1
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Lado WE, Xu X, Hablitz JJ. Modulation of Epileptiform Activity by Three Subgroups of GABAergic Interneurons in Mouse Somatosensory Cortex. Epilepsy Res 2022; 183:106937. [DOI: 10.1016/j.eplepsyres.2022.106937] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Revised: 04/05/2022] [Accepted: 04/24/2022] [Indexed: 11/29/2022]
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2
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An inventory of basic research in temporal lobe epilepsy. Rev Neurol (Paris) 2021; 177:1069-1081. [PMID: 34176659 DOI: 10.1016/j.neurol.2021.02.390] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 01/26/2021] [Accepted: 02/05/2021] [Indexed: 12/25/2022]
Abstract
Temporal lobe epilepsy is a severe neurological disease, characterized by seizure occurrence and invalidating cognitive co-morbidities, which affects up to 1% of the adults. Roughly one third of the patients are resistant to any conventional pharmacological treatments. The last option in that case is the surgical removal of the epileptic focus, with no guarantee for clinical symptom alleviation. This state of affairs requests the identification of cellular or molecular targets for novel therapeutic approaches with limited side effects. Here we review some generalities about the disease as well as some of the most recent discoveries about the cellular and molecular mechanisms of TLE, and the latest perspectives for novel treatments.
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3
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Duffy BA, Choy M, Lee JH. Predicting Successful Generation and Inhibition of Seizure-like Afterdischarges and Mapping Their Seizure Networks Using fMRI. Cell Rep 2021; 30:2540-2554.e4. [PMID: 32101734 DOI: 10.1016/j.celrep.2020.01.095] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Revised: 12/18/2019] [Accepted: 01/27/2020] [Indexed: 11/30/2022] Open
Abstract
To understand the conditions necessary to initiate and terminate seizures, we investigate optogenetically induced hippocampal seizures with LFP, fMRI, and optogenetic inhibition. During afterdischarge induction using optogenetics, LFP recordings show that stimulations with earlier ictal onset times are more likely to result in afterdischarges and are more difficult to curtail with optogenetic inhibition. These results are generalizable across two initiation sites, the dorsal and ventral hippocampus. fMRI shows that afterdischarges initiated from the dorsal or ventral hippocampus exhibit distinct networks. Short-duration seizures initiated in the dorsal and ventral hippocampus are unilateral and bilateral, respectively, while longer-duration afterdischarges recruit broader, bilateral networks. When optogenetic inhibition is ineffective at stopping seizures, the network activity spreads more extensively but largely overlaps with the network activity associated with seizures that could be curtailed. These results provide insights into how seizures can be inhibited, which has implications for targeted seizure interventions.
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Affiliation(s)
- Ben A Duffy
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA 94305, USA
| | - ManKin Choy
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA 94305, USA
| | - Jin Hyung Lee
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA 94305, USA; Department of Bioengineering, Stanford University, Stanford, CA 94305, USA; Department of Neurosurgery, Stanford University, Stanford, CA 94305, USA; Department of Electrical Engineering, Stanford University, Stanford, CA 94305, USA.
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4
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Gao Y, Zheng J, Jiang T, Pi G, Sun F, Xiong R, Wang W, Wu D, Li S, Lei H, Yu H, Zhou Q, Yang Y, Zhang H, Wang JZ. Targeted Reducing of Tauopathy Alleviates Epileptic Seizures and Spatial Memory Impairment in an Optogenetically Inducible Mouse Model of Epilepsy. Front Cell Dev Biol 2021; 8:633725. [PMID: 33681188 PMCID: PMC7930339 DOI: 10.3389/fcell.2020.633725] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Accepted: 12/29/2020] [Indexed: 11/13/2022] Open
Abstract
Intracellular deposition of hyperphosphorylated tau has been reported in the brain of epilepsy patients, but its contribution to epileptic seizures and the association with spatial cognitive functions remain unclear. Here, we found that repeated optogenetic stimulation of the excitatory neurons in ventral hippocampal CA1 subset could induce a controllable epileptic seizure in mice. Simultaneously, the mice showed spatial learning and memory deficits with a prominently elevated total tau and phospho-tau levels in the brain. Importantly, selective facilitating tau degradation by using a novel designed proteolysis-targeting chimera named C4 could effectively ameliorate the epileptic seizures with remarkable restoration of neuronal firing activities and improvement of spatial learning and memory functions. These results confirm that abnormal tau accumulation plays a pivotal role in the epileptic seizures and the epilepsy-associated spatial memory impairments, which provides new molecular target for the therapeutics.
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Affiliation(s)
- Yang Gao
- Department of Pathophysiology, Key Laboratory of Ministry of Education for Neurological Disorders, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Jie Zheng
- Department of Pathophysiology, Key Laboratory of Ministry of Education for Neurological Disorders, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Department of Pharmacology, Key Laboratory of Basic Pharmacology of Ministry of Education and Joint International Research Laboratory of Ethnomedicine of Ministry of Education, Zunyi Medical University, Zunyi, China
| | - Tao Jiang
- Department of Pathophysiology, Key Laboratory of Ministry of Education for Neurological Disorders, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Guilin Pi
- Department of Pathophysiology, Key Laboratory of Ministry of Education for Neurological Disorders, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Fei Sun
- Department of Pathophysiology, Key Laboratory of Ministry of Education for Neurological Disorders, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Rui Xiong
- Department of Pathophysiology, Key Laboratory of Ministry of Education for Neurological Disorders, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Weijin Wang
- Department of Pathophysiology, Key Laboratory of Ministry of Education for Neurological Disorders, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Dongqin Wu
- Department of Pathophysiology, Key Laboratory of Ministry of Education for Neurological Disorders, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Shihong Li
- Department of Pathophysiology, Key Laboratory of Ministry of Education for Neurological Disorders, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Huiyang Lei
- Department of Pathophysiology, Key Laboratory of Ministry of Education for Neurological Disorders, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Huiling Yu
- Department of Pathophysiology, Key Laboratory of Ministry of Education for Neurological Disorders, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Qiuzhi Zhou
- Department of Pathophysiology, Key Laboratory of Ministry of Education for Neurological Disorders, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Ying Yang
- Department of Pathophysiology, Key Laboratory of Ministry of Education for Neurological Disorders, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Huaqiu Zhang
- Department of Neurosurgery, Key Laboratory of Ministry of Education for Neurological Disorders, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Jian-Zhi Wang
- Department of Pathophysiology, Key Laboratory of Ministry of Education for Neurological Disorders, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Co-innovation Center of Neuroregeneration, Nantong University, Nantong, China
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5
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Vandekerckhove B, Missinne J, Vonck K, Bauwens P, Verplancke R, Boon P, Raedt R, Vanfleteren J. Technological Challenges in the Development of Optogenetic Closed-Loop Therapy Approaches in Epilepsy and Related Network Disorders of the Brain. MICROMACHINES 2020; 12:38. [PMID: 33396287 PMCID: PMC7824489 DOI: 10.3390/mi12010038] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Revised: 12/24/2020] [Accepted: 12/28/2020] [Indexed: 12/25/2022]
Abstract
Epilepsy is a chronic, neurological disorder affecting millions of people every year. The current available pharmacological and surgical treatments are lacking in overall efficacy and cause side-effects like cognitive impairment, depression, tremor, abnormal liver and kidney function. In recent years, the application of optogenetic implants have shown promise to target aberrant neuronal circuits in epilepsy with the advantage of both high spatial and temporal resolution and high cell-specificity, a feature that could tackle both the efficacy and side-effect problems in epilepsy treatment. Optrodes consist of electrodes to record local field potentials and an optical component to modulate neurons via activation of opsin expressed by these neurons. The goal of optogenetics in epilepsy is to interrupt seizure activity in its earliest state, providing a so-called closed-loop therapeutic intervention. The chronic implantation in vivo poses specific demands for the engineering of therapeutic optrodes. Enzymatic degradation and glial encapsulation of implants may compromise long-term recording and sufficient illumination of the opsin-expressing neural tissue. Engineering efforts for optimal optrode design have to be directed towards limitation of the foreign body reaction by reducing the implant's elastic modulus and overall size, while still providing stable long-term recording and large-area illumination, and guaranteeing successful intracerebral implantation. This paper presents an overview of the challenges and recent advances in the field of electrode design, neural-tissue illumination, and neural-probe implantation, with the goal of identifying a suitable candidate to be incorporated in a therapeutic approach for long-term treatment of epilepsy patients.
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Affiliation(s)
- Bram Vandekerckhove
- Center for Microsystems Technology, Imec and Ghent University, 9000 Ghent, Belgium; (B.V.); (J.M.); (P.B.); (R.V.)
| | - Jeroen Missinne
- Center for Microsystems Technology, Imec and Ghent University, 9000 Ghent, Belgium; (B.V.); (J.M.); (P.B.); (R.V.)
| | - Kristl Vonck
- 4Brain Team, Department of Head and Skin, Ghent University, 9000 Ghent, Belgium; (K.V.); (P.B.); (R.R.)
| | - Pieter Bauwens
- Center for Microsystems Technology, Imec and Ghent University, 9000 Ghent, Belgium; (B.V.); (J.M.); (P.B.); (R.V.)
| | - Rik Verplancke
- Center for Microsystems Technology, Imec and Ghent University, 9000 Ghent, Belgium; (B.V.); (J.M.); (P.B.); (R.V.)
| | - Paul Boon
- 4Brain Team, Department of Head and Skin, Ghent University, 9000 Ghent, Belgium; (K.V.); (P.B.); (R.R.)
| | - Robrecht Raedt
- 4Brain Team, Department of Head and Skin, Ghent University, 9000 Ghent, Belgium; (K.V.); (P.B.); (R.R.)
| | - Jan Vanfleteren
- Center for Microsystems Technology, Imec and Ghent University, 9000 Ghent, Belgium; (B.V.); (J.M.); (P.B.); (R.V.)
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6
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Optogenetic control of perforant pathway kindled seizures by photoinhibition of CA3 after insertion of Jaws into CA3 neuronal cells. Exp Neurol 2020; 328:113280. [DOI: 10.1016/j.expneurol.2020.113280] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 02/28/2020] [Accepted: 03/03/2020] [Indexed: 11/21/2022]
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7
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Delaney SL, Gendreau JL, D'Souza M, Feng AY, Ho AL. Optogenetic Modulation for the Treatment of Traumatic Brain Injury. Stem Cells Dev 2020; 29:187-197. [DOI: 10.1089/scd.2019.0187] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Affiliation(s)
| | | | | | - Austin Y. Feng
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, Georgia
| | - Allen L. Ho
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, Georgia
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8
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Wang M, Xia Q, Peng F, Jiang B, Chen L, Wu X, Zheng X, Wang X, Tian T, Hou W. Prolonged post-stimulation response induced by 980-nm infrared neural stimulation in the rat primary motor cortex. Lasers Med Sci 2019; 35:365-372. [PMID: 31222480 DOI: 10.1007/s10103-019-02826-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Accepted: 05/31/2019] [Indexed: 11/25/2022]
Abstract
The post-stimulation response of neural activities plays an important role to evaluate the effectiveness and safety of neural modulation techniques. Previous studies have established the capability of infrared neural modulation (INM) on neural firing regulation in the central nervous system (CNS); however, the dynamic neural activity after the laser offset has not been well characterized yet. We applied 980-nm infrared diode laser light to irradiate the primary motor cortex of rats, and tungsten electrode was inserted to record the single-unit activity of neurons at the depth of 800-1000 μm (layer V of primary motor cortex). The neural activities were assessed through the change of neural firing rate and firing pattern pre- and post-stimulation with various radiant exposures. The results showed that the 980-nm laser could modulate the firing properties of neurons in the deep layer of the cortex. More neurons with post-stimulation response (78% vs. 83%) were observed at higher stimulation intensity (0.803 J/cm2 vs. 1.071 J/cm2, respectively). The change of firing rate also increased with radiant exposures increasing, and the response lasted up to 4.5 s at 1.071 J/cm2, which was significantly longer than the theoretical thermal relaxation time. Moreover, the increasing Fano factors indicated the irregularity firing pattern of post-stimulation response. Our results confirmed that neural activity maintained a prolonged post-stimulation response after INM, which may provide necessary measurable data for optimization of INM applications in CNS.
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Affiliation(s)
- Manqing Wang
- Key Laboratory of Biorheological Science and Technology of Ministry of Education, Chongqing University, Chongqing, 400044, China
| | - Qingling Xia
- Key Laboratory of Biorheological Science and Technology of Ministry of Education, Chongqing University, Chongqing, 400044, China
| | - Fei Peng
- Key Laboratory of Biorheological Science and Technology of Ministry of Education, Chongqing University, Chongqing, 400044, China
| | - Bin Jiang
- Key Laboratory of Biorheological Science and Technology of Ministry of Education, Chongqing University, Chongqing, 400044, China
| | - Lin Chen
- Key Laboratory of Biorheological Science and Technology of Ministry of Education, Chongqing University, Chongqing, 400044, China
- Chongqing Medical Electronics Engineering Technology Research Center, Chongqing University, Chongqing 400044, China
| | - Xiaoying Wu
- Key Laboratory of Biorheological Science and Technology of Ministry of Education, Chongqing University, Chongqing, 400044, China
- Chongqing Collaborative Innovation Center for Brain Science, Chongqing University, Chongqing 400044, China
| | - Xiaolin Zheng
- Key Laboratory of Biorheological Science and Technology of Ministry of Education, Chongqing University, Chongqing, 400044, China
- Chongqing Medical Electronics Engineering Technology Research Center, Chongqing University, Chongqing 400044, China
| | - Xing Wang
- Key Laboratory of Biorheological Science and Technology of Ministry of Education, Chongqing University, Chongqing, 400044, China
- Chongqing Medical Electronics Engineering Technology Research Center, Chongqing University, Chongqing 400044, China
- Chongqing Collaborative Innovation Center for Brain Science, Chongqing University, Chongqing 400044, China
| | - Tian Tian
- Key Laboratory of Biorheological Science and Technology of Ministry of Education, Chongqing University, Chongqing, 400044, China.
| | - Wensheng Hou
- Key Laboratory of Biorheological Science and Technology of Ministry of Education, Chongqing University, Chongqing, 400044, China.
- Chongqing Medical Electronics Engineering Technology Research Center, Chongqing University, Chongqing 400044, China.
- Chongqing Collaborative Innovation Center for Brain Science, Chongqing University, Chongqing 400044, China.
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9
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Farrell JS, Nguyen QA, Soltesz I. Resolving the Micro-Macro Disconnect to Address Core Features of Seizure Networks. Neuron 2019; 101:1016-1028. [PMID: 30897354 PMCID: PMC6430140 DOI: 10.1016/j.neuron.2019.01.043] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Revised: 12/14/2018] [Accepted: 01/18/2019] [Indexed: 02/07/2023]
Abstract
Current drug treatments for epilepsy attempt to broadly restrict excitability to mask a symptom, seizures, with little regard for the heterogeneous mechanisms that underlie disease manifestation across individuals. Here, we discuss the need for a more complete view of epilepsy, outlining how key features at the cellular and microcircuit level can significantly impact disease mechanisms that are not captured by the most common methodology to study epilepsy, electroencephalography (EEG). We highlight how major advances in neuroscience tool development now enable multi-scale investigation of fundamental questions to resolve the currently controversial understanding of seizure networks. These findings will provide essential insight into what has emerged as a disconnect between the different levels of investigation and identify new targets and treatment options.
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Affiliation(s)
- Jordan S Farrell
- Department of Neurosurgery, Stanford University, Stanford, CA, USA.
| | - Quynh-Anh Nguyen
- Department of Neurosurgery, Stanford University, Stanford, CA, USA
| | - Ivan Soltesz
- Department of Neurosurgery, Stanford University, Stanford, CA, USA.
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10
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An optimized and automated approach to quantifying channelrhodopsin photocurrent kinetics. Anal Biochem 2018; 566:160-167. [PMID: 30502319 DOI: 10.1016/j.ab.2018.11.023] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Revised: 11/23/2018] [Accepted: 11/27/2018] [Indexed: 01/05/2023]
Abstract
Channelrhodopsins are light-activated ion channels that enable targetable activation or inhibition of excitable cells with light. Ion conductance can generally be described by a four step photocycle, which includes two open and two closed states. While a complete understanding of channelrhodopsin function cannot be understood in the absence of kinetic modeling, model fitting requires manual fitting, which is laborious and technically complicated for non-experts. To enhance analysis of photocurrent data, this manuscript describes a fitting program where electrophysiology data can be automatically and quantitatively analyzed. Significant improvement in this program when compared to our previous version includes 1) the ability to automatically find the experiment start time using the derivative of the current signal, 2) utilizing the Object Oriented Programing (OPP) paradigm which is significantly more reliable if the code is used by people with little to no programming experience and 3) the distribution of the code is simplified to sharing a single MATLAB file, including rigorous comments throughout. To demonstrate the utility of this program, we show automated fitting of photocurrents from two member proteins: channelrhodopsin-2 and a chimera between channelrhodopsin-1 and channelrhodopsin-2 (C1C2).
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11
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Camporeze B, Manica BA, Bonafé GA, Ferreira JJC, Diniz AL, de Oliveira CTP, Mathias Junior LR, de Aguiar PHP, Ortega MM. Optogenetics: the new molecular approach to control functions of neural cells in epilepsy, depression and tumors of the central nervous system. Am J Cancer Res 2018; 8:1900-1918. [PMID: 30416844 PMCID: PMC6220144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Accepted: 09/14/2018] [Indexed: 06/09/2023] Open
Abstract
The optogenetic tools have been described as valuable techniques to study neural activity through light stimulation, as well as potential neuromodulator approaches in the management of several central nervous system (CNS) diseases. Since the first bacteriorhodopsin protein described as a single-component light-activated regulator of transmembrane ion flow description, in 1980's, the focus has been on channel proteins for neurobiology; however, the advances in engineering techniques showed involvement changes in cellular biological behavior in several types of proteins involved in cell cytoskeleton regulation, motility and gene expression. Although the use of this technology has been published in many papers, a question still remains regarding real results and potential clinical applicability in CNS diseases, as well as the publications scarcity that systematically analyses the published results. Lastly, the aim of this review is to discuss the experimental results, molecular mechanisms and potential clinical applications of optogenetic tools in epilepsy and depression treatment, as well as its applicability in the treatment of CNS tumors.
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Affiliation(s)
- Bruno Camporeze
- Postgraduate Program in Health Science, Laboratory of Cellular and Molecular Biology and Bioactive Compounds, São Francisco University (USF)Bragança Paulista-SP, Brazil
- Postgraduate Program in Health Science, Department of Neurosurgery, Institute of Medical Assistance of The State Public Servant (IAMSPE)São Paulo-SP, Brazil
| | - Bruno Alcântara Manica
- Departament of Neurology, Medical School University Pontifical University Catholic of São Paulo (PUCSP)Sorocaba-SP, Brazil
| | - Gabriel Alves Bonafé
- Postgraduate Program in Health Science, Laboratory of Cellular and Molecular Biology and Bioactive Compounds, São Francisco University (USF)Bragança Paulista-SP, Brazil
| | | | - Aurélio Lourenço Diniz
- Departament of Neurology, Medical School University Pontifical University Catholic of São Paulo (PUCSP)Sorocaba-SP, Brazil
| | | | | | - Paulo Henrique Pires de Aguiar
- Postgraduate Program in Health Science, Department of Neurosurgery, Institute of Medical Assistance of The State Public Servant (IAMSPE)São Paulo-SP, Brazil
- Departament of Neurology, Medical School University Pontifical University Catholic of São Paulo (PUCSP)Sorocaba-SP, Brazil
- Departament of Neurosurgery, Hospital Santa PaulaSão Paulo-SP, Brazil
- Department of Research and Innovation, Laboratory of Cellular and Molecular Biology, Medical School of ABC (FMABC)Santo André-SP, Brazil
| | - Manoela Marques Ortega
- Postgraduate Program in Health Science, Laboratory of Cellular and Molecular Biology and Bioactive Compounds, São Francisco University (USF)Bragança Paulista-SP, Brazil
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12
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Scott RC, Menendez de la Prida L, Mahoney JM, Kobow K, Sankar R, de Curtis M. WONOEP APPRAISAL: The many facets of epilepsy networks. Epilepsia 2018; 59:1475-1483. [PMID: 30009398 DOI: 10.1111/epi.14503] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/04/2018] [Indexed: 12/20/2022]
Abstract
The brain is a complex system composed of networks of interacting elements, from genes to circuits, whose function (and dysfunction) is not derivable from the superposition of individual components. Epilepsy is frequently described as a network disease, but to date, there is no standardized framework within which network concepts applicable to all levels from genes to whole brain can be used to generate deeper insights into the pathogenesis of seizures or the associated morbidities. To address this shortcoming, the Neurobiology Commission of the International League Against Epilepsy dedicated a Workshop on Neurobiology of Epilepsy (XIV WONOEP 2017) with the aim of formalizing network concepts as they apply to epilepsy and to critically discuss whether and how such concepts could augment current research endeavors. Here, we review concepts and strategies derived by considering epilepsy as a disease of different network hierarchies that range from genes to clinical phenotypes. We propose that the concept of networks is important for understanding epilepsy and is critical for developing new study designs. These approaches could ultimately facilitate the development of novel diagnostic and therapeutic strategies.
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Affiliation(s)
- Rod C Scott
- Department of Neurological Sciences, University of Vermont, Burlington, VT, USA.,Neurology Unit, Great Ormond Street Hospital NHS Trust, London, UK
| | | | - J Matt Mahoney
- Department of Neurological Sciences, University of Vermont, Burlington, VT, USA
| | - Katja Kobow
- Institute of Neuropathology, Universitätsklinikum Erlangen, Erlangen, Germany
| | - Raman Sankar
- Division of Pediatric Neurology, David Geffen School of Medicine and Mattel Children's Hospital UCLA, Los Angeles, CA, USA.,Department of Neurology, David Geffen School of Medicine and Mattel Children's Hospital UCLA, Los Angeles, CA, USA
| | - Marco de Curtis
- Epilepsy Unit, Fondazione IRCCS Carlo Besta Neurological Institute, Milano, Italy
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13
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Christenson Wick Z, Krook-Magnuson E. Specificity, Versatility, and Continual Development: The Power of Optogenetics for Epilepsy Research. Front Cell Neurosci 2018; 12:151. [PMID: 29962936 PMCID: PMC6010559 DOI: 10.3389/fncel.2018.00151] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2018] [Accepted: 05/15/2018] [Indexed: 12/19/2022] Open
Abstract
Optogenetics is a powerful and rapidly expanding set of techniques that use genetically encoded light sensitive proteins such as opsins. Through the selective expression of these exogenous light-sensitive proteins, researchers gain the ability to modulate neuronal activity, intracellular signaling pathways, or gene expression with spatial, directional, temporal, and cell-type specificity. Optogenetics provides a versatile toolbox and has significantly advanced a variety of neuroscience fields. In this review, using recent epilepsy research as a focal point, we highlight how the specificity, versatility, and continual development of new optogenetic related tools advances our understanding of neuronal circuits and neurological disorders. We additionally provide a brief overview of some currently available optogenetic tools including for the selective expression of opsins.
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Affiliation(s)
- Zoé Christenson Wick
- Graduate Program in Neuroscience and Department of Neuroscience, University of Minnesota, Minneapolis, MN, United States
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14
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Acker DWM, Wong I, Kang M, Paradis S. Semaphorin 4D promotes inhibitory synapse formation and suppresses seizures in vivo. Epilepsia 2018; 59:1257-1268. [PMID: 29799628 DOI: 10.1111/epi.14429] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/19/2018] [Indexed: 02/02/2023]
Abstract
OBJECTIVE We previously discovered a role for the extracellular domain of the transmembrane protein semaphorin 4D (Sema4D) as a fast-acting, selective, and positive regulator of functional γ-aminobutyric acid (GABA)ergic synapse formation in hippocampal neuronal culture. We also demonstrated that Sema4D treatment increases inhibitory tone and suppresses hyperexcitability in an organotypic hippocampal slice culture model of epilepsy. Here, we investigate the ability of Sema4D to promote GABAergic synapse formation and suppress seizure activity in vivo in adult mice. METHODS We performed a 3-hour, intrahippocampal infusion of Sema4D or control protein into the CA1 region of adult mice. To quantify GABAergic presynaptic bouton density, we performed immunohistochemistry on hippocampal tissue sections isolated from these animals using an antibody that specifically recognizes the glutamic acid decarboxylase isoform 65 protein (GAD65), which is localized to presynaptic GABAergic boutons. To assess seizure activity, we employed 2 in vivo mouse models of epilepsy, intravenous (iv) pentylenetetrazol (PTZ) and hippocampal electrical kindling, in the presence or absence of Sema4D treatment. We monitored seizure activity by behavioral observation or electroencephalography (EEG). To assay the persistence of the Sema4D effect, we monitored seizure activity and measured the density of GAD65-positive presynaptic boutons 3 or 48 hours after Sema4D infusion. RESULTS Sema4D-treated mice displayed an elevated density of GABAergic presynaptic boutons juxtaposed to hippocampal pyramidal neuron cell bodies, consistent with the hypothesis that Sema4D promotes the formation of new inhibitory synapses in vivo. In addition, Sema4D acutely suppressed seizures in both the PTZ and electrical kindling models. When we introduced a 48-hour gap between Sema4D treatment and the seizure stimulus, seizure activity was indistinguishable from controls. Moreover, immunohistochemistry on brain sections or hippocampal slices isolated 3 hours, but not 48 hours, after Sema4D treatment displayed an increase in GABAergic bouton density, demonstrating temporal correlation between the effects of Sema4D on seizures and GABAergic synaptic components. SIGNIFICANCE Our findings suggest a novel approach to treating acute seizures: harnessing synaptogenic molecules to enhance connectivity in the inhibitory network.
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Affiliation(s)
- Daniel W M Acker
- Department of Biology, National Center for Behavioral Genomics, Brandeis University, Waltham, MA, USA
| | - Irene Wong
- Department of Biology, National Center for Behavioral Genomics, Brandeis University, Waltham, MA, USA
| | - Mihwa Kang
- Department of Biology, National Center for Behavioral Genomics, Brandeis University, Waltham, MA, USA
| | - Suzanne Paradis
- Department of Biology, National Center for Behavioral Genomics, Brandeis University, Waltham, MA, USA
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Altered Chloride Homeostasis Decreases the Action Potential Threshold and Increases Hyperexcitability in Hippocampal Neurons. eNeuro 2018; 4:eN-NWR-0172-17. [PMID: 29379872 PMCID: PMC5783240 DOI: 10.1523/eneuro.0172-17.2017] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Revised: 10/09/2017] [Accepted: 10/31/2017] [Indexed: 11/21/2022] Open
Abstract
Chloride ions play an important role in controlling excitability of principal neurons in the central nervous system. When neurotransmitter GABA is released from inhibitory interneurons, activated GABA type A (GABAA) receptors on principal neurons become permeable to chloride. Typically, chloride flows through activated GABAA receptors into the neurons causing hyperpolarization or shunting inhibition, and in turn inhibits action potential (AP) generation. However, in situations when intracellular chloride concentration is increased, chloride ions can flow in opposite direction, depolarize neurons, and promote AP generation. It is generally recognized that altered chloride homeostasis per se has no effect on the AP threshold. Here, we demonstrate that chloride overload of mouse principal CA3 pyramidal neurons not only makes these cells more excitable through GABAA receptor activation but also lowers the AP threshold, further aggravating excitability. This phenomenon has not been described in principal neurons and adds to our understanding of mechanisms regulating neuronal and network excitability, particularly in developing brain and during pathological situations with altered chloride homeostasis. This finding further broadens the spectrum of neuronal plasticity regulated by ionic compositions across the cellular membrane.
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Krook-Magnuson E. Illuminating seizures: optogenetic approaches to studying networks in epilepsy. J Neurosci Res 2017; 95:2323-2324. [PMID: 28836289 DOI: 10.1002/jnr.24147] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Accepted: 08/09/2017] [Indexed: 11/07/2022]
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17
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Forcelli PA. Applications of optogenetic and chemogenetic methods to seizure circuits: Where to go next? J Neurosci Res 2017; 95:2345-2356. [PMID: 28791729 DOI: 10.1002/jnr.24135] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2017] [Revised: 07/05/2017] [Accepted: 07/14/2017] [Indexed: 01/02/2023]
Abstract
Epilepsy is the quintessential circuit disorder, with seizure activity propagating through anatomically constrained pathways. These pathways, necessary for normal sensory, motor, and cognitive function, are hijacked during seizures. Understanding the network architecture at the level of both local microcircuits and distributed macrocircuits may provide new therapeutic avenues for the treatment of epilepsy. Over the past decade, optogenetic and chemogenetic tools have enabled previously impossible levels of functional circuit mapping in neuroscience. In this review, examples of the application of optogenetics and chemogenetics to epilepsy are raised, the comparative strengths and weaknesses of these approaches are discussed for both preclinical and translational applications, and recent applications of these approaches in other areas of neuroscience are highlighted. These points are raised in an effort to highlight the potential of these methods to address additional unanswered questions in epilepsy.
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Affiliation(s)
- Patrick A Forcelli
- Department of Pharmacology & Physiology, Department of Neuroscience, and Interdisciplinary Program in Neuroscience, Georgetown University School of Medicine, Washington, DC
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