1
|
Kim EJ, Lee M, Yum MS. Specific inhibitor of Wnt/beta-catenin pathway can alter behavioral responses in young rats with malformed cortices. Behav Brain Res 2024; 460:114801. [PMID: 38070690 DOI: 10.1016/j.bbr.2023.114801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Revised: 11/24/2023] [Accepted: 12/04/2023] [Indexed: 12/24/2023]
Abstract
The Wnt/beta-catenin pathway plays a crucial role in regulating cellular processes and has been implicated in neural activity-dependent learning as well as anxiety. However, the role of this pathway in young children with abnormal cortical development is unknown. Cortical malformations at early development, behavioral abnormalities, and a susceptibility to seizures have been reported in rats prenatally exposed to methylazoxymethanol. In this study, we aimed to investigate whether we could improve the behavioral deficits in young rats with malformed cerebral cortices by modulation of the Wnt/beta-catenin pathway. We found a small molecule Wnt/beta-catenin inhibitor (CWP) that increased exploratory behavior in the open field test (P9, CWP 100 ug treatment, peripheral exploration, P = 0.011) and social behavior test (P12, CWP 250 ug treatment, distance traveled in center, P = 0.033) and decreased anxiety in fear conditioning. However, it did not reduce the susceptibility to seizures. After high dose (250 ug) CWP treatment at P12, phosphocreatine and glutathione (GSH) were decreased in the cortex at P15 (P = 0.021). These findings suggest that the role of Wnt/beta-catenin signaling in exploratory behavior and anxiety during early development warrants further investigation.
Collapse
Affiliation(s)
- Eun-Jin Kim
- Department of Pediatrics, University of Ulsan College of Medicine, Seoul 05505, South Korea; Asan Institute for Life Sciences, Asan Medical Center, Seoul 05505, South Korea
| | - Minyoung Lee
- Department of Pediatrics, University of Ulsan College of Medicine, Seoul 05505, South Korea; Asan Institute for Life Sciences, Asan Medical Center, Seoul 05505, South Korea
| | - Mi-Sun Yum
- Department of Pediatrics, University of Ulsan College of Medicine, Seoul 05505, South Korea; Department of Pediatrics, Asan Medical Center Children's Hospital, 88 Olympic-ro, Songpa-ku, Seoul 05505, South Korea.
| |
Collapse
|
2
|
Sciaccaluga M, Ruffolo G, Palma E, Costa C. Traditional and Innovative Anti-seizure Medications Targeting Key Physiopathological Mechanisms: Focus on Neurodevelopment and Neurodegeneration. Curr Neuropharmacol 2023; 21:1736-1754. [PMID: 37143270 PMCID: PMC10514539 DOI: 10.2174/1570159x21666230504160948] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2022] [Revised: 03/23/2023] [Accepted: 03/29/2023] [Indexed: 05/06/2023] Open
Abstract
Despite the wide range of compounds currently available to treat epilepsy, there is still no drug that directly tackles the physiopathological mechanisms underlying its development. Indeed, antiseizure medications attempt to prevent seizures but are inefficacious in counteracting or rescuing the physiopathological phenomena that underlie their onset and recurrence, and hence do not cure epilepsy. Classically, the altered excitation/inhibition balance is postulated as the mechanism underlying epileptogenesis and seizure generation. This oversimplification, however, does not account for deficits in homeostatic plasticity resulting from either insufficient or excessive compensatory mechanisms in response to a change in network activity. In this respect, both neurodevelopmental epilepsies and those associated with neurodegeneration may share common underlying mechanisms that still need to be fully elucidated. The understanding of these molecular mechanisms shed light on the identification of new classes of drugs able not only to suppress seizures, but also to present potential antiepileptogenic effects or "disease-modifying" properties.
Collapse
Affiliation(s)
- Miriam Sciaccaluga
- Section of Neurology, S.M. della Misericordia Hospital, Department of Medicine and Surgery, University of Perugia, Piazzale Gambuli 1, Perugia, 06129, Italy
| | - Gabriele Ruffolo
- Department of Physiology and Pharmacology, Istituto Pasteur—Fondazione Cenci Bolognetti, University of Rome, Sapienza, Rome, 00185, Italy
- IRCCS San Raffaele Roma, Rome, 00166, Italy
| | - Eleonora Palma
- Department of Physiology and Pharmacology, Istituto Pasteur—Fondazione Cenci Bolognetti, University of Rome, Sapienza, Rome, 00185, Italy
- IRCCS San Raffaele Roma, Rome, 00166, Italy
| | - Cinzia Costa
- Section of Neurology, S.M. della Misericordia Hospital, Department of Medicine and Surgery, University of Perugia, Piazzale Gambuli 1, Perugia, 06129, Italy
| |
Collapse
|
3
|
Lee WS, Baldassari S, Stephenson SEM, Lockhart PJ, Baulac S, Leventer RJ. Cortical Dysplasia and the mTOR Pathway: How the Study of Human Brain Tissue Has Led to Insights into Epileptogenesis. Int J Mol Sci 2022; 23:1344. [PMID: 35163267 PMCID: PMC8835853 DOI: 10.3390/ijms23031344] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 01/14/2022] [Accepted: 01/16/2022] [Indexed: 02/01/2023] Open
Abstract
Type II focal cortical dysplasia (FCD) is a neuropathological entity characterised by cortical dyslamination with the presence of dysmorphic neurons only (FCDIIA) or the presence of both dysmorphic neurons and balloon cells (FCDIIB). The year 2021 marks the 50th anniversary of the recognition of FCD as a cause of drug resistant epilepsy, and it is now the most common reason for epilepsy surgery. The causes of FCD remained unknown until relatively recently. The study of resected human FCD tissue using novel genomic technologies has led to remarkable advances in understanding the genetic basis of FCD. Mechanistic parallels have emerged between these non-neoplastic lesions and neoplastic disorders of cell growth and differentiation, especially through perturbations of the mammalian target of rapamycin (mTOR) signalling pathway. This narrative review presents the advances through which the aetiology of FCDII has been elucidated in chronological order, from recognition of an association between FCD and the mTOR pathway to the identification of somatic mosaicism within FCD tissue. We discuss the role of a two-hit mechanism, highlight current challenges and future directions in detecting somatic mosaicism in brain and discuss how knowledge of FCD may inform novel precision treatments of these focal epileptogenic malformations of human cortical development.
Collapse
Affiliation(s)
- Wei Shern Lee
- Bruce Lefroy Centre, Murdoch Children’s Research Institute, Parkville 3052, Australia; (W.S.L.); (S.E.M.S.); (P.J.L.)
- Department of Paediatrics, The University of Melbourne, Parkville 3052, Australia
| | - Sara Baldassari
- Institut du Cerveau-Paris Brain Institute-ICM, Sorbonne Université, Inserm, CNRS, Hôpital de la Pitié Salpêtrière, F-75013 Paris, France;
| | - Sarah E. M. Stephenson
- Bruce Lefroy Centre, Murdoch Children’s Research Institute, Parkville 3052, Australia; (W.S.L.); (S.E.M.S.); (P.J.L.)
- Department of Paediatrics, The University of Melbourne, Parkville 3052, Australia
| | - Paul J. Lockhart
- Bruce Lefroy Centre, Murdoch Children’s Research Institute, Parkville 3052, Australia; (W.S.L.); (S.E.M.S.); (P.J.L.)
- Department of Paediatrics, The University of Melbourne, Parkville 3052, Australia
| | - Stéphanie Baulac
- Institut du Cerveau-Paris Brain Institute-ICM, Sorbonne Université, Inserm, CNRS, Hôpital de la Pitié Salpêtrière, F-75013 Paris, France;
| | - Richard J. Leventer
- Department of Paediatrics, The University of Melbourne, Parkville 3052, Australia
- Murdoch Children’s Research Institute, Parkville 3052, Australia
- Department of Neurology, The Royal Children’s Hospital, Parkville 3052, Australia
| |
Collapse
|
4
|
Application of Thermodynamics and Protein–Protein Interaction Network Topology for Discovery of Potential New Treatments for Temporal Lobe Epilepsy. APPLIED SCIENCES-BASEL 2021. [DOI: 10.3390/app11178059] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
In this paper, we propose a bioinformatics-based method, which introduces thermodynamic measures and topological characteristics aimed to identify potential drug targets for pharmaco-resistant epileptic patients. We apply the Gibbs homology analysis to the protein–protein interaction network characteristic of temporal lobe epilepsy. With the identification of key proteins involved in the disease, particularly a number of ribosomal proteins, an assessment of their inhibitors is the next logical step. The results of our work offer a direction for future development of prospective therapeutic solutions for epilepsy patients, especially those who are not responding to the current standard of care.
Collapse
|
5
|
Karalis V, Bateup HS. Current Approaches and Future Directions for the Treatment of mTORopathies. Dev Neurosci 2021; 43:143-158. [PMID: 33910214 PMCID: PMC8440338 DOI: 10.1159/000515672] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Accepted: 02/13/2021] [Indexed: 11/19/2022] Open
Abstract
The mechanistic target of rapamycin (mTOR) is a kinase at the center of an evolutionarily conserved signaling pathway that orchestrates cell growth and metabolism. mTOR responds to an array of intra- and extracellular stimuli and in turn controls multiple cellular anabolic and catabolic processes. Aberrant mTOR activity is associated with numerous diseases, with particularly profound impact on the nervous system. mTOR is found in two protein complexes, mTOR complex 1 (mTORC1) and 2 (mTORC2), which are governed by different upstream regulators and have distinct cellular actions. Mutations in genes encoding for mTOR regulators result in a collection of neurodevelopmental disorders known as mTORopathies. While these disorders can affect multiple organs, neuropsychiatric conditions such as epilepsy, intellectual disability, and autism spectrum disorder have a major impact on quality of life. The neuropsychiatric aspects of mTORopathies have been particularly challenging to treat in a clinical setting. Current therapeutic approaches center on rapamycin and its analogs, drugs that are administered systemically to inhibit mTOR activity. While these drugs show some clinical efficacy, adverse side effects, incomplete suppression of mTOR targets, and lack of specificity for mTORC1 or mTORC2 may limit their utility. An increased understanding of the neurobiology of mTOR and the underlying molecular, cellular, and circuit mechanisms of mTOR-related disorders will facilitate the development of improved therapeutics. Animal models of mTORopathies have helped unravel the consequences of mTOR pathway mutations in specific brain cell types and developmental stages, revealing an array of disease-related phenotypes. In this review, we discuss current progress and potential future directions for the therapeutic treatment of mTORopathies with a focus on findings from genetic mouse models.
Collapse
Affiliation(s)
- Vasiliki Karalis
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, California, USA
| | - Helen S Bateup
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, California, USA
- Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, California, USA
- Chan Zuckerberg Biohub, San Francisco, California, USA
| |
Collapse
|
6
|
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: 29] [Impact Index Per Article: 9.7] [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.
Collapse
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
| |
Collapse
|
7
|
Affiliation(s)
- Peter B Crino
- Department of Neurology 12264University of Maryland School of Medicine
| |
Collapse
|
8
|
Kumari K, Sharma MC, Kakkar A, Malgulwar PB, Pathak P, Suri V, Sarkar C, Chandra SP, Faruq M. mTOR pathway activation in focal cortical dysplasia. Ann Diagn Pathol 2020; 46:151523. [PMID: 32325422 DOI: 10.1016/j.anndiagpath.2020.151523] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Revised: 02/21/2020] [Accepted: 03/24/2020] [Indexed: 01/05/2023]
Abstract
BACKGROUND Focal cortical dysplasia (FCD) is a localized cortical malformation and considerable morphological overlap exists between FCD IIB and neurological lesions associated with Tuberous sclerosis complex (TSC). Abnormal mTOR pathway secondary to somatic mTOR mutation and TSC gene mutation linked to PI3K/AKT/mTOR pathway have supported the hypothesis of common pathogenesis involved. Role of converging pathway, viz. Wnt/β-Catenin and mTOR is unknown in FCD. We aimed to analyse FCD IIB for TSC1/TSC2 mutations, immunoreactivity of hamartin, tuberin, mTOR and Wnt signalling cascades, and stem cell markers. MATERIALS AND METHODS Sixteen FCD IIB cases were retrieved along with 16 FCD IIA cases for comparison. Immunohistochemistry was performed for tuberin, hamartin, mTOR pathway markers, markers of stem cell phenotype, and Wnt pathway markers. Mutation analysis for TSC1 and TSC2 was performed by sequencing in 9 FCD cases. RESULTS All FCD cases showed preserved hamartin and tuberin immunoreactivity. Aberrant immunoreactivity of phospho-P70S6 kinase, S6 ribosomal, phospho-S6 ribosomal and Stat3 was noted in FCD IIB, with variable phospho-4E-BP1 (45%) and absent phospho-Stat3 expression. Immunoreactivity for phospho-P70S6 kinase (100%), S6 ribosomal protein (100%) and Stat3 (100%) was noted in FCD IIA, but not for phospho-S6 ribosomal, phospho-4E-BP1 and phospho-Stat3. c-Myc immunoreactivity was noted in all FCD cases. Nestin (81%) and Sox 2 (88%) stained balloon cells in FCD IIB (44%), while in FCD IIA cases were negative. All FCD cases were immunopositive for Wnt, but were negative for β-Catenin and cyclin-D1. TSC mutations were detected in two cases of FCD IIB. CONCLUSION Abnormal mTOR pathway activation exists in FCD IIB and IIA, however, shows differential immunoreactivity profile, indicating varying degrees of dysregulation. Labelling of neuronal stem cell markers in balloon cells suggests they are phenotypically immature. TSC1/2 mutation play role in the pathogenesis of FCD. Deep targeted sequencing is preferred diagnostic technique since conventional sanger sequencing often fails to detect low-allele frequency variants involved in mTOR/TSC pathway genes, commonly found in FCD.
Collapse
Affiliation(s)
- Kalpana Kumari
- Department of Pathology, All India Institute of Medical Sciences, New Delhi, India
| | - Mehar C Sharma
- Department of Pathology, All India Institute of Medical Sciences, New Delhi, India.
| | - Aanchal Kakkar
- Department of Pathology, All India Institute of Medical Sciences, New Delhi, India
| | - Prit B Malgulwar
- Department of Pathology, All India Institute of Medical Sciences, New Delhi, India
| | - Pankaj Pathak
- Department of Pathology, All India Institute of Medical Sciences, New Delhi, India
| | - Vaishali Suri
- Department of Pathology, All India Institute of Medical Sciences, New Delhi, India
| | - Chitra Sarkar
- Department of Pathology, All India Institute of Medical Sciences, New Delhi, India
| | - Sarat P Chandra
- Department of Neurosurgery, All India Institute of Medical Sciences, New Delhi, India
| | - Mohammed Faruq
- Institute of Genomics and Integrative Biology - Council of Scientific and Industrial Research, New Delhi, India
| |
Collapse
|
9
|
García-Rincón D, Díaz-Alonso J, Paraíso-Luna J, Ortega Z, Aguareles J, de Salas-Quiroga A, Jou C, de Prada I, Martínez-Cerdeño V, Aronica E, Guzmán M, Pérez-Jiménez MÁ, Galve-Roperh I. Contribution of Altered Endocannabinoid System to Overactive mTORC1 Signaling in Focal Cortical Dysplasia. Front Pharmacol 2019; 9:1508. [PMID: 30687088 PMCID: PMC6334222 DOI: 10.3389/fphar.2018.01508] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Accepted: 12/10/2018] [Indexed: 02/05/2023] Open
Abstract
Alterations of the PI3K/Akt/mammalian target of rapamycin complex 1 (mTORC1) signaling pathway are causally involved in a subset of malformations of cortical development (MCDs) ranging from focal cortical dysplasia (FCD) to hemimegalencephaly and megalencephaly. These MCDs represent a frequent cause of refractory pediatric epilepsy. The endocannabinoid system -especially cannabinoid CB1 receptor- exerts a neurodevelopmental regulatory role at least in part via activation of mTORC1 signaling. Therefore, we sought to characterize the possible contribution of endocannabinoid system signaling to FCD. Confocal microscopy characterization of the CB1 receptor expression and mTORC1 activation was conducted in FCD Type II resection samples. FCD samples were subjected to single nucleotide polymorphism screening for endocannabinoid system elements, as well as CB1 receptor gene sequencing. Cannabinoid CB1 receptor levels were increased in FCD with overactive mTORC1 signaling. CB1 receptors were enriched in phospho-S6-positive cells including balloon cells (BCs) that co-express aberrant markers of undifferentiated cells and dysplastic neurons. Pharmacological regulation of CB1 receptors and the mTORC1 pathway was performed in fresh FCD-derived organotypic cultures. HU-210-evoked activation of CB1 receptors was unable to further activate mTORC1 signaling, whereas CB1 receptor blockade with rimonabant attenuated mTORC1 overactivation. Alterations of the endocannabinoid system may thus contribute to FCD pathological features, and blockade of cannabinoid signaling might be a new therapeutic intervention in FCD.
Collapse
Affiliation(s)
- Daniel García-Rincón
- Instituto Ramón y Cajal de Investigación Sanitaria, Department of Biochemistry and Molecular Biology and Instituto Universitario de Investigación Neuroquímica, Complutense University, Madrid, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas, Madrid, Spain
| | - Javier Díaz-Alonso
- Instituto Ramón y Cajal de Investigación Sanitaria, Department of Biochemistry and Molecular Biology and Instituto Universitario de Investigación Neuroquímica, Complutense University, Madrid, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas, Madrid, Spain
| | - Juan Paraíso-Luna
- Instituto Ramón y Cajal de Investigación Sanitaria, Department of Biochemistry and Molecular Biology and Instituto Universitario de Investigación Neuroquímica, Complutense University, Madrid, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas, Madrid, Spain
| | - Zaira Ortega
- Instituto Ramón y Cajal de Investigación Sanitaria, Department of Biochemistry and Molecular Biology and Instituto Universitario de Investigación Neuroquímica, Complutense University, Madrid, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas, Madrid, Spain
| | - José Aguareles
- Instituto Ramón y Cajal de Investigación Sanitaria, Department of Biochemistry and Molecular Biology and Instituto Universitario de Investigación Neuroquímica, Complutense University, Madrid, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas, Madrid, Spain
| | - Adán de Salas-Quiroga
- Instituto Ramón y Cajal de Investigación Sanitaria, Department of Biochemistry and Molecular Biology and Instituto Universitario de Investigación Neuroquímica, Complutense University, Madrid, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas, Madrid, Spain
| | - Cristina Jou
- Departamento de Anatomía Patológica, Hospital Sant Joan de Déu, Barcelona, Spain
| | | | - Verónica Martínez-Cerdeño
- Institute for Pediatric Regenerative Medicine, Shriners Hospital for Children of Northern California and Department of Pathology and Laboratory Medicine, School of Medicine, University of California, Davis, Sacramento, CA, United States
| | - Eleonora Aronica
- Amsterdam UMC, Department of (Neuro)Pathology, Amsterdam Neuroscience, University of Amsterdam, Amsterdam, Netherlands.,Stichting Epilepsie Instellingen Nederland, Heemstede, Netherlands
| | - Manuel Guzmán
- Instituto Ramón y Cajal de Investigación Sanitaria, Department of Biochemistry and Molecular Biology and Instituto Universitario de Investigación Neuroquímica, Complutense University, Madrid, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas, Madrid, Spain
| | | | - Ismael Galve-Roperh
- Instituto Ramón y Cajal de Investigación Sanitaria, Department of Biochemistry and Molecular Biology and Instituto Universitario de Investigación Neuroquímica, Complutense University, Madrid, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas, Madrid, Spain
| |
Collapse
|
10
|
Arena A, Zimmer TS, van Scheppingen J, Korotkov A, Anink JJ, Mühlebner A, Jansen FE, van Hecke W, Spliet WG, van Rijen PC, Vezzani A, Baayen JC, Idema S, Iyer AM, Perluigi M, Mills JD, van Vliet EA, Aronica E. Oxidative stress and inflammation in a spectrum of epileptogenic cortical malformations: molecular insights into their interdependence. Brain Pathol 2018; 29:351-365. [PMID: 30303592 DOI: 10.1111/bpa.12661] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Revised: 09/14/2018] [Accepted: 10/01/2018] [Indexed: 12/20/2022] Open
Abstract
Oxidative stress (OS) occurs in brains of patients with epilepsy and coincides with brain inflammation, and both phenomena contribute to seizure generation in animal models. We investigated whether expression of OS and brain inflammation markers co-occurred also in resected brain tissue of patients with epileptogenic cortical malformations: hemimegalencephaly (HME), focal cortical dysplasia (FCD) and cortical tubers in tuberous sclerosis complex (TSC). Moreover, we studied molecular mechanisms linking OS and inflammation in an in vitro model of neuronal function. Untangling interdependency and underlying molecular mechanisms might pose new therapeutic strategies for treating patients with drug-resistant epilepsy of different etiologies. Immunohistochemistry was performed for specific OS markers xCT and iNOS and brain inflammation markers TLR4, COX-2 and NF-κB in cortical tissue derived from patients with HME, FCD IIa, IIb and TSC. Additionally, we studied gene expression of these markers using the human neuronal cell line SH-SY5Y in which OS was induced using H2 O2 . OS markers were higher in dysmorphic neurons and balloon/giant cells in cortex of patients with FCD IIb or TSC. Expression of OS markers was positively correlated to expression of brain inflammation markers. In vitro, 100 µM, but not 50 µM, of H2 O2 increased expression of TLR4, IL-1β and COX-2. We found that NF-κB signaling was activated only upon stimulation with 100 µM H2 O2 leading to upregulation of TLR4 signaling and IL-1β. The NF-κB inhibitor TPCA-1 completely reversed this effect. Our results show that OS positively correlates with neuroinflammation and is particularly evident in brain tissue of patients with FCD IIb and TSC. In vitro, NF-κB is involved in the switch to an inflammatory state after OS. We propose that the extent of OS can predict the neuroinflammatory state of the brain. Additionally, antioxidant treatments may prevent the switch to inflammation in neurons thus targeting multiple epileptogenic processes at once.
Collapse
Affiliation(s)
- Andrea Arena
- Department of (Neuro-)Pathology, Amsterdam UMC, University of Amsterdam, Amsterdam Neuroscience, Meibergdreef 9, Amsterdam, the Netherlands.,Department of Biochemical Sciences, Sapienza University of Rome, Rome, Italy
| | - Till S Zimmer
- Department of (Neuro-)Pathology, Amsterdam UMC, University of Amsterdam, Amsterdam Neuroscience, Meibergdreef 9, Amsterdam, the Netherlands
| | - Jackelien van Scheppingen
- Department of (Neuro-)Pathology, Amsterdam UMC, University of Amsterdam, Amsterdam Neuroscience, Meibergdreef 9, Amsterdam, the Netherlands
| | - Anatoly Korotkov
- Department of (Neuro-)Pathology, Amsterdam UMC, University of Amsterdam, Amsterdam Neuroscience, Meibergdreef 9, Amsterdam, the Netherlands
| | - Jasper J Anink
- Department of (Neuro-)Pathology, Amsterdam UMC, University of Amsterdam, Amsterdam Neuroscience, Meibergdreef 9, Amsterdam, the Netherlands
| | - Angelika Mühlebner
- Department of (Neuro-)Pathology, Amsterdam UMC, University of Amsterdam, Amsterdam Neuroscience, Meibergdreef 9, Amsterdam, the Netherlands
| | - Floor E Jansen
- Department of Pediatric Neurology, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Wim van Hecke
- Department of Pathology, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Wim G Spliet
- Department of Pathology, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Peter C van Rijen
- Department of Neurosurgery, Rudolf Magnus Institute for Neuroscience, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Annamaria Vezzani
- Department of Neuroscience, IRCCS-Istituto di Ricerche Farmacologiche "Mario Negri", Milan, Italy
| | - Johannes C Baayen
- Department of Neurosurgery, Amsterdam Neuroscience, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam, the Netherlands
| | - Sander Idema
- Department of Neurosurgery, Amsterdam Neuroscience, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam, the Netherlands
| | - Anand M Iyer
- Department of (Neuro-)Pathology, Amsterdam UMC, University of Amsterdam, Amsterdam Neuroscience, Meibergdreef 9, Amsterdam, the Netherlands
| | - Marzia Perluigi
- Department of Biochemical Sciences, Sapienza University of Rome, Rome, Italy
| | - James D Mills
- Department of (Neuro-)Pathology, Amsterdam UMC, University of Amsterdam, Amsterdam Neuroscience, Meibergdreef 9, Amsterdam, the Netherlands
| | - Erwin A van Vliet
- Department of (Neuro-)Pathology, Amsterdam UMC, University of Amsterdam, Amsterdam Neuroscience, Meibergdreef 9, Amsterdam, the Netherlands.,Swammerdam Institute for Life Sciences, Center for Neuroscience, University of Amsterdam, Amsterdam, the Netherlands
| | - Eleonora Aronica
- Department of (Neuro-)Pathology, Amsterdam UMC, University of Amsterdam, Amsterdam Neuroscience, Meibergdreef 9, Amsterdam, the Netherlands.,Stichting Epilepsie Instellingen Nederland (SEIN), the Netherlands
| |
Collapse
|
11
|
Griffin NG, Cronin KD, Walley NM, Hulette CM, Grant GA, Mikati MA, LaBreche HG, Rehder CW, Allen AS, Crino PB, Heinzen EL. Somatic uniparental disomy of Chromosome 16p in hemimegalencephaly. Cold Spring Harb Mol Case Stud 2017; 3:mcs.a001735. [PMID: 28864461 PMCID: PMC5593155 DOI: 10.1101/mcs.a001735] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2017] [Accepted: 04/24/2017] [Indexed: 02/05/2023] Open
Abstract
Hemimegalencephaly (HME) is a heterogeneous cortical malformation characterized by enlargement of one cerebral hemisphere. Somatic variants in mammalian target of rapamycin (mTOR) regulatory genes have been implicated in some HME cases; however, ∼70% have no identified genetic etiology. Here, we screened two HME patients to identify disease-causing somatic variants. DNA from leukocytes, buccal swabs, and surgically resected brain tissue from two HME patients were screened for somatic variants using genome-wide genotyping arrays or sequencing of the protein-coding regions of the genome. Functional studies were performed to evaluate the molecular consequences of candidate disease-causing variants. Both HME patients evaluated were found to have likely disease-causing variants in DNA extracted from brain tissue but not in buccal swab or leukocyte DNA, consistent with a somatic mutational mechanism. In the first case, a previously identified disease-causing somatic single nucleotide in MTOR was identified. In the second case, we detected an overrepresentation of the alleles inherited from the mother on Chromosome 16 in brain tissue DNA only, indicative of somatic uniparental disomy (UPD) of the p-arm of Chromosome 16. Using methylation analyses, an imprinted locus on 16p spanning ZNF597 was identified, which results in increased expression of ZNF597 mRNA and protein in the brain tissue of the second case. Enhanced mTOR signaling was observed in tissue specimens from both patients. We speculate that overexpression of maternally expressed ZNF597 led to aberrant hemispheric development in the patient with somatic UPD of Chromosome 16p possibly through modulation of mTOR signaling.
Collapse
Affiliation(s)
- Nicole G Griffin
- Institute for Genomic Medicine, Columbia University, New York, New York 10032, USA
| | - Kenneth D Cronin
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, North Carolina 27710, USA
| | - Nicole M Walley
- Division of Medical Genetics, Department of Pediatrics, Duke University School of Medicine, Durham, North Carolina 27710, USA
| | - Christine M Hulette
- Department of Pathology, Duke University School of Medicine, Durham, North Carolina 27710, USA
| | - Gerald A Grant
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, California 94305, USA
| | - Mohamad A Mikati
- Division of Pediatric Neurology, Duke University Medical Center, Durham, North Carolina 27710, USA.,Department of Neurobiology, Duke University, Durham, North Carolina 27708, USA
| | | | | | - Andrew S Allen
- Department of Biostatistics and Bioinformatics, Duke University, Durham, North Carolina 27710, USA
| | - Peter B Crino
- Department of Neurology, University of Maryland, School of Medicine, Baltimore, Maryland 21201, USA
| | - Erin L Heinzen
- Institute for Genomic Medicine, Columbia University, New York, New York 10032, USA.,Department of Pathology and Cell Biology, Columbia University, New York, New York 10032, USA
| |
Collapse
|
12
|
Iffland PH, Crino PB. Focal Cortical Dysplasia: Gene Mutations, Cell Signaling, and Therapeutic Implications. ANNUAL REVIEW OF PATHOLOGY-MECHANISMS OF DISEASE 2017; 12:547-571. [PMID: 28135561 DOI: 10.1146/annurev-pathol-052016-100138] [Citation(s) in RCA: 84] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Focal cortical dysplasias (FCDs) are malformations of cortical development (MCDs) that are highly associated with medication-resistant epilepsy and are the most common cause of neocortical epilepsy in children. FCDs are a heterogeneous group of developmental disorders caused by germline or somatic mutations that occur in genes regulating the PI3K/Akt/mTOR pathway-a key pathway in neuronal growth and migration. Accordingly, FCDs are characterized by abnormal cortical lamination, cell morphology (e.g., cytomegaly), and cellular polarity. In some FCD subtypes, balloon cells express proteins typically seen in neuroglial progenitor cells. Because recurrent intractable seizures are a common feature of FCDs, epileptogenic electrophysiological properties are also observed in addition to local inflammation. Here, we will summarize the current literature regarding FCDs, addressing the current classification system, histopathology, molecular genetics, electrophysiology, and transcriptome and cell signaling changes.
Collapse
Affiliation(s)
- Philip H Iffland
- Shriners Hospitals Pediatric Research Center, Lewis Katz School of Medicine, Temple University, Philadelphia, Pennsylvania 19140;
| | - Peter B Crino
- Department of Neurology, University of Maryland School of Medicine, Baltimore, Maryland 21201;
| |
Collapse
|
13
|
Abstract
INTRODUCTION Dishevelled, Egl-10 and Pleckstrin (DEP) domain-containing protein 5 (DEPDC5) is a protein subunit of the GTPase-activating proteins towards Rags 1 (GATOR1) complex. GATOR1 is a recently identified modulator of mechanistic target of rapamycin (mTOR) activity. mTOR is a key regulator of cell proliferation and metabolism; disruption of the mTOR pathway is implicated in focal epilepsy, both acquired and genetic. Tuberous sclerosis is the prototypic mTOR genetic syndrome with epilepsy, however GATOR1 gene mutations have recently been shown to cause lesional and non-lesional focal epilepsy. Areas covered: This review summarizes the mTOR pathway, including regulators and downstream effectors, emphasizing recent developments in the understanding of the complex role of the GATOR1 complex. We review the epilepsy types associated with mTOR overactivity, including tuberous sclerosis, polyhydramnios megalencephaly symptomatic epilepsy, cortical dysplasia, non-lesional focal epilepsy and post-traumatic epilepsy. Currently available mTOR inhibitors are discussed, primarily rapamycin analogs and ATP competitive mTOR inhibitors. Expert opinion: DEPDC5 is an attractive therapeutic target in focal epilepsy, as effects of DEPDC5 agonists would likely be anti-epileptogenic and more selective than currently available mTOR inhibitors. Therapeutic effects might be synergistic with certain existing dietary therapies, including the ketogenic diet.
Collapse
Affiliation(s)
- Kenneth A Myers
- a Epilepsy Research Centre, Department of Medicine , The University of Melbourne, Austin Health , Heidelberg , Victoria , Australia.,b Department of Paediatrics , Royal Children's Hospital, The University of Melbourne , Flemington , Victoria , Australia
| | - Ingrid E Scheffer
- a Epilepsy Research Centre, Department of Medicine , The University of Melbourne, Austin Health , Heidelberg , Victoria , Australia.,b Department of Paediatrics , Royal Children's Hospital, The University of Melbourne , Flemington , Victoria , Australia.,c The Florey Institute of Neuroscience and Mental Health , Heidelberg , Victoria , Australia
| |
Collapse
|
14
|
Somatic Mutations in TSC1 and TSC2 Cause Focal Cortical Dysplasia. Am J Hum Genet 2017; 100:454-472. [PMID: 28215400 DOI: 10.1016/j.ajhg.2017.01.030] [Citation(s) in RCA: 141] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Accepted: 01/23/2017] [Indexed: 12/18/2022] Open
Abstract
Focal cortical dysplasia (FCD) is a major cause of the sporadic form of intractable focal epilepsies that require surgical treatment. It has recently been reported that brain somatic mutations in MTOR account for 15%-25% of FCD type II (FCDII), characterized by cortical dyslamination and dysmorphic neurons. However, the genetic etiologies of FCDII-affected individuals who lack the MTOR mutation remain unclear. Here, we performed deep hybrid capture and amplicon sequencing (read depth of 100×-20,012×) of five important mTOR pathway genes-PIK3CA, PIK3R2, AKT3, TSC1, and TSC2-by using paired brain and saliva samples from 40 FCDII individuals negative for MTOR mutations. We found that 5 of 40 individuals (12.5%) had brain somatic mutations in TSC1 (c.64C>T [p.Arg22Trp] and c.610C>T [p.Arg204Cys]) and TSC2 (c.4639G>A [p.Val1547Ile]), and these results were reproducible on two different sequencing platforms. All identified mutations induced hyperactivation of the mTOR pathway by disrupting the formation or function of the TSC1-TSC2 complex. Furthermore, in utero CRISPR-Cas9-mediated genome editing of Tsc1 or Tsc2 induced the development of spontaneous behavioral seizures, as well as cytomegalic neurons and cortical dyslamination. These results show that brain somatic mutations in TSC1 and TSC2 cause FCD and that in utero application of the CRISPR-Cas9 system is useful for generating neurodevelopmental disease models of somatic mutations in the brain.
Collapse
|
15
|
Biever A, Valjent E, Puighermanal E. Ribosomal Protein S6 Phosphorylation in the Nervous System: From Regulation to Function. Front Mol Neurosci 2015; 8:75. [PMID: 26733799 PMCID: PMC4679984 DOI: 10.3389/fnmol.2015.00075] [Citation(s) in RCA: 152] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Accepted: 11/23/2015] [Indexed: 01/31/2023] Open
Abstract
Since the discovery of the phosphorylation of the 40S ribosomal protein S6 (rpS6) about four decades ago, much effort has been made to uncover the molecular mechanisms underlying the regulation of this post-translational modification. In the field of neuroscience, rpS6 phosphorylation is commonly used as a readout of the mammalian target of rapamycin complex 1 signaling activation or as a marker for neuronal activity. Nevertheless, its biological role in neurons still remains puzzling. Here we review the pharmacological and physiological stimuli regulating this modification in the nervous system as well as the pathways that transduce these signals into rpS6 phosphorylation. Altered rpS6 phosphorylation observed in various genetic and pathophysiological mouse models is also discussed. Finally, we examine the current state of knowledge on the physiological role of this post-translational modification and highlight the questions that remain to be addressed.
Collapse
Affiliation(s)
- Anne Biever
- Centre National de la Recherche Scientifique, UMR5203, Institut de Génomique FonctionnelleMontpellier, France; Institut National de la Santé et de la Recherche Médicale, U1191Montpellier, France; Université de Montpellier, UMR-5203Montpellier, France
| | - Emmanuel Valjent
- Centre National de la Recherche Scientifique, UMR5203, Institut de Génomique FonctionnelleMontpellier, France; Institut National de la Santé et de la Recherche Médicale, U1191Montpellier, France; Université de Montpellier, UMR-5203Montpellier, France
| | - Emma Puighermanal
- Centre National de la Recherche Scientifique, UMR5203, Institut de Génomique FonctionnelleMontpellier, France; Institut National de la Santé et de la Recherche Médicale, U1191Montpellier, France; Université de Montpellier, UMR-5203Montpellier, France
| |
Collapse
|
16
|
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.
Collapse
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
| |
Collapse
|
17
|
van Vuurden DG, Aronica E, Hulleman E, Wedekind LE, Biesmans D, Malekzadeh A, Bugiani M, Geerts D, Noske DP, Vandertop WP, Kaspers GJL, Cloos J, Würdinger T, van der Stoop PPM. Pre-B-cell leukemia homeobox interacting protein 1 is overexpressed in astrocytoma and promotes tumor cell growth and migration. Neuro Oncol 2015; 16:946-59. [PMID: 24470547 DOI: 10.1093/neuonc/not308] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
BACKGROUND Glial brain tumors cause considerable mortality and morbidity in children and adults. Innovative targets for therapy are needed to improve survival and reduce long-term sequelae. The aim of this study was to find a candidate tumor-promoting protein, abundantly expressed in tumor cells but not in normal brain tissues, as a potential target for therapy. METHODS In silico proteomics and genomics, immunohistochemistry, and immunofluorescence microscopy validation were performed. RNA interference was used to ascertain the functional role of the overexpressed candidate target protein. RESULTS In silico proteomics and genomics revealed pre-B-cell leukemia homeobox (PBX) interacting protein 1 (PBXIP1) overexpression in adult and childhood high-grade glioma and ependymoma compared with normal brain. PBXIP1 is a PBX-family interacting microtubule-binding protein with a putative role in migration and proliferation of cancer cells. Immunohistochemical studies in glial tumors validated PBXIP1 expression in astrocytoma and ependymoma but not in oligodendroglioma. RNAi-mediated PBXIP1-knockdown in glioblastoma cell lines strongly reduced proliferation and migration and induced morphological changes, indicating that PBXIP1 knockdown decreases glioma cell viability and motility through rearrangements of the actin cytoskeleton. Furthermore, expression of PBXIP1 was observed in radial glia and astrocytic progenitor cells in human fetal tissues, suggesting that PBXIP1 is an astroglial progenitor cell marker during human embryonic development. CONCLUSION PBXIP1 is a novel protein overexpressed in astrocytoma and ependymoma, involved in tumor cell proliferation and migration, that warrants further exploration as a novel therapeutic target in these tumors.
Collapse
|
18
|
Affiliation(s)
- Peter B Crino
- Shriners Hospitals Paediatric Research Centre, Department of Neurology, Temple University School of Medicine, Philadelphia, USA
| |
Collapse
|
19
|
Chrastina J, Novak Z, Brazdil M, Hermanova M. Glioblastoma Multiforme in a Patient with Isolated Hemimegalencephaly. J Neurol Surg Rep 2015; 76:e160-3. [PMID: 26251796 PMCID: PMC4520982 DOI: 10.1055/s-0035-1554929] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Accepted: 03/12/2015] [Indexed: 12/11/2022] Open
Abstract
We present an exceptional case of a patient with hemimegalencephaly and secondary intractable epilepsy treated with vagus nerve stimulation (VNS) and subsequent glioblastoma development in the hemimegalencephalic hemisphere 6 years after surgery. VNS (at age 18 years) led to a 60% reduction of intractable seizures. However, symptoms of intracranial hypertension suddenly occurred 6 years after surgery. A computed tomography scan revealed a brain tumor in the hemimegalencephalic hemisphere. Pathologic examination confirmed glioblastoma multiforme. The genetic background of hemimegalencephaly is discussed here, with attention paid to the available data about the malignant transformation of malformations of cortical development (MCDs). The case points to the need for adequate clinical and radiologic follow-up care for patients with MCDs including hemimegalencephaly.
Collapse
Affiliation(s)
- Jan Chrastina
- Department of Neurosurgery MF MU, Faculty Hospital St. Ann's, Brno, Czech Republic
| | - Zdenek Novak
- Department of Neurosurgery MF MU, Faculty Hospital St. Ann's, Brno, Czech Republic
| | - Milan Brazdil
- Department of Neurosurgery MF MU, Faculty Hospital St. Ann's, Brno, Czech Republic
| | - Marketa Hermanova
- Department of Pathological Anatomy MF MU, Faculty Hospital St. Ann's, Brno, Czech Republic
| |
Collapse
|
20
|
Abstract
Focal cortical dysplasias are common malformations of cerebral cortical development and are highly associated with medically intractable epilepsy. They have been classified into neuropathological subtypes (type Ia, Ib, IIa, IIb, and III) based on the severity of cytoarchitectural disruption--tangential or radial dispersion, or loss of laminar structure--and the presence of unique cells types such as cytomegalic neurons or balloon cells. Most focal cortical dysplasias can be identified on neuroimaging and many require resective epilepsy surgery to cure refractory seizures. The pathogenesis of focal cortical dysplasias remains to be defined, although there is recent evidence to suggest that focal cortical dysplasias arise from de novo somatic mutations occurring during brain development. Some focal cortical dysplasia subtypes show a link to the mammalian target of rapamycin signaling cascade; this has now extended to other cortical malformations, including hemimegalencephaly.
Collapse
Affiliation(s)
- Peter B Crino
- Department of Neurology, Shriners Hospital Pediatric Research Center and Temple University, Philadelphia, Pennsylvania
| |
Collapse
|
21
|
Sarnat HB, Flores-Sarnat L. Infantile tauopathies: Hemimegalencephaly; tuberous sclerosis complex; focal cortical dysplasia 2; ganglioglioma. Brain Dev 2015; 37:553-62. [PMID: 25451314 DOI: 10.1016/j.braindev.2014.08.010] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/14/2014] [Revised: 07/31/2014] [Accepted: 08/04/2014] [Indexed: 11/16/2022]
Abstract
Tau is a normal microtubule-associated protein; mutations to phosphorylated or acetylated forms are neurotoxic. In many dementias of adult life tauopathies cause neuronal degeneration. Four developmental disorders of the fetal and infant brain are presented, each of which exhibits up-regulation of tau. Microtubules are cytoskeletal structures that provide the strands of mitotic spindles and specify cellular polarity, growth, lineage, differentiation, migration and axonal transport of molecules. Phosphorylated tau is abnormal in immature as in mature neurons. Several malformations are demonstrated in which upregulated tau may be important in pathogenesis. All produce highly epileptogenic cortical foci. The prototype infantile tauopathy is (1) hemimegalencephaly (HME); normal tau is degraded by a mutant AKT3 or AKT1 gene as the aetiology of focal somatic mosaicism in the periventricular neuroepithelium. HME may be isolated or associated with neurocutaneous syndromes, particularly epidermal naevus syndromes, also due to somatic mutations. Other tauopathies of early life include: (2) tuberous sclerosis complex; (3) focal cortical dysplasia type 2b (FCD2b); and (4) ganglioglioma, a tumor with dysplastic neurons and neoplastic glial cells. Pathological tau in these infantile cases alters cellular growth and architecture, synaptic function and tissue organization, but does not cause neuronal loss. All infantile tauopathies are defined neuropathologically as a tetrad of (1) dysmorphic and megalocytic neurons; (2) activation of the mTOR signaling pathway; (3) post-zygotic somatic mosaicism; and (4) upregulation of phosphorylated tau. HME and FCD2b may be the same disorder with different timing of the somatic mutation in the mitotic cycles of the neuroepithelium. HME and FCD2b may be the same disorder with different timing of the somatic mutation in the mitotic cycles of the neuroepithelium. Tauopathies must be considered in infantile neurological disease and no longer restricted to adult dementias. The mTOR inhibitor everolimus, already demonstrated to be effective in TSC, also may be a potential treatment in other infantile tauopathies.
Collapse
Affiliation(s)
- Harvey B Sarnat
- Department of Paediatrics, University of Calgary Faculty of Medicine and Alberta Children's Hospital Research Foundation, Calgary, Alberta, Canada; Department of Pathology (Neuropathology), University of Calgary Faculty of Medicine and Alberta Children's Hospital Research Foundation, Calgary, Alberta, Canada; Department of Clinical Neurosciences, University of Calgary Faculty of Medicine and Alberta Children's Hospital Research Foundation, Calgary, Alberta, Canada.
| | - Laura Flores-Sarnat
- Department of Paediatrics, University of Calgary Faculty of Medicine and Alberta Children's Hospital Research Foundation, Calgary, Alberta, Canada; Department of Clinical Neurosciences, University of Calgary Faculty of Medicine and Alberta Children's Hospital Research Foundation, Calgary, Alberta, Canada
| |
Collapse
|
22
|
Crino PB. mTOR signaling in epilepsy: insights from malformations of cortical development. Cold Spring Harb Perspect Med 2015; 5:5/4/a022442. [PMID: 25833943 DOI: 10.1101/cshperspect.a022442] [Citation(s) in RCA: 103] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Over the past decade enhanced activation of the mammalian target of rapamycin (mTOR)-signaling cascade has been identified in focal malformations of cortical development (MCD) subtypes, which have been collectively referred to as "mTORopathies." Mutations in mTOR regulatory genes (e.g., TSC1, TSC2, AKT3, DEPDC5) have been associated with several focal MCD highly associated with epilepsy such as tuberous sclerosis complex (TSC), hemimegalencephaly (HME; brain malformation associated with dramatic enlargement of one brain hemisphere), and cortical dysplasia. mTOR plays important roles in the regulation of cell division, growth, and survival, and, thus, aberrant activation of the cascade during cortical development can cause dramatic alterations in cell size, cortical lamination, and axon and dendrite outgrowth often observed in focal MCD. Although it is widely believed that structural alterations induced by hyperactivated mTOR signaling are critical for epileptogenesis, newer evidence suggests that mTOR activation on its own may enhance neuronal excitability. Clinical trials with mTOR inhibitors have shown efficacy in the treatment of seizures associated with focal MCD.
Collapse
Affiliation(s)
- Peter B Crino
- Shriners Hospital Pediatric Research Center and Department of Neurology, Temple University, Philadelphia, Pennsylvania 19140
| |
Collapse
|
23
|
Nguyen LH, Brewster AL, Clark ME, Regnier-Golanov A, Sunnen CN, Patil VV, D'Arcangelo G, Anderson AE. mTOR inhibition suppresses established epilepsy in a mouse model of cortical dysplasia. Epilepsia 2015; 56:636-46. [PMID: 25752454 DOI: 10.1111/epi.12946] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/21/2015] [Indexed: 12/21/2022]
Abstract
OBJECTIVE Hyperactivation of the mechanistic target of rapamycin (mTOR; also known as mammalian target of rapamycin) pathway has been demonstrated in human cortical dysplasia (CD) as well as in animal models of epilepsy. Although inhibition of mTOR signaling early in epileptogenesis suppressed epileptiform activity in the neuron subset-specific Pten knockout (NS-Pten KO) mouse model of CD, the effects of mTOR inhibition after epilepsy is fully established were not previously examined in this model. Here, we investigated whether mTOR inhibition suppresses epileptiform activity and other neuropathological correlates in adult NS-Pten KO mice with severe and well-established epilepsy. METHODS The progression of epileptiform activity, mTOR pathway dysregulation, and associated neuropathology with age in NS-Pten KO mice were evaluated using video-electroencephalography (EEG) recordings, Western blotting, and immunohistochemistry. A cohort of NS-Pten KO mice was treated with the mTOR inhibitor rapamycin (10 mg/kg i.p., 5 days/week) starting at postnatal week 9 and video-EEG monitored for epileptiform activity. Western blotting and immunohistochemistry were performed to evaluate the effects of rapamycin on the associated pathology. RESULTS Epileptiform activity worsened with age in NS-Pten KO mice, with parallel increases in the extent of hippocampal mTOR complex 1 and 2 (mTORC1 and mTORC2, respectively) dysregulation and progressive astrogliosis and microgliosis. Rapamycin treatment suppressed epileptiform activity, improved baseline EEG activity, and increased survival in severely epileptic NS-Pten KO mice. At the molecular level, rapamycin treatment was associated with a reduction in both mTORC1 and mTORC2 signaling and decreased astrogliosis and microgliosis. SIGNIFICANCE These findings reveal a wide temporal window for successful therapeutic intervention with rapamycin in the NS-Pten KO mouse model, and they support mTOR inhibition as a candidate therapy for established, late-stage epilepsy associated with CD and genetic dysregulation of the mTOR pathway.
Collapse
Affiliation(s)
- Lena H Nguyen
- Department of Neuroscience, Baylor College of Medicine, Houston, Texas, U.S.A; The Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, Texas, U.S.A; The Gordon and Mary Cain Pediatric Neurology Research Foundation Laboratories, Texas Children's Hospital, Houston, Texas, U.S.A
| | | | | | | | | | | | | | | |
Collapse
|
24
|
Jansen LA, Mirzaa GM, Ishak GE, O'Roak BJ, Hiatt JB, Roden WH, Gunter SA, Christian SL, Collins S, Adams C, Rivière JB, St-Onge J, Ojemann JG, Shendure J, Hevner RF, Dobyns WB. PI3K/AKT pathway mutations cause a spectrum of brain malformations from megalencephaly to focal cortical dysplasia. Brain 2015; 138:1613-28. [PMID: 25722288 DOI: 10.1093/brain/awv045] [Citation(s) in RCA: 246] [Impact Index Per Article: 27.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Accepted: 12/22/2014] [Indexed: 11/15/2022] Open
Abstract
Malformations of cortical development containing dysplastic neuronal and glial elements, including hemimegalencephaly and focal cortical dysplasia, are common causes of intractable paediatric epilepsy. In this study we performed multiplex targeted sequencing of 10 genes in the PI3K/AKT pathway on brain tissue from 33 children who underwent surgical resection of dysplastic cortex for the treatment of intractable epilepsy. Sequencing results were correlated with clinical, imaging, pathological and immunohistological phenotypes. We identified mosaic activating mutations in PIK3CA and AKT3 in this cohort, including cancer-associated hotspot PIK3CA mutations in dysplastic megalencephaly, hemimegalencephaly, and focal cortical dysplasia type IIa. In addition, a germline PTEN mutation was identified in a male with hemimegalencephaly but no peripheral manifestations of the PTEN hamartoma tumour syndrome. A spectrum of clinical, imaging and pathological abnormalities was found in this cohort. While patients with more severe brain imaging abnormalities and systemic manifestations were more likely to have detected mutations, routine histopathological studies did not predict mutation status. In addition, elevated levels of phosphorylated S6 ribosomal protein were identified in both neurons and astrocytes of all hemimegalencephaly and focal cortical dysplasia type II specimens, regardless of the presence or absence of detected PI3K/AKT pathway mutations. In contrast, expression patterns of the T308 and S473 phosphorylated forms of AKT and in vitro AKT kinase activities discriminated between mutation-positive dysplasia cortex, mutation-negative dysplasia cortex, and non-dysplasia epilepsy cortex. Our findings identify PI3K/AKT pathway mutations as an important cause of epileptogenic brain malformations and establish megalencephaly, hemimegalencephaly, and focal cortical dysplasia as part of a single pathogenic spectrum.
Collapse
Affiliation(s)
- Laura A Jansen
- 1 University of Virginia, Neurology, Charlottesville, VA, USA 2 Seattle Children's Research Institute, Centre for Integrative Brain Research, Seattle, WA, USA
| | - Ghayda M Mirzaa
- 2 Seattle Children's Research Institute, Centre for Integrative Brain Research, Seattle, WA, USA 3 University of Washington, Paediatrics, Seattle, WA, USA
| | - Gisele E Ishak
- 4 Seattle Children's Hospital, Radiology, Seattle, WA, USA
| | - Brian J O'Roak
- 5 University of Washington, Genome Sciences, Seattle, WA, USA 6 Oregon Health and Science University, Molecular and Medical Genetics, Portland, OR, USA
| | - Joseph B Hiatt
- 5 University of Washington, Genome Sciences, Seattle, WA, USA
| | - William H Roden
- 2 Seattle Children's Research Institute, Centre for Integrative Brain Research, Seattle, WA, USA
| | - Sonya A Gunter
- 1 University of Virginia, Neurology, Charlottesville, VA, USA
| | - Susan L Christian
- 2 Seattle Children's Research Institute, Centre for Integrative Brain Research, Seattle, WA, USA
| | - Sarah Collins
- 2 Seattle Children's Research Institute, Centre for Integrative Brain Research, Seattle, WA, USA
| | - Carissa Adams
- 2 Seattle Children's Research Institute, Centre for Integrative Brain Research, Seattle, WA, USA
| | - Jean-Baptiste Rivière
- 2 Seattle Children's Research Institute, Centre for Integrative Brain Research, Seattle, WA, USA 7 Université de Bourgogne, Equipe Génétique des Anomalies du Développement, Dijon, France
| | - Judith St-Onge
- 2 Seattle Children's Research Institute, Centre for Integrative Brain Research, Seattle, WA, USA 7 Université de Bourgogne, Equipe Génétique des Anomalies du Développement, Dijon, France
| | | | - Jay Shendure
- 5 University of Washington, Genome Sciences, Seattle, WA, USA
| | - Robert F Hevner
- 2 Seattle Children's Research Institute, Centre for Integrative Brain Research, Seattle, WA, USA 8 University of Washington, Neurosurgery, Seattle, WA, USA
| | - William B Dobyns
- 2 Seattle Children's Research Institute, Centre for Integrative Brain Research, Seattle, WA, USA 3 University of Washington, Paediatrics, Seattle, WA, USA
| |
Collapse
|
25
|
Lozovaya N, Gataullina S, Tsintsadze T, Tsintsadze V, Pallesi-Pocachard E, Minlebaev M, Goriounova NA, Buhler E, Watrin F, Shityakov S, Becker AJ, Bordey A, Milh M, Scavarda D, Bulteau C, Dorfmuller G, Delalande O, Represa A, Cardoso C, Dulac O, Ben-Ari Y, Burnashev N. Selective suppression of excessive GluN2C expression rescues early epilepsy in a tuberous sclerosis murine model. Nat Commun 2014; 5:4563. [PMID: 25081057 PMCID: PMC4143949 DOI: 10.1038/ncomms5563] [Citation(s) in RCA: 83] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2014] [Accepted: 06/30/2014] [Indexed: 01/06/2023] Open
Abstract
Tuberous sclerosis complex (TSC), caused by dominant mutations in either
TSC1 or
TSC2 tumour
suppressor genes is characterized by the presence of brain malformations, the
cortical tubers that are thought to contribute to the generation of
pharmacoresistant epilepsy. Here we report that tuberless heterozygote
Tsc1+/− mice show
functional upregulation of cortical GluN2C-containing N-methyl-D-aspartate receptors (NMDARs) in an
mTOR-dependent manner and exhibit recurrent, unprovoked seizures during early
postnatal life (<P19). Seizures are generated intracortically in the granular
layer of the neocortex. Slow kinetics of aberrant GluN2C-mediated currents in spiny stellate cells promotes
excessive temporal integration of persistent NMDAR-mediated recurrent excitation and
seizure generation. Accordingly, specific GluN2C/D antagonists block seizures in Tsc1+/− mice in vivo
and in vitro. Likewise, GluN2C expression is upregulated in TSC human surgical
resections, and a GluN2C/D
antagonist reduces paroxysmal hyperexcitability. Thus, GluN2C receptor constitutes a promising
molecular target to treat epilepsy in TSC patients. Tuberous sclerosis complex (TSC) is a rare genetic condition
characterized by epileptic seizures that start in infancy. Here, the authors show that
these seizures are modulated by GluN2C-containing NMDA receptors in the cortex of a
mouse model of TSC, and that suppressing their activity attenuates seizures.
Collapse
Affiliation(s)
- N Lozovaya
- 1] INSERM U901, INMED, Parc Scientifique et Technologique de Luminy 163, route de Luminy-BP 13, 13273 Marseille Cedex 09, France [2] UMR901, Aix-Marseille University, 58 Boulevard Charles Livon, 13284 Marseille, France [3] INSERM U1129; University Paris Descartes, CEA, Gif sur Yvette, 149 Rue de Sèvres, 75015 Paris, France [4]
| | - S Gataullina
- 1] INSERM U901, INMED, Parc Scientifique et Technologique de Luminy 163, route de Luminy-BP 13, 13273 Marseille Cedex 09, France [2] UMR901, Aix-Marseille University, 58 Boulevard Charles Livon, 13284 Marseille, France [3] INSERM U1129; University Paris Descartes, CEA, Gif sur Yvette, 149 Rue de Sèvres, 75015 Paris, France [4]
| | - T Tsintsadze
- 1] INSERM U901, INMED, Parc Scientifique et Technologique de Luminy 163, route de Luminy-BP 13, 13273 Marseille Cedex 09, France [2] UMR901, Aix-Marseille University, 58 Boulevard Charles Livon, 13284 Marseille, France [3]
| | - V Tsintsadze
- 1] INSERM U901, INMED, Parc Scientifique et Technologique de Luminy 163, route de Luminy-BP 13, 13273 Marseille Cedex 09, France [2] UMR901, Aix-Marseille University, 58 Boulevard Charles Livon, 13284 Marseille, France
| | - E Pallesi-Pocachard
- 1] INSERM U901, INMED, Parc Scientifique et Technologique de Luminy 163, route de Luminy-BP 13, 13273 Marseille Cedex 09, France [2] UMR901, Aix-Marseille University, 58 Boulevard Charles Livon, 13284 Marseille, France
| | - M Minlebaev
- 1] INSERM U901, INMED, Parc Scientifique et Technologique de Luminy 163, route de Luminy-BP 13, 13273 Marseille Cedex 09, France [2] UMR901, Aix-Marseille University, 58 Boulevard Charles Livon, 13284 Marseille, France [3] Laboratory of Neurobiology, Kazan Federal University, Kremlevskaya street 18, 420000 Kazan, Russia
| | - N A Goriounova
- 1] INSERM U901, INMED, Parc Scientifique et Technologique de Luminy 163, route de Luminy-BP 13, 13273 Marseille Cedex 09, France [2] UMR901, Aix-Marseille University, 58 Boulevard Charles Livon, 13284 Marseille, France
| | - E Buhler
- 1] INSERM U901, INMED, Parc Scientifique et Technologique de Luminy 163, route de Luminy-BP 13, 13273 Marseille Cedex 09, France [2] UMR901, Aix-Marseille University, 58 Boulevard Charles Livon, 13284 Marseille, France
| | - F Watrin
- 1] INSERM U901, INMED, Parc Scientifique et Technologique de Luminy 163, route de Luminy-BP 13, 13273 Marseille Cedex 09, France [2] UMR901, Aix-Marseille University, 58 Boulevard Charles Livon, 13284 Marseille, France
| | - S Shityakov
- Department of Anaesthesia and Critical Care, University of Würzburg, Josef-Schneider-Street 2, 97080 Würzburg, Germany
| | - A J Becker
- Department of Neuropathology, University of Bonn Medical Center, Sigmund Freud Street 25, D-53105 Bonn, Germany
| | - A Bordey
- Neurosurgery, and Cellular and Molecular Physiology Departments, Yale University School of Medicine, PO Box 208082, New Haven, Connecticut 06520-8082, USA
| | - M Milh
- APHM, Department of Pediatric Neurosurgery and Neurology, CHU Timone, 264 Rue Saint-Pierre, 13385 Marseille Cedex 5, France
| | - D Scavarda
- APHM, Department of Pediatric Neurosurgery and Neurology, CHU Timone, 264 Rue Saint-Pierre, 13385 Marseille Cedex 5, France
| | - C Bulteau
- 1] INSERM U1129; University Paris Descartes, CEA, Gif sur Yvette, 149 Rue de Sèvres, 75015 Paris, France [2] Department of Pediatric Neurosurgery, Foundation Rothschild, 29 Rue Manin, 75019 Paris, France
| | - G Dorfmuller
- 1] INSERM U1129; University Paris Descartes, CEA, Gif sur Yvette, 149 Rue de Sèvres, 75015 Paris, France [2] Department of Pediatric Neurosurgery, Foundation Rothschild, 29 Rue Manin, 75019 Paris, France
| | - O Delalande
- Department of Pediatric Neurosurgery, Foundation Rothschild, 29 Rue Manin, 75019 Paris, France
| | - A Represa
- 1] INSERM U901, INMED, Parc Scientifique et Technologique de Luminy 163, route de Luminy-BP 13, 13273 Marseille Cedex 09, France [2] UMR901, Aix-Marseille University, 58 Boulevard Charles Livon, 13284 Marseille, France
| | - C Cardoso
- 1] INSERM U901, INMED, Parc Scientifique et Technologique de Luminy 163, route de Luminy-BP 13, 13273 Marseille Cedex 09, France [2] UMR901, Aix-Marseille University, 58 Boulevard Charles Livon, 13284 Marseille, France
| | - O Dulac
- 1] INSERM U1129; University Paris Descartes, CEA, Gif sur Yvette, 149 Rue de Sèvres, 75015 Paris, France [2] Department of Pediatric Neurosurgery, Foundation Rothschild, 29 Rue Manin, 75019 Paris, France [3] APHP, Necker Hospital, 149 Rue de Sèvres, 75015 Paris, France
| | - Y Ben-Ari
- 1] INSERM U901, INMED, Parc Scientifique et Technologique de Luminy 163, route de Luminy-BP 13, 13273 Marseille Cedex 09, France [2] UMR901, Aix-Marseille University, 58 Boulevard Charles Livon, 13284 Marseille, France
| | - N Burnashev
- 1] INSERM U901, INMED, Parc Scientifique et Technologique de Luminy 163, route de Luminy-BP 13, 13273 Marseille Cedex 09, France [2] UMR901, Aix-Marseille University, 58 Boulevard Charles Livon, 13284 Marseille, France
| |
Collapse
|
26
|
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.
Collapse
Affiliation(s)
- Isaac Marin-Valencia
- Department of Neurology and Neurotherapeutics, and Pediatrics, University of Texas Southwestern Medical Center, Dallas, Texas, U.S.A
| | | | | |
Collapse
|
27
|
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.
Collapse
Affiliation(s)
- Eleonora Aronica
- Department of (Neuro)Pathology, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105, AZ, Amsterdam, The Netherlands,
| | | |
Collapse
|
28
|
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
| |
Collapse
|
29
|
Leventer RJ, Jansen FE, Mandelstam SA, Ho A, Mohamed I, Sarnat HB, Kato M, Fukasawa T, Saitsu H, Matsumoto N, Itoh M, Kalnins RM, Chow CW, Harvey AS, Jackson GD, Crino PB, Berkovic SF, Scheffer IE. Is focal cortical dysplasia sporadic? Family evidence for genetic susceptibility. Epilepsia 2014; 55:e22-6. [DOI: 10.1111/epi.12533] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/02/2013] [Indexed: 02/01/2023]
Affiliation(s)
- Richard J. Leventer
- Department of Neurology; Royal Children's Hospital; Melbourne Victoria Australia
- Murdoch Childrens Research Institute; Melbourne Victoria Australia
- Department of Pediatrics; University of Melbourne; Melbourne Victoria Australia
| | - Floor E. Jansen
- Department of Pediatric Neurology; Rudolf Magnus Institute of Neurosciences; University Medical Center Utrecht; Utrecht The Netherlands
- Epilepsy Research Centre; University of Melbourne; Austin Health; Melbourne Victoria Australia
| | - Simone A. Mandelstam
- The Florey Institute of Neuroscience and Mental Health; Melbourne Victoria Australia
- Department of Radiology; University of Melbourne; Melbourne Victoria Australia
| | - Alice Ho
- Departments of Pediatrics and Clinical Neurosciences; Alberta Children's Hospital; University of Calgary; Calgary Alberta Canada
| | - Ismail Mohamed
- Department of Pediatrics; IWK Health Center; Dalhousie University; Halifax Nova Scotia Canada
| | - Harvey B. Sarnat
- Department of Pediatrics, Pathology, (Neuropathology) and Clinical Neurosciences; University of Calgary Faculty of Medicine; Alberta Children's Hospital; Calgary Alberta Canada
| | - Mitsuhiro Kato
- Department of Pediatrics; Yamagata University Faculty of Medicine; Yamagata Japan
| | | | - Hirotomo Saitsu
- Department of Human Genetics; Yokohama City University Graduate School of Medicine; Yokohama Japan
| | - Naomichi Matsumoto
- Department of Human Genetics; Yokohama City University Graduate School of Medicine; Yokohama Japan
| | - Masayuki Itoh
- Department of Mental Retardation and Birth Defect Research; National Institute of Neuroscience; National Center of Neurology and Psychiatry; Tokyo Japan
| | - Renate M. Kalnins
- Department of Anatomical Pathology; Austin Hospital; Melbourne Victoria Australia
- Department of Pathology; University of Melbourne; Melbourne Victoria Australia
| | - Chung W. Chow
- Department of Pediatrics; University of Melbourne; Melbourne Victoria Australia
- Department of Anatomical Pathology; Royal Children's Hospital; Melbourne Victoria Australia
| | - A. Simon Harvey
- Department of Neurology; Royal Children's Hospital; Melbourne Victoria Australia
- Murdoch Childrens Research Institute; Melbourne Victoria Australia
- Department of Pediatrics; University of Melbourne; Melbourne Victoria Australia
| | - Graeme D. Jackson
- Epilepsy Research Centre; University of Melbourne; Austin Health; Melbourne Victoria Australia
- Department of Radiology; University of Melbourne; Melbourne Victoria Australia
| | - Peter B. Crino
- Shriners Hospitals Pediatric Research Center; Temple University; Philadelphia Pennsylvania U.S.A
| | - Samuel F. Berkovic
- Epilepsy Research Centre; University of Melbourne; Austin Health; Melbourne Victoria Australia
| | - Ingrid E. Scheffer
- Department of Neurology; Royal Children's Hospital; Melbourne Victoria Australia
- Department of Pediatrics; University of Melbourne; Melbourne Victoria Australia
- Epilepsy Research Centre; University of Melbourne; Austin Health; Melbourne Victoria Australia
- Department of Radiology; University of Melbourne; Melbourne Victoria Australia
| |
Collapse
|
30
|
Prabowo AS, Iyer AM, Veersema TJ, Anink JJ, Schouten-van Meeteren AYN, Spliet WGM, van Rijen PC, Ferrier CH, Capper D, Thom M, Aronica E. BRAF V600E mutation is associated with mTOR signaling activation in glioneuronal tumors. Brain Pathol 2013; 24:52-66. [PMID: 23941441 DOI: 10.1111/bpa.12081] [Citation(s) in RCA: 113] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2013] [Accepted: 07/25/2013] [Indexed: 02/06/2023] Open
Abstract
BRAF V600E mutations have been recently reported in glioneuronal tumors (GNTs). To evaluate the expression of the BRAF V600E mutated protein and its association with activation of the mammalian target of rapamycin (mTOR) pathway, immunophenotype and clinical characteristics in GNTs, we investigated a cohort of 174 GNTs. The presence of BRAF V600E mutations was detected by direct DNA sequencing and BRAF V600E immunohistochemical detection. Expression of BRAF-mutated protein was detected in 38/93 (40.8%) gangliogliomas (GGs), 2/4 (50%) desmoplastic infantile gangliogliomas (DIGs) and 23/77 (29.8%) dysembryoplastic neuroepithelial tumors (DNTs) by immunohistochemistry. In both GGs and DNTs, the presence of BRAF V600E mutation was significantly associated with the expression of CD34, phosphorylated ribosomal S6 protein (pS6; marker of mTOR pathway activation) in dysplastic neurons and synaptophysin (P < 0.05). In GGs, the presence of lymphocytic cuffs was more frequent in BRAF-mutated cases (31 vs. 15.8%; P=0.001). The expression of both BRAF V600E and pS6 was associated with a worse postoperative seizure outcome in GNT (P < 0.001). Immunohistochemical detection of BRAF V600E-mutated protein may be valuable in the diagnostic evaluation of these glioneuronal lesions and the observed association with mTOR activation may aid in the development of targeted treatment involving specific pathogenic pathways.
Collapse
Affiliation(s)
- Avanita S Prabowo
- Department of (Neuro)Pathology, University of Amsterdam, Amsterdam, The Netherlands
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
31
|
Lim KC, Crino PB. Focal malformations of cortical development: new vistas for molecular pathogenesis. Neuroscience 2013; 252:262-76. [PMID: 23892008 DOI: 10.1016/j.neuroscience.2013.07.037] [Citation(s) in RCA: 70] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2013] [Revised: 07/10/2013] [Accepted: 07/10/2013] [Indexed: 12/16/2022]
Abstract
Focal malformations of cortical development (FMCD) are highly associated with several neurological disorders including intractable epilepsy and neurocognitive disabilities. Over the past decade, several FMCD subtypes have been linked to hyperactivation of the mammalian target of rapamycin (mTOR) signaling cascade. In view of the roles that mTOR plays in cell proliferation, size, motility, and stem cell phenotype, many of the features of FMCD such as cytomegaly, disorganized lamination, and expression of stem cell markers can be explained by enhanced mTOR signaling. FMCD result from several distinct and fascinating molecular mechanisms including biallelic gene inactivation, somatic mutation, and potentially, viral infection. These mechanisms have been directly linked to mTOR activation. Perhaps most compelling, pharmacological inhibition of mTOR has been implemented successfully in clinical trials for select FMCD and provides a new vista for treatment.
Collapse
Affiliation(s)
- K-C Lim
- Department of Neurology, University of Pennsylvania Medical Center, Philadelphia, PA, United States
| | | |
Collapse
|
32
|
Munakata M, Watanabe M, Otsuki T, Itoh M, Uematsu M, Saito Y, Honda R, Kure S. Increased Ki-67 immunoreactivity in the white matter in hemimegalencephaly. Neurosci Lett 2013; 548:244-8. [PMID: 23721782 DOI: 10.1016/j.neulet.2013.05.033] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2013] [Revised: 05/15/2013] [Accepted: 05/16/2013] [Indexed: 01/01/2023]
Abstract
Hemimegalencephaly (HMG) is a developmental brain disorder characterized by an enlarged unilateral hemisphere with cortical malformation comprising abnormal hypertrophic cells. To address the proliferative status of HMG, Ki-67 immunoreactivity was investigated in HMG specimens obtained during epilepsy surgery. Nine HMG tissues were stained with a Ki-67 antibody and Ki-67 labeling index in the malformed cortex, and the underlying white matter was measured separately and compared with tissues from focal cortical dysplasias and normal brains from autopsy. In HMG tissues, Ki-67-positive cells were scattered in both the gray and white matter, with a significantly higher Ki-67 labeling index in the white matter compared with gray matter. No dysmorphic neuron or balloon cell was stained for Ki-67. As Ki-67 immunoreactivity overlapped with that of ionized calcium-binding adaptor protein-1, Ki-67-positive cells were identified as microglia. In HMG, microglia were activated and entered into a proliferative status with higher distribution in the white matter, implying an ongoing neuroinflammatory process involving the white matter.
Collapse
Affiliation(s)
- Mitsutoshi Munakata
- Department of Pediatrics, Tohoku University School of Medicine, Sendai, Japan.
| | | | | | | | | | | | | | | |
Collapse
|
33
|
Abstract
Structural abnormalities of the brain are increasingly recognized in patients that suffer from pharmacoresistant focal epilepsies by applying high-resolution imaging techniques. In many of these patients, epilepsy surgery results in control of seizures. Neuropathologically, a broad spectrum of malformations of cortical development (MCD) is observed in respective surgical brain samples. These samples provide a unique basis to further understand underlying pathomechanisms by molecular approaches and develop improved diagnostics and entirely new therapeutic perspectives. Here we provide a comprehensive description of neuropathological findings, available classification systems as well as molecular mechanisms of MCDs. We emphasize the recently published ILEA classification system for focal cortical dysplasias (FCDs), which are now histopathologically distinguished as types I to III. However, this revised classification system represents a major challenge for molecular neuropathologists, as the underlying pathomechanisms in virtually all FCD entities will need to be specified in detail. The fact that only recently, the mammalian target of rapamycin (mTOR)-antagonist Everolimus has been introduced as a treatment of epilepsies in the context of tuberous sclerosis-associated brain lesions is a striking example of a successful translational "bedside to bench and back" approach. Hopefully, the exciting clinico-pathological developments in the field of MCDs will in short term foster further therapeutic breakthroughs for the frequently associated medically refractory epilepsies.
Collapse
Affiliation(s)
- Eleonora Aronica
- Department of (Neuro)Pathology, Academic Medical Center, University of Amsterdam, Amsterdam
| | | | | |
Collapse
|
34
|
Pavlidis E, Cantalupo G, Boria S, Cossu G, Pisani F. Hemimegalencephalic variant of epidermal nevus syndrome: case report and literature review. Eur J Paediatr Neurol 2012; 16:332-42. [PMID: 22200538 DOI: 10.1016/j.ejpn.2011.12.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/14/2011] [Revised: 12/02/2011] [Accepted: 12/03/2011] [Indexed: 11/18/2022]
Abstract
The epidermal nevus syndrome (ENS) is an uncommon neurocutaneous disorder in which epidermal nevi are found in association with congenital abnormalities of the brain, eye, and/or skeleton. The association of epidermal nevi and neurologic abnormalities was comprehensively described by Schimmelpenning in 1957. Pavone et al. (1991) identified a homogeneous variant of ENS with hemimegalencephaly, gyral malformation, mental retardation, seizures and facial hemihypertrophy. A 13-year-old boy with the neurologic variant of ENS with hemimegalencephaly, facial asymmetry, febrile seizures and mental retardation is reported. Additionally, we performed a literature review using the search terms "epidermal nevus syndrome" and "hemimegalencephaly", including secondary sources of data such as reference lists of articles reviewed. We found 57 previously reported cases with the hemimegalencephalic variant of epidermal nevus syndrome, in which the most frequent associated features are severe epilepsy, in about half of cases with neonatal onset, mental retardation/developmental delay, ocular/visual involvement, and facial abnormalities.
Collapse
Affiliation(s)
- Elena Pavlidis
- Child Neuropsychiatry Unit, University of Parma, Via Gramsci 14, 43126 Parma, Italy
| | | | | | | | | |
Collapse
|
35
|
Crino PB. mTOR: A pathogenic signaling pathway in developmental brain malformations. Trends Mol Med 2011; 17:734-42. [DOI: 10.1016/j.molmed.2011.07.008] [Citation(s) in RCA: 193] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2011] [Revised: 07/19/2011] [Accepted: 07/21/2011] [Indexed: 11/16/2022]
|
36
|
Wong M. Mammalian target of rapamycin (mTOR) activation in focal cortical dysplasia and related focal cortical malformations. Exp Neurol 2011; 244:22-6. [PMID: 22015915 DOI: 10.1016/j.expneurol.2011.10.002] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2011] [Accepted: 10/03/2011] [Indexed: 01/20/2023]
Abstract
Focal cortical dysplasia (FCD) and other localized malformations of cortical development represent common causes of intractable pediatric epilepsy. Insights into the cellular and molecular pathogenesis of focal cortical malformations may reveal information about associated mechanisms of epileptogenesis and suggest new therapies for seizures caused by these developmental lesions. In animal models and human studies of FCD and the related disease of Tuberous Sclerosis Complex (TSC), the mammalian target of rapamycin (mTOR) pathway has been implicated in mediating cellular and molecular changes leading to the formation of the cortical malformations and the expression of epilepsy. The use of mTOR inhibitors may represent a rational therapeutic strategy for treating or even preventing epilepsy due to FCD and TSC.
Collapse
Affiliation(s)
- Michael Wong
- Department of Neurology and the Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, MO 63110, USA.
| |
Collapse
|
37
|
Uematsu M, Haginoya K, Togashi N, Hino-Fukuyo N, Nakayama T, Kikuchi A, Abe Y, Wakusawa K, Matsumoto Y, Kakisaka Y, Kobayashi T, Hirose M, Yokoyama H, Iinuma K, Iwasaki M, Nakasato N, Kaneta T, Akasaka M, Kamei A, Tsuchiya S. Unique discrepancy between cerebral blood flow and glucose metabolism in hemimegalencephaly. Epilepsy Res 2010; 92:201-8. [DOI: 10.1016/j.eplepsyres.2010.09.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2009] [Revised: 09/13/2010] [Accepted: 09/15/2010] [Indexed: 11/27/2022]
|
38
|
Immunohistochemical characterization of the out-of frame splice variants GFAP Δ164/Δexon 6 in focal lesions associated with chronic epilepsy. Epilepsy Res 2010; 90:99-109. [DOI: 10.1016/j.eplepsyres.2010.03.014] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2009] [Revised: 03/24/2010] [Accepted: 03/31/2010] [Indexed: 11/19/2022]
|
39
|
Abstract
Tuberous sclerosis complex (TSC) is an autosomal dominant disorder that results from mutations in the TSC1 or TSC2 genes and is associated with hamartoma formation in multiple organ systems. The neurological manifestations of TSC are particularly challenging and include infantile spasms, intractable epilepsy, cognitive disabilities, and autism. Progress over the past 15 years has demonstrated that the TSC1 or TSC2 encoded proteins modulate cell function via the mTOR signaling cascade and serve as keystones in regulating cell growth and proliferation. The mTOR pathway provides an intersection for an intricate network of protein cascades that respond to cellular nutrition, energy levels, and growth-factor stimulation. In the brain, TSC1 and TSC2 have been implicated in cell body size, dendritic arborization, axonal outgrowth and targeting, neuronal migration, cortical lamination, and spine formation. Antagonism of the mTOR pathway with rapamycin and related compounds may provide new therapeutic options for TSC patients.
Collapse
Affiliation(s)
- Ksenia A Orlova
- Departments of Neurology and Neuroscience, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA
| | | |
Collapse
|
40
|
Baybis M, Aronica E, Nathanson KL, Crino PB. Deletion of 15q11.2-15q13.1 in isolated human hemimegalencephaly. Acta Neuropathol 2009; 118:821-3. [PMID: 19851776 DOI: 10.1007/s00401-009-0603-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2009] [Revised: 10/12/2009] [Accepted: 10/13/2009] [Indexed: 11/30/2022]
|
41
|
Boer K, Lucassen PJ, Spliet WGM, Vreugdenhil E, van Rijen PC, Troost D, Jansen FE, Aronica E. Doublecortin-like (DCL) expression in focal cortical dysplasia and cortical tubers. Epilepsia 2009; 50:2629-37. [DOI: 10.1111/j.1528-1167.2009.02191.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
42
|
Nonoda Y, Saito Y, Itoh M, Nakagawa E, Sugai K, Takahashi A, Otsuki T, Saito Y, Arima K, Mizuguchi M, Goto YI, Sasaki M. Activation of microglia/macrophages expressing phosphorylated S6 ribosomal protein in a case of hemimegalencephaly with progressive calcification and atrophy. J Neurol Sci 2009; 287:52-9. [DOI: 10.1016/j.jns.2009.09.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2009] [Revised: 08/27/2009] [Accepted: 09/10/2009] [Indexed: 01/01/2023]
|
43
|
Abstract
Focal malformations of cortical development are highly associated with intractable epilepsy in children and adults. Most patients with focal cortical malformations and epilepsy will require epilepsy surgery. Recent studies have provided new insights into the developmental pathogenesis of cortical malformations specifically relating to alterations in cell signaling though the mammalian target of rapamycin (mTOR) pathway. Focal cortical dysplasias, hemimegalencephaly, and tubers in tuberous sclerosis complex all exhibit evidence for hyperactive mTOR signaling, suggesting that these disorders form a spectrum of malformations or "TORopathies" characterized by disorganized cortical lamination, cytomegaly, and intractable seizures. Alterations in mTOR activity in focal brain malformations provide a potential pathogenic pathway to investigate for gene mutations and to exploit for animal models. Most importantly, however, if select focal cortical malformations result from enhanced mTOR signaling, new therapeutic antiepileptic compounds, such as rapamycin, can be designed and tested that specifically target mTOR signaling.
Collapse
Affiliation(s)
- Peter B Crino
- Department of Neurology, PENN Epilepsy Center, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.
| |
Collapse
|
44
|
Boer K, Troost D, Timmermans W, van Rijen PC, Spliet WGM, Aronica E. Pi3K-mTOR signaling and AMOG expression in epilepsy-associated glioneuronal tumors. Brain Pathol 2009; 20:234-44. [PMID: 19371356 DOI: 10.1111/j.1750-3639.2009.00268.x] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Gangliogliomas (GGs) and dysembryoplastic neuroepithelial tumors (DNTs) represent the most frequent type of neoplasms in pediatric medically intractable epilepsy. Several data suggest a pathogenetic relationship between GGs and other glioneuronal malformations of cortical development (MCDs), including activation of the Pi3K-mTOR signaling pathway. To further reveal these pathogenetic similarities, we investigated immunocytochemically the expression of phosphorylated (p)-PDK1, p-AKT, p-mTOR, p-4E-BP1, p-eIF4G, p-p70S6K and p-S6, the effector proteins ERM (ezrin/radixin/moesin) and the pathway regulator AMOG (adhesion molecule on glia) in both GGs and DNTs. Components of the Pi3K-mTOR signaling pathway were observed in a higher percentage of neuronal cells in GGs compared with control cortex. In DNTs, the expression of these components was low and comparable with the expression in control samples. Strong immunoreactivity for ERM was observed in GGs, but not in DNTs. Additionally, AMOG was strongly expressed within GGs (but not in DNTs) in CD34-positive precursor cells. These findings support the previously suggested pathogenic relationship between GG and MCDs concerning activation of the Pi3K-mTOR signaling pathway and suggest a different pathogenetic origin for DNTs. The strong expression of AMOG within the precursor cells of GG may represent an additional marker for the diagnostic evaluation of these glioneuronal lesions.
Collapse
Affiliation(s)
- Karin Boer
- Department of (Neuro)Pathology, Academic Medical Center, University of Amsterdam, The Netherlands
| | | | | | | | | | | |
Collapse
|
45
|
Abstract
A 5-year-old girl with a history of hypomelanosis of Ito and intractable epilepsy was evaluated for possible resective surgery. Magnetic resonance imaging showed an enlarged right hemisphere, whereas electrographic seizures were arising from the right hemisphere or had a generalized onset. The patient was believed to be a good candidate for hemispherectomy, but the family was hesitant and started a modified Atkins diet. Her seizure control has improved, but she continues to have weekly seizures. Hypomelanosis of Ito is a well-known cause of hemimegalencephaly and is often associated with intractable epilepsy and hemiparesis. Hemispherectomy can often be an effective treatment in intractable cases.
Collapse
Affiliation(s)
- Kevin Chapman
- Division of Child Neurology, Barrow Neurological Institute and St Joseph's Hospital & Medical Center, Phoenix, AZ 85013, USA.
| | | |
Collapse
|
46
|
Boer K, Troost D, Timmermans W, Gorter JA, Spliet WGM, Nellist M, Jansen F, Aronica E. Cellular localization of metabotropic glutamate receptors in cortical tubers and subependymal giant cell tumors of tuberous sclerosis complex. Neuroscience 2008; 156:203-15. [PMID: 18706978 DOI: 10.1016/j.neuroscience.2008.06.073] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2008] [Revised: 06/22/2008] [Accepted: 06/26/2008] [Indexed: 11/27/2022]
Abstract
Tuberous sclerosis complex (TSC) is an autosomal dominant disorder associated with cortical malformations (cortical tubers) and the development of glial tumors (subependymal giant-cell tumors, SGCTs). Expression of metabotropic glutamate receptor (mGluR) subtypes is developmentally regulated and several studies suggest an involvement of mGluR-mediated glutamate signaling in the regulation of proliferation and survival of neural stem-progenitor cells, as well as in the control of tumor growth. In the present study, we have investigated the expression and cell-specific distribution of group I (mGluR1, mGluR5), group II (mGluR2/3) and group III (mGluR4 and mGluR8) mGluR subtypes in human TSC specimens of both cortical tubers and SGCTs, using immunocytochemistry. Strong group I mGluR immunoreactivity (IR) was observed in the large majority of TSC specimens in dysplastic neurons and in giant cells within cortical tubers, as well as in tumor cells within SGCTs. In particular mGluR5 appeared to be most frequently expressed, whereas mGluR1alpha was detected in a subpopulation of neurons and giant cells. Cells expressing mGluR1alpha and mGluR5, demonstrate IR for phospho-S6 ribosomal protein (PS6), which is a marker of the mammalian target of rapamycin (mTOR) pathway activation. Group II and particularly group III mGluR IR was less frequently observed than group I mGluRs in dysplastic neurons and giant cells of tubers and tumor cells of SGCTs. Reactive astrocytes were mainly stained with mGluR5 and mGluR2/3. These findings expand our knowledge concerning the cellular phenotype in cortical tubers and in SGCTs and highlight the role of group I mGluRs as important mediators of glutamate signaling in TSC brain lesions. Individual mGluR subtypes may represent potential pharmacological targets for the treatment of the neurological manifestations associated with TSC brain lesions.
Collapse
Affiliation(s)
- K Boer
- Department of (Neuro)Pathology, Academic Medical Center, University of Amsterdam, The Netherlands
| | | | | | | | | | | | | | | |
Collapse
|
47
|
Koeller HB, Ross ME, Glickstein SB. Cyclin D1 in excitatory neurons of the adult brain enhances kainate-induced neurotoxicity. Neurobiol Dis 2008; 31:230-41. [PMID: 18585919 DOI: 10.1016/j.nbd.2008.04.010] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2008] [Revised: 04/22/2008] [Accepted: 04/25/2008] [Indexed: 12/22/2022] Open
Abstract
G1-phase cyclin D1 (cD1) expression has been documented in post-mitotic neurons undergoing apoptosis, leading others to propose that attempted cell cycle re-entry may induce cell death. Here, cD1 immunoreactivity was found in a subpopulation of healthy excitatory neurons throughout the brain. Most striking was the selective cD1 expression in hippocampal pyramidal neurons, an especially vulnerable cell group. Seizure threshold, cD1 induction and CA1 neuron death were examined following application of kainate (KA) or pentylenetetrazole (PTZ) in cD1 heterozygous (+/-) and wildtype mice to determine whether baseline cD1 correlates with pathology. cD1+/- mice displayed resistance to KA, but not PTZ-induced seizures and had reduced or equivalent cytotoxicity respectively, compared with wildtype. KA administration, but not PTZ, induced cD1 expression. These findings suggest that basal cD1 expression may render hippocampal circuits more susceptible to particular epileptogenic agents and excitotoxic cell death, though cD1 is not a direct precipitant in apoptosis.
Collapse
Affiliation(s)
- Hajira B Koeller
- Graduate Program in Neuroscience, Department of Neurology and Neuroscience, Weill Medical College of Cornell University, 1300 York Avenue, Box 239, New York, NY 10065, USA
| | | | | |
Collapse
|