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Liu T, Bai M, Liu M, Li T, Liao Y, Zhao C, Yao M, Wang J, Wen A, Ding Y. Novel synergistic mechanism of 11-keto-β-boswellic acid and Z-Guggulsterone on ischemic stroke revealed by single-cell transcriptomics. Pharmacol Res 2023:106803. [PMID: 37230158 DOI: 10.1016/j.phrs.2023.106803] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/26/2023] [Revised: 05/11/2023] [Accepted: 05/22/2023] [Indexed: 05/27/2023]
Abstract
Although strides have been made, the challenge of preventing and treating ischemic stroke continues to persist globally. For thousands of years, the natural substances Frankincense and Myrrh have been employed in Chinese and Indian medicine to address cerebrovascular diseases, with the key components of 11-keto-β-boswellic acid (KBA) and Z-Guggulsterone (Z-GS) being the active agents. In this study, the synergistic effect and underlying mechanism of KBA and Z-GS on ischemic stroke were examined using single-cell transcriptomics. Fourteen cell types were identified in KBA-Z-GS-treated ischemic penumbra, and microglia and astrocytes account for the largest proportion. They were further re-clustered into six and seven subtypes, respectively. GSVA analysis reflected the distinct roles of each subtype. Pseudo-time trajectory indicated that Slc1a2 and Timp1 were core fate transition genes regulated by KBA-Z-GS. In addition, KBA-Z-GS synergistically regulated inflammatory reactions in microglia and cellular metabolism and ferroptosis in astrocytes. Most notably, we established an innovative drug-gene synergistic regulation pattern, and genes regulated by KBA-Z-GS were divided into four categories based on this pattern. Finally, Spp1 was demonstrated as the hub target of KBA-Z-GS. Taken together, this study reveals the synergistic mechanism of KBA and Z-GS on cerebral ischemia, and Spp1 may be the synergistic target for that. Precise drug development targeting Spp1 may offer a potential therapeutic approach for treating ischemic stroke.
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Affiliation(s)
- Tianlong Liu
- Department of Pharmacy, Xijing Hospital, Fourth Military Medical University, Xi'an, 710032, China; Department of Pharmacy, The 940th Hospital Joint Logistics Support Forces of PLA, Lanzhou, 730050, China
| | - Min Bai
- Department of Pharmacy, Xijing Hospital, Fourth Military Medical University, Xi'an, 710032, China
| | - Minna Liu
- Department of Nephrology, The 940th Hospital Joint Logistics Support Forces of PLA, Lanzhou, 730050, China
| | - Tian Li
- School of Basic Medicine, Fourth Military Medical University, Xi'an, 710032, China
| | - Yucheng Liao
- Department of Pharmacy, Xijing Hospital, Fourth Military Medical University, Xi'an, 710032, China
| | - Chao Zhao
- Department of Pharmacy, Xijing Hospital, Fourth Military Medical University, Xi'an, 710032, China
| | - Minna Yao
- Department of Pharmacy, Xijing Hospital, Fourth Military Medical University, Xi'an, 710032, China
| | - Jingwen Wang
- Department of Pharmacy, Xijing Hospital, Fourth Military Medical University, Xi'an, 710032, China.
| | - Aidong Wen
- Department of Pharmacy, Xijing Hospital, Fourth Military Medical University, Xi'an, 710032, China.
| | - Yi Ding
- Department of Pharmacy, Xijing Hospital, Fourth Military Medical University, Xi'an, 710032, China.
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Espinosa JM, Castellano JM, Garcia-Rodriguez S, Quintero-Flórez A, Carrasquilla N, Perona JS. Lipophilic Bioactive Compounds Transported in Triglyceride-Rich Lipoproteins Modulate Microglial Inflammatory Response. Int J Mol Sci 2022; 23:ijms23147706. [PMID: 35887052 PMCID: PMC9321013 DOI: 10.3390/ijms23147706] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Revised: 06/30/2022] [Accepted: 07/09/2022] [Indexed: 11/16/2022] Open
Abstract
Microglial cells can contribute to Alzheimer’s disease by triggering an inflammatory response that leads to neuronal death. In addition, the presence of amyloid-β in the brain is consistent with alterations in the blood–brain barrier integrity and triglyceride-rich lipoproteins (TRL) permeation. In the present work, we used lab-made TRL as carriers of lipophilic bioactive compounds that are commonly present in dietary oils, namely oleanolic acid (OA), α-tocopherol (AT) and β-sitosterol (BS), to assess their ability to modulate the inflammatory response of microglial BV-2 cells. We show that treatment with lab-made TRL increases the release and gene-expression of IL-1β, IL-6, and TNF-α, as well as NO and iNOS in microglia. On the other hand, TRL revealed bioactive compounds α-tocopherol and β-sitosterol as suitable carriers for oleanolic acid. The inclusion of these biomolecules in TRL reduced the release of proinflammatory cytokines. The inclusion of these biomolecules in TRL reduced the release of proinflammatory cytokines. AT reduced IL-6 release by 72%, OA reduced TNF-α release by approximately 50%, and all three biomolecules together (M) reduced IL-1β release by 35% and TNF-α release by more than 70%. In addition, NO generation was reduced, with the inclusion of OA by 45%, BS by 80% and the presence of M by 88%. Finally, a recovery of the basal glutathione content was observed with the inclusion of OA and M in the TRL. Our results open the way to exploiting the neuro-pharmacological potential of these lipophilic bioactive compounds through their delivery to the brain as part of TRL.
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Events Occurring in the Axotomized Facial Nucleus. Cells 2022; 11:cells11132068. [PMID: 35805151 PMCID: PMC9266054 DOI: 10.3390/cells11132068] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Revised: 06/26/2022] [Accepted: 06/27/2022] [Indexed: 01/27/2023] Open
Abstract
Transection of the rat facial nerve leads to a variety of alterations not only in motoneurons, but also in glial cells and inhibitory neurons in the ipsilateral facial nucleus. In injured motoneurons, the levels of energy metabolism-related molecules are elevated, while those of neurofunction-related molecules are decreased. In tandem with these motoneuron changes, microglia are activated and start to proliferate around injured motoneurons, and astrocytes become activated for a long period without mitosis. Inhibitory GABAergic neurons reduce the levels of neurofunction-related molecules. These facts indicate that injured motoneurons somehow closely interact with glial cells and inhibitory neurons. At the same time, these events allow us to predict the occurrence of tissue remodeling in the axotomized facial nucleus. This review summarizes the events occurring in the axotomized facial nucleus and the cellular and molecular mechanisms associated with each event.
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Starovoytova IA, Dominova IN. An in vitro Study of the Effect of Bacterial Lipopolysaccharide on Transcription Levels of SLC Family Transporter Genes in Microglia. J EVOL BIOCHEM PHYS+ 2022. [DOI: 10.1134/s0022093022020193] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Avalos MP, Guzman AS, Rigoni D, Gorostiza EA, Sanchez MA, Mongi-Bragato B, Garcia-Keller C, Perassi EM, Virgolini MB, Peralta Ramos JM, Iribarren P, Calfa GD, Bollati FA, Cancela LM. Minocycline prevents chronic restraint stress-induced vulnerability to developing cocaine self-administration and associated glutamatergic mechanisms: a potential role of microglia. Brain Behav Immun 2022; 101:359-376. [PMID: 35065197 DOI: 10.1016/j.bbi.2022.01.014] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 12/24/2021] [Accepted: 01/16/2022] [Indexed: 12/14/2022] Open
Abstract
Stressful experience-induced cocaine-related behaviors are associated with a significant impairment of glutamatergic mechanisms in the Nucleus Accumbens core (NAcore). The hallmarks of disrupted glutamate homeostasis following restraint stress are the enduring imbalance of glutamate efflux after a cocaine stimulus and increased basal concentrations of extracellular glutamate attributed to GLT-1 downregulation in the NAcore. Glutamate transmission is tightly linked to microglia functioning. However, the role of microglia in the biological basis of stress-induced addictive behaviors is still unknown. By using minocycline, a potent inhibitor of microglia activation with anti-inflammatory properties, we determined whether microglia could aid chronic restraint stress (CRS)-induced glutamate homeostasis disruption in the NAcore, underpinning stress-induced cocaine self-administration. In this study, adult male rats were restrained for 2 h/day for seven days (day 1-7). From day 16 until completing the experimental protocol, animals received a vehicle or minocycline treatment (30 mg/Kg/12h i.p.). On day 21, animals were assigned to microscopic, biochemical, neurochemical or behavioral studies. We confirm that the CRS-induced facilitation of cocaine self-administration is associated with enduring GLT-1 downregulation, an increase of basal extracellular glutamate and postsynaptic structural plasticity in the NAcore. These alterations were strongly related to the CRS-induced reactive microglia and increased TNF-α mRNA and protein expression, since by administering minocycline, the impaired glutamate homeostasis and the facilitation of cocaine self-administration were prevented. Our findings are the first to demonstrate that minocycline suppresses the CRS-induced facilitation of cocaine self-administration and glutamate homeostasis disruption in the NAcore. A role of microglia is proposed for the development of glutamatergic mechanisms underpinning stress-induced vulnerability to cocaine addiction.
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Affiliation(s)
- María Paula Avalos
- Instituto de Farmacología Experimental de Córdoba (IFEC-CONICET), Departamento de Farmacología, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, X5000HUA, Córdoba, Argentina
| | - Andrea Susana Guzman
- Instituto de Farmacología Experimental de Córdoba (IFEC-CONICET), Departamento de Farmacología, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, X5000HUA, Córdoba, Argentina
| | - Daiana Rigoni
- Instituto de Farmacología Experimental de Córdoba (IFEC-CONICET), Departamento de Farmacología, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, X5000HUA, Córdoba, Argentina
| | - Ezequiel Axel Gorostiza
- Instituto de Farmacología Experimental de Córdoba (IFEC-CONICET), Departamento de Farmacología, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, X5000HUA, Córdoba, Argentina
| | - Marianela Adela Sanchez
- Instituto de Farmacología Experimental de Córdoba (IFEC-CONICET), Departamento de Farmacología, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, X5000HUA, Córdoba, Argentina
| | - Bethania Mongi-Bragato
- Instituto de Farmacología Experimental de Córdoba (IFEC-CONICET), Departamento de Farmacología, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, X5000HUA, Córdoba, Argentina
| | - Constanza Garcia-Keller
- Instituto de Farmacología Experimental de Córdoba (IFEC-CONICET), Departamento de Farmacología, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, X5000HUA, Córdoba, Argentina
| | - Eduardo Marcelo Perassi
- Instituto de Investigaciones en Fisicoquímica de Córdoba (INFIQC-CONICET), Departamento de Química Teórica y Computacional, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, X5000HUA, Córdoba, Argentina
| | - Miriam Beatriz Virgolini
- Instituto de Farmacología Experimental de Córdoba (IFEC-CONICET), Departamento de Farmacología, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, X5000HUA, Córdoba, Argentina
| | - Javier María Peralta Ramos
- Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI-CONICET), Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, X5000HUA, Córdoba, Argentina
| | - Pablo Iribarren
- Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI-CONICET), Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, X5000HUA, Córdoba, Argentina
| | - Gastón Diego Calfa
- Instituto de Farmacología Experimental de Córdoba (IFEC-CONICET), Departamento de Farmacología, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, X5000HUA, Córdoba, Argentina
| | - Flavia Andrea Bollati
- Instituto de Farmacología Experimental de Córdoba (IFEC-CONICET), Departamento de Farmacología, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, X5000HUA, Córdoba, Argentina.
| | - Liliana Marina Cancela
- Instituto de Farmacología Experimental de Córdoba (IFEC-CONICET), Departamento de Farmacología, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, X5000HUA, Córdoba, Argentina.
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Quincozes-Santos A, Santos CL, de Souza Almeida RR, da Silva A, Thomaz NK, Costa NLF, Weber FB, Schmitz I, Medeiros LS, Medeiros L, Dotto BS, Dias FRP, Sovrani V, Bobermin LD. Gliotoxicity and Glioprotection: the Dual Role of Glial Cells. Mol Neurobiol 2021; 58:6577-6592. [PMID: 34581988 PMCID: PMC8477366 DOI: 10.1007/s12035-021-02574-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Accepted: 09/19/2021] [Indexed: 02/06/2023]
Abstract
Glial cells (astrocytes, oligodendrocytes and microglia) are critical for the central nervous system (CNS) in both physiological and pathological conditions. With this in mind, several studies have indicated that glial cells play key roles in the development and progression of CNS diseases. In this sense, gliotoxicity can be referred as the cellular, molecular, and neurochemical changes that can mediate toxic effects or ultimately lead to impairment of the ability of glial cells to protect neurons and/or other glial cells. On the other hand, glioprotection is associated with specific responses of glial cells, by which they can protect themselves as well as neurons, resulting in an overall improvement of the CNS functioning. In addition, gliotoxic events, including metabolic stresses, inflammation, excitotoxicity, and oxidative stress, as well as their related mechanisms, are strongly associated with the pathogenesis of neurological, psychiatric and infectious diseases. However, glioprotective molecules can prevent or improve these glial dysfunctions, representing glial cells-targeting therapies. Therefore, this review will provide a brief summary of types and functions of glial cells and point out cellular and molecular mechanisms associated with gliotoxicity and glioprotection, potential glioprotective molecules and their mechanisms, as well as gliotherapy. In summary, we expect to address the relevance of gliotoxicity and glioprotection in the CNS homeostasis and diseases.
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Affiliation(s)
- André Quincozes-Santos
- Programa de Pós-Graduação Em Ciências Biológicas: Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal Do Rio Grande Do Sul, Porto Alegre, RS, Brazil.
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal Do Rio Grande Do Sul, Porto Alegre, RS, Brazil.
- Programa de Pós-Graduação Em Neurociências, Instituto de Ciências Básicas da Saúde, Universidade Federal Do Rio Grande Do Sul, Porto Alegre, RS, Brazil.
| | - Camila Leite Santos
- Programa de Pós-Graduação Em Ciências Biológicas: Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal Do Rio Grande Do Sul, Porto Alegre, RS, Brazil
| | - Rômulo Rodrigo de Souza Almeida
- Programa de Pós-Graduação Em Ciências Biológicas: Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal Do Rio Grande Do Sul, Porto Alegre, RS, Brazil
| | - Amanda da Silva
- Programa de Pós-Graduação Em Ciências Biológicas: Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal Do Rio Grande Do Sul, Porto Alegre, RS, Brazil
| | - Natalie K Thomaz
- Programa de Pós-Graduação Em Ciências Biológicas: Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal Do Rio Grande Do Sul, Porto Alegre, RS, Brazil
| | - Naithan Ludian Fernandes Costa
- Programa de Pós-Graduação Em Neurociências, Instituto de Ciências Básicas da Saúde, Universidade Federal Do Rio Grande Do Sul, Porto Alegre, RS, Brazil
| | - Fernanda Becker Weber
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal Do Rio Grande Do Sul, Porto Alegre, RS, Brazil
| | - Izaviany Schmitz
- Programa de Pós-Graduação Em Ciências Biológicas: Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal Do Rio Grande Do Sul, Porto Alegre, RS, Brazil
| | - Lara Scopel Medeiros
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal Do Rio Grande Do Sul, Porto Alegre, RS, Brazil
| | - Lívia Medeiros
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal Do Rio Grande Do Sul, Porto Alegre, RS, Brazil
| | - Bethina Segabinazzi Dotto
- Programa de Pós-Graduação Em Ciências Biológicas: Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal Do Rio Grande Do Sul, Porto Alegre, RS, Brazil
| | - Filipe Renato Pereira Dias
- Programa de Pós-Graduação Em Ciências Biológicas: Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal Do Rio Grande Do Sul, Porto Alegre, RS, Brazil
| | - Vanessa Sovrani
- Programa de Pós-Graduação Em Ciências Biológicas: Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal Do Rio Grande Do Sul, Porto Alegre, RS, Brazil
| | - Larissa Daniele Bobermin
- Programa de Pós-Graduação Em Ciências Biológicas: Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal Do Rio Grande Do Sul, Porto Alegre, RS, Brazil
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Lim SW, Su HC, Nyam TTE, Chio CC, Kuo JR, Wang CC. Ceftriaxone therapy attenuates brain trauma in rats by affecting glutamate transporters and neuroinflammation and not by its antibacterial effects. BMC Neurosci 2021; 22:54. [PMID: 34521349 PMCID: PMC8439027 DOI: 10.1186/s12868-021-00659-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Accepted: 09/04/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Ceftriaxone is a β-lactam antibiotic used to treat central nervous system infections. Whether the neuroprotective effects of ceftriaxone after TBI are mediated by attenuating neuroinflammation but not its antibacterial actions is not well established. METHODS Anesthetized male Sprague-Dawley rats were divided into sham-operated, TBI + vehicle, and TBI + ceftriaxone groups. Ceftriaxone was intraperitoneally injected at 0, 24, and 48 h with 50 or 250 mg/kg/day after TBI. During the first 120 min after TBI, we continuously measured heart rate, arterial pressure, intracranial pressure (ICP), and cerebral perfusion pressure. The infarct volume was measured by TTC staining. Motor function was measured using the inclined plane. Glutamate transporter 1 (GLT-1), neuronal apoptosis and TNF-α expression in the perilesioned cortex were investigated using an immunofluorescence assay. Bacterial evaluation was performed by Brown and Brenn's Gram staining. These parameters above were measured at 72 h after TBI. RESULTS Compared with the TBI + vehicle group, the TBI + ceftriaxone 250 mg/kg group showed significantly lower ICP, improved motor dysfunction, reduced body weight loss, decreased infarct volume and neuronal apoptosis, decreased TBI-induced microglial activation and TNF-α expression in microglia, and increased GLT-1 expression in neurons and microglia. However, the grades of histopathological changes of antibacterial effects are zero. CONCLUSIONS The intraperitoneal injection of ceftriaxone with 250 mg/kg/day for three days may attenuate TBI by increasing GLT-1 expression and reducing neuroinflammation and neuronal apoptosis, thereby resulting in an improvement in functional outcomes, and this neuroprotective effect is not related to its antibacterial effects.
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Affiliation(s)
- Sher-Wei Lim
- Department of Neurosurgery, Chi-Mei Medical Center, Chiali, Tainan, Taiwan
- Department of Nursing, Min-Hwei College of Health Care Management, Tainan, Taiwan
| | - Hui-Chen Su
- Departments of Pharmacy, Chi-Mei Medical Center, Tainan, Taiwan
| | - Tee-Tau Eric Nyam
- Departments of Neurosurgery, Chi-Mei Medical Center, 901 Chung Hwa Road, Yung Kang City, Tainan, Taiwan
| | - Chung-Ching Chio
- Departments of Neurosurgery, Chi-Mei Medical Center, 901 Chung Hwa Road, Yung Kang City, Tainan, Taiwan
| | - Jinn-Rung Kuo
- Departments of Neurosurgery, Chi-Mei Medical Center, 901 Chung Hwa Road, Yung Kang City, Tainan, Taiwan
- Departments of Medical Research, Chi-Mei Medical Center, Tainan, Taiwan
| | - Che-Chuan Wang
- Departments of Neurosurgery, Chi-Mei Medical Center, 901 Chung Hwa Road, Yung Kang City, Tainan, Taiwan
- Departments of Medical Research, Chi-Mei Medical Center, Tainan, Taiwan
- Center for General Education, Southern Taiwan University of Science and Technology, Tainan, Taiwan
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Abstract
Glutathione (GSH) is the most abundant non-protein thiol, and plays crucial roles in the antioxidant defense system and the maintenance of redox homeostasis in neurons. GSH depletion in the brain is a common finding in patients with neurodegenerative diseases, such as Alzheimer’s disease and Parkinson’s disease, and can cause neurodegeneration prior to disease onset. Excitatory amino acid carrier 1 (EAAC1), a sodium-dependent glutamate/cysteine transporter that is selectively present in neurons, plays a central role in the regulation of neuronal GSH production. The expression of EAAC1 is posttranslationally controlled by the glutamate transporter-associated protein 3–18 (GTRAP3-18) or miR-96-5p in neurons. The regulatory mechanism of neuronal GSH production mediated by EAAC1 may be a new target in therapeutic strategies for these neurodegenerative diseases. This review describes the regulatory mechanism of neuronal GSH production and its potential therapeutic application in the treatment of neurodegenerative diseases.
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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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Loewen JL, Albertini G, Dahle EJ, Sato H, Smolders IJ, Massie A, Wilcox KS. Genetic and pharmacological manipulation of glial glutamate transporters does not alter infection-induced seizure activity. Exp Neurol 2019; 318:50-60. [PMID: 31022385 DOI: 10.1016/j.expneurol.2019.04.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Revised: 03/19/2019] [Accepted: 04/20/2019] [Indexed: 12/11/2022]
Abstract
The contribution of glial transporters to glutamate movement across the membrane has been identified as a potential target for anti-seizure therapies. Two such glutamate transporters, GLT-1 and system xc-, are expressed on glial cells, and modulation of their expression and function have been identified as a means by which seizures, neuronal injury, and gliosis can be reduced in models of brain injury. While GLT-1 is responsible for the majority of glutamate uptake in the brain, system xc- releases glutamate in the extracellular cleft in exchange for cystine and represents as such the major source of hippocampal extracellular glutamate. Using the Theiler's Murine Encephalomyelitis Virus (TMEV) model of viral-induced epilepsy, we have taken two well-studied approaches, one pharmacological, one genetic, to investigate the potential role(s) of GLT-1 and system xc- in TMEV-induced pathology. Our findings suggest that the methods we utilized to modulate these glial transporters, while effective in other models, are not sufficient to reduce the number or severity of behavioral seizures in TMEV-infected mice. However, genetic knockout of xCT, the specific subunit of system xc-, may have cellular effects, as we observed a slight decrease in neuronal injury caused by TMEV and an increase in astrogliosis in the CA1 region of the hippocampus. Furthermore, xCT knockout caused an increase in GLT-1 expression selectively in the cortex. These findings have significant implications for both the characterization of the TMEV model as well as for future efforts to discover novel and effective anti-seizure drugs.
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Affiliation(s)
- Jaycie L Loewen
- Department of Pharmacology and Toxicology, University of Utah, USA; Interdepartmental Program in Neuroscience, University of Utah, USA
| | - Giulia Albertini
- Department of Pharmaceutical Chemistry, Drug Analysis and Drug Information, Center for Neurosciences (C4N), Vrije Universiteit Brussel, Belgium
| | - E Jill Dahle
- Department of Pharmacology and Toxicology, University of Utah, USA
| | - Hideyo Sato
- Department of Medical Technology, Niigata University, Japan
| | - Ilse J Smolders
- Department of Pharmaceutical Chemistry, Drug Analysis and Drug Information, Center for Neurosciences (C4N), Vrije Universiteit Brussel, Belgium
| | - Ann Massie
- Department of Pharmaceutical Biotechnology and Molecular Biology, C4N, Vrije Universiteit Brussel, Belgium
| | - Karen S Wilcox
- Department of Pharmacology and Toxicology, University of Utah, USA; Interdepartmental Program in Neuroscience, University of Utah, USA.
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Milanova IV, Kalsbeek MJT, Wang XL, Korpel NL, Stenvers DJ, Wolff SEC, de Goede P, Heijboer AC, Fliers E, la Fleur SE, Kalsbeek A, Yi CX. Diet-Induced Obesity Disturbs Microglial Immunometabolism in a Time-of-Day Manner. Front Endocrinol (Lausanne) 2019; 10:424. [PMID: 31316470 PMCID: PMC6611391 DOI: 10.3389/fendo.2019.00424] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Accepted: 06/12/2019] [Indexed: 12/16/2022] Open
Abstract
Background: Disturbance of immunometabolic signaling is a key process involved in the progression of obesity. Microglia-the resident immune cells in the brain, initiate local immune responses. It is known that hypercaloric diets lead to microglial activation. Previously, we observed that hypothalamic microglial cells from mice fed high-fat diet (HFD) lose their day/night rhythm and are constantly activated. However, little is known about daily rhythmicity in microglial circadian, immune and metabolic functions, either in lean or obese conditions. Therefore, we hypothesized that HFD disturbs microglial immunometabolism in a day/night-dependent manner. Methods: Obesity was induced in Wistar rats by feeding them HFD ad libitum for the duration of 8 weeks. Microglia were isolated from HFD- and chow-fed control animals at six time points during 24 h [every 4 h starting 2 h after lights on, i.e., Zeitgeber Time 2 (ZT2)]. Gene expression was evaluated using quantitative RT-PCR. JTK_Cycle software was used to estimate daily rhythmicity. Statistical analysis was performed with two-way ANOVA test. Results: Consumption of the obesogenic diet resulted in a 40 g significantly higher body weight gain in week 8, compared to chow diet (p < 0.0001), associated with increased adiposity. We observed significant rhythmicity of circadian clock genes in microglia under chow conditions, which was partially lost in diet-induced obesity (DIO). Microglial immune gene expression also showed time-of-day differences, which were disrupted in HFD-fed animals. Microglia responded to the obesogenic conditions by a shift of substrate utilization with decreased glutamate and glucose metabolism in the active period of the animals, and an overall increase of lipid metabolism, as indicated by gene expression evaluation. Additionally, data on mitochondria bioenergetics and dynamics suggested an increased energy production in microglia during the inactive period on HFD. Finally, evaluation of monocyte functional gene expression showed small or absent effect of HFD on peripheral myeloid cells, suggesting a cell-specific microglial inflammatory response in DIO. Conclusions: An obesogenic diet affects microglial immunometabolism in a time-of-day dependent manner. Given the central role of the brain in energy metabolism, a better knowledge of daily rhythms in microglial immunometabolism could lead to a better understanding of the pathogenesis of obesity.
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Affiliation(s)
- Irina V. Milanova
- Department of Endocrinology and Metabolism, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, Netherlands
- Laboratory of Endocrinology, Amsterdam University Medical Center, Amsterdam Gastroenterology & Metabolism, University of Amsterdam, Amsterdam, Netherlands
| | - Martin J. T. Kalsbeek
- Department of Endocrinology and Metabolism, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, Netherlands
- Laboratory of Endocrinology, Amsterdam University Medical Center, Amsterdam Gastroenterology & Metabolism, University of Amsterdam, Amsterdam, Netherlands
| | - Xiao-Lan Wang
- Department of Endocrinology and Metabolism, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, Netherlands
- Laboratory of Endocrinology, Amsterdam University Medical Center, Amsterdam Gastroenterology & Metabolism, University of Amsterdam, Amsterdam, Netherlands
| | - Nikita L. Korpel
- Department of Endocrinology and Metabolism, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, Netherlands
- Laboratory of Endocrinology, Amsterdam University Medical Center, Amsterdam Gastroenterology & Metabolism, University of Amsterdam, Amsterdam, Netherlands
| | - Dirk Jan Stenvers
- Department of Endocrinology and Metabolism, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, Netherlands
- Laboratory of Endocrinology, Amsterdam University Medical Center, Amsterdam Gastroenterology & Metabolism, University of Amsterdam, Amsterdam, Netherlands
| | - Samantha E. C. Wolff
- Department of Endocrinology and Metabolism, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, Netherlands
- Laboratory of Endocrinology, Amsterdam University Medical Center, Amsterdam Gastroenterology & Metabolism, University of Amsterdam, Amsterdam, Netherlands
| | - Paul de Goede
- Department of Endocrinology and Metabolism, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, Netherlands
- Laboratory of Endocrinology, Amsterdam University Medical Center, Amsterdam Gastroenterology & Metabolism, University of Amsterdam, Amsterdam, Netherlands
| | - Annemieke C. Heijboer
- Laboratory of Endocrinology, Amsterdam University Medical Center, Amsterdam Gastroenterology & Metabolism, University of Amsterdam, Amsterdam, Netherlands
- Endocrine Laboratory, Department of Clinical Chemistry, Amsterdam University Medical Center, Amsterdam Gastroenterology & Metabolism, Vrije Universiteit Amsterdam, Amsterdam, Netherlands
| | - Eric Fliers
- Department of Endocrinology and Metabolism, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, Netherlands
- Laboratory of Endocrinology, Amsterdam University Medical Center, Amsterdam Gastroenterology & Metabolism, University of Amsterdam, Amsterdam, Netherlands
| | - Susanne E. la Fleur
- Department of Endocrinology and Metabolism, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, Netherlands
- Laboratory of Endocrinology, Amsterdam University Medical Center, Amsterdam Gastroenterology & Metabolism, University of Amsterdam, Amsterdam, Netherlands
- Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences, Amsterdam, Netherlands
| | - Andries Kalsbeek
- Department of Endocrinology and Metabolism, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, Netherlands
- Laboratory of Endocrinology, Amsterdam University Medical Center, Amsterdam Gastroenterology & Metabolism, University of Amsterdam, Amsterdam, Netherlands
- Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences, Amsterdam, Netherlands
| | - Chun-Xia Yi
- Department of Endocrinology and Metabolism, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, Netherlands
- Laboratory of Endocrinology, Amsterdam University Medical Center, Amsterdam Gastroenterology & Metabolism, University of Amsterdam, Amsterdam, Netherlands
- *Correspondence: Chun-Xia Yi
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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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Microglia derived from the axotomized adult rat facial nucleus uptake glutamate and metabolize it to glutamine in vitro. Neurochem Int 2016; 102:1-12. [PMID: 27816478 DOI: 10.1016/j.neuint.2016.10.015] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Revised: 09/12/2016] [Accepted: 10/31/2016] [Indexed: 11/22/2022]
Abstract
Microglia in the axotomized adult rat facial nucleus (axoFN) have been shown to highly express a glutamate transporter (GLT-1). The microglia appear to serve as glutamate (Glu) scavengers in the axoFN. However, there is no evidence that the microglia actually have the ability to uptake Glu and convert it to Gln. In this study, we investigated whether axoFN-derived microglia (axoFN-microglia) can uptake Glu and metabolize it to Gln. Microglia obtained by explant culture of axoFN on poly(N-isopropylacrylamide)-grafted dishes were non-invasively sub-cultured onto dishes or wells. Immunoblotting and Glu-uptake experiments revealed that the axoFN-microglia uptake 14C-Glu mainly by GLT-1 activity. Immunoblotting and immunocytochemical methods clarified that axoFN-microglia express the Gln synthetase (GS) protein in the same manner as newborn rat brain-derived primary microglia (NRB-microglia). Biochemical analysis demonstrated that the specific activity of GS of axoFN-microglia is similar to that of NRB-microglia, suggesting that these microglia play equivalent roles in the metabolic conversion of Glu to Gln. Nuclear magnetic resonance analysis clarified that NRB-microglia metabolize [13C]Glu to [13C]Gln depending on the incubation time, inferring the similar potential of axoFN-microglia. Taken together, these results demonstrate that axoFN-microglia express functional GLT-1 and GS proteins, and are strongly suggested to serve as Glu scavengers in vivo.
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Ackerman AL, Jellison FC, Lee UJ, Bradesi S, Rodríguez LV. The Glt1 glutamate receptor mediates the establishment and perpetuation of chronic visceral pain in an animal model of stress-induced bladder hyperalgesia. Am J Physiol Renal Physiol 2015; 310:F628-F636. [PMID: 26697981 DOI: 10.1152/ajprenal.00297.2015] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2015] [Accepted: 12/18/2015] [Indexed: 02/08/2023] Open
Abstract
Psychological stress exacerbates interstitial cystitis/bladder pain syndrome (IC/BPS), a lower urinary tract pain disorder characterized by increased urinary frequency and bladder pain. Glutamate (Glu) is the primary excitatory neurotransmitter modulating nociceptive networks. Glt1, an astrocytic transporter responsible for Glu clearance, is critical in pain signaling termination. We sought to examine the role of Glt1 in stress-induced bladder hyperalgesia and urinary frequency. In a model of stress-induced bladder hyperalgesia with high construct validity to human IC/BPS, female Wistar-Kyoto (WKY) rats were subjected to 10-day water avoidance stress (WAS). Referred hyperalgesia and tactile allodynia were assessed after WAS with von Frey filaments. After behavioral testing, we assessed Glt1 expression in the spinal cord by immunoblotting. We also examined the influence of dihydrokainate (DHK) and ceftriaxone (CTX), which downregulate and upregulate Glt1, respectively, on pain development. Rats exposed to WAS demonstrated increased voiding frequency, increased colonic motility, anxiety-like behaviors, and enhanced visceral hyperalgesia and tactile allodynia. This behavioral phenotype correlated with decreases in spinal Glt1 expression. Exogenous Glt1 downregulation by DHK resulted in hyperalgesia similar to that following WAS. Exogenous Glt1 upregulation via intraperitoneal CTX injection inhibited the development of and reversed preexisting pain and voiding dysfunction induced by WAS. Repeated psychological stress results in voiding dysfunction and hyperalgesia that correlate with altered central nervous system glutamate processing. Manipulation of Glu handling altered the allodynia developing after psychological stress, implicating Glu neurotransmission in the pathophysiology of bladder hyperalgesia in the WAS model of IC/BPS.
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Affiliation(s)
- A Lenore Ackerman
- Department of Urology, The David Geffen School of Medicine at UCLA, Los Angeles, California
| | - Forrest C Jellison
- Department of Urology, San Antonio Military Medical Center (SAMMC), Fort Sam Houston, Texas
| | - Una J Lee
- Section of Urology and Renal Transplantation, Virginia Mason Medical Center, Seattle, Washington
| | - Sylvie Bradesi
- Center for the Neurobiology of Stress, The David Geffen School of Medicine at UCLA, Los Angeles, California; and
| | - Larissa V Rodríguez
- Departments of Urology and Obstetrics and Gynecology, University of Southern California, Los Angeles, California
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15
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Yu D, Fan Y, Sun X, Yao L, Chai W. Effects of erythropoietin preconditioning on rat cerebral ischemia-reperfusion injury and the GLT-1/GLAST pathway. Exp Ther Med 2015; 11:513-518. [PMID: 26893639 DOI: 10.3892/etm.2015.2919] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2014] [Accepted: 05/12/2015] [Indexed: 01/17/2023] Open
Abstract
The aim of the present study was to investigate whether erythropoietin (EPO) preconditioning affects the expression of glutamate transporter 1 (GLT-1) and glutamate aspartate transporter (GLAST) and protects against rat cerebral ischemia-reperfusion injury. A total of 140 Sprague Dawley rats were randomly assigned to one of the following four groups: Sham, EPO-sham, middle cerebral artery occlusion (MCAO) and EPO-MCAO. Neurological function scores were obtained 24, 36 and 72 h after reperfusion. Seventy-two hours after the induction of cerebral ischemia-reperfusion, the number of apoptotic neural cells and the cerebral infarct volume of each group were measured. The mRNA levels of GLT-1 and GLAST were determined using reverse transcription-quantitative polymerase chain reaction (RT-qPCR) analysis, while the GLT-1 and GLAST protein levels were assessed using western blotting. The cerebral infarct volume was significantly increased in the MCAO group compared with that in the sham group (P<0.01); however, the infarct volume of the EPO-MCAO group was significantly lower than that of the MCAO group (P<0.01). In addition, the number of apoptotic cells found in the MCAO group was higher than that in the sham group (P<0.01), but the number of apoptotic cells in the EPO-MCAO group was significantly lower than that in the MCAO group (P<0.01). The GLT-1 and GLAST mRNA and protein levels were significantly decreased 72 h after the cerebral ischemia-reperfusion (P<0.01) compared with those in the sham group, whereas the same levels were increased significantly in the EPO-MCAO group relative to those in the MCAO group (P<0.01). In conclusion, EPO preconditioning protected against cerebral ischemia-reperfusion injury and upregulated the GLT-1 and GLAST expression.
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Affiliation(s)
- Daihua Yu
- Department of Anesthesiology, Tangdu Hospital of the Fourth Military Medical University, Xi'an, Shanxi 710000, P.R. China
| | - Yuanhua Fan
- Intensive Care Unit, Ganzhou People Hospital, Nanchang University, Ganzhou, Jiangxi 325000, P.R. China
| | - Xude Sun
- Department of Anesthesiology, Tangdu Hospital of the Fourth Military Medical University, Xi'an, Shanxi 710000, P.R. China
| | - Linong Yao
- Department of Anesthesiology, Tangdu Hospital of the Fourth Military Medical University, Xi'an, Shanxi 710000, P.R. China
| | - Wei Chai
- Department of Anesthesiology, Tangdu Hospital of the Fourth Military Medical University, Xi'an, Shanxi 710000, P.R. China
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Murakami G, Nakamura M, Takita M, Ishida Y, Ueki T, Nakahara D. Brain Rewarding Stimulation Reduces Extracellular Glutamate Through Glial Modulation in Medial Prefrontal Cortex of Rats. Neuropsychopharmacology 2015; 40:2686-95. [PMID: 25924203 PMCID: PMC4864644 DOI: 10.1038/npp.2015.115] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/15/2014] [Revised: 03/16/2015] [Accepted: 03/24/2015] [Indexed: 12/29/2022]
Abstract
Growing evidence implicates a critical involvement of prefrontal glial modulation of extracellular glutamate (GLU) in aversive behaviors. However, nothing is known about whether prefrontal glial cells modulate GLU levels in rewarding behaviors. To address this question, we measured GLU efflux in the medial prefrontal cortex (PFC) of rats associated with rewarding behaviors. We used intracranial self-stimulation (ICSS) of the medial forebrain bundle (MFB) as the rewarding behavior. GLU was indirectly measured using microdialysis combined with on-line fluorometric detection of NADH resulting from the reaction of GLU and NAD(+) catalyzed by GLU dehydrogenase with a time resolution of 1 min. ICSS caused a minute-by-minute change of extracellular GLU in the medial PFC, with a slight decrease during the stimulation, followed by an increase afterward. This bidirectional change was tetrodotoxin insensitive and abolished by the gliotoxin fluorocitrate. To confirm and extend the previous studies of aversion-induced increase of extracellular GLU in the medial PFC, we also measured prefrontal GLU efflux associated with an aversive stimulation, immobilization stress. The temporal change in extracellular GLU caused by this stress was markedly different from that observed during ICSS. A rapid increase in GLU was detected during the aversive stimulation, followed by a large increase afterward. This bimodal change was tetrodotoxin insensitive, similar to that detected for ICSS. These findings indicate a bidirectional regulation of extracellular GLU by prefrontal glial cells associated with rat ICSS behavior, and reveal that glial modulation of GLU neurochemistry in the medial PFC contributes to rewarding as well as aversive behaviors in rats.
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Affiliation(s)
- Gen Murakami
- Division of Psychology and Behavioral Neuroscience, Department of Integrated Human Sciences, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Masato Nakamura
- Division of Psychology and Behavioral Neuroscience, Department of Integrated Human Sciences, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Masatoshi Takita
- Cognition and Action Research Group, National Institute of Advanced Industrial Science and Technology, Tsukuba, Japan
| | - Yasushi Ishida
- Department of Psychiatry, Faculty of Medicine, University of Miyazaki, Miyazaki, Japan
| | - Takatoshi Ueki
- Department of Anatomy and Cell Biology, Graduate School of Medical Sciences, Nagoya City University, Nagoya, Japan
- Department of Biofunctional Imaging, Medical Photonics Center, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Daiichiro Nakahara
- Division of Psychology and Behavioral Neuroscience, Department of Integrated Human Sciences, Hamamatsu University School of Medicine, Hamamatsu, Japan
- Department of Biofunctional Imaging, Medical Photonics Center, Hamamatsu University School of Medicine, Hamamatsu, Japan
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Morara S, Colangelo AM, Provini L. Microglia-Induced Maladaptive Plasticity Can Be Modulated by Neuropeptides In Vivo. Neural Plast 2015; 2015:135342. [PMID: 26273481 PMCID: PMC4529944 DOI: 10.1155/2015/135342] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Accepted: 06/25/2015] [Indexed: 02/06/2023] Open
Abstract
Microglia-induced maladaptive plasticity is being recognized as a major cause of deleterious self-sustaining pathological processes that occur in neurodegenerative and neuroinflammatory diseases. Microglia, the primary homeostatic guardian of the central nervous system, exert critical functions both during development, in neural circuit reshaping, and during adult life, in the brain physiological and pathological surveillance. This delicate critical role can be disrupted by neural, but also peripheral, noxious stimuli that can prime microglia to become overreactive to a second noxious stimulus or worsen underlying pathological processes. Among regulators of microglia, neuropeptides can play a major role. Their receptors are widely expressed in microglial cells and neuropeptide challenge can potently influence microglial activity in vitro. More relevantly, this regulator activity has been assessed also in vivo, in experimental models of brain diseases. Neuropeptide action in the central nervous system has been associated with beneficial effects in neurodegenerative and neuroinflammatory pathological experimental models. This review describes some of the mechanisms of the microglia maladaptive plasticity in vivo and how neuropeptide activity can represent a useful therapeutical target in a variety of human brain pathologies.
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Affiliation(s)
- Stefano Morara
- Neuroscience Institute (CNR), Via Vanvitelli 32, 20129 Milano, Italy
- Department of BIOMETRA, University of Milano, Via Vanvitelli 32, 20129 Milano, Italy
| | - Anna Maria Colangelo
- Laboratory of Neuroscience “R. Levi-Montalcini”, Department of Biotechnology and Biosciences, University of Milano-Bicocca, Piazza della Scienza 2, 20126 Milano, Italy
- SYSBIO Centre of Systems Biology, University of Milano-Bicocca, Piazza della Scienza 2, 20126 Milano, Italy
- NeuroMI Milan Center for Neuroscience, University of Milano-Bicocca, 20126 Milano, Italy
| | - Luciano Provini
- Department of BIOMETRA, University of Milano, Via Vanvitelli 32, 20129 Milano, Italy
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Intracellular redistribution of acetyl-CoA, the pivotal point in differential susceptibility of cholinergic neurons and glial cells to neurodegenerative signals. Biochem Soc Trans 2015; 42:1101-6. [PMID: 25110009 DOI: 10.1042/bst20140078] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Intramitochondrial decarboxylation of glucose-derived pyruvate by PDHC (pyruvate dehydrogenase complex) is a principal source of acetyl-CoA, for mitochondrial energy production and cytoplasmic synthetic pathways in all types of brain cells. The inhibition of PDHC, ACO (aconitase) and KDHC (ketoglutarate dehydrogenase complex) activities by neurodegenerative signals such as aluminium, zinc, amyloid β-peptide, excess nitric oxide (NO) or thiamine pyrophosphate deficits resulted in much deeper losses of viability, acetyl-CoA and ATP in differentiated cholinergic neuronal cells than in non-differentiated cholinergic, and cultured microglial or astroglial cell lines. In addition, in cholinergic cells, such conditions caused inhibition of ACh (acetylcholine) synthesis and its quantal release. Furthermore, cholinergic neuronal cells appeared to be resistant to high concentrations of LPS (lipopolysaccharide). In contrast, in microglial cells, low levels of LPS caused severalfold activation of NO, IL-6 (interleukin 6) and TNFα (tumour necrosis factor α) synthesis/release, accompanied by inhibition of PDHC, KDHC and ACO activities, and suppression of acetyl-CoA, but relatively small losses in their ATP contents and viability parameters. Compounds that protected these enzymes against inhibitory effects of neurotoxins alleviated acetyl-CoA and ATP deficits, thereby maintaining neuronal cell viability. These data indicate that preferential susceptibility of cholinergic neurons to neurodegenerative insults may result from competition for acetyl-CoA between mitochondrial energy-producing and cytoplasmic ACh-synthesizing pathways. Such a hypothesis is supported by the existence of highly significant correlations between mitochondrial/cytoplasmic acetyl-CoA levels and cell viability/transmitter functions respectively.
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Resveratrol downregulates type-1 glutamate transporter expression and microglia activation in the hippocampus following cerebral ischemia reperfusion in rats. Brain Res 2015; 1608:203-14. [DOI: 10.1016/j.brainres.2015.02.038] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2014] [Revised: 02/17/2015] [Accepted: 02/18/2015] [Indexed: 01/04/2023]
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Antagonism of PACAP or microglia function worsens the cardiovascular consequences of kainic-acid-induced seizures in rats. J Neurosci 2015; 35:2191-9. [PMID: 25653374 DOI: 10.1523/jneurosci.4058-14.2015] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Seizures are accompanied by cardiovascular changes that are a major cause of sudden unexpected death in epilepsy (SUDEP). Seizures activate inflammatory responses in the cardiovascular nuclei of the medulla oblongata and increase neuronal excitability. Pituitary adenylate cyclase-activating polypeptide (PACAP) is a neuropeptide with autocrine and paracrine neuroprotective properties. Microglia are key players in inflammatory responses in the CNS. We sought to determine whether PACAP and microglia mitigate the adverse effects of seizure on cardiovascular function in a rat model of temporal lobe epilepsy. Kainic acid (KA)-induced seizures increased splanchnic sympathetic nerve activity by 97%, accompanied by increase in heart rate (HR) but not blood pressure (BP). Intrathecal infusion of the PACAP antagonist PACAP(6-38) or the microglia antagonists minocycline and doxycycline augmented sympathetic responses to KA-induced seizures. PACAP(6-38) caused a 161% increase, whereas minocycline and doxycycline caused a 225% and 215% increase, respectively. In intrathecal PACAP-antagonist-treated rats, both BP and HR increased, whereas after treatment with microglial antagonists, only BP was significantly increased compared with control. Our findings support the idea that PACAP and its action on microglia at the level of the spinal cord elicit cardioprotective effects during seizure. However, intrathecal PACAP did not show additive effects, suggesting that the agonist effect was at maximum. The protective effect of microglia may occur by adoption of an M2 phenotype and expression of factors such as TGF-β and IL-10 that promote neuronal quiescence. In summary, therapeutic interventions targeting PACAP and microglia could be a promising strategy for preventing SUDEP.
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Klimaszewska-Łata J, Gul-Hinc S, Bielarczyk H, Ronowska A, Zyśk M, Grużewska K, Pawełczyk T, Szutowicz A. Differential effects of lipopolysaccharide on energy metabolism in murine microglial N9 and cholinergic SN56 neuronal cells. J Neurochem 2015; 133:284-97. [PMID: 25345568 DOI: 10.1111/jnc.12979] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2014] [Revised: 10/10/2014] [Accepted: 10/13/2014] [Indexed: 12/27/2022]
Abstract
There are significant differences between acetyl-CoA and ATP levels, enzymes of acetyl-CoA metabolism, and toll-like receptor 4 contents in non-activated microglial N9 and non-differentiated cholinergic SN56 neuroblastoma cells. Exposition of N9 cells to lipopolysaccharide caused concentration-dependent several-fold increases of nitrogen oxide synthesis, accompanied by inhibition of pyruvate dehydrogenase complex, aconitase, and α-ketoglutarate dehydrogenase complex activities, and by nearly proportional depletion of acetyl-CoA, but by relatively smaller losses in ATP content and cell viability (about 5%). On the contrary, SN56 cells appeared to be insensitive to direct exposition to high concentration of lipopolysaccharide. However, exogenous nitric oxide resulted in marked inhibition pyruvate dehydrogenase and aconitase activities, depletion of acetyl-CoA, along with respective loss of SN56 cells viability. These data indicate that these two common neurodegenerative signals may differentially affect energy-acetyl-CoA metabolism in microglial and cholinergic neuronal cell compartments in the brain. Moreover, microglial cells appeared to be more resistant than neuronal cells to acetyl-CoA and ATP depletion evoked by these neurodegenerative conditions. Together, these data indicate that differential susceptibility of microglia and cholinergic neuronal cells to neurotoxic signals may result from differences in densities of toll-like receptors and degree of disequilibrium between acetyl-CoA provision in mitochondria and its utilization for energy production and acetylation reactions in each particular group of cells. There are significant differences between acetyl-CoA and ATP levels and enzymes of acetyl-CoA metabolism in non-activated microglial N9 and non-differentiated cholinergic SN56 neuroblastoma cells. Pathological stimulation of microglial toll-like receptors (TLRs) triggered excessive synthesis of microglia-derived nitric oxide (NO)/NOO radicals that endogenously inhibited pyruvate dehydrogenase complex (PDHC), aconitase, and α-ketoglutarate dehydrogenase complex. However, it caused none or small suppressions of acetyl-CoA and microglial viability, respectively. Microglia-derived NO inhibited same enzymes in cholinergic neuronal cells causing marked viability loss because of acetyl-CoA deficits evoked by its competitive consumption by energy producing and acetylcholine/N-acetyl-l-aspartate (NAA) synthesizing pathways.
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22
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Rojo AI, McBean G, Cindric M, Egea J, López MG, Rada P, Zarkovic N, Cuadrado A. Redox control of microglial function: molecular mechanisms and functional significance. Antioxid Redox Signal 2014; 21:1766-801. [PMID: 24597893 PMCID: PMC4186766 DOI: 10.1089/ars.2013.5745] [Citation(s) in RCA: 234] [Impact Index Per Article: 23.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Neurodegenerative diseases are characterized by chronic microglial over-activation and oxidative stress. It is now beginning to be recognized that reactive oxygen species (ROS) produced by either microglia or the surrounding environment not only impact neurons but also modulate microglial activity. In this review, we first analyze the hallmarks of pro-inflammatory and anti-inflammatory phenotypes of microglia and their regulation by ROS. Then, we consider the production of reactive oxygen and nitrogen species by NADPH oxidases and nitric oxide synthases and the new findings that also indicate an essential role of glutathione (γ-glutamyl-l-cysteinylglycine) in redox homeostasis of microglia. The effect of oxidant modification of macromolecules on signaling is analyzed at the level of oxidized lipid by-products and sulfhydryl modification of microglial proteins. Redox signaling has a profound impact on two transcription factors that modulate microglial fate, nuclear factor kappa-light-chain-enhancer of activated B cells, and nuclear factor (erythroid-derived 2)-like 2, master regulators of the pro-inflammatory and antioxidant responses of microglia, respectively. The relevance of these proteins in the modulation of microglial activity and the interplay between them will be evaluated. Finally, the relevance of ROS in altering blood brain barrier permeability is discussed. Recent examples of the importance of these findings in the onset or progression of neurodegenerative diseases are also discussed. This review should provide a profound insight into the role of redox homeostasis in microglial activity and help in the identification of new promising targets to control neuroinflammation through redox control of the brain.
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Affiliation(s)
- Ana I Rojo
- 1 Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED) , Madrid, Spain
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Terashima T, Kojima H, Urabe H, Yamakawa I, Ogawa N, Kawai H, Chan L, Maegawa H. Stem cell factor-activated bone marrow ameliorates amyotrophic lateral sclerosis by promoting protective microglial migration. J Neurosci Res 2014; 92:856-69. [PMID: 24936617 PMCID: PMC4061499 DOI: 10.1002/jnr.23368] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) is a progressive disease associated with motor neuron death. Several experimental treatments, including cell therapy using hematopoietic or neuronal stem cells, have been tested in ALS animal models, but therapeutic benefits have been modest. Here we used a new therapeutic strategy, bone marrow transplantation (BMT) with stem cell factor (SCF)- or FMS-like tyrosine kinase 3 (flt3)-activated bone marrow (BM) cells for the treatment of hSOD1(G93A) transgenic mice. Motor function and survival showed greater improvement in the SCF group than in the group receiving BM cells that had not been activated (BMT alone group), although no improvement was shown in the flt3 group. In addition, larger numbers of BM-derived cells that expressed the microglia marker Iba1 migrated to the spinal cords of recipient mice compared with the BMT alone group. Moreover, after SCF activation, but not flt3 activation or no activation, the migrating microglia expressed glutamate transporter-1 (GLT-1). In spinal cords in the SCF group, inflammatory cytokines tumor necrosis factor-α and interleukin-1β were suppressed and the neuroprotective molecule insulin-like growth factor-1 increased relative to nontreatment hSOD1(G93A) transgenic mice. Therefore, SCF activation changed the character of the migrating donor BM cells, which resulted in neuroprotective effects. These studies have identified SCF-activated BM cells as a potential new therapeutic agent for the treatment of ALS.
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Affiliation(s)
- Tomoya Terashima
- Department of Medicine, Shiga University of Medical Science, Seta, Otsu, Shiga, Japan
| | - Hideto Kojima
- Stem Cell Biology and Regenerative Medicine, Shiga University of Medical Science, Seta, Otsu, Shiga, Japan
| | - Hiroshi Urabe
- Department of Medicine, Shiga University of Medical Science, Seta, Otsu, Shiga, Japan
| | - Isamu Yamakawa
- Department of Medicine, Shiga University of Medical Science, Seta, Otsu, Shiga, Japan
| | - Nobuhiro Ogawa
- Department of Medicine, Shiga University of Medical Science, Seta, Otsu, Shiga, Japan
| | - Hiromichi Kawai
- Department of Medicine, Shiga University of Medical Science, Seta, Otsu, Shiga, Japan
| | - Lawrence Chan
- Departments of Medicine and Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas
| | - Hiroshi Maegawa
- Department of Medicine, Shiga University of Medical Science, Seta, Otsu, Shiga, Japan
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Eisenkraft A, Falk A, Finkelstein A. The role of glutamate and the immune system in organophosphate-induced CNS damage. Neurotox Res 2013; 24:265-79. [PMID: 23532600 DOI: 10.1007/s12640-013-9388-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2013] [Revised: 03/10/2013] [Accepted: 03/15/2013] [Indexed: 12/12/2022]
Abstract
Organophosphate (OP) poisoning is associated with long-lasting neurological damage, which is attributed mainly to the excessive levels of glutamate caused by the intoxication. Glutamate toxicity, however, is not specific to OP poisoning, and is linked to propagation of damage in both acute and chronic neurodegenerative conditions in the central nervous system (CNS). In addition to acute excitotoxic effects of glutamate, there is now a growing amount of evidence of its intricate immunomodulatory effects in the brain, involving both the innate and the adaptive immune systems. Moreover, it was demonstrated that immunomodulatory treatments, aimed at regulating the interaction between the resident immune cells of the brain (microglia) and the peripheral immune system, can support buffering of excessive levels of glutamate and restoration of the homeostasis. In this review, we will discuss the role of glutamate as an excitotoxic agent in the acute phase of OP poisoning, and the possible functions it may have as both a neuroprotectant and an immunomodulator in the sub-acute and chronic phases of OP poisoning. In addition, we will describe the novel immune-based neuroprotective strategies aimed at counteracting the long-term neurodegenerative effects of glutamate in the CNS.
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25
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Wong WT. Microglial aging in the healthy CNS: phenotypes, drivers, and rejuvenation. Front Cell Neurosci 2013; 7:22. [PMID: 23493481 PMCID: PMC3595516 DOI: 10.3389/fncel.2013.00022] [Citation(s) in RCA: 157] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2012] [Accepted: 02/21/2013] [Indexed: 12/12/2022] Open
Abstract
Neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease, and age-related macular degeneration (AMD), share two characteristics in common: (1) a disease prevalence that increases markedly with advancing age, and (2) neuroinflammatory changes in which microglia, the primary resident immune cell of the CNS, feature prominently. These characteristics have led to the hypothesis that pathogenic mechanisms underlying age-related neurodegenerative disease involve aging changes in microglia. If correct, targeting features of microglial senescence may constitute a feasible therapeutic strategy. This review explores this hypothesis and its implications by considering the current knowledge on how microglia undergo change during aging and how the emergence of these aging phenotypes relate to significant alterations in microglial function. Evidence and theories on cellular mechanisms implicated in driving senescence in microglia are reviewed, as are “rejuvenative” measures and strategies that aim to reverse or ameliorate the aging microglial phenotype. Understanding and controlling microglial aging may represent an opportunity for elucidating disease mechanisms and for formulating novel therapies.
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Affiliation(s)
- Wai T Wong
- Unit on Neuron-Glia Interactions in Retinal Disease, National Eye Institute, National Institutes of Health Bethesda, MD, USA
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26
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Neuroprotective properties of the excitatory amino acid carrier 1 (EAAC1). Amino Acids 2013; 45:133-42. [PMID: 23462929 DOI: 10.1007/s00726-013-1481-5] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Accepted: 02/23/2013] [Indexed: 01/09/2023]
Abstract
Extracellular glutamate should be maintained at low levels to conserve optimal neurotransmission and prevent glutamate neurotoxicity in the brain. Excitatory amino acid transporters (EAATs) play a pivotal role in removing extracellular glutamate in the central nervous system (CNS). Excitatory amino acid carrier 1 (EAAC1) is a high-affinity Na⁺-dependent neuronal EAAT that is ubiquitously expressed in the brain. However, most glutamate released in the synapses is cleared by glial EAATs, but not by EAAC1 in vivo. In the CNS, EAAC1 is widely distributed in somata and dendrites but not in synaptic terminals. The contribution of EAAC1 to the control of extracellular glutamate levels seems to be negligible in the brain. However, EAAC1 can transport not only extracellular glutamate but also cysteine into the neurons. Cysteine is an important substrate for glutathione (GSH) synthesis in the brain. GSH has a variety of neuroprotective functions, while its depletion induces neurodegeneration. Therefore, EAAC1 might exert a critical role for neuroprotection in neuronal GSH metabolism rather than glutamatergic neurotransmission, while EAAC1 dysfunction would cause neurodegeneration. Despite the potential importance of EAAC1 in the brain, previous studies have mainly focused on the glutamate neurotoxicity induced by glial EAAT dysfunction. In recent years, however, several studies have revealed regulatory mechanisms of EAAC1 functions in the brain. This review will summarize the latest information on the EAAC1-regulated neuroprotective functions in the CNS.
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Ishikawa M. Abnormalities in glutamate metabolism and excitotoxicity in the retinal diseases. SCIENTIFICA 2013; 2013:528940. [PMID: 24386591 PMCID: PMC3872404 DOI: 10.1155/2013/528940] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2013] [Accepted: 11/17/2013] [Indexed: 05/14/2023]
Abstract
In the physiological condition, glutamate acts as an excitatory neurotransmitter in the retina. However, excessive glutamate can be toxic to retinal neurons by overstimulation of the glutamate receptors. Glutamate excess is primarily attributed to perturbation in the homeostasis of the glutamate metabolism. Major pathway of glutamate metabolism consists of glutamate uptake by glutamate transporters followed by enzymatic conversion of glutamate to nontoxic glutamine by glutamine synthetase. Glutamate metabolism requires energy supply, and the energy loss inhibits the functions of both glutamate transporters and glutamine synthetase. In this review, we describe the present knowledge concerning the retinal glutamate metabolism under the physiological and pathological conditions.
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Affiliation(s)
- Makoto Ishikawa
- Department of Ophthalmology, Akita Graduate University Faculty of Medicine, 1-1-1 Hondo, Akita 010-8543, Japan
- *Makoto Ishikawa:
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28
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Abstract
Dysregulation of glutathione homeostasis and alterations in glutathione-dependent enzyme activities are increasingly implicated in the induction and progression of neurodegenerative diseases, including Alzheimer’s, Parkinson’s and Huntington’s diseases, amyotrophic lateral sclerosis, and Friedreich’s ataxia. In this review background is provided on the steady-state synthesis, regulation, and transport of glutathione, with primary focus on the brain. A brief overview is presented on the distinct but vital roles of glutathione in cellular maintenance and survival, and on the functions of key glutathione-dependent enzymes. Major contributors to initiation and progression of neurodegenerative diseases are considered, including oxidative stress, protein misfolding, and protein aggregation. In each case examples of key regulatory mechanisms are identified that are sensitive to changes in glutathione redox status and/or in the activities of glutathione-dependent enzymes. Mechanisms of dysregulation of glutathione and/or glutathione-dependent enzymes are discussed that are implicated in pathogenesis of each neurodegenerative disease. Limitations in information or interpretation are identified, and possible avenues for further research are described with an aim to elucidating novel targets for therapeutic interventions. The pros and cons of administration of N-acetylcysteine or glutathione as therapeutic agents for neurodegenerative diseases, as well as the potential utility of serum glutathione as a biomarker, are critically evaluated.
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Riluzole-triggered GSH synthesis via activation of glutamate transporters to antagonize methylmercury-induced oxidative stress in rat cerebral cortex. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2012; 2012:534705. [PMID: 22966415 PMCID: PMC3432391 DOI: 10.1155/2012/534705] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/10/2012] [Revised: 06/25/2012] [Accepted: 07/08/2012] [Indexed: 11/18/2022]
Abstract
OBJECTIVE This study was to evaluate the effect of riluzole on methylmercury- (MeHg-) induced oxidative stress, through promotion of glutathione (GSH) synthesis by activating of glutamate transporters (GluTs) in rat cerebral cortex. METHODS Eighty rats were randomly assigned to four groups, control group, riluzole alone group, MeHg alone group, and riluzole + MeHg group. The neurotoxicity of MeHg was observed by measuring mercury (Hg) absorption, pathological changes, and cell apoptosis of cortex. Oxidative stress was evaluated via determining reactive oxygen species (ROS), 8-hydroxy-2-deoxyguanosine (8-OHdG), malondialdehyde (MDAs), carbonyl, sulfydryl, and GSH in cortex. Glutamate (Glu) transport was studied by measuring Glu, glutamine (Gln), mRNA, and protein of glutamate/aspartate transporter (GLAST) and glutamate transporter-1 (GLT-1). RESULT (1) MeHg induced Hg accumulation, pathological injury, and apoptosis of cortex; (2) MeHg increased ROS, 8-OHdG, MDA, and carbonyl, and inhibited sulfydryl and GSH; (3) MeHg elevated Glu, decreased Gln, and downregulated GLAST and GLT-1 mRNA expression and protein levels; (4) riluzole antagonized MeHg-induced downregulation of GLAST and GLT-1 function and expression, GSH depletion, oxidative stress, pathological injury, and apoptosis obviously. CONCLUSION Data indicate that MeHg administration induced oxidative stress in cortex and that riluzole could antagonize this situation through elevation of GSH synthesis by activating of GluTs.
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Conrad M, Sato H. The oxidative stress-inducible cystine/glutamate antiporter, system x (c) (-) : cystine supplier and beyond. Amino Acids 2011; 42:231-46. [PMID: 21409388 DOI: 10.1007/s00726-011-0867-5] [Citation(s) in RCA: 411] [Impact Index Per Article: 31.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2010] [Accepted: 02/17/2011] [Indexed: 12/17/2022]
Abstract
The oxidative stress-inducible cystine/glutamate exchange system, system x (c) (-) , transports one molecule of cystine, the oxidized form of cysteine, into cells and thereby releases one molecule of glutamate into the extracellular space. It consists of two protein components, the 4F2 heavy chain, necessary for membrane location of the heterodimer, and the xCT protein, responsible for transport activity. Previously, system x (c) (-) has been regarded to be a mere supplier of cysteine to cells for the synthesis of proteins and the antioxidant glutathione (GSH). In that sense, oxygen, electrophilic agents, and bacterial lipopolysaccharide trigger xCT expression to accommodate with increased oxidative stress by stimulating GSH biosynthesis. However, emerging evidence established that system x (c) (-) may act on its own as a GSH-independent redox system by sustaining a redox cycle over the plasma membrane. Hallmarks of this cycle are cystine uptake, intracellular reduction to cysteine and secretion of the surplus of cysteine into the extracellular space. Consequently, increased levels of extracellular cysteine provide a reducing microenvironment required for proper cell signaling and communication, e.g. as already shown for the mechanism of T cell activation. By contrast, the enhanced release of glutamate in exchange with cystine may trigger neurodegeneration due to glutamate-induced cytotoxic processes. This review aims to provide a comprehensive picture from the early days of system x (c) (-) research up to now.
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Affiliation(s)
- Marcus Conrad
- DZNE, German Center for Neurodegenerative Diseases, Munich, 80336, Munich, Germany.
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31
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Had-Aissouni L. Toward a new role for plasma membrane sodium-dependent glutamate transporters of astrocytes: maintenance of antioxidant defenses beyond extracellular glutamate clearance. Amino Acids 2011; 42:181-97. [DOI: 10.1007/s00726-011-0863-9] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2010] [Accepted: 02/17/2011] [Indexed: 01/17/2023]
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32
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Had-Aissouni L. Maintenance of antioxidant defenses of brain cells: plasma membrane glutamate transporters and beyond. Amino Acids 2011; 42:159-61. [DOI: 10.1007/s00726-011-0860-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2010] [Accepted: 02/17/2011] [Indexed: 01/17/2023]
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Aoyama K, Watabe M, Nakaki T. Modulation of neuronal glutathione synthesis by EAAC1 and its interacting protein GTRAP3-18. Amino Acids 2011; 42:163-9. [PMID: 21373771 DOI: 10.1007/s00726-011-0861-y] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2010] [Accepted: 02/17/2011] [Indexed: 01/17/2023]
Abstract
Glutathione (GSH) plays essential roles in different processes such as antioxidant defenses, cell signaling, cell proliferation, and apoptosis in the central nervous system. GSH is a tripeptide composed of glutamate, cysteine, and glycine. The concentration of cysteine in neurons is much lower than that of glutamate or glycine, so that cysteine is the rate-limiting substrate for neuronal GSH synthesis. Most neuronal cysteine uptake is mediated through the neuronal sodium-dependent glutamate transporter, known as excitatory amino acid carrier 1 (EAAC1). Glutamate transporters are vulnerable to oxidative stress and EAAC1 dysfunction impairs neuronal GSH synthesis by reducing cysteine uptake. This may start a vicious circle leading to neurodegeneration. Intracellular signaling molecules functionally regulate EAAC1. Glutamate transporter-associated protein 3-18 (GTRAP3-18) activation down-regulates EAAC1 function. Here, we focused on the interaction between EAAC1 and GTRAP3-18 at the plasma membrane to investigate their effects on neuronal GSH synthesis. Increased level of GTRAP3-18 protein induced a decrease in GSH level and, thereby, increased the vulnerability to oxidative stress, while decreased level of GTRAP3-18 protein induced an increase in GSH level in vitro. We also confirmed these results in vivo. Our studies demonstrate that GTRAP3-18 regulates neuronal GSH level by controlling the EAAC1-mediated uptake of cysteine.
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Affiliation(s)
- Koji Aoyama
- Department of Pharmacology, Teikyo University School of Medicine, 2-11-1 Kaga, Itabashi, Tokyo, 173-8605, Japan
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