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Saviuk M, Sleptsova E, Redkin T, Turubanova V. Unexplained Causes of Glioma-Associated Epilepsies: A Review of Theories and an Area for Research. Cancers (Basel) 2023; 15:5539. [PMID: 38067243 PMCID: PMC10705208 DOI: 10.3390/cancers15235539] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Revised: 11/17/2023] [Accepted: 11/20/2023] [Indexed: 12/25/2023] Open
Abstract
Approximately 30% of glioma patients are able to survive beyond one year postdiagnosis. And this short time is often overshadowed by glioma-associated epilepsy. This condition severely impairs the patient's quality of life and causes great suffering. The genetic, molecular and cellular mechanisms underlying tumour development and epileptogenesis remain incompletely understood, leading to numerous unanswered questions. The various types of gliomas, namely glioblastoma, astrocytoma and oligodendroglioma, demonstrate distinct seizure susceptibility and disease progression patterns. Patterns have been identified in the presence of IDH mutations and epilepsy, with tumour location in cortical regions, particularly the frontal lobe, showing a more frequent association with seizures. Altered expression of TP53, MGMT and VIM is frequently detected in tumour cells from individuals with epilepsy associated with glioma. However, understanding the pathogenesis of these modifications poses a challenge. Moreover, hypoxic effects induced by glioma and associated with the HIF-1a factor may have a significant impact on epileptogenesis, potentially resulting in epileptiform activity within neuronal networks. We additionally hypothesise about how the tumour may affect the functioning of neuronal ion channels and contribute to disruptions in the blood-brain barrier resulting in spontaneous depolarisations.
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Affiliation(s)
- Mariia Saviuk
- Institute of Neurosciences, National Research Lobachevsky State University of Nizhny Novgorod, 23 Gagarin Ave., 603022 Nizhny Novgorod, Russia; (M.S.); (E.S.); (T.R.)
- Cell Death Investigation and Therapy Laboratory, Anatomy and Embryology Unit, Department of Human Structure and Repair, Faculty of Medicine and Health Sciences, Ghent University, C. Heymanslaan 10, 9000 Ghent, Belgium
| | - Ekaterina Sleptsova
- Institute of Neurosciences, National Research Lobachevsky State University of Nizhny Novgorod, 23 Gagarin Ave., 603022 Nizhny Novgorod, Russia; (M.S.); (E.S.); (T.R.)
| | - Tikhon Redkin
- Institute of Neurosciences, National Research Lobachevsky State University of Nizhny Novgorod, 23 Gagarin Ave., 603022 Nizhny Novgorod, Russia; (M.S.); (E.S.); (T.R.)
| | - Victoria Turubanova
- Institute of Neurosciences, National Research Lobachevsky State University of Nizhny Novgorod, 23 Gagarin Ave., 603022 Nizhny Novgorod, Russia; (M.S.); (E.S.); (T.R.)
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Levitin MO, Rawlins LE, Sanchez-Andrade G, Arshad OA, Collins SC, Sawiak SJ, Iffland PH, Andersson MHL, Bupp C, Cambridge EL, Coomber EL, Ellis I, Herkert JC, Ironfield H, Jory L, Kretz PF, Kant SG, Neaverson A, Nibbeling E, Rowley C, Relton E, Sanderson M, Scott EM, Stewart H, Shuen AY, Schreiber J, Tuck L, Tonks J, Terkelsen T, van Ravenswaaij-Arts C, Vasudevan P, Wenger O, Wright M, Day A, Hunter A, Patel M, Lelliott CJ, Crino PB, Yalcin B, Crosby AH, Baple EL, Logan DW, Hurles ME, Gerety SS. Models of KPTN-related disorder implicate mTOR signalling in cognitive and overgrowth phenotypes. Brain 2023; 146:4766-4783. [PMID: 37437211 PMCID: PMC10629792 DOI: 10.1093/brain/awad231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Revised: 05/31/2023] [Accepted: 06/18/2023] [Indexed: 07/14/2023] Open
Abstract
KPTN-related disorder is an autosomal recessive disorder associated with germline variants in KPTN (previously known as kaptin), a component of the mTOR regulatory complex KICSTOR. To gain further insights into the pathogenesis of KPTN-related disorder, we analysed mouse knockout and human stem cell KPTN loss-of-function models. Kptn -/- mice display many of the key KPTN-related disorder phenotypes, including brain overgrowth, behavioural abnormalities, and cognitive deficits. By assessment of affected individuals, we have identified widespread cognitive deficits (n = 6) and postnatal onset of brain overgrowth (n = 19). By analysing head size data from their parents (n = 24), we have identified a previously unrecognized KPTN dosage-sensitivity, resulting in increased head circumference in heterozygous carriers of pathogenic KPTN variants. Molecular and structural analysis of Kptn-/- mice revealed pathological changes, including differences in brain size, shape and cell numbers primarily due to abnormal postnatal brain development. Both the mouse and differentiated induced pluripotent stem cell models of the disorder display transcriptional and biochemical evidence for altered mTOR pathway signalling, supporting the role of KPTN in regulating mTORC1. By treatment in our KPTN mouse model, we found that the increased mTOR signalling downstream of KPTN is rapamycin sensitive, highlighting possible therapeutic avenues with currently available mTOR inhibitors. These findings place KPTN-related disorder in the broader group of mTORC1-related disorders affecting brain structure, cognitive function and network integrity.
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Affiliation(s)
- Maria O Levitin
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge CB10 1SA, UK
- Evox Therapeutics Limited, Oxford OX4 4HG, UK
| | - Lettie E Rawlins
- RILD Wellcome Wolfson Medical Research Centre, University of Exeter, Exeter EX2 5DW, UK
- Peninsula Clinical Genetics Service, Royal Devon University Healthcare NHS Foundation Trust, Exeter EX1 2ED, UK
| | | | - Osama A Arshad
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge CB10 1SA, UK
| | - Stephan C Collins
- INSERM Unit 1231, Université de Bourgogne Franche-Comté, Dijon 21078, France
| | - Stephen J Sawiak
- Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge CB2 3EB, UK
- Wolfson Brain Imaging Centre, Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2 0QQ, UK
| | - Phillip H Iffland
- Department of Neurology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Malin H L Andersson
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge CB10 1SA, UK
| | - Caleb Bupp
- Spectrum Health, Helen DeVos Children’s Hospital, Grand Rapids, MI 49503, USA
| | - Emma L Cambridge
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge CB10 1SA, UK
| | - Eve L Coomber
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge CB10 1SA, UK
| | - Ian Ellis
- Department of Clinical Genetics, Alder Hey Children’s Hospital, Liverpool L14 5AB, UK
| | - Johanna C Herkert
- Department of Genetics, University Medical Centre, University of Groningen, Groningen 9713 GZ, The Netherlands
| | - Holly Ironfield
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge CB10 1SA, UK
| | - Logan Jory
- Haven Clinical Psychology Practice Ltd, Bude, Cornwall EX23 9HP, UK
| | | | - Sarina G Kant
- Department of Clinical Genetics, Erasmus MC, University Medical Center Rotterdam, Rotterdam 3015 GD, The Netherlands
- Department of Clinical Genetics, Leiden University Medical Center, Leiden 2300 RC, The Netherlands
| | - Alexandra Neaverson
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge CB10 1SA, UK
- Open Targets, Wellcome Genome Campus, Hinxton, Cambridge CB10 1SA, UK
- Department of Genetics, University of Cambridge, Cambridge CB2 3EH, UK
| | - Esther Nibbeling
- Laboratory for Diagnostic Genome Analysis, Department of Clinical Genetics, Leiden University Medical Center, Leiden 3015 GD, The Netherlands
| | - Christine Rowley
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge CB10 1SA, UK
- Institute of Metabolic Science, Cambridge University, Cambridge CB2 0QQ, UK
| | - Emily Relton
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge CB10 1SA, UK
- Faculty of Health and Medical Science, University of Surrey, Guildford GU2 7YH, UK
| | - Mark Sanderson
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge CB10 1SA, UK
| | - Ethan M Scott
- New Leaf Center, Clinic for Special Children, Mount Eaton, OH 44659, USA
| | - Helen Stewart
- Oxford Centre for Genomic Medicine, Oxford University Hospitals NHS Trust, Oxford OX3 7HE, UK
| | - Andrew Y Shuen
- London Health Sciences Centre, London, ON N6A 5W9, Canada
- Division of Medical Genetics, Department of Pediatrics, Schulich School of Medicine and Dentistry, Western University, London, ON N6A 5W9, Canada
| | - John Schreiber
- Department of Neurology, Children’s National Medical Center, Washington DC 20007, USA
| | - Liz Tuck
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge CB10 1SA, UK
| | - James Tonks
- Haven Clinical Psychology Practice Ltd, Bude, Cornwall EX23 9HP, UK
| | - Thorkild Terkelsen
- Department of Clinical Genetics, Aarhus University Hospital, Aarhus DK-8200, Denmark
| | - Conny van Ravenswaaij-Arts
- Department of Genetics, University Medical Centre, University of Groningen, Groningen 9713 GZ, The Netherlands
| | - Pradeep Vasudevan
- Department of Clinical Genetics, University Hospitals of Leicester, Leicester Royal Infirmary, Leicester LE1 7RH, UK
| | - Olivia Wenger
- New Leaf Center, Clinic for Special Children, Mount Eaton, OH 44659, USA
| | - Michael Wright
- Institute of Human Genetics, International Centre for Life, Newcastle upon Tyne NE1 7RU, UK
| | - Andrew Day
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge CB10 1SA, UK
- Qkine Ltd., Cambridge CB5 8HW, UK
| | - Adam Hunter
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge CB10 1SA, UK
| | - Minal Patel
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge CB10 1SA, UK
| | - Christopher J Lelliott
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge CB10 1SA, UK
- Institute of Metabolic Science, Cambridge University, Cambridge CB2 0QQ, UK
| | - Peter B Crino
- Department of Neurology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Binnaz Yalcin
- INSERM Unit 1231, Université de Bourgogne Franche-Comté, Dijon 21078, France
| | - Andrew H Crosby
- RILD Wellcome Wolfson Medical Research Centre, University of Exeter, Exeter EX2 5DW, UK
| | - Emma L Baple
- RILD Wellcome Wolfson Medical Research Centre, University of Exeter, Exeter EX2 5DW, UK
- Peninsula Clinical Genetics Service, Royal Devon University Healthcare NHS Foundation Trust, Exeter EX1 2ED, UK
| | - Darren W Logan
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge CB10 1SA, UK
- Waltham Petcare Science Institute, Waltham on the Wolds LE14 4RT, UK
| | - Matthew E Hurles
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge CB10 1SA, UK
- Open Targets, Wellcome Genome Campus, Hinxton, Cambridge CB10 1SA, UK
| | - Sebastian S Gerety
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge CB10 1SA, UK
- Open Targets, Wellcome Genome Campus, Hinxton, Cambridge CB10 1SA, UK
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Ancora C, Marchi M, Bonardi CM, Sartori G, Lopreiato R, Zuccarello D, D'Errico I, Nosadini M, Sartori S, Boniver C, Toldo I, Salviati L. Electroclinical Features in Two Novel STRADA Patients and a Functional Yeast Assay for the Validation of Missense STRADA Mutations. Pediatr Neurol 2023; 148:152-156. [PMID: 37722301 DOI: 10.1016/j.pediatrneurol.2023.08.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Revised: 08/11/2023] [Accepted: 08/14/2023] [Indexed: 09/20/2023]
Abstract
Loss of function of the STRADA gene, an upstream mTOR inhibitor, causes a rare neurodevelopmental disorder characterized by polyhydramnios, megalencephaly, and symptomatic epilepsy (PMSE syndrome). Patients display a homogeneous phenotype including early-onset drug-resistant epilepsy, severe psychomotor delay, multisystemic comorbidities, and increased risk of premature death. The administration of sirolimus, an mTOR inhibitor, is helpful in controlling seizures in this syndrome. We report the electroclinical phenotype of two novel patients and the development of a yeast model to validate the pathogenicity of missense variants. Patient 1 harbored a missense STRADA variant and had a peculiar electroclinical phenotype with a relatively mild epilepsy course. Patient 2 harbored a truncating STRADA variant and showed a typical PMSE phenotype and a favorable response to early treatment with sirolimus. When we modeled the p.(Ser264Arg) STRADA change in its yeast homolog SPS1, it impaired SPS1 function. The results underlie the importance of a timely molecular diagnosis in these patients and show that yeast is a simple yet effective model to validate the pathogenicity of missense variants.
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Affiliation(s)
- Caterina Ancora
- Pediatric Neurology and Neurophysiology Unit, Department of Women's and Children's Health, University of Padua, Padua, Italy
| | - Marco Marchi
- Clinical Genetics Unit, Department of Women's and Children's Health, University of Padua, Padua, Italy; Clinical Genetics Lab, Città della Speranza Pediatric Research Institute, Padua, Italy
| | - Claudia Maria Bonardi
- Pediatric Neurology and Neurophysiology Unit, Department of Women's and Children's Health, University of Padua, Padua, Italy
| | - Geppo Sartori
- Department of Biomedical Sciences, University of Padua, Padua, Italy
| | | | - Daniela Zuccarello
- Clinical Genetics Unit, Department of Women's and Children's Health, University of Padua, Padua, Italy
| | | | - Margherita Nosadini
- Pediatric Neurology and Neurophysiology Unit, Department of Women's and Children's Health, University of Padua, Padua, Italy
| | - Stefano Sartori
- Pediatric Neurology and Neurophysiology Unit, Department of Women's and Children's Health, University of Padua, Padua, Italy
| | - Clementina Boniver
- Pediatric Neurology and Neurophysiology Unit, Department of Women's and Children's Health, University of Padua, Padua, Italy
| | - Irene Toldo
- Pediatric Neurology and Neurophysiology Unit, Department of Women's and Children's Health, University of Padua, Padua, Italy.
| | - Leonardo Salviati
- Clinical Genetics Unit, Department of Women's and Children's Health, University of Padua, Padua, Italy; Clinical Genetics Lab, Città della Speranza Pediatric Research Institute, Padua, Italy
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Dhamne SC, Modi ME, Gray A, Bonazzi S, Craig L, Bainbridge E, Lalani L, Super CE, Schaeffer S, Capre K, Lubicka D, Liang G, Burdette D, McTighe SM, Gurnani S, Vermudez SAD, Curtis D, Wilson CJ, Hameed MQ, D'Amore A, Rotenberg A, Sahin M. Seizure reduction in TSC2-mutant mouse model by an mTOR catalytic inhibitor. Ann Clin Transl Neurol 2023; 10:1790-1801. [PMID: 37545094 PMCID: PMC10578885 DOI: 10.1002/acn3.51868] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Revised: 07/14/2023] [Accepted: 07/23/2023] [Indexed: 08/08/2023] Open
Abstract
OBJECTIVE Tuberous sclerosis complex (TSC) is a neurodevelopmental disorder caused by autosomal-dominant pathogenic variants in either the TSC1 or TSC2 gene, and it is characterized by hamartomas in multiple organs, such as skin, kidney, lung, and brain. These changes can result in epilepsy, learning disabilities, and behavioral complications, among others. The mechanistic link between TSC and the mechanistic target of the rapamycin (mTOR) pathway is well established, thus mTOR inhibitors can potentially be used to treat the clinical manifestations of the disorder, including epilepsy. METHODS In this study, we tested the efficacy of a novel mTOR catalytic inhibitor (here named Tool Compound 1 or TC1) previously reported to be more brain-penetrant compared with other mTOR inhibitors. Using a well-characterized hypomorphic Tsc2 mouse model, which displays a translationally relevant seizure phenotype, we tested the efficacy of TC1. RESULTS Our results show that chronic treatment with this novel mTOR catalytic inhibitor (TC1), which affects both the mTORC1 and mTORC2 signaling complexes, reduces seizure burden, and extends the survival of Tsc2 hypomorphic mice, restoring species typical weight gain over development. INTERPRETATION Novel mTOR catalytic inhibitor TC1 exhibits a promising therapeutic option in the treatment of TSC.
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Affiliation(s)
- Sameer C. Dhamne
- F.M. Kirby Neurobiology Center, Rosamund Stone Zander Translational Neuroscience Center, Department of Neurology, Boston Children's Hospital, Harvard Medical SchoolBostonMassachusettsUSA
| | - Meera E. Modi
- F.M. Kirby Neurobiology Center, Rosamund Stone Zander Translational Neuroscience Center, Department of Neurology, Boston Children's Hospital, Harvard Medical SchoolBostonMassachusettsUSA
| | - Audrey Gray
- Novartis Institutes for Biomedical ResearchCambridgeMassachusettsUSA
| | - Simone Bonazzi
- Novartis Institutes for Biomedical ResearchCambridgeMassachusettsUSA
| | - Lucas Craig
- Novartis Institutes for Biomedical ResearchCambridgeMassachusettsUSA
| | - Elizabeth Bainbridge
- F.M. Kirby Neurobiology Center, Rosamund Stone Zander Translational Neuroscience Center, Department of Neurology, Boston Children's Hospital, Harvard Medical SchoolBostonMassachusettsUSA
| | - Lahin Lalani
- F.M. Kirby Neurobiology Center, Rosamund Stone Zander Translational Neuroscience Center, Department of Neurology, Boston Children's Hospital, Harvard Medical SchoolBostonMassachusettsUSA
| | - Chloe E. Super
- F.M. Kirby Neurobiology Center, Rosamund Stone Zander Translational Neuroscience Center, Department of Neurology, Boston Children's Hospital, Harvard Medical SchoolBostonMassachusettsUSA
| | - Samantha Schaeffer
- F.M. Kirby Neurobiology Center, Rosamund Stone Zander Translational Neuroscience Center, Department of Neurology, Boston Children's Hospital, Harvard Medical SchoolBostonMassachusettsUSA
| | - Ketthsy Capre
- Novartis Institutes for Biomedical ResearchCambridgeMassachusettsUSA
| | - Danuta Lubicka
- Novartis Institutes for Biomedical ResearchCambridgeMassachusettsUSA
| | - Guiqing Liang
- Novartis Institutes for Biomedical ResearchCambridgeMassachusettsUSA
| | - Doug Burdette
- Novartis Institutes for Biomedical ResearchCambridgeMassachusettsUSA
| | | | - Sarika Gurnani
- F.M. Kirby Neurobiology Center, Rosamund Stone Zander Translational Neuroscience Center, Department of Neurology, Boston Children's Hospital, Harvard Medical SchoolBostonMassachusettsUSA
| | - Sheryl Anne D. Vermudez
- F.M. Kirby Neurobiology Center, Rosamund Stone Zander Translational Neuroscience Center, Department of Neurology, Boston Children's Hospital, Harvard Medical SchoolBostonMassachusettsUSA
| | - Daniel Curtis
- Novartis Institutes for Biomedical ResearchCambridgeMassachusettsUSA
| | | | - Mustafa Q. Hameed
- F.M. Kirby Neurobiology Center, Rosamund Stone Zander Translational Neuroscience Center, Department of Neurology, Boston Children's Hospital, Harvard Medical SchoolBostonMassachusettsUSA
| | - Angelica D'Amore
- F.M. Kirby Neurobiology Center, Rosamund Stone Zander Translational Neuroscience Center, Department of Neurology, Boston Children's Hospital, Harvard Medical SchoolBostonMassachusettsUSA
| | - Alexander Rotenberg
- F.M. Kirby Neurobiology Center, Rosamund Stone Zander Translational Neuroscience Center, Department of Neurology, Boston Children's Hospital, Harvard Medical SchoolBostonMassachusettsUSA
| | - Mustafa Sahin
- F.M. Kirby Neurobiology Center, Rosamund Stone Zander Translational Neuroscience Center, Department of Neurology, Boston Children's Hospital, Harvard Medical SchoolBostonMassachusettsUSA
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Pucha KA, Ma TC, York W, Kang UJ, Kaufmann H, Kapogiannis D, Palma JA. Neuron-derived extracellular vesicles to examine brain mTOR target engagement with sirolimus in patients with multiple system atrophy. Parkinsonism Relat Disord 2023; 115:105821. [PMID: 37643509 PMCID: PMC10592064 DOI: 10.1016/j.parkreldis.2023.105821] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Revised: 08/19/2023] [Accepted: 08/23/2023] [Indexed: 08/31/2023]
Abstract
INTRODUCTION Impaired autophagy is a pathogenic mechanism in the synucleinopathies. Sirolimus, a potent mTOR inhibitor and autophagy activator, had no beneficial effects in a randomized placebo-controlled trial in patients with multiple system atrophy (MSA). Whether sirolimus effectively inhibited brain mTOR activity was unknown. We aimed to evaluate if patients with MSA treated with sirolimus had evidence of inhibited brain mTOR pathways by measuring neuron-derived serum extracellular vesicles (NEVs). METHODS Serum samples were collected from participants of the sirolimus-MSA trial, which randomized patients to sirolimus (2-6 mg/day) or placebo for 48 weeks. NEVs were immunoprecipitated with three antibodies-against neurons. Brain mTOR engagement was quantified as the change in the NEV phosphorylated mTOR (p-mTOR) to total-mTOR (tot-mTOR) ratio after 48 weeks of sirolimus. RESULTS Samples from 27 patients [mean (±SD) age, 59.2±7 years, 15 (55.5%) men] were analyzed (19 sirolimus, 8 placebo). Treated- and placebo-patients had similar p-mTOR:tot-mTOR ratio at 24 (placebo: 0.248 ± 0.03, sirolimus: 0.289 ± 0.02; P = 0.305) and 48 weeks (placebo: 0.299 ± 0.05, sirolimus: 0.261 ± 0.03; P = 0.544). The tot-mTOR, p-mTOR, or their ratio levels were not associated with Unified MSA Rating Scale (UMSARS) worsening. DISCUSSION These results are consistent with no brain mTOR engagement by oral sirolimus up to 6 mg/day. NEV-based biomarkers are a rational approach to investigating target engagement in clinical trials of brain-targeted therapeutics.
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Affiliation(s)
- Krishna A Pucha
- Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, MD, USA
| | - Thong C Ma
- Department of Neurology, New York University School of Medicine, New York, NY, USA
| | - William York
- Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, MD, USA
| | - Un Jung Kang
- Department of Neurology, New York University School of Medicine, New York, NY, USA
| | - Horacio Kaufmann
- Department of Neurology, New York University School of Medicine, New York, NY, USA
| | - Dimitrios Kapogiannis
- Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, MD, USA.
| | - Jose-Alberto Palma
- Department of Neurology, New York University School of Medicine, New York, NY, USA.
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Hadzsiev K, Hegyi M, Fogarasi A, Bodó-Baltavári T, Zsigmond A, Maász A, Szabó A, Till Á. Observation of a Possible Successful Treatment of DEPDC5-Related Epilepsy with mTOR Inhibitor. Neuropediatrics 2023; 54:344-346. [PMID: 37263295 PMCID: PMC10506865 DOI: 10.1055/a-2104-1614] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Accepted: 04/18/2023] [Indexed: 06/03/2023]
Abstract
The mechanistic target of the rapamycin signaling pathway serves as a central regulator of cell metabolism, growth, proliferation, and survival. In its regulation, the GTPase-activating protein activity toward Rags1 complex has an inhibitory effect. Mutations in genes encoding this complex protein are among the most common abnormalities in focal epilepsies. Within these mutations, the mutations affecting the DEPDC5 gene have been associated with different autosomal dominantly inherited epilepsy types. Due to the limited data available on mTOR inhibitor therapy in nontuberous sclerosis complex epileptic patients, here we present the clinical management of a patient with intractable epilepsy, skin hypopigmentation, and a DEPDC5 variant. The patient's phenotype is compatible with a nonlesional DEPDC5-related epileptic encephalopathy. We initiated compassionate, off-label everolimus treatment as the patient's condition continuously deteriorated. Due to bilateral pneumonia occurring at the beginning of the treatment, it was temporarily discontinued, and resumed in half the dose. Follow-up examination after 18 months showed a 90% reduction in seizure frequency with moderate improvement in attention function and nutritional status. Our case report emphasizes the importance of early genetic testing in patients with epileptic encephalopathy. Clinical consequences of mammalian target of rapamycin complex 1 (mTORC1) upregulation may be amenable to tailored treatment with mTOR inhibitors. A clinical trial on an international scale would be needed to draw conclusions.
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Affiliation(s)
- Kinga Hadzsiev
- Department of Medical Genetics, Medical School, Clinical Center, University of Pécs, Pécs, Hungary
| | - Márta Hegyi
- Bethesda Children's Hospital, Epilepsy Center, Budapest, Hungary
| | - András Fogarasi
- Bethesda Children's Hospital, Epilepsy Center, Budapest, Hungary
| | | | - Anna Zsigmond
- Department of Medical Genetics, Medical School, Clinical Center, University of Pécs, Pécs, Hungary
| | - Anita Maász
- Department of Medical Genetics, Medical School, Clinical Center, University of Pécs, Pécs, Hungary
| | - András Szabó
- Department of Medical Genetics, Medical School, Clinical Center, University of Pécs, Pécs, Hungary
| | - Ágnes Till
- Department of Medical Genetics, Medical School, Clinical Center, University of Pécs, Pécs, Hungary
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Zhao W, Xie C, Zhang X, Liu J, Liu J, Xia Z. Advances in the mTOR signaling pathway and its inhibitor rapamycin in epilepsy. Brain Behav 2023; 13:e2995. [PMID: 37221133 PMCID: PMC10275542 DOI: 10.1002/brb3.2995] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 03/15/2023] [Accepted: 03/22/2023] [Indexed: 05/25/2023] Open
Abstract
INTRODUCTION Epilepsy is one of the most common and serious brain syndromes and has adverse consequences on a patient's neurobiological, cognitive, psychological, and social wellbeing, thereby threatening their quality of life. Some patients with epilepsy experience poor treatment effects due to the unclear pathophysiological mechanisms of the syndrome. Dysregulation of the mammalian target of the rapamycin (mTOR) pathway is thought to play an important role in the onset and progression of some epilepsies. METHODS This review summarizes the role of the mTOR signaling pathway in the pathogenesis of epilepsy and the prospects for the use of mTOR inhibitors. RESULTS The mTOR pathway functions as a vital mediator in epilepsy development through diverse mechanisms, indicating that the it has great potential as an effective target for epilepsy therapy. The excessive activation of mTOR signaling pathway leads to structural changes in neurons, inhibits autophagy, exacerbates neuron damage, affects mossy fiber sprouting, enhances neuronal excitability, increases neuroinflammation, and is closely associated with tau upregulation in epilepsy. A growing number of studies have demonstrated that mTOR inhibitors exhibit significant antiepileptic effects in both clinical applications and animal models. Specifically, rapamycin, a specific inhibitor of TOR, reduces the intensity and frequency of seizures. Clinical studies in patients with tuberous sclerosis complex have shown that rapamycin has the function of reducing seizures and improving this disease. Everolimus, a chemically modified derivative of rapamycin, has been approved as an added treatment to other antiepileptic medicines. Further explorations are needed to evaluate the therapeutic efficacy and application value of mTOR inhibitors in epilepsy. CONCLUSIONS Targeting the mTOR signaling pathway provides a promising prospect for the treatment of epilepsy.
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Affiliation(s)
- Wei Zhao
- Department of GerontologyThe First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan HospitalJinanChina
| | - Cong Xie
- Department of GerontologyThe First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan HospitalJinanChina
| | - Xu Zhang
- Department of GerontologyThe First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan HospitalJinanChina
| | - Ju Liu
- Laboratory of Microvascular MedicineMedical Research CenterShandong Provincial Qianfoshan Hospital, Shandong UniversityJinanChina
| | - Jinzhi Liu
- Department of GerontologyThe First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan HospitalJinanChina
- Department of NeurologyLiaocheng People's Hospital and Liaocheng Clinical School of Shandong First Medical UniversityLiaochengChina
- Department of GerontologyCheeloo College of MedicineShandong Provincial Qianfoshan Hospital, Shandong UniversityJinanChina
- Department of Geriatric NeurologyThe First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan HospitalJinanChina
| | - Zhangyong Xia
- Department of NeurologyLiaocheng People's Hospital and Liaocheng Clinical School of Shandong First Medical UniversityLiaochengChina
- Department of NeurologyCheeloo College of MedicineLiaocheng People's Hospital, Shandong UniversityJinanChina
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8
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Hamed R, Eyal AD, Berman E, Eyal S. In silico screening for clinical efficacy of antiseizure medications: Not all central nervous system drugs are alike. Epilepsia 2023; 64:311-319. [PMID: 36478573 PMCID: PMC10107105 DOI: 10.1111/epi.17479] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Revised: 12/04/2022] [Accepted: 12/06/2022] [Indexed: 12/13/2022]
Affiliation(s)
- Roaa Hamed
- Institute for Drug Research, School of Pharmacy, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Amit David Eyal
- Computational Medicine Program, School of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Erez Berman
- Institute for Drug Research, School of Pharmacy, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Sara Eyal
- Institute for Drug Research, School of Pharmacy, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel
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9
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Lui A, Vanleuven J, Perekopskiy D, Liu D, Xu D, Alzayat O, Elgokhy T, Do T, Gann M, Martin R, Liu DZ. FDA-Approved Kinase Inhibitors in Preclinical and Clinical Trials for Neurological Disorders. Pharmaceuticals (Basel) 2022; 15. [PMID: 36558997 DOI: 10.3390/ph15121546] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Revised: 12/09/2022] [Accepted: 12/09/2022] [Indexed: 12/14/2022] Open
Abstract
Cancers and neurological disorders are two major types of diseases. We previously developed a new concept termed "Aberrant Cell Cycle Diseases" (ACCD), revealing that these two diseases share a common mechanism of aberrant cell cycle re-entry. The aberrant cell cycle re-entry is manifested as kinase/oncogene activation and tumor suppressor inactivation, which are hallmarks of both tumor growth in cancers and neuronal death in neurological disorders. Therefore, some cancer therapies (e.g., kinase inhibition, tumor suppressor elevation) can be leveraged for neurological treatments. The United States Food and Drug Administration (US FDA) has so far approved 74 kinase inhibitors, with numerous other kinase inhibitors in clinical trials, mostly for the treatment of cancers. In contrast, there are dire unmet needs of FDA-approved drugs for neurological treatments, such as Alzheimer's disease (AD), intracerebral hemorrhage (ICH), ischemic stroke (IS), traumatic brain injury (TBI), and others. In this review, we list these 74 FDA-approved kinase-targeted drugs and identify those that have been reported in preclinical and/or clinical trials for neurological disorders, with a purpose of discussing the feasibility and applicability of leveraging these cancer drugs (FDA-approved kinase inhibitors) for neurological treatments.
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10
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Iffland PH, Everett ME, Cobb-Pitstick KM, Bowser LE, Barnes AE, Babus JK, Romanowski AJ, Baybis M, Elziny S, Puffenberger EG, Gonzaga-Jauregui C, Poulopoulos A, Carson VJ, Crino PB. NPRL3 loss alters neuronal morphology, mTOR localization, cortical lamination and seizure threshold. Brain 2022; 145:3872-3885. [PMID: 35136953 PMCID: PMC10200289 DOI: 10.1093/brain/awac044] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 11/10/2021] [Accepted: 12/10/2021] [Indexed: 08/13/2023] Open
Abstract
Mutations in nitrogen permease regulator-like 3 (NPRL3), a component of the GATOR1 complex within the mTOR pathway, are associated with epilepsy and malformations of cortical development. Little is known about the effects of NPRL3 loss on neuronal mTOR signalling and morphology, or cerebral cortical development and seizure susceptibility. We report the clinical phenotypic spectrum of a founder NPRL3 pedigree (c.349delG, p.Glu117LysFS; n = 133) among Old Order Mennonites dating to 1727. Next, as a strategy to define the role of NPRL3 in cortical development, CRISPR/Cas9 Nprl3 knockout in Neuro2a cells in vitro and in foetal mouse brain in vivo was used to assess the effects of Nprl3 knockout on mTOR activation, subcellular mTOR localization, nutrient signalling, cell morphology and aggregation, cerebral cortical cytoarchitecture and network integrity. The NPRL3 pedigree exhibited an epilepsy penetrance of 28% and heterogeneous clinical phenotypes with a range of epilepsy semiologies, i.e. focal or generalized onset, brain imaging abnormalities, i.e. polymicrogyria, focal cortical dysplasia or normal imaging, and EEG findings, e.g. focal, multi-focal or generalized spikes, focal or generalized slowing. Whole exome analysis comparing a seizure-free group (n = 37) to those with epilepsy (n = 24) to search for gene modifiers for epilepsy did not identify a unique genetic modifier that explained the variability in seizure penetrance in this cohort. Nprl3 knockout in vitro caused mTOR pathway hyperactivation, cell soma enlargement and the formation of cellular aggregates seen in time-lapse videos that were prevented with the mTOR inhibitors rapamycin or torin1. In Nprl3 knockout cells, mTOR remained localized on the lysosome in a constitutively active conformation, as evidenced by phosphorylation of ribosomal S6 and 4E-BP1 proteins, even under nutrient starvation (amino acid-free) conditions, demonstrating that Nprl3 loss decouples mTOR activation from neuronal metabolic state. To model human malformations of cortical development associated with NPRL3 variants, we created a focal Nprl3 knockout in foetal mouse cortex by in utero electroporation and found altered cortical lamination and white matter heterotopic neurons, effects which were prevented with rapamycin treatment. EEG recordings showed network hyperexcitability and reduced seizure threshold to pentylenetetrazol treatment. NPRL3 variants are linked to a highly variable clinical phenotype which we propose results from mTOR-dependent effects on cell structure, cortical development and network organization.
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Affiliation(s)
- Philip H Iffland
- University of Maryland School of Medicine Departments of Neurology and Pharmacology, Baltimore, MD 21201, USA
| | | | | | | | - Allan E Barnes
- University of Maryland School of Medicine Departments of Neurology and Pharmacology, Baltimore, MD 21201, USA
| | - Janice K Babus
- University of Maryland School of Medicine Departments of Neurology and Pharmacology, Baltimore, MD 21201, USA
| | - Andrea J Romanowski
- University of Maryland School of Medicine Departments of Neurology and Pharmacology, Baltimore, MD 21201, USA
| | - Marianna Baybis
- University of Maryland School of Medicine Departments of Neurology and Pharmacology, Baltimore, MD 21201, USA
| | - Soad Elziny
- University of Maryland School of Medicine Departments of Neurology and Pharmacology, Baltimore, MD 21201, USA
| | | | | | - Alexandros Poulopoulos
- University of Maryland School of Medicine Departments of Neurology and Pharmacology, Baltimore, MD 21201, USA
| | | | - Peter B Crino
- University of Maryland School of Medicine Departments of Neurology and Pharmacology, Baltimore, MD 21201, USA
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11
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Hutson J, Siu VM, Rupar CA. Raisonnement clinique : L’hydramnios comme marqueur d’un syndrome génétique fœtal dans la population des mennonites du Vieil Ordre au Canada. Journal of Obstetrics and Gynaecology Canada 2022; 44:803-807. [DOI: 10.1016/j.jogc.2022.05.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Accepted: 01/19/2022] [Indexed: 11/29/2022]
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12
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Sharma S, Rana AK, Sharma A, Singh D. Inhibition of Mammalian Target of Rapamycin Attenuates Recurrent Seizures Associated Cardiac Damage in a Zebrafish Kindling Model of Chronic Epilepsy. J Neuroimmune Pharmacol 2022; 17:334-349. [PMID: 34537895 DOI: 10.1007/s11481-021-10021-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Accepted: 09/02/2021] [Indexed: 12/29/2022]
Abstract
Sudden Unexpected Death in Epilepsy (SUDEP) is primarily linked with the cardiac irregularities that occur due to recurrent seizures. Our previous studies found a role of mTOR pathway activation in seizures-linked cardiac damage in a rat model. In continuation to the earlier work, the present study was devised to explore the role of rapamycin (mTOR inhibitor and clinically used immunosuppressive agent) in a zebrafish kindling model and associated cardiac damage. Adult zebrafish were incubated with increasing concentrations of rapamycin (1, 2 and, 4 μM), followed by pentylenetetrazole (PTZ) exposure to record seizure latency and severity. In another experiment, zebrafish were subjected to a standardized PTZ kindling protocol. The kindled fish were treated daily with rapamycin for up to 25 days, along with PTZ to record seizure severity. At the end, zebrafish heart was excised for carbonylation assay, gene expression, and protein quantification studies. In the acute PTZ convulsion test, treatment with rapamycin showed a significant increase in seizure latency and decreased seizure severity without any change in seizure incidence. Treatment with rapamycin also reduced the severity of seizures in kindled fish. The cardiac expressions of gpx, nppb, kcnh2, scn5a, mapk8, stat3, rps6 and ddit were decreased, whereas the levels of trxr2 and beclin 1 were increased following rapamycin treatment in kindled fish. Furthermore, rapamycin treatment also decreased p-mTOR expression and protein carbonyls level in the fish cardiac tissue. The present study concluded that rapamycin reduces seizures and associated cardiac damage by inhibiting mTOR activation in the zebrafish kindling model.
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Affiliation(s)
- Supriya Sharma
- Pharmacology and Toxicology Laboratory, Dietetics and Nutrition Technology Division, CSIR-Institute of Himalayan Bioresource Technology, Palampur-176061, Himachal Pradesh, India.,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad-201002, India
| | - Anil Kumar Rana
- Pharmacology and Toxicology Laboratory, Dietetics and Nutrition Technology Division, CSIR-Institute of Himalayan Bioresource Technology, Palampur-176061, Himachal Pradesh, India.,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad-201002, India
| | - Aditi Sharma
- Pharmacology and Toxicology Laboratory, Dietetics and Nutrition Technology Division, CSIR-Institute of Himalayan Bioresource Technology, Palampur-176061, Himachal Pradesh, India
| | - Damanpreet Singh
- Pharmacology and Toxicology Laboratory, Dietetics and Nutrition Technology Division, CSIR-Institute of Himalayan Bioresource Technology, Palampur-176061, Himachal Pradesh, India. .,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad-201002, India.
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13
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Palma JA, Martinez J, Millar Vernetti P, Ma T, Perez MA, Zhong J, Qian Y, Dutta S, Maina KN, Siddique I, Bitan G, Ades-Aron B, Shepherd TM, Kang UJ, Kaufmann H. mTOR Inhibition with Sirolimus in Multiple System Atrophy: A Randomized, Double-Blind, Placebo-Controlled Futility Trial and 1-Year Biomarker Longitudinal Analysis. Mov Disord 2022; 37:778-789. [PMID: 35040506 PMCID: PMC9018525 DOI: 10.1002/mds.28923] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Revised: 12/01/2021] [Accepted: 12/27/2021] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Multiple system atrophy (MSA) is a fatal neurodegenerative disease characterized by the aggregation of α-synuclein in glia and neurons. Sirolimus (rapamycin) is an mTOR inhibitor that promotes α-synuclein autophagy and reduces its associated neurotoxicity in preclinical models. OBJECTIVE To investigate the efficacy and safety of sirolimus in patients with MSA using a futility design. We also analyzed 1-year biomarker trajectories in the trial participants. METHODS Randomized, double-blind, parallel group, placebo-controlled clinical trial at the New York University of patients with probable MSA randomly assigned (3:1) to sirolimus (2-6 mg daily) for 48 weeks or placebo. Primary endpoint was change in the Unified MSA Rating Scale (UMSARS) total score from baseline to 48 weeks. (ClinicalTrials.gov NCT03589976). RESULTS The trial was stopped after a pre-planned interim analysis met futility criteria. Between August 15, 2018 and November 15, 2020, 54 participants were screened, and 47 enrolled and randomly assigned (35 sirolimus, 12 placebo). Of those randomized, 34 were included in the intention-to-treat analysis. There was no difference in change from baseline to week 48 between the sirolimus and placebo in UMSARS total score (mean difference, 2.66; 95% CI, -7.35-6.91; P = 0.648). There was no difference in UMSARS-1 and UMSARS-2 scores either. UMSARS scores changes were similar to those reported in natural history studies. Neuroimaging and blood biomarker results were similar in the sirolimus and placebo groups. Adverse events were more frequent with sirolimus. Analysis of 1-year biomarker trajectories in all participants showed that increases in blood neurofilament light chain (NfL) and reductions in whole brain volume correlated best with UMSARS progression. CONCLUSIONS Sirolimus for 48 weeks was futile to slow the progression of MSA and had no effect on biomarkers compared to placebo. One-year change in blood NfL and whole brain atrophy are promising biomarkers of disease progression for future clinical trials. © 2022 International Parkinson and Movement Disorder Society.
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Affiliation(s)
- Jose-Alberto Palma
- Department of Neurology, New York University Grossman School of Medicine, New York, NY, USA
| | - Jose Martinez
- Department of Neurology, New York University Grossman School of Medicine, New York, NY, USA
| | | | - Thong Ma
- Department of Neurology, New York University Grossman School of Medicine, New York, NY, USA
| | - Miguel A. Perez
- Department of Neurology, New York University Grossman School of Medicine, New York, NY, USA
| | - Judy Zhong
- Department of Population Health, Division of Biostatistics, New York University Grossman School of Medicine, New York, NY, USA
| | - Yingzhi Qian
- Department of Population Health, Division of Biostatistics, New York University Grossman School of Medicine, New York, NY, USA
| | - Suman Dutta
- Department of Neurology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA
| | - Katherine N. Maina
- Department of Neurology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA
| | - Ibrar Siddique
- Department of Neurology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA
| | - Gal Bitan
- Department of Neurology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA,Brain Research Institute, University of California, Los Angeles, CA, USA,Molecular Biology Institute, University of California, Los Angeles, CA, USA
| | - Benjamin Ades-Aron
- Department of Radiology, New York University Grossman School of Medicine, New York, NY, USA
| | - Timothy M. Shepherd
- Department of Radiology, New York University Grossman School of Medicine, New York, NY, USA
| | - Un Jung Kang
- Department of Neurology, New York University Grossman School of Medicine, New York, NY, USA
| | - Horacio Kaufmann
- Department of Neurology, New York University Grossman School of Medicine, New York, NY, USA
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14
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Siu VM, Hutson JR, Rupar CA. Clinical Conundrum: Polyhydramnios as a marker for a fetal genetic syndrome in the Canadian Old Order Mennonite population. Journal of Obstetrics and Gynaecology Canada 2022. [DOI: 10.1016/j.jogc.2022.01.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Revised: 01/17/2022] [Accepted: 01/19/2022] [Indexed: 10/19/2022]
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15
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Girodengo M, Ultanir SK, Bateman JM. Mechanistic target of rapamycin signaling in human nervous system development and disease. Front Mol Neurosci 2022; 15:1005631. [PMID: 36226315 PMCID: PMC9549271 DOI: 10.3389/fnmol.2022.1005631] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Accepted: 09/06/2022] [Indexed: 11/30/2022] Open
Abstract
Mechanistic target of rapamycin (mTOR) is a highly conserved serine/threonine kinase that regulates fundamental cellular processes including growth control, autophagy and metabolism. mTOR has key functions in nervous system development and mis-regulation of mTOR signaling causes aberrant neurodevelopment and neurological diseases, collectively called mTORopathies. In this mini review we discuss recent studies that have deepened our understanding of the key roles of the mTOR pathway in human nervous system development and disease. Recent advances in single-cell transcriptomics have been exploited to reveal specific roles for mTOR signaling in human cortical development that may have contributed to the evolutionary divergence from our primate ancestors. Cerebral organoid technology has been utilized to show that mTOR signaling is active in and regulates outer radial glial cells (RGCs), a population of neural stem cells that distinguish the human developing cortex. mTOR signaling has a well-established role in hamartoma syndromes such as tuberous sclerosis complex (TSC) and other mTORopathies. New ultra-sensitive techniques for identification of somatic mTOR pathway mutations have shed light on the neurodevelopmental origin and phenotypic heterogeneity seen in mTORopathy patients. These emerging studies suggest that mTOR signaling may facilitate developmental processes specific to human cortical development but also, when mis-regulated, cause cortical malformations and neurological disease.
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Affiliation(s)
- Marie Girodengo
- Kinases and Brain Development Lab, The Francis Crick Institute, London, United Kingdom.,King's College London, Maurice Wohl Clinical Neuroscience Institute, London, United Kingdom
| | - Sila K Ultanir
- Kinases and Brain Development Lab, The Francis Crick Institute, London, United Kingdom
| | - Joseph M Bateman
- King's College London, Maurice Wohl Clinical Neuroscience Institute, London, United Kingdom
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16
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Abstract
Despite recent advances in both the understanding and treatment of the epilepsies, the rate of refractory epilepsy has remained static for many years. However, given our greater understanding of the aetiology and genetic basis of many paediatric and adult epilepsies, there is now scope to expand treatment. In this review, we discuss the current and potential use of precision medicine in the genetic epilepsies of childhood. We will discuss how optimal control and a reduction in the rate of refractory seizures using targeted therapy could be developed and assessed. We propose a six-tier approach to defining precision therapeutics in epilepsy and discuss how this can be incorporated into a clinical trial design. The lower tiers (1-2) represent therapies in common usage that we know work for certain epilepsy syndromes but do not precisely target the underlying problem. They work to reduce seizures but do not directly or effectively attenuate the developmental phenotype. The higher tiers (5-6) are currently purely speculative and look to a future with highly disease-specific therapies based on correction of underlying genomic and proteomic issues. In order to achieve this, scientists will have to embark on a 'whole-omic' approach to understand the underlying pathophysiology in order to design a precision therapy. What this paper adds Epilepsy treatment is classified into six tiers depending on how precisely the mechanism of action addresses the aetiology. Tier 1 treatment is based on the historical response of certain epilepsy phenotypes to specific medication. Tier 6 concerns therapy targeting genes and networks that rescue the whole phenotype. Clinical trial infrastructure and population-based disease registries are necessary so that patients can participate in trials for novel precision therapies.
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Affiliation(s)
- Susan Byrne
- FutureNeuro SFI Research Centre and Department of Paediatrics, Royal College of Surgeons in Ireland, Dublin, Ireland.,Department of Paediatric Neurology, CHI at Crumlin, Dublin, Ireland
| | - Noelle Enright
- FutureNeuro SFI Research Centre and Department of Paediatrics, Royal College of Surgeons in Ireland, Dublin, Ireland.,Department of Paediatric Neurology, Great Ormond Street Hospital, London, UK
| | - Norman Delanty
- FutureNeuro SFI Research Centre and Department of Paediatrics, Royal College of Surgeons in Ireland, Dublin, Ireland.,Department of Neurology, Beaumont Hospital, Dublin, Ireland
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17
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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18
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Abstract
The presence of unprovoked, recurrent seizures, particularly when drug resistant and associated with cognitive and behavioral deficits, warrants investigation for an underlying genetic cause. This article provides an overview of the major classes of genes associated with epilepsy phenotypes divided into functional categories along with the recommended work-up and therapeutic considerations. Gene discovery in epilepsy supports counseling and anticipatory guidance but also opens the door for precision medicine guiding therapy with a focus on those with disease-modifying effects.
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Affiliation(s)
- Luis A Martinez
- Department of Pediatrics, Section of Pediatric Neurology and Developmental Neuroscience, Baylor College of Medicine, Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, 1250 Moursund Drive, Houston, TX 77030, USA
| | - Yi-Chen Lai
- Department of Pediatrics, Section of Pediatric Critical Care Medicine, Baylor College of Medicine, Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, 1250 Moursund Drive, Houston, TX 77030, USA
| | - J Lloyd Holder
- Department of Pediatrics, Section of Pediatric Neurology and Developmental Neuroscience, Baylor College of Medicine, Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, 1250 Moursund Drive, Houston, TX 77030, USA
| | - Anne E Anderson
- Department of Pediatrics, Section of Pediatric Neurology and Developmental Neuroscience, Baylor College of Medicine, Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, 1250 Moursund Drive, Houston, TX 77030, USA.
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19
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Nguyen LH, Bordey A. Corrigendum: Convergent and Divergent Mechanisms of Epileptogenesis in mTORopathies. Front Neuroanat 2021; 15:715363. [PMID: 34295225 PMCID: PMC8290855 DOI: 10.3389/fnana.2021.715363] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Accepted: 05/28/2021] [Indexed: 01/16/2023] Open
Affiliation(s)
- Lena H Nguyen
- Department of Neurosurgery, Yale School of Medicine, Yale University, New Haven, CT, United States.,Department of Cellular & Molecular Physiology, Yale School of Medicine, Yale University, New Haven, CT, United States
| | - Angélique Bordey
- Department of Neurosurgery, Yale School of Medicine, Yale University, New Haven, CT, United States.,Department of Cellular & Molecular Physiology, Yale School of Medicine, Yale University, New Haven, CT, United States
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20
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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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21
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Liaci C, Camera M, Caslini G, Rando S, Contino S, Romano V, Merlo GR. Neuronal Cytoskeleton in Intellectual Disability: From Systems Biology and Modeling to Therapeutic Opportunities. Int J Mol Sci 2021; 22:ijms22116167. [PMID: 34200511 PMCID: PMC8201358 DOI: 10.3390/ijms22116167] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Revised: 05/25/2021] [Accepted: 06/04/2021] [Indexed: 02/06/2023] Open
Abstract
Intellectual disability (ID) is a pathological condition characterized by limited intellectual functioning and adaptive behaviors. It affects 1–3% of the worldwide population, and no pharmacological therapies are currently available. More than 1000 genes have been found mutated in ID patients pointing out that, despite the common phenotype, the genetic bases are highly heterogeneous and apparently unrelated. Bibliomic analysis reveals that ID genes converge onto a few biological modules, including cytoskeleton dynamics, whose regulation depends on Rho GTPases transduction. Genetic variants exert their effects at different levels in a hierarchical arrangement, starting from the molecular level and moving toward higher levels of organization, i.e., cell compartment and functions, circuits, cognition, and behavior. Thus, cytoskeleton alterations that have an impact on cell processes such as neuronal migration, neuritogenesis, and synaptic plasticity rebound on the overall establishment of an effective network and consequently on the cognitive phenotype. Systems biology (SB) approaches are more focused on the overall interconnected network rather than on individual genes, thus encouraging the design of therapies that aim to correct common dysregulated biological processes. This review summarizes current knowledge about cytoskeleton control in neurons and its relevance for the ID pathogenesis, exploiting in silico modeling and translating the implications of those findings into biomedical research.
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Affiliation(s)
- Carla Liaci
- Department of Molecular Biotechnology and Health Sciences, University of Torino, Via Nizza 52, 10126 Torino, Italy; (C.L.); (M.C.); (G.C.); (S.R.)
| | - Mattia Camera
- Department of Molecular Biotechnology and Health Sciences, University of Torino, Via Nizza 52, 10126 Torino, Italy; (C.L.); (M.C.); (G.C.); (S.R.)
| | - Giovanni Caslini
- Department of Molecular Biotechnology and Health Sciences, University of Torino, Via Nizza 52, 10126 Torino, Italy; (C.L.); (M.C.); (G.C.); (S.R.)
| | - Simona Rando
- Department of Molecular Biotechnology and Health Sciences, University of Torino, Via Nizza 52, 10126 Torino, Italy; (C.L.); (M.C.); (G.C.); (S.R.)
| | - Salvatore Contino
- Department of Engineering, University of Palermo, Viale delle Scienze Ed. 8, 90128 Palermo, Italy;
| | - Valentino Romano
- Department of Biological, Chemical and Pharmaceutical Sciences and Technologies (STEBICEF), University of Palermo, Viale delle Scienze Ed. 16, 90128 Palermo, Italy;
| | - Giorgio R. Merlo
- Department of Molecular Biotechnology and Health Sciences, University of Torino, Via Nizza 52, 10126 Torino, Italy; (C.L.); (M.C.); (G.C.); (S.R.)
- Correspondence: ; Tel.: +39-0116706449; Fax: +39-0116706432
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22
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Abstract
The mechanistic target of rapamycin (mTOR) is a kinase at the center of an evolutionarily conserved signaling pathway that orchestrates cell growth and metabolism. mTOR responds to an array of intra- and extracellular stimuli and in turn controls multiple cellular anabolic and catabolic processes. Aberrant mTOR activity is associated with numerous diseases, with particularly profound impact on the nervous system. mTOR is found in two protein complexes, mTOR complex 1 (mTORC1) and 2 (mTORC2), which are governed by different upstream regulators and have distinct cellular actions. Mutations in genes encoding for mTOR regulators result in a collection of neurodevelopmental disorders known as mTORopathies. While these disorders can affect multiple organs, neuropsychiatric conditions such as epilepsy, intellectual disability, and autism spectrum disorder have a major impact on quality of life. The neuropsychiatric aspects of mTORopathies have been particularly challenging to treat in a clinical setting. Current therapeutic approaches center on rapamycin and its analogs, drugs that are administered systemically to inhibit mTOR activity. While these drugs show some clinical efficacy, adverse side effects, incomplete suppression of mTOR targets, and lack of specificity for mTORC1 or mTORC2 may limit their utility. An increased understanding of the neurobiology of mTOR and the underlying molecular, cellular, and circuit mechanisms of mTOR-related disorders will facilitate the development of improved therapeutics. Animal models of mTORopathies have helped unravel the consequences of mTOR pathway mutations in specific brain cell types and developmental stages, revealing an array of disease-related phenotypes. In this review, we discuss current progress and potential future directions for the therapeutic treatment of mTORopathies with a focus on findings from genetic mouse models.
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Affiliation(s)
- Vasiliki Karalis
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, California, USA
| | - Helen S Bateup
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, California, USA
- Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, California, USA
- Chan Zuckerberg Biohub, San Francisco, California, USA
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23
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Dang LT, Vaid S, Lin G, Swaminathan P, Safran J, Loughman A, Lee M, Glenn T, Majolo F, Crino PB, Parent JM. STRADA-mutant human cortical organoids model megalencephaly and exhibit delayed neuronal differentiation. Dev Neurobiol 2021; 81:696-709. [PMID: 33619909 DOI: 10.1002/dneu.22816] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 02/18/2021] [Accepted: 02/19/2021] [Indexed: 12/31/2022]
Abstract
Genetic diseases involving overactivation of the mechanistic target of rapamycin (mTOR) pathway, so-called "mTORopathies," often manifest with malformations of cortical development (MCDs), epilepsy, and cognitive impairment. How mTOR pathway hyperactivation results in abnormal human cortical development is poorly understood. To study the effect of mTOR hyperactivity on early stages of cortical development, we focused on Pretzel Syndrome (polyhydramnios, megalencephaly, symptomatic epilepsy; PMSE syndrome), a rare mTORopathy caused by homozygous germline mutations in the STRADA gene. We developed a human cortical organoid (hCO) model of PMSE and examined morphology and size for the first 2 weeks of organoid growth, and cell type composition at weeks 2, 8, and 12 of differentiation. In the second week, PMSE hCOs enlarged more rapidly than controls and displayed an abnormal Wnt pathway-dependent increase in neural rosette structures. PMSE hCOs also exhibited delayed neurogenesis, decreased subventricular zone progenitors, increased proliferation and cell death, and an abnormal architecture of primary cilia. At week 8, PMSE hCOs had fewer deep layer neurons. By week 12, neurogenesis recovered in PMSE organoids, but they displayed increased outer radial glia, a cell type thought to contribute to the expansion of the human cerebral cortex. Together, these findings suggest that megalencephaly in PMSE arises from the expansion of neural stem cells in early corticogenesis and potentially also from increased outer radial glial at later gestational stages. The delayed neuronal differentiation in PMSE organoids demonstrates the important role the mTOR pathway plays in the maintenance and expansion of the stem cell pool.
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Affiliation(s)
- Louis T Dang
- Department of Pediatrics, Michigan Medicine, Ann Arbor, MI, USA.,Department of Neurology, Michigan Medicine, Ann Arbor, MI, USA.,Michigan Neuroscience Institute, Michigan Medicine, Ann Arbor, MI, USA
| | - Shivanshi Vaid
- Department of Pediatrics, Michigan Medicine, Ann Arbor, MI, USA.,Michigan Neuroscience Institute, Michigan Medicine, Ann Arbor, MI, USA
| | - Grace Lin
- Department of Neurology, Michigan Medicine, Ann Arbor, MI, USA.,Michigan Neuroscience Institute, Michigan Medicine, Ann Arbor, MI, USA
| | | | - Jordan Safran
- Department of Pediatrics, Michigan Medicine, Ann Arbor, MI, USA
| | - Anna Loughman
- Department of Pediatrics, Michigan Medicine, Ann Arbor, MI, USA
| | - Monica Lee
- Department of Pediatrics, Michigan Medicine, Ann Arbor, MI, USA
| | - Trevor Glenn
- Department of Neurology, Michigan Medicine, Ann Arbor, MI, USA
| | - Fernanda Majolo
- Department of Neurology, Michigan Medicine, Ann Arbor, MI, USA
| | - Peter B Crino
- Department of Neurology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Jack M Parent
- Department of Neurology, Michigan Medicine, Ann Arbor, MI, USA.,Michigan Neuroscience Institute, Michigan Medicine, Ann Arbor, MI, USA.,Neurology Service, VA Ann Arbor Healthcare System, Ann Arbor, MI, USA
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24
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Abstract
Hyperactivation of the mechanistic target of rapamycin complex 1 (mTORC1) due to mutations in genes along the PI3K-mTOR pathway and the GATOR1 complex causes a spectrum of neurodevelopmental disorders (termed mTORopathies) associated with malformation of cortical development and intractable epilepsy. Despite these gene variants’ converging impact on mTORC1 activity, emerging findings suggest that these variants contribute to epilepsy through both mTORC1-dependent and -independent mechanisms. Here, we review the literature on in utero electroporation-based animal models of mTORopathies, which recapitulate the brain mosaic pattern of mTORC1 hyperactivity, and compare the effects of distinct PI3K-mTOR pathway and GATOR1 complex gene variants on cortical development and epilepsy. We report the outcomes on cortical pyramidal neuronal placement, morphology, and electrophysiological phenotypes, and discuss some of the converging and diverging mechanisms responsible for these alterations and their contribution to epileptogenesis. We also discuss potential therapeutic strategies for epilepsy, beyond mTORC1 inhibition with rapamycin or everolimus, that could offer personalized medicine based on the gene variant.
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Affiliation(s)
- Lena H Nguyen
- Department of Neurosurgery, Yale School of Medicine, Yale University, New Haven, CT, United States.,Department of Cellular & Molecular Physiology, Yale School of Medicine, Yale University, New Haven, CT, United States
| | - Angélique Bordey
- Department of Neurosurgery, Yale School of Medicine, Yale University, New Haven, CT, United States.,Department of Cellular & Molecular Physiology, Yale School of Medicine, Yale University, New Haven, CT, United States
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25
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Aerden M, Vallaeys L, Holvoet M, De Waele L, Van Den Bogaert K, Devriendt K. Homozygous missense STRADA mutation in a patient with polyhydramnios, megalencephaly and symptomatic epilepsy syndrome. Clin Dysmorphol 2021; 30:121-4. [PMID: 33605605 DOI: 10.1097/MCD.0000000000000368] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Homozygous or compound heterozygous mutations in STRADA cause polyhydramnios, megalencephaly and symptomatic epilepsy syndrome (PMSE), with additional features of distinctive facial traits and severe developmental delay or intellectual disability. This syndrome was first defined in 16 Old Order Mennonite patients, carrying a homozygous STRADA deletion of exon 9-13. Five additional PMSE patients have been reported since, each of them with loss-of-function variants. We report a female patient with the typical clinical features of PMSE, homozygous for a novel STRADA missense mutation c.792T>A (p.Ser264Arg) in exon 10. This finding contributes to the further delineation of the phenotype of PMSE.
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26
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Goldstein HE, Hauptman JS. The Putative Role of mTOR Inhibitors in Non-tuberous Sclerosis Complex-Related Epilepsy. Front Neurol 2021; 12:639319. [PMID: 33643212 PMCID: PMC7907183 DOI: 10.3389/fneur.2021.639319] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Accepted: 01/25/2021] [Indexed: 11/13/2022] Open
Abstract
Epilepsy affects ~5 out of every 10,000 children per year. Up to one-third of these children have medically refractory epilepsy, with limited to no options for improved seizure control. mTOR, a ubiquitous 289 kDa serine/threonine kinase in the phosphatidylinositol 3-kinase (PI3K)-related kinases (PIKK) family, is dysregulated in a number of human diseases, including tuberous sclerosis complex (TSC) and epilepsy. In cell models of epilepsy and TSC, rapamycin, an mTOR inhibitor, has been shown to decrease seizure frequency and duration, and positively affect cell growth and morphology. Rapamycin has also been shown to prevent or improve epilepsy and prolong survival in animal models of TSC. To date, clinical studies looking at the effects of mTOR inhibitors on the reduction of seizures have mainly focused on patients with TSC. Everolimus (Novartis Pharmaceuticals), a chemically modified rapamycin derivative, has been shown to reduce seizure frequency with reasonable safety and tolerability. Mutations in mTOR or the mTOR pathway have been found in hemimegalencephaly (HME) and focal cortical dysplasias (FCDs), both of which are highly correlated with medically refractory epilepsy. Given the evidence to date, a logical next step is to investigate the role of mTOR inhibitors in the treatment of children with medically refractory non-TSC epilepsy, particularly those children who have also failed resective surgery.
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Affiliation(s)
- Hannah E Goldstein
- Department of Neurological Surgery, University of Washington, Seattle, WA, United States.,Department of Neurosurgery, Seattle Children's Hospital, Seattle, WA, United States
| | - Jason S Hauptman
- Department of Neurological Surgery, University of Washington, Seattle, WA, United States.,Department of Neurosurgery, Seattle Children's Hospital, Seattle, WA, United States
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27
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Sidira C, Vargiami E, Dragoumi P, Zafeiriou DI. Hemimegalencephaly and tuberous sclerosis complex: A rare yet challenging association. Eur J Paediatr Neurol 2021; 30:58-65. [PMID: 33387903 DOI: 10.1016/j.ejpn.2020.12.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 10/20/2020] [Accepted: 12/17/2020] [Indexed: 12/18/2022]
Abstract
Hemimegalencephaly is a rare malformation of cortical development characterised by enlargement of one cerebral hemisphere. The association between hemimegalencephaly and tuberous sclerosis complex, an autosomal dominant genetic disorder, is uncommon and has so far been reported only in a few cases. Intractable epilepsy and severe developmental delay are typical clinical manifestations. Aberrant activation of the mTOR signalling pathway is considered to be the hallmark of the pathogenesis of these two disorders. Thus, mTOR inhibitors such as everolimus represent a promising therapeutic approach to mTOR-associated manifestations. We present a thorough literature review of the association between hemimegaloencephaly and tuberous sclerosis complex.
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Affiliation(s)
- Christina Sidira
- 1st Paediatric Department, Developmental Centre "A. Fokas", Aristotle University of Thessaloniki, "Hippokration" General Hospital, Thessaloniki, Greece
| | - Efthymia Vargiami
- 1st Paediatric Department, Developmental Centre "A. Fokas", Aristotle University of Thessaloniki, "Hippokration" General Hospital, Thessaloniki, Greece
| | - Pinelopi Dragoumi
- 1st Paediatric Department, Developmental Centre "A. Fokas", Aristotle University of Thessaloniki, "Hippokration" General Hospital, Thessaloniki, Greece
| | - Dimitrios I Zafeiriou
- 1st Paediatric Department, Developmental Centre "A. Fokas", Aristotle University of Thessaloniki, "Hippokration" General Hospital, Thessaloniki, Greece.
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28
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Hadouiri N, Darmency V, Guibaud L, Arzimanoglou A, Sorlin A, Carmignac V, Rivière JB, Huet F, Luu M, Bardou M, Thauvin-Robinet C, Vabres P, Faivre L. Compassionate use of everolimus for refractory epilepsy in a patient with MTOR mosaic mutation. Eur J Med Genet 2020; 63:104036. [PMID: 32805448 DOI: 10.1016/j.ejmg.2020.104036] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Revised: 06/16/2020] [Accepted: 08/08/2020] [Indexed: 10/23/2022]
Abstract
The MTOR gene encodes the mechanistic target of rapamycin (mTOR), which is a core component of the PI3K-AKT-mTOR signaling pathway. Postzygotic MTOR variants result in various mosaic phenotypes, referred to in OMIM as Smith-Kinsgmore syndrome or focal cortical dysplasia. We report here the case of a patient, with an MTOR mosaic gain-of-function variant (p.Glu2419Lys) in the DNA of 41% skin cells, who received compassionate off-label treatment with everolimus for refractory epilepsy. This 12-year-old-girl presented with psychomotor regression, intractable seizures, hypopigmentation along Blaschko's lines (hypomelanosis of Ito), asymmetric regional body overgrowth, and ocular anomalies, as well as left cerebral hemispheric hypertrophy with some focal underlying migration disorders. In response to the patient's increasingly frequent epileptic seizures, everolimus was initiated (after approval from the hospital ethics committee) at 5 mg/day and progressively increased to 12.5 mg/day. After 5 months of close monitoring (including neuropsychological and electroencephalographic assessment), no decrease in seizure frequency was observed. Though the physiopathological rationale was good, no significant clinical response was noticed under everolimus treatment. A clinical trial would be needed to draw conclusions, but, because the phenotype is extremely rare, it would certainly need to be conducted on an international scale.
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Affiliation(s)
- Nawale Hadouiri
- Centre de Génétique et Centre de Référence Anomalies du Développement et Syndromes Malformatifs de l'Interrégion Est, CHU Dijon Bourgogne, 21079, Dijon, France
| | - Veronique Darmency
- Service de Neurophysiologie Clinique, Hôpital d'Enfants, CHU Dijon Bourgogne, 21079, Dijon, France
| | - Laurent Guibaud
- Radiologie Pédiatrique, Hôpital Femme Mère Enfant (HFME), Bron, France
| | - Alexis Arzimanoglou
- Service d'épileptologie Clinique, des Troubles du Sommeil et de Neurologie Fonctionnelle de l'enfant, Coordinateur du Réseau Européen pour les épilepsies Rares et Complexes, ERN EpiCARE, HCL - GH Est, Hôpital Femme Mère Enfant, Bron, France
| | - Arthur Sorlin
- Centre de Génétique et Centre de Référence Anomalies du Développement et Syndromes Malformatifs de l'Interrégion Est, CHU Dijon Bourgogne, 21079, Dijon, France; Génétique des Anomalies du Développement, UMR1231, Université de Bourgogne, 21079, Dijon, France
| | - Virginie Carmignac
- Génétique des Anomalies du Développement, UMR1231, Université de Bourgogne, 21079, Dijon, France
| | - Jean-Baptiste Rivière
- Génétique des Anomalies du Développement, UMR1231, Université de Bourgogne, 21079, Dijon, France; Fédération Hospitalo-Universitaire Médecine Translationnelle et Anomalies du Développement (TRANSLAD), CHU Dijon Bourgogne, 21079, Dijon, France
| | - Frédéric Huet
- Service de Neurophysiologie Clinique, Hôpital d'Enfants, CHU Dijon Bourgogne, 21079, Dijon, France
| | - Maxime Luu
- Centre d'Investigation Clinique Plurithématique, CHU Dijon Bourgogne, 21079, Dijon, France
| | - Marc Bardou
- Centre d'Investigation Clinique Plurithématique, CHU Dijon Bourgogne, 21079, Dijon, France
| | - Christel Thauvin-Robinet
- Génétique des Anomalies du Développement, UMR1231, Université de Bourgogne, 21079, Dijon, France; Fédération Hospitalo-Universitaire Médecine Translationnelle et Anomalies du Développement (TRANSLAD), CHU Dijon Bourgogne, 21079, Dijon, France; Centre de Référence Déficiences Intellectuelles de Causes Rares Défi-Bourgogne, CHU Dijon Bourgogne, 21079, Dijon, France
| | - Pierre Vabres
- Génétique des Anomalies du Développement, UMR1231, Université de Bourgogne, 21079, Dijon, France; Fédération Hospitalo-Universitaire Médecine Translationnelle et Anomalies du Développement (TRANSLAD), CHU Dijon Bourgogne, 21079, Dijon, France; Centre de Référence des Maladies Rares de la Peau et des Muqueuses d'origine Génétique (MAGEC), CHU Dijon Bourgogne, 21079, Dijon, France
| | - Laurence Faivre
- Centre de Génétique et Centre de Référence Anomalies du Développement et Syndromes Malformatifs de l'Interrégion Est, CHU Dijon Bourgogne, 21079, Dijon, France; Génétique des Anomalies du Développement, UMR1231, Université de Bourgogne, 21079, Dijon, France; Fédération Hospitalo-Universitaire Médecine Translationnelle et Anomalies du Développement (TRANSLAD), CHU Dijon Bourgogne, 21079, Dijon, France.
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29
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Hoffman CE, Parker WE, Rapoport BI, Zhao M, Ma H, Schwartz TH. Innovations in the Neurosurgical Management of Epilepsy. World Neurosurg 2020; 139:775-788. [PMID: 32689698 DOI: 10.1016/j.wneu.2020.03.031] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Accepted: 03/02/2020] [Indexed: 10/23/2022]
Abstract
Technical limitations and clinical challenges have historically limited the diagnostic tools and treatment methods available for surgical approaches to the management of epilepsy. By contrast, recent technological innovations in several areas hold significant promise in improving outcomes and decreasing morbidity. We review innovations in the neurosurgical management of epilepsy in several areas, including wireless recording and stimulation systems (particularly responsive neurostimulation [NeuroPace]), conformal electrodes for high-resolution electrocorticography, robot-assisted stereotactic surgery, optogenetics and optical imaging methods, novel positron emission tomography ligands, and new applications of focused ultrasonography. Investigation into genetic causes of and susceptibilities to epilepsy has introduced a new era of precision medicine, enabling the understanding of cell signaling mechanisms underlying epileptic activity as well as patient-specific molecularly targeted treatment options. We discuss the emerging path to individualized treatment plans, predicted outcomes, and improved selection of effective interventions, on the basis of these developments.
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Affiliation(s)
- Caitlin E Hoffman
- Department of Neurological Surgery, Weill Cornell Medical College, NewYork-Presbyterian Hospital, New York, New York, USA.
| | - Whitney E Parker
- Department of Neurological Surgery, Weill Cornell Medical College, NewYork-Presbyterian Hospital, New York, New York, USA
| | - Benjamin I Rapoport
- Department of Neurological Surgery, Weill Cornell Medical College, NewYork-Presbyterian Hospital, New York, New York, USA
| | - Mingrui Zhao
- Department of Neurological Surgery, Weill Cornell Medical College, NewYork-Presbyterian Hospital, New York, New York, USA
| | - Hongtao Ma
- Department of Neurological Surgery, Weill Cornell Medical College, NewYork-Presbyterian Hospital, New York, New York, USA
| | - Theodore H Schwartz
- Department of Neurological Surgery, Weill Cornell Medical College, NewYork-Presbyterian Hospital, New York, New York, USA
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30
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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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31
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Dang LT, Glanowska KM, Iffland Ii PH, Barnes AE, Baybis M, Liu Y, Patino G, Vaid S, Streicher AM, Parker WE, Kim S, Moon UY, Henry FE, Murphy GG, Sutton M, Parent JM, Crino PB. Multimodal Analysis of STRADA Function in Brain Development. Front Cell Neurosci 2020; 14:122. [PMID: 32457579 PMCID: PMC7227375 DOI: 10.3389/fncel.2020.00122] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Accepted: 04/14/2020] [Indexed: 12/22/2022] Open
Abstract
mTORopathies are a heterogeneous group of neurological disorders characterized by malformations of cortical development (MCD), enhanced cellular mechanistic target of rapamycin (mTOR) signaling, and epilepsy that results from mutations in mTOR pathway regulatory genes. Homozygous mutations (del exon 9–13) in the pseudokinase STE20-related kinase adaptor alpha (STRAD-α; STRADA), an mTOR modulator, are associated with Pretzel Syndrome (PS), a neurodevelopmental disorder within the Old Order Mennonite Community characterized by megalencephaly, intellectual disability, and intractable epilepsy. To study the cellular mechanisms of STRADA loss, we generated CRISPR-edited Strada mouse N2a cells, a germline mouse Strada knockout (KO−/−) strain, and induced pluripotent stem cell (iPSC)-derived neurons from PS individuals harboring the STRADA founder mutation. Strada KO in vitro leads to enhanced mTOR signaling and iPSC-derived neurons from PS individuals exhibit enhanced cell size and mTOR signaling activation, as well as subtle alterations in electrical firing properties e.g., increased input resistance, a more depolarized resting membrane potential, and decreased threshold for action potential (AP) generation. Strada−/− mice exhibit high rates of perinatal mortality and out of more than 100 litters yielding both WT and heterozygous pups, only eight Strada−/− animals survived past P5. Strada−/− mice are hypotonic and tremulous. Histopathological examination (n = 5 mice) revealed normal gross brain organization and lamination but all had ventriculomegaly. Ectopic neurons were seen in all five Strada−/− brains within the subcortical white matter mirroring what is observed in human PS brain tissue. These distinct experimental platforms demonstrate that STRADA modulates mTOR signaling and is a key regulator of cell size, neuronal excitability, and cortical lamination.
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Affiliation(s)
- Louis T Dang
- Department of Neurology, Michigan Medicine, Ann Arbor, MI, United States.,Department of Pediatrics, Michigan Medicine, Ann Arbor, MI, United States
| | - Katarzyna M Glanowska
- Department of Neurology, Michigan Medicine, Ann Arbor, MI, United States.,Michigan Neuroscience Institute, Michigan Medicine, Ann Arbor, MI, United States
| | - Philip H Iffland Ii
- Department of Neurology, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Allan E Barnes
- Department of Neurology, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Marianna Baybis
- Department of Neurology, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Yu Liu
- Department of Neurology, Michigan Medicine, Ann Arbor, MI, United States
| | - Gustavo Patino
- Department of Neurology, Michigan Medicine, Ann Arbor, MI, United States
| | - Shivanshi Vaid
- Department of Neurology, Michigan Medicine, Ann Arbor, MI, United States.,Department of Pediatrics, Michigan Medicine, Ann Arbor, MI, United States
| | | | - Whitney E Parker
- Department of Neurosurgery, Weill-Cornell Medical Center, New York, NY, United States
| | - Seonhee Kim
- Louis Katz School of Medicine, Temple University, Philadelphia, PA, United States
| | - Uk Yeol Moon
- Louis Katz School of Medicine, Temple University, Philadelphia, PA, United States
| | - Frederick E Henry
- Michigan Neuroscience Institute, Michigan Medicine, Ann Arbor, MI, United States.,Department of Molecular, and Integrative Physiology, Michigan Medicine, Ann Arbor, MI, United States
| | - Geoffrey G Murphy
- Michigan Neuroscience Institute, Michigan Medicine, Ann Arbor, MI, United States.,Department of Molecular, and Integrative Physiology, Michigan Medicine, Ann Arbor, MI, United States
| | - Michael Sutton
- Michigan Neuroscience Institute, Michigan Medicine, Ann Arbor, MI, United States.,Department of Molecular, and Integrative Physiology, Michigan Medicine, Ann Arbor, MI, United States
| | - Jack M Parent
- Department of Neurology, Michigan Medicine, Ann Arbor, MI, United States.,Neurology Service, VA Ann Arbor Healthcare System, Ann Arbor, MI, United States
| | - Peter B Crino
- Department of Neurology, University of Maryland School of Medicine, Baltimore, MD, United States
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Jiang Q, Gu S. Sevoflurane Postconditioning Reduces Hypoxia-Reoxygenation Injury in H9C2 Embryonic Rat Cardiomyocytes and Targets the STRADA Gene by Upregulating microRNA-107. Med Sci Monit 2020; 26:e920849. [PMID: 32332694 PMCID: PMC7197225 DOI: 10.12659/msm.920849] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
BACKGROUND Sevoflurane as a widely used inhalational general anesthetic that also has a cardioprotective role in hypoxia-reoxygenation (H/R) injury. This study aimed to investigate the effects of microRNA-107 (miR-107) on sevoflurane postconditioning (SpostC) in H9C2 embryonic rat cardiomyocytes and to use bioinformatics analysis to identify the molecular basis of cardioprotection from sevoflurane in human cardiac tissue. MATERIAL AND METHODS The STRADA gene was identified from the Gene Expression Omnibus (GEO) database. H9C2 embryonic rat cardiomyocytes were cultured with sevoflurane. Quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot were used to measure the mRNA expression and protein expression of STRADA and miR-107 in H9C2 cells. TargetScanHuman version 7.2 was used to identify the target gene of miR-107 and to predict the STRADA 3'-UTR binding site of miR-107. The dual-luciferase reporter assay measured the relative luciferase activity. The cell proliferation rate and cell apoptosis were measured using the MTT assay and flow cytometry, respectively. RESULTS H/R injury in H9C2 cells following SpostC resulted in increased expression of miR-107 and reduced expression of STRADA. Specific binding of miR-107 was identified to STRADA 3'-UTR. Upregulation of the miR-107 in SpostC H/R injured H9C2 cells promoted cell proliferation, reduced cell apoptosis, and downregulating the protein expression of caspase-3. STRADA overexpression reduced the effects of a miR-107 mimic on SpostC. CONCLUSIONS SpostC reduced H/R injury in H9C2 embryonic rat cardiomyocytes by targeting the STRADA gene and by upregulating the expression of microRNA-107.
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Affiliation(s)
- Qun Jiang
- Department of Pain Medicine, Affiliated Hospital of Jianghan University, Wuhan, Hubei, China (mainland)
| | - Shan Gu
- Department of Anesthesiology, Hubei Provincial Hospital of Traditional Chinese Medicine, Wuhan, Hubei, China (mainland).,Hubei Province Academy of Traditional Chinese Medicine, Wuhan, Hubei, China (mainland)
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Abstract
PURPOSE OF REVIEW The purpose of this review is to summarize and discuss current options and new advances in the treatment of sleep-related hypermotor epilepsy (SHE), focusing on pharmacological and surgical treatments. RECENT FINDINGS Carbamazepine (CBZ) has traditionally been regarded as the first-line treatment option in SHE patients. In patients showing an unsatisfactory response to monotherapy, topiramate (TPM), lacosamide (LCM) and acetazolamide (ACZ) could be reasonable add-on strategies. The increasing understanding of the role of neuronal nicotinic acetylcholine receptor (nAChR) in SHE pathophysiology has led to the evaluation of compounds able to modulate this receptor system, including nicotine patches and fenofibrate. Despite polytherapy with two or more antiepileptic drugs (AEDs), about one-third of SHE patients suffer from drug-resistant seizures. In selected drug-resistant patients, epilepsy surgery is a therapeutic approach that offers high probability of recovery, with up to two-third of patients becoming seizure-free after resection of the epileptogenic zone. An evidence-based approach from randomized placebo-controlled trials in SHE patients is lacking, and current treatment recommendations are based only on case reports and small series. Furthermore, most of these case reports and case series involve patients with a known genetic defect, which only accounts for a small proportion of SHE patients. Therefore, a prospective study in a large cohort of sporadic SHE patients is necessary in order to provide clinicians with an evidence-based treatment for this rare form of epilepsy. An early and effective anti-epileptic treatment is mandatory for SHE patients, in order to prevent the risk of increasing seizure frequency throughout the disease course with relevant impact on patients' cognitive profile and daytime performances.
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Affiliation(s)
- Gian Maria Asioli
- Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
| | - Simone Rossi
- Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
| | - Francesca Bisulli
- Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy.,IRCCS, Istituto delle Scienze Neurologiche di Bologna, Bologna, Italy
| | - Laura Licchetta
- Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy.,IRCCS, Istituto delle Scienze Neurologiche di Bologna, Bologna, Italy
| | - Paolo Tinuper
- Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy.,IRCCS, Istituto delle Scienze Neurologiche di Bologna, Bologna, Italy
| | - Federica Provini
- Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy. .,IRCCS, Istituto delle Scienze Neurologiche di Bologna, Bologna, Italy. .,Department of Biomedical and Neuromotor Sciences, IRCCS, Istituto delle Scienze Neurologiche, Via Altura, 3, 40123, Bologna, Italy.
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Abstract
The mechanistic target of rapamycin (mTOR) pathway plays a critical role in brain development, neuronal shape and size, and synaptic plasticity, as well as learning and memory. Mutations in mTOR pathway genes (MPG) cause malformations of cortical development (MCDs) that are highly associated with often intractable epilepsy, thus highlighting an association between the mTOR pathway and establishment of the epileptic network. A growing body of preclinical evidence in in vitro and rodent model systems suggests that mTOR signaling may be altered in status epilepticus (SE) and that modulation of mTOR activation with mTOR inhibitors such as rapamycin (sirolimus) could provide new therapeutic avenues for treatment of both refractory epilepsy and SE. Rapamycin may have ubiquitous effects on all neuronal subtypes as well as astrocytes and seems to prevent the development of seizures following experimentally induced SE. To date, there have been no human studies focused on mTOR signaling in SE, but clearly, preclinical data support investigation into this pivotal cell signaling pathway. Thus, modulation of the mTOR pathway may provide a new strategy for treatment of SE and could have implications for the prevention of epilepsy in patients with SE. This article is part of the Special Issue "Proceedings of the 7th London-Innsbruck Colloquium on Status Epilepticus and Acute Seizures".
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Affiliation(s)
- Peter B Crino
- Department of Neurology, University of Maryland School of Medicine, 110 S. Paca St., Baltimore, MD 21201, United States of America.
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Iffland PH, Carson V, Bordey A, Crino PB. GATORopathies: The role of amino acid regulatory gene mutations in epilepsy and cortical malformations. Epilepsia 2019; 60:2163-2173. [PMID: 31625153 PMCID: PMC7155771 DOI: 10.1111/epi.16370] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Revised: 09/20/2019] [Accepted: 09/20/2019] [Indexed: 12/11/2022]
Abstract
The mechanistic target of rapamycin (mTOR) pathway has been implicated in a growing number of malformations of cortical development (MCD) associated with intractable epilepsy. Mutations in single genes encoding mTOR pathway regulatory proteins have been linked to MCD such as focal cortical dysplasia (FCD) types IIa and IIb, hemimegalencephaly (HME), and megalencephaly. Recent studies have demonstrated that the GATOR1 protein complex, comprised of DEPDC5, NPRL3, and NPRL2, plays a pivotal role in regulating mTOR signaling in response to cellular amino acid levels and that mutations in DEPDC5, NPRL3, or NPRL2 are linked to FCD, HME, and seizures. Histopathological analysis of FCD and HME tissue specimens resected from individuals harboring DEPDC5, NPRL3, or NPRL2 gene mutations reveals hyperactivation of mTOR pathway signaling. Family pedigrees carrying mutations in either DEPDC5 or NPRL3 share clinical phenotypes of epilepsy and MCD, as well as intellectual and neuropsychiatric disabilities. Interestingly, some individuals with seizures associated with DEPDC5, NPRL3, or NPRL2 variants exhibit normal brain imaging suggesting either occult MCD or a role for these genes in non-lesional neocortical epilepsy. Mouse models resulting from knockdown or knockout of either Depdc5 or Nprl3 exhibit altered cortical lamination, neuronal dysmorphogenesis, and enhanced neuronal excitability as reported in models resulting from direct mTOR activation through expression of its canonical activator RHEB. The role of the GATOR1 proteins in regulating mTOR signaling suggest plausible options for mTOR inhibition in the treatment of epilepsy associated with mutations in DEPDC5, NPRL3, or NPRL2.
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Affiliation(s)
- Philip H. Iffland
- Department of Neurology, University of Maryland School of Medicine, Baltimore, Maryland
| | - Vincent Carson
- The Clinic for Special Children, Strasburg, Pennsylvania
| | - Angelique Bordey
- Department of Neurosurgery, Yale University School of Medicine, New Haven, Connecticut
| | - Peter B. Crino
- Department of Neurology, University of Maryland School of Medicine, Baltimore, Maryland
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Abstract
The mechanistic target of rapamycin (mTOR) pathway coordinates the metabolic activity of eukaryotic cells through environmental signals, including nutrients, energy, growth factors, and oxygen. In the nervous system, the mTOR pathway regulates fundamental biological processes associated with neural development and neurodegeneration. Intriguingly, genes that constitute the mTOR pathway have been found to be germline and somatic mutation from patients with various epileptic disorders. Hyperactivation of the mTOR pathway due to said mutations has garnered increasing attention as culprits of these conditions : somatic mutations, in particular, in epileptic foci have recently been identified as a major genetic cause of intractable focal epilepsy, such as focal cortical dysplasia. Meanwhile, epilepsy models with aberrant activation of the mTOR pathway have helped elucidate the role of the mTOR pathway in epileptogenesis, and evidence from epilepsy models of human mutations recapitulating the features of epileptic patients has indicated that mTOR inhibitors may be of use in treating epilepsy associated with mutations in mTOR pathway genes. Here, we review recent advances in the molecular and genetic understanding of mTOR signaling in epileptic disorders. In particular, we focus on the development of and limitations to therapies targeting the mTOR pathway to treat epileptic seizures. We also discuss future perspectives on mTOR inhibition therapies and special diagnostic methods for intractable epilepsies caused by brain somatic mutations.
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Affiliation(s)
- Jang Keun Kim
- Biomedical Science and Engineering Interdisciplinary Program, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Korea
| | - Jeong Ho Lee
- Biomedical Science and Engineering Interdisciplinary Program, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Korea.,Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Korea
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37
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Mühlebner A, Bongaarts A, Sarnat HB, Scholl T, Aronica E. New insights into a spectrum of developmental malformations related to mTOR dysregulations: challenges and perspectives. J Anat 2019; 235:521-542. [PMID: 30901081 DOI: 10.1111/joa.12956] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/15/2019] [Indexed: 12/20/2022] Open
Abstract
In recent years the role of the mammalian target of rapamycin (mTOR) pathway has emerged as crucial for normal cortical development. Therefore, it is not surprising that aberrant activation of mTOR is associated with developmental malformations and epileptogenesis. A broad spectrum of malformations of cortical development, such as focal cortical dysplasia (FCD) and tuberous sclerosis complex (TSC), have been linked to either germline or somatic mutations in mTOR pathway-related genes, commonly summarised under the umbrella term 'mTORopathies'. However, there are still a number of unanswered questions regarding the involvement of mTOR in the pathophysiology of these abnormalities. Therefore, a monogenetic disease, such as TSC, can be more easily applied as a model to study the mechanisms of epileptogenesis and identify potential new targets of therapy. Developmental neuropathology and genetics demonstrate that FCD IIb and hemimegalencephaly are the same diseases. Constitutive activation of mTOR signalling represents a shared pathogenic mechanism in a group of developmental malformations that have histopathological and clinical features in common, such as epilepsy, autism and other comorbidities. We seek to understand the effect of mTOR dysregulation in a developing cortex with the propensity to generate seizures as well as the aftermath of the surrounding environment, including the white matter.
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Affiliation(s)
- A Mühlebner
- Department of Neuropathology, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
| | - A Bongaarts
- Department of Neuropathology, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
| | - H B Sarnat
- Departments of Paediatrics, Pathology (Neuropathology) and Clinical Neurosciences, University of Calgary Cumming School of Medicine and Alberta Children's Hospital Research Institute (Owerko Centre), Calgary, AB, Canada
| | - T Scholl
- Department of Paediatric and Adolescent Medicine, Medical University of Vienna, Vienna, Austria
| | - E Aronica
- Department of Neuropathology, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands.,Stichting Epilepsie Instellingen Nederland (SEIN), Amsterdam, The Netherlands
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38
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Arafa SR, LaSarge CL, Pun RYK, Khademi S, Danzer SC. Self-reinforcing effects of mTOR hyperactive neurons on dendritic growth. Exp Neurol 2019; 311:125-134. [PMID: 30268766 PMCID: PMC6263818 DOI: 10.1016/j.expneurol.2018.09.019] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Revised: 09/17/2018] [Accepted: 09/27/2018] [Indexed: 10/28/2022]
Abstract
Loss of the mTOR pathway negative regulator PTEN from hippocampal dentate granule cells leads to neuronal hypertrophy, increased dendritic branching and aberrant basal dendrite formation in animal models. Similar changes are evident in humans with mTOR pathway mutations. These genetic conditions are associated with autism, cognitive dysfunction and epilepsy. Interestingly, humans with mTOR pathway mutations often present with mosaic disruptions of gene function, producing lesions that range from focal cortical dysplasia to hemimegalanecephaly. Whether mTOR-mediated neuronal dysmorphogenesis is impacted by the number of affected cells, however, is not known. mTOR mutations can produce secondary comorbidities, including brain hypertrophy and seizures, which could exacerbate dysmorphogenesis among mutant cells. To determine whether the percentage or "load" of PTEN knockout granule cells impacts the morphological development of these same cells, we generated two groups of PTEN knockout mice. In the first, PTEN deletion rates were held constant, at about 5%, and knockout cell growth over time was assessed. Knockout cells exhibited significant dendritic growth between 7 and 18 weeks, demonstrating that aberrant dendritic growth continues even after the cells reach maturity. In the second group of mice, PTEN was deleted from 2 to 37% of granule cells to determine whether deletion rate was a factor in driving this continued growth. Multivariate analysis revealed that both age and knockout cell load contributed to knockout cell dendritic growth. Although the mechanism remains to be determined, these findings demonstrate that large numbers of mutant neurons can produce self-reinforcing effects on their own growth.
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Affiliation(s)
- Salwa R Arafa
- Department of Anesthesia, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, United States; Department of Drug Development, James L Winkle College of Pharmacy, University of Cincinnati, OH 45267, United States
| | - Candi L LaSarge
- Department of Anesthesia, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, United States
| | - Raymund Y K Pun
- Department of Anesthesia, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, United States
| | - Shadi Khademi
- Department of Anesthesia, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, United States
| | - Steve C Danzer
- Department of Anesthesia, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, United States; Departments of Anesthesia and Pediatrics, University of Cincinnati, Cincinnati, OH 45267, United States.
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Nelson K, Jackman C, Bell J, Shih CS, Payne K, Dlouhy S, Walsh L. Novel Homozygous Deletion in STRADA Gene Associated With Polyhydramnios, Megalencephaly, and Epilepsy in 2 Siblings: Implications for Diagnosis and Treatment. J Child Neurol 2018; 33:925-929. [PMID: 30311510 DOI: 10.1177/0883073818802724] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Mutations in the STE20-related kinase adaptor α ( STRADA) gene have been reported to cause an autosomal recessive neurodevelopmental disorder characterized by infantile-onset epilepsy, developmental delay, and craniofacial dysmorphisms. To date, there have been 17 reported individuals diagnosed with STRADA mutations, 16 of which are from a single Old Order Mennonite cohort and share a deletion of exons 9-13. The remaining individual is of consanguineous Indian descent and has a homozygous single-base pair duplication. We report a novel STRADA gene deletion of exons 7-9 in 2 sisters from nonconsanguineous parents, as well as an improvement in seizure control in 1 sibling following treatment with sirolimus, an m-Tor inhibitor of potential benefit to patients with this genetic mutation.
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Affiliation(s)
- Katherine Nelson
- 1 Department of Medical and Molecular Genetics, Indiana University Health, Indianapolis, IN, USA
| | - Christopher Jackman
- 2 Department of Neurology, Division of Child Neurology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Jennifer Bell
- 3 Department of Pediatric Oncology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Chie-Schin Shih
- 4 Department of Pediatrics, Division of Hematology/Oncology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Katelyn Payne
- 2 Department of Neurology, Division of Child Neurology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Stephen Dlouhy
- 5 Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Laurence Walsh
- 2 Department of Neurology, Division of Child Neurology, Indiana University School of Medicine, Indianapolis, IN, USA
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40
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Amberg R, Elad A, Rothamel D, Fienitz T, Szakacs G, Heilmann S, Witte F. Design of a migration assay for human gingival fibroblasts on biodegradable magnesium surfaces. Acta Biomater 2018; 79:158-67. [PMID: 30172066 DOI: 10.1016/j.actbio.2018.08.034] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Revised: 08/24/2018] [Accepted: 08/28/2018] [Indexed: 02/08/2023]
Abstract
A novel regenerative approach to Guided Bone Regeneration (GBR) in dental surgery is based on the development of biodegradable and volume stable barrier membranes made of metallic magnesium. Currently used volume stable barrier membranes are made of titanium-reinforced PTFE or titanium-reinforced collagen membranes, both, however, are accompanied by a high incidence of wound dehiscence resulting in membrane exposure, which leads to an increased infection risk. An exposed membrane could also occur directly after insertion due to insufficient soft tissue coverage of the membrane. In both cases, fast wound margin regeneration is required. As a first step of soft-tissue regeneration, gingival fibroblasts need to migrate over the barrier membrane and close the dehiscent wound. Based on this aim, this study investigated the migration behaviour of human gingival fibroblasts on a magnesium surface. Major experimental challenges such as formation of hydrogen bubbles due to initial magnesium corrosion and non-transparent material surfaces have been addressed to allow cell adhesion and to follow cell migration. The designed scratch-based cell migration assay involved vital fluorescent cell staining on a pre-corroded magnesium membrane to simulate invivo wound dehiscence. The assay has been used to compare cell migration on pre-corroded magnesium to titanium surfaces and tissue culture plastic as control substrates. First results of this assay showed that human gingival fibroblasts migrate slower on pre-corroded magnesium compared to plastic and titanium. However, the scratch was finally closed on all materials. Compared to titanium surfaces and tissue culture plastic, the surface roughness and the surface free energy (SFE) could not explain slower cell migration on magnesium surfaces. Immunohistological investigations of cellular structure revealed, that magnesium ions increased focal adhesion at concentration of additionally 75 mM MgCl2 in cell culture medium. The use of our designed cell migration assay has shown that ionic medium alterations due to magnesium corrosion has a higher impact on the cell migration rate than surface alterations. STATEMENT OF SIGNIFICANCE The design of a migration assay on non-transparent magnesium surfaces will add the option to study cell response to surface modifications, coatings and the corrosion process itself under life view conditions.
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41
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Kumar J, Solaiman A, Mahakkanukrauh P, Mohamed R, Das S. Sleep Related Epilepsy and Pharmacotherapy: An Insight. Front Pharmacol 2018; 9:1088. [PMID: 30319421 PMCID: PMC6171479 DOI: 10.3389/fphar.2018.01088] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Accepted: 09/07/2018] [Indexed: 01/26/2023] Open
Abstract
In the last several decades, sleep-related epilepsy has drawn considerable attention among epileptologists and neuroscientists in the interest of new paradigms of the disease etiology, pathogenesis and management. Sleep-related epilepsy is nocturnal seizures that manifest solely during the sleep state. Sleep comprises two distinct stages i.e., non-rapid eye movement (NREM) and rapid eye movement (REM) that alternate every 90 min with NREM preceding REM. Current findings indicate that the sleep-related epilepsy manifests predominantly during the synchronized stages of sleep; NREM over REM stage. Sleep related hypermotor epilepsy (SHE), benign partial epilepsy with centrotemporal spikes or benign rolandic epilepsy (BECTS), and Panayiotopoulos Syndrome (PS) are three of the most frequently implicated epilepsies occurring during the sleep state. Although some familial types are described, others are seemingly sporadic occurrences. In the present review, we aim to discuss the predominance of sleep-related epilepsy during NREM, established familial links to the pathogenesis of SHE, BECTS and PS, and highlight the present available pharmacotherapy options.
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Affiliation(s)
- Jaya Kumar
- Department of Physiology, Faculty of Medicine, Universiti Kebangsaan Malaysia Medical Centre, Kuala Lumpur, Malaysia
| | - Amro Solaiman
- Department of Anatomy, Universiti Kebangsaan Malaysia Medical Centre, Kuala Lumpur, Malaysia
| | - Pasuk Mahakkanukrauh
- Department of Anatomy, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
- Excellence Centre in Forensic Osteology Research Center, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - Rashidi Mohamed
- Department of Familty Medicine, Universiti Kebangsaan Malaysia Medical Centre, Kuala Lumpur, Malaysia
| | - Srijit Das
- Department of Anatomy, Universiti Kebangsaan Malaysia Medical Centre, Kuala Lumpur, Malaysia
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42
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Abstract
Nearly a third of patients with epilepsy have seizures refractory to current medical therapies. In the search for novel drug targets, the mTOR pathway has emerged as key in the regulation of neuronal function, growth and survival, and other cellular processes related to epileptogenesis. Hyperactivation of the mTOR pathway has been implicated in tuberous sclerosis complex and other 'mTORopathies', clinical syndromes associated with cortical developmental malformations and drug-resistant epilepsy. Recently published clinical trials of mTOR inhibitors in tuberous sclerosis complex have shown that these drugs are effective at decreasing seizure frequency. Future studies may establish whether mTOR inhibitors can provide effective treatment for patients with diverse genetic and acquired epilepsies, including preventative, disease-modifying therapies.
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Affiliation(s)
- Jennifer L Griffith
- Department of Neurology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Michael Wong
- Department of Neurology, Washington University School of Medicine, St. Louis, MO 63110, USA
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43
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Sundaram SM, Garg P. Asymmetric Golgi Repositioning: A Prerequisite for Appropriate Dendrite Formation in Adult-Born Neurons. J Neurosci 2018; 38:4843-5. [PMID: 29793931 DOI: 10.1523/JNEUROSCI.0416-18.2018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Revised: 04/13/2018] [Accepted: 04/24/2018] [Indexed: 11/21/2022] Open
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44
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Koubeissi M. Seizures in Tuberous Sclerosis: Mechanism-Based Interventions EXIST. Epilepsy Curr 2018; 18:39-41. [DOI: 10.5698/1535-7597.18.1.39] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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45
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Affiliation(s)
- Paolo Curatolo
- Child Neurology and Psychiatry Unit, Systems Medicine Department, Tor Vergata University Hospital, Rome, Italy
| | - Romina Moavero
- Child Neurology and Psychiatry Unit, Systems Medicine Department, Tor Vergata University Hospital, Rome, Italy
- Child Neurology Unit, Neuroscience and Neurorehabilitation Department, “Bambino Gesù” Children’s Hospital, IRCCS, Rome, Italy
| | - Jackelien van Scheppingen
- Department of (Neuro)Pathology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Eleonora Aronica
- Department of (Neuro)Pathology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
- Stichting Epilepsie Instellingen Nederland (SEIN), The Netherlands
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46
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Abstract
Malformations of cortical development represent a common cause of epileptic encephalopathies and drug-resistant epilepsy in children. As current treatments are often ineffective, new therapeutic targets are needed for epileptic encephalopathies associated with cortical malformations. The mechanistic/mammalian target of rapamycin (mTOR) pathway constitutes a signaling pathway that drives cellular and molecular mechanisms of epileptogenesis in a variety of focal cortical malformations. mTOR inhibitors prevent epilepsy and associated pathogenic mechanisms of epileptogenesis in mouse models of tuberous sclerosis complex and are currently in clinical trials for drug-resistant seizures in these patients. A recent explosion of genetic studies has linked mutations in various genes regulating the mTOR pathway to other cortical malformations, such as focal cortical dysplasia and hemimegalencephaly. Thus, mTOR inhibitors represent promising candidates as novel antiseizure and antiepileptogenic therapies for epilepsy associated with a spectrum of cortical malformations.
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Affiliation(s)
- Anna Jeong
- Department of Neurology and the Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, MO, USA
| | - Michael Wong
- Department of Neurology and the Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, MO, USA
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47
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Rao S, Kirschen GW, Szczurkowska J, Di Antonio A, Wang J, Ge S, Shelly M. Repositioning of Somatic Golgi Apparatus Is Essential for the Dendritic Establishment of Adult-Born Hippocampal Neurons. J Neurosci 2018; 38:631-47. [PMID: 29217690 DOI: 10.1523/JNEUROSCI.1217-17.2017] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Revised: 10/02/2017] [Accepted: 10/29/2017] [Indexed: 01/22/2023] Open
Abstract
New dentate granule cells (DGCs) are continuously generated, and integrate into the preexisting hippocampal network in the adult brain. How an adult-born neuron with initially simple spindle-like morphology develops into a DGC, consisting of a single apical dendrite with further branches, remains largely unknown. Here, using retroviruses to birth date and manipulate newborn neurons, we examined initial dendritic formation and possible underlying mechanisms. We found that GFP-expressing newborn cells began to establish a DGC-like morphology at ∼7 d after birth, with a primary dendrite pointing to the molecular layer, but at this stage, with several neurites in the neurogenic zone. Interestingly, the Golgi apparatus, an essential organelle for neurite growth and maintenance, was dynamically repositioning in the soma of newborn cells during this initial integration stage. Two weeks after birth, by which time most neurites in the neurogenic zone were eliminated, a compact Golgi apparatus was positioned exclusively at the base of the primary dendrite. We analyzed the presence of Golgi-associated genes using single-cell transcriptomes of newborn DGCs, and among Golgi-related genes, found the presence of STK25 and STRAD, regulators of embryonic neuronal development. When we knocked down either of these two proteins, we found Golgi mislocalization and extensive aberrant dendrite formation. Furthermore, overexpression of a mutated form of STRAD, underlying the disorder polyhydramnios, megalencephaly, and symptomatic epilepsy, characterized by abnormal brain development and intractable epilepsy, caused similar defects in Golgi localization and dendrite formation in adult-born neurons. Together, our findings reveal a role for Golgi repositioning in regulating the initial integration of adult-born DGCs.SIGNIFICANCE STATEMENT Since the discovery of the continuous generation of new neurons in the adult hippocampus, extensive effort was directed toward understanding the functional contribution of these newborn neurons to the existing hippocampal circuit and associated behaviors, while the molecular mechanisms controlling their early morphological integration are less well understood. Dentate granule cells (DGCs) have a single, complex, apical dendrite. The events leading adult-born DGCs' to transition from simple spindle-like morphology to mature dendrite morphology are largely unknown. We studied establishment of newborn DGCs dendritic pattern and found it was mediated by a signaling pathway regulating precise localization of the Golgi apparatus. Furthermore, this Golgi-associated mechanism for dendrite establishment might be impaired in a human genetic epilepsy syndrome, polyhydramnios, megalencephaly, and symptomatic epilepsy.
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Ryskalin L, Lazzeri G, Flaibani M, Biagioni F, Gambardella S, Frati A, Fornai F. mTOR-Dependent Cell Proliferation in the Brain. Biomed Res Int 2017; 2017:7082696. [PMID: 29259984 DOI: 10.1155/2017/7082696] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Accepted: 10/22/2017] [Indexed: 02/08/2023]
Abstract
The mammalian Target of Rapamycin (mTOR) is a molecular complex equipped with kinase activity which controls cell viability being key in the PI3K/PTEN/Akt pathway. mTOR acts by integrating a number of environmental stimuli to regulate cell growth, proliferation, autophagy, and protein synthesis. These effects are based on the modulation of different metabolic pathways. Upregulation of mTOR associates with various pathological conditions, such as obesity, neurodegeneration, and brain tumors. This is the case of high-grade gliomas with a high propensity to proliferation and tissue invasion. Glioblastoma Multiforme (GBM) is a WHO grade IV malignant, aggressive, and lethal glioma. To date, a few treatments are available although the outcome of GBM patients remains poor. Experimental and pathological findings suggest that mTOR upregulation plays a major role in determining an aggressive phenotype, thus determining relapse and chemoresistance. Among several activities, mTOR-induced autophagy suppression is key in GBM malignancy. In this article, we discuss recent evidence about mTOR signaling and its role in normal brain development and pathological conditions, with a special emphasis on its role in GBM.
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Evers C, Staufner C, Granzow M, Paramasivam N, Hinderhofer K, Kaufmann L, Fischer C, Thiel C, Opladen T, Kotzaeridou U, Wiemann S, Schlesner M, Eils R, Kölker S, Bartram CR, Hoffmann GF, Moog U. Impact of clinical exomes in neurodevelopmental and neurometabolic disorders. Mol Genet Metab 2017; 121:297-307. [PMID: 28688840 DOI: 10.1016/j.ymgme.2017.06.014] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Revised: 06/29/2017] [Accepted: 06/29/2017] [Indexed: 01/06/2023]
Abstract
Whole exome sequencing (WES) is well established in research and is now being introduced into clinically indicated diagnostics (so-called clinical exomes). We evaluated the diagnostic yield and clinical implications of WES in 72 patients from 60 families with undiagnosed neurodevelopmental disorders (NDD), neurometabolic disorders, and dystonias. Pathogenic or likely pathogenic variants leading to a molecular diagnosis could be identified in 21 of the 60 families (overall 35%, in 36% of patients with NDD, in 43% of patients with neurometabolic disorders, in 25% of patients with dystonias). In one family two coexisting autosomal recessive diseases caused by homozygous pathogenic variants in two different genes were diagnosed. In another family, a homozygous frameshift variant in STRADA was found to cause a severe NDD with early onset epilepsy, brain anomalies, hypotonia, heart defect, nephrocalcinosis, macrocephaly and distinctive facies so far designated as PMSE (polyhydramnios, megalencephaly, symptomatic epilepsy) syndrome. In 7 of the 21 families with a molecular diagnosis the pathogenic variants were only identified by clinical follow-up, manual reevaluation of the literature, a change of filter setting, and/or reconsideration of inheritance pattern. Most importantly, clinical implications included management changes in 8 cases and impact on family planning in 20 families with a molecular diagnosis. This study shows that reevaluation and follow-up can improve the diagnostic rate and that WES results have important implications on medical management and family planning. Furthermore, we could confirm STRADA as a gene associated with syndromic ID but find it questionable if the current designation as PMSE depicts the most important clinical features.
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Affiliation(s)
- Christina Evers
- Institute of Human Genetics, University of Heidelberg, Im Neuenheimer Feld 366, 69120 Heidelberg, Germany.
| | - Christian Staufner
- Department of General Pediatrics, Division of Neuropediatrics and Metabolic Medicine, University Hospital Heidelberg, Im Neuenheimer Feld 430, 69120 Heidelberg, Germany
| | - Martin Granzow
- Institute of Human Genetics, University of Heidelberg, Im Neuenheimer Feld 366, 69120 Heidelberg, Germany
| | - Nagarajan Paramasivam
- Medical Faculty Heidelberg, Heidelberg University, 69120 Heidelberg, Germany; Division of Theoretical Bioinformatics, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Katrin Hinderhofer
- Institute of Human Genetics, University of Heidelberg, Im Neuenheimer Feld 366, 69120 Heidelberg, Germany
| | - Lilian Kaufmann
- Institute of Human Genetics, University of Heidelberg, Im Neuenheimer Feld 366, 69120 Heidelberg, Germany
| | - Christine Fischer
- Institute of Human Genetics, University of Heidelberg, Im Neuenheimer Feld 366, 69120 Heidelberg, Germany
| | - Christian Thiel
- Department of General Pediatrics, Division of Neuropediatrics and Metabolic Medicine, University Hospital Heidelberg, Im Neuenheimer Feld 430, 69120 Heidelberg, Germany
| | - Thomas Opladen
- Department of General Pediatrics, Division of Neuropediatrics and Metabolic Medicine, University Hospital Heidelberg, Im Neuenheimer Feld 430, 69120 Heidelberg, Germany
| | - Urania Kotzaeridou
- Department of General Pediatrics, Division of Neuropediatrics and Metabolic Medicine, University Hospital Heidelberg, Im Neuenheimer Feld 430, 69120 Heidelberg, Germany
| | - Stefan Wiemann
- Genomics & Proteomics Core Facility, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 580, 69120 Heidelberg, Germany
| | - Matthias Schlesner
- Division of Theoretical Bioinformatics, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Roland Eils
- Division of Theoretical Bioinformatics, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany; Department for Bioinformatics and Functional Genomics, Institute for Pharmacy and Molecular Biotechnology (IPMB) and BioQuant, Heidelberg University, 69120 Heidelberg, Germany
| | - Stefan Kölker
- Department of General Pediatrics, Division of Neuropediatrics and Metabolic Medicine, University Hospital Heidelberg, Im Neuenheimer Feld 430, 69120 Heidelberg, Germany
| | - Claus R Bartram
- Institute of Human Genetics, University of Heidelberg, Im Neuenheimer Feld 366, 69120 Heidelberg, Germany
| | - Georg F Hoffmann
- Department of General Pediatrics, Division of Neuropediatrics and Metabolic Medicine, University Hospital Heidelberg, Im Neuenheimer Feld 430, 69120 Heidelberg, Germany
| | - Ute Moog
- Institute of Human Genetics, University of Heidelberg, Im Neuenheimer Feld 366, 69120 Heidelberg, Germany
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Pavone P, Praticò AD, Rizzo R, Corsello G, Ruggieri M, Parano E, Falsaperla R. A clinical review on megalencephaly: A large brain as a possible sign of cerebral impairment. Medicine (Baltimore) 2017; 96:e6814. [PMID: 28658095 PMCID: PMC5500017 DOI: 10.1097/md.0000000000006814] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Revised: 02/23/2017] [Accepted: 02/27/2017] [Indexed: 11/26/2022] Open
Abstract
Megalencephaly and macrocephaly present with a head circumference measurement 2 standard deviations above the age-related mean. However, even if pathologic events resulting in both megalencephaly and macrocephaly may coexist, a distinction between these two entities is appropriate, as they represent clinical expression of different disorders with a different approach in clinical work-up, overall prognosis, and treatment. Megalencephaly defines an increased growth of cerebral structures related to dysfunctional anomalies during the various steps of brain development in the neuronal proliferation and/or migration phases or as a consequence of postnatal abnormal events. The disorders associated with megalencephaly are classically defined into 3 groups: idiopathic or benign, metabolic, and anatomic. In this article, we seek to underline the clinical aspect of megalencephaly, emphasizing the main disorders that manifest with this anomaly in an attempt to properly categorize these disorders within the megalencephaly group.
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Affiliation(s)
- Piero Pavone
- University-Hospital “Policlinico-Vittorio Emanuele”
| | - Andrea Domenico Praticò
- Department of Clinical and Experimental Medicine, Section of Pediatrics and Child Neuropsychiatry
- Maurice Wohl Clinical Neuroscience Institute, King's College London, London, UK
| | - Renata Rizzo
- Department of Clinical and Experimental Medicine, Section of Pediatrics and Child Neuropsychiatry
| | - Giovanni Corsello
- Department of Maternal and Child Health, University of Palermo, Palermo
| | - Martino Ruggieri
- Department of Clinical and Experimental Medicine, Section of Pediatrics and Child Neuropsychiatry
| | - Enrico Parano
- National Research Council, Section of Catania, Catania, Italy
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