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Cibelli A, Ballesteros-Gomez D, McCutcheon S, Yang GL, Bispo A, Krawchuk M, Piedra G, Spray DC. Astrocytes sense glymphatic-level shear stress through the interaction of sphingosine-1-phosphate with Piezo1. iScience 2024; 27:110069. [PMID: 38868201 PMCID: PMC11167526 DOI: 10.1016/j.isci.2024.110069] [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: 12/08/2023] [Revised: 04/09/2024] [Accepted: 05/17/2024] [Indexed: 06/14/2024] Open
Abstract
Astrocyte endfeet enwrap brain vasculature, forming a boundary for perivascular glymphatic flow of fluid and solutes along and across the astrocyte endfeet into the brain parenchyma. We evaluated astrocyte sensitivity to shear stress generated by such flow, finding a set point for downstream calcium signaling that is below about 0.1 dyn/cm2. This set point is modulated by albumin levels encountered in cerebrospinal fluid (CSF) under normal conditions and following a blood-brain barrier breach or immune response. The astrocyte mechanosome responsible for the detection of shear stress includes sphingosine-1-phosphate (S1P)-mediated sensitization of the mechanosensor Piezo1. Fluid flow through perivascular channels delimited by vessel wall and astrocyte endfeet thus generates sufficient shear stress to activate astrocytes, thereby potentially controlling vasomotion and parenchymal perfusion. Moreover, S1P receptor signaling establishes a set point for Piezo1 activation that is finely tuned to coincide with CSF albumin levels and to the low shear forces resulting from glymphatic flow.
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Affiliation(s)
- Antonio Cibelli
- Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | | | - Sean McCutcheon
- Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Greta L. Yang
- Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Ashley Bispo
- Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Michael Krawchuk
- Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Giselle Piedra
- Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - David C. Spray
- Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461, USA
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2
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Ballesteros-Gomez D, McCutcheon S, Yang GL, Cibelli A, Bispo A, Krawchuk M, Piedra G, Spray DC. Astrocyte sensitivity to glymphatic shear stress is amplified by albumin and mediated by the interaction of sphingosine 1 phosphate with Piezo1. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.06.565884. [PMID: 37986983 PMCID: PMC10659372 DOI: 10.1101/2023.11.06.565884] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2023]
Abstract
Astrocyte endfeet enwrap brain vasculature, forming a boundary for perivascular glymphatic flow of fluid and solutes along and across the astrocyte endfeet into the brain parenchyma. To determine whether astrocytes may sense and respond to the shear forces generated by glymphatic flow, we examined intracellular calcium (Ca 2+ ) changes evoked in astrocytes to brief fluid flow applied in calibrated microfluidic chambers. Shear stresses < 20 dyn/cm 2 failed to evoke Ca 2+ responses in the absence of albumin, but cells responded to shear stress below 1 dyn/cm 2 when as little as 5 μM albumin was present in flow medium. A role for extracellular matrix in mechanotransduction was indicated by reduced sensitivity after degradation of heparan sulfate proteoglycan. Sphingosine-1-phosphate (S1P) amplified shear responses in the absence of albumin, whereas mechanosensitivity was attenuated by the S1P receptor blocker fingolimod. Piezo1 participated in the transduction as revealed by blockade by the spider toxin GsMTX and amplification by the chemical modulator Yoda1, even in absence of albumin or S1P. Our findings that astrocytes are exquisitely sensitive to shear stress and that sensitivity is greatly amplified by albumin concentrations encountered in normal and pathological CSF predict that perivascular astrocytes are responsive to glymphatic shear stress and that responsiveness is augmented by elevated CSF protein. S1P receptor signaling thus establishes a setpoint for Piezo1 activation that is finely tuned to coincide with albumin level in CSF and to the low shear forces resulting from glymphatic flow. Graphical abstract Astrocyte endfoot responds to glymphatic shear stress when albumin is present. Mechanism involves sphingosine-1-phosphate (S1P) binding to its receptor (S1PR), activating phospholipase C (PLC) and thereby sensitizing the response of Piezo1 to flow. Ca 2+ influx triggers Ca 2+ release from intracellular stores and further downstream signaling, thereby modulating parenchymal perfusion. Illustration created using BioRender.com.
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3
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Abbasloo E, Khaksari M, Sanjari M, Kobeissy F, Thomas TC. Carvacrol decreases blood-brain barrier permeability post-diffuse traumatic brain injury in rats. Sci Rep 2023; 13:14546. [PMID: 37666857 PMCID: PMC10477335 DOI: 10.1038/s41598-023-40915-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Accepted: 08/18/2023] [Indexed: 09/06/2023] Open
Abstract
Previously, we showed that Satureja Khuzestanica Jamzad essential oil (SKEO) and its major component, carvacrol (CAR), 5-isopropyl-2-methylphenol, has anti-inflammatory, anti-apoptotic, and anti-edematous properties after experimental traumatic brain injury (TBI) in rats. CAR, predominantly found in Lamiaceae family (Satureja and Oregano), is lipophilic, allowing diffusion across the blood-brain barrier (BBB). These experiments test the hypothesis that acute treatment with CAR after TBI can attenuate oxidative stress and BBB permeability associated with CAR's anti-edematous traits. Rats were divided into six groups and injured using Marmarou weight drop: Sham, TBI, TBI + Vehicle, TBI + CAR (100 and 200 mg/kg) and CAR200-naive treated rats. Intraperitoneal injection of vehicle or CAR was administered thirty minutes after TBI induction. 24 h post-injury, brain edema, BBB permeability, BBB-related protein levels, and oxidative capacity were measured. Data showed CAR 200 mg/kg treatment decreased brain edema and prevented BBB permeability. CAR200 decreased malondialdehyde (MDA) and reactive oxygen species (ROS) and increased superoxide dismutase (SOD) and total antioxidative capacity (T-AOC), indicating the mechanism of BBB protection is, in part, through antioxidant activity. Also, CAR 200 mg/kg treatment suppressed matrix metalloproteinase-9 (MMP-9) expression and increased ZO-1, occludin, and claudin-5 levels. These data indicate that CAR can promote antioxidant activity and decrease post-injury BBB permeability, further supporting CAR as a potential early therapeutic intervention that is inexpensive and more readily available worldwide. However, more experiments are required to determine CAR's long-term impact on TBI pathophysiology.
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Affiliation(s)
- Elham Abbasloo
- Institute of Basic and Clinical Physiology Sciences, Endocrinology and Metabolism Research Center, Kerman, Iran.
| | - Mohammad Khaksari
- Institute of Neuropharmacology, Physiology Research Center, Kerman University of Medical Sciences, Kerman, Iran
| | - Mojgan Sanjari
- Institute of Basic and Clinical Physiology Sciences, Endocrinology and Metabolism Research Center, Kerman, Iran
| | - Firas Kobeissy
- Department of Biochemistry and Molecular Genetics, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
| | - Theresa Currier Thomas
- College of Medicine-Phoenix, University of Arizona, Child Health, Phoenix, USA
- BARROW Neurological Institute at Phoenix Children's Hospital, Phoenix, USA
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4
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Gudkov SV, Burmistrov DE, Kondakova EV, Sarimov RM, Yarkov RS, Franceschi C, Vedunova MV. An emerging role of astrocytes in aging/neuroinflammation and gut-brain axis with consequences on sleep and sleep disorders. Ageing Res Rev 2023; 83:101775. [PMID: 36334910 DOI: 10.1016/j.arr.2022.101775] [Citation(s) in RCA: 16] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Revised: 10/05/2022] [Accepted: 10/30/2022] [Indexed: 11/18/2022]
Abstract
Understanding the role of astrocytes in the central nervous system has changed dramatically over the last decade. The accumulating findings indicate that glial cells are involved not only in the maintenance of metabolic and ionic homeostasis and in the implementation of trophic functions but also in cognitive functions and information processing in the brain. Currently, there are some controversies regarding the role of astrocytes in complex processes such as aging of the nervous system and the pathogenesis of age-related neurodegenerative diseases. Many findings confirm the important functional role of astrocytes in age-related brain changes, including sleep disturbance and the development of neurodegenerative diseases and particularly Alzheimer's disease. Until recent years, neurobiological research has focused mainly on neuron-glial interactions, in which individual astrocytes locally modulate neuronal activity and communication between neurons. The review considers the role of astrocytes in the physiology of sleep and as an important "player" in the development of neurodegenerative diseases. In addition, the features of the astrocytic network reorganization during aging are discussed.
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Affiliation(s)
- Sergey V Gudkov
- Prokhorov General Physics Institute of the Russian Academy of Sciences, 38 Vavilov str., 119991 Moscow, Russia; Institute of Biology and Biomedicine, Lobachevsky State University of Nizhny Novgorod, 23 Gagarin ave., 603022 Nizhny Novgorod, Russia.
| | - Dmitriy E Burmistrov
- Prokhorov General Physics Institute of the Russian Academy of Sciences, 38 Vavilov str., 119991 Moscow, Russia.
| | - Elena V Kondakova
- Institute of Biology and Biomedicine, Lobachevsky State University of Nizhny Novgorod, 23 Gagarin ave., 603022 Nizhny Novgorod, Russia.
| | - Ruslan M Sarimov
- Prokhorov General Physics Institute of the Russian Academy of Sciences, 38 Vavilov str., 119991 Moscow, Russia.
| | - Roman S Yarkov
- Institute of Biology and Biomedicine, Lobachevsky State University of Nizhny Novgorod, 23 Gagarin ave., 603022 Nizhny Novgorod, Russia.
| | - Claudio Franceschi
- Institute of Biology and Biomedicine, Lobachevsky State University of Nizhny Novgorod, 23 Gagarin ave., 603022 Nizhny Novgorod, Russia.
| | - Maria V Vedunova
- Institute of Biology and Biomedicine, Lobachevsky State University of Nizhny Novgorod, 23 Gagarin ave., 603022 Nizhny Novgorod, Russia.
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5
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Puvogel S, Alsema A, Kracht L, Webster MJ, Weickert CS, Sommer IEC, Eggen BJL. Single-nucleus RNA sequencing of midbrain blood-brain barrier cells in schizophrenia reveals subtle transcriptional changes with overall preservation of cellular proportions and phenotypes. Mol Psychiatry 2022; 27:4731-4740. [PMID: 36192459 PMCID: PMC9734060 DOI: 10.1038/s41380-022-01796-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 09/02/2022] [Accepted: 09/09/2022] [Indexed: 12/14/2022]
Abstract
The midbrain is an extensively studied brain region in schizophrenia, in view of its reported dopamine pathophysiology and neuroimmune changes associated with this disease. Besides the dopaminergic system, the midbrain contains other cell types that may be involved in schizophrenia pathophysiology. The neurovascular hypothesis of schizophrenia postulates that both the neurovasculature structure and the functioning of the blood-brain barrier (BBB) are compromised in schizophrenia. In the present study, potential alteration in the BBB of patients with schizophrenia was investigated by single-nucleus RNA sequencing of post-mortem midbrain tissue (15 schizophrenia cases and 14 matched controls). We did not identify changes in the relative abundance of the major BBB cell types, nor in the sub-populations, associated with schizophrenia. However, we identified 14 differentially expressed genes in the cells of the BBB in schizophrenia as compared to controls, including genes that have previously been related to schizophrenia, such as FOXP2 and PDE4D. These transcriptional changes were limited to the ependymal cells and pericytes, suggesting that the cells of the BBB are not broadly affected in schizophrenia.
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Affiliation(s)
- Sofía Puvogel
- Department of Biomedical Sciences of Cells and Systems, section Cognitive Neuroscience, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.
- Department of Biomedical Sciences of Cells and Systems, section Molecular Neurobiology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.
| | - Astrid Alsema
- Department of Biomedical Sciences of Cells and Systems, section Molecular Neurobiology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Laura Kracht
- Department of Biomedical Sciences of Cells and Systems, section Molecular Neurobiology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Maree J Webster
- Laboratory of Brain Research, Stanley Medical Research Institute, Rockville, MD, USA
| | - Cynthia Shannon Weickert
- Schizophrenia Research Laboratory, Neuroscience Research Australia, Sydney, NSW, Australia
- School of Psychiatry, University of New South Wales, Sydney, NSW, Australia
- Department of Neuroscience and Physiology, Upstate Medical University, Syracuse, NY, USA
| | - Iris E C Sommer
- Department of Biomedical Sciences of Cells and Systems, section Cognitive Neuroscience, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
- Department of Psychiatry, Brain Center Rudolf Magnus, University Medical Centre Utrecht, Utrecht, The Netherlands
| | - Bart J L Eggen
- Department of Biomedical Sciences of Cells and Systems, section Molecular Neurobiology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
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6
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Sastri KT, Gupta NV, M S, Chakraborty S, Kumar H, Chand P, Balamuralidhara V, Gowda D. Nanocarrier facilitated drug delivery to the brain through intranasal route: A promising approach to transcend bio-obstacles and alleviate neurodegenerative conditions. J Drug Deliv Sci Technol 2022. [DOI: 10.1016/j.jddst.2022.103656] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
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7
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Liu J, Feng X, Wang Y, Xia X, Zheng JC. Astrocytes: GABAceptive and GABAergic Cells in the Brain. Front Cell Neurosci 2022; 16:892497. [PMID: 35755777 PMCID: PMC9231434 DOI: 10.3389/fncel.2022.892497] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Accepted: 05/17/2022] [Indexed: 12/14/2022] Open
Abstract
Astrocytes, the most numerous glial cells in the brain, play an important role in preserving normal neural functions and mediating the pathogenesis of neurological disorders. Recent studies have shown that astrocytes are GABAceptive and GABAergic astrocytes express GABAA receptors, GABAB receptors, and GABA transporter proteins to capture and internalize GABA. GABAceptive astrocytes thus influence both inhibitory and excitatory neurotransmission by controlling the levels of extracellular GABA. Furthermore, astrocytes synthesize and release GABA to directly regulate brain functions. In this review, we highlight recent research progresses that support astrocytes as GABAceptive and GABAergic cells. We also summarize the roles of GABAceptive and GABAergic astrocytes that serve as an inhibitory node in the intercellular communication in the brain. Besides, we discuss future directions for further expanding our knowledge on the GABAceptive and GABAergic astrocyte signaling.
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Affiliation(s)
- Jianhui Liu
- Department of Anesthesiology, Tongji Hospital affiliated to Tongji University School of Medicine, Shanghai, China
| | - Xuanran Feng
- Department of Anesthesiology, Tongji Hospital affiliated to Tongji University School of Medicine, Shanghai, China
| | - Yi Wang
- Translational Research Center, Shanghai Yangzhi Rehabilitation Hospital affiliated to Tongji University School of Medicine, Shanghai, China
| | - Xiaohuan Xia
- Department of Anesthesiology, Tongji Hospital affiliated to Tongji University School of Medicine, Shanghai, China.,Center for Translational Neurodegeneration and Regenerative Therapy, Tongji Hospital affiliated to Tongji University School of Medicine, Shanghai, China.,Shanghai Frontiers Science Center of Nanocatalytic Medicine, Shanghai, China.,Translational Research Institute of Brain and Brain-Like Intelligence, Shanghai Fourth People's Hospital affiliated to Tongji University School of Medicine, Shanghai, China
| | - Jialin C Zheng
- Department of Anesthesiology, Tongji Hospital affiliated to Tongji University School of Medicine, Shanghai, China.,Center for Translational Neurodegeneration and Regenerative Therapy, Tongji Hospital affiliated to Tongji University School of Medicine, Shanghai, China.,Shanghai Frontiers Science Center of Nanocatalytic Medicine, Shanghai, China.,Translational Research Institute of Brain and Brain-Like Intelligence, Shanghai Fourth People's Hospital affiliated to Tongji University School of Medicine, Shanghai, China.,Collaborative Innovation Center for Brain Science, Tongji University, Shanghai, China
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8
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Zhao Y, Gan L, Ren L, Lin Y, Ma C, Lin X. Factors influencing the blood-brain barrier permeability. Brain Res 2022; 1788:147937. [PMID: 35568085 DOI: 10.1016/j.brainres.2022.147937] [Citation(s) in RCA: 74] [Impact Index Per Article: 37.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Revised: 04/28/2022] [Accepted: 05/03/2022] [Indexed: 12/14/2022]
Abstract
The blood-brain barrier (BBB) is a dynamic structure that protects the brain from harmful blood-borne, endogenous and exogenous substances and maintains the homeostatic microenvironment. All constituent cell types play indispensable roles in the BBB's integrity, and other structural BBB components, such as tight junction proteins, adherens junctions, and junctional proteins, can control the barrier permeability. Regarding the need to exchange nutrients and toxic materials, solute carriers, ATP-binding case families, and ion transporter, as well as transcytosis regulate the influx and efflux transport, while the difference in localisation and expression can contribute to functional differences in transport properties. Numerous chemical mediators and other factors such as non-physicochemical factors have been identified to alter BBB permeability by mediating the structural components and barrier function, because of the close relationship with inflammation. In this review, we highlight recently gained mechanistic insights into the maintenance and disruption of the BBB. A better understanding of the factors influencing BBB permeability could contribute to supporting promising potential therapeutic targets for protecting the BBB and the delivery of central nervous system drugs via BBB permeability interventions under pathological conditions.
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Affiliation(s)
- Yibin Zhao
- The Third Clinical Medical College, Zhejiang Chinese Medical University, Hangzhou, China; Department of Neurobiology and Acupuncture Research, Zhejiang Chinese Medical University, Hangzhou, China
| | - Lin Gan
- The Third Clinical Medical College, Zhejiang Chinese Medical University, Hangzhou, China; Department of Neurobiology and Acupuncture Research, Zhejiang Chinese Medical University, Hangzhou, China
| | - Li Ren
- The Third Clinical Medical College, Zhejiang Chinese Medical University, Hangzhou, China; Department of Neurobiology and Acupuncture Research, Zhejiang Chinese Medical University, Hangzhou, China
| | - Yubo Lin
- The Third Clinical Medical College, Zhejiang Chinese Medical University, Hangzhou, China; Department of Neurobiology and Acupuncture Research, Zhejiang Chinese Medical University, Hangzhou, China
| | - Congcong Ma
- The Third Clinical Medical College, Zhejiang Chinese Medical University, Hangzhou, China; Department of Neurobiology and Acupuncture Research, Zhejiang Chinese Medical University, Hangzhou, China
| | - Xianming Lin
- The Third Clinical Medical College, Zhejiang Chinese Medical University, Hangzhou, China; Department of Neurobiology and Acupuncture Research, Zhejiang Chinese Medical University, Hangzhou, China.
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9
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Taylor X, Cisternas P, Jury N, Martinez P, Huang X, You Y, Redding-Ochoa J, Vidal R, Zhang J, Troncoso J, Lasagna-Reeves CA. Activated endothelial cells induce a distinct type of astrocytic reactivity. Commun Biol 2022; 5:282. [PMID: 35351973 PMCID: PMC8964703 DOI: 10.1038/s42003-022-03237-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Accepted: 03/09/2022] [Indexed: 12/13/2022] Open
Abstract
Reactive astrogliosis is a universal response of astrocytes to abnormal events and injuries. Studies have shown that proinflammatory microglia can polarize astrocytes (designated A1 astrocytes) toward a neurotoxic phenotype characterized by increased Complement Component 3 (C3) expression. It is still unclear if inflammatory stimuli from other cell types may also be capable of inducing a subset of C3+ neurotoxic astrocytes. Here, we show that a subtype of C3+ neurotoxic astrocytes is induced by activated endothelial cells that is distinct from astrocytes activated by microglia. Furthermore, we show that endothelial-induced astrocytes have upregulated expression of A1 astrocytic genes and exhibit a distinctive extracellular matrix remodeling profile. Finally, we demonstrate that endothelial-induced astrocytes are Decorin-positive and are associated with vascular amyloid deposits but not parenchymal amyloid plaques in mouse models and AD/CAA patients. These findings demonstrate the existence of potentially extensive and subtle functional diversity of C3+-reactive astrocytes. Injured endothelial cells are shown to induce an A1 phenotype in astrocytes, characterized by a genetic signature associated with extracellular matrix remodeling factors (e.g. decorin and vascular Aß deposits).
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Affiliation(s)
- Xavier Taylor
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, 46202, USA.,Department of Anatomy, Cell Biology & Physiology, Indiana University School of Medicine, Indianapolis, IN, 46202, USA.,Neuroscience Discovery, Lilly Research Laboratories, Eli Lilly & Co, Lilly Corporate Center, Indianapolis, IN, 46225, USA
| | - Pablo Cisternas
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, 46202, USA.,Department of Anatomy, Cell Biology & Physiology, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
| | - Nur Jury
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, 46202, USA.,Department of Anatomy, Cell Biology & Physiology, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
| | - Pablo Martinez
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, 46202, USA.,Department of Anatomy, Cell Biology & Physiology, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
| | - Xiaoqing Huang
- Department of Biostatistics and Health Data Science, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
| | - Yanwen You
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, 46202, USA.,Department of Anatomy, Cell Biology & Physiology, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
| | - Javier Redding-Ochoa
- Department of Pathology, School of Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Ruben Vidal
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, 46202, USA.,Department of Pathology and Laboratory Medicine, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
| | - Jie Zhang
- Department of Biostatistics and Health Data Science, Indiana University School of Medicine, Indianapolis, IN, 46202, USA.,Center for Computational Biology and Bioinformatics, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Juan Troncoso
- Department of Pathology, School of Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Cristian A Lasagna-Reeves
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, 46202, USA. .,Department of Anatomy, Cell Biology & Physiology, Indiana University School of Medicine, Indianapolis, IN, 46202, USA. .,Center for Computational Biology and Bioinformatics, Indiana University School of Medicine, Indianapolis, IN, USA.
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10
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Yu J, Huang Y, Quan C, Zhou L, ZhangBao J, Wu K, Zong Y, Zhou X, Wang M. Alterations in the Retinal Vascular Network and Structure in MOG Antibody-Associated Disease: An Optical Coherence Tomography Angiography Study. J Neuroophthalmol 2021; 41:e424-e432. [PMID: 33136671 DOI: 10.1097/wno.0000000000001116] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND To determine retinal vessel density in patients with myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD). METHODS Twenty-five patients with MOGAD and 20 healthy participants were enrolled. Patients with MOGAD were divided into myelin oligodendrocyte glycoprotein antibody (MOG-Ab)-positive eyes with a history of optic neuritis (ON; MOG-Ab-ON+ group) or without a history of ON (MOG-Ab-ON- group). Visual function, retinal vessel densities, and thickness were measured. RESULTS The retinal nerve fiber layer, parafoveal ganglion cell and inner plexiform layers, and vessel densities in the peripapillary and parafoveal areas were significantly decreased in the MOG-Ab-ON+ eyes compared with healthy eyes and MOG-Ab-ON- eyes (all P < 0.05). An increasing number of ON episodes was associated with greater decreases in these variables (all P < 0.05). Visual field mean deviation was not significantly decreased in patients with a history of 1 or 2 episodes of ON, although the relative decreases in retinal nerve fiber layer thickness, parafoveal ganglion cell and inner plexiform layer thickness, peripapillary vessel density, and parafoveal vessel density reached 33.1%, 23.2%, 17.0%, and 11.5% (all P < 0.05), respectively, in eyes with 2 episodes of ON. The mean deviation was significantly correlated with peripapillary vessel density (P < 0.05) after adjustment for other variables. Best-corrected visual acuity was not significantly correlated with optical coherence tomography variables (all P > 0.05). CONCLUSIONS MOG-Ab-associated ON was associated with significant decreases in retinal structure and vessel density, without significant deteriorations in visual function. The peripapillary vessel density might predict the visual outcomes in patients with MOG-Ab-associated ON.
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Affiliation(s)
- Jian Yu
- Department of Ophthalmology and Vision Science (JY, YH, KW, YZ, XZ, MW), Eye and ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, China ; Key Laboratory of Myopia of State Health Ministry (JY, YH, KW, YZ, XZ, MW), and Key Laboratory of Visual Impairment and Restoration of Shanghai, Shanghai, China ; NHC Key Laboratory of Myopia (Fudan University) (JY, YH, KW, YZ, XZ, MW), Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China ; Department of Ophthalmology (YH), Kiang Wu Hospital, Macau Special Administration Region, China ; and Department of Neurology (LZ, JZB, CQ), Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, China
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11
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Aryal R, Patabendige A. Blood-brain barrier disruption in atrial fibrillation: a potential contributor to the increased risk of dementia and worsening of stroke outcomes? Open Biol 2021; 11:200396. [PMID: 33878948 PMCID: PMC8059575 DOI: 10.1098/rsob.200396] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Atrial fibrillation (AF) has become one of the most significant health problems worldwide, warranting urgent answers to currently pending questions on the effects of AF on brain function. Recent evidence has emerged to show an association between AF and an increased risk of developing dementia and worsening of stroke outcomes. A healthy brain is protected by the blood–brain barrier (BBB), which is formed by the endothelial cells that line cerebral capillaries. These endothelial cells are continuously exposed to shear stress (the frictional force generated by blood flow), which affects endothelial cell structure and function. Flow disturbances as experienced during AF can disrupt the BBB and leave the brain vulnerable to damage. Investigating the plausible mechanisms in detail, linking AF to cerebrovascular damage is difficult in humans, leading to paucity of available clinical data. Here, we discuss the available evidence for BBB disruption during AF due to altered cerebral blood flow, and how this may contribute to an increased risk of dementia and worsening of stroke outcomes.
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Affiliation(s)
- Ritambhara Aryal
- Brain Barriers Group, School of Biomedical Sciences and Pharmacy, The University of Newcastle, Callaghan, NSW 2308, Australia.,Brain and Mental Health Research Programme, Hunter Medical Research Institute, Newcastle, Australia
| | - Adjanie Patabendige
- Brain Barriers Group, School of Biomedical Sciences and Pharmacy, The University of Newcastle, Callaghan, NSW 2308, Australia.,Brain and Mental Health Research Programme, Hunter Medical Research Institute, Newcastle, Australia.,Institute of Infection and Global Health, University of Liverpool, Liverpool, UK
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12
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Hwang SN, Lee JS, Seo K, Lee H. Astrocytic Regulation of Neural Circuits Underlying Behaviors. Cells 2021; 10:cells10020296. [PMID: 33535587 PMCID: PMC7912785 DOI: 10.3390/cells10020296] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 01/23/2021] [Accepted: 01/29/2021] [Indexed: 02/07/2023] Open
Abstract
Astrocytes, characterized by a satellite-like morphology, are the most abundant type of glia in the central nervous system. Their main functions have been thought to be limited to providing homeostatic support for neurons, but recent studies have revealed that astrocytes actually actively interact with local neural circuits and play a crucial role in information processing and generating physiological and behavioral responses. Here, we review the emerging roles of astrocytes in many brain regions, particularly by focusing on intracellular changes in astrocytes and their interactions with neurons at the molecular and neural circuit levels.
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Affiliation(s)
- Sun-Nyoung Hwang
- Convergence Research Advanced Centre for Olfaction, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Korea;
| | - Jae Seung Lee
- Department of Brain and Cognitive Sciences, DGIST, Daegu 42988, Korea; (J.S.L.); (K.S.)
| | - Kain Seo
- Department of Brain and Cognitive Sciences, DGIST, Daegu 42988, Korea; (J.S.L.); (K.S.)
| | - Hyosang Lee
- Convergence Research Advanced Centre for Olfaction, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Korea;
- Department of Brain and Cognitive Sciences, DGIST, Daegu 42988, Korea; (J.S.L.); (K.S.)
- Korea Brain Research Institute (KBRI), Daegu 41062, Korea
- Correspondence: ; Tel.: +82-53-785-6147
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13
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Mao XW, Nishiyama NC, Byrum SD, Stanbouly S, Jones T, Holley J, Sridharan V, Boerma M, Tackett AJ, Willey JS, Pecaut MJ, Delp MD. Spaceflight induces oxidative damage to blood-brain barrier integrity in a mouse model. FASEB J 2020; 34:15516-15530. [PMID: 32981077 PMCID: PMC8191453 DOI: 10.1096/fj.202001754r] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 09/10/2020] [Accepted: 09/11/2020] [Indexed: 12/18/2022]
Abstract
Many factors contribute to the health risks encountered by astronauts on missions outside Earth's atmosphere. Spaceflight-induced potential adverse neurovascular damage and late neurodegeneration are a chief concern. The goal of the present study was to characterize the effects of spaceflight on oxidative damage in the mouse brain and its impact on blood-brain barrier (BBB) integrity. Ten-week-old male C57BL/6 mice were launched to the International Space Station (ISS) for 35 days as part of Space-X 12 mission. Ground control (GC) mice were maintained on Earth in flight hardware cages. Within 38 ± 4 hours after returning from the ISS, mice were euthanized and brain tissues were collected for analysis. Quantitative assessment of brain tissue demonstrated that spaceflight caused an up to 2.2-fold increase in apoptosis in the hippocampus compared to the control group. Immunohistochemical analysis of the mouse brain revealed an increased expression of aquaporin4 (AQP4) in the flight hippocampus compared to the controls. There was also a significant increase in the expression of platelet endothelial cell adhesion molecule-1 (PECAM-1) and a decrease in the expression of the BBB-related tight junction protein, Zonula occludens-1 (ZO-1). These results indicate a disturbance of BBB integrity. Quantitative proteomic analysis showed significant alterations in pathways responsible for neurovascular integrity, mitochondrial function, neuronal structure, protein/organelle transport, and metabolism in the brain after spaceflight. Changes in pathways associated with adhesion and molecular remodeling were also documented. These data indicate that long-term spaceflight may have pathological and functional consequences associated with neurovascular damage and late neurodegeneration.
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Affiliation(s)
- Xiao W Mao
- Department of Basic Sciences, Division of Biomedical Engineering Sciences (BMES), Loma Linda University School of Medicine and Medical Center, Loma Linda, CA, USA
| | - Nina C Nishiyama
- Department of Basic Sciences, Division of Biomedical Engineering Sciences (BMES), Loma Linda University School of Medicine and Medical Center, Loma Linda, CA, USA
| | - Stephanie D Byrum
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, AR, USA
- Arkansas Children's Research Institute, Little Rock, AR, USA
| | - Seta Stanbouly
- Department of Basic Sciences, Division of Biomedical Engineering Sciences (BMES), Loma Linda University School of Medicine and Medical Center, Loma Linda, CA, USA
| | - Tamako Jones
- Department of Basic Sciences, Division of Biomedical Engineering Sciences (BMES), Loma Linda University School of Medicine and Medical Center, Loma Linda, CA, USA
| | - Jacob Holley
- Department of Basic Sciences, Division of Biomedical Engineering Sciences (BMES), Loma Linda University School of Medicine and Medical Center, Loma Linda, CA, USA
| | - Vijayalakshmi Sridharan
- Division of Radiation Health, Department of Pharmaceutical Sciences, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Marjan Boerma
- Division of Radiation Health, Department of Pharmaceutical Sciences, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Alan J Tackett
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, AR, USA
- Arkansas Children's Research Institute, Little Rock, AR, USA
| | - Jeffrey S Willey
- Department of Radiation Oncology, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - Michael J Pecaut
- Department of Basic Sciences, Division of Biomedical Engineering Sciences (BMES), Loma Linda University School of Medicine and Medical Center, Loma Linda, CA, USA
| | - Michael D Delp
- Department of Nutrition, Food and Exercise Sciences, Florida State University, Tallahassee, FL, USA
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14
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Freitas-Andrade M, Raman-Nair J, Lacoste B. Structural and Functional Remodeling of the Brain Vasculature Following Stroke. Front Physiol 2020; 11:948. [PMID: 32848875 PMCID: PMC7433746 DOI: 10.3389/fphys.2020.00948] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Accepted: 07/14/2020] [Indexed: 12/12/2022] Open
Abstract
Maintenance of cerebral blood vessel integrity and regulation of cerebral blood flow ensure proper brain function. The adult human brain represents only a small portion of the body mass, yet about a quarter of the cardiac output is dedicated to energy consumption by brain cells at rest. Due to a low capacity to store energy, brain health is heavily reliant on a steady supply of oxygen and nutrients from the bloodstream, and is thus particularly vulnerable to stroke. Stroke is a leading cause of disability and mortality worldwide. By transiently or permanently limiting tissue perfusion, stroke alters vascular integrity and function, compromising brain homeostasis and leading to widespread consequences from early-onset motor deficits to long-term cognitive decline. While numerous lines of investigation have been undertaken to develop new pharmacological therapies for stroke, only few advances have been made and most clinical trials have failed. Overall, our understanding of the acute and chronic vascular responses to stroke is insufficient, yet a better comprehension of cerebrovascular remodeling following stroke is an essential prerequisite for developing novel therapeutic options. In this review, we present a comprehensive update on post-stroke cerebrovascular remodeling, an important and growing field in neuroscience, by discussing cellular and molecular mechanisms involved, sex differences, limitations of preclinical research design and future directions.
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Affiliation(s)
| | - Joanna Raman-Nair
- Neuroscience Program, Ottawa Hospital Research Institute, Ottawa, ON, Canada
| | - Baptiste Lacoste
- Neuroscience Program, Ottawa Hospital Research Institute, Ottawa, ON, Canada
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada
- Brain and Mind Research Institute, University of Ottawa, Ottawa, ON, Canada
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15
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Chen BS, Lee HC, Lee KM, Gong YN, Shih SR. Enterovirus and Encephalitis. Front Microbiol 2020; 11:261. [PMID: 32153545 PMCID: PMC7044131 DOI: 10.3389/fmicb.2020.00261] [Citation(s) in RCA: 65] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Accepted: 02/04/2020] [Indexed: 12/24/2022] Open
Abstract
Enterovirus-induced infection of the central nervous system (CNS) results in acute inflammation of the brain (encephalitis) and constitutes a significant global burden to human health. These viruses are thought to be highly cytolytic, therefore normal brain function could be greatly compromised following enteroviral infection of the CNS. A further layer of complexity is added by evidence showing that some enteroviruses may establish a persistent infection within the CNS and eventually lead to pathogenesis of certain neurodegenerative disorders. Interestingly, enterovirus encephalitis is particularly common among young children, suggesting a potential causal link between the development of the neuroimmune system and enteroviral neuroinvasion. Although the CNS involvement in enterovirus infections is a relatively rare complication, it represents a serious underlying cause of mortality. Here we review a selection of enteroviruses that infect the CNS and discuss recent advances in the characterization of these enteroviruses with regard to their routes of CNS infection, tropism, virulence, and immune responses.
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Affiliation(s)
- Bo-Shiun Chen
- Research Center for Emerging Viral Infections, College of Medicine, Chang Gung University, Taoyuan, Taiwan.,Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Augusta University, Augusta, GA, United States
| | - Hou-Chen Lee
- Research Center for Emerging Viral Infections, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Kuo-Ming Lee
- Research Center for Emerging Viral Infections, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Yu-Nong Gong
- Research Center for Emerging Viral Infections, College of Medicine, Chang Gung University, Taoyuan, Taiwan.,Department of Laboratory Medicine, Linkou Chang Gung Memorial Hospital, Taoyuan, Taiwan
| | - Shin-Ru Shih
- Research Center for Emerging Viral Infections, College of Medicine, Chang Gung University, Taoyuan, Taiwan.,Department of Laboratory Medicine, Linkou Chang Gung Memorial Hospital, Taoyuan, Taiwan.,Department of Medical Biotechnology and Laboratory Science, College of Medicine, Chang Gung University, Taoyuan, Taiwan.,Research Center for Chinese Herbal Medicine, College of Human Ecology, Chang Gung University of Science and Technology, Taoyuan, Taiwan.,Research Center for Food and Cosmetic Safety, College of Human Ecology, Chang Gung University of Science and Technology, Taoyuan, Taiwan.,Graduate Institute of Health Industry Technology, College of Human Ecology, Chang Gung University of Science and Technology, Taoyuan, Taiwan
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16
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Wood TE, Barry J, Yang Z, Cepeda C, Levine MS, Gray M. Mutant huntingtin reduction in astrocytes slows disease progression in the BACHD conditional Huntington's disease mouse model. Hum Mol Genet 2019; 28:487-500. [PMID: 30312396 DOI: 10.1093/hmg/ddy363] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Accepted: 10/09/2018] [Indexed: 01/08/2023] Open
Abstract
Neuronal and non-neuronal cells express the huntingtin (HTT) protein, yet neurodegeneration in Huntington's disease (HD) is largely selective, affecting most prominently striatal medium spiny neurons and cortical pyramidal neurons. Selective toxicity of full-length human mutant HTT (fl-mHTT) may be due in part to its expression in non-neuronal cells. While studies suggest neuronal-glial interactions are important in HD and fl-mHTT is expressed in astrocytes, it has not been determined whether the expression of fl-mHTT in astrocytes is necessary for HD pathogenesis. To directly assess the necessity of fl-mHTT in astrocytes for HD pathogenesis, we used a mouse genetic approach and bred the conditional mHTT-expressing BACHD mouse model with GFAP-CreERT2 mice. We show that GFAP-CreERT2 expression in these mice is highly selective for astrocytes, and we are able to significantly reduce the expression of fl-mHTT protein in the striatum and cortex of BACHD/GFAP-CreERT2-tam mice. We performed behavioral, electrophysiological and neuropathological analyses of BACHD and BACHD/GFAP-CreERT2-tam mice. Behavioral analyses of BACHD/GFAP-CreERT2-tam mice demonstrate significant improvements in motor and psychiatric-like phenotypes. We observe improvements in neuropathological and electrophysiological phenotypes in BACHD/GFAP-CreERT2-tam mice compared to BACHD mice. We observed a restoration of the normal level αB-crystallin in the striatum of the BACHD/GFAP-CreERT2 mice, indicating a cell autonomous effect of mHTT on its expression. Taken together, this work indicates that astrocytes are important contributors to the progression of the behavioral and neuropathological phenotypes observed in HD.
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Affiliation(s)
- Tara E Wood
- Center for Neurodegeneration and Experimental Therapeutics, Department of Neurology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Joshua Barry
- Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA
| | - Zhenquin Yang
- Center for Neurodegeneration and Experimental Therapeutics, Department of Neurology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Carlos Cepeda
- Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA
| | - Michael S Levine
- Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA
| | - Michelle Gray
- Center for Neurodegeneration and Experimental Therapeutics, Department of Neurology, University of Alabama at Birmingham, Birmingham, AL, USA
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17
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Kunze R, Marti HH. Angioneurins - Key regulators of blood-brain barrier integrity during hypoxic and ischemic brain injury. Prog Neurobiol 2019; 178:101611. [PMID: 30970273 DOI: 10.1016/j.pneurobio.2019.03.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Accepted: 03/29/2019] [Indexed: 12/14/2022]
Abstract
The loss of blood-brain barrier (BBB) integrity leading to vasogenic edema and brain swelling is a common feature of hypoxic/ischemic brain diseases such as stroke, but is also central to the etiology of other CNS disorders. In the past decades, numerous proteins, belonging to the family of angioneurins, have gained increasing attention as potential therapeutic targets for ischemic stroke, but also other CNS diseases attributed to BBB dysfunction. Angioneurins encompass mediators that affect both neuronal and vascular function. Recently, increasing evidence has been accumulated that certain angioneurins critically determine disease progression and outcome in stroke among others through multifaceted effects on the compromised BBB. Here, we will give a concise overview about the family of angioneurins. We further describe the most important cellular and molecular components that contribute to structural integrity and low permeability of the BBB under steady-state conditions. We then discuss BBB alterations in ischemic stroke, and highlight underlying cellular and molecular mechanisms. For the most prominent angioneurin family members including vascular endothelial growth factors, angiopoietins, platelet-derived growth factors and erythropoietin, we will summarize current scientific literature from experimental studies in animal models, and if available from clinical trials, on the following points: (i) spatiotemporal expression of these factors in the healthy and hypoxic/ischemic CNS, (ii) impact of loss- or gain-of-function during cerebral hypoxia/ischemia for BBB integrity and beyond, and (iii) potential underlying molecular mechanisms. Moreover, we will highlight novel therapeutic strategies based on the activation of endogenous angioneurins that might improve BBB dysfuntion during ischemic stroke.
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Affiliation(s)
- Reiner Kunze
- Institute of Physiology and Pathophysiology, Heidelberg University, Germany.
| | - Hugo H Marti
- Institute of Physiology and Pathophysiology, Heidelberg University, Germany
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18
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Ashhad S, Narayanan R. Stores, Channels, Glue, and Trees: Active Glial and Active Dendritic Physiology. Mol Neurobiol 2019; 56:2278-2299. [PMID: 30014322 PMCID: PMC6394607 DOI: 10.1007/s12035-018-1223-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2017] [Accepted: 07/03/2018] [Indexed: 02/07/2023]
Abstract
Glial cells and neuronal dendrites were historically assumed to be passive structures that play only supportive physiological roles, with no active contribution to information processing in the central nervous system. Research spanning the past few decades has clearly established this assumption to be far from physiological realities. Whereas the discovery of active channel conductances and their localized plasticity was the turning point for dendritic structures, the demonstration that glial cells release transmitter molecules and communicate across the neuroglia syncytium through calcium wave propagation constituted path-breaking discoveries for glial cell physiology. An additional commonality between these two structures is the ability of calcium stores within their endoplasmic reticulum (ER) to support active propagation of calcium waves, which play crucial roles in the spatiotemporal integration of information within and across cells. Although there have been several demonstrations of regulatory roles of glial cells and dendritic structures in achieving common physiological goals such as information propagation and adaptability through plasticity, studies assessing physiological interactions between these two active structures have been few and far. This lacuna is especially striking given the strong connectivity that is known to exist between these two structures through several complex and tightly intercoupled mechanisms that also recruit their respective ER structures. In this review, we present brief overviews of the parallel literatures on active dendrites and active glial physiology and make a strong case for future studies to directly assess the strong interactions between these two structures in regulating physiology and pathophysiology of the brain.
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Affiliation(s)
- Sufyan Ashhad
- Department of Neurobiology, University of California at Los Angeles, Los Angeles, CA, 90095, USA
| | - Rishikesh Narayanan
- Cellular Neurophysiology Laboratory, Molecular Biophysics Unit, Indian Institute of Science, Bangalore, 560012, India.
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19
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Calvetti D, Prezioso J, Somersalo E. Estimating hemodynamic stimulus and blood vessel compliance from cerebral blood flow data. J Theor Biol 2019; 460:243-261. [PMID: 30312691 PMCID: PMC8201967 DOI: 10.1016/j.jtbi.2018.10.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2018] [Revised: 09/14/2018] [Accepted: 10/04/2018] [Indexed: 11/23/2022]
Abstract
Several key brain imaging modalities that are intended for retrieving information about neuronal activity in brain, the BOLD fMRI as a foremost example, rely on the assumption that elevated neuronal activity elicits spatiotemporally well localized increase of the oxygenated blood volume, which in turn can be monitored non-invasively. The details of the signaling in the neurovascular unit during hyperemia are still not completely understood, and remain a topic of active research, requiring good mathematical models that are able to couple the different aspects of the signaling event. In this work, the question of estimating the hemodynamic stimulus function from cerebral blood flow data is addressed. In the present model, the hemodynamic stimulus is a non-specific signal from the electrophysiological and metabolic complex that controls the compliance of the blood vessels, leading to a vasodilation and thereby to an increase of blood flow. The underlying model is based on earlier literature, and it is further developed in this article for the needs of the inverse problem, which is solved using hierarchical Bayesian methodology, addressing also the poorly known model parameters.
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Affiliation(s)
- D Calvetti
- Department of Mathematics, Applied Mathematics and Statistics, Case Western Reserve University, Cleveland, OH, USA.
| | - J Prezioso
- Department of Mathematics, Applied Mathematics and Statistics, Case Western Reserve University, Cleveland, OH, USA.
| | - E Somersalo
- Department of Mathematics, Applied Mathematics and Statistics, Case Western Reserve University, Cleveland, OH, USA.
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20
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Rakers C, Schleif M, Blank N, Matušková H, Ulas T, Händler K, Torres SV, Schumacher T, Tai K, Schultze JL, Jackson WS, Petzold GC. Stroke target identification guided by astrocyte transcriptome analysis. Glia 2018; 67:619-633. [DOI: 10.1002/glia.23544] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Revised: 08/28/2018] [Accepted: 08/29/2018] [Indexed: 12/19/2022]
Affiliation(s)
- Cordula Rakers
- German Center for Neurodegenerative Diseases (DZNE); Bonn Germany
| | - Melvin Schleif
- German Center for Neurodegenerative Diseases (DZNE); Bonn Germany
| | - Nelli Blank
- German Center for Neurodegenerative Diseases (DZNE); Bonn Germany
| | - Hana Matušková
- German Center for Neurodegenerative Diseases (DZNE); Bonn Germany
- Department of Neurology; University Hospital Bonn; Bonn Germany
| | - Thomas Ulas
- Genomics and Immunoregulation; LIMES-Institute, University of Bonn; Germany
| | - Kristian Händler
- Genomics and Immunoregulation; LIMES-Institute, University of Bonn; Germany
| | | | - Toni Schumacher
- German Center for Neurodegenerative Diseases (DZNE); Bonn Germany
| | - Khalid Tai
- German Center for Neurodegenerative Diseases (DZNE); Bonn Germany
| | - Joachim L. Schultze
- German Center for Neurodegenerative Diseases (DZNE); Bonn Germany
- Genomics and Immunoregulation; LIMES-Institute, University of Bonn; Germany
| | | | - Gabor C. Petzold
- German Center for Neurodegenerative Diseases (DZNE); Bonn Germany
- Department of Neurology; University Hospital Bonn; Bonn Germany
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21
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Cozzolino O, Marchese M, Trovato F, Pracucci E, Ratto GM, Buzzi MG, Sicca F, Santorelli FM. Understanding Spreading Depression from Headache to Sudden Unexpected Death. Front Neurol 2018; 9:19. [PMID: 29449828 PMCID: PMC5799941 DOI: 10.3389/fneur.2018.00019] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Accepted: 01/11/2018] [Indexed: 01/03/2023] Open
Abstract
Spreading depression (SD) is a neurophysiological phenomenon characterized by abrupt changes in intracellular ion gradients and sustained depolarization of neurons. It leads to loss of electrical activity, changes in the synaptic architecture, and an altered vascular response. Although SD is often described as a unique phenomenon with homogeneous characteristics, it may be strongly affected by the particular triggering event and by genetic background. Furthermore, SD may contribute differently to the pathogenesis of widely heterogeneous clinical conditions. Indeed, clinical disorders related to SD vary in their presentation and severity, ranging from benign headache conditions (migraine syndromes) to severely disabling events, such as cerebral ischemia, or even death in people with epilepsy. Although the characteristics and mechanisms of SD have been dissected using a variety of approaches, ranging from cells to human models, this phenomenon remains only partially understood because of its complexity and the difficulty of obtaining direct experimental data. Currently, clinical monitoring of SD is limited to patients who require neurosurgical interventions and the placement of subdural electrode strips. Significantly, SD events recorded in humans display electrophysiological features that are essentially the same as those observed in animal models. Further research using existing and new experimental models of SD may allow a better understanding of its core mechanisms, and of their differences in different clinical conditions, fostering opportunities to identify and develop targeted therapies for SD-related disorders and their worst consequences.
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Affiliation(s)
- Olga Cozzolino
- NEST, Istituto Nanoscienze CNR and Scuola Normale Superiore, Pisa, Italy
| | - Maria Marchese
- Molecular Medicine and Clinical Neurophysiology Laboratories, Department of Developmental Neuroscience, IRCCS Fondazione Stella Maris, Pisa, Italy
| | - Francesco Trovato
- NEST, Istituto Nanoscienze CNR and Scuola Normale Superiore, Pisa, Italy
| | - Enrico Pracucci
- NEST, Istituto Nanoscienze CNR and Scuola Normale Superiore, Pisa, Italy
| | - Gian Michele Ratto
- NEST, Istituto Nanoscienze CNR and Scuola Normale Superiore, Pisa, Italy
| | | | - Federico Sicca
- Molecular Medicine and Clinical Neurophysiology Laboratories, Department of Developmental Neuroscience, IRCCS Fondazione Stella Maris, Pisa, Italy
| | - Filippo M Santorelli
- Molecular Medicine and Clinical Neurophysiology Laboratories, Department of Developmental Neuroscience, IRCCS Fondazione Stella Maris, Pisa, Italy
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22
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Abstract
In the brain, the astrocentric view has increasingly changed in the past few years. The classical and old view of astrocytes as "just supporting cells" has assigned these cells some functions to help neurons maintain their homeostasis. This neuronal supportive function of astrocytes includes maintenance of ion and extracellular pH equilibrium, neuroendocrine signaling, metabolic support, clearance of glutamate and other neurotransmitters, and antioxidant protection. However, recent findings have shed some light on the new roles, some controversial though, performed by astrocytes that might change our view about the central nervous system functioning. Since astrocytes are important for neuronal survival, it is a potential approach to favor astrocytic functions in order to improve the outcome. Such translational strategies may include the use of genetically targeted proteins, and/or pharmacological therapies by administering androgens and estrogens, which have shown promising results in vitro and in vivo models. It is noteworthy that successful strategies reviewed in here shall be extrapolated to human subjects, and this is probably the next step we should move on.
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Affiliation(s)
- George E Barreto
- Departamento de Nutrición y Bioquímica, Facultad de Ciencias, Pontificia Universidad Javeriana, Bogotá D.C., Colombia.
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23
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Li H, Bui BV, Cull G, Wang F, Wang L. Glial Cell Contribution to Basal Vessel Diameter and Pressure-Initiated Vascular Responses in Rat Retina. Invest Ophthalmol Vis Sci 2017; 58:1-8. [PMID: 28055098 PMCID: PMC5225997 DOI: 10.1167/iovs.16-20804] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose The purpose of this study was to test the hypothesis that retinal glial cells modify basal vessel diameter and pressure-initiated vascular regulation in rat retina. Methods In rats, L-2-aminoadipic acid (LAA, 10 nM) was intravitreally injected to inhibit glial cell activity. Twenty-four hours following injection, retinal glial intracellular calcium (Ca2+) was labeled with the fluorescent calcium indicator Fluo-4/AM (F4, 1 mM). At 110 minutes after injection, intraocular pressure (IOP) was elevated from 20 to 50 mm Hg. Prior to and during IOP elevation, Ca2+ and retinal vessel diameter were assessed using a spectral-domain optical coherence tomography/confocal scanning laser ophthalmoscope. Dynamic changes in Ca2+ and diameter from IOP elevation were quantified. The response in LAA-treated eyes was compared with vehicle treated control eyes. Results L-2-Aminoadipic acid treatment significantly reduced F4-positive cells in the retina (LAA, 16 ± 20 vs. control, 55 ± 37 cells/mm2; P = 0.02). Twenty-four hours following LAA treatment, basal venous diameter was increased from 38.9 ± 3.9 to 51.8 ± 6.4 μm (P < 0.0001, n = 20), whereas arterial diameter was unchanged (from 30.3 ± 3.5 to 30.7 ± 2.8 μm; P = 0.64). In response to IOP elevation, LAA-treated eyes showed a smaller increase in glial cell Ca2+ around both arteries and veins in comparison with control (P < 0.001 for both). There was also significantly greater IOP-induced vasoconstriction in both vessel types (P = 0.05 and P = 0.02, respectively; n = 6 each). Conclusions The results suggest that glial cells can modulate basal retinal venous diameter and contribute to pressure-initiated vascular responses.
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Affiliation(s)
- Hui Li
- Department of Ophthalmology, The Tenth People's Hospital, Shanghai, Tongji University School of Medicine, Shanghai, China 2Devers Eye Institute, Legacy Research Institute, Portland, Oregon, USA
| | - Bang V Bui
- Department of Optometry and Vision Sciences, University of Melbourne, Parkville, Victoria, Australia
| | - Grant Cull
- Devers Eye Institute, Legacy Research Institute, Portland, Oregon, USA
| | - Fang Wang
- Department of Ophthalmology, The Tenth People's Hospital, Shanghai, Tongji University School of Medicine, Shanghai, China
| | - Lin Wang
- Department of Ophthalmology, The Tenth People's Hospital, Shanghai, Tongji University School of Medicine, Shanghai, China 2Devers Eye Institute, Legacy Research Institute, Portland, Oregon, USA
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24
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Zhou XY, Luo Y, Zhu YM, Liu ZH, Kent TA, Rong JG, Li W, Qiao SG, Li M, Ni Y, Ishidoh K, Zhang HL. Inhibition of autophagy blocks cathepsins-tBid-mitochondrial apoptotic signaling pathway via stabilization of lysosomal membrane in ischemic astrocytes. Cell Death Dis 2017; 8:e2618. [PMID: 28206988 PMCID: PMC5386481 DOI: 10.1038/cddis.2017.34] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2016] [Revised: 01/14/2017] [Accepted: 01/16/2017] [Indexed: 01/07/2023]
Abstract
Our previous study and others have demonstrated that autophagy is activated in ischemic astrocytes and contributes to astrocytic cell death. However, the mechanisms of ischemia-induced autophagy remain largely unknown. In this study, we established a rat's model of permanent middle cerebral artery occlusion (pMCAO) and an in vitro oxygen and glucose deprivation (OGD) model. Autophagy was inhibited by either pharmacological treatment with 3-methyladenine (3-MA) and wortmannin (Wort) or genetic treatment with knockdown of Atg5 in primary cultured astrocytes and knockout of Atg5 in mouse embryonic fibroblast (MEF) cells, respectively. We found that pharmacological or genetic inhibition of autophagy reversed pMCAO or OGD-induced increase in LC3-II, active cathepsin B and L, tBid, active caspase-3 and cytoplastic cytochrome c (Cyt-c), and suppressed the injury-induced reduction in mitochondrial Cyt-c in ischemic cortex, in injured astrocytes and MEF cells. Immunofluorescence analysis showed that 3-MA or Wort treatment reversed OGD-induced release of cathepsin B and L from the lysosome to the cytoplasm and activation of caspase-3 in the astrocytes. Furthermore, treatment of 3-MA or Wort decreased OGD-induced increase in lysosomal membrane permeability and enhanced OGD-induced upregulation of lysosomal heat shock protein 70.1B (Hsp70.1B) in astrocytes. Inhibition of autophagy by 3-MA or Wort reduced infarction volume in rats and protected OGD-induced astrocytic cell injury. A non-selective caspase inhibitor z-VAD-fmk or a specific caspase-3 inhibitor Q-DEVD-OPh also rescued OGD-induced astrocytic cell injury. In conclusion, our presenting data suggest that inhibition of autophagy blocks cathepsins–tBid–mitochondrial apoptotic signaling pathway via stabilization of lysosomal membranes, possibly due to upregulation of the lysosomal Hsp70.1B in ischemic astrocytes.
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Affiliation(s)
- Xian-Yong Zhou
- Jiangsu Key Laboratory of Translational Research and Therapy for Neuro-Psycho-Diseases, College of Pharmaceutical Science; Department of Pharmacology and Laboratory of Cerebrovascular Pharmacology; Jiangsu Key Laboratory of Preventive and Translational Medicine for Geriatric Diseases, School of Public Health, Soochow University, Suzhou, China
| | - Yu Luo
- Jiangsu Key Laboratory of Translational Research and Therapy for Neuro-Psycho-Diseases, College of Pharmaceutical Science; Department of Pharmacology and Laboratory of Cerebrovascular Pharmacology; Jiangsu Key Laboratory of Preventive and Translational Medicine for Geriatric Diseases, School of Public Health, Soochow University, Suzhou, China
| | - Yong-Ming Zhu
- Jiangsu Key Laboratory of Translational Research and Therapy for Neuro-Psycho-Diseases, College of Pharmaceutical Science; Department of Pharmacology and Laboratory of Cerebrovascular Pharmacology; Jiangsu Key Laboratory of Preventive and Translational Medicine for Geriatric Diseases, School of Public Health, Soochow University, Suzhou, China
| | - Zhi-He Liu
- Guangzhou Institute of Traumatic Surgery, Guangzhou Red Cross Hospital, Medical College, Jinan University, Guangzhou, China
| | - Thomas A Kent
- Stroke Outcomes Laboratory, Department of Neurology, Baylor College of Medicine, Houston, TX, USA.,Center for Translational Research on Inflammatory Diseases, Michael E DeBakey Veterans Affairs Medical Center, Houston, TX, USA
| | - Jia-Guo Rong
- Jiangsu Key Laboratory of Translational Research and Therapy for Neuro-Psycho-Diseases, College of Pharmaceutical Science; Department of Pharmacology and Laboratory of Cerebrovascular Pharmacology; Jiangsu Key Laboratory of Preventive and Translational Medicine for Geriatric Diseases, School of Public Health, Soochow University, Suzhou, China
| | - Wei Li
- Jiangsu Key Laboratory of Translational Research and Therapy for Neuro-Psycho-Diseases, College of Pharmaceutical Science; Department of Pharmacology and Laboratory of Cerebrovascular Pharmacology; Jiangsu Key Laboratory of Preventive and Translational Medicine for Geriatric Diseases, School of Public Health, Soochow University, Suzhou, China
| | - Shi-Gang Qiao
- Jiangsu Key Laboratory of Translational Research and Therapy for Neuro-Psycho-Diseases, College of Pharmaceutical Science; Department of Pharmacology and Laboratory of Cerebrovascular Pharmacology; Jiangsu Key Laboratory of Preventive and Translational Medicine for Geriatric Diseases, School of Public Health, Soochow University, Suzhou, China
| | - Min Li
- Jiangsu Key Laboratory of Translational Research and Therapy for Neuro-Psycho-Diseases, College of Pharmaceutical Science; Department of Pharmacology and Laboratory of Cerebrovascular Pharmacology; Jiangsu Key Laboratory of Preventive and Translational Medicine for Geriatric Diseases, School of Public Health, Soochow University, Suzhou, China
| | - Yong Ni
- Jiangsu Key Laboratory of Translational Research and Therapy for Neuro-Psycho-Diseases, College of Pharmaceutical Science; Department of Pharmacology and Laboratory of Cerebrovascular Pharmacology; Jiangsu Key Laboratory of Preventive and Translational Medicine for Geriatric Diseases, School of Public Health, Soochow University, Suzhou, China
| | - Kazumi Ishidoh
- Institute for Health Sciences, Division of Molecular Biology, Tokushima Bumi University, Yamashiro-cho, Tokushima City, Tokushima, Japan
| | - Hui-Ling Zhang
- Jiangsu Key Laboratory of Translational Research and Therapy for Neuro-Psycho-Diseases, College of Pharmaceutical Science; Department of Pharmacology and Laboratory of Cerebrovascular Pharmacology; Jiangsu Key Laboratory of Preventive and Translational Medicine for Geriatric Diseases, School of Public Health, Soochow University, Suzhou, China
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Effects of astrocytic dynamics on spatiotemporal hemodynamics: Modeling and enhanced data analysis. Neuroimage 2017; 147:994-1005. [DOI: 10.1016/j.neuroimage.2016.10.023] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2016] [Revised: 10/12/2016] [Accepted: 10/13/2016] [Indexed: 12/11/2022] Open
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Barzilai A, Schumacher B, Shiloh Y. Genome instability: Linking ageing and brain degeneration. Mech Ageing Dev 2017; 161:4-18. [DOI: 10.1016/j.mad.2016.03.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Revised: 03/23/2016] [Accepted: 03/26/2016] [Indexed: 02/06/2023]
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Pappas AC, Koide M, Wellman GC. Purinergic signaling triggers endfoot high-amplitude Ca2+ signals and causes inversion of neurovascular coupling after subarachnoid hemorrhage. J Cereb Blood Flow Metab 2016; 36:1901-1912. [PMID: 27207166 PMCID: PMC5094310 DOI: 10.1177/0271678x16650911] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Accepted: 04/25/2016] [Indexed: 01/09/2023]
Abstract
Neurovascular coupling supports brain metabolism by matching focal increases in neuronal activity with local arteriolar dilation. Previously, we demonstrated that an emergence of spontaneous endfoot high-amplitude Ca2+ signals (eHACSs) caused a pathologic shift in neurovascular coupling from vasodilation to vasoconstriction in brain slices obtained from subarachnoid hemorrhage model animals. Extracellular purine nucleotides (e.g., ATP) can trigger astrocyte Ca2+ oscillations and may be elevated following subarachnoid hemorrhage. Here, the role of purinergic signaling in subarachnoid hemorrhage-induced eHACSs and inversion of neurovascular coupling was examined by imaging parenchymal arteriolar diameter and astrocyte Ca2+ signals in rat brain slices using two-photon fluorescent and infrared-differential interference contrast microscopy. We report that broad-spectrum inhibition of purinergic (P2) receptors using suramin blocked eHACSs and restored vasodilatory neurovascular coupling after subarachnoid hemorrhage. Importantly, eHACSs were also abolished using a cocktail of inhibitors targeting Gq-coupled P2Y receptors. Further, activation of P2Y receptors in brain slices from un-operated animals triggered high-amplitude Ca2+ events resembling eHACSs and disrupted neurovascular coupling. Neither tetrodotoxin nor bafilomycin A1 affected eHACSs suggesting that purine nucleotides are not released by ongoing neurotransmission and/or vesicular release after subarachnoid hemorrhage. These results indicate that purinergic signaling via P2Y receptors contributes to subarachnoid hemorrhage-induced eHACSs and inversion of neurovascular coupling.
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Affiliation(s)
- Anthony C Pappas
- Department of Pharmacology, University of Vermont, Burlington, VT, USA
| | - Masayo Koide
- Department of Pharmacology, University of Vermont, Burlington, VT, USA
| | - George C Wellman
- Department of Pharmacology, University of Vermont, Burlington, VT, USA .,Department of Surgery, Division of Neurosurgery, University of Vermont, Burlington, VT, USA
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Zandt BJ, ten Haken B, van Putten MJAM, Dahlem MA. How does spreading depression spread? Physiology and modeling. Rev Neurosci 2016; 26:183-98. [PMID: 25719306 DOI: 10.1515/revneuro-2014-0069] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2014] [Accepted: 10/31/2014] [Indexed: 11/15/2022]
Abstract
Spreading depression (SD) is a wave phenomenon in gray matter tissue. Locally, it is characterized by massive redistribution of ions across cell membranes. As a consequence, there is sustained membrane depolarization and tissue polarization that depress any normal electrical activity. Despite these dramatic events, SD remains difficult to observe in humans noninvasively, which, for long, has slowed advances in this field. The growing appreciation of its clinical importance in migraine and stroke is therefore consistent with an increasing need for computational methods that tackle the complexity of the problem at multiple levels. In this review, we focus on mathematical tools to investigate the question of spread and its two complementary aspects: What are the physiological mechanisms and what is the spatial extent of SD in the cortex? This review discusses two types of models used to study these two questions, namely, Hodgkin-Huxley type and generic activator-inhibitor models, and the recent advances in techniques to link them.
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Astrocyte Aquaporin Dynamics in Health and Disease. Int J Mol Sci 2016; 17:ijms17071121. [PMID: 27420057 PMCID: PMC4964496 DOI: 10.3390/ijms17071121] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2016] [Revised: 07/07/2016] [Accepted: 07/07/2016] [Indexed: 02/01/2023] Open
Abstract
The family of aquaporins (AQPs), membrane water channels, consists of diverse types of proteins that are mainly permeable to water; some are also permeable to small solutes, such as glycerol and urea. They have been identified in a wide range of organisms, from microbes to vertebrates and plants, and are expressed in various tissues. Here, we focus on AQP types and their isoforms in astrocytes, a major glial cell type in the central nervous system (CNS). Astrocytes have anatomical contact with the microvasculature, pia, and neurons. Of the many roles that astrocytes have in the CNS, they are key in maintaining water homeostasis. The processes involved in this regulation have been investigated intensively, in particular regulation of the permeability and expression patterns of different AQP types in astrocytes. Three aquaporin types have been described in astrocytes: aquaporins AQP1 and AQP4 and aquaglyceroporin AQP9. The aim here is to review their isoforms, subcellular localization, permeability regulation, and expression patterns in the CNS. In the human CNS, AQP4 is expressed in normal physiological and pathological conditions, but astrocytic expression of AQP1 and AQP9 is mainly associated with a pathological state.
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Kaminsky N, Bihari O, Kanner S, Barzilai A. Connecting Malfunctioning Glial Cells and Brain Degenerative Disorders. GENOMICS, PROTEOMICS & BIOINFORMATICS 2016; 14:155-165. [PMID: 27245308 PMCID: PMC4936608 DOI: 10.1016/j.gpb.2016.04.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Revised: 04/21/2016] [Accepted: 04/22/2016] [Indexed: 12/19/2022]
Abstract
The DNA damage response (DDR) is a complex biological system activated by different types of DNA damage. Mutations in certain components of the DDR machinery can lead to genomic instability disorders that culminate in tissue degeneration, premature aging, and various types of cancers. Intriguingly, malfunctioning DDR plays a role in the etiology of late onset brain degenerative disorders such as Parkinson's, Alzheimer's, and Huntington's diseases. For many years, brain degenerative disorders were thought to result from aberrant neural death. Here we discuss the evidence that supports our novel hypothesis that brain degenerative diseases involve dysfunction of glial cells (astrocytes, microglia, and oligodendrocytes). Impairment in the functionality of glial cells results in pathological neuro-glial interactions that, in turn, generate a "hostile" environment that impairs the functionality of neuronal cells. These events can lead to systematic neural demise on a scale that appears to be proportional to the severity of the neurological deficit.
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Affiliation(s)
- Natalie Kaminsky
- Department of Neurobiology, George S. Wise, Faculty of Life Sciences, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Ofer Bihari
- Department of Neurobiology, George S. Wise, Faculty of Life Sciences, Tel Aviv University, Tel Aviv 6997801, Israel; Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Sivan Kanner
- Department of Neurobiology, George S. Wise, Faculty of Life Sciences, Tel Aviv University, Tel Aviv 6997801, Israel.
| | - Ari Barzilai
- Department of Neurobiology, George S. Wise, Faculty of Life Sciences, Tel Aviv University, Tel Aviv 6997801, Israel; Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 6997801, Israel.
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Wang F, Li M, Li X, Kinden R, Zhou H, Guo F, Wang Q, Xiong L. 2-Arachidonylglycerol Protects Primary Astrocytes Exposed to Oxygen-Glucose Deprivation Through a Blockade of NDRG2 Signaling and STAT3 Phosphorylation. Rejuvenation Res 2016; 19:215-22. [PMID: 26414218 DOI: 10.1089/rej.2015.1703] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
The human N-Myc downstream-regulated gene 2 (NDRG2) is expressed in astrocytes, and may be involved in the modulation of gliacyte function in the central nervous system. Our previous study found suppression of NDRG2 up-regulation in reactive astrocytes in cerebral ischemic tolerance. 2-Arachidonylglycerol (2-AG) can induce cerebral ischemic tolerance. However, the underlying mechanism of NDRG2 in cytoprotection induced by 2-AG in primary astrocytesis still unknown. In this study, we investigated the role of NDRG2 in cerebral ischemic tolerance induced by 2-AG after oxygen-glucose deprivation (OGD) in primary astrocytes. The results showed that primary astrocytes exposed to OGD resulted in marked increase of lactate dehydrogenase (LDH) release and decrease of methyl thiazolyl tetrazolium (MTT) reduction activity in comparison to control cultures. The levels of NDRG2 and phospho-signal transducer and activator of transcription 3 (pSTAT3) in the OGD group were comparably higher than those in the control group, and the up-regulation of NDRG2 and pSTAT3 was suppressed in NDRG2 siRNA group. The cell viability in the 2-AG group was higher than that in the OGD group, and transfecting the NDRG2 pSRL-CDH1-GFP vector reversed the protective effects of 2-AG. The levels of NDRG2 and pSTAT3 in the 2-AG group were lower than those in the OGD group. 2-AG suppressed STAT3 phosphorylation by decreased expression of NDRG2. In conclusion, 2-AG protects primary astrocytes exposed to oxygen-glucose deprivation through a blockade of NDRG2 signaling and STAT3 phosphorylation. These findings bring insight to the roles of NDRG2 in ischemic-hypoxic injury and provide novel potential targets for future potent clinical therapies on cerebral ischemia injury.
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Affiliation(s)
- Feng Wang
- 1 Department of Anesthesiology, Xijing Hospital, The Fourth Military Medical University , Xi'an, Shaanxi Province, China
| | - Mo Li
- 2 Department of Orthopaedics, Xijing Hospital, The Fourth Military Medical University , Xi'an, Shaanxi Province, China
| | - Xin Li
- 1 Department of Anesthesiology, Xijing Hospital, The Fourth Military Medical University , Xi'an, Shaanxi Province, China
| | - Renee Kinden
- 3 Department of Psychiatry, University of Ottawa Institute of Mental Health Research at the Royal , Ottawa, Canada
| | - Heng Zhou
- 1 Department of Anesthesiology, Xijing Hospital, The Fourth Military Medical University , Xi'an, Shaanxi Province, China
| | - Fan Guo
- 1 Department of Anesthesiology, Xijing Hospital, The Fourth Military Medical University , Xi'an, Shaanxi Province, China
| | - Qiang Wang
- 1 Department of Anesthesiology, Xijing Hospital, The Fourth Military Medical University , Xi'an, Shaanxi Province, China
| | - Lize Xiong
- 1 Department of Anesthesiology, Xijing Hospital, The Fourth Military Medical University , Xi'an, Shaanxi Province, China
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Astrocyte Ca2+ Signaling Drives Inversion of Neurovascular Coupling after Subarachnoid Hemorrhage. J Neurosci 2015; 35:13375-84. [PMID: 26424885 DOI: 10.1523/jneurosci.1551-15.2015] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Physiologically, neurovascular coupling (NVC) matches focal increases in neuronal activity with local arteriolar dilation. Astrocytes participate in NVC by sensing increased neurotransmission and releasing vasoactive agents (e.g., K(+)) from perivascular endfeet surrounding parenchymal arterioles. Previously, we demonstrated an increase in the amplitude of spontaneous Ca(2+) events in astrocyte endfeet and inversion of NVC from vasodilation to vasoconstriction in brain slices obtained from subarachnoid hemorrhage (SAH) model rats. However, the role of spontaneous astrocyte Ca(2+) signaling in determining the polarity of the NVC response remains unclear. Here, we used two-photon imaging of Fluo-4-loaded rat brain slices to determine whether altered endfoot Ca(2+) signaling underlies SAH-induced inversion of NVC. We report a time-dependent emergence of endfoot high-amplitude Ca(2+) signals (eHACSs) after SAH that were not observed in endfeet from unoperated animals. Furthermore, the percentage of endfeet with eHACSs varied with time and paralleled the development of inversion of NVC. Endfeet with eHACSs were present only around arterioles exhibiting inversion of NVC. Importantly, depletion of intracellular Ca(2+) stores using cyclopiazonic acid abolished SAH-induced eHACSs and restored arteriolar dilation in SAH brain slices to two mediators of NVC (a rise in endfoot Ca(2+) and elevation of extracellular K(+)). These data indicate a causal link between SAH-induced eHACSs and inversion of NVC. Ultrastructural examination using transmission electron microscopy indicated that a similar proportion of endfeet exhibiting eHACSs also exhibited asymmetrical enlargement. Our results demonstrate that subarachnoid blood causes a delayed increase in the amplitude of spontaneous intracellular Ca(2+) release events leading to inversion of NVC. Significance statement: Aneurysmal subarachnoid hemorrhage (SAH)--strokes involving cerebral aneurysm rupture and release of blood onto the brain surface--are associated with high rates of morbidity and mortality. A common complication observed after SAH is the development of delayed cerebral ischemia at sites often remote from the site of rupture. Here, we provide evidence that SAH-induced changes in astrocyte Ca(2+) signaling lead to a switch in the polarity of the neurovascular coupling response from vasodilation to vasoconstriction. Thus, after SAH, signaling events that normally lead to vasodilation and enhanced delivery of blood to active brain regions cause vasoconstriction that would limit cerebral blood flow. These findings identify astrocytes as a key player in SAH-induced decreased cortical blood flow.
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Mohn TC, Koob AO. Adult Astrogenesis and the Etiology of Cortical Neurodegeneration. J Exp Neurosci 2015; 9:25-34. [PMID: 26568684 PMCID: PMC4634839 DOI: 10.4137/jen.s25520] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Revised: 10/06/2015] [Accepted: 10/08/2015] [Indexed: 01/09/2023] Open
Abstract
As more evidence points to a clear role for astrocytes in synaptic processing, synaptogenesis and cognition, continuing research on astrocytic function could lead to strategies for neurodegenerative disease prevention. Reactive astrogliosis results in astrocyte proliferation early in injury and disease states and is considered neuroprotective, indicating a role for astrocytes in disease etiology. This review describes the different types of human cortical astrocytes and the current evidence regarding adult cortical astrogenesis in injury and degenerative disease. A role for disrupted astrogenesis as a cause of cortical degeneration, with a focus on the tauopathies and synucleinopathies, will also be considered.
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Affiliation(s)
- Tal C. Mohn
- Biology Department, University of Wisconsin—River Falls, River Falls, Wisconsin, USA
| | - Andrew O. Koob
- Biology Department, University of Wisconsin—River Falls, River Falls, Wisconsin, USA
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Vardjan N, Verkhratsky A, Zorec R. Pathologic Potential of Astrocytic Vesicle Traffic: New Targets to Treat Neurologic Diseases? Cell Transplant 2015; 24:599-612. [DOI: 10.3727/096368915x687750] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Vesicles are small intracellular organelles that are fundamental for constitutive housekeeping of the plasmalemma, intercellular transport, and cell-to-cell communications. In astroglial cells, traffic of vesicles is associated with cell morphology, which determines the signaling potential and metabolic support for neighboring cells, including when these cells are considered to be used for cell transplantations or for regulating neurogenesis. Moreover, vesicles are used in astrocytes for the release of vesicle-laden chemical messengers. Here we review the properties of membrane-bound vesicles that store gliotransmitters, endolysosomes that are involved in the traffic of plasma membrane receptors, and membrane transporters. These vesicles are all linked to pathological states, including amyotrophic lateral sclerosis, multiple sclerosis, neuroinflammation, trauma, edema, and states in which astrocytes contribute to developmental disorders. In multiple sclerosis, for example, fingolimod, a recently introduced drug, apparently affects vesicle traffic and gliotransmitter release from astrocytes, indicating that this process may well be used as a new pathophysiologic target for the development of new therapies.
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Affiliation(s)
- Nina Vardjan
- Celica Biomedical, Ljubljana, Slovenia
- Laboratory of Neuroendocrinology-Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Alexei Verkhratsky
- Celica Biomedical, Ljubljana, Slovenia
- Laboratory of Neuroendocrinology-Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
- Achucarro Center for Neuroscience, Ikerbasque, Basque Foundation for Science, Bilbao, Spain
- Faculty of Life Sciences, The University of Manchester, Manchester, UK
| | - Robert Zorec
- Celica Biomedical, Ljubljana, Slovenia
- Laboratory of Neuroendocrinology-Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
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Nicaise C, Mitrecic D, Falnikar A, Lepore AC. Transplantation of stem cell-derived astrocytes for the treatment of amyotrophic lateral sclerosis and spinal cord injury. World J Stem Cells 2015; 7:380-398. [PMID: 25815122 PMCID: PMC4369494 DOI: 10.4252/wjsc.v7.i2.380] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/29/2014] [Revised: 10/07/2014] [Accepted: 11/19/2014] [Indexed: 02/06/2023] Open
Abstract
Neglected for years, astrocytes are now recognized to fulfill and support many, if not all, homeostatic functions of the healthy central nervous system (CNS). During neurodegenerative diseases such as amyotrophic lateral sclerosis (ALS) and spinal cord injury (SCI), astrocytes in the vicinity of degenerating areas undergo both morphological and functional changes that might compromise their intrinsic properties. Evidence from human and animal studies show that deficient astrocyte functions or loss-of-astrocytes largely contribute to increased susceptibility to cell death for neurons, oligodendrocytes and axons during ALS and SCI disease progression. Despite exciting advances in experimental CNS repair, most of current approaches that are translated into clinical trials focus on the replacement or support of spinal neurons through stem cell transplantation, while none focus on the specific replacement of astroglial populations. Knowing the important functions carried out by astrocytes in the CNS, astrocyte replacement-based therapies might be a promising approach to alleviate overall astrocyte dysfunction, deliver neurotrophic support to degenerating spinal tissue and stimulate endogenous CNS repair abilities. Enclosed in this review, we gathered experimental evidence that argue in favor of astrocyte transplantation during ALS and SCI. Based on their intrinsic properties and according to the cell type transplanted, astrocyte precursors or stem cell-derived astrocytes promote axonal growth, support mechanisms and cells involved in myelination, are able to modulate the host immune response, deliver neurotrophic factors and provide protective molecules against oxidative or excitotoxic insults, amongst many possible benefits. Embryonic or adult stem cells can even be genetically engineered in order to deliver missing gene products and therefore maximize the chance of neuroprotection and functional recovery. However, before broad clinical translation, further preclinical data on safety, reliability and therapeutic efficiency should be collected. Although several technical challenges need to be overcome, we discuss the major hurdles that have already been met or solved by targeting the astrocyte population in experimental ALS and SCI models and we discuss avenues for future directions based on latest molecular findings regarding astrocyte biology.
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Muñoz MF, Puebla M, Figueroa XF. Control of the neurovascular coupling by nitric oxide-dependent regulation of astrocytic Ca(2+) signaling. Front Cell Neurosci 2015; 9:59. [PMID: 25805969 PMCID: PMC4354411 DOI: 10.3389/fncel.2015.00059] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Accepted: 02/07/2015] [Indexed: 12/28/2022] Open
Abstract
Neuronal activity must be tightly coordinated with blood flow to keep proper brain function, which is achieved by a mechanism known as neurovascular coupling. Then, an increase in synaptic activity leads to a dilation of local parenchymal arterioles that matches the enhanced metabolic demand. Neurovascular coupling is orchestrated by astrocytes. These glial cells are located between neurons and the microvasculature, with the astrocytic endfeet ensheathing the vessels, which allows fine intercellular communication. The neurotransmitters released during neuronal activity reach astrocytic receptors and trigger a Ca2+ signaling that propagates to the endfeet, activating the release of vasoactive factors and arteriolar dilation. The astrocyte Ca2+ signaling is coordinated by gap junction channels and hemichannels formed by connexins (Cx43 and Cx30) and channels formed by pannexins (Panx-1). The neuronal activity-initiated Ca2+ waves are propagated among neighboring astrocytes directly via gap junctions or through ATP release via connexin hemichannels or pannexin channels. In addition, Ca2+ entry via connexin hemichannels or pannexin channels may participate in the regulation of the astrocyte signaling-mediated neurovascular coupling. Interestingly, nitric oxide (NO) can activate connexin hemichannel by S-nitrosylation and the Ca2+-dependent NO-synthesizing enzymes endothelial NO synthase (eNOS) and neuronal NOS (nNOS) are expressed in astrocytes. Therefore, the astrocytic Ca2+ signaling triggered in neurovascular coupling may activate NO production, which, in turn, may lead to Ca2+ influx through hemichannel activation. Furthermore, NO release from the hemichannels located at astrocytic endfeet may contribute to the vasodilation of parenchymal arterioles. In this review, we discuss the mechanisms involved in the regulation of the astrocytic Ca2+ signaling that mediates neurovascular coupling, with a special emphasis in the possible participation of NO in this process.
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Affiliation(s)
- Manuel F Muñoz
- Facultad de Ciencias Biológicas, Departamento de Fisiología, Pontificia Universidad Católica de Chile Santiago, Chile
| | - Mariela Puebla
- Facultad de Ciencias Biológicas, Departamento de Fisiología, Pontificia Universidad Católica de Chile Santiago, Chile
| | - Xavier F Figueroa
- Facultad de Ciencias Biológicas, Departamento de Fisiología, Pontificia Universidad Católica de Chile Santiago, Chile
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Peixoto CA, Nunes AKS, Garcia-Osta A. Phosphodiesterase-5 Inhibitors: Action on the Signaling Pathways of Neuroinflammation, Neurodegeneration, and Cognition. Mediators Inflamm 2015; 2015:940207. [PMID: 26770022 PMCID: PMC4681825 DOI: 10.1155/2015/940207] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2015] [Accepted: 11/08/2015] [Indexed: 12/16/2022] Open
Abstract
Phosphodiesterase type 5 inhibitors (PDE5-Is) have recently emerged as a potential therapeutic strategy for neuroinflammatory, neurodegenerative, and memory loss diseases. Mechanistically, PDE5-Is produce an anti-inflammatory and neuroprotection effect by increasing expression of nitric oxide synthases and accumulation of cGMP and activating protein kinase G (PKG), the signaling pathway of which is thought to play an important role in the development of several neurodiseases, such as Alzheimer's disease (AD), Parkinson's disease (PD), and multiple sclerosis (MS). The aim of this paper was to review present knowledge of the signaling pathways that underlie the use of PDE5-Is in neuroinflammation, neurogenesis, learning, and memory.
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Affiliation(s)
- Christina Alves Peixoto
- 1Laboratório de Ultraestrutura, Centro de Pesquisa Aggeu Magalhães (FIOCRUZ), 50.740-465 Recife, PE, Brazil
- *Christina Alves Peixoto:
| | - Ana Karolina Santana Nunes
- 1Laboratório de Ultraestrutura, Centro de Pesquisa Aggeu Magalhães (FIOCRUZ), 50.740-465 Recife, PE, Brazil
- 2Universidade Federal de Pernambuco, 50.670-901 Recife, PE, Brazil
| | - Ana Garcia-Osta
- 3Neurobiology of Alzheimer's disease, Neurosciences Division, Center for Applied Medical Research (CIMA), University of Navarra, Pamplona, Spain
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p38α (MAPK14) critically regulates the immunological response and the production of specific cytokines and chemokines in astrocytes. Sci Rep 2014; 4:7405. [PMID: 25502009 PMCID: PMC4264013 DOI: 10.1038/srep07405] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2014] [Accepted: 11/19/2014] [Indexed: 02/08/2023] Open
Abstract
In CNS lesions, “reactive astrocytes” form a prominent cellular response. However, the nature of this astrocyte immune activity is not well understood. In order to study astrocytic immune responses to inflammation and injury, we generated mice with conditional deletion of p38α (MAPK14) in GFAP+ astrocytes. We studied the role of p38α signaling in astrocyte immune activation both in vitro and in vivo, and simultaneously examined the effects of astrocyte activation in CNS inflammation. Our results showed that specific subsets of cytokines (TNFα, IL-6) and chemokines (CCL2, CCL4, CXCL1, CXCL2, CXCL10) are critically regulated by p38α signaling in astrocytes. In an in vivo CNS inflammation model of intracerebral injection of LPS, we observed markedly attenuated astrogliosis in conditional GFAPcre p38α−/− mice. However, GFAPcre p38α−/− mice showed marked upregulation of CCL2, CCL3, CCL4, CXCL2, CXCL10, TNFα, and IL-1β compared to p38αfl/fl cohorts, suggesting that in vivo responses to LPS after GFAPcre p38α deletion are complex and involve interactions between multiple cell types. This finding was supported by a prominent increase in macrophage/microglia and neutrophil recruitment in GFAPcre p38α−/− mice compared to p38αfl/fl controls. Together, these studies provide important insights into the critical role of p38α signaling in astrocyte immune activation.
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Dorsal subthalamic nucleus electrical stimulation for drug/treatment-refractory epilepsy may modulate melanocortinergic signaling in astrocytes. Epilepsy Behav 2014; 36:6-8. [PMID: 24835897 DOI: 10.1016/j.yebeh.2014.04.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/05/2014] [Accepted: 04/17/2014] [Indexed: 12/17/2022]
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Orellana JA, Stehberg J. Hemichannels: new roles in astroglial function. Front Physiol 2014; 5:193. [PMID: 24987373 PMCID: PMC4060415 DOI: 10.3389/fphys.2014.00193] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Accepted: 05/07/2014] [Indexed: 01/16/2023] Open
Abstract
The role of astrocytes in brain function has evolved over the last decade, from support cells to active participants in the neuronal synapse through the release of "gliotransmitters."Astrocytes express receptors for most neurotransmitters and respond to them through Ca(2+) intracellular oscillations and propagation of intercellular Ca(2+) waves. While such waves are able to propagate among neighboring astrocytes through gap junctions, thereby activating several astrocytes simultaneously, they can also trigger the release of gliotransmitters, including glutamate, d-serine, glycine, ATP, adenosine, or GABA. There are several mechanisms by which gliotransmitter release occurs, including functional hemichannels. These gliotransmitters can activate neighboring astrocytes and participate in the propagation of intercellular Ca(2+) waves, or activate pre- and post-synaptic receptors, including NMDA, AMPA, and purinergic receptors. In consequence, hemichannels could play a pivotal role in astrocyte-to-astrocyte communication and astrocyte-to-neuron cross-talk. Recent evidence suggests that astroglial hemichannels are involved in higher brain functions including memory and glucose sensing. The present review will focus on the role of hemichannels in astrocyte-to-astrocyte and astrocyte-to neuron communication and in brain physiology.
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Affiliation(s)
- Juan A Orellana
- Departamento de Neurología, Escuela de Medicina, Pontificia Universidad Católica de Chile Santiago, Chile
| | - Jimmy Stehberg
- Laboratorio de Neurobiología, Centro de Investigaciones Médicas, Facultad de Ciencias Biológicas and Facultad de Medicina, Universidad Andrés Bello Santiago, Chile
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Chen S, Feng H, Sherchan P, Klebe D, Zhao G, Sun X, Zhang J, Tang J, Zhang JH. Controversies and evolving new mechanisms in subarachnoid hemorrhage. Prog Neurobiol 2014; 115:64-91. [PMID: 24076160 PMCID: PMC3961493 DOI: 10.1016/j.pneurobio.2013.09.002] [Citation(s) in RCA: 270] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2013] [Revised: 09/07/2013] [Accepted: 09/12/2013] [Indexed: 12/13/2022]
Abstract
Despite decades of study, subarachnoid hemorrhage (SAH) continues to be a serious and significant health problem in the United States and worldwide. The mechanisms contributing to brain injury after SAH remain unclear. Traditionally, most in vivo research has heavily emphasized the basic mechanisms of SAH over the pathophysiological or morphological changes of delayed cerebral vasospasm after SAH. Unfortunately, the results of clinical trials based on this premise have mostly been disappointing, implicating some other pathophysiological factors, independent of vasospasm, as contributors to poor clinical outcomes. Delayed cerebral vasospasm is no longer the only culprit. In this review, we summarize recent data from both experimental and clinical studies of SAH and discuss the vast array of physiological dysfunctions following SAH that ultimately lead to cell death. Based on the progress in neurobiological understanding of SAH, the terms "early brain injury" and "delayed brain injury" are used according to the temporal progression of SAH-induced brain injury. Additionally, a new concept of the vasculo-neuronal-glia triad model for SAH study is highlighted and presents the challenges and opportunities of this model for future SAH applications.
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Affiliation(s)
- Sheng Chen
- Department of Neurosurgery, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China; Department of Physiology & Pharmacology, Loma Linda University, Loma Linda, CA, USA
| | - Hua Feng
- Department of Neurosurgery, Southwest Hospital, Third Military Medical University, Chongqing, China
| | - Prativa Sherchan
- Department of Physiology & Pharmacology, Loma Linda University, Loma Linda, CA, USA
| | - Damon Klebe
- Department of Physiology & Pharmacology, Loma Linda University, Loma Linda, CA, USA
| | - Gang Zhao
- Department of Neurology, Xijing Hospital, Fourth Military Medical University, Xi'an, Shanxi, China
| | - Xiaochuan Sun
- Department of Neurosurgery, First Affiliated Hospital, Chongqing Medical University, Chongqing, China
| | - Jianmin Zhang
- Department of Neurosurgery, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Jiping Tang
- Department of Physiology & Pharmacology, Loma Linda University, Loma Linda, CA, USA
| | - John H Zhang
- Department of Physiology & Pharmacology, Loma Linda University, Loma Linda, CA, USA; Department of Neurosurgery, Loma Linda University, Loma Linda, CA, USA.
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Klohs J, Rudin M, Shimshek DR, Beckmann N. Imaging of cerebrovascular pathology in animal models of Alzheimer's disease. Front Aging Neurosci 2014; 6:32. [PMID: 24659966 PMCID: PMC3952109 DOI: 10.3389/fnagi.2014.00032] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2013] [Accepted: 02/19/2014] [Indexed: 01/04/2023] Open
Abstract
In Alzheimer's disease (AD), vascular pathology may interact with neurodegeneration and thus aggravate cognitive decline. As the relationship between these two processes is poorly understood, research has been increasingly focused on understanding the link between cerebrovascular alterations and AD. This has at last been spurred by the engineering of transgenic animals, which display pathological features of AD and develop cerebral amyloid angiopathy to various degrees. Transgenic models are versatile for investigating the role of amyloid deposition and vascular dysfunction, and for evaluating novel therapeutic concepts. In addition, research has benefited from the development of novel imaging techniques, which are capable of characterizing vascular pathology in vivo. They provide vascular structural read-outs and have the ability to assess the functional consequences of vascular dysfunction as well as to visualize and monitor the molecular processes underlying these pathological alterations. This article focusses on recent in vivo small animal imaging studies addressing vascular aspects related to AD. With the technical advances of imaging modalities such as magnetic resonance, nuclear and microscopic imaging, molecular, functional and structural information related to vascular pathology can now be visualized in vivo in small rodents. Imaging vascular and parenchymal amyloid-β (Aβ) deposition as well as Aβ transport pathways have been shown to be useful to characterize their dynamics and to elucidate their role in the development of cerebral amyloid angiopathy and AD. Structural and functional imaging read-outs have been employed to describe the deleterious affects of Aβ on vessel morphology, hemodynamics and vascular integrity. More recent imaging studies have also addressed how inflammatory processes partake in the pathogenesis of the disease. Moreover, imaging can be pivotal in the search for novel therapies targeting the vasculature.
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Affiliation(s)
- Jan Klohs
- Institute for Biomedical Engineering, University of Zurich and ETH Zurich Zurich, Switzerland ; Neuroscience Center Zurich, University of Zurich and ETH Zurich Zurich, Switzerland
| | - Markus Rudin
- Institute for Biomedical Engineering, University of Zurich and ETH Zurich Zurich, Switzerland ; Neuroscience Center Zurich, University of Zurich and ETH Zurich Zurich, Switzerland ; Institute of Pharmacology and Toxicology, University of Zurich Zurich, Switzerland
| | - Derya R Shimshek
- Autoimmunity, Transplantation and Inflammation/Neuroinflammation Department, Novartis Institutes for BioMedical Research Basel, Switzerland
| | - Nicolau Beckmann
- Analytical Sciences and Imaging, Novartis Institutes for BioMedical Research Basel, Switzerland
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G-protein coupled receptor-evoked glutamate exocytosis from astrocytes: role of prostaglandins. Neural Plast 2014; 2014:254574. [PMID: 24551459 PMCID: PMC3914554 DOI: 10.1155/2014/254574] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2013] [Accepted: 12/16/2013] [Indexed: 11/17/2022] Open
Abstract
Astrocytes are highly secretory cells, participating in rapid brain communication by releasing glutamate. Recent evidences have suggested that this process is largely mediated by Ca(2+)-dependent regulated exocytosis of VGLUT-positive vesicles. Here by taking advantage of VGLUT1-pHluorin and TIRF illumination, we characterized mechanisms of glutamate exocytosis evoked by endogenous transmitters (glutamate and ATP), which are known to stimulate Ca(2+) elevations in astrocytes. At first we characterized the VGLUT1-pHluorin expressing vesicles and found that VGLUT1-positive vesicles were a specific population of small synaptic-like microvesicles containing glutamate but which do not express VGLUT2. Endogenous mediators evoked a burst of exocytosis through activation of G-protein coupled receptors. Subsequent glutamate exocytosis was reduced by about 80% upon pharmacological blockade of the prostaglandin-forming enzyme, cyclooxygenase. On the other hand, receptor stimulation was accompanied by extracellular release of prostaglandin E2 (PGE2). Interestingly, administration of exogenous PGE2 produced per se rapid, store-dependent burst exocytosis of glutamatergic vesicles in astrocytes. Finally, when PGE2-neutralizing antibody was added to cell medium, transmitter-evoked exocytosis was again significantly reduced (by about 50%). Overall these data indicate that cyclooxygenase products are responsible for a major component of glutamate exocytosis in astrocytes and that large part of such component is sustained by autocrine/paracrine action of PGE2.
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Vardjan N, Kreft M, Zorec R. Regulated Exocytosis in Astrocytes is as Slow as the Metabolic Availability of Gliotransmitters: Focus on Glutamate and ATP. GLUTAMATE AND ATP AT THE INTERFACE OF METABOLISM AND SIGNALING IN THE BRAIN 2014; 11:81-101. [DOI: 10.1007/978-3-319-08894-5_5] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Wong DPK, Chu JMT, Hung VKL, Lee DKM, Cheng CHK, Yung KKL, Yue KKM. Modulation of endoplasmic reticulum chaperone GRP78 by high glucose in hippocampus of streptozotocin-induced diabetic mice and C6 astrocytic cells. Neurochem Int 2013; 63:551-60. [PMID: 24056253 DOI: 10.1016/j.neuint.2013.09.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2013] [Revised: 09/09/2013] [Accepted: 09/12/2013] [Indexed: 12/15/2022]
Abstract
Diabetes mellitus is known to increase the risk of neurodegeneration, and both diseases are reported to be linked to dysfunction of endoplasmic reticulum (ER). Astrocytes are important in the defense mechanism of central nervous system (CNS), with great ability of tolerating accumulation of toxic substances and sensitivity in Ca(2+) homeostasis which are two key functions of ER. Here, we investigated the modulation of the glucose-regulated protein 78 (GRP78) in streptozotocin (STZ)-induced diabetic mice and C6 cells cultured in high glucose condition. Our results showed that more reactive astrocytes were presented in the hippocampus of STZ-induced diabetic mice. Simultaneously, decrease of GRP78 expression was found in the astrocytes of diabetic mice hippocampus. In in vitro study, C6 cells were treated with high glucose to investigate the role of high glucose in GRP78 modulation in astrocytic cells. GRP78 as well as other chaperones like GRP94, calreticulin and calnexin, transcription levels were down-regulated after high glucose treatment. Also C6 cells challenged with 48h high glucose were activated, as indicated by increased level of glial fibrillary acidic protein (GFAP). Activated C6 cells simultaneously exhibited significant decrease of GRP78 level and was followed by reduced phosphorylation of Akt. Moreover, unfolded protein response was induced as an early event, which was marked by the induction of CHOP with high glucose treatment, followed by the reduction of GRP78 after 48h. Finally, the upsurge of ROS production was found in high glucose treated C6 cells and chelation of ROS could partially restore the GRP78 expression. Taken together, these data provide evidences that high glucose induced astrocytic activation in both in vivo and in vitro diabetic models, in which modulation of GRP78 would be an important event in this activation.
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Affiliation(s)
| | - John M T Chu
- School of Chinese Medicine, Hong Kong Baptist University, Hong Kong; Department of Biology, Hong Kong Baptist University, Hong Kong
| | - Victor K L Hung
- Department of Anaestheiology, The University of Hong Kong, Hong Kong
| | - Dicky K M Lee
- School of Chinese Medicine, Hong Kong Baptist University, Hong Kong
| | | | - Ken K L Yung
- Department of Biology, Hong Kong Baptist University, Hong Kong
| | - Kevin K M Yue
- School of Chinese Medicine, Hong Kong Baptist University, Hong Kong.
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Miguel-Hidalgo JJ, Jiang W, Konick L, Overholser JC, Jurjus GJ, Stockmeier CA, Steffens D, Krishnan KRR, Rajkowska G. Morphometric analysis of vascular pathology in the orbitofrontal cortex of older subjects with major depression. Int J Geriatr Psychiatry 2013. [PMID: 23208772 PMCID: PMC3679255 DOI: 10.1002/gps.3911] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
OBJECTIVE Late-life depression has been associated with risk for cerebrovascular pathology, as demonstrated in neuroimaging studies of older depressed patients, as well as mood disorder following cerebrovascular accidents. However, more research is needed on neuroanatomical changes in late-life depression, where there has been no clearly documented link to brain injury. Such studies should examine morphological changes in medium and small sized vessels that supply the cortical gray and white matter. METHODS The present study used a non-specific histological Nissl staining and a more vessel-specific immunolabeling with endothelial marker von Willebrand Factor (vWF) to estimate density and size of blood vessel segments in the orbitofrontal cortex of 16 older subjects with major depressive disorder (MDD) and 9 non-psychiatric comparison subjects. RESULTS The density of Nissl-stained vessel segments and of segments with perivascular spaces was higher in subjects with MDD than in comparison subjects in gray (GM) and white matter (WM). In GM, the density of vWF-immunoreactive segments with cross-sectional areas greater than 800 µm2 was higher in MDD. In WM, only the density of vWF-immunoreactive segments with patent perivascular spaces and diameters larger than 60 µm was higher in subjects with MDD. Also in the WM, only subjects with late-onset MDD presented a significantly higher density of vWF-positive segments than comparison subjects. CONCLUSIONS In older subjects with MDD, there appear to be morphological changes that increase visibility of medium-sized vessel segments with some labeling techniques, and this increased visibility may be related to increased patency of perivascular spaces around arterioles.
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Affiliation(s)
| | - Wei Jiang
- Psychiatry and Behavioral Sciences, Duke University Medical Center, Durham, NC
| | - Lisa Konick
- Psychiatry, Case Western Reserve University, Cleveland, OH
| | | | - George J. Jurjus
- Psychiatry, Case Western Reserve University, Cleveland, OH,Department of Psychiatry, Cleveland VA Medical Center, Cleveland, OH
| | - Craig A. Stockmeier
- Psychiatry and Human Behavior, University of Mississippi Medical Center, Jackson, MS,Psychiatry, Case Western Reserve University, Cleveland, OH
| | - David Steffens
- Psychiatry and Behavioral Sciences, Duke University Medical Center, Durham, NC
| | | | - Grazyna Rajkowska
- Psychiatry and Human Behavior, University of Mississippi Medical Center, Jackson, MS
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Jovčevska I, Kočevar N, Komel R. Glioma and glioblastoma - how much do we (not) know? Mol Clin Oncol 2013; 1:935-941. [PMID: 24649273 DOI: 10.3892/mco.2013.172] [Citation(s) in RCA: 121] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2013] [Accepted: 08/02/2013] [Indexed: 12/18/2022] Open
Abstract
Cancer is a heterogeneous disease, which provides a broad field for investigation, while simultaneously reducing the chances for a universal treatment. Malignant gliomas are the most common type of primary brain tumors. The heterogeneity of gliomas regarding clinical presentation, pathology and response to treatment makes this type of tumor a challenging area of research. As the clinical symptoms may be unspecific (e.g., seizures and headaches) it is often difficult to diagnose a patient in the early stages of the disease. Thus far, there are no known genetic patterns of inheritance of this disease. Currently, the treatment of glioblastoma involves surgery, whenever possible, followed by radiation and chemotherapy. Experimental procedures, such as passive and active immunotherapy, use of angiogenesis inhibitors in combination with chemotherapeutics and gene/antibody therapy, are additional treatment options. However, as the brain is difficult to access due to the presence of the blood-brain barrier (BBB), none of the above-mentioned therapies have been successful in curing this disease. The lack of knowledge regarding the mechanisms underlying the development and progression of gliomas further adds to the difficulties. Currently, investigations are focused on the development of novel methods for improving the outcome of this disease. However, despite the extensive investigations, 88% of all glioblastoma multiforme (GBM) patients succumb to the disease within 3 years. GBM remains one of the most challenging malignancies worldwide.
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Affiliation(s)
- Ivana Jovčevska
- Medical Center for Molecular Biology, Institute of Biochemistry, Faculty of Medicine, University of Ljubljana, Ljubljana 1000, Slovenia
| | - Nina Kočevar
- Medical Center for Molecular Biology, Institute of Biochemistry, Faculty of Medicine, University of Ljubljana, Ljubljana 1000, Slovenia
| | - Radovan Komel
- Medical Center for Molecular Biology, Institute of Biochemistry, Faculty of Medicine, University of Ljubljana, Ljubljana 1000, Slovenia
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Yang L, Wang S, Li CS. Effect of continuous compression and 30:2 cardiopulmonary resuscitation on cerebral microcirculation in a porcine model of cardiac arrest. Scand J Trauma Resusc Emerg Med 2013; 21:55. [PMID: 23849600 PMCID: PMC3750813 DOI: 10.1186/1757-7241-21-55] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2012] [Accepted: 07/10/2013] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The effect of rescue breathing on neurologic prognosis after cardiopulmonary resuscitation (CPR) is controversial. Therefore, we investigated the cerebral microcirculatory and oxygen metabolism during continuous compression (CC) and 30:2 CPR (VC) in a porcine model of cardiac arrest to determine which is better for neurologic prognosis after CPR. METHODS After 4 min of ventricular fibrillation, 20 pigs were randomised into two groups (n=10/group) receiving CC-CPR or VC-CPR. Cerebral oxygen metabolism and blood flow were measured continuously using laser Doppler flowmetry. Haemodynamic data were recorded at baseline and 5 min, 30 min, 2 h and 4 h after restoration of spontaneous circulation (ROSC). RESULTS Compared with the VC group, the mean cortical cerebral blood flow was significantly higher at 5 min ROSC in the CC group (P<0.05), but the difference disappeared after that time point. Brain percutaneous oxygen partial pressures were higher, and brain percutaneous carbon dioxide partial pressures were lower, in the VC group from 30 min to 4 h after ROSC; significant differences were found between the two groups (P<0.05). However, no significant difference of the cerebral oxygen extraction fraction existed between the two groups. CONCLUSIONS Inconsistency of systemic circulation and cerebral microcirculation with regard to blood perfusion and oxygen metabolism is common after CPR. No significant differences in cortical blood flow and oxygen metabolism were found between the CC-CPR and VC-CPR groups after ROSC.
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Affiliation(s)
- Lin Yang
- Department of Emergency Medicine, Beijing Chao-Yang Hospital, Affiliated to Capital Medical University, Chaoyang District, Beijing 100020, China
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Sonntag WE, Deak F, Ashpole N, Toth P, Csiszar A, Freeman W, Ungvari Z. Insulin-like growth factor-1 in CNS and cerebrovascular aging. Front Aging Neurosci 2013; 5:27. [PMID: 23847531 PMCID: PMC3698444 DOI: 10.3389/fnagi.2013.00027] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Accepted: 06/14/2013] [Indexed: 12/26/2022] Open
Abstract
Insulin-like growth factor-1 (IGF-1) is an important anabolic hormone that decreases with age. In the past two decades, extensive research has determined that the reduction in IGF-1 is an important component of the age-related decline in cognitive function in multiple species including humans. Deficiency in circulating IGF-1 results in impairment in processing speed and deficiencies in both spatial and working memory. Replacement of IGF-1 or factors that increase IGF-1 to old animals and humans reverses many of these cognitive deficits. Despite the overwhelming evidence for IGF-1 as an important neurotrophic agent, the specific mechanisms through which IGF-1 acts have remained elusive. Recent evidence indicates that IGF-1 is both produced by and has important actions on the cerebrovasculature as well as neurons and glia. Nevertheless, the specific regulation and actions of brain- and vascular-derived IGF-1 is poorly understood. The diverse effects of IGF-1 discovered thus far reveal a complex endocrine and paracrine system essential for integrating many of the functions necessary for brain health. Identification of the mechanisms of IGF-1 actions will undoubtedly provide critical insight into regulation of brain function in general and the causes of cognitive decline with age.
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Affiliation(s)
- William E Sonntag
- Reynolds Oklahoma Center on Aging, Department of Geriatric Medicine, University of Oklahoma Health Sciences Center Oklahoma City, OK, USA
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