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Pereira MF, Shyti R, Testa G. In and out: Benchmarking in vitro, in vivo, ex vivo, and xenografting approaches for an integrative brain disease modeling pipeline. Stem Cell Reports 2024; 19:767-795. [PMID: 38865969 DOI: 10.1016/j.stemcr.2024.05.004] [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: 12/11/2022] [Revised: 05/09/2024] [Accepted: 05/11/2024] [Indexed: 06/14/2024] Open
Abstract
Human cellular models and their neuronal derivatives have afforded unprecedented advances in elucidating pathogenic mechanisms of neuropsychiatric diseases. Notwithstanding their indispensable contribution, animal models remain the benchmark in neurobiological research. In an attempt to harness the best of both worlds, researchers have increasingly relied on human/animal chimeras by xenografting human cells into the animal brain. Despite the unparalleled potential of xenografting approaches in the study of the human brain, literature resources that systematically examine their significance and advantages are surprisingly lacking. We fill this gap by providing a comprehensive account of brain diseases that were thus far subjected to all three modeling approaches (transgenic rodents, in vitro human lineages, human-animal xenografting) and provide a critical appraisal of the impact of xenografting approaches for advancing our understanding of those diseases and brain development. Next, we give our perspective on integrating xenografting modeling pipeline with recent cutting-edge technological advancements.
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Affiliation(s)
- Marlene F Pereira
- Department of Experimental Oncology, European Institute of Oncology IRCCS, Via Adamello 16, 20139 Milan, Italy; Department of Oncology and Hemato-Oncology, University of Milan, Via Santa Sofia 9, 20122 Milan, Italy; Neurogenomics Centre, Human Technopole, Viale Rita Levi-Montalcini 1, 20157 Milan, Italy.
| | - Reinald Shyti
- Department of Experimental Oncology, European Institute of Oncology IRCCS, Via Adamello 16, 20139 Milan, Italy; Neurogenomics Centre, Human Technopole, Viale Rita Levi-Montalcini 1, 20157 Milan, Italy.
| | - Giuseppe Testa
- Department of Experimental Oncology, European Institute of Oncology IRCCS, Via Adamello 16, 20139 Milan, Italy; Department of Oncology and Hemato-Oncology, University of Milan, Via Santa Sofia 9, 20122 Milan, Italy; Neurogenomics Centre, Human Technopole, Viale Rita Levi-Montalcini 1, 20157 Milan, Italy.
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2
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McArdle CJ, Arnone AA, Heaney CF, Raab-Graham KF. A paradoxical switch: the implications of excitatory GABAergic signaling in neurological disorders. Front Psychiatry 2024; 14:1296527. [PMID: 38268565 PMCID: PMC10805837 DOI: 10.3389/fpsyt.2023.1296527] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Accepted: 12/04/2023] [Indexed: 01/26/2024] Open
Abstract
Gamma-aminobutyric acid (GABA) is the primary inhibitory neurotransmitter in the central nervous system. In the mature brain, inhibitory GABAergic signaling is critical in maintaining neuronal homeostasis and vital human behaviors such as cognition, emotion, and motivation. While classically known to inhibit neuronal function under physiological conditions, previous research indicates a paradoxical switch from inhibitory to excitatory GABAergic signaling that is implicated in several neurological disorders. Various mechanisms have been proposed to contribute to the excitatory switch such as chloride ion dyshomeostasis, alterations in inhibitory receptor expression, and modifications in GABAergic synaptic plasticity. Of note, the hypothesized mechanisms underlying excitatory GABAergic signaling are highlighted in a number of neurodevelopmental, substance use, stress, and neurodegenerative disorders. Herein, we present an updated review discussing the presence of excitatory GABAergic signaling in various neurological disorders, and their potential contributions towards disease pathology.
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Affiliation(s)
- Colin J. McArdle
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC, United States
| | - Alana A. Arnone
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC, United States
- Department of General Surgery, Wake Forest University School of Medicine, Winston-Salem, NC, United States
| | - Chelcie F. Heaney
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC, United States
| | - Kimberly F. Raab-Graham
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC, United States
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3
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Singh A, Hadjinicolaou A, Peters JM, Salussolia CL. Treatment-Resistant Epilepsy and Tuberous Sclerosis Complex: Treatment, Maintenance, and Future Directions. Neuropsychiatr Dis Treat 2023; 19:733-748. [PMID: 37041855 PMCID: PMC10083014 DOI: 10.2147/ndt.s347327] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Accepted: 03/22/2023] [Indexed: 04/13/2023] Open
Abstract
Tuberous sclerosis complex (TSC) is a neurogenetic disorder that affects multiple organ systems, including the heart, kidneys, eyes, skin, and central nervous system. The neurologic manifestations have the highest morbidity and mortality, in particular in children. Clinically, patients with TSC often present with new-onset seizures within the first year of life. TSC-associated epilepsy is often difficult to treat and refractory to multiple antiseizure medications. Refractory TSC-associated epilepsy is associated with increased risk of neurodevelopmental comorbidities, including developmental delay, intellectual disability, autism spectrum disorder, and attention hyperactivity disorder. An increasing body of research suggests that early, effective treatment of TSC-associated epilepsy during critical neurodevelopmental periods can potentially improve cognitive outcomes. Therefore, it is important to treat TSC-associated epilepsy aggressively, whether it be with pharmacological therapy, surgical intervention, and/or neuromodulation. This review discusses current and future pharmacological treatments for TSC-associated epilepsy, as well as the importance of early surgical evaluation for refractory epilepsy in children with TSC and consideration of neuromodulatory interventions in young adults.
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Affiliation(s)
- Avantika Singh
- Division of Epilepsy and Neurophysiology, Department of Neurology, Boston Children’s Hospital and Harvard Medical School, Boston, MA, USA
| | - Aristides Hadjinicolaou
- Division of Epilepsy and Neurophysiology, Department of Neurology, Boston Children’s Hospital and Harvard Medical School, Boston, MA, USA
| | - Jurriaan M Peters
- Division of Epilepsy and Neurophysiology, Department of Neurology, Boston Children’s Hospital and Harvard Medical School, Boston, MA, USA
| | - Catherine L Salussolia
- Division of Epilepsy and Neurophysiology, Department of Neurology, Boston Children’s Hospital and Harvard Medical School, Boston, MA, USA
- F.M. Kirby Neurobiology Center, Department of Neurology, Boston Children’s Hospital and Harvard Medical School, Boston, MA, USA
- Correspondence: Catherine L Salussolia, 3 Blackfan Circle, Center for Life Sciences 14060, Boston, MA, 02115, USA, Tel +617-355-7970, Email
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Qiu Y, Sha L, Zhang X, Li G, Zhu W, Xu Q. Induction of A Disintegrin and Metalloproteinase with Thrombospondin motifs 1 by a rare variant or cognitive activities reduces hippocampal amyloid-β and consequent Alzheimer’s disease risk. Front Aging Neurosci 2022; 14:896522. [PMID: 36016856 PMCID: PMC9395645 DOI: 10.3389/fnagi.2022.896522] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Accepted: 07/15/2022] [Indexed: 11/30/2022] Open
Abstract
Amyloid-β (Aβ) derived from amyloid precursor protein (APP) hydrolysis is acknowledged as the predominant hallmark of Alzheimer’s disease (AD) that especially correlates to genetics and daily activities. In 2019, meta-analysis of AD has discovered five new risk loci among which A Disintegrin and Metalloproteinase with Thrombospondin motifs 1 (ADAMTS1) has been further suggested in 2021 and 2022. To verify the association, we re-sequenced ADAMTS1 of clinical AD samples and subsequently identified a novel rare variant c.–2067A > C with watchable relevance (whereas the P-value was not significant after adjustment). Dual-luciferase assay showed that the variant sharply stimulated ADAMTS1 expression. In addition, ADAMTS1 was also clearly induced by pentylenetetrazol-ignited neuronal activity and enriched environment (EE). Inspired by the above findings, we investigated ADAMTS1’s role in APP metabolism in vitro and in vivo. Results showed that ADAMTS1 participated in APP hydrolysis and consequently decreased Aβ generation through inhibiting β-secretase-mediated cleavage. In addition, we also verified that the hippocampal amyloid load of AD mouse model was alleviated by the introduction of ADAMTS1, and thus spatial cognition was restored as well. This study revealed the contribution of ADAMTS1 to the connection of genetic and acquired factors with APP metabolism, and its potential in reducing hippocampal amyloid and consequent risk of AD.
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Affiliation(s)
- Yunjie Qiu
- State Key Laboratory of Medical Molecular Biology, School of Basic Medicine Peking Union Medical College, Institute of Basic Medical Sciences Chinese Academy of Medical Sciences, Beijing, China
| | - Longze Sha
- State Key Laboratory of Medical Molecular Biology, School of Basic Medicine Peking Union Medical College, Institute of Basic Medical Sciences Chinese Academy of Medical Sciences, Beijing, China
- Neuroscience Center, Chinese Academy of Medical Sciences, Beijing, China
| | - Xiuneng Zhang
- State Key Laboratory of Medical Molecular Biology, School of Basic Medicine Peking Union Medical College, Institute of Basic Medical Sciences Chinese Academy of Medical Sciences, Beijing, China
| | - Guanjun Li
- State Key Laboratory of Medical Molecular Biology, School of Basic Medicine Peking Union Medical College, Institute of Basic Medical Sciences Chinese Academy of Medical Sciences, Beijing, China
| | - Wanwan Zhu
- State Key Laboratory of Medical Molecular Biology, School of Basic Medicine Peking Union Medical College, Institute of Basic Medical Sciences Chinese Academy of Medical Sciences, Beijing, China
- Neuroscience Center, Chinese Academy of Medical Sciences, Beijing, China
| | - Qi Xu
- State Key Laboratory of Medical Molecular Biology, School of Basic Medicine Peking Union Medical College, Institute of Basic Medical Sciences Chinese Academy of Medical Sciences, Beijing, China
- Neuroscience Center, Chinese Academy of Medical Sciences, Beijing, China
- *Correspondence: Qi Xu,
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Juarez-Martinez EL, van Andel DM, Sprengers JJ, Avramiea AE, Oranje B, Scheepers FE, Jansen FE, Mansvelder HD, Linkenkaer-Hansen K, Bruining H. Bumetanide Effects on Resting-State EEG in Tuberous Sclerosis Complex in Relation to Clinical Outcome: An Open-Label Study. Front Neurosci 2022; 16:879451. [PMID: 35645706 PMCID: PMC9134117 DOI: 10.3389/fnins.2022.879451] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2022] [Accepted: 04/15/2022] [Indexed: 12/05/2022] Open
Abstract
Neuronal excitation-inhibition (E/I) imbalances are considered an important pathophysiological mechanism in neurodevelopmental disorders. Preclinical studies on tuberous sclerosis complex (TSC), suggest that altered chloride homeostasis may impair GABAergic inhibition and thereby E/I-balance regulation. Correction of chloride homeostasis may thus constitute a treatment target to alleviate behavioral symptoms. Recently, we showed that bumetanide-a chloride-regulating agent-improved behavioral symptoms in the open-label study Bumetanide to Ameliorate Tuberous Sclerosis Complex Hyperexcitable Behaviors trial (BATSCH trial; Eudra-CT: 2016-002408-13). Here, we present resting-state EEG as secondary analysis of BATSCH to investigate associations between EEG measures sensitive to network-level changes in E/I balance and clinical response to bumetanide. EEGs of 10 participants with TSC (aged 8-21 years) were available. Spectral power, long-range temporal correlations (LRTC), and functional E/I ratio (fE/I) in the alpha-frequency band were compared before and after 91 days of treatment. Pre-treatment measures were compared against 29 typically developing children (TDC). EEG measures were correlated with the Aberrant Behavioral Checklist-Irritability subscale (ABC-I), the Social Responsiveness Scale-2 (SRS-2), and the Repetitive Behavior Scale-Revised (RBS-R). At baseline, TSC showed lower alpha-band absolute power and fE/I than TDC. Absolute power increased through bumetanide treatment, which showed a moderate, albeit non-significant, correlation with improvement in RBS-R. Interestingly, correlations between baseline EEG measures and clinical outcomes suggest that most responsiveness might be expected in children with network characteristics around the E/I balance point. In sum, E/I imbalances pointing toward an inhibition-dominated network are present in TSC. We established neurophysiological effects of bumetanide although with an inconclusive relationship with clinical improvement. Nonetheless, our results further indicate that baseline network characteristics might influence treatment response. These findings highlight the possible utility of E/I-sensitive EEG measures to accompany new treatment interventions for TSC. Clinical Trial Registration EU Clinical Trial Register, EudraCT 2016-002408-13 (www.clinicaltrialsregister.eu/ctr-search/trial/2016-002408-13/NL). Registered 25 July 2016.
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Affiliation(s)
- Erika L. Juarez-Martinez
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research (CNCR), Amsterdam Neuroscience, VU University Amsterdam, Amsterdam, Netherlands
- Child and Adolescent Psychiatry and Psychosocial Care, Emma Children’s Hospital, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam, Netherlands
| | - Dorinde M. van Andel
- Department of Psychiatry, UMC Utrecht Brain Center, University Medical Centre Utrecht, Utrecht, Netherlands
| | - Jan J. Sprengers
- Department of Psychiatry, UMC Utrecht Brain Center, University Medical Centre Utrecht, Utrecht, Netherlands
| | - Arthur-Ervin Avramiea
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research (CNCR), Amsterdam Neuroscience, VU University Amsterdam, Amsterdam, Netherlands
| | - Bob Oranje
- Department of Psychiatry, UMC Utrecht Brain Center, University Medical Centre Utrecht, Utrecht, Netherlands
| | - Floortje E. Scheepers
- Department of Psychiatry, UMC Utrecht Brain Center, University Medical Centre Utrecht, Utrecht, Netherlands
| | - Floor E. Jansen
- Department of Pediatric Neurology, UMC Utrecht Brain Center, University Medical Center Utrecht, Utrecht, Netherlands
| | - Huibert D. Mansvelder
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research (CNCR), Amsterdam Neuroscience, VU University Amsterdam, Amsterdam, Netherlands
| | - Klaus Linkenkaer-Hansen
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research (CNCR), Amsterdam Neuroscience, VU University Amsterdam, Amsterdam, Netherlands
| | - Hilgo Bruining
- Child and Adolescent Psychiatry and Psychosocial Care, Emma Children’s Hospital, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam, Netherlands
- Department of Psychiatry, UMC Utrecht Brain Center, University Medical Centre Utrecht, Utrecht, Netherlands
- N=You Neurodevelopmental Precision Center, Amsterdam Neuroscience, Amsterdam Reproduction and Development, Amsterdam UMC, Amsterdam, Netherlands
- Levvel, Academic Center for Child and Adolescent Psychiatry, Amsterdam, Netherlands
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6
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Roy A, Han VZ, Bard AM, Wehle DT, Smith SEP, Ramirez JM, Kalume F, Millen KJ. Non-synaptic Cell-Autonomous Mechanisms Underlie Neuronal Hyperactivity in a Genetic Model of PIK3CA-Driven Intractable Epilepsy. Front Mol Neurosci 2021; 14:772847. [PMID: 34899181 PMCID: PMC8662737 DOI: 10.3389/fnmol.2021.772847] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Accepted: 10/20/2021] [Indexed: 12/26/2022] Open
Abstract
Patients harboring mutations in the PI3K-AKT-MTOR pathway-encoding genes often develop a spectrum of neurodevelopmental disorders including epilepsy. A significant proportion remains unresponsive to conventional anti-seizure medications. Understanding mutation-specific pathophysiology is thus critical for molecularly targeted therapies. We previously determined that mouse models expressing a patient-related activating mutation in PIK3CA, encoding the p110α catalytic subunit of phosphoinositide-3-kinase (PI3K), are epileptic and acutely treatable by PI3K inhibition, irrespective of dysmorphology. Here we report the physiological mechanisms underlying this dysregulated neuronal excitability. In vivo, we demonstrate epileptiform events in the Pik3ca mutant hippocampus. By ex vivo analyses, we show that Pik3ca-driven hyperactivation of hippocampal pyramidal neurons is mediated by changes in multiple non-synaptic, cell-intrinsic properties. Finally, we report that acute inhibition of PI3K or AKT, but not MTOR activity, suppresses the intrinsic hyperactivity of the mutant neurons. These acute mechanisms are distinct from those causing neuronal hyperactivity in other AKT-MTOR epileptic models and define parameters to facilitate the development of new molecularly rational therapeutic interventions for intractable epilepsy.
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Affiliation(s)
- Achira Roy
- Neuroscience Unit, Jawaharlal Nehru Centre for Advanced Scientific Research (JNCASR), Bengaluru, India
| | - Victor Z Han
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, United States.,Department of Biology, University of Washington, Seattle, WA, United States
| | - Angela M Bard
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, United States
| | - Devin T Wehle
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, United States.,Graduate Program in Neuroscience, University of Washington, Seattle, WA, United States
| | - Stephen E P Smith
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, United States.,Department of Pediatrics, University of Washington, Seattle, WA, United States
| | - Jan-Marino Ramirez
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, United States.,Department of Pediatrics, University of Washington, Seattle, WA, United States.,Department of Neurological Surgery, University of Washington, Seattle, WA, United States.,Department of Physiology and Biophysics, University of Washington, Seattle, WA, United States
| | - Franck Kalume
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, United States.,Department of Neurological Surgery, University of Washington, Seattle, WA, United States.,Department of Pharmacology, University of Washington, Seattle, WA, United States
| | - Kathleen J Millen
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, United States.,Department of Pediatrics, University of Washington, Seattle, WA, United States
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7
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Mizuguchi M, Ohsawa M, Kashii H, Sato A. Brain Symptoms of Tuberous Sclerosis Complex: Pathogenesis and Treatment. Int J Mol Sci 2021; 22:ijms22136677. [PMID: 34206526 PMCID: PMC8268912 DOI: 10.3390/ijms22136677] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 06/16/2021] [Accepted: 06/19/2021] [Indexed: 12/12/2022] Open
Abstract
The mammalian target of the rapamycin (mTOR) system plays multiple, important roles in the brain, regulating both morphology, such as cellular size, shape, and position, and function, such as learning, memory, and social interaction. Tuberous sclerosis complex (TSC) is a congenital disorder caused by a defective suppressor of the mTOR system, the TSC1/TSC2 complex. Almost all brain symptoms of TSC are manifestations of an excessive activity of the mTOR system. Many children with TSC are afflicted by intractable epilepsy, intellectual disability, and/or autism. In the brains of infants with TSC, a vicious cycle of epileptic encephalopathy is formed by mTOR hyperactivity, abnormal synaptic structure/function, and excessive epileptic discharges, further worsening epilepsy and intellectual/behavioral disorders. Molecular target therapy with mTOR inhibitors has recently been proved to be efficacious for epilepsy in human TSC patients, and for autism in TSC model mice, indicating the possibility for pharmacological treatment of developmental synaptic disorders.
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Affiliation(s)
- Masashi Mizuguchi
- Department of Developmental Medical Sciences, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan;
- Department of Pediatrics, National Rehabilitation Center for Children with Disabilities, Itabashi-ku, Tokyo 173-0037, Japan
- Correspondence: ; Tel.: +81-3-5841-3515
| | - Maki Ohsawa
- Department of Developmental Medical Sciences, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan;
- Department of Pediatrics, National Rehabilitation Center for Children with Disabilities, Itabashi-ku, Tokyo 173-0037, Japan
| | - Hirofumi Kashii
- Department of Neuropediatrics, Tokyo Metropolitan Neurological Hospital, Fuchu, Tokyo 183-0042, Japan;
| | - Atsushi Sato
- Department of Pediatrics, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo 113-8655, Japan;
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Nguyen LH, Bordey A. Convergent and Divergent Mechanisms of Epileptogenesis in mTORopathies. Front Neuroanat 2021; 15:664695. [PMID: 33897381 PMCID: PMC8064518 DOI: 10.3389/fnana.2021.664695] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Accepted: 03/17/2021] [Indexed: 12/30/2022] Open
Abstract
Hyperactivation of the mechanistic target of rapamycin complex 1 (mTORC1) due to mutations in genes along the PI3K-mTOR pathway and the GATOR1 complex causes a spectrum of neurodevelopmental disorders (termed mTORopathies) associated with malformation of cortical development and intractable epilepsy. Despite these gene variants’ converging impact on mTORC1 activity, emerging findings suggest that these variants contribute to epilepsy through both mTORC1-dependent and -independent mechanisms. Here, we review the literature on in utero electroporation-based animal models of mTORopathies, which recapitulate the brain mosaic pattern of mTORC1 hyperactivity, and compare the effects of distinct PI3K-mTOR pathway and GATOR1 complex gene variants on cortical development and epilepsy. We report the outcomes on cortical pyramidal neuronal placement, morphology, and electrophysiological phenotypes, and discuss some of the converging and diverging mechanisms responsible for these alterations and their contribution to epileptogenesis. We also discuss potential therapeutic strategies for epilepsy, beyond mTORC1 inhibition with rapamycin or everolimus, that could offer personalized medicine based on the gene variant.
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Affiliation(s)
- Lena H Nguyen
- Department of Neurosurgery, Yale School of Medicine, Yale University, New Haven, CT, United States.,Department of Cellular & Molecular Physiology, Yale School of Medicine, Yale University, New Haven, CT, United States
| | - Angélique Bordey
- Department of Neurosurgery, Yale School of Medicine, Yale University, New Haven, CT, United States.,Department of Cellular & Molecular Physiology, Yale School of Medicine, Yale University, New Haven, CT, United States
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Hsieh LS, Wen JH, Nguyen LH, Zhang L, Getz S, Torres-Reveron J, Wang Y, Spencer DD, Bordey A. Ectopic HCN4 expression drives mTOR-dependent epilepsy in mice. Sci Transl Med 2020; 12:12/570/eabc1492. [PMID: 33208499 PMCID: PMC9888000 DOI: 10.1126/scitranslmed.abc1492] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Accepted: 07/31/2020] [Indexed: 02/03/2023]
Abstract
The causative link between focal cortical malformations (FCMs) and epilepsy is well accepted, especially among patients with focal cortical dysplasia type II (FCDII) and tuberous sclerosis complex (TSC). However, the mechanisms underlying seizures remain unclear. Using a mouse model of TSC- and FCDII-associated FCM, we showed that FCM neurons were responsible for seizure activity via their unexpected abnormal expression of the hyperpolarization-activated cyclic nucleotide-gated potassium channel isoform 4 (HCN4), which is normally not present in cortical pyramidal neurons after birth. Increasing intracellular cAMP concentrations, which preferentially affects HCN4 gating relative to the other isoforms, drove repetitive firing of FCM neurons but not control pyramidal neurons. Ectopic HCN4 expression was dependent on the mechanistic target of rapamycin (mTOR), preceded the onset of seizures, and was also found in diseased neurons in tissue resected from patients with TSC and FCDII. Last, blocking HCN4 channel activity in FCM neurons prevented epilepsy in the mouse model. These findings suggest that HCN4 play a main role in seizure and identify a cAMP-dependent seizure mechanism in TSC and FCDII. Furthermore, the unique expression of HCN4 exclusively in FCM neurons suggests that gene therapy targeting HCN4 might be effective in reducing seizures in FCDII or TSC.
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Affiliation(s)
- Lawrence S. Hsieh
- Department of Neurosurgery, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA
| | - John H. Wen
- Department of Neurosurgery, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA
| | - Lena H. Nguyen
- Department of Neurosurgery, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA
| | - Longbo Zhang
- Department of Neurosurgery, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA
| | - Stephanie Getz
- Department of Neurosurgery, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA
| | - Juan Torres-Reveron
- Department of Neurosurgery, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA
| | - Ying Wang
- Emergency Department, Xiangya Hospital, Central South University, 87 Xiangya Street, Changsha, Hunan 410008, China
| | - Dennis D. Spencer
- Department of Neurosurgery, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA
| | - Angélique Bordey
- Department of Neurosurgery, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA,Department of Cellular & Molecular Physiology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA,To whom correspondence should be addressed: Angélique Bordey, Ph.D., Department of Neurosurgery, Yale University School of Medicine, 333 Cedar Street, FMB 422, New Haven, CT 06520-8082, Phone: 203-737-2515, Fax: 203-737-2159,
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10
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Alsaqati M, Heine VM, Harwood AJ. Pharmacological intervention to restore connectivity deficits of neuronal networks derived from ASD patient iPSC with a TSC2 mutation. Mol Autism 2020; 11:80. [PMID: 33076974 PMCID: PMC7574213 DOI: 10.1186/s13229-020-00391-w] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Accepted: 10/08/2020] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Tuberous sclerosis complex (TSC) is a rare genetic multisystemic disorder resulting from autosomal dominant mutations in the TSC1 or TSC2 genes. It is characterised by hyperactivation of the mechanistic target of rapamycin complex 1 (mTORC1) pathway and has severe neurodevelopmental and neurological components including autism, intellectual disability and epilepsy. In human and rodent models, loss of the TSC proteins causes neuronal hyperexcitability and synaptic dysfunction, although the consequences of these changes for the developing central nervous system are currently unclear. METHODS Here we apply multi-electrode array-based assays to study the effects of TSC2 loss on neuronal network activity using autism spectrum disorder (ASD) patient-derived iPSCs. We examine both temporal synchronisation of neuronal bursting and spatial connectivity between electrodes across the network. RESULTS We find that ASD patient-derived neurons with a functional loss of TSC2, in addition to possessing neuronal hyperactivity, develop a dysfunctional neuronal network with reduced synchronisation of neuronal bursting and lower spatial connectivity. These deficits of network function are associated with elevated expression of genes for inhibitory GABA signalling and glutamate signalling, indicating a potential abnormality of synaptic inhibitory-excitatory signalling. mTORC1 activity functions within a homeostatic triad of protein kinases, mTOR, AMP-dependent protein Kinase 1 (AMPK) and Unc-51 like Autophagy Activating Kinase 1 (ULK1) that orchestrate the interplay of anabolic cell growth and catabolic autophagy while balancing energy and nutrient homeostasis. The mTOR inhibitor rapamycin suppresses neuronal hyperactivity, but does not increase synchronised network activity, whereas activation of AMPK restores some aspects of network activity. In contrast, the ULK1 activator, LYN-1604, increases the network behaviour, shortens the network burst lengths and reduces the number of uncorrelated spikes. LIMITATIONS Although a robust and consistent phenotype is observed across multiple independent iPSC cultures, the results are based on one patient. There may be more subtle differences between patients with different TSC2 mutations or differences of polygenic background within their genomes. This may affect the severity of the network deficit or the pharmacological response between TSC2 patients. CONCLUSIONS Our observations suggest that there is a reduction in the network connectivity of the in vitro neuronal network associated with ASD patients with TSC2 mutation, which may arise via an excitatory/inhibitory imbalance due to increased GABA-signalling at inhibitory synapses. This abnormality can be effectively suppressed via activation of ULK1.
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Affiliation(s)
- Mouhamed Alsaqati
- Neuroscience and Mental Health Research Institute, Hadyn Ellis Building, Cathays, Cardiff, CF24 4HQ, UK
- Division of Psychological Medicine and Clinical Neurosciences (DPMCN), School of Medicine, Cardiff University, Cardiff, UK
| | - Vivi M Heine
- Department of Complex Trait Genetics, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
- Child and Youth Psychiatry, Emma Children's Hospital, Amsterdam UMC, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Adrian J Harwood
- Neuroscience and Mental Health Research Institute, Hadyn Ellis Building, Cathays, Cardiff, CF24 4HQ, UK.
- School of Bioscience, The Sir Martin Evans Building, Museum Ave, Cardiff, CF10 3AX, UK.
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11
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Takai A, Yamaguchi M, Yoshida H, Chiyonobu T. Investigating Developmental and Epileptic Encephalopathy Using Drosophila melanogaster. Int J Mol Sci 2020; 21:ijms21176442. [PMID: 32899411 PMCID: PMC7503973 DOI: 10.3390/ijms21176442] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2020] [Revised: 08/30/2020] [Accepted: 09/01/2020] [Indexed: 12/16/2022] Open
Abstract
Developmental and epileptic encephalopathies (DEEs) are the spectrum of severe epilepsies characterized by early-onset, refractory seizures occurring in the context of developmental regression or plateauing. Early infantile epileptic encephalopathy (EIEE) is one of the earliest forms of DEE, manifesting as frequent epileptic spasms and characteristic electroencephalogram findings in early infancy. In recent years, next-generation sequencing approaches have identified a number of monogenic determinants underlying DEE. In the case of EIEE, 85 genes have been registered in Online Mendelian Inheritance in Man as causative genes. Model organisms are indispensable tools for understanding the in vivo roles of the newly identified causative genes. In this review, we first present an overview of epilepsy and its genetic etiology, especially focusing on EIEE and then briefly summarize epilepsy research using animal and patient-derived induced pluripotent stem cell (iPSC) models. The Drosophila model, which is characterized by easy gene manipulation, a short generation time, low cost and fewer ethical restrictions when designing experiments, is optimal for understanding the genetics of DEE. We therefore highlight studies with Drosophila models for EIEE and discuss the future development of their practical use.
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Affiliation(s)
- Akari Takai
- Department of Pediatrics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan;
| | - Masamitsu Yamaguchi
- Department of Applied Biology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 603-8585, Japan; (M.Y.); (H.Y.)
- Kansai Gakken Laboratory, Kankyo Eisei Yakuhin Co. Ltd., Kyoto 619-0237, Japan
| | - Hideki Yoshida
- Department of Applied Biology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 603-8585, Japan; (M.Y.); (H.Y.)
| | - Tomohiro Chiyonobu
- Department of Pediatrics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan;
- Correspondence:
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12
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Samanta D. An Updated Review of Tuberous Sclerosis Complex-Associated Autism Spectrum Disorder. Pediatr Neurol 2020; 109:4-11. [PMID: 32563542 DOI: 10.1016/j.pediatrneurol.2020.03.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Revised: 03/01/2020] [Accepted: 03/03/2020] [Indexed: 01/30/2023]
Abstract
Tuberous sclerosis complex (TSC) is a neurocutaneous disorder caused by mutations of either the TSC1 or TSC2 gene. Various neuropsychiatric features, including autism, are prevalent in TSC. Recently, significant progress has been possible with the prospective calculation of the prevalence of autism in TSC, identification of early clinical and neurophysiological biomarkers to predict autism, and investigation of different therapies to prevent autism in this high-risk population. The author provides a narrative review of recent findings related to biomarkers for diagnosis of autism in TSC, as well as recent studies related to the management of TSC-associated autism. Further sophisticated modeling and analysis are required to understand the role of different models-tuber models, seizures and related neurophysiological factors models, genotype models, and brain connectivity models-to unravel the neurobiological basis of autism in TSC. Early neuropsychologic assessments may be beneficial in this high-risk group. Targeted intervention to improve visual skill, cognition, and fine motor skills with later addition of social skill training can be helpful. Multicenter, prospective studies are ongoing to identify if presymptomatic treatment with vigabatrin in patients with TSC can improve outcomes, including autism. Several studies indicated reasonable safety of everolimus in young children, and its potential application in high-risk infants with TSC, before the closure of the temporal window of permanent changes, maybe undertaken shortly.
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Affiliation(s)
- Debopam Samanta
- Child Neurology Section, Department of Pediatrics, University of Arkansas for Medical Sciences, Little Rock, Arkansas.
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13
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Liu S, Yu T, Guan Y, Zhang K, Ding P, Chen L, Shan Y, Guo Q, Liu Q, Yao Y, Yang M, Zhang S, Lin Y, Zhao R, Mao Z, Zhang J, Zhang C, Zhang R, Yang Z, Qian R, Li Y, Zhang G, Yuan L, Yang W, Tian H, Zhang H, Li W, Zhang X, Yin J, Guo Y, Zou L, Qin J, Fang F, Wang X, Ge M, Liang S. Resective epilepsy surgery in tuberous sclerosis complex: a nationwide multicentre retrospective study from China. Brain 2020; 143:570-581. [PMID: 31953931 DOI: 10.1093/brain/awz411] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Revised: 11/11/2019] [Accepted: 11/14/2019] [Indexed: 11/13/2022] Open
Abstract
At least 50% of patients with tuberous sclerosis complex present with intractable epilepsy; for these patients, resective surgery is a treatment option. Here, we report a nationwide multicentre retrospective study and analyse the long-term seizure and neuropsychological outcomes of epilepsy surgery in patients with tuberous sclerosis complex. There were 364 patients who underwent epilepsy surgery in the study. Patients' clinical data, postoperative seizure outcomes at 1-, 4-, and 10-year follow-ups, preoperative and postoperative intelligence quotients, and quality of life at 1-year follow-up were collected. The patients' ages at surgery were 10.35 ± 7.70 years (range: 0.5-47). The percentage of postoperative seizure freedom was 71% (258/364) at 1-year, 60% (118/196) at 4-year, and 51% (36/71) at 10-year follow-up. Influence factors of postoperative seizure freedom were the total removal of epileptogenic tubers and the presence of outstanding tuber on MRI at 1- and 4-year follow-ups. Furthermore, monthly seizure (versus daily seizure) was also a positive influence factor for postoperative seizure freedom at 1-year follow-up. The presence of an outstanding tuber on MRI was the only factor influencing seizure freedom at 10-year follow-up. Postoperative quality of life and intelligence quotient improvements were found in 43% (112/262) and 28% (67/242) of patients, respectively. Influence factors of postoperative quality of life and intelligence quotient improvement were postoperative seizure freedom and preoperative low intelligence quotient. The percentage of seizure freedom in the tuberectomy group was significantly lower compared to the tuberectomy plus and lobectomy groups at 1- and 4-year follow-ups. In conclusion, this study, the largest nationwide multi-centre study on resective epilepsy surgery, resulted in improved seizure outcomes and quality of life and intelligence quotient improvements in patients with tuberous sclerosis complex. Seizure freedom was often achieved in patients with an outstanding tuber on MRI, total removal of epileptogenic tubers, and tuberectomy plus. Quality of life and intelligence quotient improvements were frequently observed in patients with postoperative seizure freedom and preoperative low intelligence quotient.
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Affiliation(s)
- Shiyong Liu
- Department of Neurosurgery, Xinqiao Hospital, Army Military Medical University, Chongqing, China
| | - Tao Yu
- Department of Functional Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Yuguang Guan
- Department of Neurosurgery, Sanbo Brain Hospital, Capital Medical University, Beijing, China
| | - Kai Zhang
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Ping Ding
- Department of Neurosurgery, Fourth Medical Center of PLA General Hospital, Beijing, China
| | - Lei Chen
- Department of Neurology, Western China Hospital, Sichuan University, Chengdu, China
| | - Yongzhi Shan
- Department of Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Qiang Guo
- Department of Neurosurgery, Guangdong Sanjiu Brain Hospital, Guangzhou, China
| | - Qingzhu Liu
- Pediatric Epilepsy Surgery Center, First Affiliated Hospital of Peking University, Beijing, China
| | - Yi Yao
- Department of Neurosurgery, Xiamen Hongai Hospital, Xiamen, China
| | - Meihua Yang
- Department of Neurosurgery, Xinqiao Hospital, Army Military Medical University, Chongqing, China
| | - Shaohui Zhang
- Department of Neurosurgery, Fourth Medical Center of PLA General Hospital, Beijing, China
| | - Yuanxiang Lin
- Department of Neurosurgery, First Affiliated Hospital, Fujian Medical University, Fuzhou, China
| | - Rui Zhao
- Department of Neurosurgery, Children Hospital, Fudan University, Shanghai, China
| | - Zhiqi Mao
- Department of Neurosurgery, First Medical Center of PLA General Hospital, Beijing, China
| | - Juncheng Zhang
- Department of Neurosurgery, Affiliated Hospital of Jining Medical College, Jining, China
| | - Chunqing Zhang
- Department of Neurosurgery, Xinqiao Hospital, Army Military Medical University, Chongqing, China
| | - Rui Zhang
- Department of Functional Neurosurgery, Brain Hospital, Nanjing Medical University, Nanjing, China
| | - Zhiquan Yang
- Department of Neurosurgery, Xiangya Hospital, Central Southern University, Changsha, China
| | - Ruobing Qian
- Department of Neurosurgery, First Affiliated Hospital, University of Science and Technology of China, Hefei, China
| | - Yunlin Li
- Department of Neurosurgery, Children Hospital, Capital Institute of Pediatrics, Beijing, China
| | - Guangming Zhang
- Department of Neurosurgery, Beijing Aviation General Hospital, Beijing, China
| | - Liu Yuan
- Department of Neurosurgery, Fourth Medical Center of PLA General Hospital, Beijing, China
| | - Weidong Yang
- Department of Neurosurgery, General Hospital, Tianjin Medical University, Tianjin, China
| | - Hong Tian
- Department of Neurosurgery, China-Japan Friendship Hospital, Beijing, China
| | - Hua Zhang
- Department of Neurosurgery, First Affiliated Hospital, Xi'an Jiaotong University, Xi'an, China
| | - Wenling Li
- Department of Neurosurgery, Second Affiliated Hospital, Hebei Medical University, Shijiazhuang, China
| | - Xinwei Zhang
- Department of Neurosurgery, Third Affiliated Hospital, Southern Medical University, Guangzhou, China
| | - Jian Yin
- Department of Neurosurgery, Second Affiliated Hospital, Dalian Medical University, Dalian, China
| | - Yanwu Guo
- Department of Neurosurgery, Zhujiang Hospital, Southern Medical University, Guangzhou, China
| | - Liping Zou
- Pediatrics Department, First Medical Center of PLA General Hospital, Beijing, China
| | - Jiong Qin
- Pediatrics Department, Beijing People's Hospital, Peking University, Beijing, China
| | - Fang Fang
- Neurology Department, Beijing Children's Hospital, Capital Medical University, Beijing, China
| | - Xu Wang
- Neurology Department, Beijing Children's Hospital, Capital Medical University, Beijing, China
| | - Ming Ge
- Neurosurgery Department, Beijing Children's Hospital, Capital Medical University, Beijing, China
| | - Shuli Liang
- Functional Neurosurgery Department, Beijing Children's Hospital, Capital Medical University, Beijing, China
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14
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Velíšek L, Velíšková J. Modeling epileptic spasms during infancy: Are we heading for the treatment yet? Pharmacol Ther 2020; 212:107578. [PMID: 32417271 DOI: 10.1016/j.pharmthera.2020.107578] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Accepted: 05/07/2020] [Indexed: 12/22/2022]
Abstract
Infantile spasms (IS or epileptic spasms during infancy) were first described by Dr. William James West (aka West syndrome) in his own son in 1841. While rare by definition (occurring in 1 per 3200-3400 live births), IS represent a major social and treatment burden. The etiology of IS varies - there are many (>200) different known pathologies resulting in IS and still in about one third of cases there is no obvious reason. With the advancement of genetic analysis, role of certain genes (such as ARX or CDKL5 and others) in IS appears to be important. Current treatment strategies with incomplete efficacy and serious potential adverse effects include adrenocorticotropin (ACTH), corticosteroids (prednisone, prednisolone) and vigabatrin, more recently also a combination of hormones and vigabatrin. Second line treatments include pyridoxine (vitamin B6) and ketogenic diet. Additional treatment approaches use rapamycin, cannabidiol, valproic acid and other anti-seizure medications. Efficacy of these second line medications is variable but usually inferior to hormonal treatments and vigabatrin. Thus, new and effective models of this devastating condition are required for the search of additional treatment options as well as for better understanding the mechanisms of IS. Currently, eight models of IS are reviewed along with the ideas and mechanisms behind these models, drugs tested using the models and their efficacy and usefulness. Etiological variety of IS is somewhat reflected in the variety of the models. However, it seems that for finding precise personalized approaches, this variety is necessary as there is no "one-size-fits-all" approach possible for both IS in particular and epilepsy in general.
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Affiliation(s)
- Libor Velíšek
- Departments of Cell Biology & Anatomy, New York Medical College, Valhalla, NY, USA; Departments of Pediatrics, New York Medical College, Valhalla, NY, USA; Departments of Neurology, New York Medical College, Valhalla, NY, USA.
| | - Jana Velíšková
- Departments of Cell Biology & Anatomy, New York Medical College, Valhalla, NY, USA; Departments of Neurology, New York Medical College, Valhalla, NY, USA; Departments of Obstetrics & Gynecology, New York Medical College, Valhalla, NY, USA
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15
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Goz RU, Akgül G, LoTurco JJ. BRAFV600E expression in neural progenitors results in a hyperexcitable phenotype in neocortical pyramidal neurons. J Neurophysiol 2020; 123:2449-2464. [PMID: 32401131 DOI: 10.1152/jn.00523.2019] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Somatic mutations have emerged as the likely cause of focal epilepsies associated with developmental malformations and epilepsy-associated glioneuronal tumors (GNT). Somatic BRAFV600E mutations in particular have been detected in the majority of low-grade neuroepithelial tumors (LNETS) and in neurons in focal cortical dysplasias adjacent to epilepsy-associated tumors. Furthermore, conditional expression of an activating BRAF mutation in neocortex causes seizures in mice. In this study we characterized the cellular electrophysiology of layer 2/3 neocortical pyramidal neurons induced to express BRAFV600E from neural progenitor stages. In utero electroporation of a piggyBac transposase plasmid system was used to introduce transgenes expressing BRAF wild type (BRAFwt), BRAFV600E, and/or enhanced green fluorescent protein (eGFP) and monomeric red fluorescent protein (mRFP) into radial glia progenitors in mouse embryonic cortex. Whole cell patch-clamp recordings of pyramidal neurons in slices prepared from both juvenile and adult mice showed that BRAFV600E resulted in neurons with a distinct hyperexcitable phenotype characterized by depolarized resting membrane potentials, increased input resistances, lowered action potential (AP) thresholds, and increased AP firing frequencies. Some of the BRAFV600E-expressing neurons normally destined for upper cortical layers by their birthdate were stalled in their migration and occupied lower cortical layers. BRAFV600E-expressing neurons also displayed increased hyperpolarization-induced inward currents (Ih) and decreased sustained potassium currents. Neurons adjacent to BRAFV600E transgene-expressing neurons, and neurons with TSC1 genetically deleted by CRISPR or those induced to carry PIK3CAE545K transgenes, did not show an excitability phenotype similar to that of BRAFV600E-expressing neurons. Together, these results indicate that BRAFV600E leads to a distinct hyperexcitable neuronal phenotype.NEW & NOTEWORTHY This study is the first to report the cell autonomous effects of BRAFV600E mutations on the intrinsic neuronal excitability. We show that BRAFV600E alters multiple electrophysiological parameters in neocortical neurons. Similar excitability changes did not occur in cells neighboring BRAFV600E-expressing neurons, after overexpression of wild-type BRAF transgenes, or after introduction of mutations affecting the mammalian target of rapamycin (mTOR) or the catalytic subunit of phosphoinositide 3-kinase (PIK3CA). We conclude that BRAFV600E causes a distinct, cell autonomous, highly excitable neuronal phenotype when introduced somatically into neocortical neuronal progenitors.
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Affiliation(s)
- Roman U Goz
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut.,Department of Psychology, University of Connecticut, Storrs, Connecticut
| | - Gülcan Akgül
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut
| | - Joseph J LoTurco
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut
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16
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Abstract
Epilepsy is a long-term neurological disease characterized by convulsions that can be recurrent. It is mainly caused by an imbalance between excitation and inhibition in the central nervous system. Currently, the pathogenesis is still unclear, although it may be related to changes in ion channels, neurotransmitters and glial cells. In recent years, increasing attention has been paid to the role of autophagy in the development of epilepsy. This chapter focuses on the role of the mTOR pathway in epileptogenesis and the relationship between autophagy, glycogen metabolism and Lafora disease and discusses the potential role of autophagy as a target for the treatment of epilepsy.
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Affiliation(s)
- Meihong Lv
- Institute of Neuroscience, Soochow University, Suzhou, Jiangsu Province, China
| | - Quanhong Ma
- Institute of Neuroscience, Soochow University, Suzhou, Jiangsu Province, China.
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17
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Lv M, Ma Q. Autophagy in Neurodevelopmental Disorders. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1207:171-182. [PMID: 32671746 DOI: 10.1007/978-981-15-4272-5_11] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Neurodevelopmental diseases are a class of neurodevelopmental disorders characterized by cognitive impairment and behavioral abnormalities and are mainly manifested as developmental disorders of the brain and nervous system. The pathological mechanism is not fully understood and may be related to hereditary or environmental factors. The elevation of autophagy during neural development suggests that autophagy may be involved in the process of neurodevelopment. This chapter focuses on the important functions of autophagy in all aspects of neurodevelopment and the role and mechanism of autophagy in neurodevelopmental disorders, especially in autism spectrum disorder.
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Affiliation(s)
- Meihong Lv
- Institute of Neuroscience, Soochow University, Suzhou, Jiangsu Province, China
| | - Quanhong Ma
- Institute of Neuroscience, Soochow University, Suzhou, Jiangsu Province, China.
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18
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Neal A, Ostrowsky-Coste K, Jung J, Lagarde S, Maillard L, Kahane P, Touraine R, Catenoix H, Montavont A, Isnard J, Arzimanoglou A, Bartolomei F, Guenot M, Rheims S. Epileptogenicity in tuberous sclerosis complex: A stereoelectroencephalographic study. Epilepsia 2019; 61:81-95. [PMID: 31860139 DOI: 10.1111/epi.16410] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Revised: 11/19/2019] [Accepted: 11/19/2019] [Indexed: 12/13/2022]
Abstract
OBJECTIVE In tuberous sclerosis complex (TSC)-associated drug-resistant epilepsy, the optimal invasive electroencephalographic (EEG) and operative approach remains unclear. We examined the role of stereo-EEG in TSC and used stereo-EEG data to investigate tuber and surrounding cortex epileptogenicity. METHODS We analyzed 18 patients with TSC who underwent stereo-EEG (seven adults). One hundred ten seizures were analyzed with the epileptogenicity index (EI). In 13 patients with adequate tuber sampling, five anatomical regions of interest (ROIs) were defined: dominant tuber (tuber with highest median EI), perituber cortex, secondary tuber (tuber with second highest median EI), nearby cortex (normal-appearing cortex in the same lobe as dominant tuber), and distant cortex (in other lobes). At the seizure level, epileptogenicity of ROIs was examined by comparing the highest EI recorded within each anatomical region. At the patient level, epileptogenic zone (EZ) organization was separated into focal tuber (EZ confined to dominant tuber) and complex (all other patterns). RESULTS The most epileptogenic ROI was the dominant tuber, with higher EI than perituber cortex, secondary tuber, nearby cortex, and distant cortex (P < .001). A focal tuber EZ organization was identified in seven patients. This group had 80% Engel IA postsurgical outcome and distinct dominant tuber characteristics: continuous interictal discharges (IEDs; 100%), fluid-attenuated inversion recovery (FLAIR) hypointense center (86%), center-to-rim EI gradient, and stimulation-induced seizures (71%). In contrast, six patients had a complex EZ organization, characterized by nearby cortex as the most epileptogenic region and 40% Engel IA outcome. At the intratuber level, the combination of FLAIR hypointense center, continuous IEDs, and stimulation-induced seizures offered 98% specificity for a focal tuber EZ organization. SIGNIFICANCE Tubers with focal EZ organization have a striking similarity to type II focal cortical dysplasia. The presence of distinct EZ organizations has significant implications for EZ hypothesis generation, invasive EEG approach, and resection strategy.
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Affiliation(s)
- Andrew Neal
- National Institute of Health and Medical Research U1028/National Center for Scientific Research, Mixed Unit of Research 5292, Lyon Neuroscience Research Center, Lyon, France.,Department of Functional Neurology and Epileptology, Member of the ERN EpiCARE Lyon University Hospital and Lyon 1 University, Lyon, France.,Department of Neuroscience, Faculty of Medicine, Nursing, and Health Sciences, Central Clinical School, Monash University, Melbourne, Victoria, Australia
| | - Karine Ostrowsky-Coste
- Department of Functional Neurology and Epileptology, Member of the ERN EpiCARE Lyon University Hospital and Lyon 1 University, Lyon, France.,Department of Pediatric Clinical Epileptology, Sleep Disorders, and Functional Neurology, Member of the ERN EpiCARE Lyon University Hospital, Lyon, France
| | - Julien Jung
- National Institute of Health and Medical Research U1028/National Center for Scientific Research, Mixed Unit of Research 5292, Lyon Neuroscience Research Center, Lyon, France.,Department of Functional Neurology and Epileptology, Member of the ERN EpiCARE Lyon University Hospital and Lyon 1 University, Lyon, France
| | - Stanislas Lagarde
- Epileptology Department, Public Assistance Hospitals of Marseille, National Institute of Health and Medical Research, Institute of Systems Neuroscience, Timone Hospital, Aix Marseille University, Marseille, France
| | - Louis Maillard
- Neurology Department, University Hospital of Nancy, Nancy, France
| | - Philippe Kahane
- Department of Neurology, Grenoble-Alpes University Hospital, Grenoble Institute of Neurosciences, National Institute of Health and Medical Research U1216, Grenoble Alpes University, Grenoble, France
| | - Renaud Touraine
- Department of Genetics, University Hospital Center-North Hospital, Saint Etienne, France
| | - Helene Catenoix
- National Institute of Health and Medical Research U1028/National Center for Scientific Research, Mixed Unit of Research 5292, Lyon Neuroscience Research Center, Lyon, France.,Department of Functional Neurology and Epileptology, Member of the ERN EpiCARE Lyon University Hospital and Lyon 1 University, Lyon, France
| | - Alexandra Montavont
- National Institute of Health and Medical Research U1028/National Center for Scientific Research, Mixed Unit of Research 5292, Lyon Neuroscience Research Center, Lyon, France.,Department of Functional Neurology and Epileptology, Member of the ERN EpiCARE Lyon University Hospital and Lyon 1 University, Lyon, France
| | - Jean Isnard
- National Institute of Health and Medical Research U1028/National Center for Scientific Research, Mixed Unit of Research 5292, Lyon Neuroscience Research Center, Lyon, France.,Department of Functional Neurology and Epileptology, Member of the ERN EpiCARE Lyon University Hospital and Lyon 1 University, Lyon, France
| | - Alexis Arzimanoglou
- National Institute of Health and Medical Research U1028/National Center for Scientific Research, Mixed Unit of Research 5292, Lyon Neuroscience Research Center, Lyon, France.,Department of Pediatric Clinical Epileptology, Sleep Disorders, and Functional Neurology, Member of the ERN EpiCARE Lyon University Hospital, Lyon, France
| | - Fabrice Bartolomei
- Epileptology Department, Public Assistance Hospitals of Marseille, National Institute of Health and Medical Research, Institute of Systems Neuroscience, Timone Hospital, Aix Marseille University, Marseille, France
| | - Marc Guenot
- National Institute of Health and Medical Research U1028/National Center for Scientific Research, Mixed Unit of Research 5292, Lyon Neuroscience Research Center, Lyon, France.,Department of Functional Neurosurgery, Member of the ERN EpiCARE Lyon University Hospital and Lyon 1 University, Lyon, France
| | - Sylvain Rheims
- National Institute of Health and Medical Research U1028/National Center for Scientific Research, Mixed Unit of Research 5292, Lyon Neuroscience Research Center, Lyon, France.,Department of Functional Neurology and Epileptology, Member of the ERN EpiCARE Lyon University Hospital and Lyon 1 University, Lyon, France.,Idée Epilepsy Institute, Lyon, France
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19
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Mühlebner A, Bongaarts A, Sarnat HB, Scholl T, Aronica E. New insights into a spectrum of developmental malformations related to mTOR dysregulations: challenges and perspectives. J Anat 2019; 235:521-542. [PMID: 30901081 DOI: 10.1111/joa.12956] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/15/2019] [Indexed: 12/20/2022] Open
Abstract
In recent years the role of the mammalian target of rapamycin (mTOR) pathway has emerged as crucial for normal cortical development. Therefore, it is not surprising that aberrant activation of mTOR is associated with developmental malformations and epileptogenesis. A broad spectrum of malformations of cortical development, such as focal cortical dysplasia (FCD) and tuberous sclerosis complex (TSC), have been linked to either germline or somatic mutations in mTOR pathway-related genes, commonly summarised under the umbrella term 'mTORopathies'. However, there are still a number of unanswered questions regarding the involvement of mTOR in the pathophysiology of these abnormalities. Therefore, a monogenetic disease, such as TSC, can be more easily applied as a model to study the mechanisms of epileptogenesis and identify potential new targets of therapy. Developmental neuropathology and genetics demonstrate that FCD IIb and hemimegalencephaly are the same diseases. Constitutive activation of mTOR signalling represents a shared pathogenic mechanism in a group of developmental malformations that have histopathological and clinical features in common, such as epilepsy, autism and other comorbidities. We seek to understand the effect of mTOR dysregulation in a developing cortex with the propensity to generate seizures as well as the aftermath of the surrounding environment, including the white matter.
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Affiliation(s)
- A Mühlebner
- Department of Neuropathology, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
| | - A Bongaarts
- Department of Neuropathology, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
| | - H B Sarnat
- Departments of Paediatrics, Pathology (Neuropathology) and Clinical Neurosciences, University of Calgary Cumming School of Medicine and Alberta Children's Hospital Research Institute (Owerko Centre), Calgary, AB, Canada
| | - T Scholl
- Department of Paediatric and Adolescent Medicine, Medical University of Vienna, Vienna, Austria
| | - E Aronica
- Department of Neuropathology, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands.,Stichting Epilepsie Instellingen Nederland (SEIN), Amsterdam, The Netherlands
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20
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Nadadhur AG, Alsaqati M, Gasparotto L, Cornelissen-Steijger P, van Hugte E, Dooves S, Harwood AJ, Heine VM. Neuron-Glia Interactions Increase Neuronal Phenotypes in Tuberous Sclerosis Complex Patient iPSC-Derived Models. Stem Cell Reports 2018; 12:42-56. [PMID: 30581017 PMCID: PMC6335594 DOI: 10.1016/j.stemcr.2018.11.019] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Revised: 11/21/2018] [Accepted: 11/22/2018] [Indexed: 12/20/2022] Open
Abstract
Tuberous sclerosis complex (TSC) is a rare neurodevelopmental disorder resulting from autosomal dominant mutations in the TSC1 or TSC2 genes, leading to a hyperactivated mammalian target of rapamycin (mTOR) pathway, and gray and white matter defects in the brain. To study the involvement of neuron-glia interactions in TSC phenotypes, we generated TSC patient induced pluripotent stem cell (iPSC)-derived cortical neuronal and oligodendrocyte (OL) cultures. TSC neuron mono-cultures showed increased network activity, as measured by calcium transients and action potential firing, and increased dendritic branching. However, in co-cultures with OLs, neuronal defects became more apparent, showing cellular hypertrophy and increased axonal density. In addition, TSC neuron-OL co-cultures showed increased OL cell proliferation and decreased OL maturation. Pharmacological intervention with the mTOR regulator rapamycin suppressed these defects. Our patient iPSC-based model, therefore, shows a complex cellular TSC phenotype arising from the interaction of neuronal and glial cells and provides a platform for TSC disease modeling and drug development. TSC neuron mono-cultures show an increase in network activity and dendritic branching TSC co-cultures show hypertrophy and an increase in axonal length and OL proliferation mTOR regulators normalize TSC neuronal and glial phenotypes
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Affiliation(s)
- Aishwarya G Nadadhur
- Department of Functional Genomics, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, Amsterdam 1081 HV, the Netherlands
| | - Mouhamed Alsaqati
- Neuroscience and Mental Health Research Institute, Cardiff University, Hadyn Ellis Building, Maindy Road, Cardiff CF24 4HQ, UK
| | - Lisa Gasparotto
- Pediatric Neurology, Emma Children's Hospital, Amsterdam UMC, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, Amsterdam 1081 HV, the Netherlands
| | - Paulien Cornelissen-Steijger
- Pediatric Neurology, Emma Children's Hospital, Amsterdam UMC, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, Amsterdam 1081 HV, the Netherlands
| | - Eline van Hugte
- Department of Functional Genomics, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, Amsterdam 1081 HV, the Netherlands
| | - Stephanie Dooves
- Pediatric Neurology, Emma Children's Hospital, Amsterdam UMC, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, Amsterdam 1081 HV, the Netherlands
| | - Adrian J Harwood
- Neuroscience and Mental Health Research Institute, Cardiff University, Hadyn Ellis Building, Maindy Road, Cardiff CF24 4HQ, UK
| | - Vivi M Heine
- Pediatric Neurology, Emma Children's Hospital, Amsterdam UMC, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, Amsterdam 1081 HV, the Netherlands; Department of Complex Trait Genetics, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, Amsterdam 1081 HV, the Netherlands.
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21
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Cepeda C, Levinson S, Yazon VW, Barry J, Mathern GW, Fallah A, Vinters HV, Levine MS, Wu JY. Cellular antiseizure mechanisms of everolimus in pediatric tuberous sclerosis complex, cortical dysplasia, and non-mTOR-mediated etiologies. Epilepsia Open 2018; 3:180-190. [PMID: 30564777 PMCID: PMC6293070 DOI: 10.1002/epi4.12253] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/28/2018] [Indexed: 11/25/2022] Open
Abstract
The present study was designed to examine the potential cellular antiseizure mechanisms of everolimus, a mechanistic target of rapamycin (mTOR) pathway blocker, in pediatric epilepsy cases. Cortical tissue samples obtained from pediatric patients (n = 11, ages 0.67–6.75 years) undergoing surgical resections for the treatment of their pharmacoresistant epilepsy were examined electrophysiologically in ex vivo slices. The cohort included mTOR‐mediated pathologies (tuberous sclerosis complex [TSC] and severe cortical dysplasia [CD]) as well as non–mTOR‐mediated pathologies (tumor and perinatal infarct). Bath application of everolimus (2 μm) had practically no effect on spontaneous inhibitory postsynaptic activity. In contrast, long‐term application of everolimus reduced spontaneous excitatory postsynaptic activity, burst discharges induced by blockade of γ‐aminobutyric acid A (GABAA) receptors, and epileptiform activity generated by 4‐aminopyridine, a K+ channel blocker. The antiseizure effects were more pronounced in TSC and CD cases, whereas in non–mTOR‐mediated pathologies, the effects were subtle at best. These results support further clinical trials of everolimus in mTOR pathway–mediated pathologies and emphasize that the effects require sustained exposure over time.
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Affiliation(s)
- Carlos Cepeda
- IDDRC Semel Institute for Neuroscience and Human Behavior UCLA School of Medicine University of California Los Angeles Los Angeles California, U.S.A
| | - Simon Levinson
- IDDRC Semel Institute for Neuroscience and Human Behavior UCLA School of Medicine University of California Los Angeles Los Angeles California, U.S.A
| | - Vannah-Wila Yazon
- IDDRC Semel Institute for Neuroscience and Human Behavior UCLA School of Medicine University of California Los Angeles Los Angeles California, U.S.A
| | - Joshua Barry
- IDDRC Semel Institute for Neuroscience and Human Behavior UCLA School of Medicine University of California Los Angeles Los Angeles California, U.S.A
| | - Gary W Mathern
- IDDRC Semel Institute for Neuroscience and Human Behavior UCLA School of Medicine University of California Los Angeles Los Angeles California, U.S.A.,Department of Neurosurgery David Geffen School of Medicine at University of California Los Angeles Los Angeles California, U.S.A
| | - Aria Fallah
- Department of Neurosurgery David Geffen School of Medicine at University of California Los Angeles Los Angeles California, U.S.A
| | - Harry V Vinters
- Section of Neuropathology Department of Pathology and Laboratory Medicine and Department of Neurology David Geffen School of Medicine at University of California Los Angeles Los Angeles California, U.S.A
| | - Michael S Levine
- IDDRC Semel Institute for Neuroscience and Human Behavior UCLA School of Medicine University of California Los Angeles Los Angeles California, U.S.A
| | - Joyce Y Wu
- Division of Pediatric Neurology Mattel Children's Hospital David Geffen School of Medicine at University of California Los Angeles Los Angeles California U.S.A
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22
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Abstract
The mechanistic target of rapamycin (mTOR) is an important signaling hub that integrates environmental information regarding energy availability and stimulates anabolic molecular processes and cell growth. Abnormalities in this pathway have been identified in several syndromes in which autism spectrum disorder (ASD) is highly prevalent. Several studies have investigated mTOR signaling in developmental and neuronal processes that, when dysregulated, could contribute to the development of ASD. Although many potential mechanisms still remain to be fully understood, these associations are of great interest because of the clinical availability of mTOR inhibitors. Clinical trials evaluating the efficacy of mTOR inhibitors to improve neurodevelopmental outcomes have been initiated.
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Affiliation(s)
- Kellen D. Winden
- F.M. Kirby Neurobiology Center, Translational Neuroscience Center, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Darius Ebrahimi-Fakhari
- F.M. Kirby Neurobiology Center, Translational Neuroscience Center, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Mustafa Sahin
- F.M. Kirby Neurobiology Center, Translational Neuroscience Center, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA
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23
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Curatolo P, Moavero R, van Scheppingen J, Aronica E. mTOR dysregulation and tuberous sclerosis-related epilepsy. Expert Rev Neurother 2018; 18:185-201. [DOI: 10.1080/14737175.2018.1428562] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Paolo Curatolo
- Child Neurology and Psychiatry Unit, Systems Medicine Department, Tor Vergata University Hospital, Rome, Italy
| | - Romina Moavero
- Child Neurology and Psychiatry Unit, Systems Medicine Department, Tor Vergata University Hospital, Rome, Italy
- Child Neurology Unit, Neuroscience and Neurorehabilitation Department, “Bambino Gesù” Children’s Hospital, IRCCS, Rome, Italy
| | - Jackelien van Scheppingen
- Department of (Neuro)Pathology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Eleonora Aronica
- Department of (Neuro)Pathology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
- Stichting Epilepsie Instellingen Nederland (SEIN), The Netherlands
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24
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Magdalon J, Sánchez-Sánchez SM, Griesi-Oliveira K, Sertié AL. Dysfunctional mTORC1 Signaling: A Convergent Mechanism between Syndromic and Nonsyndromic Forms of Autism Spectrum Disorder? Int J Mol Sci 2017; 18:ijms18030659. [PMID: 28335463 PMCID: PMC5372671 DOI: 10.3390/ijms18030659] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2017] [Revised: 03/13/2017] [Accepted: 03/14/2017] [Indexed: 12/28/2022] Open
Abstract
Whereas autism spectrum disorder (ASD) exhibits striking heterogeneity in genetics and clinical presentation, dysfunction of mechanistic target of rapamycin complex 1 (mTORC1) signaling pathway has been identified as a molecular feature common to several well-characterized syndromes with high prevalence of ASD. Additionally, recent findings have also implicated mTORC1 signaling abnormalities in a subset of nonsyndromic ASD, suggesting that defective mTORC1 pathway may be a potential converging mechanism in ASD pathology across different etiologies. However, the mechanistic evidence for a causal link between aberrant mTORC1 pathway activity and ASD neurobehavioral features varies depending on the ASD form involved. In this review, we first discuss six monogenic ASD-related syndromes, including both classical and potentially novel mTORopathies, highlighting their contribution to our understanding of the neurobiological mechanisms underlying ASD, and then we discuss existing evidence suggesting that aberrant mTORC1 signaling may also play a role in nonsyndromic ASD.
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Affiliation(s)
- Juliana Magdalon
- Hospital Israelita Albert Einstein, Centro de Pesquisa Experimental, São Paulo 05652-900, Brazil.
| | - Sandra M Sánchez-Sánchez
- Hospital Israelita Albert Einstein, Centro de Pesquisa Experimental, São Paulo 05652-900, Brazil.
- Departamento de Genética e Biologia Evolutiva, Instituto de Biociências, Universidade de São Paulo, São Paulo 05508-090, Brazil.
| | - Karina Griesi-Oliveira
- Hospital Israelita Albert Einstein, Centro de Pesquisa Experimental, São Paulo 05652-900, Brazil.
| | - Andréa L Sertié
- Hospital Israelita Albert Einstein, Centro de Pesquisa Experimental, São Paulo 05652-900, Brazil.
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25
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Stafstrom CE, Staedtke V, Comi AM. Epilepsy Mechanisms in Neurocutaneous Disorders: Tuberous Sclerosis Complex, Neurofibromatosis Type 1, and Sturge-Weber Syndrome. Front Neurol 2017; 8:87. [PMID: 28367137 PMCID: PMC5355446 DOI: 10.3389/fneur.2017.00087] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Accepted: 02/24/2017] [Indexed: 01/27/2023] Open
Abstract
Neurocutaneous disorders are multisystem diseases affecting skin, brain, and other organs. Epilepsy is very common in the neurocutaneous disorders, affecting up to 90% of patients with tuberous sclerosis complex (TSC) and Sturge–Weber syndrome (SWS), for example. The mechanisms underlying the increased predisposition to brain hyperexcitability differ between disorders, yet some molecular pathways overlap. For instance, the mechanistic target of rapamycin (mTOR) signaling cascade plays a central role in seizures and epileptogenesis in numerous acquired and genetic disorders, including several neurocutaneous disorders. Potential routes for target-specific treatments are emerging as the genetic and molecular pathways involved in neurocutaneous disorders become increasingly understood. This review explores the clinical features and mechanisms of epilepsy in three common neurocutaneous disorders—TSC, neurofibromatosis type 1, and SWS.
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Affiliation(s)
- Carl E Stafstrom
- Division of Pediatric Neurology, Department of Neurology, Johns Hopkins University School of Medicine , Baltimore, MD , USA
| | - Verena Staedtke
- Division of Pediatric Neurology, Department of Neurology, Johns Hopkins University School of Medicine , Baltimore, MD , USA
| | - Anne M Comi
- Department of Neurology, Kennedy Krieger Institute, Johns Hopkins University School of Medicine , Baltimore, MD , USA
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26
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Abstract
Epilepsy is one of the most common neurologic disorders, affecting about 50 million people worldwide. The disease is characterized by recurrent seizures, which are due to aberrant neuronal networks resulting in synchronous discharges. The term epilepsy encompasses a large spectrum of syndromes and diseases with different etiopathogenesis. The recent development of imaging and epilepsy surgery techniques is now enabling the identification of structural abnormalities that are part of the epileptic network, and the removal of these lesions may result in control of seizures. Access of this clinically well-characterized neurosurgical material has provided neuropathologists with the opportunity to study a variety of structural brain abnormalities associated with epilepsy, by combining traditional routine histopathologic methods with molecular genetics and functional analysis of the resected tissue. This approach has contributed greatly to a better diagnosis and classification of these structural lesions, and has provided important new insights into their pathogenesis and epileptogenesis. The present chapter provides a detailed description of the large spectrum of histopathologic findings encountered in epilepsy surgery patients, addressing in particular the nonneoplastic pathologies, including hippocampal sclerosis, malformations of cortical development, Sturge-Weber syndrome, and Rasmussen encephalitis, and reviews current knowledge regarding the underlying molecular pathomechanisms and cellular mechanisms mediating hyperexcitability.
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Affiliation(s)
- Eleonora Aronica
- Department of Neuropathology, Academic Medical Center and Swammerdam Institute for Life Sciences, Center for Neuroscience, University of Amsterdam, Amsterdam, the Netherlands; Stichting Epilepsie Instellingen Nederland, the Netherlands.
| | - Angelika Mühlebner
- Department of Neuropathology, Academic Medical Center and Swammerdam Institute for Life Sciences, Center for Neuroscience, University of Amsterdam, Amsterdam, the Netherlands
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27
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Functional aspects of early brain development are preserved in tuberous sclerosis complex (TSC) epileptogenic lesions. Neurobiol Dis 2016; 95:93-101. [DOI: 10.1016/j.nbd.2016.07.014] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Revised: 07/05/2016] [Accepted: 07/13/2016] [Indexed: 02/04/2023] Open
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28
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The mTOR signalling cascade: paving new roads to cure neurological disease. Nat Rev Neurol 2016; 12:379-92. [PMID: 27340022 DOI: 10.1038/nrneurol.2016.81] [Citation(s) in RCA: 251] [Impact Index Per Article: 31.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Defining the multiple roles of the mechanistic (formerly 'mammalian') target of rapamycin (mTOR) signalling pathway in neurological diseases has been an exciting and rapidly evolving story of bench-to-bedside translational research that has spanned gene mutation discovery, functional experimental validation of mutations, pharmacological pathway manipulation, and clinical trials. Alterations in the dual contributions of mTOR - regulation of cell growth and proliferation, as well as autophagy and cell death - have been found in developmental brain malformations, epilepsy, autism and intellectual disability, hypoxic-ischaemic and traumatic brain injuries, brain tumours, and neurodegenerative disorders. mTOR integrates a variety of cues, such as growth factor levels, oxygen levels, and nutrient and energy availability, to regulate protein synthesis and cell growth. In line with the positioning of mTOR as a pivotal cell signalling node, altered mTOR activation has been associated with a group of phenotypically diverse neurological disorders. To understand how altered mTOR signalling leads to such divergent phenotypes, we need insight into the differential effects of enhanced or diminished mTOR activation, the developmental context of these changes, and the cell type affected by altered signalling. A particularly exciting feature of the tale of mTOR discovery is that pharmacological mTOR inhibitors have shown clinical benefits in some neurological disorders, such as tuberous sclerosis complex, and are being considered for clinical trials in epilepsy, autism, dementia, traumatic brain injury, and stroke.
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29
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Early onset epileptic encephalopathy or genetically determined encephalopathy with early onset epilepsy? Lessons learned from TSC. Eur J Paediatr Neurol 2016; 20:203-211. [PMID: 26758984 DOI: 10.1016/j.ejpn.2015.12.005] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Revised: 12/01/2015] [Accepted: 12/13/2015] [Indexed: 01/12/2023]
Abstract
BACKGROUND In tuberous sclerosis complex (TSC) a relationship has been shown between early and refractory seizures and intellectual disability. However, it is uncertain whether epilepsy in TSC is simply a marker in infants who are destined to develop an encephalopathic process or if seizures play a causal role in developing an encephalopathy. METHODS This paper summarizes the key points discussed during a European TSC workshop held in Rome, and reviews the experimental and clinical evidence in support of the two theories. RESULTS/CONCLUSION There are many factors that influence the appearance of both early seizure onset and the encephalopathy resulting in neurodevelopmental deficits. Experimental studies show that as a consequence of the TSC genes mutation, mammalian target of Rapamycin (mTOR) overactivation determines an alteration in cellular morphology with cytomegalic neurons, altered synaptogenesis and an imbalance between excitation/inhibition, thus providing a likely neuroanatomical substrate for the early appearance of refractory seizures and for the encephalopathic process. At the clinical level, early signs of altered developmental trajectories are often unrecognized before 12 months of age. Evidence from experimental research shows that encephalopathy in TSC might have a genetic cause, and mTOR activation caused by TSC gene mutation can be directly responsible for the early appearance of seizures and encephalopathy.
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30
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Deletion of mTOR in Reactive Astrocytes Suppresses Chronic Seizures in a Mouse Model of Temporal Lobe Epilepsy. Mol Neurobiol 2016; 54:175-187. [PMID: 26732600 DOI: 10.1007/s12035-015-9590-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Accepted: 11/29/2015] [Indexed: 01/28/2023]
Abstract
Germline and somatic mutations in key genes of the mammalian target of rapamycin (mTOR) pathway have been identified in seizure-associated disorders. mTOR mutations lead to aberrant activation of mTOR signaling, and, although affected neurons are critical for epileptogenesis, the role of mTOR activation in glial cells remains poorly understood. We previously reported a consistent activation of the mTOR pathway in astrocytes in the epileptic foci of temporal lobe epilepsy. In this study, it was demonstrated that mTOR deletion from reactive astrocytes prevents increases in seizure frequency over the disease course. By using a tamoxifen-inducible mTOR conditional knockout system and kainic acid, a model was developed that allowed astrocyte-specific mTOR gene deletion in mice with chronic epilepsy. Animals in which mTOR was deleted from 44 % of the astrocyte population exhibited a lower seizure frequency compared with controls. Down-regulation of mTOR significantly ameliorated astrogliosis in the sclerotic hippocampus but did not rescue mossy fiber sprouting. In cultured astrocytes, the mTOR pathway modulated the stability of the astroglial glutamate transporter 1 (Glt1) and influenced the ability of astrocytes to remove extracellular glutamate. Taken together, these data indicate that astrocytes with activated mTOR signaling may provide conditions that are favorable for spontaneous recurrent seizures.
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31
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Galanopoulou AS, Moshé SL. Neonatal and Infantile Epilepsy: Acquired and Genetic Models. Cold Spring Harb Perspect Med 2015; 6:a022707. [PMID: 26637437 DOI: 10.1101/cshperspect.a022707] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The incidence of seizures and epilepsies is particularly high during the neonatal and infantile periods. We will review selected animal models of early-life epileptic encephalopathies that have addressed the dyscognitive features of frequent interictal spikes, the pathogenesis and treatments of infantile spasms (IS) or Dravet syndrome, disorders with mammalian target of rapamycin (mTOR) dysregulation, and selected early-life epilepsies with genetic defects. Potentially pathogenic mechanisms in these conditions include interneuronopathies in IS or Dravet syndrome and mTOR dysregulation in brain malformations, tuberous sclerosis, and related genetic disorders, or IS of acquired etiology. These models start to generate the first therapeutic drugs, which have been specifically developed in immature animals. However, there are challenges in translating preclinical discoveries into clinically relevant findings. The advances made so far hold promise that the new insights may potentially have curative or disease-modifying potential for many of these devastating conditions.
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Affiliation(s)
- Aristea S Galanopoulou
- Saul R. Korey Department of Neurology, Dominick P. Purpura Department of Neuroscience, Laboratory of Developmental Epilepsy, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, New York 10461
| | - Solomon L Moshé
- Saul R. Korey Department of Neurology, Dominick P. Purpura Department of Neuroscience, Laboratory of Developmental Epilepsy, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, New York 10461 Department of Pediatrics, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, New York 10461
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32
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Abstract
TOR (target of rapamycin) and its mammalian ortholog mTOR have been discovered in an effort to understand the mechanisms of action of the immunosuppressant drug rapamycin extracted from a bacterium of the Easter Island (Rapa Nui) soil. mTOR is a serine/threonine kinase found in two functionally distinct complexes, mTORC1 and mTORC2, which are differentially regulated by a great number of nutrients such as glucose and amino acids, energy (oxygen and ATP/AMP content), growth factors, hormones, and neurotransmitters. mTOR controls many basic cellular functions such as protein synthesis, energy metabolism, cell size, lipid metabolism, autophagy, mitochondria, and lysosome biogenesis. In addition, mTOR-controlled signaling pathways regulate many integrated physiological functions of the nervous system including neuronal development, synaptic plasticity, memory storage, and cognition. Thus it is not surprising that deregulation of mTOR signaling is associated with many neurological and psychiatric disorders. Preclinical and preliminary clinical studies indicate that inhibition of mTORC1 can be beneficial for some pathological conditions such as epilepsy, cognitive impairment, and brain tumors, whereas stimulation of mTORC1 (direct or indirect) can be beneficial for other pathologies such as depression or axonal growth and regeneration.
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Affiliation(s)
- Joël Bockaert
- Centre National de la Recherche Scientifique, UMR-5203, Institut de Génomique Fonctionnelle, Montpellier, France; Institut National de la Santé et de la Recherche Médicale U1191, Montpellier, France; and Université de Montpellier, UMR-5203, Montpellier, France
| | - Philippe Marin
- Centre National de la Recherche Scientifique, UMR-5203, Institut de Génomique Fonctionnelle, Montpellier, France; Institut National de la Santé et de la Recherche Médicale U1191, Montpellier, France; and Université de Montpellier, UMR-5203, Montpellier, France
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33
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Complex Neurological Phenotype in Mutant Mice Lacking Tsc2 in Excitatory Neurons of the Developing Forebrain(123). eNeuro 2015; 2:eN-NWR-0046-15. [PMID: 26693177 PMCID: PMC4676199 DOI: 10.1523/eneuro.0046-15.2015] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Revised: 09/09/2015] [Accepted: 09/14/2015] [Indexed: 11/25/2022] Open
Abstract
Mutations in the TSC1 and TSC2 genes cause tuberous sclerosis complex (TSC), a genetic disease often associated with epilepsy, intellectual disability, and autism, and characterized by the presence of anatomical malformations in the brain as well as tumors in other organs. The TSC1 and TSC2 proteins form a complex that inhibits mammalian target of rapamycin complex 1 (mTORC1) signaling. Previous animal studies demonstrated that Tsc1 or Tsc2 loss of function in the developing brain affects the intrinsic development of neural progenitor cells, neurons, or glia. However, the interplay between different cellular elements during brain development was not previously investigated. In this study, we generated a novel mutant mouse line (NEX-Tsc2) in which the Tsc2 gene is deleted specifically in postmitotic excitatory neurons of the developing forebrain. Homozygous mutant mice failed to thrive and died prematurely, whereas heterozygous mice appeared normal. Mutant mice exhibited distinct neuroanatomical abnormalities, including malpositioning of selected neuronal populations, neuronal hypertrophy, and cortical astrogliosis. Intrinsic neuronal defects correlated with increased mTORC1 signaling, whereas astrogliosis did not result from altered intrinsic signaling, since these cells were not directly affected by the gene knockout strategy. All neuronal and non-neuronal abnormalities were suppressed by continuous postnatal treatment with the mTORC1 inhibitor RAD001. The data suggest that the loss of Tsc2 and mTORC1 signaling activation in excitatory neurons not only disrupts their intrinsic development, but also disrupts the development of cortical astrocytes, likely through the mTORC1-dependent expression of abnormal signaling proteins. This work thus provides new insights into cell-autonomous and non-cell-autonomous functions of Tsc2 in brain development.
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34
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Natarajan R, Barber K, Buckley A, Cho P, Egbejimi A, Wairkar YP. Tricornered Kinase Regulates Synapse Development by Regulating the Levels of Wiskott-Aldrich Syndrome Protein. PLoS One 2015; 10:e0138188. [PMID: 26393506 PMCID: PMC4578898 DOI: 10.1371/journal.pone.0138188] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Accepted: 08/26/2015] [Indexed: 11/19/2022] Open
Abstract
Precise regulation of synapses during development is essential to ensure accurate neural connectivity and function of nervous system. Many signaling pathways, including the mTOR (mechanical Target of Rapamycin) pathway operate in neurons to maintain genetically determined number of synapses during development. mTOR, a kinase, is shared between two functionally distinct multi-protein complexes- mTORC1 and mTORC2, that act downstream of Tuberous Sclerosis Complex (TSC). We and others have suggested an important role for TSC in synapse development at the Drosophila neuromuscular junction (NMJ) synapses. In addition, our data suggested that the regulation of the NMJ synapse numbers in Drosophila largely depends on signaling via mTORC2. In the present study, we further this observation by identifying Tricornered (Trc) kinase, a serine/threonine kinase as a likely mediator of TSC signaling. trc genetically interacts with Tsc2 to regulate the number of synapses. In addition, Tsc2 and trc mutants exhibit a dramatic reduction in synaptic levels of WASP, an important regulator of actin polymerization. We show that Trc regulates the WASP levels largely, by regulating the transcription of WASP. Finally, we show that overexpression of WASP (Wiskott-Aldrich Syndrome Protein) in trc mutants can suppress the increase in the number of synapses observed in trc mutants, suggesting that WASP regulates synapses downstream of Trc. Thus, our data provide a novel insight into how Trc may regulate the genetic program that controls the number of synapses during development.
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Affiliation(s)
- Rajalaxmi Natarajan
- Department of Neurology and Mitchell Center for Neurodegenerative Diseases, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Kara Barber
- Neuroscience Graduate Program, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Amanda Buckley
- Department of Neurology and Mitchell Center for Neurodegenerative Diseases, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Phillip Cho
- Summer Undergraduate Research Program, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Anuoluwapo Egbejimi
- Department of Neurology, University of Texas Medical Branch, Galveston, Texas, United States of America
- Neuroscience Graduate Program, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Yogesh P. Wairkar
- Department of Neurology and Mitchell Center for Neurodegenerative Diseases, University of Texas Medical Branch, Galveston, Texas, United States of America
- Department of Neuroscience and Cell Biology, University of Texas Medical Branch, Galveston, Texas, United States of America
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35
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Fallah A, Rodgers SD, Weil AG, Vadera S, Mansouri A, Connolly MB, Major P, Ma T, Devinsky O, Weiner HL, Gonzalez-Martinez JA, Bingaman WE, Najm I, Gupta A, Ragheb J, Bhatia S, Steinbok P, Witiw CD, Widjaja E, Snead OC, Rutka JT. Resective Epilepsy Surgery for Tuberous Sclerosis in Children. Neurosurgery 2015; 77:517-24; discussion 524. [DOI: 10.1227/neu.0000000000000875] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Abstract
BACKGROUND:
There are no established variables that predict the success of curative resective epilepsy surgery in children with tuberous sclerosis complex (TSC).
OBJECTIVE:
We performed a multicenter observational study to identify preoperative factors associated with seizure outcome in children with TSC undergoing resective epilepsy surgery.
METHODS:
A retrospective chart review was performed in eligible children at New York Medical Center, Miami Children's Hospital, Cleveland Clinic Foundation, BC Children's Hospital, Hospital for Sick Children, and Sainte-Justine Hospital between January 2005 and December 2013. A time-to-event analysis was performed. The “event” was defined as seizures after resective epilepsy surgery.
RESULTS:
Seventy-four patients (41 male) were included. The median age of the patients at the time of surgery was 120 months (range, 3-216 months). The median time to seizure recurrence was 24.0 ± 12.7 months. Engel Class I outcome was achieved in 48 (65%) and 37 (50%) patients at 1- and 2-year follow-up, respectively. On univariate analyses, younger age at seizure onset (hazard ratio [HR]: 2.03, 95% confidence interval [CI]: 1.03-4.00, P = .04), larger size of predominant tuber (HR: 1.03, 95% CI: 0.99-1.06, P = .12), and resection larger than a tuberectomy (HR: 1.86, 95% CI: 0.92-3.74, P = .084) were associated with a longer duration of seizure freedom. In multivariate analyses, resection larger than a tuberectomy (HR: 2.90, 95% CI: 1.17-7.18, P = .022) was independently associated with a longer duration of seizure freedom.
CONCLUSION:
In this large consecutive cohort of children with TSC and medically intractable epilepsy, a greater extent of resection (more than just the tuber) is associated with a greater probability of seizure freedom. This suggests that the epileptogenic zone may include the cortex surrounding the presumed offending tuber.
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Affiliation(s)
- Aria Fallah
- Department of Neurosurgery, Miami Children's Hospital, Miami, Florida
- Department of Clinical Epidemiology and Biostatistics, McMaster University, Hamilton, ON, Canada
| | - Shaun D. Rodgers
- Department of Neurosurgery, New York University Langone Medical Center, New York, New York
| | - Alexander G. Weil
- Department of Neurosurgery, Miami Children's Hospital, Miami, Florida
| | - Sumeet Vadera
- Department of Neurosurgery, Cleveland Clinic Foundation, Cleveland, Ohio
| | - Alireza Mansouri
- Division of Neurosurgery, The Hospital for Sick Children, Toronto, ON, Canada
| | - Mary B. Connolly
- Division of Neurology, BC Children's Hospital, Vancouver, BC, Canada
| | - Philippe Major
- Division of Neurology, CHU Sainte-Justine, Montreal, QC, Canada
| | - Tracy Ma
- Department of Neurosurgery, University of Pennsylvania Health System, Philadelphia, Pennsylvania
| | - Orrin Devinsky
- Department of Neurology, New York University Langone Medical Center, New York, New York
| | - Howard L. Weiner
- Department of Neurosurgery, New York University Langone Medical Center, New York, New York
| | | | | | - Imad Najm
- Department of Neurology, New York University Langone Medical Center, New York, New York
| | - Ajay Gupta
- Department of Neurology, New York University Langone Medical Center, New York, New York
| | - John Ragheb
- Department of Neurosurgery, Miami Children's Hospital, Miami, Florida
| | - Sanjiv Bhatia
- Department of Neurosurgery, Miami Children's Hospital, Miami, Florida
| | - Paul Steinbok
- Department of Neurology, Cleveland Clinic Foundation, Cleveland, Ohio
| | | | - Elysa Widjaja
- Division of Neurosurgery, BC Children's Hospital, Vancouver, BC, Canada
| | - O. Carter Snead
- Department of Diagnostic Imaging, The Hospital for Sick Children, Toronto, ON, Canada
| | - James T. Rutka
- Division of Neurosurgery, The Hospital for Sick Children, Toronto, ON, Canada
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Sosunov AA, McGovern RA, Mikell CB, Wu X, Coughlin DG, Crino PB, Weiner HL, Ghatan S, Goldman JE, McKhann GM. Epileptogenic but MRI-normal perituberal tissue in Tuberous Sclerosis Complex contains tuber-specific abnormalities. Acta Neuropathol Commun 2015; 3:17. [PMID: 25853525 PMCID: PMC4383198 DOI: 10.1186/s40478-015-0191-5] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Accepted: 02/03/2015] [Indexed: 01/08/2023] Open
Abstract
INTRODUCTION Recent evidence has implicated perituberal, MRI-normal brain tissue as a possible source of seizures in tuberous sclerosis complex (TSC). Data on aberrant structural features in this area that may predispose to the initiation or progression of seizures are very limited. We used immunohistochemistry and confocal microscopy to compare epileptogenic, perituberal, MRI-normal tissue with cortical tubers. RESULTS In every sample of epileptogenic, perituberal tissue, we found many abnormal cell types, including giant cells and cytomegalic neurons. The majority of giant cells were surrounded by morphologically abnormal astrocytes with long processes typical of interlaminar astrocytes. Perituberal giant cells and astrocytes together formed characteristic "microtubers". A parallel analysis of tubers showed that many contained astrocytes with features of both protoplasmic and gliotic cells. CONCLUSIONS Microtubers represent a novel pathognomonic finding in TSC and may represent an elementary unit of cortical tubers. Microtubers and cytomegalic neurons in perituberal parenchyma may serve as the source of seizures in TSC and provide potential targets for therapeutic and surgical interventions in TSC.
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Grone BP, Baraban SC. Animal models in epilepsy research: legacies and new directions. Nat Neurosci 2015; 18:339-43. [PMID: 25710835 DOI: 10.1038/nn.3934] [Citation(s) in RCA: 159] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Accepted: 12/21/2014] [Indexed: 12/16/2022]
Abstract
Human epilepsies encompass a wide variety of clinical, behavioral and electrical manifestations. Correspondingly, studies of this disease in nonhuman animals have brought forward an equally wide array of animal models; that is, species and acute or chronic seizure induction protocols. Epilepsy research has a long history of comparative anatomical and physiological studies on a range of mostly mammalian species. Nonetheless, a relatively limited number of rodent models have emerged as the primary choices for most investigations. In many cases, these animal models are selected on the basis of convenience or tradition, although technical or experimental rationale does, and should, factor into these decisions. More complex mammalian brains and genetic model organisms including zebrafish have been studied less, but offer substantial advantages that are becoming widely recognized.
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Affiliation(s)
- Brian P Grone
- Department of Neurological Surgery, University of California, San Francisco, California, USA
| | - Scott C Baraban
- Department of Neurological Surgery, University of California, San Francisco, California, USA
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Marin-Valencia I, Guerrini R, Gleeson JG. Pathogenetic mechanisms of focal cortical dysplasia. Epilepsia 2014; 55:970-8. [PMID: 24861491 PMCID: PMC4107035 DOI: 10.1111/epi.12650] [Citation(s) in RCA: 75] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/04/2014] [Indexed: 02/01/2023]
Abstract
Focal cortical dysplasias (FCDs) constitute a prevalent cause of intractable epilepsy in children, and is one of the leading conditions requiring epilepsy surgery. Despite recent advances in the cellular and molecular biology of these conditions, the pathogenetic mechanisms of FCDs remain largely unknown. The purpose if this work is to review the molecular underpinnings of FCDs and to highlight potential therapeutic targets. A systematic review of the literature regarding the histologic, molecular, and electrophysiologic aspects of FCDs was conducted. Disruption of the mammalian target of rapamycin (mTOR) signaling comprises a common pathway underlying the structural and electrical disturbances of some FCDs. Other mechanisms such as viral infections, prematurity, head trauma, and brain tumors are also posited. mTOR inhibitors (i.e., rapamycin) have shown positive results on seizure management in animal models and in a small cohort of patients with FCD. Encouraging progress has been achieved on the molecular and electrophysiologic basis of constitutive cells in the dysplastic tissue. Despite the promising results of mTOR inhibitors, large-scale randomized trials are in need to evaluate their efficacy and side effects, along with additional mechanistic studies for the development of novel, molecular-based diagnostic and therapeutic approaches.
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Affiliation(s)
- Isaac Marin-Valencia
- Department of Neurology and Neurotherapeutics, and Pediatrics, University of Texas Southwestern Medical Center, Dallas, Texas, U.S.A
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39
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Giannantoni NM, Restuccia D, Della Marca G, Alfano RM, Vollono C. A novel TSC2 mutation causing tuberless tuberous sclerosis. Seizure 2014; 23:580-2. [PMID: 24794161 DOI: 10.1016/j.seizure.2014.04.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2014] [Revised: 03/03/2014] [Accepted: 04/01/2014] [Indexed: 10/25/2022] Open
Affiliation(s)
| | - Domenico Restuccia
- Institute of Neurology, Unit of Neurophysiology and Sleep Medicine, Catholic University, Rome, Italy
| | - Giacomo Della Marca
- Institute of Neurology, Unit of Neurophysiology and Sleep Medicine, Catholic University, Rome, Italy
| | - Rosa Maria Alfano
- Unit of Human Pathology, Department of Health Science San Paolo Hospital, Milan, Italy
| | - Catello Vollono
- Institute of Neurology, Unit of Neurophysiology and Sleep Medicine, Catholic University, Rome, Italy
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40
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Aronica E, Crino PB. Epilepsy related to developmental tumors and malformations of cortical development. Neurotherapeutics 2014; 11:251-68. [PMID: 24481729 PMCID: PMC3996119 DOI: 10.1007/s13311-013-0251-0] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Structural abnormalities of the brain are increasingly recognized in patients with neurodevelopmental delay and intractable focal epilepsies. The access to clinically well-characterized neurosurgical material has provided a unique opportunity to better define the neuropathological, neurochemical, and molecular features of epilepsy-associated focal developmental lesions. These studies help to further understand the epileptogenic mechanisms of these lesions. Neuropathological evaluation of surgical specimens from patients with epilepsy-associated developmental lesions reveals two major pathologies: focal cortical dysplasia and low-grade developmental tumors (glioneuronal tumors). In the last few years there have been major advances in the recognition of a wide spectrum of developmental lesions associated with a intractable epilepsy, including cortical tubers in patients with tuberous sclerosis complex and hemimegalencephaly. As an increasing number of entities are identified, the development of a unified and comprehensive classification represents a great challenge and requires continuous updates. The present article reviews current knowledge of molecular pathogenesis and the pathophysiological mechanisms of epileptogenesis in this group of developmental disorders. Both emerging neuropathological and basic science evidence will be analyzed, highlighting the involvement of different, but often converging, pathogenetic and epileptogenic mechanisms, which may create the basis for new therapeutic strategies in these disorders.
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Affiliation(s)
- Eleonora Aronica
- Department of (Neuro)Pathology, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105, AZ, Amsterdam, The Netherlands,
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41
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Hunold A, Haueisen J, Ahtam B, Doshi C, Harini C, Camposano S, Warfield SK, Grant PE, Okada Y, Papadelis C. Localization of the epileptogenic foci in tuberous sclerosis complex: a pediatric case report. Front Hum Neurosci 2014; 8:175. [PMID: 24723876 PMCID: PMC3972469 DOI: 10.3389/fnhum.2014.00175] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2013] [Accepted: 03/10/2014] [Indexed: 12/20/2022] Open
Abstract
Tuberous sclerosis complex (TSC) is a rare disorder of tissue growth and differentiation, characterized by benign hamartomas in the brain and other organs. Up to 90% of TSC patients develop epilepsy and 50% become medically intractable requiring resective surgery. The surgical outcome of TSC patients depends on the accurate identification of the epileptogenic zone consisting of tubers and the surrounding epileptogenic tissue. There is conflicting evidence whether the epileptogenic zone is in the tuber itself or in abnormally developed surrounding cortex. Here, we report the localization of the epileptiform activity among the many cortical tubers in a 4-year-old patient with TSC-related refractory epilepsy undergoing magnetoencephalography (MEG), electroencephalography (EEG), and diffusion tensor imaging (DTI). For MEG, we used a prototype system that offers higher spatial resolution and sensitivity compared to the conventional adult systems. The generators of interictal activity were localized using both EEG and MEG with equivalent current dipole (ECD) and minimum norm estimation (MNE) methods according to the current clinical standards. For DTI, we calculated four diffusion scalar parameters for the fibers passing through four ROIs defined: (i) at a large cortical tuber identified at the right quadrant, (ii) at the normal appearing tissue contralateral to the tuber, (iii) at the cluster formed by ECDs fitted at the peak of interictal spikes, and (iv) at the normal appearing tissue contralateral to the cluster. ECDs were consistently clustered at the vicinity of the large calcified cortical tuber. MNE and ECDs indicated epileptiform activity in the same areas. DTI analysis showed differences between the scalar values of the tracks passing through the tuber and the ECD cluster. In this illustrative case, we provide evidence from different neuroimaging modalities, which support the view that epileptiform activity may derive from abnormally developed tissue surrounding the tuber rather than the tuber itself.
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Affiliation(s)
- Alexander Hunold
- Institute of Biomedical Engineering and Informatics, Ilmenau University of Technology , Ilmenau , Germany
| | - Jens Haueisen
- Institute of Biomedical Engineering and Informatics, Ilmenau University of Technology , Ilmenau , Germany
| | - Banu Ahtam
- Fetal-Neonatal Neuroimaging and Developmental Science Center, Boston Children's Hospital, Harvard Medical School , Boston, MA , USA ; Department of Newborn Medicine, Boston Children's Hospital, Harvard Medical School , Boston, MA , USA
| | - Chiran Doshi
- Fetal-Neonatal Neuroimaging and Developmental Science Center, Boston Children's Hospital, Harvard Medical School , Boston, MA , USA ; Department of Neurology, Boston Children's Hospital, Harvard Medical School , Boston, MA , USA
| | - Chellamani Harini
- Department of Neurology, Boston Children's Hospital, Harvard Medical School , Boston, MA , USA
| | - Susana Camposano
- Department of Neurology, Boston Children's Hospital, Harvard Medical School , Boston, MA , USA
| | - Simon K Warfield
- Department of Radiology, Boston Children's Hospital, Harvard Medical School , Boston, MA , USA ; Computational Radiology Laboratory, Boston Children's Hospital, Harvard Medical School , Boston, MA , USA
| | - Patricia Ellen Grant
- Fetal-Neonatal Neuroimaging and Developmental Science Center, Boston Children's Hospital, Harvard Medical School , Boston, MA , USA ; Department of Newborn Medicine, Boston Children's Hospital, Harvard Medical School , Boston, MA , USA ; Department of Radiology, Boston Children's Hospital, Harvard Medical School , Boston, MA , USA
| | - Yoshio Okada
- Fetal-Neonatal Neuroimaging and Developmental Science Center, Boston Children's Hospital, Harvard Medical School , Boston, MA , USA ; Department of Neurology, Boston Children's Hospital, Harvard Medical School , Boston, MA , USA
| | - Christos Papadelis
- Fetal-Neonatal Neuroimaging and Developmental Science Center, Boston Children's Hospital, Harvard Medical School , Boston, MA , USA ; Department of Neurology, Boston Children's Hospital, Harvard Medical School , Boston, MA , USA
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42
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Lasarge CL, Danzer SC. Mechanisms regulating neuronal excitability and seizure development following mTOR pathway hyperactivation. Front Mol Neurosci 2014; 7:18. [PMID: 24672426 PMCID: PMC3953715 DOI: 10.3389/fnmol.2014.00018] [Citation(s) in RCA: 123] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2014] [Accepted: 02/27/2014] [Indexed: 01/19/2023] Open
Abstract
The phosphatidylinositol-3-kinase/phosphatase and tensin homolog (PTEN)-mammalian target of rapamycin (mTOR) pathway regulates a variety of neuronal functions, including cell proliferation, survival, growth, and plasticity. Dysregulation of the pathway is implicated in the development of both genetic and acquired epilepsies. Indeed, several causal mutations have been identified in patients with epilepsy, the most prominent of these being mutations in PTEN and tuberous sclerosis complexes 1 and 2 (TSC1, TSC2). These genes act as negative regulators of mTOR signaling, and mutations lead to hyperactivation of the pathway. Animal models deleting PTEN, TSC1, and TSC2 consistently produce epilepsy phenotypes, demonstrating that increased mTOR signaling can provoke neuronal hyperexcitability. Given the broad range of changes induced by altered mTOR signaling, however, the mechanisms underlying seizure development in these animals remain uncertain. In transgenic mice, cell populations with hyperactive mTOR have many structural abnormalities that support recurrent circuit formation, including somatic and dendritic hypertrophy, aberrant basal dendrites, and enlargement of axon tracts. At the functional level, mTOR hyperactivation is commonly, but not always, associated with enhanced synaptic transmission and plasticity. Moreover, these populations of abnormal neurons can affect the larger network, inducing secondary changes that may explain paradoxical findings reported between cell and network functioning in different models or at different developmental time points. Here, we review the animal literature examining the link between mTOR hyperactivation and epileptogenesis, emphasizing the impact of enhanced mTOR signaling on neuronal form and function.
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Affiliation(s)
- Candi L Lasarge
- Department of Anesthesia, Cincinnati Children's Hospital Medical Center Cincinnati, OH, USA
| | - Steve C Danzer
- Department of Anesthesia, Cincinnati Children's Hospital Medical Center Cincinnati, OH, USA ; Department of Anesthesia, University of Cincinnati Cincinnati, OH, USA ; Department of Pediatrics, University of Cincinnati Cincinnati, OH, USA
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43
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Ruppe V, Dilsiz P, Reiss CS, Carlson C, Devinsky O, Zagzag D, Weiner HL, Talos DM. Developmental brain abnormalities in tuberous sclerosis complex: A comparative tissue analysis of cortical tubers and perituberal cortex. Epilepsia 2014; 55:539-50. [DOI: 10.1111/epi.12545] [Citation(s) in RCA: 75] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/29/2013] [Indexed: 12/25/2022]
Affiliation(s)
- Véronique Ruppe
- Department of Neurology; School of Medicine; New York University; New York New York U.S.A
| | - Pelin Dilsiz
- Department of Neurology; School of Medicine; New York University; New York New York U.S.A
| | - Carol Shoshkes Reiss
- Department of Biology and Neural Science; New York University; New York New York U.S.A
| | - Chad Carlson
- Department of Neurology; School of Medicine; New York University; New York New York U.S.A
| | - Orrin Devinsky
- Department of Neurology; School of Medicine; New York University; New York New York U.S.A
- Department of Neurosurgery; School of Medicine; New York University; New York New York U.S.A
- Department of Psychiatry; School of Medicine; New York University; New York New York U.S.A
| | - David Zagzag
- Department of Neurosurgery; School of Medicine; New York University; New York New York U.S.A
- Department of Pathology; School of Medicine; New York University; New York New York U.S.A
| | - Howard L. Weiner
- Department of Neurosurgery; School of Medicine; New York University; New York New York U.S.A
| | - Delia M. Talos
- Department of Neurology; School of Medicine; New York University; New York New York U.S.A
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44
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Weston MC, Chen H, Swann JW. Loss of mTOR repressors Tsc1 or Pten has divergent effects on excitatory and inhibitory synaptic transmission in single hippocampal neuron cultures. Front Mol Neurosci 2014; 7:1. [PMID: 24574959 DOI: 10.3389/fnmol.2014.00001] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2013] [Accepted: 01/09/2014] [Indexed: 01/23/2023] Open
Abstract
The Pten and Tsc1 genes both encode proteins that repress mechanistic target of rapamycin (mTOR) signaling. Disruption of either gene in the brain results in epilepsy and autism-like symptoms in humans and mouse models, therefore it is important to understand the molecular and physiological events that lead from gene disruption to disease phenotypes. Given the similar roles these two molecules play in the regulation of cellular growth and the overlap in the phenotypes that result from their loss, we predicted that the deletion of either the Pten or Tsc1 gene from autaptic hippocampal neurons would have similar effects on neuronal morphology and synaptic transmission. Accordingly, we found that loss of either Pten or Tsc1 caused comparable increases in soma size, dendrite length and action potential properties. However, the effects of Pten and Tsc1 loss on synaptic transmission were different. Loss of Pten lead to an increase in both excitatory and inhibitory neurotransmission, while loss of Tsc1 did not affect excitatory neurotransmission and reduced inhibitory transmission by decreasing mIPSC amplitude. Although the loss of Pten or Tsc1 both increased downstream mTORC1 signaling, phosphorylation of Akt was increased in Pten-ko and decreased in Tsc1-ko neurons, potentially accounting for the different effects on synaptic transmission. Despite the different effects at the synaptic level, our data suggest that loss of Pten or Tsc1 may both lead to an increase in the ratio of excitation to inhibition at the network level, an effect that has been proposed to underlie both epilepsy and autism.
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Affiliation(s)
- Matthew C Weston
- The Cain Foundation Laboratories, The Jan and Dan Duncan Neurological Research Institute Houston, TX, USA ; Departments of Neuroscience and Pediatrics, Baylor College of Medicine Houston, TX, USA
| | - Hongmei Chen
- The Cain Foundation Laboratories, The Jan and Dan Duncan Neurological Research Institute Houston, TX, USA ; Departments of Neuroscience and Pediatrics, Baylor College of Medicine Houston, TX, USA
| | - John W Swann
- The Cain Foundation Laboratories, The Jan and Dan Duncan Neurological Research Institute Houston, TX, USA ; Departments of Neuroscience and Pediatrics, Baylor College of Medicine Houston, TX, USA
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45
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Curatolo P, D’Argenzio L, Cerminara C, Bombardieri R. Management of epilepsy in tuberous sclerosis complex. Expert Rev Neurother 2014; 8:457-67. [DOI: 10.1586/14737175.8.3.457] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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46
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mTOR complexes in neurodevelopmental and neuropsychiatric disorders. Nat Neurosci 2013; 16:1537-43. [PMID: 24165680 DOI: 10.1038/nn.3546] [Citation(s) in RCA: 259] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2013] [Accepted: 09/11/2013] [Indexed: 02/07/2023]
Abstract
The mechanistic target of rapamycin (mTOR) acts as a highly conserved signaling "hub" that integrates neuronal activity and a variety of synaptic inputs. mTOR is found in two functionally distinct complexes, mTORC1 and mTORC2, that crucially control long-term synaptic efficacy and memory storage. Dysregulation of mTOR signaling is associated with neurodevelopmental and neuropsychiatric disorders. In this Review, we describe the most recent advances in studies of mTOR signaling in the brain and the possible mechanisms underlying the many different functions of the mTOR complexes in neurological diseases. In addition, we discuss the medical relevance of these findings.
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47
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Westerholz S, de Lima AD, Voigt T. Thyroid hormone-dependent development of early cortical networks: temporal specificity and the contribution of trkB and mTOR pathways. Front Cell Neurosci 2013; 7:121. [PMID: 23964198 PMCID: PMC3734363 DOI: 10.3389/fncel.2013.00121] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2013] [Accepted: 07/10/2013] [Indexed: 11/17/2022] Open
Abstract
Early in neocortical network development, triiodothyronine (T3) promotes GABAergic neurons' population increase, their somatic growth and the formation of GABAergic synapses. In the presence of T3, GABAergic interneurons form longer axons and conspicuous axonal arborizations, with an increased number of putative synaptic boutons. Here we show that the increased GABAergic axonal growth is positively correlated with the proximity to non-GABAergic neurons (non-GABA). A differential innervation emerges from a T3-dependent decrease of axonal length in fields with low density of neuronal cell bodies, combined with an increased bouton formation in fields with high density of neuronal somata. T3 addition to deprived networks after the first 2 weeks of development did not rescue deficits in the GABAergic synaptic bouton distribution, or in the frequency and duration of spontaneous bursts. During the critical 2-week-period, GABAergic signaling is depolarizing as revealed by calcium imaging experiments. Interestingly, T3 enhanced the expression of the potassium-chloride cotransporter 2 (KCC2), and accelerated the developmental shift from depolarizing to hyperpolarizing GABAergic signaling in non-GABA. The T3-related increase of spontaneous network activity was remarkably reduced after blockade of either tropomyosin-receptor kinase B (trkB) or mammalian target of rapamycin (mTOR) pathways. T3-dependent increase in GABAergic neurons' soma size was mediated mainly by mTOR signaling. Conversely, the T3-dependent selective increase of GABAergic boutons near non-GABAergic cell bodies is mediated by trkB signaling only. Both trkB and mTOR signaling mediate T3-dependent reduction of the GABAergic axon extension. The circuitry context is relevant for the interaction between T3 and trkB signaling, but not for the interactions between T3 and mTOR signaling.
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Affiliation(s)
- Sören Westerholz
- Institute of Physiology, Otto-von-Guericke University Magdeburg, Germany
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48
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He JJ, Wu KF, Li S, Shu HF, Zhang CQ, Liu SY, Yang MH, Yin Q, Yang H. Expression of the interleukin 17 in cortical tubers of the tuberous sclerosis complex. J Neuroimmunol 2013; 262:85-91. [PMID: 23906968 DOI: 10.1016/j.jneuroim.2013.05.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2012] [Revised: 05/04/2013] [Accepted: 05/10/2013] [Indexed: 01/06/2023]
Abstract
The role of interleukin 17 (IL-17) to epilepsy-associated cortical tubers of tuberous sclerosis complex (TSC) is unknown. We investigated the expression patterns of the IL-17 and IL-17 receptor (IL-17R) in cortical tubers of TSC compared with normal control cortex (CTX). We found that IL-17 and IL-17R were clearly upregulated in cortical tubers at the protein levels. Immunostaining indicated that IL-17 was specifically distributed in the innate immunity cells (DNs, GCs, astrocytes, and microglia) and adaptive immunity cells (T-lymphocytes) as well as the endothelial cells of blood vessels. The overexpression and distribution patterns of IL-17 may be involved in the epileptogenicity of cortical tubers in TSC.
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Affiliation(s)
- Jiao-Jiang He
- Department of Neurosurgery, Xinqiao Hospital, Third Military Medical University, Chongqing 400037, China
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49
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Wu WE, Kirov II, Tal A, Babb JS, Milla S, Oved J, Weiner HL, Devinsky O, Gonen O. Brain MR spectroscopic abnormalities in "MRI-negative" tuberous sclerosis complex patients. Epilepsy Behav 2013; 27:319-25. [PMID: 23524469 PMCID: PMC3644963 DOI: 10.1016/j.yebeh.2013.02.018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/07/2013] [Revised: 02/13/2013] [Accepted: 02/16/2013] [Indexed: 11/25/2022]
Abstract
Since approximately 5-10% of the ~50,000 tuberous sclerosis complex (TSC) patients in the US are "MRI-negative," our goal was to test the hypothesis that they nevertheless exhibit metabolic abnormalities. To test this, we used proton MR spectroscopy to obtain and compare gray and white matter (GM and WM) levels of the neuronal marker, N-acetylaspartate (NAA), the glial marker, myo-inositol (mI), and its associated creatine (Cr), and choline (Cho) between two "MRI-negative" female TSC patients (ages 5 and 43 years) and their matched controls. The NAA, Cr, Cho and mI concentrations, 9.8, 6.3, 1.4, and 5.7 mM, in the pediatric control were similar to those of the patients, whereas the adult patient revealed a 17% WM NAA decrease and 16% WM Cho increase from their published means for healthy adults - both outside their respective 90% prediction intervals. These findings suggest that longer disease duration and/or TSC2 gene mutation may cause axonal dysfunction and demyelination.
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Affiliation(s)
- William E. Wu
- Department of Radiology, New York University School of Medicine, New York, NY 10016, USA
| | - Ivan I. Kirov
- Department of Radiology, New York University School of Medicine, New York, NY 10016, USA
| | - Assaf Tal
- Department of Radiology, New York University School of Medicine, New York, NY 10016, USA
| | - James S. Babb
- Department of Radiology, New York University School of Medicine, New York, NY 10016, USA
| | - Sarah Milla
- Department of Radiology, New York University School of Medicine, New York, NY 10016, USA
| | - Joseph Oved
- Department of Pediatrics, New York University School of Medicine, New York, NY 10016, USA,Department of Neurosurgery, New York University School of Medicine, New York, NY 10016, USA
| | - Howard L. Weiner
- Department of Pediatrics, New York University School of Medicine, New York, NY 10016, USA,Department of Neurosurgery, New York University School of Medicine, New York, NY 10016, USA
| | - Orrin Devinsky
- Department of Neurosurgery, New York University School of Medicine, New York, NY 10016, USA,Department of Neurology, New York University School of Medicine, New York, NY 10016, USA,Department of Psychiatry, New York University School of Medicine, New York, NY 10016, USA
| | - Oded Gonen
- Department of Radiology, New York University School of Medicine, New York, NY 10016, USA
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50
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Chalifoux JR, Perry N, Katz JS, Wiggins GC, Roth J, Miles D, Devinsky O, Weiner HL, Milla SS. The ability of high field strength 7-T magnetic resonance imaging to reveal previously uncharacterized brain lesions in patients with tuberous sclerosis complex. J Neurosurg Pediatr 2013; 11:268-73. [PMID: 23289918 DOI: 10.3171/2012.12.peds12338] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECT Tuberous sclerosis complex (TSC) brain pathology is characterized on MRI by cortical tubers, subependymal nodules, and subependymal giant cell astrocytomas. Seizures, the prominent feature of TSC, are frequently intractable to medical therapy and, in many patients, resection of tubers results in seizure control. However, in approximately 40% of patients, resection of tubers does not control seizures. This fact, as well as evidence from invasive electrophysiological recordings and experimental animal models, suggests that in patients with TSC, there may be extratuberal epileptogenic brain that does not display any apparent abnormality on conventional MRI. The authors hypothesized that high field strength MRI might uncover lesions not seen on conventional MRI in these patients. METHODS Institutional review board approval was obtained to scan 4 patients with TSC (ages 18-26 years) in a 7-T MR unit. Optimized 7-T sequences, including T1- and T2-weighted, FLAIR, SPACE FLAIR, T2*, and MPRAGE studies, were performed. Imaging studies were compared with identical sequences performed using a conventional 1.5-T MR scanner. RESULTS In all 4 patients, there was improved visualization of the findings demonstrated on conventional imaging. Importantly, new lesions were detected in all 4 patients, which were not well visualized with conventional MRI. Newly detected lesions included microtubers, radial glial signal abnormalities, subependymal nodules arising from the caudate nucleus, and caudate nucleus lesions. CONCLUSIONS High field strength MRI detects previously uncharacterized lesions in patients with TSC and allows better detection and delineation of subtle abnormalities. In addition, the data demonstrate a compelling relationship between intraventricular lesions and the caudate nucleus. These data support previous electrophysiological and animal-model findings that demonstrate neurological pathology beyond the conventionally detected lesions in TSC.
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Affiliation(s)
- Jason R Chalifoux
- Department of Neurosurgery, Division of Pediatric Neurosurgery, New York University Langone Medical Center, New York, NY 10016, USA
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