101
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Tedoldi A, Argent L, Montgomery JM. The role of the tripartite synapse in the heart: how glial cells may contribute to the physiology and pathophysiology of the intracardiac nervous system. Am J Physiol Cell Physiol 2020; 320:C1-C14. [PMID: 33085497 DOI: 10.1152/ajpcell.00363.2020] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
One of the major roles of the intracardiac nervous system (ICNS) is to act as the final site of signal integration for efferent information destined for the myocardium to enable local control of heart rate and rhythm. Multiple subtypes of neurons exist in the ICNS where they are organized into clusters termed ganglionated plexi (GP). The majority of cells in the ICNS are actually glial cells; however, despite this, ICNS glial cells have received little attention to date. In the central nervous system, where glial cell function has been widely studied, glia are no longer viewed simply as supportive cells but rather have been shown to play an active role in modulating neuronal excitability and synaptic plasticity. Pioneering studies have demonstrated that in addition to glia within the brain stem, glial cells within multiple autonomic ganglia in the peripheral nervous system, including the ICNS, can also act to modulate cardiovascular function. Clinically, patients with atrial fibrillation (AF) undergoing catheter ablation show high plasma levels of S100B, a protein produced by cardiac glial cells, correlated with decreased AF recurrence. Interestingly, S100B also alters GP neuron excitability and neurite outgrowth in the ICNS. These studies highlight the importance of understanding how glial cells can affect the heart by modulating GP neuron activity or synaptic inputs. Here, we review studies investigating glia both in the central and peripheral nervous systems to discuss the potential role of glia in controlling cardiac function in health and disease, paying particular attention to the glial cells of the ICNS.
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Affiliation(s)
- Angelo Tedoldi
- Department of Physiology, University of Auckland, Auckland, New Zealand.,Manaaki Mānawa Centre for Heart Research, University of Auckland, Auckland, New Zealand
| | - Liam Argent
- Department of Physiology, University of Auckland, Auckland, New Zealand.,Manaaki Mānawa Centre for Heart Research, University of Auckland, Auckland, New Zealand
| | - Johanna M Montgomery
- Department of Physiology, University of Auckland, Auckland, New Zealand.,Manaaki Mānawa Centre for Heart Research, University of Auckland, Auckland, New Zealand
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102
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Cheli VT, Correale J, Paez PM, Pasquini JM. Iron Metabolism in Oligodendrocytes and Astrocytes, Implications for Myelination and Remyelination. ASN Neuro 2020; 12:1759091420962681. [PMID: 32993319 PMCID: PMC7545512 DOI: 10.1177/1759091420962681] [Citation(s) in RCA: 67] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Iron is a key nutrient for normal central nervous system (CNS) development and function; thus, iron deficiency as well as iron excess may result in harmful effects in the CNS. Oligodendrocytes and astrocytes are crucial players in brain iron equilibrium. However, the mechanisms of iron uptake, storage, and efflux in oligodendrocytes and astrocytes during CNS development or under pathological situations such as demyelination are not completely understood. In the CNS, iron is directly required for myelin production as a cofactor for enzymes involved in ATP, cholesterol and lipid synthesis, and oligodendrocytes are the cells with the highest iron levels in the brain which is linked to their elevated metabolic needs associated with the process of myelination. Unlike oligodendrocytes, astrocytes do not have a high metabolic requirement for iron. However, these cells are in close contact with blood vessel and have a strong iron transport capacity. In several pathological situations, changes in iron homoeostasis result in altered cellular iron distribution and accumulation and oxidative stress. In inflammatory demyelinating diseases such as multiple sclerosis, reactive astrocytes accumulate iron and upregulate iron efflux and influx molecules, which suggest that they are outfitted to take up and safely recycle iron. In this review, we will discuss the participation of oligodendrocytes and astrocytes in CNS iron homeostasis. Understanding the molecular mechanisms of iron uptake, storage, and efflux in oligodendrocytes and astrocytes is necessary for planning effective strategies for iron management during CNS development as well as for the treatment of demyelinating diseases.
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Affiliation(s)
- Veronica T Cheli
- Department of Pharmacology and Toxicology, Jacobs School of Medicine and Biomedical Sciences, Hunter James Kelly Research Institute, The State University of New York, University at Buffalo, Buffalo, New York, United States
| | | | - Pablo M Paez
- Department of Pharmacology and Toxicology, Jacobs School of Medicine and Biomedical Sciences, Hunter James Kelly Research Institute, The State University of New York, University at Buffalo, Buffalo, New York, United States
| | - Juana M Pasquini
- CONICET, Instituto de Química y Fisicoquímica Biológicas, Universidad de Buenos Aires, Buenos Aires, Argentina
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103
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Pacholko AG, Wotton CA, Bekar LK. Astrocytes-The Ultimate Effectors of Long-Range Neuromodulatory Networks? Front Cell Neurosci 2020; 14:581075. [PMID: 33192327 PMCID: PMC7554522 DOI: 10.3389/fncel.2020.581075] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Accepted: 09/07/2020] [Indexed: 11/21/2022] Open
Abstract
It was long thought that astrocytes, given their lack of electrical signaling, were not involved in communication with neurons. However, we now know that one astrocyte on average maintains and regulates the extracellular neurotransmitter and potassium levels of more than 140,000 synapses, both excitatory and inhibitory, within their individual domains, and form a syncytium that can propagate calcium waves to affect distant cells via release of “gliotransmitters” such as glutamate, ATP, or adenosine. Neuromodulators can affect signal-to-noise and frequency transmission within cortical circuits by effects on inhibition, allowing for the filtering of relevant vs. irrelevant stimuli. Moreover, synchronized “resting” and desynchronized “activated” brain states are gated by short bursts of high-frequency neuromodulatory activity, highlighting the need for neuromodulation that is robust, rapid, and far-reaching. As many neuromodulators are released in a volume manner where degradation/uptake and the confines of the complex CNS limit diffusion distance, we ask the question—are astrocytes responsible for rapidly extending neuromodulator actions to every synapse? Neuromodulators are known to influence transitions between brain states, leading to control over plasticity, responses to salient stimuli, wakefulness, and sleep. These rapid and wide-spread state transitions demand that neuromodulators can simultaneously influence large and diverse regions in a manner that should be impossible given the limitations of simple diffusion. Intriguingly, astrocytes are ideally situated to amplify/extend neuromodulator effects over large populations of synapses given that each astrocyte can: (1) ensheath a large number of synapses; (2) release gliotransmitters (glutamate/ATP/adenosine) known to affect inhibition; (3) regulate extracellular potassium that can affect excitability and excitation/inhibition balance; and (4) express receptors for all neuromodulators. In this review article, we explore the hypothesis that astrocytes extend and amplify neuromodulatory influences on neuronal networks via alterations in calcium dynamics, the release of gliotransmitters, and potassium homeostasis. Given that neuromodulatory networks are at the core of our sleep-wake cycle and behavioral states, and determine how we interact with our environment, this review article highlights the importance of basic astrocyte function in homeostasis, general cognition, and psychiatric disorders.
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Affiliation(s)
- Anthony G Pacholko
- Department of Anatomy, Physiology, and Pharmacology, University of Saskatchewan, Saskatoon, SK, Canada
| | - Caitlin A Wotton
- Department of Anatomy, Physiology, and Pharmacology, University of Saskatchewan, Saskatoon, SK, Canada
| | - Lane K Bekar
- Department of Anatomy, Physiology, and Pharmacology, University of Saskatchewan, Saskatoon, SK, Canada
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104
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Rajdev K, Mehan S. Neuroprotective Methodologies of Co-Enzyme Q10 Mediated Brain Hemorrhagic Treatment: Clinical and Pre-Clinical Findings. CNS & NEUROLOGICAL DISORDERS-DRUG TARGETS 2020; 18:446-465. [PMID: 31187715 DOI: 10.2174/1871527318666190610101144] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2019] [Revised: 04/22/2019] [Accepted: 05/07/2019] [Indexed: 12/13/2022]
Abstract
Cerebral brain hemorrhage is associated with the highest mortality and morbidity despite only constituting approximately 10-15% of all strokes classified into intracerebral and intraventricular hemorrhage where most of the patients suffer from impairment in memory, weakness or paralysis in arms or legs, headache, fatigue, gait abnormality and cognitive dysfunctions. Understanding molecular pathology and finding the worsening cause of hemorrhage will lead to explore the therapeutic interventions that could prevent and cure the disease. Mitochondrial ETC-complexes dysfunction has been found to increase neuroinflammatory cytokines, oxidative free radicals, excitotoxicity, neurotransmitter and energy imbalance that are the key neuropathological hallmarks of cerebral hemorrhage. Coenzyme Q10 (CoQ10), as a part of the mitochondrial respiratory chain can effectively restore these neuronal dysfunctions by preventing the opening of mitochondrial membrane transition pore, thereby counteracting cell death events as well as exerts an anti-inflammatory effect by influencing the expression of NF-kB1 dependent genes thus preventing the neuroinflammation and energy restoration. Due to behavior and biochemical heterogeneity in post cerebral brain hemorrhagic pattern different preclinical autologous blood injection models are required to precisely investigate the forthcoming therapeutic strategies. Despite emerging pre-clinical research and resultant large clinical trials for promising symptomatic treatments, there are very less pharmacological interventions demonstrated to improve post operative condition of patients where intensive care is required. Therefore, in current review, we explore the disease pattern, clinical and pre-clinical interventions under investigation and neuroprotective methodologies of CoQ10 precursors to ameliorate post brain hemorrhagic conditions.
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Affiliation(s)
- Kajal Rajdev
- Department of Pharmacology, ISF College of Pharmacy, Moga-142001, Punjab, India
| | - Sidharth Mehan
- Department of Pharmacology, ISF College of Pharmacy, Moga-142001, Punjab, India
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105
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Kumar M, Adeluyi A, Anderson EL, Turner JR. Glial cells as therapeutic targets for smoking cessation. Neuropharmacology 2020; 175:108157. [PMID: 32461156 PMCID: PMC7791555 DOI: 10.1016/j.neuropharm.2020.108157] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Revised: 05/19/2020] [Accepted: 05/20/2020] [Indexed: 12/17/2022]
Abstract
Smoking remains the leading cause of morbidity and mortality in the United States, with less than 5% of smokers attempting to quit succeeding. This low smoking cessation success rate is thought to be due to the long-term adaptations and alterations in synaptic plasticity that occur following chronic nicotine exposure and withdrawal. Glial cells have recently emerged as active players in the development of dependence phenotypes due to their roles in modulating neuronal functions and synaptic plasticity. Fundamental studies have demonstrated that microglia and astrocytes are crucial for synapse formation and elimination in the developing brain, likely contributing to why glial dysfunction is implicated in numerous neurological and psychiatric disorders. Recently, there is increasing evidence for the involvement of glial cells in drug dependence and its associated behavioral manifestations. This review summarizes the newly evaluated role of microglia and astrocytes as molecular drivers of nicotine dependence and withdrawal phenotypes. This article is part of the special issue on 'Contemporary Advances in Nicotine Neuropharmacology.
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Affiliation(s)
- Mohit Kumar
- Department of Pharmaceutical Sciences, University of Kentucky College of Pharmacy, Lexington, KY, USA.
| | - Adewale Adeluyi
- Department of Pharmaceutical Sciences, University of Kentucky College of Pharmacy, Lexington, KY, USA; Ann Romney Center for Neurologic Disease, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.
| | - Erin L Anderson
- Department of Drug Discovery and Biomedical Sciences, South Carolina College of Pharmacy, University of South Carolina, Columbia, USA.
| | - Jill R Turner
- Department of Pharmaceutical Sciences, University of Kentucky College of Pharmacy, Lexington, KY, USA.
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106
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Ouali Alami N, Tang L, Wiesner D, Commisso B, Bayer D, Weishaupt J, Dupuis L, Wong P, Baumann B, Wirth T, Boeckers TM, Yilmazer-Hanke D, Ludolph A, Roselli F. Multiplexed chemogenetics in astrocytes and motoneurons restore blood-spinal cord barrier in ALS. Life Sci Alliance 2020; 3:3/11/e201900571. [PMID: 32900826 PMCID: PMC7479971 DOI: 10.26508/lsa.201900571] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Revised: 08/24/2020] [Accepted: 08/31/2020] [Indexed: 12/20/2022] Open
Abstract
Chemogenetic motoneuron excitation and astrocyte GPCR-Gi signaling restore blood–spinal cord barrier, disrupted in four ALS mouse models, revealing its role in disease progression but not initiation. Blood–spinal cord barrier (BSCB) disruption is thought to contribute to motoneuron (MN) loss in amyotrophic lateral sclerosis (ALS). It is currently unclear whether impairment of the BSCB is the cause or consequence of MN dysfunction and whether its restoration may be directly beneficial. We revealed that SOD1G93A, FUSΔNLS, TDP43G298S, and Tbk1+/− ALS mouse models commonly shared alterations in the BSCB, unrelated to motoneuron loss. We exploit PSAM/PSEM chemogenetics in SOD1G93A mice to demonstrate that the BSCB is rescued by increased MN firing, whereas inactivation worsens it. Moreover, we use DREADD chemogenetics, alone or in multiplexed form, to show that activation of Gi signaling in astrocytes restores BSCB integrity, independently of MN firing, with no effect on MN disease markers and dissociating them from BSCB disruption. We show that astrocytic levels of the BSCB stabilizers Wnt7a and Wnt5a are decreased in SOD1G93A mice and strongly enhanced by Gi signaling, although further decreased by MN inactivation. Thus, we demonstrate that BSCB impairment follows MN dysfunction in ALS pathogenesis but can be reversed by Gi-induced expression of astrocytic Wnt5a/7a.
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Affiliation(s)
- Najwa Ouali Alami
- Department of Neurology, Ulm University, Ulm, Germany.,International Graduate School in Molecular Medicine Ulm, Ulm, Germany.,Department of Neurology, Clinical Neuroanatomy, Ulm University, Ulm, Germany
| | - Linyun Tang
- Department of Neurology, Ulm University, Ulm, Germany
| | - Diana Wiesner
- Department of Neurology, Ulm University, Ulm, Germany.,German Center for Neurodegenerative Diseases (DZNE), Ulm, Germany
| | | | - David Bayer
- Department of Neurology, Ulm University, Ulm, Germany.,CEMMA Graduate School, Ulm University, Ulm, Germany
| | | | - Luc Dupuis
- Inserm U1118, Mécanismes Centraux et Périphériques de la Neurodégénérescence; Université de Strasbourg, Faculté de Médecine, Strasbourg, France
| | - Phillip Wong
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.,Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Bernd Baumann
- Institute of Physiological Chemistry, Ulm University, Ulm, Germany
| | - Thomas Wirth
- Institute of Physiological Chemistry, Ulm University, Ulm, Germany
| | - Tobias M Boeckers
- German Center for Neurodegenerative Diseases (DZNE), Ulm, Germany.,Department of Anatomy and Cell Biology, Ulm University, Ulm, Germany
| | | | - Albert Ludolph
- Department of Neurology, Ulm University, Ulm, Germany.,German Center for Neurodegenerative Diseases (DZNE), Ulm, Germany
| | - Francesco Roselli
- Department of Neurology, Ulm University, Ulm, Germany .,German Center for Neurodegenerative Diseases (DZNE), Ulm, Germany
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107
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Ling YTT, Pease ME, Jefferys JL, Kimball EC, Quigley HA, Nguyen TD. Pressure-Induced Changes in Astrocyte GFAP, Actin, and Nuclear Morphology in Mouse Optic Nerve. Invest Ophthalmol Vis Sci 2020; 61:14. [PMID: 32910133 PMCID: PMC7488631 DOI: 10.1167/iovs.61.11.14] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Accepted: 08/12/2020] [Indexed: 12/17/2022] Open
Abstract
Purpose To conduct quantitative analysis of astrocytic glial fibrillary acidic protein (GFAP), actin and nuclei distribution in mouse optic nerve (ON) and investigate changes in the measured features after 3 days of ocular hypertension (OHT). Method Serial cross-sections of 3-day microbead-induced OHT and control ONs were fluorescently labelled and imaged using confocal microscope. Eighteen structural features were measured from the acquired images, including GFAP coverage, actin area fraction, process thickness, and aspect ratio of cell nucleus. The measured features were analyzed for variations with axial locations along ON and radial zones transverse to ON, as well as for the correlations with degree of intraocular pressure (IOP) change. Results The most significant changes in structural features after 3-day OHT occurred in the unmyelinated ON region (R1), and the changes were greater with greater IOP elevation. Although the GFAP, actin, axonal, and ON areas all increased in 3-day OHT ONs in R1 (P ≤ 0.004 for all), the area fraction of GFAP actually decreased (P = 0.02), the actin area fraction was stable and individual axon compartments were unchanged in size. Within R1, the number of nuclear clusters increased (P < 0.001), but the mean size of nuclear clusters was smaller (P = 0.02) and the clusters became rounder (P < 0.001). In all cross-sections of control ONs, astrocytic processes were thickest in the rim zone compared with the central and peripheral zones (P ≤ 0.002 for both), whereas the overall process width in R1 decreased after 3 days of OHT (P < 0.001). Conclusions The changes in structure elucidated IOP-generated alterations that underlie astrocyte mechanotranslational responses relevant to glaucoma.
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Affiliation(s)
- Yik Tung Tracy Ling
- Department of Mechanical Engineering, The Johns Hopkins University, Baltimore, Maryland, United States
| | - Mary E. Pease
- Wilmer Ophthalmological Institute, Johns Hopkins School of Medicine, Baltimore, Maryland, United States
| | - Joan L. Jefferys
- Wilmer Ophthalmological Institute, Johns Hopkins School of Medicine, Baltimore, Maryland, United States
| | - Elizabeth C. Kimball
- Wilmer Ophthalmological Institute, Johns Hopkins School of Medicine, Baltimore, Maryland, United States
| | - Harry A. Quigley
- Wilmer Ophthalmological Institute, Johns Hopkins School of Medicine, Baltimore, Maryland, United States
| | - Thao D. Nguyen
- Department of Mechanical Engineering, The Johns Hopkins University, Baltimore, Maryland, United States
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108
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Lin B, Wang Y, Zhang P, Yuan Y, Zhang Y, Chen G. Gut microbiota regulates neuropathic pain: potential mechanisms and therapeutic strategy. J Headache Pain 2020; 21:103. [PMID: 32807072 PMCID: PMC7433133 DOI: 10.1186/s10194-020-01170-x] [Citation(s) in RCA: 66] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Accepted: 08/10/2020] [Indexed: 02/08/2023] Open
Abstract
Neuropathic pain (NP) is a sustained and nonreversible condition characterized by long-term devastating physical and psychological damage. Therefore, it is urgent to identify an effective treatment for NP. Unfortunately, the precise pathogenesis of NP has not been elucidated. Currently, the microbiota-gut-brain axis has drawn increasing attention, and the emerging role of gut microbiota is investigated in numerous diseases including NP. Gut microbiota is considered as a pivotal regulator in immune, neural, endocrine, and metabolic signaling pathways, which participates in forming a complex network to affect the development of NP directly or indirectly. In this review, we conclude the current understanding of preclinical and clinical findings regarding the role of gut microbiota in NP and provide a novel therapeutic method for pain relief by medication and dietary interventions.
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Affiliation(s)
- Binbin Lin
- Department of Anesthesiology, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, 3 Qingchun East Road, Zhejiang, 310016, Hangzhou, China
| | - Yuting Wang
- Department of Anesthesiology, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, 3 Qingchun East Road, Zhejiang, 310016, Hangzhou, China
| | - Piao Zhang
- Department of Anesthesiology, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, 3 Qingchun East Road, Zhejiang, 310016, Hangzhou, China
| | - Yanyan Yuan
- Department of Anesthesiology, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, 3 Qingchun East Road, Zhejiang, 310016, Hangzhou, China
| | - Ying Zhang
- Department of Anesthesiology, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, 3 Qingchun East Road, Zhejiang, 310016, Hangzhou, China
| | - Gang Chen
- Department of Anesthesiology, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, 3 Qingchun East Road, Zhejiang, 310016, Hangzhou, China.
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109
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Woo J, Jang MW, Lee J, Koh W, Mikoshiba K, Lee CJ. The molecular mechanism of synaptic activity-induced astrocytic volume transient. J Physiol 2020; 598:4555-4572. [PMID: 32706443 DOI: 10.1113/jp279741] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Accepted: 07/20/2020] [Indexed: 12/16/2022] Open
Abstract
KEY POINTS Neuronal activity causes astrocytic volume change via K+ uptake through TREK-1 containing two-pore domain potassium channels. The volume transient is terminated by Cl- efflux through the Ca2+ -activated anion channel BEST1. The source of the Ca2+ required to open BEST1 appears to be the stretch-activated TRPA1 channel. Intense neuronal activity is synaptically coupled with a physical change in astrocytes via volume transients. ABSTRACT The brain volume changes dynamically and transiently upon intense neuronal activity through a tight regulation of ion concentrations and water movement across the plasma membrane of astrocytes. We have recently demonstrated that an intense neuronal activity and subsequent astrocytic AQP4-dependent volume transient are critical for synaptic plasticity and memory. We have also pharmacologically demonstrated a functional coupling between synaptic activity and the astrocytic volume transient. However, the precise molecular mechanisms of how intense neuronal activity and the astrocytic volume transient are coupled remain unclear. Here we utilized an intrinsic optical signal imaging technique combined with fluorescence imaging using ion sensitive dyes and molecular probes and electrophysiology to investigate the detailed molecular mechanisms in genetically modified mice. We report that a brief synaptic activity induced by a train stimulation (20 Hz, 1 s) causes a prolonged astrocytic volume transient (80 s) via K+ uptake through TREK-1 containing two-pore domain potassium (K2P) channels, but not Kir4.1 or NKCC1. This volume change is terminated by Cl- efflux through the Ca2+ -activated anion channel BEST1, but not the volume-regulated anion channel TTYH. The source of the Ca2+ required to open BEST1 appears to be the stretch-activated TRPA1 channel in astrocytes, but not IP3 R2. In summary, our study identifies several important astrocytic ion channels (AQP4, TREK-1, BEST1, TRPA1) as the key molecules leading to the neuronal activity-dependent volume transient in astrocytes. Our findings reveal new molecular and cellular mechanisms for the synaptic coupling of intense neuronal activity with a physical change in astrocytes via volume transients.
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Affiliation(s)
- Junsung Woo
- Center for Glia-Neuron Interaction, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea
| | - Minwoo Wendy Jang
- KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul, 02841, Republic of Korea.,Center for Cognition and Sociality, Institute for Basic Science (IBS), Daejeon, 34126, Republic of Korea
| | - Jaekwang Lee
- Center for Glia-Neuron Interaction, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea
| | - Wuhyun Koh
- Center for Cognition and Sociality, Institute for Basic Science (IBS), Daejeon, 34126, Republic of Korea.,Department of Neuroscience, Division of Bio-Medical Science & Technology, KIST School, Korea University of Science and Technology (UST), Seoul, 02792, Republic of Korea
| | - Katsuhiko Mikoshiba
- Laboratory for Developmental Biology, RIKEN Brain Science Institute, Hirosawa 2-1, Wako, Saitama, 351-0198, Japan
| | - C Justin Lee
- Center for Glia-Neuron Interaction, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea.,KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul, 02841, Republic of Korea.,Center for Cognition and Sociality, Institute for Basic Science (IBS), Daejeon, 34126, Republic of Korea.,Department of Neuroscience, Division of Bio-Medical Science & Technology, KIST School, Korea University of Science and Technology (UST), Seoul, 02792, Republic of Korea
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110
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Gómez-Budia M, Konttinen H, Saveleva L, Korhonen P, Jalava PI, Kanninen KM, Malm T. Glial smog: Interplay between air pollution and astrocyte-microglia interactions. Neurochem Int 2020; 136:104715. [DOI: 10.1016/j.neuint.2020.104715] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 03/05/2020] [Accepted: 03/06/2020] [Indexed: 12/15/2022]
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111
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Turko P, Groberman K, Browa F, Cobb S, Vida I. Differential Dependence of GABAergic and Glutamatergic Neurons on Glia for the Establishment of Synaptic Transmission. Cereb Cortex 2020; 29:1230-1243. [PMID: 29425353 DOI: 10.1093/cercor/bhy029] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2017] [Accepted: 01/17/2018] [Indexed: 11/14/2022] Open
Abstract
In the mammalian cortex, GABAergic and glutamatergic neurons represent 2 major neuronal classes, which establish inhibitory and excitatory synapses, respectively. Despite differences in their anatomy, physiology and developmental origin, both cell types require support from glial cells, particularly astrocytes, for their growth and survival. Recent experiments indicate that glutamatergic neurons also depend on astrocytes for synapse formation. However, it is not clear if the same holds true for GABAergic neurons. By studying highly pure GABAergic cell cultures, established through fluorescent activated cell sorting, we find that purified GABAergic neurons are smaller and have reduced survival, nevertheless they establish robust synaptic transmission in the absence of glia. Support from glial cells reverses morphological and survival deficits, but does little to alter synaptic transmission. In contrast, in cultures of purified glutamatergic neurons, morphological development, survival and synaptic transmission are collectively dependent on glial support. Thus, our results demonstrate a fundamental difference in the way GABAergic and glutamatergic neurons depend on glia for the establishment of synaptic transmission, a finding that has important implications for our understanding of how neuronal networks develop.
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Affiliation(s)
- Paul Turko
- Institute for Integrative Neuroanatomy, NeuroCure Cluster of Excellence, Charité-Universitätsmedizin Berlin, Berlin, Germany.,Institute of Neuroscience and Psychology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Keenan Groberman
- Institute for Integrative Neuroanatomy, NeuroCure Cluster of Excellence, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Ferdinand Browa
- Institute for Integrative Neuroanatomy, NeuroCure Cluster of Excellence, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Stuart Cobb
- Institute of Neuroscience and Psychology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK.,Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK
| | - Imre Vida
- Institute for Integrative Neuroanatomy, NeuroCure Cluster of Excellence, Charité-Universitätsmedizin Berlin, Berlin, Germany
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112
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de Montgolfier O, Thorin-Trescases N, Thorin E. Pathological Continuum From the Rise in Pulse Pressure to Impaired Neurovascular Coupling and Cognitive Decline. Am J Hypertens 2020; 33:375-390. [PMID: 32202623 PMCID: PMC7188799 DOI: 10.1093/ajh/hpaa001] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Revised: 12/11/2019] [Accepted: 03/03/2020] [Indexed: 12/12/2022] Open
Abstract
The "biomechanical hypothesis" stipulates that with aging, the cumulative mechanical damages to the cerebral microvasculature, magnified by risk factors for vascular diseases, contribute to a breach in cerebral homeostasis producing neuronal losses. In other words, vascular dysfunction affects brain structure and function, and leads to cognitive failure. This is gathered under the term Vascular Cognitive Impairment and Dementia (VCID). One of the main culprits in the occurrence of cognitive decline could be the inevitable rise in arterial pulse pressure due to the age-dependent stiffening of large conductance arteries like the carotids, which in turn, could accentuate the penetration of the pulse pressure wave deeper into the fragile microvasculature of the brain and damage it. In this review, we will discuss how and why the vascular and brain cells communicate and are interdependent, describe the deleterious impact of a vascular dysfunction on brain function in various neurodegenerative diseases and even of psychiatric disorders, and the potential chronic deleterious effects of the pulsatile blood pressure on the cerebral microcirculation. We will also briefly review data from antihypertensive clinical trial aiming at improving or delaying dementia. Finally, we will debate how the aging process, starting early in life, could determine our sensitivity to risk factors for vascular diseases, including cerebral diseases, and the trajectory to VCID.
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Affiliation(s)
- Olivia de Montgolfier
- Faculty of Medicine, Department of Pharmacology and Physiology, Université de Montréal, Montreal, Quebec, Canada
- Montreal Heart Institute, Research Center, Montreal, Quebec, Canada
| | | | - Eric Thorin
- Faculty of Medicine, Department of Pharmacology and Physiology, Université de Montréal, Montreal, Quebec, Canada
- Montreal Heart Institute, Research Center, Montreal, Quebec, Canada
- Faculty of Medicine, Department of Surgery, Université de Montréal, Montreal, Quebec, Canada
- Correspondence: Eric Thorin ()
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113
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Heller JP, Odii T, Zheng K, Rusakov DA. Imaging tripartite synapses using super-resolution microscopy. Methods 2020; 174:81-90. [PMID: 31153907 PMCID: PMC7144327 DOI: 10.1016/j.ymeth.2019.05.024] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Revised: 05/03/2019] [Accepted: 05/28/2019] [Indexed: 01/02/2023] Open
Abstract
Astroglia are vital facilitators of brain development, homeostasis, and metabolic support. In addition, they are also essential to the formation and regulation of synaptic circuits. Due to the extraordinary complex, nanoscopic morphology of astrocytes, the underlying cellular mechanisms have been poorly understood. In particular, fine astrocytic processes that can be found in the vicinity of synapses have been difficult to study using traditional imaging techniques. Here, we describe a 3D three-colour super-resolution microscopy approach to unravel the nanostructure of tripartite synapses. The method is based on the SMLM technique direct stochastic optical reconstruction microscopy (dSTORM) which uses conventional fluorophore-labelled antibodies. This approach enables reconstructing the nanoscale localisation of individual astrocytic glutamate transporter (GLT-1) molecules surrounding presynaptic (bassoon) and postsynaptic (Homer1) protein localisations in fixed mouse brain sections. However, the technique is readily adaptable to other types of targets and tissues.
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Affiliation(s)
- Janosch Peter Heller
- UCL Queen Square Institute of Neurology, University College London, London, United Kingdom; FutureNeuro Research Centre, Royal College of Surgeons in Ireland, Dublin, Ireland.
| | - Tuamoru Odii
- UCL Queen Square Institute of Neurology, University College London, London, United Kingdom; Department of Physiology, Faculty of Basic Medical Sciences, Alex Ekwueme Federal University Ndufu-Alike Ikwo, PMB 1010 Abakaliki, Nigeria
| | - Kaiyu Zheng
- UCL Queen Square Institute of Neurology, University College London, London, United Kingdom
| | - Dmitri A Rusakov
- UCL Queen Square Institute of Neurology, University College London, London, United Kingdom.
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114
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Abrahamson EE, Ikonomovic MD. Brain injury-induced dysfunction of the blood brain barrier as a risk for dementia. Exp Neurol 2020; 328:113257. [PMID: 32092298 DOI: 10.1016/j.expneurol.2020.113257] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2019] [Revised: 01/31/2020] [Accepted: 02/20/2020] [Indexed: 02/06/2023]
Abstract
The blood-brain barrier (BBB) is a complex and dynamic physiological interface between brain parenchyma and cerebral vasculature. It is composed of closely interacting cells and signaling molecules that regulate movement of solutes, ions, nutrients, macromolecules, and immune cells into the brain and removal of products of normal and abnormal brain cell metabolism. Dysfunction of multiple components of the BBB occurs in aging, inflammatory diseases, traumatic brain injury (TBI, severe or mild repetitive), and in chronic degenerative dementing disorders for which aging, inflammation, and TBI are considered risk factors. BBB permeability changes after TBI result in leakage of serum proteins, influx of immune cells, perivascular inflammation, as well as impairment of efflux transporter systems and accumulation of aggregation-prone molecules involved in hallmark pathologies of neurodegenerative diseases with dementia. In addition, cerebral vascular dysfunction with persistent alterations in cerebral blood flow and neurovascular coupling contribute to brain ischemia, neuronal degeneration, and synaptic dysfunction. While the idea of TBI as a risk factor for dementia is supported by many shared pathological features, it remains a hypothesis that needs further testing in experimental models and in human studies. The current review focusses on pathological mechanisms shared between TBI and neurodegenerative disorders characterized by accumulation of pathological protein aggregates, such as Alzheimer's disease and chronic traumatic encephalopathy. We discuss critical knowledge gaps in the field that need to be explored to clarify the relationship between TBI and risk for dementia and emphasize the need for longitudinal in vivo studies using imaging and biomarkers of BBB dysfunction in people with single or multiple TBI.
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Affiliation(s)
- Eric E Abrahamson
- Geriatric Research Education and Clinical Center, VA Pittsburgh Healthcare System, University of Pittsburgh, Pittsburgh, PA, United States; Department of Neurology, University of Pittsburgh, Pittsburgh, PA, United States
| | - Milos D Ikonomovic
- Geriatric Research Education and Clinical Center, VA Pittsburgh Healthcare System, University of Pittsburgh, Pittsburgh, PA, United States; Department of Neurology, University of Pittsburgh, Pittsburgh, PA, United States; Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, United States.
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115
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Yalçın GD, Colak M. SIRT4 prevents excitotoxicity via modulating glutamate metabolism in glioma cells. Hum Exp Toxicol 2020; 39:938-947. [DOI: 10.1177/0960327120907142] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Excitotoxicity is the presence of excessive glutamate, which is normally taken up by glutamate transporters on astrocytes. Glutamate transporter 1 (GLT-1) is the major transporter on glia cells clearing more than 90% of the glutamate. Sirtuin 4 (SIRT4) is a mitochondrial sirtuin which is expressed in the brain. Previously, it was shown that loss of SIRT4 leads to a more severe reaction to kainic acid, an excitotoxic agent, and also decreased GLT-1 expression in the brain. In this study, we aimed to investigate whether overexpression of SIRT4 is protective against excitotoxicity in glia cells. We overexpressed SIRT4 in A172 glioma cell line and treated with kainic acid in order to induce excitotoxicity. We observed that SIRT4 overexpression increased the cell viability after kainic acid treatment. In addition, reduced glutamate was detected in glutamate assay with overexpression of SIRT4 after kainic acid treatment since SIRT4 decreased cell death by preventing excitotoxicity. Our results show that overexpression of SIRT4 increased the protein levels of GLT-1 and glutamate dehydrogenase (GDH) after kainic acid (KA) treatment so that excess glutamate can be absorbed. However, overexpression of SIRT4 decreased glutamine synthetase (GS) levels. These results demonstrate that, by inhibiting GS, SIRT4 prevents glutamine formation, which will be converted to glutamate in neurons. SIRT4 prevents excitotoxicity via upregulating glutamate metabolism. Finally, our results may show that SIRT4 might prevent excitotoxicity and related cell death via reducing GS expression and upregulating GLT-1 and GDH levels. Therefore, it is important to develop therapeutics against excitotoxicity through SIRT4-related pathways in the cell.
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Affiliation(s)
- G Dönmez Yalçın
- Faculty of Medicine, Department of Medical Biology, Adnan Menderes University, Aydin, Turkey
| | - M Colak
- Faculty of Medicine, Department of Medical Biology, Adnan Menderes University, Aydin, Turkey
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116
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Yadav KS, Sharma S, Londhe VY. Bio-tactics for neuroprotection of retinal ganglion cells in the treatment of glaucoma. Life Sci 2020; 243:117303. [DOI: 10.1016/j.lfs.2020.117303] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Revised: 01/03/2020] [Accepted: 01/12/2020] [Indexed: 01/01/2023]
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117
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Hartnell D, Andrews W, Smith N, Jiang H, McAllum E, Rajan R, Colbourne F, Fitzgerald M, Lam V, Takechi R, Pushie MJ, Kelly ME, Hackett MJ. A Review of ex vivo Elemental Mapping Methods to Directly Image Changes in the Homeostasis of Diffusible Ions (Na +, K +, Mg 2 +, Ca 2 +, Cl -) Within Brain Tissue. Front Neurosci 2020; 13:1415. [PMID: 32038130 PMCID: PMC6987141 DOI: 10.3389/fnins.2019.01415] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Accepted: 12/16/2019] [Indexed: 12/11/2022] Open
Abstract
Diffusible ions (Na+, K+, Mg2+, Ca2+, Cl-) are vital for healthy function of all cells, especially brain cells. Unfortunately, the diffusible nature of these ions renders them difficult to study with traditional microscopy in situ within ex vivo brain tissue sections. This mini-review examines the recent progress in the field, using direct elemental mapping techniques to study ion homeostasis during normal brain physiology and pathophysiology, through measurement of ion distribution and concentration in ex vivo brain tissue sections. The mini-review examines the advantages and limitations of specific techniques: proton induced X-ray emission (PIXE), X-ray fluorescence microscopy (XFM), secondary ion mass spectrometry (SIMS), laser-ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), and the sample preparation requirements to study diffusible ions with these methods.
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Affiliation(s)
- David Hartnell
- School of Molecular and Life Sciences, Faculty of Science and Engineering, Curtin University, Perth, WA, Australia
- Curtin Health Innovation Research Institute, Curtin University, Perth, WA, Australia
- Curtin Institute for Functional Molecules and Interfaces, Curtin University, Perth, WA, Australia
| | - Wendy Andrews
- School of Molecular and Life Sciences, Faculty of Science and Engineering, Curtin University, Perth, WA, Australia
- Curtin Health Innovation Research Institute, Curtin University, Perth, WA, Australia
- Curtin Institute for Functional Molecules and Interfaces, Curtin University, Perth, WA, Australia
| | - Nicole Smith
- School of Molecular Sciences, Faculty of Science, University of Western Australia, Perth, WA, Australia
| | - Haibo Jiang
- School of Molecular Sciences, Faculty of Science, University of Western Australia, Perth, WA, Australia
| | - Erin McAllum
- Melbourne Dementia Research Centre, Florey Institute of Neuroscience and Mental Health, Parkville, VIC, Australia
| | - Ramesh Rajan
- Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
| | - Frederick Colbourne
- Department of Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AL, Canada
- Department of Psychology, Faculty of Arts, University of Alberta, Edmonton, AL, Canada
| | - Melinda Fitzgerald
- Curtin Health Innovation Research Institute, Curtin University, Perth, WA, Australia
- School of Biological Sciences, University of Western Australia, Perth, WA, Australia
- Perron Institute for Neurological and Translational Science, Perth, WA, Australia
| | - Virginie Lam
- Curtin Health Innovation Research Institute, Curtin University, Perth, WA, Australia
- School of Public Health, Faculty of Health Sciences, Curtin University, Perth, WA, Australia
| | - Ryusuke Takechi
- Curtin Health Innovation Research Institute, Curtin University, Perth, WA, Australia
- School of Public Health, Faculty of Health Sciences, Curtin University, Perth, WA, Australia
| | - M. Jake Pushie
- Department of Surgery, College of Medicine, University of Saskatchewan, Saskatoon, SK, Canada
| | - Michael E. Kelly
- Department of Surgery, College of Medicine, University of Saskatchewan, Saskatoon, SK, Canada
| | - Mark J. Hackett
- School of Molecular and Life Sciences, Faculty of Science and Engineering, Curtin University, Perth, WA, Australia
- Curtin Health Innovation Research Institute, Curtin University, Perth, WA, Australia
- Curtin Institute for Functional Molecules and Interfaces, Curtin University, Perth, WA, Australia
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118
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Blockade of Arginine Vasopressin receptors prevents blood-brain barrier breakdown in Experimental Autoimmune Encephalomyelitis. Sci Rep 2020; 10:467. [PMID: 31949182 PMCID: PMC6965180 DOI: 10.1038/s41598-019-57134-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Accepted: 12/16/2019] [Indexed: 01/10/2023] Open
Abstract
The blood-brain barrier (BBB) plays a significant pathophysiological role in multiple sclerosis (MS). Vasopressin (AVP) is released after brain injury and contributes to the inflammatory response. We propose that AVP may be modulating BBB permeability and hence affecting EAE clinical signs. Female Lewis rats were immunized s.c. with guinea-pig brain extract suspended in complete Freund’s adjuvant. Prior to that, animals were subjected to Neurointermediate pituitary lobectomy (NIL) or treated with AVP receptor antagonist (conivaptan). BBB permeability assays were performed. Western blot for claudin-5 and histological analysis were performed in conivaptan treated EAE rats. EAE increase in BBB permeability to Evans blue was reverted by the NIL surgery. AVP receptor blockade reverted the EAE BBB hyperpermeability to Evans blue and 10-kDa FITC-dextran in almost all brain regions. Both, AVP low levels and AVP receptor blockade attenuated EAE clinical signs. Conivaptan reduced perivascular cuffs in EAE rats. A decrease in claudin-5 expression was observed in EAE rats and conivaptan treatment partially restored normal levels. Our data indicate that V1a and V2 AVP receptors can modulate BBB permeability and consequently are involved in the CNS inflammatory process during EAE. Future research is required to characterize the utility of vasopressin antagonist in MS treatment.
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119
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Abstract
The contribution of an impaired astrocytic K+ regulation system to epileptic neuronal hyperexcitability has been increasingly recognized in the last decade. A defective K+ regulation leads to an elevated extracellular K+ concentration ([K+]o). When [K+]o reaches peaks of 10-12 mM, it is strongly associated with seizure initiation during hypersynchronous neuronal activities. On the other hand, reactive astrocytes during a seizure attack restrict influx of K+ across the membrane both passively and actively. In addition to decreased K+ buffering, aberrant Ca2+ signaling and declined glutamate transport have also been observed in astrogliosis in epileptic specimens, precipitating an increased neuronal discharge and induction of seizures. This review aims to provide an overview of experimental findings that implicated astrocytic modulation of extracellular K+ in the mechanism of epileptogenesis.
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Affiliation(s)
- Fushun Wang
- Department of Neurosurgery, Baylor Scott & White Health, Temple, TX, USA; Institute of Brain and Psychological Science, Sichuan Normal University, Chengdu, Sichuan Province, China
| | - Xiaoming Qi
- Department of Neurosurgery, Baylor Scott & White Health, Temple, TX, USA
| | - Jun Zhang
- Department of Neurosurgery, PLA General Hospital, Beijing, China
| | - Jason H Huang
- Department of Neurosurgery, Baylor Scott & White Health; Department of Surgery, Texas A&M University College of Medicine, Temple, TX, USA
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120
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Brain microstructural abnormalities correlate with KCC2 downregulation in refractory epilepsy. Neuroreport 2019; 30:409-414. [PMID: 30817684 DOI: 10.1097/wnr.0000000000001216] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Dysregulations in the expression level of Na-K-Cl cotransporter (NKCC1) and K-Cl cotransporter (KCC2) genes have been detected in the brain tissues of patients with refractory epilepsy. Given the importance of these proteins in the determination of Cl equilibrium potential (ECl), evaluation of the expression changes of these transporters might assist in optimizing the diagnostic approaches and therapeutic strategies. The present investigation evaluates the expression level chloride transporters in polymorphonuclear cells and their correlation with microstructural abnormalities. Thirty cases of drug-resistant epilepsy (confirmed with temporal lobe epilepsy diagnosis) fulfilled the considered inclusion criteria. Cases were divided into two groups, one with a detectable MRI lesion (19 participants; right side) and another with no MRI findings (11 participants). Whole-brain voxel-based analysis was performed on diffusion tensor imaging to measure fractional anisotropy and mean diffusivity; neurite orientation dispersion and density imaging was performed to map neurite density index and orientation dispersion index. Our results indicated that fractional anisotropy and mean diffusivity changed in temporal and extratemporal parts of the brain, whereas the changes in neurite density index and orientation dispersion index were exclusively obvious in the temporal lobe. Molecular studies revealed significantly lower levels of KCC2 expression in patients with epilepsy, a finding that remarkably correlated with microstructural changes as well. Our research showed that downregulation of KCC2 and microstructural abnormalities might contribute to the observed refractoriness in temporal lobe epilepsy.
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121
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Astrocyte control of glutamatergic activity: Downstream effects on serotonergic function and emotional behavior. Neuropharmacology 2019; 166:107914. [PMID: 32045742 DOI: 10.1016/j.neuropharm.2019.107914] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Revised: 11/28/2019] [Accepted: 12/13/2019] [Indexed: 12/15/2022]
Abstract
Major depressive disorder (MDD) is a leading cause of disability worldwide, with a poorly known pathophysiology and sub-optimal treatment, based on serotonin (5-hydroxytryptamine, 5-HT) reuptake inhibitors. We review existing theories on MDD, paying special attention to the role played by the ventral anterior cingulate cortex (vACC) or its rodent equivalent, infralimbic cortex (IL), which tightly control the activity of brainstem monoamine neurons (including raphe 5-HT neurons) via descending afferents. Further, astrocytes regulate excitatory synapse activity via glutamate reuptake through astrocytic transporters EAAT1 and EAAT2 (GLAST and GLT-1 in rodents), and alterations of astrocyte number/function have been reported in MDD patients and suicide victims. We recently assessed the impact of reducing GLAST/GLT-1 function in IL on emotional behavior and serotonergic function in rodents. The acute pharmacological blockade of GLT-1 with dihydrokainate (DHK) in rat IL evoked an antidepressant-like effect mediated by local AMPA-R activation and a subsequent enhancement of serotonergic function. No effects were produced by DHK microinfusion in prelimbic cortex (PrL). In the second model, a moderate small interfering RNAs (siRNA)-induced reduction of GLAST and GLT-1 expression in mouse IL markedly increased local glutamatergic neurotransmission and evoked a depressive-like phenotype (reversed by citalopram and ketamine), and reduced serotonergic function and BDNF expression in cortical/hippocampal areas. As for DHK, siRNA microinfusion in PrL did not evoke behavioral/neurochemical effects. Overall, both studies support a critical role of the astrocyte-neuron communication in the control of excitatory neurotransmission in IL, and subsequently, on emotional behavior, via the downstream associated changes on serotonergic function.
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122
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Liu X, Zheng H. Leptin-Mediated Sympathoexcitation in Obese Rats: Role for Neuron-Astrocyte Crosstalk in the Arcuate Nucleus. Front Neurosci 2019; 13:1217. [PMID: 31803004 PMCID: PMC6877670 DOI: 10.3389/fnins.2019.01217] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Accepted: 10/28/2019] [Indexed: 11/13/2022] Open
Abstract
Introduction Accumulated evidence indicates that obesity is associated with enhanced sympathetic activation. Hypothalamic leptin-mediated signaling may contribute to the exaggerated sympathoexcitation of obesity. The goal of this study was to investigate the "neuron-astrocyte" interaction affecting leptin-mediated sympathoexcitation within the arcuate nucleus (ARCN) of the hypothalamus in obese rats. Methods and Results Obesity was induced by high-fat diet (HFD, 42% of calories from fat) in Sprague Dawley rats. Twelve weeks of HFD produced hyperleptinemia, hyperlipidemia, and insulin resistance. In anesthetized rats, microinjections of leptin into the ARCN induced increases in heart rate (HR), renal sympathetic nerve activity (RSNA), and mean arterial pressure (MAP) in both control and HFD rats. However, microinjections of leptin in HFD rats elicited higher responses of RSNA and arterial pressure than control-fed rats. It also caused the inhibition of astrocytes within the ARCN using an astrocytic metabolic inhibitor, fluorocitrate, and reduced leptin-induced sympathetic activity and blood pressure responses. Moreover, the expression of the leptin receptor in the ARCN of HFD-fed rats was significantly increased compared to rats fed a control diet. Immunohistochemistry analysis revealed leptin receptor localization from both neurons and astrocytes of the ARCN. HFD rats exhibited increased protein expression of glial fibrillary acidic protein (GFAP) in the ARCN. We also found that the expression of astrocyte-specific glutamate transporters and excitatory amino acid transporter 1 (EAAT1) and 2 (EAAT2) were decreased within the ARCN of the HFD rats. In cultured astrocytic C6 cells, 24 h of leptin treatment increased the protein expression of GFAP and reduced the expression of EAAT1 and EAAT2. Conclusion The results suggest that central leptin signaling occurs via neuron-astrocyte interactions in the ARCN and contributing to the exaggerated sympathoexcitation observed in obese rats. The effects may be mediated by the action of leptin on regulating astrocytic glutamate transporters within the ARCN of the hypothalamus.
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Affiliation(s)
- Xuefei Liu
- Division of Basic Biomedical Sciences, Sanford School of Medicine, University of South Dakota, Vermillion, SD, United States
| | - Hong Zheng
- Division of Basic Biomedical Sciences, Sanford School of Medicine, University of South Dakota, Vermillion, SD, United States
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123
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Palpagama TH, Waldvogel HJ, Faull RLM, Kwakowsky A. The Role of Microglia and Astrocytes in Huntington's Disease. Front Mol Neurosci 2019; 12:258. [PMID: 31708741 PMCID: PMC6824292 DOI: 10.3389/fnmol.2019.00258] [Citation(s) in RCA: 122] [Impact Index Per Article: 24.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2019] [Accepted: 10/10/2019] [Indexed: 12/21/2022] Open
Abstract
Huntington's disease (HD) is an autosomal dominant neurodegenerative disease. HD patients present with movement disorders, behavioral and psychiatric symptoms and cognitive decline. This review summarizes the contribution of microglia and astrocytes to HD pathophysiology. Neuroinflammation in the HD brain is characterized by a reactive morphology in these glial cells. Microglia and astrocytes are critical in regulating neuronal activity and maintaining an optimal milieu for neuronal function. Previous studies provide evidence that activated microglia and reactive astrocytes contribute to HD pathology through transcriptional activation of pro-inflammatory genes to perpetuate a chronic inflammatory state. Reactive astrocytes also display functional changes in glutamate and ion homeostasis and energy metabolism. Astrocytic and microglial changes may further contribute to the neuronal death observed with the progression of HD. Importantly, the degree to which these neuroinflammatory changes are detrimental to neurons and contribute to the progression of HD pathology is not well understood. Furthermore, recent observations provide compelling evidence that activated microglia and astrocytes exert a variety of beneficial functions that are essential for limiting tissue damage and preserving neuronal function in the HD brain. Therefore, a better understanding of the neuroinflammatory environment in the brain in HD may lead to the development of targeted and innovative therapeutic opportunities.
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Affiliation(s)
- Thulani H Palpagama
- Centre for Brain Research, Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Henry J Waldvogel
- Centre for Brain Research, Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Richard L M Faull
- Centre for Brain Research, Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Andrea Kwakowsky
- Centre for Brain Research, Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
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124
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Abstract
Leukodystrophies are genetically determined disorders affecting the white matter of the central nervous system. The combination of MRI pattern recognition and next-generation sequencing for the definition of novel disease entities has recently demonstrated that many leukodystrophies are due to the primary involvement and/or mutations in genes selectively expressed by cell types other than the oligodendrocytes, the myelin-forming cells in the brain. This has led to a new definition of leukodystrophies as genetic white matter disorders resulting from the involvement of any white matter structural component. As a result, the research has shifted its main focus from oligodendrocytes to other types of neuroglia. Astrocytes are the housekeeping cells of the nervous system, responsible for maintaining homeostasis and normal brain physiology and to orchestrate repair upon injury. Several lines of evidence show that astrocytic interactions with the other white matter cellular constituents play a primary pathophysiologic role in many leukodystrophies. These are thus now classified as astrocytopathies. This chapter addresses how the crosstalk between astrocytes, other glial cells, axons and non-neural cells are essential for the integrity and maintenance of the white matter in health. It also addresses the current knowledge of the cellular pathomechanisms of astrocytic leukodystrophies, and specifically Alexander disease, vanishing white matter, megalencephalic leukoencephalopathy with subcortical cysts and Aicardi-Goutière Syndrome.
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Affiliation(s)
- M S Jorge
- Department of Pathology, Free University Medical Centre, Amsterdam, The Netherlands
| | - Marianna Bugiani
- Department of Pathology, Free University Medical Centre, Amsterdam, The Netherlands.
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125
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Abstract
Astrocytes are critical for maintaining the homeostasis of the CNS. Increasing evidence suggests that a number of neurological and neuropsychiatric disorders, including chronic pain, may result from astrocyte 'gliopathy'. Indeed, in recent years there has been substantial progress in our understanding of how astrocytes can regulate nociceptive synaptic transmission via neuronal-glial and glial-glial cell interactions, as well as the involvement of spinal and supraspinal astrocytes in the modulation of pain signalling and the maintenance of neuropathic pain. A role of astrocytes in the pathogenesis of chronic itch is also emerging. These developments suggest that targeting the specific pathways that are responsible for astrogliopathy may represent a novel approach to develop therapies for chronic pain and chronic itch.
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126
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Bordone MP, Salman MM, Titus HE, Amini E, Andersen JV, Chakraborti B, Diuba AV, Dubouskaya TG, Ehrke E, Espindola de Freitas A, Braga de Freitas G, Gonçalves RA, Gupta D, Gupta R, Ha SR, Hemming IA, Jaggar M, Jakobsen E, Kumari P, Lakkappa N, Marsh APL, Mitlöhner J, Ogawa Y, Paidi RK, Ribeiro FC, Salamian A, Saleem S, Sharma S, Silva JM, Singh S, Sulakhiya K, Tefera TW, Vafadari B, Yadav A, Yamazaki R, Seidenbecher CI. The energetic brain - A review from students to students. J Neurochem 2019; 151:139-165. [PMID: 31318452 DOI: 10.1111/jnc.14829] [Citation(s) in RCA: 132] [Impact Index Per Article: 26.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Revised: 07/03/2019] [Accepted: 07/08/2019] [Indexed: 12/12/2022]
Abstract
The past 20 years have resulted in unprecedented progress in understanding brain energy metabolism and its role in health and disease. In this review, which was initiated at the 14th International Society for Neurochemistry Advanced School, we address the basic concepts of brain energy metabolism and approach the question of why the brain has high energy expenditure. Our review illustrates that the vertebrate brain has a high need for energy because of the high number of neurons and the need to maintain a delicate interplay between energy metabolism, neurotransmission, and plasticity. Disturbances to the energetic balance, to mitochondria quality control or to glia-neuron metabolic interaction may lead to brain circuit malfunction or even severe disorders of the CNS. We cover neuronal energy consumption in neural transmission and basic ('housekeeping') cellular processes. Additionally, we describe the most common (glucose) and alternative sources of energy namely glutamate, lactate, ketone bodies, and medium chain fatty acids. We discuss the multifaceted role of non-neuronal cells in the transport of energy substrates from circulation (pericytes and astrocytes) and in the supply (astrocytes and microglia) and usage of different energy fuels. Finally, we address pathological consequences of disrupted energy homeostasis in the CNS.
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Affiliation(s)
- Melina Paula Bordone
- Facultad de Farmacia y Bioquímica, Instituto de Investigaciones Farmacológicas (ININFA), Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Mootaz M Salman
- Department of Cell Biology, Harvard Medical School, and Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, Massachusetts, USA
| | - Haley E Titus
- Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Elham Amini
- Department of Medicine, University Kebangsaan Malaysia Medical Centre (HUKM), Cheras, Kuala Lumpur, Malaysia
| | - Jens V Andersen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | | | - Artem V Diuba
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia
| | - Tatsiana G Dubouskaya
- Institute of Biophysics and Cell Engineering, National Academy of Sciences of Belarus, Minsk, Belarus
| | - Eric Ehrke
- Centre for Biomolecular Interactions, University of Bremen, Bremen, Germany
| | - Andiara Espindola de Freitas
- Neurobiology Section, Biological Sciences Division, University of California, San Diego, La Jolla, California, USA
| | | | | | | | - Richa Gupta
- CSIR-Indian Institute of Toxicology Research, Lucknow, India
| | - Sharon R Ha
- Baylor College of Medicine, Houston, Texas, USA
| | - Isabel A Hemming
- Brain Growth and Disease Laboratory, The Harry Perkins Institute of Medical Research, Nedlands, Western Australia, Australia.,School of Medicine and Pharmacology, The University of Western Australia, Crawley, Australia
| | - Minal Jaggar
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, India
| | - Emil Jakobsen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Punita Kumari
- Defense Institute of Physiology and allied sciences, Defense Research and Development Organization, Timarpur, Delhi, India
| | - Navya Lakkappa
- Department of Pharmacology, JSS college of Pharmacy, Ooty, India
| | - Ashley P L Marsh
- Bruce Lefroy Centre for Genetic Health Research, Murdoch Children's Research Institute, Royal Children's Hospital, Parkville, Victoria, Australia
| | - Jessica Mitlöhner
- Department of Neurochemistry and Molecular Biology, Leibniz Institute for Neurobiology Magdeburg, Magdeburg, Germany
| | - Yuki Ogawa
- The Jikei University School of Medicine, Minato-ku, Tokyo, Japan
| | | | | | - Ahmad Salamian
- Department of Molecular and Cellular Neurobiology, Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland
| | - Suraiya Saleem
- CSIR-Indian Institute of Chemical Biology, Kolkata, India
| | - Sorabh Sharma
- Department of Pharmacy, Birla Institute of Technology and Science, Pilani, Rajasthan, India
| | - Joana M Silva
- Life and Health Sciences Research Institute (ICVS), Medical School, University of Minho, Braga, Portugal
| | - Shripriya Singh
- CSIR-Indian Institute of Toxicology Research, Lucknow, India
| | - Kunjbihari Sulakhiya
- Department of Pharmacy, Indira Gandhi National Tribal University, Amarkantak, India
| | - Tesfaye Wolde Tefera
- School of Biomedical Sciences, The University of Queensland, Brisbane, Queensland, Australia
| | - Behnam Vafadari
- Institute of environmental medicine, UNIKA-T, Technical University of Munich, Munich, Germany
| | - Anuradha Yadav
- CSIR-Indian Institute of Toxicology Research, Lucknow, India
| | - Reiji Yamazaki
- Tokyo University of Pharmacy and Life Sciences, Tokyo, Japan.,Center for Behavioral Brain Sciences (CBBS), Otto von Guericke University, Magdeburg, Germany
| | - Constanze I Seidenbecher
- Department of Neurochemistry and Molecular Biology, Leibniz Institute for Neurobiology Magdeburg, Magdeburg, Germany.,Center for Behavioral Brain Sciences (CBBS), Otto von Guericke University, Magdeburg, Germany
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127
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Kim JE, Kang TC. PKC, AKT and ERK1/2-Mediated Modulations of PARP1, NF-κB and PEA15 Activities Distinctly Regulate Regional Specific Astroglial Responses Following Status Epilepticus. Front Mol Neurosci 2019; 12:180. [PMID: 31396050 PMCID: PMC6667551 DOI: 10.3389/fnmol.2019.00180] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Accepted: 07/09/2019] [Indexed: 01/04/2023] Open
Abstract
Status epilepticus (SE, a prolonged seizure activity) leads to reactive astrogliosis and astroglial apoptosis in the regional specific manners, independent of hemodynamics. Poly(ADP-ribose) polymerase-1 (PARP1) activity is relevant to these distinct astroglial responses. Since various regulatory signaling molecules beyond PARP1 activity may be involved in the distinct astroglial response to SE, it is noteworthy to explore the roles of protein kinases in PARP1-mediated reactive astrogliosis and astroglial apoptosis following SE, albeit at a lesser extent. In the present study, inhibitions of protein kinase C (PKC), AKT and extracellular signal-related kinases 1/2 (ERK1/2), but not calcium/calmodulin-dependent protein kinase II (CaMKII), attenuated CA1 reactive astrogliosis accompanied by reducing PARP1 activity following SE, respectively. However, inhibition of AKT and ERK1/2 deteriorated SE-induced dentate astroglial loss concomitant with the diminished PARP1 activity. Following SE, PKC- and AKT inhibitors diminished phosphoprotein enriched in astrocytes of 15 kDa (PEA15)-S104 and -S116 phosphorylations in CA1 astrocytes, but not in dentate astrocytes, respectively. Inhibitors of PKC, AKT and ERK1/2 also abrogated SE-induced nuclear factor-κB (NF-κB)-S311 and -S468 phosphorylations in CA1 astrocytes. In contrast, both AKT and ERK1/2 inhibitors enhanced NF-κB-S468 phosphorylation in dentate astrocytes. Furthermore, PARP1 inhibitor aggravated dentate astroglial loss following SE. AKT inhibition deteriorated dentate astroglial loss and led to CA1 astroglial apoptosis following SE, which were ameliorated by AKT activation. These findings suggest that activities of PARP1, PEA15 and NF-κB may be distinctly regulated by PKC, AKT and ERK1/2, which may be involved in regional specific astroglial responses following SE.
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Affiliation(s)
- Ji-Eun Kim
- Department of Anatomy and Neurobiology, Institute of Epilepsy Research, College of Medicine, Hallym University, Chuncheon, South Korea
| | - Tae-Cheon Kang
- Department of Anatomy and Neurobiology, Institute of Epilepsy Research, College of Medicine, Hallym University, Chuncheon, South Korea
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128
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Wenzel TJ, Bajwa E, Klegeris A. Cytochrome c can be released into extracellular space and modulate functions of human astrocytes in a toll-like receptor 4-dependent manner. Biochim Biophys Acta Gen Subj 2019; 1863:129400. [PMID: 31344401 DOI: 10.1016/j.bbagen.2019.07.009] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Revised: 06/23/2019] [Accepted: 07/18/2019] [Indexed: 11/16/2022]
Abstract
BACKGROUND Chronic activation of glial cells contributes to neurodegenerative diseases. Cytochrome c (CytC) is a soluble mitochondrial protein that can act as a damage-associated molecular pattern (DAMP) when released into the extracellular space from damaged cells. CytC causes immune activation of microglia in a toll-like receptor (TLR) 4-dependent manner. The effects of extracellular CytC on astrocytes are unknown. Astrocytes, which are the most abundant glial cell type in the brain, express TLR 4 and secrete inflammatory mediators; therefore, we hypothesized that extracellular CytC can interact with the TLR 4 of astrocytes inducing their release of inflammatory molecules and cytotoxins. METHOD Experiments were conducted using primary human astrocytes, U118 MG human astrocytic cells, BV-2 murine microglia, and SH-SY5Y human neuronal cells. RESULTS Extracellularly applied CytC increased the secretion of interleukin (IL)-1β, granulocyte-macrophage colony stimulating factor (GM-CSF) and IL-12 p70 by cultured primary human astrocytes. Anti-TLR 4 antibodies blocked the CytC-induced secretion of IL-1β and GM-CSF by astrocytes. Supernatants from CytC-activated astrocytes were toxic to human SH-SY5Y neuronal cells. We also demonstrated CytC release from damaged glial cells by measuring CytC in the supernatants of BV-2 microglia after their exposure to cytotoxic concentrations of staurosporine, amyloid-β peptides (Aβ42) and tumor necrosis factor-α. CONCLUSION CytC can be released into the extracellular space from damaged glial cells causing immune activation of astrocytes in a TLR 4-dependent manner. GENERAL SIGNIFICANCE Astrocyte activation by CytC may contribute to neuroinflammation and neuronal death in neurodegenerative diseases. Astrocyte TLR 4 could be a potential therapeutic target in these diseases.
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Affiliation(s)
- Tyler J Wenzel
- Department of Biology, University of British Columbia Okanagan Campus, Kelowna, British Columbia V1V 1V7, Canada
| | - Ekta Bajwa
- Department of Biology, University of British Columbia Okanagan Campus, Kelowna, British Columbia V1V 1V7, Canada
| | - Andis Klegeris
- Department of Biology, University of British Columbia Okanagan Campus, Kelowna, British Columbia V1V 1V7, Canada.
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129
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Savchenko E, Teku GN, Boza-Serrano A, Russ K, Berns M, Deierborg T, Lamas NJ, Wichterle H, Rothstein J, Henderson CE, Vihinen M, Roybon L. FGF family members differentially regulate maturation and proliferation of stem cell-derived astrocytes. Sci Rep 2019; 9:9610. [PMID: 31270389 PMCID: PMC6610107 DOI: 10.1038/s41598-019-46110-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Accepted: 06/23/2019] [Indexed: 12/20/2022] Open
Abstract
The glutamate transporter 1 (GLT1) is upregulated during astrocyte development and maturation in vivo and is vital for astrocyte function. Yet it is expressed at low levels by most cultured astrocytes. We previously showed that maturation of human and mouse stem cell-derived astrocytes – including functional glutamate uptake – could be enhanced by fibroblast growth factor (FGF)1 or FGF2. Here, we examined the specificity and mechanism of action of FGF2 and other FGF family members, as well as neurotrophic and differentiation factors, on mouse embryonic stem cell-derived astrocytes. We found that some FGFs – including FGF2, strongly increased GLT1 expression and enhanced astrocyte proliferation, while others (FGF16 and FGF18) mainly affected maturation. Interestingly, BMP4 increased astrocytic GFAP expression, and BMP4-treated astrocytes failed to promote the survival of motor neurons in vitro. Whole transcriptome analysis showed that FGF2 treatment regulated multiple genes linked to cell division, and that the mRNA encoding GLT1 was one of the most strongly upregulated of all astrocyte canonical markers. Since GLT1 is expressed at reduced levels in many neurodegenerative diseases, activation of this pathway is of potential therapeutic interest. Furthermore, treatment with FGFs provides a robust means for expansion of functionally mature stem cell-derived astrocytes for preclinical investigation.
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Affiliation(s)
- Ekaterina Savchenko
- Department of Experimental Medical Science, BMC D10, Faculty of Medicine, Lund University, SE-22184, Lund, Sweden.,MultiPark and Lund Stem Cell Center, Faculty of Medicine, Lund University, SE-22184, Lund, Sweden
| | - Gabriel N Teku
- Department of Experimental Medical Science, Faculty of Medicine, BMC B13, Lund University, SE-22184, Lund, Sweden
| | - Antonio Boza-Serrano
- Department of Experimental Medical Science, Faculty of Medicine, BMC B11, Lund University, SE-22184, Lund, Sweden
| | - Kaspar Russ
- Department of Experimental Medical Science, BMC D10, Faculty of Medicine, Lund University, SE-22184, Lund, Sweden.,MultiPark and Lund Stem Cell Center, Faculty of Medicine, Lund University, SE-22184, Lund, Sweden
| | - Manon Berns
- Department of Experimental Medical Science, BMC D10, Faculty of Medicine, Lund University, SE-22184, Lund, Sweden.,MultiPark and Lund Stem Cell Center, Faculty of Medicine, Lund University, SE-22184, Lund, Sweden
| | - Tomas Deierborg
- Department of Experimental Medical Science, Faculty of Medicine, BMC B11, Lund University, SE-22184, Lund, Sweden
| | - Nuno J Lamas
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal, and ICVS/3B's, PT Government Associate Laboratory, Braga/Guimarães, Portugal.,Anatomic Pathology Service, Pathology Department, Hospital and University Center of Porto, Largo Professor Abel Salazar, 4099-001, Porto, Portugal
| | - Hynek Wichterle
- Center for Motor Neuron Biology and Disease, Columbia Stem Cell Initiative, Columbia Translational Neuroscience Initiative, Columbia University, New York, NY, 10032, USA.,Department of Pathology and Cell Biology, Neurology, and Neuroscience, College of Physicians and Surgeons, Columbia University, New York, NY, 10032, USA.,Project A.L.S./Jenifer Estess Laboratory for Stem Cell Research, New York, NY, 10032, USA
| | - Jeffrey Rothstein
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.,Brain Science Institute, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.,Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.,Program in Cellular and Molecular Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Christopher E Henderson
- Center for Motor Neuron Biology and Disease, Columbia Stem Cell Initiative, Columbia Translational Neuroscience Initiative, Columbia University, New York, NY, 10032, USA.,Department of Pathology and Cell Biology, Neurology, and Neuroscience, College of Physicians and Surgeons, Columbia University, New York, NY, 10032, USA.,Project A.L.S./Jenifer Estess Laboratory for Stem Cell Research, New York, NY, 10032, USA.,Department of Rehabilitation and Regenerative Medicine, College of Physicians and Surgeons, Columbia University, New York, NY, 10032, USA.,Target ALS Foundation, New York, NY, 10032, USA.,Biogen Inc., Cambridge, MA, 02142, USA
| | - Mauno Vihinen
- Department of Experimental Medical Science, Faculty of Medicine, BMC B13, Lund University, SE-22184, Lund, Sweden
| | - Laurent Roybon
- Department of Experimental Medical Science, BMC D10, Faculty of Medicine, Lund University, SE-22184, Lund, Sweden. .,MultiPark and Lund Stem Cell Center, Faculty of Medicine, Lund University, SE-22184, Lund, Sweden.
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130
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Braga DV, Wanderley Picanço-Diniz DL, Herculano Matos Oliveira KR, Luz WL, Soares de Moraes SA, Fonseca Passos AC, de Jesus Oliveira Batista E, Grisólia A, Herculano AM. Adenosine A1 receptors modulate the Na+-Hypertonicity induced glutamate release in hypothalamic glial cells. Neurochem Int 2019; 126:64-68. [DOI: 10.1016/j.neuint.2019.02.013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Revised: 02/11/2019] [Accepted: 02/18/2019] [Indexed: 02/09/2023]
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131
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Lu L, Armstrong EA, Yager JY, Unsworth LD. Sustained Release of Dexamethasone from Sulfobutyl Ether β-cyclodextrin Modified Self-Assembling Peptide Nanoscaffolds in a Perinatal Rat Model of Hypoxia-Ischemia. Adv Healthc Mater 2019; 8:e1900083. [PMID: 30977596 DOI: 10.1002/adhm.201900083] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Revised: 03/13/2019] [Indexed: 11/10/2022]
Abstract
Inflammation plays a critical role in the development of hypoxia-ischemia (HI) induced newborn brain damage. A localized, sustained delivery of dexamethasone (Dex) through an intracerebral injection could reduce the inflammatory response in the injured perinatal brain while avoiding unnecessary side effects. Herein, investigated using anionic sulfobutyl ether β-cyclodextrin (SBE-β-CD) to load Dex in the (RADA)4 nanofiber networks as a means of reducing the inflammatory response to HI injury is investigated. The ionic interaction between SBE-β-CD and (RADA)4 dramatically affects nanofiber formation and the stability of the nanoscaffold is highly dependent on the SBE-β-CD/(RADA)4 ratio. It is observed that the Dex release rate is affected by the concentration of SBE-β-CD and (RADA)4 peptide. A higher concentration of SBE-β-CD or (RADA)4 results in a higher drug encapsulation efficiency and slower release rate of Dex. This phenomenon may be related to the structure of fiber bundles. Animal studies show that nanoscaffold loaded with Dex inhibits both microglia activation and glial scar formation compared to controls (Dex alone or nanoscaffold alone) within 2 days of injury. It is thought that this is a step toward building a multifaceted nanoscaffold that can be used to treat HI events in perinates.
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Affiliation(s)
- Lei Lu
- School of Life Science and EngineeringSouthwest Jiaotong University Chengdu Sichuan 611756 China
- Department of Chemical and Materials EngineeringUniversity of Alberta Edmonton Alberta T6G 2V4 Canada
| | - Edward A. Armstrong
- Department of PediatricsDivision of Pediatric NeurosciencesUniversity of Alberta Edmonton Alberta T6G 1C9 Canada
| | - Jerome Y. Yager
- Department of PediatricsDivision of Pediatric NeurosciencesUniversity of Alberta Edmonton Alberta T6G 1C9 Canada
| | - Larry D. Unsworth
- Department of Chemical and Materials EngineeringUniversity of Alberta Edmonton Alberta T6G 2V4 Canada
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132
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Lauranzano E, Campo E, Rasile M, Molteni R, Pizzocri M, Passoni L, Bello L, Pozzi D, Pardi R, Matteoli M, Ruiz-Moreno A. A Microfluidic Human Model of Blood-Brain Barrier Employing Primary Human Astrocytes. ACTA ACUST UNITED AC 2019; 3:e1800335. [PMID: 32648668 DOI: 10.1002/adbi.201800335] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2018] [Revised: 03/20/2019] [Indexed: 12/19/2022]
Abstract
The neurovascular unit (NVU) is the most important biological barrier between vascular districts and central nervous system (CNS) parenchyma, which maintains brain homeostasis, protects the CNS from pathogens penetration, and mediates neuroimmune communication. T lymphocytes migration across the blood-brain barrier is heavily affected in different brain diseases, representing a major target for novel drug development. In vitro models of NVU could represent a primary tool to investigate the molecular events occurring at this interface. To move toward the establishment of personalized therapies, a patient-related NVU-model is set, incorporating human primary astrocytes integrated into a microfluidic platform. The model is morphologically and functionally characterized, proving to be an advantageous tool to investigate human T lymphocytes transmigration and thus the efficacy of potential novel drugs affecting this process.
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Affiliation(s)
- Eliana Lauranzano
- Humanitas Clinical and Research Center-IRCCS, via Manzoni 56, 20089, Rozzano, MI, Italy
| | - Elena Campo
- Humanitas Clinical and Research Center-IRCCS, via Manzoni 56, 20089, Rozzano, MI, Italy
| | - Marco Rasile
- Humanitas Clinical and Research Center-IRCCS, via Manzoni 56, 20089, Rozzano, MI, Italy.,Department of Biomedical Science, Laboratory of Pharmacology and Brain Pathology, Humanitas University, Via Rita Levi Montalcini 4, 20090, Pieve Emanuele, MI, Italy
| | - Raffaella Molteni
- Division of Immunology, Transplantation and Infectious Diseases, Leukocyte Biology Unit, San Raffaele Scientific Institute, Via Olgettina 58, 20132, Milan, Italy
| | - Marco Pizzocri
- Humanitas Clinical and Research Center-IRCCS, via Manzoni 56, 20089, Rozzano, MI, Italy
| | - Lorena Passoni
- Humanitas Clinical and Research Center-IRCCS, via Manzoni 56, 20089, Rozzano, MI, Italy
| | - Lorenzo Bello
- Humanitas Clinical and Research Center-IRCCS, via Manzoni 56, 20089, Rozzano, MI, Italy.,Department of Oncology and Hematology, University of Milan, Via Festa del Perdono 7, 20122, Milan, Italy
| | - Davide Pozzi
- Humanitas Clinical and Research Center-IRCCS, via Manzoni 56, 20089, Rozzano, MI, Italy.,Department of Biomedical Science, Laboratory of Pharmacology and Brain Pathology, Humanitas University, Via Rita Levi Montalcini 4, 20090, Pieve Emanuele, MI, Italy
| | - Ruggero Pardi
- Division of Immunology, Transplantation and Infectious Diseases, Leukocyte Biology Unit, San Raffaele Scientific Institute, Via Olgettina 58, 20132, Milan, Italy.,School of Medicine, Vita-Salute San Raffaele University, Via Olgettina 58, 20132, Milan, Italy
| | - Michela Matteoli
- Humanitas Clinical and Research Center-IRCCS, via Manzoni 56, 20089, Rozzano, MI, Italy.,Department of Biomedical Science, Laboratory of Pharmacology and Brain Pathology, Humanitas University, Via Rita Levi Montalcini 4, 20090, Pieve Emanuele, MI, Italy
| | - Ana Ruiz-Moreno
- Humanitas Clinical and Research Center-IRCCS, via Manzoni 56, 20089, Rozzano, MI, Italy
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133
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The contribution of astrocytes to the neuroinflammatory response in multiple sclerosis and experimental autoimmune encephalomyelitis. Acta Neuropathol 2019; 137:757-783. [PMID: 30847559 DOI: 10.1007/s00401-019-01980-7] [Citation(s) in RCA: 156] [Impact Index Per Article: 31.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Revised: 02/21/2019] [Accepted: 02/23/2019] [Indexed: 02/06/2023]
Abstract
Neuroinflammation is the coordinated response of the central nervous system (CNS) to threats to its integrity posed by a variety of conditions, including autoimmunity, pathogens and trauma. Activated astrocytes, in concert with other cellular elements of the CNS and immune system, are important players in the modulation of the neuroinflammatory response. During neurological disease, they produce and respond to cellular signals that often lead to dichotomous processes, which can promote further damage or contribute to repair. This occurs also in multiple sclerosis (MS), where astrocytes are now recognized as key components of its immunopathology. Evidence supporting this role has emerged not only from studies in MS patients, but also from animal models, among which the experimental autoimmune encephalomyelitis (EAE) model has proved especially instrumental. Based on this premise, the purpose of the present review is to summarize the current knowledge of astrocyte behavior in MS and EAE. Following a brief description of the pathological characteristics of the two diseases and the main functional roles of astrocytes in CNS physiology, we will delve into the specific responses of this cell population, analyzing MS and EAE in parallel. We will define the temporal and anatomical profile of astroglial activation, then focus on key processes they participate in. These include: (1) production and response to soluble mediators (e.g., cytokines and chemokines), (2) regulation of oxidative stress, and (3) maintenance of BBB integrity and function. Finally, we will review the state of the art on the available methods to measure astroglial activation in vivo in MS patients, and how this could be exploited to optimize diagnosis, prognosis and treatment decisions. Ultimately, we believe that integrating the knowledge obtained from studies in MS and EAE may help not only better understand the pathophysiology of MS, but also uncover new signals to be targeted for therapeutic intervention.
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134
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Souza DG, Almeida RF, Souza DO, Zimmer ER. The astrocyte biochemistry. Semin Cell Dev Biol 2019; 95:142-150. [PMID: 30951895 DOI: 10.1016/j.semcdb.2019.04.002] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2018] [Revised: 03/19/2019] [Accepted: 04/01/2019] [Indexed: 02/06/2023]
Abstract
Astrocytes are a unique and dynamic subtype of glial cells in the central nervous system (CNS). Understanding their biochemical reactions and their influence in the surrounding cells is extremely important in the neuroscience field. They exert important influence in the neurotransmission, ionic homeostasis and also release neuroactive molecules termed gliotransmitters. Additionally, they metabolize, store and release metabolic substrates to meet high brain energy requirements. In this review, we highlight the main biochemical reactions regarding energy metabolism that take place in astrocytes. Special attention is given to synthesis, storage and catabolism of glucose, release of lactate, oxidation of fatty acids, production of ketone bodies, and metabolism of the main neurotransmitters, glutamate and GABA. The recent findings allow proposing these cells as key players controlling the energetic homeostasis in the CNS.
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Affiliation(s)
- Débora G Souza
- Graduate Program in Biological Sciences: Biochemistry, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil
| | - Roberto F Almeida
- Graduate Program in Biological Sciences: Biochemistry, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil; Exact and Biological Sciences Institute, Biological Sciences Department, Federal University of Ouro Preto, Ouro Preto, Brazil
| | - Diogo O Souza
- Graduate Program in Biological Sciences: Biochemistry, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil; Department of Biochemistry, UFRGS, Porto Alegre, Brazil
| | - Eduardo R Zimmer
- Graduate Program in Biological Sciences: Biochemistry, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil; Department of Pharmacology, UFRGS, Porto Alegre, Brazil; Graduate Program in Biological Sciences: Pharmacology and Therapeutics, UFRGS, Porto Alegre, Brazil; Brain Institute of Rio Grande do Sul (BraIns), Pontifical Catholic University of Rio Grande do Sul, Porto Alegre, Brazil.
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135
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Woo J, Han YE, Koh W, Won J, Park MG, An H, Lee CJ. Pharmacological Dissection of Intrinsic Optical Signal Reveals a Functional Coupling between Synaptic Activity and Astrocytic Volume Transient. Exp Neurobiol 2019; 28:30-42. [PMID: 30853822 PMCID: PMC6401548 DOI: 10.5607/en.2019.28.1.30] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2019] [Revised: 02/12/2019] [Accepted: 02/14/2019] [Indexed: 11/19/2022] Open
Abstract
The neuronal activity-dependent change in the manner in which light is absorbed or scattered in brain tissue is called the intrinsic optical signal (IOS), and provides label-free, minimally invasive, and high spatial (~100 µm) resolution imaging for visualizing neuronal activity patterns. IOS imaging in isolated brain slices measured at an infrared wavelength (>700 nm) has recently been attributed to the changes in light scattering and transmittance due to aquaporin-4 (AQP4)-dependent astrocytic swelling. The complexity of functional interactions between neurons and astrocytes, however, has prevented the elucidation of the series of molecular mechanisms leading to the generation of IOS. Here, we pharmacologically dissected the IOS in the acutely prepared brain slices of the stratum radiatum of the hippocampus, induced by 1 s/20 Hz electrical stimulation of Schaffer-collateral pathway with simultaneous measurement of the activity of the neuronal population by field potential recordings. We found that 55% of IOSs peak upon stimulation and originate from postsynaptic AMPA and NMDA receptors. The remaining originated from presynaptic action potentials and vesicle fusion. Mechanistically, the elevated extracellular glutamate and K+ during synaptic transmission were taken up by astrocytes via a glutamate transporter and quinine-sensitive K2P channel, followed by an influx of water via AQP-4. We also found that the decay of IOS is mediated by the DCPIB- and NPPB-sensitive anion channels in astrocytes. Altogether, our results demonstrate that the functional coupling between synaptic activity and astrocytic transient volume change during excitatory synaptic transmission is the major source of IOS.
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Affiliation(s)
- Junsung Woo
- Center for Glia-Neuron Interaction, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea
| | - Young-Eun Han
- Center for Glia-Neuron Interaction, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea.,Department of Neuroscience, Division of Bio-medical Science & Technology, KIST School, Korea University of Science and Technology, Seoul 02792, Korea.,Center for Cognition and Sociality, Institute for Basic Science (IBS), Daejeon 34126, Korea
| | - Wuhyun Koh
- Center for Glia-Neuron Interaction, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea.,Department of Neuroscience, Division of Bio-medical Science & Technology, KIST School, Korea University of Science and Technology, Seoul 02792, Korea.,Center for Cognition and Sociality, Institute for Basic Science (IBS), Daejeon 34126, Korea
| | - Joungha Won
- Center for Glia-Neuron Interaction, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea.,Center for Cognition and Sociality, Institute for Basic Science (IBS), Daejeon 34126, Korea.,Department of Biological Sciences, Korea Advanced Institutes of Science and Technology (KAIST), Daejeon 34141, Korea
| | - Min Gu Park
- Center for Glia-Neuron Interaction, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea.,Center for Cognition and Sociality, Institute for Basic Science (IBS), Daejeon 34126, Korea.,KU-KIST, Graduate School of Converging Science and Technology, Korea University, Seoul 02841, Korea
| | - Heeyoung An
- Center for Glia-Neuron Interaction, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea.,Center for Cognition and Sociality, Institute for Basic Science (IBS), Daejeon 34126, Korea.,KU-KIST, Graduate School of Converging Science and Technology, Korea University, Seoul 02841, Korea
| | - C Justin Lee
- Center for Glia-Neuron Interaction, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea.,Department of Neuroscience, Division of Bio-medical Science & Technology, KIST School, Korea University of Science and Technology, Seoul 02792, Korea.,Center for Cognition and Sociality, Institute for Basic Science (IBS), Daejeon 34126, Korea
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136
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Moura RP, Martins C, Pinto S, Sousa F, Sarmento B. Blood-brain barrier receptors and transporters: an insight on their function and how to exploit them through nanotechnology. Expert Opin Drug Deliv 2019; 16:271-285. [PMID: 30767695 DOI: 10.1080/17425247.2019.1583205] [Citation(s) in RCA: 66] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
INTRODUCTION The blood-brain barrier (BBB) is a highly limiting barrier that prevents the brain from contacting with several circulating molecules, including harmful agents. However, certain systemic nutrients and macromolecules are able to cross the BBB and reach the brain parenchyma, involving the interaction with multiple receptors and/or transporters at the BBB surface. Nanotechnology allows the creation of drug vehicles, functionalized with targeting ligands for binding specific BBB receptors and/or transporters, hence triggering the transport through this biobarrier. AREAS COVERED This review focuses the BBB receptors/transporters to be exploited in regard to their overall structure and biologic function, as well as their role in the development of strategies envisaging drug delivery to the brain. Then, the interplay between the targeting of these BBB receptors/transporters and nanotechnology is explored, as they can increase by several-fold the effectiveness of brain-targeted therapies. EXPERT OPINION Nanomedicine may be particularly useful in brain drug delivery, mainly due to the possibility of functionalizing nanoparticles to target specific receptors/transporters. Since the BBB is endowed with numerous receptors and transporters responsible for regulating the proper metabolic activity of the brain, their targeting can be a promising bypass strategy to circumvent the hurdle that the BBB represents for brain drug delivery.
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Affiliation(s)
- Rui Pedro Moura
- a CESPU - Instituto de Investigação e Formação Avançada em Ciências e Tecnologias da Saúde , Gandra , Portugal
| | - Cláudia Martins
- b I3S - Instituto de Investigação e Inovação em Saúde , Universidade do Porto , Porto , Portugal.,c INEB - Instituto de Engenharia Biomédica , Universidade do Porto , Porto , Portugal.,d ICBAS - Instituto de Ciências Biomédicas Abel Salazar , Universidade do Porto , Porto , Portugal
| | - Soraia Pinto
- b I3S - Instituto de Investigação e Inovação em Saúde , Universidade do Porto , Porto , Portugal.,c INEB - Instituto de Engenharia Biomédica , Universidade do Porto , Porto , Portugal
| | - Flávia Sousa
- a CESPU - Instituto de Investigação e Formação Avançada em Ciências e Tecnologias da Saúde , Gandra , Portugal.,b I3S - Instituto de Investigação e Inovação em Saúde , Universidade do Porto , Porto , Portugal.,c INEB - Instituto de Engenharia Biomédica , Universidade do Porto , Porto , Portugal.,d ICBAS - Instituto de Ciências Biomédicas Abel Salazar , Universidade do Porto , Porto , Portugal
| | - Bruno Sarmento
- a CESPU - Instituto de Investigação e Formação Avançada em Ciências e Tecnologias da Saúde , Gandra , Portugal.,b I3S - Instituto de Investigação e Inovação em Saúde , Universidade do Porto , Porto , Portugal.,c INEB - Instituto de Engenharia Biomédica , Universidade do Porto , Porto , Portugal
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137
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Down-Regulation of Astrocytic Kir4.1 Channels during the Audiogenic Epileptogenesis in Leucine-Rich Glioma-Inactivated 1 ( Lgi1) Mutant Rats. Int J Mol Sci 2019; 20:ijms20051013. [PMID: 30813600 PMCID: PMC6429235 DOI: 10.3390/ijms20051013] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Revised: 02/14/2019] [Accepted: 02/21/2019] [Indexed: 02/07/2023] Open
Abstract
The dysfunction of astrocytic inwardly rectifying potassium (Kir) 4.1 channels, which mediate the spatial potassium-buffering function of astrocytes, is known to be involved in the development of epilepsy. Here, we analyzed the Kir4.1 expressional changes in Leucine-Rich Glioma-Inactivated 1 (Lgi1) mutant rats, which is a model of autosomal dominant lateral temporal lobe epilepsy in humans, to clarify the role of astrocytic Kir4.1 channels in Lgi1-related epileptogenesis. Priming acoustic stimulation (at postnatal day 16) conferred seizure susceptibility on Lgi1 mutant rats, which evoked audiogenic seizures with test stimulation at eight weeks. In the seizure-susceptible Lgi1 mutant rats (before test stimulation), astrocytic Kir4.1 expression was down-regulated region-specifically in the cerebral cortex, hippocampus, and amygdala. In addition, prophylactic treatments of Lgi1 mutant rats with valproic acid (VPA, 30 mg/kg and 200 mg/kg) for two weeks prevented both the development of seizure susceptibility and the down-regulation of Kir4.1 expression in astrocytes. The present study demonstrated for the first time that the astrocytic Kir4.1 expression was reduced in the Lgi1-related seizure model, suggesting that the down-regulation of Kir4.1 channels in astrocytes is involved in audiogenic epileptogenesis caused by Lgi1 mutation. In addition, VPA seemed to have a prophylactic effect on Lgi1-related seizures.
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138
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Lee BJ, Jun HO, Kim JH, Kim JH. Astrocytic cystine/glutamate antiporter is a key regulator of erythropoietin expression in the ischemic retina. FASEB J 2019; 33:6045-6054. [PMID: 30742774 DOI: 10.1096/fj.201802144r] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Ischemic retinopathies and optic neuropathies are important causes of vision loss. The neuroprotective effect of erythropoietin (EPO) in ischemic neuronal injury and the expression of EPO and its receptor in retinal tissue have been well documented. However, the exact regulatory mechanism of EPO expression in retinal ischemia still remains to be elucidated. In this study, we investigated the role of cystine/glutamate antiporter (system xc-) in the regulation of astrocytic EPO expression by using both in vitro and in vivo models. Under hypoxia, the expression of astrocytic system xc- is up-regulated both in vitro and in vivo. Inhibition of system xc- resulted in depletion of intracellular glutathione (GSH) and decrement of GSH disulfide ratios in human brain astrocytes (HBAs). In HBAs, hypoxia-induced stabilization of hypoxia-inducible factor (Hif)-2α is nearly completely abolished by inhibition of system xc-. Hypoxia-induced up-regulation of astrocytic EPO expression is suppressed by both pharmacological inhibition and siRNA-mediated knockdown of system xc-. In contrast, basal EPO expression under normoxia is not affected by system xc- modulation. In summary, under hypoxia, increased system xc- acts as the major source of intracellular GSH, which helps in stabilizing Hif-2α and subsequent up-regulation of EPO in astrocytes.-Lee, B. J., Jun, H. O., Kim, J. H., Kim, J. H. Astrocytic cystine/glutamate antiporter is a key regulator of erythropoietin expression in the ischemic retina.
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Affiliation(s)
- Byung Joo Lee
- Fight Against Angiogenesis-Related Blindness (FARB) Laboratory, Clinical Research Institute, Seoul National University Hospital, Seoul National University, Seoul, South Korea.,Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul National University, Seoul, South Korea
| | - Hyoung Oh Jun
- Fight Against Angiogenesis-Related Blindness (FARB) Laboratory, Clinical Research Institute, Seoul National University Hospital, Seoul National University, Seoul, South Korea
| | - Jin Hyoung Kim
- Fight Against Angiogenesis-Related Blindness (FARB) Laboratory, Clinical Research Institute, Seoul National University Hospital, Seoul National University, Seoul, South Korea
| | - Jeong Hun Kim
- Fight Against Angiogenesis-Related Blindness (FARB) Laboratory, Clinical Research Institute, Seoul National University Hospital, Seoul National University, Seoul, South Korea.,Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul National University, Seoul, South Korea.,Department of Ophthalmology, Seoul National University College of Medicine, Seoul National University, Seoul, South Korea
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139
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Tan Q, Li Y, Guo P, Zhou J, Jiang Z, Liu X, Chen Z, Feng H. Tolvaptan attenuated brain edema in experimental intracerebral hemorrhage. Brain Res 2019; 1715:41-46. [PMID: 30703371 DOI: 10.1016/j.brainres.2019.01.033] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Revised: 01/05/2019] [Accepted: 01/26/2019] [Indexed: 12/25/2022]
Abstract
Arginine-vasopressin (AVP) is believed to be positively correlated with the brain edema formation, but the underlying mechanism is still unclear. In this study, we explored the role of the V2 receptors antagonist tolvaptan on brain edema following intracerebral hemorrhage (ICH) with a rat model. Animals were randomly given tolvaptan or vehicle through oral gavage at 12 h, 36 h, and 60 h after ICH surgery. Brain swelling (%), brain water content(BWC), neurological scores, Evans blue fluorescence and blood-brain barrier (BBB) tight junction proteins were measured to evaluate the effect of tolvaptan in ICH. We found that tolvaptan alleviated the brain swelling (%), decreased the BWC growth, and attenuated the neurological deficits after ICH (p < 0.05, vs vehicle). What's more, tolvaptan increased the expression of ZO-1 and occludin (p < 0.05, vs vehicle), which might be attributed to the down-regulated effects of tolvaptan on MMP-9. These results provided evidence supporting the use of tolvaptan for ICH-induced brain edema. Large animal experiments are required to further explore the efficacy and mechanism of tolvaptan in ICH treatment.
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Affiliation(s)
- Qiang Tan
- Department of Neurosurgery, Southwest Hospital, Third Military Medical University, Army Medical University, Chongqing 400038, China
| | - Yuhan Li
- State Key Laboratory Of Silkworm Genome Biology, Southwest University, No. 2 Rd Tiansheng, Beibei District of Chongqing, 400715, China
| | - Peiwen Guo
- Department of Neurosurgery, Southwest Hospital, Third Military Medical University, Army Medical University, Chongqing 400038, China
| | - Jiru Zhou
- Department of Neurosurgery, Southwest Hospital, Third Military Medical University, Army Medical University, Chongqing 400038, China
| | - Zhouyang Jiang
- Department of Neurosurgery, Southwest Hospital, Third Military Medical University, Army Medical University, Chongqing 400038, China
| | - Xin Liu
- Department of Neurosurgery, Southwest Hospital, Third Military Medical University, Army Medical University, Chongqing 400038, China
| | - Zhi Chen
- Department of Neurosurgery, Southwest Hospital, Third Military Medical University, Army Medical University, Chongqing 400038, China
| | - Hua Feng
- Department of Neurosurgery, Southwest Hospital, Third Military Medical University, Army Medical University, Chongqing 400038, China.
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140
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Shih EK, Robinson MB. Role of Astrocytic Mitochondria in Limiting Ischemic Brain Injury? Physiology (Bethesda) 2019; 33:99-112. [PMID: 29412059 DOI: 10.1152/physiol.00038.2017] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Until recently, astrocyte processes were thought to be too small to contain mitochondria. However, it is now clear that mitochondria are found throughout fine astrocyte processes and are mobile with neuronal activity resulting in positioning near synapses. In this review, we discuss evidence that astrocytic mitochondria confer selective resiliency to astrocytes during ischemic insults and the functional significance of these mitochondria for normal brain function.
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Affiliation(s)
- Evelyn K Shih
- Children's Hospital of Philadelphia Research Institute , Philadelphia, Pennsylvania.,Children's Hospital of Philadelphia, Division of Neurology , Philadelphia, Pennsylvania.,Department of Pediatrics, University of Pennsylvania , Philadelphia, Pennsylvania
| | - Michael B Robinson
- Children's Hospital of Philadelphia Research Institute , Philadelphia, Pennsylvania.,Department of Pediatrics, University of Pennsylvania , Philadelphia, Pennsylvania.,Department of Systems Pharmacology and Translational Therapeutics, University of Pennsylvania , Philadelphia, Pennsylvania
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141
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Sepp K, Molnár Z, László AM, Alapi T, Tóth L, Serester A, Valkusz Z, Gálfi M, Radács M. Study of the Potential Endocrine-Disrupting Effects of Phenylurea Compounds on Neurohypophysis Cells In Vitro. Int J Endocrinol 2019; 2019:1546131. [PMID: 30881451 PMCID: PMC6387713 DOI: 10.1155/2019/1546131] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Revised: 11/01/2018] [Accepted: 11/15/2018] [Indexed: 11/18/2022] Open
Abstract
Homeostatic disruptor agents, and endocrine disruptor compounds (EDC) specifically, can originate from agricultural and industrial chemicals. If they modify the adaptation of living organisms as direct (e.g., by altering hormone regulation, membrane functions) and/or indirect (e.g., cell transformation mechanisms) factors, they are classified as EDC. We aimed to examine the potential endocrine-disrupting effects of phenylurea herbicides (phenuron, monuron, and diuron) on the oxytocin (OT) and arginine-vasopressin (AVP) release of neurohypophysis cell cultures (NH). In our experiments, monoamine-activated receptor functions of neurohypophyseal cells were used as a model. In vitro NH were prepared by enzymatic (trypsin, collagenase) and mechanical dissociation. In the experimental protocol, the basal levels of OT and AVP were determined as controls. Later, monoamine (epinephrine, norepinephrine, serotonin, histamine, and dopamine) activation (10-6 M, 30 min) and the effects of phenylurea (10-6 M, 60 min) alone and in combination (monoamines 10-6 M, 30 min + phenylureas 10-6 M, 60 min) with monoamine were studied. OT and AVP hormone contents in the supernatant media were measured by radioimmunoassay. The monoamine-activated receptor functions of neurohypophyseal cells were modified by the applied doses of phenuron, monuron, and diuron. It is concluded that the applied phenylurea herbicides are endocrine disruptor agents, at least in vitro for neurohypophysis function.
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Affiliation(s)
- Krisztián Sepp
- First Department of Internal Medicine, Faculty of Medicine, University of Szeged, Szeged, Hungary
| | - Zsolt Molnár
- Institute of Applied Science, Department of Environmental Biology and Education, Gyula Juhász Faculty of Education, University of Szeged, Szeged, Hungary
| | - Anna M. László
- Department of Biometrics and Agricultural Informatics, Faculty of Horticultural Science, Szent István University, Budapest, Hungary
| | - Tünde Alapi
- Department of Inorganic and Analytical Chemistry, Faculty of Science and Informatics, University of Szeged, Szeged, Hungary
| | - László Tóth
- Institute of Applied Science, Department of Environmental Biology and Education, Gyula Juhász Faculty of Education, University of Szeged, Szeged, Hungary
| | - Andrea Serester
- Institute of Applied Science, Department of Environmental Biology and Education, Gyula Juhász Faculty of Education, University of Szeged, Szeged, Hungary
| | - Zsuzsanna Valkusz
- First Department of Internal Medicine, Faculty of Medicine, University of Szeged, Szeged, Hungary
| | - Márta Gálfi
- Institute of Applied Science, Department of Environmental Biology and Education, Gyula Juhász Faculty of Education, University of Szeged, Szeged, Hungary
| | - Marianna Radács
- Institute of Applied Science, Department of Environmental Biology and Education, Gyula Juhász Faculty of Education, University of Szeged, Szeged, Hungary
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142
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Immunohistochemical Evaluation of Aquaporin-4 and its Correlation with CD68, IBA-1, HIF-1α, GFAP, and CD15 Expressions in Fatal Traumatic Brain Injury. Int J Mol Sci 2018; 19:ijms19113544. [PMID: 30423808 PMCID: PMC6274714 DOI: 10.3390/ijms19113544] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Revised: 11/04/2018] [Accepted: 11/07/2018] [Indexed: 12/11/2022] Open
Abstract
Traumatic brain injury (TBI) is one of the leading causes of death and disability worldwide. Our understanding of its pathobiology has substantially increased. Following TBI, the following occur, edema formation, brain swelling, increased intracranial pressure, changes in cerebral blood flow, hypoxia, neuroinflammation, oxidative stress, excitotoxicity, and apoptosis. Experimental animal models have been developed. However, the difficulty in mimicking human TBI explains why few neuroprotective strategies, drawn up on the basis of experimental studies, have translated into improved therapeutic strategies for TBI patients. In this study, we retrospectively examined brain samples in 145 cases of death after different survival times following TBI, to investigate aquaporin-4 (AQP4) expression and correlation with hypoxia, and neuroinflammation in human TBI. Antibodies anti-glial fibrillary acid protein (GFAP), aquaporin-4 (AQP4), hypoxia induced factor-1α (HIF-1α), macrophage/phagocytic activation (CD68), ionized calcium-binding adapter molecule-1 (IBA-1), and neutrophils (CD15) were used. AQP4 showed a significant, progressive increase between the control group and groups 2 (one-day survival) and 3 (three-day survival). There were further increases in AQP4 immunopositivity in groups 4 (seven-day survival), 5 (14-dayssurvival), and 6 (30-day survival), suggesting an upregulation of AQP4 at 7 to 30 days compared to group 1. GFAP showed its highest expression in non-acute cases at the astrocytic level compared with the acute TBI group. Data emerging from the HIF-1α reaction showed a progressive, significant increase. Immunohistochemistry with IBA-1 revealed activated microglia starting three days after trauma and progressively increasing in the next 15 to 20 days after the initial trauma. CD68 expression demonstrated basal macrophage and phagocytic activation mostly around blood vessels. Starting from one to three days of survival after TBI, an increase in the number of CD68 cells was progressively observed; at 15 and 30 days of survival, CD68 showed the most abundant immunopositivity inside or around the areas of necrosis. These findings need to be developed further to gain insight into the mechanisms through which brain AQP4 is upregulated. This could be of the utmost clinicopathological importance.
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143
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Price BR, Wilcock DM, Weekman EM. Hyperhomocysteinemia as a Risk Factor for Vascular Contributions to Cognitive Impairment and Dementia. Front Aging Neurosci 2018; 10:350. [PMID: 30429785 PMCID: PMC6220027 DOI: 10.3389/fnagi.2018.00350] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Accepted: 10/16/2018] [Indexed: 12/19/2022] Open
Abstract
Behind only Alzheimer's disease, vascular contributions to cognitive impairment and dementia (VCID) is the second most common cause of dementia, affecting roughly 10-40% of dementia patients. While there is no cure for VCID, several risk factors for VCID, such as diabetes, hypertension, and stroke, have been identified. Elevated plasma levels of homocysteine, termed hyperhomocysteinemia (HHcy), are a major, yet underrecognized, risk factor for VCID. B vitamin deficiency, which is the most common cause of HHcy, is common in the elderly. With B vitamin supplementation being a relatively safe and inexpensive therapeutic, the treatment of HHcy-induced VCID would seem straightforward; however, preclinical and clinical data shows it is not. Clinical trials using B vitamin supplementation have shown conflicting results about the benefits of lowering homocysteine and issues have arisen over proper study design within the trials. Studies using cell culture and animal models have proposed several mechanisms for homocysteine-induced cognitive decline, providing other targets for therapeutics. For this review, we will focus on HHcy as a risk factor for VCID, specifically, the different mechanisms proposed for homocysteine-induced cognitive decline and the clinical trials aimed at lowering plasma homocysteine.
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Affiliation(s)
| | | | - Erica M. Weekman
- Department of Physiology, Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, United States
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144
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Ohno Y, Kinboshi M, Shimizu S. Inwardly Rectifying Potassium Channel Kir4.1 as a Novel Modulator of BDNF Expression in Astrocytes. Int J Mol Sci 2018; 19:ijms19113313. [PMID: 30356026 PMCID: PMC6274740 DOI: 10.3390/ijms19113313] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Revised: 10/19/2018] [Accepted: 10/22/2018] [Indexed: 12/02/2022] Open
Abstract
Brain-derived neurotrophic factor (BDNF) is a key molecule essential for neural plasticity and development, and is implicated in the pathophysiology of various central nervous system (CNS) disorders. It is now documented that BDNF is synthesized not only in neurons, but also in astrocytes which actively regulate neuronal activities by forming tripartite synapses. Inwardly rectifying potassium (Kir) channel subunit Kir4.1, which is specifically expressed in astrocytes, constructs Kir4.1 and Kir4.1/5.1 channels, and mediates the spatial potassium (K+) buffering action of astrocytes. Recent evidence illustrates that Kir4.1 channels play important roles in bringing about the actions of antidepressant drugs and modulating BDNF expression in astrocytes. Although the precise mechanisms remain to be clarified, it seems likely that inhibition (down-regulation or blockade) of astrocytic Kir4.1 channels attenuates K+ buffering, increases neuronal excitability by elevating extracellular K+ and glutamate, and facilitates BDNF expression. Conversely, activation (up-regulation or opening) of Kir4.1 channels reduces neuronal excitability by lowering extracellular K+ and glutamate, and attenuates BDNF expression. Particularly, the former pathophysiological alterations seem to be important in epileptogenesis and pain sensitization, and the latter in the pathogenesis of depressive disorders. In this article, we review the functions of Kir4.1 channels, with a focus on their regulation of spatial K+ buffering and BDNF expression in astrocytes, and discuss the role of the astrocytic Kir4.1-BDNF system in modulating CNS disorders.
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Affiliation(s)
- Yukihiro Ohno
- Department of Pharmacology, Osaka University of Pharmaceutical Sciences, 4-20-1 Nasahara, Takatsuki, Osaka 569-1094, Japan.
| | - Masato Kinboshi
- Department of Pharmacology, Osaka University of Pharmaceutical Sciences, 4-20-1 Nasahara, Takatsuki, Osaka 569-1094, Japan.
| | - Saki Shimizu
- Department of Pharmacology, Osaka University of Pharmaceutical Sciences, 4-20-1 Nasahara, Takatsuki, Osaka 569-1094, Japan.
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145
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Deemyad T, Lüthi J, Spruston N. Astrocytes integrate and drive action potential firing in inhibitory subnetworks. Nat Commun 2018; 9:4336. [PMID: 30337521 PMCID: PMC6194108 DOI: 10.1038/s41467-018-06338-3] [Citation(s) in RCA: 69] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Accepted: 08/27/2018] [Indexed: 12/29/2022] Open
Abstract
Many brain functions depend on the ability of neural networks to temporally integrate transient inputs to produce sustained discharges. This can occur through cell-autonomous mechanisms in individual neurons and through reverberating activity in recurrently connected neural networks. We report a third mechanism involving temporal integration of neural activity by a network of astrocytes. Previously, we showed that some types of interneurons can generate long-lasting trains of action potentials (barrage firing) following repeated depolarizing stimuli. Here we show that calcium signaling in an astrocytic network correlates with barrage firing; that active depolarization of astrocyte networks by chemical or optogenetic stimulation enhances; and that chelating internal calcium, inhibiting release from internal stores, or inhibiting GABA transporters or metabotropic glutamate receptors inhibits barrage firing. Thus, networks of astrocytes influence the spatiotemporal dynamics of neural networks by directly integrating neural activity and driving barrages of action potentials in some populations of inhibitory interneurons. Specific types of inhibitory neurons exhibit prolonged, high-frequency barrages of action potentials. Here, the authors show that astrocytes might mediate such barrage firing.
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Affiliation(s)
- Tara Deemyad
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, 20147, USA.,Department of Neurobiology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, 15213, USA
| | - Joel Lüthi
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, 20147, USA.,Institute of Molecular Life Sciences, University of Zürich, Zürich, 8057, Switzerland
| | - Nelson Spruston
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, 20147, USA.
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146
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Thuringer D, Chanteloup G, Winckler P, Garrido C. The vesicular transfer of CLIC1 from glioblastoma to microvascular endothelial cells requires TRPM7. Oncotarget 2018; 9:33302-33311. [PMID: 30279961 PMCID: PMC6161795 DOI: 10.18632/oncotarget.26048] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Accepted: 08/16/2018] [Indexed: 01/01/2023] Open
Abstract
Chloride intracellular channel 1 (CLIC1) is highly expressed and secreted by human glioblastoma cells and cell lines such as U87, initiating cell migration and tumor growth. Here, we examined whether CLIC1 could be transferred to human primary microvascular endothelial cells (HMEC). We previously reported that the oncogenic microRNA, miR-5096, increased the release of extracellular vesicles (EVs) by which it increased its own transfer from U87 to surrounding cells. Thus, we also examined its effect on the CLIC1 transfer. In homotypic cultures, miR-5096 did not increase the expression of CLIC1 in U87 nor in HMEC. However, the endothelial CLIC1 level increased after exposure to EVs released by U87, and even more by miR-5096-loaded U87. The EVs-transferred CLIC1 was active in HMEC, promoting endothelial sprouting in matrigel. Cell exposure to EVs induced cytosolic Ca2+ spikes which were dependent on the transient receptor potential melastatin member 7 (TRPM7). TRPM7 silencing prevented Ca2+ spikes and the subsequent CLIC1 delivery into HMEC. Our data suggest that the vesicular transfer of CLIC1 between cells requires TRMP7 expression in recipient endothelial cells. How the vesicular transfer of CLIC1 is modulated in cancer therapy is a future challenge.
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Affiliation(s)
- Dominique Thuringer
- INSERM U1231, Laboratory of Excellence Ligue Nationale contre le Cancer, 21000 Dijon, France.,Université de Bourgogne Franche Comté, 21000 Dijon, France
| | - Gaetan Chanteloup
- INSERM U1231, Laboratory of Excellence Ligue Nationale contre le Cancer, 21000 Dijon, France.,Université de Bourgogne Franche Comté, 21000 Dijon, France
| | - Pascale Winckler
- AgroSup Dijon, PAM UMR, DImaCell Imaging Facility, Université de Bourgogne Franche Comté, 21000 Dijon, France
| | - Carmen Garrido
- INSERM U1231, Laboratory of Excellence Ligue Nationale contre le Cancer, 21000 Dijon, France.,Université de Bourgogne Franche Comté, 21000 Dijon, France.,Centre Georges François Leclerc (CGFL), 21000 Dijon, France
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147
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Schiweck J, Eickholt BJ, Murk K. Important Shapeshifter: Mechanisms Allowing Astrocytes to Respond to the Changing Nervous System During Development, Injury and Disease. Front Cell Neurosci 2018; 12:261. [PMID: 30186118 PMCID: PMC6111612 DOI: 10.3389/fncel.2018.00261] [Citation(s) in RCA: 136] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Accepted: 07/31/2018] [Indexed: 12/30/2022] Open
Abstract
Astrocytes are the most prevalent glial cells in the brain. Historically considered as “merely supporting” neurons, recent research has shown that astrocytes actively participate in a large variety of central nervous system (CNS) functions including synaptogenesis, neuronal transmission and synaptic plasticity. During disease and injury, astrocytes efficiently protect neurons by various means, notably by sealing them off from neurotoxic factors and repairing the blood-brain barrier. Their ramified morphology allows them to perform diverse tasks by interacting with synapses, blood vessels and other glial cells. In this review article, we provide an overview of how astrocytes acquire their complex morphology during development. We then move from the developing to the mature brain, and review current research on perisynaptic astrocytic processes, with a particular focus on how astrocytes engage synapses and modulate their formation and activity. Comprehensive changes have been reported in astrocyte cell shape in many CNS pathologies. Factors influencing these morphological changes are summarized in the context of brain pathologies, such as traumatic injury and degenerative conditions. We provide insight into the molecular, cellular and cytoskeletal machinery behind these shape changes which drive the dynamic remodeling in astrocyte morphology during injury and the development of pathologies.
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Affiliation(s)
- Juliane Schiweck
- Institute for Biochemistry, Charité Universitätsmedizin Berlin, Berlin, Germany
| | - Britta J Eickholt
- Institute for Biochemistry, Charité Universitätsmedizin Berlin, Berlin, Germany
| | - Kai Murk
- Institute for Biochemistry, Charité Universitätsmedizin Berlin, Berlin, Germany
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148
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Medina-Rodriguez EM, Lowell JA, Worthen RJ, Syed SA, Beurel E. Involvement of Innate and Adaptive Immune Systems Alterations in the Pathophysiology and Treatment of Depression. Front Neurosci 2018; 12:547. [PMID: 30174579 PMCID: PMC6107705 DOI: 10.3389/fnins.2018.00547] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Accepted: 07/20/2018] [Indexed: 12/19/2022] Open
Abstract
Major depressive disorder (MDD) is a prevalent and debilitating disorder, often fatal. Treatment options are few and often do not provide immediate relief to the patients. The increasing involvement of inflammation in the pathology of MDD has provided new potential therapeutic avenues. Cytokine levels are elevated in the blood and cerebrospinal fluid of MDD patients whereas immune cells often exhibit an immunosuppressed phenotype in MDD patients. Blocking cytokine actions in patients exhibiting MDD show some antidepressant efficacy. However, the role of cytokines, and the immune response in MDD patients remain to be determined. We reviewed here the roles of the innate and adaptive immune systems in MDD, as well as potential mechanisms whereby the immune response might be regulated in MDD.
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Affiliation(s)
- Eva M Medina-Rodriguez
- Department of Psychiatry and Behavioral Sciences, Miller School of Medicine, University of Miami, Miami, FL, United States
| | - Jeffrey A Lowell
- Department of Psychiatry and Behavioral Sciences, Miller School of Medicine, University of Miami, Miami, FL, United States
| | - Ryan J Worthen
- Department of Psychiatry and Behavioral Sciences, Miller School of Medicine, University of Miami, Miami, FL, United States
| | - Shariful A Syed
- Department of Psychiatry and Behavioral Sciences, Miller School of Medicine, University of Miami, Miami, FL, United States
| | - Eléonore Beurel
- Department of Psychiatry and Behavioral Sciences, Miller School of Medicine, University of Miami, Miami, FL, United States.,Department of Biochemistry and Molecular Biology, Miller School of Medicine, University of Miami, Miami, FL, United States
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149
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Mukai T, Kinboshi M, Nagao Y, Shimizu S, Ono A, Sakagami Y, Okuda A, Fujimoto M, Ito H, Ikeda A, Ohno Y. Antiepileptic Drugs Elevate Astrocytic Kir4.1 Expression in the Rat Limbic Region. Front Pharmacol 2018; 9:845. [PMID: 30127740 PMCID: PMC6088221 DOI: 10.3389/fphar.2018.00845] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2018] [Accepted: 07/13/2018] [Indexed: 11/20/2022] Open
Abstract
Inwardly rectifying potassium (Kir) channel subunits Kir4.1 are specifically expressed in astrocytes and regulate neuronal excitability by mediating spatial potassium buffering. In addition, it is now known that astrocytic Kir4.1 channels are closely involved in the pathogenesis of epilepsy. Here, to explore the role of Kir4.1 channels in the treatment of epilepsy, we evaluated the effects of the antiepileptic drugs, valproate, phenytoin, phenobarbital and ethosuximide, on Kir4.1 expression in astrocytes using immunohistochemical techniques. Repeated treatment of rats with valproate (30–300 mg/kg, i.p., for 1–10 days) significantly elevated the Kir4.1 expression levels in the cerebral cortex, amygdala and hippocampus. Up-regulation of Kir4.1 expression by valproate occurred in a dose- and treatment period-related manner, and did not accompany an increase in the number of astrocytes probed by glial fibrillary acidic protein (GFAP). In addition, repeated treatment with phenytoin (30 mg/kg, i.p., for 10 days) or phenobarbital (30 mg/kg, i.p., for 10 days) also elevated Kir4.1 expression region-specifically in the amygdala. However, ethosuximide (100 mg/kg, i.p., for 10 days), which can alleviate absence but not convulsive seizures, showed no effects on the astrocytic Kir4.1 expression. The present results demonstrated for the first time that the antiepileptic drugs effective for convulsive seizures (valproate, phenytoin, and phenobarbital) commonly elevate the astrocytic Kir4.1 channel expression in the limbic regions, which may be related to their antiepileptic actions.
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Affiliation(s)
- Takahiro Mukai
- Department of Pharmacology, Osaka University of Pharmaceutical Sciences, Takatsuki, Japan
| | - Masato Kinboshi
- Department of Pharmacology, Osaka University of Pharmaceutical Sciences, Takatsuki, Japan.,Department of Neurology, Wakayama Medical University, Wakayama, Japan.,Department of Epilepsy, Movement Disorders and Physiology, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Yuki Nagao
- Department of Pharmacology, Osaka University of Pharmaceutical Sciences, Takatsuki, Japan
| | - Saki Shimizu
- Department of Pharmacology, Osaka University of Pharmaceutical Sciences, Takatsuki, Japan
| | - Asuka Ono
- Department of Pharmacology, Osaka University of Pharmaceutical Sciences, Takatsuki, Japan
| | - Yoshihisa Sakagami
- Department of Pharmacology, Osaka University of Pharmaceutical Sciences, Takatsuki, Japan
| | - Aoi Okuda
- Department of Pharmacology, Osaka University of Pharmaceutical Sciences, Takatsuki, Japan
| | - Megumi Fujimoto
- Department of Pharmacology, Osaka University of Pharmaceutical Sciences, Takatsuki, Japan
| | - Hidefumi Ito
- Department of Neurology, Wakayama Medical University, Wakayama, Japan
| | - Akio Ikeda
- Department of Epilepsy, Movement Disorders and Physiology, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Yukihiro Ohno
- Department of Pharmacology, Osaka University of Pharmaceutical Sciences, Takatsuki, Japan
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150
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Weekman EM, Woolums AE, Sudduth TL, Wilcock DM. Hyperhomocysteinemia-Induced Gene Expression Changes in the Cell Types of the Brain. ASN Neuro 2018; 9:1759091417742296. [PMID: 29198136 PMCID: PMC5718317 DOI: 10.1177/1759091417742296] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
High plasma levels of homocysteine, termed hyperhomocysteinemia, are a risk factor for vascular cognitive impairment and dementia, which is the second leading cause of dementia. While hyperhomocysteinemia induces microhemorrhages and cognitive decline in mice, the specific effect of hyperhomocysteinemia on each cell type remains unknown. We took separate cultures of astrocytes, microglia, endothelial cells, and neuronal cells and treated each with moderate levels of homocysteine for 24, 48, 72, and 96 hr. We then determined the gene expression changes for cell-specific markers and neuroinflammatory markers including the matrix metalloproteinase 9 system. Astrocytes had decreased levels of several astrocytic end feet genes, such as aquaporin 4 and an adenosine triphosphate (ATP)-sensitive inward rectifier potassium channel at 72 hr, as well as an increase in matrix metalloproteinase 9 at 48 hr. Gene changes in microglia indicated a peak in proinflammatory markers at 48 hr followed by a peak in the anti-inflammatory marker, interleukin 1 receptor antagonist, at 72 hr. Endothelial cells had reduced occludin expression at 72 hr, while kinases and phosphatases known to alter tau phosphorylation states were increased in neuronal cells. This suggests that hyperhomocysteinemia induces early proinflammatory changes in microglia and astrocytic changes relevant to their interaction with the vasculature. Overall, the data show how hyperhomocysteinemia could impact Alzheimer’s disease and vascular cognitive impairment and dementia.
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Affiliation(s)
- Erica M Weekman
- 1 Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, USA.,2 Department of Physiology, University of Kentucky, Lexington, KY, USA
| | - Abigail E Woolums
- 1 Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, USA
| | - Tiffany L Sudduth
- 1 Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, USA
| | - Donna M Wilcock
- 1 Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, USA.,2 Department of Physiology, University of Kentucky, Lexington, KY, USA
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