1
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Sosunov AA, McKhann Ii G, Tang G, Goldman JE. Cytoplasmic vacuolization and ectopic formation of perineuronal nets are characteristic pathologies of cytomegalic neurons in tuberous sclerosis. J Neuropathol Exp Neurol 2024:nlae079. [PMID: 39024216 DOI: 10.1093/jnen/nlae079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/20/2024] Open
Abstract
Cytomegalic neurons, characterized by increased size and a hyperactive mechanistic target of rapamycin complex 1 (mTORC1), are pathognomonic for tuberous sclerosis complex (TSC). To model these neurons, we recently generated a murine Tsc1 conditional knockout model in which Tsc1 deletion in late embryonic radial glia results in neuronal hypertrophy of a subset of isocortical pyramidal neurons. In the current study, we compared the cellular pathology of these cytomegalic neurons to those of the enlarged neurons in human cortical tubers. Neurons from the mice showed unique features, such as cytoplasmic vacuoles associated with Golgi complexes and the ectopic formation of perineuronal nets (PNNs), a feature of inhibitory neurons, rarely present in excitatory cortical neurons. The membranes of these vacuoles were enriched for the plasma membrane proteins CD44, KCC2, and Na+/K+ ATPase, suggesting deficits in Golgi membrane trafficking. These aberrant features in the mouse appeared only after the onset of seizures, probably due to the prolonged seizure activity in the context of constitutive mTORC1 activation. Similar PNNs and cytoplasmic vacuoles were present in the cytomegalic neurons of human cortical tubers. Our findings reveal novel pathological features of Golgi complexes and PNNs in the cytomegalic neurons in TSC.
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Affiliation(s)
- Alexander A Sosunov
- Department of Neurological Surgery, Columbia University Irving Medical Center, New York, NY, United States
| | - Guy McKhann Ii
- Department of Neurological Surgery, Columbia University Irving Medical Center, New York, NY, United States
| | - Guomei Tang
- Department of Neurology, Columbia University Irving Medical Center, New York, NY, United States
| | - James E Goldman
- Department of Pathology and Cell Biology, Columbia University Irving Medical Center, New York, NY, United States
- The Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University Irving Medical Center, New York, NY, United States
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2
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Holmberg JC, Riley VA, Sokolov AM, Mukherjee S, Feliciano DM. Protocol for electroporating and isolating murine (sub)ventricular zone cells for single-nuclei omics. STAR Protoc 2024; 5:103095. [PMID: 38823010 PMCID: PMC11179414 DOI: 10.1016/j.xpro.2024.103095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2024] [Revised: 03/14/2024] [Accepted: 05/08/2024] [Indexed: 06/03/2024] Open
Abstract
In vivo genetic modification of neural stem cells is necessary to model the origins and pathogenesis of neurological disorders. Electroporation is a technique that applies a transient electrical field to direct charged molecules into living cells to genetically modify the mouse brain. Here, we provide a protocol to electroporate the neural stem cells surrounding the neonatal ventricles. We describe subsequent steps to isolate and prepare nuclei from the cells and their cellular progeny for single-nuclei omics. For complete details on the use and execution of this protocol, please refer to Riley et al.1.
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Affiliation(s)
- Jennie C Holmberg
- Department of Biological Sciences, Clemson University, Clemson, SC 29631, USA.
| | - Victoria A Riley
- Department of Biological Sciences, Clemson University, Clemson, SC 29631, USA
| | - Aidan M Sokolov
- Department of Biological Sciences, Clemson University, Clemson, SC 29631, USA
| | - Sulagna Mukherjee
- Department of Biological Sciences, Clemson University, Clemson, SC 29631, USA
| | - David M Feliciano
- Department of Biological Sciences, Clemson University, Clemson, SC 29631, USA; Center for Human Genetics, Clemson University, Greenwood, SC 29646, USA.
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3
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Procházková N, Nguyenová MT, Řehořová M, Kudláček J, Chvojka J, Ziak J, Balaštík M, Otáhal J, Jiruška P, Novák O. NeuroPorator: An open-source, current-limited electroporator for safe in utero gene transfer. J Neurosci Methods 2024; 406:110126. [PMID: 38554786 DOI: 10.1016/j.jneumeth.2024.110126] [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: 12/01/2023] [Revised: 03/13/2024] [Accepted: 03/24/2024] [Indexed: 04/02/2024]
Abstract
BACKGROUND Electroporation is an effective technique for genetic manipulation of cells, both in vitro and in vivo. In utero electroporation (IUE) is a special case, which represents a fine application of this technique to genetically modify specific tissues of embryos during prenatal development. Commercially available electroporators are expensive and not fully customizable. We have designed and produced an inexpensive, open-design, and customizable electroporator optimized for safe IUE. We introduce NeuroPorator. METHOD We used off-the-shelf electrical parts, a single-board microcontroller, and a cheap data logger to build an open-design electroporator. We included a safety circuit to limit the applied electrical current to protect the embryos. We added full documentation, design files, and assembly instructions. RESULT NeuroPorator output is on par with commercially available devices. Furthermore, the adjustable current limiter protects both the embryos and the uterus from overcurrent damage. A built-in data acquisition module provides real-time visualization and recordings of the actual voltage/current pulses applied to each embryo. Function of NeuroPorator has been demonstrated by inducing focal cortical dysplasia in mice. SIGNIFICANCE AND CONCLUSION The simple and fully open design enables quick and cheap construction of the device and facilitates further customization. The features of NeuroPorator can accelerate the IUE technique implementation in any laboratory and speed up its learning curve.
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Affiliation(s)
- Natálie Procházková
- Department of Physiology, Second Faculty of Medicine, Charles University, Plzenska 311, Prague 15000, Czech Republic
| | - Minh-Thao Nguyenová
- Department of Physiology, Second Faculty of Medicine, Charles University, Plzenska 311, Prague 15000, Czech Republic
| | - Monika Řehořová
- Department of Physiology, Second Faculty of Medicine, Charles University, Plzenska 311, Prague 15000, Czech Republic
| | - Jan Kudláček
- Department of Physiology, Second Faculty of Medicine, Charles University, Plzenska 311, Prague 15000, Czech Republic
| | - Jan Chvojka
- Department of Physiology, Second Faculty of Medicine, Charles University, Plzenska 311, Prague 15000, Czech Republic
| | - Jakub Ziak
- Laboratory of Molecular Neurobiology, Institute of Physiology, The Czech Academy of Sciences, Videnska 1083, Prague 14200, Czech Republic
| | - Martin Balaštík
- Laboratory of Molecular Neurobiology, Institute of Physiology, The Czech Academy of Sciences, Videnska 1083, Prague 14200, Czech Republic
| | - Jakub Otáhal
- Department of Pathophysiology, Second Faculty of Medicine, Charles University, Plzenska 311, Prague 15000, Czech Republic
| | - Přemysl Jiruška
- Department of Physiology, Second Faculty of Medicine, Charles University, Plzenska 311, Prague 15000, Czech Republic
| | - Ondřej Novák
- Department of Physiology, Second Faculty of Medicine, Charles University, Plzenska 311, Prague 15000, Czech Republic.
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4
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Garone C, De Giorgio F, Carli S. Mitochondrial metabolism in neural stem cells and implications for neurodevelopmental and neurodegenerative diseases. J Transl Med 2024; 22:238. [PMID: 38438847 PMCID: PMC10910780 DOI: 10.1186/s12967-024-05041-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2023] [Accepted: 02/25/2024] [Indexed: 03/06/2024] Open
Abstract
Mitochondria are cytoplasmic organelles having a fundamental role in the regulation of neural stem cell (NSC) fate during neural development and maintenance.During embryonic and adult neurogenesis, NSCs undergo a metabolic switch from glycolytic to oxidative phosphorylation with a rise in mitochondrial DNA (mtDNA) content, changes in mitochondria shape and size, and a physiological augmentation of mitochondrial reactive oxygen species which together drive NSCs to proliferate and differentiate. Genetic and epigenetic modifications of proteins involved in cellular differentiation (Mechanistic Target of Rapamycin), proliferation (Wingless-type), and hypoxia (Mitogen-activated protein kinase)-and all connected by the common key regulatory factor Hypoxia Inducible Factor-1A-are deemed to be responsible for the metabolic shift and, consequently, NSC fate in physiological and pathological conditions.Both primary mitochondrial dysfunction due to mutations in nuclear DNA or mtDNA or secondary mitochondrial dysfunction in oxidative phosphorylation (OXPHOS) metabolism, mitochondrial dynamics, and organelle interplay pathways can contribute to the development of neurodevelopmental or progressive neurodegenerative disorders.This review analyses the physiology and pathology of neural development starting from the available in vitro and in vivo models and highlights the current knowledge concerning key mitochondrial pathways involved in this process.
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Affiliation(s)
- C Garone
- Department of Medical and Surgical Sciences, Alma Mater Studiorum-University of Bologna, Bologna, Italy.
- IRCCS Istituto Delle Scienze Neurologiche di Bologna, UO Neuropsichiatria Dell'età Pediatrica, Bologna, Italy.
| | - F De Giorgio
- Department of Medical and Surgical Sciences, Alma Mater Studiorum-University of Bologna, Bologna, Italy
| | - S Carli
- Department of Medical and Surgical Sciences, Alma Mater Studiorum-University of Bologna, Bologna, Italy
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5
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Riley VA, Shankar V, Holmberg JC, Sokolov AM, Neckles VN, Williams K, Lyman R, Mackay TF, Feliciano DM. Tsc2 coordinates neuroprogenitor differentiation. iScience 2023; 26:108442. [PMID: 38107199 PMCID: PMC10724693 DOI: 10.1016/j.isci.2023.108442] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Revised: 09/22/2023] [Accepted: 11/09/2023] [Indexed: 12/19/2023] Open
Abstract
Neural stem cells (NSCs) of the ventricular-subventricular zone (V-SVZ) generate numerous cell types. The uncoupling of mRNA transcript availability and translation occurs during the progression from stem to differentiated states. The mTORC1 kinase pathway acutely controls proteins that regulate mRNA translation. Inhibiting mTORC1 during differentiation is hypothesized to be critical for brain development since somatic mutations of mTORC1 regulators perturb brain architecture. Inactivating mutations of TSC1 or TSC2 genes cause tuberous sclerosis complex (TSC). TSC patients have growths near the striatum and ventricles. Here, it is demonstrated that V-SVZ NSC Tsc2 inactivation causes striatal hamartomas. Tsc2 removal altered translation factors, translatomes, and translational efficiency. Single nuclei RNA sequencing following in vivo loss of Tsc2 revealed changes in NSC activation states. The inability to decouple mRNA transcript availability and translation delayed differentiation leading to the retention of immature phenotypes in hamartomas. Taken together, Tsc2 is required for translational repression and differentiation.
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Affiliation(s)
- Victoria A. Riley
- Department of Biological Sciences, Clemson University, Clemson, SC, USA
| | - Vijay Shankar
- Department of Biochemistry and Genetics, Clemson University, Clemson, SC, USA
- Center for Human Genetics, Clemson University, Greenwood, SC, USA
| | | | - Aidan M. Sokolov
- Department of Biological Sciences, Clemson University, Clemson, SC, USA
| | | | - Kaitlyn Williams
- Clemson University Genomics and Bioinformatics Facility (CUGBF), Clemson University, Clemson, SC, USA
| | - Rachel Lyman
- Department of Biochemistry and Genetics, Clemson University, Clemson, SC, USA
- Center for Human Genetics, Clemson University, Greenwood, SC, USA
| | - Trudy F.C. Mackay
- Department of Biochemistry and Genetics, Clemson University, Clemson, SC, USA
- Center for Human Genetics, Clemson University, Greenwood, SC, USA
| | - David M. Feliciano
- Department of Biological Sciences, Clemson University, Clemson, SC, USA
- Center for Human Genetics, Clemson University, Greenwood, SC, USA
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6
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Kittock CM, Pilaz LJ. Advances in in utero electroporation. Dev Neurobiol 2023; 83:73-90. [PMID: 36861639 DOI: 10.1002/dneu.22910] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 02/02/2023] [Accepted: 02/21/2023] [Indexed: 03/03/2023]
Abstract
In utero electroporation (IUE) is a technique developed in the early 2000s to transfect the neurons and neural progenitors of embryonic brains, thus enabling continued development in utero and subsequent analyses of neural development. Early IUE experiments focused on ectopic expression of plasmid DNA to analyze parameters such as neuron morphology and migration. Recent advances made in other fields, such as CRISPR/CAS9 genome editing, have been incorporated into IUE techniques as they were developed. Here, we provide a general review of the mechanics and techniques involved in IUE and explore the breadth of approaches that can be used in conjunction with IUE to study cortical development in a rodent model, with a focus on the novel advances in IUE techniques. We also highlight a few cases that exemplify the potential of IUE to study a broad range of questions in neural development.
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Affiliation(s)
- Claire M Kittock
- Pediatrics and Rare Diseases Group, Sanford Research, Sioux Falls, South Dakota, USA
- Sanford School of Medicine, University of South Dakota, Sioux Falls, South Dakota, USA
| | - Louis-Jan Pilaz
- Pediatrics and Rare Diseases Group, Sanford Research, Sioux Falls, South Dakota, USA
- Sanford School of Medicine, University of South Dakota, Sioux Falls, South Dakota, USA
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7
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Abstract
The current understanding of neurological diseases is derived mostly from direct analysis of patients and from animal models of disease. However, most patient studies do not capture the earliest stages of disease development and offer limited opportunities for experimental intervention, so rarely yield complete mechanistic insights. The use of animal models relies on evolutionary conservation of pathways involved in disease and is limited by an inability to recreate human-specific processes. In vitro models that are derived from human pluripotent stem cells cultured in 3D have emerged as a new model system that could bridge the gap between patient studies and animal models. In this Review, we summarize how such organoid models can complement classical approaches to accelerate neurological research. We describe our current understanding of neurodevelopment and how this process differs between humans and other animals, making human-derived models of disease essential. We discuss different methodologies for producing organoids and how organoids can be and have been used to model neurological disorders, including microcephaly, Zika virus infection, Alzheimer disease and other neurodegenerative disorders, and neurodevelopmental diseases, such as Timothy syndrome, Angelman syndrome and tuberous sclerosis. We also discuss the current limitations of organoid models and outline how organoids can be used to revolutionize research into the human brain and neurological diseases. In this Review, Eichmüller and Knoblich discuss how human brain organoids can recapitulate the unique processes that occur in human brain development and how they can complement classical approaches to revolutionize research into neurological diseases. Development of the human brain involves unique processes that are relevant to neurological disease but cannot be studied in animal models, so alternative model systems are required. Organoids are 3D human cell culture models that originate from pluripotent stem cells and recapitulate the hallmarks of human neurodevelopment, enabling studies of human brain development in vitro. Specific mutations can be introduced into organoids to study their effects on neurodevelopment; combined with high-throughput screening methods, this approach can determine the disease relevance of mutations in human tissue. To study specific diseases, brain organoids can be generated from induced pluripotent stem cells from individual patients, thereby preserving the specific genetic background of the individual and generating an insightful model. Through recapitulation of previously inaccessible periods of human brain development, brain organoids have enabled identification of novel mechanisms that underlie neurodevelopmental, neurodegenerative and infectious diseases. Combining organoids, patient research and animal models enables us to take full advantage of each of these systems and will provide unprecedented insights into neurodevelopment and neurological diseases.
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8
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Gataullina S, Galvani G, Touchet S, Nous C, Lemaire E, Laschet J, Chiron C, Dulac O, Dossi E, Brion JD, Messaoudi S, Alami M, Huberfeld G. GluN2C
selective inhibition is a target to develop new antiepileptic compounds. Epilepsia 2022; 63:2911-2924. [PMID: 36054371 DOI: 10.1111/epi.17396] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 08/17/2022] [Accepted: 08/17/2022] [Indexed: 11/28/2022]
Abstract
OBJECTIVE Many early-onset epilepsies present as developmental and epileptic encephalopathy associated with refractory seizures, altered psychomotor development, and disorganized interictal cortical activity. Abnormal upregulation of specific N-methyl-d-aspartate receptor (NMDA-R) subunits is being disentangled as one of the mechanisms of severe early-onset epilepsies. In tuberous sclerosis complex (TSC), upregulation of the GluN2C subunit of the NMDA-R with slow deactivation kinetic results in increased neuronal excitation and synchronization. METHODS Starting from an available GluN2C/D antagonist, NMDA-R-modulating compounds were developed and screened using a patch clamp on neuronal culture to select those with the strongest inhibitory effect on glutamatergic NMDA currents. For these selected compounds, blood pharmacokinetics and passage through the blood-brain barrier were studied. We tested the effect of the most promising compounds on epileptic activity in Tsc1+/- mice brain slices with multielectrode array, and then in vivo at postnatal ages P14-P17, comparable with the usual age at epilepsy onset in human TSC. RESULTS Using a double-electrode voltage clamp on isolated NMDA currents, we identified the most prominent antagonists of the GluN2C subunit with no effect on GluN2A as a means of preventing side effects. The best compound passing through the blood-brain barrier was selected. Applied in vivo in six Tsc1+/- mice at P14-P17, this compound reduced or completely stopped spontaneous seizures in four of them, and decreased the background activity disorganization. Furthermore, ictal-like discharges stopped on a human brain sample from an infant with epilepsy due to TSC. INTERPRETATION Subunit-selective inhibition is a valuable target for developing drugs for severe epilepsies resulting from an upregulation of NMDA-R subunit-mediated transmission.
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Affiliation(s)
- S. Gataullina
- Service d’explorations fonctionnelles multidisciplinaires Centre de médecine du sommeil, Antoine Béclère Hospital, APHP, Université Paris Saclay Clamart France
| | - G. Galvani
- AdPueriVitam (APV), Antony France
- Université de Lorraine CNRS, L2CM Nancy France
| | - S. Touchet
- AdPueriVitam (APV), Antony France
- Université de Lorraine CNRS, L2CM Nancy France
| | - C. Nous
- Institut de la Vision, UFR Sciences et Technologies Paris France
| | | | | | - C. Chiron
- Inserm U1141, Paris & APHP, Neuropediatrics, Necker Hospital Paris France
| | - O. Dulac
- AdPueriVitam (APV), Antony France
| | - E. Dossi
- Center for Interdisciplinary Research in Biology, Collège de France, CNRS UMR 7241, INSERM U1050 Université PSL Paris France
| | - J. D. Brion
- Université Paris‐Saclay CNRS UMR 8076, BioCIS Châtenay‐Malabry France
| | - S. Messaoudi
- Université Paris‐Saclay CNRS UMR 8076, BioCIS Châtenay‐Malabry France
| | - M. Alami
- Université Paris‐Saclay CNRS UMR 8076, BioCIS Châtenay‐Malabry France
| | - G. Huberfeld
- Center for Interdisciplinary Research in Biology, Collège de France, CNRS UMR 7241, INSERM U1050 Université PSL Paris France
- Neurology Department, Hôpital Fondation Adolphe de Rothschild Paris France
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9
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Wu X, Sosunov AA, Lado W, Teoh JJ, Ham A, Li H, Al-Dalahmah O, Gill BJA, Arancio O, Schevon CA, Frankel WN, McKhann GM, Sulzer D, Goldman JE, Tang G. Synaptic hyperexcitability of cytomegalic pyramidal neurons contributes to epileptogenesis in tuberous sclerosis complex. Cell Rep 2022; 40:111085. [PMID: 35858542 PMCID: PMC9376014 DOI: 10.1016/j.celrep.2022.111085] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 02/15/2022] [Accepted: 06/22/2022] [Indexed: 11/27/2022] Open
Abstract
Tuberous sclerosis complex (TSC) is a developmental disorder associated with epilepsy, autism, and cognitive impairment. Despite inactivating mutations in the TSC1 or TSC2 genes and hyperactive mechanistic target of rapamycin (mTOR) signaling, the mechanisms underlying TSC-associated neurological symptoms remain incompletely understood. Here we generate a Tsc1 conditional knockout (CKO) mouse model in which Tsc1 inactivation in late embryonic radial glia causes social and cognitive impairment and spontaneous seizures. Tsc1 depletion occurs in a subset of layer 2/3 cortical pyramidal neurons, leading to development of cytomegalic pyramidal neurons (CPNs) that mimic dysplastic neurons in human TSC, featuring abnormal dendritic and axonal overgrowth, enhanced glutamatergic synaptic transmission, and increased susceptibility to seizure-like activities. We provide evidence that enhanced synaptic excitation in CPNs contributes to cortical hyperexcitability and epileptogenesis. In contrast, astrocytic regulation of synapse formation and synaptic transmission remains unchanged after late embryonic radial glial Tsc1 inactivation, and astrogliosis evolves secondary to seizures. Wu et al. demonstrate that Tsc1 inactivation in late embryonic radial glial cells (RGCs) produces cytomegalic pyramidal neurons that mimic TSC-like dysplastic neurons. They find that enhanced excitatory synaptic transmission in Tsc1-null cytomegalic pyramidal neurons contributes to cortical hyperexcitability and epileptogenesis.
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Affiliation(s)
- Xiaoping Wu
- Department of Neurological Surgery, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Alexander A Sosunov
- Department of Neurological Surgery, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Wudu Lado
- Department of Neurology, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Jia Jie Teoh
- Institute for Genomic Medicine, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Ahrom Ham
- Department of Neurology, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Hongyu Li
- Department of Neurology, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Osama Al-Dalahmah
- Department of Pathology and Cell Biology, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Brian J A Gill
- Department of Neurological Surgery, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Ottavio Arancio
- Department of Pathology and Cell Biology, Columbia University Irving Medical Center, New York, NY 10032, USA; Department of Medicine, Columbia University Irving Medical Center, New York, NY 10032, USA; The Taub Institute, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Catherine A Schevon
- Department of Neurology, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Wayne N Frankel
- Institute for Genomic Medicine, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Guy M McKhann
- Department of Neurological Surgery, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - David Sulzer
- Department of Psychiatry, Columbia University Irving Medical Center, New York, NY 10032, USA; Department of Pharmacology, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - James E Goldman
- Department of Pathology and Cell Biology, Columbia University Irving Medical Center, New York, NY 10032, USA; The Taub Institute, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Guomei Tang
- Department of Neurology, Columbia University Irving Medical Center, New York, NY 10032, USA.
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10
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Park SM, Roache CE, Iffland PH, Moldenhauer HJ, Matychak KK, Plante AE, Lieberman AG, Crino PB, Meredith A. BK channel properties correlate with neurobehavioral severity in three KCNMA1-linked channelopathy mouse models. eLife 2022; 11:e77953. [PMID: 35819138 PMCID: PMC9275823 DOI: 10.7554/elife.77953] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Accepted: 06/01/2022] [Indexed: 12/14/2022] Open
Abstract
KCNMA1 forms the pore of BK K+ channels, which regulate neuronal and muscle excitability. Recently, genetic screening identified heterozygous KCNMA1 variants in a subset of patients with debilitating paroxysmal non-kinesigenic dyskinesia, presenting with or without epilepsy (PNKD3). However, the relevance of KCNMA1 mutations and the basis for clinical heterogeneity in PNKD3 has not been established. Here, we evaluate the relative severity of three KCNMA1 patient variants in BK channels, neurons, and mice. In heterologous cells, BKN999S and BKD434G channels displayed gain-of-function (GOF) properties, whereas BKH444Q channels showed loss-of-function (LOF) properties. The relative degree of channel activity was BKN999S > BKD434G>WT > BKH444Q. BK currents and action potential firing were increased, and seizure thresholds decreased, in Kcnma1N999S/WT and Kcnma1D434G/WT transgenic mice but not Kcnma1H444Q/WT mice. In a novel behavioral test for paroxysmal dyskinesia, the more severely affected Kcnma1N999S/WT mice became immobile after stress. This was abrogated by acute dextroamphetamine treatment, consistent with PNKD3-affected individuals. Homozygous Kcnma1D434G/D434G mice showed similar immobility, but in contrast, homozygous Kcnma1H444Q/H444Q mice displayed hyperkinetic behavior. These data establish the relative pathogenic potential of patient alleles as N999S>D434G>H444Q and validate Kcnma1N999S/WT mice as a model for PNKD3 with increased seizure propensity.
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Affiliation(s)
- Su Mi Park
- Department of Physiology, University of Maryland School of MedicineBaltimoreUnited States
| | - Cooper E Roache
- Department of Physiology, University of Maryland School of MedicineBaltimoreUnited States
| | - Philip H Iffland
- Department of Neurology, University of Maryland School of MedicineBaltimoreUnited States
| | - Hans J Moldenhauer
- Department of Physiology, University of Maryland School of MedicineBaltimoreUnited States
| | - Katia K Matychak
- Department of Physiology, University of Maryland School of MedicineBaltimoreUnited States
| | - Amber E Plante
- Department of Physiology, University of Maryland School of MedicineBaltimoreUnited States
| | - Abby G Lieberman
- Department of Pharmacology, University of Maryland School of MedicineBaltimoreUnited States
| | - Peter B Crino
- Department of Neurology, University of Maryland School of MedicineBaltimoreUnited States
| | - Andrea Meredith
- Department of Physiology, University of Maryland School of MedicineBaltimoreUnited States
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11
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Nguyen LH, Bordey A. Current Review in Basic Science: Animal Models of Focal Cortical Dysplasia and Epilepsy. Epilepsy Curr 2022; 22:234-240. [PMID: 36187145 PMCID: PMC9483763 DOI: 10.1177/15357597221098230] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Focal cortical dysplasia (FCD) is a malformation of cortical development that is a prevalent cause of intractable epilepsy in children. Of the three FCD subtypes, understanding the etiology and pathogenesis of FCD type II has seen the most progress owing to the recent advances in identifying gene mutations along the mTOR signaling pathway as a frequent cause of this disorder. Accordingly, numerous animal models of FCD type II based on genetic manipulation of the mTOR signaling pathway have emerged to investigate the mechanisms of epileptogenesis and novel therapeutics for epilepsy. These include transgenic and in utero electroporation-based animal models. Here, we review the histopathological and electroclinical features of existing FCD type II animal models and discuss the scientific and technical considerations, clinical applications, and limitations of current models. We also highlight other models of FCD based on early life acquired factors.
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Affiliation(s)
- Lena H. Nguyen
- Departments of Neurosurgery and Cellular & Molecular
Physiology, Yale University School of
Medicine, New Haven, CT, USA
| | - Angélique Bordey
- Departments of Neurosurgery and Cellular & Molecular
Physiology, Yale University School of
Medicine, New Haven, CT, USA
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12
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Rare CACNA1H and RELN variants interact through mTORC1 pathway in oligogenic autism spectrum disorder. Transl Psychiatry 2022; 12:234. [PMID: 35668055 PMCID: PMC9170683 DOI: 10.1038/s41398-022-01997-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Revised: 05/19/2022] [Accepted: 05/25/2022] [Indexed: 11/09/2022] Open
Abstract
Oligogenic inheritance of autism spectrum disorder (ASD) has been supported by several studies. However, little is known about how the risk variants interact and converge on causative neurobiological pathways. We identified in an ASD proband deleterious compound heterozygous missense variants in the Reelin (RELN) gene, and a de novo splicing variant in the Cav3.2 calcium channel (CACNA1H) gene. Here, by using iPSC-derived neural progenitor cells (NPCs) and a heterologous expression system, we show that the variant in Cav3.2 leads to increased calcium influx into cells, which overactivates mTORC1 pathway and, consequently, further exacerbates the impairment of Reelin signaling. Also, we show that Cav3.2/mTORC1 overactivation induces proliferation of NPCs and that both mutant Cav3.2 and Reelin cause abnormal migration of these cells. Finally, analysis of the sequencing data from two ASD cohorts-a Brazilian cohort of 861 samples, 291 with ASD; the MSSNG cohort of 11,181 samples, 5,102 with ASD-revealed that the co-occurrence of risk variants in both alleles of Reelin pathway genes and in one allele of calcium channel genes confer significant liability for ASD. Our results support the notion that genes with co-occurring deleterious variants tend to have interconnected pathways underlying oligogenic forms of ASD.
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Eichmüller OL, Corsini NS, Vértesy Á, Morassut I, Scholl T, Gruber VE, Peer AM, Chu J, Novatchkova M, Hainfellner JA, Paredes MF, Feucht M, Knoblich JA. Amplification of human interneuron progenitors promotes brain tumors and neurological defects. Science 2022; 375:eabf5546. [PMID: 35084981 DOI: 10.1126/science.abf5546] [Citation(s) in RCA: 55] [Impact Index Per Article: 27.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Evolutionary development of the human brain is characterized by the expansion of various brain regions. Here, we show that developmental processes specific to humans are responsible for malformations of cortical development (MCDs), which result in developmental delay and epilepsy in children. We generated a human cerebral organoid model for tuberous sclerosis complex (TSC) and identified a specific neural stem cell type, caudal late interneuron progenitor (CLIP) cells. In TSC, CLIP cells over-proliferate, generating excessive interneurons, brain tumors, and cortical malformations. Epidermal growth factor receptor inhibition reduces tumor burden, identifying potential treatment options for TSC and related disorders. The identification of CLIP cells reveals the extended interneuron generation in the human brain as a vulnerability for disease. In addition, this work demonstrates that analyzing MCDs can reveal fundamental insights into human-specific aspects of brain development.
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Affiliation(s)
- Oliver L Eichmüller
- Institute of Molecular Biotechnology (IMBA), Austrian Academy of Sciences, Vienna Biocenter (VBC), Vienna, Austria.,University of Heidelberg, Heidelberg, Germany
| | - Nina S Corsini
- Institute of Molecular Biotechnology (IMBA), Austrian Academy of Sciences, Vienna Biocenter (VBC), Vienna, Austria
| | - Ábel Vértesy
- Institute of Molecular Biotechnology (IMBA), Austrian Academy of Sciences, Vienna Biocenter (VBC), Vienna, Austria
| | - Ilaria Morassut
- Institute of Molecular Biotechnology (IMBA), Austrian Academy of Sciences, Vienna Biocenter (VBC), Vienna, Austria
| | - Theresa Scholl
- Department of Pediatric and Adolescent Medicine, Medical University of Vienna, Vienna, Austria
| | | | - Angela M Peer
- Institute of Molecular Biotechnology (IMBA), Austrian Academy of Sciences, Vienna Biocenter (VBC), Vienna, Austria
| | - Julia Chu
- Department of Neurology, University of California, San Francisco, San Francisco, CA, USA
| | - Maria Novatchkova
- Institute of Molecular Biotechnology (IMBA), Austrian Academy of Sciences, Vienna Biocenter (VBC), Vienna, Austria
| | | | - Mercedes F Paredes
- Department of Neurology, University of California, San Francisco, San Francisco, CA, USA
| | - Martha Feucht
- Department of Pediatric and Adolescent Medicine, Medical University of Vienna, Vienna, Austria
| | - Jürgen A Knoblich
- Institute of Molecular Biotechnology (IMBA), Austrian Academy of Sciences, Vienna Biocenter (VBC), Vienna, Austria.,Department of Neurology, Medical University of Vienna, Vienna, Austria
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14
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Abstract
[Figure: see text].
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Affiliation(s)
- Rebecca A Ihrie
- Cell & Developmental Biology and Neurological Surgery, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Elizabeth P Henske
- Pulmonary and Critical Care Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
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15
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Deb BK, Bateup HS. Modeling Somatic Mutations Associated With Neurodevelopmental Disorders in Human Brain Organoids. Front Mol Neurosci 2022; 14:787243. [PMID: 35058746 PMCID: PMC8764387 DOI: 10.3389/fnmol.2021.787243] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 11/30/2021] [Indexed: 11/13/2022] Open
Abstract
Neurodevelopmental disorders (NDDs) are a collection of diseases with early life onset that often present with developmental delay, cognitive deficits, and behavioral conditions. In some cases, severe outcomes such as brain malformations and intractable epilepsy can occur. The mutations underlying NDDs may be inherited or de novo, can be gain- or loss-of-function, and can affect one or more genes. Recent evidence indicates that brain somatic mutations contribute to several NDDs, in particular malformations of cortical development. While advances in sequencing technologies have enabled the detection of these somatic mutations, the mechanisms by which they alter brain development and function are not well understood due to limited model systems that recapitulate these events. Human brain organoids have emerged as powerful models to study the early developmental events of the human brain. Brain organoids capture the developmental progression of the human brain and contain human-enriched progenitor cell types. Advances in human stem cell and genome engineering provide an opportunity to model NDD-associated somatic mutations in brain organoids. These organoids can be tracked throughout development to understand the impact of somatic mutations on early human brain development and function. In this review, we discuss recent evidence that somatic mutations occur in the developing human brain, that they can lead to NDDs, and discuss how they could be modeled using human brain organoids.
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Affiliation(s)
- Bipan K. Deb
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, United States
| | - Helen S. Bateup
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, United States
- Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA, United States
- Chan Zuckerberg Biohub, San Francisco, CA, United States
- *Correspondence: Helen S. Bateup
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16
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Tong X, Wang X, Qin L, Zhou J, Guan Y, Teng P, Wang J, Yang Y, Li T, Luan G. Vagus nerve stimulation for drug-resistant epilepsy induced by tuberous sclerosis complex. Epilepsy Behav 2022; 126:108431. [PMID: 34883463 DOI: 10.1016/j.yebeh.2021.108431] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 10/22/2021] [Accepted: 11/05/2021] [Indexed: 11/03/2022]
Abstract
OBJECTIVE This study investigated the dynamic and long-term efficacy of vagus nerve stimulation (VNS) in patients with drug-resistant epilepsy (DRE) induced by tuberous sclerosis complex (TSC). In addition, the impact of VNS on cognition and emotion after a one-year follow-up was evaluated. METHODS A total of 17 patients diagnosed with DRE induced by TSC were retrospectively recruited between 2008 and 2019. Dynamic changes in seizure frequency were observed in the responders (≥50% reduction of seizure frequency at last follow-up) and non-responders. Clinical characteristics and seizure outcomes were comprehensively analyzed to determine factors associated with seizure outcomes. The Wechsler intelligence scale was applied in a subgroup of six pediatric patients, whereas the Self-rating Anxiety Scale (SAS) and Self-rating Depression Scale (SDS) were assessed in a subgroup of nine patients to determine the impact of VNS therapy on cognitive performance and emotional state. RESULTS The follow-up duration for the 17 patients who underwent VNS treatment ranged from 0.5 to 10 years (mean ± SD: 4.1 ± 3.2 years). Monthly seizures decreased significantly from three months to four years post-treatment (p < 0.05). At the last follow-up, 70.6% of the patients achieved at least a 50% reduction in seizure frequency, and three patients were completely seizure free. Comparatively, non-responder patients experienced deterioration of seizure frequency after the first year. Notably, after one-year follow-up the mean standard score of full-scale intelligence quotient increased from 67.33 to 69.5 (p = 0.078) while the mean, standard score of SDS decreased from 49.22 to 45.67 (p = 0.003) compared to preoperative neuropsychological evaluation results. CONCLUSION VNS is a safe and effective treatment for patients with DRE caused by TSC. Although early outcomes were encouraging, a follow-up of at least one-year was required to predict long-term outcomes in patients receiving VNS treatment. Moreover, VNS may improve depressive mood in patients with DRE caused by TSC. Further investigations are needed to validate the present results.
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Affiliation(s)
- Xuezhi Tong
- Department of Neurosurgery, Sanbo Brain Hospital, Capital Medical University, Beijing 100093, China
| | - Xiongfei Wang
- Department of Neurosurgery, Sanbo Brain Hospital, Capital Medical University, Beijing 100093, China; Beijing Key Laboratory of Epilepsy, Beijing 100093, China; Epilepsy Institute, Beijing Institute for Brain Disorders, Beijing 100093, China
| | - Lang Qin
- McGovern Institute for Brain Research, Peking University, Beijing 100093, China; Center for MRI Research, Peking University, Beijing 100093, China
| | - Jian Zhou
- Department of Neurosurgery, Sanbo Brain Hospital, Capital Medical University, Beijing 100093, China
| | - Yuguang Guan
- Department of Neurosurgery, Sanbo Brain Hospital, Capital Medical University, Beijing 100093, China
| | - Pengfei Teng
- Department of Neurosurgery, Sanbo Brain Hospital, Capital Medical University, Beijing 100093, China
| | - Jing Wang
- Department of Neurology, Sanbo Brain Hospital, Capital Medical University, Beijing 100093, China
| | - Yujiao Yang
- Department of Neurology, Sanbo Brain Hospital, Capital Medical University, Beijing 100093, China
| | - Tianfu Li
- Epilepsy Institute, Beijing Institute for Brain Disorders, Beijing 100093, China; Department of Neurology, Sanbo Brain Hospital, Capital Medical University, Beijing 100093, China
| | - Guoming Luan
- Department of Neurosurgery, Sanbo Brain Hospital, Capital Medical University, Beijing 100093, China; Beijing Key Laboratory of Epilepsy, Beijing 100093, China; Epilepsy Institute, Beijing Institute for Brain Disorders, Beijing 100093, China.
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17
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Koene LM, Niggl E, Wallaard I, Proietti-Onori M, Rotaru DC, Elgersma Y. Identifying the temporal electrophysiological and molecular changes that contribute to TSC-associated epileptogenesis. JCI Insight 2021; 6:150120. [PMID: 34877936 PMCID: PMC8675202 DOI: 10.1172/jci.insight.150120] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Accepted: 10/27/2021] [Indexed: 11/17/2022] Open
Abstract
Tuberous sclerosis complex (TSC), caused by heterozygous mutations in TSC1 or TSC2, frequently results in intractable epilepsy. Here, we made use of an inducible Tsc1-knockout mouse model, allowing us to study electrophysiological and molecular changes of Tsc1-induced epileptogenesis over time. We recorded from pyramidal neurons in the hippocampus and somatosensory cortex (L2/L3) and combined this with an analysis of transcriptome changes during epileptogenesis. Deletion of Tsc1 resulted in hippocampus-specific changes in excitability and adaptation, which emerged before seizure onset and progressed over time. All phenotypes were rescued after early treatment with rapamycin, an mTOR inhibitor. Later in epileptogenesis, we observed a hippocampal increase of excitation-to-inhibition ratio. These cellular changes were accompanied by dramatic transcriptional changes, especially after seizure onset. Most of these changes were rescued upon rapamycin treatment. Of the genes encoding ion channels or belonging to the Gene Ontology term action potential, 27 were differentially expressed just before seizure onset, suggesting a potential driving role in epileptogenesis. Our data highlight the complex changes driving epileptogenesis in TSC, including the changed expression of multiple ion channels. Our study emphasizes inhibition of the TSC/mTOR signaling pathway as a promising therapeutic approach to target epilepsy in patients with TSC.
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Synaptic Alterations in a Transgenic Model of Tuberous Sclerosis Complex: Relevance to Autism Spectrum Disorders. Int J Mol Sci 2021; 22:ijms221810058. [PMID: 34576223 PMCID: PMC8466868 DOI: 10.3390/ijms221810058] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Revised: 09/08/2021] [Accepted: 09/14/2021] [Indexed: 01/02/2023] Open
Abstract
Tuberous sclerosis complex (TSC) is a rare, multi-system genetic disease with serious neurological and mental symptoms, including autism. Mutations in the TSC1/TSC2 genes lead to the overactivation of mTOR signalling, which is also linked to nonsyndromic autism. Our aim was to analyse synaptic pathology in a transgenic model of TSC: two-month-old male B6;129S4-Tsc2tm1Djk/J mice with Tsc2 haploinsufficiency. Significant brain-region-dependent alterations in the expression of several synaptic proteins were identified. The most prominent changes were observed in the immunoreactivity of presynaptic VAMP1/2 (ca. 50% increase) and phospho-synapsin-1 (Ser62/67) (ca. 80% increase). Transmission electron microscopy demonstrated serious ultrastructural abnormalities in synapses such as a blurred structure of synaptic density and a significantly increased number of synaptic vesicles. The impairment of synaptic mitochondrial ultrastructure was represented by excessive elongation, swelling, and blurred crista contours. Polyribosomes in the cytoplasm and swollen Golgi apparatus suggest possible impairment of protein metabolism. Moreover, the delamination of myelin and the presence of vacuolar structures in the cell nucleus were observed. We also report that Tsc2+/- mice displayed increased brain weights and sizes. The behavioural analysis demonstrated the impairment of memory function, as established in the novel object recognition test. To summarise, our data indicate serious synaptic impairment in the brains of male Tsc2+/- mice.
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19
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Benthall KN, Cording KR, Agopyan-Miu AHCW, Wong CD, Chen EY, Bateup HS. Loss of Tsc1 from striatal direct pathway neurons impairs endocannabinoid-LTD and enhances motor routine learning. Cell Rep 2021; 36:109511. [PMID: 34380034 PMCID: PMC8404511 DOI: 10.1016/j.celrep.2021.109511] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Revised: 05/28/2021] [Accepted: 07/21/2021] [Indexed: 02/08/2023] Open
Abstract
Tuberous sclerosis complex (TSC) is a neurodevelopmental disorder that often presents with psychiatric conditions, including autism spectrum disorder (ASD). ASD is characterized by restricted, repetitive, and inflexible behaviors, which may result from abnormal activity in striatal circuits that mediate motor learning and action selection. To test whether altered striatal activity contributes to aberrant motor behaviors in the context of TSC, we conditionally deleted Tsc1 from direct or indirect pathway striatal projection neurons (dSPNs or iSPNs, respectively). We find that dSPN-specific loss of Tsc1 impairs endocannabinoid-mediated long-term depression (eCB-LTD) at cortico-dSPN synapses and strongly enhances corticostriatal synaptic drive, which is not observed in iSPNs. dSPN-Tsc1 KO, but not iSPN-Tsc1 KO, mice show enhanced motor learning, a phenotype observed in several mouse models of ASD. These findings demonstrate that dSPNs are particularly sensitive to Tsc1 loss and suggest that enhanced corticostriatal activation may contribute to altered motor behaviors in TSC.
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Affiliation(s)
- Katelyn N Benthall
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Katherine R Cording
- Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA 94720, USA
| | | | - Corinna D Wong
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Emily Y Chen
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Helen S Bateup
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA; Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA 94720, USA; Chan Zuckerberg Biohub, San Francisco, CA 94158, USA.
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20
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Bassetti D, Luhmann HJ, Kirischuk S. Effects of Mutations in TSC Genes on Neurodevelopment and Synaptic Transmission. Int J Mol Sci 2021; 22:ijms22147273. [PMID: 34298906 PMCID: PMC8305053 DOI: 10.3390/ijms22147273] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Revised: 07/02/2021] [Accepted: 07/04/2021] [Indexed: 12/11/2022] Open
Abstract
Mutations in TSC1 or TSC2 genes are linked to alterations in neuronal function which ultimately lead to the development of a complex neurological phenotype. Here we review current research on the effects that reduction in TSC1 or TSC2 can produce on the developing neural network. A crucial feature of the disease pathophysiology appears to be an early deviation from typical neurodevelopment, in the form of structural abnormalities. Epileptic seizures are one of the primary early manifestation of the disease in the CNS, followed by intellectual deficits and autism spectrum disorders (ASD). Research using mouse models suggests that morphological brain alterations might arise from the interaction of different cellular types, and hyperexcitability in the early postnatal period might be transient. Moreover, the increased excitation-to-inhibition ratio might represent a transient compensatory adjustment to stabilize the developing network rather than a primary factor for the development of ASD symptoms. The inhomogeneous results suggest region-specificity as well as an evolving picture of functional alterations along development. Furthermore, ASD symptoms and epilepsy might originate from different but potentially overlapping mechanisms, which can explain recent observations obtained in patients. Potential treatment is determined not only by the type of medicament, but also by the time point of treatment.
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21
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Nguyen LH, Bordey A. Corrigendum: Convergent and Divergent Mechanisms of Epileptogenesis in mTORopathies. Front Neuroanat 2021; 15:715363. [PMID: 34295225 PMCID: PMC8290855 DOI: 10.3389/fnana.2021.715363] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Accepted: 05/28/2021] [Indexed: 01/16/2023] Open
Affiliation(s)
- Lena H Nguyen
- Department of Neurosurgery, Yale School of Medicine, Yale University, New Haven, CT, United States.,Department of Cellular & Molecular Physiology, Yale School of Medicine, Yale University, New Haven, CT, United States
| | - Angélique Bordey
- Department of Neurosurgery, Yale School of Medicine, Yale University, New Haven, CT, United States.,Department of Cellular & Molecular Physiology, Yale School of Medicine, Yale University, New Haven, CT, United States
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22
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Mizuguchi M, Ohsawa M, Kashii H, Sato A. Brain Symptoms of Tuberous Sclerosis Complex: Pathogenesis and Treatment. Int J Mol Sci 2021; 22:ijms22136677. [PMID: 34206526 PMCID: PMC8268912 DOI: 10.3390/ijms22136677] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 06/16/2021] [Accepted: 06/19/2021] [Indexed: 12/12/2022] Open
Abstract
The mammalian target of the rapamycin (mTOR) system plays multiple, important roles in the brain, regulating both morphology, such as cellular size, shape, and position, and function, such as learning, memory, and social interaction. Tuberous sclerosis complex (TSC) is a congenital disorder caused by a defective suppressor of the mTOR system, the TSC1/TSC2 complex. Almost all brain symptoms of TSC are manifestations of an excessive activity of the mTOR system. Many children with TSC are afflicted by intractable epilepsy, intellectual disability, and/or autism. In the brains of infants with TSC, a vicious cycle of epileptic encephalopathy is formed by mTOR hyperactivity, abnormal synaptic structure/function, and excessive epileptic discharges, further worsening epilepsy and intellectual/behavioral disorders. Molecular target therapy with mTOR inhibitors has recently been proved to be efficacious for epilepsy in human TSC patients, and for autism in TSC model mice, indicating the possibility for pharmacological treatment of developmental synaptic disorders.
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Affiliation(s)
- Masashi Mizuguchi
- Department of Developmental Medical Sciences, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan;
- Department of Pediatrics, National Rehabilitation Center for Children with Disabilities, Itabashi-ku, Tokyo 173-0037, Japan
- Correspondence: ; Tel.: +81-3-5841-3515
| | - Maki Ohsawa
- Department of Developmental Medical Sciences, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan;
- Department of Pediatrics, National Rehabilitation Center for Children with Disabilities, Itabashi-ku, Tokyo 173-0037, Japan
| | - Hirofumi Kashii
- Department of Neuropediatrics, Tokyo Metropolitan Neurological Hospital, Fuchu, Tokyo 183-0042, Japan;
| | - Atsushi Sato
- Department of Pediatrics, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo 113-8655, Japan;
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23
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Di Napoli C, Gennaro A, Lupica C, Falsaperla R, Leonardi R, Garozzo MT, Polizzi A, Praticò AD, Zanghì A, Ruggieri M. TSC1 and TSC2: Tuberous Sclerosis Complex and Its Related Epilepsy Phenotype. JOURNAL OF PEDIATRIC NEUROLOGY 2021. [DOI: 10.1055/s-0041-1727142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
AbstractTuberous sclerosis complex (TSC) is an autosomal dominant disorder characterized by a multisystemic involvement. In TSC, reduced function of TSC1 and TSC2 genes products (hamartin and tuberin, respectively) leads to an hyperactivation of the mechanistic target of rapamycin (mTOR) pathway and to a consequent cell growth dysregulation. In TSC patients, neurological and neuropsychiatric manifestations, especially epilepsy and neuropsychiatric comorbidities such as autism or intellectual disability, represent the most disabling features. In particular, epilepsy occurrs up to 80% of patients, is often drug resistant and is frequently associated with neurological impairment. Due to the burden of this morbidity, different treatment strategies have been proposed with the purpose to make patients epilepsy free, such as the use of different antiepileptic drugs like vigabatrin, carbamazepine, valproic acid, and levetiracetam. More recently, a mTOR inhibitor (i.e. everolimus) has showed promising results in terms of seizures reduction.
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Affiliation(s)
- Claudia Di Napoli
- Postgraduate Training Program in Genetics, Department of Biomedical and Biotechnological Sciences, Section of Genetics, University of Catania, Catania, Italy
| | - Alessia Gennaro
- Postgraduate Training Program in Genetics, Department of Biomedical and Biotechnological Sciences, Section of Genetics, University of Catania, Catania, Italy
| | - Carmelania Lupica
- Postgraduate Training Program in Genetics, Department of Biomedical and Biotechnological Sciences, Section of Genetics, University of Catania, Catania, Italy
| | - Raffaele Falsaperla
- Unit of Pediatrics and Pediatric Emergency, University Hospital “Policlinico Rodolico-San Marco,” Catania, Italy
- Unit of Neonatal Intenstive Care and Neonatology, University Hospital “Policlinico Rodolico-San Marco,” Catania, Italy
| | - Roberta Leonardi
- Department of Clinical and Experimental Medicine, Section of Pediatrics and Child Neuropsychiatry, Unit of Rare Diseases of the Nervous System in Childhood, University of Catania, Catania, Italy
| | - Maria Teresa Garozzo
- Unit of Pediatrics and Pediatric Emergency, Hospital “Cannizzaro,” Catania, Italy
| | - Agata Polizzi
- Chair of Pediatrics, Department of Educational Sciences, University of Catania, Catania, Italy
| | - Andrea D. Praticò
- Department of Clinical and Experimental Medicine, Section of Pediatrics and Child Neuropsychiatry, Unit of Rare Diseases of the Nervous System in Childhood, University of Catania, Catania, Italy
| | - Antonio Zanghì
- Department of General Surgery and Medical-Surgical Specialty, University of Catania, Catania, Italy
| | - Martino Ruggieri
- Chair of Pediatrics, Department of Educational Sciences, University of Catania, Catania, Italy
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Deng Y, Yang Q, Yang Y, Li Y, Peng H, Wu S, Zhang S, Yao B, Li S, Gao Y, Li X, Li L, Deng Y. Conditional knockout of Tsc1 in RORγt-expressing cells induces brain damage and early death in mice. J Neuroinflammation 2021; 18:107. [PMID: 33957945 PMCID: PMC8101034 DOI: 10.1186/s12974-021-02153-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Accepted: 04/15/2021] [Indexed: 11/23/2022] Open
Abstract
Background Tuberous sclerosis complex 1 (Tsc1) is known to regulate the development and function of various cell types, and RORγt is a critical transcription factor in the immune system. However, whether Tsc1 participates in regulating RORγt-expressing cells remains unknown. Methods We generated a mouse model in which Tsc1 was conditionally deleted from RORγt-expressing cells (Tsc1RORγt) to study the role of RORγt-expressing cells with Tsc1 deficiency in brain homeostasis. Results Type 3 innate lymphoid cells (ILC3s) in Tsc1RORγt mice displayed normal development and function, and the mice showed normal Th17 cell differentiation. However, Tsc1RORγt mice exhibited spontaneous tonic-clonic seizures and died between 4 and 6 weeks after birth. At the age of 4 weeks, mice in which Tsc1 was specifically knocked out in RORγt-expressing cells had cortical neuron defects and hippocampal structural abnormalities. Notably, over-activation of neurons and astrogliosis were observed in the cortex and hippocampus of Tsc1RORγt mice. Moreover, expression of the γ-amino butyric acid (GABA) receptor in the brains of Tsc1RORγt mice was decreased, and GABA supplementation prolonged the lifespan of the mice to some extent. Further experiments revealed the presence of a group of rare RORγt-expressing cells with high metabolic activity in the mouse brain. Conclusions Our study verifies the critical role of previously unnoticed RORγt-expressing cells in the brain and demonstrates that the Tsc1 signaling pathway in RORγt-expressing cells is important for maintaining brain homeostasis. Supplementary Information The online version contains supplementary material available at 10.1186/s12974-021-02153-8.
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Affiliation(s)
- Yafei Deng
- Hunan Children's Research Institute (HCRI), Hunan Children's Hospital, Changsha, 410000, China
| | - Qinglan Yang
- Hunan Children's Research Institute (HCRI), Hunan Children's Hospital, Changsha, 410000, China
| | - Yao Yang
- Institute of Materia Medica, College of Pharmacy, Army Medical University (Third Military Medical University), Chongqing, 400038, China
| | - Yana Li
- Hunan Children's Research Institute (HCRI), Hunan Children's Hospital, Changsha, 410000, China
| | - Hongyan Peng
- Hunan Children's Research Institute (HCRI), Hunan Children's Hospital, Changsha, 410000, China
| | - Shuting Wu
- Hunan Children's Research Institute (HCRI), Hunan Children's Hospital, Changsha, 410000, China
| | - Shuju Zhang
- Hunan Children's Research Institute (HCRI), Hunan Children's Hospital, Changsha, 410000, China
| | - Baige Yao
- Department of Pharmacy, The Third Xiangya Hospital, Central South University, Changsha, 410000, China
| | - Shuhui Li
- Department of Clinical Biochemistry, Faculty of Pharmacy and Laboratory Medicine, Army Medical University (Third Military Medical University), Chongqing, 400038, China
| | - Yuan Gao
- Southwest Hospital/Southwest Eye Hospital, Third Military Medical University, Chongqing, 400038, China
| | - Xiaohui Li
- Institute of Materia Medica, College of Pharmacy, Army Medical University (Third Military Medical University), Chongqing, 400038, China.
| | - Liping Li
- Hunan Children's Research Institute (HCRI), Hunan Children's Hospital, Changsha, 410000, China.
| | - Youcai Deng
- Institute of Materia Medica, College of Pharmacy, Army Medical University (Third Military Medical University), Chongqing, 400038, China.
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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: 35] [Impact Index Per Article: 11.7] [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.
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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
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26
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Nguyen LH, Bordey A. Convergent and Divergent Mechanisms of Epileptogenesis in mTORopathies. Front Neuroanat 2021; 15:664695. [PMID: 33897381 PMCID: PMC8064518 DOI: 10.3389/fnana.2021.664695] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Accepted: 03/17/2021] [Indexed: 12/30/2022] Open
Abstract
Hyperactivation of the mechanistic target of rapamycin complex 1 (mTORC1) due to mutations in genes along the PI3K-mTOR pathway and the GATOR1 complex causes a spectrum of neurodevelopmental disorders (termed mTORopathies) associated with malformation of cortical development and intractable epilepsy. Despite these gene variants’ converging impact on mTORC1 activity, emerging findings suggest that these variants contribute to epilepsy through both mTORC1-dependent and -independent mechanisms. Here, we review the literature on in utero electroporation-based animal models of mTORopathies, which recapitulate the brain mosaic pattern of mTORC1 hyperactivity, and compare the effects of distinct PI3K-mTOR pathway and GATOR1 complex gene variants on cortical development and epilepsy. We report the outcomes on cortical pyramidal neuronal placement, morphology, and electrophysiological phenotypes, and discuss some of the converging and diverging mechanisms responsible for these alterations and their contribution to epileptogenesis. We also discuss potential therapeutic strategies for epilepsy, beyond mTORC1 inhibition with rapamycin or everolimus, that could offer personalized medicine based on the gene variant.
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Affiliation(s)
- Lena H Nguyen
- Department of Neurosurgery, Yale School of Medicine, Yale University, New Haven, CT, United States.,Department of Cellular & Molecular Physiology, Yale School of Medicine, Yale University, New Haven, CT, United States
| | - Angélique Bordey
- Department of Neurosurgery, Yale School of Medicine, Yale University, New Haven, CT, United States.,Department of Cellular & Molecular Physiology, Yale School of Medicine, Yale University, New Haven, CT, United States
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27
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Kao HY, Hu S, Mihaylova T, Ziobro J, Ahn E, Fine C, Brang D, Watson BO, Wang Y. Defining the latent period of epileptogenesis and epileptogenic zone in a focal cortical dysplasia type II (FCDII) rat model. Epilepsia 2021; 62:1268-1279. [PMID: 33735460 PMCID: PMC8211029 DOI: 10.1111/epi.16868] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Revised: 02/21/2021] [Accepted: 02/22/2021] [Indexed: 12/14/2022]
Abstract
Objectives Focal cortical dysplasia type II (FCDII) is one of the most common underlying pathologies in patients with drug‐resistant epilepsy. However, mechanistic understanding of FCDII fails to keep pace with genetic discoveries, primarily due to the significant challenge in developing a clinically relevant animal model. Conceptually and clinically important questions, such as the unknown latent period of epileptogenesis and the controversial epileptogenic zone, remain unknown in all experimental FCDII animal models, making it even more challenging to investigate the underlying epileptogenic mechanisms. Methods In this study, we used continuous video‐electroencephalography (EEG) monitoring to detect the earliest interictal and ictal events in a clustered regularly interspaced short palindromic repeats (CRISPR)‐in utero electroporation (IUE) FCDII rat model that shares genetic, pathological, and electroclinical signatures with those observed in humans. We then took advantage of in vivo local field potential (LFP) recordings to localize the epileptogenic zone in these animals. Results To the best of our knowledge, we showed for the first time that epileptiform discharges emerged during the third postnatal week, and that the first seizure occurred as early as during the fourth postnatal week. We also showed that both interictal and ictal discharges are localized within the dysplastic cortex, concordant with human clinical data. Significance Together, our work identified the temporal and spatial frame of epileptogenesis in a highly clinically relevant FCDII animal model, paving the way for mechanistic studies at molecular, cellular, and circuitry levels.
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Affiliation(s)
- Hsin-Yi Kao
- Department of Neurology, University of Michigan, Ann Arbor, USA
| | - Shuntong Hu
- Department of Neurology, University of Michigan, Ann Arbor, USA.,Department of Neurology, the Third Xiangya Hospital, Central South University, Changsha, China
| | | | - Julie Ziobro
- Department of Pediatrics, University of Michigan, Ann Arbor, USA
| | - EunSeon Ahn
- Department of Psychology, University of Michigan, Ann Arbor, USA
| | - Carli Fine
- Department of Psychology, University of Michigan, Ann Arbor, USA
| | - David Brang
- Department of Psychology, University of Michigan, Ann Arbor, USA
| | - Brendon O Watson
- Department of Psychiatry, University of Michigan, Ann Arbor, USA.,Molecular and Behavioral Neuroscience Institute, University of Michigan, Ann Arbor, USA
| | - Yu Wang
- Department of Neurology, University of Michigan, Ann Arbor, USA
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28
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Hsieh LS, Wen JH, Nguyen LH, Zhang L, Getz S, Torres-Reveron J, Wang Y, Spencer DD, Bordey A. Ectopic HCN4 expression drives mTOR-dependent epilepsy in mice. Sci Transl Med 2020; 12:12/570/eabc1492. [PMID: 33208499 PMCID: PMC9888000 DOI: 10.1126/scitranslmed.abc1492] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Accepted: 07/31/2020] [Indexed: 02/03/2023]
Abstract
The causative link between focal cortical malformations (FCMs) and epilepsy is well accepted, especially among patients with focal cortical dysplasia type II (FCDII) and tuberous sclerosis complex (TSC). However, the mechanisms underlying seizures remain unclear. Using a mouse model of TSC- and FCDII-associated FCM, we showed that FCM neurons were responsible for seizure activity via their unexpected abnormal expression of the hyperpolarization-activated cyclic nucleotide-gated potassium channel isoform 4 (HCN4), which is normally not present in cortical pyramidal neurons after birth. Increasing intracellular cAMP concentrations, which preferentially affects HCN4 gating relative to the other isoforms, drove repetitive firing of FCM neurons but not control pyramidal neurons. Ectopic HCN4 expression was dependent on the mechanistic target of rapamycin (mTOR), preceded the onset of seizures, and was also found in diseased neurons in tissue resected from patients with TSC and FCDII. Last, blocking HCN4 channel activity in FCM neurons prevented epilepsy in the mouse model. These findings suggest that HCN4 play a main role in seizure and identify a cAMP-dependent seizure mechanism in TSC and FCDII. Furthermore, the unique expression of HCN4 exclusively in FCM neurons suggests that gene therapy targeting HCN4 might be effective in reducing seizures in FCDII or TSC.
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Affiliation(s)
- Lawrence S. Hsieh
- Department of Neurosurgery, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA
| | - John H. Wen
- Department of Neurosurgery, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA
| | - Lena H. Nguyen
- Department of Neurosurgery, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA
| | - Longbo Zhang
- Department of Neurosurgery, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA
| | - Stephanie Getz
- Department of Neurosurgery, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA
| | - Juan Torres-Reveron
- Department of Neurosurgery, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA
| | - Ying Wang
- Emergency Department, Xiangya Hospital, Central South University, 87 Xiangya Street, Changsha, Hunan 410008, China
| | - Dennis D. Spencer
- Department of Neurosurgery, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA
| | - Angélique Bordey
- Department of Neurosurgery, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA,Department of Cellular & Molecular Physiology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA,To whom correspondence should be addressed: Angélique Bordey, Ph.D., Department of Neurosurgery, Yale University School of Medicine, 333 Cedar Street, FMB 422, New Haven, CT 06520-8082, Phone: 203-737-2515, Fax: 203-737-2159,
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29
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Lin J, Fang Y, Zhang M, Wang X, Li L, He M, Xue A, Zhu K, Shen Y, Li B. Phosphorylation of PRAS40 contributes to the activation of the PI3K/AKT/mTOR signaling pathway and the inhibition of autophagy following status epilepticus in rats. Exp Ther Med 2020; 20:3625-3632. [PMID: 32855714 PMCID: PMC7444373 DOI: 10.3892/etm.2020.9085] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2018] [Accepted: 06/02/2020] [Indexed: 12/30/2022] Open
Abstract
Status epilepticus (SE) is a neurological disorder associated with high morbidity and mortality rates, and is often difficult to treat. Moreover, the underlying mechanism of SE remains unknown. The lithium-pilocarpine model is a validated animal model that can reproduce the main clinical and neuropathological features of SE. In the present study, this SE model was utilized and SE was successfully established in rats, as determined by the corresponding epileptic electroencephalogram. Histology, immunohistochemistry, western blot analysis and co-immunoprecipitation were used to detect the phosphorylation (p-) of AKT substrate of 40 kDa (PRAS40), the combination of p-PRAS40 and 14-3-3 protein and the activation of the PI3K/mTOR signaling pathway in SE. In addition, the present study analyzed the dynamics of the expression of autophagy-associated factors in the hippocampus after SE induction, and the influence of suppressing the p- of PRAS40 on the autophagy process was detected in the pathogenesis of SE. The results indicated that increased p-PRAS40 expression could activate the mTOR pathway to decrease the level of autophagy. However, inhibition of the mTOR signaling pathway promoted autophagy flux. These results may provide further understanding of p-PRAS40 functions in SE.
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Affiliation(s)
- Junyi Lin
- School of Policing Studies, Shanghai University of Political Science and Law, Shanghai 201701, P.R. China.,Department of Forensic Medicine, School of Basic Medical Sciences, Fudan University, Shanghai 200032, P.R. China
| | - Youxin Fang
- General Family Medicine Clinic, Xuhui District Xietu Subdistrict Community Healthcare Center, Shanghai 200120, P.R. China
| | - Mingchang Zhang
- Department of Forensic Medicine, School of Basic Medical Sciences, Fudan University, Shanghai 200032, P.R. China
| | - Xiang Wang
- Institute of Forensic Science, Jiading Branch of Shanghai Public Security Bureau, Shanghai 201800, P.R. China
| | - Liliang Li
- Department of Forensic Medicine, School of Basic Medical Sciences, Fudan University, Shanghai 200032, P.R. China
| | - Meng He
- Department of Forensic Medicine, School of Basic Medical Sciences, Fudan University, Shanghai 200032, P.R. China
| | - Aimin Xue
- Department of Forensic Medicine, School of Basic Medical Sciences, Fudan University, Shanghai 200032, P.R. China
| | - Keming Zhu
- Department of Anatomy, Histology and Embryology, School of Basic Medical Sciences, Fudan University, Shanghai 200032, P.R. China
| | - Yiwen Shen
- Department of Forensic Medicine, School of Basic Medical Sciences, Fudan University, Shanghai 200032, P.R. China
| | - Beixu Li
- School of Policing Studies, Shanghai University of Political Science and Law, Shanghai 201701, P.R. China.,Department of Forensic Medicine, School of Basic Medical Sciences, Fudan University, Shanghai 200032, P.R. China
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30
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Microglial mTOR is Neuronal Protective and Antiepileptogenic in the Pilocarpine Model of Temporal Lobe Epilepsy. J Neurosci 2020; 40:7593-7608. [PMID: 32868461 DOI: 10.1523/jneurosci.2754-19.2020] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 08/05/2020] [Accepted: 08/24/2020] [Indexed: 01/01/2023] Open
Abstract
Excessive activation of mammalian target of rapamycin (mTOR) signaling is epileptogenic in genetic epilepsy. However, the exact role of microglial mTOR in acquired epilepsy remains to be clarified. In the present study, we found that mTOR is strongly activated in microglia following excitatory injury elicited by status epilepticus. To determine the role of microglial mTOR signaling in excitatory injury and epileptogenesis, we generated mice with restrictive deletion of mTOR in microglia. Both male and female mice were used in the present study. We found that mTOR-deficient microglia lost their typical proliferative and inflammatory responses to excitatory injury, whereas the proliferation of astrocytes was preserved. In addition, mTOR-deficient microglia did not effectively engulf injured/dying neurons. More importantly, microglial mTOR-deficient mice displayed increased neuronal loss and developed more severe spontaneous seizures. These findings suggest that microglial mTOR plays a protective role in mitigating neuronal loss and attenuating epileptogenesis in the excitatory injury model of epilepsy.SIGNIFICANCE STATEMENT The mammalian target of rapamycin (mTOR) pathway is strongly implicated in epilepsy. However, the effect of mTOR inhibitors in preclinical models of acquired epilepsy is inconsistent. The broad presence of mTOR signaling in various brain cells could prevent mTOR inhibitors from achieving a net therapeutic effect. This conundrum has spurred further investigation of the cell type-specific effects of mTOR signaling in the CNS. We found that activation of microglial mTOR is antiepileptogenic. Thus, microglial mTOR activation represents a novel antiepileptogenic route that appears to parallel the proepileptogenic route of neuronal mTOR activation. This may explain why the net effect of mTOR inhibitors is paradoxical in the acquired models of epilepsy. Our findings could better guide the use of mTOR inhibitors in preventing acquired epilepsy.
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31
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Key J, Harter PN, Sen NE, Gradhand E, Auburger G, Gispert S. Mid-Gestation lethality of Atxn2l-Ablated Mice. Int J Mol Sci 2020; 21:E5124. [PMID: 32698485 PMCID: PMC7404131 DOI: 10.3390/ijms21145124] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Revised: 07/10/2020] [Accepted: 07/16/2020] [Indexed: 12/11/2022] Open
Abstract
Depletion of yeast/fly Ataxin-2 rescues TDP-43 overexpression toxicity. In mouse models of Amyotrophic Lateral Sclerosis via TDP-43 overexpression, depletion of its ortholog ATXN2 mitigated motor neuron degeneration and extended lifespan from 25 days to >300 days. There is another ortholog in mammals, named ATXN2L (Ataxin-2-like), which is almost uncharacterized but also functions in RNA surveillance at stress granules. We generated mice with Crispr/Cas9-mediated deletion of Atxn2l exons 5-8, studying homozygotes prenatally and heterozygotes during aging. Our novel findings indicate that ATXN2L absence triggers mid-gestational embryonic lethality, affecting female animals more strongly. Weight and development stages of homozygous mutants were reduced. Placenta phenotypes were not apparent, but brain histology showed lamination defects and apoptosis. Aged heterozygotes showed no locomotor deficits or weight loss over 12 months. Null mutants in vivo displayed compensatory efforts to maximize Atxn2l expression, which were prevented upon nutrient abundance in vitro. Mouse embryonal fibroblast cells revealed more multinucleated giant cells upon ATXN2L deficiency. In addition, in human neural cells, transcript levels of ATXN2L were induced upon starvation and glucose and amino acids exposure, but this induction was partially prevented by serum or low cholesterol administration. Neither ATXN2L depletion triggered dysregulation of ATXN2, nor a converse effect was observed. Overall, this essential role of ATXN2L for embryogenesis raises questions about its role in neurodegenerative diseases and neuroprotective therapies.
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Affiliation(s)
- Jana Key
- Exp. Neurology, Medical Faculty, Goethe University, Theodor Stern Kai 7, 60590 Frankfurt am Main, Germany; (J.K.); (N.-E.S.)
- Faculty of Biosciences, Goethe-University, Altenhöferallee 1, 60438 Frankfurt am Main, Germany
| | - Patrick N. Harter
- Institute of Neurology (Edinger-Institute), University Hospital Frankfurt, Goethe University, Heinrich-Hoffmann-Strasse 7, 60528 Frankfurt am Main, Germany;
| | - Nesli-Ece Sen
- Exp. Neurology, Medical Faculty, Goethe University, Theodor Stern Kai 7, 60590 Frankfurt am Main, Germany; (J.K.); (N.-E.S.)
- Faculty of Biosciences, Goethe-University, Altenhöferallee 1, 60438 Frankfurt am Main, Germany
| | - Elise Gradhand
- Dr. Senckenberg Institute for Pathology, University Hospital, Goethe University, Theodor-Stern-Kai-7, 60590 Frankfurt am Main, Germany;
| | - Georg Auburger
- Exp. Neurology, Medical Faculty, Goethe University, Theodor Stern Kai 7, 60590 Frankfurt am Main, Germany; (J.K.); (N.-E.S.)
| | - Suzana Gispert
- Exp. Neurology, Medical Faculty, Goethe University, Theodor Stern Kai 7, 60590 Frankfurt am Main, Germany; (J.K.); (N.-E.S.)
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32
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Feliciano DM. The Neurodevelopmental Pathogenesis of Tuberous Sclerosis Complex (TSC). Front Neuroanat 2020; 14:39. [PMID: 32765227 PMCID: PMC7381175 DOI: 10.3389/fnana.2020.00039] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2020] [Accepted: 06/10/2020] [Indexed: 12/22/2022] Open
Abstract
Tuberous sclerosis complex (TSC) is a model disorder for understanding brain development because the genes that cause TSC are known, many downstream molecular pathways have been identified, and the resulting perturbations of cellular events are established. TSC, therefore, provides an intellectual framework to understand the molecular and biochemical pathways that orchestrate normal brain development. The TSC1 and TSC2 genes encode Hamartin and Tuberin which form a GTPase activating protein (GAP) complex. Inactivating mutations in TSC genes (TSC1/TSC2) cause sustained Ras homologue enriched in brain (RHEB) activation of the mammalian isoform of the target of rapamycin complex 1 (mTORC1). TOR is a protein kinase that regulates cell size in many organisms throughout nature. mTORC1 inhibits catabolic processes including autophagy and activates anabolic processes including mRNA translation. mTORC1 regulation is achieved through two main upstream mechanisms. The first mechanism is regulation by growth factor signaling. The second mechanism is regulation by amino acids. Gene mutations that cause too much or too little mTORC1 activity lead to a spectrum of neuroanatomical changes ranging from altered brain size (micro and macrocephaly) to cortical malformations to Type I neoplasias. Because somatic mutations often underlie these changes, the timing, and location of mutation results in focal brain malformations. These mutations, therefore, provide gain-of-function and loss-of-function changes that are a powerful tool to assess the events that have gone awry during development and to determine their functional physiological consequences. Knowledge about the TSC-mTORC1 pathway has allowed scientists to predict which upstream and downstream mutations should cause commensurate neuroanatomical changes. Indeed, many of these predictions have now been clinically validated. A description of clinical imaging and histochemical findings is provided in relation to laboratory models of TSC that will allow the reader to appreciate how human pathology can provide an understanding of the fundamental mechanisms of development.
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Affiliation(s)
- David M Feliciano
- Department of Biological Sciences, Clemson University, Clemson, SC, United States
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33
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Zhang DY, Song H, Ming GL. Modeling neurological disorders using brain organoids. Semin Cell Dev Biol 2020; 111:4-14. [PMID: 32561297 DOI: 10.1016/j.semcdb.2020.05.026] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Revised: 05/08/2020] [Accepted: 05/27/2020] [Indexed: 12/18/2022]
Abstract
Neurological disorders are challenging to study given the complexity and species-specific features of the organ system. Brain organoids are three dimensional structured aggregates of neural tissue that are generated by self-organization and differentiation from pluripotent stem cells under optimized culture conditions. These brain organoids exhibit similar features of structural organization and cell type diversity as the developing human brain, creating opportunities to recapitulate disease phenotypes that are not otherwise accessible. Here we review the initial attempt in the field to apply brain organoid models for the study of many different types of human neurological disorders across a wide range of etiologies and pathophysiologies. Forthcoming advancements in both brain organoid technology as well as analytical methods have significant potentials to advance the understanding of neurological disorders and to uncover opportunities for meaningful therapeutic intervention.
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Affiliation(s)
- Daniel Y Zhang
- Biochemistry and Molecular Biophysics Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Hongjun Song
- Department of Neuroscience and Mahoney Institute for Neurosciences, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA; Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA; Institute for Regenerative Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA; The Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Guo-Li Ming
- Department of Neuroscience and Mahoney Institute for Neurosciences, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA; Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA; Institute for Regenerative Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA; Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA.
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34
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Rensing N, Johnson KJ, Foutz TJ, Friedman JL, Galindo R, Wong M. Early developmental electroencephalography abnormalities, neonatal seizures, and induced spasms in a mouse model of tuberous sclerosis complex. Epilepsia 2020; 61:879-891. [PMID: 32274803 DOI: 10.1111/epi.16495] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Revised: 03/10/2020] [Accepted: 03/11/2020] [Indexed: 11/30/2022]
Abstract
OBJECTIVE Tuberous sclerosis complex (TSC) is one of the most common genetic causes of epilepsy. Seizures in TSC typically first present in infancy or early childhood, including focal seizures and infantile spasms. Infantile spasms in TSC are particularly characteristic in its strong responsiveness to vigabatrin. Although a number of mouse models of epilepsy in TSC have been described, there are very limited electroencephalographic (EEG) or seizure data during the preweanling neonatal and infantile-equivalent mouse periods. Tsc1GFAP CKO mice are a well-characterized mouse model of epilepsy in TSC, but whether these mice have seizures during early development has not been documented. The objective of this study was to determine whether preweanling Tsc1GFAP CKO mice have developmental EEG abnormalities or seizures, including spasms. METHODS Longitudinal video-EEG and electromyographic recordings were performed serially on Tsc1GFAP CKO and control mice from postnatal days 9-21 and analyzed for EEG background abnormalities, sleep-wake vigilance states, and spontaneous seizures. Spasms were also induced with varying doses of N-methyl-D-aspartate (NMDA). RESULTS The interictal EEG of Tsc1GFAP CKO mice had excessive discontinuity and slowing, suggesting a delayed developmental progression compared with control mice. Tsc1GFAP CKO mice also had increased vigilance state transitions and fragmentation. Tsc1GFAP CKO mice had spontaneous focal seizures in the early neonatal period and a reduced threshold for NMDA-induced spasms, but no spontaneous spasms were observed. SIGNIFICANCE Neonatal Tsc1GFAP CKO mice recapitulate early developmental aspects of EEG abnormalities, focal seizures, and an increased propensity for spasms. This mouse model may be useful for early mechanistic and therapeutic studies of epileptogenesis in TSC.
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Affiliation(s)
- Nicholas Rensing
- Department of Neurology and Hope Center for Neurological Disorders, Washington University School of Medicine, St Louis, Missouri
| | - Kevin J Johnson
- Department of Neurology and Hope Center for Neurological Disorders, Washington University School of Medicine, St Louis, Missouri
| | - Thomas J Foutz
- Department of Neurology and Hope Center for Neurological Disorders, Washington University School of Medicine, St Louis, Missouri
| | - Joseph L Friedman
- Department of Neurology and Hope Center for Neurological Disorders, Washington University School of Medicine, St Louis, Missouri
| | - Rafael Galindo
- Department of Neurology and Hope Center for Neurological Disorders, Washington University School of Medicine, St Louis, Missouri
| | - Michael Wong
- Department of Neurology and Hope Center for Neurological Disorders, Washington University School of Medicine, St Louis, Missouri
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35
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Tarkowski B, Kuchcinska K, Blazejczyk M, Jaworski J. Pathological mTOR mutations impact cortical development. Hum Mol Genet 2020; 28:2107-2119. [PMID: 30789219 DOI: 10.1093/hmg/ddz042] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Revised: 02/08/2019] [Accepted: 02/11/2019] [Indexed: 02/03/2023] Open
Abstract
Several mosaic mutations of the mammalian/mechanistic target of rapamycin (mTOR) have recently been found in patients with cortical malformations, such as hemimegalencephaly (HME) and focal cortical dysplasia (FCD). Although all of them should activate mTOR signaling, comparisons of the impact of different mTOR mutations on brain development have been lacking. Also it remains unknown if any potential differences these mutations may have on cortical development are directly related to a degree of mTOR signaling increase. The present study assessed levels of mTORC1 pathway activity in cell lines and rat primary neurons overexpressing several mTOR mutants that were previously found in HME, FCD, cancer patients and in vitro mutagenesis screens. Next we introduced the mutants, enhancing mTORC1 signaling most potently, into developing mouse brains and assessed electroporated cell morphology and migratory phenotype using immunofluorescent staining. We observed the differential inhibition of neuronal progenitor cortical migration, which partly corresponded with a degree of mTORC1 signaling enhancement these mutants induced in cultured cells. The most potent quadruple mutant prevented most of the progenitors from entering the cortical plate. Cells that expressed less potent, single-point, mTOR mutants entered the cortical plate but failed to reach its upper layers and had enlarged soma. Our findings suggest a correlation between the potency of mTOR mutation to activate mTORC1 pathway and disruption of cortical migration.
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Affiliation(s)
- Bartosz Tarkowski
- International Institute of Molecular and Cell Biology, Warsaw, Poland
| | - Kinga Kuchcinska
- International Institute of Molecular and Cell Biology, Warsaw, Poland
| | | | - Jacek Jaworski
- International Institute of Molecular and Cell Biology, Warsaw, Poland
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36
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Ganesan H, Balasubramanian V, Iyer M, Venugopal A, Subramaniam MD, Cho SG, Vellingiri B. mTOR signalling pathway - A root cause for idiopathic autism? BMB Rep 2020. [PMID: 31186084 PMCID: PMC6675248 DOI: 10.5483/bmbrep.2019.52.7.137] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Autism spectrum disorder (ASD) is a complex neurodevelopmental monogenic disorder with a strong genetic influence. Idiopathic autism could be defined as a type of autism that does not have a specific causative agent. Among signalling cascades, mTOR signalling pathway plays a pivotal role not only in cell cycle, but also in protein synthesis and regulation of brain homeostasis in ASD patients. The present review highlights, underlying mechanism of mTOR and its role in altered signalling cascades as a triggering factor in the onset of idiopathic autism. Further, this review discusses how distorted mTOR signalling pathway stimulates truncated translation in neuronal cells and leads to downregulation of protein synthesis at dendritic spines of the brain. This review concludes by suggesting downstream regulators such as p70S6K, eIF4B, eIF4E of mTOR signalling pathway as promising therapeutic targets for idiopathic autistic individuals. [BMB Reports 2019; 52(7): 424-433].
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Affiliation(s)
- Harsha Ganesan
- Human Molecular Cytogenetics and Stem Cell Laboratory, Department of Human Genetics and Molecular Biology, Bharathiar University, Coimbatore 641046, Tamil Nadu, India
| | - Venkatesh Balasubramanian
- Human Molecular Cytogenetics and Stem Cell Laboratory, Department of Human Genetics and Molecular Biology, Bharathiar University, Coimbatore 641046, Tamil Nadu, India
| | - Mahalaxmi Iyer
- Department of Zoology, Avinashilingam Institute for Home Science and Higher Education for Women, Coimbatore 641043, Tamil Nadu, India
| | - Anila Venugopal
- Human Molecular Cytogenetics and Stem Cell Laboratory, Department of Human Genetics and Molecular Biology, Bharathiar University, Coimbatore 641046, Tamil Nadu, India
| | - Mohana Devi Subramaniam
- Department of Genetics and Molecular Biology, Vision Research Foundation, Sankara Nethralaya, Chennai 600006, Tamil Nadu, India
| | - Ssang-Goo Cho
- Department of Stem Cell and Regenerative Biotechnology, Konkuk University, Seoul 05029, Korea
| | - Balachandar Vellingiri
- Human Molecular Cytogenetics and Stem Cell Laboratory, Department of Human Genetics and Molecular Biology, Bharathiar University, Coimbatore 641046, Tamil Nadu, India
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37
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TrkB hyperactivity contributes to brain dysconnectivity, epileptogenesis, and anxiety in zebrafish model of Tuberous Sclerosis Complex. Proc Natl Acad Sci U S A 2020; 117:2170-2179. [PMID: 31932427 PMCID: PMC6995026 DOI: 10.1073/pnas.1910834117] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Tuberous Sclerosis Complex (TSC) is a rare genetic disease that manifests with early symptoms, including cortical malformations, childhood epilepsy, and TSC-associated neuropsychiatric disorders (TANDs). Cortical malformations arise during embryonic development and have been linked to childhood epilepsy before, but the underlying mechanisms of this relationship remain insufficiently understood. Zebrafish have emerged as a convenient model to study elementary neurodevelopment; however, without in-depth functional analysis, the Tsc2-deficient zebrafish line cannot be used for studies of TANDs or new drug screening. In this study, we found that the lack of Tsc2 in zebrafish resulted in heterotopias and hyperactivation of the mTorC1 pathway in pallial regions, which are homologous to the mammalian cortex. We observed commissural thinning that was responsible for brain dysconnectivity, recapitulating TSC pathology in human patients. The lack of Tsc2 also delayed axonal development and caused aberrant tract fasciculation, corresponding to the abnormal expression of genes involved in axon navigation. The mutants underwent epileptogenesis that resulted in nonmotor seizures and exhibited increased anxiety-like behavior. We further mapped discrete parameters of locomotor activity to epilepsy-like and anxiety-like behaviors, which were rescued by reducing tyrosine receptor kinase B (TrkB) signaling. Moreover, in contrast to treatment with vigabatrin and rapamycin, TrkB inhibition rescued brain dysconnectivity and anxiety-like behavior. These data reveal that commissural thinning results in the aberrant regulation of anxiety, providing a mechanistic link between brain anatomy and human TANDs. Our findings also implicate TrkB signaling in the complex pathology of TSC and reveal a therapeutic target.
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38
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Sceniak MP, Fedder KN, Wang Q, Droubi S, Babcock K, Patwardhan S, Wright-Zornes J, Pham L, Sabo SL. An autism-associated mutation in GluN2B prevents NMDA receptor trafficking and interferes with dendrite growth. J Cell Sci 2019; 132:jcs.232892. [PMID: 31548203 DOI: 10.1242/jcs.232892] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Accepted: 09/16/2019] [Indexed: 12/15/2022] Open
Abstract
Autism spectrum disorders (ASDs) are neurodevelopmental disorders with multiple genetic associations. Analysis of de novo mutations identified GRIN2B, which encodes the GluN2B subunit of NMDA receptors, as a gene linked to ASDs with high probability. However, the mechanisms by which GRIN2B mutations contribute to ASD pathophysiology are not understood. Here, we investigated the cellular phenotypes induced by a human mutation that is predicted to truncate GluN2B within the extracellular loop. This mutation abolished NMDA-dependent Ca2+ influx. Mutant GluN2B co-assembled with GluN1 but was not trafficked to the cell surface or dendrites. When mutant GluN2B was expressed in developing cortical neurons, dendrites appeared underdeveloped, with shorter and fewer branches, while spine density was unaffected. Mutant dendritic arbors were often dysmorphic, displaying abnormal filopodial-like structures. Interestingly, dendrite maldevelopment appeared when mutant GluN2B was expressed on a wild-type background, reflecting the disease given that individuals are heterozygous for GRIN2B mutations. Restoring the fourth transmembrane domain and cytoplasmic tail did not rescue the phenotypes. Finally, abnormal development was not accompanied by reduced mTOR signaling. These data suggest that mutations in GluN2B contribute to ASD pathogenesis by disrupting dendrite development.
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Affiliation(s)
- Michael P Sceniak
- Department of Biology, Central Michigan University, Mount Pleasant, MI 48859, USA
| | - Karlie N Fedder
- Departments of Pharmacology and Neuroscience, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Qian Wang
- Department of Biology, Central Michigan University, Mount Pleasant, MI 48859, USA
| | - Sammy Droubi
- Departments of Pharmacology and Neuroscience, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Katie Babcock
- Department of Biology, Central Michigan University, Mount Pleasant, MI 48859, USA
| | - Sagar Patwardhan
- Departments of Pharmacology and Neuroscience, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Jazmin Wright-Zornes
- Department of Biology, Central Michigan University, Mount Pleasant, MI 48859, USA
| | - Lucynda Pham
- Department of Biology, Central Michigan University, Mount Pleasant, MI 48859, USA
| | - Shasta L Sabo
- Department of Biology, Central Michigan University, Mount Pleasant, MI 48859, USA .,Departments of Pharmacology and Neuroscience, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
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39
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Morton MC, Neckles VN, Seluzicki CM, Holmberg JC, Feliciano DM. Neonatal Subventricular Zone Neural Stem Cells Release Extracellular Vesicles that Act as a Microglial Morphogen. Cell Rep 2019; 23:78-89. [PMID: 29617675 DOI: 10.1016/j.celrep.2018.03.037] [Citation(s) in RCA: 84] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Revised: 02/19/2018] [Accepted: 03/09/2018] [Indexed: 02/06/2023] Open
Abstract
Subventricular zone (SVZ) neural stem cells (NSCs) are the cornerstone of the perinatal neurogenic niche. Microglia are immune cells of the nervous system that are enriched in the neonatal SVZ. Although microglia regulate NSCs, the extent to which this interaction is bi-directional is unclear. Extracellular vesicles (EVs) are cell-derived particles that encase miRNA and proteins. Here, we demonstrate that SVZ NSCs generate and release EVs. Neonatal electroporated fluorescent EV fusion proteins were released by NSCs and subsequently cleared from the SVZ. EVs were preferentially targeted to microglia. Small RNA sequencing identified miRNAs within the EVs that regulate microglia physiology and morphology. EVs induced a transition to a CD11b/Iba1 non-stellate microglial morphology. The transition accompanied a microglial transcriptional state characterized by Let-7-regulated cytokine release and a negative feedback loop that controlled NSC proliferation. These findings implicate an NSC-EV-microglia axis and provide insight to normal and pathophysiological brain development.
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Affiliation(s)
- Mary C Morton
- Department of Biological Sciences, Clemson University, Clemson, SC 29634-0314, USA
| | - Victoria N Neckles
- Department of Biological Sciences, Clemson University, Clemson, SC 29634-0314, USA
| | - Caitlin M Seluzicki
- Department of Biological Sciences, Clemson University, Clemson, SC 29634-0314, USA
| | - Jennie C Holmberg
- Department of Biological Sciences, Clemson University, Clemson, SC 29634-0314, USA
| | - David M Feliciano
- Department of Biological Sciences, Clemson University, Clemson, SC 29634-0314, USA.
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40
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Zhang L, Huang T, Teaw S, Bordey A. Hypervascularization in mTOR-dependent focal and global cortical malformations displays differential rapamycin sensitivity. Epilepsia 2019; 60:1255-1265. [PMID: 31125447 DOI: 10.1111/epi.15969] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Revised: 04/26/2019] [Accepted: 04/26/2019] [Indexed: 01/16/2023]
Abstract
OBJECTIVES Patients with mammalian target of rapamycin (mTOR)-dependent malformations of cortical development (MCDs) associated with seizures display hyperperfusion and increased vessel density of the dysmorphic cortical tissue. Some studies have suggested that the vascular defect occurred independently of seizures. Here, we further examined whether hypervascularization occurs in animal models of global and focal MCD with and without seizures, and whether it is sensitive to the mTOR blocker, rapamycin, that is approved for epilepsy treatment in tuberous sclerosis complex. METHODS We used two experimental models of mTOR-dependent MCD consisting of conditional transgenic mice containing Tsc1null cells in the forebrain generating a global malformation associated with seizures and of wild-type mice containing a focal malformation in the somatosensory cortex generated by in utero electroporation (IUE) that does not lead to seizures. Alterations in blood vessels and the effects of a 2-week-long rapamycin treatment on these phenotypes were assessed in juvenile mice. RESULTS Blood vessels in both the focal and global MCDs of postnatal day 14 mice displayed significant increase in vessel density, branching index, total vessel length, and decreased tissue lacunarity. In addition, rapamycin treatment (0.5 mg/kg, every 2 days) partially rescued vessel abnormalities in the focal MCD model, but it did not ameliorate the vessel abnormalities in the global MCD model that required higher rapamycin dosage for a partial rescue. SIGNIFICANCE Here, we identified hypervascularization in mTOR-dependent MCD in the absence of seizures in young mice, suggesting that increased angiogenesis occurs during development in parallel to alterations in corticogenesis. In addition, a predictive functional outcome is that dysplastic neurons forming MCD will have better access to oxygen and metabolic supplies via their closer proximity to blood vessels. Finally, the difference in rapamycin sensitivity between a focal and global MCD suggest that rapamycin treatment will need to be titrated to match the type of MCD.
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Affiliation(s)
- Longbo Zhang
- Department of Neurosurgery, Xiangya Hospital, Central South University, Changsha, China
- Departments of Neurosurgery and Cellular & Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut
| | - Tianxiang Huang
- Department of Neurosurgery, Xiangya Hospital, Central South University, Changsha, China
- Departments of Neurosurgery and Cellular & Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut
| | - Shannon Teaw
- Departments of Neurosurgery and Cellular & Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut
| | - Angélique Bordey
- Departments of Neurosurgery and Cellular & Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut
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41
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Salussolia CL, Klonowska K, Kwiatkowski DJ, Sahin M. Genetic Etiologies, Diagnosis, and Treatment of Tuberous Sclerosis Complex. Annu Rev Genomics Hum Genet 2019; 20:217-240. [PMID: 31018109 DOI: 10.1146/annurev-genom-083118-015354] [Citation(s) in RCA: 93] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Tuberous sclerosis complex (TSC) is an autosomal dominant disorder that affects multiple organ systems due to an inactivating variant in either TSC1 or TSC2, resulting in the hyperactivation of the mechanistic target of rapamycin (mTOR) pathway. Dysregulated mTOR signaling results in increased cell growth and proliferation. Clinically, TSC patients exhibit great phenotypic variability, but the neurologic and neuropsychiatric manifestations of the disease have the greatest morbidity and mortality. TSC-associated epilepsy occurs in nearly all patients and is often difficult to treat because it is refractory to multiple antiseizure medications. The advent of mTOR inhibitors offers great promise in the treatment of TSC-associated epilepsy and other neurodevelopmental manifestations of the disease; however, the optimal timing of therapeutic intervention is not yet fully understood.
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Affiliation(s)
- Catherine L Salussolia
- F.M. Kirby Neurobiology Center, Translational Neuroscience Center, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA;
| | - Katarzyna Klonowska
- Division of Pulmonary and Critical Care Medicine and Division of Genetics, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts 02115, USA
| | - David J Kwiatkowski
- Division of Pulmonary and Critical Care Medicine and Division of Genetics, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Mustafa Sahin
- F.M. Kirby Neurobiology Center, Translational Neuroscience Center, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA;
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42
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Nguyen LH, Mahadeo T, Bordey A. mTOR Hyperactivity Levels Influence the Severity of Epilepsy and Associated Neuropathology in an Experimental Model of Tuberous Sclerosis Complex and Focal Cortical Dysplasia. J Neurosci 2019; 39:2762-2773. [PMID: 30700531 PMCID: PMC6445990 DOI: 10.1523/jneurosci.2260-18.2019] [Citation(s) in RCA: 73] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2018] [Revised: 01/14/2019] [Accepted: 01/15/2019] [Indexed: 01/28/2023] Open
Abstract
Tuberous sclerosis complex (TSC) and focal cortical dysplasia (FCD) are focal malformations of cortical development (FMCDs) that are highly associated with intractable epilepsy. TSC and FCD are mTORopathies caused by a spectrum of pathogenic variants in the mechanistic target of rapamycin (mTOR) pathway genes leading to differential activation of mTOR signaling. However, whether the degree of mTOR hyperactivity influences disease severity remains unclear. Here, we examined the effects of differential mTOR hyperactivity levels on epilepsy and associated neuropathology in a mouse model of TSC and FCD. Constitutively active Rheb (RhebCA), the canonical activator of mTOR complex 1 (mTORC1), was expressed in mouse embryos of either sex via in utero electroporation at low, intermediate, and high concentrations to induce different mTORC1 activity levels in developing cortical neurons. We found that RhebCA expression induced mTORC1 hyperactivation and increased neuronal soma size and misplacement in a dose-dependent manner. No seizures were detected in the low RhebCA mice, whereas the intermediate and high RhebCA mice displayed spontaneous, recurrent seizures that significantly increased with higher RhebCA concentrations. Seizures were associated with a global increase in microglial activation that was notably higher in the regions containing RhebCA-expressing neurons. These data demonstrate that neuronal mTOR hyperactivity levels influence the severity of epilepsy and associated neuropathology in experimental TSC and FCD. Overall, these findings highlight the importance of evaluating the outcome of individual variants on mTOR activity levels and support personalized medicine strategies based on patient variants and mTOR activity level for TSC, FCD, and potentially other mTORopathies.SIGNIFICANCE STATEMENT Tuberous sclerosis complex (TSC) and focal cortical dysplasia (FCD) are epileptogenic cortical malformations caused by pathogenic variants in mechanistic target of rapamycin (mTOR) pathway genes leading to differential mTOR hyperactivation. Here, we present novel findings that neuronal mTOR hyperactivity levels correlate with the severity of epilepsy and associated neuropathology in a mouse model of TSC and FCD. Our findings suggest the need to evaluate the outcome of individual variants on mTOR activity levels in clinical assessments and support personalized medicine strategies based on patient variants and mTOR activity level. Additionally, we present useful modifications to a previously described mouse model of TSC and FCD that allows for titration of seizure frequency and generation of a mild to severe epilepsy phenotype as applicable for preclinical drug testing and mechanistic studies.
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Affiliation(s)
| | | | - Angélique Bordey
- Department of Neurosurgery, and
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut 06520
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43
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Marsan E, Baulac S. Review: Mechanistic target of rapamycin (mTOR) pathway, focal cortical dysplasia and epilepsy. Neuropathol Appl Neurobiol 2019; 44:6-17. [PMID: 29359340 DOI: 10.1111/nan.12463] [Citation(s) in RCA: 124] [Impact Index Per Article: 24.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Accepted: 01/17/2018] [Indexed: 12/19/2022]
Abstract
Over the last decade, there has been increasing evidence that hyperactivation of the mechanistic target of rapamycin (mTOR) pathway is a hallmark of malformations of cortical development such as focal cortical dysplasia (FCD) or hemimegalencephaly. The mTOR pathway governs protein and lipid synthesis, cell growth and proliferation as well as metabolism and autophagy. The molecular genetic aetiology of mTOR hyperactivation has only been recently clarified. This article will review the current and still evolving genetic advances in the elucidation of the molecular basis of FCD. Activating somatic mutations in the MTOR gene are to date the most frequent mutations found in FCD brain specimens.
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Affiliation(s)
- E Marsan
- Department of Genetics and Cytogenetics, AP-HP, Institut du Cerveau et de la Moelle Epinière (ICM) - Hôpital Pitié-Salpêtrière, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, Inserm U1127, CNRS UMR 7225, Paris, France
| | - S Baulac
- Department of Genetics and Cytogenetics, AP-HP, Institut du Cerveau et de la Moelle Epinière (ICM) - Hôpital Pitié-Salpêtrière, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, Inserm U1127, CNRS UMR 7225, Paris, France
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44
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Serra I, Scheldeman C, Bazelot M, Whalley BJ, Dallas ML, de Witte PAM, Williams CM. Cannabidiol modulates phosphorylated rpS6 signalling in a zebrafish model of Tuberous Sclerosis Complex. Behav Brain Res 2019; 363:135-144. [PMID: 30684511 DOI: 10.1016/j.bbr.2019.01.040] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Revised: 01/09/2019] [Accepted: 01/22/2019] [Indexed: 11/30/2022]
Abstract
Tuberous sclerosis complex (TSC) is a rare disease caused by mutations in the TSC1 or TSC2 genes and is characterized by widespread tumour growth, intractable epilepsy, cognitive deficits and autistic behaviour. CBD has been reported to decrease seizures and inhibit tumour cell progression, therefore we sought to determine the influence of CBD on TSC pathology in zebrafish carrying a nonsense mutation in the tsc2 gene. CBD treatment from 6 to 7 days post-fertilization (dpf) induced significant anxiolytic actions without causing sedation. Furthermore, CBD treatment from 3 dpf had no impact on tsc2-/- larvae motility nor their survival. CBD treatment did, however, reduce the number of phosphorylated rpS6 positive cells, and their cross-sectional cell size. This suggests a CBD mediated suppression of mechanistic target of rapamycin (mTOR) activity in the tsc2-/- larval brain. Taken together, these data suggest that CBD selectively modulates levels of phosphorylated rpS6 in the brain and additionally provides an anxiolytic effect. This is pertinent given the alterations in mTOR signalling in experimental models of TSC. Additional work is necessary to identify upstream signal modulation and to further justify the use of CBD as a possible therapeutic strategy to manage TSC.
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Affiliation(s)
- Ines Serra
- School of Psychology and Clinical Language Sciences, University of Reading, Reading, UK; School of Pharmacy, University of Reading, Reading, UK.
| | - Chloë Scheldeman
- Laboratory for Molecular Biodiscovery, Department of Pharmaceutical and Pharmacological Sciences, University of Leuven, Leuven, Belgium.
| | - Michael Bazelot
- GW Research Ltd. Sovereign House, Vision Park, Histon, Cambridge, UK.
| | | | - Mark L Dallas
- School of Pharmacy, University of Reading, Reading, UK.
| | - Peter A M de Witte
- Laboratory for Molecular Biodiscovery, Department of Pharmaceutical and Pharmacological Sciences, University of Leuven, Leuven, Belgium.
| | - Claire M Williams
- School of Psychology and Clinical Language Sciences, University of Reading, Reading, UK.
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45
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Cox RL, Calderon de Anda F, Mangoubi T, Yoshii A. Multiple Critical Periods for Rapamycin Treatment to Correct Structural Defects in Tsc-1-Suppressed Brain. Front Mol Neurosci 2018; 11:409. [PMID: 30467464 PMCID: PMC6237075 DOI: 10.3389/fnmol.2018.00409] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2018] [Accepted: 10/18/2018] [Indexed: 11/18/2022] Open
Abstract
Tuberous sclerosis complex (TSC) is an autosomal dominant neurogenetic disorder affecting the brain and other vital organs. Neurological symptoms include epilepsy, intellectual disability, and autism. TSC is caused by a loss-of-function mutation in the TSC1 or TSC2 gene. These gene products form a protein complex and normally suppress mammalian target of rapamycin (mTOR) activity. mTOR inhibitors have been used to treat subependymal glioma (SEGA) that is a brain tumor characteristic of TSC. However, neuropathology of TSC also involves dysregulated cortical circuit formation including neuronal migration, axodendritic differentiation, and synapse formation. It is currently unknown to what extent mTOR signaling inhibitors correct an alteration in neuronal morphology that have already formed prior to the treatment. Here, we address the efficacy of rapamycin treatment on neuronal migration and dendrite formation. Using in utero electroporation, we suppressed Tsc1 expression in a fraction of neuronal progenitor cells during the fetal period. In embryonic brain slices, we found that more Tsc1-suppressed cells remained within the periventricular zone, and rapamycin treatment facilitated neuronal migration. Postnatally, Tsc1-suppressed pyramidal neurons showed more complex branching of basal dendrites and a higher spine density at postnatal day (P) 28. Aberrant arborization was normalized by rapamycin administration every other day between P1 and P13 but not P15 and P27. In contrast, abnormal spine maturation improved by rapamycin treatment between P15 and P27 but not P1 and P13. Our results indicate that there are multiple critical windows for correcting different aspects of structural abnormalities in TSC, and the responses depend on the stage of neuronal circuit formation. These data warrant a search for an additional therapeutic target to treat neurological symptoms of TSC.
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Affiliation(s)
- Rebecca L Cox
- Department of Brain and Cognitive Science, Massachusetts Institute of Technology, Cambridge, MA, United States.,Feil Family Brain and Mind Research Institute, Weill Cornell Medical College, New York, NY, United States
| | - Froylan Calderon de Anda
- Department of Brain and Cognitive Science, Massachusetts Institute of Technology, Cambridge, MA, United States.,Center for Molecular Neurobiology Hamburg, Research Group Neuronal Development, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Tomer Mangoubi
- Department of Brain and Cognitive Science, Massachusetts Institute of Technology, Cambridge, MA, United States
| | - Akira Yoshii
- Department of Brain and Cognitive Science, Massachusetts Institute of Technology, Cambridge, MA, United States.,Department of Anatomy & Cell Biology, University of Illinois at Chicago, Chicago, IL, United States
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46
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Blair JD, Hockemeyer D, Bateup HS. Genetically engineered human cortical spheroid models of tuberous sclerosis. Nat Med 2018; 24:1568-1578. [PMID: 30127391 PMCID: PMC6261470 DOI: 10.1038/s41591-018-0139-y] [Citation(s) in RCA: 126] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Accepted: 07/06/2018] [Indexed: 01/01/2023]
Abstract
Tuberous sclerosis complex (TSC) is a multisystem developmental disorder caused by mutations in the TSC1 or TSC2 genes, whose protein products are negative regulators of mechanistic target of rapamycin complex 1 signaling. Hallmark pathologies of TSC are cortical tubers-regions of dysmorphic, disorganized neurons and glia in the cortex that are linked to epileptogenesis. To determine the developmental origin of tuber cells, we established human cellular models of TSC by CRISPR-Cas9-mediated gene editing of TSC1 or TSC2 in human pluripotent stem cells (hPSCs). Using heterozygous TSC2 hPSCs with a conditional mutation in the functional allele, we show that mosaic biallelic inactivation during neural progenitor expansion is necessary for the formation of dysplastic cells and increased glia production in three-dimensional cortical spheroids. Our findings provide support for the second-hit model of cortical tuber formation and suggest that variable developmental timing of somatic mutations could contribute to the heterogeneity in the neurological presentation of TSC.
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Affiliation(s)
- John D Blair
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA
| | - Dirk Hockemeyer
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA
| | - Helen S Bateup
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA. .,Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA, USA.
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47
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Díaz-Alonso J, de Salas-Quiroga A, Paraíso-Luna J, García-Rincón D, Garcez PP, Parsons M, Andradas C, Sánchez C, Guillemot F, Guzmán M, Galve-Roperh I. Loss of Cannabinoid CB1 Receptors Induces Cortical Migration Malformations and Increases Seizure Susceptibility. Cereb Cortex 2018; 27:5303-5317. [PMID: 28334226 DOI: 10.1093/cercor/bhw309] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Accepted: 09/12/2016] [Indexed: 12/18/2022] Open
Abstract
Neuronal migration is a fundamental process of brain development, and its disruption underlies devastating neurodevelopmental disorders. The transcriptional programs governing this process are relatively well characterized. However, how environmental cues instruct neuronal migration remains poorly understood. Here, we demonstrate that the cannabinoid CB1 receptor is strictly required for appropriate pyramidal neuron migration in the developing cortex. Acute silencing of the CB1 receptor alters neuronal morphology and impairs radial migration. Consequently, CB1 siRNA-electroporated mice display cortical malformations mimicking subcortical band heterotopias and increased seizure susceptibility in adulthood. Importantly, rescuing the CB1 deficiency-induced radial migration arrest by knockdown of the GTPase protein RhoA restored the hyperexcitable neuronal network and seizure susceptibility. Our findings show that CB1 receptor/RhoA signaling regulates pyramidal neuron migration, and that deficient CB1 receptor signaling may contribute to cortical development malformations leading to refractory epilepsy independently of its canonical neuromodulatory role in the adult brain.
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Affiliation(s)
- Javier Díaz-Alonso
- Department of Biochemistry and Molecular Biology I, Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), and Instituto Universitario de Investigación Neuroquímica (IUIN), Complutense University, 28040 Madrid, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), 28049 Madrid, Spain.,Department of Cellular and Molecular Pharmacology, University of California, San Francisco, CA 94158, USA
| | - Adán de Salas-Quiroga
- Department of Biochemistry and Molecular Biology I, Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), and Instituto Universitario de Investigación Neuroquímica (IUIN), Complutense University, 28040 Madrid, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), 28049 Madrid, Spain
| | - Juan Paraíso-Luna
- Department of Biochemistry and Molecular Biology I, Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), and Instituto Universitario de Investigación Neuroquímica (IUIN), Complutense University, 28040 Madrid, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), 28049 Madrid, Spain
| | - Daniel García-Rincón
- Department of Biochemistry and Molecular Biology I, Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), and Instituto Universitario de Investigación Neuroquímica (IUIN), Complutense University, 28040 Madrid, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), 28049 Madrid, Spain
| | - Patricia P Garcez
- The Francis Crick Institute, Mill Hill Laboratory, The Ridgeway, London NW7 1AA, UK.,Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, 21941-902 Rio de Janeiro, RJ, Brazil
| | - Maddy Parsons
- Randall Division of Cell and Molecular Biophysics, King's College London, London SE1 1UL, UK
| | - Clara Andradas
- Department of Biochemistry and Molecular Biology I, Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), and Instituto Universitario de Investigación Neuroquímica (IUIN), Complutense University, 28040 Madrid, Spain.,Instituto de Investigación Sanitaria Hospital 12 de Octubre, 28041 Madrid, Spain
| | - Cristina Sánchez
- Department of Biochemistry and Molecular Biology I, Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), and Instituto Universitario de Investigación Neuroquímica (IUIN), Complutense University, 28040 Madrid, Spain.,Instituto de Investigación Sanitaria Hospital 12 de Octubre, 28041 Madrid, Spain
| | - François Guillemot
- The Francis Crick Institute, Mill Hill Laboratory, The Ridgeway, London NW7 1AA, UK
| | - Manuel Guzmán
- Department of Biochemistry and Molecular Biology I, Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), and Instituto Universitario de Investigación Neuroquímica (IUIN), Complutense University, 28040 Madrid, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), 28049 Madrid, Spain
| | - Ismael Galve-Roperh
- Department of Biochemistry and Molecular Biology I, Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), and Instituto Universitario de Investigación Neuroquímica (IUIN), Complutense University, 28040 Madrid, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), 28049 Madrid, Spain
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48
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Role of mTOR Complexes in Neurogenesis. Int J Mol Sci 2018; 19:ijms19051544. [PMID: 29789464 PMCID: PMC5983636 DOI: 10.3390/ijms19051544] [Citation(s) in RCA: 94] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Revised: 05/13/2018] [Accepted: 05/16/2018] [Indexed: 12/22/2022] Open
Abstract
Dysregulation of neural stem cells (NSCs) is associated with several neurodevelopmental disorders, including epilepsy and autism spectrum disorder. The mammalian target of rapamycin (mTOR) integrates the intracellular signals to control cell growth, nutrient metabolism, and protein translation. mTOR regulates many functions in the development of the brain, such as proliferation, differentiation, migration, and dendrite formation. In addition, mTOR is important in synaptic formation and plasticity. Abnormalities in mTOR activity is linked with severe deficits in nervous system development, including tumors, autism, and seizures. Dissecting the wide-ranging roles of mTOR activity during critical periods in development will greatly expand our understanding of neurogenesis.
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49
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Abstract
Lysosomes support diverse cellular functions by acting as sites of macromolecule degradation and nutrient recycling. The degradative abilities of lysosomes are conferred by a lumen that is characterized by an acidic pH and which contains numerous hydrolases that support the breakdown of major cellular macromolecules to yield cellular building blocks (amino acids, nucleic acids, sugars, lipids and metals) that are transported into the cytoplasm for their re-use. In addition to these important hydrolytic and recycling functions, lysosomes also serve as a signaling platform that integrates nutrient and metabolic cues to control signaling via the mTORC1 pathway. Due to their extreme longevity, polarity, demands of neurotransmission and metabolic activity, neurons are particularly sensitive to perturbations in lysosome function. The dependence of neurons on optimal lysosome function is highlighted by insights from human genetics that link lysosome dysfunction to a wide range of both rare and common neurological diseases. How then is lysosome function adapted to the unique demands of neurons? This review will focus on the roles played by lysosomes in distinct neuronal sub-compartments, the regulation of neuronal lysosome sub-cellular localization and the implications of such neuronal lysosome regulation for both physiology and disease.
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Affiliation(s)
- Shawn M Ferguson
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT, 06510, United States; Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, CT, 06510, United States.
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50
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Becker AJ. Review: Animal models of acquired epilepsy: insights into mechanisms of human epileptogenesis. Neuropathol Appl Neurobiol 2018; 44:112-129. [DOI: 10.1111/nan.12451] [Citation(s) in RCA: 82] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Accepted: 10/27/2017] [Indexed: 02/06/2023]
Affiliation(s)
- A. J. Becker
- Section for Translational Epilepsy Research; Department of Neuropathology; University of Bonn Medical Center; Bonn Germany
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