is aquaporin 4 (AQP4) facilitated exchange of CSF with interstitial fluid (ISF), may provide a clearance pathway for protein species such as amyloid-β and tau, which accumulate in the brain in Alzheimer's disease. Further, tau protein transference via the extracellular space, the compartment that is cleared by the glymphatic pathway, allows for its neuron-to-neuron propagation, and the regional progression of tauopathy in the disorder. The glymphatic system therefore represents an exciting new target for Alzheimer's disease. Here we aim to understand the involvement of glymphatic CSF-ISF exchange in tau pathology. First, we demonstrate impaired CSF-ISF exchange and AQP4 polarization in a mouse model of tauopathy, suggesting that this clearance pathway may have the potential to exacerbate or even induce pathogenic accumulation of tau. Subsequently, we establish the central role of AQP4 in the glymphatic clearance of tau from the brain; showing marked impaired glymphatic CSF-ISF exchange and tau protein clearance using the novel AQP4 inhibitor, TGN-020. As such, we show that this system presents as a novel druggable target for the treatment of Alzheimer's disease, and possibly other neurodegenerative diseases alike.
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Affiliation(s)
- Ian F Harrison
- UCL Centre for Advanced Biomedical Imaging, Department of Imaging, Division of Medicine, University College London, London, UK
| | - Ozama Ismail
- UCL Centre for Advanced Biomedical Imaging, Department of Imaging, Division of Medicine, University College London, London, UK
| | - Asif Machhada
- UCL Centre for Advanced Biomedical Imaging, Department of Imaging, Division of Medicine, University College London, London, UK
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, UK
| | - Niall Colgan
- UCL Centre for Advanced Biomedical Imaging, Department of Imaging, Division of Medicine, University College London, London, UK
- School of Physics, National University of Ireland Galway, Ireland
| | - Yolanda Ohene
- UCL Centre for Advanced Biomedical Imaging, Department of Imaging, Division of Medicine, University College London, London, UK
| | - Payam Nahavandi
- UCL Centre for Advanced Biomedical Imaging, Department of Imaging, Division of Medicine, University College London, London, UK
| | - Zeshan Ahmed
- Eli Lilly and Company, Erl Wood Manor, Windlesham, Surrey, UK
| | - Alice Fisher
- Eli Lilly and Company, Erl Wood Manor, Windlesham, Surrey, UK
| | - Soraya Meftah
- Eli Lilly and Company, Erl Wood Manor, Windlesham, Surrey, UK
| | - Tracey K Murray
- Eli Lilly and Company, Erl Wood Manor, Windlesham, Surrey, UK
| | - Ole P Ottersen
- Office of the President, Karolinska Institutet, Stockholm, Sweden
| | - Erlend A Nagelhus
- Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | | | - Jack A Wells
- UCL Centre for Advanced Biomedical Imaging, Department of Imaging, Division of Medicine, University College London, London, UK
| | - Mark F Lythgoe
- UCL Centre for Advanced Biomedical Imaging, Department of Imaging, Division of Medicine, University College London, London, UK
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24
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Martinez-Lozada Z, Robinson MB. Reciprocal communication between astrocytes and endothelial cells is required for astrocytic glutamate transporter 1 (GLT-1) expression. Neurochem Int 2020; 139:104787. [PMID: 32650029 DOI: 10.1016/j.neuint.2020.104787] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Revised: 05/15/2020] [Accepted: 06/14/2020] [Indexed: 12/12/2022]
Abstract
Astrocytes have diverse functions that are supported by their anatomic localization between neurons and blood vessels. One of these functions is the clearance of extracellular glutamate. Astrocytes clear glutamate using two Na+-dependent glutamate transporters, GLT-1 (also called EAAT2) and GLAST (also called EAAT1). GLT-1 expression increases during synaptogenesis and is a marker of astrocyte maturation. Over 20 years ago, several groups demonstrated that astrocytes in culture express little or no GLT-1 and that neurons induce expression. We recently demonstrated that co-culturing endothelia with mouse astrocytes also induced expression of GLT-1 and GLAST. These increases were blocked by an inhibitor of γ-secretase. This and other observations are consistent with the hypothesis that Notch signaling is required, but the ligands involved were not identified. In the present study, we used rat astrocyte cultures to further define the mechanisms by which endothelia induce expression of GLT-1 and GLAST. We found that co-cultures of astrocytes and endothelia express higher levels of GLT-1 and GLAST protein and mRNA. That endothelia activate Hes5, a transcription factor target of Notch, in astrocytes. Using recombinant Notch ligands, anti-Notch ligand neutralizing antibodies, and shRNAs, we provide evidence that both Dll1 and Dll4 contribute to endothelia-dependent regulation of GLT-1. We also provide evidence that astrocytes secrete a factor(s) that induces expression of Dll4 in endothelia and that this effect is required for Notch-dependent induction of GLT-1. Together these studies indicate that reciprocal communication between astrocytes and endothelia is required for appropriate astrocyte maturation and that endothelia likely deploy additional non-Notch signals to induce GLT-1.
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Affiliation(s)
- Zila Martinez-Lozada
- Departments of Pediatrics, Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, PA, USA, 19104-4318
| | - Michael B Robinson
- Departments of Pediatrics, Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, PA, USA, 19104-4318; Systems Pharmacology and Translational Therapeutics, Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, PA, 19104-4318, USA.
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25
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Paraiso HC, Wang X, Kuo PC, Furnas D, Scofield BA, Chang FL, Yen JH, Yu IC. Isolation of Mouse Cerebral Microvasculature for Molecular and Single-Cell Analysis. Front Cell Neurosci 2020; 14:84. [PMID: 32327974 PMCID: PMC7160798 DOI: 10.3389/fncel.2020.00084] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Accepted: 03/20/2020] [Indexed: 12/11/2022] Open
Abstract
Brain microvasculature forms a specialized structure, the blood-brain barrier (BBB), to maintain homeostasis and integrity of the central nervous system (CNS). The BBB dysfunction is emerging as a critical contributor to multiple neurological disorders, including stroke, traumatic brain injury, autoimmune multiple sclerosis, and neurodegenerative diseases. The brain microvasculature exhibits highly cellular and regional heterogeneity to accommodate dynamic changes of microenvironment during homeostasis and diseases. Thus, investigating the underlying mechanisms that contribute to molecular or cellular changes of the BBB is a significant challenge. Here, we describe an optimized protocol to purify microvessels from the mouse cerebral cortex using mechanical homogenization and density-gradient centrifugation, while maintaining the structural integrity and functional activity of the BBB. We show that the isolated microvessel fragments consist of BBB cell populations, including endothelial cells, astrocyte end-feet, pericytes, as well as tight junction proteins that seal endothelial cells. Furthermore, we describe the procedures to generate single-cell suspensions from isolated microvessel fragments. We demonstrate that cells in the single-cell suspensions are highly viable and suitable for single-cell RNA-sequencing analysis. This protocol does not require transgenic mice and cell sorting equipment to isolate fluorescence-labeled endothelial cells. The optimized procedures can be applied to different disease models to generate viable cells for single-cell analysis to uncover transcriptional or epigenetic landscapes of BBB component cells.
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Affiliation(s)
- Hallel C Paraiso
- Department of Anatomy, Cell Biology, and Physiology, Indiana University School of Medicine, Fort Wayne, IN, United States
| | - Xueqian Wang
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, Fort Wayne, IN, United States
| | - Ping-Chang Kuo
- Department of Microbiology and Immunology, Indiana University School of Medicine, Fort Wayne, IN, United States
| | - Destin Furnas
- Department of Microbiology and Immunology, Indiana University School of Medicine, Fort Wayne, IN, United States
| | - Barbara A Scofield
- Department of Microbiology and Immunology, Indiana University School of Medicine, Fort Wayne, IN, United States
| | - Fen-Lei Chang
- Department of Neurology, Indiana University School of Medicine, Fort Wayne, IN, United States
| | - Jui-Hung Yen
- Department of Microbiology and Immunology, Indiana University School of Medicine, Fort Wayne, IN, United States
| | - I-Chen Yu
- Department of Anatomy, Cell Biology, and Physiology, Indiana University School of Medicine, Fort Wayne, IN, United States
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26
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Hoddevik EH, Rao SB, Zahl S, Boldt HB, Ottersen OP, Amiry-Moghaddam M. Organisation of extracellular matrix proteins laminin and agrin in pericapillary basal laminae in mouse brain. Brain Struct Funct 2020; 225:805-816. [PMID: 32072250 PMCID: PMC7046580 DOI: 10.1007/s00429-020-02036-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2019] [Accepted: 01/29/2020] [Indexed: 01/08/2023]
Abstract
Evidence suggests that extracellular matrix molecules of perivascular basal laminae help orchestrate the molecular assemblies at the gliovascular interface. Specifically, laminin and agrin are thought to tether the dystrophin-associated protein (DAP) complex to the astrocytic basal lamina. This complex includes α-syntrophin (α-Syn), which is believed to anchor aquaporin-4 (AQP4) to astrocytic endfoot membrane domains. We have previously shown that the size of the perivascular AQP4 pool differs considerably between brain regions in an α-Syn-dependent manner. Also, both AQP4 and α-Syn occur at higher densities in endfoot membrane domains facing pericytes than in endfoot membrane domains facing endothelial cells. The heterogeneous distribution of AQP4 at the regional and capillary level has been attributed to a direct interaction between AQP4 and α-Syn. This would be challenged (1) if the microdistributions of laminin and agrin fail to align with those of DAP and AQP4 and (2) if targeted deletion of α-Syn leads to a loss of laminin and/or agrin. Here, we provide the first detailed and quantitative analysis of laminin and agrin in brain basal laminae of mice. We show that the microdistributions of these molecules vary in a fashion that is well aligned with the previously reported microdistribution of AQP4. We also demonstrate that the expression patterns of laminin and agrin are insensitive to targeted deletion of α-Syn, suggesting that α-Syn deletion affects AQP4 directly and not indirectly via laminin or agrin. These data fill remaining voids in the current model of how key molecules are assembled and tethered at the gliovascular interface.
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Affiliation(s)
- Eystein Hellstrøm Hoddevik
- Division of Anatomy, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Blindern, Post box 1105, 0317, Oslo, Norway
- Department of Pathology, Oslo University Hospital, Oslo, Norway
| | - Shreyas Balachandra Rao
- Division of Anatomy, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Blindern, Post box 1105, 0317, Oslo, Norway
| | - Soulmaz Zahl
- Division of Anatomy, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Blindern, Post box 1105, 0317, Oslo, Norway
| | - Henning Bünsow Boldt
- Division of Anatomy, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Blindern, Post box 1105, 0317, Oslo, Norway
- Department of Pathology, Odense University Hospital, Odense, Denmark
| | - Ole Petter Ottersen
- Division of Anatomy, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Blindern, Post box 1105, 0317, Oslo, Norway
- President's Office, Karolinska Institutet, Nobels väg 6, 171 77, Stockholm, Sweden
| | - Mahmood Amiry-Moghaddam
- Division of Anatomy, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Blindern, Post box 1105, 0317, Oslo, Norway.
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27
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Aquaporin 4 Suppresses Neural Hyperactivity and Synaptic Fatigue and Fine-Tunes Neurotransmission to Regulate Visual Function in the Mouse Retina. Mol Neurobiol 2019; 56:8124-8135. [PMID: 31190144 PMCID: PMC6834759 DOI: 10.1007/s12035-019-01661-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Accepted: 05/22/2019] [Indexed: 01/04/2023]
Abstract
The bidirectional water channel aquaporin 4 (AQP4) is abundantly expressed in the neural tissue. The advantages and disadvantages of AQP4 neural tissue deficiency under pathological conditions, such as inflammation, and relationship with neural diseases, such as Alzheimer’s disease, have been previously reported. However, the physiological functions of AQP4 are not fully understood. Here, we evaluated the role of AQP4 in the mouse retina using Aqp4 knockout (KO) mice. Aqp4 was expressed in Müller glial cells surrounding the synaptic area between photoreceptors and bipolar cells. Both scotopic and photopic electroretinograms showed hyperactive visual responses in KO mice, gradually progressing with age. Moreover, the amplitude reduction after frequent stimuli and synaptic fatigue was more severe in KO mice. Glutamine synthetase, glutamate aspartate transporter, synaptophysin, and the inward potassium channel Kir2.1, but not Kir4.1, were downregulated in KO retinas. KIR2.1 colocalized with AQP4 in Müller glial cells at the synaptic area, and its expression was affected by Aqp4 levels in primary Müller glial cell cultures. Intraocular injection of potassium in wild-type mice led to visual function hyperactivity, as observed in Aqp4 KO mice. Mitochondria molecules, such as Pgc1α and CoxIV, were downregulated, while apoptotic markers were upregulated in KO retinas. AQP4 may fine-tune synaptic activity, most likely by regulating potassium metabolism, at least in part, via collaborating with KIR2.1, and possibly indirectly regulating glutamate kinetics, to inhibit neural hyperactivity and synaptic fatigue which finally affect mitochondria and cause neurodegeneration.
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28
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Chronic stress impairs the aquaporin-4-mediated glymphatic transport through glucocorticoid signaling. Psychopharmacology (Berl) 2019; 236:1367-1384. [PMID: 30607477 DOI: 10.1007/s00213-018-5147-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Accepted: 12/03/2018] [Indexed: 12/12/2022]
Abstract
BACKGROUND The glymphatic system has recently been proposed to function as a brain-wide macroscopic system for the clearance of potentially harmful molecules, such as amyloid beta (e.g., Aβ), from the brain parenchyma. Previous literatures have established that the glymphatic function is dramatically suppressed by aging, traumatic brain injury, and some diseases. However, the effect of chronic stress on the glymphatic function and its underlying mechanism remains largely unknown. METHODS Adult mice were randomly divided into four groups: chronic unpredictable mild stress (CUMS)-treated group, CUMS simultaneously treated with mifepristone (MFP) group, dexamethasone (DEX)-treated group, and control group. Stress response was observed by assessing the change of body weight, plasma corticosterone level, and behavior tests. The level of Aβ42 in cerebral tissue was assessed by ELISA. The glymphatic function was determined by using fluorescence tracer injection. The expression and localization of aquaporin-4 (AQP4) were evaluated by immunohistochemistry and western blot. The transcription level of AQP4 and anchoring molecules was evaluated by real-time PCR. FINDINGS Compared with control group, CUMS-treated mice exhibited the impairment of global glymphatic function especially in the anterior brain. This change was accompanied by the decreased expression and polarization of AQP4, reduced transcription of AQP4, agrin, laminin, and dystroglycan in the anterior cortex. Similarly, the glucocorticoid receptor (GR) agonist DEX exposure could reduce the glymphatic function and AQP4 expression. Moreover, the GR antagonist MFP treatment could significantly rescue the glymphatic function and reverse the expression and polarization of AQP4 impaired by CUMS. CONCLUSION Chronic stress could impair the AQP4-mediated glymphatic transport in the brain through glucocorticoid signaling. Our results also suggest that GR antagonist could be beneficial to rescue the glymphatic function suppressed by chronic stress.
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Rao SB, Katoozi S, Skauli N, Froehner SC, Ottersen OP, Adams ME, Amiry-Moghaddam M. Targeted deletion of β1-syntrophin causes a loss of K ir 4.1 from Müller cell endfeet in mouse retina. Glia 2019; 67:1138-1149. [PMID: 30803043 DOI: 10.1002/glia.23600] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Revised: 01/23/2019] [Accepted: 01/24/2019] [Indexed: 02/02/2023]
Abstract
Proper function of the retina depends heavily on a specialized form of retinal glia called Müller cells. These cells carry out important homeostatic functions that are contingent on their polarized nature. Specifically, the Müller cell endfeet that contact retinal microvessels and the corpus vitreum show a tenfold higher concentration of the inwardly rectifying potassium channel Kir 4.1 than other Müller cell plasma membrane domains. This highly selective enrichment of Kir 4.1 allows K+ to be siphoned through endfoot membranes in a special form of spatial buffering. Here, we show that Kir 4.1 is enriched in endfoot membranes through an interaction with β1-syntrophin. Targeted disruption of this syntrophin caused a loss of Kir 4.1 from Müller cell endfeet without affecting the total level of Kir 4.1 expression in the retina. Targeted disruption of α1-syntrophin had no effect on Kir 4.1 localization. Our findings show that the Kir 4.1 aggregation that forms the basis for K+ siphoning depends on a specific syntrophin isoform that colocalizes with Kir 4.1 in Müller endfoot membranes.
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Affiliation(s)
- Shreyas B Rao
- Division of Anatomy, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Shirin Katoozi
- Division of Anatomy, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Nadia Skauli
- Division of Anatomy, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Stanley C Froehner
- Department of Physiology and Biophysics, University of Washington, Seattle, Western Australia
| | - Ole Petter Ottersen
- Division of Anatomy, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Marvin E Adams
- Department of Physiology and Biophysics, University of Washington, Seattle, Western Australia
| | - Mahmood Amiry-Moghaddam
- Division of Anatomy, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
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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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Hasan-Olive MM, Enger R, Hansson HA, Nagelhus EA, Eide PK. Loss of perivascular aquaporin-4 in idiopathic normal pressure hydrocephalus. Glia 2018; 67:91-100. [DOI: 10.1002/glia.23528] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2018] [Revised: 08/10/2018] [Accepted: 08/15/2018] [Indexed: 12/31/2022]
Affiliation(s)
- Md Mahdi Hasan-Olive
- Department of Neurosurgery; Oslo University Hospital - Rikshospitalet; Oslo Norway
- Institute of Clinical Medicine, Faculty of Medicine; University of Oslo; Oslo Norway
| | - Rune Enger
- GliaLab and Letten Centre, Division of Physiology, Department of Molecular Medicine; Institute of Basic Medical Sciences, University of Oslo; Oslo Norway
- Department of Neurology; Oslo University Hospital - Rikshospitalet; Oslo Norway
| | | | - Erlend A. Nagelhus
- GliaLab and Letten Centre, Division of Physiology, Department of Molecular Medicine; Institute of Basic Medical Sciences, University of Oslo; Oslo Norway
- Department of Neurology; Oslo University Hospital - Rikshospitalet; Oslo Norway
| | - Per Kristian Eide
- Department of Neurosurgery; Oslo University Hospital - Rikshospitalet; Oslo Norway
- Institute of Clinical Medicine, Faculty of Medicine; University of Oslo; Oslo Norway
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32
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Price BR, Norris CM, Sompol P, Wilcock DM. An emerging role of astrocytes in vascular contributions to cognitive impairment and dementia. J Neurochem 2018; 144:644-650. [PMID: 29222909 DOI: 10.1111/jnc.14273] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Revised: 10/30/2017] [Accepted: 11/23/2017] [Indexed: 01/15/2023]
Abstract
Vascular contributions to cognitive impairment and dementia (VCID) is understood to be the second most common cause of dementia after Alzheimer's disease, and is also a frequent comorbidity with Alzheimer's disease. While VCID is widely acknowledged as a key contributor to dementia, the mechanistic underpinnings of VCID remain poorly understood. In this review, we address the potential role of astrocytes in the pathophysiology of VCID. The vast majority of the blood vessels in the brain are surrounded by astrocytic end-feet. Given that astrocytes make up a significant proportion of the cells in the brain, and that astrocytes are usually passively connected to one another through gap junctions, we hypothesize that astrocytes are key mediators of cognitive impairment because of cerebrovascular disease. In this review, we discuss the existing body of literature regarding the role of astrocytes at the vasculature in the brain, and the known consequences of their dysfunction, as well as our hypotheses regarding the role astrocytes play in VCID. This article is part of the Special Issue "Vascular Dementia".
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Affiliation(s)
- Brittani R Price
- Department of Physiology, Sanders-Brown Center on Aging, University of Kentucky, Lexington, Kentucky, USA
| | - Christopher M Norris
- Department of Pharmacology and Nutritional Sciences, University of Kentucky, Lexington, Kentucky, USA
| | - Pradoldej Sompol
- Department of Pharmacology and Nutritional Sciences, University of Kentucky, Lexington, Kentucky, USA
| | - Donna M Wilcock
- Department of Physiology, Sanders-Brown Center on Aging, University of Kentucky, Lexington, Kentucky, USA
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Abstract
Astrocytes are neural cells of ectodermal, neuroepithelial origin that provide for homeostasis and defense of the central nervous system (CNS). Astrocytes are highly heterogeneous in morphological appearance; they express a multitude of receptors, channels, and membrane transporters. This complement underlies their remarkable adaptive plasticity that defines the functional maintenance of the CNS in development and aging. Astrocytes are tightly integrated into neural networks and act within the context of neural tissue; astrocytes control homeostasis of the CNS at all levels of organization from molecular to the whole organ.
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Affiliation(s)
- Alexei Verkhratsky
- The University of Manchester , Manchester , United Kingdom ; Achúcarro Basque Center for Neuroscience, IKERBASQUE, Basque Foundation for Science , Bilbao , Spain ; Department of Neuroscience, University of the Basque Country UPV/EHU and CIBERNED, Leioa, Spain ; Center for Basic and Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen , Copenhagen , Denmark ; and Center for Translational Neuromedicine, University of Rochester Medical Center , Rochester, New York
| | - Maiken Nedergaard
- The University of Manchester , Manchester , United Kingdom ; Achúcarro Basque Center for Neuroscience, IKERBASQUE, Basque Foundation for Science , Bilbao , Spain ; Department of Neuroscience, University of the Basque Country UPV/EHU and CIBERNED, Leioa, Spain ; Center for Basic and Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen , Copenhagen , Denmark ; and Center for Translational Neuromedicine, University of Rochester Medical Center , Rochester, New York
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Verkhratsky A, Nedergaard M. Physiology of Astroglia. Physiol Rev 2018; 98:239-389. [PMID: 29351512 PMCID: PMC6050349 DOI: 10.1152/physrev.00042.2016] [Citation(s) in RCA: 899] [Impact Index Per Article: 149.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Revised: 03/22/2017] [Accepted: 04/27/2017] [Indexed: 02/07/2023] Open
Abstract
Astrocytes are neural cells of ectodermal, neuroepithelial origin that provide for homeostasis and defense of the central nervous system (CNS). Astrocytes are highly heterogeneous in morphological appearance; they express a multitude of receptors, channels, and membrane transporters. This complement underlies their remarkable adaptive plasticity that defines the functional maintenance of the CNS in development and aging. Astrocytes are tightly integrated into neural networks and act within the context of neural tissue; astrocytes control homeostasis of the CNS at all levels of organization from molecular to the whole organ.
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Affiliation(s)
- Alexei Verkhratsky
- The University of Manchester , Manchester , United Kingdom ; Achúcarro Basque Center for Neuroscience, IKERBASQUE, Basque Foundation for Science , Bilbao , Spain ; Department of Neuroscience, University of the Basque Country UPV/EHU and CIBERNED, Leioa, Spain ; Center for Basic and Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen , Copenhagen , Denmark ; and Center for Translational Neuromedicine, University of Rochester Medical Center , Rochester, New York
| | - Maiken Nedergaard
- The University of Manchester , Manchester , United Kingdom ; Achúcarro Basque Center for Neuroscience, IKERBASQUE, Basque Foundation for Science , Bilbao , Spain ; Department of Neuroscience, University of the Basque Country UPV/EHU and CIBERNED, Leioa, Spain ; Center for Basic and Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen , Copenhagen , Denmark ; and Center for Translational Neuromedicine, University of Rochester Medical Center , Rochester, New York
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35
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Bai W, Zhou YG. Homeostasis of the Intraparenchymal-Blood Glutamate Concentration Gradient: Maintenance, Imbalance, and Regulation. Front Mol Neurosci 2017; 10:400. [PMID: 29259540 PMCID: PMC5723322 DOI: 10.3389/fnmol.2017.00400] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Accepted: 11/20/2017] [Indexed: 12/25/2022] Open
Abstract
It is widely accepted that glutamate is the most important excitatory neurotransmitter in the central nervous system (CNS). However, there is also a large amount of glutamate in the blood. Generally, the concentration gradient of glutamate between intraparenchymal and blood environments is stable. However, this gradient is dramatically disrupted under a variety of pathological conditions, resulting in an amplifying cascade that causes a series of pathological reactions in the CNS and peripheral organs. This eventually seriously worsens a patient’s prognosis. These two “isolated” systems are rarely considered as a whole even though they mutually influence each other. In this review, we summarize what is currently known regarding the maintenance, imbalance and regulatory mechanisms that control the intraparenchymal-blood glutamate concentration gradient, discuss the interrelationships between these systems and further explore their significance in clinical practice.
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Affiliation(s)
- Wei Bai
- Molecular Biology Center, State Key Laboratory of Trauma, Burn, and Combined Injury, Research Institute of Surgery and Daping Hospital, Third Military Medical University, Chongqing, China
| | - Yuan-Guo Zhou
- Molecular Biology Center, State Key Laboratory of Trauma, Burn, and Combined Injury, Research Institute of Surgery and Daping Hospital, Third Military Medical University, Chongqing, China
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36
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Lee ML, Martinez-Lozada Z, Krizman EN, Robinson MB. Brain endothelial cells induce astrocytic expression of the glutamate transporter GLT-1 by a Notch-dependent mechanism. J Neurochem 2017; 143:489-506. [PMID: 28771710 DOI: 10.1111/jnc.14135] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Revised: 07/07/2017] [Accepted: 07/13/2017] [Indexed: 01/13/2023]
Abstract
Neuron-secreted factors induce astrocytic expression of the glutamate transporter, GLT-1 (excitatory amino acid transporter 2). In addition to their elaborate anatomic relationships with neurons, astrocytes also have processes that extend to and envelop the vasculature. Although previous studies have demonstrated that brain endothelia contribute to astrocyte differentiation and maturation, the effects of brain endothelia on astrocytic expression of GLT-1 have not been examined. In this study, we tested the hypothesis that endothelia induce expression of GLT-1 by co-culturing astrocytes from mice that utilize non-coding elements of the GLT-1 gene to control expression of reporter proteins with the mouse endothelial cell line, bEND.3. We found that endothelia increased steady state levels of reporter and GLT-1 mRNA/protein. Co-culturing with primary rat brain endothelia also increases reporter protein, GLT-1 protein, and GLT-1-mediated glutamate uptake. The Janus kinase/signal transducer and activator of transcription 3, bone morphogenic protein/transforming growth factor β, and nitric oxide pathways have been implicated in endothelia-to-astrocyte signaling; we provide multiple lines of evidence that none of these pathways mediate the effects of endothelia on astrocytic GLT-1 expression. Using transwells with a semi-permeable membrane, we demonstrate that the effects of the bEND.3 cell line are dependent upon contact. Notch has also been implicated in endothelia-astrocyte signaling in vitro and in vivo. The first step of Notch signaling requires cleavage of Notch intracellular domain by γ-secretase. We demonstrate that the γ-secretase inhibitor N-[N-(3,5-difluorophenacetyl)-l-alanyl]-S-phenylglycine t-butyl ester blocks endothelia-induced increases in GLT-1. We show that the levels of Notch intracellular domain are higher in nuclei of astrocytes co-cultured with endothelia, an effect also blocked by N-[N-(3,5-difluorophenacetyl)-l-alanyl]-S-phenylglycine t-butyl ester. Finally, infection of co-cultures with shRNA directed against recombination signal binding protein for immunoglobulin kappa J, a Notch effector, also reduces endothelia-dependent increases in enhanced green fluorescent protein and GLT-1. Together, these studies support a novel role for Notch in endothelia-dependent induction of GLT-1 expression. Cover Image for this issue: doi. 10.1111/jnc.13825.
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Affiliation(s)
- Meredith L Lee
- Departments of Pediatrics, Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Zila Martinez-Lozada
- Departments of Pediatrics, Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Elizabeth N Krizman
- Departments of Pediatrics, Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Michael B Robinson
- Departments of Pediatrics, Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, Pennsylvania, USA.,Systems Pharmacology and Translational Therapeutics, Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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37
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Lee ML, Martinez-Lozada Z, Krizman EN, Robinson MB. Brain endothelial cells induce astrocytic expression of the glutamate transporter GLT-1 by a Notch-dependent mechanism. J Neurochem 2017. [PMID: 28771710 DOI: 10.1111/jnc.13825] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Neuron-secreted factors induce astrocytic expression of the glutamate transporter, GLT-1 (excitatory amino acid transporter 2). In addition to their elaborate anatomic relationships with neurons, astrocytes also have processes that extend to and envelop the vasculature. Although previous studies have demonstrated that brain endothelia contribute to astrocyte differentiation and maturation, the effects of brain endothelia on astrocytic expression of GLT-1 have not been examined. In this study, we tested the hypothesis that endothelia induce expression of GLT-1 by co-culturing astrocytes from mice that utilize non-coding elements of the GLT-1 gene to control expression of reporter proteins with the mouse endothelial cell line, bEND.3. We found that endothelia increased steady state levels of reporter and GLT-1 mRNA/protein. Co-culturing with primary rat brain endothelia also increases reporter protein, GLT-1 protein, and GLT-1-mediated glutamate uptake. The Janus kinase/signal transducer and activator of transcription 3, bone morphogenic protein/transforming growth factor β, and nitric oxide pathways have been implicated in endothelia-to-astrocyte signaling; we provide multiple lines of evidence that none of these pathways mediate the effects of endothelia on astrocytic GLT-1 expression. Using transwells with a semi-permeable membrane, we demonstrate that the effects of the bEND.3 cell line are dependent upon contact. Notch has also been implicated in endothelia-astrocyte signaling in vitro and in vivo. The first step of Notch signaling requires cleavage of Notch intracellular domain by γ-secretase. We demonstrate that the γ-secretase inhibitor N-[N-(3,5-difluorophenacetyl)-l-alanyl]-S-phenylglycine t-butyl ester blocks endothelia-induced increases in GLT-1. We show that the levels of Notch intracellular domain are higher in nuclei of astrocytes co-cultured with endothelia, an effect also blocked by N-[N-(3,5-difluorophenacetyl)-l-alanyl]-S-phenylglycine t-butyl ester. Finally, infection of co-cultures with shRNA directed against recombination signal binding protein for immunoglobulin kappa J, a Notch effector, also reduces endothelia-dependent increases in enhanced green fluorescent protein and GLT-1. Together, these studies support a novel role for Notch in endothelia-dependent induction of GLT-1 expression. Cover Image for this issue: doi. 10.1111/jnc.13825.
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Affiliation(s)
- Meredith L Lee
- Departments of Pediatrics, Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Zila Martinez-Lozada
- Departments of Pediatrics, Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Elizabeth N Krizman
- Departments of Pediatrics, Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Michael B Robinson
- Departments of Pediatrics, Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, Pennsylvania, USA.,Systems Pharmacology and Translational Therapeutics, Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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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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Tehrani S, Davis L, Cepurna WO, Choe TE, Lozano DC, Monfared A, Cooper L, Cheng J, Johnson EC, Morrison JC. Astrocyte Structural and Molecular Response to Elevated Intraocular Pressure Occurs Rapidly and Precedes Axonal Tubulin Rearrangement within the Optic Nerve Head in a Rat Model. PLoS One 2016; 11:e0167364. [PMID: 27893827 PMCID: PMC5125687 DOI: 10.1371/journal.pone.0167364] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Accepted: 11/12/2016] [Indexed: 02/01/2023] Open
Abstract
Glaucomatous axon injury occurs at the level of the optic nerve head (ONH) in response to uncontrolled intraocular pressure (IOP). The temporal response of ONH astrocytes (glial cells responsible for axonal support) to elevated IOP remains unknown. Here, we evaluate the response of actin-based astrocyte extensions and integrin-based signaling within the ONH to 8 hours of IOP elevation in a rat model. IOP elevation of 60 mm Hg was achieved under isoflurane anesthesia using anterior chamber cannulation connected to a saline reservoir. ONH astrocytic extension orientation was significantly and regionally rearranged immediately after IOP elevation (inferior ONH, 43.2° ± 13.3° with respect to the anterior-posterior axis versus 84.1° ± 1.3° in controls, p<0.05), and re-orientated back to baseline orientation 1 day post IOP normalization. ONH axonal microtubule filament label intensity was significantly reduced 1 and 3 days post IOP normalization, and returned to control levels on day 5. Phosphorylated focal adhesion kinase (FAK) levels steadily decreased after IOP normalization, while levels of phosphorylated paxillin (a downstream target of FAK involved in focal adhesion dynamics) were significantly elevated 5 days post IOP normalization. The levels of phosphorylated cortactin (a downstream target of Src kinase involved in actin polymerization) were significantly elevated 1 and 3 days post IOP normalization and returned to control levels by day 5. No significant axon degeneration was noted by morphologic assessment up to 5 days post IOP normalization. Actin-based astrocyte structure and signaling within the ONH are significantly altered within hours after IOP elevation and prior to axonal cytoskeletal rearrangement, producing some responses that recover rapidly and others that persist for days despite IOP normalization.
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Affiliation(s)
- Shandiz Tehrani
- Casey Eye Institute, Department of Ophthalmology, Oregon Health & Science University, Portland, Oregon, United States of America
- * E-mail:
| | - Lauren Davis
- Casey Eye Institute, Department of Ophthalmology, Oregon Health & Science University, Portland, Oregon, United States of America
| | - William O. Cepurna
- Casey Eye Institute, Department of Ophthalmology, Oregon Health & Science University, Portland, Oregon, United States of America
| | - Tiffany E. Choe
- Casey Eye Institute, Department of Ophthalmology, Oregon Health & Science University, Portland, Oregon, United States of America
| | - Diana C. Lozano
- Casey Eye Institute, Department of Ophthalmology, Oregon Health & Science University, Portland, Oregon, United States of America
| | - Ashley Monfared
- Casey Eye Institute, Department of Ophthalmology, Oregon Health & Science University, Portland, Oregon, United States of America
| | - Lauren Cooper
- Casey Eye Institute, Department of Ophthalmology, Oregon Health & Science University, Portland, Oregon, United States of America
| | - Joshua Cheng
- Casey Eye Institute, Department of Ophthalmology, Oregon Health & Science University, Portland, Oregon, United States of America
| | - Elaine C. Johnson
- Casey Eye Institute, Department of Ophthalmology, Oregon Health & Science University, Portland, Oregon, United States of America
| | - John C. Morrison
- Casey Eye Institute, Department of Ophthalmology, Oregon Health & Science University, Portland, Oregon, United States of America
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Time-course of glial changes in the hyperhomocysteinemia model of vascular cognitive impairment and dementia (VCID). Neuroscience 2016; 341:42-51. [PMID: 27890830 DOI: 10.1016/j.neuroscience.2016.11.024] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Revised: 11/10/2016] [Accepted: 11/17/2016] [Indexed: 12/31/2022]
Abstract
Vascular cognitive impairment and dementia (VCID) is the second leading cause of dementia behind Alzheimer's disease (AD) and is a frequent co-morbidity with AD. Despite its prevalence, little is known about the molecular mechanisms underlying the cognitive dysfunction resulting from cerebrovascular disease. Astrocytic end-feet almost completely surround intraparenchymal blood vessels in the brain and express a variety of channels and markers indicative of their specialized functions in the maintenance of ionic and osmotic homeostasis and gliovascular signaling. These functions are mediated by end-foot enrichment of the aquaporin 4 water channel (AQP4), the inward rectifying potassium channel Kir4.1 and the calcium-dependent potassium channel MaxiK. Using our hyperhomocysteinemia (HHcy) model of VCID we examined the time-course of astrocytic end-foot changes along with cognitive and neuroinflammatory outcomes. We found that there were significant astrocytic end-foot disruptions in the HHcy model. AQP4 becomes dislocalized from the end-feet, there is a loss of Kir4.1 and MaxiK protein expression, as well as a loss of the Dp71 protein known to anchor the Kir4.1, MaxiK and AQP4 channels to the end-foot membrane. Neuroinflammation occurs prior to the astrocytic changes, while cognitive impairment continues to decline with the exacerbation of the astrocytic changes. We have previously reported similar astrocytic changes in models of cerebral amyloid angiopathy (CAA) and therefore, we believe astrocytic end-foot disruption could represent a common cellular mechanism of VCID and may be a target for therapeutic development.
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Factors determining the density of AQP4 water channel molecules at the brain-blood interface. Brain Struct Funct 2016; 222:1753-1766. [PMID: 27629271 PMCID: PMC5406442 DOI: 10.1007/s00429-016-1305-y] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2016] [Accepted: 09/04/2016] [Indexed: 10/27/2022]
Abstract
Perivascular endfeet of astrocytes are enriched with aquaporin-4 (AQP4)-a water channel that is critically involved in water transport at the brain-blood interface and that recently was identified as a key molecule in a system for waste clearance. The factors that determine the size of the perivascular AQP4 pool remain to be identified. Here we show that the size of this pool differs considerably between brain regions, roughly mirroring regional differences in Aqp4 mRNA copy numbers. We demonstrate that a targeted deletion of α-syntrophin-a member of the dystrophin complex responsible for AQP4 anchoring-removes a substantial and fairly constant proportion (79-94 %) of the perivascular AQP4 pool across the central nervous system (CNS). Quantitative immunogold analyses of AQP4 and α-syntrophin in perivascular membranes indicate that there is a fixed stoichiometry between these two molecules. Both molecules occur at higher densities in endfoot membrane domains facing pericytes than in endfoot membrane domains facing endothelial cells. Our data suggest that irrespective of region, endfoot targeting of α-syntrophin is the single most important factor determining the size of the perivascular AQP4 pool and hence the capacity for water transport at the brain-blood interface.
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Gleiser C, Wagner A, Fallier-Becker P, Wolburg H, Hirt B, Mack AF. Aquaporin-4 in Astroglial Cells in the CNS and Supporting Cells of Sensory Organs-A Comparative Perspective. Int J Mol Sci 2016; 17:E1411. [PMID: 27571065 PMCID: PMC5037691 DOI: 10.3390/ijms17091411] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Revised: 08/22/2016] [Accepted: 08/23/2016] [Indexed: 01/28/2023] Open
Abstract
The main water channel of the brain, aquaporin-4 (AQP4), is one of the classical water-specific aquaporins. It is expressed in many epithelial tissues in the basolateral membrane domain. It is present in the membranes of supporting cells in most sensory organs in a specifically adapted pattern: in the supporting cells of the olfactory mucosa, AQP4 occurs along the basolateral aspects, in mammalian retinal Müller cells it is highly polarized. In the cochlear epithelium of the inner ear, it is expressed basolaterally in some cells but strictly basally in others. Within the central nervous system, aquaporin-4 (AQP4) is expressed by cells of the astroglial family, more specifically, by astrocytes and ependymal cells. In the mammalian brain, AQP4 is located in high density in the membranes of astrocytic endfeet facing the pial surface and surrounding blood vessels. At these locations, AQP4 plays a role in the maintenance of ionic homeostasis and volume regulation. This highly polarized expression has not been observed in the brain of fish where astroglial cells have long processes and occur mostly as radial glial cells. In the brain of the zebrafish, AQP4 immunoreactivity is found along the radial extent of astroglial cells. This suggests that the polarized expression of AQP4 was not present at all stages of evolution. Thus, a polarized expression of AQP4 as part of a control mechanism for a stable ionic environment and water balanced occurred at several locations in supporting and glial cells during evolution. This initially basolateral membrane localization of AQP4 is shifted to highly polarized expression in astrocytic endfeet in the mammalian brain and serves as a part of the neurovascular unit to efficiently maintain homeostasis.
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Affiliation(s)
- Corinna Gleiser
- Institute of Clinical Anatomy and Cell Analysis, Eberhard Karls Universität Tübingen, 72074 Tübingen, Germany.
| | - Andreas Wagner
- Institute of Clinical Anatomy and Cell Analysis, Eberhard Karls Universität Tübingen, 72074 Tübingen, Germany.
| | - Petra Fallier-Becker
- Institute of Pathology and Neuropathology, Eberhard Karls Universität Tübingen, 72076 Tubingen, Germany.
| | - Hartwig Wolburg
- Institute of Pathology and Neuropathology, Eberhard Karls Universität Tübingen, 72076 Tubingen, Germany.
| | - Bernhard Hirt
- Institute of Clinical Anatomy and Cell Analysis, Eberhard Karls Universität Tübingen, 72074 Tübingen, Germany.
| | - Andreas F Mack
- Institute of Clinical Anatomy and Cell Analysis, Eberhard Karls Universität Tübingen, 72074 Tübingen, Germany.
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Neuroimmunological Implications of AQP4 in Astrocytes. Int J Mol Sci 2016; 17:ijms17081306. [PMID: 27517922 PMCID: PMC5000703 DOI: 10.3390/ijms17081306] [Citation(s) in RCA: 91] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Revised: 07/28/2016] [Accepted: 08/04/2016] [Indexed: 12/18/2022] Open
Abstract
The brain has high-order functions and is composed of several kinds of cells, such as neurons and glial cells. It is becoming clear that many kinds of neurodegenerative diseases are more-or-less influenced by astrocytes, which are a type of glial cell. Aquaporin-4 (AQP4), a membrane-bound protein that regulates water permeability is a member of the aquaporin family of water channel proteins that is expressed in the endfeet of astrocytes in the central nervous system (CNS). Recently, AQP4 has been shown to function, not only as a water channel protein, but also as an adhesion molecule that is involved in cell migration and neuroexcitation, synaptic plasticity, and learning/memory through mechanisms involved in long-term potentiation or long-term depression. The most extensively examined role of AQP4 is its ability to act as a neuroimmunological inducer. Previously, we showed that AQP4 plays an important role in neuroimmunological functions in injured mouse brain in concert with the proinflammatory inducer osteopontin (OPN). The aim of this review is to summarize the functional implication of AQP4, focusing especially on its neuroimmunological roles. This review is a good opportunity to compile recent knowledge and could contribute to the therapeutic treatment of autoimmune diseases through strategies targeting AQP4. Finally, the author would like to hypothesize on AQP4’s role in interaction between reactive astrocytes and reactive microglial cells, which might occur in neurodegenerative diseases. Furthermore, a therapeutic strategy for AQP4-related neurodegenerative diseases is proposed.
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Posati T, Pistone A, Saracino E, Formaggio F, Mola MG, Troni E, Sagnella A, Nocchetti M, Barbalinardo M, Valle F, Bonetti S, Caprini M, Nicchia GP, Zamboni R, Muccini M, Benfenati V. A Nanoscale Interface Promoting Molecular and Functional Differentiation of Neural Cells. Sci Rep 2016; 6:31226. [PMID: 27503424 PMCID: PMC4977496 DOI: 10.1038/srep31226] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Accepted: 07/04/2016] [Indexed: 12/11/2022] Open
Abstract
Potassium channels and aquaporins expressed by astrocytes are key players in the maintenance of cerebral homeostasis and in brain pathophysiologies. One major challenge in the study of astrocyte membrane channels in vitro, is that their expression pattern does not resemble the one observed in vivo. Nanostructured interfaces represent a significant resource to control the cellular behaviour and functionalities at micro and nanoscale as well as to generate novel and more reliable models to study astrocytes in vitro. However, the potential of nanotechnologies in the manipulation of astrocytes ion channels and aquaporins has never been previously reported. Hydrotalcite-like compounds (HTlc) are layered materials with increasing potential as biocompatible nanoscale interface. Here, we evaluate the effect of the interaction of HTlc nanoparticles films with primary rat neocortical astrocytes. We show that HTlc films are biocompatible and do not promote gliotic reaction, while favouring astrocytes differentiation by induction of F-actin fibre alignment and vinculin polarization. Western Blot, Immunofluorescence and patch-clamp revealed that differentiation was accompanied by molecular and functional up-regulation of both inward rectifying potassium channel Kir 4.1 and aquaporin 4, AQP4. The reported results pave the way to engineering novel in vitro models to study astrocytes in a in vivo like condition.
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Affiliation(s)
- Tamara Posati
- Consiglio Nazionale delle Ricerche (CNR), Istituto per lo Sintesi Organica e la Fotoreattività (ISOF), via Gobetti, 101, 40129, Bologna, Italy
| | - Assunta Pistone
- Consiglio Nazionale delle Ricerche (CNR), Istituto per lo Studio dei Materiali Nanostrutturati (ISMN), via Gobetti, 101, 40129, Bologna, Italy
| | - Emanuela Saracino
- Consiglio Nazionale delle Ricerche (CNR), Istituto per lo Studio dei Materiali Nanostrutturati (ISMN), via Gobetti, 101, 40129, Bologna, Italy
| | - Francesco Formaggio
- Consiglio Nazionale delle Ricerche (CNR), Istituto per lo Studio dei Materiali Nanostrutturati (ISMN), via Gobetti, 101, 40129, Bologna, Italy
| | - Maria Grazia Mola
- Dipartimento di Bioscienze, Biotecnologie e Biofarmaceutica, Università degli Studi di Bari “Aldo Moro”, Via Amendola 165/A, 70126, Bari, Italy
| | - Elisabetta Troni
- Consiglio Nazionale delle Ricerche (CNR), Istituto per lo Sintesi Organica e la Fotoreattività (ISOF), via Gobetti, 101, 40129, Bologna, Italy
| | - Anna Sagnella
- Laboratorio di Micro e Submicro Tecnologie abilitanti dell’Emilia-Romagna (MIST E-R), Via P. Gobetti 101, I-40129 Bologna, Italy
| | - Morena Nocchetti
- Dipartimento di Scienze Farmaceutiche, University of Perugia, Via del Liceo 1, 06123, Perugia, Italy
| | - Marianna Barbalinardo
- Consiglio Nazionale delle Ricerche (CNR), Istituto per lo Studio dei Materiali Nanostrutturati (ISMN), via Gobetti, 101, 40129, Bologna, Italy
| | - Francesco Valle
- Consiglio Nazionale delle Ricerche (CNR), Istituto per lo Studio dei Materiali Nanostrutturati (ISMN), via Gobetti, 101, 40129, Bologna, Italy
| | - Simone Bonetti
- Consiglio Nazionale delle Ricerche (CNR), Istituto per lo Studio dei Materiali Nanostrutturati (ISMN), via Gobetti, 101, 40129, Bologna, Italy
| | - Marco Caprini
- Department of Pharmacy and Biotechnology, via S. Donato 19/2, University of Bologna, 40127 Bologna, Italy
| | - Grazia Paola Nicchia
- Dipartimento di Bioscienze, Biotecnologie e Biofarmaceutica, Università degli Studi di Bari “Aldo Moro”, Via Amendola 165/A, 70126, Bari, Italy
| | - Roberto Zamboni
- Consiglio Nazionale delle Ricerche (CNR), Istituto per lo Sintesi Organica e la Fotoreattività (ISOF), via Gobetti, 101, 40129, Bologna, Italy
| | - Michele Muccini
- Consiglio Nazionale delle Ricerche (CNR), Istituto per lo Studio dei Materiali Nanostrutturati (ISMN), via Gobetti, 101, 40129, Bologna, Italy
| | - Valentina Benfenati
- Consiglio Nazionale delle Ricerche (CNR), Istituto per lo Sintesi Organica e la Fotoreattività (ISOF), via Gobetti, 101, 40129, Bologna, Italy
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Thompson EG, Sontheimer H. A role for ion channels in perivascular glioma invasion. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2016; 45:635-648. [PMID: 27424110 DOI: 10.1007/s00249-016-1154-x] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2016] [Revised: 06/21/2016] [Accepted: 07/01/2016] [Indexed: 11/28/2022]
Abstract
Malignant gliomas are devastating tumors, frequently killing those diagnosed in little over a year. The profuse infiltration of glioma cells into healthy tissue surrounding the main tumor mass is one of the major obstacles limiting the improvement of patient survival. Migration along the abluminal side of blood vessels is one of the salient features of glioma cell invasion. Invading glioma cells are attracted to the vascular network, in part by the neuropeptide bradykinin, where glioma cells actively modify the gliovascular interface and undergo volumetric alterations to navigate the confined space. Critical to these volume modifications is a proposed hydrodynamic model that involves the flux of ions in and out of the cell, followed by osmotically obligated water. Ion and water channels expressed by the glioma cell are essential in this model of invasion and make opportune therapeutic targets. Lastly, there is growing evidence that vascular-associated glioma cells are able to control the vascular tone, presumably to free up space for invasion and growth. The unique mechanisms that enable perivascular glioma invasion may offer critical targets for therapeutic intervention in this devastating disease. Indeed, a chloride channel-blocking peptide has already been successfully tested in human clinical trials.
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Affiliation(s)
- Emily G Thompson
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL, USA.,Center for Glial Biology in Health, Disease, and Cancer, Virginia Tech Carilion Research Institute, Roanoke, VA, USA
| | - Harald Sontheimer
- Center for Glial Biology in Health, Disease, and Cancer, Virginia Tech Carilion Research Institute, Roanoke, VA, USA. .,Virginia Tech School of Neuroscience, Blacksburg, VA, USA.
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Di Benedetto B, Malik VA, Begum S, Jablonowski L, Gómez-González GB, Neumann ID, Rupprecht R. Fluoxetine Requires the Endfeet Protein Aquaporin-4 to Enhance Plasticity of Astrocyte Processes. Front Cell Neurosci 2016; 10:8. [PMID: 26869881 PMCID: PMC4735422 DOI: 10.3389/fncel.2016.00008] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2015] [Accepted: 01/11/2016] [Indexed: 01/12/2023] Open
Abstract
Morphological alterations in astrocytes are characteristic for post mortem brains of patients affected by major depressive disorder (MDD). Recently, a significant reduction in the coverage of blood vessels (BVs) by aquaporin-4 (AQP-4)-positive astrocyte endfeet has been shown in the prefrontal cortex (PFC) of MDD patients, suggesting that either alterations in the morphology of endfeet or in AQP-4 distribution might be responsible for the disease phenotype or constitute a consequence of its progress. Antidepressant drugs (ADs) regulate the expression of several proteins, including astrocyte-specific ones. Thus, they may target AQP-4 to induce morphological changes in astrocytes and restore their proper shape or relocate AQP-4 to endfeet. Using an animal model of depression, rats selectively bred for high anxiety-like behavior (HAB), we confirmed a reduced coverage of BVs in the adult PFC by AQP-4-immunoreactive (AQP-4-IR) astrocyte processes with respect to non-selected Wistar rats (NAB), thereby validating it for our study. A further evaluation of the morphology of astrocyte in brain slices (ex vivo) and in vitro using an antibody against the astrocyte-specific cytoskeletal protein glial fibrillary acidic protein (GFAP) revealed that HAB astrocytes extended less processes than NAB cells. Furthermore, short-term drug treatment in vitro with the AD fluoxetine (FLX) was sufficient to increase the plasticity of astrocyte processes, enhancing their number in NAB-derived cells and recovering their basal number in HAB-derived cells. This enhanced FLX-dependent plasticity occurred, however, only in the presence of intact AQP-4, as demonstrated by the lack of effect after the downregulation of AQP-4 with RNAi in both NAB and HAB cells. Nonetheless, a similar short-term treatment did neither modulate the coverage of BVs with AQP-4-positive astrocyte endfeet in NAB nor in HAB rats, although dosage and time of treatment were sufficient to fully recover GFAP expression in HAB brains. Thus, we suggest that longer treatment regimes may be needed to properly restore the coverage of BVs or to relocate AQP-4 to astrocyte endfeet. In conclusion, FLX requires AQP-4 to modulate the plasticity of astrocyte processes and this effect might be essential to re-establish a functional glia-vasculature interface necessary for a physiological communication between bloodstream and brain parenchyma.
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Affiliation(s)
- Barbara Di Benedetto
- Laboratory of Neuro-Glia Pharmacology, Department of Psychiatry and Psychotherapy, University of Regensburg Regensburg, Germany
| | - Victoria A Malik
- Laboratory of Neuro-Glia Pharmacology, Department of Psychiatry and Psychotherapy, University of Regensburg Regensburg, Germany
| | - Salina Begum
- Laboratory of Neuro-Glia Pharmacology, Department of Psychiatry and Psychotherapy, University of Regensburg Regensburg, Germany
| | - Lena Jablonowski
- Laboratory of Neuro-Glia Pharmacology, Department of Psychiatry and Psychotherapy, University of Regensburg Regensburg, Germany
| | - Gabriela B Gómez-González
- Laboratory of Neuro-Glia Pharmacology, Department of Psychiatry and Psychotherapy, University of Regensburg Regensburg, Germany
| | - Inga D Neumann
- Department of Neurobiology, University of Regensburg Regensburg, Germany
| | - Rainer Rupprecht
- Laboratory of Neuro-Glia Pharmacology, Department of Psychiatry and Psychotherapy, University of Regensburg Regensburg, Germany
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47
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Glial-endothelial crosstalk regulates blood–brain barrier function. Curr Opin Pharmacol 2016; 26:39-46. [DOI: 10.1016/j.coph.2015.09.010] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Revised: 09/23/2015] [Accepted: 09/27/2015] [Indexed: 12/21/2022]
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48
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Simon MJ, Iliff JJ. Regulation of cerebrospinal fluid (CSF) flow in neurodegenerative, neurovascular and neuroinflammatory disease. Biochim Biophys Acta Mol Basis Dis 2015; 1862:442-51. [PMID: 26499397 DOI: 10.1016/j.bbadis.2015.10.014] [Citation(s) in RCA: 192] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2015] [Revised: 09/23/2015] [Accepted: 10/19/2015] [Indexed: 12/20/2022]
Abstract
Cerebrospinal fluid (CSF) circulation and turnover provides a sink for the elimination of solutes from the brain interstitium, serving an important homeostatic role for the function of the central nervous system. Disruption of normal CSF circulation and turnover is believed to contribute to the development of many diseases, including neurodegenerative conditions such as Alzheimer's disease, ischemic and traumatic brain injury, and neuroinflammatory conditions such as multiple sclerosis. Recent insights into CSF biology suggesting that CSF and interstitial fluid exchange along a brain-wide network of perivascular spaces termed the 'glymphatic' system suggest that CSF circulation may interact intimately with glial and vascular function to regulate basic aspects of brain function. Dysfunction within this glial vascular network, which is a feature of the aging and injured brain, is a potentially critical link between brain injury, neuroinflammation and the development of chronic neurodegeneration. Ongoing research within this field may provide a powerful new framework for understanding the common links between neurodegenerative, neurovascular and neuroinflammatory disease, in addition to providing potentially novel therapeutic targets for these conditions. This article is part of a Special Issue entitled: Neuro Inflammation edited by Helga E. de Vries and Markus Schwaninger.
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Affiliation(s)
- Matthew J Simon
- Department of Anesthesiology and Perioperative Medicine, Oregon Health & Science University, Portland, OR, USA; Neuroscience Graduate Program, Oregon Health & Science University, Portland, OR, USA
| | - Jeffrey J Iliff
- Department of Anesthesiology and Perioperative Medicine, Oregon Health & Science University, Portland, OR, USA; Knight Cardiovascular Institute, Oregon Health & Science University, Portland, OR, USA; Neuroscience Graduate Program, Oregon Health & Science University, Portland, OR, USA.
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49
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Hubbard JA, Hsu MS, Seldin MM, Binder DK. Expression of the Astrocyte Water Channel Aquaporin-4 in the Mouse Brain. ASN Neuro 2015; 7:7/5/1759091415605486. [PMID: 26489685 PMCID: PMC4623559 DOI: 10.1177/1759091415605486] [Citation(s) in RCA: 91] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Aquaporin-4 (AQP4) is a bidirectional water channel that is found on astrocytes throughout the central nervous system. Expression is particularly high around areas in contact with cerebrospinal fluid, suggesting that AQP4 plays a role in fluid exchange between the cerebrospinal fluid compartments and the brain. Despite its significant role in the brain, the overall spatial and region-specific distribution of AQP4 has yet to be fully characterized. In this study, we used Western blotting and immunohistochemical techniques to characterize AQP4 expression and localization throughout the mouse brain. We observed AQP4 expression throughout the forebrain, subcortical areas, and brainstem. AQP4 protein levels were highest in the cerebellum with lower expression in the cortex and hippocampus. We found that AQP4 immunoreactivity was profuse on glial cells bordering ventricles, blood vessels, and subarachnoid space. Throughout the brain, AQP4 was expressed on astrocytic end-feet surrounding blood vessels but was also heterogeneously expressed in brain tissue parenchyma and neuropil, often with striking laminar specificity. In the cerebellum, we showed that AQP4 colocalized with the proteoglycan brevican, which is synthesized by and expressed on cerebellar astrocytes. Despite the high abundance of AQP4 in the cerebellum, its functional significance has yet to be investigated. Given the known role of AQP4 in synaptic plasticity in the hippocampus, the widespread and region-specific expression pattern of AQP4 suggests involvement not only in fluid balance and ion homeostasis but also local synaptic plasticity and function in distinct brain circuits.
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Affiliation(s)
- Jacqueline A Hubbard
- Center for Glial-Neuronal Interactions, Division of Biomedical Sciences, University of California, Riverside, CA, USA
| | - Mike S Hsu
- Center for Glial-Neuronal Interactions, Division of Biomedical Sciences, University of California, Riverside, CA, USA
| | - Marcus M Seldin
- Division of Cardiology, University of California, Los Angeles, CA, USA
| | - Devin K Binder
- Center for Glial-Neuronal Interactions, Division of Biomedical Sciences, University of California, Riverside, CA, USA
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