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Zhan J, Ma Y, Zhao D, Li Z, Tan H, Wang X, Liu H, Yang T. Knowledge atlas of post-traumatic epilepsy research: Based on citespace visualization analysis. Epilepsy Res 2021; 178:106790. [PMID: 34798493 DOI: 10.1016/j.eplepsyres.2021.106790] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Revised: 09/15/2021] [Accepted: 10/15/2021] [Indexed: 01/23/2023]
Abstract
The mechanism of posttraumatic epilepsy (PTE) is complicated and the treatment and prognostic effects are not satisfactory. In this study, CiteSpace and VOSviewer are used to analyze the literature related to PTE (January 2000-June 2020). The aspects of the cooperative network (author, institution, and country), keywords co-occurrence, document co-citation clustering, and journal dual-map overlay were analyzed, and the atlas was constructed. The United States, Finland, and other research institutions have frequently published PTE-related articles, thus having richer research results. The relevant research was mostly published in journals, such as Journal of Neurotrauma, Journal of Neuroscience, Brain Research, Neurobiology of Disease. Quantitative diffusion MRI plays a critical role in PTE research. The study on the susceptibility to seizures and the underlying mechanism of PTE received different degrees of attention. The present study provided an in-depth understanding of the research foundation, relevant research results, the current research frontiers, and the main research focus in the PTE field. Herein, we briefly discussed relevant key articles and also provided ideas for future research directions.
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Affiliation(s)
- Jingjing Zhan
- Key Laboratory of Evidence Science, China University of Political Science and Law, Ministry of Education, Beijing, China; Collaborative Innovation Center of Judicial Civilization, Beijing, China
| | - Yixun Ma
- Key Laboratory of Evidence Science, China University of Political Science and Law, Ministry of Education, Beijing, China; Collaborative Innovation Center of Judicial Civilization, Beijing, China
| | - Dong Zhao
- Key Laboratory of Evidence Science, China University of Political Science and Law, Ministry of Education, Beijing, China; Collaborative Innovation Center of Judicial Civilization, Beijing, China
| | - Zheng Li
- Key Laboratory of Evidence Science, China University of Political Science and Law, Ministry of Education, Beijing, China; Collaborative Innovation Center of Judicial Civilization, Beijing, China
| | - Huachao Tan
- Key Laboratory of Evidence Science, China University of Political Science and Law, Ministry of Education, Beijing, China; Collaborative Innovation Center of Judicial Civilization, Beijing, China
| | - Xu Wang
- Key Laboratory of Evidence Science, China University of Political Science and Law, Ministry of Education, Beijing, China; Collaborative Innovation Center of Judicial Civilization, Beijing, China
| | - Hongxia Liu
- China University of Political Science and Law, The Institute for Digital Technology and Law (IDTL), China; The CUPL Scientometrics and Evaluation Center of Rule of Law, China.
| | - Tiantong Yang
- Key Laboratory of Evidence Science, China University of Political Science and Law, Ministry of Education, Beijing, China; Collaborative Innovation Center of Judicial Civilization, Beijing, China.
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2
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Pathak SS, Liu D, Li T, de Zavalia N, Zhu L, Li J, Karthikeyan R, Alain T, Liu AC, Storch KF, Kaufman RJ, Jin VX, Amir S, Sonenberg N, Cao R. The eIF2α Kinase GCN2 Modulates Period and Rhythmicity of the Circadian Clock by Translational Control of Atf4. Neuron 2019; 104:724-735.e6. [PMID: 31522764 PMCID: PMC6872934 DOI: 10.1016/j.neuron.2019.08.007] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Revised: 04/13/2019] [Accepted: 08/03/2019] [Indexed: 12/20/2022]
Abstract
The integrated stress response (ISR) is activated in response to diverse stress stimuli to maintain homeostasis in neurons. Central to this process is the phosphorylation of eukaryotic translation initiation factor 2 alpha (eIF2α). Here, we report a critical role for ISR in regulating the mammalian circadian clock. The eIF2α kinase GCN2 rhythmically phosphorylates eIF2α in the suprachiasmatic circadian clock. Increased eIF2α phosphorylation shortens the circadian period in both fibroblasts and mice, whereas reduced eIF2α phosphorylation lengthens the circadian period and impairs circadian rhythmicity in animals. Mechanistically, phosphorylation of eIF2α promotes mRNA translation of Atf4. ATF4 binding motifs are identified in multiple clock genes, including Per2, Per3, Cry1, Cry2, and Clock. ATF4 binds to the TTGCAGCA motif in the Per2 promoter and activates its transcription. Together, these results demonstrate a significant role for ISR in circadian physiology and provide a potential link between dysregulated ISR and circadian dysfunction in brain diseases.
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Affiliation(s)
- Salil Saurav Pathak
- Department of Biomedical Sciences, University of Minnesota Medical School, Duluth, MN 55812, USA
| | - Dong Liu
- Department of Biomedical Sciences, University of Minnesota Medical School, Duluth, MN 55812, USA
| | - Tianbao Li
- Department of Molecular Medicine, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Nuria de Zavalia
- Center for Studies in Behavioral Neurobiology, Concordia University, Montreal, QC H4B 1R6, Canada
| | - Lei Zhu
- Douglas Mental Health University Institute and Department of Psychiatry, McGill University, Montreal, QC H4H 1R3, Canada
| | - Jin Li
- Department of Biomedical Sciences, University of Minnesota Medical School, Duluth, MN 55812, USA
| | - Ramanujam Karthikeyan
- Department of Biomedical Sciences, University of Minnesota Medical School, Duluth, MN 55812, USA
| | - Tommy Alain
- Children's Hospital of Eastern Ontario Research Institute, Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON, Canada
| | - Andrew C Liu
- Department of Physiology and Functional Genomics, University of Florida College of Medicine, Gainesville, FL 32610, USA
| | - Kai-Florian Storch
- Douglas Mental Health University Institute and Department of Psychiatry, McGill University, Montreal, QC H4H 1R3, Canada
| | - Randal J Kaufman
- Degenerative Diseases Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA 92307, USA
| | - Victor X Jin
- Department of Molecular Medicine, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Shimon Amir
- Center for Studies in Behavioral Neurobiology, Concordia University, Montreal, QC H4B 1R6, Canada.
| | - Nahum Sonenberg
- Department of Biochemistry and Goodman Cancer Research Center, McGill University, Montreal, QC H3A 1A3, Canada.
| | - Ruifeng Cao
- Department of Biomedical Sciences, University of Minnesota Medical School, Duluth, MN 55812, USA; Department of Neuroscience, University of Minnesota Medical School, Minneapolis, MN 55455, USA.
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Wang W, Zinsmaier AK, Firestone E, Lin R, Yatskievych TA, Yang S, Zhang J, Bao S. Blocking Tumor Necrosis Factor-Alpha Expression Prevents Blast-Induced Excitatory/Inhibitory Synaptic Imbalance and Parvalbumin-Positive Interneuron Loss in the Hippocampus. J Neurotrauma 2018; 35:2306-2316. [PMID: 29649942 DOI: 10.1089/neu.2018.5688] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [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 major cause of neurological disorder and death in civilian and military populations. It comprises two components-direct injury from the traumatic impact and secondary injury from ensuing neural inflammatory responses. Blocking tumor necrosis factor-alpha (TNF-α), a central regulator of neural inflammation, has been shown to improve functional recovery after TBI. However, the mechanisms underlying those therapeutic effects are still poorly understood. Here, we examined effects of 3,6'-dithiothalidomide (dTT), a potentially therapeutic TNF-α inhibitor, in mice with blast-induced TBI. We found that blast exposure resulted in elevated expression of TNF-α, activation of microglial cells, enhanced excitatory synaptic transmission, reduced inhibitory synaptic transmission, and a loss of parvalbumin-positive (PV+) inhibitory interneurons. Administration of dTT for 5 days after the blast exposure completely suppressed blast-induced increases in TNF-α transcription, largely reversed blasted-induced synaptic changes, and prevented PV+ neuron loss. However, blocking TNF-α expression by dTT failed to mitigate blast-induced microglial activation in the hippocampus, as evidenced by their non-ramified morphology. These results indicate that TNF-α plays a major role in modulating neuronal functions in blast-induced TBI and that it is a potential target for treatment of TBI-related brain disorders.
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Affiliation(s)
- Weihua Wang
- 1 Department of Physiology, College of Medicine, University of Arizona , Tucson, Arizona
| | - Alexander K Zinsmaier
- 1 Department of Physiology, College of Medicine, University of Arizona , Tucson, Arizona
| | - Ethan Firestone
- 2 Department of Otolaryngology-Head and Neck Surgery and Department of Communication Sciences and Disorders, School of Medicine, Wayne State University , Detroit, Michigan
| | - Ruizhu Lin
- 1 Department of Physiology, College of Medicine, University of Arizona , Tucson, Arizona.,3 Department of Genetics and Endocrinology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University , Guangzhou, China
| | - Tatiana A Yatskievych
- 1 Department of Physiology, College of Medicine, University of Arizona , Tucson, Arizona
| | - Sungchil Yang
- 4 Department of Biomedical Sciences, City University of Hong Kong , Kowloon, Hong Kong, China
| | - Jinsheng Zhang
- 2 Department of Otolaryngology-Head and Neck Surgery and Department of Communication Sciences and Disorders, School of Medicine, Wayne State University , Detroit, Michigan
| | - Shaowen Bao
- 1 Department of Physiology, College of Medicine, University of Arizona , Tucson, Arizona
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Neuberger EJ, Gupta A, Subramanian D, Korgaonkar AA, Santhakumar V. Converging early responses to brain injury pave the road to epileptogenesis. J Neurosci Res 2017; 97:1335-1344. [PMID: 29193309 DOI: 10.1002/jnr.24202] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Revised: 11/06/2017] [Accepted: 11/09/2017] [Indexed: 12/19/2022]
Abstract
Epilepsy, characterized by recurrent seizures and abnormal electrical activity in the brain, is one of the most prevalent brain disorders. Over two million people in the United States have been diagnosed with epilepsy and 3% of the general population will be diagnosed with it at some point in their lives. While most developmental epilepsies occur due to genetic predisposition, a class of "acquired" epilepsies results from a variety of brain insults. A leading etiological factor for epilepsy that is currently on the rise is traumatic brain injury (TBI), which accounts for up to 20% of all symptomatic epilepsies. Remarkably, the presence of an identified early insult that constitutes a risk for development of epilepsy provides a therapeutic window in which the pathological processes associated with brain injury can be manipulated to limit the subsequent development of recurrent seizure activity and epilepsy. Recent studies have revealed diverse pathologies, including enhanced excitability, activated immune signaling, cell death, and enhanced neurogenesis within a week after injury, suggesting a period of heightened adaptive and maladaptive plasticity. An integrated understanding of these processes and their cellular and molecular underpinnings could lead to novel targets to arrest epileptogenesis after trauma. This review attempts to highlight and relate the diverse early changes after trauma and their role in development of epilepsy and suggests potential strategies to limit neurological complications in the injured brain.
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Affiliation(s)
- Eric J Neuberger
- Department of Pharmacology, Physiology & Neuroscience, Rutgers New Jersey Medical School, Newark, NJ
| | - Akshay Gupta
- Department of Pharmacology, Physiology & Neuroscience, Rutgers New Jersey Medical School, Newark, NJ
| | - Deepak Subramanian
- Department of Pharmacology, Physiology & Neuroscience, Rutgers New Jersey Medical School, Newark, NJ
| | - Akshata A Korgaonkar
- Department of Pharmacology, Physiology & Neuroscience, Rutgers New Jersey Medical School, Newark, NJ
| | - Vijayalakshmi Santhakumar
- Department of Pharmacology, Physiology & Neuroscience, Rutgers New Jersey Medical School, Newark, NJ
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5
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White ER, Pinar C, Bostrom CA, Meconi A, Christie BR. Mild Traumatic Brain Injury Produces Long-Lasting Deficits in Synaptic Plasticity in the Female Juvenile Hippocampus. J Neurotrauma 2017; 34:1111-1123. [DOI: 10.1089/neu.2016.4638] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Affiliation(s)
- Emily R. White
- Division of Medical Sciences and Neuroscience Graduate Program, University of Victoria, Victoria, British Columbia, Canada
| | - Cristina Pinar
- Division of Medical Sciences and Neuroscience Graduate Program, University of Victoria, Victoria, British Columbia, Canada
| | - Crystal A. Bostrom
- Division of Medical Sciences and Neuroscience Graduate Program, University of Victoria, Victoria, British Columbia, Canada
| | - Alicia Meconi
- Division of Medical Sciences and Neuroscience Graduate Program, University of Victoria, Victoria, British Columbia, Canada
| | - Brian R. Christie
- Division of Medical Sciences and Neuroscience Graduate Program, University of Victoria, Victoria, British Columbia, Canada
- Centre for Brain Health and Program in Neuroscience, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, British Columbia, Canada
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6
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Abstract
Posttraumatic epilepsy (PTE) is one of the most common and devastating complications of traumatic brain injury (TBI). Currently, the etiopathology and mechanisms of PTE are poorly understood and as a result, there is no effective treatment or means to prevent it. Antiepileptic drugs remain common preventive strategies in the management of TBI to control acute posttraumatic seizures and to prevent the development of PTE, although their efficacy in the latter case is disputed. Different strategies of PTE prophylaxis have been showing promise in preclinical models, but their translation to the clinic still remains elusive due in part to the variability of these models and the fact they do not recapitulate all complex pathologies associated with human TBI. TBI is a multifaceted disorder reflected in several potentially epileptogenic alterations in the brain, including mechanical neuronal and vascular damage, parenchymal and subarachnoid hemorrhage, subsequent toxicity caused by iron-rich hemoglobin breakdown products, and energy disruption resulting in secondary injuries, including excitotoxicity, gliosis, and neuroinflammation, often coexisting to a different degree. Several in vivo models have been developed to reproduce the acute TBI cascade of events, to reflect its anatomical pathologies, and to replicate neurological deficits. Although acute and chronic recurrent posttraumatic seizures are well-recognized phenomena in these models, there is only a limited number of studies focused on PTE. The most used mechanical TBI models with documented electroencephalographic and behavioral seizures with remote epileptogenesis include fluid percussion, controlled cortical impact, and weight-drop. This chapter describes the most popular models of PTE-induced TBI models, focusing on the controlled cortical impact and the fluid percussion injury models, the methods of behavioral and electroencephalogram seizure assessments, and other approaches to detect epileptogenic properties, and discusses their potential application for translational research.
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Cao L, Bie X, Huo S, Du J, Liu L, Song W. Effects of diazepam on glutamatergic synaptic transmission in the hippocampal CA1 area of rats with traumatic brain injury. Neural Regen Res 2015; 9:1897-901. [PMID: 25558239 PMCID: PMC4281428 DOI: 10.4103/1673-5374.145357] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/01/2014] [Indexed: 01/20/2023] Open
Abstract
The activity of the Schaffer collaterals of hippocampal CA3 neurons and hippocampal CA1 neurons has been shown to increase after fluid percussion injury. Diazepam can inhibit the hyperexcitability of rat hippocampal neurons after injury, but the mechanism by which it affects excitatory synaptic transmission remains poorly understood. Our results showed that diazepam treatment significantly increased the slope of input-output curves in rat neurons after fluid percussion injury. Diazepam significantly decreased the numbers of spikes evoked by super stimuli in the presence of 15 μmol/L bicuculline, indicating the existence of inhibitory pathways in the injured rat hippocampus. Diazepam effectively increased the paired-pulse facilitation ratio in the hippocampal CA1 region following fluid percussion injury, reduced miniature excitatory postsynaptic potentials, decreased action-potential-dependent glutamine release, and reversed spontaneous glutamine release. These data suggest that diazepam could decrease the fluid percussion injury-induced enhancement of excitatory synaptic transmission in the rat hippocampal CA1 area.
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Affiliation(s)
- Lei Cao
- Department of Functional Neurosurgery, Xi'an Red Cross Hospital, Xi'an, Shaanxi Province, China ; Department of Rehabilitation Medicine, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Xiaohua Bie
- Department of Functional Neurosurgery, Xi'an Red Cross Hospital, Xi'an, Shaanxi Province, China
| | - Su Huo
- Department of Rehabilitation Medicine, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Jubao Du
- Department of Rehabilitation Medicine, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Lin Liu
- Department of Rehabilitation Medicine, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Weiqun Song
- Department of Rehabilitation Medicine, Xuanwu Hospital, Capital Medical University, Beijing, China
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8
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Schmitt S, Dichter MA. Electrophysiologic recordings in traumatic brain injury. HANDBOOK OF CLINICAL NEUROLOGY 2015; 127:319-339. [PMID: 25702226 DOI: 10.1016/b978-0-444-52892-6.00021-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Following a traumatic brain injury (TBI), the brain undergoes numerous electrophysiologic changes. The most common techniques used to evaluate these changes include electroencepalography (EEG) and evoked potentials. In animals, EEGs immediately following TBI can show either diffuse slowing or voltage attenuation, or high voltage spiking. Following a TBI, many animals display evidence of hippocampal excitability and a reduced seizure threshold. Some mice subjected to severe TBI via a fluid percussion injury will eventually develop seizures, which provides a useful potential model for studying the neurophysiology of epileptogenesis. In humans, the EEG changes associated with mild TBI are relatively subtle and may be challenging to distinguish from EEG changes seen in other conditions. Quantitative EEG (QEEG) may enhance the ability to detect post-traumatic electrophysiologic changes following a mild TBI. Some types of evoked potential (EP) and event related potential (ERP) can also be used to detect post-traumatic changes following a mild TBI. Continuous EEG monitoring (cEEG) following moderate and severe TBI is useful in detecting the presence of seizures and status epilepticus acutely following an injury, although some seizures may only be detectable using intracranial monitoring. CEEG can also be helpful for assessing prognosis after moderate or severe TBI. EPs, particularly somatosensory evoked potentials, can also be useful in assessing prognosis following severe TBI. The role for newer technologies such as magnetoencephalography and bispectral analysis (BIS) in the evaluation of patients with TBI remains unclear.
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Affiliation(s)
- Sarah Schmitt
- Department of Neurology, University of Pennsylvania, Philadelphia, PA, USA
| | - Marc A Dichter
- Department of Neurology, University of Pennsylvania, Philadelphia, PA, USA.
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9
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Zhang J, Carnduff L, Norman G, Josey T, Wang Y, Sawyer TW, Martyniuk CJ, Langlois VS. Transcriptional profiling in rat hair follicles following simulated Blast insult: a new diagnostic tool for traumatic brain injury. PLoS One 2014; 9:e104518. [PMID: 25136963 PMCID: PMC4138085 DOI: 10.1371/journal.pone.0104518] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2014] [Accepted: 07/11/2014] [Indexed: 01/05/2023] Open
Abstract
With wide adoption of explosive-dependent weaponry during military activities, Blast-induced neurotrauma (BINT)-induced traumatic brain injury (TBI) has become a significant medical issue. Therefore, a robust and accessible biomarker system is in demand for effective and efficient TBI diagnosis. Such systems will also be beneficial to studies of TBI pathology. Here we propose the mammalian hair follicles as a potential candidate. An Advanced Blast Simulator (ABS) was developed to generate shock waves simulating traumatic conditions on brains of rat model. Microarray analysis was performed in hair follicles to identify the gene expression profiles that are associated with shock waves. Gene set enrichment analysis (GSEA) and sub-network enrichment analysis (SNEA) were used to identify cell processes and molecular signaling cascades affected by simulated bomb blasts. Enrichment analyses indicated that genes with altered expression levels were involved in central nervous system (CNS)/peripheral nervous system (PNS) responses as well as signal transduction including Ca2+, K+-transportation-dependent signaling, Toll-Like Receptor (TLR) signaling and Mitogen Activated Protein Kinase (MAPK) signaling cascades. Many of the pathways identified as affected by shock waves in the hair follicles have been previously reported to be TBI responsive in other organs such as brain and blood. The results suggest that the hair follicle has some common TBI responsive molecular signatures to other tissues. Moreover, various TBI-associated diseases were identified as preferentially affected using a gene network approach, indicating that the hair follicle may be capable of reflecting comprehensive responses to TBI conditions. Accordingly, the present study demonstrates that the hair follicle is a potentially viable system for rapid and non-invasive TBI diagnosis.
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Affiliation(s)
- Jing Zhang
- Chemistry and Chemical Engineering Department, Royal Military College of Canada, Kingston, Ontario, Canada
| | - Lisa Carnduff
- Chemistry and Chemical Engineering Department, Royal Military College of Canada, Kingston, Ontario, Canada
| | - Grant Norman
- Chemistry and Chemical Engineering Department, Royal Military College of Canada, Kingston, Ontario, Canada
| | - Tyson Josey
- Defence Research and Development Canada – Suffield, Medicine Hat, Alberta, Canada
| | - Yushan Wang
- Defence Research and Development Canada – Suffield, Medicine Hat, Alberta, Canada
| | - Thomas W. Sawyer
- Defence Research and Development Canada – Suffield, Medicine Hat, Alberta, Canada
| | | | - Valerie S. Langlois
- Chemistry and Chemical Engineering Department, Royal Military College of Canada, Kingston, Ontario, Canada
- * E-mail:
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Warren KM, Reeves TM, Phillips LL. MT5-MMP, ADAM-10, and N-cadherin act in concert to facilitate synapse reorganization after traumatic brain injury. J Neurotrauma 2012; 29:1922-40. [PMID: 22489706 DOI: 10.1089/neu.2012.2383] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Matrix metalloproteinases (MMPs) influence synaptic recovery following traumatic brain injury (TBI). Membrane type 5-matrix metalloproteinase (MT5-MMP) and a distintegrin and metalloproteinase-10 (ADAM-10) are membrane-bound MMPs that cleave N-cadherin, a protein critical to synapse stabilization. This study examined protein and mRNA expression of MT5-MMP, ADAM-10, and N-cadherin after TBI, contrasting adaptive and maladaptive synaptogenesis. The effect of MMP inhibition on MT5-MMP, ADAM-10, and N-cadherin was assessed during maladaptive plasticity and correlated with synaptic function. Rats were subjected to adaptive unilateral entorhinal cortical lesion (UEC) or maladaptive fluid percussion TBI+bilateral entorhinal cortical lesion (TBI+BEC). Hippocampal MT5-MMP and ADAM-10 protein was significantly elevated 2 and 7 days post-injury. At 15 days after UEC, each MMP returned to control level, while TBI+BEC ADAM-10 remained elevated. At 2 and 7 days, N-cadherin protein was below control. By the 15-day synapse stabilization phase, UEC N-cadherin rose above control, a shift not seen for TBI+BEC. At 7 days, increased TBI+BEC ADAM-10 transcript correlated with protein elevation. UEC ADAM-10 mRNA did not change, and no differences in MT5-MMP or N-cadherin mRNA were detected. Confocal imaging showed MT5-MMP, ADAM-10, and N-cadherin localization within reactive astrocytes. MMP inhibition attenuated ADAM-10 protein 15 days after TBI+BEC and increased N-cadherin. This inhibition partially restored long-term potentiation induction, but did not affect paired-pulse facilitation. Our results confirm time- and injury-dependent expression of MT5-MMP, ADAM-10, and N-cadherin during reactive synaptogenesis. Persistent ADAM-10 expression was correlated with attenuated N-cadherin level and reduced functional recovery. MMP inhibition shifted ADAM-10 and N-cadherin toward adaptive expression and improved synaptic function.
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Affiliation(s)
- Kelly M Warren
- Department of Anatomy and Neurobiology, School of Medicine, Virginia Commonwealth University Medical Center, Richmond, VA 23298, USA
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11
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Yamashita S, Hasuo H, Tokutomi T, Shigemori M, Akasu T. Edaravone attenuates impairment of synaptic plasticity in granule cell layer of the dentate gyrus following traumatic brain injury. Kurume Med J 2011; 58:47-58. [PMID: 22251821 DOI: 10.2739/kurumemedj.58.47] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Effects of edaravone, a free radical scavenger, on post-traumatic impairment of long-term potentiation (LTP) were examined in granule cell layers of the dentate gyrus (DG) in vitro. Field EPSPs (fEPSPs) evoked by stimulation of the perforant path (PP) were recorded extracellularly in the DG one week after a moderate impact applied by a fluid percussion injury (FPI) device. High frequency stimulation (HFS) of the PP caused LTP of the fEPSP-slope in slices from naïve and sham-operated rats, however, the LTP was strongly depressed in slices from FPI rats. Intraperitoneal administration of edaravone 15 min after FPI prevented the hyperactivities of DG neurons and attenuated impairment of the LTP in FPI rat dentate granular cells. In vitro application of spermine NONOate (sp-NO), a nitric oxide (NO) donor, for 30 min produced a gradual increase in the fEPSP-slope, lasting for more than 2 h. Edaravone attenuated the enhancement of the fEPSP-slope induced by sp-NO. After sp-NO treatment HFS could not produce an obvious LTP in the DG granule cell layer. Pretreatment of DG slices with edaravone prevented the sp-NO-induced impairment of LTP. These results suggest that administration of edaravone after FPI protects against post-traumatic impairment of LTP in granule cell layers of the DG, possibly by scavenging NO-related radicals.
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Affiliation(s)
- Shin Yamashita
- Department of Physiology, Kurume University School of Medicine, Kurume University, Kurume 830-0011, Japan
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12
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Yu Z, Morrison B. Experimental mild traumatic brain injury induces functional alteration of the developing hippocampus. J Neurophysiol 2009; 103:499-510. [PMID: 19923245 DOI: 10.1152/jn.00775.2009] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
It is estimated that approximately 1.5 million Americans suffer a traumatic brain injury (TBI) every year, of which approximately 80% are considered mild injuries. Because symptoms caused by mild TBI last less than half an hour by definition and apparently resolve without treatment, the study of mild TBI is often neglected resulting in a significant knowledge gap for this wide-spread problem. In this work, we studied functional (electrophysiological) alterations of the neonatal/juvenile hippocampus after experimental mild TBI. Our previous work reported significant cell death after in vitro injury >10% biaxial deformation. Here we report that biaxial deformation as low as 5% affected neuronal function during the first week after in vitro mild injury of hippocampal slice cultures. These results suggest that even very mild mechanical events may lead to a quantifiable neuronal network dysfunction. Furthermore, our results highlight that safe limits of mechanical deformation or tolerance criteria may be specific to a particular outcome measure and that neuronal function is a more sensitive measure of injury than cell death. In addition, the age of the tissue at injury was found to be an important factor affecting posttraumatic deficits in electrophysiological function, indicating a relationship between developmental status and vulnerability to mild injury. Our findings suggest that mild pediatric TBI could result in functional deficits that are more serious than currently appreciated.
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Affiliation(s)
- Zhe Yu
- Department of Biomedical Engineering, Columbia University, 1210 Amsterdam Ave., 351 Engineering Terrace, New York, NY 10027, USA
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Ooba S, Hasuo H, Shigemori M, Yamashita S, Akasu T. Mild hypothermia prevents post-traumatic hyperactivity of excitatory synapses in rat hippocampal CA1 pyramidal neurons. Kurume Med J 2009; 56:49-59. [PMID: 20505282 DOI: 10.2739/kurumemedj.56.49] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
The present experiment examined the effect of mild hypothermia (35 degrees C) on the post-traumatic hyperactivity of rat hippocampal CA1 neurons in horizontal brain slices. One week after fluid percussion injury (FPI), the optical response evoked by stimulation of the Schaffer collaterals increased in amplitude and propagation area in hippocampal CA1 slices. FPI did not alter the fast optical response that reflected the action potential of the Schaffer collaterals but enhanced the slow component that reflected the excitatory postsynaptic response. FPI increased the slope of the input-output relation (I/O function), suggesting that FPI increases the efficacy of excitatory synaptic transmission in the hippocampal CA1 pyramidal neurons. To examine the effect of low temperature on post-traumatic hyperactivity of hippocampal CA1 neurons, mild hypothermia (35 degrees C) was administered to rats 15 min after FPI and maintained for 1-3 h. One week after FPI, the activity of hippocampal CA1 neurons in rats with mild hypothermia appeared to be reduced as compared with those receiving FPI alone. The post-traumatic enhancement of the I/O function of the slow optical response was prevented by mild hypothermia. These results suggest that mild hypothermia applied 15 min after FPI attenuates the post-traumatic hyperactivity of excitatory synapses in rat hippocampal CA1 neurons.
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Affiliation(s)
- Satomi Ooba
- Department of Physiology, Kurume University School of Medicine, Kurume, Japan
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Ooba S, Hasuo H, Shigemori M, Akasu T. Diazepam attenuates the post-traumatic hyperactivity of excitatory synapses in rat hippocampal CA1 neurons. Neurosci Res 2008; 62:195-205. [PMID: 18793683 DOI: 10.1016/j.neures.2008.08.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2007] [Revised: 07/04/2008] [Accepted: 08/13/2008] [Indexed: 11/20/2022]
Abstract
The effect of diazepam, a benzodiazepine derivative, on the post-traumatic hyperactivity of excitatory synaptic transmission was examined in rat hippocampal CA1 area. Optical recordings showed that the activity of hippocampal neurons was enhanced in rats treated with fluid percussion injury (FPI) as compared with that of sham-operated rats. The optical response was characterized by fast and slow components. FPI did not affect the fast component that reflects presynaptic action potentials, but enhanced the slow component that reflects excitatory synaptic responses. Intracellular recordings showed that the amplitude and duration of the excitatory postsynaptic potential (EPSP) were increased after FPI. However, FPI did not affect the resting membrane potential and action potentials of hippocampal neurons. Intraperitoneal (i.p.) administration of diazepam (30 and 90 min after FPI) attenuated the post-traumatic hyperactivity of the slow optical response. The slope of input-to-output relation of excitatory synapses was decreased by acute administration of diazepam to FPI rats, but not by delayed administration of diazepam (4 and 5 h after FPI). The fast optical responses were not affected by either FPI or i.p. administration of diazepam. These results suggest that administration of diazepam at early post-traumatic period prevents the FPI-induced delayed enhancement of excitatory synaptic transmission in rat hippocampal CA1 neurons.
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Affiliation(s)
- S Ooba
- Department of Physiology, Kurume University School of Medicine, Kurume 830-0011, Japan
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Yaka R, Biegon A, Grigoriadis N, Simeonidou C, Grigoriadis S, Alexandrovich AG, Matzner H, Schumann J, Trembovler V, Tsenter J, Shohami E. D‐cycloserine improves functional recovery and reinstates long‐term potentiation (LTP) in a mouse model of closed head injury. FASEB J 2007; 21:2033-41. [PMID: 17351125 DOI: 10.1096/fj.06-7856com] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Traumatic brain injury triggers a massive glutamate efflux, activation of NMDA receptor channels, and cell death. Recently, we reported that NMDA receptors in mice are down-regulated from hours to days following closed head injury (CHI), and treatment with NMDA improved recovery of motor and cognitive functions up to 14 d post-injury. Here we show that a single injection of a low dose of D-cycloserine (DCS), a partial NMDA receptor agonist, in CHI mice 24 h post-injury, resulted in a faster and greater recovery of motor and memory functions as assessed by neurological severity score and object recognition tests, respectively. Moreover, DCS treatment of CHI mice led to a significant improvement of hippocampal long-term potentiation (LTP) in the CA1 region that was completely blunted in CHI control mice. However, DCS did not improve CHI-induced impairment in synaptic glutamate release measured by paired pulse facilitation (PPF) ratio in hippocampal CA1 region. Finally, CHI-induced reduction of brain-derived neurotrophic factor (BDNF) was fully restored following DCS treatment. Since DCS is in clinical use for other indications, the present study offers a novel approach to treat human brain injury.
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Affiliation(s)
- Rami Yaka
- Department of Pharmacology, School of Pharmacy, The Hebrew University of Jerusalem, POB 12065, Jerusalem 91120, Israel.
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