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Ewens AN, Pilski A, Hastings SD, Krook-Magnuson C, Graves SM, Krook-Magnuson E, Thayer SA. Levetiracetam Prevents Neurophysiological Changes and Preserves Cognitive Function in the Human Immunodeficiency Virus (HIV)-1 Transactivator of Transcription Transgenic Mouse Model of HIV-Associated Neurocognitive Disorder. J Pharmacol Exp Ther 2024; 391:104-118. [PMID: 39060163 DOI: 10.1124/jpet.124.002272] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2024] [Revised: 06/24/2024] [Accepted: 07/22/2024] [Indexed: 07/28/2024] Open
Abstract
Human immunodeficiency virus (HIV)-associated neurocognitive disorder (HAND) affects nearly half of the 39 million people living with HIV. HAND symptoms range from subclinical cognitive impairment to dementia; the mechanisms that underlie HAND remain unclear and there is no treatment. The HIV protein transactivator of transcription (TAT) is thought to contribute to HAND because it persists in the central nervous system and elicits neurotoxicity in animal models. Network hyperexcitability is associated with accelerated cognitive decline in neurodegenerative disorders. Here we show that the antiepileptic drug levetiracetam (LEV) attenuated aberrant excitatory synaptic transmission, protected synaptic plasticity, reduced seizure susceptibility, and preserved cognition in inducible TAT (iTAT) transgenic male mice. iTAT mice had an increased frequency of spontaneous excitatory postsynaptic currents in hippocampal slice recordings and impaired long-term potentiation, a form of synaptic plasticity that underlies learning and memory. Two-week administration of LEV by osmotic minipump prevented both impairments. Kainic acid administered to iTAT mice induced a higher maximum behavioral seizure score, longer seizure duration, and shorter latency to first seizure, consistent with a lower seizure threshold. LEV treatment prevented these in vivo signs of hyperexcitability. Lastly, in the Barnes maze, iTAT mice required more time to reach the goal, committed more errors, and received lower cognitive scores relative to iTAT mice treated with LEV. Thus, TAT expression drives functional deficits, suggesting a causative role in HAND. As LEV not only prevented aberrant synaptic activity in iTAT mice but also prevented cognitive dysfunction, it may provide a promising pharmacological approach to the treatment of HAND. SIGNIFICANCE STATEMENT: Approximately half of people living with human immunodeficiency virus (HIV) also suffer from HIV-associated neurocognitive disorder (HAND), for which there is no treatment. The HIV protein transactivator of transcription (TAT) causes toxicity that is thought to contribute to HAND. Here, the antiepileptic drug levetiracetam (LEV) prevented synaptic and cognitive impairments in a TAT-expressing mouse. LEV is widely used to treat seizures and is well-tolerated in humans, including those with HIV. This study supports further investigation of LEV-mediated neuroprotection in HAND.
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Affiliation(s)
- Ashley N Ewens
- Department of Pharmacology, University of Minnesota Medical School, Minneapolis, Minnesota (A.N.E., A.P., S.M.G., S.A.T.); and Department of Neuroscience, University of Minnesota, Minneapolis, Minnesota (S.D.H., C.K.-M., E.K.-M.)
| | - Alexander Pilski
- Department of Pharmacology, University of Minnesota Medical School, Minneapolis, Minnesota (A.N.E., A.P., S.M.G., S.A.T.); and Department of Neuroscience, University of Minnesota, Minneapolis, Minnesota (S.D.H., C.K.-M., E.K.-M.)
| | - Shayne D Hastings
- Department of Pharmacology, University of Minnesota Medical School, Minneapolis, Minnesota (A.N.E., A.P., S.M.G., S.A.T.); and Department of Neuroscience, University of Minnesota, Minneapolis, Minnesota (S.D.H., C.K.-M., E.K.-M.)
| | - Chris Krook-Magnuson
- Department of Pharmacology, University of Minnesota Medical School, Minneapolis, Minnesota (A.N.E., A.P., S.M.G., S.A.T.); and Department of Neuroscience, University of Minnesota, Minneapolis, Minnesota (S.D.H., C.K.-M., E.K.-M.)
| | - Steven M Graves
- Department of Pharmacology, University of Minnesota Medical School, Minneapolis, Minnesota (A.N.E., A.P., S.M.G., S.A.T.); and Department of Neuroscience, University of Minnesota, Minneapolis, Minnesota (S.D.H., C.K.-M., E.K.-M.)
| | - Esther Krook-Magnuson
- Department of Pharmacology, University of Minnesota Medical School, Minneapolis, Minnesota (A.N.E., A.P., S.M.G., S.A.T.); and Department of Neuroscience, University of Minnesota, Minneapolis, Minnesota (S.D.H., C.K.-M., E.K.-M.)
| | - Stanley A Thayer
- Department of Pharmacology, University of Minnesota Medical School, Minneapolis, Minnesota (A.N.E., A.P., S.M.G., S.A.T.); and Department of Neuroscience, University of Minnesota, Minneapolis, Minnesota (S.D.H., C.K.-M., E.K.-M.)
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Jain S, LaFrancois JJ, Gerencer K, Botterill JJ, Kennedy M, Criscuolo C, Scharfman HE. Increasing adult-born neurons protects mice from epilepsy. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.07.08.548217. [PMID: 37502909 PMCID: PMC10369878 DOI: 10.1101/2023.07.08.548217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/29/2023]
Abstract
Neurogenesis occurs in the adult brain in the hippocampal dentate gyrus, an area that contains neurons which are vulnerable to insults and injury, such as severe seizures. Previous studies showed that increasing adult neurogenesis reduced neuronal damage after these seizures. Because the damage typically is followed by chronic life-long seizures (epilepsy), we asked if increasing adult-born neurons would prevent epilepsy. Adult-born neurons were selectively increased by deleting the pro-apoptotic gene Bax from Nestin-expressing progenitors. Tamoxifen was administered at 6 weeks of age to conditionally delete Bax in Nestin-CreER T2 Bax fl/fl mice. Six weeks after tamoxifen administration, severe seizures (status epilepticus; SE) were induced by injection of the convulsant pilocarpine. After mice developed epilepsy, seizure frequency was quantified for 3 weeks. Mice with increased adult-born neurons exhibited fewer chronic seizures. Postictal depression was reduced also. These results were primarily in female mice, possibly because they were the more affected by Bax deletion than males, consistent with sex differences in Bax . The female mice with enhanced adult-born neurons also showed less neuronal loss of hilar mossy cells and hilar somatostatin-expressing neurons than wild type females or males, which is notable because these two hilar cell types are implicated in epileptogenesis. The results suggest that selective Bax deletion to increase adult-born neurons can reduce experimental epilepsy, and the effect shows a striking sex difference. The results are surprising in light of past studies showing that suppressing adult-born neurons can also reduce chronic seizures.
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Cattaneo S, Bettegazzi B, Crippa L, Asth L, Regoni M, Soukupova M, Zucchini S, Cantore A, Codazzi F, Valtorta F, Simonato M. Gene therapy for epilepsy targeting neuropeptide Y and its Y2 receptor to dentate gyrus granule cells. EMBO Rep 2024:10.1038/s44319-024-00244-0. [PMID: 39251828 DOI: 10.1038/s44319-024-00244-0] [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: 12/20/2023] [Revised: 08/15/2024] [Accepted: 08/22/2024] [Indexed: 09/11/2024] Open
Abstract
Gene therapy is emerging as an alternative option for individuals with drug-resistant focal epilepsy. Here, we explore the potential of a novel gene therapy based on Neuropeptide Y (NPY), a well-known endogenous anticonvulsant. We develop a lentiviral vector co-expressing NPY with its inhibitory receptor Y2 in which, for the first time, both transgenes are placed under the control of the minimal CamKIIa(0.4) promoter, biasing expression toward excitatory neurons and allowing autoregulation of neuronal excitability by Y2 receptor-mediated inhibition. Vector-induced NPY and Y2 expression and safety are first assessed in cultures of hippocampal neurons. In vivo experiments demonstrate efficient and nearly selective overexpression of both genes in granule cell mossy fiber terminals following vector administration in the dentate gyrus. Telemetry video-EEG monitoring reveals a reduction in the frequency and duration of seizures in the synapsin triple KO model. This study shows that targeting a small subset of neurons (hippocampal granule cells) with a combined overexpression of NPY and Y2 receptor is sufficient to reduce the occurrence of spontaneous seizures.
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Affiliation(s)
- Stefano Cattaneo
- Vita-Salute San Raffaele University, 20132, Milan, Italy
- Division of Neuroscience, IRCCS San Raffaele Scientific Institute, 20132, Milan, Italy
| | - Barbara Bettegazzi
- Vita-Salute San Raffaele University, 20132, Milan, Italy
- Division of Neuroscience, IRCCS San Raffaele Scientific Institute, 20132, Milan, Italy
| | - Lucia Crippa
- Vita-Salute San Raffaele University, 20132, Milan, Italy
- Division of Neuroscience, IRCCS San Raffaele Scientific Institute, 20132, Milan, Italy
| | - Laila Asth
- Department of Neuroscience and Rehabilitation, University of Ferrara, 44121, Ferrara, Italy
| | - Maria Regoni
- Vita-Salute San Raffaele University, 20132, Milan, Italy
- Division of Neuroscience, IRCCS San Raffaele Scientific Institute, 20132, Milan, Italy
| | - Marie Soukupova
- Department of Neuroscience and Rehabilitation, University of Ferrara, 44121, Ferrara, Italy
| | - Silvia Zucchini
- Department of Neuroscience and Rehabilitation, University of Ferrara, 44121, Ferrara, Italy
| | - Alessio Cantore
- Vita-Salute San Raffaele University, 20132, Milan, Italy
- San Raffaele Telethon Institute for Gene Therapy, IRCCS San Raffaele Scientific Institute, 20123, Milan, Italy
| | - Franca Codazzi
- Vita-Salute San Raffaele University, 20132, Milan, Italy
- Division of Neuroscience, IRCCS San Raffaele Scientific Institute, 20132, Milan, Italy
| | - Flavia Valtorta
- Vita-Salute San Raffaele University, 20132, Milan, Italy
- Division of Neuroscience, IRCCS San Raffaele Scientific Institute, 20132, Milan, Italy
| | - Michele Simonato
- Division of Neuroscience, IRCCS San Raffaele Scientific Institute, 20132, Milan, Italy.
- Department of Neuroscience and Rehabilitation, University of Ferrara, 44121, Ferrara, Italy.
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Schwaderlapp N, Paschen E, LeVan P, von Elverfeldt D, Haas CA. Probing hippocampal stimulation in experimental temporal lobe epilepsy with functional MRI. FRONTIERS IN NEUROIMAGING 2024; 3:1423770. [PMID: 39205946 PMCID: PMC11349577 DOI: 10.3389/fnimg.2024.1423770] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/26/2024] [Accepted: 07/29/2024] [Indexed: 09/04/2024]
Abstract
Electrical neurostimulation is currently used to manage epilepsy, but the most effective approach for minimizing seizure occurrence is uncertain. While functional MRI (fMRI) can reveal which brain areas are affected by stimulation, simultaneous deep brain stimulation (DBS)-fMRI examinations in patients are rare and the possibility to investigate multiple stimulation protocols is limited. In this study, we utilized the intrahippocampal kainate mouse model of mesial temporal lobe epilepsy (mTLE) to systematically examine the brain-wide responses to electrical stimulation using fMRI. We compared fMRI responses of saline-injected controls and epileptic mice during stimulation in the septal hippocampus (HC) at 10 Hz and demonstrated the effects of different stimulation amplitudes (80-230 μA) and frequencies (1-100 Hz) in epileptic mice. Motivated by recent studies exploring 1 Hz stimulation to prevent epileptic seizures, we furthermore investigated the effect of prolonged 1 Hz stimulation with fMRI. Compared to sham controls, epileptic mice showed less propagation to the contralateral HC, but significantly stronger responses in the ipsilateral HC and a wider spread to the entorhinal cortex and septal region. Varying the stimulation amplitude had little effect on the resulting activation patterns, whereas the stimulation frequency represented the key parameter and determined whether the induced activation remained local or spread from the hippocampal formation into cortical areas. Prolonged stimulation of epileptic mice at 1 Hz caused a slight reduction in local excitability. In this way, our study contributes to a better understanding of these stimulation paradigms.
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Affiliation(s)
- Niels Schwaderlapp
- Division of Medical Physics, Department of Diagnostic and Interventional Radiology, Faculty of Medicine, University Medical Center Freiburg, University of Freiburg, Freiburg im Breisgau, Germany
- BrainLinks-BrainTools Center, University of Freiburg, Freiburg im Breisgau, Germany
| | - Enya Paschen
- Experimental Epilepsy Research, Department of Neurosurgery, Faculty of Medicine, Medical Center - University of Freiburg, University of Freiburg, Freiburg im Breisgau, Germany
| | - Pierre LeVan
- Department of Radiology and Paediatrics, Cumming School of Medicine, Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada
| | - Dominik von Elverfeldt
- Division of Medical Physics, Department of Diagnostic and Interventional Radiology, Faculty of Medicine, University Medical Center Freiburg, University of Freiburg, Freiburg im Breisgau, Germany
| | - Carola A. Haas
- BrainLinks-BrainTools Center, University of Freiburg, Freiburg im Breisgau, Germany
- Experimental Epilepsy Research, Department of Neurosurgery, Faculty of Medicine, Medical Center - University of Freiburg, University of Freiburg, Freiburg im Breisgau, Germany
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Olorocisimo JP, Ohta Y, Regonia PR, Castillo VCG, Yoshimoto J, Takehara H, Sasagawa K, Ohta J. Brain-implantable needle-type CMOS imaging device enables multi-layer dissection of seizure calcium dynamics in the hippocampus. J Neural Eng 2024; 21:046022. [PMID: 38925109 DOI: 10.1088/1741-2552/ad5c03] [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: 01/15/2024] [Accepted: 06/26/2024] [Indexed: 06/28/2024]
Abstract
Objective: Current neuronal imaging methods mostly use bulky lenses that either impede animal behavior or prohibit multi-depth imaging. To overcome these limitations, we developed a lightweight lensless biophotonic system for neuronal imaging, enabling compact and simultaneous visualization of multiple brain layers.Approach: Our developed 'CIS-NAIST' device integrates a micro-CMOS image sensor, thin-film fluorescence filter, micro-LEDs, and a needle-shaped flexible printed circuit. With this device, we monitored neuronal calcium dynamics during seizures across the different layers of the hippocampus and employed machine learning techniques for seizure classification and prediction.Main results: The CIS-NAIST device revealed distinct calcium activity patterns across the CA1, molecular interlayer, and dentate gyrus. Our findings indicated an elevated calcium amplitude activity specifically in the dentate gyrus compared to other layers. Then, leveraging the multi-layer data obtained from the device, we successfully classified seizure calcium activity and predicted seizure behavior using Long Short-Term Memory and Hidden Markov models.Significance: Taken together, our 'CIS-NAIST' device offers an effective and minimally invasive method of seizure monitoring that can help elucidate the mechanisms of temporal lobe epilepsy.
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Affiliation(s)
| | - Yasumi Ohta
- Division of Materials Science, Nara Institute of Science and Technology, Ikoma, Japan
| | - Paul R Regonia
- Department of Computer Science, University of the Philippines Diliman, Manila, The Philippines
| | - Virgil C G Castillo
- Division of Materials Science, Nara Institute of Science and Technology, Ikoma, Japan
| | - Junichiro Yoshimoto
- Department of Biomedical Data Science, Fujita Health University School of Medicine, Toyoake, Japan
| | - Hironari Takehara
- Division of Materials Science, Nara Institute of Science and Technology, Ikoma, Japan
| | - Kiyotaka Sasagawa
- Division of Materials Science, Nara Institute of Science and Technology, Ikoma, Japan
| | - Jun Ohta
- Division of Materials Science, Nara Institute of Science and Technology, Ikoma, Japan
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6
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Guo D, Han L, Godale CM, Rensing NR, Danzer SC, Wong M. A role of dentate gyrus mechanistic target of rapamycin activation in epileptogenesis in a mouse model of posttraumatic epilepsy. Epilepsia 2024; 65:2127-2137. [PMID: 38761065 PMCID: PMC11251851 DOI: 10.1111/epi.18011] [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: 01/28/2024] [Revised: 04/30/2024] [Accepted: 04/30/2024] [Indexed: 05/20/2024]
Abstract
OBJECTIVE The mechanistic target of rapamycin (mTOR) pathway has been implicated in promoting epileptogenesis in animal models of acquired epilepsy, such as posttraumatic epilepsy (PTE) following traumatic brain injury (TBI). However, the specific anatomical regions and neuronal populations mediating mTOR's role in epileptogenesis are not well defined. In this study, we tested the hypothesis that mTOR activation in dentate gyrus granule cells promotes neuronal death, mossy fiber sprouting, and PTE in the controlled cortical impact (CCI) model of TBI. METHODS An adeno-associated virus (AAV)-Cre viral vector was injected into the hippocampus of Rptorflox/flox (regulatory-associated protein of mTOR) mutant mice to inhibit mTOR activation in dentate gyrus granule cells. Four weeks after AAV-Cre or AAV-vehicle injection, mice underwent CCI injury and were subsequently assessed for mTOR pathway activation by Western blotting, neuronal death, and mossy fiber sprouting by immunopathological analysis, and posttraumatic seizures by video-electroencephalographic monitoring. RESULTS AAV-Cre injection primarily affected the dentate gyrus and inhibited hippocampal mTOR activation following CCI injury. AAV-Cre-injected mice had reduced neuronal death in dentate gyrus detected by Fluoro-Jade B staining and decreased mossy fiber sprouting by ZnT3 immunostaining. Finally, AAV-Cre-injected mice exhibited a decrease in incidence of PTE. SIGNIFICANCE mTOR pathway activation in dentate gyrus granule cells may at least partly mediate pathological abnormalities and epileptogenesis in models of TBI and PTE. Targeted modulation of mTOR activity in this hippocampal network may represent a focused therapeutic approach for antiepileptogenesis and prevention of PTE.
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Affiliation(s)
- Dongjun Guo
- Department of Neurology and the Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, MO, USA 63110
| | - Lirong Han
- Department of Neurology and the Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, MO, USA 63110
| | - Christin M. Godale
- Department of Anesthesia, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH 45229
| | - Nicholas R. Rensing
- Department of Neurology and the Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, MO, USA 63110
| | - Steve C. Danzer
- Department of Anesthesia, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH 45229
| | - Michael Wong
- Department of Neurology and the Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, MO, USA 63110
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Giansante G, Mazzoleni S, Zippo AG, Ponzoni L, Ghilardi A, Maiellano G, Lewerissa E, van Hugte E, Nadif Kasri N, Francolini M, Sala M, Murru L, Bassani S, Passafaro M. Neuronal network activity and connectivity are impaired in a conditional knockout mouse model with PCDH19 mosaic expression. Mol Psychiatry 2024; 29:1710-1725. [PMID: 36997609 PMCID: PMC11371655 DOI: 10.1038/s41380-023-02022-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Revised: 02/24/2023] [Accepted: 02/28/2023] [Indexed: 04/01/2023]
Abstract
Mutations in PCDH19 gene, which encodes protocadherin-19 (PCDH19), cause Developmental and Epileptic Encephalopathy 9 (DEE9). Heterogeneous loss of PCDH19 expression in neurons is considered a key determinant of the disorder; however, how PCDH19 mosaic expression affects neuronal network activity and circuits is largely unclear. Here, we show that the hippocampus of Pcdh19 mosaic mice is characterized by structural and functional synaptic defects and by the presence of PCDH19-negative hyperexcitable neurons. Furthermore, global reduction of network firing rate and increased neuronal synchronization have been observed in different limbic system areas. Finally, network activity analysis in freely behaving mice revealed a decrease in excitatory/inhibitory ratio and functional hyperconnectivity within the limbic system of Pcdh19 mosaic mice. Altogether, these results indicate that altered PCDH19 expression profoundly affects circuit wiring and functioning, and provide new key to interpret DEE9 pathogenesis.
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Affiliation(s)
| | - Sara Mazzoleni
- Institute of Neuroscience, CNR, 20854, Vedano al Lambro, Italy
- Department of Medical Biotechnology and Translational Medicine, Università degli Studi di Milano, 20129, Milano, Italy
| | - Antonio G Zippo
- Institute of Neuroscience, CNR, 20854, Vedano al Lambro, Italy
- NeuroMI Milan Center for Neuroscience, University of Milano-Bicocca, 20126, Milano, Italy
| | - Luisa Ponzoni
- Institute of Neuroscience, CNR, 20854, Vedano al Lambro, Italy
| | - Anna Ghilardi
- Department of Medical Biotechnology and Translational Medicine, Università degli Studi di Milano, 20129, Milano, Italy
| | - Greta Maiellano
- Department of Medical Biotechnology and Translational Medicine, Università degli Studi di Milano, 20129, Milano, Italy
| | - Elly Lewerissa
- Radboud University Nijmegen Medical Centre, Donders Institute for Brain, Cognition, and Behaviour, Department of Human Genetics, Department of Human Genetics Cognitive Neuroscience, Nijmegen, Netherlands
| | - Eline van Hugte
- Radboud University Nijmegen Medical Centre, Donders Institute for Brain, Cognition, and Behaviour, Department of Human Genetics, Department of Human Genetics Cognitive Neuroscience, Nijmegen, Netherlands
| | - Nael Nadif Kasri
- Radboud University Nijmegen Medical Centre, Donders Institute for Brain, Cognition, and Behaviour, Department of Human Genetics, Department of Human Genetics Cognitive Neuroscience, Nijmegen, Netherlands
| | - Maura Francolini
- Department of Medical Biotechnology and Translational Medicine, Università degli Studi di Milano, 20129, Milano, Italy
| | | | - Luca Murru
- Institute of Neuroscience, CNR, 20854, Vedano al Lambro, Italy
- NeuroMI Milan Center for Neuroscience, University of Milano-Bicocca, 20126, Milano, Italy
| | - Silvia Bassani
- Institute of Neuroscience, CNR, 20854, Vedano al Lambro, Italy.
- NeuroMI Milan Center for Neuroscience, University of Milano-Bicocca, 20126, Milano, Italy.
| | - Maria Passafaro
- Institute of Neuroscience, CNR, 20854, Vedano al Lambro, Italy.
- NeuroMI Milan Center for Neuroscience, University of Milano-Bicocca, 20126, Milano, Italy.
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Stephens GS, Park J, Eagle A, You J, Silva-Pérez M, Fu CH, Choi S, Romain CPS, Sugimoto C, Buffington SA, Zheng Y, Costa-Mattioli M, Liu Y, Robison AJ, Chin J. Persistent ∆FosB expression limits recurrent seizure activity and provides neuroprotection in the dentate gyrus of APP mice. Prog Neurobiol 2024; 237:102612. [PMID: 38642602 PMCID: PMC11406539 DOI: 10.1016/j.pneurobio.2024.102612] [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: 04/03/2023] [Revised: 03/14/2024] [Accepted: 04/12/2024] [Indexed: 04/22/2024]
Abstract
Recurrent seizures lead to accumulation of the activity-dependent transcription factor ∆FosB in hippocampal dentate granule cells in both mouse models of epilepsy and mouse models of Alzheimer's disease (AD), which is also associated with increased incidence of seizures. In patients with AD and related mouse models, the degree of ∆FosB accumulation corresponds with increasing severity of cognitive deficits. We previously found that ∆FosB impairs spatial memory in mice by epigenetically regulating expression of target genes such as calbindin that are involved in synaptic plasticity. However, the suppression of calbindin in conditions of neuronal hyperexcitability has been demonstrated to provide neuroprotection to dentate granule cells, indicating that ∆FosB may act over long timescales to coordinate neuroprotective pathways. To test this hypothesis, we used viral-mediated expression of ∆JunD to interfere with ∆FosB signaling over the course of several months in transgenic mice expressing mutant human amyloid precursor protein (APP), which exhibit spontaneous seizures and develop AD-related neuropathology and cognitive deficits. Our results demonstrate that persistent ∆FosB activity acts through discrete modes of hippocampal target gene regulation to modulate neuronal excitability, limit recurrent seizure activity, and provide neuroprotection to hippocampal dentate granule cells in APP mice.
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Affiliation(s)
| | - Jin Park
- Department of Neuroscience, Baylor College of Medicine, USA
| | - Andrew Eagle
- Department of Physiology, Michigan State University, USA
| | - Jason You
- Department of Neuroscience, Baylor College of Medicine, USA
| | | | - Chia-Hsuan Fu
- Department of Neuroscience, Baylor College of Medicine, USA
| | - Sumin Choi
- Department of Neuroscience, Baylor College of Medicine, USA
| | | | - Chiho Sugimoto
- Department of Physiology, Michigan State University, USA
| | - Shelly A Buffington
- Center for Precision Environmental Health, Department of Neuroscience, Baylor College of Medicine, USA
| | - Yi Zheng
- Department of Neuroscience, Baylor College of Medicine, USA
| | | | - Yin Liu
- Department of Neurobiology and Anatomy, McGovern Medical School at UT Health, USA
| | - A J Robison
- Department of Physiology, Michigan State University, USA
| | - Jeannie Chin
- Department of Neuroscience, Baylor College of Medicine, USA.
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9
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Danis AB, Gallagher AA, Anderson AN, Isakharov A, Beeson KA, Schnell E. Altered Hippocampal Activation in Seizure-Prone CACNA2D2 Knock-out Mice. eNeuro 2024; 11:ENEURO.0486-23.2024. [PMID: 38749701 PMCID: PMC11097259 DOI: 10.1523/eneuro.0486-23.2024] [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: 11/21/2023] [Revised: 04/08/2024] [Accepted: 04/10/2024] [Indexed: 05/18/2024] Open
Abstract
The voltage-gated calcium channel subunit α2δ-2 controls calcium-dependent signaling in neurons, and loss of this subunit causes epilepsy in both mice and humans. To determine whether mice without α2δ-2 demonstrate hippocampal activation or histopathological changes associated with seizure activity, we measured expression of the activity-dependent gene c-fos and various histopathological correlates of temporal lobe epilepsy (TLE) in hippocampal tissue from wild-type (WT) and α2δ-2 knock-out (CACNA2D2 KO) mice using immunohistochemical staining and confocal microscopy. Both genotypes demonstrated similarly sparse c-fos and ΔFosB expressions within the hippocampal dentate granule cell layer (GCL) at baseline, consistent with no difference in basal activity of granule cells between genotypes. Surprisingly, when mice were assayed 1 h after handling-associated convulsions, KO mice had fewer c-fos-positive cells but dramatically increased ΔFosB expression in the dentate gyrus compared with WT mice. After administration of a subthreshold pentylenetetrazol dose, however, KO mice dentate had significantly more c-fos expression compared with WT mice. Other histopathological markers of TLE in these mice, including markers of neurogenesis, glial activation, and mossy fiber sprouting, were similar between WT and KO mice, apart from a small but statistically significant increase in hilar mossy cell density, opposite to what is typically found in mice with TLE. This suggests that the differences in seizure-associated dentate gyrus function in the absence of α2δ-2 protein are likely due to altered functional properties of the network without associated structural changes in the hippocampus at the typical age of seizure onset.
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Affiliation(s)
- Alyssa B Danis
- Department of Anesthesiology and Perioperative Medicine, Oregon Health & Science University, Portland, Oregon 97239
- Research and Development Service, Portland VA Health Care System, Portland, Oregon 97239
| | - Ashlynn A Gallagher
- Department of Anesthesiology and Perioperative Medicine, Oregon Health & Science University, Portland, Oregon 97239
- Research and Development Service, Portland VA Health Care System, Portland, Oregon 97239
| | - Ashley N Anderson
- Department of Anesthesiology and Perioperative Medicine, Oregon Health & Science University, Portland, Oregon 97239
- Research and Development Service, Portland VA Health Care System, Portland, Oregon 97239
| | - Arielle Isakharov
- Neuroscience Graduate Program, Oregon Health & Science University, Portland, Oregon 97239
| | - Kathleen A Beeson
- Neuroscience Graduate Program, Oregon Health & Science University, Portland, Oregon 97239
| | - Eric Schnell
- Department of Anesthesiology and Perioperative Medicine, Oregon Health & Science University, Portland, Oregon 97239
- Research and Development Service, Portland VA Health Care System, Portland, Oregon 97239
- Neuroscience Graduate Program, Oregon Health & Science University, Portland, Oregon 97239
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10
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Aleksandrova EP, Ivlev AP, Kulikov AA, Naumova AA, Glazova MV, Chernigovskaya EV. Audiogenic kindling activates glutamatergic system in the hippocampus of rats with genetic predisposition to audiogenic seizures. Brain Res 2024; 1829:148792. [PMID: 38325559 DOI: 10.1016/j.brainres.2024.148792] [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: 10/02/2023] [Revised: 01/22/2024] [Accepted: 01/28/2024] [Indexed: 02/09/2024]
Abstract
Temporal lobe epilepsy (TLE) development is associated with dysregulation of glutamatergic transmission in the hippocampus; however, detailed molecular mechanisms of pathological changes are still poorly understood. In the present study, we performed the complex analysis of glutamatergic system in the hippocampus of Krushinsky-Molodkina (KM) rats genetically prone to audiogenic seizures (AGS). Daily AGS stimulations (audiogenic kindling) were used to reproduce the dynamics of TLE development. Naïve KM rats were used as a control. After 14 AGS, at the stage of developing TLE, KM rats demonstrated significant upregulation of extracellular signal-regulated kinases (ERK) 1 and 2, cAMP response element-binding protein (CREB), and c-Fos in the hippocampus indicating activation of the hippocampal cells. These changes were accompanied with an increase in glutaminase and vesicular glutamate transporter (VGLUT) 2 suggesting the activation of glutamate production and loading into the synaptic vesicles. After 21 AGS, when TLE was fully-established, alterations were similar but more pronounced, with higher activation of glutaminase, increase in glutamate production, upregulation of VGLUT1 and 2, and Fos-related antigen 1 (Fra-1) along with c-Fos. Analysis of glutamate receptors showed variable changes. Thus, after 14 AGS, simultaneous increase in metabotropic glutamate receptor mGluR1 and decrease in ionotropic N-methyl-D-aspartate (NMDA) receptors could reflect compensatory anti-epileptic mechanism, while further kindling progression induced upregulation of ionotropic receptors, probably, contributing to the hippocampal epileptization. However, we revealed practically no alterations in the expression of synaptic proteins. Altogether, obtained results suggested that overactivation of glutamate production in the hippocampus strongly contributed to TLE development in KM rats.
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Affiliation(s)
- Ekaterina P Aleksandrova
- Sechenov Institute of Evolutionary Physiology and Biochemistry, The Russian Academy of Sciences, St. Petersburg, Russia
| | - Andrey P Ivlev
- Sechenov Institute of Evolutionary Physiology and Biochemistry, The Russian Academy of Sciences, St. Petersburg, Russia
| | - Alexey A Kulikov
- Sechenov Institute of Evolutionary Physiology and Biochemistry, The Russian Academy of Sciences, St. Petersburg, Russia
| | - Alexandra A Naumova
- Sechenov Institute of Evolutionary Physiology and Biochemistry, The Russian Academy of Sciences, St. Petersburg, Russia
| | - Margarita V Glazova
- Sechenov Institute of Evolutionary Physiology and Biochemistry, The Russian Academy of Sciences, St. Petersburg, Russia.
| | - Elena V Chernigovskaya
- Sechenov Institute of Evolutionary Physiology and Biochemistry, The Russian Academy of Sciences, St. Petersburg, Russia
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11
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Teng S, Wang W, Wen JJJ, Wang J, Turi GF, Peng Y. Expression of GCaMP6s in the dentate gyrus induces tonic-clonic seizures. Sci Rep 2024; 14:8104. [PMID: 38582752 PMCID: PMC10998915 DOI: 10.1038/s41598-024-58819-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2023] [Accepted: 04/03/2024] [Indexed: 04/08/2024] Open
Abstract
GCaMP is a genetically encoded calcium indicator (GECI) widely used in neuroscience research. It measures intracellular Ca2+ level by fluorescence changes as it directly binds to Ca2+. In this process, the effect of this calcium buffer on the intracellular calcium signaling and cell physiology is often not taken into consideration. However, growing evidence from calcium imaging studies shows GCaMP expression under certain conditions can generate aberrant activity, such as seizures. In this study, we examined the effect of GCaMP6 expression in the dentate gyrus (DG) on epileptogenesis. We found that viral expression of GCaMP6s but not GCaMP6f in the DG induces tonic-clonic seizures several weeks after viral injection. Cell-type specific expression of GCaMP6s revealed the granule cells (GCs) as the key player in GCaMP6s-induced epilepsy. Finally, by using slice electrophysiology, we demonstrated that GCaMP6s expression increases neuronal excitability in the GCs. Together, this study highlights the ability of GCaMP6s in DG-associated epileptogenesis.
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Affiliation(s)
- Sasa Teng
- Institute for Genomic Medicine, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY, 10032, USA
- Department of Pathology and Cell Biology, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY, 10032, USA
| | - Wanqi Wang
- Institute for Genomic Medicine, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY, 10032, USA
- Department of Genetics and Development, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY, 10032, USA
| | | | - Jingxuan Wang
- Institute for Genomic Medicine, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY, 10032, USA
| | - Gergely F Turi
- Division of Systems Neuroscience, New York State Psychiatric Institute, New York, NY, 10032, USA
- Department of Psychiatry, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY, 10032, USA
| | - Yueqing Peng
- Institute for Genomic Medicine, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY, 10032, USA.
- Department of Pathology and Cell Biology, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY, 10032, USA.
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12
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Krut' VG, Kalinichenko AL, Maltsev DI, Jappy D, Shevchenko EK, Podgorny OV, Belousov VV. Optogenetic and chemogenetic approaches for modeling neurological disorders in vivo. Prog Neurobiol 2024; 235:102600. [PMID: 38548126 DOI: 10.1016/j.pneurobio.2024.102600] [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: 08/15/2023] [Revised: 02/26/2024] [Accepted: 03/22/2024] [Indexed: 04/01/2024]
Abstract
Animal models of human neurological disorders provide valuable experimental tools which enable us to study various aspects of disorder pathogeneses, ranging from structural abnormalities and disrupted metabolism and signaling to motor and mental deficits, and allow us to test novel therapies in preclinical studies. To be valid, these animal models should recapitulate complex pathological features at the molecular, cellular, tissue, and behavioral levels as closely as possible to those observed in human subjects. Pathological states resembling known human neurological disorders can be induced in animal species by toxins, genetic factors, lesioning, or exposure to extreme conditions. In recent years, novel animal models recapitulating neuropathologies in humans have been introduced. These animal models are based on synthetic biology approaches: opto- and chemogenetics. In this paper, we review recent opto- and chemogenetics-based animal models of human neurological disorders. These models allow for the creation of pathological states by disrupting specific processes at the cellular level. The artificial pathological states mimic a range of human neurological disorders, such as aging-related dementia, Alzheimer's and Parkinson's diseases, amyotrophic lateral sclerosis, epilepsy, and ataxias. Opto- and chemogenetics provide new opportunities unavailable with other animal models of human neurological disorders. These techniques enable researchers to induce neuropathological states varying in severity and ranging from acute to chronic. We also discuss future directions for the development and application of synthetic biology approaches for modeling neurological disorders.
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Affiliation(s)
- Viktoriya G Krut'
- Pirogov Russian National Research Medical University, Moscow 117997, Russia; Federal Center of Brain Research and Neurotechnologies, Federal Medical Biological Agency, Moscow 117997, Russia
| | - Andrei L Kalinichenko
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow 117997, Russia
| | - Dmitry I Maltsev
- Pirogov Russian National Research Medical University, Moscow 117997, Russia; Federal Center of Brain Research and Neurotechnologies, Federal Medical Biological Agency, Moscow 117997, Russia; Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow 117997, Russia
| | - David Jappy
- Federal Center of Brain Research and Neurotechnologies, Federal Medical Biological Agency, Moscow 117997, Russia
| | - Evgeny K Shevchenko
- Federal Center of Brain Research and Neurotechnologies, Federal Medical Biological Agency, Moscow 117997, Russia
| | - Oleg V Podgorny
- Pirogov Russian National Research Medical University, Moscow 117997, Russia; Federal Center of Brain Research and Neurotechnologies, Federal Medical Biological Agency, Moscow 117997, Russia; Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow 117997, Russia.
| | - Vsevolod V Belousov
- Pirogov Russian National Research Medical University, Moscow 117997, Russia; Federal Center of Brain Research and Neurotechnologies, Federal Medical Biological Agency, Moscow 117997, Russia; Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow 117997, Russia; Life Improvement by Future Technologies (LIFT) Center, Skolkovo, Moscow 143025, Russia.
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13
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Kleis P, Paschen E, Häussler U, Haas CA. Low frequency stimulation for seizure suppression: Identification of optimal targets in the entorhinal-hippocampal circuit. Brain Stimul 2024; 17:395-404. [PMID: 38531502 DOI: 10.1016/j.brs.2024.03.017] [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: 01/18/2024] [Revised: 03/15/2024] [Accepted: 03/22/2024] [Indexed: 03/28/2024] Open
Abstract
BACKGROUND Mesial temporal lobe epilepsy (MTLE) with hippocampal sclerosis (HS) is a common form of drug-resistant focal epilepsy in adults. Treatment for pharmacoresistant patients remains a challenge, with deep brain stimulation (DBS) showing promise for alleviating intractable seizures. This study explores the efficacy of low frequency stimulation (LFS) on specific neuronal targets within the entorhinal-hippocampal circuit in a mouse model of MTLE. OBJECTIVE Our previous research demonstrated that LFS of the medial perforant path (MPP) fibers in the sclerotic hippocampus reduced seizures in epileptic mice. Here, we aimed to identify the critical neuronal population responsible for this antiepileptic effect by optogenetically stimulating presynaptic and postsynaptic compartments of the MPP-dentate granule cell (DGC) synapse at 1 Hz. We hypothesize that specific targets for LFS can differentially influence seizure activity depending on the cellular identity and location within or outside the seizure focus. METHODS We utilized the intrahippocampal kainate (ihKA) mouse model of MTLE and targeted specific neural populations using optogenetic stimulation. We recorded intracranial neuronal activity from freely moving chronically epileptic mice with and without optogenetic LFS up to 3 h. RESULTS We found that LFS of MPP fibers in the sclerotic hippocampus effectively suppressed epileptiform activity while stimulating principal cells in the MEC had no impact. Targeting DGCs in the sclerotic septal or non-sclerotic temporal hippocampus with LFS did not reduce seizure numbers but shortened the epileptiform bursts. CONCLUSION Presynaptic stimulation of the MPP-DGC synapse within the sclerotic hippocampus is critical for seizure suppression via LFS.
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Affiliation(s)
- Piret Kleis
- Experimental Epilepsy Research, Department of Neurosurgery, Medical Center - University of Freiburg, Faculty of Medicine, Freiburg, Germany; Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Enya Paschen
- Experimental Epilepsy Research, Department of Neurosurgery, Medical Center - University of Freiburg, Faculty of Medicine, Freiburg, Germany; Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Ute Häussler
- Experimental Epilepsy Research, Department of Neurosurgery, Medical Center - University of Freiburg, Faculty of Medicine, Freiburg, Germany; BrainLinks-BrainTools Center, University of Freiburg, Freiburg, Germany
| | - Carola A Haas
- Experimental Epilepsy Research, Department of Neurosurgery, Medical Center - University of Freiburg, Faculty of Medicine, Freiburg, Germany; BrainLinks-BrainTools Center, University of Freiburg, Freiburg, Germany.
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14
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Alcantara-Gonzalez D, Kennedy M, Criscuolo C, Botterill J, Scharfman HE. Increased excitability of dentate gyrus mossy cells occurs early in life in the Tg2576 model of Alzheimer's disease. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.09.579729. [PMID: 38645244 PMCID: PMC11027210 DOI: 10.1101/2024.02.09.579729] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/23/2024]
Abstract
INTRODUCTION Hyperexcitability in Alzheimer's disease (AD) emerge early and contribute to disease progression. The dentate gyrus (DG) is implicated in hyperexcitability in AD. We hypothesized that mossy cells (MCs), regulators of DG excitability, contribute to early hyperexcitability in AD. Indeed, MCs generate hyperexcitability in epilepsy. METHODS Using the Tg2576 model and WT mice (∼1month-old), we compared MCs electrophysiologically, assessed c-Fos activity marker, Aβ expression and mice performance in a hippocampal-dependent memory task. RESULTS Tg2576 MCs exhibit increased spontaneous excitatory events and decreased inhibitory currents, increasing the charge transfer excitation/inhibition ratio. Tg2576 MC intrinsic excitability was enhanced, and showed higher c-Fos, intracellular Aβ expression, and axon sprouting. Granule cells only showed changes in synaptic properties, without intrinsic changes. The effects occurred before a memory task is affected. DISCUSSION Early electrophysiological and morphological alterations in Tg2576 MCs are consistent with enhanced excitability, suggesting an early role in DG hyperexcitability and AD pathophysiology. HIGHLIGHTS ∘ MCs from 1 month-old Tg2576 mice had increased spontaneous excitatory synaptic input. ∘ Tg2576 MCs had reduced spontaneous inhibitory synaptic input. ∘ Several intrinsic properties were abnormal in Tg2576 MCs. ∘ Tg2576 GCs had enhanced synaptic excitation but no changes in intrinsic properties. ∘ Tg2576 MCs exhibited high c-Fos expression, soluble Aβ and axonal sprouting.
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15
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Nguyen QA, Klein PM, Xie C, Benthall KN, Iafrati J, Homidan J, Bendor JT, Dudok B, Farrell JS, Gschwind T, Porter CL, Keravala A, Dodson GS, Soltesz I. Acetylcholine receptor based chemogenetics engineered for neuronal inhibition and seizure control assessed in mice. Nat Commun 2024; 15:601. [PMID: 38238329 PMCID: PMC10796428 DOI: 10.1038/s41467-024-44853-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Accepted: 01/09/2024] [Indexed: 01/22/2024] Open
Abstract
Epilepsy is a prevalent disorder involving neuronal network hyperexcitability, yet existing therapeutic strategies often fail to provide optimal patient outcomes. Chemogenetic approaches, where exogenous receptors are expressed in defined brain areas and specifically activated by selective agonists, are appealing methods to constrain overactive neuronal activity. We developed BARNI (Bradanicline- and Acetylcholine-activated Receptor for Neuronal Inhibition), an engineered channel comprised of the α7 nicotinic acetylcholine receptor ligand-binding domain coupled to an α1 glycine receptor anion pore domain. Here we demonstrate that BARNI activation by the clinical stage α7 nicotinic acetylcholine receptor-selective agonist bradanicline effectively suppressed targeted neuronal activity, and controlled both acute and chronic seizures in male mice. Our results provide evidence for the use of an inhibitory acetylcholine-based engineered channel activatable by both exogenous and endogenous agonists as a potential therapeutic approach to treating epilepsy.
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Affiliation(s)
- Quynh-Anh Nguyen
- Department of Neurosurgery, Stanford University, Stanford, CA, 94305, USA.
| | - Peter M Klein
- Department of Neurosurgery, Stanford University, Stanford, CA, 94305, USA.
| | - Cheng Xie
- CODA Biotherapeutics, 240 East Grand Ave., South San Francisco, CA, 94080, USA
| | - Katelyn N Benthall
- CODA Biotherapeutics, 240 East Grand Ave., South San Francisco, CA, 94080, USA
| | - Jillian Iafrati
- CODA Biotherapeutics, 240 East Grand Ave., South San Francisco, CA, 94080, USA
| | - Jesslyn Homidan
- Department of Neurosurgery, Stanford University, Stanford, CA, 94305, USA
| | - Jacob T Bendor
- CODA Biotherapeutics, 240 East Grand Ave., South San Francisco, CA, 94080, USA
| | - Barna Dudok
- Department of Neurosurgery, Stanford University, Stanford, CA, 94305, USA
- Department of Neurology, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Jordan S Farrell
- Department of Neurosurgery, Stanford University, Stanford, CA, 94305, USA
| | - Tilo Gschwind
- Department of Neurosurgery, Stanford University, Stanford, CA, 94305, USA
| | - Charlotte L Porter
- Department of Neurosurgery, Stanford University, Stanford, CA, 94305, USA
| | - Annahita Keravala
- CODA Biotherapeutics, 240 East Grand Ave., South San Francisco, CA, 94080, USA
| | - G Steven Dodson
- CODA Biotherapeutics, 240 East Grand Ave., South San Francisco, CA, 94080, USA
| | - Ivan Soltesz
- Department of Neurosurgery, Stanford University, Stanford, CA, 94305, USA
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16
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Forte N, Nicois A, Marfella B, Mavaro I, D'Angelo L, Piscitelli F, Scandurra A, De Girolamo P, Baldelli P, Benfenati F, Di Marzo V, Cristino L. Early endocannabinoid-mediated depolarization-induced suppression of excitation delays the appearance of the epileptic phenotype in synapsin II knockout mice. Cell Mol Life Sci 2024; 81:37. [PMID: 38214769 PMCID: PMC11072294 DOI: 10.1007/s00018-023-05029-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Revised: 10/16/2023] [Accepted: 10/31/2023] [Indexed: 01/13/2024]
Abstract
The mechanism underlying the transition from the pre-symptomatic to the symptomatic state is a crucial aspect of epileptogenesis. SYN2 is a member of a multigene family of synaptic vesicle phosphoproteins playing a fundamental role in controlling neurotransmitter release. Human SYN2 gene mutations are associated with epilepsy and autism spectrum disorder. Mice knocked out for synapsin II (SynII KO) are prone to epileptic seizures that appear after 2 months of age. However, the involvement of the endocannabinoid system, known to regulate seizure development and propagation, in the modulation of the excitatory/inhibitory balance in the epileptic hippocampal network of SynII KO mice has not been explored. In this study, we investigated the impact of endocannabinoids on glutamatergic and GABAergic synapses at hippocampal dentate gyrus granule cells in young pre-symptomatic (1-2 months old) and adult symptomatic (5-8 months old) SynII KO mice. We observed an increase in endocannabinoid-mediated depolarization-induced suppression of excitation in young SynII KO mice, compared to age-matched wild-type controls. In contrast, the endocannabinoid-mediated depolarization-induced suppression of inhibition remained unchanged in SynII KO mice at both ages. This selective alteration of excitatory synaptic transmission was accompanied by changes in hippocampal endocannabinoid levels and cannabinoid receptor type 1 distribution among glutamatergic and GABAergic synaptic terminals contacting the granule cells of the dentate gyrus. Finally, inhibition of type-1 cannabinoid receptors in young pre-symptomatic SynII KO mice induced seizures during a tail suspension test. Our results suggest that endocannabinoids contribute to maintaining network stability in a genetic mouse model of human epilepsy.
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Affiliation(s)
- Nicola Forte
- Institute of Biomolecular Chemistry, National Research Council of Italy, Pozzuoli (NA), Italy
| | - Alessandro Nicois
- Institute of Biomolecular Chemistry, National Research Council of Italy, Pozzuoli (NA), Italy
| | - Brenda Marfella
- Institute of Biomolecular Chemistry, National Research Council of Italy, Pozzuoli (NA), Italy
| | - Isabella Mavaro
- Institute of Biomolecular Chemistry, National Research Council of Italy, Pozzuoli (NA), Italy
| | - Livia D'Angelo
- Department of Veterinary Medicine and Animal Production, University of Naples Federico II, Naples, Italy
| | - Fabiana Piscitelli
- Institute of Biomolecular Chemistry, National Research Council of Italy, Pozzuoli (NA), Italy
| | - Anna Scandurra
- Department of Biology, University of Naples Federico II, Naples, Italy
| | - Paolo De Girolamo
- Department of Veterinary Medicine and Animal Production, University of Naples Federico II, Naples, Italy
| | - Pietro Baldelli
- Department of Experimental Medicine, University of Genoa, Genoa, Italy
- IRCCS Ospedale Policlinico San Martino, Genoa, Italy
| | - Fabio Benfenati
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Genoa, Italy
- IRCCS Ospedale Policlinico San Martino, Genoa, Italy
| | - Vincenzo Di Marzo
- Institute of Biomolecular Chemistry, National Research Council of Italy, Pozzuoli (NA), Italy.
- Faculty of Medicine and Faculty of Agricultural and Food Sciences, Canada Excellence Research Chair on the Microbiome-Endocannabinoidome Axis in Metabolic Health, Université Laval, Québec City, QC, Canada.
- Heart and Lung Research Institute of Université Laval, Québec City, QC, Canada.
- Institute for Nutrition and Functional Foods, Centre NUTRISS, Université Laval, Québec City, QC, Canada.
| | - Luigia Cristino
- Institute of Biomolecular Chemistry, National Research Council of Italy, Pozzuoli (NA), Italy.
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Vergaelen M, Manzella S, Vonck K, Craey E, Spanoghe J, Sprengers M, Carrette E, Wadman WJ, Delbeke J, Boon P, Larsen LE, Raedt R. Increased Dentate Gyrus Excitability in the Intrahippocampal Kainic Acid Mouse Model for Temporal Lobe Epilepsy. Int J Mol Sci 2024; 25:660. [PMID: 38203829 PMCID: PMC10779277 DOI: 10.3390/ijms25010660] [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: 11/29/2023] [Revised: 12/29/2023] [Accepted: 01/02/2024] [Indexed: 01/12/2024] Open
Abstract
The intrahippocampal kainic acid (IHKA) mouse model is an extensively used in vivo model to investigate the pathophysiology of mesial temporal lobe epilepsy (mTLE) and to develop novel therapies for drug-resistant epilepsy. It is characterized by profound hippocampal sclerosis and spontaneously occurring seizures with a major role for the injected damaged hippocampus, but little is known about the excitability of specific subregions. The purpose of this study was to electrophysiologically characterize the excitability of hippocampal subregions in the chronic phase of the induced epilepsy in the IHKA mouse model. We recorded field postsynaptic potentials (fPSPs) after electrical stimulation in the CA1 region and in the dentate gyrus (DG) of hippocampal slices of IHKA and healthy mice using a multielectrode array (MEA). In the DG, a significantly steeper fPSP slope was found, reflecting higher synaptic strength. Population spikes were more prevalent with a larger spatial distribution in the IHKA group, reflecting a higher degree of granule cell output. Only minor differences were found in the CA1 region. These results point to increased neuronal excitability in the DG but not in the CA1 region of the hippocampus of IHKA mice. This method, in which the excitability of hippocampal slices from IHKA mice is investigated using a MEA, can now be further explored as a potential new model to screen for new interventions that can restore DG function and potentially lead to novel therapies for mTLE.
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Affiliation(s)
- Marijke Vergaelen
- 4BRAIN, Department of Head and Skin, Ghent University, 9000 Ghent, Belgium
| | - Simona Manzella
- 4BRAIN, Department of Head and Skin, Ghent University, 9000 Ghent, Belgium
| | - Kristl Vonck
- 4BRAIN, Department of Head and Skin, Ghent University, 9000 Ghent, Belgium
| | - Erine Craey
- 4BRAIN, Department of Head and Skin, Ghent University, 9000 Ghent, Belgium
| | - Jeroen Spanoghe
- 4BRAIN, Department of Head and Skin, Ghent University, 9000 Ghent, Belgium
| | - Mathieu Sprengers
- 4BRAIN, Department of Head and Skin, Ghent University, 9000 Ghent, Belgium
| | - Evelien Carrette
- 4BRAIN, Department of Head and Skin, Ghent University, 9000 Ghent, Belgium
| | - Wytse Jan Wadman
- 4BRAIN, Department of Head and Skin, Ghent University, 9000 Ghent, Belgium
| | - Jean Delbeke
- 4BRAIN, Department of Head and Skin, Ghent University, 9000 Ghent, Belgium
| | - Paul Boon
- 4BRAIN, Department of Head and Skin, Ghent University, 9000 Ghent, Belgium
| | - Lars Emil Larsen
- 4BRAIN, Department of Head and Skin, Ghent University, 9000 Ghent, Belgium
- MEDISIP, Department of Electronics and Information Systems, Ghent University, 9000 Ghent, Belgium
| | - Robrecht Raedt
- 4BRAIN, Department of Head and Skin, Ghent University, 9000 Ghent, Belgium
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Proddutur A, Nguyen S, Yeh CW, Gupta A, Santhakumar V. Reclusive chandeliers: Functional isolation of dentate axo-axonic cells after experimental status epilepticus. Prog Neurobiol 2023; 231:102542. [PMID: 37898313 PMCID: PMC10842856 DOI: 10.1016/j.pneurobio.2023.102542] [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: 05/02/2023] [Revised: 10/22/2023] [Accepted: 10/24/2023] [Indexed: 10/30/2023]
Abstract
Axo-axonic cells (AACs) provide specialized inhibition to the axon initial segment (AIS) of excitatory neurons and can regulate network output and synchrony. Although hippocampal dentate AACs are structurally altered in epilepsy, physiological analyses of dentate AACs are lacking. We demonstrate that parvalbumin neurons in the dentate molecular layer express PTHLH, an AAC marker, and exhibit morphology characteristic of AACs. Dentate AACs show high-frequency, non-adapting firing but lack persistent firing in the absence of input and have higher rheobase than basket cells suggesting that AACs can respond reliably to network activity. Early after pilocarpine-induced status epilepticus (SE), dentate AACs receive fewer spontaneous excitatory and inhibitory synaptic inputs and have significantly lower maximum firing frequency. Paired recordings and spatially localized optogenetic stimulation revealed that SE reduced the amplitude of unitary synaptic inputs from AACs to granule cells without altering reliability, short-term plasticity, or AIS GABA reversal potential. These changes compromised AAC-dependent shunting of granule cell firing in a multicompartmental model. These early post-SE changes in AAC physiology would limit their ability to receive and respond to input, undermining a critical brake on the dentate throughput during epileptogenesis.
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Affiliation(s)
- Archana Proddutur
- Department of Pharmacology, Physiology and Neuroscience, Rutgers New Jersey Medical School, Newark, NJ 07103, USA; Department of Molecular, Cell and Systems Biology, University of California Riverside, Riverside, CA 92521, USA
| | - Susan Nguyen
- Department of Molecular, Cell and Systems Biology, University of California Riverside, Riverside, CA 92521, USA
| | - Chia-Wei Yeh
- Department of Molecular, Cell and Systems Biology, University of California Riverside, Riverside, CA 92521, USA
| | - Akshay Gupta
- Department of Pharmacology, Physiology and Neuroscience, Rutgers New Jersey Medical School, Newark, NJ 07103, USA; Department of Molecular, Cell and Systems Biology, University of California Riverside, Riverside, CA 92521, USA
| | - Vijayalakshmi Santhakumar
- Department of Pharmacology, Physiology and Neuroscience, Rutgers New Jersey Medical School, Newark, NJ 07103, USA; Department of Molecular, Cell and Systems Biology, University of California Riverside, Riverside, CA 92521, USA.
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19
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Wenzel M, Huberfeld G, Grayden DB, de Curtis M, Trevelyan AJ. A debate on the neuronal origin of focal seizures. Epilepsia 2023; 64 Suppl 3:S37-S48. [PMID: 37183507 DOI: 10.1111/epi.17650] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Revised: 04/26/2023] [Accepted: 05/12/2023] [Indexed: 05/16/2023]
Abstract
A critical question regarding how focal seizures start is whether we can identify particular cell classes that drive the pathological process. This was the topic for debate at the recent International Conference for Technology and Analysis of Seizures (ICTALS) meeting (July 2022, Bern, CH) that we summarize here. The debate has been fueled in recent times by the introduction of powerful new ways to manipulate subpopulations of cells in relative isolation, mostly using optogenetics. The motivation for resolving the debate is to identify novel targets for therapeutic interventions through a deeper understanding of the etiology of seizures.
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Affiliation(s)
- Michael Wenzel
- Department of Epileptology, University Hospital Bonn, University of Bonn, Bonn, Germany
| | - Gilles Huberfeld
- Neurology Department, Hopital Fondation Adolphe de Rothschild, Paris, France
- Center for Interdisciplinary Research in Biology (CIRB), College de France, CNRS, INSERM, Université PSL, Paris, France
| | - David B Grayden
- Department of Biomedical Engineering, The University of Melbourne, Melbourne, Victoria, Australia
- Department of Medicine, St Vincent's Hospital, The University of Melbourne, Melbourne, Victoria, Australia
- Graeme Clark Institute, The University of Melbourne, Melbourne, Victoria, Australia
| | - Marco de Curtis
- Epilepsy Unit, Fondazione I.R.C.C.S., Istituto Neurologico Carlo Besta, Milan, Italy
| | - Andrew J Trevelyan
- Newcastle University Biosciences Institute, Medical School, Framlington Place, Newcastle upon Tyne, UK
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20
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Kurki SN, Srinivasan R, Laine J, Virtanen MA, Ala-Kurikka T, Voipio J, Kaila K. Acute neuroinflammation leads to disruption of neuronal chloride regulation and consequent hyperexcitability in the dentate gyrus. Cell Rep 2023; 42:113379. [PMID: 37922309 DOI: 10.1016/j.celrep.2023.113379] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Revised: 09/15/2023] [Accepted: 10/19/2023] [Indexed: 11/05/2023] Open
Abstract
Neuroinflammation is a salient part of diverse neurological and psychiatric pathologies that associate with neuronal hyperexcitability, but the underlying molecular and cellular mechanisms remain to be identified. Here, we show that peripheral injection of lipopolysaccharide (LPS) renders the dentate gyrus (DG) hyperexcitable to perforant pathway stimulation in vivo and increases the internal spiking propensity of dentate granule cells (DGCs) in vitro 24 h post-injection (hpi). In parallel, LPS leads to a prominent downregulation of chloride extrusion via KCC2 and to the emergence of NKCC1-mediated chloride uptake in DGCs under experimental conditions optimized to detect specific changes in transporter efficacy. These data show that acute neuroinflammation leads to disruption of neuronal chloride regulation, which unequivocally results in a loss of GABAergic inhibition in the DGCs, collapsing the gating function of the DG. The present work provides a mechanistic explanation for neuroinflammation-driven hyperexcitability and consequent cognitive disturbance.
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Affiliation(s)
- Samu N Kurki
- Faculty of Biological and Environmental Sciences, Molecular and Integrative Biosciences, University of Helsinki, Helsinki, Finland; Neuroscience Center (HiLIFE), University of Helsinki, Helsinki, Finland.
| | - Rakenduvadhana Srinivasan
- Faculty of Biological and Environmental Sciences, Molecular and Integrative Biosciences, University of Helsinki, Helsinki, Finland; Neuroscience Center (HiLIFE), University of Helsinki, Helsinki, Finland
| | - Jens Laine
- Faculty of Biological and Environmental Sciences, Molecular and Integrative Biosciences, University of Helsinki, Helsinki, Finland; Neuroscience Center (HiLIFE), University of Helsinki, Helsinki, Finland
| | - Mari A Virtanen
- Faculty of Biological and Environmental Sciences, Molecular and Integrative Biosciences, University of Helsinki, Helsinki, Finland; Neuroscience Center (HiLIFE), University of Helsinki, Helsinki, Finland
| | - Tommi Ala-Kurikka
- Faculty of Biological and Environmental Sciences, Molecular and Integrative Biosciences, University of Helsinki, Helsinki, Finland; Neuroscience Center (HiLIFE), University of Helsinki, Helsinki, Finland
| | - Juha Voipio
- Faculty of Biological and Environmental Sciences, Molecular and Integrative Biosciences, University of Helsinki, Helsinki, Finland
| | - Kai Kaila
- Faculty of Biological and Environmental Sciences, Molecular and Integrative Biosciences, University of Helsinki, Helsinki, Finland; Neuroscience Center (HiLIFE), University of Helsinki, Helsinki, Finland.
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21
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Zhu ZA, Li YY, Xu J, Xue H, Feng X, Zhu YC, Xiong ZQ. CDKL5 deficiency in adult glutamatergic neurons alters synaptic activity and causes spontaneous seizures via TrkB signaling. Cell Rep 2023; 42:113202. [PMID: 37777961 DOI: 10.1016/j.celrep.2023.113202] [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: 05/04/2023] [Revised: 07/26/2023] [Accepted: 09/16/2023] [Indexed: 10/03/2023] Open
Abstract
CDKL5 deficiency disorder (CDD) is a severe epileptic encephalopathy resulting from pathological mutations in the X-linked cyclin-dependent kinase-like 5 (CDKL5) gene. Despite significant progress in understanding the neuronal function of CDKL5, the molecular mechanisms underlying CDD-associated epileptogenesis are unknown. Here, we report that acute ablation of CDKL5 from adult forebrain glutamatergic neurons leads to elevated neural network activity in the dentate gyrus and the occurrence of early-onset spontaneous seizures via tropomyosin-related kinase B (TrkB) signaling. We observe increased expression of brain-derived neurotrophic factor (BDNF) and enhanced activation of its receptor TrkB in the hippocampus of Cdkl5-deficient mice prior to the onset of behavioral seizures. Moreover, reducing TrkB signaling in these mice rescues the altered synaptic activity and suppresses recurrent seizures. These results suggest that TrkB signaling mediates epileptogenesis in a mouse model of CDD and that targeting this pathway might be effective for treating epilepsy in patients affected by CDKL5 mutations.
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Affiliation(s)
- Zi-Ai Zhu
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Shanghai 200031, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yi-Yan Li
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Shanghai 200031, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Juan Xu
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Shanghai 200031, China
| | - Hui Xue
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Shanghai 200031, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xue Feng
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Shanghai 200031, China
| | - Yong-Chuan Zhu
- Shanghai Key Laboratory of Psychotic Disorders, Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai 200030, China.
| | - Zhi-Qi Xiong
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Shanghai 200031, China; University of Chinese Academy of Sciences, Beijing 100049, China; School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China; Shanghai Center for Brain Science and Brain-Inspired Intelligence Technology, Shanghai 201210, China; School of Future Technology, University of Chinese Academy of Sciences, Beijing 100049, China.
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22
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Tescarollo FC, Valdivia D, Chen S, Sun H. Unilateral optogenetic kindling of hippocampus leads to more severe impairments of the inhibitory signaling in the contralateral hippocampus. Front Mol Neurosci 2023; 16:1268311. [PMID: 37942301 PMCID: PMC10627882 DOI: 10.3389/fnmol.2023.1268311] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Accepted: 09/20/2023] [Indexed: 11/10/2023] Open
Abstract
The kindling model has been used extensively by researchers to study the neurobiology of temporal lobe epilepsy (TLE) due to its capacity to induce intensification of seizures by the progressive recruitment of additional neuronal clusters into epileptogenic networks. We applied repetitive focal optogenetic activation of putative excitatory neurons in the dorsal CA1 area of the hippocampus of mice to investigate the role of inhibitory signaling during this process. This experimental protocol resulted in a kindling phenotype that was maintained for 2 weeks after the animals were fully kindled. As a result of the different phases of optogenetic kindling (OpK), key inhibitory signaling elements, such as KCC2 and NKCC1, exhibited distinct temporal and spatial dynamics of regulation. These alterations in protein expression were related to the distinct pattern of ictal activity propagation through the different hippocampal sublayers. Our results suggest the KCC2 disruption in the contralateral hippocampus of fully kindled animals progressively facilitated the creation of pathological pathways for seizure propagation through the hippocampal network. Upon completion of kindling, we observed animals that were restimulated after a rest period of 14-day showed, besides a persistent KCC2 downregulation, an NKCC1 upregulation in the bilateral dentate gyrus and hippocampus-wide loss of parvalbumin-positive interneurons. These alterations observed in the chronic phase of OpK suggest that the hippocampus of rekindled animals continued to undergo self-modifications during the rest period. The changes resulting from this period suggest the possibility of the development of a mirror focus on the hippocampus contralateral to the site of optical stimulations. Our results offer perspectives for preventing the recruitment and conversion of healthy neuronal networks into epileptogenic ones among patients with epilepsy.
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Affiliation(s)
| | | | | | - Hai Sun
- Department of Neurosurgery, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ, United States
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23
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Manning A, Han V, Stephens A, Wang R, Bush N, Bard M, Ramirez JM, Kalume F. Elevated susceptibility to exogenous seizure triggers and impaired interneuron excitability in a mouse model of Leigh syndrome epilepsy. Neurobiol Dis 2023; 187:106288. [PMID: 37704057 PMCID: PMC10621616 DOI: 10.1016/j.nbd.2023.106288] [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: 05/28/2023] [Revised: 08/12/2023] [Accepted: 09/10/2023] [Indexed: 09/15/2023] Open
Abstract
Mutations in the NADH dehydrogenase (ubiquinone reductase) iron‑sulfur protein 4 (NDUFS4) gene, which encodes for a key structural subunit of the OXFOS complex I (CI), lead to the most common form of mitochondrial disease in children known as Leigh syndrome (LS). As in other mitochondrial diseases, epileptic seizures constitute one of the most significant clinical features of LS. These seizures are often very difficult to treat and are a sign of poor disease prognosis. Mice with whole-body Ndufs4 KO are a well-validated model of LS; they exhibit epilepsy and several other clinical features of LS. We have previously shown that mice with Ndufs4 KO in only GABAergic interneurons (Gad2-Ndufs4-KO) reproduce the severe epilepsy phenotype observed in the global KO mice. This observation indicated that these mice represent an excellent model of LS epilepsy isolated from other clinical manifestations of the disease. To further characterize this epilepsy phenotype, we investigated seizure susceptibility to selected exogenous seizure triggers in Gad2-Ndufs4-KO mice. Then, using electrophysiology, imaging, and immunohistochemistry, we studied the cellular, physiological, and neuroanatomical consequences of Ndufs4 KO in GABAergic interneurons. Homozygous KO of Ndufs4 in GABAergic interneurons leads to a prominent susceptibility to exogenous seizure triggers, impaired interneuron excitability and interneuron loss. Finally, we found that the hippocampus and cortex participate in the generation of seizure activity in Gad2-Ndufs4-KO mice. These findings further define the LS epilepsy phenotype and provide important insights into the cellular mechanisms underlying epilepsy in LS and other mitochondrial diseases.
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Affiliation(s)
- Arena Manning
- Graduate Program in Neuroscience, University of Washington, Seattle, WA, United States of America; Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, United States of America
| | - Victor Han
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, United States of America
| | - Alexa Stephens
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, United States of America
| | - Rose Wang
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, United States of America
| | - Nicholas Bush
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, United States of America
| | - Michelle Bard
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, United States of America
| | - Jan M Ramirez
- Graduate Program in Neuroscience, University of Washington, Seattle, WA, United States of America; Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, United States of America; Department of Neurological Surgery, University of Washington, Seattle, WA, United States of America
| | - Franck Kalume
- Graduate Program in Neuroscience, University of Washington, Seattle, WA, United States of America; Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, United States of America; Department of Neurological Surgery, University of Washington, Seattle, WA, United States of America.
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24
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Proddutur A, Nguyen S, Yeh CW, Gupta A, Santhakumar V. RECLUSIVE CHANDELIERS: FUNCTIONAL ISOLATION OF DENTATE AXO-AXONIC CELLS AFTER EXPERIMENTAL STATUS EPILEPTICUS. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.01.560378. [PMID: 37873292 PMCID: PMC10592856 DOI: 10.1101/2023.10.01.560378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2023]
Abstract
Axo-axonic cells (AACs) provide specialized inhibition to the axon initial segment (AIS) of excitatory neurons and can regulate network output and synchrony. Although hippocampal dentate AACs are structurally altered in epilepsy, physiological analyses of dentate AACs are lacking. We demonstrate that parvalbumin neurons in the dentate molecular layer express PTHLH, an AAC marker, and exhibit morphology characteristic of AACs. Dentate AACs show high-frequency, non-adapting firing but lack persistent firing in the absence of input and have higher rheobase than basket cells suggesting that AACs can respond reliably to network activity. Early after pilocarpine-induced status epilepticus (SE), dentate AACs receive fewer spontaneous excitatory and inhibitory synaptic inputs and have significantly lower maximum firing frequency. Paired recordings and spatially localized optogenetic stimulation revealed that SE reduced the amplitude of unitary synaptic inputs from AACs to granule cells without altering reliability, short-term plasticity, or AIS GABA reversal potential. These changes compromised AAC-dependent shunting of granule cell firing in a multicompartmental model. These early post-SE changes in AAC physiology would limit their ability to receive and respond to input, undermining a critical brake on the dentate throughput during epileptogenesis.
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Affiliation(s)
- Archana Proddutur
- Department of Pharmacology, Physiology and Neuroscience, Rutgers New Jersey Medical School, Newark, New Jersey 07103
- Department of Molecular, Cell and Systems Biology, University of California Riverside, Riverside, California 92521
| | - Susan Nguyen
- Department of Molecular, Cell and Systems Biology, University of California Riverside, Riverside, California 92521
| | - Chia-Wei Yeh
- Department of Molecular, Cell and Systems Biology, University of California Riverside, Riverside, California 92521
| | - Akshay Gupta
- Department of Pharmacology, Physiology and Neuroscience, Rutgers New Jersey Medical School, Newark, New Jersey 07103
- Department of Molecular, Cell and Systems Biology, University of California Riverside, Riverside, California 92521
| | - Vijayalakshmi Santhakumar
- Department of Pharmacology, Physiology and Neuroscience, Rutgers New Jersey Medical School, Newark, New Jersey 07103
- Department of Molecular, Cell and Systems Biology, University of California Riverside, Riverside, California 92521
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25
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Mueller JS, Tescarollo FC, Huynh T, Brenner DA, Valdivia DJ, Olagbegi K, Sangappa S, Chen SC, Sun H. Ictogenesis proceeds through discrete phases in hippocampal CA1 seizures in mice. Nat Commun 2023; 14:6010. [PMID: 37752179 PMCID: PMC10522592 DOI: 10.1038/s41467-023-41711-x] [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: 03/07/2023] [Accepted: 09/15/2023] [Indexed: 09/28/2023] Open
Abstract
Epilepsy is characterized by spontaneous non-provoked seizures, yet the mechanisms that trigger a seizure and allow its evolution remain underexplored. To dissect out phases of ictogenesis, we evoked hypersynchronous activity with optogenetic stimulation. Focal optogenetic activation of putative excitatory neurons in the mouse hippocampal CA1 reliably evoked convulsive seizures in awake mice. A time-vs-time pulsogram plot characterized the evolution of the EEG pulse response from a light evoked response to induced seizure activity. Our results depict ictogenesis as a stepwise process comprised of three distinctive phases demarcated by two transition points. The induction phase undergoes the first transition to reverberant phase activity, followed by the second transition into the paroxysmal phase or a seizure. Non-seizure responses are confined to either induction or reverberant phases. The pulsogram was then constructed in seizures recorded from a murine model of temporal lobe epilepsy and it depicted a similar reverberance preceding spontaneous seizures. The discovery of these distinct phases of ictogenesis may offer means to abort a seizure before it develops.
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Affiliation(s)
- John-Sebastian Mueller
- Department of Neurosurgery, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ, 08854, USA
| | - Fabio C Tescarollo
- Department of Neurosurgery, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ, 08854, USA
| | - Trong Huynh
- Department of Neurosurgery, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ, 08854, USA
- Department of Surgery, Rutgers New Jersey Medical School, Newark, NJ, 07103, USA
| | - Daniel A Brenner
- Department of Neurosurgery, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ, 08854, USA
| | - Daniel J Valdivia
- Department of Neurosurgery, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ, 08854, USA
| | - Kanyin Olagbegi
- Department of Neurosurgery, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ, 08854, USA
| | - Sahana Sangappa
- Department of Neurosurgery, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ, 08854, USA
| | - Spencer C Chen
- Department of Neurosurgery, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ, 08854, USA
| | - Hai Sun
- Department of Neurosurgery, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ, 08854, USA.
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26
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Schoeters R, Tarnaud T, Weyn L, Joseph W, Raedt R, Tanghe E. Quantitative analysis of the optogenetic excitability of CA1 neurons. Front Comput Neurosci 2023; 17:1229715. [PMID: 37649730 PMCID: PMC10465168 DOI: 10.3389/fncom.2023.1229715] [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: 05/26/2023] [Accepted: 07/27/2023] [Indexed: 09/01/2023] Open
Abstract
Introduction Optogenetics has emerged as a promising technique for modulating neuronal activity and holds potential for the treatment of neurological disorders such as temporal lobe epilepsy (TLE). However, clinical translation still faces many challenges. This in-silico study aims to enhance the understanding of optogenetic excitability in CA1 cells and to identify strategies for improving stimulation protocols. Methods Employing state-of-the-art computational models coupled with Monte Carlo simulated light propagation, the optogenetic excitability of four CA1 cells, two pyramidal and two interneurons, expressing ChR2(H134R) is investigated. Results and discussion The results demonstrate that confining the opsin to specific neuronal membrane compartments significantly improves excitability. An improvement is also achieved by focusing the light beam on the most excitable cell region. Moreover, the perpendicular orientation of the optical fiber relative to the somato-dendritic axis yields superior results. Inter-cell variability is observed, highlighting the importance of considering neuron degeneracy when designing optogenetic tools. Opsin confinement to the basal dendrites of the pyramidal cells renders the neuron the most excitable. A global sensitivity analysis identified opsin location and expression level as having the greatest impact on simulation outcomes. The error reduction of simulation outcome due to coupling of neuron modeling with light propagation is shown. The results promote spatial confinement and increased opsin expression levels as important improvement strategies. On the other hand, uncertainties in these parameters limit precise determination of the irradiance thresholds. This study provides valuable insights on optogenetic excitability of CA1 cells useful for the development of improved optogenetic stimulation protocols for, for instance, TLE treatment.
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Affiliation(s)
- Ruben Schoeters
- WAVES, Department of Information Technology (INTEC), Ghent University/IMEC, Ghent, Belgium
- 4BRAIN, Department of Neurology, Institute for Neuroscience, Ghent University, Ghent, Belgium
| | - Thomas Tarnaud
- WAVES, Department of Information Technology (INTEC), Ghent University/IMEC, Ghent, Belgium
| | - Laila Weyn
- WAVES, Department of Information Technology (INTEC), Ghent University/IMEC, Ghent, Belgium
- 4BRAIN, Department of Neurology, Institute for Neuroscience, Ghent University, Ghent, Belgium
| | - Wout Joseph
- WAVES, Department of Information Technology (INTEC), Ghent University/IMEC, Ghent, Belgium
| | - Robrecht Raedt
- 4BRAIN, Department of Neurology, Institute for Neuroscience, Ghent University, Ghent, Belgium
| | - Emmeric Tanghe
- WAVES, Department of Information Technology (INTEC), Ghent University/IMEC, Ghent, Belgium
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27
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Almeida J, Martins AR, Amaral L, Valério D, Bukhari Q, Schu G, Nogueira J, Spínola M, Soleimani G, Fernandes F, Silva AR, Fregni F, Simis M, Simões M, Peres A. The cerebellum is causally involved in episodic memory under aging. GeroScience 2023; 45:2267-2287. [PMID: 36749471 PMCID: PMC10651631 DOI: 10.1007/s11357-023-00738-0] [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: 10/21/2022] [Accepted: 01/17/2023] [Indexed: 02/08/2023] Open
Abstract
Episodic memory decline is a major signature of both normal and pathological aging. Many neural regions have been implicated in the processes subserving both episodic memory and typical aging decline. Here, we demonstrate that the cerebellum is causally involved episodic memory under aging. We show that a 12-day neurostimulation program delivered to the right cerebellum led to improvements in episodic memory performance under healthy aging that long outlast the stimulation period - healthy elderly individuals show episodic memory improvement both immediately after the intervention program and in a 4-month follow-up. These results demonstrate the causal relevance of the cerebellum in processes associated with long-term episodic memory, potentially highlighting its role in regulating and maintaining cognitive processing. Moreover, they point to the importance of non-pharmacological interventions that prevent or diminish cognitive decline in healthy aging.
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Affiliation(s)
- Jorge Almeida
- Proaction Lab, Faculdade de Psicologia e de Ciências da Educação, Universidade de Coimbra, Coimbra, Portugal.
- CINEICC, Faculdade de Psicologia e de Ciências da Educação, Universidade de Coimbra, Coimbra, Portugal.
| | - Ana R Martins
- Proaction Lab, Faculdade de Psicologia e de Ciências da Educação, Universidade de Coimbra, Coimbra, Portugal
| | - Lénia Amaral
- Proaction Lab, Faculdade de Psicologia e de Ciências da Educação, Universidade de Coimbra, Coimbra, Portugal
- CINEICC, Faculdade de Psicologia e de Ciências da Educação, Universidade de Coimbra, Coimbra, Portugal
- Department of Neuroscience, Georgetown University Medical Center, Washington, USA
| | - Daniela Valério
- Proaction Lab, Faculdade de Psicologia e de Ciências da Educação, Universidade de Coimbra, Coimbra, Portugal
- CINEICC, Faculdade de Psicologia e de Ciências da Educação, Universidade de Coimbra, Coimbra, Portugal
| | - Qasim Bukhari
- Proaction Lab, Faculdade de Psicologia e de Ciências da Educação, Universidade de Coimbra, Coimbra, Portugal
- CINEICC, Faculdade de Psicologia e de Ciências da Educação, Universidade de Coimbra, Coimbra, Portugal
| | - Guilherme Schu
- Proaction Lab, Faculdade de Psicologia e de Ciências da Educação, Universidade de Coimbra, Coimbra, Portugal
- CINEICC, Faculdade de Psicologia e de Ciências da Educação, Universidade de Coimbra, Coimbra, Portugal
| | - Joana Nogueira
- CINEICC, Faculdade de Psicologia e de Ciências da Educação, Universidade de Coimbra, Coimbra, Portugal
- Psychological Assessment and Psychometrics Laboratory, Faculdade de Psicologia e de Ciências da Educação, Universidade de Coimbra, Coimbra, Portugal
| | - Mónica Spínola
- CINEICC, Faculdade de Psicologia e de Ciências da Educação, Universidade de Coimbra, Coimbra, Portugal
- Psychological Assessment and Psychometrics Laboratory, Faculdade de Psicologia e de Ciências da Educação, Universidade de Coimbra, Coimbra, Portugal
- NOVA LINCS, University of Madeira, Caminho da Penteada, 9020-105, Funchal, Portugal
| | - Ghazaleh Soleimani
- Department of Biomedical Engineering, Amirkabir University of Technology (Tehran Polytechnic), Tehran, Iran
- Department of Psychiatry, University of Minnesota, Minneapolis, USA
| | | | - Ana R Silva
- CINEICC, Faculdade de Psicologia e de Ciências da Educação, Universidade de Coimbra, Coimbra, Portugal
- Psychological Assessment and Psychometrics Laboratory, Faculdade de Psicologia e de Ciências da Educação, Universidade de Coimbra, Coimbra, Portugal
| | - Felipe Fregni
- Spaulding Neuromodulation Center, Department of Physical Medicine & Rehabilitation, Spaulding Rehabilitation Hospital and Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Marcel Simis
- Faculdade de Medicina, Hospital das Clinicas HCFMUSP, Universidade de São Paulo, São Paulo, Brazil
| | - Mário Simões
- CINEICC, Faculdade de Psicologia e de Ciências da Educação, Universidade de Coimbra, Coimbra, Portugal
- Psychological Assessment and Psychometrics Laboratory, Faculdade de Psicologia e de Ciências da Educação, Universidade de Coimbra, Coimbra, Portugal
| | - André Peres
- Proaction Lab, Faculdade de Psicologia e de Ciências da Educação, Universidade de Coimbra, Coimbra, Portugal
- CINEICC, Faculdade de Psicologia e de Ciências da Educação, Universidade de Coimbra, Coimbra, Portugal
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28
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Hadjiabadi D, Soltesz I. From single-neuron dynamics to higher-order circuit motifs in control and pathological brain networks. J Physiol 2023; 601:3011-3024. [PMID: 35815823 PMCID: PMC10655857 DOI: 10.1113/jp282749] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Accepted: 06/27/2022] [Indexed: 11/08/2022] Open
Abstract
The convergence of advanced single-cell in vivo functional imaging techniques, computational modelling tools and graph-based network analytics has heralded new opportunities to study single-cell dynamics across large-scale networks, providing novel insights into principles of brain communication and pointing towards potential new strategies for treating neurological disorders. A major recent finding has been the identification of unusually richly connected hub cells that have capacity to synchronize networks and may also be critical in network dysfunction. While hub neurons are traditionally defined by measures that consider solely the number and strength of connections, novel higher-order graph analytics now enables the mining of massive networks for repeating subgraph patterns called motifs. As an illustration of the power offered by higher-order analysis of neuronal networks, we highlight how recent methodological advances uncovered a new functional cell type, the superhub, that is predicted to play a major role in regulating network dynamics. Finally, we discuss open questions that will be critical for assessing the importance of higher-order cellular-scale network analytics in understanding brain function in health and disease.
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Affiliation(s)
- Darian Hadjiabadi
- Department of Neurosurgery, Stanford University, Stanford, CA 94305, USA
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
| | - Ivan Soltesz
- Department of Neurosurgery, Stanford University, Stanford, CA 94305, USA
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29
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Lenz M, Eichler A, Kruse P, Galanis C, Kleidonas D, Andrieux G, Boerries M, Jedlicka P, Müller U, Deller T, Vlachos A. The Amyloid Precursor Protein Regulates Synaptic Transmission at Medial Perforant Path Synapses. J Neurosci 2023; 43:5290-5304. [PMID: 37369586 PMCID: PMC10359033 DOI: 10.1523/jneurosci.1824-22.2023] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2022] [Revised: 05/20/2023] [Accepted: 05/24/2023] [Indexed: 06/29/2023] Open
Abstract
The perforant path provides the primary cortical excitatory input to the hippocampus. Because of its important role in information processing and coding, entorhinal projections to the dentate gyrus have been studied in considerable detail. Nevertheless, synaptic transmission between individual connected pairs of entorhinal stellate cells and dentate granule cells remains to be characterized. Here, we have used mouse organotypic entorhino-hippocampal tissue cultures of either sex, in which the entorhinal cortex (EC) to dentate granule cell (GC; EC-GC) projection is present, and EC-GC pairs can be studied using whole-cell patch-clamp recordings. By using cultures of wild-type mice, the properties of EC-GC synapses formed by afferents from the lateral and medial entorhinal cortex were compared, and differences in short-term plasticity were identified. As the perforant path is severely affected in Alzheimer's disease, we used tissue cultures of amyloid precursor protein (APP)-deficient mice to examine the role of APP at this synapse. APP deficiency altered excitatory neurotransmission at medial perforant path synapses, which was accompanied by transcriptomic and ultrastructural changes. Moreover, presynaptic but not postsynaptic APP deletion through the local injection of Cre-expressing adeno-associated viruses in conditional APPflox/flox tissue cultures increased the neurotransmission efficacy at perforant path synapses. In summary, these data suggest a physiological role for presynaptic APP at medial perforant path synapses that may be adversely affected under altered APP processing conditions.SIGNIFICANCE STATEMENT The hippocampus receives input from the entorhinal cortex via the perforant path. These projections to hippocampal dentate granule cells are of utmost importance for learning and memory formation. Although there is detailed knowledge about perforant path projections, the functional synaptic properties at the level of individual connected pairs of neurons are not well understood. In this study, we investigated the role of APP in mediating functional properties and transmission rules in individually connected neurons using paired whole-cell patch-clamp recordings and genetic tools in organotypic tissue cultures. Our results show that presynaptic APP expression limits excitatory neurotransmission via the perforant path, which could be compromised in pathologic conditions such as Alzheimer's disease.
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Affiliation(s)
- Maximilian Lenz
- Department of Neuroanatomy, Institute of Anatomy and Cell Biology, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany
- Hannover Medical School, Institute of Neuroanatomy and Cell Biology, 30625 Hannover, Germany
| | - Amelie Eichler
- Department of Neuroanatomy, Institute of Anatomy and Cell Biology, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany
| | - Pia Kruse
- Department of Neuroanatomy, Institute of Anatomy and Cell Biology, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany
| | - Christos Galanis
- Department of Neuroanatomy, Institute of Anatomy and Cell Biology, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany
| | - Dimitrios Kleidonas
- Department of Neuroanatomy, Institute of Anatomy and Cell Biology, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany
- Spemann Graduate School of Biology and Medicine, University of Freiburg, 79104 Freiburg, Germany
- Faculty of Biology, University of Freiburg, 79104 Freiburg, Germany
| | - Geoffroy Andrieux
- Institute of Medical Bioinformatics and Systems Medicine, Medical Center, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany
| | - Melanie Boerries
- Institute of Medical Bioinformatics and Systems Medicine, Medical Center, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany
- German Cancer Consortium, German Cancer Research Center, 69120 Heidelberg, Germany
| | - Peter Jedlicka
- Interdisciplinary Centre for 3Rs in Animal Research, Faculty of Medicine, Justus-Liebig-University, 35392 Giessen, Germany
- Institute of Clinical Neuroanatomy, Neuroscience Center, Goethe University Frankfurt, 60590 Frankfurt am Main, Germany
- Frankfurt Institute for Advanced Studies, 60438 Frankfurt am Main, Germany
| | - Ulrike Müller
- Institute of Pharmacy and Molecular Biotechnology, Functional Genomics, Ruprecht-Karls University Heidelberg, 69120 Heidelberg, Germany
| | - Thomas Deller
- Institute of Clinical Neuroanatomy, Neuroscience Center, Goethe University Frankfurt, 60590 Frankfurt am Main, Germany
| | - Andreas Vlachos
- Department of Neuroanatomy, Institute of Anatomy and Cell Biology, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany
- Center for Basics in Neuromodulation, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany
- Center BrainLinks-BrainTools, University of Freiburg, 79104 Freiburg, Germany
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Ledri M, Andersson M, Wickham J, Kokaia M. Optogenetics for controlling seizure circuits for translational approaches. Neurobiol Dis 2023:106234. [PMID: 37479090 DOI: 10.1016/j.nbd.2023.106234] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Revised: 07/02/2023] [Accepted: 07/19/2023] [Indexed: 07/23/2023] Open
Abstract
The advent of optogenetic tools has had a profound impact on modern neuroscience research, revolutionizing our understanding of the brain. These tools offer a remarkable ability to precisely manipulate specific groups of neurons with an unprecedented level of temporal precision, on the order of milliseconds. This breakthrough has significantly advanced our knowledge of various physiological and pathophysiological processes in the brain. Within the realm of epilepsy research, optogenetic tools have played a crucial role in investigating the contributions of different neuronal populations to the generation of seizures and hyperexcitability. By selectively activating or inhibiting specific neurons using optogenetics, researchers have been able to elucidate the underlying mechanisms and identify key players involved in epileptic activity. Moreover, optogenetic techniques have also been explored as innovative therapeutic strategies for treating epilepsy. These strategies aim to halt seizure progression and alleviate symptoms by utilizing the precise control offered by optogenetics. The application of optogenetic tools has provided valuable insights into the intricate workings of the brain during epileptic episodes. For instance, researchers have discovered how distinct interneuron populations contribute to the initiation of seizures (ictogenesis). They have also revealed how remote circuits in regions such as the cerebellum, septum, or raphe nuclei can interact with hyperexcitable networks in the hippocampus. Additionally, studies have demonstrated the potential of closed-loop systems, where optogenetics is combined with real-time monitoring, to enable precise, on-demand control of seizure activity. Despite the immense promise demonstrated by optogenetic approaches, it is important to acknowledge that many of these techniques are still in the early stages of development and have yet to reach potential clinical applications. The transition from experimental research to practical clinical use poses numerous challenges. In this review, we aim to introduce optogenetic tools, provide a comprehensive survey of their application in epilepsy research, and critically discuss their current potential and limitations in achieving successful clinical implementation for the treatment of human epilepsy. By addressing these crucial aspects, we hope to foster a deeper understanding of the current state and future prospects of optogenetics in epilepsy treatment.
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Affiliation(s)
- Marco Ledri
- Epilepsy Center, Department of Clinical Sciences Lund, Faculty of Medicine, Lund University, Sölvegatan 17, 223 62 Lund, Sweden
| | - My Andersson
- Epilepsy Center, Department of Clinical Sciences Lund, Faculty of Medicine, Lund University, Sölvegatan 17, 223 62 Lund, Sweden
| | - Jenny Wickham
- Epilepsy Center, Department of Clinical Sciences Lund, Faculty of Medicine, Lund University, Sölvegatan 17, 223 62 Lund, Sweden
| | - Merab Kokaia
- Epilepsy Center, Department of Clinical Sciences Lund, Faculty of Medicine, Lund University, Sölvegatan 17, 223 62 Lund, Sweden.
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Arshad MN, Pinto A, van Praag H, Naegele JR. Altered connectomes of adult-born granule cells following engraftment of GABAergic progenitors in the mouse hippocampus. Prog Neurobiol 2023; 226:102450. [PMID: 37061022 PMCID: PMC11351537 DOI: 10.1016/j.pneurobio.2023.102450] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Revised: 03/25/2023] [Accepted: 04/12/2023] [Indexed: 04/17/2023]
Abstract
Adult neurogenesis occurs in the dentate gyrus (DG) of the rodent hippocampus throughout life, producing new granule cells (GCs) that migrate from a stem cell niche called the subgranular zone (SGZ) into the adjacent granule cell layer (GCL). Seizures associated with temporal lobe epilepsy alter adult neurogenesis and promote the formation of hyperexcitable circuits. Stem cell therapies for treating intractable seizure disorders are based on the premise that transplantation of GABAergic interneurons will strengthen inhibitory connections within the hippocampus and reduce hyperexcitability. Grafts of medial ganglionic eminence (MGE)-derived fetal GABAergic progenitors into the DG of adult mice with pilocarpine-induced TLE have been shown to suppress spontaneous recurrent seizures. In addition, the transplanted cells formed functional inhibitory synaptic connections with hippocampal neurons, including adult-born GCs. However, it is unknown whether MGE grafts change adult-born GC connectivity. To address this question, we compared the first-order monosynaptic inputs to adult-born GCs in TLE mice with or without MGE-derived interneuron grafts. Here we show that TLE increased excitatory inputs from endogenous hippocampal, entorhinal cortex, and medial septum/diagonal band neurons onto adult-born GCs. In contrast, in TLE mice with grafts, these excitatory inputs were reduced, coinciding with transplanted GABAergic interneuron innervation of adult-born GCs. These findings indicate that GABAergic interneuron transplantation into the dentate gyrus may prevent epilepsy-associated alterations in the connectivity of adult-born GCs.
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Affiliation(s)
- Muhammad N Arshad
- Hall-Atwater Laboratory, Wesleyan University, Department of Biology, Program in Neuroscience and Behavior, Middletown, CT 06459-0170, USA
| | - Alejandro Pinto
- Stiles-Nicholson Brain Institute and Charles E. Schmidt College of Biomedical Sciences, Florida Atlantic University, Jupiter, FL 33458, USA
| | - Henriette van Praag
- Stiles-Nicholson Brain Institute and Charles E. Schmidt College of Biomedical Sciences, Florida Atlantic University, Jupiter, FL 33458, USA
| | - Janice R Naegele
- Hall-Atwater Laboratory, Wesleyan University, Department of Biology, Program in Neuroscience and Behavior, Middletown, CT 06459-0170, USA.
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Yun Y, Wang X, Xu J, Chen J, Wang X, Yang P, Qin L. Optogenetic stimulation of basal forebrain cholinergic neurons prevents neuroinflammation and neuropsychiatric manifestations in pristane induced lupus mice. BEHAVIORAL AND BRAIN FUNCTIONS : BBF 2023; 19:11. [PMID: 37322485 DOI: 10.1186/s12993-023-00213-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Accepted: 06/07/2023] [Indexed: 06/17/2023]
Abstract
BACKGROUND Neuroinflammation has been identified as one of the primary pathogenic factors of neuropsychiatric systemic lupus erythematosus (NPSLE). However, there are no dedicated treatments available in clinics to alleviate neuroinflammation in NPSLE. It has been proposed that stimulating basal forebrain (BF) cholinergic neurons may provide potent anti-inflammatory effects in several inflammatory diseases, but its potential role in NPSLE remains unexplored. This study aims to investigate whether and how stimulating BF cholinergic neurons has a protective effect on NPSLE. RESULTS Optogenetic stimulation of BF cholinergic neurons significantly ameliorated olfactory dysfunction and anxiety- and depression-like phenotype in pristane induced lupus (PIL) mice. The increased expression of adhesion molecules (P-selectin and vascular cell adhesion molecule-1 (VCAM-1)), leukocyte recruitment, blood-brain barrier (BBB) leakage were significantly decreased. Notably, the brain histopathological changes, including the elevated levels of pro-inflammatory cytokines (TNF-α, IL-6 and IL-1β), IgG deposition in the choroid plexus and lateral ventricle wall and lipofuscin accumulation in the cortical and hippocampal neurons, were also significantly attenuated. Furthermore, we confirmed the colocalization between the BF cholinergic projections and the cerebral vessels, and the expression of α7-nicotinic acetylcholine receptor (α7nAChR) on the cerebral vessels. CONCLUSION Our data indicate that stimulation of BF cholinergic neurons could play a neuroprotective role in the brain through its cholinergic anti-inflammatory effects on cerebral vessels. Therefore, this may be a promising preventive target for NPSLE.
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Affiliation(s)
- Yang Yun
- Department of Nephrology, Shengjing Hospital of China Medical University, Shenyang, China
| | - Xuejiao Wang
- Department of Physiology, China Medical University, Shenyang, China
| | - Jingyi Xu
- Department of Rheumatology and Immunology, First Affiliated Hospital of China Medical University, Shenyang, China
| | - Jingyu Chen
- Department of Physiology, China Medical University, Shenyang, China
| | - Xueru Wang
- Department of Physiology, China Medical University, Shenyang, China
| | - Pingting Yang
- Department of Rheumatology and Immunology, First Affiliated Hospital of China Medical University, Shenyang, China
| | - Ling Qin
- Department of Physiology, China Medical University, Shenyang, China.
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Stöber TM, Batulin D, Triesch J, Narayanan R, Jedlicka P. Degeneracy in epilepsy: multiple routes to hyperexcitable brain circuits and their repair. Commun Biol 2023; 6:479. [PMID: 37137938 PMCID: PMC10156698 DOI: 10.1038/s42003-023-04823-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Accepted: 04/06/2023] [Indexed: 05/05/2023] Open
Abstract
Due to its complex and multifaceted nature, developing effective treatments for epilepsy is still a major challenge. To deal with this complexity we introduce the concept of degeneracy to the field of epilepsy research: the ability of disparate elements to cause an analogous function or malfunction. Here, we review examples of epilepsy-related degeneracy at multiple levels of brain organisation, ranging from the cellular to the network and systems level. Based on these insights, we outline new multiscale and population modelling approaches to disentangle the complex web of interactions underlying epilepsy and to design personalised multitarget therapies.
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Affiliation(s)
- Tristan Manfred Stöber
- Frankfurt Institute for Advanced Studies, 60438, Frankfurt am Main, Germany
- Institute for Neural Computation, Faculty of Computer Science, Ruhr University Bochum, 44801, Bochum, Germany
- Epilepsy Center Frankfurt Rhine-Main, Department of Neurology, Goethe University, 60590, Frankfurt, Germany
| | - Danylo Batulin
- Frankfurt Institute for Advanced Studies, 60438, Frankfurt am Main, Germany
- CePTER - Center for Personalized Translational Epilepsy Research, Goethe University, 60590, Frankfurt, Germany
- Faculty of Computer Science and Mathematics, Goethe University, 60486, Frankfurt, Germany
| | - Jochen Triesch
- Frankfurt Institute for Advanced Studies, 60438, Frankfurt am Main, Germany
| | - Rishikesh Narayanan
- Cellular Neurophysiology Laboratory, Molecular Biophysics Unit, Indian Institute of Science, Bangalore, 560012, India
| | - Peter Jedlicka
- ICAR3R - Interdisciplinary Centre for 3Rs in Animal Research, Faculty of Medicine, Justus Liebig University Giessen, 35390, Giessen, Germany.
- Institute of Clinical Neuroanatomy, Neuroscience Center, Goethe University, 60590, Frankfurt am Main, Germany.
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Zhong W, Zheng W, Ji X. Spatial Distribution of Inhibitory Innervations of Excitatory Pyramidal Cells by Major Interneuron Subtypes in the Auditory Cortex. Bioengineering (Basel) 2023; 10:bioengineering10050547. [PMID: 37237617 DOI: 10.3390/bioengineering10050547] [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: 04/07/2023] [Revised: 04/26/2023] [Accepted: 04/28/2023] [Indexed: 05/28/2023] Open
Abstract
Mental disorders, characterized by the National Institute of Mental Health as disruptions in neural circuitry, currently account for 13% of the global incidence of such disorders. An increasing number of studies suggest that imbalances between excitatory and inhibitory neurons in neural networks may be a crucial mechanism underlying mental disorders. However, the spatial distribution of inhibitory interneurons in the auditory cortex (ACx) and their relationship with excitatory pyramidal cells (PCs) remain elusive. In this study, we employed a combination of optogenetics, transgenic mice, and patch-clamp recording on brain slices to investigate the microcircuit characteristics of different interneurons (PV, SOM, and VIP) and the spatial pattern of inhibitory inhibition across layers 2/3 to 6 in the ACx. Our findings revealed that PV interneurons provide the strongest and most localized inhibition with no cross-layer innervation or layer specificity. Conversely, SOM and VIP interneurons weakly regulate PC activity over a broader range, exhibiting distinct spatial inhibitory preferences. Specifically, SOM inhibitions are preferentially found in deep infragranular layers, while VIP inhibitions predominantly occur in upper supragranular layers. PV inhibitions are evenly distributed across all layers. These results suggest that the input from inhibitory interneurons to PCs manifests in unique ways, ensuring that both strong and weak inhibitory inputs are evenly dispersed throughout the ACx, thereby maintaining a dynamic excitation-inhibition balance. Our findings contribute to understanding the spatial inhibitory characteristics of PCs and inhibitory interneurons in the ACx at the circuit level, which holds significant clinical implications for identifying and targeting abnormal circuits in auditory system diseases.
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Affiliation(s)
- Wen Zhong
- School of Traditional Chinese Medicine, Southern Medical University, Guangzhou 510515, China
| | - Wenhong Zheng
- Department of Physiology, School of Basic Medical Sciences, Key Laboratory of Psychiatric Disorders of Guangdong Province, Guangdong-Hong Kong-Macao Greater Bay Area Center for Brain Science and Brain-Inspired Intelligence, Key Laboratory of Mental Health of the Ministry of Education, Southern Medical University, Guangzhou 510515, China
| | - Xuying Ji
- Department of Physiology, School of Basic Medical Sciences, Key Laboratory of Psychiatric Disorders of Guangdong Province, Guangdong-Hong Kong-Macao Greater Bay Area Center for Brain Science and Brain-Inspired Intelligence, Key Laboratory of Mental Health of the Ministry of Education, Southern Medical University, Guangzhou 510515, China
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Muellerleile J, Vnencak M, Sethi MVA, Jungenitz T, Schwarzacher SW, Jedlicka P. Increased Network Inhibition in the Dentate Gyrus of Adult Neuroligin-4 Knock-Out Mice. eNeuro 2023; 10:10/4/ENEURO.0471-22.2023. [PMID: 37080762 PMCID: PMC10121080 DOI: 10.1523/eneuro.0471-22.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Revised: 03/01/2023] [Accepted: 03/12/2023] [Indexed: 04/22/2023] Open
Abstract
Loss-of-function mutations in neuroligin-4 (Nlgn4), a member of the neuroligin family of postsynaptic adhesion proteins, cause autism spectrum disorder in humans. Nlgn4 knockout (KO) in mice leads to social behavior deficits and complex alterations of synaptic inhibition or excitation, depending on the brain region. In the present work, we comprehensively analyzed synaptic function and plasticity at the cellular and network levels in hippocampal dentate gyrus of Nlgn4 KO mice. Compared with wild-type littermates, adult Nlgn4 KO mice exhibited increased paired-pulse inhibition of dentate granule cell population spikes, but no impairments in excitatory synaptic transmission or short-term and long-term plasticity in vivo In vitro patch-clamp recordings in neonatal organotypic entorhino-hippocampal slice cultures from Nlgn4 KO and wild-type littermates revealed no significant differences in excitatory or inhibitory synaptic transmission, homeostatic synaptic plasticity, and passive electrotonic properties in dentate granule cells, suggesting that the increased inhibition in vivo is the result of altered network activity in the adult Nlgn4 KO. A comparison with prior studies on Nlgn 1-3 knock-out mice reveals that each of the four neuroligins exerts a characteristic effect on both intrinsic cellular and network activity in the dentate gyrus in vivo.
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Affiliation(s)
- Julia Muellerleile
- Institute of Clinical Neuroanatomy, Neuroscience Center, Goethe University Frankfurt, 60590 Frankfurt am Main, Germany
- Faculty of Biosciences, Goethe University Frankfurt, 60439 Frankfurt am Main, Germany
| | - Matej Vnencak
- Institute of Clinical Neuroanatomy, Neuroscience Center, Goethe University Frankfurt, 60590 Frankfurt am Main, Germany
| | - Mohammad Valeed Ahmed Sethi
- Institute of Clinical Neuroanatomy, Neuroscience Center, Goethe University Frankfurt, 60590 Frankfurt am Main, Germany
| | - Tassilo Jungenitz
- Institute of Clinical Neuroanatomy, Neuroscience Center, Goethe University Frankfurt, 60590 Frankfurt am Main, Germany
| | - Stephan W Schwarzacher
- Institute of Clinical Neuroanatomy, Neuroscience Center, Goethe University Frankfurt, 60590 Frankfurt am Main, Germany
| | - Peter Jedlicka
- Institute of Clinical Neuroanatomy, Neuroscience Center, Goethe University Frankfurt, 60590 Frankfurt am Main, Germany
- Faculty of Medicine, Justus-Liebig-University Giessen, 35392 Giessen, Germany
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Kravchenko JA, Goldberg EM, Mattis J. Optogenetic and chemogenetic manipulation of seizure threshold in mice. STAR Protoc 2023; 4:102019. [PMID: 36640370 PMCID: PMC9846020 DOI: 10.1016/j.xpro.2022.102019] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Revised: 12/07/2022] [Accepted: 12/23/2022] [Indexed: 01/15/2023] Open
Abstract
Here, we present a protocol using optogenetics or chemogenetics to assess the neuronal circuits contributing to seizure initiation. Both approaches allow for targeted control of neuronal populations in vivo and can be combined with experimental manipulations to acutely induce seizures in rodent models. We describe how to (1) introduce and (2) activate optogenetic or chemogenetic actuators while (3) inducing seizures via hyperthermia in a mouse model of epilepsy. This protocol can be adapted for use in other induced seizure models. For complete details on the use and execution of this protocol, please refer to Mattis et al. (2022).1.
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Affiliation(s)
- Julia A Kravchenko
- Department of Neurology, University of Michigan Medical Center, Ann Arbor, MI 48109, USA.
| | - Ethan M Goldberg
- Division of Neurology, Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; Department of Neurology, The University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA; Department of Neuroscience, The University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Joanna Mattis
- Department of Neurology, University of Michigan Medical Center, Ann Arbor, MI 48109, USA; Neuroscience Graduate Program, University of Michigan Medical Center, Ann Arbor, MI 48109, USA.
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37
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Goldenberg AM, Schmidt S, Mitelman R, Levy DR, Prigge M, Katz Y, Yizhar O, Beck H, Lampl I. Localized chemogenetic silencing of inhibitory neurons: a novel mouse model of focal cortical epileptic activity. Cereb Cortex 2023; 33:2838-2856. [PMID: 35788286 DOI: 10.1093/cercor/bhac245] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Revised: 05/17/2022] [Accepted: 05/18/2022] [Indexed: 11/13/2022] Open
Abstract
Focal cortical epilepsies are frequently refractory to available anticonvulsant drug therapies. One key factor contributing to this state is the limited availability of animal models that allow to reliably study focal cortical seizures and how they recruit surrounding brain areas in vivo. In this study, we selectively expressed the inhibitory chemogenetic receptor, hM4D, in GABAergic neurons in focal cortical areas using viral gene transfer. GABAergic silencing using Clozapine-N-Oxide (CNO) demonstrated reliable induction of local epileptiform events in the electroencephalogram signal of awake freely moving mice. Anesthetized mice experiments showed consistent induction of focal epileptiform-events in both the barrel cortex (BC) and the medial prefrontal cortex (mPFC), accompanied by high-frequency oscillations, a known characteristic of human seizures. Epileptiform-events showed propagation indication with favored propagation pathways: from the BC on 1 hemisphere to its counterpart and from the BC to the mPFC, but not vice-versa. Lastly, sensory whisker-pad stimulation evoked BC epileptiform events post-CNO, highlighting the potential use of this model in studying sensory-evoked seizures. Combined, our results show that targeted chemogenetic inhibition of GABAergic neurons using hM4D can serve as a novel, versatile, and reliable model of focal cortical epileptic activity suitable for systematically studying cortical ictogenesis in different cortical areas.
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Affiliation(s)
- Adi Miriam Goldenberg
- Department of Brain Sciences, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Sarah Schmidt
- Institute for Experimental Epileptology and Cognition Research, Life and Brain Center, University of Bonn, Bonn 53105, Germany
| | - Rea Mitelman
- Department of Brain Sciences, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Dana Rubi Levy
- Department of Brain Sciences, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Matthias Prigge
- Department of Brain Sciences, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Yonatan Katz
- Department of Brain Sciences, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Ofer Yizhar
- Department of Brain Sciences, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Heinz Beck
- Institute for Experimental Epileptology and Cognition Research, Life and Brain Center, University of Bonn, Bonn 53105, Germany
| | - Ilan Lampl
- Department of Brain Sciences, Weizmann Institute of Science, Rehovot 7610001, Israel
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Lafourcade CA, Sparks FT, Bordey A, Wyneken U, Mohammadi MH. Cannabinoid regulation of neurons in the dentate gyrus during epileptogenesis: Role of CB1R-associated proteins and downstream pathways. Epilepsia 2023. [PMID: 36869624 DOI: 10.1111/epi.17569] [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: 10/11/2022] [Revised: 02/27/2023] [Accepted: 03/01/2023] [Indexed: 03/05/2023]
Abstract
The hippocampal formation plays a central role in the development of temporal lobe epilepsy (TLE), a disease characterized by recurrent, unprovoked epileptic discharges. TLE is a neurologic disorder characterized by acute long-lasting seizures (i.e., abnormal electrical activity in the brain) or seizures that occur in close proximity without recovery, typically after a brain injury or status epilepticus. After status epilepticus, epileptogenic hyperexcitability develops gradually over the following months to years, resulting in the emergence of chronic, recurrent seizures. Acting as a filter or gate, the hippocampal dentate gyrus (DG) normally prevents excessive excitation from propagating through the hippocampus, and is considered a critical region in the progression of epileptogenesis in pathological conditions. Importantly, lipid-derived endogenous cannabinoids (endocannabinoids), which are produced on demand as retrograde messengers, are central regulators of neuronal activity in the DG circuit. In this review, we summarize recent findings concerning the role of the DG in controlling hyperexcitability and propose how DG regulation by cannabinoids (CBs) could provide avenues for therapeutic interventions. We also highlight possible pathways and manipulations that could be relevant for the control of hyperexcitation. The use of CB compounds to treat epilepsies is controversial, as anecdotal evidence is not always validated by clinical trials. Recent publications shed light on the importance of the DG as a region regulating incoming hippocampal excitability during epileptogenesis. We review recent findings concerning the modulation of the hippocampal DG circuitry by CBs and discuss putative underlying pathways. A better understanding of the mechanisms by which CBs exert their action during seizures may be useful to improve therapies.
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Affiliation(s)
- Carlos A Lafourcade
- Department of Biological Sciences, Xi'an Jiaotong-Liverpool University, Suzhou, China
| | - Fraser T Sparks
- Department of Neuroscience, Columbia University, New York, New York, USA.,Current: Regeneron Pharmaceuticals, Tarrytown, New York, USA
| | - Angelique Bordey
- Department of Neurosurgery, Yale School of Medicine, New Haven, Connecticut, USA
| | - Ursula Wyneken
- Centro de Investigación e Innovación Biomédica, Laboratorio de Neurociencias, Universidad de Los Andes, Santiago, Chile.,Center of Interventional Medicine for Precision and Advanced Cellular Therapy, Santiago, Chile
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Westenbroek R, Kaplan J, Viray K, Stella N. The serine hydrolase ABHD6 controls survival and thermally induced seizures in a mouse model of Dravet syndrome. Neurobiol Dis 2023; 180:106099. [PMID: 36990366 DOI: 10.1016/j.nbd.2023.106099] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2022] [Revised: 03/03/2023] [Accepted: 03/22/2023] [Indexed: 03/29/2023] Open
Abstract
Evidence suggests that inhibition of α/β hydrolase-domain containing 6 (ABHD6) reduces seizures; however, the molecular mechanism of this therapeutic response remains unknown. We discovered that heterozygous expression of Abhd6 (Abhd6+/-) significantly reduced the premature lethality of Scn1a+/- mouse pups, a genetic mouse model of Dravet Syndrome (DS). Both Abhd6+/- mutation and pharmacological inhibition of ABHD6 reduced the duration and incidence of thermally induced seizures in Scn1a+/- pups. Mechanistically, the in vivo anti-seizure response resulting from ABHD6 inhibition is mediated by potentiation of gamma-aminobutyric acid receptors Type-A (GABAAR). Brain slice electrophysiology showed that blocking ABHD6 potentiates extrasynaptic (tonic) GABAAR currents that reduce dentate granule cell excitatory output without affecting synaptic (phasic) GABAAR currents. Our results unravel an unexpected mechanistic link between ABHD6 activity and extrasynaptic GABAAR currents that controls hippocampal hyperexcitability in a genetic mouse model of DS. BRIEF SUMMARY: This study provides the first evidence for a mechanistic link between ABHD6 activity and the control of extrasynaptic GABAAR currents that controls hippocampal hyperexcitability in a genetic mouse model of Dravet Syndrome and can be targeted to dampened seizures.
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Affiliation(s)
- Ruth Westenbroek
- Department of Pharmacology, University of Washington School of Medicine, Seattle, WA 98195, USA
| | - Joshua Kaplan
- Department of Pharmacology, University of Washington School of Medicine, Seattle, WA 98195, USA; Department of Psychology, Western Washington University, Bellingham, WA 98225, USA
| | - Katie Viray
- Department of Pharmacology, University of Washington School of Medicine, Seattle, WA 98195, USA
| | - Nephi Stella
- Department of Pharmacology, University of Washington School of Medicine, Seattle, WA 98195, USA; Department of Psychiatry and Behavioral Sciences, University of Washington School of Medicine, Seattle, WA 98195, USA.
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Stieve BJ, Smith MM, Krook-Magnuson E. LINCs Are Vulnerable to Epileptic Insult and Fail to Provide Seizure Control via On-Demand Activation. eNeuro 2023; 10:ENEURO.0195-22.2022. [PMID: 36725340 PMCID: PMC9933934 DOI: 10.1523/eneuro.0195-22.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Revised: 12/13/2022] [Accepted: 12/19/2022] [Indexed: 02/03/2023] Open
Abstract
Temporal lobe epilepsy (TLE) is notoriously pharmacoresistant, and identifying novel therapeutic targets for controlling seizures is crucial. Long-range inhibitory neuronal nitric oxide synthase-expressing cells (LINCs), a population of hippocampal neurons, were recently identified as a unique source of widespread inhibition in CA1, able to elicit both GABAA-mediated and GABAB-mediated postsynaptic inhibition. We therefore hypothesized that LINCs could be an effective target for seizure control. LINCs were optogenetically activated for on-demand seizure intervention in the intrahippocampal kainate (KA) mouse model of chronic TLE. Unexpectedly, LINC activation at 1 month post-KA did not substantially reduce seizure duration in either male or female mice. We tested two different sets of stimulation parameters, both previously found to be effective with on-demand optogenetic approaches, but neither was successful. Quantification of LINCs following intervention revealed a substantial reduction of LINC numbers compared with saline-injected controls. We also observed a decreased number of LINCs when the site of initial insult (i.e., KA injection) was moved to the amygdala [basolateral amygdala (BLA)-KA], and correspondingly, no effect of light delivery on BLA-KA seizures. This indicates that LINCs may be a vulnerable population in TLE, regardless of the site of initial insult. To determine whether long-term circuitry changes could influence outcomes, we continued testing once a month for up to 6 months post-KA. However, at no time point did LINC activation provide meaningful seizure suppression. Altogether, our results suggest that LINCs are not a promising target for seizure inhibition in TLE.
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Affiliation(s)
- Bethany J Stieve
- Graduate Program in Neuroscience, University of Minnesota, Minneapolis, Minnesota 55455
| | - Madison M Smith
- Department of Neuroscience, University of Minnesota, Minneapolis, Minnesota 55455
| | - Esther Krook-Magnuson
- Graduate Program in Neuroscience, University of Minnesota, Minneapolis, Minnesota 55455
- Department of Neuroscience, University of Minnesota, Minneapolis, Minnesota 55455
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Stella N. THC and CBD: Similarities and differences between siblings. Neuron 2023; 111:302-327. [PMID: 36638804 PMCID: PMC9898277 DOI: 10.1016/j.neuron.2022.12.022] [Citation(s) in RCA: 16] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Revised: 09/14/2022] [Accepted: 12/13/2022] [Indexed: 01/13/2023]
Abstract
Δ9-tetrahydrocannabinol (THC) and its sibling, cannabidiol (CBD), are produced by the same Cannabis plant and have similar chemical structures but differ dramatically in their mechanisms of action and effects on brain functions. Both THC and CBD exhibit promising therapeutic properties; however, impairments and increased incidence of mental health diseases are associated with acute and chronic THC use, respectively, and significant side effects are associated with chronic use of high-dose CBD. This review covers recent molecular and preclinical discoveries concerning the distinct mechanisms of action and bioactivities of THC and CBD and their impact on human behavior and diseases. These discoveries provide a foundation for the development of cannabinoid-based therapeutics for multiple devastating diseases and to assure their safe use in the growing legal market of Cannabis-based products.
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Affiliation(s)
- Nephi Stella
- Department of Pharmacology, Department Psychiatry and Behavioral Sciences, Center for Cannabis Research, Center for the Neurobiology of Addiction, Pain, and Emotion, University of Washington School of Medicine, Seattle, WA 98195, USA
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mTORC2 Inhibition Improves Morphological Effects of PTEN Loss, But Does Not Correct Synaptic Dysfunction or Prevent Seizures. J Neurosci 2023; 43:827-845. [PMID: 36526374 PMCID: PMC9899090 DOI: 10.1523/jneurosci.1354-22.2022] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Revised: 11/29/2022] [Accepted: 12/12/2022] [Indexed: 12/23/2022] Open
Abstract
Hyperactivation of PI3K/PTEN-mTOR signaling during neural development is associated with focal cortical dysplasia (FCD), autism, and epilepsy. mTOR can signal through two major hubs, mTORC1 and mTORC2, both of which are hyperactive following PTEN loss of function (LOF). Here, we tested the hypothesis that genetic inactivation of the mTORC2 complex via deletion of Rictor is sufficient to rescue morphologic and electrophysiological abnormalities in the dentate gyrus caused by PTEN loss, as well as generalized seizures. An established, early postnatal mouse model of PTEN loss in male and female mice showed spontaneous seizures that were not prevented by mTORC2 inactivation. This lack of rescue occurred despite the normalization or amelioration of many morphologic and electrophysiological phenotypes. However, increased excitatory connectivity proximal to dentate gyrus granule neuron somas was not normalized by mTORC2 inactivation. Further studies demonstrated that, although mTORC2 inactivation largely rescued the dendritic arbor overgrowth caused by PTEN LOF, it increased synaptic strength and caused additional impairments of presynaptic function. These results suggest that a constrained increase in excitatory connectivity and co-occurring synaptic dysfunction is sufficient to generate seizures downstream of PTEN LOF, even in the absence of characteristic changes in morphologic properties.SIGNIFICANCE STATEMENT Homozygous deletion of the Pten gene in neuronal subpopulations in the mouse serves as a valuable model of epilepsy caused by mTOR hyperactivation. To better understand the physiological mechanisms downstream of Pten loss that cause epilepsy, as well as the therapeutic potential of targeted gene therapies, we tested whether genetic inactivation of the mTORC2 complex could improve the cellular, synaptic, and in vivo effects of Pten loss in the dentate gyrus. We found that mTORC2 inhibition improved or rescued all morphologic effects of Pten loss in the dentate gyrus, but synaptic changes and seizures persisted. These data suggest that synaptic dysfunction can drive epilepsy caused by hyperactivation of PI3K/PTEN-mTOR, and that future therapies should focus on this mechanistic link.
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Acharya AR, Larsen LE, Delbeke J, Wadman WJ, Vonck K, Meurs A, Boon P, Raedt R. In vivo inhibition of epileptiform afterdischarges in rat hippocampus by light-activated chloride channel, stGtACR2. CNS Neurosci Ther 2022; 29:907-916. [PMID: 36482869 PMCID: PMC9928558 DOI: 10.1111/cns.14029] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Revised: 10/31/2022] [Accepted: 11/01/2022] [Indexed: 12/13/2022] Open
Abstract
AIMS The blue light-sensitive chloride-conducting opsin, stGtACR2, provides potent optogenetic silencing of neurons. The present study investigated whether activation of stGtACR2 in granule cells of the dentate gyrus (DG) inhibits epileptic afterdischarges in a rat model. METHODS Rats were bilaterally injected with 0.9 μl of AAV2/7-CaMKIIα-stGtACR2-fusionred in the DG. Three weeks later, afterdischarges were recorded from the DG by placing an optrode at the injection site and a stimulation electrode in the perforant path (PP). Afterdischarges were evoked every 10 min by unilateral electrical stimulation of the PP (20 Hz, 10 s). During every other afterdischarge, the DG was illuminated for 5 or 30 s, first ipsilaterally and then bilaterally to the PP stimulation. The line length metric of the afterdischarges was compared between illumination conditions. RESULTS Ipsilateral stGtACR2 activation during afterdischarges decreased the local field potential line length only during illumination and specifically at the illuminated site but did not reduce afterdischarge duration. Bilateral illumination did not terminate the afterdischarges. CONCLUSION Optogenetic inhibition of excitatory neurons using the blue-light sensitive chloride channel stGtACR2 reduced the amplitude of electrically induced afterdischarges in the DG at the site of illumination, but this local inhibitory effect was insufficient to reduce the duration of the afterdischarge.
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Affiliation(s)
- Anirudh R. Acharya
- 4BRAIN Team, Department of Head and Skin, Faculty of Medicine and Health SciencesGhent UniversityGhentBelgium
| | - Lars Emil Larsen
- 4BRAIN Team, Department of Head and Skin, Faculty of Medicine and Health SciencesGhent UniversityGhentBelgium
| | - Jean Delbeke
- 4BRAIN Team, Department of Head and Skin, Faculty of Medicine and Health SciencesGhent UniversityGhentBelgium
| | - Wytse J. Wadman
- 4BRAIN Team, Department of Head and Skin, Faculty of Medicine and Health SciencesGhent UniversityGhentBelgium
| | - Kristl Vonck
- 4BRAIN Team, Department of Head and Skin, Faculty of Medicine and Health SciencesGhent UniversityGhentBelgium
| | - Alfred Meurs
- 4BRAIN Team, Department of Head and Skin, Faculty of Medicine and Health SciencesGhent UniversityGhentBelgium
| | - Paul Boon
- 4BRAIN Team, Department of Head and Skin, Faculty of Medicine and Health SciencesGhent UniversityGhentBelgium
| | - Robrecht Raedt
- 4BRAIN Team, Department of Head and Skin, Faculty of Medicine and Health SciencesGhent UniversityGhentBelgium
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Barker-Haliski M, Pitsch J, Galanopoulou AS, Köhling R. A companion to the preclinical common data elements for phenotyping seizures and epilepsy in rodent models. A report of the TASK3-WG1C: Phenotyping working group of the ILAE/AES joint translational task force. Epilepsia Open 2022. [PMID: 36461665 DOI: 10.1002/epi4.12676] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Accepted: 05/23/2022] [Indexed: 12/04/2022] Open
Abstract
Epilepsy is a heterogeneous disorder characterized by spontaneous seizures and behavioral comorbidities. The underlying mechanisms of seizures and epilepsy across various syndromes lead to diverse clinical presentation and features. Similarly, animal models of epilepsy arise from numerous dissimilar inciting events. Preclinical seizure and epilepsy models can be evoked through many different protocols, leaving the phenotypic reporting subject to diverse interpretations. Serendipity can also play an outsized role in uncovering novel drivers of seizures or epilepsy, with some investigators even stumbling into epilepsy research because of a new genetic cross or unintentional drug effect. The heightened emphasis on rigor and reproducibility in preclinical research, including that which is conducted for epilepsy, underscores the need for standardized phenotyping strategies. To address this goal as part of the TASK3-WG1C Working Group of the International League Against Epilepsy (ILAE)/American Epilepsy Society (AES) Joint Translational Task Force, we developed a case report form (CRF) to describe the common data elements (CDEs) necessary for the phenotyping of seizure-like behaviors in rodents. This companion manuscript describes the use of the proposed CDEs and CRF for the visual, behavioral phenotyping of seizure-like behaviors. These phenotyping CDEs and accompanying CRF can be used in parallel with video-electroencephalography (EEG) studies or as a first visual screen to determine whether a model manifests seizure-like behaviors before utilizing more specialized diagnostic tests, like video-EEG. Systematic logging of seizure-like behaviors may help identify models that could benefit from more specialized diagnostic tests to determine whether these are epileptic seizures, such as video-EEG.
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Affiliation(s)
- Melissa Barker-Haliski
- Department of Pharmacy, School of Pharmacy, University of Washington, Seattle, Washington, USA
| | - Julika Pitsch
- Department of Epileptology, University Hospital Bonn, Bonn, Germany
| | - Aristea S Galanopoulou
- Saul R. Korey Department of Neurology, Isabelle Rapin Division of Child Neurology, Laboratory of Developmental Epilepsy, Albert Einstein College of Medicine, Bronx, New York, USA
- Dominick P Purpura Department of Neuroscience, Isabelle Rapin Division of Child Neurology, Laboratory of Developmental Epilepsy, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Rüdiger Köhling
- Oscar-Langendorff-Institut für Physiologie, Universitätsmedizin Rostock, Rostock, Germany
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Loss of Rai1 enhances hippocampal excitability and epileptogenesis in mouse models of Smith-Magenis syndrome. Proc Natl Acad Sci U S A 2022; 119:e2210122119. [PMID: 36256819 PMCID: PMC9618093 DOI: 10.1073/pnas.2210122119] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Smith–Magenis syndrome (SMS) is a neurodevelopmental disorder associated with autism and epileptic seizures. SMS is caused by losing one copy of the gene encoding retinoic acid induced 1 (RAI1), a ubiquitously expressed transcriptional regulator. To pinpoint brain regions and cell types contributing to neuronal hyperexcitability in SMS, we combined electrophysiology and three-dimensional imaging of Fos expression in the intact mouse brain. We found that Rai1-deficient hippocampal dentate gyrus granule cells (dGCs) show increased intrinsic excitability and enhanced glutamatergic synaptic transmission. Our findings indicate that Rai1 safeguards the hippocampal network from hyperexcitability and could help explain abnormal brain activity in SMS. Hyperexcitability of brain circuits is a common feature of autism spectrum disorders (ASDs). Genetic deletion of a chromatin-binding protein, retinoic acid induced 1 (RAI1), causes Smith–Magenis syndrome (SMS). SMS is a syndromic ASD associated with intellectual disability, autistic features, maladaptive behaviors, overt seizures, and abnormal electroencephalogram (EEG) patterns. The molecular and neural mechanisms underlying abnormal brain activity in SMS remain unclear. Here we show that panneural Rai1 deletions in mice result in increased seizure susceptibility and prolonged hippocampal seizure duration in vivo and increased dentate gyrus population spikes ex vivo. Brain-wide mapping of neuronal activity pinpointed selective cell types within the limbic system, including the hippocampal dentate gyrus granule cells (dGCs) that are hyperactivated by chemoconvulsant administration or sensory experience in Rai1-deficient brains. Deletion of Rai1 from glutamatergic neurons, but not from gamma-aminobutyric acidergic (GABAergic) neurons, was responsible for increased seizure susceptibility. Deleting Rai1 from the Emx1Cre-lineage glutamatergic neurons resulted in abnormal dGC properties, including increased excitatory synaptic transmission and increased intrinsic excitability. Our work uncovers the mechanism of neuronal hyperexcitability in SMS by identifying Rai1 as a negative regulator of dGC intrinsic and synaptic excitability.
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Mardones MD, Gupta K. Transcriptome Profiling of the Hippocampal Seizure Network Implicates a Role for Wnt Signaling during Epileptogenesis in a Mouse Model of Temporal Lobe Epilepsy. Int J Mol Sci 2022; 23:12030. [PMID: 36233336 PMCID: PMC9569502 DOI: 10.3390/ijms231912030] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Revised: 10/03/2022] [Accepted: 10/06/2022] [Indexed: 11/17/2022] Open
Abstract
Mesial temporal lobe epilepsy (mTLE) is a life-threatening condition characterized by recurrent hippocampal seizures. mTLE can develop after exposure to risk factors such as febrile seizure, trauma, and infection. Within the latent period between exposure and onset of epilepsy, pathological remodeling events occur that contribute to epileptogenesis. The molecular mechanisms responsible are currently unclear. We used the mouse intrahippocampal kainite model of mTLE to investigate transcriptional dysregulation in the ipsilateral and contralateral dentate gyrus (DG), representing the epileptogenic zone (EZ) and peri-ictal zone (PIZ). DG were analyzed after 3, 7, and 14 days by RNA sequencing. In both the EZ and PIZ, transcriptional dysregulation was dynamic over the epileptogenic period with early expression of genes representing cell signaling, migration, and proliferation. Canonical Wnt signaling was upregulated in the EZ and PIZ at 3 days. Expression of inflammatory genes differed between the EZ and PIZ, with early expression after 3 days in the PIZ and delayed expression after 7-14 days in the EZ. This suggests that critical gene changes occur early in the hippocampal seizure network and that Wnt signaling may play a role within the latent epileptogenic period. These findings may help to identify novel therapeutic targets that could prevent epileptogenesis.
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Affiliation(s)
- Muriel D Mardones
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Department of Neurological Surgery, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Kunal Gupta
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Department of Neurological Surgery, Indiana University School of Medicine, Indianapolis, IN 46202, USA
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Whitebirch AC, LaFrancois JJ, Jain S, Leary P, Santoro B, Siegelbaum SA, Scharfman HE. Enhanced excitability of the hippocampal CA2 region and its contribution to seizure activity in a mouse model of temporal lobe epilepsy. Neuron 2022; 110:3121-3138.e8. [PMID: 35987207 PMCID: PMC9547935 DOI: 10.1016/j.neuron.2022.07.020] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Revised: 05/26/2022] [Accepted: 07/19/2022] [Indexed: 11/25/2022]
Abstract
The hippocampal CA2 region, an area important for social memory, has been suspected to play a role in temporal lobe epilepsy (TLE) because of its resistance to degeneration observed in neighboring CA1 and CA3 regions in both humans and rodent models of TLE. However, little is known about whether alterations in CA2 properties promote seizure generation or propagation. Here, we addressed the role of CA2 using the pilocarpine-induced status epilepticus model of TLE. Ex vivo electrophysiological recordings from acute hippocampal slices revealed a set of coordinated changes that enhance CA2 PC intrinsic excitability, reduce CA2 inhibitory input, and increase CA2 excitatory output to its major CA1 synaptic target. Moreover, selective chemogenetic silencing of CA2 pyramidal cells caused a significant decrease in the frequency of spontaneous seizures measured in vivo. These findings provide the first evidence that CA2 actively contributes to TLE seizure activity and may thus be a promising therapeutic target.
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Affiliation(s)
- Alexander C Whitebirch
- Departments of Neuroscience and Pharmacology, Kavli Institute for Brain Science, Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University Irving Medical Center, New York, NY 10027, USA
| | - John J LaFrancois
- The Nathan S. Kline Institute for Psychiatric Research, Orangeburg, NY 10962, USA
| | - Swati Jain
- The Nathan S. Kline Institute for Psychiatric Research, Orangeburg, NY 10962, USA
| | - Paige Leary
- Department of Neuroscience and Physiology, New York University Langone Health, New York, NY 10016, USA
| | - Bina Santoro
- Departments of Neuroscience and Pharmacology, Kavli Institute for Brain Science, Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University Irving Medical Center, New York, NY 10027, USA
| | - Steven A Siegelbaum
- Departments of Neuroscience and Pharmacology, Kavli Institute for Brain Science, Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University Irving Medical Center, New York, NY 10027, USA.
| | - Helen E Scharfman
- Department of Child Psychiatry, New York University Langone Health, New York, NY 10016, USA; Department of Neuroscience and Physiology, New York University Langone Health, New York, NY 10016, USA; Department of Psychiatry, New York University Langone Health, New York, NY 10016, USA; The Nathan S. Kline Institute for Psychiatric Research, Orangeburg, NY 10962, USA.
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Kapur J, Long L, Dixon-Salazar T. Consequences: Bench to home. Epilepsia 2022; 63 Suppl 1:S14-S24. [PMID: 35999173 DOI: 10.1111/epi.17342] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 06/08/2022] [Accepted: 06/08/2022] [Indexed: 01/02/2023]
Abstract
Seizure clusters (also referred to as acute repetitive seizures) consist of several seizures interspersed with brief interictal periods. Seizure clusters can break down γ-aminobutyric acidergic (GABAergic) inhibition of dentate granule cells, leading to hyperactivation. Functional changes to GABAA receptors, which play a vital neuroinhibitory role, can include altered GABAA receptor subunit trafficking and cellular localization, intracellular chloride accumulation, and dysregulation of proteins critical to chloride homeostasis. A reduction in neuroinhibition and potentiation of excitatory neurotransmission in CA1 pyramidal neurons represent pathological mechanisms that underlie seizure clusters. Benzodiazepines are well-established treatments for seizure clusters; however, there remain barriers to appropriate care. At the clinical level, there is variability in seizure cluster definitions, such as the number and/or type of seizures associated with a cluster as well as the interictal duration between seizures. This can lead to delays in diagnosis and timely treatment. There are gaps in understanding between clinicians, their patients, and caregivers regarding acute treatment for seizure clusters, such as the use of rescue medications and emergency services. This lack of consensus to define seizure clusters in addition to a lack of education for appropriate treatment can affect quality of life for patients and place a greater burden on patient families and caregivers. For patients with seizure clusters, the sense of unpredictability can lead to continuous traumatic stress, during which patients and families live with a heightened level of anxiety. Clinicians can affect patient quality of life and clinical outcomes through improved seizure cluster education and treatment, such as the development and implementation of a personalized seizure action plan as well as prescriptions for suitable rescue medications indicated for seizure clusters and instructions for their proper use. In all, the combination of targeted therapy along with patient education and support can improve quality of life.
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Affiliation(s)
- Jaideep Kapur
- Department of Neurology, University of Virginia, Charlottesville, Virginia, USA
| | - Lucretia Long
- Wexner Medical Center, The Ohio State University, Columbus, Ohio, USA
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Zirotti Rosenberg A, Méndez-Ruette M, Gorziglia M, Alzerreca B, Cabello J, Kaufmann S, Rambousek L, Iturriaga Jofré A, Wyneken U, Lafourcade CA. Behavioral and Molecular Responses to Exogenous Cannabinoids During Pentylenetetrazol-Induced Convulsions in Male and Female Rats. Front Mol Neurosci 2022; 15:868583. [PMID: 36147210 PMCID: PMC9488559 DOI: 10.3389/fnmol.2022.868583] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Accepted: 05/13/2022] [Indexed: 11/13/2022] Open
Abstract
Epilepsy is a disabling, chronic brain disease,affecting ~1% of the World’s population, characterized by recurrent seizures (sudden, uncontrolled brain activity), which may manifest with motor symptoms (e.g., convulsions) or non-motor symptoms. Temporal lobe epilepsies (TLE) compromising the hippocampus are the most common form of focal epilepsies. Resistance in ~1/3 of epileptic patients to the first line of treatment, i.e., antiepileptic drugs (AEDs), has been an important motivation to seek alternative treatments. Among these, the plant Cannabis sativa (commonly known as marihuana) or compounds extracted from it (cannabinoids) have gained widespread popularity. Moreover, sex differences have been proposed in epilepsy syndromes and in cannabinoid action. In the hippocampus, cannabinoids interact with the CB1R receptor whose membrane levels are regulated by β-Arrestin2, a protein that promotes its endocytosis and causes its downregulation. In this article, we evaluate the modulatory role of WIN 55,212-2 (WIN), a synthetic exogenous cannabinoid on behavioral convulsions and on the levels of CB1R and β-Arrestin2 in female and male adolescent rats after a single injection of the proconvulsant pentylenetetrazol (PTZ). As epilepsies can have a considerable impact on synaptic proteins that regulate neuronal toxicity, plasticity, and cognition, we also measured the levels of key proteins markers of excitatory synapses, in order to examine whether exogenous cannabinoids may prevent such pathologic changes after acute seizures. We found that the exogenous administration of WIN prevented convulsions of medium severity in females and males and increased the levels of phosphorylated CaMKII in the hippocampus. Furthermore, we observed a higher degree of colocalization between CB1R and β-Arrestin2 in the granule cell layer.
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Affiliation(s)
| | - Maxs Méndez-Ruette
- Centro de investigación e innovación Biomédica (CiiB), Laboratorio de Neurociencias, Universidad de Los Andes, Santiago, Chile
| | - Mario Gorziglia
- Facultad de Medicina, Universidad de Los Andes, Santiago, Chile
| | | | - Javiera Cabello
- Facultad de Medicina, Universidad de Los Andes, Santiago, Chile
| | - Sofía Kaufmann
- Facultad de Medicina, Universidad de Los Andes, Santiago, Chile
| | - Lukas Rambousek
- Institute of Experimental Immunology, University of Zurich, Zurich, Switzerland
| | | | - Ursula Wyneken
- Facultad de Medicina, Universidad de Los Andes, Santiago, Chile
- IMPACT, Center of Interventional Medicine for Precision and Advanced Cellular Therapy, Santiago, Chile
| | - Carlos A. Lafourcade
- Department of Biological Sciences, Xi’an Jiaotong-Liverpool University (XJTLU), Suzhou, China
- *Correspondence: Carlos A. Lafourcade
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50
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Seizure-induced strengthening of a recurrent excitatory circuit in the dentate gyrus is proconvulsant. Proc Natl Acad Sci U S A 2022; 119:e2201151119. [PMID: 35930664 PMCID: PMC9371717 DOI: 10.1073/pnas.2201151119] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Epilepsy is a devastating brain disorder for which effective treatments are very limited. There is growing interest in early intervention, which requires a better mechanistic understanding of the early stages of this disorder. While diverse brain insults can lead to epileptic activity, a common cellular mechanism relies on uncontrolled recurrent excitatory activity. In the dentate gyrus, excitatory mossy cells (MCs) project extensively onto granule cells (GCs) throughout the hippocampus, thus establishing a recurrent MC-GC-MC excitatory loop. MCs are implicated in temporal lobe epilepsy, a common form of epilepsy, but their role during initial seizures (i.e., before the characteristic MC loss that occurs in late stages) is unclear. Here, we show that initial seizures acutely induced with an intraperitoneal kainic acid (KA) injection in adult mice, a well-established model that leads to experimental epilepsy, not only increased MC and GC activity in vivo but also triggered a brain-derived neurotrophic factor (BDNF)-dependent long-term potentiation (LTP) at MC-GC excitatory synapses. Moreover, in vivo induction of MC-GC LTP using MC-selective optogenetic stimulation worsened KA-induced seizures. Conversely, Bdnf genetic removal from GCs, which abolishes LTP, and selective MC silencing were both anticonvulsant. Thus, initial seizures are associated with MC-GC synaptic strengthening, which may promote later epileptic activity. Our findings reveal a potential mechanism of epileptogenesis that may help in developing therapeutic strategies for early intervention.
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