1
|
Krieg JL, Leonard AV, Turner RJ, Corrigan F. Identifying the Phenotypes of Diffuse Axonal Injury Following Traumatic Brain Injury. Brain Sci 2023; 13:1607. [PMID: 38002566 PMCID: PMC10670443 DOI: 10.3390/brainsci13111607] [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: 11/01/2023] [Revised: 11/15/2023] [Accepted: 11/17/2023] [Indexed: 11/26/2023] Open
Abstract
Diffuse axonal injury (DAI) is a significant feature of traumatic brain injury (TBI) across all injury severities and is driven by the primary mechanical insult and secondary biochemical injury phases. Axons comprise an outer cell membrane, the axolemma which is anchored to the cytoskeletal network with spectrin tetramers and actin rings. Neurofilaments act as space-filling structural polymers that surround the central core of microtubules, which facilitate axonal transport. TBI has differential effects on these cytoskeletal components, with axons in the same white matter tract showing a range of different cytoskeletal and axolemma alterations with different patterns of temporal evolution. These require different antibodies for detection in post-mortem tissue. Here, a comprehensive discussion of the evolution of axonal injury within different cytoskeletal elements is provided, alongside the most appropriate methods of detection and their temporal profiles. Accumulation of amyloid precursor protein (APP) as a result of disruption of axonal transport due to microtubule failure remains the most sensitive marker of axonal injury, both acutely and chronically. However, a subset of injured axons demonstrate different pathology, which cannot be detected via APP immunoreactivity, including degradation of spectrin and alterations in neurofilaments. Furthermore, recent work has highlighted the node of Ranvier and the axon initial segment as particularly vulnerable sites to axonal injury, with loss of sodium channels persisting beyond the acute phase post-injury in axons without APP pathology. Given the heterogenous response of axons to TBI, further characterization is required in the chronic phase to understand how axonal injury evolves temporally, which may help inform pharmacological interventions.
Collapse
Affiliation(s)
- Justin L Krieg
- Translational Neuropathology Laboratory, School of Biomedicine, Faculty of Health and Medical Sciences, The University of Adelaide, Adelaide 5000, Australia
| | - Anna V Leonard
- Translational Neuropathology Laboratory, School of Biomedicine, Faculty of Health and Medical Sciences, The University of Adelaide, Adelaide 5000, Australia
| | - Renée J Turner
- Translational Neuropathology Laboratory, School of Biomedicine, Faculty of Health and Medical Sciences, The University of Adelaide, Adelaide 5000, Australia
| | - Frances Corrigan
- Translational Neuropathology Laboratory, School of Biomedicine, Faculty of Health and Medical Sciences, The University of Adelaide, Adelaide 5000, Australia
| |
Collapse
|
2
|
Rashno M, Sarkaki A, Farbood Y, Rashno M, Khorsandi L, Naseri MKG, Dianat M. Possible mechanisms involved in the neuroprotective effects of chrysin against mild traumatic brain injury-induced spatial cognitive decline: An in vivo study in a rat model. Brain Res Bull 2023; 204:110779. [PMID: 37827266 DOI: 10.1016/j.brainresbull.2023.110779] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Revised: 10/04/2023] [Accepted: 10/09/2023] [Indexed: 10/14/2023]
Abstract
Traumatic brain injury (TBI) is recognized as an important risk factor for cognitive deficits. The present study was designed to determine the potential neuroprotective effects of chrysin, a natural flavonoid compound, against TBI-induced spatial cognitive decline and the possible mechanisms involved. Oral administration of chrysin (25, 50, or 100 mg/kg/day) was initiated in rats immediately following the induction of the diffuse TBI model using the weight-dropping Marmarou model. Spatial cognitive ability, hippocampal synaptic plasticity, blood-brain barrier (BBB) permeability, brain water content, and histological changes were assessed at scheduled time points. The animals subjected to TBI exhibited spatial cognitive decline in the Morris water maze (MWM) test, which was accompanied by inhibition of hippocampal long-term potentiation (LTP) induction at the perforant path-dentate gyrus (PP-DG) synapses. Additionally, TBI caused BBB disruption, brain edema, and neuronal loss. Interestingly, treatment with chrysin (especially in the dose of 100 mg/kg) alleviated all the above-mentioned neuropathological changes related to TBI. The results provide evidence that chrysin improves TBI-induced spatial cognitive decline, which may be partly related to the amelioration of hippocampal synaptic dysfunction, alleviation of BBB disruption, reduction of brain edema, and prevention of neuronal loss.
Collapse
Affiliation(s)
- Masome Rashno
- Department of Physiology, School of Medicine, Persian Gulf Physiology Research Center, Medical Basic Sciences Research Institute, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| | - Alireza Sarkaki
- Department of Physiology, School of Medicine, Persian Gulf Physiology Research Center, Medical Basic Sciences Research Institute, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
| | - Yaghoob Farbood
- Department of Physiology, School of Medicine, Persian Gulf Physiology Research Center, Medical Basic Sciences Research Institute, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| | - Mohammad Rashno
- Department of Immunology, Faculty of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran; Cellular and Molecular Research Center, Medical Basic Sciences Research Institute, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| | - Layasadat Khorsandi
- Cellular and Molecular Research Center, Medical Basic Sciences Research Institute, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| | - Mohammad Kazem Gharib Naseri
- Department of Physiology, School of Medicine, Persian Gulf Physiology Research Center, Medical Basic Sciences Research Institute, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| | - Mahin Dianat
- Department of Physiology, School of Medicine, Persian Gulf Physiology Research Center, Medical Basic Sciences Research Institute, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| |
Collapse
|
3
|
Tian Z, Lu XT, Jiang X, Tian J. Bryostatin-1: a promising compound for neurological disorders. Front Pharmacol 2023; 14:1187411. [PMID: 37351510 PMCID: PMC10282138 DOI: 10.3389/fphar.2023.1187411] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Accepted: 05/23/2023] [Indexed: 06/24/2023] Open
Abstract
The central nervous system (CNS) is the most complex system in human body, and there is often a lack of effective treatment strategies for the disorders related with CNS. Natural compounds with multiple pharmacological activities may offer better options because they have broad cellular targets and potentially produce synergic and integrative effects. Bryostatin-1 is one of such promising compounds, a macrolide separated from marine invertebrates. Bryostatin-1 has been shown to produce various biological activities through binding with protein kinase C (PKC). In this review, we mainly summarize the pharmacological effects of bryostatin-1 in the treatment of multiple neurological diseases in preclinical studies and clinical trials. Bryostatin-1 is shown to have great therapeutic potential for Alzheimer's disease, multiple sclerosis, fragile X syndrome, stroke, traumatic brain injury, and depression. It exhibits significant rescuing effects on the deficits of spatial learning, cognitive function, memory and other neurological functions caused by diseases, producing good neuroprotective effects. The promising neuropharmacological activities of bryostatin-1 suggest that it is a potential candidate for the treatment of related neurological disorders although there are still some issues needed to be addressed before its application in clinic.
Collapse
Affiliation(s)
- Zhen Tian
- College of Pharmaceutical Sciences, Southwest University, Chongqing, China
| | - Xin-Tong Lu
- College of Pharmaceutical Sciences, Southwest University, Chongqing, China
| | - Xun Jiang
- Department of Pediatrics, Tangdu Hospital of Fourth Military Medical University, Xi’an, China
| | - Jiao Tian
- Department of Infection, Children’s Hospital of Chongqing Medical University, National Clinical Research Center for Child Health and Disorders, Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing Key Laboratory of Child Infection and Immunity, The First Batch of Key Disciplines on Public Health in Chongqing, Chongqing, China
| |
Collapse
|
4
|
Adegoke MA, Teter O, Meaney DF. Flexibility of in vitro cortical circuits influences resilience from microtrauma. Front Cell Neurosci 2022; 16:991740. [PMID: 36589287 PMCID: PMC9803265 DOI: 10.3389/fncel.2022.991740] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Accepted: 11/28/2022] [Indexed: 12/23/2022] Open
Abstract
Background Small clusters comprising hundreds to thousands of neurons are an important level of brain architecture that correlates single neuronal properties to fulfill brain function, but the specific mechanisms through which this scaling occurs are not well understood. In this study, we developed an in vitro experimental platform of small neuronal circuits (islands) to probe the importance of structural properties for their development, physiology, and response to microtrauma. Methods Primary cortical neurons were plated on a substrate patterned to promote attachment in clusters of hundreds of cells (islands), transduced with GCaMP6f, allowed to mature until 10-13 days in vitro (DIV), and monitored with Ca2+ as a non-invasive proxy for electrical activity. We adjusted two structural factors-island size and cellular density-to evaluate their role in guiding spontaneous activity and network formation in neuronal islands. Results We found cellular density, but not island size, regulates of circuit activity and network function in this system. Low cellular density islands can achieve many states of activity, while high cellular density biases islands towards a limited regime characterized by low rates of activity and high synchronization, a property we summarized as "flexibility." The injury severity required for an island to lose activity in 50% of its population was significantly higher in low-density, high flexibility islands. Conclusion Together, these studies demonstrate flexible living cortical circuits are more resilient to microtrauma, providing the first evidence that initial circuit state may be a key factor to consider when evaluating the consequences of trauma to the cortex.
Collapse
Affiliation(s)
- Modupe A. Adegoke
- Department of Bioengineering, School of Engineering and Applied Sciences, University of Pennsylvania, Philadelphia, PA, United States
| | - Olivia Teter
- Department of Bioengineering, School of Engineering and Applied Sciences, University of Pennsylvania, Philadelphia, PA, United States
| | - David F. Meaney
- Department of Bioengineering, School of Engineering and Applied Sciences, University of Pennsylvania, Philadelphia, PA, United States,Department of Neurosurgery, Penn Center for Brain Injury and Repair, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States,*Correspondence: David F. Meaney,
| |
Collapse
|
5
|
Seillier C, Lesept F, Toutirais O, Potzeha F, Blanc M, Vivien D. Targeting NMDA Receptors at the Neurovascular Unit: Past and Future Treatments for Central Nervous System Diseases. Int J Mol Sci 2022; 23:ijms231810336. [PMID: 36142247 PMCID: PMC9499580 DOI: 10.3390/ijms231810336] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Revised: 08/30/2022] [Accepted: 09/02/2022] [Indexed: 11/16/2022] Open
Abstract
The excitatory neurotransmission of the central nervous system (CNS) mainly involves glutamate and its receptors, especially N-methyl-D-Aspartate receptors (NMDARs). These receptors have been extensively described on neurons and, more recently, also on other cell types. Nowadays, the study of their differential expression and function is taking a growing place in preclinical and clinical research. The diversity of NMDAR subtypes and their signaling pathways give rise to pleiotropic functions such as brain development, neuronal plasticity, maturation along with excitotoxicity, blood-brain barrier integrity, and inflammation. NMDARs have thus emerged as key targets for the treatment of neurological disorders. By their large extracellular regions and complex intracellular structures, NMDARs are modulated by a variety of endogenous and pharmacological compounds. Here, we will present an overview of NMDAR functions on neurons and other important cell types involved in the pathophysiology of neurodegenerative, neurovascular, mental, autoimmune, and neurodevelopmental diseases. We will then discuss past and future development of NMDAR targeting drugs, including innovative and promising new approaches.
Collapse
Affiliation(s)
- Célia Seillier
- Normandie University, UNICAEN, INSERM, GIP Cyceron, Institute Blood and Brain @Caen-Normandie (BB@C), UMR-S U1237, Physiopathology and Imaging of Neurological Disorders (PhIND), 14000 Caen, France
| | - Flavie Lesept
- Lys Therapeutics, Cyceron, Boulevard Henri Becquerel, 14000 Caen, France
| | - Olivier Toutirais
- Normandie University, UNICAEN, INSERM, GIP Cyceron, Institute Blood and Brain @Caen-Normandie (BB@C), UMR-S U1237, Physiopathology and Imaging of Neurological Disorders (PhIND), 14000 Caen, France
- Department of Immunology and Histocompatibility (HLA), Caen University Hospital, CHU, 14000 Caen, France
| | - Fanny Potzeha
- Lys Therapeutics, Cyceron, Boulevard Henri Becquerel, 14000 Caen, France
| | - Manuel Blanc
- Lys Therapeutics, Cyceron, Boulevard Henri Becquerel, 14000 Caen, France
| | - Denis Vivien
- Normandie University, UNICAEN, INSERM, GIP Cyceron, Institute Blood and Brain @Caen-Normandie (BB@C), UMR-S U1237, Physiopathology and Imaging of Neurological Disorders (PhIND), 14000 Caen, France
- Department of Clinical Research, Caen University Hospital, CHU, 14000 Caen, France
- Correspondence:
| |
Collapse
|
6
|
Lantoine J, Procès A, Villers A, Halliez S, Buée L, Ris L, Gabriele S. Inflammatory Molecules Released by Mechanically Injured Astrocytes Trigger Presynaptic Loss in Cortical Neuronal Networks. ACS Chem Neurosci 2021; 12:3885-3897. [PMID: 34614352 DOI: 10.1021/acschemneuro.1c00488] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Deformation, compression, or stretching of brain tissues cause diffuse axonal injury (DAI) and induce structural and functional alterations of astrocytes, the most abundant cell type in the brain. To gain further insight into the role of mechanically activated astrocytes on neuronal networks, this study was designed to investigate whether cytokines released by mechanically activated astrocytes can affect the growth and synaptic connections of cortical neuronal networks. Astrocytes were cultivated on elastic membranes and subjected to repetitive mechanical insults, whereas well-defined protein micropatterns were used to form standardized neuronal networks. GFAP staining showed that astrocytes were mechanically activated after two cycles of stretch and mesoscale discovery assays indicated that injured astrocytes released four major cytokines. To understand the role of these cytokines, neuronal networks were cultured with the supernatant of healthy or mechanically activated astrocytes, and the individual contribution of the proinflammatory cytokine tumor necrosis factor-α (TNF-α) was studied. We found that the supernatant of two-cycle stretched astrocytes decreased presynaptic terminals and indicated that TNF-α must be considered a key player of the synaptic loss. Furthermore, our results indicate that cytokines released by injured astrocytes significantly modulate the balance between TNFR1 and TNFR2 receptors by enhancing R2 receptors. We demonstrated that TNF-α is not involved in this process, suggesting a predominant role of other secreted cytokines. Together, these results contribute to a better understanding of the consequences of repetitive astrocyte deformations and highlight the role of inflammatory signaling pathways in synaptic plasticity and modulation of TNFR1 and TNFR2 receptors.
Collapse
Affiliation(s)
- Joséphine Lantoine
- Mechanobiology & Soft Matter Group, Interfaces and Complex Fluids Laboratory, Research Institute for Biosciences, University of Mons, 7000 Mons, Belgium
| | - Anthony Procès
- Mechanobiology & Soft Matter Group, Interfaces and Complex Fluids Laboratory, Research Institute for Biosciences, University of Mons, 7000 Mons, Belgium
- Laboratory of Neuroscience, Research Institute for Biosciences, Faculty of Medicine and Pharmacy, University of Mons, 7000 Mons, Belgium
| | - Agnès Villers
- Laboratory of Neuroscience, Research Institute for Biosciences, Faculty of Medicine and Pharmacy, University of Mons, 7000 Mons, Belgium
| | - Sophie Halliez
- Univ. Lille, Inserm, CHU Lille, U1172 - LilNCog - Lille Neuroscience & Cognition, LabEx DISTALZ, F-59000 Lille, France
| | - Luc Buée
- Univ. Lille, Inserm, CHU Lille, U1172 - LilNCog - Lille Neuroscience & Cognition, LabEx DISTALZ, F-59000 Lille, France
| | - Laurence Ris
- Laboratory of Neuroscience, Research Institute for Biosciences, Faculty of Medicine and Pharmacy, University of Mons, 7000 Mons, Belgium
| | - Sylvain Gabriele
- Mechanobiology & Soft Matter Group, Interfaces and Complex Fluids Laboratory, Research Institute for Biosciences, University of Mons, 7000 Mons, Belgium
| |
Collapse
|
7
|
Jerusalem A, Al-Rekabi Z, Chen H, Ercole A, Malboubi M, Tamayo-Elizalde M, Verhagen L, Contera S. Electrophysiological-mechanical coupling in the neuronal membrane and its role in ultrasound neuromodulation and general anaesthesia. Acta Biomater 2019; 97:116-140. [PMID: 31357005 DOI: 10.1016/j.actbio.2019.07.041] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Revised: 07/20/2019] [Accepted: 07/23/2019] [Indexed: 01/23/2023]
Abstract
The current understanding of the role of the cell membrane is in a state of flux. Recent experiments show that conventional models, considering only electrophysiological properties of a passive membrane, are incomplete. The neuronal membrane is an active structure with mechanical properties that modulate electrophysiology. Protein transport, lipid bilayer phase, membrane pressure and stiffness can all influence membrane capacitance and action potential propagation. A mounting body of evidence indicates that neuronal mechanics and electrophysiology are coupled, and together shape the membrane potential in tight coordination with other physical properties. In this review, we summarise recent updates concerning electrophysiological-mechanical coupling in neuronal function. In particular, we aim at making the link with two relevant yet often disconnected fields with strong clinical potential: the use of mechanical vibrations-ultrasound-to alter the electrophysiogical state of neurons, e.g., in neuromodulation, and the theories attempting to explain the action of general anaesthetics. STATEMENT OF SIGNIFICANCE: General anaesthetics revolutionised medical practice; now an apparently unrelated technique, ultrasound neuromodulation-aimed at controlling neuronal activity by means of ultrasound-is poised to achieve a similar level of impact. While both technologies are known to alter the electrophysiology of neurons, the way they achieve it is still largely unknown. In this review, we argue that in order to explain their mechanisms/effects, the neuronal membrane must be considered as a coupled mechano-electrophysiological system that consists of multiple physical processes occurring concurrently and collaboratively, as opposed to sequentially and independently. In this framework the behaviour of the cell membrane is not the result of stereotypical mechanisms in isolation but instead emerges from the integrative behaviour of a complexly coupled multiphysics system.
Collapse
Affiliation(s)
- Antoine Jerusalem
- Department of Engineering Science, University of Oxford, Parks Road, Oxford OX1 3PJ, UK.
| | - Zeinab Al-Rekabi
- Department of Physics, University of Oxford, Parks Road, Oxford OX1 3PU, UK
| | - Haoyu Chen
- Department of Engineering Science, University of Oxford, Parks Road, Oxford OX1 3PJ, UK
| | - Ari Ercole
- Division of Anaesthesia, University of Cambridge, Addenbrooke's Hospital, Hills Road, Cambridge CB2 0QQ, UK
| | - Majid Malboubi
- Department of Engineering Science, University of Oxford, Parks Road, Oxford OX1 3PJ, UK
| | - Miren Tamayo-Elizalde
- Department of Engineering Science, University of Oxford, Parks Road, Oxford OX1 3PJ, UK
| | - Lennart Verhagen
- Wellcome Centre for Integrative Neuroimaging (WIN), Department of Experimental Psychology, University of Oxford, Oxford OX1 3TA, UK; WIN, Centre for Functional MRI of the Brain, Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, University of Oxford, Oxford OX3 9DU, UK
| | - Sonia Contera
- Department of Physics, University of Oxford, Parks Road, Oxford OX1 3PU, UK.
| |
Collapse
|
8
|
Acetazolamide Mitigates Astrocyte Cellular Edema Following Mild Traumatic Brain Injury. Sci Rep 2016; 6:33330. [PMID: 27623738 PMCID: PMC5022024 DOI: 10.1038/srep33330] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Accepted: 08/25/2016] [Indexed: 12/31/2022] Open
Abstract
Non-penetrating or mild traumatic brain injury (mTBI) is commonly experienced in accidents, the battlefield and in full-contact sports. Astrocyte cellular edema is one of the major factors that leads to high morbidity post-mTBI. Various studies have reported an upregulation of aquaporin-4 (AQP4), a water channel protein, following brain injury. AZA is an antiepileptic drug that has been shown to inhibit AQP4 expression and in this study we investigate the drug as a therapeutic to mitigate the extent of mTBI induced cellular edema. We hypothesized that mTBI-mediated astrocyte dysfunction, initiated by increased intracellular volume, could be reduced when treated with AZA. We tested our hypothesis in a three-dimensional in vitro astrocyte model of mTBI. Samples were subject to no stretch (control) or one high-speed stretch (mTBI) injury. AQP4 expression was significantly increased 24 hours after mTBI. mTBI resulted in a significant increase in the cell swelling within 30 min of mTBI, which was significantly reduced in the presence of AZA. Cell death and expression of S100B was significantly reduced when AZA was added shortly before mTBI stretch. Overall, our data point to occurrence of astrocyte swelling immediately following mTBI, and AZA as a promising treatment to mitigate downstream cellular mortality.
Collapse
|
9
|
Rodriguez O, Schaefer ML, Wester B, Lee YC, Boggs N, Conner HA, Merkle AC, Fricke ST, Albanese C, Koliatsos VE. Manganese-Enhanced Magnetic Resonance Imaging as a Diagnostic and Dispositional Tool after Mild-Moderate Blast Traumatic Brain Injury. J Neurotrauma 2016; 33:662-71. [PMID: 26414591 PMCID: PMC4827293 DOI: 10.1089/neu.2015.4002] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Traumatic brain injury (TBI) caused by explosive munitions, known as blast TBI, is the signature injury in recent military conflicts in Iraq and Afghanistan. Diagnostic evaluation of TBI, including blast TBI, is based on clinical history, symptoms, and neuropsychological testing, all of which can result in misdiagnosis or underdiagnosis of this condition, particularly in the case of TBI of mild-to-moderate severity. Prognosis is currently determined by TBI severity, recurrence, and type of pathology, and also may be influenced by promptness of clinical intervention when more effective treatments become available. An important task is prevention of repetitive TBI, particularly when the patient is still symptomatic. For these reasons, the establishment of quantitative biological markers can serve to improve diagnosis and preventative or therapeutic management. In this study, we used a shock-tube model of blast TBI to determine whether manganese-enhanced magnetic resonance imaging (MEMRI) can serve as a tool to accurately and quantitatively diagnose mild-to-moderate blast TBI. Mice were subjected to a 30 psig blast and administered a single dose of MnCl2 intraperitoneally. Longitudinal T1-magnetic resonance imaging (MRI) performed at 6, 24, 48, and 72 h and at 14 and 28 days revealed a marked signal enhancement in the brain of mice exposed to blast, compared with sham controls, at nearly all time-points. Interestingly, when mice were protected with a polycarbonate body shield during blast exposure, the marked increase in contrast was prevented. We conclude that manganese uptake can serve as a quantitative biomarker for TBI and that MEMRI is a minimally-invasive quantitative approach that can aid in the accurate diagnosis and management of blast TBI. In addition, the prevention of the increased uptake of manganese by body protection strongly suggests that the exposure of an individual to blast risk could benefit from the design of improved body armor.
Collapse
Affiliation(s)
- Olga Rodriguez
- Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, DC
| | - Michele L. Schaefer
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Brock Wester
- Research and Exploratory Development Department, Johns Hopkins University, Applied Physics Laboratory, Laurel, Maryland
| | - Yi-Chien Lee
- Department of Oncology, Georgetown University Medical Center, Washington DC
| | - Nathan Boggs
- Research and Exploratory Development Department, Johns Hopkins University, Applied Physics Laboratory, Laurel, Maryland
| | - Howard A. Conner
- Research and Exploratory Development Department, Johns Hopkins University, Applied Physics Laboratory, Laurel, Maryland
| | - Andrew C. Merkle
- Research and Exploratory Development Department, Johns Hopkins University, Applied Physics Laboratory, Laurel, Maryland
| | - Stanley T. Fricke
- Pediatric and Integrative Systems Biology, George Washington University, Washington, DC
| | - Chris Albanese
- Department of Oncology, Georgetown University Medical Center, Washington DC
- Department of Pathology, Georgetown University Medical Center, Washington DC
| | - Vassilis E. Koliatsos
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland
| |
Collapse
|
10
|
Lucke-Wold BP, Logsdon AF, Smith KE, Turner RC, Alkon DL, Tan Z, Naser ZJ, Knotts CM, Huber JD, Rosen CL. Bryostatin-1 Restores Blood Brain Barrier Integrity following Blast-Induced Traumatic Brain Injury. Mol Neurobiol 2015; 52:1119-1134. [PMID: 25301233 PMCID: PMC5000781 DOI: 10.1007/s12035-014-8902-7] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2014] [Accepted: 09/24/2014] [Indexed: 02/08/2023]
Abstract
Recent wars in Iraq and Afghanistan have accounted for an estimated 270,000 blast exposures among military personnel. Blast traumatic brain injury (TBI) is the 'signature injury' of modern warfare. Blood brain barrier (BBB) disruption following blast TBI can lead to long-term and diffuse neuroinflammation. In this study, we investigate for the first time the role of bryostatin-1, a specific protein kinase C (PKC) modulator, in ameliorating BBB breakdown. Thirty seven Sprague-Dawley rats were used for this study. We utilized a clinically relevant and validated blast model to expose animals to moderate blast exposure. Groups included: control, single blast exposure, and single blast exposure + bryostatin-1. Bryostatin-1 was administered i.p. 2.5 mg/kg after blast exposure. Evan's blue, immunohistochemistry, and western blot analysis were performed to assess injury. Evan's blue binds to albumin and is a marker for BBB disruption. The single blast exposure caused an increase in permeability compared to control (t = 4.808, p < 0.05), and a reduction back toward control levels when bryostatin-1 was administered (t = 5.113, p < 0.01). Three important PKC isozymes, PKCα, PKCδ, and PKCε, were co-localized primarily with endothelial cells but not astrocytes. Bryostatin-1 administration reduced toxic PKCα levels back toward control levels (t = 4.559, p < 0.01) and increased the neuroprotective isozyme PKCε (t = 6.102, p < 0.01). Bryostatin-1 caused a significant increase in the tight junction proteins VE-cadherin, ZO-1, and occludin through modulation of PKC activity. Bryostatin-1 ultimately decreased BBB breakdown potentially due to modulation of PKC isozymes. Future work will examine the role of bryostatin-1 in preventing chronic neurodegeneration following repetitive neurotrauma.
Collapse
Affiliation(s)
- Brandon P Lucke-Wold
- Department of Neurosurgery, West Virginia University School of Medicine, Morgantown, WV, 26506, USA
- The Center for Neuroscience, West Virginia University School of Medicine, Morgantown, WV, 26506, USA
| | - Aric F Logsdon
- The Center for Neuroscience, West Virginia University School of Medicine, Morgantown, WV, 26506, USA
- Department of Basic Pharmaceutical Sciences, West Virginia University School of Pharmacy, Morgantown, WV, 26506, USA
| | - Kelly E Smith
- The Center for Neuroscience, West Virginia University School of Medicine, Morgantown, WV, 26506, USA
- Department of Basic Pharmaceutical Sciences, West Virginia University School of Pharmacy, Morgantown, WV, 26506, USA
| | - Ryan C Turner
- Department of Neurosurgery, West Virginia University School of Medicine, Morgantown, WV, 26506, USA
- The Center for Neuroscience, West Virginia University School of Medicine, Morgantown, WV, 26506, USA
| | - Daniel L Alkon
- Blanchette Rockefeller Neurosciences Institute, Morgantown, WV, 26506, USA
| | - Zhenjun Tan
- Department of Neurosurgery, West Virginia University School of Medicine, Morgantown, WV, 26506, USA
- The Center for Neuroscience, West Virginia University School of Medicine, Morgantown, WV, 26506, USA
| | - Zachary J Naser
- Department of Neurosurgery, West Virginia University School of Medicine, Morgantown, WV, 26506, USA
- The Center for Neuroscience, West Virginia University School of Medicine, Morgantown, WV, 26506, USA
- Office of Professional Studies in Health Sciences, Drexel University College of Medicine, Philadelphia, PA, 19102, USA
| | - Chelsea M Knotts
- Department of Neurosurgery, West Virginia University School of Medicine, Morgantown, WV, 26506, USA
| | - Jason D Huber
- The Center for Neuroscience, West Virginia University School of Medicine, Morgantown, WV, 26506, USA
- Department of Basic Pharmaceutical Sciences, West Virginia University School of Pharmacy, Morgantown, WV, 26506, USA
| | - Charles L Rosen
- Department of Neurosurgery, West Virginia University School of Medicine, Morgantown, WV, 26506, USA.
- The Center for Neuroscience, West Virginia University School of Medicine, Morgantown, WV, 26506, USA.
- Department of Neurosurgery, West Virginia University School of Medicine, One Medical Center Drive, Suite 4300, Health Sciences Center, PO Box 9183, Morgantown, WV, 26506-9183, USA.
| |
Collapse
|
11
|
Traumatic Brain Injury and the Neuronal Microenvironment: A Potential Role for Neuropathological Mechanotransduction. Neuron 2015; 85:1177-92. [DOI: 10.1016/j.neuron.2015.02.041] [Citation(s) in RCA: 116] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
|
12
|
Chen LJ, Wang YJ, Chen JR, Tseng GF. NMDA receptor triggered molecular cascade underlies compression-induced rapid dendritic spine plasticity in cortical neurons. Exp Neurol 2015; 266:86-98. [PMID: 25708984 DOI: 10.1016/j.expneurol.2015.02.014] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2014] [Revised: 12/05/2014] [Accepted: 02/09/2015] [Indexed: 10/24/2022]
Abstract
Compression causes the reduction of dendritic spines of underlying adult cortical pyramidal neurons but the mechanisms remain at large. Using a rat epidural cerebral compression model, dendritic spines on the more superficial-lying layer III pyramidal neurons were found quickly reduced in 12h, while those on the deep-located layer V pyramidal neurons were reduced slightly later, starting 1day following compression. No change in the synaptic vesicle markers synaptophysin and vesicular glutamate transporter 1 suggest no change in afferents. Postsynaptically, N-methyl-d-aspartate (NMDA) receptor trafficking to synaptic membrane was detected in 10min and lasting to 1day after compression. Translocation of calcineurin to synapses and enhancement of its enzymatic activity were detected within 10min as well. These suggest that compression rapidly activated NMDA receptors to increase postsynaptic calcium, which then activated the phosphatase calcineurin. In line with this, dephosphorylation and activation of the actin severing protein cofilin, and the consequent depolymerization of actin were all identified in the compressed cortex within matching time frames. Antagonizing NMDA receptors with MK801 before compression prevented this cascade of events, including NR1 mobilization, calcineurin activation and actin depolymerization, in the affected cortex. Morphologically, MK801 pretreatment prevented the loss of dendritic spines on the compressed cortical pyramidal neurons as well. In short, we demonstrated, for the first time, mechanisms underlying the rapid compression-induced cortical neuronal dendritic spine plasticity. In addition, the mechanical force of compression appears to activate NMDA receptors to initiate a rapid postsynaptic molecular cascade to trim dendritic spines on the compressed cortical pyramidal neurons within half a day.
Collapse
Affiliation(s)
- Li-Jin Chen
- Department of Anatomy, College of Medicine, Tzu-Chi University, Hualien, Taiwan
| | - Yueh-Jan Wang
- Department of Anatomy, College of Medicine, Tzu-Chi University, Hualien, Taiwan
| | - Jeng-Rung Chen
- Department of Veterinary Medicine, College of Veterinary Medicine, National Chung-Hsing University, Taichung, Taiwan
| | - Guo-Fang Tseng
- Department of Anatomy, College of Medicine, Tzu-Chi University, Hualien, Taiwan.
| |
Collapse
|
13
|
Single-neuron NMDA receptor phenotype influences neuronal rewiring and reintegration following traumatic injury. J Neurosci 2014; 34:4200-13. [PMID: 24647941 DOI: 10.1523/jneurosci.4172-13.2014] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Alterations in the activity of neural circuits are a common consequence of traumatic brain injury (TBI), but the relationship between single-neuron properties and the aggregate network behavior is not well understood. We recently reported that the GluN2B-containing NMDA receptors (NMDARs) are key in mediating mechanical forces during TBI, and that TBI produces a complex change in the functional connectivity of neuronal networks. Here, we evaluated whether cell-to-cell heterogeneity in the connectivity and aggregate contribution of GluN2B receptors to [Ca(2+)]i before injury influenced the functional rewiring, spontaneous activity, and network plasticity following injury using primary rat cortical dissociated neurons. We found that the functional connectivity of a neuron to its neighbors, combined with the relative influx of calcium through distinct NMDAR subtypes, together contributed to the individual neuronal response to trauma. Specifically, individual neurons whose [Ca(2+)]i oscillations were largely due to GluN2B NMDAR activation lost many of their functional targets 1 h following injury. In comparison, neurons with large GluN2A contribution or neurons with high functional connectivity both independently protected against injury-induced loss in connectivity. Mechanistically, we found that traumatic injury resulted in increased uncorrelated network activity, an effect linked to reduction of the voltage-sensitive Mg(2+) block of GluN2B-containing NMDARs. This uncorrelated activation of GluN2B subtypes after injury significantly limited the potential for network remodeling in response to a plasticity stimulus. Together, our data suggest that two single-cell characteristics, the aggregate contribution of NMDAR subtypes and the number of functional connections, influence network structure following traumatic injury.
Collapse
|
14
|
Yuan Y, Pan S, Sun Z, Dan Q, Liu J. Brain-derived neurotrophic factor-modified umbilical cord mesenchymal stem cell transplantation improves neurological deficits in rats with traumatic brain injury. Int J Neurosci 2013; 124:524-31. [DOI: 10.3109/00207454.2013.859144] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
|
15
|
Gurkoff G, Shahlaie K, Lyeth B, Berman R. Voltage-gated calcium channel antagonists and traumatic brain injury. Pharmaceuticals (Basel) 2013; 6:788-812. [PMID: 24276315 PMCID: PMC3816709 DOI: 10.3390/ph6070788] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2013] [Revised: 06/06/2013] [Accepted: 06/06/2013] [Indexed: 01/17/2023] Open
Abstract
Traumatic brain injury (TBI) is a leading cause of death and disability in the United States. Despite more than 30 years of research, no pharmacological agents have been identified that improve neurological function following TBI. However, several lines of research described in this review provide support for further development of voltage gated calcium channel (VGCC) antagonists as potential therapeutic agents. Following TBI, neurons and astrocytes experience a rapid and sometimes enduring increase in intracellular calcium ([Ca2+]i). These fluxes in [Ca2+]i drive not only apoptotic and necrotic cell death, but also can lead to long-term cell dysfunction in surviving cells. In a limited number of in vitro experiments, both L-type and N-type VGCC antagonists successfully reduced calcium loads as well as neuronal and astrocytic cell death following mechanical injury. In rodent models of TBI, administration of VGCC antagonists reduced cell death and improved cognitive function. It is clear that there is a critical need to find effective therapeutics and rational drug delivery strategies for the management and treatment of TBI, and we believe that further investigation of VGCC antagonists should be pursued before ruling out the possibility of successful translation to the clinic.
Collapse
Affiliation(s)
- Gene Gurkoff
- Department of Neurological Surgery, One Shields Avenue, University of California, Davis, CA 95616, USA; E-Mails: (K.S.); (B.L.); (R.B.)
- NSF Center for Biophotonics Science and Technology, Suite 2700 Stockton Blvd, Suite 1400, Sacramento, CA, 95817, USA
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +1-530-754-7501; Fax: +1-530-754-5125
| | - Kiarash Shahlaie
- Department of Neurological Surgery, One Shields Avenue, University of California, Davis, CA 95616, USA; E-Mails: (K.S.); (B.L.); (R.B.)
| | - Bruce Lyeth
- Department of Neurological Surgery, One Shields Avenue, University of California, Davis, CA 95616, USA; E-Mails: (K.S.); (B.L.); (R.B.)
| | - Robert Berman
- Department of Neurological Surgery, One Shields Avenue, University of California, Davis, CA 95616, USA; E-Mails: (K.S.); (B.L.); (R.B.)
| |
Collapse
|
16
|
Mesfin MN, von Reyn CR, Mott RE, Putt ME, Meaney DF. In vitro stretch injury induces time- and severity-dependent alterations of STEP phosphorylation and proteolysis in neurons. J Neurotrauma 2012; 29:1982-98. [PMID: 22435660 DOI: 10.1089/neu.2011.2253] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Striatal-enriched tyrosine phosphatase (STEP) has been identified as a component of physiological and pathophysiological signaling pathways mediated by N-methyl-d-aspartate (NMDA) receptor/calcineurin/calpain activation. Activation of these pathways produces a subsequent change in STEP isoform expression or activation via dephosphorylation. In this study, we evaluated changes in STEP phosphorylation and proteolysis in dissociated cortical neurons after sublethal and lethal mechanical injury using an in vitro stretch injury device. Sublethal stretch injury produces minimal changes in STEP phosphorylation at early time points, and increased STEP phosphorylation at 24 h that is blocked by the NMDA-receptor antagonist APV, the calcineurin-inhibitor FK506, and the sodium channel blocker tetrodotoxin. Lethal stretch injury produces rapid STEP dephosphorylation via NR2B-containing NMDA receptors, but not calcineurin, and a subsequent biphasic phosphorylation pattern. STEP(61) expression progressively increases after sublethal stretch with no change in calpain-mediated STEP(33) formation, while lethal stretch injury results in STEP(33) formation via a NR2B-containing NMDA receptor pathway within 1 h of injury. Blocking calpain activation in the initial 30 min after stretch injury increases the ratio of active STEP in cells and blocks STEP(33) formation, suggesting that STEP is an early substrate of calpain after mechanical injury. There is a strong correlation between the amount of STEP(33) formed and the degree of cell death observed after lethal stretch injury. In summary, these data demonstrate that previously characterized pathways of STEP regulation via the NMDA receptor are generally conserved in mechanical injury, and suggest that calpain-mediated cleavage of STEP(33) should be further examined as an early marker of neuronal fate after stretch injury.
Collapse
Affiliation(s)
- Mahlet N Mesfin
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104, USA
| | | | | | | | | |
Collapse
|
17
|
Weber JT. Altered calcium signaling following traumatic brain injury. Front Pharmacol 2012; 3:60. [PMID: 22518104 PMCID: PMC3324969 DOI: 10.3389/fphar.2012.00060] [Citation(s) in RCA: 138] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2012] [Accepted: 03/24/2012] [Indexed: 01/10/2023] Open
Abstract
Cell death and dysfunction after traumatic brain injury (TBI) is caused by a primary phase, related to direct mechanical disruption of the brain, and a secondary phase which consists of delayed events initiated at the time of the physical insult. Arguably, the calcium ion contributes greatly to the delayed cell damage and death after TBI. A large, sustained influx of calcium into cells can initiate cell death signaling cascades, through activation of several degradative enzymes, such as proteases and endonucleases. However, a sustained level of intracellular free calcium is not necessarily lethal, but the specific route of calcium entry may couple calcium directly to cell death pathways. Other sources of calcium, such as intracellular calcium stores, can also contribute to cell damage. In addition, calcium-mediated signal transduction pathways in neurons may be perturbed following injury. These latter types of alterations may contribute to abnormal physiology in neurons that do not necessarily die after a traumatic episode. This review provides an overview of experimental evidence that has led to our current understanding of the role of calcium signaling in death and dysfunction following TBI.
Collapse
Affiliation(s)
- John T. Weber
- School of Pharmacy and Division of BioMedical Sciences, Faculty of Medicine, Memorial University of NewfoundlandSt. John’s, NL, Canada
| |
Collapse
|
18
|
von Reyn CR, Mott RE, Siman R, Smith DH, Meaney DF. Mechanisms of calpain mediated proteolysis of voltage gated sodium channel α-subunits following in vitro dynamic stretch injury. J Neurochem 2012; 121:793-805. [PMID: 22428606 DOI: 10.1111/j.1471-4159.2012.07735.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Although enhanced calpain activity is well documented after traumatic brain injury (TBI), the pathways targeting specific substrate proteolysis are less defined. Our past work demonstrated that calpain cleaves voltage gated sodium channel (NaCh) α-subunits in an in vitro TBI model. In this study, we investigated the pathways leading to NaCh cleavage utilizing our previously characterized in vitro TBI model, and determined the location of calpain activation within neuronal regions following stretch injury to micropatterned cultures. Calpain specific breakdown products of α-spectrin appeared within axonal, dendritic, and somatic regions 6 h after injury, concurrent with the appearance of NaCh α-subunit proteolysis in both whole cell or enriched axonal preparations. Direct pharmacological activation of either NMDA receptors (NMDArs) or NaChs resulted in NaCh proteolysis. Likewise, a chronic (6 h) dual inhibition of NMDArs/NaChs but not L-type voltage gated calcium channels significantly reduced NaCh proteolysis 6 h after mechanical injury. Interestingly, an early, transient (30 min) inhibition of NMDArs alone significantly reduced NaCh proteolysis. Although a chronic inhibition of calpain significantly reduced proteolysis, a transient inhibition of calpain immediately after injury failed to significantly attenuate NaCh proteolysis. These data suggest that both NMDArs and NaChs are key contributors to calpain activation after mechanical injury, and that a larger temporal window of sustained calpain activation needs consideration in developing effective treatments for TBI.
Collapse
|
19
|
Spaethling J, Le L, Meaney DF. NMDA receptor mediated phosphorylation of GluR1 subunits contributes to the appearance of calcium-permeable AMPA receptors after mechanical stretch injury. Neurobiol Dis 2012; 46:646-54. [PMID: 22426393 DOI: 10.1016/j.nbd.2012.03.003] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2011] [Revised: 01/30/2012] [Accepted: 03/01/2012] [Indexed: 10/28/2022] Open
Abstract
Alterations in neuronal cytosolic calcium is a key mediator of the traumatic brain injury (TBI) pathobiology, but less is known of the role and source of calcium in shaping early changes in synaptic receptors and neural circuits after TBI. In this study, we examined the calcium source and potential phosphorylation events leading to insertion of calcium-permeable AMPARs (CP-AMPARs) after in vitro traumatic brain injury, a receptor subtype that influences neural circuit dynamics for hours to days following injury. We found that both synaptic and NR2B-containing NMDARs contribute significantly to the calcium influx following stretch injury. Moreover, an early and sustained phosphorylation of the S-831 site of the GluR1 subunit appeared after mechanical injury, and this phosphorylation was blocked with the inhibition of either synaptic NMDARs or NR2B-containing NMDARs. In comparison, mechanical injury led to no significant change in the S-845 phosphorylation of the GluR1 subunit. Although no change in S-845 phosphorylation appeared in injured cultures, we observed that inhibition of NR2B-containing NMDARs significantly increased S-845 phosphorylation 1h after injury while blockade of synaptic NMDARs did not change S-845 phosphorylation at any time point following injury. These findings show that a broad class of NMDARs are activated in parallel and that targeting either subpopulation will reverse some of the consequences of mechanical injury, providing distinct paths to treat the effects of mechanical injury on neural circuits after TBI.
Collapse
Affiliation(s)
- Jennifer Spaethling
- Department of Pharmacology, University of Pennsylvania, Philadelphia, PA 19104, United States
| | | | | |
Collapse
|
20
|
Choo AM, Geddes-Klein DM, Hockenberry A, Scarsella D, Mesfin MN, Singh P, Patel TP, Meaney DF. NR2A and NR2B subunits differentially mediate MAP kinase signaling and mitochondrial morphology following excitotoxic insult. Neurochem Int 2012; 60:506-16. [PMID: 22366650 DOI: 10.1016/j.neuint.2012.02.007] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2011] [Revised: 01/13/2012] [Accepted: 02/04/2012] [Indexed: 11/17/2022]
Abstract
NMDA receptors are essential for neurotransmission and key mediators of synaptic signaling, but they can also trigger deleterious degenerative processes that lead to cell death. Growing evidence suggests that selective blockade of the heterogeneous subunits that comprise the NMDA receptor may enable better control of pharmacotherapies for treating neurological diseases and injuries. We investigated the relationship between NMDAR activation, MAPK signaling, and mitochondrial shape following an excitotoxic insult. NR2A- and NR2B-containing NMDARs differentially mediated acute changes in cytosolic calcium, alterations in mitochondrial morphology, and phosphorylation of the MAPKs ERK and JNK. Activation of NR2A-containing NMDARs was associated with JNK phosphorylation that was neuroprotective in neuronal cultures subjected to excitotoxicity. In contrast, activation of NR2B-containing NMDARs triggered calcium accumulation in mitochondria that was strongly associated with mitochondrial swelling and neuronal cell death. Indeed, while blockade of NR2B-containing receptors was neuroprotective, this protection was lost when NR2A-initiated JNK phosphorylation was inhibited. Given the modest selectivity of the NR2A inhibitor, NVP-AAM077, the results highlight the significance of the relative, rather than absolute, activation of these two NMDA subtypes in modulating cell death pathways. Therefore, the balance between concurrent activation of NR2B-containing and NR2A-containing NMDARs dictates neuronal fate following excitotoxicity.
Collapse
Affiliation(s)
- Anthony M Choo
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA
| | | | | | | | | | | | | | | |
Collapse
|
21
|
Singh P, Doshi S, Spaethling JM, Hockenberry AJ, Patel TP, Geddes-Klein DM, Lynch DR, Meaney DF. N-methyl-D-aspartate receptor mechanosensitivity is governed by C terminus of NR2B subunit. J Biol Chem 2011; 287:4348-59. [PMID: 22179603 DOI: 10.1074/jbc.m111.253740] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
N-methyl-D-aspartate receptors (NMDARs), critical mediators of both physiologic and pathologic neurological signaling, have previously been shown to be sensitive to mechanical stretch through the loss of its native Mg(2+) block. However, the regulation of this mechanosensitivity has yet to be further explored. Furthermore, as it has become apparent that NMDAR-mediated signaling is dependent on specific NMDAR subtypes, as governed by the identity of the NR2 subunit, a crucial unanswered question is the role of subunit composition in observed NMDAR mechanosensitivity. Here, we used a recombinant system to assess the mechanosensitivity of specific subtypes and demonstrate that the mechanosensitive property is uniquely governed by the NR2B subunit. NR1/NR2B NMDARs displayed significant stretch sensitivity, whereas NR1/NR2A NMDARs did not respond to stretch. Furthermore, NR2B mechanosensitivity was regulated by PKC activity, because PKC inhibition reduced stretch responses in transfected HEK 293 cells and primary cortical neurons. Finally, using NR2B point mutations, we identified a PKC phosphorylation site, Ser-1323 on NR2B, as a unique critical regulator of stretch sensitivity. These data suggest that the selective mechanosensitivity of NR2B can significantly impact neuronal response to traumatic brain injury and illustrate that the mechanical tone of the neuron can be dynamically regulated by PKC activity.
Collapse
Affiliation(s)
- Pallab Singh
- Department of Neurology, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | | | | | | | | | | | | | | |
Collapse
|
22
|
Patel TP, Ventre SC, Meaney DF. Dynamic changes in neural circuit topology following mild mechanical injury in vitro. Ann Biomed Eng 2011; 40:23-36. [PMID: 21994056 DOI: 10.1007/s10439-011-0390-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2011] [Accepted: 08/24/2011] [Indexed: 11/26/2022]
Abstract
Despite its enormous incidence, mild traumatic brain injury is not well understood. One aspect that needs more definition is how the mechanical energy during injury affects neural circuit function. Recent developments in cellular imaging probes provide an opportunity to assess the dynamic state of neural networks with single-cell resolution. In this article, we developed imaging methods to assess the state of dissociated cortical networks exposed to mild injury. We estimated the imaging conditions needed to achieve accurate measures of network properties, and applied these methodologies to evaluate if mild mechanical injury to cortical neurons produces graded changes to either spontaneous network activity or altered network topology. We found that modest injury produced a transient increase in calcium activity that dissipated within 1 h after injury. Alternatively, moderate mechanical injury produced immediate disruption in network synchrony, loss in excitatory tone, and increased modular topology. A calcium-activated neutral protease (calpain) was a key intermediary in these changes; blocking calpain activation restored the network nearly completely to its pre-injury state. Together, these findings show a more complex change in neural circuit behavior than previously reported for mild mechanical injury, and highlight at least one important early mechanism responsible for these changes.
Collapse
Affiliation(s)
- Tapan P Patel
- Department of Bioengineering, University of Pennsylvania, 220 S 33rd St, Philadelphia, PA 19104, USA
| | | | | |
Collapse
|
23
|
Luo P, Fei F, Zhang L, Qu Y, Fei Z. The role of glutamate receptors in traumatic brain injury: implications for postsynaptic density in pathophysiology. Brain Res Bull 2011; 85:313-20. [PMID: 21605633 DOI: 10.1016/j.brainresbull.2011.05.004] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2010] [Revised: 04/27/2011] [Accepted: 05/08/2011] [Indexed: 11/25/2022]
Abstract
Traumatic brain injury (TBI) is the major cause of death and disability, and the incidence of TBI continues to increase rapidly. In recent years, increasing attention has been paid to an important structure at the postsynaptic membrane: the postsynaptic density (PSD). Glutamate receptors, as major components of the PSD, are highly responsive to alterations in the glutamate concentration at excitatory synapses and activate intracellular signal transduction via calcium and other second messengers following TBI. PSD scaffold proteins (PSD-95, Homer, and Shank), which anchor glutamate receptors and form a network structure, also have potential effects on these downstream signaling pathways. The changes in the function and structure of these major PSD proteins are also induced by TBI, indicating that there is a more complicated mechanism associated with PSD proteins in the pathophysiological process of TBI.
Collapse
Affiliation(s)
- Peng Luo
- Department of Neurosurgery, Xijing Hospital, Fourth Military Medical University, 15 Changle Xi Road, Xi'an 710032, PR China
| | | | | | | | | |
Collapse
|
24
|
Monnerie H, Tang-Schomer MD, Iwata A, Smith DH, Kim HA, Le Roux PD. Dendritic alterations after dynamic axonal stretch injury in vitro. Exp Neurol 2010; 224:415-23. [PMID: 20478308 DOI: 10.1016/j.expneurol.2010.05.001] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2010] [Revised: 04/29/2010] [Accepted: 05/03/2010] [Indexed: 10/19/2022]
Abstract
Traumatic axonal injury (TAI) is the most common and important pathology of traumatic brain injury (TBI). However, little is known about potential indirect effects of TAI on dendrites. In this study, we used a well-established in vitro model of axonal stretch injury to investigate TAI-induced changes in dendrite morphology. Axons bridging two separated rat cortical neuron populations plated on a deformable substrate were used to create a zone of isolated stretch injury to axons. Following injury, we observed the formation of dendritic alterations or beading along the dendrite shaft. Dendritic beading formed within minutes after stretch then subsided over time. Pharmacological experiments revealed a sodium-dependent mechanism, while removing extracellular calcium exacerbated TAI's effect on dendrites. In addition, blocking ionotropic glutamate receptors with the N-methyl-d-aspartate (NMDA) receptor antagonist MK-801 prevented dendritic beading. These results demonstrate that axon mechanical injury directly affects dendrite morphology, highlighting an important bystander effect of TAI. The data also imply that TAI may alter dendrite structure and plasticity in vivo. An understanding of TAI's effect on dendrites is important since proper dendrite function is crucial for normal brain function and recovery after injury.
Collapse
Affiliation(s)
- Hubert Monnerie
- Department of Neurosurgery, University of Pennsylvania, Philadelphia, PA 19107, USA
| | | | | | | | | | | |
Collapse
|
25
|
Mechanical membrane injury induces axonal beading through localized activation of calpain. Exp Neurol 2009; 219:553-61. [PMID: 19619536 DOI: 10.1016/j.expneurol.2009.07.014] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2009] [Revised: 07/09/2009] [Accepted: 07/13/2009] [Indexed: 12/31/2022]
Abstract
Diffuse axonal injury (DAI), a major component of traumatic brain injury, is characterized by a sequence of neurochemical reactions initiated at the time of trauma and resulting in axonal degeneration and cell death. Calcium influx through mechanically induced axolemmal pores and subsequent activation of calpains are thought to be responsible for the cytoskeletal damage leading to impaired axonal transport. Focal disruption of cytoskeleton accompanied by the accumulation of transported membranous cargo leads to axonal beading which is the characteristic morphology of DAI. By applying fluid shear stress injury on cultured primary neurons, acute calcium (Ca(2+)) and calpain responses of axons to mechanical trauma were investigated. Intracellular Ca(2+) concentration ([Ca(2+)](i)) shows a steady increase following injury that can be blocked by sealing membrane pores with Poloxamer 188 and by chelating intra- or extracellular Ca(2+). Calpain activity increases in response to mechanical injury and this increase depends on Ca(2+) availability and on axolemmal permeability. Both the [Ca(2+)](i) increase and calpain activity exhibit focal peaks along the axons which co-localize with mitochondria and predict future axonal bead locations. These findings suggest that mechanoporation may be the initiating mechanism resulting in ensuing calcium fluxes and subsequent calpain activity and that post-injury membrane repair may be a valid therapeutic approach for acute intervention in DAI.
Collapse
|
26
|
Wang Z, Deng Q, Zhang X, Zhang J. Treatment of Injured Neurons with Bone Marrow Stem Cells Cotransfected by hTERT and Ad-BDNF In Vitro. J Mol Neurosci 2009; 38:265-72. [DOI: 10.1007/s12031-009-9208-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2008] [Accepted: 04/27/2009] [Indexed: 11/28/2022]
|
27
|
Spaethling JM, Klein DM, Singh P, Meaney DF. Calcium-permeable AMPA receptors appear in cortical neurons after traumatic mechanical injury and contribute to neuronal fate. J Neurotrauma 2009; 25:1207-16. [PMID: 18986222 DOI: 10.1089/neu.2008.0532] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Traumatic brain injury (TBI) is one of the most disabling injuries in the population, with 1.5 million Americans new cases each year and 5.3 million Americans overall requiring long-term daily care as a result of their injuries. One critical aspect in developing effective treatments for TBI is determining if new, specific receptor populations emerge in the early phase after injury that can subsequently be targeted to reduce neuronal death after injury. One specific glutamate receptor subtype, the calcium-permeable AMPA receptor (CP-AMPAR), is becoming increasingly recognized for its role in physiological and pathophysiological processes. Although present in relatively low levels in the mature brain, recent studies show that CP-AMPARs can appear following ischemic brain injury or status epilepticus, and the mechanisms that regulate the appearance of these receptors include alterations in transcription, RNA editing, and receptor trafficking. In this report, we use an in vitro model of TBI to show a gradual appearance of CP-AMPARs four hours following injury to cortical neurons. Moreover, the appearance of these receptors is mediated by the phosphorylation of CaMKIIalpha following injury. Selectively blocking CP-AMPARs after mechanical injury leads to a significant reduction in the cell death that occurs 24 h following injury in untreated controls, and is similar in protection offered by broad-spectrum NMDA and AMPA receptor antagonists. These data point to a potentially new and more targeted therapeutic approach for treating TBI.
Collapse
Affiliation(s)
- Jennifer M Spaethling
- Department of Pharmacology, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6321, USA
| | | | | | | |
Collapse
|
28
|
Abstract
Traumatic brain injury is a leading cause of morbidity and death in both industrialized and developing countries. To date, there is no targeted pharmacological treatment that effectively limits the progression of secondary injury. The delayed progression of deterioration of grey and white matter gives hope that a meaningful intervention can be applied in a realistic timeframe following initial trauma. In this review we discuss new insights into the subcellular mechanisms of secondary injury that have highlighted numerous potential targets for intervention.
Collapse
Affiliation(s)
- Eugene Park
- Cara Phelan Centre for Trauma Research, Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, Ont
| | | | | |
Collapse
|
29
|
Spaethling JM, Geddes-Klein DM, Miller WJ, von Reyn CR, Singh P, Mesfin M, Bernstein SJ, Meaney DF. Linking impact to cellular and molecular sequelae of CNS injury: modeling in vivo complexity with in vitro simplicity. PROGRESS IN BRAIN RESEARCH 2007; 161:27-39. [PMID: 17618968 DOI: 10.1016/s0079-6123(06)61003-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Traumatic brain injury (TBI) represents one of most common disorders to the central nervous system (CNS). Despite significant efforts, though, an effective clinical treatment for TBI is not yet available. The complexity of human TBI is modeled with a broad group of experimental models, with each model matching some aspect of the human condition. In the past 15 years, these in vivo models were complemented with a group of in vitro models, with these in vitro models allowing investigators to more precisely identify the mechanism(s) of TBI, the different intracellular events that occur in acute period following injury, and the possible treatment of this injury in vitro. In this paper, we review the available in vitro models to study TBI, discuss their biomechanical basis for human TBI, and review the findings from these in vitro models. Finally, we synthesize the current knowledge and point out possible future directions for this group of models, especially in the effort toward developing new therapies for the traumatically brain injured patient.
Collapse
Affiliation(s)
- Jennifer M Spaethling
- Department of Bioengineering, University of Pennsylvania, 3320 Smith Walk, Philadelphia, PA 19104-6392, USA
| | | | | | | | | | | | | | | |
Collapse
|
30
|
Kloda A, Lua L, Hall R, Adams DJ, Martinac B. Liposome reconstitution and modulation of recombinant N-methyl-D-aspartate receptor channels by membrane stretch. Proc Natl Acad Sci U S A 2007; 104:1540-5. [PMID: 17242368 PMCID: PMC1780071 DOI: 10.1073/pnas.0609649104] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2006] [Indexed: 11/18/2022] Open
Abstract
In this study, the heteromeric N-methyl-D-aspartate (NMDA) receptor channels composed of NR1a and NR2A subunits were expressed, purified, reconstituted into liposomes, and characterized by using the patch clamp technique. The protein exhibited the expected electrophysiological profile of activation by glutamate and glycine and internal Mg2+ blockade. We demonstrated that the mechanical energy transmitted to membrane-bound NMDA receptor channels can be exerted directly by tension developed in the lipid bilayer. Membrane stretch and application of arachidonic acid potentiated currents through NMDA receptor channels in the presence of intracellular Mg2+. The correlation of membrane tension induced by either mechanical or chemical stimuli with the physiological Mg2+ block of the channel suggests that the synaptic transmission can be altered if NMDA receptor complexes experience local changes in bilayer thickness caused by dynamic targeting to lipid microdomains, electrocompression, or chemical modification of the cell membranes. The ability to study gating properties of NMDA receptor channels in artificial bilayers should prove useful in further study of structure-function relationships and facilitate discoveries of new therapeutic agents for treatment of glutamate-mediated excitotoxicity or analgesic therapies.
Collapse
Affiliation(s)
| | - Linda Lua
- SRC Protein Expression Facility, Institute for Molecular Bioscience, University of Queensland, Brisbane, Queensland 4072, Australia
| | - Rhonda Hall
- SRC Protein Expression Facility, Institute for Molecular Bioscience, University of Queensland, Brisbane, Queensland 4072, Australia
| | | | | |
Collapse
|