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Ribierre T, Bacq A, Donneger F, Doladilhe M, Maletic M, Roussel D, Le Roux I, Chassoux F, Devaux B, Adle-Biassette H, Ferrand-Sorbets S, Dorfmüller G, Chipaux M, Baldassari S, Poncer JC, Baulac S. Targeting pathological cells with senolytic drugs reduces seizures in neurodevelopmental mTOR-related epilepsy. Nat Neurosci 2024; 27:1125-1136. [PMID: 38710875 PMCID: PMC11156583 DOI: 10.1038/s41593-024-01634-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Accepted: 03/28/2024] [Indexed: 05/08/2024]
Abstract
Cortical malformations such as focal cortical dysplasia type II (FCDII) are associated with pediatric drug-resistant epilepsy that necessitates neurosurgery. FCDII results from somatic mosaicism due to post-zygotic mutations in genes of the PI3K-AKT-mTOR pathway, which produce a subset of dysmorphic cells clustered within healthy brain tissue. Here we show a correlation between epileptiform activity in acute cortical slices obtained from human surgical FCDII brain tissues and the density of dysmorphic neurons. We uncovered multiple signatures of cellular senescence in these pathological cells, including p53/p16 expression, SASP expression and senescence-associated β-galactosidase activity. We also show that administration of senolytic drugs (dasatinib/quercetin) decreases the load of senescent cells and reduces seizure frequency in an MtorS2215F FCDII preclinical mouse model, providing proof of concept that senotherapy may be a useful approach to control seizures. These findings pave the way for therapeutic strategies selectively targeting mutated senescent cells in FCDII brain tissue.
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Affiliation(s)
- Théo Ribierre
- Sorbonne Université, Institut du Cerveau - Paris Brain Institute - ICM, Inserm, CNRS, AP-HP, Hôpital de la Pitié Salpêtrière, Paris, France
- Department of Basic Neurosciences, University of Geneva, Geneva, Switzerland
- NeuroNA Human Cellular Neuroscience Platform, Fondation Campus Biotech Geneva, Geneva, Switzerland
| | - Alexandre Bacq
- Sorbonne Université, Institut du Cerveau - Paris Brain Institute - ICM, Inserm, CNRS, AP-HP, Hôpital de la Pitié Salpêtrière, Paris, France
| | - Florian Donneger
- Institut du Fer à Moulin, INSERM, Sorbonne Université, UMR-S 1270, Paris, France
| | - Marion Doladilhe
- Sorbonne Université, Institut du Cerveau - Paris Brain Institute - ICM, Inserm, CNRS, AP-HP, Hôpital de la Pitié Salpêtrière, Paris, France
| | - Marina Maletic
- Sorbonne Université, Institut du Cerveau - Paris Brain Institute - ICM, Inserm, CNRS, AP-HP, Hôpital de la Pitié Salpêtrière, Paris, France
| | - Delphine Roussel
- Sorbonne Université, Institut du Cerveau - Paris Brain Institute - ICM, Inserm, CNRS, AP-HP, Hôpital de la Pitié Salpêtrière, Paris, France
| | - Isabelle Le Roux
- Sorbonne Université, Institut du Cerveau - Paris Brain Institute - ICM, Inserm, CNRS, AP-HP, Hôpital de la Pitié Salpêtrière, Paris, France
| | - Francine Chassoux
- Service de Neurochirurgie, AP-HP, Hôpital Lariboisière, Paris, France
- GHU Paris, Psychiatrie et Neurosciences, Paris, France
| | - Bertrand Devaux
- Service de Neurochirurgie, AP-HP, Hôpital Lariboisière, Paris, France
- GHU Paris, Psychiatrie et Neurosciences, Paris, France
| | - Homa Adle-Biassette
- Université de Paris Cité, Service d'Anatomie Pathologique, AP-HP, Hôpital Lariboisière, DMU DREAM, UMR 1141, INSERM, Paris, France
| | | | - Georg Dorfmüller
- Department of Pediatric Neurosurgery, Rothschild Foundation Hospital, Paris, France
| | - Mathilde Chipaux
- Department of Pediatric Neurosurgery, Rothschild Foundation Hospital, Paris, France
| | - Sara Baldassari
- Sorbonne Université, Institut du Cerveau - Paris Brain Institute - ICM, Inserm, CNRS, AP-HP, Hôpital de la Pitié Salpêtrière, Paris, France
| | | | - Stéphanie Baulac
- Sorbonne Université, Institut du Cerveau - Paris Brain Institute - ICM, Inserm, CNRS, AP-HP, Hôpital de la Pitié Salpêtrière, Paris, France.
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Alghamdi M, Chen JF, Jungbluth A, Koutzaki S, Palmer MB, Al-Ahmadie HA, Fine SW, Gopalan A, Sarungbam J, Sirintrapun SJ, Tickoo SK, Reuter VE, Chen YB. L1 Cell Adhesion Molecule (L1CAM) Expression and Molecular Alterations Distinguish Low-Grade Oncocytic Tumor From Eosinophilic Chromophobe Renal Cell Carcinoma. Mod Pathol 2024; 37:100467. [PMID: 38460672 PMCID: PMC11102321 DOI: 10.1016/j.modpat.2024.100467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Revised: 02/06/2024] [Accepted: 03/01/2024] [Indexed: 03/11/2024]
Abstract
Renal low-grade oncocytic tumor (LOT) is a recently recognized renal cell neoplasm designated within the "other oncocytic tumors" category in the 2022 World Health Organization classification system. Although the clinicopathologic, immunohistochemical, and molecular features reported for LOT have been largely consistent, the data are relatively limited. The morphologic overlap between LOT and other low-grade oncocytic neoplasms, particularly eosinophilic chromophobe renal cell carcinoma (E-chRCC), remains a controversial area in renal tumor classification. To address this uncertainty, we characterized and compared large cohorts of LOT (n = 67) and E-chRCC (n = 69) and revealed notable differences between the 2 entities. Clinically, LOT predominantly affected women, whereas E-chRCC showed a male predilection. Histologically, although almost all LOTs were dominated by a small-nested pattern, E-chRCC mainly showed solid and tubular architectures. Molecular analysis revealed that 87% of LOT cases harbored mutations in the tuberous sclerosis complex (TSC)-mTOR complex 1 (mTORC1) pathway, most frequently in MTOR and RHEB genes; a subset of LOT cases had chromosomal 7 and 19q gains. In contrast, E-chRCC lacked mTORC1 mutations, and 60% of cases displayed chromosomal losses characteristic of chRCC. We also explored the cell of origin for LOT and identified L1 cell adhesion molecule (L1CAM), a collecting duct and connecting tubule principal cell marker, as a highly sensitive and specific ancillary test for differentiating LOT from E-chRCC. This distinctive L1CAM immunohistochemical labeling suggests the principal cells as the cell of origin for LOT, unlike the intercalated cell origin of E-chRCC and oncocytoma. The ultrastructural analysis of LOT showed normal-appearing mitochondria and intracytoplasmic lumina with microvilli, different from what has been described for chRCC. Our study further supports LOT as a unique entity with a benign clinical course. Based on the likely cell of origin and its clinicopathologic characteristics, we propose that changing the nomenclature of LOT to "Oncocytic Principal Cell Adenoma of the Kidney" may be a better way to define and describe this entity.
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Affiliation(s)
- Mohammed Alghamdi
- Department of Pathology and Laboratory Medicine, Memorial Sloan Kettering Cancer Center, New York, New York; Department of Pathology and Laboratory Medicine, Hospital of the University of Pennsylvania, University of Pennsylvania, Perelman School of Medicine, Philadelphia, Pennsylvania
| | - Jie-Fu Chen
- Department of Pathology and Laboratory Medicine, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Achim Jungbluth
- Department of Pathology and Laboratory Medicine, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Sirma Koutzaki
- Department of Pathology and Laboratory Medicine, Hospital of the University of Pennsylvania, University of Pennsylvania, Perelman School of Medicine, Philadelphia, Pennsylvania
| | - Matthew B Palmer
- Department of Pathology and Laboratory Medicine, Hospital of the University of Pennsylvania, University of Pennsylvania, Perelman School of Medicine, Philadelphia, Pennsylvania
| | - Hikmat A Al-Ahmadie
- Department of Pathology and Laboratory Medicine, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Samson W Fine
- Department of Pathology and Laboratory Medicine, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Anuradha Gopalan
- Department of Pathology and Laboratory Medicine, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Judy Sarungbam
- Department of Pathology and Laboratory Medicine, Memorial Sloan Kettering Cancer Center, New York, New York
| | - S Joseph Sirintrapun
- Department of Pathology and Laboratory Medicine, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Satish K Tickoo
- Department of Pathology and Laboratory Medicine, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Victor E Reuter
- Department of Pathology and Laboratory Medicine, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Ying-Bei Chen
- Department of Pathology and Laboratory Medicine, Memorial Sloan Kettering Cancer Center, New York, New York.
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Coleman M, Pinares-Garcia P, Stephenson SE, Lee WS, Kooshavar D, Mclean CA, Howell KB, Leventer RJ, Reid CA, Lockhart PJ. Ectopic HCN4 Provides a Target Biomarker for the Genetic Spectrum of mTORopathies. Neurol Genet 2024; 10:e200135. [PMID: 38496361 PMCID: PMC10940058 DOI: 10.1212/nxg.0000000000200135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Accepted: 02/05/2024] [Indexed: 03/19/2024]
Abstract
Background and Objectives Pathogenic variants in PI3K-AKT-mTOR pathway and GATOR1 complex genes resulting in hyperactivation of mechanistic target of rapamycin (mTOR) complex 1 are a major cause of drug-resistant epilepsy and focal cortical malformations (FCM). Resective neurosurgery is often required to achieve seizure control in patients with mTORopathies due to lack of effectiveness of nonsurgical therapies, including antiseizure medication and mTOR inhibitors. Elevated hyperpolarization-activated cyclic nucleotide-gated potassium channel isoform 4 (HCN4) has been proposed as a key marker in some mTOR-related brain malformations. This study aimed to investigate HCN4 as a biomarker in the brain across the genetic spectrum of mTORopathies in humans. Methods Our study investigated the relative steady-state levels and cellular localization of HCN4 in resected human brain tissue from 18 individuals with mTORopathies (3 individuals with tuberous sclerosis complex (TSC) due to TSC2 variants, 5 individuals with focal cortical dysplasia type IIA (FCD IIA) due to genetic variants in MTOR, AKT3, and PIK3CA, and 10 individuals with FCD IIB due to variants in TSC1, MTOR, RHEB, DEPDC5, or NPRL3). Results Elevated HCN4 was observed to be highly restricted to abnormal cell types (dysmorphic neurons and balloon cells) in brain tissue from all mTORopathy tissues (p < 0.0001) compared with those in controls, regardless of genetic cause or variant allele frequency. Elevated HCN4 was not observed in controls or individuals with non-mTOR-related focal epilepsy due to pathogenic variants in ATP1A3, SLC35A2, or FGFR1. Discussion HCN4 provides a biomarker for the genetic spectrum of mTORopathies and may present a potential therapeutic target for seizure control in mTOR-related epilepsy.
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Affiliation(s)
- Matthew Coleman
- From the Murdoch Children's Research Institute (M.C., S.E.S., W.S.L., D.K., K.B.H., R.J.L., P.J.L.); Department of Paediatrics (M.C., S.E.S., D.K., K.B.H., R.J.L., P.J.L.), University of Melbourne; The Florey Institute of Neuroscience and Mental Health (P.P.-G., C.A.R.), Parkville; Alfred Hospital (C.A.M.), Prahran; Department of Neurology (K.B.H., R.J.L.), The Royal Children's Hospital, Parkville; and Epilepsy Research Centre (C.A.R.), Department of Medicine, University of Melbourne, Austin Health, Heidelberg, Victory, Australia
| | - Paulo Pinares-Garcia
- From the Murdoch Children's Research Institute (M.C., S.E.S., W.S.L., D.K., K.B.H., R.J.L., P.J.L.); Department of Paediatrics (M.C., S.E.S., D.K., K.B.H., R.J.L., P.J.L.), University of Melbourne; The Florey Institute of Neuroscience and Mental Health (P.P.-G., C.A.R.), Parkville; Alfred Hospital (C.A.M.), Prahran; Department of Neurology (K.B.H., R.J.L.), The Royal Children's Hospital, Parkville; and Epilepsy Research Centre (C.A.R.), Department of Medicine, University of Melbourne, Austin Health, Heidelberg, Victory, Australia
| | - Sarah E Stephenson
- From the Murdoch Children's Research Institute (M.C., S.E.S., W.S.L., D.K., K.B.H., R.J.L., P.J.L.); Department of Paediatrics (M.C., S.E.S., D.K., K.B.H., R.J.L., P.J.L.), University of Melbourne; The Florey Institute of Neuroscience and Mental Health (P.P.-G., C.A.R.), Parkville; Alfred Hospital (C.A.M.), Prahran; Department of Neurology (K.B.H., R.J.L.), The Royal Children's Hospital, Parkville; and Epilepsy Research Centre (C.A.R.), Department of Medicine, University of Melbourne, Austin Health, Heidelberg, Victory, Australia
| | - Wei Shern Lee
- From the Murdoch Children's Research Institute (M.C., S.E.S., W.S.L., D.K., K.B.H., R.J.L., P.J.L.); Department of Paediatrics (M.C., S.E.S., D.K., K.B.H., R.J.L., P.J.L.), University of Melbourne; The Florey Institute of Neuroscience and Mental Health (P.P.-G., C.A.R.), Parkville; Alfred Hospital (C.A.M.), Prahran; Department of Neurology (K.B.H., R.J.L.), The Royal Children's Hospital, Parkville; and Epilepsy Research Centre (C.A.R.), Department of Medicine, University of Melbourne, Austin Health, Heidelberg, Victory, Australia
| | - Daniz Kooshavar
- From the Murdoch Children's Research Institute (M.C., S.E.S., W.S.L., D.K., K.B.H., R.J.L., P.J.L.); Department of Paediatrics (M.C., S.E.S., D.K., K.B.H., R.J.L., P.J.L.), University of Melbourne; The Florey Institute of Neuroscience and Mental Health (P.P.-G., C.A.R.), Parkville; Alfred Hospital (C.A.M.), Prahran; Department of Neurology (K.B.H., R.J.L.), The Royal Children's Hospital, Parkville; and Epilepsy Research Centre (C.A.R.), Department of Medicine, University of Melbourne, Austin Health, Heidelberg, Victory, Australia
| | - Catriona A Mclean
- From the Murdoch Children's Research Institute (M.C., S.E.S., W.S.L., D.K., K.B.H., R.J.L., P.J.L.); Department of Paediatrics (M.C., S.E.S., D.K., K.B.H., R.J.L., P.J.L.), University of Melbourne; The Florey Institute of Neuroscience and Mental Health (P.P.-G., C.A.R.), Parkville; Alfred Hospital (C.A.M.), Prahran; Department of Neurology (K.B.H., R.J.L.), The Royal Children's Hospital, Parkville; and Epilepsy Research Centre (C.A.R.), Department of Medicine, University of Melbourne, Austin Health, Heidelberg, Victory, Australia
| | - Katherine B Howell
- From the Murdoch Children's Research Institute (M.C., S.E.S., W.S.L., D.K., K.B.H., R.J.L., P.J.L.); Department of Paediatrics (M.C., S.E.S., D.K., K.B.H., R.J.L., P.J.L.), University of Melbourne; The Florey Institute of Neuroscience and Mental Health (P.P.-G., C.A.R.), Parkville; Alfred Hospital (C.A.M.), Prahran; Department of Neurology (K.B.H., R.J.L.), The Royal Children's Hospital, Parkville; and Epilepsy Research Centre (C.A.R.), Department of Medicine, University of Melbourne, Austin Health, Heidelberg, Victory, Australia
| | - Richard J Leventer
- From the Murdoch Children's Research Institute (M.C., S.E.S., W.S.L., D.K., K.B.H., R.J.L., P.J.L.); Department of Paediatrics (M.C., S.E.S., D.K., K.B.H., R.J.L., P.J.L.), University of Melbourne; The Florey Institute of Neuroscience and Mental Health (P.P.-G., C.A.R.), Parkville; Alfred Hospital (C.A.M.), Prahran; Department of Neurology (K.B.H., R.J.L.), The Royal Children's Hospital, Parkville; and Epilepsy Research Centre (C.A.R.), Department of Medicine, University of Melbourne, Austin Health, Heidelberg, Victory, Australia
| | - Christopher A Reid
- From the Murdoch Children's Research Institute (M.C., S.E.S., W.S.L., D.K., K.B.H., R.J.L., P.J.L.); Department of Paediatrics (M.C., S.E.S., D.K., K.B.H., R.J.L., P.J.L.), University of Melbourne; The Florey Institute of Neuroscience and Mental Health (P.P.-G., C.A.R.), Parkville; Alfred Hospital (C.A.M.), Prahran; Department of Neurology (K.B.H., R.J.L.), The Royal Children's Hospital, Parkville; and Epilepsy Research Centre (C.A.R.), Department of Medicine, University of Melbourne, Austin Health, Heidelberg, Victory, Australia
| | - Paul J Lockhart
- From the Murdoch Children's Research Institute (M.C., S.E.S., W.S.L., D.K., K.B.H., R.J.L., P.J.L.); Department of Paediatrics (M.C., S.E.S., D.K., K.B.H., R.J.L., P.J.L.), University of Melbourne; The Florey Institute of Neuroscience and Mental Health (P.P.-G., C.A.R.), Parkville; Alfred Hospital (C.A.M.), Prahran; Department of Neurology (K.B.H., R.J.L.), The Royal Children's Hospital, Parkville; and Epilepsy Research Centre (C.A.R.), Department of Medicine, University of Melbourne, Austin Health, Heidelberg, Victory, Australia
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Nguyen LH, Xu Y, Nair M, Bordey A. The mTOR pathway genes MTOR, Rheb, Depdc5, Pten, and Tsc1 have convergent and divergent impacts on cortical neuron development and function. eLife 2024; 12:RP91010. [PMID: 38411613 PMCID: PMC10942629 DOI: 10.7554/elife.91010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/28/2024] Open
Abstract
Brain somatic mutations in various components of the mTOR complex 1 (mTORC1) pathway have emerged as major causes of focal malformations of cortical development and intractable epilepsy. While these distinct gene mutations converge on excessive mTORC1 signaling and lead to common clinical manifestations, it remains unclear whether they cause similar cellular and synaptic disruptions underlying cortical network hyperexcitability. Here, we show that in utero activation of the mTORC1 activator genes, Rheb or MTOR, or biallelic inactivation of the mTORC1 repressor genes, Depdc5, Tsc1, or Pten in the mouse medial prefrontal cortex leads to shared alterations in pyramidal neuron morphology, positioning, and membrane excitability but different changes in excitatory synaptic transmission. Our findings suggest that, despite converging on mTORC1 signaling, mutations in different mTORC1 pathway genes differentially impact cortical excitatory synaptic activity, which may confer gene-specific mechanisms of hyperexcitability and responses to therapeutic intervention.
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Affiliation(s)
- Lena H Nguyen
- Department of Neuroscience, School of Behavioral and Brain Sciences, University of Texas at DallasRichardsonUnited States
- Departments of Neurosurgery and Cellular & Molecular Physiology, Wu Tsai Institute, Yale University School of MedicineNew HavenUnited States
| | - Youfen Xu
- Departments of Neurosurgery and Cellular & Molecular Physiology, Wu Tsai Institute, Yale University School of MedicineNew HavenUnited States
| | - Maanasi Nair
- Departments of Neurosurgery and Cellular & Molecular Physiology, Wu Tsai Institute, Yale University School of MedicineNew HavenUnited States
| | - Angelique Bordey
- Departments of Neurosurgery and Cellular & Molecular Physiology, Wu Tsai Institute, Yale University School of MedicineNew HavenUnited States
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Nguyen LH, Xu Y, Nair M, Bordey A. The mTOR pathway genes mTOR, Rheb, Depdc5, Pten, and Tsc1 have convergent and divergent impacts on cortical neuron development and function. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.08.11.553034. [PMID: 37609221 PMCID: PMC10441381 DOI: 10.1101/2023.08.11.553034] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/24/2023]
Abstract
Brain somatic mutations in various components of the mTOR complex 1 (mTORC1) pathway have emerged as major causes of focal malformations of cortical development and intractable epilepsy. While these distinct gene mutations converge on excessive mTORC1 signaling and lead to common clinical manifestations, it remains unclear whether they cause similar cellular and synaptic disruptions underlying cortical network hyperexcitability. Here, we show that in utero activation of the mTORC1 activators, Rheb or mTOR, or biallelic inactivation of the mTORC1 repressors, Depdc5, Tsc1, or Pten in mouse medial prefrontal cortex leads to shared alterations in pyramidal neuron morphology, positioning, and membrane excitability but different changes in excitatory synaptic transmission. Our findings suggest that, despite converging on mTORC1 signaling, mutations in different mTORC1 pathway genes differentially impact cortical excitatory synaptic activity, which may confer gene-specific mechanisms of hyperexcitability and responses to therapeutic intervention.
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Affiliation(s)
- Lena H. Nguyen
- Department Neuroscience, School of Behavioral and Brain Sciences, University of Texas at Dallas, Richardson, TX 75080, USA
- Departments of Neurosurgery and Cellular & Molecular Physiology, Wu Tsai Institute, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Youfen Xu
- Departments of Neurosurgery and Cellular & Molecular Physiology, Wu Tsai Institute, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Maanasi Nair
- Departments of Neurosurgery and Cellular & Molecular Physiology, Wu Tsai Institute, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Angelique Bordey
- Departments of Neurosurgery and Cellular & Molecular Physiology, Wu Tsai Institute, Yale University School of Medicine, New Haven, CT 06510, USA
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Boßelmann CM, Leu C, Lal D. Technological and computational approaches to detect somatic mosaicism in epilepsy. Neurobiol Dis 2023:106208. [PMID: 37343892 DOI: 10.1016/j.nbd.2023.106208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2023] [Revised: 06/03/2023] [Accepted: 06/16/2023] [Indexed: 06/23/2023] Open
Abstract
Lesional epilepsy is a common and severe disease commonly associated with malformations of cortical development, including focal cortical dysplasia and hemimegalencephaly. Recent advances in sequencing and variant calling technologies have identified several genetic causes, including both short/single nucleotide and structural somatic variation. In this review, we aim to provide a comprehensive overview of the methodological advancements in this field while highlighting the unresolved technological and computational challenges that persist, including ultra-low variant allele fractions in bulk tissue, low availability of paired control samples, spatial variability of mutational burden within the lesion, and the issue of false-positive calls and validation procedures. Information from genetic testing in focal epilepsy may be integrated into clinical care to inform histopathological diagnosis, postoperative prognosis, and candidate precision therapies.
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Affiliation(s)
- Christian M Boßelmann
- Genomic Medicine Institute, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA; Epilepsy Center, Neurological Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Costin Leu
- Genomic Medicine Institute, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA; Department of Clinical and Experimental Epilepsy, Institute of Neurology, University College London, London, UK.
| | - Dennis Lal
- Genomic Medicine Institute, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA; Epilepsy Center, Neurological Institute, Cleveland Clinic, Cleveland, OH, USA; Stanley Center for Psychiatric Research, Broad Institute of Harvard and M.I.T., Cambridge, MA, USA; Cologne Center for Genomics (CCG), University of Cologne, Cologne, DE, USA
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7
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Checri R, Chipaux M, Ferrand-Sorbets S, Raffo E, Bulteau C, Rosenberg SD, Doladilhe M, Dorfmüller G, Adle-Biassette H, Baldassari S, Baulac S. Detection of brain somatic mutations in focal cortical dysplasia during epilepsy presurgical workup. Brain Commun 2023; 5:fcad174. [PMID: 37324239 PMCID: PMC10261848 DOI: 10.1093/braincomms/fcad174] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Revised: 04/01/2023] [Accepted: 05/31/2023] [Indexed: 06/17/2023] Open
Abstract
Brain-restricted somatic variants in genes of the mechanistic target of rapamycin signalling pathway cause focal epilepsies associated with focal cortical dysplasia type II. We hypothesized that somatic variants could be identified from trace tissue adherent to explanted stereoelectroencephalography electrodes used in the presurgical epilepsy workup to localize the epileptogenic zone. We investigated three paediatric patients with drug-resistant focal epilepsy subjected to neurosurgery. In the resected brain tissue, we identified low-level mosaic somatic mutations in AKT3 and DEPDC5 genes. We collected stereoelectroencephalography depth electrodes in the context of a second presurgical evaluation and identified 4/33 mutation-positive electrodes that were either located in the epileptogenic zone or at the border of the dysplasia. We provide the proof-of-concept that somatic mutations with low levels of mosaicism can be detected from individual stereoelectroencephalography electrodes and support a link between the mutation load and the epileptic activity. Our findings emphasize future opportunities for integrating genetic testing from stereoelectroencephalography electrodes into the presurgical evaluation of refractory epilepsy patients with focal cortical dysplasia type II to improve the patients' diagnostic journey and guide towards precision medicine.
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Affiliation(s)
| | | | - Sarah Ferrand-Sorbets
- Department of Pediatric Neurosurgery, Rothschild Foundation Hospital EpiCARE, 75019, Paris, France
| | - Emmanuel Raffo
- Department of Pediatric Neurosurgery, Rothschild Foundation Hospital EpiCARE, 75019, Paris, France
- Unité de recherche 3450 DevAH, Développement, Adaptation et Handicap, Campus Brabois-Santé, Université de Lorraine, 54505, Vandoeuvre-lès-Nancy, France
| | - Christine Bulteau
- Department of Pediatric Neurosurgery, Rothschild Foundation Hospital EpiCARE, 75019, Paris, France
- Université de Paris Cité, MC2Lab, Institut de Psychologie, F-92100 Boulogne-Billancourt, France
| | | | - Marion Doladilhe
- Sorbonne Université, Institut du Cerveau—Paris Brain Institute—ICM, Inserm, CNRS, Hôpital de la Pitié Salpêtrière, 75013, Paris, France
| | - Georg Dorfmüller
- Department of Pediatric Neurosurgery, Rothschild Foundation Hospital EpiCARE, 75019, Paris, France
| | - Homa Adle-Biassette
- Université de Paris Cité, service d’Anatomie Pathologique, APHP, Hôpital Lariboisière, DMU DREAM, UMR 1141, INSERM, 75010, Paris, France
| | | | - Stéphanie Baulac
- Correspondence to: Stéphanie Baulac Institut du Cerveau, 47 bd de l’hôpital, 75013, Paris, France E-mail:
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8
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Bizzotto S. The human brain through the lens of somatic mosaicism. Front Neurosci 2023; 17:1172469. [PMID: 37250426 PMCID: PMC10213359 DOI: 10.3389/fnins.2023.1172469] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Accepted: 04/25/2023] [Indexed: 05/31/2023] Open
Abstract
Every cell in the human brain possesses a unique genome that is the product of the accumulation of somatic mutations starting from the first postzygotic cell division and continuing throughout life. Somatic mosaicism in the human brain has been the focus of several recent efforts that took advantage of key technological innovations to start elucidating brain development, aging and disease directly in human tissue. On one side, somatic mutation occurring in progenitor cells has been used as a natural barcoding system to address cell phylogenies of clone formation and cell segregation in the brain lineage. On the other side, analyses of mutation rates and patterns in the genome of brain cells have revealed mechanisms of brain aging and disorder predisposition. In addition to the study of somatic mosaicism in the normal human brain, the contribution of somatic mutation has been investigated in both developmental neuropsychiatric and neurodegenerative disorders. This review starts with a methodological perspective on the study of somatic mosaicism to then cover the most recent findings in brain development and aging, and ends with the role of somatic mutations in brain disease. Thus, this review underlies what we have learned and what is still possible to discover by looking at somatic mosaicism in the brain genome.
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9
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Gerasimenko A, Baldassari S, Baulac S. mTOR pathway: Insights into an established pathway for brain mosaicism in epilepsy. Neurobiol Dis 2023; 182:106144. [PMID: 37149062 DOI: 10.1016/j.nbd.2023.106144] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2023] [Revised: 05/02/2023] [Accepted: 05/03/2023] [Indexed: 05/08/2023] Open
Abstract
The mechanistic target of rapamycin (mTOR) signaling pathway is an essential regulator of numerous cellular activities such as metabolism, growth, proliferation, and survival. The mTOR cascade recently emerged as a critical player in the pathogenesis of focal epilepsies and cortical malformations. The 'mTORopathies' comprise a spectrum of cortical malformations that range from whole brain (megalencephaly) and hemispheric (hemimegalencephaly) abnormalities to focal abnormalities, such as focal cortical dysplasia type II (FCDII), which manifest with drug-resistant epilepsies. The spectrum of cortical dysplasia results from somatic brain mutations in the mTOR pathway activators AKT3, MTOR, PIK3CA, and RHEB and from germline and somatic mutations in mTOR pathway repressors, DEPDC5, NPRL2, NPRL3, TSC1 and TSC2. The mTORopathies are characterized by excessive mTOR pathway activation, leading to a broad range of structural and functional impairments. Here, we provide a comprehensive literature review of somatic mTOR-activating mutations linked to epilepsy and cortical malformations in 292 patients and discuss the perspectives of targeted therapeutics for personalized medicine.
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Affiliation(s)
- Anna Gerasimenko
- Sorbonne Université, Institut du Cerveau - Paris Brain Institute - ICM, Inserm, CNRS, Hôpital de la Pitié Salpêtrière, 75013 Paris, France; APHP Sorbonne Université, GH Pitié Salpêtrière et Trousseau, Département de Génétique, Centre de référence "déficiences intellectuelles de causes rares", Paris, France
| | - Sara Baldassari
- Sorbonne Université, Institut du Cerveau - Paris Brain Institute - ICM, Inserm, CNRS, Hôpital de la Pitié Salpêtrière, 75013 Paris, France
| | - Stéphanie Baulac
- Sorbonne Université, Institut du Cerveau - Paris Brain Institute - ICM, Inserm, CNRS, Hôpital de la Pitié Salpêtrière, 75013 Paris, France.
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10
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Auvin S, Baulac S. mTOR-therapy and targeted treatment opportunities in mTOR-related epilepsies associated with cortical malformations. Rev Neurol (Paris) 2023; 179:337-344. [PMID: 36906459 DOI: 10.1016/j.neurol.2022.12.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Revised: 12/08/2022] [Accepted: 12/13/2022] [Indexed: 03/11/2023]
Abstract
Dysregulation of the mTOR pathway is now well documented in several neurodevelopmental disorders associated with epilepsy. Mutations of mTOR pathway genes are involved in tuberous sclerosis complex (TSC) as well as in a range of cortical malformations from hemimegalencephaly (HME) to type II focal cortical dysplasia (FCD II), leading to the concept of "mTORopathies" (mTOR pathway-related malformations). This suggests that mTOR inhibitors (notably rapamycin (sirolimus), and everolimus) could be used as antiseizure medication. In this review, we provide an overview of pharmacological treatments targeting the mTOR pathway for epilepsy based on lectures from the ILAE French Chapter meeting in October 2022 in Grenoble. There is strong preclinical evidence for the antiseizure effects of mTOR inhibitors in TSC and cortical malformation mouse models. There are also open studies on the antiseizure effects of mTOR inhibitors, as well as one phase III study showing the antiseizure effect of everolimus in TSC patients. Finally, we discuss to which extent mTOR inhibitors might have properties beyond the antiseizure effect on associated neuropsychiatric comorbidities. We also discuss a new way of treatment on the mTOR pathways.
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Affiliation(s)
- S Auvin
- Service de neurologie pédiatrique, EpiCARE ERN membre, Hôpital Robert Debré, AP-HP, Paris, France; Université Paris-Cité, Inserm NeuroDiderot, Paris, France; Institut Universitaire de France (IUF), Paris, France.
| | - S Baulac
- Sorbonne Université, Institut du Cerveau - Paris Brain Institute - ICM, Inserm, CNRS, Hôpital de la Pitié Salpêtrière, 75013 Paris, France
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11
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Chung C, Yang X, Bae T, Vong KI, Mittal S, Donkels C, Westley Phillips H, Li Z, Marsh APL, Breuss MW, Ball LL, Garcia CAB, George RD, Gu J, Xu M, Barrows C, James KN, Stanley V, Nidhiry AS, Khoury S, Howe G, Riley E, Xu X, Copeland B, Wang Y, Kim SH, Kang HC, Schulze-Bonhage A, Haas CA, Urbach H, Prinz M, Limbrick DD, Gurnett CA, Smyth MD, Sattar S, Nespeca M, Gonda DD, Imai K, Takahashi Y, Chen HH, Tsai JW, Conti V, Guerrini R, Devinsky O, Silva WA, Machado HR, Mathern GW, Abyzov A, Baldassari S, Baulac S, Gleeson JG. Comprehensive multi-omic profiling of somatic mutations in malformations of cortical development. Nat Genet 2023; 55:209-220. [PMID: 36635388 PMCID: PMC9961399 DOI: 10.1038/s41588-022-01276-9] [Citation(s) in RCA: 26] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Accepted: 11/30/2022] [Indexed: 01/14/2023]
Abstract
Malformations of cortical development (MCD) are neurological conditions involving focal disruptions of cortical architecture and cellular organization that arise during embryogenesis, largely from somatic mosaic mutations, and cause intractable epilepsy. Identifying the genetic causes of MCD has been a challenge, as mutations remain at low allelic fractions in brain tissue resected to treat condition-related epilepsy. Here we report a genetic landscape from 283 brain resections, identifying 69 mutated genes through intensive profiling of somatic mutations, combining whole-exome and targeted-amplicon sequencing with functional validation including in utero electroporation of mice and single-nucleus RNA sequencing. Genotype-phenotype correlation analysis elucidated specific MCD gene sets associated with distinct pathophysiological and clinical phenotypes. The unique single-cell level spatiotemporal expression patterns of mutated genes in control and patient brains indicate critical roles in excitatory neurogenic pools during brain development and in promoting neuronal hyperexcitability after birth.
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Affiliation(s)
- Changuk Chung
- Department of Neurosciences, University of California San Diego, La Jolla, CA, USA
- Rady Children's Institute for Genomic Medicine, San Diego, CA, USA
| | - Xiaoxu Yang
- Department of Neurosciences, University of California San Diego, La Jolla, CA, USA
- Rady Children's Institute for Genomic Medicine, San Diego, CA, USA
| | - Taejeong Bae
- Department of Quantitative Health Sciences, Center for Individualized Medicine, Mayo Clinic, Rochester, MN, USA
| | - Keng Ioi Vong
- Department of Neurosciences, University of California San Diego, La Jolla, CA, USA
- Rady Children's Institute for Genomic Medicine, San Diego, CA, USA
| | - Swapnil Mittal
- Department of Neurosciences, University of California San Diego, La Jolla, CA, USA
- Rady Children's Institute for Genomic Medicine, San Diego, CA, USA
| | - Catharina Donkels
- Department of Neurosurgery, Experimental Epilepsy Research, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - H Westley Phillips
- Department of Neurosurgery, University of California at Los Angeles, Los Angeles, CA, USA
| | - Zhen Li
- Department of Neurosciences, University of California San Diego, La Jolla, CA, USA
- Rady Children's Institute for Genomic Medicine, San Diego, CA, USA
| | - Ashley P L Marsh
- Department of Neurosciences, University of California San Diego, La Jolla, CA, USA
- Rady Children's Institute for Genomic Medicine, San Diego, CA, USA
| | - Martin W Breuss
- Department of Neurosciences, University of California San Diego, La Jolla, CA, USA
- Rady Children's Institute for Genomic Medicine, San Diego, CA, USA
- Department of Pediatrics, Section of Clinical Genetics and Metabolism, University of Colorado Aurora, Aurora, CO, USA
| | - Laurel L Ball
- Department of Neurosciences, University of California San Diego, La Jolla, CA, USA
- Rady Children's Institute for Genomic Medicine, San Diego, CA, USA
| | - Camila Araújo Bernardino Garcia
- Laboratory of Pediatric Neurosurgery and Developmental Neuropathology, Department of Surgery and Anatomy, University of São Paulo, Ribeirão Preto, Brazil
| | - Renee D George
- Department of Neurosciences, University of California San Diego, La Jolla, CA, USA
- Rady Children's Institute for Genomic Medicine, San Diego, CA, USA
| | - Jing Gu
- Department of Neurosciences, University of California San Diego, La Jolla, CA, USA
- Rady Children's Institute for Genomic Medicine, San Diego, CA, USA
| | - Mingchu Xu
- Department of Neurosciences, University of California San Diego, La Jolla, CA, USA
- Rady Children's Institute for Genomic Medicine, San Diego, CA, USA
| | - Chelsea Barrows
- Department of Neurosciences, University of California San Diego, La Jolla, CA, USA
- Rady Children's Institute for Genomic Medicine, San Diego, CA, USA
| | - Kiely N James
- Department of Neurosciences, University of California San Diego, La Jolla, CA, USA
- Rady Children's Institute for Genomic Medicine, San Diego, CA, USA
| | - Valentina Stanley
- Department of Neurosciences, University of California San Diego, La Jolla, CA, USA
- Rady Children's Institute for Genomic Medicine, San Diego, CA, USA
| | - Anna S Nidhiry
- Department of Neurosciences, University of California San Diego, La Jolla, CA, USA
- Rady Children's Institute for Genomic Medicine, San Diego, CA, USA
| | - Sami Khoury
- Department of Neurosciences, University of California San Diego, La Jolla, CA, USA
- Rady Children's Institute for Genomic Medicine, San Diego, CA, USA
| | - Gabrielle Howe
- Department of Neurosciences, University of California San Diego, La Jolla, CA, USA
- Rady Children's Institute for Genomic Medicine, San Diego, CA, USA
| | - Emily Riley
- Department of Neurosciences, University of California San Diego, La Jolla, CA, USA
- Rady Children's Institute for Genomic Medicine, San Diego, CA, USA
| | - Xin Xu
- Department of Neurosciences, University of California San Diego, La Jolla, CA, USA
- Rady Children's Institute for Genomic Medicine, San Diego, CA, USA
| | - Brett Copeland
- Department of Neurosciences, University of California San Diego, La Jolla, CA, USA
- Rady Children's Institute for Genomic Medicine, San Diego, CA, USA
| | - Yifan Wang
- Department of Quantitative Health Sciences, Center for Individualized Medicine, Mayo Clinic, Rochester, MN, USA
| | - Se Hoon Kim
- Department of Pathology, Severance Hospital, Yonsei University College of Medicine, Seoul, South Korea
| | - Hoon-Chul Kang
- Division of Pediatric Neurology, Department of Pediatrics, Severance Children's Hospital, Yonsei University College of Medicine, Seoul, South Korea
| | - Andreas Schulze-Bonhage
- Center for Basics in NeuroModulation, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Carola A Haas
- Department of Neurosurgery, Experimental Epilepsy Research, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Center for Basics in NeuroModulation, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Horst Urbach
- Department of Neuroradiology, Medical Center-University of Freiburg, Faculty of Medicine, Freiburg, Germany
| | - Marco Prinz
- Center for Basics in NeuroModulation, Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Institute of Neuropathology, Medical Center-University of Freiburg, Faculty of Medicine, Freiburg, Germany
- Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Freiburg, Germany
| | - David D Limbrick
- Department of Neurology, St. Louis Children's Hospital, Washington University St Louis, Washington, MO, USA
| | - Christina A Gurnett
- Department of Neurology, St. Louis Children's Hospital, Washington University St Louis, Washington, MO, USA
| | - Matthew D Smyth
- Department of Neurosurgery, St. Louis Children's Hospital, Washington University St Louis, Washington, MO, USA
| | - Shifteh Sattar
- Epilepsy Center, Rady Children's Hospital, San Diego, CA, USA
| | - Mark Nespeca
- Epilepsy Center, Rady Children's Hospital, San Diego, CA, USA
| | - David D Gonda
- Epilepsy Center, Rady Children's Hospital, San Diego, CA, USA
| | - Katsumi Imai
- National Epilepsy Center, NHO Shizuoka Institute of Epilepsy and Neurological Disorders, Shizuoka, Japan
| | - Yukitoshi Takahashi
- National Epilepsy Center, NHO Shizuoka Institute of Epilepsy and Neurological Disorders, Shizuoka, Japan
| | - Hsin-Hung Chen
- Division of Pediatric Neurosurgery, The Neurological Institute, Taipei Veterans General Hospital, Taipei City, Taiwan
| | - Jin-Wu Tsai
- Institute of Brain Science, Brain Research Center, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Valerio Conti
- Pediatric Neurology Unit and Laboratories, IRCCS Meyer Children's Hospital University of Florence, Firenze, Italy
| | - Renzo Guerrini
- Pediatric Neurology Unit and Laboratories, IRCCS Meyer Children's Hospital University of Florence, Firenze, Italy
| | - Orrin Devinsky
- Comprehensive Epilepsy Center, Department of Neurology, New York University Langone Health, New York, NY, USA
| | - Wilson A Silva
- Department of Genetics, Center for Cell-Based Therapy, Center for Integrative Systems Biology, University of São Paulo, Ribeirão Preto, Brazil
| | - Helio R Machado
- Laboratory of Pediatric Neurosurgery and Developmental Neuropathology, Department of Surgery and Anatomy, University of São Paulo, Ribeirão Preto, Brazil
| | - Gary W Mathern
- Department of Neurosurgery, University of California at Los Angeles, Los Angeles, CA, USA
| | - Alexej Abyzov
- Department of Quantitative Health Sciences, Center for Individualized Medicine, Mayo Clinic, Rochester, MN, USA
| | - Sara Baldassari
- Sorbonne Université, Institut du Cerveau - Paris Brain Institute - ICM, Inserm, CNRS, Hôpital de la Pitié Salpêtrière, Paris, France
| | - Stéphanie Baulac
- Sorbonne Université, Institut du Cerveau - Paris Brain Institute - ICM, Inserm, CNRS, Hôpital de la Pitié Salpêtrière, Paris, France
| | - Joseph G Gleeson
- Department of Neurosciences, University of California San Diego, La Jolla, CA, USA.
- Rady Children's Institute for Genomic Medicine, San Diego, CA, USA.
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12
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Wang Y, Yu T, Blümcke I, Cai Y, Sun K, Gao R, Wang Y, Fu Y, Wang W, Wang Y, Zhang G, Piao Y. The clinico-pathological characterisation of focal cortical dysplasia type IIb genetically defined by MTOR mosaicism. Neuropathol Appl Neurobiol 2023; 49:e12874. [PMID: 36544434 DOI: 10.1111/nan.12874] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2021] [Revised: 08/18/2022] [Accepted: 10/11/2022] [Indexed: 12/24/2022]
Abstract
AIMS Focal cortical dysplasia (FCD) is a major cause of drug-resistant paediatric epilepsy and is amenable to successful neurosurgical resection. FCD ILAE Type IIb is the most common FCD subtype, and brain somatic mutations affecting the mTOR pathway play a major pathogenic role. The aim of this study was to comprehensively describe the genotype-phenotype association of 20 patients with histopathologically confirmed FCDIIb using next generation sequencing (NGS) of paired blood-brain samples. METHODS Clinical and neuropathological data were retrospectively reviewed from the hospital archive. The NGS panel included 11 mTOR-pathway-related genes with maximum coverage of 2000×. The detected variants were validated by digital droplet PCR. RESULTS Pathogenic MTOR variants were identified in 10 patients (50%). Further comparison with MTOR-wildtype FCDIIb suggested a profound genotype-phenotype association characterised by (1) a non-temporal lobe lesion on MRI, (2) a larger lesion volume occupying grey and white matter (3.032 ± 1.859 cm3 vs 1.110 ± 0.856 cm3 , p = 0.014), (3) more balloon cells (50.20 ± 14.40 BC/mm2 vs 31.64 ± 30.56 BC/mm2 , p = 0.099) and dysmorphic neurons (48.72 ± 19.47DN/mm2 vs 15.28 ± 13.95DN/mm2 , p = 0.000) and (4) a positive correlation between VAF and the lesion volume (r = 0.802, p = 0.017). CONCLUSIONS Our study identified frequent MTOR mutations in the cell-rich FCDIIb phenotype, clinically characterised by a non-temporal location and large lesion volume. Comprehensive genotype-phenotype associations will help us further explore and define the broad spectrum of FCD lesions to make more targeted therapies available in the realm of epileptology.
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Affiliation(s)
- Yajie Wang
- Department of Pathology, Xuanwu Hospital, Capital Medical University, Beijing, China.,Clinical Research Center for Epilepsy, Capital Medical University, Beijing, China.,National Center for Neurological Disorders, Beijing, China
| | - Tao Yu
- Clinical Research Center for Epilepsy, Capital Medical University, Beijing, China.,National Center for Neurological Disorders, Beijing, China.,Beijing Institute of Functional Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing, China.,Department of Functional Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Ingmar Blümcke
- Department of Neuropathology, University Hospital Erlangen, Erlangen, Germany
| | - Yanning Cai
- Clinical Research Center for Epilepsy, Capital Medical University, Beijing, China.,National Center for Neurological Disorders, Beijing, China.,Department of Neurobiology and Clinical Biobank, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Ke Sun
- Clinical Research Center for Epilepsy, Capital Medical University, Beijing, China.,National Center for Neurological Disorders, Beijing, China.,Beijing Institute of Functional Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing, China.,Department of Functional Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Runshi Gao
- Clinical Research Center for Epilepsy, Capital Medical University, Beijing, China.,National Center for Neurological Disorders, Beijing, China.,Beijing Institute of Functional Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing, China.,Department of Functional Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Yujiao Wang
- Department of Pathology, Xuanwu Hospital, Capital Medical University, Beijing, China.,Clinical Research Center for Epilepsy, Capital Medical University, Beijing, China.,National Center for Neurological Disorders, Beijing, China
| | - Yongjuan Fu
- Department of Pathology, Xuanwu Hospital, Capital Medical University, Beijing, China.,Clinical Research Center for Epilepsy, Capital Medical University, Beijing, China.,National Center for Neurological Disorders, Beijing, China
| | - Wei Wang
- Clinical Research Center for Epilepsy, Capital Medical University, Beijing, China.,National Center for Neurological Disorders, Beijing, China.,Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Yuping Wang
- Clinical Research Center for Epilepsy, Capital Medical University, Beijing, China.,National Center for Neurological Disorders, Beijing, China.,Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, China.,Beijing Key Laboratory of Neuromodulation, Beijing, China.,Center of Epilepsy, Institute of Sleep and Consciousness Disorders, Beijing Institute for Brain Disorders, Capital Medical University, Beijing, China
| | - Guojun Zhang
- Clinical Research Center for Epilepsy, Capital Medical University, Beijing, China.,National Center for Neurological Disorders, Beijing, China.,Beijing Institute of Functional Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing, China.,Department of Functional Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Yueshan Piao
- Department of Pathology, Xuanwu Hospital, Capital Medical University, Beijing, China.,Clinical Research Center for Epilepsy, Capital Medical University, Beijing, China.,National Center for Neurological Disorders, Beijing, China
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13
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Townsend SE, Westfall JJ, Navarro JB, Koboldt DC, Mardis ER, Miller KE, Bedrosian TA. Single-nuclei transcriptomics enable detection of somatic variants in patient brain tissue. Sci Rep 2023; 13:527. [PMID: 36631516 PMCID: PMC9834227 DOI: 10.1038/s41598-023-27700-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Accepted: 01/06/2023] [Indexed: 01/12/2023] Open
Abstract
Somatic variants are a major cause of human disease, including neurological disorders like focal epilepsies, but can be challenging to study due to their mosaicism in bulk tissue biopsies. Coupling single-cell genotype and transcriptomic data has potential to provide insight into the role somatic variants play in disease etiology, such as by determining what cell types are affected or how the mutations affect gene expression. Here, we asked whether commonly used single-nucleus 3'- or 5'-RNA-sequencing assays can be used to derive single-nucleus genotype data for a priori known variants that are located near to either end of a transcript. To that end, we compared performance of commercially available single-nuclei 3'- and 5'- gene expression kits using resected brain samples from three pediatric patients with focal epilepsy. We quantified the ability to detect genetic variants in single-nucleus datasets depending on distance from the transcript end. Finally, we demonstrated the ability to identify affected cell types in a patient with a RHEB somatic variant causing an epilepsy-associated cortical malformation. Our results demonstrate that single-nuclei 3' or 5'-RNA-sequencing data can be used to identify known somatic variants in single-nuclei when they are expressed within proximity to a transcript end.
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Affiliation(s)
- Sydney E. Townsend
- grid.240344.50000 0004 0392 3476Institute for Genomic Medicine, The Abigail Wexner Research Institute at Nationwide Children’s Hospital, Columbus, OH 43215 USA ,grid.261331.40000 0001 2285 7943Biomedical Sciences Graduate Program, College of Medicine, The Ohio State University, Columbus, OH 43210 USA
| | - Jesse J. Westfall
- grid.240344.50000 0004 0392 3476Institute for Genomic Medicine, The Abigail Wexner Research Institute at Nationwide Children’s Hospital, Columbus, OH 43215 USA
| | - Jason B. Navarro
- grid.240344.50000 0004 0392 3476Institute for Genomic Medicine, The Abigail Wexner Research Institute at Nationwide Children’s Hospital, Columbus, OH 43215 USA
| | - Daniel C. Koboldt
- grid.240344.50000 0004 0392 3476Institute for Genomic Medicine, The Abigail Wexner Research Institute at Nationwide Children’s Hospital, Columbus, OH 43215 USA ,grid.261331.40000 0001 2285 7943Department of Pediatrics, College of Medicine, The Ohio State University, Columbus, OH 43210 USA
| | - Elaine R. Mardis
- grid.240344.50000 0004 0392 3476Institute for Genomic Medicine, The Abigail Wexner Research Institute at Nationwide Children’s Hospital, Columbus, OH 43215 USA ,grid.261331.40000 0001 2285 7943Department of Pediatrics, College of Medicine, The Ohio State University, Columbus, OH 43210 USA ,grid.261331.40000 0001 2285 7943Department of Neurosurgery, College of Medicine, The Ohio State University, Columbus, OH 43210 USA
| | - Katherine E. Miller
- grid.240344.50000 0004 0392 3476Institute for Genomic Medicine, The Abigail Wexner Research Institute at Nationwide Children’s Hospital, Columbus, OH 43215 USA ,grid.261331.40000 0001 2285 7943Department of Pediatrics, College of Medicine, The Ohio State University, Columbus, OH 43210 USA
| | - Tracy A. Bedrosian
- grid.240344.50000 0004 0392 3476Institute for Genomic Medicine, The Abigail Wexner Research Institute at Nationwide Children’s Hospital, Columbus, OH 43215 USA ,grid.261331.40000 0001 2285 7943Department of Pediatrics, College of Medicine, The Ohio State University, Columbus, OH 43210 USA
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14
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Murzaeva DA, Sitovskaya DA, Sultygova KA, Sabanchieva DD, Kiseleva MA, Verbitskiy OP, Zabrodskaya YM. Hemimegalencephaly associated with drug-resistant epilepsy and a rare molecular genetic alteration in the CPA6 gene: a clinical case. SECHENOV MEDICAL JOURNAL 2022. [DOI: 10.47093/2218-7332.2022.13.2.4-11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Hemimegalencephaly (HME) is one of the extremely rare congenital malformations of cortical development (MCD). It belongs to the MCD group of mTOR-related pathologies and can be the result of various genetic disorders. One of the main clinical manifestations of HME is drug-resistant epilepsy requiring surgical treatment.Case report. This article describes a clinical case of HME in a 4-year-old boy with frequent generalized tonic-clonic seizures and drug-resistant epilepsy; also, he had speech development delay. MRI revealed a HME of the right frontal lobe. Stereotaxic laser disconnection of the large cortical dysplasia in the right frontal lobe of the brain was performed. Morphological features of focal cortical dysplasia type IIb (FCD IIb) were reported. No seizures were observed in the hospital follow up after the operation for 14 days. The whole exome DNA sequencing showed the presence of a heterozygous state _000008.10^G 68419028del / 633del, pGlu212LysfsTers of the CPA6 gene.Discussion. A feature of the case is the identified association of HME, morphologically represented by FCD IIb, with a previously unknown heterozygous state in the 6th exon of the CPA6 gene. This association allows to expand our understanding of changes in the activation of PI3K/AKT/mTOR pathway as a key link in the pathogenesis of congenital anomaly of cortical development.
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Affiliation(s)
- D. A. Murzaeva
- Polenov Neurosurgical Institute, Branch of Almazov National Medical Research Centre
| | - D. A. Sitovskaya
- Polenov Neurosurgical Institute, Branch of Almazov National Medical Research Centre; City Mariinsky Hospital
| | - K. A. Sultygova
- Granov Russian Research Center of Radiology and Surgical Technologies
| | | | | | | | - Yu. M. Zabrodskaya
- Polenov Neurosurgical Institute, Branch of Almazov National Medical Research Centre
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15
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Najm I, Lal D, Alonso Vanegas M, Cendes F, Lopes-Cendes I, Palmini A, Paglioli E, Sarnat HB, Walsh CA, Wiebe S, Aronica E, Baulac S, Coras R, Kobow K, Cross JH, Garbelli R, Holthausen H, Rössler K, Thom M, El-Osta A, Lee JH, Miyata H, Guerrini R, Piao YS, Zhou D, Blümcke I. The ILAE consensus classification of focal cortical dysplasia: An update proposed by an ad hoc task force of the ILAE diagnostic methods commission. Epilepsia 2022; 63:1899-1919. [PMID: 35706131 PMCID: PMC9545778 DOI: 10.1111/epi.17301] [Citation(s) in RCA: 93] [Impact Index Per Article: 46.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Revised: 04/24/2022] [Accepted: 05/13/2022] [Indexed: 02/05/2023]
Abstract
Ongoing challenges in diagnosing focal cortical dysplasia (FCD) mandate continuous research and consensus agreement to improve disease definition and classification. An International League Against Epilepsy (ILAE) Task Force (TF) reviewed the FCD classification of 2011 to identify existing gaps and provide a timely update. The following methodology was applied to achieve this goal: a survey of published literature indexed with ((Focal Cortical Dysplasia) AND (epilepsy)) between 01/01/2012 and 06/30/2021 (n = 1349) in PubMed identified the knowledge gained since 2012 and new developments in the field. An online survey consulted the ILAE community about the current use of the FCD classification scheme with 367 people answering. The TF performed an iterative clinico-pathological and genetic agreement study to objectively measure the diagnostic gap in blood/brain samples from 22 patients suspicious for FCD and submitted to epilepsy surgery. The literature confirmed new molecular-genetic characterizations involving the mechanistic Target Of Rapamycin (mTOR) pathway in FCD type II (FCDII), and SLC35A2 in mild malformations of cortical development (mMCDs) with oligodendroglial hyperplasia (MOGHE). The electro-clinical-imaging phenotypes and surgical outcomes were better defined and validated for FCDII. Little new information was acquired on clinical, histopathological, or genetic characteristics of FCD type I (FCDI) and FCD type III (FCDIII). The survey identified mMCDs, FCDI, and genetic characterization as fields for improvement in an updated classification. Our iterative clinico-pathological and genetic agreement study confirmed the importance of immunohistochemical staining, neuroimaging, and genetic tests to improve the diagnostic yield. The TF proposes to include mMCDs, MOGHE, and "no definite FCD on histopathology" as new categories in the updated FCD classification. The histopathological classification can be further augmented by advanced neuroimaging and genetic studies to comprehensively diagnose FCD subtypes; these different levels should then be integrated into a multi-layered diagnostic scheme. This update may help to foster multidisciplinary efforts toward a better understanding of FCD and the development of novel targeted treatment options.
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Affiliation(s)
- Imad Najm
- Charles Shor Epilepsy Center, Neurological Institute, Cleveland, Ohio, USA
| | - Dennis Lal
- Charles Shor Epilepsy Center, Neurological Institute, Cleveland, Ohio, USA.,Genomic Medicine Institute, Cleveland Clinic, Cleveland, Ohio, USA
| | | | - Fernando Cendes
- Brazilian Institute of Neuroscience and Neurotechnology (BRAINN), University of Campinas - UNICAMP, Campinas, Sao Paulo, Brazil.,Department of Neurology, University of Campinas - UNICAMP, Campinas, Sao Paulo, Brazil
| | - Iscia Lopes-Cendes
- Brazilian Institute of Neuroscience and Neurotechnology (BRAINN), University of Campinas - UNICAMP, Campinas, Sao Paulo, Brazil.,Department of Translational Medicine, University of Campinas - UNICAMP, Campinas, Sao Paulo, Brazil
| | - Andre Palmini
- Department of Clinical Neurosciences, School of Medicine, Pontificia Universidade Católica do Rio Grande do Sul (PUCRS), Porto Alegre, Brazil.,Porto Alegre Epilepsy Surgery Program, Hospital São Lucas PUCRS, Porto Alegre, Brazil
| | - Eliseu Paglioli
- Department of Surgery, School of Medicine, Pontificia Universidade Católica do Rio Grande do Sul (PUCRS), Porto Alegre, Brazil
| | - Harvey B Sarnat
- Department of Paediatrics, Department of Pathology (Neuropathology) and Department of Clinical Neurosciences, University of Calgary Faculty of Medicine, Alberta Children's Hospital Research Institute, Calgary, Alberta, Canada
| | - Christopher A Walsh
- Division of Genetics and Genomics and Howard Hughes Medical Institute, Department of Pediatrics, Boston Children's Hospital, Boston, Massachusetts, USA.,Departments of Pediatrics and Neurology, Harvard Medical School, Boston, Massachusetts, USA
| | - Samuel Wiebe
- Department of Clinical Neurosciences, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Eleonora Aronica
- Department of (Neuro) Pathology, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands.,Stichting Epilepsie Instellingen Nederland (SEIN), Heemstede, the Netherlands
| | - Stéphanie Baulac
- Sorbonne Université, Institut du Cerveau - Paris Brain Institute - ICM, Inserm, CNRS, APHP, Hôpital de la Pitié Salpêtrière, Paris, France
| | - Roland Coras
- Department of Neuropathology, Universitätsklinikum Erlangen, Erlangen, Germany
| | - Katja Kobow
- Developmental Neurosciences Programme, UCL NIHR BRC Great Ormond Street Institute of Child Health and Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
| | - J Helen Cross
- Developmental Neurosciences Programme, UCL NIHR BRC Great Ormond Street Institute of Child Health and Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
| | - Rita Garbelli
- Epilepsy Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Hans Holthausen
- Center for Pediatric Neurology, Neurorehabilitation and Epileptology, Schoen-Clinic, Vogtareuth, Germany
| | - Karl Rössler
- Department of Neurosurgery, Allgemeines Krankenhaus Wien, Vienna Medical University, Wien, Austria
| | - Maria Thom
- Department of Neuropathology, Institute of Neurology, University College London, UK
| | - Assam El-Osta
- Epigenetics in Human Health and Disease Laboratory, Central Clinical School, Monash University, Melbourne, Victoria, Australia
| | - Jeong Ho Lee
- Graduate School of Medical Science and Engineering, KAIST and SoVarGen, Daejeon, South Korea
| | - Hajime Miyata
- Department of Neuropathology, Research Institute for Brain and Blood Vessels, Akita Cerebrospinal and Cardiovascular Center, Akita, Japan
| | - Renzo Guerrini
- Neuroscience Department, Children's Hospital Anna Meyer- University of Florence, Florence, Italy
| | - Yue-Shan Piao
- National Center for Neurological Disorders, Department of Pathology, Xuanwu Hospital, Capital Medical University, and Clinical Research Center for Epilepsy, Capital Medical University, Beijing, China
| | - Dong Zhou
- Department of Neurology, West China Hospital, Sichuan University, Chengdu, China
| | - Ingmar Blümcke
- Charles Shor Epilepsy Center, Neurological Institute, Cleveland, Ohio, USA.,Department of Neuropathology, Universitätsklinikum Erlangen, Erlangen, Germany
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16
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Moloney PB, Dugan P, Widdess-Walsh P, Devinsky O, Delanty N. Genomics in the Presurgical Epilepsy Evaluation. Epilepsy Res 2022; 184:106951. [DOI: 10.1016/j.eplepsyres.2022.106951] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Revised: 04/23/2022] [Accepted: 05/25/2022] [Indexed: 11/03/2022]
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17
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Hoffmann L, Blümcke I. Neuropathology and epilepsy surgery. Curr Opin Neurol 2022; 35:202-207. [PMID: 35067500 DOI: 10.1097/wco.0000000000001030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE OF REVIEW Neurosurgical treatment of patients suffering from drug-resistant focal epilepsy is recognized as a successful, yet underutilized medical treatment option. By searching PubMed for articles published between January 2020 and September 2021 with the broad search terms 'neuropathology' AND 'epilepsy surgery', this review highlights the active field of etiology-based epilepsy research in human tissue. RECENT FINDINGS All papers addressing the most common epileptogenic human brain disease entities, i.e. focal cortical dysplasia (FCD), brain tumors or hippocampal sclerosis, and written in English language were eligible for our review. We can conclude from this review that etiology-based studies are of foremost interest for (1) the development of prediction models for postsurgical seizure outcome; (2) decipher genetic and molecular alterations to better define disease entities and underlying molecular pathomechanisms, and (3) the translation of human tissue-derived biomarker into clinically useful diagnostics or novel therapeutic targets in the near future. SUMMARY Highlighting FCD brain somatic gain-of-function variants in mammalian target of Rapamycin are a leading pathway to better classify FCD. An integrated genotype-phenotype analysis enables to classify the broad spectrum of low-grade and epilepsy-associated brain tumors. Further DNA-methylation-based disease classification will increase the mechanistic understanding and diagnostic precision of difficult to classify pathologies in the future.
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Affiliation(s)
- Lucas Hoffmann
- Department of Neuropathology, University Hospital Erlangen, Erlangen, Germany
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18
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Genetic mosaicism in the human brain: from lineage tracing to neuropsychiatric disorders. Nat Rev Neurosci 2022; 23:275-286. [PMID: 35322263 DOI: 10.1038/s41583-022-00572-x] [Citation(s) in RCA: 29] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/11/2022] [Indexed: 12/18/2022]
Abstract
Genetic mosaicism is the result of the accumulation of somatic mutations in the human genome starting from the first postzygotic cell generation and continuing throughout the whole life of an individual. The rapid development of next-generation and single-cell sequencing technologies is now allowing the study of genetic mosaicism in normal tissues, revealing unprecedented insights into their clonal architecture and physiology. The somatic variant repertoire of an adult human neuron is the result of somatic mutations that accumulate in the brain by different mechanisms and at different rates during development and ageing. Non-pathogenic developmental mutations function as natural barcodes that once identified in deep bulk or single-cell sequencing can be used to retrospectively reconstruct human lineages. This approach has revealed novel insights into the clonal structure of the human brain, which is a mosaic of clones traceable to the early embryo that contribute differentially to the brain and distinct areas of the cortex. Some of the mutations happening during development, however, have a pathogenic effect and can contribute to some epileptic malformations of cortical development and autism spectrum disorder. In this Review, we discuss recent findings in the context of genetic mosaicism and their implications for brain development and disease.
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19
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Cortical Dysplasia and the mTOR Pathway: How the Study of Human Brain Tissue Has Led to Insights into Epileptogenesis. Int J Mol Sci 2022; 23:ijms23031344. [PMID: 35163267 PMCID: PMC8835853 DOI: 10.3390/ijms23031344] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 01/14/2022] [Accepted: 01/16/2022] [Indexed: 02/01/2023] Open
Abstract
Type II focal cortical dysplasia (FCD) is a neuropathological entity characterised by cortical dyslamination with the presence of dysmorphic neurons only (FCDIIA) or the presence of both dysmorphic neurons and balloon cells (FCDIIB). The year 2021 marks the 50th anniversary of the recognition of FCD as a cause of drug resistant epilepsy, and it is now the most common reason for epilepsy surgery. The causes of FCD remained unknown until relatively recently. The study of resected human FCD tissue using novel genomic technologies has led to remarkable advances in understanding the genetic basis of FCD. Mechanistic parallels have emerged between these non-neoplastic lesions and neoplastic disorders of cell growth and differentiation, especially through perturbations of the mammalian target of rapamycin (mTOR) signalling pathway. This narrative review presents the advances through which the aetiology of FCDII has been elucidated in chronological order, from recognition of an association between FCD and the mTOR pathway to the identification of somatic mosaicism within FCD tissue. We discuss the role of a two-hit mechanism, highlight current challenges and future directions in detecting somatic mosaicism in brain and discuss how knowledge of FCD may inform novel precision treatments of these focal epileptogenic malformations of human cortical development.
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20
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Roy A, Han VZ, Bard AM, Wehle DT, Smith SEP, Ramirez JM, Kalume F, Millen KJ. Non-synaptic Cell-Autonomous Mechanisms Underlie Neuronal Hyperactivity in a Genetic Model of PIK3CA-Driven Intractable Epilepsy. Front Mol Neurosci 2021; 14:772847. [PMID: 34899181 PMCID: PMC8662737 DOI: 10.3389/fnmol.2021.772847] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Accepted: 10/20/2021] [Indexed: 12/26/2022] Open
Abstract
Patients harboring mutations in the PI3K-AKT-MTOR pathway-encoding genes often develop a spectrum of neurodevelopmental disorders including epilepsy. A significant proportion remains unresponsive to conventional anti-seizure medications. Understanding mutation-specific pathophysiology is thus critical for molecularly targeted therapies. We previously determined that mouse models expressing a patient-related activating mutation in PIK3CA, encoding the p110α catalytic subunit of phosphoinositide-3-kinase (PI3K), are epileptic and acutely treatable by PI3K inhibition, irrespective of dysmorphology. Here we report the physiological mechanisms underlying this dysregulated neuronal excitability. In vivo, we demonstrate epileptiform events in the Pik3ca mutant hippocampus. By ex vivo analyses, we show that Pik3ca-driven hyperactivation of hippocampal pyramidal neurons is mediated by changes in multiple non-synaptic, cell-intrinsic properties. Finally, we report that acute inhibition of PI3K or AKT, but not MTOR activity, suppresses the intrinsic hyperactivity of the mutant neurons. These acute mechanisms are distinct from those causing neuronal hyperactivity in other AKT-MTOR epileptic models and define parameters to facilitate the development of new molecularly rational therapeutic interventions for intractable epilepsy.
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Affiliation(s)
- Achira Roy
- Neuroscience Unit, Jawaharlal Nehru Centre for Advanced Scientific Research (JNCASR), Bengaluru, India
| | - Victor Z Han
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, United States.,Department of Biology, University of Washington, Seattle, WA, United States
| | - Angela M Bard
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, United States
| | - Devin T Wehle
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, United States.,Graduate Program in Neuroscience, University of Washington, Seattle, WA, United States
| | - Stephen E P Smith
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, United States.,Department of Pediatrics, University of Washington, Seattle, WA, United States
| | - Jan-Marino Ramirez
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, United States.,Department of Pediatrics, University of Washington, Seattle, WA, United States.,Department of Neurological Surgery, University of Washington, Seattle, WA, United States.,Department of Physiology and Biophysics, University of Washington, Seattle, WA, United States
| | - Franck Kalume
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, United States.,Department of Neurological Surgery, University of Washington, Seattle, WA, United States.,Department of Pharmacology, University of Washington, Seattle, WA, United States
| | - Kathleen J Millen
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, United States.,Department of Pediatrics, University of Washington, Seattle, WA, United States
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21
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Neocortical development and epilepsy: insights from focal cortical dysplasia and brain tumours. Lancet Neurol 2021; 20:943-955. [PMID: 34687638 DOI: 10.1016/s1474-4422(21)00265-9] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Revised: 07/14/2021] [Accepted: 08/05/2021] [Indexed: 01/16/2023]
Abstract
During the past decade, there have been considerable advances in understanding of the genetic and morphogenic processes underlying cortical malformations and developmental brain tumours. Focal malformations are caused by somatic (postzygotic) variants in genes related to cell growth (ie, in the mTOR pathway in focal cortical dysplasia type 2), which are acquired in neuronal progenitors during neurodevelopment. In comparison, developmental brain tumours result from somatic variants in genes related to cell proliferation (eg, in the MAP-kinase pathway in ganglioglioma), which affect proliferating glioneuronal precursors. The timing of the genetic event and the specific gene involved during neurodevelopment will drive the nature and size of the lesion, whether it is a developmental malformation or a brain tumour. There is also emerging evidence that epigenetic processes underlie a molecular memory in epileptogenesis. This knowledge will together facilitate understanding of why and how patients with these lesions have epilepsy, and could form a basis for a move towards precision medicine for this challenging cohort of patients.
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22
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Kobow K, Baulac S, von Deimling A, Lee JH. Molecular diagnostics in drug-resistant focal epilepsy define new disease entities. Brain Pathol 2021; 31:e12963. [PMID: 34196984 PMCID: PMC8412082 DOI: 10.1111/bpa.12963] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Accepted: 03/31/2021] [Indexed: 01/16/2023] Open
Abstract
Structural brain lesions, including the broad range of malformations of cortical development (MCD) and glioneuronal tumors, are among the most common causes of drug-resistant focal epilepsy. Epilepsy surgery can provide a curative treatment option in respective patients. The currently available pre-surgical multi-modal diagnostic armamentarium includes high- and ultra-high resolution magnetic resonance imaging (MRI) and intracerebral EEG to identify a focal structural brain lesion as epilepsy underlying etiology. However, specificity and accuracy in diagnosing the type of lesion have proven to be limited. Moreover, the diagnostic process does not stop with the decision for surgery. The neuropathological diagnosis remains the gold standard for disease classification and patient stratification, but is particularly complex with high inter-observer variability. Here, the identification of lesion-specific mosaic variants together with epigenetic profiling of lesional brain tissue became new tools to more reliably identify disease entities. In this review, we will discuss how the paradigm shifts from histopathology toward an integrated diagnostic approach in cancer and the more recent development of the DNA methylation-based brain tumor classifier have started to influence epilepsy diagnostics. Some examples will be highlighted showing how the diagnosis and our mechanistic understanding of difficult to classify structural brain lesions associated with focal epilepsy has improved with molecular genetic data being considered in decision making.
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Affiliation(s)
- Katja Kobow
- Department of NeuropathologyUniversitätsklinikum ErlangenFriedrich‐Alexander‐University of Erlangen‐Nürnberg (FAU)ErlangenGermany
| | - Stéphanie Baulac
- Institut du Cerveau—Paris Brain Institute—ICMInsermCNRSSorbonne UniversitéParisFrance
| | - Andreas von Deimling
- Department of NeuropathologyUniversitätsklinikum HeidelbergHeidelbergGermany
- CCU NeuropathologyGerman Cancer Research Center (DKFZ)HeidelbergGermany
| | - Jeong Ho Lee
- Graduate School of Medical Science and EngineeringKAISTDaejeonKorea
- SoVarGen, IncDaejeonRepublic of Korea
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