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Keever KM, Li Y, Womble PD, Sullens DG, Otazu GH, Lugo JN, Ramos RL. Neocortical and cerebellar malformations affect flurothyl-induced seizures in female C57BL/6J mice. Front Neurosci 2023; 17:1271744. [PMID: 38027492 PMCID: PMC10651747 DOI: 10.3389/fnins.2023.1271744] [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] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Accepted: 10/03/2023] [Indexed: 12/01/2023] Open
Abstract
Brain malformations cause cognitive disability and seizures in both human and animal models. Highly laminated structures such as the neocortex and cerebellum are vulnerable to malformation, affecting lamination and neuronal connectivity as well as causing heterotopia. The objective of the present study was to determine if sporadic neocortical and/or cerebellar malformations in C57BL/6J mice are correlated with reduced seizure threshold. The inhaled chemi-convulsant flurothyl was used to induce generalized, tonic-clonic seizures in male and female C57BL/6J mice, and the time to seizure onset was recorded as a functional correlate of brain excitability changes. Following seizures, mice were euthanized, and brains were extracted for histology. Cryosections of the neocortex and cerebellar vermis were stained and examined for the presence of molecular layer heterotopia as previously described in C57BL/6J mice. Over 60% of mice had neocortical and/or cerebellar heterotopia. No sex differences were observed in the prevalence of malformations. Significantly reduced seizure onset time was observed dependent on sex and the type of malformation present. These results raise important questions regarding the presence of malformations in C57BL/6J mice used in the study of brain development, epilepsy, and many other diseases of the nervous system.
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Affiliation(s)
- Katherine M. Keever
- Department of Biomedical Sciences, New York Institute of Technology College of Osteopathic Medicine, Old Westbury, NY, United States
| | - Ying Li
- Department of Biomedical Sciences, New York Institute of Technology College of Osteopathic Medicine, Old Westbury, NY, United States
| | - Paige D. Womble
- Department of Psychology and Neuroscience, Baylor University, Waco, TX, United States
| | - D. Gregory Sullens
- Department of Psychology and Neuroscience, Baylor University, Waco, TX, United States
| | - Gonzalo H. Otazu
- Department of Biomedical Sciences, New York Institute of Technology College of Osteopathic Medicine, Old Westbury, NY, United States
| | - Joaquin N. Lugo
- Department of Psychology and Neuroscience, Baylor University, Waco, TX, United States
| | - Raddy L. Ramos
- Department of Biomedical Sciences, New York Institute of Technology College of Osteopathic Medicine, Old Westbury, NY, United States
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Otazu GH, Li Y, Lodato Z, Elnasher A, Keever KM, Li Y, Ramos RL. Neurodevelopmental malformations of the cerebellum and neocortex in the Shank3 and Cntnap2 mouse models of autism. Neurosci Lett 2021; 765:136257. [PMID: 34555490 DOI: 10.1016/j.neulet.2021.136257] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [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: 04/30/2021] [Revised: 09/15/2021] [Accepted: 09/16/2021] [Indexed: 12/28/2022]
Abstract
There are many mouse models of autism with broad use in neuroscience research. Genetic background can be a major contributor to the phenotype observed in any mouse model of disease, including genetic models of autism. C57BL/6 mice display spontaneous glio-neuronal heterotopia in the cerebellar vermis and neocortex which may also exist in mouse models of autism created on this background. In the present report, we document the presence of cerebellar and neocortical heterotopia in heterozygous and KO Shank3 and Cntnap2 mice which are due to the C57BL/6 genotype and discuss the role these malformations may play in research using these genetic models of autism.
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Affiliation(s)
- Gonzalo H Otazu
- Department of Biomedical Sciences, New York Institute of Technology College of Osteopathic Medicine, Old Westbury, NY 11568, United States
| | - Yan Li
- Department of Biomedical Sciences, New York Institute of Technology College of Osteopathic Medicine, Old Westbury, NY 11568, United States
| | - Zachary Lodato
- Department of Biomedical Sciences, New York Institute of Technology College of Osteopathic Medicine, Old Westbury, NY 11568, United States
| | - Adel Elnasher
- Department of Biomedical Sciences, New York Institute of Technology College of Osteopathic Medicine, Old Westbury, NY 11568, United States
| | - Katherine M Keever
- Department of Biomedical Sciences, New York Institute of Technology College of Osteopathic Medicine, Old Westbury, NY 11568, United States
| | - Ying Li
- Department of Biomedical Sciences, New York Institute of Technology College of Osteopathic Medicine, Old Westbury, NY 11568, United States
| | - Raddy L Ramos
- Department of Biomedical Sciences, New York Institute of Technology College of Osteopathic Medicine, Old Westbury, NY 11568, United States.
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Winawer MR, Griffin NG, Samanamud J, Baugh EH, Rathakrishnan D, Ramalingam S, Zagzag D, Schevon CA, Dugan P, Hegde M, Sheth SA, McKhann GM, Doyle WK, Grant GA, Porter BE, Mikati MA, Muh CR, Malone CD, Bergin AMR, Peters JM, McBrian DK, Pack AM, Akman CI, LaCoursiere CM, Keever KM, Madsen JR, Yang E, Lidov HG, Shain C, Allen AS, Canoll P, Crino PB, Poduri AH, Heinzen EL. Somatic SLC35A2 variants in the brain are associated with intractable neocortical epilepsy. Ann Neurol 2018; 83:1133-1146. [PMID: 29679388 PMCID: PMC6105543 DOI: 10.1002/ana.25243] [Citation(s) in RCA: 76] [Impact Index Per Article: 12.7] [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: 01/23/2018] [Revised: 04/01/2018] [Accepted: 04/18/2018] [Indexed: 12/27/2022]
Abstract
OBJECTIVE Somatic variants are a recognized cause of epilepsy-associated focal malformations of cortical development (MCD). We hypothesized that somatic variants may underlie a wider range of focal epilepsy, including nonlesional focal epilepsy (NLFE). Through genetic analysis of brain tissue, we evaluated the role of somatic variation in focal epilepsy with and without MCD. METHODS We identified somatic variants through high-depth exome and ultra-high-depth candidate gene sequencing of DNA from epilepsy surgery specimens and leukocytes from 18 individuals with NLFE and 38 with focal MCD. RESULTS We observed somatic variants in 5 cases in SLC35A2, a gene associated with glycosylation defects and rare X-linked epileptic encephalopathies. Nonsynonymous variants in SLC35A2 were detected in resected brain, and absent from leukocytes, in 3 of 18 individuals (17%) with NLFE, 1 female and 2 males, with variant allele frequencies (VAFs) in brain-derived DNA of 2 to 14%. Pathologic evaluation revealed focal cortical dysplasia type Ia (FCD1a) in 2 of the 3 NLFE cases. In the MCD cohort, nonsynonymous variants in SCL35A2 were detected in the brains of 2 males with intractable epilepsy, developmental delay, and magnetic resonance imaging suggesting FCD, with VAFs of 19 to 53%; Evidence for FCD was not observed in either brain tissue specimen. INTERPRETATION We report somatic variants in SLC35A2 as an explanation for a substantial fraction of NLFE, a largely unexplained condition, as well as focal MCD, previously shown to result from somatic mutation but until now only in PI3K-AKT-mTOR pathway genes. Collectively, our findings suggest a larger role than previously recognized for glycosylation defects in the intractable epilepsies. Ann Neurol 2018.
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Affiliation(s)
- Melodie R. Winawer
- Gertrude H. Sergievsky Center, Columbia University, New York, NY 10032, USA
- Department of Neurology, Columbia University, New York, NY 10032, USA
| | - Nicole G. Griffin
- Institute for Genomic Medicine, Columbia University, New York, NY, 10032, USA
| | - Jorge Samanamud
- Department of Neurosurgery, Columbia University, New York Presbyterian Hospital, New York, NY, 10032, USA
| | - Evan H. Baugh
- Institute for Genomic Medicine, Columbia University, New York, NY, 10032, USA
| | | | | | - David Zagzag
- Department of Pathology, New York University Langone Medical Center, New York, NY, 10016, USA
- Department of Neurosurgery, New York University Langone Medical Center, New York, NY, 10016, USA
| | | | - Patricia Dugan
- Department of Neurology, New York University Langone Medical Center, New York, NY, 10016, USA
| | - Manu Hegde
- Department of Neurology, University of California, San Francisco, San Francisco, CA 94143 USA
| | - Sameer A. Sheth
- Department of Neurological Surgery, Columbia University, New York, NY, 10032, USA
| | - Guy M. McKhann
- Department of Neurological Surgery, Columbia University, New York, NY, 10032, USA
| | - Werner K. Doyle
- Department of Neurosurgery, New York University Langone Medical Center, New York, NY, 10016, USA
| | - Gerald A. Grant
- Department of Neurosurgery, Lucile Packard Children’s Hospital at Stanford, Stanford, CA, 94305, USA
| | - Brenda E. Porter
- Department of Neurology, Lucile Packard Children’s Hospital at Stanford, Stanford, CA 94305
| | - Mohamad A. Mikati
- Division of Pediatric Neurology, Duke University Medical Center, Durham, NC, 27710, USA
- Department of Neurobiology, Duke University, Durham, NC, 27708, USA
| | - Carrie R. Muh
- Department of Neurosurgery, Duke University Medical Center, Durham, NC, 27708, USA
| | - Colin D. Malone
- Institute for Genomic Medicine, Columbia University, New York, NY, 10032, USA
| | - Ann Marie R. Bergin
- Department of Neurology, Harvard Medical School, Boston, MA, 02115, USA
- Division of Epilepsy and Clinical Neurophysiology, Department of Neurology, Boston Children’s Hospital, Boston, MA, 02115, USA
| | - Jurriaan M. Peters
- Department of Neurology, Harvard Medical School, Boston, MA, 02115, USA
- Division of Epilepsy and Clinical Neurophysiology, Department of Neurology, Boston Children’s Hospital, Boston, MA, 02115, USA
| | - Danielle K. McBrian
- Division of Pediatric Neurology, Columbia University, New York, NY, 10032, USA
| | - Alison M. Pack
- Department of Neurology, Columbia University, New York, NY 10032, USA
| | - Cigdem I. Akman
- Division of Pediatric Neurology, Columbia University, New York, NY, 10032, USA
| | | | - Katherine M. Keever
- Department of Neurology, Translational Neuroscience Center, Boston Children’s Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Joseph R. Madsen
- Department of Neurosurgery, Boston Children’s Hospital and Department of Neurosurgery, Harvard Medical School, Boston, MA, 02115, USA
| | - Edward Yang
- Department of Radiology, Boston Children’s Hospital and Department of Radiology, Harvard Medical School, Boston, MA, 02115, USA
| | - Hart G.W. Lidov
- Department of Pathology, Boston Children’s Hospital and Department of Pathology, Harvard Medical School, Boston, MA, 02115, USA
| | - Catherine Shain
- Epilepsy Genetics Program, Department of Neurology, Boston Children’s Hospital, Boston, MA, 02115, USA
| | - Andrew S. Allen
- Department of Biostatistics and Bioinformatics, Duke University, Durham, NC, 27710, USA
| | - Peter Canoll
- Department of Pathology and Cell Biology, Columbia University, New York, NY, 10032, USA
| | - Peter B. Crino
- Department of Neurology, University of Maryland, School of Medicine, Baltimore, MD, 21201, USA
| | - Annapurna H. Poduri
- Department of Neurology, Harvard Medical School, Boston, MA, 02115, USA
- Division of Epilepsy and Clinical Neurophysiology, Department of Neurology, Boston Children’s Hospital, Boston, MA, 02115, USA
- Epilepsy Genetics Program, Department of Neurology, Boston Children’s Hospital, Boston, MA, 02115, USA
- F.M.Kirby Neurobiology Center, Boston Children’s Hospital, Boston, MA, 02115, USA
| | - Erin L. Heinzen
- Institute for Genomic Medicine, Columbia University, New York, NY, 10032, USA
- Department of Pathology and Cell Biology, Columbia University, New York, NY, 10032, USA
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