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Dadwal S, Heneka MT. Microglia heterogeneity in health and disease. FEBS Open Bio 2024; 14:217-229. [PMID: 37945346 PMCID: PMC10839410 DOI: 10.1002/2211-5463.13735] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Revised: 10/12/2023] [Accepted: 11/08/2023] [Indexed: 11/12/2023] Open
Abstract
Microglia, the resident immune cells of the central nervous system (CNS), have received significant attention due to their critical roles in maintaining brain homeostasis and mediating cerebral immune responses. Understanding the origin of microglia has been a subject of great interest, and emerging evidence suggests that microglia consist of multiple subpopulations with unique molecular and functional characteristics. These subpopulations of microglia may exhibit specialized roles in response to different environmental cues as in disease conditions. The newfound understanding of microglial heterogeneity has significant implications for elucidating their roles in both physiological and pathological conditions. In the context of disease, microglia have been studied rigorously as they play a very important role in neuroinflammation. Dysregulated microglial activation and function contribute to chronic inflammation. Further exploration of microglial heterogeneity and their interactions with other cell types in the CNS will undoubtedly pave the way to novel therapeutic strategies targeting microglia-mediated pathologies. In this review, we discuss the latest advances in the field of microglia research, focusing specifically on the origin and subpopulations of microglia, the populations of microglia types in the brains of patients with neurodegenerative diseases, and how microglia are regulated in the healthy CNS.
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Affiliation(s)
- Shilauni Dadwal
- Luxembourg Centre for Systems BiomedicineUniversity of LuxembourgBelvalLuxembourg
| | - Michael T. Heneka
- Luxembourg Centre for Systems BiomedicineUniversity of LuxembourgBelvalLuxembourg
- Division of Infectious Diseases and ImmunologyUniversity of Massachusetts Medical SchoolWorcesterMAUSA
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Atallah M, Yamashita T, Hu X, Hu X, Abe K. Edaravone Confers Neuroprotective, Anti-inflammatory, and Antioxidant Effects on the Fetal Brain of a Placental-ischemia Mouse Model. J Neuroimmune Pharmacol 2023; 18:640-656. [PMID: 37924374 DOI: 10.1007/s11481-023-10095-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Accepted: 10/22/2023] [Indexed: 11/06/2023]
Abstract
Reduced uterine perfusion pressure (RUPP) is a well-established model which mimics many clinical features of preeclampsia (PE). Edaravone is a free radical scavenger with neuroprotective, antioxidant and anti-inflammatory effects against different models of cerebral ischemia. Therefore, we aimed to elucidate the different potential mechanisms through which PE affects fetal brain development using our previously established RUPP-placental ischemia mouse model. In addition, we investigated the neuroprotective effect of edaravone against the RUPP-induced fetal brain development alterations. On gestation day (GD) 13, pregnant mice were divided into four groups; sham (SV), edaravone (SE), RUPP (RV), and RUPP+edaravone (RE). SV and SE groups underwent sham surgeries, however, RV and RE groups were subjected to RUPP surgery via bilateral uterine ligation. Edaravone (3mg/kg) was injected via tail i.v. injection from GD 14-18. The fetal brains from different groups were collected on GD 18 and subjected to further investigations. The results showed that RUPP altered the structure of fetal brain cortex, induced neurodegeneration, increased the expression of the investigated pro-inflammatory markers; TNF-α, IL-6, IL-1β, and MMP-9. RUPP resulted in microglial and astrocyte activation in the fetal brains, in addition to upregulation of Hif-1α and iNOS. Edaravone conferred a neuroprotective effect via alleviating the inflammatory response, restoring the neuronal structure and decreasing oxidative stress in the developing fetal brain. In conclusion, RUPP-placental ischemia mouse model could be a useful tool to further understand the underlying mechanisms of PE-induced child neuronal alterations. Edaravone could be a potential adjuvant therapy during PE to protect the developing fetal brain. The current study investigated the effects of a placenta-induced ischemia mouse model using reduced uterine perfusion pressure (RUPP) surgery on the fetal brain development and the potential neuroprotective effects of the drug edaravone. The study found that the RUPP model caused neurodegeneration and a pro-inflammatory response in the developing fetal brain, as well as hypoxia and oxidative stress. However, maternal injection of edaravone showed a strong ability to protect against these detrimental effects and target multiple pathways associated with neuronal damage. The current study suggests that the RUPP model could be useful for further study of the impact of preeclampsia on fetal brain development and that edaravone may have potential as a therapy for protecting against this damage.
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Affiliation(s)
- Marwa Atallah
- Vertebrates Comparative Anatomy and Embryology, Zoology Department, Faculty of Science, Menoufia University, Shibin El-Koom, Egypt.
| | - Toru Yamashita
- Department of Neurology, Dentistry and Pharmaceutical Sciences, Okayama University Graduate School of Medicine, Okayama, Japan
| | - Xiao Hu
- Department of Neurology, Dentistry and Pharmaceutical Sciences, Okayama University Graduate School of Medicine, Okayama, Japan
| | - Xinran Hu
- Department of Neurology, Dentistry and Pharmaceutical Sciences, Okayama University Graduate School of Medicine, Okayama, Japan
| | - Koji Abe
- Department of Neurology, Dentistry and Pharmaceutical Sciences, Okayama University Graduate School of Medicine, Okayama, Japan
- National Center of Neurology and Psychiatry (NCNP), National Center Hospital, Tokyo, Japan
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Non-competitive AMPA glutamate receptors antagonism by perampanel as a strategy to counteract hippocampal hyper-excitability and cognitive deficits in cerebral amyloidosis. Neuropharmacology 2023; 225:109373. [PMID: 36502868 DOI: 10.1016/j.neuropharm.2022.109373] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2022] [Revised: 11/26/2022] [Accepted: 12/07/2022] [Indexed: 12/14/2022]
Abstract
Pathological accumulation of Aβ oligomers has been linked to neuronal networks hyperexcitability, potentially underpinned by glutamatergic AMPA receptors (AMPARs) dysfunction. We aimed to investigate whether the non-competitive block of AMPARs was able to counteract the alteration of hippocampal epileptic threshold, and of synaptic plasticity linked to Aβ oligomers accumulation, being this glutamate receptor a valuable specific therapeutic target. In this work, we showed that the non-competitive AMPARs antagonist perampanel (PER) which, per se, did not affect physiological synaptic transmission, was able to counteract Aβ-induced hyperexcitability. Moreover, AMPAR antagonism was able to counteract Aβ-induced hippocampal LTP impairment and hippocampal-based cognitive deficits in Aβ oligomers-injected mice, while retaining antiseizure efficacy. Beside this, AMPAR antagonism was also able to reduce the increased expression of proinflammatory cytokines in this mice model, also suggesting the presence of an anti-inflammatory activity. Thus, targeting AMPARs might be a valuable strategy to reduce both hippocampal networks hyperexcitability and synaptic plasticity deficits induced by Aβ oligomers accumulation.
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Inhibiting miR-186-5p relieves traumatic brain injury by regulating insulin-like growth factor-I-NLRP3/ASC/caspase-1 signaling pathway. Neuroreport 2023; 34:156-164. [PMID: 36719839 DOI: 10.1097/wnr.0000000000001873] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Previous studies have shown that micro-RNA (miR)-186-5p can affect apoptosis of cells by regulating insulin-like growth factor-I (IGF-1). However, the role of miR-186-5p-IGF1 axis in traumatic brain injury (TBI), especially oxidative stress and neuroinflammatory response, remains to be further studied. Lipopolysaccharide (5 μg/mL) was used to activate microglia in vitro . The expression of miR-186-5p, IGF-1 was detected by quantitative reverse transcription PCR (qRT-PCR). ELISA and western blot were used to detect the inflammatory factors and oxidative stress. Western blot was used to detect apoptotic proteins (Bax, Bcl2 and C-caspase3), inflammatory proteins (iNOS and COX2), oxidative stress proteins (Nrf2 and HO-1) and NLRP3/apoptosis-associated speck-like protein containing a CARD (ASC)/caspase-1 inflammatory bodies. MiR-186-5p inhibitor could reduce the inflammatory factors and oxidative stress in BV2 treated with lipopolysaccharide, and reduce apoptosis. In addition, we also found that inhibition of miR-186-5p increased the expression of IGF-1, which is necessary for nervous system development. Luciferase activity assay confirmed that IGF-1 was the direct target gene of miR-186-5p. Inhibiting miR-186-5p, through upregulation IGF-1, attenuates the inflammatory factors, oxidative stress and by inhibiting NLRP3/ASC/caspase-1 signal pathway TBI in-vitro model.
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Ji N, Lei M, Chen Y, Tian S, Li C, Zhang B. How Oxidative Stress Induces Depression? ASN Neuro 2023; 15:17590914231181037. [PMID: 37331994 DOI: 10.1177/17590914231181037] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/20/2023] Open
Abstract
Depression increasingly affects a wide range and a large number of people worldwide, both physically and psychologically, which makes it a social problem requiring prompt attention and management. Accumulating clinical and animal studies have provided us with substantial insights of disease pathogenesis, especially central monoamine deficiency, which considerably promotes antidepressant research and clinical treatment. The first-line antidepressants mainly target the monoamine system, whose drawbacks mainly include slow action and treatment resistant. The novel antidepressant esketamine, targeting on central glutamatergic system, rapidly and robustly alleviates depression (including treatment-resistant depression), whose efficiency is shadowed by potential addictive and psychotomimetic side effects. Thus, exploring novel depression pathogenesis is necessary, for seeking more safe and effective therapeutic methods. Emerging evidence has revealed vital involvement of oxidative stress (OS) in depression, which inspires us to pursue antioxidant pathway for depression prevention and treatment. Fully uncovering the underlying mechanisms of OS-induced depression is the first step towards the avenue, thus we summarize and expound possible downstream pathways of OS, including mitochondrial impairment and related ATP deficiency, neuroinflammation, central glutamate excitotoxicity, brain-derived neurotrophic factor/tyrosine receptor kinase B dysfunction and serotonin deficiency, the microbiota-gut-brain axis disturbance and hypothalamic-pituitary-adrenocortical axis dysregulation. We also elaborate on the intricate interactions between the multiple aspects, and molecular mechanisms mediating the interplay. Through reviewing the related research progress in the field, we hope to depict an integral overview of how OS induces depression, in order to provide fresh ideas and novel targets for the final goal of efficient treatment of the disease.
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Affiliation(s)
- Na Ji
- The School of Public Health, Faculty of Basic Medical Sciences, Guangxi Key Laboratory of Brain and Cognitive Neuroscience, Guilin Medical University, Guilin Guangxi, China
| | - Mengzhu Lei
- The School of Public Health, Faculty of Basic Medical Sciences, Guangxi Key Laboratory of Brain and Cognitive Neuroscience, Guilin Medical University, Guilin Guangxi, China
| | - Yating Chen
- The School of Public Health, Faculty of Basic Medical Sciences, Guangxi Key Laboratory of Brain and Cognitive Neuroscience, Guilin Medical University, Guilin Guangxi, China
| | - Shaowen Tian
- The School of Public Health, Faculty of Basic Medical Sciences, Guangxi Key Laboratory of Brain and Cognitive Neuroscience, Guilin Medical University, Guilin Guangxi, China
| | - Chuanyu Li
- The School of Public Health, Faculty of Basic Medical Sciences, Guilin Medical University, Guilin Guangxi, China
| | - Bo Zhang
- The School of Public Health, Faculty of Basic Medical Sciences, Guangxi Key Laboratory of Brain and Cognitive Neuroscience, Guilin Medical University, Guilin Guangxi, China
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Research Progress on Neuroprotection of Insulin-like Growth Factor-1 towards Glutamate-Induced Neurotoxicity. Cells 2022; 11:cells11040666. [PMID: 35203315 PMCID: PMC8870287 DOI: 10.3390/cells11040666] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2021] [Revised: 02/05/2022] [Accepted: 02/11/2022] [Indexed: 02/01/2023] Open
Abstract
Insulin-like growth factor-1 (IGF-1) and its binding proteins and receptors are widely expressed in the central nervous system (CNS), proposing IGF-1-induced neurotrophic actions in normal growth, development, and maintenance. However, while there is convincing evidence that the IGF-1 system has specific endocrine roles in the CNS, the concept is emerging that IGF-I might be also important in disorders such as ischemic stroke, brain trauma, Alzheimer’s disease, epilepsy, etc., by inducing neuroprotective effects towards glutamate-mediated excitotoxic signaling pathways. Research in rodent models has demonstrated rescue of pathophysiological and behavioral abnormalities when IGF-1 was administered by different routes, and several clinical studies have shown safety and promise of efficacy in neurological disorders of the CNS. Focusing on the relationship between IGF-1-induced neuroprotection and glutamate-induced excitatory neurotoxicity, this review addresses the research progress in the field, intending to provide a rationale for using IGF-I clinically to confer neuroprotective therapy towards neurological diseases with glutamate excitotoxicity as a common pathological pathway.
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Hansen KB, Wollmuth LP, Bowie D, Furukawa H, Menniti FS, Sobolevsky AI, Swanson GT, Swanger SA, Greger IH, Nakagawa T, McBain CJ, Jayaraman V, Low CM, Dell'Acqua ML, Diamond JS, Camp CR, Perszyk RE, Yuan H, Traynelis SF. Structure, Function, and Pharmacology of Glutamate Receptor Ion Channels. Pharmacol Rev 2021; 73:298-487. [PMID: 34753794 PMCID: PMC8626789 DOI: 10.1124/pharmrev.120.000131] [Citation(s) in RCA: 236] [Impact Index Per Article: 78.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Many physiologic effects of l-glutamate, the major excitatory neurotransmitter in the mammalian central nervous system, are mediated via signaling by ionotropic glutamate receptors (iGluRs). These ligand-gated ion channels are critical to brain function and are centrally implicated in numerous psychiatric and neurologic disorders. There are different classes of iGluRs with a variety of receptor subtypes in each class that play distinct roles in neuronal functions. The diversity in iGluR subtypes, with their unique functional properties and physiologic roles, has motivated a large number of studies. Our understanding of receptor subtypes has advanced considerably since the first iGluR subunit gene was cloned in 1989, and the research focus has expanded to encompass facets of biology that have been recently discovered and to exploit experimental paradigms made possible by technological advances. Here, we review insights from more than 3 decades of iGluR studies with an emphasis on the progress that has occurred in the past decade. We cover structure, function, pharmacology, roles in neurophysiology, and therapeutic implications for all classes of receptors assembled from the subunits encoded by the 18 ionotropic glutamate receptor genes. SIGNIFICANCE STATEMENT: Glutamate receptors play important roles in virtually all aspects of brain function and are either involved in mediating some clinical features of neurological disease or represent a therapeutic target for treatment. Therefore, understanding the structure, function, and pharmacology of this class of receptors will advance our understanding of many aspects of brain function at molecular, cellular, and system levels and provide new opportunities to treat patients.
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Affiliation(s)
- Kasper B Hansen
- Center for Structural and Functional Neuroscience, Center for Biomolecular Structure and Dynamics, Division of Biological Sciences, University of Montana, Missoula, MT (K.B.H.); Department of Neurobiology and Behavior, Center for Nervous System Disorders, Stony Brook University, Stony Brook, NY (L.P.W.); Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec, Canada (D.B.); WM Keck Structural Biology Laboratory, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY (H.F.); MindImmune Therapeutics, Inc., The George & Anne Ryan Institute for Neuroscience, University of Rhode Island, Kingston, RI (F.S.M.); Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY (A.I.S.); Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL (G.T.S.); Fralin Biomedical Research Institute at Virginia Tech Carilion, Virginia Tech, Roanoke, VA and Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, VA (S.A.S.); Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom (I.H.G.); Department of Molecular Physiology and Biophysics, Center for Structural Biology, Vanderbilt Brain Institute, Vanderbilt University, School of Medicine, Nashville, TN (T.N.); Eunice Kennedy Shriver National Institute of Child Health and Human Development (C.J.M.), and Synaptic Physiology Section, NINDS Intramural Research Program, National Institutes of Health, Bethesda, MD (J.S.D.); Department of Biochemistry and Molecular Biology, University of Texas Health Science Center, Houston, TX (V.J.); Department of Pharmacology, Department of Anaesthesia, Healthy Longevity Translational Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore (C.-M.L.); Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO (M.L.D.); and Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, GA (C.R.C., R.E.P., H.Y., S.F.T.)
| | - Lonnie P Wollmuth
- Center for Structural and Functional Neuroscience, Center for Biomolecular Structure and Dynamics, Division of Biological Sciences, University of Montana, Missoula, MT (K.B.H.); Department of Neurobiology and Behavior, Center for Nervous System Disorders, Stony Brook University, Stony Brook, NY (L.P.W.); Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec, Canada (D.B.); WM Keck Structural Biology Laboratory, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY (H.F.); MindImmune Therapeutics, Inc., The George & Anne Ryan Institute for Neuroscience, University of Rhode Island, Kingston, RI (F.S.M.); Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY (A.I.S.); Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL (G.T.S.); Fralin Biomedical Research Institute at Virginia Tech Carilion, Virginia Tech, Roanoke, VA and Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, VA (S.A.S.); Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom (I.H.G.); Department of Molecular Physiology and Biophysics, Center for Structural Biology, Vanderbilt Brain Institute, Vanderbilt University, School of Medicine, Nashville, TN (T.N.); Eunice Kennedy Shriver National Institute of Child Health and Human Development (C.J.M.), and Synaptic Physiology Section, NINDS Intramural Research Program, National Institutes of Health, Bethesda, MD (J.S.D.); Department of Biochemistry and Molecular Biology, University of Texas Health Science Center, Houston, TX (V.J.); Department of Pharmacology, Department of Anaesthesia, Healthy Longevity Translational Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore (C.-M.L.); Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO (M.L.D.); and Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, GA (C.R.C., R.E.P., H.Y., S.F.T.)
| | - Derek Bowie
- Center for Structural and Functional Neuroscience, Center for Biomolecular Structure and Dynamics, Division of Biological Sciences, University of Montana, Missoula, MT (K.B.H.); Department of Neurobiology and Behavior, Center for Nervous System Disorders, Stony Brook University, Stony Brook, NY (L.P.W.); Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec, Canada (D.B.); WM Keck Structural Biology Laboratory, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY (H.F.); MindImmune Therapeutics, Inc., The George & Anne Ryan Institute for Neuroscience, University of Rhode Island, Kingston, RI (F.S.M.); Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY (A.I.S.); Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL (G.T.S.); Fralin Biomedical Research Institute at Virginia Tech Carilion, Virginia Tech, Roanoke, VA and Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, VA (S.A.S.); Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom (I.H.G.); Department of Molecular Physiology and Biophysics, Center for Structural Biology, Vanderbilt Brain Institute, Vanderbilt University, School of Medicine, Nashville, TN (T.N.); Eunice Kennedy Shriver National Institute of Child Health and Human Development (C.J.M.), and Synaptic Physiology Section, NINDS Intramural Research Program, National Institutes of Health, Bethesda, MD (J.S.D.); Department of Biochemistry and Molecular Biology, University of Texas Health Science Center, Houston, TX (V.J.); Department of Pharmacology, Department of Anaesthesia, Healthy Longevity Translational Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore (C.-M.L.); Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO (M.L.D.); and Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, GA (C.R.C., R.E.P., H.Y., S.F.T.)
| | - Hiro Furukawa
- Center for Structural and Functional Neuroscience, Center for Biomolecular Structure and Dynamics, Division of Biological Sciences, University of Montana, Missoula, MT (K.B.H.); Department of Neurobiology and Behavior, Center for Nervous System Disorders, Stony Brook University, Stony Brook, NY (L.P.W.); Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec, Canada (D.B.); WM Keck Structural Biology Laboratory, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY (H.F.); MindImmune Therapeutics, Inc., The George & Anne Ryan Institute for Neuroscience, University of Rhode Island, Kingston, RI (F.S.M.); Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY (A.I.S.); Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL (G.T.S.); Fralin Biomedical Research Institute at Virginia Tech Carilion, Virginia Tech, Roanoke, VA and Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, VA (S.A.S.); Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom (I.H.G.); Department of Molecular Physiology and Biophysics, Center for Structural Biology, Vanderbilt Brain Institute, Vanderbilt University, School of Medicine, Nashville, TN (T.N.); Eunice Kennedy Shriver National Institute of Child Health and Human Development (C.J.M.), and Synaptic Physiology Section, NINDS Intramural Research Program, National Institutes of Health, Bethesda, MD (J.S.D.); Department of Biochemistry and Molecular Biology, University of Texas Health Science Center, Houston, TX (V.J.); Department of Pharmacology, Department of Anaesthesia, Healthy Longevity Translational Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore (C.-M.L.); Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO (M.L.D.); and Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, GA (C.R.C., R.E.P., H.Y., S.F.T.)
| | - Frank S Menniti
- Center for Structural and Functional Neuroscience, Center for Biomolecular Structure and Dynamics, Division of Biological Sciences, University of Montana, Missoula, MT (K.B.H.); Department of Neurobiology and Behavior, Center for Nervous System Disorders, Stony Brook University, Stony Brook, NY (L.P.W.); Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec, Canada (D.B.); WM Keck Structural Biology Laboratory, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY (H.F.); MindImmune Therapeutics, Inc., The George & Anne Ryan Institute for Neuroscience, University of Rhode Island, Kingston, RI (F.S.M.); Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY (A.I.S.); Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL (G.T.S.); Fralin Biomedical Research Institute at Virginia Tech Carilion, Virginia Tech, Roanoke, VA and Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, VA (S.A.S.); Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom (I.H.G.); Department of Molecular Physiology and Biophysics, Center for Structural Biology, Vanderbilt Brain Institute, Vanderbilt University, School of Medicine, Nashville, TN (T.N.); Eunice Kennedy Shriver National Institute of Child Health and Human Development (C.J.M.), and Synaptic Physiology Section, NINDS Intramural Research Program, National Institutes of Health, Bethesda, MD (J.S.D.); Department of Biochemistry and Molecular Biology, University of Texas Health Science Center, Houston, TX (V.J.); Department of Pharmacology, Department of Anaesthesia, Healthy Longevity Translational Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore (C.-M.L.); Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO (M.L.D.); and Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, GA (C.R.C., R.E.P., H.Y., S.F.T.)
| | - Alexander I Sobolevsky
- Center for Structural and Functional Neuroscience, Center for Biomolecular Structure and Dynamics, Division of Biological Sciences, University of Montana, Missoula, MT (K.B.H.); Department of Neurobiology and Behavior, Center for Nervous System Disorders, Stony Brook University, Stony Brook, NY (L.P.W.); Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec, Canada (D.B.); WM Keck Structural Biology Laboratory, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY (H.F.); MindImmune Therapeutics, Inc., The George & Anne Ryan Institute for Neuroscience, University of Rhode Island, Kingston, RI (F.S.M.); Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY (A.I.S.); Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL (G.T.S.); Fralin Biomedical Research Institute at Virginia Tech Carilion, Virginia Tech, Roanoke, VA and Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, VA (S.A.S.); Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom (I.H.G.); Department of Molecular Physiology and Biophysics, Center for Structural Biology, Vanderbilt Brain Institute, Vanderbilt University, School of Medicine, Nashville, TN (T.N.); Eunice Kennedy Shriver National Institute of Child Health and Human Development (C.J.M.), and Synaptic Physiology Section, NINDS Intramural Research Program, National Institutes of Health, Bethesda, MD (J.S.D.); Department of Biochemistry and Molecular Biology, University of Texas Health Science Center, Houston, TX (V.J.); Department of Pharmacology, Department of Anaesthesia, Healthy Longevity Translational Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore (C.-M.L.); Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO (M.L.D.); and Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, GA (C.R.C., R.E.P., H.Y., S.F.T.)
| | - Geoffrey T Swanson
- Center for Structural and Functional Neuroscience, Center for Biomolecular Structure and Dynamics, Division of Biological Sciences, University of Montana, Missoula, MT (K.B.H.); Department of Neurobiology and Behavior, Center for Nervous System Disorders, Stony Brook University, Stony Brook, NY (L.P.W.); Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec, Canada (D.B.); WM Keck Structural Biology Laboratory, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY (H.F.); MindImmune Therapeutics, Inc., The George & Anne Ryan Institute for Neuroscience, University of Rhode Island, Kingston, RI (F.S.M.); Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY (A.I.S.); Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL (G.T.S.); Fralin Biomedical Research Institute at Virginia Tech Carilion, Virginia Tech, Roanoke, VA and Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, VA (S.A.S.); Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom (I.H.G.); Department of Molecular Physiology and Biophysics, Center for Structural Biology, Vanderbilt Brain Institute, Vanderbilt University, School of Medicine, Nashville, TN (T.N.); Eunice Kennedy Shriver National Institute of Child Health and Human Development (C.J.M.), and Synaptic Physiology Section, NINDS Intramural Research Program, National Institutes of Health, Bethesda, MD (J.S.D.); Department of Biochemistry and Molecular Biology, University of Texas Health Science Center, Houston, TX (V.J.); Department of Pharmacology, Department of Anaesthesia, Healthy Longevity Translational Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore (C.-M.L.); Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO (M.L.D.); and Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, GA (C.R.C., R.E.P., H.Y., S.F.T.)
| | - Sharon A Swanger
- Center for Structural and Functional Neuroscience, Center for Biomolecular Structure and Dynamics, Division of Biological Sciences, University of Montana, Missoula, MT (K.B.H.); Department of Neurobiology and Behavior, Center for Nervous System Disorders, Stony Brook University, Stony Brook, NY (L.P.W.); Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec, Canada (D.B.); WM Keck Structural Biology Laboratory, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY (H.F.); MindImmune Therapeutics, Inc., The George & Anne Ryan Institute for Neuroscience, University of Rhode Island, Kingston, RI (F.S.M.); Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY (A.I.S.); Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL (G.T.S.); Fralin Biomedical Research Institute at Virginia Tech Carilion, Virginia Tech, Roanoke, VA and Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, VA (S.A.S.); Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom (I.H.G.); Department of Molecular Physiology and Biophysics, Center for Structural Biology, Vanderbilt Brain Institute, Vanderbilt University, School of Medicine, Nashville, TN (T.N.); Eunice Kennedy Shriver National Institute of Child Health and Human Development (C.J.M.), and Synaptic Physiology Section, NINDS Intramural Research Program, National Institutes of Health, Bethesda, MD (J.S.D.); Department of Biochemistry and Molecular Biology, University of Texas Health Science Center, Houston, TX (V.J.); Department of Pharmacology, Department of Anaesthesia, Healthy Longevity Translational Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore (C.-M.L.); Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO (M.L.D.); and Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, GA (C.R.C., R.E.P., H.Y., S.F.T.)
| | - Ingo H Greger
- Center for Structural and Functional Neuroscience, Center for Biomolecular Structure and Dynamics, Division of Biological Sciences, University of Montana, Missoula, MT (K.B.H.); Department of Neurobiology and Behavior, Center for Nervous System Disorders, Stony Brook University, Stony Brook, NY (L.P.W.); Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec, Canada (D.B.); WM Keck Structural Biology Laboratory, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY (H.F.); MindImmune Therapeutics, Inc., The George & Anne Ryan Institute for Neuroscience, University of Rhode Island, Kingston, RI (F.S.M.); Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY (A.I.S.); Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL (G.T.S.); Fralin Biomedical Research Institute at Virginia Tech Carilion, Virginia Tech, Roanoke, VA and Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, VA (S.A.S.); Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom (I.H.G.); Department of Molecular Physiology and Biophysics, Center for Structural Biology, Vanderbilt Brain Institute, Vanderbilt University, School of Medicine, Nashville, TN (T.N.); Eunice Kennedy Shriver National Institute of Child Health and Human Development (C.J.M.), and Synaptic Physiology Section, NINDS Intramural Research Program, National Institutes of Health, Bethesda, MD (J.S.D.); Department of Biochemistry and Molecular Biology, University of Texas Health Science Center, Houston, TX (V.J.); Department of Pharmacology, Department of Anaesthesia, Healthy Longevity Translational Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore (C.-M.L.); Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO (M.L.D.); and Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, GA (C.R.C., R.E.P., H.Y., S.F.T.)
| | - Terunaga Nakagawa
- Center for Structural and Functional Neuroscience, Center for Biomolecular Structure and Dynamics, Division of Biological Sciences, University of Montana, Missoula, MT (K.B.H.); Department of Neurobiology and Behavior, Center for Nervous System Disorders, Stony Brook University, Stony Brook, NY (L.P.W.); Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec, Canada (D.B.); WM Keck Structural Biology Laboratory, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY (H.F.); MindImmune Therapeutics, Inc., The George & Anne Ryan Institute for Neuroscience, University of Rhode Island, Kingston, RI (F.S.M.); Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY (A.I.S.); Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL (G.T.S.); Fralin Biomedical Research Institute at Virginia Tech Carilion, Virginia Tech, Roanoke, VA and Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, VA (S.A.S.); Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom (I.H.G.); Department of Molecular Physiology and Biophysics, Center for Structural Biology, Vanderbilt Brain Institute, Vanderbilt University, School of Medicine, Nashville, TN (T.N.); Eunice Kennedy Shriver National Institute of Child Health and Human Development (C.J.M.), and Synaptic Physiology Section, NINDS Intramural Research Program, National Institutes of Health, Bethesda, MD (J.S.D.); Department of Biochemistry and Molecular Biology, University of Texas Health Science Center, Houston, TX (V.J.); Department of Pharmacology, Department of Anaesthesia, Healthy Longevity Translational Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore (C.-M.L.); Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO (M.L.D.); and Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, GA (C.R.C., R.E.P., H.Y., S.F.T.)
| | - Chris J McBain
- Center for Structural and Functional Neuroscience, Center for Biomolecular Structure and Dynamics, Division of Biological Sciences, University of Montana, Missoula, MT (K.B.H.); Department of Neurobiology and Behavior, Center for Nervous System Disorders, Stony Brook University, Stony Brook, NY (L.P.W.); Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec, Canada (D.B.); WM Keck Structural Biology Laboratory, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY (H.F.); MindImmune Therapeutics, Inc., The George & Anne Ryan Institute for Neuroscience, University of Rhode Island, Kingston, RI (F.S.M.); Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY (A.I.S.); Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL (G.T.S.); Fralin Biomedical Research Institute at Virginia Tech Carilion, Virginia Tech, Roanoke, VA and Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, VA (S.A.S.); Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom (I.H.G.); Department of Molecular Physiology and Biophysics, Center for Structural Biology, Vanderbilt Brain Institute, Vanderbilt University, School of Medicine, Nashville, TN (T.N.); Eunice Kennedy Shriver National Institute of Child Health and Human Development (C.J.M.), and Synaptic Physiology Section, NINDS Intramural Research Program, National Institutes of Health, Bethesda, MD (J.S.D.); Department of Biochemistry and Molecular Biology, University of Texas Health Science Center, Houston, TX (V.J.); Department of Pharmacology, Department of Anaesthesia, Healthy Longevity Translational Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore (C.-M.L.); Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO (M.L.D.); and Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, GA (C.R.C., R.E.P., H.Y., S.F.T.)
| | - Vasanthi Jayaraman
- Center for Structural and Functional Neuroscience, Center for Biomolecular Structure and Dynamics, Division of Biological Sciences, University of Montana, Missoula, MT (K.B.H.); Department of Neurobiology and Behavior, Center for Nervous System Disorders, Stony Brook University, Stony Brook, NY (L.P.W.); Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec, Canada (D.B.); WM Keck Structural Biology Laboratory, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY (H.F.); MindImmune Therapeutics, Inc., The George & Anne Ryan Institute for Neuroscience, University of Rhode Island, Kingston, RI (F.S.M.); Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY (A.I.S.); Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL (G.T.S.); Fralin Biomedical Research Institute at Virginia Tech Carilion, Virginia Tech, Roanoke, VA and Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, VA (S.A.S.); Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom (I.H.G.); Department of Molecular Physiology and Biophysics, Center for Structural Biology, Vanderbilt Brain Institute, Vanderbilt University, School of Medicine, Nashville, TN (T.N.); Eunice Kennedy Shriver National Institute of Child Health and Human Development (C.J.M.), and Synaptic Physiology Section, NINDS Intramural Research Program, National Institutes of Health, Bethesda, MD (J.S.D.); Department of Biochemistry and Molecular Biology, University of Texas Health Science Center, Houston, TX (V.J.); Department of Pharmacology, Department of Anaesthesia, Healthy Longevity Translational Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore (C.-M.L.); Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO (M.L.D.); and Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, GA (C.R.C., R.E.P., H.Y., S.F.T.)
| | - Chian-Ming Low
- Center for Structural and Functional Neuroscience, Center for Biomolecular Structure and Dynamics, Division of Biological Sciences, University of Montana, Missoula, MT (K.B.H.); Department of Neurobiology and Behavior, Center for Nervous System Disorders, Stony Brook University, Stony Brook, NY (L.P.W.); Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec, Canada (D.B.); WM Keck Structural Biology Laboratory, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY (H.F.); MindImmune Therapeutics, Inc., The George & Anne Ryan Institute for Neuroscience, University of Rhode Island, Kingston, RI (F.S.M.); Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY (A.I.S.); Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL (G.T.S.); Fralin Biomedical Research Institute at Virginia Tech Carilion, Virginia Tech, Roanoke, VA and Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, VA (S.A.S.); Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom (I.H.G.); Department of Molecular Physiology and Biophysics, Center for Structural Biology, Vanderbilt Brain Institute, Vanderbilt University, School of Medicine, Nashville, TN (T.N.); Eunice Kennedy Shriver National Institute of Child Health and Human Development (C.J.M.), and Synaptic Physiology Section, NINDS Intramural Research Program, National Institutes of Health, Bethesda, MD (J.S.D.); Department of Biochemistry and Molecular Biology, University of Texas Health Science Center, Houston, TX (V.J.); Department of Pharmacology, Department of Anaesthesia, Healthy Longevity Translational Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore (C.-M.L.); Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO (M.L.D.); and Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, GA (C.R.C., R.E.P., H.Y., S.F.T.)
| | - Mark L Dell'Acqua
- Center for Structural and Functional Neuroscience, Center for Biomolecular Structure and Dynamics, Division of Biological Sciences, University of Montana, Missoula, MT (K.B.H.); Department of Neurobiology and Behavior, Center for Nervous System Disorders, Stony Brook University, Stony Brook, NY (L.P.W.); Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec, Canada (D.B.); WM Keck Structural Biology Laboratory, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY (H.F.); MindImmune Therapeutics, Inc., The George & Anne Ryan Institute for Neuroscience, University of Rhode Island, Kingston, RI (F.S.M.); Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY (A.I.S.); Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL (G.T.S.); Fralin Biomedical Research Institute at Virginia Tech Carilion, Virginia Tech, Roanoke, VA and Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, VA (S.A.S.); Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom (I.H.G.); Department of Molecular Physiology and Biophysics, Center for Structural Biology, Vanderbilt Brain Institute, Vanderbilt University, School of Medicine, Nashville, TN (T.N.); Eunice Kennedy Shriver National Institute of Child Health and Human Development (C.J.M.), and Synaptic Physiology Section, NINDS Intramural Research Program, National Institutes of Health, Bethesda, MD (J.S.D.); Department of Biochemistry and Molecular Biology, University of Texas Health Science Center, Houston, TX (V.J.); Department of Pharmacology, Department of Anaesthesia, Healthy Longevity Translational Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore (C.-M.L.); Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO (M.L.D.); and Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, GA (C.R.C., R.E.P., H.Y., S.F.T.)
| | - Jeffrey S Diamond
- Center for Structural and Functional Neuroscience, Center for Biomolecular Structure and Dynamics, Division of Biological Sciences, University of Montana, Missoula, MT (K.B.H.); Department of Neurobiology and Behavior, Center for Nervous System Disorders, Stony Brook University, Stony Brook, NY (L.P.W.); Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec, Canada (D.B.); WM Keck Structural Biology Laboratory, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY (H.F.); MindImmune Therapeutics, Inc., The George & Anne Ryan Institute for Neuroscience, University of Rhode Island, Kingston, RI (F.S.M.); Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY (A.I.S.); Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL (G.T.S.); Fralin Biomedical Research Institute at Virginia Tech Carilion, Virginia Tech, Roanoke, VA and Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, VA (S.A.S.); Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom (I.H.G.); Department of Molecular Physiology and Biophysics, Center for Structural Biology, Vanderbilt Brain Institute, Vanderbilt University, School of Medicine, Nashville, TN (T.N.); Eunice Kennedy Shriver National Institute of Child Health and Human Development (C.J.M.), and Synaptic Physiology Section, NINDS Intramural Research Program, National Institutes of Health, Bethesda, MD (J.S.D.); Department of Biochemistry and Molecular Biology, University of Texas Health Science Center, Houston, TX (V.J.); Department of Pharmacology, Department of Anaesthesia, Healthy Longevity Translational Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore (C.-M.L.); Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO (M.L.D.); and Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, GA (C.R.C., R.E.P., H.Y., S.F.T.)
| | - Chad R Camp
- Center for Structural and Functional Neuroscience, Center for Biomolecular Structure and Dynamics, Division of Biological Sciences, University of Montana, Missoula, MT (K.B.H.); Department of Neurobiology and Behavior, Center for Nervous System Disorders, Stony Brook University, Stony Brook, NY (L.P.W.); Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec, Canada (D.B.); WM Keck Structural Biology Laboratory, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY (H.F.); MindImmune Therapeutics, Inc., The George & Anne Ryan Institute for Neuroscience, University of Rhode Island, Kingston, RI (F.S.M.); Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY (A.I.S.); Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL (G.T.S.); Fralin Biomedical Research Institute at Virginia Tech Carilion, Virginia Tech, Roanoke, VA and Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, VA (S.A.S.); Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom (I.H.G.); Department of Molecular Physiology and Biophysics, Center for Structural Biology, Vanderbilt Brain Institute, Vanderbilt University, School of Medicine, Nashville, TN (T.N.); Eunice Kennedy Shriver National Institute of Child Health and Human Development (C.J.M.), and Synaptic Physiology Section, NINDS Intramural Research Program, National Institutes of Health, Bethesda, MD (J.S.D.); Department of Biochemistry and Molecular Biology, University of Texas Health Science Center, Houston, TX (V.J.); Department of Pharmacology, Department of Anaesthesia, Healthy Longevity Translational Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore (C.-M.L.); Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO (M.L.D.); and Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, GA (C.R.C., R.E.P., H.Y., S.F.T.)
| | - Riley E Perszyk
- Center for Structural and Functional Neuroscience, Center for Biomolecular Structure and Dynamics, Division of Biological Sciences, University of Montana, Missoula, MT (K.B.H.); Department of Neurobiology and Behavior, Center for Nervous System Disorders, Stony Brook University, Stony Brook, NY (L.P.W.); Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec, Canada (D.B.); WM Keck Structural Biology Laboratory, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY (H.F.); MindImmune Therapeutics, Inc., The George & Anne Ryan Institute for Neuroscience, University of Rhode Island, Kingston, RI (F.S.M.); Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY (A.I.S.); Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL (G.T.S.); Fralin Biomedical Research Institute at Virginia Tech Carilion, Virginia Tech, Roanoke, VA and Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, VA (S.A.S.); Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom (I.H.G.); Department of Molecular Physiology and Biophysics, Center for Structural Biology, Vanderbilt Brain Institute, Vanderbilt University, School of Medicine, Nashville, TN (T.N.); Eunice Kennedy Shriver National Institute of Child Health and Human Development (C.J.M.), and Synaptic Physiology Section, NINDS Intramural Research Program, National Institutes of Health, Bethesda, MD (J.S.D.); Department of Biochemistry and Molecular Biology, University of Texas Health Science Center, Houston, TX (V.J.); Department of Pharmacology, Department of Anaesthesia, Healthy Longevity Translational Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore (C.-M.L.); Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO (M.L.D.); and Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, GA (C.R.C., R.E.P., H.Y., S.F.T.)
| | - Hongjie Yuan
- Center for Structural and Functional Neuroscience, Center for Biomolecular Structure and Dynamics, Division of Biological Sciences, University of Montana, Missoula, MT (K.B.H.); Department of Neurobiology and Behavior, Center for Nervous System Disorders, Stony Brook University, Stony Brook, NY (L.P.W.); Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec, Canada (D.B.); WM Keck Structural Biology Laboratory, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY (H.F.); MindImmune Therapeutics, Inc., The George & Anne Ryan Institute for Neuroscience, University of Rhode Island, Kingston, RI (F.S.M.); Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY (A.I.S.); Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL (G.T.S.); Fralin Biomedical Research Institute at Virginia Tech Carilion, Virginia Tech, Roanoke, VA and Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, VA (S.A.S.); Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom (I.H.G.); Department of Molecular Physiology and Biophysics, Center for Structural Biology, Vanderbilt Brain Institute, Vanderbilt University, School of Medicine, Nashville, TN (T.N.); Eunice Kennedy Shriver National Institute of Child Health and Human Development (C.J.M.), and Synaptic Physiology Section, NINDS Intramural Research Program, National Institutes of Health, Bethesda, MD (J.S.D.); Department of Biochemistry and Molecular Biology, University of Texas Health Science Center, Houston, TX (V.J.); Department of Pharmacology, Department of Anaesthesia, Healthy Longevity Translational Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore (C.-M.L.); Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO (M.L.D.); and Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, GA (C.R.C., R.E.P., H.Y., S.F.T.)
| | - Stephen F Traynelis
- Center for Structural and Functional Neuroscience, Center for Biomolecular Structure and Dynamics, Division of Biological Sciences, University of Montana, Missoula, MT (K.B.H.); Department of Neurobiology and Behavior, Center for Nervous System Disorders, Stony Brook University, Stony Brook, NY (L.P.W.); Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec, Canada (D.B.); WM Keck Structural Biology Laboratory, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY (H.F.); MindImmune Therapeutics, Inc., The George & Anne Ryan Institute for Neuroscience, University of Rhode Island, Kingston, RI (F.S.M.); Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY (A.I.S.); Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL (G.T.S.); Fralin Biomedical Research Institute at Virginia Tech Carilion, Virginia Tech, Roanoke, VA and Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, VA (S.A.S.); Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom (I.H.G.); Department of Molecular Physiology and Biophysics, Center for Structural Biology, Vanderbilt Brain Institute, Vanderbilt University, School of Medicine, Nashville, TN (T.N.); Eunice Kennedy Shriver National Institute of Child Health and Human Development (C.J.M.), and Synaptic Physiology Section, NINDS Intramural Research Program, National Institutes of Health, Bethesda, MD (J.S.D.); Department of Biochemistry and Molecular Biology, University of Texas Health Science Center, Houston, TX (V.J.); Department of Pharmacology, Department of Anaesthesia, Healthy Longevity Translational Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore (C.-M.L.); Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO (M.L.D.); and Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, GA (C.R.C., R.E.P., H.Y., S.F.T.)
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Gastrodin Attenuates Lipopolysaccharide-Induced Inflammatory Response and Migration via the Notch-1 Signaling Pathway in Activated Microglia. Neuromolecular Med 2021; 24:139-154. [PMID: 34109563 DOI: 10.1007/s12017-021-08671-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Accepted: 05/31/2021] [Indexed: 10/21/2022]
Abstract
Microglia-mediated neuroinflammation is known to play a pivotal role in the pathogenesis of different neurological diseases. Gastrodin, a phenolic glucoside, has been reported to exert anti-inflammatory effects in activated microglia challenged with lipopolysaccharide (LPS); however, the underlying mechanism has remained obscure. The present study aimed to ascertain if Gastrodin would regulate the Notch signaling pathway involved in microglia activation. We show here that LPS increased the expression of various members of the Notch-1 pathway, including intracellular Notch receptor domain (NICD), recombining binding protein suppressor of hairless (RBP-Jκ) and transcription factor hairy and enhancer of split-1 (Hes-1) in microglia in postnatal rat brain and in BV-2 microglia. Remarkably, Gastrodin was found to markedly attenuate the expression of the above various biomarkers both in vivo and in vitro. Moreover, increased phosphorylation level of ERK, JNK and P38 induced by LPS was attenuated with pretreatment of Notch-1 signaling inhibitor, N-[N-(3,5-difluorophenacetyl)-1-alany1-Sphenyglycinet-butylester (DAPT) as well as Gastrodin. Gastrodin mimicked the effects of DAPT by inhibiting the LPS-induced expression of IL-1β, IL-6, IL-23, TNF-α and NO. Moreover, lentivirus transfection mediated NICD overexpression inhibited the anti-inflammatory effects of Gastrodin. Furthermore, the activation of Notch-1 signaling promoted microglia migration and Gastrodin could inhibit the migration of activated BV-2 microglia by regulating the Notch-1 signaling pathway. In light of the above, our results indicate that Notch-1 signaling pathway is involved in the anti-inflammatory effects of Gastrodin against LPS-induced microglia activation. These findings provide a new biological target of Gastrodin for the treatment of neuroinflammatory disorders.
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Lipoxin A4 regulates microglial M1/M2 polarization after cerebral ischemia-reperfusion injury via the Notch signaling pathway. Exp Neurol 2021; 339:113645. [PMID: 33600815 DOI: 10.1016/j.expneurol.2021.113645] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2020] [Revised: 01/30/2021] [Accepted: 02/12/2021] [Indexed: 11/23/2022]
Abstract
Microglia are rapidly activated after acute ischemic stroke, and the polarization of microglial is associated with the prognosis of acute ischemic stroke. Lipoxin A4 (LXA4), an anti-inflammatory agent, has a protective effect against ischemic stroke. However, the role of LXA4 on the polarization of microglial after acute ischemic stroke remains undetermined. We hypothesized that LXA4 may exert the neuroprotective effect though regulating the polarization of microglial. In this study, clinical features of acute ischemic stroke were simulated using a rat model of model of middle cerebral artery occlusion (MCAO) in vivo and the BV2 microglia oxygen-glucose deprivation/reoxygenation model (OGD/R) in vitro. The protective effects of LXA4 on cerebral ischemia-reperfusion injury were determined using TTC staining, HE staining, and TUNEL staining. The expression of targeted genes was assayed using quantitative real-time PCR (qRT-PCR), immunofluorescence, and western blot to investigated the regulation of LXA4 on microglia polarization after acute ischemic stroke. We found that LXA4 exerted protective effects on focal cerebral ischemia-reperfusion injury and reduced the expression of the pro-inflammatory cytokines IL-1β and TNF-α. Furthermore, LXA4 inhibited the expression of Notch-1, Hes1, iNOS and CD32 all of which are associated with the differentiation into M1 microglia. By contrast, LXA4 upregulated the expression of Hes5, Arg-1 and CD206 all of which are associated with M2 phenotype in microglia. In addition, blocking the Notch signaling pathway with the inhibitor DAPT significantly mitigated the effect of LXA4 on microglia differentiation. These data suggest that LXA4 may regulate the polarization of microglia after cerebral ischemia-reperfusion injury through the Notch signaling pathway.
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Vaes JEG, Brandt MJV, Wanders N, Benders MJNL, de Theije CGM, Gressens P, Nijboer CH. The impact of trophic and immunomodulatory factors on oligodendrocyte maturation: Potential treatments for encephalopathy of prematurity. Glia 2020; 69:1311-1340. [PMID: 33595855 PMCID: PMC8246971 DOI: 10.1002/glia.23939] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2020] [Revised: 11/11/2020] [Accepted: 11/12/2020] [Indexed: 12/11/2022]
Abstract
Encephalopathy of prematurity (EoP) is a major cause of morbidity in preterm neonates, causing neurodevelopmental adversities that can lead to lifelong impairments. Preterm birth-related insults, such as cerebral oxygen fluctuations and perinatal inflammation, are believed to negatively impact brain development, leading to a range of brain abnormalities. Diffuse white matter injury is a major hallmark of EoP and characterized by widespread hypomyelination, the result of disturbances in oligodendrocyte lineage development. At present, there are no treatment options available, despite the enormous burden of EoP on patients, their families, and society. Over the years, research in the field of neonatal brain injury and other white matter pathologies has led to the identification of several promising trophic factors and cytokines that contribute to the survival and maturation of oligodendrocytes, and/or dampening neuroinflammation. In this review, we discuss the current literature on selected factors and their therapeutic potential to combat EoP, covering a wide range of in vitro, preclinical and clinical studies. Furthermore, we offer a future perspective on the translatability of these factors into clinical practice.
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Affiliation(s)
- Josine E G Vaes
- Department for Developmental Origins of Disease, University Medical Center Utrecht Brain Center and Wilhelmina Children's Hospital, Utrecht University, Utrecht, The Netherlands.,Department of Neonatology, University Medical Center Utrecht Brain Center and Wilhelmina Children's Hospital, Utrecht University, Utrecht, The Netherlands
| | - Myrna J V Brandt
- Department for Developmental Origins of Disease, University Medical Center Utrecht Brain Center and Wilhelmina Children's Hospital, Utrecht University, Utrecht, The Netherlands
| | - Nikki Wanders
- Department for Developmental Origins of Disease, University Medical Center Utrecht Brain Center and Wilhelmina Children's Hospital, Utrecht University, Utrecht, The Netherlands
| | - Manon J N L Benders
- Department of Neonatology, University Medical Center Utrecht Brain Center and Wilhelmina Children's Hospital, Utrecht University, Utrecht, The Netherlands
| | - Caroline G M de Theije
- Department for Developmental Origins of Disease, University Medical Center Utrecht Brain Center and Wilhelmina Children's Hospital, Utrecht University, Utrecht, The Netherlands
| | | | - Cora H Nijboer
- Department for Developmental Origins of Disease, University Medical Center Utrecht Brain Center and Wilhelmina Children's Hospital, Utrecht University, Utrecht, The Netherlands
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Kwak DG, Lee DG. Sequential Activation of AMPA Receptors and Glial Cells in a Pain Model of Lumbar Spine Disc Herniation. Ann Rehabil Med 2020; 44:343-352. [PMID: 32986944 PMCID: PMC7655227 DOI: 10.5535/arm.19202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Accepted: 03/11/2020] [Indexed: 12/01/2022] Open
Abstract
Objective To investigate the glial cell and AMPA (alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid) receptor activity after surgery for disc herniation pain model. Methods In total, 83 Sprague-Dawley rats were randomly assigned to the following groups: control (n=16), sham-operated (n=4), rats for pain behavior evaluation (n=3), nucleus pulposus-exposed groups for AMPA receptors (n=30), and glial cell (n=30). The rats were tested for mechanical allodynia; immunohistochemical staining for AMPA receptors (GluA1 and GluA2) and glial cells (OX-42 and glial fibrillary acid protein [GFAP]) in the spinal dorsal horn was performed on postoperative days 3, 7, and 14. Results Mechanical withdrawal thresholds decreased after surgery, and this effect was maintained for up to 14 days. Immunohistochemical expression of GluA1 and GluA2 in the spinal dorsal horn had increased quantitatively on postoperative days 3 and 7 (p<0.05) to levels similar to that of the controls on postoperative day 14. Moreover, immunohistochemical expression of OX-42 and GFAP showed similar changes to AMPA receptors after surgery. Although the activity of AMPA receptors and glial cells achieved normalcy, the mechanical withdrawal threshold of the hind paw remained decreased 38 days after surgery. Conclusion The rat model of lumbar disc herniation showed increased expression of AMPA receptor and glial cell activity in the spinal dorsal horn 3 and 7 days after surgery, which deceased to control levels at 14 days. The AMPA receptors and glial cell activations showed similar patterns after disc herniation surgery.
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Affiliation(s)
- Dong Gyu Kwak
- Department of Physical Medicine and Rehabilitation, Yeungnam University College of Medicine, Daegu, Korea
| | - Dong Gyu Lee
- Department of Physical Medicine and Rehabilitation, Yeungnam University College of Medicine, Daegu, Korea
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12
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Tang Z, Yang F, Dong Y, Ma C, Sun S, Shan Y, Zhang Y, Liu H. Midazolam contributes to neuroprotection against hypoxia/reoxygenation-induced brain injury in neonatal rats via regulation of EAAT2. Brain Res Bull 2020; 161:136-146. [DOI: 10.1016/j.brainresbull.2020.04.016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Revised: 03/18/2020] [Accepted: 04/20/2020] [Indexed: 01/22/2023]
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13
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Yuan Y, Wu C, Ling EA. Heterogeneity of Microglia Phenotypes: Developmental, Functional and Some Therapeutic Considerations. Curr Pharm Des 2020; 25:2375-2393. [PMID: 31584369 DOI: 10.2174/1381612825666190722114248] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Accepted: 07/12/2019] [Indexed: 02/06/2023]
Abstract
BACKGROUND Microglia play a pivotal role in maintaining homeostasis in complex brain environment. They first exist as amoeboid microglial cells (AMCs) in the developing brain, but with brain maturation, they transform into ramified microglial cells (RMCs). In pathological conditions, microglia are activated and have been classified into M1 and M2 phenotypes. The roles of AMCs, RMCs and M1/M2 microglia phenotypes especially in pathological conditions have been the focus of many recent studies. METHODS Here, we review the early development of the AMCs and RMCs and discuss their specific functions with reference to their anatomic locations, immunochemical coding etc. M1 and M2 microglia phenotypes in different neuropathological conditions are also reviewed. RESULTS Activated microglia are engaged in phagocytosis, production of proinflammatory mediators, trophic factors and synaptogenesis etc. Prolonged microglia activation, however, can cause damage to neurons and oligodendrocytes. The M1 and M2 phenotypes featured prominently in pathological conditions are discussed in depth. Experimental evidence suggests that microglia phenotype is being modulated by multiple factors including external and internal stimuli, local demands, epigenetic regulation, and herbal compounds. CONCLUSION Prevailing views converge that M2 polarization is neuroprotective. Thus, proper therapeutic designs including the use of anti-inflammatory drugs, herbal agents may be beneficial in suppression of microglial activation, especially M1 phenotype, for amelioration of neuroinflammation in different neuropathological conditions. Finally, recent development of radioligands targeting 18 kDa translocator protein (TSPO) in activated microglia may hold great promises clinically for early detection of brain lesion with the positron emission tomography.
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Affiliation(s)
- Yun Yuan
- Department of Anatomy and Histology/Embryology, Kunming Medical University, 1168 West Chunrong Road, Kunming, China
| | - Chunyun Wu
- Department of Anatomy and Histology/Embryology, Kunming Medical University, 1168 West Chunrong Road, Kunming, China
| | - Eng-Ang Ling
- Department of Anatomy, Yong Loo Lin School of Medicine, 4 Medical Drive, MD10, National University of Singapore, 117594, Singapore
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14
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Belov Kirdajova D, Kriska J, Tureckova J, Anderova M. Ischemia-Triggered Glutamate Excitotoxicity From the Perspective of Glial Cells. Front Cell Neurosci 2020; 14:51. [PMID: 32265656 PMCID: PMC7098326 DOI: 10.3389/fncel.2020.00051] [Citation(s) in RCA: 185] [Impact Index Per Article: 46.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Accepted: 02/21/2020] [Indexed: 12/21/2022] Open
Abstract
A plethora of neurological disorders shares a final common deadly pathway known as excitotoxicity. Among these disorders, ischemic injury is a prominent cause of death and disability worldwide. Brain ischemia stems from cardiac arrest or stroke, both responsible for insufficient blood supply to the brain parenchyma. Glucose and oxygen deficiency disrupts oxidative phosphorylation, which results in energy depletion and ionic imbalance, followed by cell membrane depolarization, calcium (Ca2+) overload, and extracellular accumulation of excitatory amino acid glutamate. If tight physiological regulation fails to clear the surplus of this neurotransmitter, subsequent prolonged activation of glutamate receptors forms a vicious circle between elevated concentrations of intracellular Ca2+ ions and aberrant glutamate release, aggravating the effect of this ischemic pathway. The activation of downstream Ca2+-dependent enzymes has a catastrophic impact on nervous tissue leading to cell death, accompanied by the formation of free radicals, edema, and inflammation. After decades of “neuron-centric” approaches, recent research has also finally shed some light on the role of glial cells in neurological diseases. It is becoming more and more evident that neurons and glia depend on each other. Neuronal cells, astrocytes, microglia, NG2 glia, and oligodendrocytes all have their roles in what is known as glutamate excitotoxicity. However, who is the main contributor to the ischemic pathway, and who is the unsuspecting victim? In this review article, we summarize the so-far-revealed roles of cells in the central nervous system, with particular attention to glial cells in ischemia-induced glutamate excitotoxicity, its origins, and consequences.
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Affiliation(s)
- Denisa Belov Kirdajova
- Department of Cellular Neurophysiology, Institute of Experimental Medicine, Academy of Sciences of the Czech Republic (ASCR), Prague, Czechia.,Second Faculty of Medicine, Charles University, Prague, Czechia
| | - Jan Kriska
- Department of Cellular Neurophysiology, Institute of Experimental Medicine, Academy of Sciences of the Czech Republic (ASCR), Prague, Czechia.,Second Faculty of Medicine, Charles University, Prague, Czechia
| | - Jana Tureckova
- Department of Cellular Neurophysiology, Institute of Experimental Medicine, Academy of Sciences of the Czech Republic (ASCR), Prague, Czechia
| | - Miroslava Anderova
- Department of Cellular Neurophysiology, Institute of Experimental Medicine, Academy of Sciences of the Czech Republic (ASCR), Prague, Czechia.,Second Faculty of Medicine, Charles University, Prague, Czechia
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15
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Chronic Exposure to High Altitude: Synaptic, Astroglial and Memory Changes. Sci Rep 2019; 9:16406. [PMID: 31712561 PMCID: PMC6848138 DOI: 10.1038/s41598-019-52563-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Accepted: 10/11/2019] [Indexed: 11/18/2022] Open
Abstract
Long-term operations carried out at high altitude (HA) by military personnel, pilots, and astronauts may trigger health complications. In particular, chronic exposure to high altitude (CEHA) has been associated with deficits in cognitive function. In this study, we found that mice exposed to chronic HA (5000 m for 12 weeks) exhibited deficits in learning and memory associated with hippocampal function and were linked with changes in the expression of synaptic proteins across various regions of the brain. Specifically, we found decreased levels of synaptophysin (SYP) (p < 0.05) and spinophilin (SPH) (p < 0.05) in the olfactory cortex, post synaptic density−95 (PSD-95) (p < 0.05), growth associated protein 43 (GAP43) (p < 0.05), glial fibrillary acidic protein (GFAP) (p < 0.05) in the cerebellum, and SYP (p < 0.05) and PSD-95 (p < 0.05) in the brainstem. Ultrastructural analyses of synaptic density and morphology in the hippocampus did not reveal any differences in CEHA mice compared to SL mice. Our data are novel and suggest that CEHA exposure leads to cognitive impairment in conjunction with neuroanatomically-based molecular changes in synaptic protein levels and astroglial cell marker in a region specific manner. We hypothesize that these new findings are part of highly complex molecular and neuroplasticity mechanisms underlying neuroadaptation response that occurs in brains when chronically exposed to HA.
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16
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Ceprian M, Fulton D. Glial Cell AMPA Receptors in Nervous System Health, Injury and Disease. Int J Mol Sci 2019; 20:E2450. [PMID: 31108947 PMCID: PMC6566241 DOI: 10.3390/ijms20102450] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Revised: 04/11/2019] [Accepted: 04/22/2019] [Indexed: 12/16/2022] Open
Abstract
Glia form a central component of the nervous system whose varied activities sustain an environment that is optimised for healthy development and neuronal function. Alpha-amino-3-hydroxy-5-methyl-4-isoxazole (AMPA)-type glutamate receptors (AMPAR) are a central mediator of glutamatergic excitatory synaptic transmission, yet they are also expressed in a wide range of glial cells where they influence a variety of important cellular functions. AMPAR enable glial cells to sense the activity of neighbouring axons and synapses, and as such many aspects of glial cell development and function are influenced by the activity of neural circuits. However, these AMPAR also render glia sensitive to elevations of the extracellular concentration of glutamate, which are associated with a broad range of pathological conditions. Excessive activation of AMPAR under these conditions may induce excitotoxic injury in glial cells, and trigger pathophysiological responses threatening other neural cells and amplifying ongoing disease processes. The aim of this review is to gather information on AMPAR function from across the broad diversity of glial cells, identify their contribution to pathophysiological processes, and highlight new areas of research whose progress may increase our understanding of nervous system dysfunction and disease.
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Affiliation(s)
- Maria Ceprian
- Instituto de Investigación Sanitaria San Carlos (IdISSC), 28040 Madrid, Spain.
- Departamento de Bioquímica y Biología Molecular, CIBERNED, IRICYS. Facultad de Medicina, Universidad Complutense de Madrid, 28040 Madrid, Spain.
| | - Daniel Fulton
- Neuroscience and Ophthalmology Research Group, Institute of Inflammation and Ageing, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK.
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17
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Osipova ED, Semyachkina-Glushkovskaya OV, Morgun AV, Pisareva NV, Malinovskaya NA, Boitsova EB, Pozhilenkova EA, Belova OA, Salmin VV, Taranushenko TE, Noda M, Salmina AB. Gliotransmitters and cytokines in the control of blood-brain barrier permeability. Rev Neurosci 2018; 29:567-591. [DOI: 10.1515/revneuro-2017-0092] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Accepted: 11/26/2017] [Indexed: 11/15/2022]
Abstract
AbstractThe contribution of astrocytes and microglia to the regulation of neuroplasticity or neurovascular unit (NVU) is based on the coordinated secretion of gliotransmitters and cytokines and the release and uptake of metabolites. Blood-brain barrier (BBB) integrity and angiogenesis are influenced by perivascular cells contacting with the abluminal side of brain microvessel endothelial cells (pericytes, astrocytes) or by immune cells existing (microglia) or invading the NVU (macrophages) under pathologic conditions. The release of gliotransmitters or cytokines by activated astroglial and microglial cells is provided by distinct mechanisms, affects intercellular communication, and results in the establishment of microenvironment controlling BBB permeability and neuroinflammation. Glial glutamate transporters and connexin and pannexin hemichannels working in the tight functional coupling with the purinergic system serve as promising molecular targets for manipulating the intercellular communications that control BBB permeability in brain pathologies associated with excessive angiogenesis, cerebrovascular remodeling, and BBB-mediated neuroinflammation. Substantial progress in deciphering the molecular mechanisms underlying the (patho)physiology of perivascular glia provides promising approaches to novel clinically relevant therapies for brain disorders. The present review summarizes the current understandings on the secretory machinery expressed in glial cells (glutamate transporters, connexin and pannexin hemichannels, exocytosis mechanisms, membrane-derived microvesicles, and inflammasomes) and the role of secreted gliotransmitters and cytokines in the regulation of NVU and BBB permeability in (patho)physiologic conditions.
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18
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Singh DK, Ling EA, Kaur C. Hypoxia and myelination deficits in the developing brain. Int J Dev Neurosci 2018; 70:3-11. [PMID: 29964158 DOI: 10.1016/j.ijdevneu.2018.06.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Revised: 05/28/2018] [Accepted: 06/26/2018] [Indexed: 12/15/2022] Open
Abstract
Myelination is a complex and orderly process during brain development that is essential for normal motor, cognitive and sensory functions. Cellular and molecular interactions between myelin-forming oligodendrocytes and axons are required for normal myelination in the developing brain. Oligodendrocyte progenitor cells (OPCs) proliferate and differentiate into mature myelin-forming oligodendrocytes. In this connection, astrocytes and microglia are also involved in survival and proliferation of OPCs. Hypoxic insults during the perinatal period affect the normal development, differentiation and maturation of the OPCs or cause their death resulting in impaired myelination. Several factors such as augmented release of proinflammatory cytokines by activated microglia and astrocytes, extracellular accumulation of excess glutamate and increased levels of nitric oxide are some of the underlying factors for hypoxia induced damage to the OPCs. Additionally, hypoxia also leads to down-regulation of several genes involved in oligodendrocyte differentiation encoding proteolipid protein, platelet-derived growth factor receptor and myelin-associated glycoprotein in the developing brain. Furthermore, oligodendrocytes may also accumulate increased amounts of iron in hypoxic conditions that triggers endoplasmic reticulum stress, misfolding of proteins and generation of reactive oxygen species that ultimately would lead to myelination deficits. More in-depth studies to elucidate the pathophysiological mechanisms underlying the inability of oligodendrocytes to myelinate the developing brain in hypoxic insults are desirable to develop new therapeutic options or strategies for myelination deficits.
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Affiliation(s)
- Dhiraj Kumar Singh
- Department of Anatomy, Yong Loo Lin School of Medicine, MD10, 4 Medical drive, National University of Singapore, 117597, Singapore
| | - Eng-Ang Ling
- Department of Anatomy, Yong Loo Lin School of Medicine, MD10, 4 Medical drive, National University of Singapore, 117597, Singapore
| | - Charanjit Kaur
- Department of Anatomy, Yong Loo Lin School of Medicine, MD10, 4 Medical drive, National University of Singapore, 117597, Singapore.
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19
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Begum G, Otsu M, Ahmed U, Ahmed Z, Stevens A, Fulton D. NF-Y-dependent regulation of glutamate receptor 4 expression and cell survival in cells of the oligodendrocyte lineage. Glia 2018; 66:1896-1914. [PMID: 29704264 PMCID: PMC6220837 DOI: 10.1002/glia.23446] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Revised: 03/14/2018] [Accepted: 04/11/2018] [Indexed: 12/15/2022]
Abstract
Glutamate receptor subunit 4 (GluA4) is highly expressed by neural cells sensitive to excitotoxicity, and is the predominant subunit expressed by oligodendrocyte precursor cells (OPC) during a key period of vulnerability to hypoxic‐ischemic injury. Therefore, transcriptional networks downstream of excitotoxic GluA4 activation represent a promising area for therapeutic intervention. In this work, we identify the CCAAT binding transcription factor NF‐Yb as a novel transcriptional regulator of Gria4 (GluA4 gene), and a controller of excitotoxic death in the oligodendroglial lineage. We describe a novel regulatory region within Gria4 containing CCAAT sequences whose binding by NF‐Yb is regulated by excitotoxicity. Excitotoxicity‐induced alterations in NF‐Yb binding are associated with changes in Gria4 transcription, while knockdown of NF‐Yb alters the transcription of reporter constructs containing this regulatory region. Data from immortalized and primary OPC reveal that RNAi and pharmacological disruption of NF‐Yb alter Gria4 transcription, with the latter inducing apoptosis and influencing a set of apoptotic genes similarly regulated during excitotoxicity. These data provide the first definition of a trans‐acting mechanism regulating Gria4, and identify the NF‐Y network as a potential source of pharmacological targets for promoting OPC survival.
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Affiliation(s)
- Ghazala Begum
- Neuroscience and Ophthalmology Research Group, Institute of Inflammation and Ageing, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom
| | - Masahiro Otsu
- Neuroscience and Ophthalmology Research Group, Institute of Inflammation and Ageing, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom
| | - Usman Ahmed
- Neuroscience and Ophthalmology Research Group, Institute of Inflammation and Ageing, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom
| | - Zubair Ahmed
- Neuroscience and Ophthalmology Research Group, Institute of Inflammation and Ageing, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom
| | - Adam Stevens
- Division of Developmental Biology & Medicine, Faculty of Biology, Medicine & Health, University of Manchester, Manchester Academic Health Sciences Centre, Manchester M13 9PL, United Kingdom
| | - Daniel Fulton
- Neuroscience and Ophthalmology Research Group, Institute of Inflammation and Ageing, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom
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20
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Zhu H, Wang DD, Yuan T, Yan FJ, Zeng CM, Dai XY, Chen ZB, Chen Y, Zhou T, Fan GH, Ying M, Cao J, Luo P, Liu XJ, Hu Y, Peng Y, He Q, Yang B. Multikinase Inhibitor CT-707 Targets Liver Cancer by Interrupting the Hypoxia-Activated IGF-1R-YAP Axis. Cancer Res 2018; 78:3995-4006. [PMID: 29669759 DOI: 10.1158/0008-5472.can-17-1548] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Revised: 01/22/2018] [Accepted: 04/12/2018] [Indexed: 11/16/2022]
Abstract
Given that Yes-associated protein (YAP) signaling acts as a critical survival input for hypoxic cancer cells in hepatocellular carcinoma (HCC), disruption of YAP function and the maintenance of hypoxia is an attractive way to treat HCC. Utilizing a cell-based YAP-TEAD luciferase reporter assay and functional analyses, we identified CT-707, a China-FDA approved multi-kinase inhibitor under clinical trial with remarkable inhibitory activity against YAP function. CT-707 exhibited prominent cytotoxicity under hypoxia on HCC cells, which was attributable to the inhibition of YAP signaling. CT-707 arrested tumor growth in HepG2, Bel-7402, and HCC patient-derived xenografts. Mechanistically, the inhibitory activity of CT-707 on YAP signaling was due to the interruption of hypoxia-activated IGF1R. Overall, these findings not only identify CT-707 as a promising hypoxia-targeting agent against HCC, but they also unveil IGF1R as a new modulator specifically regulating hypoxia-activated YAP signaling.Significance: CT-707 may represent a novel clinical approach for patients with HCC suffering poor drug response due to intratumor hypoxia. Cancer Res; 78(14); 3995-4006. ©2018 AACR.
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Affiliation(s)
- Hong Zhu
- Zhejiang Province Key Laboratory of Anti-Cancer Drug Research, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, China
| | - Dan-Dan Wang
- Zhejiang Province Key Laboratory of Anti-Cancer Drug Research, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, China
| | - Tao Yuan
- Zhejiang Province Key Laboratory of Anti-Cancer Drug Research, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, China
| | - Fang-Jie Yan
- Zhejiang Province Key Laboratory of Anti-Cancer Drug Research, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, China
| | - Chen-Ming Zeng
- Zhejiang Province Key Laboratory of Anti-Cancer Drug Research, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, China
| | - Xiao-Yang Dai
- Center for Drug Safety Evaluation and Research of Zhejiang University, Hangzhou, China
| | - Zi-Bo Chen
- Zhejiang Province Key Laboratory of Anti-Cancer Drug Research, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, China
| | - Ying Chen
- Zhejiang Province Key Laboratory of Anti-Cancer Drug Research, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, China
| | - Tianyi Zhou
- Zhejiang Province Key Laboratory of Anti-Cancer Drug Research, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, China
| | - Guang-Han Fan
- Zhejiang Province Key Laboratory of Anti-Cancer Drug Research, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, China
| | - Meidan Ying
- Zhejiang Province Key Laboratory of Anti-Cancer Drug Research, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, China
| | - Ji Cao
- Zhejiang Province Key Laboratory of Anti-Cancer Drug Research, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, China
| | - Peihua Luo
- Zhejiang Province Key Laboratory of Anti-Cancer Drug Research, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, China
| | - Xi-Jie Liu
- Medicinal Chemistry Department, Centaurus BioPharma Co., Ltd., Beijing, China
| | - Yuandong Hu
- Medicinal Chemistry Department, Centaurus BioPharma Co., Ltd., Beijing, China
| | - Yong Peng
- Discovery Biology Department, Centaurus BioPharma Co., Ltd., Beijing, China
| | - Qiaojun He
- Zhejiang Province Key Laboratory of Anti-Cancer Drug Research, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, China.
| | - Bo Yang
- Zhejiang Province Key Laboratory of Anti-Cancer Drug Research, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, China.
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21
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Socodato R, Portugal CC, Rodrigues A, Henriques J, Rodrigues C, Figueira C, Relvas JB. Redox tuning of Ca 2+ signaling in microglia drives glutamate release during hypoxia. Free Radic Biol Med 2018; 118:137-149. [PMID: 29501565 DOI: 10.1016/j.freeradbiomed.2018.02.036] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Revised: 01/31/2018] [Accepted: 02/27/2018] [Indexed: 02/07/2023]
Abstract
Hypoxia causes oxidative stress and excitotoxicity, culminating in neuronal damage during brain ischemia. Hypoxia also activates microglia, the myeloid resident cells of the brain parenchyma. Upon activation, microglia release high amounts of the neurotransmitter glutamate, contributing for neuronal excitotoxicity during brain insults. Here, we reveal a signaling pathway controlling glutamate release from human microglia during hypoxia. We show that hypoxia-mediated redox imbalance promotes the activation of endoplasmic reticulum inositol 1,4,5-trisphosphate (InsP3) receptors leading to Ca2+ mobilization into the cytosol. Increasing cytosolic Ca2+ signaling in microglia activates the non-receptor protein tyrosine kinase Src at the plasma membrane. Src activation enhances the permeability of microglial gap junctions promoting the release of glutamate during hypoxia. Preventing the hypoxia-triggered redox imbalance, using the dietary antioxidants neochlorogenic acid or vitamin C, inhibits InsP3-dependent Ca2+ signaling and abrogates the release of glutamate. Overall, modulating microglial Ca2+ signaling in response to changes in the redox microenvironment might be critical for controlling glutamate excitotoxicity during hypoxia.
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Affiliation(s)
- Renato Socodato
- Instituto de Investigação e Inovação em Saúde and Instituto de Biologia Molecular e Celular (IBMC) and The Discoveries Centre for Regeneration and Precision Medicine - Porto campus, Universidade do Porto, Porto, Portugal.
| | - Camila C Portugal
- Instituto de Investigação e Inovação em Saúde and Instituto de Biologia Molecular e Celular (IBMC) and The Discoveries Centre for Regeneration and Precision Medicine - Porto campus, Universidade do Porto, Porto, Portugal
| | - Artur Rodrigues
- Instituto de Investigação e Inovação em Saúde and Instituto de Biologia Molecular e Celular (IBMC) and The Discoveries Centre for Regeneration and Precision Medicine - Porto campus, Universidade do Porto, Porto, Portugal
| | - Joana Henriques
- Instituto de Investigação e Inovação em Saúde and Instituto de Biologia Molecular e Celular (IBMC) and The Discoveries Centre for Regeneration and Precision Medicine - Porto campus, Universidade do Porto, Porto, Portugal
| | - Carla Rodrigues
- Diverge, Grupo Nabeiro Innovation Center, Alameda dos Oceanos 65, 1.1, 1900-208 Lisbon, Portugal
| | - Cláudia Figueira
- Diverge, Grupo Nabeiro Innovation Center, Alameda dos Oceanos 65, 1.1, 1900-208 Lisbon, Portugal
| | - João B Relvas
- Instituto de Investigação e Inovação em Saúde and Instituto de Biologia Molecular e Celular (IBMC) and The Discoveries Centre for Regeneration and Precision Medicine - Porto campus, Universidade do Porto, Porto, Portugal.
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22
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Mohandas N, Bass-Stringer S, Maksimovic J, Crompton K, Loke YJ, Walstab J, Reid SM, Amor DJ, Reddihough D, Craig JM. Epigenome-wide analysis in newborn blood spots from monozygotic twins discordant for cerebral palsy reveals consistent regional differences in DNA methylation. Clin Epigenetics 2018; 10:25. [PMID: 29484035 PMCID: PMC5824607 DOI: 10.1186/s13148-018-0457-4] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Accepted: 02/12/2018] [Indexed: 12/21/2022] Open
Abstract
Background Cerebral palsy (CP) is a clinical description for a group of motor disorders that are heterogeneous with respect to causes, symptoms and severity. A diagnosis of CP cannot usually be made at birth and in some cases may be delayed until 2–3 years of age. This limits opportunities for early intervention that could otherwise improve long-term outcomes. CP has been recorded in monozygotic twins discordant for the disorder, indicating a potential role of non-genetic factors such as intrauterine infection, hypoxia-ischaemia, haemorrhage and thrombosis. The aim of this exploratory study was to utilise the discordant monozygotic twin model to understand and measure epigenetic changes associated with the development of CP. Methods We performed a genome-wide analysis of DNA methylation using the Illumina Infinium Human Methylation 450 BeadChip array with DNA from newborn blood spots of 15 monozygotic twin pairs who later became discordant for CP. Quality control and data preprocessing were undertaken using the minfi R package. Differential methylation analysis was performed using the remove unwanted variation (RUVm) method, taking twin pairing into account in order to identify CP-specific differentially methylated probes (DMPs), and bumphunter was performed to identify differentially methylated regions (DMRs). Results We identified 33 top-ranked DMPs based on a nominal p value cut-off of p < 1 × 10−4 and two DMRs (p < 1 × 10−3) associated with CP. The top-ranked probes related to 25 genes including HNRNPL, RASSF5, CD3D and KALRN involved in immune signalling pathways, in addition to TBC1D24, FBXO9 and VIPR2 previously linked to epileptic encephalopathy. Gene ontology and pathway analysis of top-ranked DMP-associated genes revealed enrichment of inflammatory signalling pathways, regulation of cytokine secretion and regulation of leukocyte-mediated immunity. We also identified two top-ranked DMRs including one on chromosome 6 within the promoter region of LTA gene encoding tumour necrosis factor-beta (TNF-β), an important regulator of inflammation and brain development. The second was within the transcription start site of the LIME1 gene, which plays a key role in inflammatory pathways such as MAPK signalling. CP-specific differential DNA methylation within one of our two top DMRs was validated using an independent platform, MassArray EpiTyper. Conclusions Ours is the first epigenome-wide association study of CP in disease-discordant monozygotic twin pairs and suggests a potential role for immune dysfunction in this condition. Electronic supplementary material The online version of this article (10.1186/s13148-018-0457-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Namitha Mohandas
- Environmental and Genetic Epidemiology Research, Murdoch Children's Research Institute, Royal Children's Hospital, Flemington Road, Parkville, Victoria 3052 Australia.,2Department of Paediatrics, The University of Melbourne, Flemington Road, Parkville, Victoria 3052 Australia
| | - Sebastian Bass-Stringer
- Environmental and Genetic Epidemiology Research, Murdoch Children's Research Institute, Royal Children's Hospital, Flemington Road, Parkville, Victoria 3052 Australia
| | - Jovana Maksimovic
- 2Department of Paediatrics, The University of Melbourne, Flemington Road, Parkville, Victoria 3052 Australia.,Bioinformatics Group, Murdoch Children's Research Institute, Royal Children's Hospital, Flemington Road, Parkville, Victoria 3052 Australia
| | - Kylie Crompton
- 2Department of Paediatrics, The University of Melbourne, Flemington Road, Parkville, Victoria 3052 Australia.,4Developmental Disability and Rehabilitation Research, Murdoch Children's Research Institute, Flemington Road, Parkville, Victoria 3052 Australia.,5Neurodevelopment and Disability, The Royal Children's Hospital, Flemington Road, Parkville, Victoria 3052 Australia
| | - Yuk J Loke
- Environmental and Genetic Epidemiology Research, Murdoch Children's Research Institute, Royal Children's Hospital, Flemington Road, Parkville, Victoria 3052 Australia
| | - Janet Walstab
- 2Department of Paediatrics, The University of Melbourne, Flemington Road, Parkville, Victoria 3052 Australia.,4Developmental Disability and Rehabilitation Research, Murdoch Children's Research Institute, Flemington Road, Parkville, Victoria 3052 Australia
| | - Susan M Reid
- 2Department of Paediatrics, The University of Melbourne, Flemington Road, Parkville, Victoria 3052 Australia.,4Developmental Disability and Rehabilitation Research, Murdoch Children's Research Institute, Flemington Road, Parkville, Victoria 3052 Australia.,5Neurodevelopment and Disability, The Royal Children's Hospital, Flemington Road, Parkville, Victoria 3052 Australia
| | - David J Amor
- 2Department of Paediatrics, The University of Melbourne, Flemington Road, Parkville, Victoria 3052 Australia.,4Developmental Disability and Rehabilitation Research, Murdoch Children's Research Institute, Flemington Road, Parkville, Victoria 3052 Australia.,5Neurodevelopment and Disability, The Royal Children's Hospital, Flemington Road, Parkville, Victoria 3052 Australia
| | - Dinah Reddihough
- 2Department of Paediatrics, The University of Melbourne, Flemington Road, Parkville, Victoria 3052 Australia.,4Developmental Disability and Rehabilitation Research, Murdoch Children's Research Institute, Flemington Road, Parkville, Victoria 3052 Australia.,5Neurodevelopment and Disability, The Royal Children's Hospital, Flemington Road, Parkville, Victoria 3052 Australia
| | - Jeffrey M Craig
- Environmental and Genetic Epidemiology Research, Murdoch Children's Research Institute, Royal Children's Hospital, Flemington Road, Parkville, Victoria 3052 Australia.,2Department of Paediatrics, The University of Melbourne, Flemington Road, Parkville, Victoria 3052 Australia.,6Centre for Molecular and Medical Research, School of Medicine, Deakin University, Geelong, Victoria 3220 Australia
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Kaur C, Rathnasamy G, Ling EA. Biology of Microglia in the Developing Brain. J Neuropathol Exp Neurol 2017; 76:736-753. [PMID: 28859332 DOI: 10.1093/jnen/nlx056] [Citation(s) in RCA: 82] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Microglia exist in different morphological forms in the developing brain. They show a small cell body with scanty cytoplasm with many branching processes in the grey matter of the developing brain. However, in the white matter such as the corpus callosum where the unmyelinated axons are loosely organized, they appear in an amoeboid form having a round cell body endowed with copious cytoplasm rich in organelles. The amoeboid cells eventually transform into ramified microglia in the second postnatal week when the tissue becomes more compact with the onset of myelination. Microglia serve as immunocompetent macrophages that act as neuropathology sensors to detect and respond swiftly to subtle changes in the brain tissues in pathological conditions. Microglial functions are broadly considered as protective in the normal brain development as they phagocytose dead cells and sculpt neuronal connections by pruning excess axons and synapses. They also secrete a number of trophic factors such as insulin-like growth factor-1 and transforming growth factor-β among many others that are involved in neuronal and oligodendrocyte survival. On the other hand, microglial cells when activated produce a plethora of molecules such as proinflammatory cytokines, chemokines, reactive oxygen species, and nitric oxide that are implicated in the pathogenesis of many pathological conditions such as epilepsy, cerebral palsy, autism, and perinatal hypoxic-ischemic brain injury. Although many studies have investigated the origin and functions of the microglia in the developing brain, in-depth in vivo studies along with analysis of their transcriptome and epigenetic changes need to be undertaken to elucidate their full potential be it protective or neurotoxic. This would lead to a better understanding of their roles in the healthy and diseased developing brain and advancement of therapeutic strategies to target microglia-mediated neurotoxicity.
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Affiliation(s)
- Charanjit Kaur
- Department of Anatomy, Yong Loo Lin School of Medicine, National University of Singapore, Singapore; and Department of Ophthalmology and Visual Sciences, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin
| | - Gurugirijha Rathnasamy
- Department of Anatomy, Yong Loo Lin School of Medicine, National University of Singapore, Singapore; and Department of Ophthalmology and Visual Sciences, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin
| | - Eng-Ang Ling
- Department of Anatomy, Yong Loo Lin School of Medicine, National University of Singapore, Singapore; and Department of Ophthalmology and Visual Sciences, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin
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Tolcos M, Petratos S, Hirst JJ, Wong F, Spencer SJ, Azhan A, Emery B, Walker DW. Blocked, delayed, or obstructed: What causes poor white matter development in intrauterine growth restricted infants? Prog Neurobiol 2017; 154:62-77. [PMID: 28392287 DOI: 10.1016/j.pneurobio.2017.03.009] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Revised: 03/17/2017] [Accepted: 03/29/2017] [Indexed: 12/22/2022]
Abstract
Poor white matter development in intrauterine growth restricted (IUGR) babies remains a major, untreated problem in neonatology. New therapies, guided by an understanding of the mechanisms that underlie normal and abnormal oligodendrocyte development and myelin formation, are required. Much of our knowledge of the mechanisms that underlie impaired myelination come from studies in adult demyelinating disease, preterm brain injury, or experimental models of hypoxia-ischemia. However, relatively less is known for IUGR which is surprising because IUGR is a leading cause of perinatal mortality and morbidity, second only to premature birth. IUGR is also a significant risk factor for the later development of cerebral palsy, and is a greater risk compared to some of the more traditionally researched antecedents - asphyxia and inflammation. Recent evidence suggests that the white matter injury and reduced myelination in the brains of some preterm babies is due to impaired maturation of oligodendrocytes thereby resulting in the reduced capacity to synthesize myelin. Therefore, it is not surprising that the hypomyelination observable in the central nervous system of IUGR infants has similarly lead to investigations identifying a delay or blockade in the progress of maturation of oligodendrocytes in these infants. This review will discuss current ideas thought to account for the poor myelination often present in the neonate's brain following IUGR, and discuss novel interventions that are promising as treatments that promote oligodendrocyte maturation, and thereby repair the myelination deficits that otherwise persist into infancy and childhood and lead to neurodevelopmental abnormalities.
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Affiliation(s)
- Mary Tolcos
- School of Health and Biomedical Sciences, RMIT University, Bundoora, Victoria, 3083, Australia.
| | - Steven Petratos
- Department of Medicine, Central Clinical School, Monash University, Prahran, Victoria, 3004, Australia
| | - Jonathan J Hirst
- School of Biomedical Sciences, University of Newcastle, Callaghan, NSW, 2308, Australia
| | - Flora Wong
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, Victoria, 3168, Australia; Monash Newborn and Monash University, Clayton, Victoria, 3168, Australia
| | - Sarah J Spencer
- School of Health and Biomedical Sciences, RMIT University, Bundoora, Victoria, 3083, Australia
| | - Aminath Azhan
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, Victoria, 3168, Australia
| | - Ben Emery
- Oregon Health and Science University, Portland, OR, 97239-3098, USA
| | - David W Walker
- School of Health and Biomedical Sciences, RMIT University, Bundoora, Victoria, 3083, Australia
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25
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Shukla M, Govitrapong P, Boontem P, Reiter RJ, Satayavivad J. Mechanisms of Melatonin in Alleviating Alzheimer's Disease. Curr Neuropharmacol 2017; 15:1010-1031. [PMID: 28294066 PMCID: PMC5652010 DOI: 10.2174/1570159x15666170313123454] [Citation(s) in RCA: 116] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Revised: 02/10/2017] [Accepted: 03/09/2017] [Indexed: 02/07/2023] Open
Abstract
Alzheimer's disease (AD) is a chronic, progressive and prevalent neurodegenerative disease characterized by the loss of higher cognitive functions and an associated loss of memory. The thus far "incurable" stigma for AD prevails because of variations in the success rates of different treatment protocols in animal and human studies. Among the classical hypotheses explaining AD pathogenesis, the amyloid hypothesis is currently being targeted for drug development. The underlying concept is to prevent the formation of these neurotoxic peptides which play a central role in AD pathology and trigger a multispectral cascade of neurodegenerative processes post-aggregation. This could possibly be achieved by pharmacological inhibition of β- or γ-secretase or stimulating the nonamyloidogenic α-secretase. Melatonin the pineal hormone is a multifunctioning indoleamine. Production of this amphiphilic molecule diminishes with advancing age and this decrease runs parallel with the progression of AD which itself explains the potential benefits of melatonin in line of development and devastating consequences of the disease progression. Our recent studies have revealed a novel mechanism by which melatonin stimulates the nonamyloidogenic processing and inhibits the amyloidogenic processing of β-amyloid precursor protein (βAPP) by stimulating α -secretases and consequently down regulating both β- and γ-secretases at the transcriptional level. In this review, we discuss and evaluate the neuroprotective functions of melatonin in AD pathogenesis, including its role in the classical hypotheses in cellular and animal models and clinical interventions in AD patients, and suggest that with early detection, melatonin treatment is qualified to be an anti-AD therapy.
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Affiliation(s)
- Mayuri Shukla
- Chulabhorn Graduate Institute, Chulabhorn Royal Academy, 54 Kamphaeng Phet 6 Road, Lak Si, Bangkok10210, Thailand
| | - Piyarat Govitrapong
- Chulabhorn Graduate Institute, Chulabhorn Royal Academy, 54 Kamphaeng Phet 6 Road, Lak Si, Bangkok10210, Thailand
- Research Center for Neuroscience, Institute of Molecular Biosciences, Mahidol University, Salaya, Nakornpathom 73170, Thailand
| | - Parichart Boontem
- Chulabhorn Graduate Institute, Chulabhorn Royal Academy, 54 Kamphaeng Phet 6 Road, Lak Si, Bangkok10210, Thailand
| | - Russel J. Reiter
- Department of Cellular and Structural Biology, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA
| | - Jutamaad Satayavivad
- Chulabhorn Research Institute and Chulabhorn Graduate Institute, Chulabhorn Royal Academy, Bangkok10210, Thailand
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26
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Liu H, Leak RK, Hu X. Neurotransmitter receptors on microglia. Stroke Vasc Neurol 2016; 1:52-58. [PMID: 28959464 PMCID: PMC5435193 DOI: 10.1136/svn-2016-000012] [Citation(s) in RCA: 106] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2016] [Revised: 04/29/2016] [Accepted: 04/30/2016] [Indexed: 12/21/2022] Open
Abstract
As the resident immune cells in the central nervous system, microglia have long been hypothesised to promote neuroinflammation and exacerbate neurotoxicity. However, this traditional view has undergone recent revision as evidence has accumulated that microglia exert beneficial and detrimental effects depending on activation status, polarisation phenotype and cellular context. A variety of neurotransmitter receptors are expressed on microglia and help mediate the bidirectional communication between neurons and microglia. Here we review data supporting the importance of neurotransmitter receptors on microglia, with a special emphasis on glutamate, γ-aminobutyric acid (GABA), norepinephrine, cannabinoid and acetylcholine receptors. We summarise evidence favouring a significant role for neurotransmitter receptors in modulating microglial activation, phagocytic clearance and phenotypic polarisation. Elucidating the effects of neurotransmitter receptors on microglia and dissecting the underlying mechanisms may help accelerate the discovery of novel drugs that tap the therapeutic potential of microglia.
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Affiliation(s)
- Huan Liu
- Center of Cerebrovascular Disease Research, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Rehana K Leak
- Division of Pharmaceutical Sciences, Duquesne University, Pittsburgh, Pennsylvania, USA
| | - Xiaoming Hu
- Center of Cerebrovascular Disease Research, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
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Xiao J, Huang Y, Li X, Li L, Yang T, Huang L, Yang L, Jiang H, Li H, Li F. TNP-ATP is Beneficial for Treatment of Neonatal Hypoxia-Induced Hypomyelination and Cognitive Decline. Neurosci Bull 2016; 32:99-107. [PMID: 26769489 DOI: 10.1007/s12264-015-0003-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Accepted: 11/17/2015] [Indexed: 12/15/2022] Open
Abstract
Our previous study together with other investigations have reported that neonatal hypoxia or ischemia induces long-term cognitive impairment, at least in part through brain inflammation and hypomyelination. However, the detailed mechanisms are not fully understood. Here, we used a rodent model of neonatal hypoxia by subjecting postnatal day 0 (P0) rat pups to systemic hypoxia (3.5 h). We found that neonatal hypoxia increased the glutamate content and initiated inflammatory responses at 4 h and 1 day after hypoxia, caused hypomyelination in the corpus callosum, and impaired hippocampus-dependent learning and memory when assessed 30-60 days after hypoxia. Interestingly, much of the hypoxia-induced brain damage was ameliorated by treatment with the ATP analogue 2',3'-0-(2,4,6-trinitrophenyl)-adenosine 5'-triphosphate (TNP-ATP; blocks all ionotropic P2X1-7 receptors), whereas treatment with pyridoxalphosphate-6-azophenyl-2',4'-disulphonic acid (PPADS; inhibits P2X1-3 and P2X5-7 receptors) was less neuroprotective. Our data indicated that activation of ionotropic ATP receptors might be partially, if not fully, involved in glutamate deregulation, neuroinflammation, hypomyelination, and cognitive dysfunction after neonatal hypoxia.
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Affiliation(s)
- Jie Xiao
- Department of Pathology and Pathophysiology, School of Basic Medical Science, Kunming Medical University, Kunming, 650500, China
| | - Yilong Huang
- Department of Pathology and Pathophysiology, School of Basic Medical Science, Kunming Medical University, Kunming, 650500, China
| | - Xia Li
- Department of Pathology and Pathophysiology, School of Basic Medical Science, Kunming Medical University, Kunming, 650500, China
| | - Longjun Li
- Department of Pathology and Pathophysiology, School of Basic Medical Science, Kunming Medical University, Kunming, 650500, China
| | - Ting Yang
- Department of Pathology and Pathophysiology, School of Basic Medical Science, Kunming Medical University, Kunming, 650500, China
| | - Lixuan Huang
- Department of Pathology and Pathophysiology, School of Basic Medical Science, Kunming Medical University, Kunming, 650500, China
| | - Ling Yang
- Department of Pathology and Pathophysiology, School of Basic Medical Science, Kunming Medical University, Kunming, 650500, China
| | - Hong Jiang
- Department of Pathology and Pathophysiology, School of Basic Medical Science, Kunming Medical University, Kunming, 650500, China
| | - Hongchun Li
- Department of Pathology and Pathophysiology, School of Basic Medical Science, Kunming Medical University, Kunming, 650500, China
| | - Fan Li
- Department of Pathology and Pathophysiology, School of Basic Medical Science, Kunming Medical University, Kunming, 650500, China.
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28
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Yuan Y, Rangarajan P, Kan EM, Wu Y, Wu C, Ling EA. Scutellarin regulates the Notch pathway and affects the migration and morphological transformation of activated microglia in experimentally induced cerebral ischemia in rats and in activated BV-2 microglia. J Neuroinflammation 2015; 12:11. [PMID: 25600517 PMCID: PMC4316603 DOI: 10.1186/s12974-014-0226-z] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Accepted: 12/19/2014] [Indexed: 01/06/2023] Open
Abstract
Background Activated microglial cells release an excess of inflammatory mediators after an ischemic stroke. We reported previously that scutellarin effectively suppressed the inflammatory response induced by activated microglia in rats subjected to middle cerebral artery occlusion (MCAO); however, the mechanism via which scutellarin exerts its effects on microglial activation has not been explored. This study aimed to elucidate if scutellarin can regulate the Notch pathway that is linked to microglia activation in MCAO rat, and in lipopolysaccharide (LPS)-induced BV-2 microglia. Along with this, we also investigated some characteristic behavioral responses of activated microglia. Methods Expression of various members of the Notch pathway, including Notch-1, intracellular Notch receptor domain (NICD), recombining binding protein suppressor of hairless (RBP-JK) and transcription factor hairy and enhancer of split-1 (Hes-1) in activated microglia was assessed by immunofluorescence staining and western blot after experimental MCAO and in vitro LPS activation. The effect of scutellarin on migration of microglia was determined by the transwell chamber assay as well as expression of monocyte chemoattractant protein-1 (MCP-1). The morphological change of microglia induced by scutellarin was detected by F-actin staining and electron microscopy. Results Scutellarin markedly attenuated the expression of NF-κB, Notch-1, NICD, RBP-JK and Hes-1 both in vivo and in activated microglia. It decreased the expression of MCP-1 and microglial migration, but increased the ability of microglia adhesion. Scutellarin also altered the phenotype of microglia by causing rearrangement or reorganization of its cytoskeleton. Conclusions The results suggest that scutellarin regulates the activation of microglia via the Notch pathway and concurrently induces morphological and functional changes in activated microglia. Electronic supplementary material The online version of this article (doi:10.1186/s12974-014-0226-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Yun Yuan
- Department of Anatomy and Histology/Embryology, Faculty of Basic Medical Sciences, Kunming Medical University, 1168 West Chunrong Road, Kunming, 650500, PR China.
| | - Parakalan Rangarajan
- Department of Anatomy, Yong Loo Lin School of Medicine, National University of Singapore, 4 Medical Drive, MD10, Singapore, 117597, Singapore.
| | - Enci Mary Kan
- Defense Medical and Environmental Research Institute, DSO National Laboratories, 27 Medical Drive, Singapore, 117510, Singapore.
| | - Yajun Wu
- Department of Anatomy, Yong Loo Lin School of Medicine, National University of Singapore, 4 Medical Drive, MD10, Singapore, 117597, Singapore.
| | - Chunyun Wu
- Department of Anatomy and Histology/Embryology, Faculty of Basic Medical Sciences, Kunming Medical University, 1168 West Chunrong Road, Kunming, 650500, PR China.
| | - Eng-Ang Ling
- Department of Anatomy, Yong Loo Lin School of Medicine, National University of Singapore, 4 Medical Drive, MD10, Singapore, 117597, Singapore.
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29
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Yuan Y, Zha H, Rangarajan P, Ling EA, Wu C. Anti-inflammatory effects of Edaravone and Scutellarin in activated microglia in experimentally induced ischemia injury in rats and in BV-2 microglia. BMC Neurosci 2014; 15:125. [PMID: 25416145 PMCID: PMC4247200 DOI: 10.1186/s12868-014-0125-3] [Citation(s) in RCA: 91] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Accepted: 11/10/2014] [Indexed: 01/13/2023] Open
Abstract
Background In response to cerebral ischemia, activated microglia release excessive inflammatory mediators which contribute to neuronal damage. Therefore, inhibition of microglial over-activation could be a therapeutic strategy to alleviate various microglia-mediated neuroinflammation. This study was aimed to elucidate the anti-inflammatory effects of Scutellarin and Edaravone given either singly, or in combination in activated microglia in rats subjected to middle cerebral artery occlusion (MCAO), and in lipopolysaccharide (LPS)-induced BV-2 microglia. Expression of proinflammatory cytokines, including tumor necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1β), and inducible nitric oxide synthase (iNOS) was assessed by immunofluorescence staining and Western blot. Reactive oxygen species (ROS) and nitric oxide (NO) levels were determined by flow cytometry and fluorescence microscopy, respectively. Results In vivo, both Edaravone and Scutellarin markedly reduced the infarct cerebral tissue area with the latter drug being more effective with the dosage used; furthermore, when used in combination the reduction was more substantial. Remarkably, a greater diminution in distribution of activated microglia was observed with the combined drug treatment which also attenuated the immunoexpression of TNF-α, IL-1β and iNOS to a greater extent as compared to the drugs given separately. In vitro, both drugs suppressed upregulated expression of inflammatory cytokines, iNOS, NO and ROS in LPS-induced BV-2 cells. Furthermore, Edaravone and Scutellarin in combination cumulatively diminished the expression levels of the inflammatory mediators being most pronounced for TNF-α as evidenced by Western blot. Conclusion The results suggest that Edaravone and Scutellarin effectively suppressed the inflammatory responses in activated microglia, with Scutellarin being more efficacious within the dosage range used. Moreover, when both drugs were used in combination, the infarct tissue area was reduced more extensively; also, microglia-mediated inflammatory mediators notably TNF-α expression was decreased cumulatively. Electronic supplementary material The online version of this article (doi:10.1186/s12868-014-0125-3) contains supplementary material, which is available to authorized users.
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30
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Sohrabji F, Williams M. Stroke neuroprotection: oestrogen and insulin-like growth factor-1 interactions and the role of microglia. J Neuroendocrinol 2013; 25:1173-81. [PMID: 23763366 PMCID: PMC5630268 DOI: 10.1111/jne.12059] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/19/2013] [Revised: 05/30/2013] [Accepted: 06/09/2013] [Indexed: 12/25/2022]
Abstract
Oestrogen has been shown to be neuroprotective for stroke and other neural injury models. Oestrogen promotes a neuroprotective phenotype through myriad actions, including stimulating neurogenesis, promoting neuronal differentiation and survival, suppressing neuroinflammation and maintaining the integrity of the blood-brain barrier. At the molecular level, oestrogen directly modulates genes that are beneficial for repair and regeneration via the canonical oestrogen receptor. Increasingly, evidence indicates that oestrogen acts in concert with growth factors to initiate neuroprotection. Oestrogen and insulin-like growth factor (IGF)-1 act cooperatively to influence cell survival, and combined steroid hormone/growth factor interaction has been well documented in the context of neurones and astrocytes. Here, we summarise the evidence that oestrogen-mediated neuroprotection is critically dependent on IGF-1 signalling, and specifically focus on microglia as the source of IGF-1 and the locus of oestrogen-IGF-1 interactions in stroke neuroprotection.
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Affiliation(s)
- F Sohrabji
- Women's Health in Neuroscience Program, Neuroscience and Experimental Therapeutics, TAMHSC College of Medicine, Bryan, TX, USA
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31
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Murugan M, Ling EA, Kaur C. Dysregulated glutamate uptake by astrocytes causes oligodendroglia death in hypoxic perventricular white matter damage. Mol Cell Neurosci 2013; 56:342-54. [PMID: 23859823 DOI: 10.1016/j.mcn.2013.07.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2012] [Revised: 07/04/2013] [Accepted: 07/08/2013] [Indexed: 01/31/2023] Open
Abstract
Excess glutamate mediates damage to oligodendroglia, resulting in myelination disturbances characteristic of hypoxic periventricular white matter (PWM) damage. We sought to examine if hypoxia altered the expression of astroglial excitatory amino acid transporters (EAAT1, EAAT2 and EAAT3) in the PWM, and, if so, whether it activated astroglial N-methyl D-aspartate receptors (NMDAR) which might lead to apoptosis of oligodendroglia. EAAT expression in the PWM of neonatal rats was measured at different time points after hypoxic exposure; it was attenuated at 7 and 14 d following hypoxia. Hypoxia prevented the uptake of glutamate by astroglial EAATs causing increased levels of extracellular glutamate. Excess glutamate augmented the expression of functional astroglial NMDAR. Following hypoxia, an increase in gap junction proteins between astroglia and oligodendroglia aided in the spreading of NMDAR-mediated excitotoxic calcium signals into the latter cell type triggering its apoptosis. Hence, dysregulated glutamate homeostasis is believed to contribute to hypoxia-induced death of oligodendroglia leading to neonatal PWM damage.
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Affiliation(s)
- Madhuvika Murugan
- Department of Anatomy, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, Singapore
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Li H, Dong H, Li J, Liu H, Liu Z, Li Z. Neuroprotective effect of insulin-like growth factor-1: effects on tyrosine kinase receptor (Trk) expression in dorsal root ganglion neurons with glutamate-induced excitotoxicity in vitro. Brain Res Bull 2013; 97:86-95. [PMID: 23769847 DOI: 10.1016/j.brainresbull.2013.05.014] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2013] [Revised: 05/24/2013] [Accepted: 05/28/2013] [Indexed: 12/13/2022]
Abstract
Insulin-like growth factor-1 (IGF-1) may play an important role in regulating the expression of distinct tyrosine kinase receptor (Trk) in primary sensory dorsal root ganglion (DRG) neurons. Glutamate (Glu) is the main excitatory neurotransmitter and induces neuronal excitotoxicity for primary sensory neurons. It is not known whether IGF-1 influences expression of TrkA, TrkB, and TrkC in DRG neurons with excitotoxicity induced by Glu. In the present study, primary cultured DRG neurons with Glu-induced excitotoxicity were used to determine the effects of IGF-1 on TrkA, TrkB, and TrkC expression. The results showed that IGF-1 increased the expression of TrkA and TrkB and their mRNAs, but not TrkC and its mRNA, in primary cultured DRG neurons with excitotoxicity induced by Glu. Interestingly, neither the extracellular signal-regulated protein kinase (ERK1/2) inhibitor PD98059 nor the phosphatidylinositol 3-kinase (PI3K) inhibitor LY294002 blocked the effect of IGF-1, but both inhibitors together were effective. IGF-1 may play an important role in regulating different Trk receptor expression in DRG neurons through ERK1/2 and PI3K/Akt signaling pathways. The contribution of distinct Trk receptors might be one of the mechanisms that IGF-1 rescues dying neurons from Glu excitotoxic injury. These data imply that IGF-1 signaling might be a potential target on modifying distinct Trk receptor-mediated biological effects of primary sensory neurons with excitotoxicity.
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Affiliation(s)
- Hao Li
- Department of Anatomy, Shandong University School of Medicine, Jinan 250012, China.
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Beppu K, Kosai Y, Kido MA, Akimoto N, Mori Y, Kojima Y, Fujita K, Okuno Y, Yamakawa Y, Ifuku M, Shinagawa R, Nabekura J, Sprengel R, Noda M. Expression, subunit composition, and function of AMPA-type glutamate receptors are changed in activated microglia; possible contribution of GluA2 (GluR-B)-deficiency under pathological conditions. Glia 2013; 61:881-91. [PMID: 23468421 DOI: 10.1002/glia.22481] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2011] [Accepted: 01/23/2013] [Indexed: 01/01/2023]
Abstract
Microglia express AMPA (α-amino-hydroxy-5-methyl-isoxazole-4-propionate)-type of glutamate (Glu) receptors (AMPAR), which are highly Ca(2+) impermeable due to the expression of GluA2. However, the functional importance of AMPAR in microglia remains to be investigated, especially under pathological conditions. As low expression of GluA2 was reported in some neurodegenerative diseases, GluA2(-/-) mice were used to show the functional change of microglial AMPARs in response to Glu or kainate (KA). Here we found that Glu-induced currents in the presence of 100 μM cyclothiazide, an inhibitor of AMPAR desensitization, showed time-dependent decrease after activation of microglia with lipopolysaccharide (LPS) in GluA2(+/+) microglia, but not in GluA2(-/-) microglia. Upon activation of microglia, expression level of GluA2 subunits significantly increased, while expression of GluA1, A3 and A4 subunits on membrane surface significantly decreased. These results suggest that nearly homomeric GluA2 subunits were the main reason for low conductance of AMPAR in activated microglia. Increased expression of GluA2 in microglia was also detected partially in brain slices from LPS-injected mice. Cultured microglia from GluA2(-/-) mice showed higher Ca(2+) -permeability, consequently inducing significant increase in the release of proinflammatory cytokine, such as TNF-α. The conditioning medium from KA-treated GluA2(-/-) microglia had more neurotoxic effect on wild type cultured neurons than that from KA-treated GluA2(+/+) microglia. These results suggest that membrane translocation of GluA2-containing AMPARs in activated microglia has functional importance and thus, dysfunction or decreased expression of GluA2 may accelerate Glu neurotoxicity via excess release of proinflammatory cytokines from microglia.
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Affiliation(s)
- Kaoru Beppu
- Laboratory of Pathophysiology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka 812-8582, Japan
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Kaur C, Sivakumar V, Robinson R, Foulds WS, Luu CD, Ling EA. Neuroprotective effect of melatonin against hypoxia-induced retinal ganglion cell death in neonatal rats. J Pineal Res 2013; 54:190-206. [PMID: 23113620 DOI: 10.1111/jpi.12016] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/24/2012] [Accepted: 09/04/2012] [Indexed: 11/28/2022]
Abstract
The purpose of this study was to determine whether melatonin treatment would mitigate retinal ganglion cell (RGC) death in the developing retina following a hypoxic insult. Lipid peroxidation (LPO), glutathione (GSH), tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) concentrations, expression of vascular endothelial growth factor receptors, Flt-1 and Flk-1, release of cytochrome c from mitochondria, and caspase-3 expression were examined in the retinas of 1-day-old rats at 3 hr to 14 days after a hypoxic exposure. The mRNA and protein expression of Flt-1 and Flk-1 and the tissue concentration of LPO, TNF-α, and IL-1β were upregulated significantly after the hypoxic exposure, whereas the content of GSH was decreased significantly. RGC cultures also showed increased LPO and decreased GSH levels after hypoxic exposure but these effects were reversed in cells treated with melatonin. TNF-α and IL-1β expression was specifically located on microglial cells, whereas Flt-1 and Flk-1 was limited to RGCs as confirmed by double immunofluorescence labeling. Cultures of hypoxic microglial cells treated with melatonin showed a significant reduction in the release of these cytokines as compared to untreated hypoxic cells. Hypoxia induced increase in the cytosolic cytochrome c and caspase-3 in RGCs was attenuated with melatonin treatment. The results suggest that, in hypoxic injuries, melatonin is neuroprotective to RGCs in the developing retina through its antioxidative, anti-inflammatory, and anti-apoptotic effects. Melatonin suppressed Flt-1 and Flk-1 expression in retinal blood vessels, which may result in reduced retinal vascular permeability and it also preserved mitochondrial function as shown by a reduction in cytochrome c leakage into the cytosol. The results may have therapeutic implications for the management of retinopathy of prematurity.
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Affiliation(s)
- Charanjit Kaur
- Department of Anatomy, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.
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Microglia-derived proinflammatory cytokines tumor necrosis factor-alpha and interleukin-1beta induce Purkinje neuronal apoptosis via their receptors in hypoxic neonatal rat brain. Brain Struct Funct 2012; 219:151-70. [PMID: 23262920 DOI: 10.1007/s00429-012-0491-5] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2012] [Accepted: 11/21/2012] [Indexed: 01/19/2023]
Abstract
The developing cerebellum is extremely vulnerable to hypoxia which can damage the Purkinje neurons. We hypothesized that this might be mediated by tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) derived from activated microglia as in other brain areas. One-day-old rats were subjected to hypoxia following, which the expression changes of various proteins in the cerebellum including hypoxia inducible factor-1α, TNF-α, IL-1β, TNF-R1 and IL-1R1 were analyzed. Following hypoxic exposure, TNF-α and IL-1β immunoexpression in microglia was enhanced coupled by that of TNF-R1 and IL-1R1 in the Purkinje neurons. Along with this, hypoxic microglia in vitro showed enhanced release of TNF-α and IL-1β whose receptor expression was concomitantly increased in the Purkinje neurons. In addition, nitric oxide (NO) level was significantly increased in the cerebellum and cultured microglia subjected to hypoxic exposure. Moreover, cultured Purkinje neurons treated with conditioned medium derived from hypoxic microglia underwent apoptosis but the incidence was significantly reduced when the cells were treated with the same medium that was neutralized with TNF-α/IL-1β antibody. We conclude that hypoxic microglia in the neonatal cerebellum produce increased amounts of NO, TNF-α and IL-1β which when acting via their respective receptors could induce Purkinje neuron death.
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López-Pérez S, Morales-Villagrán A, Ventura-Valenzuela J, Medina-Ceja L. Short- and long-term changes in extracellular glutamate and acetylcholine concentrations in the rat hippocampus following hypoxia. Neurochem Int 2012; 61:258-65. [DOI: 10.1016/j.neuint.2012.03.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2011] [Revised: 02/08/2012] [Accepted: 03/13/2012] [Indexed: 01/25/2023]
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Hypoxia-induced activation of N-methyl-D-aspartate receptors causes retinal ganglion cell death in the neonatal retina. J Neuropathol Exp Neurol 2012; 71:330-47. [PMID: 22437343 DOI: 10.1097/nen.0b013e31824deb21] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
It is well established that hypoxia causes excess accumulation of glutamate in developing neural tissues. This study aimed to elucidate the mechanism by which glutamate can cause retinal ganglion cell (RGC) death through the N-methyl-D-aspartate (NMDA) receptors (NR) in the developing retina. One-day-old Wistar rats were exposed to hypoxia for 2 hours and then killed at different time points. Normal age-matched rats were used as controls. NR1, NR2A-D, and NR3A messenger RNA and protein expression showed significant increases over control values, notably at early time points (3 hours to 7 days) after the hypoxic exposure, and immunoexpression of NR1, NR2A-D and NR3A on retinal ganglion cells (RGCs) was enhanced in hypoxic rats and this was confirmed in cultured hypoxic RGCs. Ca(2+) influx in cultured RGCs was increased after hypoxic exposure, and the intracellular Ca(2+) concentration was suppressed by MK-801. Mitochondrial permeability transition pore opening, mitochondrial/cytosolic cytochrome c, and cytosolic caspase-3 expression levels were significantly increased in the hypoxic RGCs. These increases were reversed by MK-801, suggesting that the NMDA receptor subunits in the retina respond rapidly to the hypoxia-induced glutamate overload that leads to the cascade of events that result in RGC death.
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Rosales-Corral SA, Acuña-Castroviejo D, Coto-Montes A, Boga JA, Manchester LC, Fuentes-Broto L, Korkmaz A, Ma S, Tan DX, Reiter RJ. Alzheimer's disease: pathological mechanisms and the beneficial role of melatonin. J Pineal Res 2012; 52:167-202. [PMID: 22107053 DOI: 10.1111/j.1600-079x.2011.00937.x] [Citation(s) in RCA: 210] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Alzheimer's disease (AD) is a highly complex neurodegenerative disorder of the aged that has multiple factors which contribute to its etiology in terms of initiation and progression. This review summarizes these diverse aspects of this form of dementia. Several hypotheses, often with overlapping features, have been formulated to explain this debilitating condition. Perhaps the best-known hypothesis to explain AD is that which involves the role of the accumulation of amyloid-β peptide in the brain. Other theories that have been invoked to explain AD and summarized in this review include the cholinergic hypothesis, the role of neuroinflammation, the calcium hypothesis, the insulin resistance hypothesis, and the association of AD with peroxidation of brain lipids. In addition to summarizing each of the theories that have been used to explain the structural neural changes and the pathophysiology of AD, the potential role of melatonin in influencing each of the theoretical processes involved is discussed. Melatonin is an endogenously produced and multifunctioning molecule that could theoretically intervene at any of a number of sites to abate the changes associated with the development of AD. Production of this indoleamine diminishes with increasing age, coincident with the onset of AD. In addition to its potent antioxidant and anti-inflammatory activities, melatonin has a multitude of other functions that could assist in explaining each of the hypotheses summarized above. The intent of this review is to stimulate interest in melatonin as a potentially useful agent in attenuating and/or delaying AD.
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Affiliation(s)
- Sergio A Rosales-Corral
- Centro de Investigación Biomédica de Occidente del Instituto Mexicano del Seguro Social, Guadalajara, Jalisco, México.
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Kaur C, Rathnasamy G, Ling EA. Roles of activated microglia in hypoxia induced neuroinflammation in the developing brain and the retina. J Neuroimmune Pharmacol 2012; 8:66-78. [PMID: 22367679 DOI: 10.1007/s11481-012-9347-2] [Citation(s) in RCA: 124] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2011] [Accepted: 02/09/2012] [Indexed: 12/14/2022]
Abstract
Amoeboid microglial cells (AMCs) in the developing brain display surface receptors and antigens shared by the monocyte-derived tissue macrophages. Activation of AMCs in the perinatal brain has been associated with periventricular white matter damage in hypoxic-ischemic conditions. The periventricular white matter, where the AMCs preponderate, is selectively vulnerable to hypoxia as manifested by death of premyelinating oligodendrocytes and degeneration of axons leading to neonatal mortality and long-term neurodevelopmental deficits. AMCs respond vigorously to hypoxia by producing excess amounts of inflammatory cytokines e.g. the tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) along with glutamate, nitric oxide (NO) and reactive oxygen species which collectively cause oligodendrocyte death, axonal degeneration as well as disruption of the immature blood brain barrier. A similar phenomenon is observed in the hypoxic developing cerebellum in which activated AMCs induced Purkinje neuronal death through production of TNF-α and IL-1β via their respective receptors. Hypoxia is also implicated in retinopathy of prematurity in which activation of AMCs has been shown to cause retinal ganglion cell death through production of TNF-α and IL-1β and NO. Because AMCs play a pivotal role in hypoxic injuries in the developing brain affecting both neurons and oligodendrocytes, a fuller understanding of the underlying molecular mechanisms of microglial activation under such conditions would be desirable for designing of a novel therapeutic strategy for management of hypoxic damage.
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Affiliation(s)
- Charanjit Kaur
- Department of Anatomy, Yong Loo Lin School of Medicine, National University of Singapore, 4 Medical Drive, MD10, Singapore 117597, Singapore.
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Clavo B, Suarez G, Aguilar Y, Gutierrez D, Ponce P, Cubero A, Robaina F, Carreras JL. Brain ischemia and hypometabolism treated by ozone therapy. ACTA ACUST UNITED AC 2011; 18:283-7. [PMID: 22105041 DOI: 10.1159/000333795] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
BACKGROUND Radiation-induced brain injury (RBI) and low-perfusion brain syndromes are mediated by ischemia and hypometabolism and have limited treatment options. Ozone therapy as treatment in vascular diseases has been described, but the effects on brain tissue have not been well documented. CASE REPORT We describe a 75-year-old patient with vascular risk factors and meningioma who was treated with stereotactic radiosurgery. 14 months later the patient presented with progressive clinical impairment despite the use of acetylsalicylic acid and corticosteroids. Clinical and imaging evaluations before/after ozone therapy were done by magnetic resonance imaging (MRI), computed tomography (CT), single photon emission computed tomography (SPECT), and positron emission tomography (PET); performance status assessment was done using Barthel Index and World Health Organization/Eastern Cooperative Oncology Group Scale (WHO/ECOG Scale). Ozone therapy was performed by autohemotransfusion. RESULTS Basal images showed brain areas with ischemia and hypometabolism compatible with ischemic processes and/or RBI. There were no changes in MRI or CT scan images following ozone therapy. However, improvements in brain perfusion and metabolism were demonstrable with SPECT and PET; they correlated with clinical development and performance status scales. CONCLUSION This report supports our previous works about the effect of ozone therapy in cerebral blood flow, and it suggests the use of ozone therapy in ischemic and hypometabolic brain syndromes such as stroke or RBI.
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Affiliation(s)
- Bernardino Clavo
- Department of Radiation Oncology, Chronic Pain Unit and Research Unit, Dr. Negrin University Hospital, Las Palmas, Spain.
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Cao Q, Kaur C, Wu CY, Lu J, Ling EA. Nuclear factor-kappa β regulates Notch signaling in production of proinflammatory cytokines and nitric oxide in murine BV-2 microglial cells. Neuroscience 2011; 192:140-54. [PMID: 21729740 DOI: 10.1016/j.neuroscience.2011.06.060] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2011] [Revised: 06/21/2011] [Accepted: 06/21/2011] [Indexed: 11/25/2022]
Abstract
Microglial cells exhibit Notch-1 signaling expression which is enhanced upon activation. We reported previously that enhanced Notch-1 expression in activated microglia modulates production of proinflammatory cytokines and nitric oxide (NO). Furthermore, Notch-1 modulates transcription factor nuclear factor-kappa B (NF-κB). This study was aimed to investigate if NF-κB reciprocally modulates Notch signaling in BV-2 cells. In this connection, the cells were pretreated with caffeic acid phenethyl ester (Cape) followed by stimulating the cells with lipopolysaccharide (LPS). Cape+LPS treatment resulted in reduced translocation of NF-κB into the nucleus. Concomitantly, NF-κB DNA binding activity and the mRNA and protein expression levels of NF-κB/p65, Notch-1, intracellular domain of Notch-1 receptor (NICD), Hes-1, tumor necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1β) and inducible nitric oxide synthase (iNOS) along with nitrite level were significantly reduced. Additionally, flow cytometry analysis showed a decrease in expression levels of NF-κB/p65, Notch-1, NICD but an increase in that of signal transducers and activators of transcription 3 (Stat3). Furthermore, nuclear Hes-1, phosphorylated Stat3 (p-Stat3) and recombination signal-binding protein 1 for J-Kappa (RBP-JK) expression levels were significantly suppressed. The present results suggest that Cape inhibits NF-κB activation through suppressing its interaction with DNA. Cape-induced reduction of Hes-1 may be attributed to decreased interaction between NICD and RBP-JK whose levels were reduced concurrently. Hes-1 reduction may lead to decreased production of inflammatory cytokines and NO. It is concluded that NF-κB can modulate Notch-1 signaling. Both pathways operate synergistically for production of proinflammatory cytokines and NO in activated microglia.
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Affiliation(s)
- Q Cao
- Department of Anatomy, Block MD 10, 4 Medical Drive, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597
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Solaroglu A, Suat Dede F, Gelisen O, Secilmis O, Dede H. Neuroprotective effect of magnesium sulfate treatment on fetal brain in experimental intrauterine ischemia reperfusion injury. J Matern Fetal Neonatal Med 2011; 24:1259-61. [DOI: 10.3109/14767058.2011.572202] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Cao Q, Li P, Lu J, Dheen ST, Kaur C, Ling EA. Nuclear factor-κB/p65 responds to changes in the Notch signaling pathway in murine BV-2 cells and in amoeboid microglia in postnatal rats treated with the γ-secretase complex blocker DAPT. J Neurosci Res 2011; 88:2701-14. [PMID: 20648656 DOI: 10.1002/jnr.22429] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Microglial cells constitutively express Notch-1 and nuclear factor-kappaB/p65 (NF-kappaB/p65), and both pathways modulate production of inflammatory mediators. This study sought to determine whether a functional relationship exists between them and, if so, to investigate whether they synergistically regulate common microglial cell functions. By immunofluorescence labeling, real-time polymerase chain reaction (RT-PCR), flow cytometry, and Western blot, BV-2 cells exhibited Notch-1 and NF-kappaB/p65 expression, which was significantly up-regulated in cells challenged with lipopolysaccharide (LPS). This was coupled with an increase in expression of Hes-1, tumor necrosis factor-alpha (TNF-alpha), and interleukin-1beta (IL-1beta). In BV-2 cells pretreated with N-[N-(3,5-difluorophenacetyl)-1-alany1]-S-phenyglycine t-butyl ester (DAPT), a gamma-secretase inhibitor, followed by LPS stimulation, Notch-1 expression level was enhanced but that of all other markers was suppressed. Additionally, Hes-1 expression and NF-kappaB nuclear translocation decreased as shown by flow cytometry. Notch-1's modulation of NF-kappaB/p65 was also evidenced in amoeboid microglial cells (AMC) in vivo. In 5-day-old rats given intraperitoneal injections of LPS, Notch-1, NF-kappaB/p65, TNF-alpha, and IL-1beta immunofluorescence in AMC was markedly enhanced. However, in rats given an intraperitoneal injection of DAPT prior to LPS, Notch-1 labeling was augmented, but that of TNF-alpha and IL-1beta was reduced. The results suggest that blocking of Notch-1 activation with DAPT would reduce the level of its downstream end product Hes-1 along with suppression of NF-kappaB/p65 translocation, resulting in suppressed production of proinflammatory cytokines. It is concluded that Notch-1 signaling can trans-activate NF-kappaB/p65 by amplifying NF-kappaB/p65-dependent proinflammatory functions in activated microglia.
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Affiliation(s)
- Q Cao
- Department of Anatomy, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597
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Expression of sphingosine kinase 1 in amoeboid microglial cells in the corpus callosum of postnatal rats. J Neuroinflammation 2011; 8:13. [PMID: 21310085 PMCID: PMC3050721 DOI: 10.1186/1742-2094-8-13] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2011] [Accepted: 02/11/2011] [Indexed: 11/21/2022] Open
Abstract
Sphingosine kinase 1 (SphK1), a key enzyme responsible for phosphorylating sphingosine into sphingosine-1-phosphate (S1P) has been shown to be expressed in monocytes and monocyte-derived peripheral macrophages. This study demonstrates SphK1 immunoexpression in amoeboid microglial cells (AMC), a nascent monocyte-derived brain macrophage in the corpus callosum of developing rat brain. SphK1 immunofluorescence expression, which appeared to be weak in AMC in normal brain, was markedly induced by lipopolysaccharide (LPS) or hypoxia treatment. Western blot analysis also showed increased expression level of SphK1 in the corpus callosum rich in AMC after LPS treatment. Detection of SphK1 mRNA and its upregulation after LPS treatment was confirmed in primary culture AMC by RT-PCR. Administration of N, N-dimethylsphingosine (DMS), a specific inhibitor of SphK1, effectively reduced upregulated SphK1 immunoexpression in AMC both in vivo and in vitro. This was corroborated by western blot which showed a decrease in SphK1 protein level of callosal tissue with DMS pretreatment. Remarkably, LPS-induced upregulation of the transcription factor NFκB was suppressed by DMS. We conclude that SphK1 expression in AMC may be linked to regulation of proinflammatory cytokines via an NFκB signaling pathway.
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Murugan M, Sivakumar V, Lu J, Ling EA, Kaur C. Expression of N-methyl D-aspartate receptor subunits in amoeboid microglia mediates production of nitric oxide via NF-κB signaling pathway and oligodendrocyte cell death in hypoxic postnatal rats. Glia 2011; 59:521-39. [PMID: 21319220 DOI: 10.1002/glia.21121] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2010] [Accepted: 11/11/2010] [Indexed: 11/10/2022]
Abstract
The present study was focused on identifying the expression of N-methyl D-aspartate receptor (NMDAR) subunits on activated microglia and to determine their role in the pathogenesis of periventricular white matter damage (PWMD) in neonatal rats following hypoxia. One day old wistar rats were subjected to hypoxia (5% O(2) ; 95% N(2) ) and the mRNA and protein expression of NMDAR subunits (NR1, NR2A-D, and NR3A) in the periventricular white matter (PWM) was determined at different time points (3,24 h, 3, 7, and 14 days) following hypoxic exposure. Immunoexpression of NR1 and NR2A-D was localized in amoeboid microglial cells (AMC) suggesting the presence of functional NMDARs in them. The expression of NMDAR in primary microglial cultures was ascertained by RT-PCR analysis and double immunofluorescence studies. The functionality of the microglial NMDAR in cultured microglial cells was examined by monitoring calcium movements in cells with fura-2. In primary microglial cultures, hypoxia induced the nuclear translocation of NF-κB which was suppressed by administration of MK801, an NMDAR antagonist. MK801 also down regulated the hypoxia-induced expression of tumor necrosis factor-α, interleukin-1β, inducible nitric oxide synthase (iNOS), and nitric oxide (NO) production by microglia which may be mediated by the NF-κB signaling pathway. NO produced by microglia is known to cause death of oligodendrocytes in the developing PWM. In this connection, pharmacological agents such as MK801, BAY (NF-κB inhibitor), and 1400w (iNOS inhibitor) proved to be beneficial since they reduced the hypoxia-induced iNOS expression, NO production, and a corresponding reduction in the death of oligodendrocytes following hypoxia.
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Affiliation(s)
- Madhuvika Murugan
- Department of Anatomy, Yong Loo Lin School of Medicine, Blk MD10, 4 Medical Drive, National University of Singapore, Singapore
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Swamy M, Salleh MJM, Sirajudeen KNS, Yusof WRW, Chandran G. Nitric oxide (no), citrulline - no cycle enzymes, glutamine synthetase and oxidative stress in anoxia (hypobaric hypoxia) and reperfusion in rat brain. Int J Med Sci 2010; 7:147-54. [PMID: 20567615 PMCID: PMC2880843 DOI: 10.7150/ijms.7.147] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2009] [Accepted: 05/26/2010] [Indexed: 12/31/2022] Open
Abstract
Nitric oxide is postulated to be involved in the pathophysiology of neurological disorders due to hypoxia/ anoxia in brain due to increased release of glutamate and activation of N-methyl-D-aspartate receptors. Reactive oxygen species have been implicated in pathophysiology of many neurological disorders and in brain function. To understand their role in anoxia (hypobaric hypoxia) and reperfusion (reoxygenation), the nitric oxide synthase, argininosuccinate synthetase, argininosuccinate lyase, glutamine synthetase and arginase activities along with the concentration of nitrate /nitrite, thiobarbituric acid reactive substances and total antioxidant status were estimated in cerebral cortex, cerebellum and brain stem of rats subjected to anoxia and reperfusion. The results of this study clearly demonstrated the increased production of nitric oxide by increased activity of nitric oxide synthase. The increased activities of argininosuccinate synthetase and argininosuccinate lyase suggest the increased and effective recycling of citrulline to arginine in anoxia, making nitric oxide production more effective and contributing to its toxic effects. The decreased activity of glutamine synthetase may favor the prolonged availability of glutamic acid causing excitotoxicity leading to neuronal damage in anoxia. The increased formation of thiobarbituric acid reactive substances and decreased total antioxidant status indicate the presence of oxidative stress in anoxia and reperfusion. The increased arginase and sustained decrease of GS activity in reperfusion group likely to be protective.
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Affiliation(s)
- M Swamy
- Department of Chemical Pathology, School of Medical Sciences, Health campus, Universiti Sains Malaysia, 16150 Kubang Kerian, Kelantan, Malaysia.
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Abstract
This study investigated the potential of melatonin in ameliorating hypoxic damage to the periventricular white matter (PWM) in the neonatal brain. Vascular endothelial growth factor (VEGF), nitric oxide (NO), glutathione (GSH) and malondialdehyde (MDA) content in the PWM of 1-day-old rats subjected to hypoxia for a period of 2 hr was examined. Vascular endothelial growth factor, NO and MDA concentration was increased whereas that of GSH was reduced after the hypoxic exposure. Additionally, degenerating axons, apoptotic and necrotic cells and vacuolation of capillary endothelial cells were observed in the PWM. The neighboring ependymal and choroid plexus cells also appeared to undergo structural alterations. Increased vascular permeability in the PWM of hypoxic rats was evidenced by the leakage of rhodamine isothiocyanate (RhIC) which was taken up by the amoeboid microglial cells. In vitro experiments showed increased apoptosis in OLN-93 cells, an oligodendrocytic cell line, following hypoxic exposure. Hypoxic rats treated with melatonin showed reduced VEGF, NO and MDA concentrations, increased GSH content and reduced RhIC leakage in the PWM. The ultrastructure of axons, endothelial, ependymal and choroid plexus epithelial cells appeared relatively normal in the hypoxic animals treated with melatonin. The incidence of apoptotic OLN-93 cells was also reduced with melatonin treatment. We suggest that the protective effects of melatonin on various parameters in the PWM of hypoxic neonatal brains were due to its antioxidant properties.
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Affiliation(s)
- C Kaur
- Department of Anatomy, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - V Sivakumar
- Department of Anatomy, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - E A Ling
- Department of Anatomy, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
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