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Oganezovi N, Lagani V, Kikvidze M, Gamkrelidze G, Tsverava L, Lepsveridze E, Kelly KM, Solomonia R. Long-term effects of myo-inositol on traumatic brain injury: Epigenomic and transcriptomic studies. IBRO Neurosci Rep 2024; 16:291-299. [PMID: 38374956 PMCID: PMC10875114 DOI: 10.1016/j.ibneur.2024.01.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Accepted: 01/27/2024] [Indexed: 02/21/2024] Open
Abstract
Background and purpose Traumatic brain injury (TBI) and its consequences remain great challenges for neurology. Consequences of TBI are associated with various alterations in the brain but little is known about long-term changes of epigenetic DNA methylation patterns. Moreover, nothing is known about potential treatments that can alter these epigenetic changes in beneficial ways. Therefore, we have examined myo-inositol (MI), which has positive effects on several pathological conditions. Methods TBI was induced in mice by controlled cortical impact (CCI). One group of CCI animals received saline injections for two months (TBI+SAL), another CCI group received MI treatment (TBI+MI) for the same period and one group served as a sham-operated control. Mice were sacrificed 4 months after CCI and changes in DNA methylome and transcriptomes were examined. Results For the first time we: (i) provide comprehensive map of long-term DNA methylation changes after CCI in the hippocampus; (ii) identify differences by methylation sites between the groups; (iii) characterize transcriptome changes; (iv) provide association between DNA methylation sites and gene expression. MI treatment is linked with upregulation of genes covering 33 biological processes, involved in immune response and inflammation. In support of these findings, we have shown that expression of BATF2, a transcription factor involved in immune-regulatory networks, is upregulated in the hippocampus of the TBI+MI group where the BATF2 gene is demethylated. Conclusion TBI is followed by long-term epigenetic and transcriptomic changes in hippocampus. MI treatment has a significant effect on these processes by modulation of immune response and biological pathways of inflammation.
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Affiliation(s)
- Nino Oganezovi
- School of Natural Sciences and Medicine, Institute of Chemical Biology, Ilia State University, Tbilisi, Georgia
| | - Vincenzo Lagani
- School of Natural Sciences and Medicine, Institute of Chemical Biology, Ilia State University, Tbilisi, Georgia
- Biological and Environmental Sciences and Engineering Division, King Abdullah University of Science and Technology, Thuwal 23955, Saudi Arabia
| | - Marine Kikvidze
- School of Natural Sciences and Medicine, Institute of Chemical Biology, Ilia State University, Tbilisi, Georgia
| | - Georgi Gamkrelidze
- School of Natural Sciences and Medicine, Institute of Chemical Biology, Ilia State University, Tbilisi, Georgia
| | - Lia Tsverava
- School of Natural Sciences and Medicine, Institute of Chemical Biology, Ilia State University, Tbilisi, Georgia
- Iv. Beritashvili Centre of Experimental Biomedicine, Tbilisi, Georgia
| | - Eka Lepsveridze
- School of Natural Sciences and Medicine, Institute of Chemical Biology, Ilia State University, Tbilisi, Georgia
| | - Kevin M. Kelly
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA, United States
- Department of Neurology, Philadelphia, PA, United States
- Department of Neurology, Allegheny General Hospital, Pittsburgh, PA, United States
- Center for Neuroscience Research, Allegheny Health Network Research Institute, Pittsburgh, PA, United States, Drexel University College of Medicine, Philadelphia, PA, United States
| | - Revaz Solomonia
- School of Natural Sciences and Medicine, Institute of Chemical Biology, Ilia State University, Tbilisi, Georgia
- Iv. Beritashvili Centre of Experimental Biomedicine, Tbilisi, Georgia
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2
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Witkin JM, Shafique H, Cerne R, Smith JL, Marini AM, Lipsky RH, Delery E. Mechanistic and therapeutic relationships of traumatic brain injury and γ-amino-butyric acid (GABA). Pharmacol Ther 2024; 256:108609. [PMID: 38369062 DOI: 10.1016/j.pharmthera.2024.108609] [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: 10/28/2023] [Revised: 01/18/2024] [Accepted: 02/01/2024] [Indexed: 02/20/2024]
Abstract
Traumatic brain injury (TBI) is a highly prevalent medical condition for which no medications specific for the prophylaxis or treatment of the condition as a whole exist. The spectrum of symptoms includes coma, headache, seizures, cognitive impairment, depression, and anxiety. Although it has been known for years that the inhibitory neurotransmitter γ-amino-butyric acid (GABA) is involved in TBI, no novel therapeutics based upon this mechanism have been introduced into clinical practice. We review the neuroanatomical, neurophysiological, neurochemical, and neuropharmacological relationships of GABA neurotransmission to TBI with a view toward new potential GABA-based medicines. The long-standing idea that excitatory and inhibitory (GABA and others) balances are disrupted by TBI is supported by the experimental data but has failed to invent novel methods of restoring this balance. The slow progress in advancing new treatments is due to the complexity of the disorder that encompasses multiple dynamically interacting biological processes including hemodynamic and metabolic systems, neurodegeneration and neurogenesis, major disruptions in neural networks and axons, frank brain lesions, and a multitude of symptoms that have differential neuronal and neurohormonal regulatory mechanisms. Although the current and ongoing clinical studies include GABAergic drugs, no novel GABA compounds are being explored. It is suggested that filling the gap in understanding the roles played by specific GABAA receptor configurations within specific neuronal circuits could help define new therapeutic approaches. Further research into the temporal and spatial delivery of GABA modulators should also be useful. Along with GABA modulation, research into the sequencing of GABA and non-GABA treatments will be needed.
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Affiliation(s)
- Jeffrey M Witkin
- Laboratory of Antiepileptic Drug Discovery, Ascension St. Vincent Hospital, Indianapolis, IN, USA; Departments of Neuroscience and Trauma Research, Ascension St. Vincent Hospital, Indianapolis, IN, USA; RespireRx Pharmaceuticals Inc, Glen Rock, NJ, USA.
| | | | - Rok Cerne
- Laboratory of Antiepileptic Drug Discovery, Ascension St. Vincent Hospital, Indianapolis, IN, USA; RespireRx Pharmaceuticals Inc, Glen Rock, NJ, USA; Department of Anatomy and Cell Biology, Indiana University/Purdue University, Indianapolis, IN, USA
| | - Jodi L Smith
- Laboratory of Antiepileptic Drug Discovery, Ascension St. Vincent Hospital, Indianapolis, IN, USA
| | - Ann M Marini
- Department of Neurology, Program in Neuroscience, and Molecular and Cellular Biology Program, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| | - Robert H Lipsky
- Department of Neurology, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| | - Elizabeth Delery
- College of Osteopathic Medicine, Marian University, Indianapolis, IN, USA.
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McNerney MW, Gurkoff GG, Beard C, Berryhill ME. The Rehabilitation Potential of Neurostimulation for Mild Traumatic Brain Injury in Animal and Human Studies. Brain Sci 2023; 13:1402. [PMID: 37891771 PMCID: PMC10605899 DOI: 10.3390/brainsci13101402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Revised: 09/25/2023] [Accepted: 09/28/2023] [Indexed: 10/29/2023] Open
Abstract
Neurostimulation carries high therapeutic potential, accompanied by an excellent safety profile. In this review, we argue that an arena in which these tools could provide breakthrough benefits is traumatic brain injury (TBI). TBI is a major health problem worldwide, with the majority of cases identified as mild TBI (mTBI). MTBI is of concern because it is a modifiable risk factor for dementia. A major challenge in studying mTBI is its inherent heterogeneity across a large feature space (e.g., etiology, age of injury, sex, treatment, initial health status, etc.). Parallel lines of research in human and rodent mTBI can be collated to take advantage of the full suite of neuroscience tools, from neuroimaging (electroencephalography: EEG; functional magnetic resonance imaging: fMRI; diffusion tensor imaging: DTI) to biochemical assays. Despite these attractive components and the need for effective treatments, there are at least two major challenges to implementation. First, there is insufficient understanding of how neurostimulation alters neural mechanisms. Second, there is insufficient understanding of how mTBI alters neural function. The goal of this review is to assemble interrelated but disparate areas of research to identify important gaps in knowledge impeding the implementation of neurostimulation.
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Affiliation(s)
- M. Windy McNerney
- Mental Illness Research Education and Clinical Center (MIRECC), Veterans Affairs Palo Alto Health Care System, Palo Alto, CA 94304, USA; (M.W.M.); (C.B.)
- Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Gene G. Gurkoff
- Department of Neurological Surgery, and Center for Neuroscience, University of California, Davis, Sacramento, CA 95817, USA;
- Department of Veterans Affairs, VA Northern California Health Care System, Martinez, CA 94553, USA
| | - Charlotte Beard
- Mental Illness Research Education and Clinical Center (MIRECC), Veterans Affairs Palo Alto Health Care System, Palo Alto, CA 94304, USA; (M.W.M.); (C.B.)
- Program in Neuroscience and Behavioral Biology, Emory University, Atlanta, GA 30322, USA
| | - Marian E. Berryhill
- Programs in Cognitive and Brain Sciences, and Integrative Neuroscience, Department of Psychology, University of Nevada, Reno, NV 89557, USA
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Rong J, Yang Y, Liang M, Zhong H, Li Y, Zhu Y, Sha S, Chen L, Zhou R. Neonatal inflammation increases hippocampal KCC2 expression through methylation-mediated TGF-β1 downregulation leading to impaired hippocampal cognitive function and synaptic plasticity in adult mice. J Neuroinflammation 2023; 20:15. [PMID: 36691035 PMCID: PMC9872321 DOI: 10.1186/s12974-023-02697-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Accepted: 01/12/2023] [Indexed: 01/25/2023] Open
Abstract
The mechanisms by which neonatal inflammation leads to cognitive deficits in adulthood remain poorly understood. Inhibitory GABAergic synaptic transmission plays a vital role in controlling learning, memory and synaptic plasticity. Since early-life inflammation has been reported to adversely affect the GABAergic synaptic transmission, the aim of this study was to investigate whether and how neonatal inflammation affects GABAergic synaptic transmission resulting in cognitive impairment. Neonatal mice received a daily subcutaneous injection of lipopolysaccharide (LPS, 50 μg/kg) or saline on postnatal days 3-5. It was found that blocking GABAergic synaptic transmission reversed the deficit in hippocampus-dependent memory or the induction failure of long-term potentiation in the dorsal CA1 in adult LPS mice. An increase of mIPSCs amplitude was further detected in adult LPS mice indicative of postsynaptic potentiation of GABAergic transmission. Additionally, neonatal LPS resulted in the increased expression and function of K+-Cl--cotransporter 2 (KCC2) and the decreased expression of transforming growth factor-beta 1 (TGF-β1) in the dorsal CA1 during adulthood. The local TGF-β1 overexpression improved KCC2 expression and function, synaptic plasticity and memory of adult LPS mice. Adult LPS mice show hypermethylation of TGFb1 promoter and negatively correlate with reduced TGF-β1 transcripts. 5-Aza-deoxycytidine restored the changes in TGFb1 promoter methylation and TGF-β1 expression. Altogether, the results suggest that hypermethylation-induced reduction of TGF-β1 leads to enhanced GABAergic synaptic inhibition through increased KCC2 expression, which is a underlying mechanism of neonatal inflammation-induced hippocampus-dependent memory impairment in adult mice.
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Affiliation(s)
- Jing Rong
- grid.89957.3a0000 0000 9255 8984Department of Physiology, Nanjing Medical University, Longmian Avenue 101, Jiangning District, Nanjing, 211166 Jiangsu China
| | - Yang Yang
- grid.89957.3a0000 0000 9255 8984Department of Physiology, Nanjing Medical University, Longmian Avenue 101, Jiangning District, Nanjing, 211166 Jiangsu China
| | - Min Liang
- grid.89957.3a0000 0000 9255 8984Department of Physiology, Nanjing Medical University, Longmian Avenue 101, Jiangning District, Nanjing, 211166 Jiangsu China
| | - Haiquan Zhong
- grid.89957.3a0000 0000 9255 8984Department of Physiology, Nanjing Medical University, Longmian Avenue 101, Jiangning District, Nanjing, 211166 Jiangsu China
| | - Yingchun Li
- grid.89957.3a0000 0000 9255 8984Department of Physiology, Nanjing Medical University, Longmian Avenue 101, Jiangning District, Nanjing, 211166 Jiangsu China
| | - Yichao Zhu
- grid.89957.3a0000 0000 9255 8984Department of Physiology, Nanjing Medical University, Longmian Avenue 101, Jiangning District, Nanjing, 211166 Jiangsu China
| | - Sha Sha
- grid.89957.3a0000 0000 9255 8984Department of Physiology, Nanjing Medical University, Longmian Avenue 101, Jiangning District, Nanjing, 211166 Jiangsu China
| | - Lei Chen
- grid.89957.3a0000 0000 9255 8984Department of Physiology, Nanjing Medical University, Longmian Avenue 101, Jiangning District, Nanjing, 211166 Jiangsu China
| | - Rong Zhou
- grid.89957.3a0000 0000 9255 8984Department of Physiology, Nanjing Medical University, Longmian Avenue 101, Jiangning District, Nanjing, 211166 Jiangsu China
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Konduru SR, Isaacson JR, Lasky DJ, Zhou Z, Rao RK, Vattem SS, Rewey SJ, Jones MV, Maganti RK. Dual orexin antagonist normalized sleep homeostatic drive, enhanced GABAergic inhibition, and suppressed seizures after traumatic brain injury. Sleep 2022; 45:zsac238. [PMID: 36165953 PMCID: PMC9742898 DOI: 10.1093/sleep/zsac238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Revised: 09/16/2022] [Indexed: 12/24/2022] Open
Abstract
STUDY OBJECTIVES Traumatic brain injury (TBI) can result in posttraumatic epilepsy (PTE) and sleep disturbances. We hypothesized that treatment with sleep aids after TBI can ameliorate PTE. METHODS CD-1 mice underwent controlled cortical impact (CCI), sham injury, or no craniotomy. Sham and CCI groups underwent a monthlong daily treatment with sleep aids including a dual orexin antagonist (DORA-22) or THIP (gaboxadol) or a respective vehicle starting on the day of CCI. We performed continuous EEG (electroencephalography) recordings at week 1 and months 1, 2, and 3 for ~1 week each time. Seizure analysis occurred at all-time points and sleep analysis occurred in week 1 and month-1/2 in all groups. Subsets of CCI and sham groups were subjected to voltageclamp experiments in hippocampal slices to evaluate GABAergic synaptic inhibition. RESULTS DORA-22 treatment suppressed seizures in month 1-3 recordings. TBI reduced the amplitude and frequency of miniature inhibitory synaptic currents (mIPSCs) in dentate granule cells and these changes were rescued by DORA-22 treatment. Sleep analysis showed that DORA-22 increased nonrapid eye movement (NREM) sleep during lights-off whereas THIP increased REM sleep during lights-on in week 1. Both treatments displayed subtle changes in time spent in NREM or REM at month-1/2 as well. TBI not only increased normalized EEG delta power (NΔ) at week-1 and month-1 but also resulted in the loss of the homeostatic diurnal oscillation of NΔ, which was restored by DORA-22 but not THIP treatment. CONCLUSIONS Dual orexin antagonists may have a therapeutic potential in suppressing PTE potentially by enhancing GABAergic inhibition and impacting sleep homeostatic drive.
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Affiliation(s)
- Sruthi R Konduru
- Department of Neurology, Wayne State University, Detroit, MI, USA
| | - Jesse R Isaacson
- Department of Neurology, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
| | - Danny J Lasky
- Department of Neuroscience, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
| | - Zihao Zhou
- Rock Bridge High School, Columbia, MO, USA
| | | | - Swati S Vattem
- Department of Neurology, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
| | - Sophie J Rewey
- Department of Neurology, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
| | - Mathew V Jones
- Department of Neuroscience, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
| | - Rama K Maganti
- Department of Neurology, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
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6
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Cai X, Qiu L, Wang C, Yang H, Zhou Z, Mao M, Zhu Y, Wen Y, Cai W, Zhu W, Sun J. Hippocampal Inhibitory Synapsis Deficits Induced by α5-Containing GABA A Receptors Mediate Chronic Neuropathic Pain-Related Cognitive Impairment. Mol Neurobiol 2022; 59:6049-6061. [PMID: 35849280 DOI: 10.1007/s12035-022-02955-8] [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: 04/14/2022] [Accepted: 07/02/2022] [Indexed: 10/17/2022]
Abstract
Chronic neuropathic pain often leads to cognitive impairment, but the exact mechanism remains unclear. Gamma-aminobutyric acid A receptors (GABAARs) are the major inhibitory receptors in the brain, of which the α5-containing GABAARs (GABAARs-α5) are implicated in a range of neuropsychiatric disorders with cognitive deficits. However, whether GABAARs-α5 are involved in chronic neuropathic pain-related cognitive impairment remains unknown. In this study, the rats with chronic neuropathic pain induced by right sciatic nerve ligation injury (SNI) exhibited cognitive impairment with declined spontaneous alternation in Y-maze test and discrimination index in novel object recognition test. The GABAARs-α5 expressing on parvalbumin and somatostatin interneurons increased remarkably in hippocampus, resulting in decreased mean frequency of spontaneous inhibitory postsynaptic currents in hippocampal pyramidal neurons. Significantly, antagonizing the GABAARs-α5 by L655708 rescued weakened inhibitory synaptic transmission and cognitive impairment induced by chronic neuropathic pain. Taken together, these data suggest that the GABAARs-α5 play a crucial role in chronic neuropathic pain-induced cognitive impairment by weakening inhibitory synaptic transmission, which may provide insights into the pharmacologic treatment of chronic neuropathic pain-related cognitive impairment.
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Affiliation(s)
- Xuechun Cai
- Department of Anesthesiology and Perioperative Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, People's Republic of China
| | - Lili Qiu
- Department of Anesthesiology, Zhongda Hospital, Medical School, Southeast University, Nanjing, Jiangsu, People's Republic of China
| | - Chaoran Wang
- Department of Anesthesiology and Perioperative Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, People's Republic of China
| | - Hang Yang
- Department of Anesthesiology and Perioperative Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, People's Republic of China
| | - Zhenhui Zhou
- Department of Anesthesiology and Perioperative Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, People's Republic of China
| | - Meng Mao
- Department of Anesthesiology, Department of Anesthesiology, The Affiliated Stomatological Hospital of Nanjing Medical University, Nanjing, Jiangsu Province, China
| | - Yunqing Zhu
- Department of Anesthesiology and Perioperative Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, People's Republic of China
| | - Yazhou Wen
- Department of Anesthesiology, Nanjing Maternity and Child Health Care Hospital, Nanjing, Jiangsu, People's Republic of China
| | - Wenlan Cai
- Department of Anesthesiology, Zhongda Hospital, Medical School, Southeast University, Nanjing, Jiangsu, People's Republic of China
| | - Wei Zhu
- Department of Anesthesiology and Perioperative Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, People's Republic of China.
| | - Jie Sun
- Department of Anesthesiology, Zhongda Hospital, Medical School, Southeast University, Nanjing, Jiangsu, People's Republic of China.
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Boychuk JA, Butler CR, Smith KC, Halmos MB, Smith BN. Zolpidem Profoundly Augments Spared Tonic GABAAR Signaling in Dentate Granule Cells Ipsilateral to Controlled Cortical Impact Brain Injury in Mice. Front Syst Neurosci 2022; 16:867323. [PMID: 35694044 PMCID: PMC9178240 DOI: 10.3389/fnsys.2022.867323] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 05/05/2022] [Indexed: 11/18/2022] Open
Abstract
Type A GABA receptors (GABAARs) are pentameric combinations of protein subunits that give rise to tonic (ITonicGABA) and phasic (i.e., synaptic; ISynapticGABA) forms of inhibitory GABAAR signaling in the central nervous system. Remodeling and regulation of GABAAR protein subunits are implicated in a wide variety of healthy and injury-dependent states, including epilepsy. The present study undertook a detailed analysis of GABAAR signaling using whole-cell patch clamp recordings from mouse dentate granule cells (DGCs) in coronal slices containing dorsal hippocampus at 1–2 or 8–13 weeks after a focal, controlled cortical impact (CCI) or sham brain injury. Zolpidem, a benzodiazepine-like positive modulator of GABAARs, was used to test for changes in GABAAR signaling of DGCs due to its selectivity for α1 subunit-containing GABAARs. Electric charge transfer and statistical percent change were analyzed in order to directly compare tonic and phasic GABAAR signaling and to account for zolpidem’s ability to modify multiple parameters of GABAAR kinetics. We observed that baseline ITonicGABA is preserved at both time-points tested in DGCs ipsilateral to injury (Ipsi-DGCs) compared to DGCs contralateral to injury (Contra-DGCs) or after sham injury (Sham-DGCs). Interestingly, application of zolpidem resulted in modulation of ITonicGABA across groups, with Ipsi-DGCs exhibiting the greatest responsiveness to zolpidem. We also report that the combination of CCI and acute application of zolpidem profoundly augments the proportion of GABAAR charge transfer mediated by tonic vs. synaptic currents at both time-points tested, whereas gene expression of GABAAR α1, α2, α3, and γ2 subunits is unchanged at 8–13 weeks post-injury. Overall, this work highlights the shift toward elevated influence of tonic inhibition in Ipsi-DGCs, the impact of zolpidem on all components of inhibitory control of DGCs, and the sustained nature of these changes in inhibitory tone after CCI injury.
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Affiliation(s)
- Jeffery A Boychuk
- Department of Physiology, University of Kentucky, Lexington, KY, United States
- Department of Cellular and Integrative Physiology, UT Health San Antonio, San Antonio, TX, United States
| | - Corwin R Butler
- Department of Physiology, University of Kentucky, Lexington, KY, United States
- Department of Anesthesiology and Perioperative Medicine, Oregon Health and Science University, Portland, OR, United States
| | - Katalin Cs Smith
- Department of Physiology, University of Kentucky, Lexington, KY, United States
- Department of Neuroscience, University of Kentucky, Lexington, KY, United States
| | - Miklos B Halmos
- Department of Psychology, Georgia State University, Atlanta, GA, United States
| | - Bret N Smith
- Department of Physiology, University of Kentucky, Lexington, KY, United States
- Department of Neuroscience, University of Kentucky, Lexington, KY, United States
- Spinal Cord and Brain Injury Research Center (SCoBIRC), University of Kentucky, Lexington, KY, United States
- Department of Biomedical Sciences, Colorado State University, Fort Collins, CO, United States
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Golub VM, Reddy DS. Post-Traumatic Epilepsy and Comorbidities: Advanced Models, Molecular Mechanisms, Biomarkers, and Novel Therapeutic Interventions. Pharmacol Rev 2022; 74:387-438. [PMID: 35302046 PMCID: PMC8973512 DOI: 10.1124/pharmrev.121.000375] [Citation(s) in RCA: 28] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Post-traumatic epilepsy (PTE) is one of the most devastating long-term, network consequences of traumatic brain injury (TBI). There is currently no approved treatment that can prevent onset of spontaneous seizures associated with brain injury, and many cases of PTE are refractory to antiseizure medications. Post-traumatic epileptogenesis is an enduring process by which a normal brain exhibits hypersynchronous excitability after a head injury incident. Understanding the neural networks and molecular pathologies involved in epileptogenesis are key to preventing its development or modifying disease progression. In this article, we describe a critical appraisal of the current state of PTE research with an emphasis on experimental models, molecular mechanisms of post-traumatic epileptogenesis, potential biomarkers, and the burden of PTE-associated comorbidities. The goal of epilepsy research is to identify new therapeutic strategies that can prevent PTE development or interrupt the epileptogenic process and relieve associated neuropsychiatric comorbidities. Therefore, we also describe current preclinical and clinical data on the treatment of PTE sequelae. Differences in injury patterns, latency period, and biomarkers are outlined in the context of animal model validation, pathophysiology, seizure frequency, and behavior. Improving TBI recovery and preventing seizure onset are complex and challenging tasks; however, much progress has been made within this decade demonstrating disease modifying, anti-inflammatory, and neuroprotective strategies, suggesting this goal is pragmatic. Our understanding of PTE is continuously evolving, and improved preclinical models allow for accelerated testing of critically needed novel therapeutic interventions in military and civilian persons at high risk for PTE and its devastating comorbidities.
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Affiliation(s)
- Victoria M Golub
- Department of Neuroscience and Experimental Therapeutics, College of Medicine, Texas A&M University Health Science Center, Bryan, Texas
| | - Doodipala Samba Reddy
- Department of Neuroscience and Experimental Therapeutics, College of Medicine, Texas A&M University Health Science Center, Bryan, Texas
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Faillot M, Chaillet A, Palfi S, Senova S. Rodent models used in preclinical studies of deep brain stimulation to rescue memory deficits. Neurosci Biobehav Rev 2021; 130:410-432. [PMID: 34437937 DOI: 10.1016/j.neubiorev.2021.08.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 08/10/2021] [Accepted: 08/13/2021] [Indexed: 11/28/2022]
Abstract
Deep brain stimulation paradigms might be used to treat memory disorders in patients with stroke or traumatic brain injury. However, proof of concept studies in animal models are needed before clinical translation. We propose here a comprehensive review of rodent models for Traumatic Brain Injury and Stroke. We systematically review the histological, behavioral and electrophysiological features of each model and identify those that are the most relevant for translational research.
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Affiliation(s)
- Matthieu Faillot
- Neurosurgery department, Henri Mondor University Hospital, APHP, DMU CARE, Université Paris Est Créteil, Mondor Institute for Biomedical Research, INSERM U955, Team 15, Translational Neuropsychiatry, France
| | - Antoine Chaillet
- Laboratoire des Signaux et Systèmes (L2S-UMR8506) - CentraleSupélec, Université Paris Saclay, Institut Universitaire de France, France
| | - Stéphane Palfi
- Neurosurgery department, Henri Mondor University Hospital, APHP, DMU CARE, Université Paris Est Créteil, Mondor Institute for Biomedical Research, INSERM U955, Team 15, Translational Neuropsychiatry, France
| | - Suhan Senova
- Neurosurgery department, Henri Mondor University Hospital, APHP, DMU CARE, Université Paris Est Créteil, Mondor Institute for Biomedical Research, INSERM U955, Team 15, Translational Neuropsychiatry, France.
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10
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Traumatic Brain Injury Broadly Affects GABAergic Signaling in Dentate Gyrus Granule Cells. eNeuro 2021; 8:ENEURO.0055-20.2021. [PMID: 33514602 PMCID: PMC8116114 DOI: 10.1523/eneuro.0055-20.2021] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Revised: 01/08/2021] [Accepted: 01/12/2021] [Indexed: 02/02/2023] Open
Abstract
Traumatic brain injury (TBI) causes cellular and molecular alterations that contribute to neuropsychiatric disease and epilepsy. GABAergic dysfunction figures prominently in the pathophysiology of TBI, yet the effects of TBI on tonic inhibition in hippocampus remain uncertain. We used a mouse model of severe TBI [controlled cortical impact (CCI)] to investigate GABAergic signaling in dentate gyrus granule cells (DGGCs). Basal tonic GABA currents were not affected by CCI. However, tonic currents induced by the δ subunit-selective GABAA receptor agonist 4,5,6,7-tetrahydroisoxazolo[5,4-c]pyridin-3-ol (THIP; 10 μm) were reduced by 44% in DGGCs ipsilateral to CCI (CCI-ipsi), but not in contralateral DGGCs. Reduced THIP currents were apparent one week after injury and persisted up to 15 weeks. The frequency of spontaneous IPSCs (sIPSCs) was reduced in CCI-ipsi cells, but the amplitude and kinetics of sIPSCs were unaffected. Immunohistochemical analysis showed reduced expression of GABAA receptor δ subunits and GABAB receptor B2 subunits after CCI, by 43% and 40%, respectively. Activation of postsynaptic GABAB receptors caused a twofold increase in tonic currents, and this effect was markedly attenuated in CCI-ipsi cells (92% reduction). GABAB receptor-activated K+ currents in DGGCs were also significantly reduced in CCI-ipsi cells, confirming a functional deficit of GABAB receptors after CCI. Results indicate broad disruption of GABAergic signaling in DGGCs after CCI, with deficits in both phasic and tonic inhibition and GABAB receptor function. These changes are predicted to disrupt operation of hippocampal networks and contribute to sequelae of severe TBI, including epilepsy.
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11
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Traumatic Brain Injury Diminishes Feedforward Activation of Parvalbumin-Expressing Interneurons in the Dentate Gyrus. eNeuro 2020; 7:ENEURO.0195-19.2020. [PMID: 33106385 PMCID: PMC7675145 DOI: 10.1523/eneuro.0195-19.2020] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Revised: 09/14/2020] [Accepted: 09/20/2020] [Indexed: 12/18/2022] Open
Abstract
Traumatic brain injury (TBI) is associated with aberrant network hyperexcitability in the dentate gyrus (DG). GABAAergic parvalbumin-expressing interneurons (PV-INs) in the DG regulate network excitability with strong, perisomatic inhibition, although the posttraumatic effects on PV-IN function after TBI are not well understood. In this study, we investigated physiological alterations in PV-INs one week after mild lateral fluid percussion injury (LFPI) in mice. PV-IN cell loss was observed in the dentate hilus after LFPI, with surviving PV-INs showing no change in intrinsic membrane properties. Whole-cell voltage clamp recordings in PV-INs revealed alterations in both EPSCs and IPSCs (EPSCs/IPSCs). Evoked EPSCs (eEPSCs) in PV-INs from perforant path electrical stimulation were diminished after injury but could be recovered with application of a GABAA-receptor antagonist. Furthermore, current-clamp recordings using minimal perforant path stimulation demonstrated a decrease in evoked PV-IN action potentials (APs) after LFPI, which could be restored by blocking GABAAergic inhibition. Together, these findings suggest that injury alters synaptic input onto PV-INs, resulting in a net inhibitory effect that reduces feedforward PV-IN activation in the DG. Decreased PV-IN activation suggests a potential mechanism of DG network hyperexcitability contributing to hippocampal dysfunction after TBI.
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12
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Probst J, Kölker S, Okun JG, Kumar A, Gursky E, Posset R, Hoffmann GF, Peravali R, Zielonka M. Chronic hyperammonemia causes a hypoglutamatergic and hyperGABAergic metabolic state associated with neurobehavioral abnormalities in zebrafish larvae. Exp Neurol 2020; 331:113330. [PMID: 32339612 DOI: 10.1016/j.expneurol.2020.113330] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 03/29/2020] [Accepted: 04/23/2020] [Indexed: 12/13/2022]
Abstract
Chronic hyperammonemia is a common condition affecting individuals with inherited urea cycle disorders resulting in progressive cognitive impairment and behavioral abnormalities. Altered neurotransmission has been proposed as major source of neuronal dysfunction during chronic hyperammonemia, but the molecular pathomechanism has remained incompletely understood. Here we show that chronic exposure to ammonium acetate induces locomotor dysfunction and abnormal feeding behavior in zebrafish larvae, indicative for an impairment of higher brain functions. Biochemically, chronically elevated ammonium concentrations cause enhanced activity of glutamate decarboxylase isoforms GAD1 and GAD2 with increased formation of GABA and concomitant depletion of glutamate, ultimately leading to a dysfunctional hypoglutamatergic and hyperGABAergic metabolic state. Moreover, elevated GABA concentrations are accompanied by increased expression of GABAA receptor subunits alpha-1, gamma-2 and delta, supporting the notion of an increased GABA tone in chronic hyperammonemia. Propionate oxidation as major anaplerotic reaction sufficiently compensates for the transamination-dependent withdrawal of 2-oxoglutarate, thereby preventing bioenergetic dysfunction under chronic hyperammonemic conditions. Thus, our study extends the hypothesis of alterations in the glutamatergic and GABAergic system being an important pathophysiological factor causing neurobehavioral impairment in chronic hyperammonemia. Given that zebrafish larvae have already been successfully used for high-throughput identification of novel compounds to treat inherited neurological diseases, the reported zebrafish model should be considered an important tool for systematic drug screening targeting altered glutamatergic and GABAergic metabolism under chronic hyperammonemic conditions in the future.
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Affiliation(s)
- Joris Probst
- Center for Child and Adolescent Medicine, Division of Pediatric Neurology and Metabolic Medicine, University Hospital Heidelberg, Heidelberg, Germany
| | - Stefan Kölker
- Center for Child and Adolescent Medicine, Division of Pediatric Neurology and Metabolic Medicine, University Hospital Heidelberg, Heidelberg, Germany
| | - Jürgen G Okun
- Center for Child and Adolescent Medicine, Division of Pediatric Neurology and Metabolic Medicine, University Hospital Heidelberg, Heidelberg, Germany
| | - Amrish Kumar
- Institute of Toxicology and Genetics (ITG), Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
| | - Eduard Gursky
- Institute of Toxicology and Genetics (ITG), Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
| | - Roland Posset
- Center for Child and Adolescent Medicine, Division of Pediatric Neurology and Metabolic Medicine, University Hospital Heidelberg, Heidelberg, Germany
| | - Georg F Hoffmann
- Center for Child and Adolescent Medicine, Division of Pediatric Neurology and Metabolic Medicine, University Hospital Heidelberg, Heidelberg, Germany
| | - Ravindra Peravali
- Institute of Toxicology and Genetics (ITG), Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
| | - Matthias Zielonka
- Center for Child and Adolescent Medicine, Division of Pediatric Neurology and Metabolic Medicine, University Hospital Heidelberg, Heidelberg, Germany; Heidelberg Research Center for Molecular Medicine (HRCMM), Heidelberg, Germany.
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13
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Bugay V, Bozdemir E, Vigil FA, Chun SH, Holstein DM, Elliott WR, Sprague CJ, Cavazos JE, Zamora DO, Rule G, Shapiro MS, Lechleiter JD, Brenner R. A Mouse Model of Repetitive Blast Traumatic Brain Injury Reveals Post-Trauma Seizures and Increased Neuronal Excitability. J Neurotrauma 2019; 37:248-261. [PMID: 31025597 DOI: 10.1089/neu.2018.6333] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Repetitive blast traumatic brain injury (TBI) affects numerous soldiers on the battlefield. Mild TBI has been shown to have long-lasting effects with repeated injury. We have investigated effects on neuronal excitability after repetitive, mild TBI in a mouse model of blast-induced brain injury. We exposed mice to mild blast trauma of an average peak overpressure of 14.6 psi, repeated across three consecutive days. While a single exposure did not reveal trauma as indicated by the glial fibrillary acidic protein indicator, three repetitive blasts did show significant increases. As well, mice had an increased indicator of inflammation (Iba-1) and increased tau, tau phosphorylation, and altered cytokine levels in the spleen. Video-electroencephalographic monitoring 48 h after the final blast exposure demonstrated seizures in 50% (12/24) of the mice, most of which were non-convulsive seizures. Long-term monitoring revealed that spontaneous seizures developed in at least 46% (6/13) of the mice. Patch clamp recording of dentate gyrus hippocampus neurons 48 h post-blast TBI demonstrated a shortened latency to the first spike and hyperpolarization of action potential threshold. We also found that evoked excitatory postsynaptic current amplitudes were significantly increased. These findings indicate that mild, repetitive blast exposures cause increases in neuronal excitability and seizures and eventual epilepsy development in some animals. The non-convulsive nature of the seizures suggests that subclinical seizures may occur in individuals experiencing even mild blast events, if repeated.
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Affiliation(s)
- Vladislav Bugay
- Cell and Integrative Physiology, University of Texas Health San Antonio, San Antonio, Texas
| | - Eda Bozdemir
- Department of Cell Systems and Anatomy, University of Texas Health San Antonio, San Antonio, Texas
| | - Fabio A Vigil
- Cell and Integrative Physiology, University of Texas Health San Antonio, San Antonio, Texas
| | - Sang H Chun
- Department of Cell Systems and Anatomy, University of Texas Health San Antonio, San Antonio, Texas
| | - Deborah M Holstein
- Department of Cell Systems and Anatomy, University of Texas Health San Antonio, San Antonio, Texas
| | - William R Elliott
- Sensory Trauma, United States Army Institute of Surgical Research, Fort Sam Houston San Antonio, Texas
| | - Cassie J Sprague
- Sensory Trauma, United States Army Institute of Surgical Research, Fort Sam Houston San Antonio, Texas
| | - Jose E Cavazos
- Cell and Integrative Physiology, University of Texas Health San Antonio, San Antonio, Texas.,Department of Neurology, University of Texas Health San Antonio, San Antonio, Texas
| | - David O Zamora
- Sensory Trauma, United States Army Institute of Surgical Research, Fort Sam Houston San Antonio, Texas
| | | | - Mark S Shapiro
- Cell and Integrative Physiology, University of Texas Health San Antonio, San Antonio, Texas
| | - James D Lechleiter
- Department of Cell Systems and Anatomy, University of Texas Health San Antonio, San Antonio, Texas
| | - Robert Brenner
- Cell and Integrative Physiology, University of Texas Health San Antonio, San Antonio, Texas
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14
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McGuire JL, Ngwenya LB, McCullumsmith RE. Neurotransmitter changes after traumatic brain injury: an update for new treatment strategies. Mol Psychiatry 2019; 24:995-1012. [PMID: 30214042 DOI: 10.1038/s41380-018-0239-6] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2017] [Revised: 08/15/2018] [Accepted: 08/20/2018] [Indexed: 12/12/2022]
Abstract
Traumatic brain injury (TBI) is a pervasive problem in the United States and worldwide, as the number of diagnosed individuals is increasing yearly and there are no efficacious therapeutic interventions. A large number of patients suffer with cognitive disabilities and psychiatric conditions after TBI, especially anxiety and depression. The constellation of post-injury cognitive and behavioral symptoms suggest permanent effects of injury on neurotransmission. Guided in part by preclinical studies, clinical trials have focused on high-yield pathophysiologic mechanisms, including protein aggregation, inflammation, metabolic disruption, cell generation, physiology, and alterations in neurotransmitter signaling. Despite successful treatment of experimental TBI in animal models, clinical studies based on these findings have failed to translate to humans. The current international effort to reshape TBI research is focusing on redefining the taxonomy and characterization of TBI. In addition, as the next round of clinical trials is pending, there is a pressing need to consider what the field has learned over the past two decades of research, and how we can best capitalize on this knowledge to inform the hypotheses for future innovations. Thus, it is critically important to extend our understanding of the pathophysiology of TBI, particularly to mechanisms that are associated with recovery versus development of chronic symptoms. In this review, we focus on the pathology of neurotransmission after TBI, reflecting on what has been learned from both the preclinical and clinical studies, and we discuss new directions and opportunities for future work.
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Affiliation(s)
- Jennifer L McGuire
- Department of Neurosurgery, University of Cincinnati, Cincinnati, OH, USA.
| | - Laura B Ngwenya
- Department of Neurosurgery, University of Cincinnati, Cincinnati, OH, USA.,Department of Neurology and Rehabilitation Medicine, University of Cincinnati, Cincinnati, OH, USA.,Neurotrauma Center, University of Cincinnati Gardner Neuroscience Institute, Cincinnati, OH, 45219, USA
| | - Robert E McCullumsmith
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati, Cincinnati, OH, USA.,Department of Psychiatry, Cincinnati Veterans Administration Medical Center, Cincinnati, OH, USA
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15
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Griffiths BB, Sahbaie P, Rao A, Arvola O, Xu L, Liang D, Ouyang Y, Clark DJ, Giffard RG, Stary CM. Pre-treatment with microRNA-181a Antagomir Prevents Loss of Parvalbumin Expression and Preserves Novel Object Recognition Following Mild Traumatic Brain Injury. Neuromolecular Med 2019; 21:170-181. [PMID: 30900118 PMCID: PMC7213504 DOI: 10.1007/s12017-019-08532-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Accepted: 03/12/2019] [Indexed: 01/04/2023]
Abstract
Mild traumatic brain injury (mTBI) can result in permanent impairment in memory and learning and may be a precursor to other neurological sequelae. Clinical treatments to ameliorate the effects of mTBI are lacking. Inhibition of microRNA-181a (miR-181a) is protective in several models of cerebral injury, but its role in mTBI has not been investigated. In the present study, miR-181a-5p antagomir was injected intracerebroventricularly 24 h prior to closed-skull cortical impact in young adult male mice. Paw withdrawal, open field, zero maze, Y maze, object location and novel object recognition tests were performed to assess neurocognitive dysfunction. Brains were assessed immunohistologically for the neuronal marker NeuN, the perineuronal net marker wisteria floribunda lectin (WFA), cFos, and the interneuron marker parvalbumin. Protein quantification was performed with immunoblots for synaptophysin and postsynaptic density 95 (PSD95). Fluorescent in situ hybridization was utilized to localize hippocampal miR-181a expression. MiR-181a antagomir treatment reduced neuronal miR-181a expression after mTBI, restored deficits in novel object recognition and increased hippocampal parvalbumin expression in the dentate gyrus. These changes were associated with decreased dentate gyrus hyperactivity indicated by a relative reduction in PSD95 and cFos expression. These results suggest that miR-181a inhibition may be a therapeutic approach to reduce hippocampal excitotoxicity and prevent cognitive dysfunction following mTBI.
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Affiliation(s)
- Brian B Griffiths
- Dept of Anesthesiology, Perioperative & Pain Medicine, Stanford University School of Medicine, 300 Pasteur Drive, Stanford, CA, 94305-5117, USA.
| | - Peyman Sahbaie
- Dept of Anesthesiology, Perioperative & Pain Medicine, Stanford University School of Medicine, 300 Pasteur Drive, Stanford, CA, 94305-5117, USA
- Department of Anesthesiology, Veterans Affairs Palo Alto Health Care System, Palo Alto, CA, USA
| | - Anand Rao
- Dept of Anesthesiology, Perioperative & Pain Medicine, Stanford University School of Medicine, 300 Pasteur Drive, Stanford, CA, 94305-5117, USA
| | - Oiva Arvola
- Dept of Anesthesiology, Perioperative & Pain Medicine, Stanford University School of Medicine, 300 Pasteur Drive, Stanford, CA, 94305-5117, USA
| | - Lijun Xu
- Dept of Anesthesiology, Perioperative & Pain Medicine, Stanford University School of Medicine, 300 Pasteur Drive, Stanford, CA, 94305-5117, USA
| | - Deyong Liang
- Dept of Anesthesiology, Perioperative & Pain Medicine, Stanford University School of Medicine, 300 Pasteur Drive, Stanford, CA, 94305-5117, USA
- Department of Anesthesiology, Veterans Affairs Palo Alto Health Care System, Palo Alto, CA, USA
| | - Yibing Ouyang
- Dept of Anesthesiology, Perioperative & Pain Medicine, Stanford University School of Medicine, 300 Pasteur Drive, Stanford, CA, 94305-5117, USA
| | - David J Clark
- Dept of Anesthesiology, Perioperative & Pain Medicine, Stanford University School of Medicine, 300 Pasteur Drive, Stanford, CA, 94305-5117, USA
- Department of Anesthesiology, Veterans Affairs Palo Alto Health Care System, Palo Alto, CA, USA
| | - Rona G Giffard
- Dept of Anesthesiology, Perioperative & Pain Medicine, Stanford University School of Medicine, 300 Pasteur Drive, Stanford, CA, 94305-5117, USA
| | - Creed M Stary
- Dept of Anesthesiology, Perioperative & Pain Medicine, Stanford University School of Medicine, 300 Pasteur Drive, Stanford, CA, 94305-5117, USA.
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16
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Keating N, Zeak N, Smith SS. Pubertal hormones increase hippocampal expression of α4βδ GABA A receptors. Neurosci Lett 2019; 701:65-70. [PMID: 30742936 DOI: 10.1016/j.neulet.2019.02.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Revised: 02/03/2019] [Accepted: 02/04/2019] [Indexed: 12/13/2022]
Abstract
CA1 hippocampal expression of α4βδ GABAA receptors (GABARs) increases at the onset of puberty in female mice, an effect dependent upon the decline in hippocampal levels of the neurosteroid THP (3α-OH-5α-pregnan-20-one) which occurs at this time. The present study further characterized the mechanisms underlying α4βδ expression, assessed in vivo. Blockade of pubertal levels of 17β-estradiol (E2) (formestane, 0.5 mg/kg, i.p. 3 d) reduced α4 and δ expression by 75-80% (P < 0.05) in CA1 hippocampus of female mice, assessed using Western blot techniques. Conversely, E2 administration increased α4 and δ expression by 50-100% in adults, an effect enhanced by more than 2-fold by concomitant administration of the 5α-reductase blocker finasteride (50 mg/kg, i.p., 3d, P < 0.05), suggesting that both declining THP levels and increasing E2 levels before puberty trigger α4βδ expression. This effect was blocked by ICI 182,780 (20 mg/kg, s.c., 3 d), a selective blocker of E2 receptor-α (ER-α). These results suggest that both the rise in circulating levels of E2 and the decline in hippocampal THP levels at the onset of puberty trigger maximal levels of α4βδ expression in the CA1 hippocampus.
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Affiliation(s)
- Nicole Keating
- Department of Physiology and Pharmacology, SUNY Downstate Medical Center, 450 Clarkson Ave., Brooklyn, NY, 11203, USA
| | - Nicole Zeak
- Department of Physiology and Pharmacology, SUNY Downstate Medical Center, 450 Clarkson Ave., Brooklyn, NY, 11203, USA
| | - Sheryl S Smith
- Department of Physiology and Pharmacology, SUNY Downstate Medical Center, 450 Clarkson Ave., Brooklyn, NY, 11203, USA.
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17
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Joshi S, Kapur J. Neurosteroid regulation of GABA A receptors: A role in catamenial epilepsy. Brain Res 2019; 1703:31-40. [PMID: 29481795 PMCID: PMC6107446 DOI: 10.1016/j.brainres.2018.02.031] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Revised: 09/08/2017] [Accepted: 02/20/2018] [Indexed: 12/31/2022]
Abstract
The female reproductive hormones progesterone and estrogen regulate network excitability. Fluctuations in the circulating levels of these hormones during the menstrual cycle cause frequent seizures during certain phases of the cycle in women with epilepsy. This seizure exacerbation, called catamenial epilepsy, is a dominant form of drug-refractory epilepsy in women of reproductive age. Progesterone, through its neurosteroid derivative allopregnanolone, increases γ-aminobutyric acid type-A receptor (GABAR)-mediated inhibition in the brain and keeps seizures under control. Catamenial seizures are believed to be a neurosteroid withdrawal symptom, and it was hypothesized that exogenous administration of progesterone to maintain its levels high during luteal phase will treat catamenial seizures. However, in a multicenter, double-blind, phase III clinical trial, progesterone treatment did not suppress catamenial seizures. The expression of GABARs with reduced neurosteroid sensitivity in epileptic animals may explain the failure of the progesterone clinical trial. The expression of neurosteroid-sensitive δ subunit-containing GABARs is reduced, and the expression of α4γ2 subunit-containing GABARs is upregulated, which alters the inhibition of dentate granule cells in epilepsy. These changes reduce the endogenous neurosteroid control of seizures and contribute to catamenial seizures.
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Affiliation(s)
- Suchitra Joshi
- Department of Neurology, University of Virginia, Charlottesville, VA 22908, United States.
| | - Jaideep Kapur
- Department of Neurology, University of Virginia, Charlottesville, VA 22908, United States; Department of Neuroscience, University of Virginia, Charlottesville, VA 22908, United States
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18
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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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19
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Khozhai LI, Otellin VA. Distribution of GAD67-expressing neurons and morphological changes in hippocampal structures during pubertal period after acute perinatal hypoxia in rats. J EVOL BIOCHEM PHYS+ 2018. [DOI: 10.1134/s0022093017060084] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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20
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Cheng JP, Leary JB, O'Neil DA, Meyer EA, Free KE, Bondi CO, Kline AE. Spontaneous recovery of traumatic brain injury-induced functional deficits is not hindered by daily administration of lorazepam. Behav Brain Res 2017; 339:215-221. [PMID: 29203336 DOI: 10.1016/j.bbr.2017.11.039] [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: 08/29/2017] [Revised: 11/02/2017] [Accepted: 11/30/2017] [Indexed: 10/18/2022]
Abstract
Agitation and aggression are common sequelae of traumatic brain injury (TBI) and pose a challenge to physicians and other health providers during acute patient care and subsequent neurorehabilitation. Antipsychotic drugs (APDs) are routinely administered to manage TBI patients displaying such maladaptive behaviors despite several clinical and preclinical studies demonstrating that they hinder recovery. A potentially viable alternative to APDs may be the benzodiazepines, which have differing mechanisms of action. Hence, the aim of the study was to test the hypothesis that lorazepam (LOR) would not impede recovery after TBI. Anesthetized adult male rats received a cortical impact or sham injury and then were intraperitoneally administered LOR (0.1mg/kg, 1.0mg/kg, or 2.0mg/kg) or vehicle (VEH; 1mL/kg) commencing 24-h after surgery and once daily for 19days. Motor and cognitive outcomes were assessed on post-operative days 1-5 and 14-19, respectively. No differences were revealed among the four sham control groups and thus they were pooled into one inclusive SHAM group. The SHAMs performed better than all TBI groups on all assessments (p<0.05). Regarding TBI, the 2.0mg/kg LOR group performed better than the VEH and 0.1mg/kg or 1.0mg/kg LOR groups on every task (p<0.05); no differences were observed among the latter three groups on any endpoint (p>0.05). Overall, these preclinical behavioral data support the hypothesis and reveal a therapeutic benefit with the higher dose of LOR. The findings suggest that LOR may be an alternative, to APDs, for controlling agitation without compromising spontaneous recovery and perhaps could afford a dual benefit by also promoting therapeutic efficacy.
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Affiliation(s)
- Jeffrey P Cheng
- Physical Medicine & Rehabilitation, University of Pittsburgh, Pittsburgh, PA, 15213, United States; Safar Center for Resuscitation Research, University of Pittsburgh, Pittsburgh, PA, 15213, United States
| | - Jacob B Leary
- Physical Medicine & Rehabilitation, University of Pittsburgh, Pittsburgh, PA, 15213, United States; Safar Center for Resuscitation Research, University of Pittsburgh, Pittsburgh, PA, 15213, United States
| | - Darik A O'Neil
- Physical Medicine & Rehabilitation, University of Pittsburgh, Pittsburgh, PA, 15213, United States; Safar Center for Resuscitation Research, University of Pittsburgh, Pittsburgh, PA, 15213, United States
| | - Elizabeth A Meyer
- Physical Medicine & Rehabilitation, University of Pittsburgh, Pittsburgh, PA, 15213, United States; Safar Center for Resuscitation Research, University of Pittsburgh, Pittsburgh, PA, 15213, United States
| | - Kristin E Free
- Physical Medicine & Rehabilitation, University of Pittsburgh, Pittsburgh, PA, 15213, United States; Safar Center for Resuscitation Research, University of Pittsburgh, Pittsburgh, PA, 15213, United States
| | - Corina O Bondi
- Physical Medicine & Rehabilitation, University of Pittsburgh, Pittsburgh, PA, 15213, United States; Neurobiology, University of Pittsburgh, Pittsburgh, PA, 15213, United States; Center for Neuroscience, University of Pittsburgh, Pittsburgh, PA, 15213, United States
| | - Anthony E Kline
- Physical Medicine & Rehabilitation, University of Pittsburgh, Pittsburgh, PA, 15213, United States; Safar Center for Resuscitation Research, University of Pittsburgh, Pittsburgh, PA, 15213, United States; Center for Neuroscience, University of Pittsburgh, Pittsburgh, PA, 15213, United States; Center for the Neural Basis of Cognition, University of Pittsburgh, Pittsburgh, PA, 15213, United States; Critical Care Medicine, University of Pittsburgh, Pittsburgh, PA, 15213, United States; Psychology, University of Pittsburgh, PA, 15213, United States.
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21
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Brizuela M, Blizzard CA, Chuckowree JA, Pitman KA, Young KM, Dickson T. Mild Traumatic Brain Injury Leads to Decreased Inhibition and a Differential Response of Calretinin Positive Interneurons in the Injured Cortex. J Neurotrauma 2017; 34:2504-2517. [DOI: 10.1089/neu.2017.4977] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Affiliation(s)
- Mariana Brizuela
- Menzies Institute for Medical Research, University of Tasmania, Tasmania, Australia
| | | | - Jyoti A. Chuckowree
- Menzies Institute for Medical Research, University of Tasmania, Tasmania, Australia
| | - Kimberley A. Pitman
- Menzies Institute for Medical Research, University of Tasmania, Tasmania, Australia
| | - Kaylene M. Young
- Menzies Institute for Medical Research, University of Tasmania, Tasmania, Australia
| | - Tracey Dickson
- Menzies Institute for Medical Research, University of Tasmania, Tasmania, Australia
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22
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Paterno R, Folweiler KA, Cohen AS. Pathophysiology and Treatment of Memory Dysfunction After Traumatic Brain Injury. Curr Neurol Neurosci Rep 2017; 17:52. [PMID: 28500417 PMCID: PMC5861722 DOI: 10.1007/s11910-017-0762-x] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Memory is fundamental to everyday life, and cognitive impairments resulting from traumatic brain injury (TBI) have devastating effects on TBI survivors. A contributing component to memory impairments caused by TBI is alteration in the neural circuits associated with memory function. In this review, we aim to bring together experimental findings that characterize behavioral memory deficits and the underlying pathophysiology of memory-involved circuits after TBI. While there is little doubt that TBI causes memory and cognitive dysfunction, it is difficult to conclude which memory phase, i.e., encoding, maintenance, or retrieval, is specifically altered by TBI. This is most likely due to variation in behavioral protocols and experimental models. Additionally, we review a selection of experimental treatments that hold translational potential to mitigate memory dysfunction following injury.
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Affiliation(s)
- Rosalia Paterno
- Center for Sleep and Circadian Neurobiology, Perelman School of Medicine, University of Pennsylvania, 3615 Civic Center Boulevard, Abramson Research Center, Rm. 816-h, Philadelphia, PA, 19104, USA.
| | - Kaitlin A Folweiler
- Department of Anesthesiology and Critical Care Medicine, Joseph Stokes, Jr. Research Institute, Children's Hospital of Philadelphia, 3615 Civic Center Boulevard, Abramson Research Center, Rm. 816-h, Philadelphia, PA, 19104, USA
| | - Akiva S Cohen
- Department of Anesthesiology and Critical Care Medicine, Joseph Stokes, Jr. Research Institute, Children's Hospital of Philadelphia, 3615 Civic Center Boulevard, Abramson Research Center, Rm. 816-h, Philadelphia, PA, 19104, USA
- Department of Anesthesiology and Critical Care Medicine, Perelman School of Medicine, University of Pennsylvania, 3615 Civic Center Boulevard, Abramson Research Center, Rm. 816-h, Philadelphia, PA, 19104, USA
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23
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Simonsen C, Boddum K, von Schoubye NL, Kloppenburg A, Sønderskov K, Hansen SL, Kristiansen U. Anticonvulsive evaluation of THIP in the murine pentylenetetrazole kindling model: lack of anticonvulsive effect of THIP despite functional δ-subunit-containing GABA A receptors in dentate gyrus granule cells. Pharmacol Res Perspect 2017; 5. [PMID: 28805971 PMCID: PMC5684853 DOI: 10.1002/prp2.322] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Revised: 04/20/2017] [Accepted: 04/21/2017] [Indexed: 12/29/2022] Open
Abstract
THIP (4,5,6,7‐tetrahydroisoxazolo[5,4‐c]pyridin‐3‐ol) is a GABAA receptor agonist with varying potencies and efficacies at γ‐subunit‐containing receptors. More importantly, THIP acts as a selective superagonist at δ‐subunit‐containing receptors (δ‐GABAARs) at clinically relevant concentrations. Evaluation of THIP as a potential anticonvulsant has given contradictory results in different animal models and for this reason, we reevaluated the anticonvulsive properties of THIP in the murine pentylenetetrazole (PTZ) kindling model. As loss of δ‐GABAAR in the dentate gyrus has been associated with several animal models of epilepsy, we first investigated the presence of functional δ‐GABAA receptors. Both immunohistochemistry and Western blot data demonstrated that δ‐GABAAR expression is not only present in the dentate gyrus, but also the expression level was enhanced in the early phase after PTZ kindling. Whole‐cell patch‐clamp studies in acute hippocampal brain slices revealed that THIP was indeed able to induce a tonic inhibition in dentate gyrus granule cells. However, THIP induced a tonic current of similar magnitude in the PTZ‐kindled mice compared to saline‐treated animals despite the observed upregulation of δ‐GABAARs. Even in the demonstrated presence of functional δ‐GABAARs, THIP (0.5–4 mg/kg) showed no anticonvulsive effect in the PTZ kindling model using a comprehensive in vivo evaluation of the anticonvulsive properties.
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Affiliation(s)
- Charlotte Simonsen
- Faculty of Health and Medical Sciences, Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Kim Boddum
- Faculty of Health and Medical Sciences, Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark.,Faculty of Health and Medical Sciences, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Nadia L von Schoubye
- Faculty of Health and Medical Sciences, Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark.,Faculty of Health and Medical Sciences, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Alissa Kloppenburg
- Faculty of Health and Medical Sciences, Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Kasper Sønderskov
- Faculty of Health and Medical Sciences, Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Suzanne L Hansen
- Faculty of Health and Medical Sciences, Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Uffe Kristiansen
- Faculty of Health and Medical Sciences, Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
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24
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Abstract
Every year in the United States, millions of individuals incur ischemic brain injury from stroke, cardiac arrest, or traumatic brain injury. These acquired brain injuries can lead to death or long-term neurologic and neuropsychological impairments. The mechanisms of ischemic and traumatic brain injury that lead to these deficiencies result from a complex interplay of interdependent molecular pathways, including excitotoxicity, acidotoxicity, ionic imbalance, oxidative stress, inflammation, and apoptosis. This article reviews several mechanisms of brain injury and discusses recent developments. Although much is known from animal models of injury, it has been difficult to translate these effects to humans.
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Affiliation(s)
- Nidia Quillinan
- Department of Anesthesiology, University of Colorado Denver, Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Paco S Herson
- Department of Anesthesiology, University of Colorado Denver, Anschutz Medical Campus, Aurora, CO 80045, USA; Department of Pharmacology, University of Colorado Denver, Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Richard J Traystman
- Department of Anesthesiology, University of Colorado Denver, Anschutz Medical Campus, Aurora, CO 80045, USA; Department of Pharmacology, University of Colorado Denver, Anschutz Medical Campus, Aurora, CO 80045, USA; Department of Emergency Medicine, University of Colorado Denver, Anschutz Medical Campus, Aurora, CO 80045, USA; Department of Neurology, University of Colorado Denver, Anschutz Medical Campus, Aurora, CO 80045, USA.
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25
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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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26
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Van Horn JD, Bhattrai A, Irimia A. Multimodal Imaging of Neurometabolic Pathology due to Traumatic Brain Injury. Trends Neurosci 2016; 40:39-59. [PMID: 27939821 DOI: 10.1016/j.tins.2016.10.007] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2016] [Revised: 10/21/2016] [Accepted: 10/25/2016] [Indexed: 12/28/2022]
Abstract
The impact of traumatic brain injury (TBI) involves a combination of complex biochemical processes beginning with the initial insult and lasting for days, months and even years post-trauma. These changes range from neuronal integrity losses to neurotransmitter imbalance and metabolite dysregulation, leading to the release of pro- or anti-apoptotic factors which mediate cell survival or death. Such dynamic processes affecting the brain's neurochemistry can be monitored using a variety of neuroimaging techniques, whose combined use can be particularly useful for understanding patient-specific clinical trajectories. Here, we describe how TBI changes the metabolism of essential neurochemical compounds, summarize how neuroimaging approaches facilitate the study of such alterations, and highlight promising ways in which neuroimaging can be used to investigate post-TBI changes in neurometabolism.
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Affiliation(s)
- John Darrell Van Horn
- USC Mark and Mary Stevens Neuroimaging and Informatics Institute, 2025 Zonal Avenue, Keck School of Medicine of USC, University of Southern California, Los Angeles, California 90033, USA.
| | - Avnish Bhattrai
- USC Mark and Mary Stevens Neuroimaging and Informatics Institute, 2025 Zonal Avenue, Keck School of Medicine of USC, University of Southern California, Los Angeles, California 90033, USA
| | - Andrei Irimia
- USC Mark and Mary Stevens Neuroimaging and Informatics Institute, 2025 Zonal Avenue, Keck School of Medicine of USC, University of Southern California, Los Angeles, California 90033, USA
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27
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Chandran R, Sharma A, Bhomia M, Balakathiresan NS, Knollmann-Ritschel BE, Maheshwari RK. Differential expression of microRNAs in the brains of mice subjected to increasing grade of mild traumatic brain injury. Brain Inj 2016; 31:106-119. [PMID: 27819514 DOI: 10.1080/02699052.2016.1213420] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
OBJECTIVE To investigate the effect of heterogeneity in mTBI on miRNA expression in mouse brain and to identify molecular pathways targeted by the modulated miRNAs. METHODS A weight drop device was used to induce four increasing grades of mTBI. MiRNA expression was evaluated using TaqMan rodent miRNA arrays. Bioinformatics analysis was done using the DIANA miRPath tool and Ingenuity Pathway Analysis software. Histology of brain sections was evaluated using H&E staining. RESULTS No histologic lesions were observed in the brains of injured mice; however, significant modulation in miRNA expression profile was observed. Global miRNA profiling indicated a trend of decrease in the number of modulated miRNAs from 24 hours to day 7 post-injury, except for the most severe grade of mTBI. Canonical pathways like calcium signalling, synaptic pathways and axon guidance pathway were the major targets of the modulated miRNAs. Network correlation analyses indicated an interaction between the modulated miRNAs and putative protein biomarkers of TBI. CONCLUSIONS The data demonstrated that varying intensities of mTBI induced a differential miRNA expression profile in the brain post-injury. Pathways such as calcium and synaptic signalling were major targets of modulated miRNAs and may play a role in the pathophysiology of mTBI.
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Affiliation(s)
- Raghavendar Chandran
- a Department of Pathology , Uniformed Services University of the Health Sciences , Bethesda , MD , USA.,b Biological Sciences Group , Birla Institute of Technology and Science , Pilani , Rajasthan , India
| | - Anuj Sharma
- a Department of Pathology , Uniformed Services University of the Health Sciences , Bethesda , MD , USA
| | - Manish Bhomia
- a Department of Pathology , Uniformed Services University of the Health Sciences , Bethesda , MD , USA
| | - Nagaraja S Balakathiresan
- a Department of Pathology , Uniformed Services University of the Health Sciences , Bethesda , MD , USA
| | | | - Radha K Maheshwari
- a Department of Pathology , Uniformed Services University of the Health Sciences , Bethesda , MD , USA
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28
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Abstract
Traumatic brain injury (TBI) greatly increases the risk of medically intractable epilepsy. Several models of TBI have been developed to investigate the relationship between TBI and posttraumatic epileptogenesis. Because the incident that precipitates development of epilepsy is known, studying mechanisms of epileptogenesis, identifying biomarkers to predict PTE, and developing treatments to prevent epilepsy after TBI are attainable research goals.
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29
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Alwis DS, Yan EB, Johnstone V, Carron S, Hellewell S, Morganti-Kossmann MC, Rajan R. Environmental Enrichment Attenuates Traumatic Brain Injury: Induced Neuronal Hyperexcitability in Supragranular Layers of Sensory Cortex. J Neurotrauma 2016; 33:1084-101. [DOI: 10.1089/neu.2014.3774] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Affiliation(s)
- Dasuni Sathsara Alwis
- Department of Physiology, Monash University, Clayton, VIC, Australia
- National Trauma Research Institute, Alfred Hospital, Prahran, VIC, Australia
| | - Edwin Bingbing Yan
- National Trauma Research Institute, Alfred Hospital, Prahran, VIC, Australia
| | | | - Simone Carron
- Department of Physiology, Monash University, Clayton, VIC, Australia
| | - Sarah Hellewell
- National Trauma Research Institute, Alfred Hospital, Prahran, VIC, Australia
| | | | - Ramesh Rajan
- Department of Physiology, Monash University, Clayton, VIC, Australia
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30
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Pevzner A, Izadi A, Lee DJ, Shahlaie K, Gurkoff GG. Making Waves in the Brain: What Are Oscillations, and Why Modulating Them Makes Sense for Brain Injury. Front Syst Neurosci 2016; 10:30. [PMID: 27092062 PMCID: PMC4823270 DOI: 10.3389/fnsys.2016.00030] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Accepted: 03/22/2016] [Indexed: 01/19/2023] Open
Abstract
Traumatic brain injury (TBI) can result in persistent cognitive, behavioral and emotional deficits. However, the vast majority of patients are not chronically hospitalized; rather they have to manage their disabilities once they are discharged to home. Promoting recovery to pre-injury level is important from a patient care as well as a societal perspective. Electrical neuromodulation is one approach that has shown promise in alleviating symptoms associated with neurological disorders such as in Parkinson’s disease (PD) and epilepsy. Consistent with this perspective, both animal and clinical studies have revealed that TBI alters physiological oscillatory rhythms. More recently several studies demonstrated that low frequency stimulation improves cognitive outcome in models of TBI. Specifically, stimulation of the septohippocampal circuit in the theta frequency entrained oscillations and improved spatial learning following TBI. In order to evaluate the potential of electrical deep brain stimulation for clinical translation we review the basic neurophysiology of oscillations, their role in cognition and how they are changed post-TBI. Furthermore, we highlight several factors for future pre-clinical and clinical studies to consider, with the hope that it will promote a hypothesis driven approach to subsequent experimental designs and ultimately successful translation to improve outcome in patients with TBI.
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Affiliation(s)
- Aleksandr Pevzner
- Department of Neurological Surgery, University of California-DavisSacramento, CA, USA; Center for Neuroscience, University of California-DavisSacramento, CA, USA
| | - Ali Izadi
- Department of Neurological Surgery, University of California-DavisSacramento, CA, USA; Center for Neuroscience, University of California-DavisSacramento, CA, USA
| | - Darrin J Lee
- Department of Neurological Surgery, University of California-DavisSacramento, CA, USA; Center for Neuroscience, University of California-DavisSacramento, CA, USA
| | - Kiarash Shahlaie
- Department of Neurological Surgery, University of California-DavisSacramento, CA, USA; Center for Neuroscience, University of California-DavisSacramento, CA, USA
| | - Gene G Gurkoff
- Department of Neurological Surgery, University of California-DavisSacramento, CA, USA; Center for Neuroscience, University of California-DavisSacramento, CA, USA
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31
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Butler CR, Boychuk JA, Smith BN. Differential effects of rapamycin treatment on tonic and phasic GABAergic inhibition in dentate granule cells after focal brain injury in mice. Exp Neurol 2016; 280:30-40. [PMID: 27018320 DOI: 10.1016/j.expneurol.2016.03.022] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Revised: 03/07/2016] [Accepted: 03/20/2016] [Indexed: 10/22/2022]
Abstract
The cascade of events leading to post-traumatic epilepsy (PTE) after traumatic brain injury (TBI) remains unclear. Altered inhibition in the hippocampal formation and dentate gyrus is a hallmark of several neurological disorders, including TBI and PTE. Inhibitory synaptic signaling in the hippocampus is predominately driven by γ-aminobutyric acid (GABA) neurotransmission, and is prominently mediated by postsynaptic type A GABA receptors (GABAAR's). Subsets of these receptors involved in tonic inhibition of neuronal membranes serve a fundamental role in maintenance of inhibitory state, and GABAAR-mediated tonic inhibition is altered functionally in animal models of both TBI and epilepsy. In this study, we assessed the effect of mTOR inhibition on hippocampal hilar inhibitory interneuron loss and synaptic and tonic GABAergic inhibition of dentate gyrus granule cells (DGCs) after controlled cortical impact (CCI) to determine if mTOR activation after TBI modulates GABAAR function. Hilar inhibitory interneuron density was significantly reduced 72h after CCI injury in the dorsal two-thirds of the hemisphere ipsilateral to injury compared with the contralateral hemisphere and sham controls. Rapamycin treatment did not alter this reduction in cell density. Synaptic and tonic current measurements made in DGCs at both 1-2 and 8-13weeks post-injury indicated reduced synaptic inhibition and THIP-induced tonic current density in DGCs ipsilateral to CCI injury at both time points post-injury, with no change in resting tonic GABAAR-mediated currents. Rapamycin treatment did not alter the reduced synaptic inhibition observed in ipsilateral DGCs 1-2weeks post-CCI injury, but further reduced synaptic inhibition of ipsilateral DGCs at 8-13weeks post-injury. The reduction in THIP-induced tonic current after injury, however, was prevented by rapamycin treatment at both time points. Rapamycin treatment thus differentially modifies CCI-induced changes in synaptic and tonic GABAAR-mediated currents in DGCs.
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Affiliation(s)
- Corwin R Butler
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, KY 40536, United States
| | - Jeffery A Boychuk
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, KY 40536, United States; Epilepsy Center, University of Kentucky, Lexington, KY 40536, United States; Center for Advanced Translational Stroke Science, University of Kentucky, Lexington, KY 40536, United States
| | - Bret N Smith
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, KY 40536, United States; Epilepsy Center, University of Kentucky, Lexington, KY 40536, United States; Spinal Cord and Brain Injury Research Center (SCoBIRC), University of Kentucky, Lexington, KY 40536, United States.
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32
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Enduring changes in tonic GABAA receptor signaling in dentate granule cells after controlled cortical impact brain injury in mice. Exp Neurol 2016; 277:178-189. [DOI: 10.1016/j.expneurol.2016.01.005] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2015] [Revised: 12/16/2015] [Accepted: 01/05/2016] [Indexed: 11/23/2022]
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33
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Alterations of functional properties of hippocampal networks following repetitive closed-head injury. Exp Neurol 2016; 277:227-243. [DOI: 10.1016/j.expneurol.2015.12.019] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2015] [Revised: 12/09/2015] [Accepted: 12/22/2015] [Indexed: 11/16/2022]
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34
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Almeida-Suhett CP, Prager EM, Pidoplichko V, Figueiredo TH, Marini AM, Li Z, Eiden LE, Braga MF. GABAergic interneuronal loss and reduced inhibitory synaptic transmission in the hippocampal CA1 region after mild traumatic brain injury. Exp Neurol 2015; 273:11-23. [DOI: 10.1016/j.expneurol.2015.07.028] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Revised: 07/24/2015] [Accepted: 07/30/2015] [Indexed: 01/07/2023]
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35
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Posttraumatic seizures and epilepsy in adult rats after controlled cortical impact. Epilepsy Res 2015; 117:104-16. [PMID: 26432760 DOI: 10.1016/j.eplepsyres.2015.09.009] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2015] [Revised: 08/26/2015] [Accepted: 09/10/2015] [Indexed: 12/27/2022]
Abstract
Posttraumatic epilepsy (PTE) has been modeled with different techniques of experimental traumatic brain injury (TBI) using mice and rats at various ages. We hypothesized that the technique of controlled cortical impact (CCI) could be used to establish a model of PTE in young adult rats. A total of 156 male Sprague-Dawley rats of 2-3 months of age (128 CCI-injured and 28 controls) was used for monitoring and/or anatomical studies. Provoked class 3-5 seizures were recorded by video monitoring in 7/57 (12.3%) animals in the week immediately following CCI of the right parietal cortex; none of the 7 animals demonstrated subsequent spontaneous convulsive seizures. Monitoring with video and/or video-EEG was performed on 128 animals at various time points 8-619 days beyond one week following CCI during which 26 (20.3%) demonstrated nonconvulsive or convulsive epileptic seizures. Nonconvulsive epileptic seizures of >10s were demonstrated in 7/40 (17.5%) animals implanted with 2 or 3 depth electrodes and usually characterized by an initial change in behavior (head raising or animal alerting) followed by motor arrest during an ictal discharge that consisted of high-amplitude spikes or spike-waves with frequencies ranging between 1 and 2Hz class 3-5 epileptic seizures were recorded by video monitoring in 17/88 (19%) and by video-EEG in 2/40 (5%) CCI-injured animals. Ninety of 156 (58%) animals (79 CCI-injured, 13 controls) underwent transcardial perfusion for gross and microscopic studies. CCI caused severe brain tissue loss and cavitation of the ipsilateral cerebral hemisphere associated with cell loss in the hippocampal CA1 and CA3 regions, hilus, and dentate granule cells, and thalamus. All Timm-stained CCI-injured brains demonstrated ipsilateral hippocampal mossy fiber sprouting in the inner molecular layer. These results indicate that the CCI model of TBI in adult rats can be used to study the structure-function relationships that underlie epileptogenesis and PTE.
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36
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Lee DJ, Gurkoff GG, Izadi A, Seidl SE, Echeverri A, Melnik M, Berman RF, Ekstrom AD, Muizelaar JP, Lyeth BG, Shahlaie K. Septohippocampal Neuromodulation Improves Cognition after Traumatic Brain Injury. J Neurotrauma 2015; 32:1822-32. [PMID: 26096267 DOI: 10.1089/neu.2014.3744] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Traumatic brain injury (TBI) often results in persistent attention and memory deficits that are associated with hippocampal dysfunction. Although deep brain stimulation (DBS) is used to treat neurological disorders related to motor dysfunction, the effectiveness of stimulation to treat cognition remains largely unknown. In this study, adult male Harlan Sprague-Dawley rats underwent a lateral fluid percussion or sham injury followed by implantation of bipolar electrodes in the medial septal nucleus (MSN) and ipsilateral hippocampus. In the first week after injury, there was a significant decrease in hippocampal theta oscillations that correlated with decreased object exploration and impaired performance in the Barnes maze spatial learning task. Continuous 7.7 Hz theta stimulation of the medial septum significantly increased hippocampal theta oscillations, restored normal object exploration, and improved spatial learning in injured animals. There were no benefits with 100 Hz gamma stimulation, and stimulation of sham animals at either frequency did not enhance performance. We conclude, therefore, that there was a theta frequency-specific benefit of DBS that restored cognitive function in brain-injured rats. These data suggest that septal theta stimulation may be an effective and novel neuromodulatory therapy for treatment of persistent cognitive deficits following TBI.
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Affiliation(s)
- Darrin J Lee
- 1 Department of Neurological Surgery, University of California , Davis, Sacramento, California
| | - Gene G Gurkoff
- 1 Department of Neurological Surgery, University of California , Davis, Sacramento, California
| | - Ali Izadi
- 1 Department of Neurological Surgery, University of California , Davis, Sacramento, California
| | | | - Angela Echeverri
- 1 Department of Neurological Surgery, University of California , Davis, Sacramento, California
| | - Mikhail Melnik
- 1 Department of Neurological Surgery, University of California , Davis, Sacramento, California
| | - Robert F Berman
- 1 Department of Neurological Surgery, University of California , Davis, Sacramento, California.,2 Center for Neuroscience, University of California , Davis, Sacramento, California
| | - Arne D Ekstrom
- 2 Center for Neuroscience, University of California , Davis, Sacramento, California
| | - J Paul Muizelaar
- 1 Department of Neurological Surgery, University of California , Davis, Sacramento, California
| | - Bruce G Lyeth
- 1 Department of Neurological Surgery, University of California , Davis, Sacramento, California.,2 Center for Neuroscience, University of California , Davis, Sacramento, California
| | - Kiarash Shahlaie
- 1 Department of Neurological Surgery, University of California , Davis, Sacramento, California.,2 Center for Neuroscience, University of California , Davis, Sacramento, California
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37
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Raible DJ, Frey LC, Del Angel YC, Carlsen J, Hund D, Russek SJ, Smith B, Brooks-Kayal AR. JAK/STAT pathway regulation of GABAA receptor expression after differing severities of experimental TBI. Exp Neurol 2015; 271:445-56. [PMID: 26172316 PMCID: PMC5969808 DOI: 10.1016/j.expneurol.2015.07.001] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2015] [Revised: 06/22/2015] [Accepted: 07/04/2015] [Indexed: 01/07/2023]
Abstract
Synaptic inhibition in the adult brain is primarily mediated by the γ-aminobutyric acid (GABA) type A receptor (GABA(A)R). The distribution, properties, and dynamics of these receptors are largely determined by their subunit composition. Alteration of subunit composition after a traumatic brain injury (TBI) may result in abnormal increased synaptic firing and possibly contribute to injury-related pathology. Several studies have shown that the Janus Kinase/Signal Transducer and Activator of Transcription (JAK/STAT) signaling pathway can alter GABA(A)R subunit expression. The present study investigated changes in JAK/STAT pathway activation after two different severities of experimental TBI in the mouse using the controlled cortical impact (CCI) model. It also investigated whether modulating the activation of the JAK/STAT pathway after severe controlled cortical impact (CCI-S) with a JAK/STAT inhibitor (WP1066) alters post-traumatic epilepsy development and/or neurological recovery after injury. Our results demonstrated differential changes in both the activation of STAT3 and the expression of the GABA(A)R α1 and γ2 subunit levels that were dependent on the severity of the injury. The change in the GABA(A)R α1 subunit levels appeared to be at least partly transcriptionally mediated. We were able to selectively reverse the decrease in GABA(A)R α1 protein levels with WP1066 treatment after CCI injury. WP1066 treatment also improved the degree of recovery of vestibular motor function after injury. These findings suggest that the magnitude of JAK/STAT pathway activation and GABA(A)R α1 subunit level decrease is dependent on injury severity in this mouse model of TBI. In addition, reducing JAK/STAT pathway activation after severe experimental TBI reverses the decrease in the GABA(A)R α1 protein levels and improves vestibular motor recovery.
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Affiliation(s)
- Daniel J Raible
- Neuroscience Program, University of Colorado, Anschutz Medical Campus, Aurora, CO, United States.
| | - Lauren C Frey
- Department of Neurology, University of Colorado School of Medicine, Aurora, CO, United States.
| | - Yasmin Cruz Del Angel
- Division of Neurology, Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO, United States.
| | - Jessica Carlsen
- Division of Neurology, Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO, United States.
| | - Dana Hund
- Division of Neurology, Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO, United States.
| | - Shelley J Russek
- Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, MA, United States.
| | - Bret Smith
- Department of Physiology, College of Medicine, University of Kentucky, MS508 Chandler Medical Center, 800 Rose Street, Lexington, KY 40536, United States.
| | - Amy R Brooks-Kayal
- Neuroscience Program, University of Colorado, Anschutz Medical Campus, Aurora, CO, United States; Department of Neurology, University of Colorado School of Medicine, Aurora, CO, United States; Division of Neurology, Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO, United States; Children's Hospital Colorado, Aurora, CO, United States.
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38
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Boychuk CR, Halmos KC, Smith BN. Diabetes induces GABA receptor plasticity in murine vagal motor neurons. J Neurophysiol 2015; 114:698-706. [PMID: 25995347 DOI: 10.1152/jn.00209.2015] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Accepted: 05/19/2015] [Indexed: 01/07/2023] Open
Abstract
Autonomic dysregulation accompanies type-1 diabetes, and synaptic regulation of parasympathetic preganglionic motor neurons in the dorsal motor nucleus of the vagus (DMV) is altered after chronic hyperglycemia/hypoinsulinemia. Tonic gamma-aminobutyric acid A (GABAA) inhibition prominently regulates DMV neuron activity, which contributes to autonomic control of energy homeostasis. This study investigated persistent effects of chronic hyperglycemia/hypoinsulinemia on GABAA receptor-mediated inhibition in the DMV after streptozotocin-induced type-1 diabetes using electrophysiological recordings in vitro, quantitative (q)RT-PCR, and immunohistochemistry. Application of the nonspecific GABAA receptor agonist muscimol evoked an outward current of significantly larger amplitude in DMV neurons from diabetic mice than controls. Results from application of 4,5,6,7-tetrahydroisoxazolo[5,4-c]pyridin-3-ol hydrochloride (THIP), a δ-subunit agonist, suggested that GABAA receptors containing δ-subunits contributed to the enhanced inducible tonic GABA current in diabetic mice. Sensitivity to THIP of inhibitory postsynaptic currents in DMV neurons from diabetic mice was also increased. Results from qRT-PCR and immunohistochemical analyses indicated that the altered GABAergic inhibition may be related to increased trafficking of GABAA receptors that contain the δ-subunit, rather than an expression change. Overall these findings suggest increased sensitivity of δ-subunit containing GABAA receptors after several days of hyperglycemia/hypoinsulinemia, which dramatically alters GABAergic inhibition of DMV neurons and could contribute to diabetic autonomic dysregulation.
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Affiliation(s)
- C R Boychuk
- Department of Physiology, University of Kentucky College of Medicine, Lexington, Kentucky
| | - K Cs Halmos
- Department of Physiology, University of Kentucky College of Medicine, Lexington, Kentucky
| | - B N Smith
- Department of Physiology, University of Kentucky College of Medicine, Lexington, Kentucky
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39
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Abstract
This review presents a brief overview of the γ-aminobutyric acid (GABA) system in the developing and mature central nervous system (CNS) and its potential connections to pathologies of the CNS. γ-aminobutyric acid (GABA) is a major neurotransmitter expressed from the embryonic stage and throughout life. At an early developmental stage, GABA acts in an excitatory manner and is implicated in many processes of neurogenesis, including neuronal proliferation, migration, differentiation, and preliminary circuit-building, as well as the development of critical periods. In the mature CNS, GABA acts in an inhibitory manner, a switch mediated by chloride/cation transporter expression and summarized in this review. GABA also plays a role in the development of interstitial neurons of the white matter, as well as in oligodendrocyte development. Although the underlying cellular mechanisms are not yet well understood, we present current findings for the role of GABA in neurological diseases with characteristic white matter abnormalities, including anoxic-ischemic injury, periventricular leukomalacia, and schizophrenia. Development abnormalities of the GABAergic system appear particularly relevant in the etiology of schizophrenia. This review also covers the potential role of GABA in mature brain injury, namely transient ischemia, stroke, and traumatic brain injury/post-traumatic epilepsy.
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Affiliation(s)
- Connie Wu
- Department of Neuroscience, University of Wisconsin-Madison, Madison, WI 53706
| | - Dandan Sun
- Department of Neurology, University of Pittsburgh, Pittsburgh, PA 15213, USA
- Veterans Affairs Pittsburgh Health Care System, Geriatric Research, Educational and Clinical Center, Pittsburgh, PA 15213, USA
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40
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Altered expression of δGABAA receptors in health and disease. Neuropharmacology 2014; 88:24-35. [PMID: 25128850 DOI: 10.1016/j.neuropharm.2014.08.003] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2014] [Revised: 07/28/2014] [Accepted: 08/03/2014] [Indexed: 01/08/2023]
Abstract
γ-Aminobutyric acid type A receptors that contain the δ subunit (δGABAA receptors) are expressed in multiple types of neurons throughout the central nervous system, where they generate a tonic conductance that shapes neuronal excitability and synaptic plasticity. These receptors regulate a variety of important behavioral functions, including memory, nociception and anxiety, and may also modulate neurogenesis. Given their functional significance, δGABAA receptors are considered to be novel therapeutic targets for the treatment of memory dysfunction, pain, insomnia and mood disorders. These receptors are highly responsive to sedative-hypnotic drugs, general anesthetics and neuroactive steroids. A further remarkable feature of δGABAA receptors is that their expression levels are highly dynamic and fluctuate substantially during development and in response to physiological changes including stress and the reproductive cycle. Furthermore, the expression of these receptors varies in pathological conditions such as alcoholism, fragile X syndrome, epilepsy, depression, schizophrenia, mood disorders and traumatic brain injury. Such fluctuations in receptor expression have significant consequences for behavior and may alter responsiveness to therapeutic drugs. This review considers the alterations in the expression of δGABAA receptors associated with various states of health and disease and the implications of these changes.
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Boddum K, Frølund B, Kristiansen U. The GABAA Antagonist DPP-4-PIOL Selectively Antagonises Tonic over Phasic GABAergic Currents in Dentate Gyrus Granule Cells. Neurochem Res 2014; 39:2078-84. [DOI: 10.1007/s11064-014-1397-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2014] [Revised: 07/18/2014] [Accepted: 07/18/2014] [Indexed: 11/30/2022]
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Cantu D, Walker K, Andresen L, Taylor-Weiner A, Hampton D, Tesco G, Dulla CG. Traumatic Brain Injury Increases Cortical Glutamate Network Activity by Compromising GABAergic Control. Cereb Cortex 2014; 25:2306-20. [PMID: 24610117 DOI: 10.1093/cercor/bhu041] [Citation(s) in RCA: 134] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Traumatic brain injury (TBI) is a major risk factor for developing pharmaco-resistant epilepsy. Although disruptions in brain circuitry are associated with TBI, the precise mechanisms by which brain injury leads to epileptiform network activity is unknown. Using controlled cortical impact (CCI) as a model of TBI, we examined how cortical excitability and glutamatergic signaling was altered following injury. We optically mapped cortical glutamate signaling using FRET-based glutamate biosensors, while simultaneously recording cortical field potentials in acute brain slices 2-4 weeks following CCI. Cortical electrical stimulation evoked polyphasic, epileptiform field potentials and disrupted the input-output relationship in deep layers of CCI-injured cortex. High-speed glutamate biosensor imaging showed that glutamate signaling was significantly increased in the injured cortex. Elevated glutamate responses correlated with epileptiform activity, were highest directly adjacent to the injury, and spread via deep cortical layers. Immunoreactivity for markers of GABAergic interneurons were significantly decreased throughout CCI cortex. Lastly, spontaneous inhibitory postsynaptic current frequency decreased and spontaneous excitatory postsynaptic current increased after CCI injury. Our results suggest that specific cortical neuronal microcircuits may initiate and facilitate the spread of epileptiform activity following TBI. Increased glutamatergic signaling due to loss of GABAergic control may provide a mechanism by which TBI can give rise to post-traumatic epilepsy.
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Affiliation(s)
- David Cantu
- Department of Neuroscience, Tufts University School of Medicine, SC201, Boston, MA 02111, USA
| | - Kendall Walker
- Department of Neuroscience, Alzheimer's Disease Research Laboratory, Tufts University School of Medicine, A305, Boston, MA 02111, USA
| | - Lauren Andresen
- Department of Neuroscience, Tufts University School of Medicine, SC201, Boston, MA 02111, USA Program in Neuroscience at the Sackler School of Biomedical Sciences, Tufts University
| | - Amaro Taylor-Weiner
- Department of Neuroscience, Tufts University School of Medicine, SC201, Boston, MA 02111, USA Current address: Broad Institute, Cambridge, MA 02142, USA
| | - David Hampton
- Department of Neuroscience, Tufts University School of Medicine, SC201, Boston, MA 02111, USA
| | - Giuseppina Tesco
- Department of Neuroscience, Alzheimer's Disease Research Laboratory, Tufts University School of Medicine, A305, Boston, MA 02111, USA
| | - Chris G Dulla
- Department of Neuroscience, Tufts University School of Medicine, SC201, Boston, MA 02111, USA
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Abstract
There are more than 3.17 million people coping with long-term disabilities due to traumatic brain injury (TBI) in the United States. The majority of TBI research is focused on developing acute neuroprotective treatments to prevent or minimize these long-term disabilities. Therefore, chronic TBI survivors represent a large, underserved population that could significantly benefit from a therapy that capitalizes on the endogenous recovery mechanisms occurring during the weeks to months following brain trauma. Previous studies have found that the hippocampus is highly vulnerable to brain injury, in both experimental models of TBI and during human TBI. Although often not directly mechanically injured by the head injury, in the weeks to months following TBI, the hippocampus undergoes atrophy and exhibits deficits in long-term potentiation (LTP), a persistent increase in synaptic strength that is considered to be a model of learning and memory. Decoding the chronic hippocampal LTP and cell signaling deficits after brain trauma will provide new insights into the molecular mechanisms of hippocampal-dependent learning impairments caused by TBI and facilitate the development of effective therapeutic strategies to improve hippocampal-dependent learning for chronic survivors of TBI.
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Affiliation(s)
- Coleen M Atkins
- The Miami Project to Cure Paralysis, Department of Neurological Surgery, University of Miami Miller School of Medicine, Miami, FL 33136, USA
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Carver CM, Reddy DS. Neurosteroid interactions with synaptic and extrasynaptic GABA(A) receptors: regulation of subunit plasticity, phasic and tonic inhibition, and neuronal network excitability. Psychopharmacology (Berl) 2013; 230:151-88. [PMID: 24071826 PMCID: PMC3832254 DOI: 10.1007/s00213-013-3276-5] [Citation(s) in RCA: 171] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2013] [Accepted: 08/29/2013] [Indexed: 12/25/2022]
Abstract
RATIONALE Neurosteroids are steroids synthesized within the brain with rapid effects on neuronal excitability. Allopregnanolone, allotetrahydrodeoxycorticosterone, and androstanediol are three widely explored prototype endogenous neurosteroids. They have very different targets and functions compared to conventional steroid hormones. Neuronal γ-aminobutyric acid (GABA) type A (GABA(A)) receptors are one of the prime molecular targets of neurosteroids. OBJECTIVE This review provides a critical appraisal of recent advances in the pharmacology of endogenous neurosteroids that interact with GABA(A) receptors in the brain. Neurosteroids possess distinct, characteristic effects on the membrane potential and current conductance of the neuron, mainly via potentiation of GABA(A) receptors at low concentrations and direct activation of receptor chloride channel at higher concentrations. The GABA(A) receptor mediates two types of inhibition, now characterized as synaptic (phasic) and extrasynaptic (tonic) inhibition. Synaptic release of GABA results in the activation of low-affinity γ2-containing synaptic receptors, while high-affinity δ-containing extrasynaptic receptors are persistently activated by the ambient GABA present in the extracellular fluid. Neurosteroids are potent positive allosteric modulators of synaptic and extrasynaptic GABA(A) receptors and therefore enhance both phasic and tonic inhibition. Tonic inhibition is specifically more sensitive to neurosteroids. The resulting tonic conductance generates a form of shunting inhibition that controls neuronal network excitability, seizure susceptibility, and behavior. CONCLUSION The growing understanding of the mechanisms of neurosteroid regulation of the structure and function of the synaptic and extrasynaptic GABA(A) receptors provides many opportunities to create improved therapies for sleep, anxiety, stress, epilepsy, and other neuropsychiatric conditions.
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Affiliation(s)
- Chase Matthew Carver
- Department of Neuroscience and Experimental Therapeutics, College of Medicine, Texas A&M University Health Science Center, 2008 Medical Research and Education Building, 8447 State Highway 47, Bryan, TX, 77807-3260, USA
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Smith SS. α4βδ GABAA receptors and tonic inhibitory current during adolescence: effects on mood and synaptic plasticity. Front Neural Circuits 2013; 7:135. [PMID: 24027497 PMCID: PMC3759753 DOI: 10.3389/fncir.2013.00135] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2013] [Accepted: 07/28/2013] [Indexed: 11/13/2022] Open
Abstract
The onset of puberty is associated with alterations in mood as well as changes in cognitive function, which can be more pronounced in females. Puberty onset in female mice is associated with increased expression of α4βδ γ-amino-butyric acid-A (GABAA) receptors (GABARs) in CA1 hippocampus. These receptors, which normally have low expression in this central nervous system (CNS) site, emerge along the apical dendrites as well as on the dendritic spines of pyramidal neurons, adjacent to excitatory synapses where they underlie a tonic inhibition that shunts excitatory current and impairs activation of N-methyl-D-aspartate (NMDA) receptors, the trigger for synaptic plasticity. As would be expected, α4βδ expression at puberty also prevents long-term potentiation (LTP), an in vitro model of learning which is a function of network activity, induced by theta burst stimulation of the Schaffer collaterals to the CA1 hippocampus. The expression of these receptors also impairs spatial learning in a hippocampal-dependent task. These impairments are not seen in δ knock-out (-/-) mice, implicating α4βδ GABARs. α4βδ GABARs are also a sensitive target for steroids such as THP ([allo]pregnanolone or 3α-OH-5α[β]-pregnan-20-one), which are dependent upon the polarity of GABAergic current. It is well-known that THP can increase depolarizing current gated by α4βδ GABARs, but more recent data suggest that THP can reduce hyperpolarizing current by accelerating receptor desensitization. At puberty, THP reduces the hyperpolarizing GABAergic current, which removes the shunting inhibition that impairs synaptic plasticity and learning at this time. However, THP, a stress steroid, also increases anxiety, via its action at α4βδ GABARs because it is not seen in δ(-/-) mice. These findings will be discussed as well as their relevance to changes in mood and cognition at puberty, which can be a critical period for certain types of learning and when anxiety disorders and mood swings can emerge.
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Affiliation(s)
- Sheryl S Smith
- Department of Physiology and Pharmacology, SUNY Downstate Medical Center Brooklyn, NY 11203, USA.
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Shen H, Mohammad A, Ramroop J, Smith SS. A stress steroid triggers anxiety via increased expression of α4βδ GABAA receptors in methamphetamine dependence. Neuroscience 2013; 254:452-75. [PMID: 23994152 DOI: 10.1016/j.neuroscience.2013.08.033] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2012] [Revised: 08/13/2013] [Accepted: 08/20/2013] [Indexed: 10/26/2022]
Abstract
Methamphetamine (METH) is an addictive stimulant drug. In addition to drug craving and lethargy, METH withdrawal is associated with stress-triggered anxiety. However, the cellular basis for this stress-triggered anxiety is not understood. The present results suggest that during METH withdrawal (24h) following chronic exposure (3mg/kg, i.p. for 3-5weeks) of adult, male mice, the effect of one neurosteroid released by stress, 3α,5α-THP (3α-OH-5α-pregnan-20-one), and its 3α,5β isomer reverse to trigger anxiety assessed by the acoustic startle response (ASR), in contrast to their usual anti-anxiety effects. This novel effect of 3α,5β-THP was due to increased (three-fold) hippocampal expression of α4βδ GABAA receptors (GABARs) during METH withdrawal (24h-4weeks) because anxiogenic effects of 3α,5β-THP were not seen in α4-/- mice. 3α,5β-THP reduces current at these receptors when it is hyperpolarizing, as observed during METH withdrawal. As a result, 3α,5β-THP (30nM) increased neuronal excitability, assessed with current clamp and cell-attached recordings in CA1hippocampus, one CNS site which regulates anxiety. α4βδ GABARs were first increased 1h after METH exposure and recovered 6weeks after METH withdrawal. Similar increases in α4βδ GABARs and anxiogenic effects of 3α,5β-THP were noted in rats during METH withdrawal (24h). In contrast, the ASR was increased by chronic METH treatment in the absence of 3α,5β-THP administration due to its stimulant effect. Although α4βδ GABARs were increased by chronic METH treatment, the GABAergic current recorded from hippocampal neurons at this time was a depolarizing, shunting inhibition, which was potentiated by 3α,5β-THP. This steroid reduced neuronal excitability and anxiety during chronic METH treatment, consistent with its typical effect. Flumazenil (10mg/kg, i.p., 3×) reduced α4βδ expression and prevented the anxiogenic effect of 3α,5β-THP after METH withdrawal. Our findings suggest a novel mechanism underlying stress-triggered anxiety after METH withdrawal mediated by α4βδ GABARs.
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Affiliation(s)
- H Shen
- Department of Physiology and Pharmacology, SUNY Downstate Medical Center, 450 Clarkson Avenue, Brooklyn, NY 11203, United States
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47
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Biomarkers of cognitive dysfunction in traumatic brain injury. J Neural Transm (Vienna) 2013; 121:79-90. [DOI: 10.1007/s00702-013-1078-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2013] [Accepted: 07/30/2013] [Indexed: 12/11/2022]
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Hunt RF, Boychuk JA, Smith BN. Neural circuit mechanisms of post-traumatic epilepsy. Front Cell Neurosci 2013; 7:89. [PMID: 23785313 PMCID: PMC3684786 DOI: 10.3389/fncel.2013.00089] [Citation(s) in RCA: 104] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Accepted: 05/22/2013] [Indexed: 01/13/2023] Open
Abstract
Traumatic brain injury (TBI) greatly increases the risk for a number of mental health problems and is one of the most common causes of medically intractable epilepsy in humans. Several models of TBI have been developed to investigate the relationship between trauma, seizures, and epilepsy-related changes in neural circuit function. These studies have shown that the brain initiates immediate neuronal and glial responses following an injury, usually leading to significant cell loss in areas of the injured brain. Over time, long-term changes in the organization of neural circuits, particularly in neocortex and hippocampus, lead to an imbalance between excitatory and inhibitory neurotransmission and increased risk for spontaneous seizures. These include alterations to inhibitory interneurons and formation of new, excessive recurrent excitatory synaptic connectivity. Here, we review in vivo models of TBI as well as key cellular mechanisms of synaptic reorganization associated with post-traumatic epilepsy (PTE). The potential role of inflammation and increased blood-brain barrier permeability in the pathophysiology of PTE is also discussed. A better understanding of mechanisms that promote the generation of epileptic activity versus those that promote compensatory brain repair and functional recovery should aid development of successful new therapies for PTE.
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Affiliation(s)
- Robert F Hunt
- Epilepsy Research Laboratory, Department of Neurological Surgery, University of California San Francisco, CA, USA
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49
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Abstract
Activation of GABA(A) receptors (GABA(A)Rs) produces two forms of inhibition: phasic inhibition generated by the rapid, transient activation of synaptic GABA(A)Rs by presynaptic GABA release, and tonic inhibition generated by the persistent activation of perisynaptic or extrasynaptic GABA(A)Rs, which can detect extracellular GABA. Such tonic GABA(A)R-mediated currents are particularly evident in dentate granule cells in which they play a major role in regulating cell excitability. Here we show that in rat dentate granule cells in ex vivo hippocampal slices, tonic currents are predominantly generated by GABA-independent GABA(A) receptor openings. This tonic GABA(A)R conductance is resistant to the competitive GABA(A)R antagonist SR95531 (gabazine), which at high concentrations acts as a partial agonist, but can be blocked by an open channel blocker, picrotoxin. When slices are perfused with 200 nm GABA, a concentration that is comparable to CSF concentrations but is twice that measured by us in the hippocampus in vivo using zero-net-flux microdialysis, negligible GABA is detected by dentate granule cells. Spontaneously opening GABA(A)Rs, therefore, maintain dentate granule cell tonic currents in the face of low extracellular GABA concentrations.
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50
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Raible DJ, Frey LC, Cruz Del Angel Y, Russek SJ, Brooks-Kayal AR. GABA(A) receptor regulation after experimental traumatic brain injury. J Neurotrauma 2012; 29:2548-54. [PMID: 22827467 DOI: 10.1089/neu.2012.2483] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The gamma-aminobutyric acid (GABA) type A receptor (GABA(A)R) is responsible for most fast synaptic inhibition in the adult brain. The GABA(A)R protein is composed of multiple subunits that determine the distribution, properties, and dynamics of the receptor. Several studies have shown that the Janus kinase/signal transducer and activator of transcription (JaK/STAT) and early growth response 3 (Egr3) signaling pathways can alter GABA(A)R subunit expression after status epilepticus (SE). In this study we investigated changes in these pathways after experimental TBI in the rat using a lateral fluid percussion injury (FPI) model. Our results demonstrated changes in the expression of several GABA(A)R subunit levels after injury, including GABA(A)R α1 and α4 subunits. This change appears to be transcriptional, and there is an associated increase in the phosphorylation of STAT3, and an increase in the expression of Egr3 and inducible cAMP element repressor (ICER) after FPI. These findings suggest that the activation of the JaK/STAT and Egr3 pathways after TBI may regulate injury-related changes in GABA(A)R subunit expression.
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Affiliation(s)
- Daniel J Raible
- Neuroscience Program, University of Colorado, Anschutz Medical Campus, Aurora, Colorado, USA
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