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Gupta P, Gupta RK, Gandhi BS, Singh P. Differential binding of CREB and REST/NRSF to NMDAR1 promoter is associated with the sex-selective cognitive deficit following postnatal PBDE-209 exposure in mice. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2024; 31:38710-38722. [PMID: 37002525 DOI: 10.1007/s11356-023-26107-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Accepted: 02/20/2023] [Indexed: 06/19/2023]
Abstract
Neonatal exposure to decabromodiphenyl ether (PBDE-209), a widely used flame retardant, affects cognitive performances in the later stage of life in a sex-dependent manner. PBDE-209 interferes with glutamatergic signaling and N-methyl-D-aspartate receptor (NMDAR) subunits with unresolved regulatory mechanisms. This study exposed male and female mice pups through postnatal day (PND) 3-10 to PBDE-209 (oral dose: 0, 6, or 20 mg/kg body weight). The frontal cortex and hippocampus, collected from neonate (PND 11) and young (PND 60) mice, were analyzed for cAMP response element-binding protein (CREB) and RE1-silencing transcription factor/ Neuron-restrictive silencer factor (REST/NRSF) binding to NMDAR1 promoter and expression of NMDAR1 gene by electrophoretic mobility shift assay and semi-quantitative RT-PCR respectively. Behavioral changes were assessed using spontaneous alternation behavior and novel object recognition tests in young mice. In neonates, the binding of CREB was increased, while REST/NRSF was decreased significantly to their cognate NMDAR1 promoter sequences at the high dose of PBDE-209 in both the sexes. This reciprocal pattern of CREB and REST/NRSF interactions correlates with the up-regulation of NMDAR1 expression. Young males followed a similar pattern of CREB and REST/NRSF binding and NMDAR1 expression as in neonates. Surprisingly, young females did not show any alteration when compared to age-matched controls. Also, we found that only young males showed working and recognition memory deficits. These results indicate that early exposure to PBDE-209 interferes with CREB- and REST/NRSF-dependent regulation of the NMDAR1 gene in an acute setting. However, long-term effects persist only in young males that could be associated with cognitive impairment.
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Affiliation(s)
- Priya Gupta
- Department of Zoology, Women's College, Banaras Hindu University, Varanasi, UP, India
| | - Rajaneesh K Gupta
- Department of Biochemistry, Institute of Science, Banaras Hindu University, Varanasi, UP, India
| | - Behrose S Gandhi
- Department of Zoology, Women's College, Banaras Hindu University, Varanasi, UP, India
| | - Poonam Singh
- Department of Zoology, Women's College, Banaras Hindu University, Varanasi, UP, India.
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2
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Mokbel AY, Burns MP, Main BS. The contribution of the meningeal immune interface to neuroinflammation in traumatic brain injury. J Neuroinflammation 2024; 21:135. [PMID: 38802931 PMCID: PMC11131220 DOI: 10.1186/s12974-024-03122-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2024] [Accepted: 05/03/2024] [Indexed: 05/29/2024] Open
Abstract
Traumatic brain injury (TBI) is a major cause of disability and mortality worldwide, particularly among the elderly, yet our mechanistic understanding of what renders the post-traumatic brain vulnerable to poor outcomes, and susceptible to neurological disease, is incomplete. It is well established that dysregulated and sustained immune responses elicit negative consequences after TBI; however, our understanding of the neuroimmune interface that facilitates crosstalk between central and peripheral immune reservoirs is in its infancy. The meninges serve as the interface between the brain and the immune system, facilitating important bi-directional roles in both healthy and disease settings. It has been previously shown that disruption of this system exacerbates neuroinflammation in age-related neurodegenerative disorders such as Alzheimer's disease; however, we have an incomplete understanding of how the meningeal compartment influences immune responses after TBI. In this manuscript, we will offer a detailed overview of the holistic nature of neuroinflammatory responses in TBI, including hallmark features observed across clinical and animal models. We will highlight the structure and function of the meningeal lymphatic system, including its role in immuno-surveillance and immune responses within the meninges and the brain. We will provide a comprehensive update on our current knowledge of meningeal-derived responses across the spectrum of TBI, and identify new avenues for neuroimmune modulation within the neurotrauma field.
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Affiliation(s)
- Alaa Y Mokbel
- Department of Neuroscience, Georgetown University Medical Center, New Research Building-EG11, 3970 Reservoir Rd, NW, Washington, DC, 20057, USA
| | - Mark P Burns
- Department of Neuroscience, Georgetown University Medical Center, New Research Building-EG11, 3970 Reservoir Rd, NW, Washington, DC, 20057, USA
| | - Bevan S Main
- Department of Neuroscience, Georgetown University Medical Center, New Research Building-EG11, 3970 Reservoir Rd, NW, Washington, DC, 20057, USA.
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3
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Janković T, Pilipović K. Single Versus Repetitive Traumatic Brain Injury: Current Knowledge on the Chronic Outcomes, Neuropathology and the Role of TDP-43 Proteinopathy. Exp Neurobiol 2023; 32:195-215. [PMID: 37749924 PMCID: PMC10569144 DOI: 10.5607/en23008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Revised: 07/18/2023] [Accepted: 08/23/2023] [Indexed: 09/27/2023] Open
Abstract
Traumatic brain injury (TBI) is one of the most important causes of death and disability in adults and thus an important public health problem. Following TBI, secondary pathophysiological processes develop over time and condition the development of different neurodegenerative entities. Previous studies suggest that neurobehavioral changes occurring after a single TBI are the basis for the development of Alzheimer's disease, while repetitive TBI is considered to be a contributing factor for chronic traumatic encephalopathy development. However, pathophysiological processes that determine the evolvement of a particular chronic entity are still unclear. Human post-mortem studies have found combinations of amyloid, tau, Lewi bodies, and TAR DNA-binding protein 43 (TDP-43) pathologies after both single and repetitive TBI. This review focuses on the pathological changes of TDP-43 after single and repetitive brain traumas. Numerous studies have shown that TDP-43 proteinopathy noticeably occurs after repetitive head trauma. A relatively small number of available preclinical research on single brain injury are not in complete agreement with the results from the human samples, which makes it difficult to draw specific conclusions. Also, as TBI is considered a heterogeneous type of injury, different experimental trauma models and injury intensities may cause differences in the cascade of secondary injury, which should be considered in future studies. Experimental and post-mortem studies of TDP-43 pathobiology should be carried out, preferably in the same laboratories, to determine its involvement in the development of neurodegenerative conditions after one and repetitive TBI, especially in the context of the development of new therapeutic options.
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Affiliation(s)
- Tamara Janković
- Department of Basic and Clinical Pharmacology and Toxicology, Faculty of Medicine, University of Rijeka, Rijeka 51000, Croatia
| | - Kristina Pilipović
- Department of Basic and Clinical Pharmacology and Toxicology, Faculty of Medicine, University of Rijeka, Rijeka 51000, Croatia
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4
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Oudart M, Avila-Gutierrez K, Moch C, Dossi E, Milior G, Boulay AC, Gaudey M, Moulard J, Lombard B, Loew D, Bemelmans AP, Rouach N, Chapat C, Cohen-Salmon M. The ribosome-associated protein RACK1 represses Kir4.1 translation in astrocytes and influences neuronal activity. Cell Rep 2023; 42:112456. [PMID: 37126448 DOI: 10.1016/j.celrep.2023.112456] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 02/10/2023] [Accepted: 04/16/2023] [Indexed: 05/02/2023] Open
Abstract
The regulation of translation in astrocytes, the main glial cells in the brain, remains poorly characterized. We developed a high-throughput proteomics screen for polysome-associated proteins in astrocytes and focused on ribosomal protein receptor of activated protein C kinase 1 (RACK1), a critical factor in translational regulation. In astrocyte somata and perisynaptic astrocytic processes (PAPs), RACK1 preferentially binds to a number of mRNAs, including Kcnj10, encoding the inward-rectifying potassium (K+) channel Kir4.1. By developing an astrocyte-specific, conditional RACK1 knockout mouse model, we show that RACK1 represses production of Kir4.1 in hippocampal astrocytes and PAPs. Upregulation of Kir4.1 in the absence of RACK1 increases astrocytic Kir4.1-mediated K+ currents and volume. It also modifies neuronal activity attenuating burst frequency and duration. Reporter-based assays reveal that RACK1 controls Kcnj10 translation through the transcript's 5' untranslated region. Hence, translational regulation by RACK1 in astrocytes represses Kir4.1 expression and influences neuronal activity.
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Affiliation(s)
- Marc Oudart
- Center for Interdisciplinary Research in Biology, College de France, CNRS, INSERM, Université PSL, Labex Memolife, Paris, France
| | - Katia Avila-Gutierrez
- Center for Interdisciplinary Research in Biology, College de France, CNRS, INSERM, Université PSL, Labex Memolife, Paris, France
| | - Clara Moch
- Laboratoire de Biochimie, Ecole Polytechnique, CNRS, Université Paris-Saclay, Palaiseau, France
| | - Elena Dossi
- Center for Interdisciplinary Research in Biology, College de France, CNRS, INSERM, Université PSL, Labex Memolife, Paris, France
| | - Giampaolo Milior
- Center for Interdisciplinary Research in Biology, College de France, CNRS, INSERM, Université PSL, Labex Memolife, Paris, France
| | - Anne-Cécile Boulay
- Center for Interdisciplinary Research in Biology, College de France, CNRS, INSERM, Université PSL, Labex Memolife, Paris, France
| | - Mathis Gaudey
- Center for Interdisciplinary Research in Biology, College de France, CNRS, INSERM, Université PSL, Labex Memolife, Paris, France
| | - Julien Moulard
- Center for Interdisciplinary Research in Biology, College de France, CNRS, INSERM, Université PSL, Labex Memolife, Paris, France
| | - Bérangère Lombard
- CurieCoreTech Spectrométrie de Masse Protéomique, Institut Curie, University PSL, Paris, France
| | - Damarys Loew
- CurieCoreTech Spectrométrie de Masse Protéomique, Institut Curie, University PSL, Paris, France
| | - Alexis-Pierre Bemelmans
- CEA, Institut de Biologie François Jacob, Molecular Imaging Research Center (MIRCen), CNRS, Université Paris-Sud, Université Paris-Saclay, Fontenay-aux-Roses, France
| | - Nathalie Rouach
- Center for Interdisciplinary Research in Biology, College de France, CNRS, INSERM, Université PSL, Labex Memolife, Paris, France
| | - Clément Chapat
- Laboratoire de Biochimie, Ecole Polytechnique, CNRS, Université Paris-Saclay, Palaiseau, France
| | - Martine Cohen-Salmon
- Center for Interdisciplinary Research in Biology, College de France, CNRS, INSERM, Université PSL, Labex Memolife, Paris, France.
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5
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Revisiting Excitotoxicity in Traumatic Brain Injury: From Bench to Bedside. Pharmaceutics 2022; 14:pharmaceutics14010152. [PMID: 35057048 PMCID: PMC8781803 DOI: 10.3390/pharmaceutics14010152] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Revised: 12/31/2021] [Accepted: 01/05/2022] [Indexed: 12/12/2022] Open
Abstract
Traumatic brain injury (TBI) is one of the leading causes of morbidity and mortality. Consequences vary from mild cognitive impairment to death and, no matter the severity of subsequent sequelae, it represents a high burden for affected patients and for the health care system. Brain trauma can cause neuronal death through mechanical forces that disrupt cell architecture, and other secondary consequences through mechanisms such as inflammation, oxidative stress, programmed cell death, and, most importantly, excitotoxicity. This review aims to provide a comprehensive understanding of the many classical and novel pathways implicated in tissue damage following TBI. We summarize the preclinical evidence of potential therapeutic interventions and describe the available clinical evaluation of novel drug targets such as vitamin B12 and ifenprodil, among others.
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6
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Mira RG, Lira M, Cerpa W. Traumatic Brain Injury: Mechanisms of Glial Response. Front Physiol 2021; 12:740939. [PMID: 34744783 PMCID: PMC8569708 DOI: 10.3389/fphys.2021.740939] [Citation(s) in RCA: 67] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Accepted: 09/20/2021] [Indexed: 11/17/2022] Open
Abstract
Traumatic brain injury (TBI) is a heterogeneous disorder that involves brain damage due to external forces. TBI is the main factor of death and morbidity in young males with a high incidence worldwide. TBI causes central nervous system (CNS) damage under a variety of mechanisms, including synaptic dysfunction, protein aggregation, mitochondrial dysfunction, oxidative stress, and neuroinflammation. Glial cells comprise most cells in CNS, which are mediators in the brain’s response to TBI. In the CNS are present astrocytes, microglia, oligodendrocytes, and polydendrocytes (NG2 cells). Astrocytes play critical roles in brain’s ion and water homeostasis, energy metabolism, blood-brain barrier, and immune response. In response to TBI, astrocytes change their morphology and protein expression. Microglia are the primary immune cells in the CNS with phagocytic activity. After TBI, microglia also change their morphology and release both pro and anti-inflammatory mediators. Oligodendrocytes are the myelin producers of the CNS, promoting axonal support. TBI causes oligodendrocyte apoptosis, demyelination, and axonal transport disruption. There are also various interactions between these glial cells and neurons in response to TBI that contribute to the pathophysiology of TBI. In this review, we summarize several glial hallmarks relevant for understanding the brain injury and neuronal damage under TBI conditions.
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Affiliation(s)
- Rodrigo G Mira
- Laboratorio de Función y Patología Neuronal, Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Matías Lira
- Laboratorio de Función y Patología Neuronal, Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Waldo Cerpa
- Laboratorio de Función y Patología Neuronal, Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile.,Centro de Excelencia en Biomedicina de Magallanes (CEBIMA), Universidad de Magallanes, Punta Arenas, Chile
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7
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Götz S, Bribian A, López-Mascaraque L, Götz M, Grothe B, Kunz L. Heterogeneity of astrocytes: Electrophysiological properties of juxtavascular astrocytes before and after brain injury. Glia 2020; 69:346-361. [PMID: 32809228 DOI: 10.1002/glia.23900] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 07/20/2020] [Accepted: 07/30/2020] [Indexed: 12/31/2022]
Abstract
Astrocyte heterogeneity is increasingly recognized, but still little is known about juxtavascular astrocytes with their somata directly adjacent to blood vessels, despite their importance after brain injury. As juxtavascular astrocytes originate from common progenitor cells, that is, have a clonal origin, they may intrinsically differ from other, non-juxtavascular astrocytes. To explore this, we examined the electrophysiological properties of these groups of astrocytes and the underlying ion channels. Using brain slices of BAC Aldh1l1-eGFP transgenic mice with astrocytes labeled by GFP expression, we compared juxtavascular and non-juxtavascular astrocytes in the somatosensory cortex by means of whole-cell patch-clamp recordings and immunohistochemical staining. Prior to injury, juxta- and non-juxtavascular astrocytes exhibit comparable electrophysiological properties with characteristic mostly passive conductance and a typical negative resting membrane potential. Immunohistochemical analysis of K+ channels showed that all astrocytes were Kir 4.1+ , but revealed an intriguing difference for Kv 4.3. The expression of Kv 4.3 in sibling astrocytes (non-juxtavascular, juxtavascular and pial) was dependent on their ontogenetic origin with lowest levels in juxtavascular astrocytes located in upper cortical layers. After traumatic brain injury (TBI), we found profound changes in the electrophysiological type of astrocytes with a predominance of non-passive properties and this pattern was significantly enriched in juxtavascular astrocytes. This was accompanied by pronounced down-regulation of Kir 4.1 in proliferating astrocytes, which was significantly more in juxtavascular compared to non-juxtavascular astrocytes. Taken together, TBI induces profound differences in electrophysiological properties between juxtavascular and non-juxtavascular astrocytes that might be related to the preponderance of juxtavascular astrocyte proliferation.
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Affiliation(s)
- Stefanie Götz
- Division of Neurobiology, Department of Biology II, Ludwig-Maximilians-Universitaet (LMU) Munich, Martinsried, Germany.,Graduate School of Systemic Neurosciences, Ludwig-Maximilians-Universitaet (LMU) Munich, Martinsried, Germany.,Biomedical Center (BMC), Ludwig-Maximilians-Universitaet (LMU) Munich, SyNergy - Munich Cluster for Systems Neurology, Munich, Germany
| | - Ana Bribian
- Instituto Cajal-CSIC, Molecular, Cellular and Developmental Neurobiology Department, Madrid, Spain
| | - Laura López-Mascaraque
- Instituto Cajal-CSIC, Molecular, Cellular and Developmental Neurobiology Department, Madrid, Spain
| | - Magdalena Götz
- Biomedical Center (BMC), Ludwig-Maximilians-Universitaet (LMU) Munich, SyNergy - Munich Cluster for Systems Neurology, Munich, Germany.,Physiological Genomics, Biomedical Center (BMC), Ludwig-Maximilians-Universitaet (LMU) Munich, Martinsried, Germany.,Institute of Stem Cell Research, Helmholtz Center Munich, German Research Center for Environmental Health, Martinsried, Germany
| | - Benedikt Grothe
- Division of Neurobiology, Department of Biology II, Ludwig-Maximilians-Universitaet (LMU) Munich, Martinsried, Germany.,Biomedical Center (BMC), Ludwig-Maximilians-Universitaet (LMU) Munich, SyNergy - Munich Cluster for Systems Neurology, Munich, Germany
| | - Lars Kunz
- Division of Neurobiology, Department of Biology II, Ludwig-Maximilians-Universitaet (LMU) Munich, Martinsried, Germany
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8
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Boni JL, Kahanovitch U, Nwaobi SE, Floyd CL, Olsen ML. DNA methylation: A mechanism for sustained alteration of KIR4.1 expression following central nervous system insult. Glia 2020; 68:1495-1512. [PMID: 32068308 PMCID: PMC8665281 DOI: 10.1002/glia.23797] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Revised: 01/29/2020] [Accepted: 01/31/2020] [Indexed: 12/22/2022]
Abstract
Kir4.1, a glial-specific inwardly rectifying potassium channel, is implicated in astrocytic maintenance of K+ homeostasis. Underscoring the role of Kir4.1 in central nervous system (CNS) functioning, genetic mutations in KCNJ10, the gene which encodes Kir4.1, causes seizures, ataxia and developmental disability in humans. Kir4.1 protein and mRNA loss are consistently observed in CNS injury and neurological diseases linked to hyperexcitability and neuronal dysfunction, leading to the notion that Kir4.1 represents an attractive therapeutic target. Despite this, little is understood regarding the mechanisms that underpin this downregulation. Previous work by our lab revealed that DNA hypomethylation of the Kcnj10 gene functions to regulate mRNA levels during astrocyte maturation whereas hypermethylation in vitro led to decreased promoter activity. In the present study, we utilized two vastly different injury models with known acute and chronic loss of Kir4.1 protein and mRNA to evaluate the methylation status of Kcnj10 as a candidate molecular mechanism for reduced transcription and subsequent protein loss. Examining whole hippocampal tissue and isolated astrocytes, in a lithium-pilocarpine model of epilepsy, we consistently identified hypermethylation of CpG island two, which resides in the large intronic region spanning the Kcnj10 gene. Strikingly similar results were observed using the second injury paradigm, a fifth cervical (C5) vertebral hemi-contusion model of spinal cord injury. Our previous work indicates the same gene region is significantly hypomethylated when transcription increases during astrocyte maturation. Our results suggest that DNA methylation can bidirectionally modulate Kcnj10 transcription and may represent a targetable molecular mechanism for the restoring astroglial Kir4.1 expression following CNS insult.
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Affiliation(s)
- Jessica L Boni
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama
- School of Neuroscience, Virginia Polytechnic and State University, Blacksburg, Virginia
| | - Uri Kahanovitch
- School of Neuroscience, Virginia Polytechnic and State University, Blacksburg, Virginia
| | - Sinifunanya E Nwaobi
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama
- Division of Pediatric Neurology, UCLA Mattel Children's Hospital, University of California Los Angeles, Los Angeles, California
| | - Candace L Floyd
- Department of Physical Medicine and Rehabilitation, University of Alabama at Birmingham, Birmingham, Alabama
- Department of Physical Medicine and Rehabilitation, University of Utah Health, Salt Lake City, Utah
| | - Michelle L Olsen
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama
- School of Neuroscience, Virginia Polytechnic and State University, Blacksburg, Virginia
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9
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Zhou Y, Shao A, Yao Y, Tu S, Deng Y, Zhang J. Dual roles of astrocytes in plasticity and reconstruction after traumatic brain injury. Cell Commun Signal 2020; 18:62. [PMID: 32293472 PMCID: PMC7158016 DOI: 10.1186/s12964-020-00549-2] [Citation(s) in RCA: 90] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Accepted: 03/06/2020] [Indexed: 12/14/2022] Open
Abstract
Traumatic brain injury (TBI) is one of the leading causes of fatality and disability worldwide. Despite its high prevalence, effective treatment strategies for TBI are limited. Traumatic brain injury induces structural and functional alterations of astrocytes, the most abundant cell type in the brain. As a way of coping with the trauma, astrocytes respond in diverse mechanisms that result in reactive astrogliosis. Astrocytes are involved in the physiopathologic mechanisms of TBI in an extensive and sophisticated manner. Notably, astrocytes have dual roles in TBI, and some astrocyte-derived factors have double and opposite properties. Thus, the suppression or promotion of reactive astrogliosis does not have a substantial curative effect. In contrast, selective stimulation of the beneficial astrocyte-derived molecules and simultaneous attenuation of the deleterious factors based on the spatiotemporal-environment can provide a promising astrocyte-targeting therapeutic strategy. In the current review, we describe for the first time the specific dual roles of astrocytes in neuronal plasticity and reconstruction, including neurogenesis, synaptogenesis, angiogenesis, repair of the blood-brain barrier, and glial scar formation after TBI. We have also classified astrocyte-derived factors depending on their neuroprotective and neurotoxic roles to design more appropriate targeted therapies. Video Abstract
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Affiliation(s)
- Yunxiang Zhou
- Department of Surgical Oncology, The Second Affiliated Hospital, Zhejiang University School of Medicine, No. 88, Jiefang Road, Zhejiang, 310009, Hangzhou, China
| | - Anwen Shao
- Department of Neurosurgery, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Province, Zhejiang, 310009, Hangzhou, China.
| | - Yihan Yao
- Department of Surgical Oncology, The Second Affiliated Hospital, Zhejiang University School of Medicine, No. 88, Jiefang Road, Zhejiang, 310009, Hangzhou, China
| | - Sheng Tu
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, College of Medicine, Zhejiang University, Zhejiang, Hangzhou, China
| | - Yongchuan Deng
- Department of Surgical Oncology, The Second Affiliated Hospital, Zhejiang University School of Medicine, No. 88, Jiefang Road, Zhejiang, 310009, Hangzhou, China
| | - Jianmin Zhang
- Department of Neurosurgery, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Province, Zhejiang, 310009, Hangzhou, China
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10
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Iboaya A, Harris JL, Arickx AN, Nudo RJ. Models of Traumatic Brain Injury in Aged Animals: A Clinical Perspective. Neurorehabil Neural Repair 2019; 33:975-988. [PMID: 31722616 PMCID: PMC6920554 DOI: 10.1177/1545968319883879] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Traumatic brain injury (TBI) is a major cause of morbidity and mortality in the United States, with advanced age being one of the major predictors of poor prognosis. To replicate the mechanisms and multifaceted complexities of human TBI and develop prospective therapeutic treatments, various TBI animal models have been developed. These models have been essential in furthering our understanding of the pathophysiology and biochemical effects on brain mechanisms following TBI. Despite these advances, translating preclinical results to clinical application, particularly in elderly individuals, continues to be challenging. This review aims to provide a clinical perspective, identifying relevant variables currently not replicated in TBI animal models, to potentially improve translation to clinical practice, especially as it applies to elderly populations. As background for this clinical perspective, we reviewed articles indexed on PubMed from 1970 to 2019 that used aged animal models for studying TBI. These studies examined end points relevant for clinical translation, such as neurocognitive effects, sensorimotor behavior, physiological mechanisms, and efficacy of neuroprotective therapies. However, compared with the higher incidence of TBI in older individuals, animal studies on the basic science of aging and TBI remain remarkably scarce. Moreover, a fundamental disconnect remains between experiments in animal models of TBI and successful translation of findings for treating the older TBI population. In this article, we aim to provide a clinical perspective on the unique attributes of TBI in older individuals and a critical appraisal of the research to date on TBI in aged animal models as well as recommendations for future studies.
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Affiliation(s)
- Aiwane Iboaya
- University of Kansas Medical Center, Kansas City, KS, USA
| | - Janna L Harris
- University of Kansas Medical Center, Kansas City, KS, USA
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Neuroinflammation in Post-Traumatic Epilepsy: Pathophysiology and Tractable Therapeutic Targets. Brain Sci 2019; 9:brainsci9110318. [PMID: 31717556 PMCID: PMC6895909 DOI: 10.3390/brainsci9110318] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Revised: 10/31/2019] [Accepted: 11/08/2019] [Indexed: 02/06/2023] Open
Abstract
Epilepsy is a common chronic consequence of traumatic brain injury (TBI), contributing to increased morbidity and mortality for survivors. As post-traumatic epilepsy (PTE) is drug-resistant in at least one-third of patients, there is a clear need for novel therapeutic strategies to prevent epilepsy from developing after TBI, or to mitigate its severity. It has long been recognized that seizure activity is associated with a local immune response, characterized by the activation of microglia and astrocytes and the release of a plethora of pro-inflammatory cytokines and chemokines. More recently, increasing evidence also supports a causal role for neuroinflammation in seizure induction and propagation, acting both directly and indirectly on neurons to promote regional hyperexcitability. In this narrative review, we focus on key aspects of the neuroinflammatory response that have been implicated in epilepsy, with a particular focus on PTE. The contributions of glial cells, blood-derived leukocytes, and the blood–brain barrier will be explored, as well as pro- and anti-inflammatory mediators. While the neuroinflammatory response to TBI appears to be largely pro-epileptogenic, further research is needed to clearly demonstrate causal relationships. This research has the potential to unveil new drug targets for PTE, and identify immune-based biomarkers for improved epilepsy prediction.
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12
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Liu T, Li G, Noble KV, Li Y, Barth JL, Schulte BA, Lang H. Age-dependent alterations of Kir4.1 expression in neural crest-derived cells of the mouse and human cochlea. Neurobiol Aging 2019; 80:210-222. [PMID: 31220650 PMCID: PMC6679794 DOI: 10.1016/j.neurobiolaging.2019.04.009] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2018] [Revised: 04/02/2019] [Accepted: 04/11/2019] [Indexed: 11/18/2022]
Abstract
Age-related hearing loss (or presbyacusis) is a progressive pathophysiological process. This study addressed the hypothesis that degeneration/dysfunction of multiple nonsensory cell types contributes to presbyacusis by evaluating tissues obtained from young and aged CBA/CaJ mouse ears and human temporal bones. Ultrastructural examination and transcriptomic analysis of mouse cochleas revealed age-dependent pathophysiological alterations in 3 types of neural crest-derived cells, namely intermediate cells in the stria vascularis, outer sulcus cells in the cochlear lateral wall, and satellite cells in the spiral ganglion. A significant decline in immunoreactivity for Kir4.1, an inwardly rectifying potassium channel, was seen in strial intermediate cells and outer sulcus cells in the ears of older mice. Age-dependent alterations in Kir4.1 immunostaining also were observed in satellite cells ensheathing spiral ganglion neurons. Expression alterations of Kir4.1 were observed in these same cell populations in the aged human cochlea. These results suggest that degeneration/dysfunction of neural crest-derived cells maybe an important contributing factor to both metabolic and neural forms of presbyacusis.
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Affiliation(s)
- Ting Liu
- Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston, SC, USA; Department of Otolaryngology Head and Neck Surgery, Beijing Tongren Hospital, Capital Medical University, Key Laboratory of Otolaryngology Head and Neck Surgery, Ministry of Education, Beijing, China
| | - Gang Li
- Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston, SC, USA; Department of Otolaryngology, Tinnitus and Hyperacusis Center, Yueyang Hospital of Integrated Traditional Chinese and Western Medicine Affiliated to Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Kenyaria V Noble
- Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston, SC, USA
| | - Yongxi Li
- Department of Otolaryngology Head and Neck Surgery, Beijing Tongren Hospital, Capital Medical University, Key Laboratory of Otolaryngology Head and Neck Surgery, Ministry of Education, Beijing, China
| | - Jeremy L Barth
- Department of Regenerative Medicine, Medical University of South Carolina, Charleston, SC, USA
| | - Bradley A Schulte
- Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston, SC, USA; Department of Otolaryngology-Head and Neck Surgery, Medical University of South Carolina, Charleston, SC, USA
| | - Hainan Lang
- Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston, SC, USA.
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13
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Chen M, Luo C, Zhao J, Devarajan G, Xu H. Immune regulation in the aging retina. Prog Retin Eye Res 2018; 69:159-172. [PMID: 30352305 DOI: 10.1016/j.preteyeres.2018.10.003] [Citation(s) in RCA: 144] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Revised: 10/13/2018] [Accepted: 10/19/2018] [Indexed: 12/24/2022]
Abstract
The retina is an immune privileged tissue, which is protected from external and internal insults by its blood-retina barriers and immune suppressive microenvironment. Apart from the avoidance and tolerance strategies, the retina is also protected by its own defense system, i.e., microglia and the complement system. The immune privilege and defense mechanisms work together to maintain retinal homeostasis. During aging, the retina is at an increased risk of developing various degenerative diseases such as age-related macular degeneration, diabetic retinopathy, and glaucomatous retinopathy. Previously, we have shown that aging induces a para-inflammatory response in the retina. In this review, we explore the impact of aging on retinal immune regulation and the connection between homeostatic control of retinal immune privilege and para-inflammation under aging conditions and present a view that may explain why aging puts the retina at risk of developing degenerative diseases.
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Affiliation(s)
- Mei Chen
- Centre for Experimental Medicine, School of Medicine, Dentistry & Biomedical Sciences, Queen's University Belfast, UK
| | - Chang Luo
- Centre for Experimental Medicine, School of Medicine, Dentistry & Biomedical Sciences, Queen's University Belfast, UK; Aier Eye Institute, Aier School of Ophthalmology, Central South University, China
| | - Jiawu Zhao
- Centre for Experimental Medicine, School of Medicine, Dentistry & Biomedical Sciences, Queen's University Belfast, UK
| | | | - Heping Xu
- Centre for Experimental Medicine, School of Medicine, Dentistry & Biomedical Sciences, Queen's University Belfast, UK; Aier Eye Institute, Aier School of Ophthalmology, Central South University, China.
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14
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Susceptibility of the cerebral cortex to spreading depolarization in neurological disease states: The impact of aging. Neurochem Int 2018; 127:125-136. [PMID: 30336178 DOI: 10.1016/j.neuint.2018.10.010] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Revised: 10/10/2018] [Accepted: 10/13/2018] [Indexed: 12/17/2022]
Abstract
Secondary injury following acute brain insults significantly contributes to poorer neurological outcome. The spontaneous, recurrent occurrence of spreading depolarization events (SD) has been recognized as a potent secondary injury mechanism in subarachnoid hemorrhage, malignant ischemic stroke and traumatic brain injury. In addition, SD is the underlying mechanism of the aura symptoms of migraineurs. The susceptibility of the nervous tissue to SD is subject to the metabolic status of the tissue, the ionic composition of the extracellular space, and the functional status of ion pumps, voltage-gated and other cation channels, glutamate receptors and excitatory amino acid transporters. All these mechanisms tune the excitability of the nervous tissue. Aging has also been found to alter SD susceptibility, which appears to be highest at young adulthood, and decline over the aging process. The lower susceptibility of the cerebral gray matter to SD in the old brain may be caused by the age-related impairment of mechanisms implicated in ion translocations between the intra- and extracellular compartments, glutamate signaling and surplus potassium and glutamate clearance. Even though the aging nervous tissue is thus less able to sustain SD, the consequences of SD recurrence in the old brain have proven to be graver, possibly leading to accelerated lesion maturation. Taken that recurrent SDs may pose an increased burden in the aging injured brain, the benefit of therapeutic approaches to restrict SD generation and propagation may be particularly relevant for elderly patients.
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Abstract
Epilepsy is among the most prevalent chronic neurological diseases and affects an estimated 2.2 million people in the United States alone. About one third of patients are resistant to currently available antiepileptic drugs, which are exclusively targeting neuronal function. Yet, reactive astrocytes have emerged as potential contributors to neuronal hyperexcitability and seizures. Astrocytes react to any kind of CNS insult with a range of cellular adjustments to form a scar and protect uninjured brain regions. This process changes astrocyte physiology and can affect neuronal network function in various ways. Traumatic brain injury and stroke, both conditions that trigger astroglial scar formation, are leading causes of acquired epilepsies and surgical removal of this glial scar in patients with drug-resistant epilepsy can alleviate the seizures. This review will summarize the currently available evidence suggesting that epilepsy is not a disease of neurons alone, but that astrocytes, glial cells in the brain, can be major contributors to the disease, especially when they adopt a reactive state in response to central nervous system insult.
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Affiliation(s)
- Stefanie Robel
- Virginia Tech Carilion Research Institute, Roanoke, VA, USA
- Virginia Tech School of Neuroscience, Blacksburg, VA, USA
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16
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Dorsett CR, McGuire JL, DePasquale EAK, Gardner AE, Floyd CL, McCullumsmith RE. Glutamate Neurotransmission in Rodent Models of Traumatic Brain Injury. J Neurotrauma 2016; 34:263-272. [PMID: 27256113 DOI: 10.1089/neu.2015.4373] [Citation(s) in RCA: 86] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Traumatic brain injury (TBI) is a leading cause of death and disability in people younger than 45 and is a significant public health concern. In addition to primary mechanical damage to cells and tissue, TBI involves additional molecular mechanisms of injury, termed secondary injury, that continue to evolve over hours, days, weeks, and beyond. The trajectory of recovery after TBI is highly unpredictable and in many cases results in chronic cognitive and behavioral changes. Acutely after TBI, there is an unregulated release of glutamate that cannot be buffered or cleared effectively, resulting in damaging levels of glutamate in the extracellular space. This initial loss of glutamate homeostasis may initiate additional changes in glutamate regulation. The excitatory amino acid transporters (EAATs) are expressed on both neurons and glia and are the principal mechanism for maintaining extracellular glutamate levels. Diffusion of glutamate outside the synapse due to impaired uptake may lead to increased extrasynaptic glutamate signaling, secondary injury through activation of cell death pathways, and loss of fidelity and specificity of synaptic transmission. Coordination of glutamate release and uptake is critical to regulating synaptic strength, long-term potentiation and depression, and cognitive processes. In this review, we will discuss dysregulation of extracellular glutamate and glutamate uptake in the acute stage of TBI and how failure to resolve acute disruptions in glutamate homeostatic mechanisms may play a causal role in chronic cognitive symptoms after TBI.
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Affiliation(s)
- Christopher R Dorsett
- 1 Biological and Biomedical Sciences Doctoral Program, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina
| | - Jennifer L McGuire
- 2 Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati , Cincinnati, Ohio
| | - Erica A K DePasquale
- 2 Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati , Cincinnati, Ohio
| | - Amanda E Gardner
- 2 Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati , Cincinnati, Ohio
| | - Candace L Floyd
- 3 Department of Physical Medicine and Rehabilitation, University of Alabama at Birmingham , Birmingham, Alabama
| | - Robert E McCullumsmith
- 2 Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati , Cincinnati, Ohio
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Rivera-Aponte DE, Méndez-González MP, Rivera-Pagán AF, Kucheryavykh YV, Kucheryavykh LY, Skatchkov SN, Eaton MJ. Hyperglycemia reduces functional expression of astrocytic Kir4.1 channels and glial glutamate uptake. Neuroscience 2015; 310:216-23. [PMID: 26404875 DOI: 10.1016/j.neuroscience.2015.09.044] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Revised: 09/11/2015] [Accepted: 09/18/2015] [Indexed: 11/24/2022]
Abstract
Diabetics are at risk for a number of serious health complications including an increased incidence of epilepsy and poorer recovery after ischemic stroke. Astrocytes play a critical role in protecting neurons by maintaining extracellular homeostasis and preventing neurotoxicity through glutamate uptake and potassium buffering. These functions are aided by the presence of potassium channels, such as Kir4.1 inwardly rectifying potassium channels, in the membranes of astrocytic glial cells. The purpose of the present study was to determine if hyperglycemia alters Kir4.1 potassium channel expression and homeostatic functions of astrocytes. We used q-PCR, Western blot, patch-clamp electrophysiology studying voltage and potassium step responses and a colorimetric glutamate clearance assay to assess Kir4.1 channel levels and homeostatic functions of rat astrocytes grown in normal and high glucose conditions. We found that astrocytes grown in high glucose (25 mM) had an approximately 50% reduction in Kir4.1 mRNA and protein expression as compared with those grown in normal glucose (5mM). These reductions occurred within 4-7 days of exposure to hyperglycemia, whereas reversal occurred between 7 and 14 days after return to normal glucose. The decrease in functional Kir channels in the astrocytic membrane was confirmed using barium to block Kir channels. In the presence of 100-μM barium, the currents recorded from astrocytes in response to voltage steps were reduced by 45%. Furthermore, inward currents induced by stepping extracellular [K(+)]o from 3 to 10mM (reflecting potassium uptake) were 50% reduced in astrocytes grown in high glucose. In addition, glutamate clearance by astrocytes grown in high glucose was significantly impaired. Taken together, our results suggest that down-regulation of astrocytic Kir4.1 channels by elevated glucose may contribute to the underlying pathophysiology of diabetes-induced CNS disorders and contribute to the poor prognosis after stroke.
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Affiliation(s)
- D E Rivera-Aponte
- Department of Biochemistry, Universidad Central del Caribe, Bayamón, PR, USA.
| | - M P Méndez-González
- Department of Biochemistry, Universidad Central del Caribe, Bayamón, PR, USA.
| | - A F Rivera-Pagán
- Department of Biochemistry, Universidad Central del Caribe, Bayamón, PR, USA.
| | - Y V Kucheryavykh
- Department of Biochemistry, Universidad Central del Caribe, Bayamón, PR, USA.
| | - L Y Kucheryavykh
- Department of Biochemistry, Universidad Central del Caribe, Bayamón, PR, USA.
| | - S N Skatchkov
- Department of Biochemistry, Universidad Central del Caribe, Bayamón, PR, USA; Department of Physiology, Universidad Central del Caribe, Bayamón, PR, USA.
| | - M J Eaton
- Department of Biochemistry, Universidad Central del Caribe, Bayamón, PR, USA.
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18
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Thrombin decreases expression of the glutamate transporter GLAST and inhibits glutamate uptake in primary cortical astrocytes via the Rho kinase pathway. Exp Neurol 2015; 273:288-300. [PMID: 26391563 DOI: 10.1016/j.expneurol.2015.09.009] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Accepted: 09/17/2015] [Indexed: 01/08/2023]
Abstract
Astrocyte glutamate transporters GLAST and GLT1 play a key role in regulating neuronal excitation and their levels are altered in patients with epilepsy, and after traumatic brain injury. The mechanisms which regulate their expression are not well understood. We tested the hypothesis that exposure of astrocytes to high levels of thrombin, as may occur after a compromise of the blood-brain barrier, would reduce astrocyte glutamate transporter levels. In isolated rat cortical astrocytes we examined the effects of thrombin on the expression and function of glutamate transporters, and the signaling pathways involved in these responses by using Western blotting and selective inhibitors. Thrombin induced a selective decrease in the expression of GLAST but not GLT1, with a corresponding decrease in the capacity of astrocytes to take up glutamate. Activation of the thrombin receptor PAR-1 with an activating peptide induced a similar decrease in the expression of GLAST and compromise of glutamate uptake. The downregulation of GLAST induced by thrombin was mediated by the mitogen activated protein kinases p38 MAPK, ERK and JNK, but inhibition of these kinases did not prevent the decrease in glutamate uptake induced by thrombin. In contrast, inhibition of the Rho kinase pathway using the specific inhibitor, Y27632, suppressed both the decrease in the expression of GLAST and the decrease in glutamate uptake induced by thrombin. In hippocampal astrocyte cultures, thrombin caused a decrease in both GLAST and GLT1. In tissue resected from brains of children with intractable epilepsy, we found a decrease in the integrity of the blood-brain barrier along with a reduction in immunoreactivity for both transporters which was associated with an increase in cleaved thrombin and reactive astrogliosis. The in vitro results suggest a specific mechanism by which thrombin may lead to a compromise of astrocyte function and enhanced synaptic excitability after the blood-brain barrier is compromised. The human in vivo results provide indirect support evidence linking the compromise of the blood-brain barrier to thrombin-induced reduction in glutamate transporter expression and an increase in neuronal excitation.
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19
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CDRI-08 Attenuates REST/NRSF-Mediated Expression of NMDAR1 Gene in PBDE-209-Exposed Mice Brain. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2015; 2015:403840. [PMID: 26413122 PMCID: PMC4564648 DOI: 10.1155/2015/403840] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Revised: 02/16/2015] [Accepted: 02/22/2015] [Indexed: 11/17/2022]
Abstract
CDRI-08 is a standardized bacoside enriched ethanolic extract of Bacopa monnieri, a nootropic plant. We reported that CDRI-08 attenuated oxidative stress and memory impairment in mice, induced by a flame retardant, PBDE-209. In order to explore the mechanism, present study was designed to examine the role of CDRI-08 on the expression of NMDAR1 (NR1) and the binding of REST/NRSF to NR1 promoter against postnatal exposure of PBDE-209. Male mice pups were orally supplemented with CDRI-08 at the doses of 40, 80, or 120 mg/kg along with PBDE-209 (20 mg/kg) during PND 3–10 and frontal cortex and hippocampus were collected at PND 11 and 60 to study the expression and regulation of NR1 by RT-PCR and electrophoretic mobility shift assay, respectively. The findings showed upregulated expression of NR1 and decreased binding of REST/NRSF to NR1 promoter after postnatal exposure of PBDE-209. Interestingly, supplementation with CDRI-08 significantly restored the expression of NR1 and binding of REST/NRSF to NR1 promoter near to the control value at the dose of 120 mg/kg. In conclusion, the results suggest that CDRI-08 possibly acts on glutamatergic system through expression and regulation of NR1 and may restore memory, impaired by PBDE-209 as reported in our previous study.
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Gupta RK, Prasad S. Age-Dependent Alterations in the Interactions of NF-κB and N-myc with GLT-1/EAAT2 Promoter in the Pericontusional Cortex of Mice Subjected to Traumatic Brain Injury. Mol Neurobiol 2015; 53:3377-3388. [PMID: 26081154 DOI: 10.1007/s12035-015-9287-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Accepted: 06/03/2015] [Indexed: 01/09/2023]
Abstract
Traumatic brain injury (TBI) is one of the major risk factors of dementia, aging, and cognitive impairments, etc. We have previously reported that expression of the astrocytic glutamate transporter GLT-1/EAAT2 is downregulated in the pericontusional cortex of adult and old mice in post-TBI time-dependent manner, and the process of decline starts before in old than in adult TBI mice. However, relationship between age- and TBI-dependent alterations in GLT-1/EAAT2 expression and interactions of transcription factors NF-κB and N-myc with their cognate GLT-1/EAAT2 promoter sequences, an important step of its transcriptional control, is not known. To understand this, we developed TBI mouse model by modified chronic head injury (CHI) method, analyzed expression of GFAP, TNF-α, and AQP4 by RT-PCR for its validation, and analyzed interactions of NF-κB and N-myc with GLT-1/EAAT2 promoter sequences by electrophoretic mobility shift assay (EMSA). Our EMSA data revealed that interactions of NF-κB and N-myc with GLT-1/EAAT2 promoter sequences was significantly elevated in the ipsi-lateral cortex of both adult and old TBI mice in post-TBI time-dependent manner; however, these interactions started immediately in the old compared to that in adult TBI mice, which could be attributed to our previously reported age- and post-TBI time-dependent differential expression of GLT-1/EAAT2 in the pericontusional cortex.
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Affiliation(s)
- Rajaneesh K Gupta
- Biochemistry and Molecular Biology Laboratory, Department of Zoology, Banaras Hindu University, Varanasi, 221005, UP, India
| | - S Prasad
- Biochemistry and Molecular Biology Laboratory, Department of Zoology, Banaras Hindu University, Varanasi, 221005, UP, India.
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21
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Pandey SP, Rai R, Gaur P, Prasad S. Development- and age-related alterations in the expression of AMPA receptor subunit GluR2 and its trafficking proteins in the hippocampus of male mouse brain. Biogerontology 2015; 16:317-28. [DOI: 10.1007/s10522-014-9548-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2014] [Accepted: 12/16/2014] [Indexed: 10/24/2022]
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Poulose N, Raju R. Aging and injury: alterations in cellular energetics and organ function. Aging Dis 2014; 5:101-8. [PMID: 24729935 DOI: 10.14336/ad.2014.0500101] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2014] [Revised: 03/13/2014] [Accepted: 03/13/2014] [Indexed: 12/16/2022] Open
Abstract
Aging is characterized by increased oxidative stress, heightened inflammatory response, accelerated cellular senescence and progressive organ dysfunction. The homeostatic imbalance with aging significantly alters cellular responses to injury. Though it is unclear whether cellular energetic imbalance is a cause or effect of the aging process, preservation of mitochondrial function has been reported to be important in organ function restoration following severe injury. Unintentional injuries are ranked among the top 10 causes of death in adults of both sexes, 65 years and older. Aging associated decline in mitochondrial function has been shown to enhance the vulnerability of heart, lung, liver and kidney to ischemia/reperfusion injury. Studies have identified alterations in the level or activity of factors such as SIRT1, PGC-1α, HIF-1α and c-MYC involved in key regulatory processes in the maintenance of mitochondrial structural integrity, biogenesis and function. Studies using experimental models of hemorrhagic injury and burn have demonstrated significant influence of aging in metabolic regulation and organ function. Understanding the age-associated molecular mechanisms regulating mitochondrial dysfunction following injury is important towards identifying novel targets and therapeutic strategies to improve the outcome after injury in the elderly.
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Affiliation(s)
| | - Raghavan Raju
- Department of Medical Laboratory, Imaging and Radiological Sciences, Georgia Regents University, Augusta, GA30912, USA ; Biochemistry and Molecular Biology, Georgia Regents University, Augusta, GA30912, USA
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Gupta RK, Prasad S. Differential regulation of GLT-1/EAAT2 gene expression by NF-κB and N-myc in male mouse brain during postnatal development. Neurochem Res 2013; 39:150-60. [PMID: 24277080 DOI: 10.1007/s11064-013-1200-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2013] [Revised: 11/06/2013] [Accepted: 11/13/2013] [Indexed: 12/14/2022]
Abstract
The synaptic glutamate level homeostasis is mainly maintained by the astrocytes membrane bound glutamate transporter type-1 (GLT-1/EAAT2). Alterations in its expression during development and aging and the underlying mechanisms are not well studied. Here, we report that NF-κB interaction was highest in both cerebral and cerebellar cortices at day 15 when compared with that at day 0 during development, and it further declined significantly in day 45, and remained unchanged in 20 and 70 weeks mice. On the other hand, N-myc interaction was highest at 0 day which significantly declined at 15-day and interestingly remained unaltered at later ages in both the cortices. This age dependent reciprocal pattern of NF-κB and N-myc interactions with their cognate GLT-1 promoter sequences was further correlated with GLT-1 protein and transcript levels. We found that higher NF-κB interaction with its cognate GLT-1 promoter sequences correlates with up-regulation whereas the higher N-myc interaction correlates with down-regulation of GLT-1 expression during postnatal developmental age up to 15 day, however, such phenomenon was not found in the higher ages from day 45 to 70 weeks. Thus our data suggests a postnatal development- and age dependent differential interaction of transcription factors NF-κB and N-myc to their respective sequences and they act as positive and negative regulator, respectively of GLT-1 gene expression in the brain during early developmental period in both cerebral and cerebellar cortices which might be different in aging of mice.
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Affiliation(s)
- Rajaneesh Kumar Gupta
- Molecular Biology and Biochemistry Lab., Centre of Advanced Study in Zoology, Banaras Hindu University, Varanasi, 221005, Uttar Pradesh, India
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