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Brown JA, Faley SL, Judge M, Ward P, Ihrie RA, Carson R, Armstrong L, Sahin M, Wikswo JP, Ess KC, Neely MD. Rescue of impaired blood-brain barrier in tuberous sclerosis complex patient derived neurovascular unit. J Neurodev Disord 2024; 16:27. [PMID: 38783199 PMCID: PMC11112784 DOI: 10.1186/s11689-024-09543-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Accepted: 05/03/2024] [Indexed: 05/25/2024] Open
Abstract
BACKGROUND Tuberous sclerosis complex (TSC) is a multi-system genetic disease that causes benign tumors in the brain and other vital organs. The most debilitating symptoms result from involvement of the central nervous system and lead to a multitude of severe symptoms including seizures, intellectual disability, autism, and behavioral problems. TSC is caused by heterozygous mutations of either the TSC1 or TSC2 gene and dysregulation of mTOR kinase with its multifaceted downstream signaling alterations is central to disease pathogenesis. Although the neurological sequelae of the disease are well established, little is known about how these mutations might affect cellular components and the function of the blood-brain barrier (BBB). METHODS We generated TSC disease-specific cell models of the BBB by leveraging human induced pluripotent stem cell and microfluidic cell culture technologies. RESULTS Using microphysiological systems, we demonstrate that a BBB generated from TSC2 heterozygous mutant cells shows increased permeability. This can be rescued by wild type astrocytes or by treatment with rapamycin, an mTOR kinase inhibitor. CONCLUSION Our results demonstrate the utility of microphysiological systems to study human neurological disorders and advance our knowledge of cell lineages contributing to TSC pathogenesis and informs future therapeutics.
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Affiliation(s)
- Jacquelyn A Brown
- Department of Physics and Astronomy, Vanderbilt University, Nashville, USA
- Vanderbilt Institute for Integrative Biosystems Research and Education, Vanderbilt University, Nashville, USA
| | - Shannon L Faley
- Department of Physics and Astronomy, Vanderbilt University, Nashville, USA
- Vanderbilt Institute for Integrative Biosystems Research and Education, Vanderbilt University, Nashville, USA
| | - Monika Judge
- Department of Physics and Astronomy, Vanderbilt University, Nashville, USA
- Vanderbilt Institute for Integrative Biosystems Research and Education, Vanderbilt University, Nashville, USA
| | - Patricia Ward
- Department of Physics and Astronomy, Vanderbilt University, Nashville, USA
- Vanderbilt Institute for Integrative Biosystems Research and Education, Vanderbilt University, Nashville, USA
| | - Rebecca A Ihrie
- Department of Cell & Developmental Biology, Vanderbilt University, Nashville, USA
- Neurological Surgery, Vanderbilt University Medical Center, Nashville, USA
| | - Robert Carson
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, USA
| | - Laura Armstrong
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, USA
| | - Mustafa Sahin
- Rosamund Stone Translational Neuroscience Center, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, USA
| | - John P Wikswo
- Department of Physics and Astronomy, Vanderbilt University, Nashville, USA
- Vanderbilt Institute for Integrative Biosystems Research and Education, Vanderbilt University, Nashville, USA
- Department of Biomedical Engineering, Vanderbilt University, Nashville, USA
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, USA
| | - Kevin C Ess
- Neurological Surgery, Vanderbilt University Medical Center, Nashville, USA.
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, USA.
- Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, USA.
| | - M Diana Neely
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, USA.
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Man A, Di Scipio M, Grewal S, Suk Y, Trinari E, Ejaz R, Whitney R. The Genetics of Tuberous Sclerosis Complex and Related mTORopathies: Current Understanding and Future Directions. Genes (Basel) 2024; 15:332. [PMID: 38540392 PMCID: PMC10970281 DOI: 10.3390/genes15030332] [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: 02/12/2024] [Revised: 03/02/2024] [Accepted: 03/02/2024] [Indexed: 06/14/2024] Open
Abstract
The mechanistic target of rapamycin (mTOR) pathway serves as a master regulator of cell growth, proliferation, and survival. Upregulation of the mTOR pathway has been shown to cause malformations of cortical development, medically refractory epilepsies, and neurodevelopmental disorders, collectively described as mTORopathies. Tuberous sclerosis complex (TSC) serves as the prototypical mTORopathy. Characterized by the development of benign tumors in multiple organs, pathogenic variants in TSC1 or TSC2 disrupt the TSC protein complex, a negative regulator of the mTOR pathway. Variants in critical domains of the TSC complex, especially in the catalytic TSC2 subunit, correlate with increased disease severity. Variants in less crucial exons and non-coding regions, as well as those undetectable with conventional testing, may lead to milder phenotypes. Despite the assumption of complete penetrance, expressivity varies within families, and certain variants delay disease onset with milder neurological effects. Understanding these genotype-phenotype correlations is crucial for effective clinical management. Notably, 15% of patients have no mutation identified by conventional genetic testing, with the majority of cases postulated to be caused by somatic TSC1/TSC2 variants which present complex diagnostic challenges. Advancements in genetic testing, prenatal screening, and precision medicine hold promise for changing the diagnostic and treatment paradigm for TSC and related mTORopathies. Herein, we explore the genetic and molecular mechanisms of TSC and other mTORopathies, emphasizing contemporary genetic methods in understanding and diagnosing the condition.
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Affiliation(s)
- Alice Man
- Michael G. DeGroote School of Medicine, McMaster University, Hamilton, ON L8S 4L8, Canada
| | - Matteo Di Scipio
- Michael G. DeGroote School of Medicine, McMaster University, Hamilton, ON L8S 4L8, Canada
| | - Shan Grewal
- Michael G. DeGroote School of Medicine, McMaster University, Hamilton, ON L8S 4L8, Canada
| | - Yujin Suk
- Michael G. DeGroote School of Medicine, McMaster University, Hamilton, ON L8S 4L8, Canada
| | - Elisabetta Trinari
- Division of Developmental Pediatrics, Department of Pediatrics, McMaster Children’s Hospital, Hamilton, ON L8N 3Z5, Canada
| | - Resham Ejaz
- Division of Genetics, Department of Pediatrics, McMaster University, Hamilton, ON L8S 4L8, Canada
| | - Robyn Whitney
- Division of Neurology, Department of Pediatrics, McMaster University, Hamilton, ON L8S 4L8, Canada
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Guo D, Zhang B, Han L, Rensing NR, Wong M. Cerebral vascular and blood brain-barrier abnormalities in a mouse model of epilepsy and tuberous sclerosis complex. Epilepsia 2024; 65:483-496. [PMID: 38049961 PMCID: PMC10922951 DOI: 10.1111/epi.17848] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2023] [Revised: 11/29/2023] [Accepted: 11/30/2023] [Indexed: 12/06/2023]
Abstract
OBJECTIVE Tuberous sclerosis complex (TSC) is a genetic disorder, characterized by tumor formation in the brain and other organs, and severe neurological symptoms, such as epilepsy. Abnormal vascular endothelial growth factor (VEGF) expression may promote angiogenesis in kidney and lung tumors in TSC and has been identified in brain specimens from TSC patients, but the role of VEGF and vascular abnormalities in neurological manifestations of TSC is poorly defined. In this study, we investigated abnormalities in brain VEGF expression, cerebral blood vessel anatomy, and blood-brain barrier (BBB) structure and function in a mouse model of TSC. METHODS Tsc1GFAP CKO mice were used to investigate VEGF expression and vascular abnormalities in the brain by Western blotting and immunohistochemical analysis of vascular and BBB markers. In vivo two-photon imaging was used to assess BBB permeability to normally impenetrable fluorescently labeled compounds. The effect of mechanistic target of rapamycin (mTOR) pathway inhibitors, VEGF receptor antagonists (apatinib), or BBB stabilizers (RepSox) was assessed in some of these assays, as well as on seizures by video-electroencephalography. RESULTS VEGF expression was elevated in cortex of Tsc1GFAP CKO mice, which was reversed by the mTOR inhibitor rapamycin. Tsc1GFAP CKO mice exhibited increased cerebral angiogenesis and vascular complexity in cortex and hippocampus, which were reversed by the VEGF receptor antagonist apatinib. BBB permeability was abnormally increased and BBB-related tight junction proteins occludin and claudin-5 were decreased in Tsc1GFAP CKO mice, also in an apatinib- and RepSox-dependent manner. The BBB stabilizer (RepSox), but not the VEGF receptor antagonist (apatinib), decreased seizures and improved survival in Tsc1GFAP CKO mice. SIGNIFICANCE Increased brain VEGF expression is dependent on mTOR pathway activation and promotes cerebral vascular abnormalities and increased BBB permeability in a mouse model of TSC. BBB modulation may affect epileptogenesis and represent a rational treatment for epilepsy in TSC.
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Affiliation(s)
- Dongjun Guo
- Department of Neurology and Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Bo Zhang
- Department of Neurology and Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Lirong Han
- Department of Neurology and Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Nicholas R Rensing
- Department of Neurology and Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Michael Wong
- Department of Neurology and Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, Missouri, USA
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4
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Brown JA, Faley SL, Judge M, Ward P, Ihrie RA, Carson R, Armstrong L, Sahin M, Wikswo JP, Ess KC, Neely MD. Rescue of Impaired Blood-Brain Barrier in Tuberous Sclerosis Complex Patient Derived Neurovascular Unit. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.15.571738. [PMID: 38168450 PMCID: PMC10760190 DOI: 10.1101/2023.12.15.571738] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
Tuberous sclerosis complex (TSC) is a multi-system genetic disease that causes benign tumors in the brain and other vital organs. The most debilitating symptoms result from involvement of the central nervous system and lead to a multitude of severe symptoms including seizures, intellectual disability, autism, and behavioral problems. TSC is caused by heterozygous mutations of either the TSC1 or TSC2 gene. Dysregulation of mTOR kinase with its multifaceted downstream signaling alterations is central to disease pathogenesis. Although the neurological sequelae of the disease are well established, little is known about how these mutations might affect cellular components and the function of the blood-brain barrier (BBB). We generated disease-specific cell models of the BBB by leveraging human induced pluripotent stem cell and microfluidic cell culture technologies. Using these microphysiological systems, we demonstrate that the BBB generated from TSC2 heterozygous mutant cells shows increased permeability which can be rescued by wild type astrocytes and with treatment with rapamycin, an mTOR kinase inhibitor. Our results further demonstrate the utility of microphysiological systems to study human neurological disorders and advance our knowledge of the cell lineages contributing to TSC pathogenesis.
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Affiliation(s)
- Jacquelyn A Brown
- Dept. of Physics and Astronomy, Vanderbilt University
- Vanderbilt Institute for Integrative Biosystems Research and Education, Vanderbilt University
| | - Shannon L Faley
- Dept. of Physics and Astronomy, Vanderbilt University
- Vanderbilt Institute for Integrative Biosystems Research and Education, Vanderbilt University
| | - Monika Judge
- Dept. of Physics and Astronomy, Vanderbilt University
- Vanderbilt Institute for Integrative Biosystems Research and Education, Vanderbilt University
| | - Patricia Ward
- Dept. of Physics and Astronomy, Vanderbilt University
- Vanderbilt Institute for Integrative Biosystems Research and Education, Vanderbilt University
| | - Rebecca A Ihrie
- Dept. of Cell & Developmental Biology, Vanderbilt University
- Neurological Surgery, Vanderbilt University Medical Center
| | - Robert Carson
- Dept. of Pediatrics, Vanderbilt University Medical Center
| | | | - Mustafa Sahin
- Rosamund Stone Translational Neuroscience Center, Dept. of Neurology, Boston Children's Hospital, Harvard Medical School
| | - John P Wikswo
- Dept. of Physics and Astronomy, Vanderbilt University
- Vanderbilt Institute for Integrative Biosystems Research and Education, Vanderbilt University
- Dept. of Biomedical Engineering, Vanderbilt University
- Dept. of Molecular Physiology and Biophysics, Vanderbilt University
| | - Kevin C Ess
- Neurological Surgery, Vanderbilt University Medical Center
- Dept. of Pediatrics, Vanderbilt University Medical Center
| | - M Diana Neely
- Dept. of Pediatrics, Vanderbilt University Medical Center
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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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Davletshin AI, Matveeva AA, Poletaeva II, Evgen'ev MB, Garbuz DG. The role of molecular chaperones in the mechanisms of epileptogenesis. Cell Stress Chaperones 2023; 28:599-619. [PMID: 37755620 PMCID: PMC10746656 DOI: 10.1007/s12192-023-01378-1] [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: 07/17/2023] [Revised: 08/30/2023] [Accepted: 09/08/2023] [Indexed: 09/28/2023] Open
Abstract
Epilepsy is a group of neurological diseases which requires significant economic costs for the treatment and care of patients. The central point of epileptogenesis stems from the failure of synaptic signal transmission mechanisms, leading to excessive synchronous excitation of neurons and characteristic epileptic electroencephalogram activity, in typical cases being manifested as seizures and loss of consciousness. The causes of epilepsy are extremely diverse, which is one of the reasons for the complexity of selecting a treatment regimen for each individual case and the high frequency of pharmacoresistant cases. Therefore, the search for new drugs and methods of epilepsy treatment requires an advanced study of the molecular mechanisms of epileptogenesis. In this regard, the investigation of molecular chaperones as potential mediators of epileptogenesis seems promising because the chaperones are involved in the processing and regulation of the activity of many key proteins directly responsible for the generation of abnormal neuronal excitation in epilepsy. In this review, we try to systematize current data on the role of molecular chaperones in epileptogenesis and discuss the prospects for the use of chemical modulators of various chaperone groups' activity as promising antiepileptic drugs.
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Affiliation(s)
| | - Anna A Matveeva
- Engelhardt Institute of Molecular Biology RAS, 119991, Moscow, Russia
- Moscow Institute of Physics and Technology, 141700, Dolgoprudny, Moscow Region, Russia
| | - Inga I Poletaeva
- Biology Department, Lomonosov Moscow State University, 119991, Moscow, Russia
| | | | - David G Garbuz
- Engelhardt Institute of Molecular Biology RAS, 119991, Moscow, Russia
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Kotchetkov P, Blakeley N, Lacoste B. Involvement of brain metabolism in neurodevelopmental disorders. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2023; 173:67-113. [PMID: 37993180 DOI: 10.1016/bs.irn.2023.08.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2023]
Abstract
Neurodevelopmental disorders (NDDs) affect a significant portion of the global population and have a substantial social and economic impact worldwide. Most NDDs manifest in early childhood and are characterized by deficits in cognition, communication, social interaction and motor control. Due to a limited understanding of the etiology of NDDs, current treatment options primarily focus on symptom management rather than on curative solutions. Moreover, research on NDDs is problematic due to its reliance on a neurocentric approach. However, recent studies are broadening the scope of research on NDDs, to include dysregulations within a diverse network of brain cell types, including vascular and glial cells. This review aims to summarize studies from the past few decades on potential new contributions to the etiology of NDDs, with a special focus on metabolic signatures of various brain cells. In particular, we aim to convey how the metabolic functions are intimately linked to the onset and/or progression of common NDDs such as autism spectrum disorders, fragile X syndrome, Rett syndrome and Down syndrome.
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Affiliation(s)
- Pavel Kotchetkov
- Neuroscience Program, The Ottawa Hospital Research Institute, Ottawa, ON, Canada; Department of Cellular & Molecular Medicine, University of Ottawa, Ottawa, ON, Canada
| | - Nicole Blakeley
- Neuroscience Program, The Ottawa Hospital Research Institute, Ottawa, ON, Canada; Department of Cellular & Molecular Medicine, University of Ottawa, Ottawa, ON, Canada
| | - Baptiste Lacoste
- Neuroscience Program, The Ottawa Hospital Research Institute, Ottawa, ON, Canada; Department of Cellular & Molecular Medicine, University of Ottawa, Ottawa, ON, Canada; University of Ottawa Brain and Mind Research Institute, Ottawa, ON, Canada.
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Bychkova E, Dorofeeva M, Levov A, Kislyakov A, Karandasheva K, Strelnikov V, Anoshkin K. Specific Features of Focal Cortical Dysplasia in Tuberous Sclerosis Complex. Curr Issues Mol Biol 2023; 45:3977-3996. [PMID: 37232723 DOI: 10.3390/cimb45050254] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Revised: 04/23/2023] [Accepted: 04/26/2023] [Indexed: 05/27/2023] Open
Abstract
Patients with tuberous sclerosis complex present with cognitive, behavioral, and psychiatric impairments, such as intellectual disabilities, autism spectrum disorders, and drug-resistant epilepsy. It has been shown that these disorders are associated with the presence of cortical tubers. Tuberous sclerosis complex results from inactivating mutations in the TSC1 or TSC2 genes, resulting in hyperactivation of the mTOR signaling pathway, which regulates cell growth, proliferation, survival, and autophagy. TSC1 and TSC2 are classified as tumor suppressor genes and function according to Knudson's two-hit hypothesis, which requires both alleles to be damaged for tumor formation. However, a second-hit mutation is a rare event in cortical tubers. This suggests that the molecular mechanism of cortical tuber formation may be more complicated and requires further research. This review highlights the issues of molecular genetics and genotype-phenotype correlations, considers histopathological characteristics and the mechanism of morphogenesis of cortical tubers, and also presents data on the relationship between these formations and the development of neurological manifestations, as well as treatment options.
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Affiliation(s)
- Ekaterina Bychkova
- Research Centre for Medical Genetics, Moskvorechye Street 1, 115522 Moscow, Russia
- Faculty of Biomedicine, Pirogov Russian National Research Medical University, Ostrovityanova Street 1, 117997 Moscow, Russia
| | - Marina Dorofeeva
- Veltischev Research and Clinical Institute for Pediatrics and Pediatric Surgery, Pirogov Russian National Research Medical University, Taldomskaya 2, 125412 Moscow, Russia
| | - Aleksandr Levov
- Morozov Children's City Clinical Hospital, 4th Dobryninsky Lane, 1/9, 119049 Moscow, Russia
| | - Alexey Kislyakov
- Morozov Children's City Clinical Hospital, 4th Dobryninsky Lane, 1/9, 119049 Moscow, Russia
| | | | - Vladimir Strelnikov
- Research Centre for Medical Genetics, Moskvorechye Street 1, 115522 Moscow, Russia
| | - Kirill Anoshkin
- Research Centre for Medical Genetics, Moskvorechye Street 1, 115522 Moscow, Russia
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Śmiałek D, Kotulska K, Duda A, Jóźwiak S. Effect of mTOR Inhibitors in Epilepsy Treatment in Children with Tuberous Sclerosis Complex Under 2 Years of Age. Neurol Ther 2023; 12:931-946. [PMID: 37085686 DOI: 10.1007/s40120-023-00476-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Accepted: 03/28/2023] [Indexed: 04/23/2023] Open
Abstract
INTRODUCTION Mechanistic target of rapamycin (mTOR) inhibitors sirolimus and everolimus are an effective therapy for subependymal giant cell astrocytomas, cardiac rhabdomyomas, renal angiomyolipomas, and lymphangioleiomyomatosis associated with tuberous sclerosis complex (TSC). Everolimus was recently approved in the EU and the USA for the treatment of refractory focal-onset seizures. Despite frequent use of mTOR inhibitors, there are only a few studies on their effect on epilepsy control in children under 2 years of age. This study aims to assess the effect of adjunctive mTOR inhibitor treatment on seizure frequency in this age group. METHODS We performed retrospective data analysis of medical records of patients with TSC who initiated sirolimus or everolimus under the age of 2 years. Participants' antiseizure medication was adjusted according to their epilepsy control independently from mTOR inhibitor administration. The data was assessed separately for patients treated with mTOR inhibitors before and after the onset of seizures. We also compared the treatment group with a matched control group. The follow-up duration was up to 24 months. RESULTS Twenty-one patients with TSC from two clinical centers were included in the study. Nine participants had no history of seizures before mTOR inhibitor initiation. Twelve reported active epilepsy in the month prior to treatment initiation. Most patients treated preventively with mTOR inhibitors did not report active epilepsy at the end of their follow-up. In the second group, the mean frequency of seizures decreased with time. According to the comparative analysis, seizure control was better in the groups treated with mTOR inhibitors. CONCLUSION Patients with TSC treated with mTOR inhibitors demonstrated better seizure control than individuals without this treatment. Adjunctive pharmacotherapy with mTOR inhibitors appears to have a beneficial effect on epilepsy outcome in young children. Further prospective clinical trials should be conducted to determine the efficacy of mTOR inhibitors on epilepsy in patients with TSC under the age of 2 years.
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Affiliation(s)
- Dominika Śmiałek
- Department of Pediatric Neurology, Medical University of Warsaw, Warsaw, Poland.
| | - Katarzyna Kotulska
- Department of Neurology and Epileptology, The Children's Memorial Health Institute, Warsaw, Poland
| | | | - Sergiusz Jóźwiak
- Department of Pediatric Neurology, Medical University of Warsaw, Warsaw, Poland
- Research Department, The Children's Memorial Health Institute, Warsaw, Poland
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Levy RJ, Paşca SP. What Have Organoids and Assembloids Taught Us About the Pathophysiology of Neuropsychiatric Disorders? Biol Psychiatry 2023; 93:632-641. [PMID: 36739210 DOI: 10.1016/j.biopsych.2022.11.017] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Revised: 11/11/2022] [Accepted: 11/28/2022] [Indexed: 12/03/2022]
Abstract
Neuropsychiatric research has been impeded by limited access to human brain tissue, especially from early stages of neurodevelopment when the pathophysiology of many childhood-onset disorders is initiated. Neural organoids are 3-dimensional, self-organizing, multicellular structures generated from pluripotent stem cells that recapitulate some of the cell diversity, cytoarchitecture, and functional features of domains of the developing nervous system. Assembloids are 3-dimensional, self-organizing cultures created by the combination of two or more distinctly patterned organoids or an organoid plus additional cell or tissue type(s) that are used to model cell migration and connectivity. Here we review recent advances in neuropsychiatric disorder research using organoid and assembloid models to study the role of disease-relevant genes and mutations, as well as the impact of environmental risk factors on neural development. We also highlight some of the advantages and limitations of these model systems in bringing insights into the pathophysiology of neuropsychiatric disorders.
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Affiliation(s)
- Rebecca J Levy
- Department of Neurology & Neurological Sciences, Stanford University, Stanford, California; Stanford Brain Organogenesis, Wu Tsai Neurosciences Institute & Bio-X, Stanford University, Stanford, California
| | - Sergiu P Paşca
- Stanford Brain Organogenesis, Wu Tsai Neurosciences Institute & Bio-X, Stanford University, Stanford, California; Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, California.
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11
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Auvin S, Baulac S. mTOR-therapy and targeted treatment opportunities in mTOR-related epilepsies associated with cortical malformations. Rev Neurol (Paris) 2023; 179:337-344. [PMID: 36906459 DOI: 10.1016/j.neurol.2022.12.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Revised: 12/08/2022] [Accepted: 12/13/2022] [Indexed: 03/11/2023]
Abstract
Dysregulation of the mTOR pathway is now well documented in several neurodevelopmental disorders associated with epilepsy. Mutations of mTOR pathway genes are involved in tuberous sclerosis complex (TSC) as well as in a range of cortical malformations from hemimegalencephaly (HME) to type II focal cortical dysplasia (FCD II), leading to the concept of "mTORopathies" (mTOR pathway-related malformations). This suggests that mTOR inhibitors (notably rapamycin (sirolimus), and everolimus) could be used as antiseizure medication. In this review, we provide an overview of pharmacological treatments targeting the mTOR pathway for epilepsy based on lectures from the ILAE French Chapter meeting in October 2022 in Grenoble. There is strong preclinical evidence for the antiseizure effects of mTOR inhibitors in TSC and cortical malformation mouse models. There are also open studies on the antiseizure effects of mTOR inhibitors, as well as one phase III study showing the antiseizure effect of everolimus in TSC patients. Finally, we discuss to which extent mTOR inhibitors might have properties beyond the antiseizure effect on associated neuropsychiatric comorbidities. We also discuss a new way of treatment on the mTOR pathways.
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Affiliation(s)
- S Auvin
- Service de neurologie pédiatrique, EpiCARE ERN membre, Hôpital Robert Debré, AP-HP, Paris, France; Université Paris-Cité, Inserm NeuroDiderot, Paris, France; Institut Universitaire de France (IUF), Paris, France.
| | - S Baulac
- Sorbonne Université, Institut du Cerveau - Paris Brain Institute - ICM, Inserm, CNRS, Hôpital de la Pitié Salpêtrière, 75013 Paris, France
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12
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Fidalgo da Silva E, Abu Khatir B, Drouillard C, Hinch I, Davis GO, Sameem M, Patel R, Fong J, Lubanska D, Porter LA. Tuberin levels during cellular differentiation in brain development. Differentiation 2023; 130:43-50. [PMID: 36608575 DOI: 10.1016/j.diff.2022.12.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Revised: 12/13/2022] [Accepted: 12/21/2022] [Indexed: 12/26/2022]
Abstract
Tuberin is a member of a large protein complex, Tuberous Sclerosis Complex (TSC), and acts as a sensor for nutrient status regulating protein synthesis and cell cycle progression. Mutations in the Tuberin gene, TSC2, permits the formation of tumors that can lead to developmental defects in many organ systems, including the central nervous system. Tuberin is expressed in the brain throughout development and levels of Tuberin have been found to decrease during neuronal differentiation in cell lines in vitro. Our current work investigates the levels of Tuberin at two stages of embryonic development in vivo, and we study the mRNA and protein levels during a time course using immortalized cell lines in vitro. Our results show that total Tuberin levels are tightly regulated through developmental stages in the embryonic brain. At a cell biology level, we show that Tuberin levels are higher when cells are cultured as neurospheres, and knockdown of Tuberin results in a reduction in the number of neurospheres. This functional data supports the hypothesis that Tuberin is an important regulator of stemness and the reduction of Tuberin levels might support functional differentiation in the central nervous system. Understanding how Tuberin expression is regulated throughout neural development is essential to fully comprehend the role of this protein in several developmental and neural pathologies.
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Affiliation(s)
- Elizabeth Fidalgo da Silva
- Department of Biomedical Sciences, University of Windsor, 401 Sunset Ave. Windsor, Ontario, N9B 3P4, Canada
| | - Bashaer Abu Khatir
- Department of Biomedical Sciences, University of Windsor, 401 Sunset Ave. Windsor, Ontario, N9B 3P4, Canada
| | - Christopher Drouillard
- Department of Biomedical Sciences, University of Windsor, 401 Sunset Ave. Windsor, Ontario, N9B 3P4, Canada
| | - Isabelle Hinch
- Department of Biomedical Sciences, University of Windsor, 401 Sunset Ave. Windsor, Ontario, N9B 3P4, Canada
| | - Gordon Omar Davis
- Department of Biomedical Sciences, University of Windsor, 401 Sunset Ave. Windsor, Ontario, N9B 3P4, Canada
| | - Mariam Sameem
- Department of Biomedical Sciences, University of Windsor, 401 Sunset Ave. Windsor, Ontario, N9B 3P4, Canada
| | - Rutu Patel
- Department of Biomedical Sciences, University of Windsor, 401 Sunset Ave. Windsor, Ontario, N9B 3P4, Canada
| | - Jackie Fong
- Department of Biomedical Sciences, University of Windsor, 401 Sunset Ave. Windsor, Ontario, N9B 3P4, Canada
| | - Dorota Lubanska
- Department of Biomedical Sciences, University of Windsor, 401 Sunset Ave. Windsor, Ontario, N9B 3P4, Canada
| | - Lisa A Porter
- Department of Biomedical Sciences, University of Windsor, 401 Sunset Ave. Windsor, Ontario, N9B 3P4, Canada.
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13
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Kashii H, Kasai S, Sato A, Hagino Y, Nishito Y, Kobayashi T, Hino O, Mizuguchi M, Ikeda K. Tsc2 mutation rather than Tsc1 mutation dominantly causes a social deficit in a mouse model of tuberous sclerosis complex. Hum Genomics 2023; 17:4. [PMID: 36732866 PMCID: PMC9893559 DOI: 10.1186/s40246-023-00450-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Accepted: 01/18/2023] [Indexed: 02/04/2023] Open
Abstract
BACKGROUND Tuberous sclerosis complex (TSC) is an autosomal dominant disorder that is associated with neurological symptoms, including autism spectrum disorder. Tuberous sclerosis complex is caused by pathogenic germline mutations of either the TSC1 or TSC2 gene, but somatic mutations were identified in both genes, and the combined effects of TSC1 and TSC2 mutations have been unknown. METHODS The present study investigated social behaviors by the social interaction test and three-chambered sociability tests, effects of rapamycin treatment, and gene expression profiles with a gene expression microarray in Tsc1 and Tsc2 double heterozygous mutant (TscD+/-) mice. RESULTS TscD+/- mice exhibited impairments in social behaviors, and the severity of impairments was similar to Tsc2+/- mice rather than Tsc1+/- mice. Impairments in social behaviors were rescued by rapamycin treatment in all mutant mice. Gene expression profiles in the brain were greatly altered in TscD+/- mice more than in Tsc1+/- and Tsc2+/- mice. The gene expression changes compared with wild type (WT) mice were similar between TscD+/- and Tsc2+/- mice, and the overlapping genes whose expression was altered in mutant mice compared with WT mice were enriched in the neoplasm- and inflammation-related canonical pathways. The "signal transducer and activator of transcription 3, interferon regulatory factor 1, interferon regulatory factor 4, interleukin-2R α chain, and interferon-γ" signaling pathway, which is initiated from signal transducer and activator of transcription 4 and PDZ and LIM domain protein 2, was associated with impairments in social behaviors in all mutant mice. LIMITATIONS It is unclear whether the signaling pathway also plays a critical role in autism spectrum disorders not caused by Tsc1 and Tsc2 mutations. CONCLUSIONS These findings suggest that TSC1 and TSC2 double mutations cause autistic behaviors similarly to TSC2 mutations, although significant changes in gene expression were attributable to the double mutations. These findings contribute to the knowledge of genotype-phenotype correlations in TSC and suggest that mutations in both the TSC1 and TSC2 genes act in concert to cause neurological symptoms, including autism spectrum disorder.
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Affiliation(s)
- Hirofumi Kashii
- grid.272456.00000 0000 9343 3630Addictive Substance Project, Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kamikitazawa, Setagaya-Ku, Tokyo, 156-8506 Japan ,grid.417106.5Department of Neuropediatrics, Tokyo Metropolitan Neurological Hospital, 2-6-1 Musashidai, Fuchu, Tokyo, 183-0042 Japan
| | - Shinya Kasai
- grid.272456.00000 0000 9343 3630Addictive Substance Project, Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kamikitazawa, Setagaya-Ku, Tokyo, 156-8506 Japan
| | - Atsushi Sato
- grid.272456.00000 0000 9343 3630Addictive Substance Project, Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kamikitazawa, Setagaya-Ku, Tokyo, 156-8506 Japan ,grid.412708.80000 0004 1764 7572Department of Pediatrics, The University of Tokyo Hospital, 7-3-1 Hongo, Bunkyo-Ku, Tokyo, 113-8655 Japan
| | - Yoko Hagino
- grid.272456.00000 0000 9343 3630Addictive Substance Project, Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kamikitazawa, Setagaya-Ku, Tokyo, 156-8506 Japan
| | - Yasumasa Nishito
- grid.272456.00000 0000 9343 3630Center for Basic Technology Research, Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kamikitazawa, Setagaya-Ku, Tokyo, 156-8506 Japan
| | - Toshiyuki Kobayashi
- grid.258269.20000 0004 1762 2738Department of Pathology and Oncology, Juntendo University School of Medicine, 2-1-1 Hongo, Bunkyo-Ku, Tokyo, 113-8421 Japan
| | - Okio Hino
- grid.258269.20000 0004 1762 2738Department of Pathology and Oncology, Juntendo University School of Medicine, 2-1-1 Hongo, Bunkyo-Ku, Tokyo, 113-8421 Japan
| | - Masashi Mizuguchi
- Department of Pediatrics, National Rehabilitation Center for Children with Disabilities, 1-1-10 Komone, Itabashi-Ku, Tokyo, 173-0037 Japan
| | - Kazutaka Ikeda
- Addictive Substance Project, Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kamikitazawa, Setagaya-Ku, Tokyo, 156-8506, Japan.
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14
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Dissecting the roles of the Tuberin protein in the subcellular localization of the G2/M Cyclin, Cyclin B1. PLoS One 2022; 17:e0272741. [PMID: 35947627 PMCID: PMC9365131 DOI: 10.1371/journal.pone.0272741] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Accepted: 07/26/2022] [Indexed: 11/20/2022] Open
Abstract
Tuberin is a major component of the protein regulatory complex known as the Tuberous Sclerosis Complex and plays a crucial role in cell cycle progression and protein synthesis. Mutations in the Tuberin gene, TSC2, lead to the formation of benign tumors in many organ systems and causes the Tuberous Sclerosis Complex disorder. Genotypes ranging from point mutations to large deletions in the TSC2 gene have been clinically characterized with a wide range of phenotypes from skin tumors to large brain tumors. Our lab has previously demonstrated that Tuberin can directly bind and regulate the timing of nuclear transport of the G2/M cyclin, Cyclin B1. Herein we study the consequence of one clinically relevant truncation in the Tuberin protein on cell cycle function. We demonstrate that exogenous expression of a fragment of the N-term region of Tuberin alters the subcellular localization of Cyclin B1 and increases cell proliferation. This adds to our body of information about the residues within Tuberin responsible for regulating the cytoplasmic retention of Cyclin B1 and supports the phenotypic data seen in the clinic with Tuberous Sclerosis Complex patients harbouring similar large deletions in Tuberin.
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15
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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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16
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Emerging Link between Tsc1 and FNIP Co-Chaperones of Hsp90 and Cancer. Biomolecules 2022; 12:biom12070928. [PMID: 35883484 PMCID: PMC9312812 DOI: 10.3390/biom12070928] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Revised: 06/27/2022] [Accepted: 06/28/2022] [Indexed: 11/17/2022] Open
Abstract
Heat shock protein-90 (Hsp90) is an ATP-dependent molecular chaperone that is tightly regulated by a group of proteins termed co-chaperones. This chaperone system is essential for the stabilization and activation of many key signaling proteins. Recent identification of the co-chaperones FNIP1, FNIP2, and Tsc1 has broadened the spectrum of Hsp90 regulators. These new co-chaperones mediate the stability of critical tumor suppressors FLCN and Tsc2 as well as the various classes of Hsp90 kinase and non-kinase clients. Many early observations of the roles of FNIP1, FNIP2, and Tsc1 suggested functions independent of FLCN and Tsc2 but have not been fully delineated. Given the broad cellular impact of Hsp90-dependent signaling, it is possible to explain the cellular activities of these new co-chaperones by their influence on Hsp90 function. Here, we review the literature on FNIP1, FNIP2, and Tsc1 as co-chaperones and discuss the potential downstream impact of this regulation on normal cellular function and in human diseases.
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17
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Serra I, Stravs A, Osório C, Oyaga MR, Schonewille M, Tudorache C, Badura A. Tsc1 Haploinsufficiency Leads to Pax2 Dysregulation in the Developing Murine Cerebellum. Front Mol Neurosci 2022; 15:831687. [PMID: 35645731 PMCID: PMC9137405 DOI: 10.3389/fnmol.2022.831687] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Accepted: 04/04/2022] [Indexed: 12/03/2022] Open
Abstract
Tuberous sclerosis complex 1 (TSC1) is a tumor suppressor that promotes the inhibition of mechanistic target of rapamycin (mTOR) pathway, and mutations in TSC1 lead to a rare complex disorder of the same name. Despite phenotype heterogeneity, up to 50% of TSC patients present with autism spectrum disorder (ASD). Consequently, TSC models are often used to probe molecular and behavioral mechanisms of ASD development. Amongst the different brain areas proposed to play a role in the development of ASD, the cerebellum is commonly reported to be altered, and cerebellar-specific deletion of Tsc1 in mice is sufficient to induce ASD-like phenotypes. However, despite these functional changes, whether Tsc1 haploinsufficiency affects cerebellar development is still largely unknown. Given that the mTOR pathway is a master regulator of cell replication and migration, we hypothesized that dysregulation of this pathway would also disrupt the development of cell populations during critical periods of cerebellar development. Here, we used a mouse model of TSC to investigate gene and protein expression during embryonic and early postnatal periods of cerebellar development. We found that, at E18 and P7, mRNA levels of the cerebellar inhibitory interneuron marker paired box gene 2 (Pax2) were dysregulated. This dysregulation was accompanied by changes in the expression of mTOR pathway-related genes and downstream phosphorylation of S6. Differential gene correlation analysis revealed dynamic changes in correlated gene pairs across development, with an overall loss of correlation between mTOR- and cerebellar-related genes in Tsc1 mutants compared to controls. We corroborated the genetic findings by characterizing the mTOR pathway and cerebellar development on protein and cellular levels with Western blot and immunohistochemistry. We found that Pax2-expressing cells were largely unchanged at E18 and P1, while at P7, their number was increased and maturation into parvalbumin-expressing cells delayed. Our findings indicate that, in mice, Tsc1 haploinsufficiency leads to altered cerebellar development and that cerebellar interneuron precursors are particularly susceptible to mTOR pathway dysregulation.
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Affiliation(s)
- Ines Serra
- Department of Neuroscience, Erasmus MC, Rotterdam, Netherlands
| | - Ana Stravs
- Department of Neuroscience, Erasmus MC, Rotterdam, Netherlands
- Institute of Biology Leiden, Leiden University, Leiden, Netherlands
| | - Catarina Osório
- Department of Neuroscience, Erasmus MC, Rotterdam, Netherlands
| | - Maria Roa Oyaga
- Department of Neuroscience, Erasmus MC, Rotterdam, Netherlands
| | | | | | - Aleksandra Badura
- Department of Neuroscience, Erasmus MC, Rotterdam, Netherlands
- *Correspondence: Aleksandra Badura,
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18
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Secco LP, Coubes C, Meyer P, Chenine L, Roubertie A, Malinge MC, Bessis D. Dermatological and genetic data in tuberous sclerosis: A prospective single-center study of 38 patients. Ann Dermatol Venereol 2022; 149:241-244. [PMID: 35527063 DOI: 10.1016/j.annder.2022.02.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 11/20/2021] [Accepted: 02/09/2022] [Indexed: 11/15/2022]
Abstract
BACKGROUND Tuberous sclerosis complex (TSC) is a genetic disorder involving the TSC1 or TSC2 gene. Skin signs are prominent, but dermatological data are scarce. This study aims to describe the cutaneous signs of TSC with the genotype. METHODS We studied the dermatological characteristics of 38 patients with TSC at the University Hospital of Montpellier. We collected details of genotypic features. RESULTS All the patients presented at least one cutaneous sign. The dermatological examination alone was sufficient to establish a definite diagnosis of TSC based on the diagnostic criteria for 34/38 patients. No association was found between cutaneous signs and the presence of a TSC1 or TSC2 mutation. We noted skin signs that were poorly described in the disease, namely epidermal nevus in 3 patients, vascular malformation in 2 patients, and keratosis pilaris in 9 patients. DISCUSSION While several studies demonstrate a more severe neurological phenotype in TSC2 mutated patients, skin expression does not appear to differ according to the mutated gene. Further case reports and molecular genetic studies are needed to determine the link between epidermal nevus, vascular malformations, keratosis pilaris and TSC.
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Affiliation(s)
- L-P Secco
- Department of Dermatology, Montpellier University Hospital Center, 34295 Montpellier, France.
| | - C Coubes
- Department of Genetics, Montpellier University Hospital Center, 34295 Montpellier, France
| | - P Meyer
- Department of Pediatric Neurology, Montpellier University Hospital Center, 34295 Montpellier, France
| | - L Chenine
- Department of Nephrology, Montpellier University Hospital Center, 34295 Montpellier, France
| | - A Roubertie
- Department of Pediatric Neurology, Montpellier University Hospital Center, 34295 Montpellier, France
| | - M-C Malinge
- Department of Genetics, Angers University Hospital Center, 49100 Angers, France
| | - D Bessis
- Department of Dermatology, Montpellier University Hospital Center, 34295 Montpellier, France
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19
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Weng OY, Li Y, Wang LY. Modeling Epilepsy Using Human Induced Pluripotent Stem Cells-Derived Neuronal Cultures Carrying Mutations in Ion Channels and the Mechanistic Target of Rapamycin Pathway. Front Mol Neurosci 2022; 15:810081. [PMID: 35359577 PMCID: PMC8960276 DOI: 10.3389/fnmol.2022.810081] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2021] [Accepted: 02/02/2022] [Indexed: 11/17/2022] Open
Abstract
Epilepsy is a neurological disorder that affects over 65 million people globally. It is characterized by periods of seizure activity of the brain as a result of excitation and inhibition (E/I) imbalance, which is regarded as the core underpinning of epileptic activity. Both gain- and loss-of-function (GOF and LOF) mutations of ion channels, synaptic proteins and signaling molecules along the mechanistic target of rapamycin (mTOR) pathway have been linked to this imbalance. The pathogenesis of epilepsy often has its roots in the early stage of brain development. It remains a major challenge to extrapolate the findings from many animal models carrying these GOF or LOF mutations to the understanding of disease mechanisms in the developing human brain. Recent advent of the human pluripotent stem cells (hPSCs) technology opens up a new avenue to recapitulate patient conditions and to identify druggable molecular targets. In the following review, we discuss the progress, challenges and prospects of employing hPSCs-derived neural cultures to study epilepsy. We propose a tentative working model to conceptualize the possible impact of these GOF and LOF mutations in ion channels and mTOR signaling molecules on the morphological and functional remodeling of intrinsic excitability, synaptic transmission and circuits, ultimately E/I imbalance and behavioral phenotypes in epilepsy.
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Affiliation(s)
- Octavia Yifang Weng
- Program in Developmental and Stem Cell Biology, Sick Kids Research Institutes, Toronto, ON, Canada
- Program in Neuroscience and Mental Health, Sick Kids Research Institutes, Toronto, ON, Canada
- Department of Physiology, University of Toronto, Toronto, ON, Canada
| | - Yun Li
- Program in Developmental and Stem Cell Biology, Sick Kids Research Institutes, Toronto, ON, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
- *Correspondence: Yun Li,
| | - Lu-Yang Wang
- Program in Neuroscience and Mental Health, Sick Kids Research Institutes, Toronto, ON, Canada
- Department of Physiology, University of Toronto, Toronto, ON, Canada
- Lu-Yang Wang,
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20
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Vanderplow AM, Kermath BA, Bernhardt CR, Gums KT, Seablom EN, Radcliff AB, Ewald AC, Jones MV, Baker TL, Watters JJ, Cahill ME. A feature of maternal sleep apnea during gestation causes autism-relevant neuronal and behavioral phenotypes in offspring. PLoS Biol 2022; 20:e3001502. [PMID: 35113852 PMCID: PMC8812875 DOI: 10.1371/journal.pbio.3001502] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Accepted: 11/29/2021] [Indexed: 12/26/2022] Open
Abstract
Mounting epidemiologic and scientific evidence indicates that many psychiatric disorders originate from a complex interplay between genetics and early life experiences, particularly in the womb. Despite decades of research, our understanding of the precise prenatal and perinatal experiences that increase susceptibility to neurodevelopmental disorders remains incomplete. Sleep apnea (SA) is increasingly common during pregnancy and is characterized by recurrent partial or complete cessations in breathing during sleep. SA causes pathological drops in blood oxygen levels (intermittent hypoxia, IH), often hundreds of times each night. Although SA is known to cause adverse pregnancy and neonatal outcomes, the long-term consequences of maternal SA during pregnancy on brain-based behavioral outcomes and associated neuronal functioning in the offspring remain unknown. We developed a rat model of maternal SA during pregnancy by exposing dams to IH, a hallmark feature of SA, during gestational days 10 to 21 and investigated the consequences on the offspring's forebrain synaptic structure, synaptic function, and behavioral phenotypes across multiples stages of development. Our findings represent a rare example of prenatal factors causing sexually dimorphic behavioral phenotypes associated with excessive (rather than reduced) synapse numbers and implicate hyperactivity of the mammalian target of rapamycin (mTOR) pathway in contributing to the behavioral aberrations. These findings have implications for neuropsychiatric disorders typified by superfluous synapse maintenance that are believed to result, at least in part, from largely unknown insults to the maternal environment.
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Affiliation(s)
- Amanda M. Vanderplow
- Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Bailey A. Kermath
- Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Cassandra R. Bernhardt
- Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Kimberly T. Gums
- Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Erin N. Seablom
- Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Abigail B. Radcliff
- Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Andrea C. Ewald
- Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Mathew V. Jones
- Department of Neuroscience, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Tracy L. Baker
- Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Jyoti J. Watters
- Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Michael E. Cahill
- Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
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21
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Gozzelino L, Kochlamazashvili G, Baldassari S, Mackintosh AI, Licchetta L, Iovino E, Liu YC, Bennett CA, Bennett MF, Damiano JA, Zsurka G, Marconi C, Giangregorio T, Magini P, Kuijpers M, Maritzen T, Norata GD, Baulac S, Canafoglia L, Seri M, Tinuper P, Scheffer IE, Bahlo M, Berkovic SF, Hildebrand MS, Kunz WS, Giordano L, Bisulli F, Martini M, Haucke V, Hirsch E, Pippucci T. OUP accepted manuscript. Brain 2022; 145:2313-2331. [PMID: 35786744 PMCID: PMC9337808 DOI: 10.1093/brain/awac082] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Revised: 01/13/2022] [Accepted: 02/12/2022] [Indexed: 11/20/2022] Open
Abstract
Epilepsy is one of the most frequent neurological diseases, with focal epilepsy accounting for the largest number of cases. The genetic alterations involved in focal epilepsy are far from being fully elucidated. Here, we show that defective lipid signalling caused by heterozygous ultra-rare variants in PIK3C2B, encoding for the class II phosphatidylinositol 3-kinase PI3K-C2β, underlie focal epilepsy in humans. We demonstrate that patients’ variants act as loss-of-function alleles, leading to impaired synthesis of the rare signalling lipid phosphatidylinositol 3,4-bisphosphate, resulting in mTORC1 hyperactivation. In vivo, mutant Pik3c2b alleles caused dose-dependent neuronal hyperexcitability and increased seizure susceptibility, indicating haploinsufficiency as a key driver of disease. Moreover, acute mTORC1 inhibition in mutant mice prevented experimentally induced seizures, providing a potential therapeutic option for a selective group of patients with focal epilepsy. Our findings reveal an unexpected role for class II PI3K-mediated lipid signalling in regulating mTORC1-dependent neuronal excitability in mice and humans.
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Affiliation(s)
| | | | | | - Albert Ian Mackintosh
- Department of Molecular Pharmacology and Cell Biology, Leibniz Forschungsinstitut für Molekulare Pharmakologie (FMP), Robert-Roessle-Strasse 10, 13125 Berlin, Germany
| | - Laura Licchetta
- IRCCS Istituto delle Scienze Neurologiche di Bologna, Epilepsy Center (Reference Center for Rare and Complex Epilepsies—EpiCARE), Bologna, Italy
| | - Emanuela Iovino
- Department of Medical and Surgical Sciences (DIMEC), University of Bologna, Bologna, Italy
| | - Yu Chi Liu
- Epilepsy Research Centre, Department of Medicine, University of Melbourne, Austin Health, Melbourne, Victoria, Australia
- Population Health and Immunity Division, The Walter and Eliza Hall Institute of Medical Research, Melbourne, Victoria, Australia
- Department of Medical Biology, University of Melbourne, Melbourne, VictoriaAustralia
| | - Caitlin A Bennett
- Epilepsy Research Centre, Department of Medicine, University of Melbourne, Austin Health, Melbourne, Victoria, Australia
| | - Mark F Bennett
- Epilepsy Research Centre, Department of Medicine, University of Melbourne, Austin Health, Melbourne, Victoria, Australia
- Population Health and Immunity Division, The Walter and Eliza Hall Institute of Medical Research, Melbourne, Victoria, Australia
- Department of Medical Biology, University of Melbourne, Melbourne, VictoriaAustralia
| | - John A Damiano
- Epilepsy Research Centre, Department of Medicine, University of Melbourne, Austin Health, Melbourne, Victoria, Australia
| | - Gábor Zsurka
- Department of Experimental Epileptology and Cognition Research and Department of Epileptology, University Bonn Medical Center, Venusberg Campus 1, D-53105 Bonn, Germany
| | - Caterina Marconi
- Department of Medical and Surgical Sciences (DIMEC), University of Bologna, Bologna, Italy
| | - Tania Giangregorio
- Department of Medical and Surgical Sciences (DIMEC), University of Bologna, Bologna, Italy
| | - Pamela Magini
- U.O. Genetica Medica, IRCCS Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italy
| | - Marijn Kuijpers
- Department of Molecular Pharmacology and Cell Biology, Leibniz Forschungsinstitut für Molekulare Pharmakologie (FMP), Robert-Roessle-Strasse 10, 13125 Berlin, Germany
| | - Tanja Maritzen
- Department of Molecular Pharmacology and Cell Biology, Leibniz Forschungsinstitut für Molekulare Pharmakologie (FMP), Robert-Roessle-Strasse 10, 13125 Berlin, Germany
- Department of Nanophysiology, Technische Universität Kaiserslautern, 67663 Kaiserslautern, Germany
| | - Giuseppe Danilo Norata
- Department of Excellence in Pharmacological and Biomolecular Sciences, Università degli Studi di Milano, Milan and Center for the Study of Atherosclerosis, SISA Bassini Hospital Cinisello B, Italy
| | - Stéphanie Baulac
- Sorbonne Université, Institut du Cerveau—Paris Brain Institute—ICM, Inserm, CNRS, F-75013 Paris, France
| | - Laura Canafoglia
- Unit of Integrated Diagnostics for Epilepsy, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Marco Seri
- Department of Medical and Surgical Sciences (DIMEC), University of Bologna, Bologna, Italy
- U.O. Genetica Medica, IRCCS Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italy
| | - Paolo Tinuper
- IRCCS Istituto delle Scienze Neurologiche di Bologna, Epilepsy Center (Reference Center for Rare and Complex Epilepsies—EpiCARE), Bologna, Italy
- Department of Biomedical and NeuroMotor Sciences (DIBINEM), University of Bologna, Bologna, Italy
| | - Ingrid E Scheffer
- Epilepsy Research Centre, Department of Medicine, University of Melbourne, Austin Health, Melbourne, Victoria, Australia
- Murdoch Children’s Research Institute, Royal Children’s Hospital, Parkville, Melbourne, Victoria, Australia
- Florey Institute for Neuroscience and Mental Health, University of Melbourne, Melbourne, Victoria, Australia
- Department of Pediatrics, University of Melbourne, Royal Children's Hospital, Melbourne, Victoria, Australia
| | - Melanie Bahlo
- Spedali Civili, Neuropsychiatric Department, Brescia, Italy
- Faculty of Biology, Chemistry, Pharmacy, Freie Universität Berlin, 14195 Berlin, Germany
| | - Samuel F Berkovic
- Epilepsy Research Centre, Department of Medicine, University of Melbourne, Austin Health, Melbourne, Victoria, Australia
| | - Michael S Hildebrand
- Epilepsy Research Centre, Department of Medicine, University of Melbourne, Austin Health, Melbourne, Victoria, Australia
- Murdoch Children’s Research Institute, Royal Children’s Hospital, Parkville, Melbourne, Victoria, Australia
| | - Wolfram S Kunz
- Department of Experimental Epileptology and Cognition Research and Department of Epileptology, University Bonn Medical Center, Venusberg Campus 1, D-53105 Bonn, Germany
| | - Lucio Giordano
- Spedali Civili, Neuropsychiatric Department, Brescia, Italy
| | - Francesca Bisulli
- IRCCS Istituto delle Scienze Neurologiche di Bologna, Epilepsy Center (Reference Center for Rare and Complex Epilepsies—EpiCARE), Bologna, Italy
- Department of Biomedical and NeuroMotor Sciences (DIBINEM), University of Bologna, Bologna, Italy
| | | | - Volker Haucke
- Volker Haucke Robert-Roessle-Strasse 10, 13125 Berlin, Germany E-mail:
| | - Emilio Hirsch
- Correspondence may also be addressed to: Emilio Hirsch via Nizza 52, 10126 Torino (TO), Italy E-mail:
| | - Tommaso Pippucci
- Correspondence to: Tommaso Pippucci Via Giuseppe Massarenti 9, 40138 Bologna (BO), Italy E-mail:
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22
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Overexpression of Lin28A in neural progenitor cells in vivo does not lead to brain tumor formation but results in reduced spine density. Acta Neuropathol Commun 2021; 9:185. [PMID: 34801069 PMCID: PMC8606090 DOI: 10.1186/s40478-021-01289-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Accepted: 11/02/2021] [Indexed: 11/10/2022] Open
Abstract
LIN28A overexpression has been identified in malignant brain tumors called embryonal tumors with multilayered rosettes (ETMR) but its specific role during brain development remains largely unknown. Radial glia cells of the ventricular zone (VZ) are proposed as a cell of origin for ETMR. We asked whether an overexpression of LIN28A in such cells might affect brain development or result in the formation of brain tumors.Constitutive overexpression of LIN28A in hGFAP-cre::lsl-Lin28A (GL) mice led to a transient increase of proliferation in the cortical VZ at embryonic stages but no postnatal brain tumor formation. Postnatally, GL mice displayed a pyramidal cell layer dispersion of the hippocampus and altered spine and dendrite morphology, including reduced dendritic spine densities in the hippocampus and cortex. GL mice displayed hyperkinetic activity and differential quantitative MS-based proteomics revealed altered time dependent molecular functions regarding mRNA processing and spine morphogenesis. Phosphoproteomic analyses indicated a downregulation of mTOR pathway modulated proteins such as Map1b being involved in microtubule dynamics.In conclusion, we show that Lin28A overexpression transiently increases proliferation of neural precursor cells but it is not sufficient to drive brain tumors in vivo. In contrast, Lin28A impacts on protein abundancy patterns related to spine morphogenesis and phosphorylation levels of proteins involved in microtubule dynamics, resulting in decreased spine densities of neurons in the hippocampus and cortex as well as in altered behavior. Our work provides new insights into the role of LIN28A for neuronal morphogenesis and development and may reveal future targets for treatment of ETMR patients.
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23
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Moloney PB, Cavalleri GL, Delanty N. Epilepsy in the mTORopathies: opportunities for precision medicine. Brain Commun 2021; 3:fcab222. [PMID: 34632383 PMCID: PMC8495134 DOI: 10.1093/braincomms/fcab222] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 08/23/2021] [Accepted: 08/30/2021] [Indexed: 01/16/2023] Open
Abstract
The mechanistic target of rapamycin signalling pathway serves as a ubiquitous regulator of cell metabolism, growth, proliferation and survival. The main cellular activity of the mechanistic target of rapamycin cascade funnels through mechanistic target of rapamycin complex 1, which is inhibited by rapamycin, a macrolide compound produced by the bacterium Streptomyces hygroscopicus. Pathogenic variants in genes encoding upstream regulators of mechanistic target of rapamycin complex 1 cause epilepsies and neurodevelopmental disorders. Tuberous sclerosis complex is a multisystem disorder caused by mutations in mechanistic target of rapamycin regulators TSC1 or TSC2, with prominent neurological manifestations including epilepsy, focal cortical dysplasia and neuropsychiatric disorders. Focal cortical dysplasia type II results from somatic brain mutations in mechanistic target of rapamycin pathway activators MTOR, AKT3, PIK3CA and RHEB and is a major cause of drug-resistant epilepsy. DEPDC5, NPRL2 and NPRL3 code for subunits of the GTPase-activating protein (GAP) activity towards Rags 1 complex (GATOR1), the principal amino acid-sensing regulator of mechanistic target of rapamycin complex 1. Germline pathogenic variants in GATOR1 genes cause non-lesional focal epilepsies and epilepsies associated with malformations of cortical development. Collectively, the mTORopathies are characterized by excessive mechanistic target of rapamycin pathway activation and drug-resistant epilepsy. In the first large-scale precision medicine trial in a genetically mediated epilepsy, everolimus (a synthetic analogue of rapamycin) was effective at reducing seizure frequency in people with tuberous sclerosis complex. Rapamycin reduced seizures in rodent models of DEPDC5-related epilepsy and focal cortical dysplasia type II. This review outlines a personalized medicine approach to the management of epilepsies in the mTORopathies. We advocate for early diagnostic sequencing of mechanistic target of rapamycin pathway genes in drug-resistant epilepsy, as identification of a pathogenic variant may point to an occult dysplasia in apparently non-lesional epilepsy or may uncover important prognostic information including, an increased risk of sudden unexpected death in epilepsy in the GATORopathies or favourable epilepsy surgery outcomes in focal cortical dysplasia type II due to somatic brain mutations. Lastly, we discuss the potential therapeutic application of mechanistic target of rapamycin inhibitors for drug-resistant seizures in GATOR1-related epilepsies and focal cortical dysplasia type II.
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Affiliation(s)
- Patrick B Moloney
- FutureNeuro, the Science Foundation Ireland Research Centre for Chronic and Rare Neurological Diseases, Royal College of Surgeons in Ireland, Dublin, D02 VN51, Ireland
| | - Gianpiero L Cavalleri
- FutureNeuro, the Science Foundation Ireland Research Centre for Chronic and Rare Neurological Diseases, Royal College of Surgeons in Ireland, Dublin, D02 VN51, Ireland
| | - Norman Delanty
- FutureNeuro, the Science Foundation Ireland Research Centre for Chronic and Rare Neurological Diseases, Royal College of Surgeons in Ireland, Dublin, D02 VN51, Ireland
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24
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Ihnen SKZ, Capal JK, Horn PS, Griffith M, Sahin M, Martina Bebin E, Wu JY, Northrup H, Krueger DA. Epilepsy Is Heterogeneous in Early-Life Tuberous Sclerosis Complex. Pediatr Neurol 2021; 123:1-9. [PMID: 34343869 PMCID: PMC8487620 DOI: 10.1016/j.pediatrneurol.2021.06.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Revised: 06/28/2021] [Accepted: 06/29/2021] [Indexed: 11/24/2022]
Abstract
BACKGROUND Epilepsy in tuberous sclerosis complex (TSC) typically presents with early onset, multiple seizure types, and intractability. However, variability is observed among individuals. Here, detailed individual data on seizure characteristics collected prospectively during early life were used to define epilepsy profiles in this population. METHODS Children aged zero to 36 months were followed longitudinally. Caregivers kept daily seizure diaries, including onset and daily counts for each seizure type. Patients with >70% seizure diary completion and >365 diary days were included. Developmental outcomes at 36 months were compared between subgroups. RESULTS Epilepsy was seen in 124 of 156 (79%) participants. Seizure onset occurred from zero to 29.5 months; 93% had onset before age 12 months. Focal seizures and epileptic spasms were most common. Number of seizures (for median 897 days) ranged from 1 to 9128. Hierarchical clustering based on six metrics of seizure burden (age of onset, total seizures, ratio of seizure days to nonseizure days, seizures per seizure day, and worst seven- and 30-day stretches) revealed two distinct groups with broadly favorable and unfavorable epilepsy profiles. Subpopulations within each group showed clinically meaningful differences in seizure burden. Groups with higher seizure burden had worse developmental outcomes at 36 months. CONCLUSIONS Although epilepsy is highly prevalent in TSC, not all young children with TSC have the same epilepsy profile. At least two phenotypic subpopulations are discernible based on seizure burden. Early and aggressive treatments for epilepsy in TSC may be best leveraged by targeting specific subgroups based on phenotype severity.
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Affiliation(s)
- S. Katie Z. Ihnen
- Division of Neurology, Cincinnati Children’s Hospital Medical Center, Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
| | - Jamie K. Capal
- Department of Neurology, University of North Carolina at Chapel Hill, Chapel Hill, NC
| | - Paul S. Horn
- Division of Neurology, Cincinnati Children’s Hospital Medical Center, Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
| | - Molly Griffith
- Division of Neurology, Cincinnati Children’s Hospital Medical Center, Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
| | - Mustafa Sahin
- Department of Neurology and F.M Kirby Neurobiology Center, Boston Children’s Hospital, Harvard Medical School, Harvard University, Boston, MA
| | - E. Martina Bebin
- Department of Neurology, University of Alabama at Birmingham, Birmingham, AL
| | - Joyce Y. Wu
- Division of Neurology, Department of Pediatrics, Ann & Robert H. Lurie Children’s Hospital of Chicago, Northwestern University Feinberg School of Medicine, Chicago, IL
| | - Hope Northrup
- Department of Pediatrics, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX
| | - Darcy A. Krueger
- Division of Neurology, Cincinnati Children’s Hospital Medical Center, Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
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25
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Tuberous Sclerosis Complex (TSC) Inactivation Increases Neuronal Network Activity by Enhancing Ca 2+ Influx via L-Type Ca 2+ Channels. J Neurosci 2021; 41:8134-8149. [PMID: 34417327 DOI: 10.1523/jneurosci.1930-20.2021] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 08/09/2021] [Accepted: 08/11/2021] [Indexed: 12/19/2022] Open
Abstract
Tuberous sclerosis complex (TSC) is a multisystem developmental disorder characterized by hamartomas in various organs, such as the brain, lungs, and kidneys. Epilepsy, along with autism and intellectual disability, is one of the neurologic impairments associated with TSC that has an intimate relationship with developmental outcomes and quality of life. Sustained activation of the mammalian target of rapamycin (mTOR) via TSC1 or TSC2 mutations is known to be involved in the onset of epilepsy in TSC. However, the mechanism by which mTOR causes seizures remains unknown. In this study, we showed that, human induced pluripotent stem cell-derived TSC2-deficient (TSC2 -/-) neurons exhibited elevated neuronal activity with highly synchronized Ca2+ spikes. Notably, TSC2 -/- neurons presented enhanced Ca2+ influx via L-type Ca2+ channels (LTCCs), which contributed to the abnormal neurite extension and sustained activation of cAMP response element binding protein (CREB), a critical mediator of synaptic plasticity. Expression of Cav1.3, a subtype of LTCCs, was increased in TSC2 -/- neurons, but long-term rapamycin treatment suppressed this increase and reversed the altered neuronal activity and neurite extensions. Thus, we identified Cav1.3 LTCC as a critical downstream component of TSC-mTOR signaling that would trigger enhanced neuronal network activity of TSC2 -/- neurons. We suggest that LTCCs could be potential novel targets for the treatment of epilepsy in TSC.SIGNIFICANCE STATEMENT There is a close relationship between elevated mammalian target of rapamycin (mTOR) activity and epilepsy in tuberous sclerosis complex (TSC). However, the underlying mechanism by which mTOR causes epilepsy remains unknown. In this study, using human TSC2 -/- neurons, we identified elevated Ca2+ influx via L-type Ca2+ channels as a critical downstream component of TSC-mTOR signaling and a potential cause of both elevated neuronal activity and neurite extension in TSC2 -/- neurons. Our findings demonstrate a previously unrecognized connection between sustained mTOR activation and elevated Ca2+ signaling via L-type Ca2+ channels in human TSC neurons, which could cause epilepsy in TSC.
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26
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Sato A, Ikeda K. Genetic and Environmental Contributions to Autism Spectrum Disorder Through Mechanistic Target of Rapamycin. BIOLOGICAL PSYCHIATRY GLOBAL OPEN SCIENCE 2021; 2:95-105. [PMID: 36325164 PMCID: PMC9616270 DOI: 10.1016/j.bpsgos.2021.08.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Revised: 08/17/2021] [Accepted: 08/18/2021] [Indexed: 02/06/2023] Open
Abstract
Autism spectrum disorder (ASD) is a neurodevelopmental disorder that affects an individual’s reciprocal social interaction and communication ability. Numerous genetic and environmental conditions are associated with ASD, including tuberous sclerosis complex, phosphatase and tensin homolog hamartoma tumor syndrome, fragile X syndrome, and neurofibromatosis 1. The pathogenic molecular mechanisms of these diseases are integrated into the hyperactivation of mTORC1 (mechanistic target of rapamycin complex 1). Rodent models of these diseases have shown high mTORC1 activity in the brain and ASD-related behavioral deficits, which were reversed by the mTORC1 inhibitor rapamycin. Environmental stress can also affect this signaling pathway. In utero exposure to valproate caused ASD in offspring and enhanced mTORC1 activity in the brain, which was sensitive to mTORC1 inhibition. mTORC1 is a signaling hub for diverse cellular functions, including protein synthesis, through the phosphorylation of its targets, such as ribosomal protein S6 kinases. Metabotropic glutamate receptor 5–mediated synaptic function is also affected by the dysregulation of mTORC1 activity, such as in fragile X syndrome and tuberous sclerosis complex. Reversing these downstream changes that are associated with mTORC1 activation normalizes behavioral defects in rodents. Despite abundant preclinical evidence, few clinical studies have investigated the treatment of ASD and cognitive deficits. Therapeutics other than mTORC1 inhibitors failed to show efficacy in fragile X syndrome and neurofibromatosis 1. mTORC1 inhibitors have been tested mainly in tuberous sclerosis complex, and their effects on ASD and neuropsychological deficits are promising. mTORC1 is a promising target for the pharmacological treatment of ASD associated with mTORC1 activation.
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27
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Klofas LK, Short BP, Zhou C, Carson RP. Prevention of premature death and seizures in a Depdc5 mouse epilepsy model through inhibition of mTORC1. Hum Mol Genet 2021; 29:1365-1377. [PMID: 32280987 DOI: 10.1093/hmg/ddaa068] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Revised: 03/31/2020] [Accepted: 04/06/2020] [Indexed: 11/13/2022] Open
Abstract
Mutations in DEP domain containing 5 (DEPDC5) are increasingly appreciated as one of the most common causes of inherited focal epilepsy. Epilepsies due to DEPDC5 mutations are often associated with brain malformations, tend to be drug-resistant, and have been linked to an increased risk of sudden unexplained death in epilepsy (SUDEP). Generation of epilepsy models to define mechanisms of epileptogenesis remains vital for future therapies. Here, we describe a novel mouse model of Depdc5 deficiency with a severe epilepsy phenotype, generated by conditional deletion of Depdc5 in dorsal telencephalic neuroprogenitor cells. In contrast to control and heterozygous mice, Depdc5-Emx1-Cre conditional knockout (CKO) mice demonstrated macrocephaly, spontaneous seizures and premature death. Consistent with increased mTORC1 activation, targeted neurons were enlarged and both neurons and astrocytes demonstrated increased S6 phosphorylation. Electrophysiologic characterization of miniature inhibitory post-synaptic currents in excitatory neurons was consistent with impaired post-synaptic response to GABAergic input, suggesting a potential mechanism for neuronal hyperexcitability. mTORC1 inhibition with rapamycin significantly improved survival of CKO animals and prevented observed seizures, including for up to 40 days following rapamycin withdrawal. These data not only support a primary role for mTORC1 hyperactivation in epilepsy following homozygous loss of Depdc5, but also suggest a developmental window for treatment which may have a durable benefit for some time even after withdrawal.
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Affiliation(s)
- Lindsay K Klofas
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN 37232, USA
| | - Brittany P Short
- Division of Pediatric Neurology, Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Chengwen Zhou
- Department of Neurology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Robert P Carson
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN 37232, USA.,Division of Pediatric Neurology, Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN 37232, USA.,Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
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28
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Boksha IS, Prokhorova TA, Tereshkina EB, Savushkina OK, Burbaeva GS. Protein Phosphorylation Signaling Cascades in Autism: The Role of mTOR Pathway. BIOCHEMISTRY (MOSCOW) 2021; 86:577-596. [PMID: 33993859 DOI: 10.1134/s0006297921050072] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The mammalian target of rapamycin (mTOR) signaling pathway is a central regulator of cell metabolism, growth, and survival in response to hormones, growth factors, nutrients, and stress-induced signals. In this review, we analyzed the studies on the molecular abnormalities of the mTOR-associated signaling cascades in autism spectrum disorders (ASDs) and outlined the prospects for the pathogenicity-targeting pharmacotherapeutic approaches to ASDs, in particular syndromic ASDs. Based on available experimental and clinical data, we suggest that very early detection of molecular abnormalities in the ASD risk groups can be facilitated by using peripheral blood platelets. Also, identification of the time window of critical dysregulations in the described pathways in the ASD risk groups might suggest further research directions leading to more efficacious pharmacotherapeutic interventions in ASDs.
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Affiliation(s)
- Irina S Boksha
- Mental Health Research Center, Moscow, 115522, Russia. .,Gamaleya Research Center of Epidemiology and Microbiology, Ministry of Health of the Russian Federation, Moscow, 123098, Russia
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29
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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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30
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D'Gama AM, Poduri A. Precision Therapy for Epilepsy Related to Brain Malformations. Neurotherapeutics 2021; 18:1548-1563. [PMID: 34608615 PMCID: PMC8608994 DOI: 10.1007/s13311-021-01122-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/04/2021] [Indexed: 02/04/2023] Open
Abstract
Malformations of cortical development (MCDs) represent a range of neurodevelopmental disorders that are collectively common causes of developmental delay and epilepsy, especially refractory childhood epilepsy. Initial treatment with antiseizure medications is empiric, and consideration of surgery is the standard of care for eligible patients with medically refractory epilepsy. In the past decade, advances in next generation sequencing technologies have accelerated progress in understanding the genetic etiologies of MCDs, and precision therapies for focal MCDs are emerging. Notably, mutations that lead to abnormal activation of the mammalian target of rapamycin (mTOR) pathway, which provides critical control of cell growth and proliferation, have emerged as a common cause of malformations. These include tuberous sclerosis complex (TSC), hemimegalencephaly (HME), and some types of focal cortical dysplasia (FCD). TSC currently represents the best example for the pathway from gene discovery to relatively safe and efficacious targeted therapy for epilepsy related to MCDs. Based on extensive pre-clinical and clinical data, the mTOR inhibitor everolimus is currently approved for the treatment of focal refractory seizures in patients with TSC. Although clinical studies are just emerging for FCD and HME, we believe the next decade will bring significant advancements in precision therapies for epilepsy related to these and other MCDs.
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Affiliation(s)
- Alissa M D'Gama
- Divisions of Newborn Medicine and Genetics and Genomics, Department of Pediatrics, Boston Children's Hospital, Boston, MA, USA
- Epilepsy Genetics Program, Department of Neurology, Boston Children's Hospital, Boston, MA, USA
- Departments of Neurology and Pediatrics, Harvard Medical School, Boston, MA, USA
- Broad Institute of Harvard and MIT, Cambridge, MA, USA
| | - Annapurna Poduri
- Epilepsy Genetics Program, Department of Neurology, Boston Children's Hospital, Boston, MA, USA.
- Departments of Neurology and Pediatrics, Harvard Medical School, Boston, MA, USA.
- Broad Institute of Harvard and MIT, Cambridge, MA, USA.
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31
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Kumar P, Zadjali F, Yao Y, Siroky B, Astrinidis A, Gross KW, Bissler JJ. Tsc Gene Locus Disruption and Differences in Renal Epithelial Extracellular Vesicles. Front Physiol 2021; 12:630933. [PMID: 34262466 PMCID: PMC8273388 DOI: 10.3389/fphys.2021.630933] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Accepted: 03/29/2021] [Indexed: 12/31/2022] Open
Abstract
In tuberous sclerosis complex (TSC), Tsc2 mutations are associated with more severe disease manifestations than Tsc1 mutations and the role of extracellular vesicles (EVs) in this context is not yet studied. We report a comparative analysis of EVs derived from isogenic renal cells except for Tsc1 or Tsc2 gene status and hypothesized that in spite of having similar physical characteristics, EVs modulate signaling pathways differently, thus leading to TSC heterogenicity. We used mouse inner medullary collecting duct (mIMCD3) cells with the Tsc1 (T1G cells) or Tsc2 (T2J cells) gene disrupted by CRISPR/CAS9. EVs were isolated from the cell culture media by size-exclusion column chromatography followed by detailed physical and chemical characterization. Physical characterization of EVs was accessed by tunable resistive pulse sensing and dynamic light scattering, revealing similar average sizes and zeta potentials (at pH 7.4) for EVs from mIMCD3 (123.5 ± 5.7 nm and −16.3 ± 2.1 mV), T1G cells (131.5 ± 8.3 nm and −19.8 ± 2.7 mV), and T2J cells (127.3 ± 4.9 nm and −20.2 ± 2.1 mV). EVs derived from parental mIMCD3 cells and both mutated cell lines were heterogeneous (>90% of EVs < 150 nm) in nature. Immunoblotting detected cilial Hedgehog signaling protein Arl13b; intercellular proteins TSG101 and Alix; and transmembrane proteins CD63, CD9, and CD81. Compared to Tsc2 deletion, Tsc1 deletion cells had reduced EV production and release rates. EVs from Tsc1 mutant cells altered mTORC1, autophagy, and β-catenin pathways differently than EVs from Tsc2-mutated cells. Quantitative PCR analysis revealed the down regulation of miR-212a-3p and miR-99a-5p in EVs from Tsc2-mutated cells compared to EVs from Tsc1-mutant cells. Thus, EV-derived miR-212-3p and mIR-99a-5p axes may represent therapeutic targets or biomarkers for TSC disease.
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Affiliation(s)
- Prashant Kumar
- Department of Pediatrics, University of Tennessee Health Science Center and Le Bonheur Children's Hospital, Memphis, TN, United States
| | - Fahad Zadjali
- Department of Pediatrics, University of Tennessee Health Science Center and Le Bonheur Children's Hospital, Memphis, TN, United States.,Department of Clinical Biochemistry, College of Medicine & Health Sciences, Sultan Qaboos University, Muscat, Oman
| | - Ying Yao
- Department of Pediatrics, University of Tennessee Health Science Center and Le Bonheur Children's Hospital, Memphis, TN, United States
| | - Brian Siroky
- Department of Pediatrics, University of Tennessee Health Science Center and Le Bonheur Children's Hospital, Memphis, TN, United States
| | - Aristotelis Astrinidis
- Department of Pediatrics, University of Tennessee Health Science Center and Le Bonheur Children's Hospital, Memphis, TN, United States
| | - Kenneth W Gross
- Department of Molecular and Cellular Biology, Roswell Park Comprehensive Cancer Center, Buffalo, NY, United States
| | - John J Bissler
- Department of Pediatrics, University of Tennessee Health Science Center and Le Bonheur Children's Hospital, Memphis, TN, United States.,Department of Pediatrics, St. Jude Children's Research Hospital, Memphis, TN, United States
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32
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Li RA, Talikka M, Gubian S, Vom Berg C, Martin F, Peitsch MC, Hoeng J, Zupanic A. Systems Toxicology Approach for Assessing Developmental Neurotoxicity in Larval Zebrafish. Front Genet 2021; 12:652632. [PMID: 34211495 PMCID: PMC8239408 DOI: 10.3389/fgene.2021.652632] [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: 01/12/2021] [Accepted: 05/20/2021] [Indexed: 11/13/2022] Open
Abstract
Adverse outcomes that result from chemical toxicity are rarely caused by dysregulation of individual proteins; rather, they are often caused by system-level perturbations in networks of molecular events. To fully understand the mechanisms of toxicity, it is necessary to recognize the interactions of molecules, pathways, and biological processes within these networks. The developing brain is a prime example of an extremely complex network, which makes developmental neurotoxicity one of the most challenging areas in toxicology. We have developed a systems toxicology method that uses a computable biological network to represent molecular interactions in the developing brain of zebrafish larvae. The network is curated from scientific literature and describes interactions between biological processes, signaling pathways, and adverse outcomes associated with neurotoxicity. This allows us to identify important signaling hubs, pathway interactions, and emergent adverse outcomes, providing a more complete understanding of neurotoxicity. Here, we describe the construction of a zebrafish developmental neurotoxicity network and its validation by integration with publicly available neurotoxicity-related transcriptomic datasets. Our network analysis identified consistent regulation of tumor suppressors p53 and retinoblastoma 1 (Rb1) as well as the oncogene Krüppel-like factor (Klf8) in response to chemically induced developmental neurotoxicity. The developed network can be used to interpret transcriptomic data in a neurotoxicological context.
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Affiliation(s)
- Roman A Li
- Eawag, Dübendorf, Switzerland.,PMI R&D, Philip Morris Products S.A., Neuchâtel, Switzerland
| | - Marja Talikka
- PMI R&D, Philip Morris Products S.A., Neuchâtel, Switzerland
| | - Sylvain Gubian
- PMI R&D, Philip Morris Products S.A., Neuchâtel, Switzerland
| | | | - Florian Martin
- PMI R&D, Philip Morris Products S.A., Neuchâtel, Switzerland
| | | | - Julia Hoeng
- PMI R&D, Philip Morris Products S.A., Neuchâtel, Switzerland
| | - Anze Zupanic
- Eawag, Dübendorf, Switzerland.,National Institute of Biology, Ljubljana, Slovenia
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33
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HK2 Mediated Glycolytic Metabolism in Mouse Photoreceptors Is Not Required to Cause Late Stage Age-Related Macular Degeneration-Like Pathologies. Biomolecules 2021; 11:biom11060871. [PMID: 34208233 PMCID: PMC8230848 DOI: 10.3390/biom11060871] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Revised: 06/01/2021] [Accepted: 06/09/2021] [Indexed: 12/12/2022] Open
Abstract
Age-related macular degeneration (AMD) is a multifactorial disease of unclear etiology. We previously proposed that metabolic adaptations in photoreceptors (PRs) play a role in disease progression. We mimicked these metabolic adaptations in mouse PRs through deletion of the tuberous sclerosis complex (TSC) protein TSC1. Here, we confirm our previous findings by deletion of the other complex protein, namely TSC2, in rod photoreceptors. Similar to deletion of Tsc1, mice with deletion of Tsc2 in rods develop AMD-like pathologies, including accumulation of apolipoproteins, migration of microglia, geographic atrophy, and neovascular pathologies. Subtle differences between the two mouse models, such as a significant increase in microglia activation with loss of Tsc2, were seen as well. To investigate the role of altered glucose metabolism in disease pathogenesis, we generated mice with simulation deletions of Tsc2 and hexokinase-2 (Hk2) in rods. Although retinal lactate levels returned to normal in mice with Tsc2-Hk2 deletion, AMD-like pathologies still developed. The data suggest that the metabolic adaptations in PRs that cause AMD-like pathologies are independent of HK2-mediated aerobic glycolysis.
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Davogustto GE, Salazar RL, Vasquez HG, Karlstaedt A, Dillon WP, Guthrie PH, Martin JR, Vitrac H, De La Guardia G, Vela D, Ribas-Latre A, Baumgartner C, Eckel-Mahan K, Taegtmeyer H. Metabolic remodeling precedes mTORC1-mediated cardiac hypertrophy. J Mol Cell Cardiol 2021; 158:115-127. [PMID: 34081952 DOI: 10.1016/j.yjmcc.2021.05.016] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 05/21/2021] [Accepted: 05/26/2021] [Indexed: 11/17/2022]
Abstract
RATIONALE The nutrient sensing mechanistic target of rapamycin complex 1 (mTORC1) and its primary inhibitor, tuberin (TSC2), are cues for the development of cardiac hypertrophy. The phenotype of mTORC1 induced hypertrophy is unknown. OBJECTIVE To examine the impact of sustained mTORC1 activation on metabolism, function, and structure of the adult heart. METHODS AND RESULTS We developed a mouse model of inducible, cardiac-specific sustained mTORC1 activation (mTORC1iSA) through deletion of Tsc2. Prior to hypertrophy, rates of glucose uptake and oxidation, as well as protein and enzymatic activity of glucose 6-phosphate isomerase (GPI) were decreased, while intracellular levels of glucose 6-phosphate (G6P) were increased. Subsequently, hypertrophy developed. Transcript levels of the fetal gene program and pathways of exercise-induced hypertrophy increased, while hypertrophy did not progress to heart failure. We therefore examined the hearts of wild-type mice subjected to voluntary physical activity and observed early changes in GPI, followed by hypertrophy. Rapamycin prevented these changes in both models. CONCLUSION Activation of mTORC1 in the adult heart triggers the development of a non-specific form of hypertrophy which is preceded by changes in cardiac glucose metabolism.
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Affiliation(s)
- Giovanni E Davogustto
- Division of Cardiology, Department of Internal Medicine, McGovern Medical School at The University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Rebecca L Salazar
- Division of Cardiology, Department of Internal Medicine, McGovern Medical School at The University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Hernan G Vasquez
- Division of Cardiology, Department of Internal Medicine, McGovern Medical School at The University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Anja Karlstaedt
- Division of Cardiology, Department of Internal Medicine, McGovern Medical School at The University of Texas Health Science Center at Houston, Houston, TX, USA
| | - William P Dillon
- Division of Cardiology, Department of Internal Medicine, McGovern Medical School at The University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Patrick H Guthrie
- Division of Cardiology, Department of Internal Medicine, McGovern Medical School at The University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Joseph R Martin
- Division of Cardiology, Department of Internal Medicine, McGovern Medical School at The University of Texas Health Science Center at Houston, Houston, TX, USA
| | | | - Gina De La Guardia
- Division of Cardiology, Department of Internal Medicine, McGovern Medical School at The University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Deborah Vela
- Cardiovascular Pathology Research Laboratory, Texas Heart Institute at CHI St. Luke's Health, and the Department of Pathology and Laboratory Medicine, The University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Aleix Ribas-Latre
- Center for Metabolic and Degenerative Diseases, Institute of Molecular Medicine, The University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Corrine Baumgartner
- Center for Metabolic and Degenerative Diseases, Institute of Molecular Medicine, The University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Kristin Eckel-Mahan
- Center for Metabolic and Degenerative Diseases, Institute of Molecular Medicine, The University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Heinrich Taegtmeyer
- Division of Cardiology, Department of Internal Medicine, McGovern Medical School at The University of Texas Health Science Center at Houston, Houston, TX, USA.
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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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The Kainic Acid Models of Temporal Lobe Epilepsy. eNeuro 2021; 8:ENEURO.0337-20.2021. [PMID: 33658312 PMCID: PMC8174050 DOI: 10.1523/eneuro.0337-20.2021] [Citation(s) in RCA: 74] [Impact Index Per Article: 24.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 01/14/2021] [Accepted: 01/24/2021] [Indexed: 12/14/2022] Open
Abstract
Experimental models of epilepsy are useful to identify potential mechanisms of epileptogenesis, seizure genesis, comorbidities, and treatment efficacy. The kainic acid (KA) model is one of the most commonly used. Several modes of administration of KA exist, each producing different effects in a strain-, species-, gender-, and age-dependent manner. In this review, we discuss the advantages and limitations of the various forms of KA administration (systemic, intrahippocampal, and intranasal), as well as the histologic, electrophysiological, and behavioral outcomes in different strains and species. We attempt a personal perspective and discuss areas where work is needed. The diversity of KA models and their outcomes offers researchers a rich palette of phenotypes, which may be relevant to specific traits found in patients with temporal lobe epilepsy.
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4E-BP2-dependent translation in parvalbumin neurons controls epileptic seizure threshold. Proc Natl Acad Sci U S A 2021; 118:2025522118. [PMID: 33876772 DOI: 10.1073/pnas.2025522118] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The mechanistic/mammalian target of rapamycin complex 1 (mTORC1) integrates multiple signals to regulate critical cellular processes such as mRNA translation, lipid biogenesis, and autophagy. Germline and somatic mutations in mTOR and genes upstream of mTORC1, such as PTEN, TSC1/2, AKT3, PIK3CA, and components of GATOR1 and KICSTOR complexes, are associated with various epileptic disorders. Increased mTORC1 activity is linked to the pathophysiology of epilepsy in both humans and animal models, and mTORC1 inhibition suppresses epileptogenesis in humans with tuberous sclerosis and animal models with elevated mTORC1 activity. However, the role of mTORC1-dependent translation and the neuronal cell types mediating the effect of enhanced mTORC1 activity in seizures remain unknown. The eukaryotic translation initiation factor 4E-binding protein 1 (4E-BP1) and 2 (4E-BP2) are translational repressors downstream of mTORC1. Here we show that the ablation of 4E-BP2, but not 4E-BP1, in mice increases the sensitivity to pentylenetetrazole (PTZ)- and kainic acid (KA)-induced seizures. We demonstrate that the deletion of 4E-BP2 in inhibitory, but not excitatory neurons, causes an increase in the susceptibility to PTZ-induced seizures. Moreover, mice lacking 4E-BP2 in parvalbumin, but not somatostatin or VIP inhibitory neurons exhibit a lowered threshold for seizure induction and reduced number of parvalbumin neurons. A mouse model harboring a human PIK3CA mutation that enhances the activity of the PI3K-AKT pathway (Pik3ca H1047R-Pvalb ) selectively in parvalbumin neurons shows susceptibility to PTZ-induced seizures. Our data identify 4E-BP2 as a regulator of epileptogenesis and highlight the central role of increased mTORC1-dependent translation in parvalbumin neurons in the pathophysiology of epilepsy.
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Kútna V, O'Leary VB, Newman E, Hoschl C, Ovsepian SV. Revisiting Brain Tuberous Sclerosis Complex in Rat and Human: Shared Molecular and Cellular Pathology Leads to Distinct Neurophysiological and Behavioral Phenotypes. Neurotherapeutics 2021; 18:845-858. [PMID: 33398801 PMCID: PMC8423952 DOI: 10.1007/s13311-020-01000-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/21/2020] [Indexed: 12/27/2022] Open
Abstract
Tuberous sclerosis complex (TSC) is a dominant autosomal genetic disorder caused by loss-of-function mutations in TSC1 and TSC2, which lead to constitutive activation of the mammalian target of rapamycin C1 (mTORC1) with its decoupling from regulatory inputs. Because mTORC1 integrates an array of molecular signals controlling protein synthesis and energy metabolism, its unrestrained activation inflates cell growth and division, resulting in the development of benign tumors in the brain and other organs. In humans, brain malformations typically manifest through a range of neuropsychiatric symptoms, among which mental retardation, intellectual disabilities with signs of autism, and refractory seizures, which are the most prominent. TSC in the rat brain presents the first-rate approximation of cellular and molecular pathology of the human brain, showing many instructive characteristics. Nevertheless, the developmental profile and distribution of lesions in the rat brain, with neurophysiological and behavioral manifestation, deviate considerably from humans, raising numerous research and translational questions. In this study, we revisit brain TSC in human and Eker rats to relate their histopathological, electrophysiological, and neurobehavioral characteristics. We discuss shared and distinct aspects of the pathology and consider factors contributing to phenotypic discrepancies. Given the shared genetic cause and molecular pathology, phenotypic deviations suggest an incomplete understanding of the disease. Narrowing the knowledge gap in the future should not only improve the characterization of the TSC rat model but also explain considerable variability in the clinical manifestation of the disease in humans.
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Affiliation(s)
- Viera Kútna
- Department of Experimental Neurobiology, National Institute of Mental Health, Topolová 748, 250 67, Klecany, Czech Republic.
| | - Valerie B O'Leary
- Department of Medical Genetics, Third Faculty of Medicine of Charles University, Ruská 87, 100 00, Prague, Czech Republic
| | - Ehren Newman
- Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN, USA
| | - Cyril Hoschl
- Department of Experimental Neurobiology, National Institute of Mental Health, Topolová 748, 250 67, Klecany, Czech Republic
- Department of Psychiatry and Medical Psychology, Third Faculty of Medicine of Charles University, Ruská 87, 100 00, Prague, Czech Republic
| | - Saak V Ovsepian
- Department of Experimental Neurobiology, National Institute of Mental Health, Topolová 748, 250 67, Klecany, Czech Republic.
- Department of Psychiatry and Medical Psychology, Third Faculty of Medicine of Charles University, Ruská 87, 100 00, Prague, Czech Republic.
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Yang X, Zhang X, Ma Y, Wang Z, Huang K, Liu G, Shen K, Zhu G, Wang T, Lv S, Zhang C, Yang H, Liu S. Abnormal Rat Cortical Development Induced by Ventricular Injection of rHMGB1 Mimics the Pathophysiology of Human Cortical Dysplasia. Front Cell Dev Biol 2021; 9:634405. [PMID: 33748118 PMCID: PMC7969805 DOI: 10.3389/fcell.2021.634405] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Accepted: 02/12/2021] [Indexed: 11/17/2022] Open
Abstract
Cortical dysplasia (CD) is a common cause of drug-resistant epilepsy. Increasing studies have implicated innate immunity in CD with epilepsy. However, it is unclear whether innate immune factors induce epileptogenic CD. Here, we injected recombinant human high mobility group box 1 (rHMGB1) into embryonic rat ventricles to determine whether rHMGB1 can induce epileptogenic CD with pathophysiological characteristics similar to those of human CD. Compared with controls and 0.1 μg rHMGB1-treated rats, the cortical organization was severely disrupted in the 0.2 μg rHMGB1-treated rats, and microgyria and heterotopia also emerged; additionally, disoriented and deformed neurons were observed in the cortical lesions and heterotopias. Subcortical heterotopia appeared in the white matter and the gray–white junction of the 0.2 μg rHMGB1-treated rats. Moreover, there was decreased number of neurons in layer V–VI and an increased number of astrocytes in layer I and V of the cortical lesions. And the HMGB1 antagonist dexmedetomidine alleviated the changes induced by rHMGB1. Further, we found that TLR4 and NF-κB were increased after rHMGB1 administration. In addition, the excitatory receptors, N-methyl-D-aspartate receptor 1 (NR1), 2A (NR2A), and 2B (NR2B) immunoreactivity were increased, and immunoreactivity of excitatory amino acid transporter 1 (EAAT1) and 2 (EAAT2) were reduced in 0.2 μg rHMGB1-treated rats compared with controls. While there were no differences in the glutamic acid decarboxylase 65/67 (GAD65/67) immunoreactivity between the two groups. These results indicate that the excitation of cortical lesions was significantly increased. Furthermore, electroencephalogram (EEG) showed a shorter latency of seizure onset and a higher incidence of status epilepticus in the 0.2 μg rHMGB1-treated rats; the frequency and amplitude of EEG were higher in the treated rats than controls. Intriguingly, spontaneous electrographic seizure discharges were detected in the 0.2 μg rHMGB1-treated rats after 5 months of age, and spike-wave discharges of approximately 8 Hz were the most significantly increased synchronous propagated waves throughout the general brain cortex. Taken together, these findings indicate that rHMGB1 exposure during pregnancy could contribute to the development of epileptogenic CD, which mimicked some pathophysiological characteristics of human CD.
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Affiliation(s)
- Xiaolin Yang
- National Comprehensive Epilepsy Center, Department of Neurosurgery, Second Affiliated Hospital, Army Medical University, Chongqing, China
| | - Xiaoqing Zhang
- National Comprehensive Epilepsy Center, Department of Neurosurgery, Second Affiliated Hospital, Army Medical University, Chongqing, China
| | - Yuanshi Ma
- National Comprehensive Epilepsy Center, Department of Neurosurgery, Second Affiliated Hospital, Army Medical University, Chongqing, China.,Department of Neurosurgery, First People's Hospital, Zhaotong, China
| | - Zhongke Wang
- National Comprehensive Epilepsy Center, Department of Neurosurgery, Second Affiliated Hospital, Army Medical University, Chongqing, China
| | - Kaixuan Huang
- National Comprehensive Epilepsy Center, Department of Neurosurgery, Second Affiliated Hospital, Army Medical University, Chongqing, China
| | - Guolong Liu
- National Comprehensive Epilepsy Center, Department of Neurosurgery, Second Affiliated Hospital, Army Medical University, Chongqing, China
| | - Kaifeng Shen
- National Comprehensive Epilepsy Center, Department of Neurosurgery, Second Affiliated Hospital, Army Medical University, Chongqing, China
| | - Gang Zhu
- National Comprehensive Epilepsy Center, Department of Neurosurgery, Second Affiliated Hospital, Army Medical University, Chongqing, China
| | - Tingting Wang
- National Comprehensive Epilepsy Center, Department of Neurosurgery, Second Affiliated Hospital, Army Medical University, Chongqing, China
| | - Shengqing Lv
- National Comprehensive Epilepsy Center, Department of Neurosurgery, Second Affiliated Hospital, Army Medical University, Chongqing, China
| | - Chunqing Zhang
- National Comprehensive Epilepsy Center, Department of Neurosurgery, Second Affiliated Hospital, Army Medical University, Chongqing, China
| | - Hui Yang
- National Comprehensive Epilepsy Center, Department of Neurosurgery, Second Affiliated Hospital, Army Medical University, Chongqing, China
| | - Shiyong Liu
- National Comprehensive Epilepsy Center, Department of Neurosurgery, Second Affiliated Hospital, Army Medical University, Chongqing, China
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Marshall GF, Gonzalez-Sulser A, Abbott CM. Modelling epilepsy in the mouse: challenges and solutions. Dis Model Mech 2021; 14:dmm.047449. [PMID: 33619078 PMCID: PMC7938804 DOI: 10.1242/dmm.047449] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
In most mouse models of disease, the outward manifestation of a disorder can be measured easily, can be assessed with a trivial test such as hind limb clasping, or can even be observed simply by comparing the gross morphological characteristics of mutant and wild-type littermates. But what if we are trying to model a disorder with a phenotype that appears only sporadically and briefly, like epileptic seizures? The purpose of this Review is to highlight the challenges of modelling epilepsy, in which the most obvious manifestation of the disorder, seizures, occurs only intermittently, possibly very rarely and often at times when the mice are not under direct observation. Over time, researchers have developed a number of ways in which to overcome these challenges, each with their own advantages and disadvantages. In this Review, we describe the genetics of epilepsy and the ways in which genetically altered mouse models have been used. We also discuss the use of induced models in which seizures are brought about by artificial stimulation to the brain of wild-type animals, and conclude with the ways these different approaches could be used to develop a wider range of anti-seizure medications that could benefit larger patient populations. Summary: This Review discusses the challenges of modelling epilepsy in mice, a condition in which the outward manifestation of the disorder appears only sporadically, and reviews possible solutions encompassing both genetic and induced models.
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Affiliation(s)
- Grant F Marshall
- Centre for Genomic and Experimental Medicine, MRC Institute of Genetics and Molecular Medicine, University of Edinburgh, Western General Hospital, Crewe Road, Edinburgh EH4 2XU, UK.,Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh EH8 9XD, UK
| | - Alfredo Gonzalez-Sulser
- Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh EH8 9XD, UK.,Centre for Discovery Brain Sciences, 1 George Square, University of Edinburgh, Edinburgh EH8 9XD, UK
| | - Catherine M Abbott
- Centre for Genomic and Experimental Medicine, MRC Institute of Genetics and Molecular Medicine, University of Edinburgh, Western General Hospital, Crewe Road, Edinburgh EH4 2XU, UK .,Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh EH8 9XD, UK
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41
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Zimmer TS, Broekaart DWM, Gruber VE, van Vliet EA, Mühlebner A, Aronica E. Tuberous Sclerosis Complex as Disease Model for Investigating mTOR-Related Gliopathy During Epileptogenesis. Front Neurol 2020; 11:1028. [PMID: 33041976 PMCID: PMC7527496 DOI: 10.3389/fneur.2020.01028] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2020] [Accepted: 08/06/2020] [Indexed: 12/13/2022] Open
Abstract
Tuberous sclerosis complex (TSC) represents the prototypic monogenic disorder of the mammalian target of rapamycin (mTOR) pathway dysregulation. It provides the rational mechanistic basis of a direct link between gene mutation and brain pathology (structural and functional abnormalities) associated with a complex clinical phenotype including epilepsy, autism, and intellectual disability. So far, research conducted in TSC has been largely neuron-oriented. However, the neuropathological hallmarks of TSC and other malformations of cortical development also include major morphological and functional changes in glial cells involving astrocytes, oligodendrocytes, NG2 glia, and microglia. These cells and their interglial crosstalk may offer new insights into the common neurobiological mechanisms underlying epilepsy and the complex cognitive and behavioral comorbidities that are characteristic of the spectrum of mTOR-associated neurodevelopmental disorders. This review will focus on the role of glial dysfunction, the interaction between glia related to mTOR hyperactivity, and its contribution to epileptogenesis in TSC. Moreover, we will discuss how understanding glial abnormalities in TSC might give valuable insight into the pathophysiological mechanisms that could help to develop novel therapeutic approaches for TSC or other pathologies characterized by glial dysfunction and acquired mTOR hyperactivation.
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Affiliation(s)
- Till S Zimmer
- Department of (Neuro)Pathology, Amsterdam Neuroscience, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, Netherlands
| | - Diede W M Broekaart
- Department of (Neuro)Pathology, Amsterdam Neuroscience, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, Netherlands
| | | | - Erwin A van Vliet
- Department of (Neuro)Pathology, Amsterdam Neuroscience, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, Netherlands.,Swammerdam Institute for Life Sciences, Center for Neuroscience, University of Amsterdam, Amsterdam, Netherlands
| | - Angelika Mühlebner
- Department of (Neuro)Pathology, Amsterdam Neuroscience, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, Netherlands
| | - Eleonora Aronica
- Department of (Neuro)Pathology, Amsterdam Neuroscience, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, Netherlands.,Stichting Epilepsie Instellingen Nederland (SEIN), Heemstede, Netherlands
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42
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Iffland PH, Barnes AE, Baybis M, Crino PB. Dynamic analysis of 4E-BP1 phosphorylation in neurons with Tsc2 or Depdc5 knockout. Exp Neurol 2020; 334:113432. [PMID: 32781001 DOI: 10.1016/j.expneurol.2020.113432] [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: 03/06/2020] [Revised: 07/13/2020] [Accepted: 08/04/2020] [Indexed: 12/15/2022]
Abstract
TSC1 or TSC2 mutations cause Tuberous Sclerosis Complex (TSC), and lead to mechanistic target of rapamycin (mTOR) hyperactivation evidenced by hyperphosphorylation of ribosomal S6 protein and 4-elongation factor binding protein 1 (4E-BP1). Amino acid (AA) levels modulate mTOR-dependent S6 and 4E-BP1 phosphorylation in non-neural cells, but this has not been comprehensively investigated in neurons. The effects of AA levels on mTOR signaling and S6 and 4E-BP1 phosphorylation were analyzed in Tsc2 and Depdc5 (a distinct mTOR regulatory gene associated with epilepsy) CRISPR-edited Neuro2a (N2a) cells and differentiated neurons. Tsc2 or Depdc5 knockout (KO) led to S6 and 4E-BP1 hyperphosphorylation and cell soma enlargement, but while Tsc2 KO N2a cells exhibited reduced S6 phosphorylation (Ser240/244) and cell soma size after incubation in AA free (AAF) media, Depdc5 KO cells did not. Using a CFP/YFP FRET-biosensor coupled to 4E-BP1, we assayed 4E-BP1 phosphorylation in living N2a cells and differentiated neurons following Tsc2 or Depdc5 KO. AAF conditions reduced 4E-BP1 phosphorylation in Tsc2 KO N2a cells but had no effect in Depdc5 KO cells. Rapamycin blocked S6 protein phosphorylation but had no effect on 4E-BP1 phosphorylation, following either Tsc2 or Depdc5 KO. Confocal imaging demonstrated that AAF media promoted movement of mTOR off the lysosome, functionally inactivating mTOR, in Tsc2 KO but not Depdc5 KO cells, demonstrating that AA levels modulate lysosomal mTOR localization and account, in part, for differential effects of AAF conditions following Tsc2 versus Depdc5 KO. AA levels and rapamycin differentially modulate S6 and 4E-BP1 phosphorylation and mTOR lysosomal localization in neurons following Tsc2 KO versus Depdc5 KO. Neuronal mTOR signaling in mTOR-associated epilepsies may have distinct responses to mTOR inhibitors and to levels of cellular amino acids.
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Affiliation(s)
- Philip H Iffland
- Department of Neurology, University of Maryland School of Medicine, Baltimore, MD, United States of America
| | - Allan E Barnes
- Department of Neurology, University of Maryland School of Medicine, Baltimore, MD, United States of America
| | - Marianna Baybis
- Department of Neurology, University of Maryland School of Medicine, Baltimore, MD, United States of America
| | - Peter B Crino
- Department of Neurology, University of Maryland School of Medicine, Baltimore, MD, United States of America.
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43
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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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44
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Tabatabaei N, Hou S, Kim KW, Tahmasebi S. Signaling pathways that control mRNA translation initiation in macrophages. Cell Signal 2020; 73:109700. [PMID: 32593651 DOI: 10.1016/j.cellsig.2020.109700] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 06/11/2020] [Accepted: 06/23/2020] [Indexed: 12/14/2022]
Abstract
Translational control in mammalian cells plays a critical role in regulating differentiation, cell growth, cell cycle and response to diverse stresses. Macrophages are one of the most versatile cell types in the body. They are professional phagocytic cells that can be found in almost all tissues and adapt tissue-specific functions. Recent studies highlight the importance of translational control in macrophages during invasion of pathogens, exposure to cytokines and in the context of tissue specific functions. In this review, we summarize the current knowledge regarding the role of mRNA translational control in regulation of macrophages.
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Affiliation(s)
- Negar Tabatabaei
- Department of Pharmacology and Regenerative Medicine, University of Illinois College of Medicine, Chicago, IL, USA
| | - Shikun Hou
- Department of Pharmacology and Regenerative Medicine, University of Illinois College of Medicine, Chicago, IL, USA
| | - Ki-Wook Kim
- Department of Pharmacology and Regenerative Medicine, University of Illinois College of Medicine, Chicago, IL, USA.
| | - Soroush Tahmasebi
- Department of Pharmacology and Regenerative Medicine, University of Illinois College of Medicine, Chicago, IL, USA.
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45
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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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46
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Casillas‐Espinosa PM, Ali I, O'Brien TJ. Neurodegenerative pathways as targets for acquired epilepsy therapy development. Epilepsia Open 2020; 5:138-154. [PMID: 32524040 PMCID: PMC7278567 DOI: 10.1002/epi4.12386] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Revised: 02/13/2020] [Accepted: 02/24/2020] [Indexed: 12/16/2022] Open
Abstract
There is a growing body of clinical and experimental evidence that neurodegenerative diseases and epileptogenesis after an acquired brain insult may share common etiological mechanisms. Acquired epilepsy commonly develops as a comorbid condition in patients with neurodegenerative diseases such as Alzheimer's disease, although it is likely much under diagnosed in practice. Progressive neurodegeneration has also been described after traumatic brain injury, stroke, and other forms of brain insults. Moreover, recent evidence has shown that acquired epilepsy is often a progressive disorder that is associated with the development of drug resistance, cognitive decline, and worsening of other neuropsychiatric comorbidities. Therefore, new pharmacological therapies that target neurobiological pathways that underpin neurodegenerative diseases have potential to have both an anti-epileptogenic and disease-modifying effect on the seizures in patients with acquired epilepsy, and also mitigate the progressive neurocognitive and neuropsychiatric comorbidities. Here, we review the neurodegenerative pathways that are plausible targets for the development of novel therapies that could prevent the development or modify the progression of acquired epilepsy, and the supporting published experimental and clinical evidence.
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Affiliation(s)
- Pablo M. Casillas‐Espinosa
- Departments of Neuroscience and MedicineCentral Clinical SchoolMonash UniversityMelbourneVic.Australia
- Department of MedicineThe Royal Melbourne HospitalThe University of MelbourneMelbourneVic.Australia
| | - Idrish Ali
- Departments of Neuroscience and MedicineCentral Clinical SchoolMonash UniversityMelbourneVic.Australia
- Department of MedicineThe Royal Melbourne HospitalThe University of MelbourneMelbourneVic.Australia
| | - Terence J. O'Brien
- Departments of Neuroscience and MedicineCentral Clinical SchoolMonash UniversityMelbourneVic.Australia
- Department of MedicineThe Royal Melbourne HospitalThe University of MelbourneMelbourneVic.Australia
- Department of NeurologyThe Alfred HospitalMelbourneVic.Australia
- Department of NeurologyThe Royal Melbourne HospitalParkvilleVic.Australia
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47
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Auvin S, Avbersek A, Bast T, Chiron C, Guerrini R, Kaminski RM, Lagae L, Muglia P, Cross JH. Drug Development for Rare Paediatric Epilepsies: Current State and Future Directions. Drugs 2020; 79:1917-1935. [PMID: 31734883 DOI: 10.1007/s40265-019-01223-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Rare diseases provide a challenge in the evaluation of new therapies. However, orphan drug development is of increasing interest because of the legislation enabling facilitated support by regulatory agencies through scientific advice, and the protection of the molecules with orphan designation. In the landscape of the rare epilepsies, very few syndromes, namely Dravet syndrome, Lennox-Gastaut syndrome and West syndrome, have been subject to orphan drug development. Despite orphan designations for rare epilepsies having dramatically increased in the past 10 years, the number of approved drugs remains limited and restricted to a handful of epilepsy syndromes. In this paper, we describe the current state of orphan drug development for rare epilepsies. We identified a large number of compounds currently under investigation, but mostly in the same rare epilepsy syndromes as in the past. A rationale for further development in rare epilepsies could be based on the match between the drug mechanisms of action and the knowledge of the causative gene mutation or by evidence from animal models. In case of the absence of strong pathophysiological hypotheses, exploratory/basket clinical studies could be helpful to identify a subpopulation that may benefit from the new drug. We provide some suggestions for future improvements in orphan drug development such as promoting paediatric drug investigations, better evaluation of the incidence and the prevalence, together with the natural history data, and the development of new primary outcomes.
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Affiliation(s)
- Stéphane Auvin
- PROTECT, INSERM U1141, Université de Paris, Paris, France. .,Service de Neurologie Pédiatrique, AP-HP, Hôpital Universitaire Robert-Debré, 48, Boulevard Sérurier, 75935, Paris Cedex 19, France.
| | | | - Thomas Bast
- The Kork Epilepsy Center, Kehl-Kork, Germany.,Medical Faculty of the University of Freiburg, Freiburg, Germany
| | - Catherine Chiron
- PROTECT, INSERM U1141, Université de Paris, Paris, France.,Service de Neurologie Pédiatrique, AP-HP, Hôpital Necker-Enfanst Malades, Paris, France
| | - Renzo Guerrini
- Neuroscience Department, Children's Hospital Anna Meyer-University of Florence, Florence, Italy
| | - Rafal M Kaminski
- UCB Pharma, Braine-l'Alleud, Belgium.,Roche Pharma Research and Early Development (pRED), Roche Innovation Center, Basel, Switzerland
| | - Lieven Lagae
- Department Development and Regeneration, Section Paediatric Neurology, University Hospitals, University of Leuven, Leuven, Belgium
| | | | - J Helen Cross
- UCL NIHR BRC Great Ormond Street Institute of Child Health, London, UK
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48
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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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49
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Tai C, Chang CW, Yu GQ, Lopez I, Yu X, Wang X, Guo W, Mucke L. Tau Reduction Prevents Key Features of Autism in Mouse Models. Neuron 2020; 106:421-437.e11. [PMID: 32126198 DOI: 10.1016/j.neuron.2020.01.038] [Citation(s) in RCA: 54] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Revised: 11/21/2019] [Accepted: 01/27/2020] [Indexed: 01/06/2023]
Abstract
Autism is characterized by repetitive behaviors, impaired social interactions, and communication deficits. It is a prevalent neurodevelopmental disorder, and available treatments offer little benefit. Here, we show that genetically reducing the protein tau prevents behavioral signs of autism in two mouse models simulating distinct causes of this condition. Similar to a proportion of people with autism, both models have epilepsy, abnormally enlarged brains, and overactivation of the phosphatidylinositol 3-kinase (PI3K)/Akt (protein kinase B)/ mammalian target of rapamycin (mTOR) signaling pathway. All of these abnormalities were prevented or markedly diminished by partial or complete genetic removal of tau. We identify disinhibition of phosphatase and tensin homolog deleted on chromosome 10 (PTEN), a negative PI3K regulator that tau controls, as a plausible mechanism and demonstrate that tau interacts with PTEN via tau's proline-rich domain. Our findings suggest an enabling role of tau in the pathogenesis of autism and identify tau reduction as a potential therapeutic strategy for some of the disorders that cause this condition.
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Affiliation(s)
- Chao Tai
- Gladstone Institute of Neurological Disease, Gladstone Institutes, San Francisco, CA 94158, USA
| | - Che-Wei Chang
- Gladstone Institute of Neurological Disease, Gladstone Institutes, San Francisco, CA 94158, USA
| | - Gui-Qiu Yu
- Gladstone Institute of Neurological Disease, Gladstone Institutes, San Francisco, CA 94158, USA
| | - Isabel Lopez
- Gladstone Institute of Neurological Disease, Gladstone Institutes, San Francisco, CA 94158, USA
| | - Xinxing Yu
- Gladstone Institute of Neurological Disease, Gladstone Institutes, San Francisco, CA 94158, USA
| | - Xin Wang
- Gladstone Institute of Neurological Disease, Gladstone Institutes, San Francisco, CA 94158, USA
| | - Weikun Guo
- Gladstone Institute of Neurological Disease, Gladstone Institutes, San Francisco, CA 94158, USA
| | - Lennart Mucke
- Gladstone Institute of Neurological Disease, Gladstone Institutes, San Francisco, CA 94158, USA; Department of Neurology and Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA 94143, USA.
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50
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Abstract
Epilepsy is a long-term neurological disease characterized by convulsions that can be recurrent. It is mainly caused by an imbalance between excitation and inhibition in the central nervous system. Currently, the pathogenesis is still unclear, although it may be related to changes in ion channels, neurotransmitters and glial cells. In recent years, increasing attention has been paid to the role of autophagy in the development of epilepsy. This chapter focuses on the role of the mTOR pathway in epileptogenesis and the relationship between autophagy, glycogen metabolism and Lafora disease and discusses the potential role of autophagy as a target for the treatment of epilepsy.
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Affiliation(s)
- Meihong Lv
- Institute of Neuroscience, Soochow University, Suzhou, Jiangsu Province, China
| | - Quanhong Ma
- Institute of Neuroscience, Soochow University, Suzhou, Jiangsu Province, China.
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