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Vázquez-Durán DL, Ortega A, Rodríguez A. Amino Acid Transporters Proteins Involved in the Glutamate-Glutamine Cycle and Their Alterations in Murine Models of Alzheimer's Disease. Mol Neurobiol 2024:10.1007/s12035-024-03966-3. [PMID: 38273046 DOI: 10.1007/s12035-024-03966-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2023] [Accepted: 01/16/2024] [Indexed: 01/27/2024]
Abstract
The brain's ability to integrate external stimuli and generate responses is highly complex. While these mechanisms are not completely understood, current evidence suggests that alterations in cellular metabolism and microenvironment are involved in some dysfunctions as complex as Alzheimer's disease. This pathology courses with defects in the establishment of chemical synapses, which is dependent on the production and supply of neurotransmitters like glutamate and its recycling through the glutamate-glutamine cycle. Alterations in the expression and function of the amino acid transporters proteins involved in this cycle have recently been reported in different stages of Alzheimer's disease. Most of these data come from patients in advanced stages of the disease or post-mortem, due to the ethical and technical limitations of human studies. Therefore, genetically modified mouse models have been an excellent tool to analyze metabolic and even behavioral parameters that are very similar to those that develop in Alzheimer's disease, even at presymptomatic stages. Hence, this paper analyzes the role of glutamate metabolism and its intercellular trafficking in excitatory synapses from different approaches using transgenic mouse models; such an analysis will contribute to our present understanding of AD.
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Affiliation(s)
| | - Arturo Ortega
- Departamento de Toxicología, Cinvestav- IPN, Mexico City, México
| | - Angelina Rodríguez
- Facultad de Ciencias Naturales, Universidad Autónoma de Querétaro, Santiago de Querétaro, México.
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2
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Ji Y, Wang L, Ding H, Tian Q, Fan K, Shi D, Yu C, Qin W. Aberrant neurovascular coupling in Leber's hereditary optic neuropathy: Evidence from a multi-model MRI analysis. Front Neurosci 2023; 16:1050772. [PMID: 36703998 PMCID: PMC9871937 DOI: 10.3389/fnins.2022.1050772] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Accepted: 12/22/2022] [Indexed: 01/12/2023] Open
Abstract
The study aimed to investigate the neurovascular coupling abnormalities in Leber's hereditary optic neuropathy (LHON) and their associations with clinical manifestations. Twenty qualified acute Leber's hereditary optic neuropathy (A-LHON, disease duration ≤ 1 year), 29 chronic Leber's hereditary optic neuropathy (C-LHON, disease duration > 1 year), as well as 37 healthy controls (HCs) were recruited. The neurovascular coupling strength was quantified as the ratio between regional homogeneity (ReHo), which represents intrinsic neuronal activity and relative cerebral blood flow (CBF), representing microcirculatory blood supply. A one-way analysis of variance was used to compare intergroup differences in ReHo/CBF ratio with gender and age as co-variables. Pearson's Correlation was used to clarify the association between ReHo, CBF, and neurovascular coupling strength. Furthermore, we applied linear and exponential non-linear regression models to explore the associations among ReHo/CBF, disease duration, and neuro-ophthalmological metrics. Compared with HCs, A_LHON, and C_LHON patients demonstrated a higher ReHo/CBF ratio than the HCs in the bilateral primary visual cortex (B_CAL), which was accompanied by reduced CBF while preserved ReHo. Besides, only C_LHON had a higher ReHo/CBF ratio and reduced CBF in the left middle temporal gyrus (L_MTG) and left sensorimotor cortex (L_SMC) than the HCs, which was accompanied by increased ReHo in L_MTG (p < 1.85e-3, Bonferroni correction). A-LHON and C-LHON showed a negative Pearson correlation between ReHo/CBF ratio and CBF in B_CAL, L_SMC, and L_MTG. Only C_LHON showed a weak positive correlation between ReHo/CBF ratio and ReHo in L_SMC and L_MTG (p < 0.05, uncorrected). Finally, disease duration was positively correlated with ReHo/CBF ratio of L_SMC (Exponential: Radj2 = 0.23, p = 8.66e-4, Bonferroni correction). No statistical correlation was found between ReHo/CBF ratio and neuro-ophthalmological metrics (p > 0.05, Bonferroni correction). Brain neurovascular "dyscoupling" within and outside the visual system might be an important neurological mechanism of LHON.
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Affiliation(s)
- Yi Ji
- Tianjin Key Lab of Functional Imaging, Department of Radiology, Tianjin Medical University General Hospital, Tianjin, China
| | - Ling Wang
- Department of Medical Imaging, Henan Provincial People’s Hospital, Zhengzhou, China
| | - Hao Ding
- Tianjin Key Lab of Functional Imaging, Department of Radiology, Tianjin Medical University General Hospital, Tianjin, China,School of Medical Imaging, Tianjin Medical University, Tianjin, China
| | - Qin Tian
- Department of Medical Imaging, Henan Provincial People’s Hospital, Zhengzhou, China
| | - Ke Fan
- Henan Eye Institute, Henan Eye Hospital, Henan Provincial People’s Hospital, Zhengzhou University People’s Hospital, Zhengzhou, China
| | - Dapeng Shi
- Department of Medical Imaging, Henan Provincial People’s Hospital, Zhengzhou, China,*Correspondence: Dapeng Shi,
| | - Chunshui Yu
- Tianjin Key Lab of Functional Imaging, Department of Radiology, Tianjin Medical University General Hospital, Tianjin, China,Chunshui Yu,
| | - Wen Qin
- Tianjin Key Lab of Functional Imaging, Department of Radiology, Tianjin Medical University General Hospital, Tianjin, China,Wen Qin,
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Roy P, Tomassoni D, Nittari G, Traini E, Amenta F. Effects of choline containing phospholipids on the neurovascular unit: A review. Front Cell Neurosci 2022; 16:988759. [PMID: 36212684 PMCID: PMC9541750 DOI: 10.3389/fncel.2022.988759] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Accepted: 08/22/2022] [Indexed: 11/13/2022] Open
Abstract
The roles of choline and of choline-containing phospholipids (CCPLs) on the maintenance and progress of neurovascular unit (NVU) integrity are analyzed. NVU is composed of neurons, glial and vascular cells ensuring the correct homeostasis of the blood-brain barrier (BBB) and indirectly the function of the central nervous system. The CCPLs phosphatidylcholine (lecithin), cytidine 5′-diphosphocholine (CDP-choline), choline alphoscerate or α-glyceryl-phosphorylcholine (α-GPC) contribute to the modulation of the physiology of the NVU cells. A loss of CCPLs contributes to the development of neurodegenerative diseases such as Alzheimer’s disease, multiple sclerosis, Parkinson’s disease. Our study has characterized the cellular components of the NVU and has reviewed the effect of lecithin, of CDP-choline and α-GPC documented in preclinical studies and in limited clinical trials on these compounds. The interesting results obtained with some CCPLs, in particular with α-GPC, probably would justify reconsideration of the most promising molecules in larger attentively controlled studies. This can also contribute to better define the role of the NVU in the pathophysiology of brain disorders characterized by vascular impairment.
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Affiliation(s)
- Proshanta Roy
- School of Biosciences and Veterinary Medicine, University of Camerino, Camerino, Italy
| | - Daniele Tomassoni
- School of Biosciences and Veterinary Medicine, University of Camerino, Camerino, Italy
| | - Giulio Nittari
- School of Medicinal and Health Products Sciences, University of Camerino, Camerino, Italy
| | - Enea Traini
- School of Medicinal and Health Products Sciences, University of Camerino, Camerino, Italy
| | - Francesco Amenta
- School of Medicinal and Health Products Sciences, University of Camerino, Camerino, Italy
- *Correspondence: Francesco Amenta,
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Puma DDL, Ripoli C, Puliatti G, Pastore F, Lazzarino G, Tavazzi B, Arancio O, Piacentini R, Grassi C. Extracellular tau oligomers affect extracellular glutamate handling by astrocytes through downregulation of GLT-1 expression and impairment of NKA1A2 function. Neuropathol Appl Neurobiol 2022; 48:e12811. [PMID: 35274343 PMCID: PMC9262805 DOI: 10.1111/nan.12811] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Revised: 02/14/2022] [Accepted: 02/26/2022] [Indexed: 11/29/2022]
Abstract
AIMS Several studies reported that astrocytes support neuronal communication by the release of gliotransmitters, including ATP and glutamate. Astrocytes also play a fundamental role in buffering extracellular glutamate in the synaptic cleft, thus limiting the risk of excitotoxicity in neurons. We previously demonstrated that extracellular tau oligomers (ex-oTau), by specifically targeting astrocytes, affect glutamate-dependent synaptic transmission via a reduction in gliotransmitter release. The aim of this work was to determine if ex-oTau also impair the ability of astrocytes to uptake extracellular glutamate, thus further contributing to ex-oTau-dependent neuronal dysfunction. METHODS Primary cultures of astrocytes and organotypic brain slices were exposed to ex-oTau (200 nM) for 1 hour. Extracellular glutamate buffering by astrocytes was studied by: Na+ imaging; electrophysiological recordings; high-performance liquid chromatography; Western blot and immunofluorescence. Experimental paradigms avoiding ex-oTau internalization (i.e., heparin pre-treatment and amyloid precursor protein knockout astrocytes) were used to dissect intracellular vs. extracellular effects of oTau. RESULTS Ex-oTau uploading in astrocytes significantly affected glutamate-transporter-1 expression and function, thus impinging on glutamate buffering activity. Ex-oTau also reduced Na-K-ATPase activity because of pump mislocalization on the plasma membrane, with no significant changes in expression. This effect was independent of oTau internalization and it caused Na+ overload and membrane depolarization in ex-oTau-targeted astrocytes. CONCLUSIONS Ex-oTau exerted a complex action on astrocytes, at both intracellular and extracellular levels. The net effect was dysregulated glutamate signalling in terms of both release and uptake that relied on reduced expression of glutamate-transporter-1, altered function and localization of NKA1A1, and NKA1A2. Consequently, Na+ gradients and all Na+ -dependent transports were affected.
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Affiliation(s)
- Domenica Donatella Li Puma
- Department of Neuroscience, Università Cattolica del Sacro Cuore, Rome, Italy.,Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy
| | - Cristian Ripoli
- Department of Neuroscience, Università Cattolica del Sacro Cuore, Rome, Italy.,Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy
| | - Giulia Puliatti
- Department of Neuroscience, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Francesco Pastore
- Department of Neuroscience, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Giacomo Lazzarino
- UniCamillus Saint Camillus International University of Health Sciences, Rome, Italy
| | - Barbara Tavazzi
- UniCamillus Saint Camillus International University of Health Sciences, Rome, Italy
| | - Ottavio Arancio
- Department of Pathology and Cell Biology, Taub Institute for Research on Alzheimer's Disease and the Aging Brain, and Department of Medicine, Columbia University, New York, NY, United States
| | - Roberto Piacentini
- Department of Neuroscience, Università Cattolica del Sacro Cuore, Rome, Italy.,Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy
| | - Claudio Grassi
- Department of Neuroscience, Università Cattolica del Sacro Cuore, Rome, Italy.,Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy
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Du H, Xu Y, Zhu L. Role of Semaphorins in Ischemic Stroke. Front Mol Neurosci 2022; 15:848506. [PMID: 35350431 PMCID: PMC8957939 DOI: 10.3389/fnmol.2022.848506] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Accepted: 02/17/2022] [Indexed: 12/12/2022] Open
Abstract
Ischemic stroke is one of the major causes of neurological morbidity and mortality in the world. Although the management of ischemic stroke has been improved significantly, it still imposes a huge burden on the health and property. The integrity of the neurovascular unit (NVU) is closely related with the prognosis of ischemic stroke. Growing evidence has shown that semaphorins, a family of axon guidance cues, play a pivotal role in multiple pathophysiological processes in NVU after ischemia, such as regulating the immune system, angiogenesis, and neuroprotection. Modulating the NVU function via semaphorin signaling has a potential to develop a novel therapeutic strategy for ischemic stroke. We, therefore, review recent progresses on the role of semphorin family members in neurons, glial cells and vasculature after ischemic stroke.
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Affiliation(s)
- Huaping Du
- Department of Neurology, Suzhou Ninth Hospital Affiliated to Soochow University, Suzhou, China
| | - Yuan Xu
- Department of Neurology, Suzhou Ninth Hospital Affiliated to Soochow University, Suzhou, China
| | - Li Zhu
- Department of Neurology, Suzhou Ninth Hospital Affiliated to Soochow University, Suzhou, China
- Suzhou Key Laboratory of Thrombosis and Vascular Biology, Jiangsu Key Laboratory of Preventive and Translational Medicine for Geriatric Diseases, Collaborative Innovation Center of Hematology of Jiangsu Province, National Clinical Research Center for Hematologic Diseases, Cyrus Tang Medical Institute, Soochow University, Suzhou, China
- *Correspondence: Li Zhu,
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Pabian-Jewuła S, Bragiel-Pieczonka A, Rylski M. Ying Yang 1 engagement in brain pathology. J Neurochem 2022; 161:236-253. [PMID: 35199341 DOI: 10.1111/jnc.15594] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Revised: 02/10/2022] [Accepted: 02/17/2022] [Indexed: 11/27/2022]
Abstract
Herein, we discuss data concerning the involvement of transcription factor Yin Yang 1 (YY1) in the development of brain diseases, highlighting mechanisms of its pathological actions. YY1 plays an important role in the developmental and adult pathology of the nervous system. YY1 is essential for neurulation as well as maintenance and differentiation of neuronal progenitor cells and oligodendrocytes regulating both neural and glial tissues of the brain. Lack of a YY1 gene causes many developmental abnormalities and anatomical malformations of the central nervous system (CNS). Once dysregulated, YY1 exerts multiple neuropathological actions being involved in the induction of many brain disorders like stroke, epilepsy, Alzheimer's and Parkinson's diseases, autism spectrum disorder, dystonia, and brain tumors. Better understanding of YY1's dysfunction in the nervous system may lead to the development of novel therapeutic strategies related to YY1's actions.
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Affiliation(s)
- Sylwia Pabian-Jewuła
- Department of Clinical Cytology, Centre of Postgraduate Medical Education, 99/103 Marymoncka Street, 01-813, Warsaw, Poland
| | - Aneta Bragiel-Pieczonka
- Department of Clinical Cytology, Centre of Postgraduate Medical Education, 99/103 Marymoncka Street, 01-813, Warsaw, Poland
| | - Marcin Rylski
- Department of Radiology, Institute of Psychiatry and Neurology, 9 Sobieski Street, Warsaw, Poland
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7
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The glutamatergic synapse: a complex machinery for information processing. Cogn Neurodyn 2021; 15:757-781. [PMID: 34603541 DOI: 10.1007/s11571-021-09679-w] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Revised: 03/04/2021] [Accepted: 04/16/2021] [Indexed: 10/21/2022] Open
Abstract
Being the most abundant synaptic type, the glutamatergic synapse is responsible for the larger part of the brain's information processing. Despite the conceptual simplicity of the basic mechanism of synaptic transmission, the glutamatergic synapse shows a large variation in the response to the presynaptic release of the neurotransmitter. This variability is observed not only among different synapses but also in the same single synapse. The synaptic response variability is due to several mechanisms of control of the information transferred among the neurons and suggests that the glutamatergic synapse is not a simple bridge for the transfer of information but plays an important role in its elaboration and management. The control of the synaptic information is operated at pre, post, and extrasynaptic sites in a sort of cooperation between the pre and postsynaptic neurons which also involves the activity of other neurons. The interaction between the different mechanisms of control is extremely complicated and its complete functionality is far from being fully understood. The present review, although not exhaustively, is intended to outline the most important of these mechanisms and their complexity, the understanding of which will be among the most intriguing challenges of future neuroscience.
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8
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Sommonte F, Arduino I, Racaniello GF, Lopalco A, Lopedota AA, Denora N. The Complexity of the Blood-Brain Barrier and the Concept of Age-Related Brain Targeting: Challenges and Potential of Novel Solid Lipid-Based Formulations. J Pharm Sci 2021; 111:577-592. [PMID: 34469749 DOI: 10.1016/j.xphs.2021.08.029] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Revised: 08/26/2021] [Accepted: 08/27/2021] [Indexed: 11/17/2022]
Abstract
Diseases that affect the Central Nervous System (CNS) are one of the most exciting challenges of recent years, as they are ubiquitous and affect all ages. Although these disorders show different etiologies, all treatments share the same difficulty represented by the Blood-Brain Barrier (BBB). This barrier acts as a protective system of the delicate cerebral microenvironment, isolating it and making extremely arduous delivering drugs to the brain. To overtake the obstacles provided by the BBB it is essential to explore the changes that affect it, to understand how to exploit these findings in the study and design of innovative brain targeted formulations. Interestingly, the concept of age-related targeting could prove to be a winning choice, as it allows to consider the type of treatment according to the different needs and peculiarities depending on the disease and the age of onset. In this review was considered the prospective contribution of lipid-based formulations, namely Solid Lipid Nanoparticles (SLNs) and Nanostructured Lipid Carriers (NLCs), which have been highlighted as able to overcome some limitations of other innovative approaches, thus representing a promising strategy for the non-invasive specific treatment of CNS-related diseases.
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Affiliation(s)
- Federica Sommonte
- Department of Pharmacy - Pharmaceutical Sciences, University of Bari "Aldo Moro", 4 Orabona St., 70125, Bari, Italy
| | - Ilaria Arduino
- Department of Pharmacy - Pharmaceutical Sciences, University of Bari "Aldo Moro", 4 Orabona St., 70125, Bari, Italy
| | | | - Antonio Lopalco
- Department of Pharmacy - Pharmaceutical Sciences, University of Bari "Aldo Moro", 4 Orabona St., 70125, Bari, Italy
| | - Angela Assunta Lopedota
- Department of Pharmacy - Pharmaceutical Sciences, University of Bari "Aldo Moro", 4 Orabona St., 70125, Bari, Italy
| | - Nunzio Denora
- Department of Pharmacy - Pharmaceutical Sciences, University of Bari "Aldo Moro", 4 Orabona St., 70125, Bari, Italy.
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9
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Price BR, Johnson LA, Norris CM. Reactive astrocytes: The nexus of pathological and clinical hallmarks of Alzheimer's disease. Ageing Res Rev 2021; 68:101335. [PMID: 33812051 PMCID: PMC8168445 DOI: 10.1016/j.arr.2021.101335] [Citation(s) in RCA: 62] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Revised: 01/21/2021] [Accepted: 03/20/2021] [Indexed: 02/06/2023]
Abstract
Astrocyte reactivity is a hallmark of neuroinflammation that arises with Alzheimer’s disease (AD) and nearly every other neurodegenerative condition. While astrocytes certainly contribute to classic inflammatory processes (e.g. cytokine release, waste clearance, and tissue repair), newly emerging technologies for measuring and targeting cell specific activities in the brain have uncovered essential roles for astrocytes in synapse function, brain metabolism, neurovascular coupling, and sleep/wake patterns. In this review, we use a holistic approach to incorporate, and expand upon, classic neuroinflammatory concepts to consider how astrocyte dysfunction/reactivity modulates multiple pathological and clinical hallmarks of AD. Our ever-evolving understanding of astrocyte signaling in neurodegeneration is not only revealing new drug targets and treatments for dementia but is suggesting we reimagine AD pathophysiological mechanisms.
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Affiliation(s)
- Brittani R Price
- Department of Neuroscience, Tufts University School of Medicine, 136 Harrison Ave., Boston, MA, 02111, USA
| | - Lance A Johnson
- Sanders-Brown Center on Aging, University of Kentucky, 800 S. Limestone St., Lexington, KY, 40356, USA; Department of Physiology, University of Kentucky, College of Medicine, UK Medical Center MN 150, Lexington, KY, 40536, USA
| | - Christopher M Norris
- Sanders-Brown Center on Aging, University of Kentucky, 800 S. Limestone St., Lexington, KY, 40356, USA; Department of Pharmacology and Nutritional Sciences, University of Kentucky, College of Medicine, UK Medical Center MN 150, Lexington, KY, 40536, USA.
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10
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Fan XC, Ma CN, Song JC, Liao ZH, Huang N, Liu X, Ma L. Rac1 Signaling in Amygdala Astrocytes Regulates Fear Memory Acquisition and Retrieval. Neurosci Bull 2021; 37:947-958. [PMID: 33909243 DOI: 10.1007/s12264-021-00677-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Accepted: 10/09/2020] [Indexed: 11/25/2022] Open
Abstract
The importance of astrocytes in behavior control is increasingly appreciated, but little is known about the effects of their dynamic activity in regulating learning and memory. In the present study, we constructed AAVs of photoactivatable and photoinactivatable Ras-related C3 botulinum toxin substrate 1 (Rac1) under the mGFAP promoter, which enabled the manipulation of Rac1 activity in astrocytes by optical stimulation in free-moving mice. We found that both up-regulation and down-regulation of astrocytic Rac1 activity in the basolateral amygdala (BLA) attenuated memory acquisition in a fear conditioning mouse model. Meanwhile, neuronal activation in the BLA induced by memory acquisition was inhibited under both the up- and down-regulation of astrocytic Rac1 activity during training. In terms of the impact on fear memory retrieval, we found both up- and down-regulation of BLA astrocytic Rac1 activity impaired memory retrieval of fear conditioning and memory retrieval-induced neuronal activation. Notably, the effect of astrocytic Rac1 on memory retrieval was reversible. Our results demonstrate that the normal activity of astrocytic Rac1 is necessary for the activation of neurons and memory formation. Both activation and inactivation of astrocytic Rac1 activity in the BLA reduced the excitability of neurons, and thereby impaired fear memory acquisition and retrieval.
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Affiliation(s)
- Xiao-Cen Fan
- Department of Neurosurgery, Huashan Hospital, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, School of Basic Medical Sciences, Institutes of Brain Science, Fudan University, Shanghai, 200032, China
| | - Chao-Nan Ma
- Department of Neurosurgery, Huashan Hospital, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, School of Basic Medical Sciences, Institutes of Brain Science, Fudan University, Shanghai, 200032, China
| | - Jia-Chen Song
- Department of Neurosurgery, Huashan Hospital, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, School of Basic Medical Sciences, Institutes of Brain Science, Fudan University, Shanghai, 200032, China
| | - Zhao-Hui Liao
- Department of Neurosurgery, Huashan Hospital, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, School of Basic Medical Sciences, Institutes of Brain Science, Fudan University, Shanghai, 200032, China
| | - Nan Huang
- Department of Neurosurgery, Huashan Hospital, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, School of Basic Medical Sciences, Institutes of Brain Science, Fudan University, Shanghai, 200032, China
| | - Xing Liu
- Department of Neurosurgery, Huashan Hospital, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, School of Basic Medical Sciences, Institutes of Brain Science, Fudan University, Shanghai, 200032, China.
| | - Lan Ma
- Department of Neurosurgery, Huashan Hospital, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, School of Basic Medical Sciences, Institutes of Brain Science, Fudan University, Shanghai, 200032, China.
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11
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Yamagata K. Astrocyte-induced synapse formation and ischemic stroke. J Neurosci Res 2021; 99:1401-1413. [PMID: 33604930 DOI: 10.1002/jnr.24807] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Accepted: 01/26/2021] [Indexed: 12/16/2022]
Abstract
Astrocytes are closely associated with the regulation of synapse formation and function. In addition, astrocytes have been shown to block certain brain impairments, including synaptic damage from stroke and other diseases of the central nervous system (CNS). Although astrocytes do not completely prevent synaptic damage, they appear to be protective and to restore synaptic function following damage. The purpose of this study is to discuss the role of astrocytes in synaptogenesis and synaptic damage in ischemic stroke. I detail the mechanism of action of the multiple factors secreted by astrocytes that are involved in synapse formation. In particular, I describe the characteristics and role in synapse formation of each secreted molecule related to synaptic structure and function. Furthermore, I discuss the effect of astrocytes on synaptogenesis and repair in ischemic stroke and in other CNS diseases. Astrocytes release molecules such as thrombospondin, hevin, secreted protein acidic rich in cysteine, etc., due to activation by ischemia to induce synaptic structure and function, an effect associated with protection of the brain from synaptic damage in ischemic stroke. In conclusion, I show that astrocytes may regulate synaptic transmission while having the potential to block and repair synaptic dysfunction in stroke-associated brain damage.
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Affiliation(s)
- Kazuo Yamagata
- Department of Food Bioscience & Biotechnology, College of Bioresource Science, Nihon University (UNBS), Fujisawa, Japan
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12
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Liu LR, Liu JC, Bao JS, Bai QQ, Wang GQ. Interaction of Microglia and Astrocytes in the Neurovascular Unit. Front Immunol 2020; 11:1024. [PMID: 32733433 PMCID: PMC7362712 DOI: 10.3389/fimmu.2020.01024] [Citation(s) in RCA: 246] [Impact Index Per Article: 61.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Accepted: 04/28/2020] [Indexed: 12/27/2022] Open
Abstract
The interaction between microglia and astrocytes significantly influences neuroinflammation. Microglia/astrocytes, part of the neurovascular unit (NVU), are activated by various brain insults. The local extracellular and intracellular signals determine their characteristics and switch of phenotypes. Microglia and astrocytes are activated into two polarization states: the pro-inflammatory phenotype (M1 and A1) and the anti-inflammatory phenotype (M2 and A2). During neuroinflammation, induced by stroke or lipopolysaccharides, microglia are more sensitive to pathogens, or damage; they are thus initially activated into the M1 phenotype and produce common inflammatory signals such as IL-1 and TNF-α to trigger reactive astrocytes into the A1 phenotype. These inflammatory signals can be amplified not only by the self-feedback loop of microglial activation but also by the unique anatomy structure of astrocytes. As the pathology further progresses, resulting in local environmental changes, M1-like microglia switch to the M2 phenotype, and M2 crosstalk with A2. While astrocytes communicate simultaneously with neurons and blood vessels to maintain the function of neurons and the blood-brain barrier (BBB), their subtle changes may be identified and responded by astrocytes, and possibly transferred to microglia. Although both microglia and astrocytes have different functional characteristics, they can achieve immune "optimization" through their mutual communication and cooperation in the NVU and build a cascaded immune network of amplification.
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Affiliation(s)
- Li-Rong Liu
- Shanxi Medical University, Taiyuan, China.,People's Hospital of Yaodu District, Linfen, China
| | - Jia-Chen Liu
- Xiangya Medical College, Central South University, Changsha, China
| | | | | | - Gai-Qing Wang
- Shanxi Medical University, Taiyuan, China.,SanYa Central Hospital, The Third People's Hospital of HaiNan Province, SanYa, China
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13
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Murru S, Hess S, Barth E, Almajan ER, Schatton D, Hermans S, Brodesser S, Langer T, Kloppenburg P, Rugarli EI. Astrocyte-specific deletion of the mitochondrial m-AAA protease reveals glial contribution to neurodegeneration. Glia 2019; 67:1526-1541. [PMID: 30989755 PMCID: PMC6618114 DOI: 10.1002/glia.23626] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Revised: 04/02/2019] [Accepted: 04/04/2019] [Indexed: 12/15/2022]
Abstract
Mitochondrial dysfunction causes neurodegeneration but whether impairment of mitochondrial homeostasis in astrocytes contributes to this pathological process remains largely unknown. The m‐AAA protease exerts quality control and regulatory functions crucial for mitochondrial homeostasis. AFG3L2, which encodes one of the subunits of the m‐AAA protease, is mutated in spinocerebellar ataxia SCA28 and in infantile syndromes characterized by spastic‐ataxia, epilepsy and premature death. Here, we investigate the role of Afg3l2 and its redundant homologue Afg3l1 in the Bergmann glia (BG), radial astrocytes of the cerebellum that have functional connections with Purkinje cells (PC) and regulate glutamate homeostasis. We show that astrocyte‐specific deletion of Afg3l2 in the mouse leads to late‐onset motor impairment and to degeneration of BG, which display aberrant morphology, altered expression of the glutamate transporter EAAT2, and a reactive inflammatory signature. The neurological and glial phenotypes are drastically exacerbated when astrocytes lack both Afg31l and Afg3l2, and therefore, are totally depleted of the m‐AAA protease. Moreover, mitochondrial stress responses and necroptotic markers are induced in the cerebellum. In both mouse models, targeted BG show a fragmented mitochondrial network and loss of mitochondrial cristae, but no signs of respiratory dysfunction. Importantly, astrocyte‐specific deficiency of Afg3l1 and Afg3l2 triggers secondary morphological degeneration and electrophysiological changes in PCs, thus demonstrating a non‐cell‐autonomous role of glia in neurodegeneration. We propose that astrocyte dysfunction amplifies both neuroinflammation and glutamate excitotoxicity in patients carrying mutations in AFG3L2, leading to a vicious circle that contributes to neuronal death.
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Affiliation(s)
- Sara Murru
- Department of Biology, Institute for Genetics, University of Cologne, Cologne, Germany.,Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
| | - Simon Hess
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany.,Department of Biology, Institute for Zoology, Biocenter, University of Cologne, Cologne, Germany
| | - Esther Barth
- Department of Biology, Institute for Genetics, University of Cologne, Cologne, Germany.,Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
| | - Eva R Almajan
- Department of Biology, Institute for Genetics, University of Cologne, Cologne, Germany.,Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
| | - Désirée Schatton
- Department of Biology, Institute for Genetics, University of Cologne, Cologne, Germany.,Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
| | - Steffen Hermans
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
| | - Susanne Brodesser
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
| | - Thomas Langer
- Department of Mitochondrial Proteostasis, Max-Planck-Institute for Biology of Ageing, Cologne, Germany
| | - Peter Kloppenburg
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany.,Department of Biology, Institute for Zoology, Biocenter, University of Cologne, Cologne, Germany
| | - Elena I Rugarli
- Department of Biology, Institute for Genetics, University of Cologne, Cologne, Germany.,Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
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14
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Hagos FT, Adams SM, Poloyac SM, Kochanek PM, Horvat CM, Clark RSB, Empey PE. Membrane transporters in traumatic brain injury: Pathological, pharmacotherapeutic, and developmental implications. Exp Neurol 2019; 317:10-21. [PMID: 30797827 DOI: 10.1016/j.expneurol.2019.02.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2018] [Revised: 02/12/2019] [Accepted: 02/20/2019] [Indexed: 12/12/2022]
Abstract
Membrane transporters regulate the trafficking of endogenous and exogenous molecules across biological barriers and within the neurovascular unit. In traumatic brain injury (TBI), they moderate the dynamic movement of therapeutic drugs and injury mediators among neurons, endothelial cells and glial cells, thereby becoming important determinants of pathogenesis and effective pharmacotherapy after TBI. There are three ways transporters may impact outcomes in TBI. First, transporters likely play a key role in the clearance of injury mediators. Second, genetic association studies suggest transporters may be important in the transition of TBI from acute brain injury to a chronic neurological disease. Third, transporters dynamically control the brain penetration and efflux of many drugs and their distribution within and elimination from the brain, contributing to pharmacoresistance and possibly in some cases pharmacosensitivity. Understanding the nature of drugs or candidate drugs in development with respect to whether they are a transporter substrate or inhibitor is relevant to understand whether they distribute to their target in sufficient concentrations. Emerging data provide evidence of altered expression and function of transporters in humans after TBI. Genetic variability in expression and/or function of key transporters adds an additional dynamic, as shown in recent clinical studies. In this review, evidence supporting the role of individual membrane transporters in TBI are discussed as well as novel strategies for their modulation as possible therapeutic targets. Since data specifically targeting pediatric TBI are sparse, this review relies mainly on experimental studies using adult animals and clinical studies in adult patients.
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Affiliation(s)
- Fanuel T Hagos
- Center for Clinical Pharmaceutical Sciences, School of Pharmacy, University of Pittsburgh, PA, United States of America
| | - Solomon M Adams
- Center for Clinical Pharmaceutical Sciences, School of Pharmacy, University of Pittsburgh, PA, United States of America
| | - Samuel M Poloyac
- Center for Clinical Pharmaceutical Sciences, School of Pharmacy, University of Pittsburgh, PA, United States of America; Safar Center for Resuscitation Research, University of Pittsburgh, Pittsburgh, PA, United States of America
| | - Patrick M Kochanek
- Safar Center for Resuscitation Research, University of Pittsburgh, Pittsburgh, PA, United States of America; Department of Critical Care Medicine, University of Pittsburgh, Pittsburgh, PA, United States of America; UPMC Children's Hospital of Pittsburgh, Pittsburgh, PA, United States of America
| | - Christopher M Horvat
- Safar Center for Resuscitation Research, University of Pittsburgh, Pittsburgh, PA, United States of America; Department of Critical Care Medicine, University of Pittsburgh, Pittsburgh, PA, United States of America; UPMC Children's Hospital of Pittsburgh, Pittsburgh, PA, United States of America
| | - Robert S B Clark
- Safar Center for Resuscitation Research, University of Pittsburgh, Pittsburgh, PA, United States of America; Department of Critical Care Medicine, University of Pittsburgh, Pittsburgh, PA, United States of America; UPMC Children's Hospital of Pittsburgh, Pittsburgh, PA, United States of America.
| | - Philip E Empey
- Center for Clinical Pharmaceutical Sciences, School of Pharmacy, University of Pittsburgh, PA, United States of America; Safar Center for Resuscitation Research, University of Pittsburgh, Pittsburgh, PA, United States of America.
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15
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Tsai SF, Wu HT, Chen PC, Chen YW, Yu M, Wang TF, Wu SY, Tzeng SF, Kuo YM. High-fat diet suppresses the astrocytic process arborization and downregulates the glial glutamate transporters in the hippocampus of mice. Brain Res 2018; 1700:66-77. [DOI: 10.1016/j.brainres.2018.07.017] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2018] [Revised: 07/11/2018] [Accepted: 07/12/2018] [Indexed: 01/02/2023]
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16
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Neves J, Vizuete A, Nicola F, Da Ré C, Rodrigues A, Schmitz F, Mestriner R, Aristimunha D, Wyse A, Netto C. Glial glutamate transporters expression, glutamate uptake, and oxidative stress in an experimental rat model of intracerebral hemorrhage. Neurochem Int 2018. [DOI: 10.1016/j.neuint.2018.03.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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17
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Monti L, Morbidelli L, Rossi A. Impaired Cerebral Perfusion in Multiple Sclerosis: Relevance of Endothelial Factors. Biomark Insights 2018; 13:1177271918774800. [PMID: 29795976 PMCID: PMC5960845 DOI: 10.1177/1177271918774800] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2018] [Accepted: 04/07/2018] [Indexed: 12/21/2022] Open
Abstract
Magnetic resonance imaging techniques measuring in vivo brain perfusion and integrity of the blood-brain barrier have developed rapidly in the past decade, resulting in a wide range of available methods. This review first discusses their principles, possible pitfalls, and potential for quantification and outlines clinical application in neurological disorders. Then, we focus on the endothelial cells of the blood-brain barrier, pointing out their contribution in regulating vascular tone by production of vasoactive substances. Finally, the role of these substances in brain hypoperfusion in multiple sclerosis is discussed.
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Affiliation(s)
- Lucia Monti
- Unit of Neuroimaging and Neurointervention, Department of Neurological and Neurosensory Sciences, "Santa Maria alle Scotte" General Hospital, University Hospital of Siena, Siena, Italy
| | | | - Alessandro Rossi
- Unit of Neurology and Clinical Neurophysiology, Department of Neurological and Neurosensory Sciences, University Hospital of Siena, Siena, Italy
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18
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Cappelletti P, Tallarita E, Rabattoni V, Campomenosi P, Sacchi S, Pollegioni L. Proline oxidase controls proline, glutamate, and glutamine cellular concentrations in a U87 glioblastoma cell line. PLoS One 2018; 13:e0196283. [PMID: 29694413 PMCID: PMC5918996 DOI: 10.1371/journal.pone.0196283] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2017] [Accepted: 04/10/2018] [Indexed: 12/11/2022] Open
Abstract
L-Proline is a multifunctional amino acid that plays an essential role in primary metabolism and physiological functions. Proline is oxidized to glutamate in the mitochondria and the FAD-containing enzyme proline oxidase (PO) catalyzes the first step in L-proline degradation pathway. Alterations in proline metabolism have been described in various human diseases, such as hyperprolinemia type I, velo-cardio-facial syndrome/Di George syndrome, schizophrenia and cancer. In particular, the mutation giving rise to the substitution Leu441Pro was identified in patients suffering of schizophrenia and hyperprolinemia type I. Here, we report on the expression of wild-type and L441P variants of human PO in a U87 glioblastoma human cell line in an attempt to assess their effect on glutamate metabolism. The subcellular localization of the flavoenzyme is not altered in the L441P variant, for which specific activity is halved compared to the wild-type PO. While this decrease in activity is significantly less than that previously proposed, an effect of the substitution on the enzyme stability is also apparent in our studies. At 24 hours of growth from transient transfection, the intracellular level of proline, glutamate, and glutamine is decreased in cells expressing the PO variants as compared to control U87 cells, reaching a similar figure at 72 h. On the other hand, the extracellular levels of the three selected amino acids show a similar time course for all clones. Furthermore, PO overexpression does not modify to a significant extent the expression of GLAST and GLT-1 glutamate transporters. Altogether, these results demonstrate that the proline pathway links cellular proline levels with those of glutamate and glutamine. On this side, PO might play a regulatory role in glutamatergic neurotransmission by affecting the cellular concentration of glutamate.
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Affiliation(s)
- Pamela Cappelletti
- Department of Biotechnology and Life Sciences, University of Insubria, Varese, Italy
- The Protein Factory Research Center, Politecnico of Milano and University of Insubria, Milano, Italy
- * E-mail:
| | - Elena Tallarita
- Department of Biotechnology and Life Sciences, University of Insubria, Varese, Italy
| | - Valentina Rabattoni
- Department of Biotechnology and Life Sciences, University of Insubria, Varese, Italy
| | - Paola Campomenosi
- Department of Biotechnology and Life Sciences, University of Insubria, Varese, Italy
- The Protein Factory Research Center, Politecnico of Milano and University of Insubria, Milano, Italy
| | - Silvia Sacchi
- Department of Biotechnology and Life Sciences, University of Insubria, Varese, Italy
- The Protein Factory Research Center, Politecnico of Milano and University of Insubria, Milano, Italy
| | - Loredano Pollegioni
- Department of Biotechnology and Life Sciences, University of Insubria, Varese, Italy
- The Protein Factory Research Center, Politecnico of Milano and University of Insubria, Milano, Italy
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19
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Wipfler P, Dunn N, Beiki O, Trinka E, Fogdell-Hahn A. The Viral Hypothesis of Mesial Temporal Lobe Epilepsy – Is Human Herpes Virus-6 the Missing Link? A systematic review and meta-analysis. Seizure 2018; 54:33-40. [DOI: 10.1016/j.seizure.2017.11.015] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Revised: 11/21/2017] [Accepted: 11/24/2017] [Indexed: 12/26/2022] Open
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20
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Huang S, Tong H, Lei M, Zhou M, Guo W, Li G, Tang X, Li Z, Mo M, Zhang X, Chen X, Cen L, Wei L, Xiao Y, Li K, Huang Q, Yang X, Liu W, Zhang L, Qu S, Li S, Xu P. Astrocytic glutamatergic transporters are involved in Aβ-induced synaptic dysfunction. Brain Res 2017; 1678:129-137. [PMID: 29066369 DOI: 10.1016/j.brainres.2017.10.011] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2017] [Revised: 10/10/2017] [Accepted: 10/11/2017] [Indexed: 01/15/2023]
Abstract
In Alzheimer's disease (AD), dementia severity correlates most strongly with decreased synapse density in the hippocampus and cerebral cortex. Although studies in rodents have established that hippocampal long-term potentiation (LTP) is inhibited by soluble oligomers of beta-amyloid (Aβ), the synaptic mechanisms remain unclear. Here, field excitatory postsynaptic potentials (fEPSP) recordings were made in the CA1 region of mouse hippocampal slices. The medium of APP-expressing CHO cells, which contain soluble forms of Aβ including small oligomers, inhibited LTP and facilitated long-term depression (LTD), thus making the LTP/LTD curve shift toward the right. This phenomenon could be mimicked by the non-selective glutamate transporter inhibitor, DL-TBOA. More specifically, the Aβ impaired LTP and facilitated LTD were occluded by the selective astrocytic glutamate transporter inhibitors, TFB-TBOA. In cultured astrocytes, the Aβ oligomers also decrease astrocytic glutamate transporters (EAAT1, EAAT2) expression. We conclude that soluble Aβ oligomers decrease the activation of astrocytic glutamate transporters, thereby impairing synaptic plasticity.
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Affiliation(s)
- Shuxuan Huang
- Department of Neurology, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong 510120, China
| | - Huichun Tong
- Clinical Medicine Research Centre, Shunde Hospital, Southern Medical University, Foshan, Guangdong 528300, China; Department of Neurology, Shunde Hospital, Southern Medical University, Foshan, Guangdong 528300, China
| | - Ming Lei
- Department of Neurology, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong 510120, China; Department of Neurology, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong 510080, China
| | - Miaomiao Zhou
- Department of Neurology, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong 510120, China
| | - Wenyuan Guo
- Department of Neurology, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong 510120, China
| | - Guihua Li
- Department of Neurology, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong 510120, China
| | - Xiaolu Tang
- Department of Neurology, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong 510120, China
| | - Zhe Li
- Department of Neurology, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong 510120, China
| | - Mingshu Mo
- Department of Neurology, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong 510120, China
| | - Xiuping Zhang
- Teaching Center of Experimental Medicine, School of Basic Medical Sciences, Southern Medical University, Guangzhou, Guangdong 510515, China
| | - Xiang Chen
- Department of Neurology, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong 510120, China
| | - Luan Cen
- Department of Neurology, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong 510120, China
| | - Lei Wei
- Department of Neurology, The Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong 510082, China
| | - Yousheng Xiao
- Department of Neurology, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong 510120, China
| | - Kaiping Li
- State Key Laboratory of Respiratory Disease, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong 510120, China
| | - Qinghui Huang
- Department of Neurology, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong 510120, China; State Key Laboratory of Respiratory Disease, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong 510120, China
| | - Xinling Yang
- Department of Neurology, The Third Affiliated Hospital of Xinjiang Medical University, Urumqi, Xinjiang 830011, China
| | - Weiguo Liu
- Department of Geroatric&Neurology, Affiliated Brain Hospital of Nanjing Medical University, Nanjing, Jiangsu 210029, China
| | - Li Zhang
- Department of Geroatric&Neurology, Affiliated Brain Hospital of Nanjing Medical University, Nanjing, Jiangsu 210029, China
| | - Shaogang Qu
- Clinical Medicine Research Centre, Shunde Hospital, Southern Medical University, Foshan, Guangdong 528300, China; Department of Neurology, Shunde Hospital, Southern Medical University, Foshan, Guangdong 528300, China.
| | - Shaomin Li
- Department of Neurology, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong 510120, China; Ann Romney Center for Neurologic Disease, Brigham and Women's Hospital of Harvard Medical School, Boston, MA 02115, USA.
| | - Pingyi Xu
- Department of Neurology, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong 510120, China.
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21
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Drugs to Alter Extracellular Concentration of Glutamate: Modulators of Glutamate Uptake Systems. ACTA ACUST UNITED AC 2017. [DOI: 10.1007/978-1-4939-7228-9_7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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22
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Suárez-Pozos E, Martínez-Lozada Z, Méndez-Flores OG, Guillem AM, Hernández-Kelly LC, Castelán F, Olivares-Bañuelos TN, Chi-Castañeda D, Najimi M, Ortega A. Characterization of the cystine/glutamate antiporter in cultured Bergmann glia cells. Neurochem Int 2017; 108:52-59. [DOI: 10.1016/j.neuint.2017.02.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Revised: 01/27/2017] [Accepted: 02/20/2017] [Indexed: 01/18/2023]
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23
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Rodríguez A, Ortega A. Glutamine/Glutamate Transporters in Glial Cells: Much More Than Participants of a Metabolic Shuttle. ADVANCES IN NEUROBIOLOGY 2017; 16:169-183. [PMID: 28828610 DOI: 10.1007/978-3-319-55769-4_8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Glial glutamine and glutamate transporters play an important role in glial/neuronal interactions. An excellent model to establish the role of these membrane proteins is the cerebellum. The most abundant glutamatergic synapse in the central nervous system is present in the molecular layer of the cerebellar cortex, and it is entirely wrapped by Bergmann glial cells. The recycling of glutamate involves glutamate and glutamine transporters enriched in these radial glial processes. The functional properties of amino acid glial transporters allow, in an activity-dependent manner, the conformation of protein complexes important for the adequate support of glutamatergic neurotransmission. A detailed description of the most important features of glial glutamate and glutamine transporters follows, and a working model of the molecular mechanisms by which these glutamate and glutamine binding proteins interact, and by these means might modulate cerebellar glutamatergic transactions, is presented.
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Affiliation(s)
- Angelina Rodríguez
- Facultad de Ciencias Naturales, Universidad Autónoma de Querétaro, Centro Universitario, Querétaro, México
| | - Arturo Ortega
- Departamento de Toxicología, Cinvestav-IPN, Apartado Postal 14-740, México, DF, 07360, México.
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24
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25
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Chrobak AA, Soltys Z. Bergmann Glia, Long-Term Depression, and Autism Spectrum Disorder. Mol Neurobiol 2016; 54:1156-1166. [PMID: 26809583 PMCID: PMC5310553 DOI: 10.1007/s12035-016-9719-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Accepted: 01/12/2016] [Indexed: 12/22/2022]
Abstract
Bergmann glia (BG), a specific type of radial astrocytes in the cerebellum, play a variety of vital functions in the development of this structure. However, the possible role of BG in the development of abnormalities observed in individuals with autism spectrum disorder (ASD) seems to be underestimated. One of the most consistent findings observed in ASD patients is loss of Purkinje cells (PCs). Such a defect may be caused by dysregulation of glutamate homeostasis, which is maintained mainly by BG. Moreover, these glial cells are involved in long-term depression (LTD), a form of plasticity which can additionally subserve neuroprotective functions. The aim of presented review is to summarize the current knowledge about interactions which occur between PC and BG, with special emphasis on those which are relevant to the survival and proper functioning of cerebellar neurons.
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Affiliation(s)
- Adrian Andrzej Chrobak
- Department of Neuroanatomy, Institute of Zoology, Jagiellonian University, Gronostajowa St. 9, Cracow, 30-387, Poland. .,Faculty of Medicine, Jagiellonian University Medical College, Kopernika St. 21A, Cracow, 31-501, Poland.
| | - Zbigniew Soltys
- Department of Neuroanatomy, Institute of Zoology, Jagiellonian University, Gronostajowa St. 9, Cracow, 30-387, Poland
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26
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Pandey R, Ghorpade A. Cytosolic phospholipase A2 regulates alcohol-mediated astrocyte inflammatory responses in HIV-associated neurocognitive disorders. Cell Death Discov 2015; 1:15045. [PMID: 27551474 PMCID: PMC4979440 DOI: 10.1038/cddiscovery.2015.45] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Accepted: 09/12/2015] [Indexed: 01/09/2023] Open
Abstract
Alcohol (EtOH) abuse and HIV-1 infection remain leading public health problems not only in the United States but also across the world. Alcohol abusers have a significantly greater risk of HIV-1 infection than non-drinkers globally. In the United States, prevalence of EtOH abuse is over two-fold higher in HIV-1-positive individuals than that of the general population. Although alcohol abusers show neurodegeneration, exacerbated neuroinflammation and oxidative damage, the mechanism(s) by which EtOH regulates astrocyte inflammatory responses in HIV-associated neurocognitive disorders is unknown. Thus, we explored signaling pathway(s) involved in EtOH-mediated activation of human astrocytes with HIV-1 and subsequent alterations in their inflammatory functions. Alcohol exposure altered the morphology of astrocytes, proinflammatory responses and induced cytotoxicity in a dose-dependent manner. Time-dependent changes were also evaluated. EtOH and HIV-1 cotreatment decreased cell viability and proliferation, while increasing apoptosis and mitochondrial depolarization. EtOH and HIV-1 together increased the levels of proinflammatory molecules, interleukin-1β, tumor necrosis factor-α, CXCL8, tissue inhibitor of metalloproteinases-1 and more importantly, arachidonic acid, a known downstream target of cytosolic phospholipase A2 (cPLA2). Consistent with this observation, phospho-cPLA2 levels were augmented in HIV-1 and EtOH cotreatment as compared with HIV-1 or EtOH alone. Cyclooxygenase 2 was upregulated as measured by real-time PCR and western blot, whereas cotreatment of HIV-1 and EtOH decreased cytochrome P450-2E1 levels as compared with EtOH alone. Furthermore, we confirmed that blocking cPLA2 with arachidonyl tri floro methyl ketone, a cPLA2-specific inhibitor, effectively prevented cPLA2 phosphorylation and downstream outcomes. Thus, the present findings suggest that cPLA2 has a critical role in alcohol and HIV-induced astrocyte inflammation. In the future, cPLA2 inhibitors may present novel therapeutic tools to treat alcohol abuse and HIV-associated neurocognitive disorder comorbidity.
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Affiliation(s)
- R Pandey
- Department of Cell Biology and Immunology, University of North Texas Health Science Center , Fort Worth, TX, USA
| | - A Ghorpade
- Department of Cell Biology and Immunology, University of North Texas Health Science Center , Fort Worth, TX, USA
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27
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Fontana ACK. Current approaches to enhance glutamate transporter function and expression. J Neurochem 2015; 134:982-1007. [DOI: 10.1111/jnc.13200] [Citation(s) in RCA: 105] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2015] [Revised: 05/19/2015] [Accepted: 05/20/2015] [Indexed: 12/12/2022]
Affiliation(s)
- Andréia C. K. Fontana
- Department of Pharmacology and Physiology; Drexel University College of Medicine; Philadelphia Pennsylvania USA
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28
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Glutamatergic Transmission: A Matter of Three. Neural Plast 2015; 2015:787396. [PMID: 26345375 PMCID: PMC4539489 DOI: 10.1155/2015/787396] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Accepted: 03/18/2015] [Indexed: 12/11/2022] Open
Abstract
Glutamatergic transmission in the vertebrate brain requires the involvement of glia cells, in a continuous molecular dialogue. Glial glutamate receptors and transporters are key molecules that sense synaptic activity and by these means modify their physiology in the short and long term. Posttranslational modifications that regulate protein-protein interactions and modulate transmitter removal are triggered in glial cells by neuronal released glutamate. Moreover, glutamate signaling cascades in these cells are linked to transcriptional and translational control and are critically involved in the control of the so-called glutamate/glutamine shuttle and by these means in glutamatergic neurotransmission. In this contribution, we summarize our current understanding of the biochemical consequences of glutamate synaptic activity in their surrounding partners and dissect the molecular mechanisms that allow neurons to take control of glia physiology to ensure proper glutamate-mediated neuronal communication.
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29
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Abstract
Astrocytes regulate multiple aspects of neuronal and synaptic function from development through to adulthood. Instead of addressing each function independently, this review provides a comprehensive overview of the different ways astrocytes modulate neuronal synaptic function throughout life, with a particular focus on recent findings in each area. It includes the emerging functions of astrocytes, such as a role in synapse formation, as well as more established roles, including the uptake and recycling of neurotransmitters. This broad approach covers the many ways astrocytes and neurons constantly interact to maintain the correct functioning of the brain. It is important to consider all of these diverse functions of astrocytes when investigating how astrocyte-neuron interactions regulate synaptic behavior to appreciate the complexity of these ongoing interactions.
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Affiliation(s)
- Nicola J Allen
- Salk Institute for Biological Studies, La Jolla, California 92037;
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30
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Tong H, Yu X, Lu X, Wang P. Downregulation of solute carriers of glutamate in gliosomes and synaptosomes may explain local brain metastasis in anaplastic glioblastoma. IUBMB Life 2015; 67:306-11. [PMID: 25914026 DOI: 10.1002/iub.1372] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Accepted: 02/28/2015] [Indexed: 12/31/2022]
Abstract
Advanced grades of glioblastoma are highly aggressive, especially in terms of multisite spread within the brain or even to distant sites at the spinal cord. In advanced grades of glioblastoma, glutamate and glutamine are reported to be increased in concentration in the extracellular fluid. It has been reported that glutamate acts as an extracellular signaling molecule for facilitating local spread of advanced grades of glioblastoma. In the present study, we aimed to examine whether glutamate uptake mechanisms is impaired in advanced glioblastoma. The possible downregulated mechanisms of glutamate uptake would facilitate persistence of glutamate in the extracellular environment, rather than intracellular uptake. We obtained biobanked human specimens of glioblastoma and tested expression of proteins belonging to the solute carrier families of proteins that are known to function as membrane-located excitatory amino acid like glutamate transporters. The present study provides preliminary evidence of the downregulation of membrane expression of excitatory amino acid transporters solute carrier family 1 member 3 (SLC1A3) and its palmitoylated form in gliosomes, as well as SLC1A2 in the glio-synaptosomes. Compounds like riluzole used in the treatment of amyotrophic lateral sclerosis and the antibiotic ceftriaxone have the potential to facilitate glutamate uptake. These medications may be examined as adjunct chemotherapy in the massively aggressive tumor glioblastoma multiforme.
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Affiliation(s)
- Huaiyu Tong
- Department of Neurosurgery, Chinese PLA General Hospital, Beijing, 100853, China
| | - Xinguang Yu
- Department of Neurosurgery, Chinese PLA General Hospital, Beijing, 100853, China
| | - Xuechun Lu
- Department of Hematology, Chinese PLA General Hospital, Beijing, 100853, China
| | - Peng Wang
- Department of Neurosurgery, Chinese PLA General Hospital, Beijing, 100853, China
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31
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The transmembrane transporter domain of glutamate transporters is a process tip localizer. Sci Rep 2015; 5:9032. [PMID: 25761899 PMCID: PMC4357008 DOI: 10.1038/srep09032] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2014] [Accepted: 02/10/2015] [Indexed: 01/09/2023] Open
Abstract
Glutamate transporters in the central nervous system remove glutamate released from neurons to terminate the signal. These transporters localize to astrocyte process tips approaching neuronal synapses. The mechanisms underlying the localization of glutamate transporters to these processes, however, are not known. In this study, we demonstrate that the trimeric transmembrane transporter domain fragment of glutamate transporters, lacking both N- and C-terminal cytoplasmic regions, localized to filopodia tips. This is a common property of trimeric transporters including a neutral amino acid transporter ASCT1. Astrocyte specific proteins are not required for the filopodia tip localization. An extracellular loop at the centre of the 4th transmembrane helices, unique for metazoans, is required for the localization. Moreover, a C186S mutation at the 4th transmembrane region of EAAT1, found in episodic ataxia patients, significantly decreased its process tip localization. The transmembrane transporter domain fragments of glutamate transporters also localized to astrocyte process tips in cultured hippocampal slice. These results indicate that the transmembrane transporter domain of glutamate transporters have an additional function as a sorting signal to process tips.
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Robinson CR, Dougherty PM. Spinal astrocyte gap junction and glutamate transporter expression contributes to a rat model of bortezomib-induced peripheral neuropathy. Neuroscience 2014; 285:1-10. [PMID: 25446343 DOI: 10.1016/j.neuroscience.2014.11.009] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2014] [Revised: 11/04/2014] [Accepted: 11/05/2014] [Indexed: 01/01/2023]
Abstract
There is increasing evidence implicating astrocytes in multiple forms of chronic pain, as well as in the specific context of chemotherapy-induced peripheral neuropathy (CIPN). However, it is still unclear what the exact role of astrocytes may be in the context of CIPN. Findings in oxaliplatin and paclitaxel models have displayed altered expression of astrocytic gap junctions and glutamate transporters as means by which astrocytes may contribute to observed behavioral changes. The current study investigated whether these changes were also generalizable to the bortezomib CIPN. Changes in mechanical sensitivity were verified in bortezomib-treated animals, and these changes were prevented by co-treatment with a glial activation inhibitor (minocycline), a gap junction decoupler (carbenoxolone), and by a glutamate transporter upregulator (ceftriaxone). Immunohistochemistry data at day 30 in bortezomib-treated animals showed increases in expression of glial fibrillary acidic protein (GFAP) and connexin 43 but a decrease in GLAST expression. These changes were prevented by co-treatment with minocycline. Follow-up Western blotting data showed a shift in connexin 43 from a non-phosphorylated state to a phosphorylated state, indicating increased trafficking of expressed connexin 43 to the cell membrane. These data suggest that increases in behavioral sensitivity to cutaneous stimuli may be tied to persistent synaptic glutamate resulting from increased calcium flow between spinal astrocytes.
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Affiliation(s)
- C R Robinson
- The Department of Anesthesiology and Pain Medicine Research, The University of Texas M.D. Anderson Cancer Center, 1400 Holcombe, Unit 409, Houston, TX 77030, Unites States
| | - P M Dougherty
- The Department of Anesthesiology and Pain Medicine Research, The University of Texas M.D. Anderson Cancer Center, 1400 Holcombe, Unit 409, Houston, TX 77030, Unites States.
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Gegelashvili G, Bjerrum OJ. High-affinity glutamate transporters in chronic pain: an emerging therapeutic target. J Neurochem 2014; 131:712-30. [DOI: 10.1111/jnc.12957] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Revised: 09/18/2014] [Accepted: 09/25/2014] [Indexed: 01/13/2023]
Affiliation(s)
- Georgi Gegelashvili
- Department of Drug Design and Pharmacology; Faculty of Health and Medical Sciences; University of Copenhagen; Copenhagen Denmark
- Institute of Chemical Biology; Ilia State University; Tbilisi Georgia
| | - Ole J. Bjerrum
- Department of Drug Design and Pharmacology; Faculty of Health and Medical Sciences; University of Copenhagen; Copenhagen Denmark
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34
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Vartak-Sharma N, Gelman BB, Joshi C, Borgamann K, Ghorpade A. Astrocyte elevated gene-1 is a novel modulator of HIV-1-associated neuroinflammation via regulation of nuclear factor-κB signaling and excitatory amino acid transporter-2 repression. J Biol Chem 2014; 289:19599-612. [PMID: 24855648 DOI: 10.1074/jbc.m114.567644] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Astrocyte elevated gene-1 (AEG-1), a novel human immunodeficiency virus (HIV)-1 and tumor necrosis factor (TNF)-α-inducible oncogene, has generated significant interest in the field of cancer research as a therapeutic target for many metastatic aggressive tumors. However, little is known about its role in astrocyte responses during HIV-1 central nervous system (CNS) infection and whether it contributes toward the development of HIV-associated neurocognitive disorders (HAND). Therefore, in this study, we investigated changes in AEG-1 CNS expression in HIV-1-infected brain tissues and elucidated a potential mechanism of AEG-1-mediated regulation of HAND. Immunoblotting and immunohistochemical analyses of HIV-1 seropositive and HIV-1 encephalitic human brain tissues revealed significantly elevated levels of AEG-1 protein. Immunohistochemical analyses of HIV-1 Tat transgenic mouse brain tissues also showed a marked increase in AEG-1 staining. Similar to in vivo observations, cultured astrocytes expressing HIV-1 Tat also revealed AEG-1 and cytokine up-regulation. Astrocytes treated with HAND-relevant stimuli, TNF-α, interleukin (IL)-1β, and HIV-1, also significantly induced AEG-1 expression and nuclear translocation via activation of the nuclear factor (NF)-κB pathway. Co-immunoprecipitation studies demonstrated IL-1β- or TNF-α-induced AEG-1 interaction with NF-κB p65 subunit. AEG-1 knockdown decreased NF-κB activation, nuclear translocation, and transcriptional output in TNF-α-treated astrocytes. Moreover, IL-1β treatment of AEG-1-overexpressing astrocytes significantly lowered expression of excitatory amino acid transporter 2, increased expression of excitatory amino acid transporter 2 repressor ying yang 1, and reduced glutamate clearance, a major transducer of excitotoxic neuronal damage. Findings from this study identify a novel transcriptional co-factor function of AEG-1 and further implicate AEG-1 in HAND-associated neuroinflammation.
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Affiliation(s)
- Neha Vartak-Sharma
- From the Department of Cell Biology and Immunology, University of North Texas Health Science Center, Fort Worth, Texas 76107 and
| | - Benjamin B Gelman
- the Departments of Pathology and Neuroscience & Cell Biology, University of Texas Medical Branch, Galveston, Texas 77555
| | - Chaitanya Joshi
- From the Department of Cell Biology and Immunology, University of North Texas Health Science Center, Fort Worth, Texas 76107 and
| | - Kathleen Borgamann
- From the Department of Cell Biology and Immunology, University of North Texas Health Science Center, Fort Worth, Texas 76107 and
| | - Anuja Ghorpade
- From the Department of Cell Biology and Immunology, University of North Texas Health Science Center, Fort Worth, Texas 76107 and
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35
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Muoio V, Persson PB, Sendeski MM. The neurovascular unit - concept review. Acta Physiol (Oxf) 2014; 210:790-8. [PMID: 24629161 DOI: 10.1111/apha.12250] [Citation(s) in RCA: 333] [Impact Index Per Article: 33.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2013] [Revised: 08/01/2013] [Accepted: 01/27/2014] [Indexed: 01/01/2023]
Abstract
The cerebral hyperaemia is one of the fundamental mechanisms for the central nervous system homeostasis. Due also to this mechanism, oxygen and nutrients are maintained in satisfactory levels, through vasodilation and vasoconstriction. The brain hyperaemia, or coupling, is accomplished by a group of cells, closely related to each other; called neurovascular unit (NVU). The neurovascular unit is composed by neurones, astrocytes, endothelial cells of blood-brain barrier (BBB), myocytes, pericytes and extracellular matrix components. These cells, through their intimate anatomical and chemical relationship, detect the needs of neuronal supply and trigger necessary responses (vasodilation or vasoconstriction) for such demands. Here, we review the concepts of NVU, the coupling mechanisms and research strategies.
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Affiliation(s)
- V. Muoio
- Institut für Vegetative Physiologie; Charite- Universisitätmedizin Berlin; Berlin Germany
| | - P. B. Persson
- Institut für Vegetative Physiologie; Charite- Universisitätmedizin Berlin; Berlin Germany
| | - M. M. Sendeski
- Institut für Vegetative Physiologie; Charite- Universisitätmedizin Berlin; Berlin Germany
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Fenoy AJ, Goetz L, Chabardès S, Xia Y. Deep brain stimulation: are astrocytes a key driver behind the scene? CNS Neurosci Ther 2014; 20:191-201. [PMID: 24456263 DOI: 10.1111/cns.12223] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2013] [Revised: 12/05/2013] [Accepted: 12/07/2013] [Indexed: 01/02/2023] Open
Abstract
Despite its widespread use, the underlying mechanism of deep brain stimulation (DBS) remains unknown. Once thought to impart a "functional inactivation", there is now increasing evidence showing that DBS actually can both inhibit neurons and activate axons, generating a wide range of effects. This implies that the mechanisms that underlie DBS work not only locally but also at the network level. Therefore, not only may DBS induce membrane or synaptic plastic changes in neurons over a wide network, but it may also trigger cellular and molecular changes in other cells, especially astrocytes, where, together, the glial-neuronal interactions may explain effects that are not clearly rationalized by simple activation/inhibition theories alone. Recent studies suggest that (1) high-frequency stimulation (HFS) activates astrocytes and leads to the release of gliotransmitters that can regulate surrounding neurons at the synapse; (2) activated astrocytes modulate synaptic activity and increase axonal activation; (3) activated astrocytes can signal further astrocytes across large networks, contributing to observed network effects induced by DBS; (4) activated astrocytes can help explain the disparate effects of activation and inhibition induced by HFS at different sites; (5) astrocytes contribute to synaptic plasticity through long-term potentiation (LTP) and depression (LTD), possibly helping to mediate the long-term effects of DBS; and (6) DBS may increase delta-opioid receptor activity in astrcoytes to confer neuroprotection. Together, the plastic changes in these glial-neuronal interactions network-wide likely underlie the range of effects seen, from the variable temporal latencies to observed effect to global activation patterns. This article reviews recent research progress in the literature on how astrocytes play a key role in DBS efficacy.
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Affiliation(s)
- Albert J Fenoy
- Department of Neurosurgery, Mischer Neuroscience Institute, University of Texas Medical School at Houston, Houston, TX, USA
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37
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Ouyang YB, Xu L, Liu S, Giffard RG. Role of Astrocytes in Delayed Neuronal Death: GLT-1 and its Novel Regulation by MicroRNAs. ADVANCES IN NEUROBIOLOGY 2014; 11:171-88. [PMID: 25236729 DOI: 10.1007/978-3-319-08894-5_9] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Astrocytes have been shown to protect neurons from delayed neuronal death and increase their survival in cerebral ischemia. One of the main mechanisms of astrocyte protection is rapid removal of excess glutamate from synaptic sites by astrocytic plasma membrane glutamate transporters such as GLT-1/EAAT-2, reducing excitotoxicity. Astrocytic mitochondrial function is essential for normal GLT-1 function. Manipulating astrocytic mitochondrial and GLT-1 function is thus an important strategy to enhance neuronal survival and improve outcome following cerebral ischemia. Increasing evidence supports the involvement of microRNAs (miRNA), some of them being astrocyte-enriched, in the regulation of cerebral ischemia. This chapter will first update the information about astrocytes, GLT-1, astrocytic mitochondria, and delayed neuronal death. Then we will focus on two recently reported astrocyte-enriched miRNAs (miR-181 and miR-29 families), their effects on astrocytic mitochondria and GLT-1 as well as on outcome after cerebral ischemia.
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Affiliation(s)
- Yi-Bing Ouyang
- Department of Anesthesia, Stanford University School of Medicine, 300 Pasteur Drive, S272A and S290, Stanford, CA, 94305-5117, USA,
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Martínez D, García L, Aguilera J, Ortega A. An Acute Glutamate Exposure Induces Long-Term Down Regulation of GLAST/EAAT1 Uptake Activity in Cultured Bergmann Glia Cells. Neurochem Res 2013; 39:142-9. [DOI: 10.1007/s11064-013-1198-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2013] [Revised: 10/30/2013] [Accepted: 11/08/2013] [Indexed: 01/19/2023]
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39
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Kirischuk S, Parpura V, Verkhratsky A. Sodium dynamics: another key to astroglial excitability? Trends Neurosci 2012; 35:497-506. [PMID: 22633141 DOI: 10.1016/j.tins.2012.04.003] [Citation(s) in RCA: 172] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2012] [Revised: 04/06/2012] [Accepted: 04/10/2012] [Indexed: 11/19/2022]
Abstract
Astroglial excitability is largely mediated by fluctuations in intracellular ion concentrations. In addition to generally acknowledged Ca²⁺ excitability of astroglia, recent studies have demonstrated that neuronal activity triggers transient increases in the cytosolic Na⁺ concentration ([Na⁺](i)) in perisynaptic astrocytes. These [Na⁺](i) transients are controlled by multiple Na⁺-permeable channels and Na⁺-dependent transporters; spatiotemporally organized [Na⁺](i) dynamics in turn regulate diverse astroglial homeostatic responses such as metabolic/signaling utilization of lactate and glutamate, transmembrane transport of neurotransmitters and K⁺ buffering. In particular, near-membrane [Na⁺](i) transients determine the rate and the direction of the transmembrane transport of GABA and Ca²⁺. We discuss here the role of Na⁺ in the regulation of various systems that mediate fast bidirectional communication between neurones and glia at the single synapse level.
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Affiliation(s)
- Sergei Kirischuk
- Institute of Physiology and Pathophysiology, Universal Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
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